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WO2012017697A1 - Circuit de mise en oeuvre de batteries en parallèle, et système de batteries - Google Patents

Circuit de mise en oeuvre de batteries en parallèle, et système de batteries Download PDF

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Publication number
WO2012017697A1
WO2012017697A1 PCT/JP2011/004481 JP2011004481W WO2012017697A1 WO 2012017697 A1 WO2012017697 A1 WO 2012017697A1 JP 2011004481 W JP2011004481 W JP 2011004481W WO 2012017697 A1 WO2012017697 A1 WO 2012017697A1
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WO
WIPO (PCT)
Prior art keywords
battery
parallel
charging
discharging
fet
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/JP2011/004481
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English (en)
Inventor
Takehito Ike
Takeshi Nakashima
Ryuzo Hagihara
Chie Sugigaki
Hiromichi Namikoshi
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Sanyo Electric Co Ltd
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Sanyo Electric Co Ltd
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Filing date
Publication date
Application filed by Sanyo Electric Co Ltd filed Critical Sanyo Electric Co Ltd
Publication of WO2012017697A1 publication Critical patent/WO2012017697A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/44—Methods for charging or discharging
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/0029—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with safety or protection devices or circuits
    • H02J7/00304—Overcurrent protection
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/0029—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with safety or protection devices or circuits
    • H02J7/0034—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with safety or protection devices or circuits using reverse polarity correcting or protecting circuits
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/34—Parallel operation in networks using both storage and other DC sources, e.g. providing buffering
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the invention relates to a battery parallel-operation circuit used to connect plural battery units in parallel to one another.
  • the invention also relates to a battery system using a battery parallel-operation circuit.
  • JP2002-142353A discloses a system using parallel-connected plural battery units each of which includes one or more secondary batteries.
  • Fig. 12 shows apparatus 900 using plural battery units connected in parallel to one another.
  • battery units 901 to 903 are connected in parallel to one another.
  • the output of battery units 901 to 903 drive load 910 in apparatus 900.
  • Battery units 901 to 903 are charged by charging circuit 911 in apparatus 900.
  • apparatus 900 using battery units 901 to 903 is configured so that each battery unit can be replaced. For instance, the user of apparatus 900 can change only battery unit 901 when necessary.
  • battery units are not replaced at all, the battery units are substantially uniform in terms of their characteristics because all the battery units are charged and discharged equally.
  • the characteristics of the battery units in apparatus 900 may be non-uniform.
  • a battery unit to be newly provided as battery unit 901 may possibly have a significantly greater open circuit voltage than battery units 902 and 903 that are not replaced with new ones. In this case, replacement of battery unit 901 with the new one may cause a relatively large current to flow from new battery unit 901 to battery units 902 and 903.
  • battery units 901 to 903 are formed by using secondary batteries with relatively large internal resistances (e.g., lead-acid batteries), a large current that may deteriorate or damage the battery units is unlikely to flow even after the above-described battery-unit replacement.
  • secondary batteries with relatively small internal resistances e.g., lithium-ion batteries and nickel-metal-hydride batteries
  • a large current is more likely to flow between the battery units and to deteriorate or damage the battery units after the above-described battery-unit replacement.
  • An aspect of the invention provides a battery parallel-operation circuit that comprises: a first line electrically coupled to, in parallel to one another, a plurality of battery units that are electrically connectable to the battery parallel-operation circuit, and configured to supply charging current to the plurality of battery units from a power source that is electrically connectable to the battery parallel-operation circuit, wherein the first line connecting the plurality of battery units in parallel to one another comprises a plurality of charging backflow prevention circuits each configured to allow the charging current to flow from the first line to a corresponding one of the battery units but to prevent reverse current from flowing from the battery unit to the first line.
  • Another aspect of the invention provides a battery system that comprises the battery parallel-operation circuit and a plurality of battery units.
  • Fig. 1 is a schematic, overall circuit diagram illustrating a battery system according to an embodiment.
  • Fig. 2 is a diagram illustrating various examples of the internal configuration of a single battery unit.
  • Fig. 3 is a schematic diagram illustrating the configuration of an apparatus using the battery system.
  • Fig. 4 is a circuit diagram illustrating a battery parallel-connection circuit according to the first example.
  • Fig. 5 is a diagram illustrating an internal circuit and a peripheral circuit for each single driver circuit according to the first example.
  • Fig. 6 is a diagram illustrating regular charging operations in the battery parallel-connection circuit according to the first example.
  • Fig. 7 is a diagram illustrating non-uniformity charging operations in the battery parallel-connection circuit according to the first example.
  • Fig. 1 is a schematic, overall circuit diagram illustrating a battery system according to an embodiment.
  • Fig. 2 is a diagram illustrating various examples of the internal configuration of a single battery unit.
  • Fig. 3 is a schematic diagram illustrating the configuration
  • FIG. 8 is a diagram illustrating regular discharging operations in the battery parallel-connection circuit according to the first example.
  • Fig. 9 is a diagram illustrating non-uniformity discharging operations in the battery parallel-connection circuit according to the first example.
  • Fig. 10 is a diagram illustrating non-uniformity charging and discharging operations in the battery parallel-connection circuit according to the first example.
  • Fig. 11 is a diagram illustrating a modification of the parallel-connected circuit according to the first example.
  • Fig. 12 is a diagram illustrating a parallel-connected circuit according to the second example.
  • Fig. 13 is a diagram illustrating a parallel-connected circuit according to the fourth example.
  • Fig. 14 is a diagram illustrating a parallel-connected circuit according to the fifth example.
  • Fig. 15 is a diagram illustrating operation of the parallel-connected circuit according to the fifth example
  • Fig. 16 is a diagram illustrating a modification of the parallel-connected circuit according to the fifth example.
  • Fig. 17 is a diagram related to a conventional technique and illustrating an apparatus using plural battery units.
  • Fig. 18 is a circuit diagram related to a sixth example and used in a simulation.
  • Fig. 19 is a table related to the sixth example and showing characteristics of a PTC thermistor used in the simulation.
  • Fig. 20 shows graphs related to the sixth example and describing the result of a first simulation.
  • Fig. 21 shows graphs related to the sixth example and describing the result of a second simulation.
  • Fig. 1 shows a circuit diagram illustrating schematically an overall battery system according to an embodiment.
  • Controller 1 including an arithmetic processing unit and the like monitors the state of controlled unit 2, and controls the operations of various portions of controlled unit 2.
  • Controlled unit 2 includes switch unit 3, power converter circuit 4, plural battery units, and plural breakers corresponding respectively to plural battery units.
  • Switch unit 3 includes parallel-connected circuit 5 and switching elements 6 to 8.
  • Controlled unit 2 is electrically coupled to solar cell 9, diode 10, power-supply circuit (source of AC voltage in this embodiment) 11, and load 12.
  • Those diodes used in this embodiment are, for instance, PN-junction-type diodes, but diodes of other types may be used instead.
  • the plural battery units provided in controlled unit 2 are electrically coupled to parallel-connected circuit 5 via plural breakers respectively.
  • the plural battery units are electrically coupled in parallel to one another via parallel-connected circuit 5.
  • Two or more battery units are to be electrically coupled in parallel to one another via parallel-connected circuit 5. That is, two, three, four, five, six, or more battery units are to be connected in that way.
  • three battery units are connected in that way unless mentioned otherwise, and the three battery units are denoted by reference numerals BT[1] to BT[3].
  • the breaker corresponding to battery unit BT[i] is denoted by reference numeral BR[i].
  • the letter i in those reference numerals represents an integer.
  • Battery unit BT[1] includes one or more secondary batteries each of which may have a quite small internal resistance. If battery unit BT[1] includes plural secondary batteries, the plural secondary batteries may form any of the following circuits: a series-connected circuit of the second batteries such as one shown in Fig. 2A; a parallel-connected circuit of the second batteries such as one shown in Fig. 2B; and a combination circuit including both series-connected and parallel-connected circuits such as one shown in Fig. 2C.
  • the secondary batteries may include rechargeable batteries.
  • Lithium-ion batteries and nickel-metal-hydride batteries are examples of the secondary batteries having a quite small internal resistance.
  • Battery unit BT[1] has a negative output terminal and a positive output terminal, and outputs a positive voltage from the positive output terminal with the potential of the negative output terminal used as a reference. Voltage mentioned in this embodiment is a voltage based on the potential at a reference potential point.
  • each battery unit is schematically shown as a single battery. However, each battery unit may include series-connected plural batteries, parallel-connected plural batteries, or a combination of both.
  • the positive output terminal of battery unit BT[i] is electrically coupled to branch point 15[i] via breaker BR[i].
  • Branch point 15[i] is electrically coupled to main line L1 via switching element 30[i] (i is 1, 2, or 3 in this embodiment).
  • One switching element 30[i] is provided for each battery unit, and is coupled in series between the corresponding battery unit and main line L1.
  • Branch point 15[i] is electrically coupled to sub-line L2 via resistive element 20[i] (i is 1, 2, or 3 in this embodiment).
  • One resistive element 20[i] is provided for each battery unit, and is connected in series between the corresponding battery unit and sub-line L2.
  • battery units BT[1] to BT[3] are electrically coupled in parallel to one another via main line L1, and are electrically coupled in parallel to one another via sub-line L2 as well.
  • resistive elements 20[1] to 20[3] used in this embodiment are identical to one another and switching elements 30[1] to 30[3] are identical to one another.
  • Charging line LA is a line through which either the charging current from solar cell 9 or the charging current from power converter circuit 4 flows.
  • Battery unit BT[i] is charged by the charging current flowing into battery unit BT[i] through charging line LA.
  • Discharging line LB is a line through which the electric current supplied from battery unit BT[i] to load 12 (i.e., the discharging current of battery unit BT[i]) flows. Note that the charging of battery unit BT[i] means the charging of the secondary battery included in battery unit BT[i], and the discharging of battery unit BT[i] means the discharging of the secondary battery included in battery unit BT[i].
  • Charging line LA is connected to the output terminal of power converter circuit 4 via switching elements 6 and 7, and is also connected to the cathode of diode 10 via switching element 6.
  • Discharging line LB is connected to load 12 via switching element 8.
  • Any semiconductor switches or mechanical switches may be used as the switching elements in the battery system.
  • MOSFETs metal-oxide-semiconductor field-effect transistors
  • the state of electrical continuity in FETs in switch unit 3 is controlled by controller 1.
  • a parasitic diode is provided to each FET. This can be interpreted as either that each FET has a built-in parasitic diode, or that the parasitic diode is a circuit element electrically coupled in parallel to the FET.
  • the parasitic diode of FET 6 is connected in parallel to FET 6 with the forward direction of the parasitic diode set in the direction from the source to drain of FET 6.
  • connection point of each of charging backflow prevention circuit 20[1] to 20[3] (hereinafter also referred simply to circuits 20[1] to 20[3]) and the charging line LA is connected to the source of FET 6 via charging line LA.
  • the drains of FETs 6 and 7 are connected to each other at connection point 16.
  • the source of FET 7 is connected to the output terminal of the power converter circuit 4.
  • FET 7 is provided to prevent backflow electric current from connection point 16 toward power converter circuit 4. Without FET 7, an overcurrent caused by the output of solar cell 9 is sometimes applied to power converter circuit 4, and damages power converter circuit 4.
  • Providing FET 7 can prevent such overcurrent applied to power converter circuit 4 from damaging power converter circuit 4.
  • providing of FET 7 is expected to have an effect to reduce power consumption in power converter circuit 4.
  • Connection point 16 is connected to the cathode of diode 10, and the anode of diode 10 is connected to the output terminal of solar cell 9.
  • power converter circuit 4 converts the AC electric power supplied by AC voltage source 11 to DC electric power. Power converter circuit 4 outputs the DC voltage and DC current thus obtained out through its output terminal.
  • Solar cell 9 converts light such as sunlight to DC electric power, and outputs the DC voltage and DC current thus obtained out through its output terminal.
  • controller 1 turns on both FETs 6 and 7.
  • either the output current of solar cell 9 or the output current of power converter circuit 4 is supplied to charging line LA as the charging current for battery unit BT[i].
  • controller 1 may turn on only FET 6 of the above-mentioned two FETs 6 and 7, and thus supplies the output current of solar cell 9 to charging line LA as the charging current for battery unit BT[i].
  • both FETs 6 and 7 are turned on unless mentioned otherwise. It is, however, not essential to turn FET 7 on. Similar actions to those caused by turning on only FET 6 of two FETs 6 and 7 can be caused by turning on both FETs 6 and 7.
  • Solar cell 9 forms a first electric-power source whereas both source of AC voltage 11 and power converter circuit 4 together form a second electric-power source. Nevertheless, any of the two electric-power sources may be omitted.
  • connection point of each of discharging backflow prevention circuits 30[1] to 30[3] (hereinafter also referred simply to circuits 30[1] to 30[3]) and the discharging line LB is connected to the drain of FET 8 via discharging line LB.
  • the source of FET 8 is connected to load 12.
  • controller 1 If battery unit BT[i] needs discharging, or, to put it differently, if it is necessary to supply electric power to load 12, controller 1 turns on FET 8. Thus the discharging current of battery unit BT[i] is supplied to load 12 either through main line L1 or through sub-line L2. If controller 1 judges that the discharging of battery unit BT[i] is not necessary, or if controller 1 judges that it is necessary to prohibit the discharging of battery unit BT[i], controller 1 turns off FET 8. For instance, if battery unit BT[i] is in an abnormal state (including the event of overcurrent), or if an excessively large current passes through FET 8, the discharging of battery unit BT[i] is prohibited.
  • Controller 1 is capable of controlling the continuity of each of FETs 6 to 8 in accordance with the output voltages of battery units BT[1] to BT[3]. Controller 1 is capable of detecting the output voltage of battery unit BT[i] either periodically or at any timing by use of, for instance, voltage-detection sensors S[i].
  • Voltage-detection sensors S[1] to S[3] output output-voltage information of battery units BT[1] to BT[3].
  • the output-voltage information mentioned above includes not only the information on the output voltages but also the broader information that can be used to specify the output voltages.
  • Controller 1 receives the output-voltage information. Controller 1 may receive the output-voltage information directly from voltage-detection sensors S[1] to S[3]. Alternatively, a third apparatus may be provided to receive the output-voltage information of battery units BT[1] to BT[3]. Then, the third apparatus processes the data, and then sends the processed data to controller 1.
  • Breaker BR[i] is a mechanical relay or the like that is connected in series between battery unit BT[i] and branch point 15[i]. Breaker BR[i] is capable of cutting the electrical connection between battery units BT[i] and branch point 15[i] when necessary. For instance, breaker BR[i] cuts the electrical connection between battery unit BT[i] and branch point 15[i] if either the charging current or the discharging current for battery unit BT[i] is abnormally large, or if any abnormal signal is sent from battery unit BT[i], or if a predetermined signal to cut the connection is sent from controller 1.
  • Both controller 1 and controlled unit 2 may be considered as constituent elements of the battery system shown in Fig. 1.
  • battery system BS as the battery system shown in Fig. 1 may be built into apparatus AP that includes load 12.
  • Apparatus AP is any apparatus driven by the output power of the secondary batteries in the battery system BS.
  • Some examples of apparatus AP are electrically-driven vehicles, power tools, PCs, mobile phones, and PDAs.
  • Battery units BT[1] to BT[3] are attachable to or detachable from apparatus AP independently of each other. Each battery unit can be changed from to a new one. To put it differently, the user of apparatus AP can remove, from apparatus AP, battery unit BT[1] that is currently set in apparatus AP, and attach another battery unit in apparatus AP as a new battery unit BT[1] (battery units BT[2] and BT[3] can be treated similarly). Once battery unit BT[1] is removed from apparatus AP, the electrical connection between battery unit BT[1] and battery system BS is cut off completely.
  • the output voltages of battery units BT[1] to BT[3] may be 55 V, 50 V, and 50 V respectively. Note that the expressions 55 V and 50 V mean 55 volts and 50 volts respectively (the same applies to 49 V and the like described later).
  • Circuit 20[i] is connected in series on the line connecting charging line LA to branch point 15[i].
  • Circuit 20[i] allows the charging current to flow from charging line LA to battery unit BT[i], but prevents the reverse current from flowing from battery unit BT[i] to charging line LA.
  • Circuit 30[i] is connected in series on the line connecting discharging line LB to branch point 15[i].
  • Circuit 30[i] allows the discharging current to flow from battery unit BT[i] to discharging line LB, but prevents the reverse current from flowing from discharging line LB to battery unit BT[i]. Examples of the internal configurations of circuits 20[i] and 30[i] are described in detail later. In the following description, for the sake of descriptive convenience, FETs 6 and 7 are also referred to as charger FETs 6 and 7 whereas FET 8 is also referred to as discharger FET 8.
  • FIG. 4 illustrates the internal circuit of parallel-connection circuit 5 according to the first example.
  • Circuit 20[i] and circuit 30[i] shown in Fig. 1 are referred to respectively as circuit 20A[i] and circuit 30A[i] in the first example.
  • circuits 20A[1] to 20A[3] are identical to one another whereas the configurations of circuits 30A[1] to 30A[3] are identical to one another.
  • Circuit 20A[i] includes FET 21[i], which is the same switching element as charger FET 6.
  • Circuit 30B[i] includes FET 31[i], which is the same switching element as charger FET 6. Accordingly, as in the case of FET 6, a parasitic diode is provided to FET 21[i].
  • the parasitic diode of FET 21[i] is connected in parallel to FET 21[i] with the forward direction of the parasitic diode set in the direction from the source to the drain of FET 21[i].
  • a parasitic diode is also provided to FET 31[i].
  • the parasitic diode of FET 31[i] is connected in parallel to FET 31[i] with the forward direction of the parasitic diode set in the direction from the source to the drain of FET 31[i]. If the parasitic diode is considered as a circuit element connected in parallel to each FET as described above, FET 21[i] and the parasitic diode of FET 21[i] together form a parallel circuit. Likewise, FET 31[i] and the parasitic diode of FET 31[i] together form a parallel circuit.
  • the drain of FET 21[i] is connected to the corresponding branch point 15[i] whereas the source of each FET 21[i] is connected to charging line LA. Accordingly, while both charger FETs 6 and 7 are on, turning on FET 21[i] makes FET 21[i] form a current path for the charging current from charging line LA to the corresponding battery unit BT[i]. Note that even if FET 21[i] is off, a current path for the charging current from charging line LA to battery units BT[i] is secured by the existence of the parasitic diode of FET 21[i].
  • the source of FET 31[i] is connected to branch point 15[i] whereas the drain of FET 31[i] is connected to discharging line LB.
  • Charging backflow prevention circuit 20A[i] is provided with a driver circuit (charging driver circuit) configured to control the turning on/off of FET 21[i].
  • discharging backflow prevention circuit 30A[i] is provided with a driver circuit (discharging driver circuit) to control the turning on/off of FET 31[i].
  • Fig. 5 illustrates an internal circuit and a peripheral circuit for each single driver circuit.
  • FET 40 is either the FET in a charging backflow prevention circuit or the FET in a discharging backflow prevention circuit.
  • driver circuit 50 shown in Fig. 5 is the driver circuit in circuit 20A[i]
  • FET 40 is FET 21[i].
  • driver circuit 50 shown in Fig. 5 is the driver circuit in circuit 30A[i]
  • FET 40 is FET 31[i].
  • connection point 41 The source of FET 40 is connected to connection point 41 whereas the drain of FET 40 is connected to connection point 42.
  • driver circuit 50 shown in Fig. 5 is the driver circuit in circuit 20A[i]
  • connection point 41 is connected to charging line LA
  • connection point 42 is connected to branch point 15[i].
  • driver circuit 50 shown in Fig. 5 is the driver circuit in circuit 30A[i]
  • connection point 41 is connected to branch point 15[i]
  • connection point 42 is connected to discharging line LB.
  • Driver circuit 50 includes: transistor 51, which is an n-type bipolar transistor; diode 52; and resistive elements 53 to 56.
  • the emitter of transistor 51 is connected to connection point 41, and the base thereof is connected to the anode of diode 52 via resistive element 53.
  • collector transistor 51 is connected to the gate of FET 40 via resistive element 54, and is also connected to the anode of diode 52 via resistive elements 55 and 56 in this order.
  • the cathode of diode 52 is connected to connection point 42.
  • connection points 41 and 42 are denoted by Vi and Vo respectively.
  • the gate voltage, the source voltage, and the drain voltage of FET 40 are denoted by VG, VS, and VD respectively.
  • the base voltage, the emitter voltage, and the collector voltage of transistor 51 are denoted by VB, VE, and VC respectively.
  • the forward voltage drop of diode 52 is denoted by Vf.
  • the value of Vf is 0.7 V approximately. So, in the following description, the value of Vf is assumed to be 0.7 V.
  • a voltage that is higher than the emitter voltage of transistor 51 by an amount of voltage VBEO i.e., a voltage (Vi + VBEO) needs to be applied to the base of transistor 51.
  • Voltage VBEO is 0.7 V approximately. So, in the following description, voltage VBEO is assumed to be 0.7 V.
  • voltage V1 is the voltage of a connection point between resistive elements 53 and 56, and is equal to the voltage of the anode of diode 52.
  • voltage Vx is the voltage of the connection point between resistive elements 55 and 56.
  • Either controller 1 or controlled unit 2 always applies a voltage (Vi + VUP), that is, a voltage that is higher than voltage Vi by an amount VUP, to the connection point between resistive elements 55 and 56.
  • a constant-voltage generating circuit (not illustrated) or the like is used.
  • VUP is a positive voltage, and is assumed to be 12 V in the following description.
  • Driver circuit 50 is configured to turn off FET 40 while transistor 51 is on, and to turn on FET 40 while transistor 51 is off.
  • collector voltage VC of transistor 51 is approximately equal to the voltage of connection point 41 Vi (strictly, collector voltage VC is slightly higher than voltage Vi).
  • diode 52 is turned on or off depends on the value of voltage V1 of a connection point between resistive elements 53 and 56.
  • transistor 51 is turned on or off depends on the value of base voltage VB of transistor 51.
  • diode 52 is turned on and transistor 51 is turned off. Conversely, if a forward-direction voltage is applied to FET 40, that is, if voltage Vo is higher than voltage Vi, electric current is drawn in from the connection point between resistive elements 53 and 56 to the base side of transistor 51. Consequently, diode 52 is turned off and transistor 51 is turned on. When transistor 51 is turned on, collector voltage Vc of transistor 51 is almost equal to voltage Vi. Consequently, FET 40 is turned off.
  • the circuit may perform an intermediate operation between the circuit operations at the time when "Vo ⁇ Vi" and the circuit operations at the time when "Vo > Vi.”
  • the state of FET 40 may be an intermediate state between the ON state and the OFF state.
  • driver circuit 50 in each charging backflow prevention circuit 20A[i] operates in the following way. If the voltage of charging line LA is higher than the output voltage of the corresponding battery unit BT[i], driver circuit 50 turns on FET 21[i]. Conversely, if the voltage of charging line LA is lower than the output voltage of the corresponding battery unit BT[i], driver circuit 50 turns off FET 21[i]. If FET 21[i] is off, the function of the parasitic diode of FET 21[i] makes circuit 20A[i] function as a simple rectifier diode. Driver circuit 50 in discharging backflow prevention circuit 30A[i] operates in a similar way.
  • driver circuit 50 turns on FET 31[i]. Conversely, if the voltage of discharging line LB is higher than the output voltage of battery unit BT[i], driver circuit 50 turns off FET 31[i]. If FET 31[i] is turned off, the function of the parasitic diode of FET 31[i] makes circuit 30A[i] function as a simple rectifier diode.
  • the voltage of charging line LA means the potential of charging line LA.
  • the voltage of discharging line LB means the potential of discharging line LB.
  • the output voltage of battery unit BT[i] means the potential of the positive output terminal of battery unit BT[i].
  • circuit 20A[i] each including driver circuit 50, the following normal charging operations are performed.
  • the normal charging operations are to charge battery unit BT[i] and are performed when the output voltages of battery units BT[1] to BT[3] are uniform (i.e., exactly or substantially the same).
  • driver circuits 50 of circuits 20A[1] to 20A[3] turn on their respective FETs 21[1] to 21[3], and the charging current flows through FETs 21[1] to 21[3] into battery units BT[1] to BT[3] respectively.
  • the charging current for battery unit BT[i] is supplied to battery unit BT[i] through FET 21[i] as described above, so that the loss at circuit 20A[i] is reduced from the case where the charging current is supplied to battery unit BT[i] through a diode.
  • circuit 20A[i] including driver circuit 50 With the existence of circuit 20A[i] including driver circuit 50, the following non-uniform charging operations are performed.
  • the non-uniform charging operations are to charge battery unit BT[i] and are performed when the output voltages of battery units BT[1] to BT[3] are non-uniform.
  • charging operations performed under these conditions are non-uniform charging operations. If, under the conditions, charger FETs 6 and 7 are turned on, charging line LA has a potential that depends on the lowest one of the output voltages of battery units BT[1] to BT[3].
  • both the open circuit voltage of solar cell 9 and the open circuit voltage of power converter circuit 4 are higher than the output voltages of battery units BT[1] to BT[3], so that FET 21[2] is turned on, and charging line LA has a potential equal to the sum of the output voltage of battery unit BT[2] and the voltage drop at FET 21[2].
  • charging line LA has a potential of 50.3 V.
  • both of FETs 21[1] and 21[3] are turned off, so that the charging current supplied from solar cell 9 or the like flows only into battery unit BT[2] through FET 21[2].
  • circuits 20A[1] and 20A[3] as simple diodes at this time prevent both the generation of electric current from battery units BT[1] and BT[3] to battery units BT[2] and the generation of electric current from battery unit BT[1] to battery unit BT[3].
  • circuit 30A[i] including driver circuit 50 "normal discharging operations" are performed. Normal discharging operations are to discharge battery unit BT[i] and are to be performed when the output voltages of battery units BT[1] to BT[3] are uniform. Note that the voltage of the source side of FET 8-the side that the electric current is drawn in-is lower than the output voltage of battery unit BT[i].
  • driver circuits 50 of circuit 30A[1] to 30A[3] turn on their respective FETs 31[1] to 31[3], and thus the discharging current from battery units BT[1] to BT[3] are supplied to load 12 respectively through FETs 31[1] to 31[3] and discharger FET 8.
  • the discharging current to load 12 is supplied through FET 31[i] to load 12 in the above-described way, so that the loss at circuit 30A[i] is reduced from the case where the discharging current is supplied through diodes.
  • circuit 30A[i] including driver circuit 50 non-uniform discharging operations are performed.
  • the non-uniform discharging operations are to charge battery unit BT[i] and are performed when the output voltages of battery units BT[1] to BT[3] are non-uniform.
  • charging line LB has a potential that depends on the lowest one of the output voltages of battery units BT[1] to BT[3]. Specifically, FET 31[1] is turned on, and charging line LB has a potential equal to the difference between the output voltage of battery unit BT[1] and the voltage drop at FET 31[1]. In the case shown in Fig. 9, charging line LB has a potential of 54.7 V.
  • both of FETs 31[2] and 31[3] are turned off, so that the discharging current from battery unit BT[1] is supplied to load 12 through FET 31[1] and discharger FET 8.
  • the functions of circuits 30A[2] and 30A[3] as simple diodes at this time prevent both the generation of electric current flowing from battery units BT[1] and BT[3] to battery units BT[2] and the generation of electric current flowing from battery unit BT[1] to battery unit BT[3].
  • Controller 1 is capable of turning on charger FETs 6 and 7 together with discharger FET 8 to perform simultaneously both the charging of any of battery units BT[1] to BT[3] and the discharging of any of battery units BT[1] to BT[3]. If, for instance, the output voltages of battery units BT[1] to BT[3] are 55 V, 50 V, and 52 V respectively as Fig. 10 shows, turning on FETs 6 to 8 together triggers the simultaneous execution of both the non-uniform charging operations corresponding to Fig. 7 and the non-uniform discharging operations corresponding to Fig. 9.
  • circuits 20A[i] and 30A[i] prevent excessively large electric current from flowing between battery units. Note that both the charging current from solar cell 9 or the like and the discharging current to load 12 flow through FETs included in circuits 20A[i] and 30A[i], so that the loss can be reduced from the case where simple diodes are used.
  • circuits 20A[i] and 30A[i] each including driver circuit 50 preferentially charge the battery units with lower output voltages and preferentially discharge the battery units with higher output voltages. Consequently, even without any special control performed by the controller system, the non-uniform output voltages caused by the battery-unit replacement or the like can be corrected automatically in the processes of the charging of or the discharging of the battery units.
  • diode 23[1] with the forward direction set to be from the source to the drain of FET 21[1] may be connected in parallel to FET 21[1].
  • diode 33[1] with the forward direction set to be from the source to the drain of FET 31[1] may be connected in parallel to FET 31[1].
  • FETs 21[2], 21[3], 31[2], and 31[3]. The same also applies to the second and the third examples to be described below.
  • FIG. 12 illustrates the internal circuit of parallel-connection circuit 5 according to the second example.
  • Circuit 20[i] and circuit 30[i] shown in Fig. 1 are referred to respectively as circuit 20B[i] and circuit 30B[i] in the second example.
  • Circuit 20B[i] is formed by omitting driver circuit 50 (see Fig. 5) from circuit 20A[i] described in the first example.
  • circuit 30B[i] is formed by omitting driver circuit 50 (see Fig. 5) from circuit 30A[i] described in the first example.
  • Circuit 20B[i] has basically the same configuration as that of circuit 20A[i] except that no driver circuit 50 is provided whereas circuit 30B[i] has basically the same configuration as that of circuit 30A[i] except that no driver circuit 50 is provided.
  • the elements and lines in controlled unit 2 are connected to one another in the second example in a similar manner to the one described in the first example.
  • unillustrated voltage-detection sensors detect the output voltages of battery units BT[1] to BT[3].
  • controller 1 controls the continuity of each of FETs 21[1] to 21[3] included respectively in circuits 20B[1] to 20B[3] and the continuity of each of FETs 31[1] to 31[3] included respectively in circuits 30B[1] to 30B[3].
  • controller 1 may control the continuity of each of FETs 21[i] and 31[i] so that the continuity of FETs 21[i] and 31[i] in the second example are the same as those in the first example irrespective of whether controller 1 performs the control in the normal charging operations, the non-uniform charging operations, the normal discharging operations, or the non-uniform discharging operations (see Figs. 6 to 10).
  • V[i] means the output voltage of battery unit BT[i] detected by voltage-detection sensor S[i].
  • Voltage-detection sensor detects output voltages V[1] to V[3]. Here, the detection errors are ignored.
  • Controller 1 identifies maximum voltage VMAX and minimum voltage VMIN of output voltages V[1] to V[3], and calculates the voltage difference (VMAX - VMIN).
  • the voltage difference (VMAX - VMIN) is an indicator of the variation in the output voltage among battery units BT[1] to BT[3].
  • Controller 1 compares the voltage difference (VMAX - VMIN) with a predetermined reference voltage difference VTH (note that VTH > 0).
  • controller 1 judges that all the battery units are in the uniform voltage state. In contrast, if the inequality for state determination does not hold true, controller 1 judges that the battery units are in the non-uniform voltage state.
  • the uniform voltage state mentioned above refers to a state where battery units BT[1] to BT[3] have relatively small variation in output voltage.
  • the non-uniform voltage state refers to a state where battery units BT[1] to BT[3] have relatively large variation in output voltage.
  • controller 1 judges that the battery units are in the uniform voltage state, controller 1 turns on all of FETs 21[1] to 21[3]. If, under these conditions, controller 1 turns on charger FETs 6 and 7, the normal charging operations can be performed in the same manner as in the case of the first example.
  • controller 1 judges that the battery units are in the uniform voltage state, controller 1 turns on all of FETs 31[1] to 31[3]. If, under these conditions, controller 1 turns on charger FET 8, the normal discharging operations can be performed in the same manner as in the case of the first example.
  • controller 1 judges that battery units are in the non-uniform voltage state, controller 1 turns on only the FET corresponding to the minimum voltage VMIN among FETs 21[1] to 21[3], and turns off the other FETs. If, under these conditions, charger FETs 6 and 7 are turned on, the non-uniform charging operations that are similar to the ones in the first example are performed. Specifically, the battery units with lower output voltages are preferentially charged to correct the non-uniformity in the output voltage. Alternatively, if controller 1 judges that the battery units are in the voltage non-uniform state, controller 1 may turn off all the FET 21[1] to 21[3]. Also in this case, the battery units with lower output voltages are charged preferentially through parasitic diodes of FETs 21[1] to 21[3]. Thus, the non-uniformity in the output voltage is gradually corrected.
  • FET 21[2] may be turned on in addition to FET 21[1] that has been on (in the same applies to a case where output voltages V[1] and V[3] become equal to each other).
  • FET 21[1] and V[2] become equal to each other, but output voltages V[1] and V[3] are still different from each other.
  • a state where FET 21[1] is on while both of FETs 21[2] and 21[3] are off may be kept.
  • controller 1 judges that battery units are in the non-uniform voltage state, controller 1 turns on only the FET corresponding to maximum voltage VMAX among FETs 31[1] to 31[3], and turns off the other FETs. If, under these conditions, charger FET 8 is turned on, the non-uniform discharging operations that are similar to the ones in the first example are performed. Specifically, the battery units with higher output voltages are preferentially discharged to correct the non-uniformity in the output voltage. Alternatively, if controller 1 judges that the battery units are in the voltage non-uniform state, controller 1 may turn off all the FETs 31[1] to 31[3]. Also in this case, the battery units with higher output voltages are discharged preferentially through parasitic diodes of FETs 31[1] to 31[3]. Thus, the non-uniformity in the output voltage is gradually corrected.
  • the second example has the same advantageous effects as those obtainable in the first example.
  • controller 1 of the second example must control the FETs so as to reflect the non-uniform output voltages of the battery units.
  • the second example needs no driver circuit 50 shown in Fig. 5, so that there is a possibility that the size of the circuit can be made smaller.
  • a third example is described.
  • the internal circuit of parallel-connection circuit 5 according to the third example is the same as the one shown in Fig. 12.
  • the following description focuses on the differences between the second and the third examples.
  • Controller 1 in the third example controls the continuity of FETs 21[1] to 21[3] and 31[1] to 31[3] on the basis of the length of time passed after the last replacing of battery units without using the detected output voltages of battery unit BT[i].
  • the battery unit BT[i] that is removed from apparatus AP shown in Fig. 3 during the battery-unit replacement is referred to as the old battery unit while the battery unit that is attached to apparatus AP as the new battery unit BT[i] is referred to as the new battery unit.
  • Such a state is referred to as the reference state.
  • the output voltages of all the battery units BT[1] to [3] are equal to one another.
  • controller 1 turns on all of FETs 21[1] to 21[3] and FETs 31[1] to 31[3].
  • Controller 1 is capable of detecting the occurrence of the replacement of battery unit BT[i], that is, the replacement of the old battery unit with a new battery unit and the attachment of the new battery unit in apparatus AP. Any method can be used for the detection.
  • voltage measuring units VM[i] to measure the voltages at branch points 15[i] are provided in parallel-connected circuit 5.
  • voltage measuring units VM[1] to VM[3] measure the voltages of branch points 15[1] to 15[3] respectively.
  • Each measured value is output as branch-point voltage information.
  • the branch-point voltage information mentioned above includes not only the voltage at the branch point but also broader information to be used in specifying the voltage at the branch point.
  • Controller 1 receives the branch-point voltage information. Controller 1 may receive the branch-point voltage information directly from voltage measuring units VM[1] to VM[3].
  • a third apparatus may be provided to receive branch-point voltage information from voltage measuring units VM[1] to VM[3]. The third apparatus processes the data when necessary, and then sends the data to controller 1. On the basis of the branch-point voltage information thus received, controller 1 detects the attachment of a new battery unit in apparatus AP.
  • the casing (not illustrated) to hold battery unit BT[i] may be provided with mechanical switches or the like to detect the existence or the non-existence of battery unit BT[i].
  • controller 1 Upon detecting the attachment of a new battery unit in apparatus AP, controller 1 starts measuring, by use of timer 41 provided thereto, length of time TP that has passed since the new battery unit is attached to apparatus AP. When elapsed time TP does not exceed predetermined length of time TPTH, controller 1 judges that the battery units are in the non-uniform voltage state (note that TPTH > 0) and turns off all of FETs 21[1] to 21[3] and FETs 31[1] to 31[3]. If elapsed time TP exceeds predetermined length of time TPTH, controller 1 judges that the battery units are in the uniform voltage state and turns on all of FETs 21[1] to 21[3] and FETs 31[1] to 31[3].
  • measured elapsed time TP is reset to zero, and the measurement of elapsed time TP is resumed from the point of time at which the other new battery unit is attached to apparatus AP.
  • the third example has the same advantageous effects as those obtainable in the first example. Note that what distinguishes the third example from the first example is the FET control performed by controller 1 of the third example on the basis of the elapsed time TP. Nevertheless, the third example needs no driver circuit 50 shown in Fig. 5, so that there is a possibility that the size of the circuit can be made smaller.
  • FIG. 13 illustrates the internal circuit of parallel-connection circuit 5 according to the fourth example.
  • Circuit 20[i] and circuit 30[i] shown in Fig. 1 are referred to respectively as circuit 20C[i] and circuit 30C[i] in the second example.
  • circuits 20C[1] to 20C[3] are identical to one another whereas the configurations of circuits 30C[1] to 30C[3] are identical to one another.
  • circuit 20C[i] from each of circuits 20A[i] and 20B[i] is the providing of diode 25[i] in circuit 20C[i] in place of FET 21[i] provided in each of circuits 20A[i] and 20B[i].
  • circuit 30C[i] from each of circuits 30A[i] and 30B[i] is the providing of diode 35[i] in circuit 30C[i] in place of FET 31[i] provided in each of circuits 30A[i] and 30B[i].
  • the anode of diode 25[i] is connected to charging line LA whereas the cathode of diode 25[i] is connected to branch point 15[i].
  • the anode of diode 35[i] is connected to branch point 15[i] whereas the cathode of each diode 35[i] is connected to charging line LB.
  • the diodes provided in circuit 20C[i] and 30C[i] prevent excessively large current from flowing between battery units.
  • the functions of the diodes included in circuits 20C[i] and 30C[i] automatically correct the non-uniformity of output voltage gradually. This is because the battery units with lower output voltages are preferentially charged by the functions of the diodes while the battery units with higher output voltages are discharged preferentially by the functions of the diodes.
  • the discharging current and the charging current always flow through the diodes, so that the configuration of this fourth example has larger loss than in each of the cases of the first to the third examples.
  • charging line LA may be connected to each of branch points 15[1] to 15[3] via a resistive element for voltage-non-uniformity correction.
  • Fig. 14 shows an exemplary circuit diagram of a case where resistive elements for non-voltage-uniformity correction are provided in the parallel-connection circuit of any of the first, the second, and the third examples.
  • Resistive element 27[i] which is provided as a resistive element for voltage-non-uniformity correction, has an end connected to the source of FET 21[i] and the other end connected to the drain thereof.
  • Resistive element 27[i] may be considered as a constituent element of circuit 20[i], or may be considered as an element provided outside of circuit 20[i].
  • Each of resistive elements 27[1] to 27[3] has an arbitrarily determined resistance, but the resistance is at least larger than the on-resistance of the corresponding one of FETs 21[1] to 21[3].
  • the resistance of each of resistive element 27[i] and 27[j] should be determined so as to prevent electric current that may deteriorate battery units BT[i] and BT[j] from flowing between battery units BT[i] and BT[j] even if the output voltages of battery units BT[i] and BT[j] differ from one another.
  • resistive element 27[i] the non-uniformity of the output voltages of the battery units can be corrected by resistive element 27[i] as well.
  • the output voltages of battery units BT[1] to BT[3] are 55 V, 50 V, and 52 V respectively as shown in Fig. 15.
  • FETs 6 to 8 are turned on simultaneously, only FETs 21[2] and FET 31[1] of all the FET 21[1] to 21[3] and 31[1] to 31[3] are turned on as in the case shown in Fig. 10. Consequently, the charging current from solar cell 9 or the like flows into battery unit BT[2] through FET 21[2] while the discharging current from only battery unit BT[1] is supplied to load 12 through FET 31[1].
  • part of output current of battery units BT[1] flows into battery unit BT[2] through resistive element 27[1] and charging line LA and through the parallel circuit of resistive element 27[2] and FET 21[2].
  • This current flow also contributes to the correction of the non-uniformity of the output voltages.
  • charger FETs 6 and 8 are off, electric current flows from battery unit BT[1] into battery unit BT[2] through resistive elements 27[1] and 27[2].
  • the current may flow from battery unit BT[1] into battery unit BT[2] through resistive element 27[1] and the parasitic diode of FET 21[2], and the current may flow from battery unit BT[3] into battery unit BT[2] through resistive elements 27[3] and 27[2] as well as through the parasitic diode of FET 21[2].
  • the flows are not illustrated in Fig. 15 to prevent the diagram from becoming complicated.
  • the resistive elements for non-voltage-uniformity correction may be provided on the side of discharging line LB.
  • Discharging line LB may be connected to each of branch points 15[1] to 15[3] via a resistive element for voltage-non-uniformity correction.
  • Fig. 16 shows an exemplary circuit diagram of a case where resistive elements for non-voltage-uniformity correction are provided to discharging line LB of any of the first, the second, and the third examples.
  • Resistive element 37[i] which is provided as a resistive element for voltage-non-uniformity correction, has an end connected to the source of FET 31[i] and the other end connected to the drain thereof.
  • Resistive element 37[i] may be considered as a constituent element of circuit 30[i], or may be considered as an element provided outside of circuit 30[i].
  • Each of resistive elements 37[1] to 37[3] has a desired resistance, but the resistance is at least larger than the on-resistance of the corresponding one of FETs 31[1] to 31[3].
  • the resistance of each of resistive element 37[i] and 37[j] should be determined so as to prevent electric current that may deteriorate battery units BT[i] and BT[j] from flowing between battery units BT[i] and BT[j] even if the output voltages of battery units BT[i] and BT[j] differ from one another.
  • the circuit shown in Fig. 16 has the same effects that are obtainable by the circuit shown in Fig. 14.
  • Resistive elements with positive temperature characteristics may be used as resistive elements 27[1] to 27[3] or 37[1] to 37[3] (see Figs. 14 or 16), which are resistive elements for non-voltage-uniformity correction.
  • PTC positive temperature coefficient
  • PTC thermistors are thermistors with positive temperature characteristics (i.e., thermistors with a positive temperature coefficient).
  • the resistance of each thermistor changes with changes in temperature to a greater degree than the resistance of each ordinary resistive element (carbon-film resistors etc) used for obtaining a constant resistance.
  • the resistance of each PTC thermistor increases as the temperature of the PTC thermistor rises.
  • Fig. 18 is a diagram illustrating the circuit used in the simulations. The simulations include first and second simulations described later.
  • Battery unit 100 shown in Fig. 18 includes a series-connected circuit of batteries 101 and 102 whereas battery unit 110 includes a series-connected circuit of batteries 111 and 112.
  • the output voltage of the series-connected circuit of batteries 101 and 102 appears at the positive output terminal of battery unit 100 with the negative output terminal of battery unit 100 being the reference.
  • the output voltage of the series-connected circuit of batteries 111 and 112 appears at the positive output terminal of battery unit 110 with the negative output terminal of battery unit 110 being the reference.
  • the positive output terminals of battery units 100 and 110 are electrically coupled to each other via resistive element 120 whereas the negative output terminals of battery units 100 and 110 are electrically coupled directly to each other.
  • Each of batteries 101, 102, 111, and 112 is a secondary battery with a nominal output voltage of 48 V, a maximum output voltage of 52 V, and a minimum output voltage of 39 V. Accordingly, the maximum difference between the output voltages of battery units 100 and 110 is 26 V.
  • first to fourth sample elements are individually used as resistive element 120.
  • the first sample element is a PTC thermistor with a resistance of 6 ohm at a certain reference temperature, so that the first sample is referred to as a 6-ohm thermistor.
  • the 6-ohm thermistor has the same temperature as the reference temperature unless the 6-ohm thermistor generates heat due to power loss.
  • the second sample element which always has a resistance of 6 ohm irrespective of the temperature thereof, is referred to as a 6-ohm simple resistor.
  • the third sample element is a resistive element, which always has a resistance of 12.3 ohm irrespective of the temperature thereof, is referred to as a 12.3-ohm simple resistor.
  • the fourth sample element is a resistive element, which always has a resistance of 240 ohm irrespective of the temperature thereof, is referred to as a 240-ohm simple resistor.
  • the current ITM and the temperature TTM are measured values.
  • the resistance RTM and the heating value QTM are values calculated by assigning the measured values to the formulas.
  • Fig. 19 shows, in the 6-ohm thermistor, the changes in the applied voltage cause less change in the heat generated amount for the following reasons.
  • An increase in the voltage applied to a PTC thermistor such as the 6-ohm thermistor increases the current, and the larger current in turn increases the amount of generated heat.
  • the larger amount of generated heat in turn raises the temperature, and the higher temperature increases the resistance.
  • the increase in the resistance reduces the current, and eventually reduces amount of generated heat.
  • a decrease in the applied voltage reduces the current, and the smaller current in turn reduces the amount of generated heat.
  • the smaller amount of generated heat lowers the temperature, and the lower temperature in turn reduces the resistance.
  • the smaller resistance increases the current and eventually increases the amount of generated heat.
  • Figs. 20A and 20B show the results of a first simulation.
  • the first simulation assumes that the difference VDIF between the output voltages of battery units 100 and 110 is 26 V at the reference point of time.
  • arithmetic operations are performed to calculate, for each of the sample elements, the relationship between the time tEL elapsed from the reference point of time and the output-voltage difference VDIF.
  • arithmetic operations are performed to calculate, for each of the sample elements, the relationship between the elapsed time tEL and the heating value Q120 generated by the sample element.
  • dotted line GA[6], dashed line GA[12.3], dashed-dotted line GA[240], and solid line GA[TM] respectively represent the relationships between the elapsed time tEL and the output-voltage difference VDIF for the cases where the 6-ohm simple resistor, the 12.3-ohm simple resistor, the 240-ohm simple resistor, and the 6-ohm thermistor are used as resistive element 120.
  • dotted line GB[6], dashed line GB[12.3], dashed-dotted line GB[240], solid line GB[TM] respectively represent the relationships between the elapsed time tEL and heating value Q120 for the cases where the 6-ohm simple resistor, the 12.3-ohm simple resistor, the 240-ohm simple resistor, and the 6-ohm thermistor are used as resistive element 120.
  • each of batteries 101, 102, 111, and 112 is assumed to be not fully charged or nearly fully charged, and is assumed to be not fully discharged or nearly fully discharged.
  • the unit for the elapsed time tEL is an integral multiple of second.
  • the elapsed time tEL till the output voltage difference VDIF reaches 0.001 V is approximately 11 units time for the case where 6-ohm simple resistor is used as resistive element 120.
  • the corresponding elapsed time tEL for the 12.3-ohm simple resistor is approximately 24 units time, and that for the 6-ohm thermistor is also approximately 24 units time.
  • the length of one unit time depends on the capacity of battery 101 or the like.
  • the elapsed time tEL till the output voltage difference VDIF reaches 0.001 V is referred to as the voltage-balancing time.
  • the voltage-balancing time for the case where 240-ohm simple resistor is used as resistive element 120 is approximately 464 unit time.
  • the maximum value of the heating value Q120 is approximately 36 W (watts) for the case where 12.3-ohm simple resistor is used as resistive element 120.
  • the corresponding value for the 240-ohm simple resistor is approximately 3 W, and that for 6-ohm thermistor is also approximately 3 W.
  • a 6-ohm simple resistor is selected as the second sample element because the 6-ohm simple resistor is a simple resistor with a resistance that is equal to the resistance of the 6-ohm thermistor at the reference temperature.
  • a 240-ohm simple resistor is selected as the fourth sample element because the 240-ohm simple resistor is a simple resistor with a resistance that is approximately equal to the maximum resistance of the 6-ohm thermistor (approximately 240 ohm; see Fig. 19).
  • a 12.3-ohm simple resistor is selected as the third sample element because the 12.3-ohm simple resistor is a simple resistor with a voltage-balancing time that is approximately equal to the voltage-balancing time of the 6-ohm thermistor in the first simulation.
  • the use of the 12.3-ohm simple resistor as resistive element 120 leaves the voltage-balancing time approximately the same, but increases the maximum amount of generated heat by approximately 10 times.
  • Figs. 21A and 21B show the results of a second simulation.
  • the second simulation assumes that the difference VDIF between the output voltages of battery units 100 and 110 is 13 V at the reference point of time.
  • arithmetic operations are performed to calculate, for each of the sample elements, the relationship between the time tEL elapsed from the reference point of time and the output-voltage difference VDIF.
  • arithmetic operations are performed to calculate, for each of the sample element, the relationship between the elapsed time tEL and the heating value Q120 generated by the sample element.
  • dotted line GC[6], dashed line GC[12.3], dashed-dotted line GC[240], and solid line GC[TM] respectively represent the relationships between the elapsed time tEL and the output-voltage difference VDIF for the cases where the 6-ohm simple resistor, the 12.3-ohm simple resistor, the 240-ohm simple resistor, and the 6-ohm thermistor are used as resistive element 120.
  • dotted line GD[6], dashed line GD[12.3], dashed-dotted line GD[240], solid line GD[TM] respectively represent the relationships between the elapsed time tEL and heating value Q120 for the cases where the 6-ohm simple resistor, the 12.3-ohm simple resistor, the 240-ohm simple resistor, and the 6-ohm thermistor are used as resistive element 120.
  • the voltage-balancing time is approximately 10 units time for the case where 6-ohm simple resistor is used as resistive element 120.
  • the corresponding voltage-balancing time for the 12.3-ohm simple resistor is approximately 22 units time, and that for the 6-ohm thermistor is approximately 6 units time.
  • the voltage-balancing time for the case where 240-ohm simple resistor is used as resistive element 120 is approximately 432 unit time.
  • the maximum value of the heating value Q120 is approximately 28 W (watts) for the case where 6-ohm simple resistor is used as resistive element 120.
  • the corresponding value for the 12.3-ohm simple resistor is approximately 9 W, and that for 6-ohm thermistor is also approximately 3 W.
  • the maximum value of the heating value Q120 for the case where 240-ohm simple resistor is used as resistive element 120 is not larger than 1 W.
  • the use of a simple resistor as resistive element 120 increases the maximum heating value of resistive element 120 with the square of the output voltage difference VDIF, but hardly changes the time needed for the voltage-non-uniformity correction (i.e., the voltage-balancing time) almost the same even if the degree of the non-uniformity is decreased (e.g., even if the degree of the non-uniformity is decreased from 26 V down to 13 V).
  • the increase in the maximum amount of generated heat increases the maximum rating of, the physical size of, and the cost for resistive element 120.
  • 6-ohm thermistor leaves little difference between the maximum amounts of heat generated by resistive element 120 in the first and the second simulations, but cuts the voltage-balancing time in the second simulation into a quarter of its counterpart in the first simulation.
  • a PTC thermistor such as the 6-ohm thermistor
  • the maximum heating value of resistive element 120 can be kept down to a predetermined value or even smaller basically irrespective of the increase or the decrease in the output voltage difference VDIF.
  • the time needed for the voltage-non-uniformity correction is reduced by an amount corresponding to the reduction in the degree of non-uniformity.
  • the maximum amount of generated heat must not be larger than a limit amount (e.g., 5 W)
  • the use of a PTC thermistor as resistive element 120 can shorten the voltage-balancing time from the case where a simple resistor is used as resistive element 120 (see, for instance, GA[240] and GA[TM] in Fig. 20A and GB[240] and GB[TM] in Fig. 20B).
  • a PTC thermistor as resistive element 20[i] is particularly effective for a system where the occurrence of the output-voltage non-uniformity of the battery units is unpredictable and for a system where only a part of the battery units is replaced in the battery-unit replacement.
  • the use of a PTC thermistor as resistive element 20[i] is particularly effective when a new battery unit attached to apparatus AP (see Fig. 3) in battery-unit replacement is in the 40% to 60% capacity state. To put it differently, if a battery unit is replaced with a new one in battery-unit replacement, the voltage difference between each of those battery units not changed and the new battery unit attached to apparatus AP in the replacement has to be kept as small as possible.
  • the battery unit of 40% to 60% capacity state means a battery unit whose actual reserve capacity is 40% to 60% of the rated reserve capacity.
  • Parallel-connection circuit 5 and the battery system described above are provided with both circuits 20[i] and 30[i]. However, parallel-connection circuit 5 and the battery system may be provided only with circuit 20[i], or alternatively may be provided only with circuit 30[i].
  • each FET is an n-channel-type FET.
  • Each FET may be a p-channel-type FET.
  • controller 1 functions bath as a controller for the charging to control the states of continuity of FET 21[i] and as a controller for the discharging to control the states of continuity of FET 31[i].
  • Some of the applications of the invention are electrically-driven vehicles (including vehicles of a single wheel, two wheels, three wheels, four wheels, or more wheels), power tools, and electronic devices (including PCs, mobile phones, PDAs, etc.).

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  • Charge And Discharge Circuits For Batteries Or The Like (AREA)

Abstract

Une première ligne est électriquement couplée à une pluralité de batteries montées en parallèle, qui peuvent se connecter au circuit de mise en œuvre des batteries en parallèle. La première ligne est configurée pour fournir à la pluralité de batteries le courant de charge à partir d'une source d'alimentation électrique pouvant se connecter électriquement au circuit de mise en œuvre des batteries en parallèle. La première ligne connectant en parallèle les batteries de la pluralité de batteries comprend une pluralité de circuits anti-reflux de charge. Tous ces circuits anti-reflux sont configurés pour permettre au courant de charge de passer de la première ligne à une ligne correspondante de batteries, mais aussi pour empêcher le courant inverse de passer de la batterie à la première ligne.
PCT/JP2011/004481 2010-08-06 2011-08-06 Circuit de mise en oeuvre de batteries en parallèle, et système de batteries Ceased WO2012017697A1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
JP2010177257 2010-08-06
JP2010-177257 2010-08-06
JP2010228089A JP2013153545A (ja) 2010-08-06 2010-10-08 電池並列処理回路及び電池システム
JP2010-228089 2010-10-08

Publications (1)

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WO2012017697A1 true WO2012017697A1 (fr) 2012-02-09

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JP (1) JP2013153545A (fr)
WO (1) WO2012017697A1 (fr)

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EP2819267A3 (fr) * 2013-06-21 2015-04-15 Makita Corporation Unité de batterie
EP3764453A4 (fr) * 2018-04-19 2021-05-05 ZTE Corporation Dispositif de gestion de batterie et terminal mobile
WO2023007424A1 (fr) 2021-07-29 2023-02-02 H55 Sa Circuit et système pour le couplage d'une pluralité de blocs-batteries à un dispositif de commande de moteur dans un aéronef hybride électrique
TWI848307B (zh) * 2022-02-25 2024-07-11 大陸商昂寶電子（上海）有限公司 用於電荷泵的過流檢測電路
WO2024186251A1 (fr) * 2023-03-06 2024-09-12 Blixt Tech Ab Système de couplage électrique
EP4481987A3 (fr) * 2023-06-22 2025-04-16 Kubota Corporation Machine de travail électrique, procédé d'activation de machine de travail électrique et procédé de charge de machine de travail électrique

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JP6307992B2 (ja) * 2014-04-03 2018-04-11 株式会社デンソー 電源装置
JP2020031486A (ja) * 2018-08-22 2020-02-27 株式会社マキタ 電圧供給装置
JP7500680B2 (ja) * 2022-10-13 2024-06-17 ソフトバンク株式会社 システム
JP7756882B2 (ja) * 2023-10-11 2025-10-21 ソフトバンク株式会社 システム
JP2025073801A (ja) * 2023-10-27 2025-05-13 オムロン株式会社 蓄電装置、蓄電システム、制御方法及びプログラム

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Cited By (9)

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EP2819267A3 (fr) * 2013-06-21 2015-04-15 Makita Corporation Unité de batterie
US9490506B2 (en) 2013-06-21 2016-11-08 Makita Corporation Battery unit
EP3764453A4 (fr) * 2018-04-19 2021-05-05 ZTE Corporation Dispositif de gestion de batterie et terminal mobile
US11522369B2 (en) 2018-04-19 2022-12-06 Zte Corporation Battery management device and mobile terminal
WO2023007424A1 (fr) 2021-07-29 2023-02-02 H55 Sa Circuit et système pour le couplage d'une pluralité de blocs-batteries à un dispositif de commande de moteur dans un aéronef hybride électrique
US11962147B2 (en) 2021-07-29 2024-04-16 H55 Sa Circuit and system for coupling battery packs to motor controller in electric or hybrid aircraft
TWI848307B (zh) * 2022-02-25 2024-07-11 大陸商昂寶電子（上海）有限公司 用於電荷泵的過流檢測電路
WO2024186251A1 (fr) * 2023-03-06 2024-09-12 Blixt Tech Ab Système de couplage électrique
EP4481987A3 (fr) * 2023-06-22 2025-04-16 Kubota Corporation Machine de travail électrique, procédé d'activation de machine de travail électrique et procédé de charge de machine de travail électrique

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