JP2008176967A - In-vehicle battery discharge device - Google Patents

Abstract

The present invention relates to a discharge device that is mounted on an electric vehicle, a hybrid vehicle, or the like and that completely discharges an in-vehicle battery having a relatively high terminal voltage as a driving power source for a motor, and makes it easy to handle the in-vehicle battery. In addition, the discharge process is executed safely and quickly so that the memory effect can be recovered.
A discharge device for discharging an in-vehicle battery includes a discharge unit that controls a discharge current of the in-vehicle battery, and a connection between the discharge unit and the in-vehicle battery in the same polarity direction as the in-vehicle battery. A bias power supply unit that can flow a discharge current to zero V and a control unit that controls the discharge unit are provided.
[Selection] Figure 1

Description

  The present invention relates to an in-vehicle battery discharge device for safely and quickly discharging an in-vehicle battery mounted in an electric vehicle having a traveling drive source configured only with a motor, a hybrid vehicle having a traveling drive source composed of a motor and a gasoline engine, or the like. .

In-vehicle batteries mounted on ordinary automobiles have a terminal voltage of about 12 V or 24 V. However, in-vehicle batteries used as a driving power source for motors of electric vehicles and hybrid vehicles include a plurality of single cells connected in series. A secondary battery that is charged and used so as to have a terminal voltage of about 100 V is generally used, and for example, a nickel hydride battery or the like is known. When an electric vehicle or a hybrid vehicle is discarded, or when an in-vehicle battery is replaced and an old in-vehicle battery is discarded, it is desired to discharge the terminal voltage of the in-vehicle battery so that it is ideally 0V. For this purpose, a structure has been proposed in which a discharge resistor and a switch are incorporated in the battery case, the switch is operated to connect the resistor between the battery terminals, and the discharge is performed through the resistor. (For example, refer to Patent Document 1). In addition, a means for determining the lifetime based on the inter-terminal voltage, charging / discharging current, and temperature in the charging / discharging process of the secondary battery has been proposed (see, for example, Patent Document 2).
JP 2004-319304 A JP 2002-75461 A

  In-vehicle batteries in electric vehicles and hybrid vehicles that are used with terminal voltage charged to several hundred volts are discarded in the on-board state, or when replacing old in-vehicle batteries, electric shock accidents or shredding by a shredder In order to prevent an explosion accident at the time, it is ideal that the residual energy is zero, that is, the terminal voltage is 0V. However, when a discharge resistor is connected between the terminals of the battery as in the conventional example, the discharge resistance is set to a low resistance such as 0Ω. In addition, the protective means such as internal overcurrent protection operates to stop the discharge. Therefore, the resistance for discharge is selected to have a resistance value that does not cause the initial discharge current to be excessive, and there is a problem that the time until the discharge is completed becomes long. Also, if the internal resistance of the in-vehicle battery is not zero, for example, if it is 1Ω between the terminals, the terminal voltage of the in-vehicle battery will be 50 V corresponding to the voltage drop due to the internal resistance when discharged with a discharge current of 50A. There is also a problem that it is difficult to set the remaining terminal voltage to 0 V in a short time.

  Further, if the on-vehicle battery is, for example, a nickel metal hydride battery, it is necessary to perform a complete discharge process in order to recover the memory effect in which the chargeable capacity is reduced by repeated charging and discharging. Also in this case, there is a problem that it is difficult to complete discharge within a relatively short time only by connecting a resistor or the like between the terminals. Moreover, when performing discharge processing of a vehicle-mounted battery, in order to improve workability | operativity including the operation | work, it is requested | required that processing time should be estimated. It is also desired to determine whether or not the vehicle battery can be used in the future.

  The present invention solves the above-mentioned problems of the conventional example and makes it possible to provide the desired items. In disposing or replacing the battery, the vehicle battery can be completely discharged safely and promptly. Objective.

  The in-vehicle battery discharge device of the present invention controls a bias power source connected to the same polarity direction as the in-vehicle battery, and controls the discharge current of the in-vehicle battery via the bias power source, thereby reducing the terminal voltage of the in-vehicle battery to zero or minus. A discharge unit that discharges to a polarity and a control unit that controls a discharge current of the discharge unit are provided.

  In addition, the bias power supply unit is based on measuring means for measuring the internal resistance of the in-vehicle battery based on changes in the terminal voltage and the discharge current of the in-vehicle battery, and the internal resistance and discharge current of the in-vehicle battery measured by the measuring means. A configuration for controlling the bias power supply voltage to reduce or cancel the voltage drop can be provided.

  In addition, the discharge unit can be configured to discharge the vehicle-mounted battery through a bias power source to a range where the vehicle-mounted battery is not reversed by the control of the control unit to restore the memory effect of the vehicle-mounted battery.

  The communication unit includes a communication unit that receives voltage detection data from the battery communication unit that transmits the voltage detection data of the in-vehicle battery, and the control unit includes a range in which the in-vehicle battery does not reverse polarity based on the voltage detection data received by the communication unit. It is possible to provide a configuration in which the vehicle-mounted battery is discharged by the discharging unit via the bias power supply unit until the memory effect of the vehicle-mounted battery is restored.

  Further, an internal resistance measuring unit for measuring the internal resistance of the in-vehicle battery is provided based on a change in the terminal voltage with respect to a change in the discharge current of the in-vehicle battery, and the control unit has an internal resistance of the in-vehicle battery measured by the internal resistance measuring unit. The bias power supply unit can be controlled so as to reduce or cancel the voltage drop of the product of the current and the discharge current.

  In addition, the control unit measures the change in the internal resistance due to the discharge of the in-vehicle battery by the discharge unit, calculates the remaining capacity based on the characteristics of the in-vehicle battery from the change rate of the internal resistance, and the remaining capacity falls below the threshold value. When it falls, the means which determines with the use lifetime of a vehicle-mounted battery can be provided.

  In addition, the control unit measures a change in the internal resistance accompanying the discharge of the in-vehicle battery by the discharge unit, obtains a remaining capacity based on the characteristics of the internal resistance change and the capacity of the in-vehicle battery, and the remaining capacity is determined as a life determination threshold value. Means for determining the life expectancy of the in-vehicle battery can be provided from the number of charge / discharge cycles until it decreases below.

  In addition, the control unit measures the change in the internal resistance accompanying the discharge of the on-vehicle battery by the discharge unit, obtains the remaining capacity based on the characteristics of the change rate of the internal resistance and the capacity, and discharge characteristics corresponding to the remaining capacity. Based on the above, it is possible to provide means for obtaining the discharge time of the in-vehicle battery.

  In addition, the control unit measures the change in the internal resistance accompanying the discharge of the on-vehicle battery by the discharge unit, obtains the remaining capacity based on the characteristics of the change rate of the internal resistance and the capacity, and discharge characteristics corresponding to the remaining capacity. And means for obtaining the discharge end time based on the elapsed time from the start of discharge.

  Moreover, the said discharge part can be made into the alternating current regenerative discharge part which converts the discharge current through the bias power supply part of a vehicle-mounted battery into an alternating current, and sends it out to an alternating current power supply.

  The discharge part and the bias power supply make it easy to discharge until the terminal voltage of the in-vehicle battery reaches 0V, and it is possible to improve the safety of the in-vehicle battery when it is disused or replaced, and improve safety. It becomes possible to recover the memory effect of the vehicle battery at the time.

  Referring to FIG. 1, the battery discharge device of the present invention controls the bias power supply unit 5 connected in the same polarity direction as the vehicle-mounted battery 2, and controls the discharge current of the vehicle-mounted battery 2 via the bias power supply unit 5. A discharge unit 4 for discharging the terminal voltage of the battery 2 to zero or negative polarity; and a control unit 3 for controlling the discharge current of the discharge unit 4; Between the discharge part 4 and the vehicle-mounted battery 2, the bias power supply 5 connected to the vehicle-mounted vehicle battery 2 in the same polarity direction is provided.

  FIG. 1 is an explanatory diagram of Embodiment 1 of the present invention, in which 1 is a discharge device, 2 is an in-vehicle battery, 3 is a control unit, 4 is a discharge unit, 5 is a bias power supply unit, 8 is a battery case, and 9 is a battery. Indicates the protection part. The in-vehicle battery 2 is a motor driving power source mounted on an electric vehicle or a hybrid vehicle, and the terminal voltage is generally about 200V to 300V, and there is a configuration in which the voltage is further increased. In addition, a battery protection unit 9 such as a safety plug is provided in the battery case 8 that accommodates the in-vehicle battery 2 and is generally provided not only on the terminal side but also in the middle position of the serially connected cells.

  The discharge device 1 includes a control unit 3 including a processor, the discharge unit 4 in which setting control of discharge current and the like is performed by the control unit 3, and the same polarity as the polarity of the in-vehicle battery 2 to be discharged, that is, the in-vehicle battery. And a bias power supply unit 5 having a polarity to be added to the terminal voltage of 2. The bias power supply unit 5 is configured to have a voltage that compensates for an internal voltage drop due to an internal resistance when the vehicle battery 2 is discharged and has a current capacity that allows the discharge current of the vehicle battery 2 to flow. It is possible to apply a configuration in which voltage and current can be set depending on the number of connections, a switching power supply device in which voltage and current setting control is possible, and the like. It is possible to compensate the internal voltage drop of the in-vehicle battery 2 by the bias power supply unit 5 and discharge the terminal voltage of the in-vehicle battery 2 to be 0V. For example, it is easy to recover the memory effect of the applied alkaline hydrogen battery so that it can be used as a charge capacity close to the initial state.

  Further, the control unit 3 sets a discharge mode such as constant current discharge, a discharge current value, a discharge operation time, a discharge end voltage, and the like in the discharge unit 4 in accordance with the type of the in-vehicle battery 2 to be discharged. . In addition, although it is possible to provide display means for appropriately displaying various information including setting contents and the like, the discharge state when the discharge process is performed, the illustration is omitted. Further, when the in-vehicle battery 2 is connected to the discharge device 1 by means of a connector or the like and a start button or the like not shown is pressed, the discharge unit 4 is discharged via the in-vehicle battery 2 and the bias power source 5. Current will flow. In this case, for example, when the discharge mode is set to constant current discharge, the discharge current is set to 20A, the discharge time is set to 6 minutes, and the discharge end voltage is set to 0V, the discharge unit 4 is controlled in the constant current mode by the control unit 3 according to the set conditions. The in-vehicle battery 2 is discharged so that the discharge current is 20A.

  For example, the configuration shown in FIG. 2 can be applied to the discharge unit 4. In the figure, 10 is a discharge control circuit, 11 is a transistor, 12 is a comparator, 13 and 14 are terminals, and R1 and R2 are resistors. 1 is connected to the positive terminal side of the bias power supply unit 5 in FIG. 1, the terminal 14 is connected to the negative terminal side of the in-vehicle battery 2 in FIG. 1, and the discharge control circuit 10 is connected to FIG. Setting data from the control unit 3 is transferred. The discharge current flows through the transistor 11 and the resistor R1, and the comparator 12 compares the voltage Vr across the resistor R1 with the value corresponding to the set discharge current value from the discharge control circuit 10 to obtain the set discharge current value. Thus, the transistor 11 is controlled. Thereby, the vehicle-mounted battery 2 is discharged in a constant current discharge mode. As another discharge mode, it is possible to set a discharge mode in which the discharge current is changed in response to a change in the terminal voltage while detecting the terminal voltage of the in-vehicle battery 2.

  The end of the discharge of the in-vehicle battery 2 can be determined based on the discharge time or the terminal voltage of the in-vehicle battery 2. In the case of the above-described discharge time setting, the discharge ends when the set time elapses from the start of discharge. In a state where the relationship between the discharge current and the discharge time when the terminal voltage of the vehicle-mounted battery 2 becomes 0 V when the vehicle-mounted battery 2 is disconnected from 1 is known, the discharge can be terminated by setting the discharge time. In addition, since the terminal voltage of the vehicle-mounted battery 2 in the state where the vehicle-mounted battery 2 is connected to the discharge device 1 includes the voltage due to the internal resistance of the vehicle-mounted battery 2, the terminal voltage of the vehicle-mounted battery 2 in the connected state is 0V. Even if the in-vehicle battery 2 is disconnected from the discharge device 1, the terminal voltage of the in-vehicle battery 2 appears as a residual voltage other than 0V. The bias power supply unit 5 performs the action of discharging such residual voltage to 0V, and is configured to set the voltage and current of the bias power supply unit 5 in accordance with the type of the in-vehicle battery 2 and the terminal voltage. Can be applied.

  The transistor 12 applies a high capacity configuration capable of flowing a set maximum discharge current and a high breakdown voltage corresponding to the terminal voltage of the in-vehicle battery 2. For example, in order to allow a large current to flow, A plurality of transistors may be configured in parallel connection or in series connection. In addition, when it is set as a parallel connection structure, the balance control structure of the burden current of the parallel connection transistor already known can be applied. In the case of a serial connection configuration, a voltage sharing balance control configuration that has already been applied can be applied.

FIG. 3 is an explanatory diagram of Embodiment 2 of the present invention, where the same reference numerals as those in FIG. 1 denote the same name parts, 6 denotes an internal resistance measurement unit, and 7 denotes a current detection unit. The internal resistance measurement unit 6 can obtain the internal resistance r = BV / BI based on the terminal voltage BV of the in-vehicle battery 2 and the discharge current BI of the in-vehicle battery 2 detected by the current detection unit 7. In this case, the internal resistance r can be obtained by changing the discharge current and measuring the terminal voltage of the in-vehicle battery 2 thereby. For example, the terminal voltage at the time of changing the discharge current in _BI 1, BI ₂ is to become _BV 1, BV _2, be obtained internal resistance r as _{r = BV 1 -BV 2 / BI} 1 -BI 2 it can. When the internal resistance r is large, it indicates that the residual terminal voltage is high. Therefore, the voltage of the bias power supply unit 5 is increased or the discharge time is controlled to be long.

In order to change the discharge current, the control unit 3 controls the discharge unit 4 to change the discharge current from BI ₁ to BI ₂ , and the current detection unit 7 detects the discharge current at that time. Based on the change in the discharge current detected by the current detector 7 and the change in the terminal voltage of the in-vehicle battery 2, the internal resistance measuring unit 6 determines the internal resistance r of the in-vehicle battery 2 as described above. is calculated as _{r = BV 1 -BV 2 / BI} 1 -BI 2. Alternatively, the bias power supply unit 5 may be provided with means for superimposing an alternating voltage, and the internal resistance of the in-vehicle battery 2 may be measured by measuring the superimposed alternating voltage and the alternating current of the discharge current. .

  Such an internal resistance measuring means can be provided in the bias power supply unit 5 to automatically control the bias voltage to a value that cancels the voltage drop of the product of the internal resistance of the in-vehicle battery 2 and the discharge current. In this case, it is also possible to adopt a configuration in which the bias voltage is automatically set by a selection connection configuration of the number of connected bias power supply batteries or an output voltage control configuration of the switching power supply.

  FIG. 4 is an explanatory diagram of a third embodiment of the present invention, in which the same reference numerals as those in FIGS. 1 and 3 denote the same names, 21 is a communication unit, 22 is a battery ECU (Electronic Control Unit) (battery communication unit). Indicates. In addition, illustration of the current detection unit 7 in FIG. 3 is omitted. The battery ECU 22 has a function of transferring not only the terminal voltage of the in-vehicle battery 2 but also voltage detection data obtained by measuring the voltage of each unit battery to the communication unit 21. Various known means can be applied to this data transfer means. The communication unit 21 transfers the voltage detection data received from the battery ECU 22 to the control unit 3. When recovering the memory effect of the in-vehicle battery 2, the control unit 3 controls the discharge of the in-vehicle battery 2 by the discharge unit 4 within a range that does not reverse the polarity corresponding to the unit battery based on the voltage detection data. When discarding the in-vehicle battery 2, the terminal voltage of the in-vehicle battery 2 is discharged so that the terminal voltage becomes a low voltage such as 0V. Therefore, only the detection data of the terminal voltage is monitored and the discharge unit 4 It is only necessary to control the discharge process, and there is no particular problem even if a part of the unit batteries constituting the in-vehicle battery 2 is in a reversed state.

  FIG. 5 is an explanatory diagram of Embodiment 4 of the present invention, where the same reference numerals as those in FIGS. 1 and 3 indicate the same name portions, and 23 indicates the remaining measurement section. Can the remaining measurement unit 23 be used in the future in the discharge process for recovering the memory effect of the in-vehicle battery 2 based on the change in the internal resistance or the terminal voltage in the discharging process of the in-vehicle battery 2? In addition, it has a function of determining the remaining capacity when it can be used and estimating the time required for the discharge process, the end time of the discharge process, etc. The function of the remaining measurement unit 23 can also be realized by an arithmetic processing function of the control unit 3 including a computer.

  FIG. 6 is a characteristic curve diagram of an example of the increase rate and the recovery capacity ratio of the internal resistance of the in-vehicle battery. The horizontal axis indicates the square root of the cycle days, and the parentheses indicate the mileage conversion value of the vehicle. Curve a indicates the internal resistance increase rate characteristic, and b indicates the recovery capacity ratio by recovering the memory effect, and the ratio for a new product is 1 (100%). Although there are some differences depending on the type of the in-vehicle battery 2 and the like, the internal resistance increases as shown by the curve a and the recovery capacity ratio decreases as shown by the curve b due to repeated charging and discharging. For example, when the internal resistance increase rate is 1.04, the recovery capacity ratio is about 94%, and when the internal resistance increase rate is 1.2, the recovery capacity ratio is about 85%. Therefore, since this recovery capacity ratio indicates the ratio of the remaining usable capacity of the in-vehicle battery 2 to the initial 100%, the minimum remaining capacity for enabling use is set in advance, Can be determined that there is a need to replace the in-vehicle battery 2. Thus, since the lifetime of the vehicle-mounted battery 2 can be determined, the life expectancy due to the number of charge / discharge cycles can be estimated at the end of the discharge process.

  FIG. 7 is a characteristic curve diagram showing changes in the terminal voltage when the in-vehicle battery is discharged at a constant current. The horizontal axis represents time T, and the vertical axis represents terminal voltage V. A curve sv1 indicates a case where the remaining capacity is 100%, a curve sv2 indicates a remaining capacity of 90%, and a curve sv3 indicates a case where the remaining capacity is 80%. BV represents a bias voltage by the bias power supply unit 4. In the case of discharging from the start of discharge until the terminal voltage becomes 0 V by constant current discharge, the process ends at t1 when the remaining capacity is 100%, t2 when the remaining capacity is 90%, and t3 when the remaining capacity is 80%. In this case, the time required for the discharge of t1> t2> t3 is obtained. Therefore, when the discharge start time is t0, the time required for the discharge process can be obtained based on the recovery capacity ratio (remaining capacity ratio) shown in FIG. In the discharge process, the time required until the end of discharge can be obtained.

  Therefore, by holding the characteristic data as shown in FIGS. 6 and 7 for the in-vehicle battery 2 in the remaining measurement unit 23 or the control unit 3, the discharging process of the in-vehicle battery 2 by the discharge unit 4 and the bias power source unit 5 is performed. The required time and end time can be obtained. Similarly, as described above, it can be easily determined whether or not the in-vehicle battery 2 is usable. Such a determination result can be printed out by displaying it on a display panel (not shown) or by providing a print function.

  FIG. 8 is an explanatory diagram of Embodiment 5 of the present invention, in which the same reference numerals as those in FIG. 1 denote the same names, 4A denotes an AC regenerative discharge unit, and 30 denotes a commercial power line. In the fifth embodiment, the discharge unit 4 that performs the DC current discharge process is an AC regenerative discharge unit 4A that includes means for performing DC-AC conversion, and the DC power that discharges the in-vehicle battery 2 is converted to AC power. As a configuration for returning to the commercial power line 30 side, the power is effectively used. The means for performing the direct current to alternating current conversion can be applied with the configuration of a known DC to AC converter.

It is explanatory drawing of Example 1 of this invention. It is principal part explanatory drawing of a discharge part. It is explanatory drawing of Example 2 of this invention. It is explanatory drawing of Example 3 of this invention. It is explanatory drawing of Example 4 of this invention. It is a characteristic curve figure of an internal resistance increase rate and a recovery capacity ratio. It is a low current discharge characteristic curve figure. It is explanatory drawing of Example 5 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Discharge device 2 Car-mounted battery 3 Control part 4 Discharge part 5 Bias power supply part 6 Internal resistance measurement part 7 Current detection part 8 Battery case 9 Battery protection part

Claims (10)

A bias power supply connected in the same polarity direction as the vehicle battery,
A discharge unit for controlling the discharge current of the in-vehicle battery via the bias power source unit to discharge the terminal voltage of the in-vehicle battery to zero or negative polarity;
A vehicle-mounted battery discharge device comprising: a control unit that controls a discharge current of the discharge unit.   The bias power supply unit is configured to measure the internal resistance of the in-vehicle battery based on changes in the terminal voltage and the discharge current of the in-vehicle battery, and the internal resistance and discharge current of the in-vehicle battery measured by the measuring means. 2. The on-vehicle battery discharge device according to claim 1, further comprising a configuration for controlling the bias power supply voltage to reduce or cancel the voltage drop due to.   The discharge unit is configured to discharge the vehicle battery through the bias power source to a range in which the vehicle battery does not reverse by the control of the controller, and to recover the memory effect of the vehicle battery. The on-vehicle battery discharge device according to claim 1.   A communication unit that receives the voltage detection data from a battery communication unit that transmits voltage detection data of the in-vehicle battery; and the control unit is configured to transfer the in-vehicle battery based on the voltage detection data received by the communication unit. The in-vehicle configuration according to claim 1, further comprising: a control for recovering the memory effect of the in-vehicle battery by discharging the in-vehicle battery by the discharging unit through the bias power source unit to a non-existent range. Battery discharge device.   An internal resistance measurement unit that measures the internal resistance of the in-vehicle battery based on a change in terminal voltage with respect to a change in the discharge current of the in-vehicle battery is provided, and the control unit is configured to measure the internal resistance of the in-vehicle battery measured by the internal resistance measurement unit. The in-vehicle battery discharge device according to claim 1, further comprising a configuration for controlling the bias power supply unit so as to reduce or cancel a voltage drop of a product of a resistance and a discharge current.   The control unit measures a change in internal resistance accompanying the discharge of the in-vehicle battery by the discharge unit, calculates a remaining capacity based on a characteristic of the in-vehicle battery from a change rate of the internal resistance, and the remaining capacity is a threshold value 6. The on-vehicle battery discharge device according to claim 1, further comprising means for determining the service life of the on-vehicle battery when it drops below.   The control unit measures a change in internal resistance accompanying the discharge of the in-vehicle battery by the discharge unit, obtains a remaining capacity based on characteristics of the internal resistance change and capacity of the in-vehicle battery, and the remaining capacity determines the life 6. The on-vehicle battery discharge device according to any one of claims 1 to 5, further comprising means for determining the remaining life of the on-vehicle battery from the number of charge / discharge cycles until the value drops below a threshold value.   The control unit measures a change in internal resistance due to the discharge of the in-vehicle battery by the discharge unit, obtains a remaining capacity based on a characteristic of the change rate and capacity of the internal resistance, and discharges corresponding to the remaining capacity 6. The on-vehicle battery discharge device according to claim 1, further comprising means for obtaining a discharge time of the on-vehicle battery based on characteristics.   The control unit measures a change in internal resistance due to the discharge of the in-vehicle battery by the discharge unit, obtains a remaining capacity based on a characteristic of the change rate and capacity of the internal resistance, and discharges corresponding to the remaining capacity 6. The on-vehicle battery discharge device according to claim 1, further comprising means for obtaining a discharge end time based on the characteristics and the elapsed time from the start of discharge.   10. The AC regenerative discharge unit that converts the discharge current through the bias power supply unit of the in-vehicle battery into an AC current and sends the AC current to the AC power supply. The vehicle-mounted battery discharge device according to item.

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