KR20090081894A - Battery pack - Google Patents

Abstract

The present invention relates to a battery pack, and a technical problem to be solved is to provide a battery pack in which a thin and well bent solar cell and a secondary battery are used in combination, and the secondary battery is supplemented with electric power by the solar cell.

For this purpose solar cells; A secondary cell electrically connected to the solar cell; A charge / discharge switching element electrically connected to the high current path of the solar cell and the secondary cell; A switching element for solar cells electrically connected on a high current path between the solar cell and the secondary cell; And a protection circuit unit electrically connected to the solar cell switching element and the charge / discharge switching element, and outputting an electrical signal to the solar cell switching element and the charge / discharge switching element to turn on or off the solar cell switching element and the charge / discharge switching element. Disclosed is a battery pack consisting of.

Therefore, in the battery pack of the present invention, since the secondary battery is supplemented with electric power by the power of the solar cell, the capacity is increased and the use time is long.

Solar Cells, Organics, Plastics, Protection Circuits, Portable Electronics

Description

Battery pack {BATTERY PACK}

The present invention relates to a battery pack, and more particularly, to a battery pack using a combination of an organic plastic solar cell and a secondary battery.

Compact and lightweight portable electric / electronic devices such as cellular phones, notebook computers and camcorders are actively developed and produced. Therefore, portable electric / electronic devices have a built-in battery pack so that they can be operated even in a place where a separate power source is not provided. The battery pack has recently adopted a secondary battery capable of charging and discharging in consideration of economic aspects. In addition, secondary batteries are in the spotlight for hybrid car batteries that require high-density energy and high power, and are being researched and developed and produced.

Typical secondary batteries include nickel-cadmium (Ni-Cd) batteries, nickel-hydrogen (Ni-MH) batteries, lithium (Li) batteries, and lithium ion (Li-ion) batteries.

In particular, lithium ion batteries are about three times higher in operating voltage than nickel-cadmium batteries or nickel-hydrogen batteries, which are widely used as power sources for portable electronic equipment. In addition, it is widely used in view of high energy density per unit weight. The lithium ion battery uses a lithium oxide as a positive electrode active material and a carbon material as a negative electrode active material. In general, a battery is classified into a liquid electrolyte battery and a polymer electrolyte battery according to the type of electrolyte. A battery using a liquid electrolyte is called a lithium ion battery, and a battery using a polymer electrolyte is called a lithium polymer battery.

On the other hand, recently developed portable electronic products have a trend that the structure is developed in a very small and thin form. As small and thin portable electronic products increase, lithium ion batteries that power portable electronic products are also designed to be very small and thin. In addition, recent portable electronic products are designed in a curved shape to enhance the beauty when designing the appearance. In this case, the current lithium ion battery provides a structure that is curved to some extent to the structure. For example, a pouch type secondary battery is a typical example. However, in the case of portable electronic products, which are small, thin and have a large radius of curvature, the life of the lithium ion battery may be shortened as the shape of the lithium ion battery is changed into a curved shape. For example, in the case of a pouch type secondary battery, when the battery is bent too much, electrolyte may leak out of the battery, thereby shortening the life of the battery.

Therefore, there is a current need for a battery pack suitable for small and thin portable electronic products. To this end, a plurality of batteries may be combined to be used as a battery pack suitable for a structure of a portable electronic product, but in this case, a protection circuit for protecting a plurality of batteries needs to be charged and discharged, respectively, so the structure of the protection circuit becomes very complicated. Will occur.

In addition, battery packs that are too thin have a smaller capacity, and thus, a capacity shortage that cannot continuously supply power to portable electronic products occurs.

The technical problem of the present invention devised by the above necessity is to provide a battery pack in which a thin and well bent solar cell and a secondary battery are used in combination, and the secondary battery is supplemented with electric power by the solar cell.

In addition, another technical problem of the present invention is to provide a battery pack that prevents deterioration of a solar cell by preventing a current of a charger from flowing into the solar cell when a thin and well-cured solar cell and a secondary battery are used in combination.

In addition, another technical problem of the present invention is to provide a battery pack having a thin and well bent organic plastic solar cell and a protection circuit for efficiently charging and discharging a secondary battery.

Battery pack of the present invention for achieving the above technical problem is a solar cell; A secondary battery electrically connected to the solar cell; A charge / discharge switching element electrically connected to a large current path between the solar cell and the secondary battery; A solar cell switching element electrically connected on a high current path between the solar cell and the secondary cell; And turn on the solar cell switching element and the charge / discharge switching element by being electrically connected to the solar cell switching element and the charge / discharge switching element and outputting an electrical signal to the solar cell switching element and the charge / discharge switching element. Or it characterized in that it comprises a protection circuit to turn off.

In addition, the solar cell is formed of an organic plastic solar cell, the solar cell may generate power by absorbing the wavelength from visible light to infrared light.

In addition, on the high current path of the secondary battery and the solar cell, a diode having the positive electrode of the secondary battery forward may be connected to block the charging path from the secondary battery to the solar cell.

The protection circuit unit may turn on the solar cell selection switching element when the voltage on the high current path of the solar cell and the secondary battery is less than a specific threshold.

The protection circuit unit may include a voltage comparison unit electrically connected to a large current path of the secondary battery to detect a voltage of the secondary battery; A switching circuit unit electrically connected to the charge / discharge switching element and the solar cell switching element to increase a voltage; An overcurrent sensing circuit electrically connected to a large current path of the secondary battery and detecting an overcurrent of the secondary battery to turn off the charge / discharge switching element; A delay circuit unit electrically connected to the high current path of the secondary battery to set a delay time between a full charge state and a full discharge state; And a control logic unit electrically connected to the voltage comparing unit, the switching circuit unit, and the delay circuit unit, and outputting an on or off signal to the switching circuit according to a voltage state of the voltage comparing unit and a set delay time of the delay circuit unit. Can be.

The voltage comparison unit may be configured by applying a reference voltage to an operational amplifier, wherein the voltage comparison unit includes an overcharge detection comparator for detecting an overcharge state of the secondary battery, and a full charge detection unit for detecting a full charge state of the secondary battery. Comparators, a full discharge detection comparator for detecting the full discharge state of the secondary battery, and an over discharge detection comparator for detecting the over discharge state of the secondary battery can be formed.

The switching circuit unit may include a solar cell switching circuit electrically connected to each of the solar cell switching element and the charge / discharge switching element, a charge switching circuit, and a discharge switching circuit.

In the battery pack of the present invention, since the secondary battery is supplemented with electric power by the power of the solar cell, the capacity is increased and the use time is long.

In addition, the battery pack of the present invention prevents deterioration of the solar cell by preventing the current of the secondary battery charged by the charger from flowing into the solar cell when the solar cell and the secondary battery are used in combination.

In addition, the battery pack of the present invention operates very stably with a thin and well bent organic plastic solar cell and a protection circuit for efficiently charging and discharging a secondary battery.

The above effects are briefly described so as not to obscure the gist of the present invention, and in the detailed description of the present invention, the effects corresponding to the features of the present invention will be described in more detail.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following embodiments, the same reference numerals are used for the same components, and overlapping descriptions of the same components will not be possible.

1A is a block diagram of a battery pack according to an embodiment of the present invention. FIG. 1B is a block diagram showing the internal configuration of the protection circuit shown in FIG. 1A.

The battery pack 100 according to the exemplary embodiment of the present invention includes a solar cell 110, a secondary battery 120, a charge / discharge switching device 130, a switching device 140 for a solar cell, and a protection circuit unit 150. Is formed. In addition, the battery pack 100 further includes a positive terminal 11 and a negative terminal 12 so that the high current path 10 of the solar cell 110 and the secondary cell 120 can be connected to a charger or a load from the outside. Can be formed.

The solar cell 110 may be formed of the organic plastic solar cell 110 and may generate power by absorbing wavelengths from visible light to infrared light.

The secondary battery 120 has a large current path 10 for charging or discharging the secondary battery 120 is electrically connected to the solar cell 110 in parallel. In addition, the secondary battery 120 may be a rechargeable battery, a can type battery in which an electrode assembly as a power generation source is housed in a can, or a pouch type battery in which the electrode assembly as a power generation source is sealed with a pouch.

The charge / discharge switching element 130 is electrically connected to a large current path between the solar cell 110 and the secondary battery 120. In this embodiment, the charge / discharge switching element 130 is formed to include the charge switching element 131 and the discharge switching element 132. The charge / discharge switching element 130 may be formed of an electric element having a switching function such as a field effect transistor. For example, the charge switching device and the discharge switching device may be formed of a field effect transistor (NMOS) type, that is, an N-channel type field effect transistor. Can be. In addition, parasitic diodes 131a and 132a may be formed in each of the charging switching element 131 and the discharge switching element 132. The parasitic diode 131a formed in the charging switching element 131 may be a secondary battery 120. ) Discharges the flowing current, and the parasitic diode 132a formed in the discharge switching element 132 blocks the discharge current flowing when the secondary battery 120 is charged.

The solar cell switching element 140 is electrically connected on the large current path 10 between the solar cell 110 and the secondary cell 120. The solar cell switching element 140 may be formed of an electric element having a switching function such as a field effect transistor. For example, the switching element 140 for a solar cell may be formed of an NMOS type field effect transistor.

The protection circuit unit 150 is electrically connected to the large current path 10 of the solar cell switching element 140, the charge and discharge switching element 130, and the secondary battery 120.

In addition, the protection circuit unit 150 may include a voltage comparator 151, a control logic unit 152, a switching circuit unit 153, an overcurrent sensing circuit unit 154, and a delay circuit unit 155 therein.

The voltage comparing unit 151 may apply a reference voltage to a plurality of operational amplifiers to detect a specific voltage value. In this case, the voltage comparator 151 includes an overcharge detection comparator 151a for detecting an overcharge voltage, a comparator for full charge detection 151b for detecting a full charge voltage, a comparator for full discharge detection for detecting a full discharge voltage ( 151c and an overdischarge detection comparator 151d for detecting the overdischarge voltage. Accordingly, each of the comparators may detect the overcharge voltage, the full charge voltage, the full discharge voltage, and the over discharge voltage of the secondary battery 120, and output the detected signal to the control logic unit 152.

The control logic unit 152 outputs a signal to the switching circuit 153 according to the voltage output from the voltage comparing unit 151, that is, the overcharge state, the full charge state, the full discharge state, and the over discharge state of the secondary battery 120. The charging switching element 131, the discharge switching element 132, and the solar cell switching element 140 may be turned on or off. In addition, the control logic unit 152 is electrically connected to the delay circuit unit 155, and sends a signal to the switching circuit 153 when the full charge delay time and the full discharge delay time set by the delay circuit unit 155 are reached. The switching element 131 and the discharge switching element 132 may be turned off. For example, the control logic unit 152 sends a signal to the charging switching circuit 153b when a time corresponding to a specific value elapses while the secondary battery 120 is continuously charged. You can turn it off. In addition, the control logic unit 152 turns off the discharge switching device 132 by sending a signal to the discharge switching circuit 153c when a time corresponding to a specific value passes while the secondary battery 120 is continuously discharged. You can.

The switching circuit unit 153 may include a solar cell switching circuit 153a, a charge switching circuit 153b, and a discharge switching circuit 153c. In addition, the switching circuit unit 153 is electrically connected to the control logic unit 152 and the overcurrent sensing circuit unit 154. In addition, the switching circuit unit 153 is electrically connected to the solar cell switching element 140, the charge switching element 131, and the discharge switching element 132. Here, the solar cell switching circuit 153a is electrically connected to the solar cell switching element 140, the charge switching circuit 153b is electrically connected to the charge switching element 131, and the discharge switching circuit 153c is discharged. It is electrically connected to the switching element 132. The switching circuit unit 153 may be formed as an inverter circuit in which an N-channel and a P-channel are connected in parallel so as to boost the voltage so that the gate threshold voltage of the solar cell switching element 140 and the charge / discharge switching element 130 are matched. Can be.

The overcurrent detecting circuit unit 154 may be electrically connected to the large current path 10 of the secondary battery to detect the overcurrent. In this case, the overcurrent detecting circuit unit 154 may be electrically connected to the resistor 170 to detect the overcurrent. The overcurrent detection circuit unit 154 may turn off the charge / discharge switching device 130 by driving the charge switching circuit 153b and the discharge switching circuit 153c when the overcurrent is detected. In addition, the overcurrent detecting circuit unit 154 may be electrically connected to the delay circuit unit 155 connected to the positive electrode of the secondary battery 120 to detect the impedance of the secondary battery 120, and the secondary battery 120 may be detected with the detected impedance. ), The charge switching circuit 153b and the discharge switching circuit 153c may be signaled to turn off the charging switching element 131 and the discharge switching element 132.

The delay circuit unit 155 is electrically connected to the large current path 10 of the secondary battery. In addition, the delay circuit unit 155 is electrically connected by the high current path 10 of the secondary battery and the capacitor 180, and the delay circuit unit 155 may be fully charged and delayed according to the capacity of the capacitor 180. The delay time and the overcurrent delay time can be set. For example, when the capacity of the capacitor 180 is 0.047 0.0, the full charge delay time may be set to 20 seconds, the full discharge delay time may be set to 2 seconds, and the overcurrent delay time may be set to 0.2 seconds. In this case, the ratios of the full charge delay time, the overdischarge delay time, and the overcurrent delay time are set to 100: 10: 1, and the ratio may be set to vary according to the capacity of the capacitor 180.

In addition, the protection circuit unit 150 may be packaged into a single semiconductor chip in order to minimize the mounting area, and combined with the solar cell 110 and the secondary battery 120 in a unitary form of an electronic product (not shown) Can be mounted.

On the other hand, the diode 160 is connected on the large current path between the secondary battery 120 and the solar cell 110 with the anode of the secondary battery 110 in the forward direction. The diode 160 blocks the charging path of the solar cell 110. The diode 160 blocks the current flowing to the solar cell 110 when the secondary battery 120 is charged from the charger. ) Does not deteriorate.

The operation relationship of the battery pack 100 will be described by dividing the charging and discharging time. In the following description, the solar cell 110 is continuously irradiated with light, and thus the solar cell 110 will be described in a fully charged state.

[When charging the battery pack]

First, when the battery pack 100 is charged, when a charger (not shown) is connected to the positive terminal 11 and the negative terminal 12, the overcurrent detecting circuit unit 154 of the protection circuit unit 150 detects this. The control logic unit 152 turns on the charging switching element 131 by outputting a signal to the charging switching circuit 153b. Therefore, the charger (not shown) supplies the current to the secondary battery 120 to charge the secondary battery 120. Here, the current direction supplied from the charger (not shown) to the secondary battery 120 is a counterclockwise direction. Therefore, since the charging path is blocked by the diode 160, the solar cell 110 may be prevented from being charged by the current and may be charged only by light.

In addition, the secondary battery 120 may be fully charged when continuously charged by a charger (not shown). For example, when the voltage of the secondary battery 120 sensed by the full charge voltage comparator 151b is 4.0 V due to continuous charging, the control logic unit 152 may include a delay circuit unit ( After the time set in 155, the charge switching device 131 is turned off.

In addition, the secondary battery 120 may be overcharged when continuously charged. For example, there may occur a case where the voltage of the secondary battery 120 detected by the overcharge detection comparator 151a becomes 4.2V due to continuous charging, in which case the control logic unit 152 charges immediately. The switching element 131 is turned off to prevent charging of the secondary battery 120.

[Discharge of battery pack]

When the battery pack 100 is discharged, when a load (not shown) is connected to the positive terminal 11 and the negative terminal 120, the protection circuit unit 150 detects this and turns on the discharge switching element 132. . Therefore, the load (not shown) may be operated by receiving a current supplied from the secondary battery 120. Here, the current direction supplied to the load (not shown) is clockwise.

In addition, when the secondary battery 120 continuously supplies power to a load (not shown), the secondary battery 120 may be fully discharged. For example, when the voltage of the secondary battery 120 detected by the full discharge detecting comparator 151c becomes 3.2 V due to continuous discharge, the control logic unit 152 after the time set by the delay circuit unit 155 has passed. Transmits a signal to the discharge switching circuit 153c to turn off the discharge switching element 132, and as a result, the secondary battery 120 is prohibited from being discharged.

In addition, the secondary battery 120 continuously maintains a full discharge state and may be over discharged by power consumed by the protection circuit unit 150. For example, when the voltage detected by the over-discharge detection comparator 151d becomes 3.0 V due to over-discharge, the control logic unit 152 sends a signal to the switching circuit 153a for the solar cell and the switching element for the solar cell. Turn on 140. Accordingly, the secondary battery 120 is electrically connected to the solar cell 110, and the solar cell 110 supplies power to the secondary battery 120. Therefore, since the load (not shown) is supplied with power from the secondary battery 120 and the solar cell 110, the load (not shown) may be supplied for a longer time than when the power is supplied from the single secondary battery 120. .

FIG. 2 is an exploded plan view of a portable terminal and a battery pack as an application example of the battery pack shown in FIG. 1.

As shown in FIG. 2, the battery pack 100 is inserted into the battery accommodation space 200a of the portable terminal 200 to supply power to the portable terminal 200. Here, the organic plastic solar cell 110 is mounted on the outer portion of the battery pack 200 and is charged by light transmitted through the transparent cover of the battery pack. In addition, a pouch type secondary battery (not shown) is mounted inside the organic plastic solar cell 110. The portable terminal 200 is mainly supplied with power of a secondary battery (not shown), and when the voltage of the secondary battery is below a certain threshold value, for example, when the voltage falls below a voltage of less than 3.0V, the protection circuit unit ( 150 operates a solar cell switching element (not shown) to supply power from the solar cell 110 to the secondary battery. Therefore, the secondary battery is charged by the electric power supplied from the solar cell 110, thereby increasing the time for supplying power.

In addition, in the battery pack 100 of the present invention, the solar cell 110 and the secondary battery are used in a mixed state, and thus the power supply time is long, and a protection circuit (not shown) of the battery pack 100 is the solar cell 110. ) To operate the battery pack 100 stably by efficiently charging and discharging the secondary battery.

1A is a block diagram of a battery pack according to an embodiment of the present invention.

FIG. 1B is a block diagram showing the internal configuration of the protection circuit shown in FIG. 1A.

FIG. 2 is an exploded plan view of a portable terminal and a battery pack as an application example of the battery pack shown in FIG. 1.

<Explanation of symbols for the main parts of the drawings>

11; Positive terminal 12; Negative terminal

100; Battery pack 110; Solar cell

120; Secondary battery 130; Charge / discharge switching element

131; Charge switching element 132; Discharge switching element

131a, 132a; Parasitic diode 140; Switching element for solar cell

150; Protective circuit section 151; Voltage comparison part

151a; Overcharge detection comparator 151b; Full charge detection comparator

151c; Comparator for full discharge detection 151d; Comparator for Overdischarge Detection

152; Control logic section 153; Switching circuit

153a; Switching circuit 153b for solar cells; Charge switching circuit

153c; Discharge switching circuit 154; Over Current Detection Circuit

155; Delay circuit section 160; diode

170; Register 180; Capacitor

200; Handheld terminal

Claims (7)

Solar cells; A secondary battery electrically connected to the solar cell; A charge / discharge switching element electrically connected to a large current path between the solar cell and the secondary battery; A solar cell switching element electrically connected on a high current path between the solar cell and the secondary cell; And Electrically connected to the solar cell switching element and the charge / discharge switching element, and output an electrical signal to the solar cell switching element and the charge / discharge switching element to turn on the solar cell switching element and the charge / discharge switching element or A battery pack comprising a protection circuit to turn off. The method of claim 1, The solar cell is formed of an organic plastic solar cell, the solar cell is a battery pack, characterized in that to generate power by absorbing the wavelength from visible light to infrared light. The method of claim 1, The battery pack, characterized in that the charge path from the secondary battery to the solar cell is cut off by connecting a diode in the forward direction of the secondary battery on the large current path of the secondary battery and the solar cell. The method of claim 1, The protection circuit unit turns on the solar cell selection switching element when the voltage on the high current path of the solar cell and the secondary battery is less than a specific threshold value. The method of claim 1, The protection circuit part A voltage comparing unit electrically connected to a large current path of the secondary battery to detect a voltage of the secondary battery; A switching circuit unit electrically connected to the charge / discharge switching element and the solar cell switching element to increase a voltage; An overcurrent sensing circuit electrically connected to a large current path of the secondary battery and detecting an overcurrent of the secondary battery to turn off the charge / discharge switching element; A delay circuit unit electrically connected to the high current path of the secondary battery to set a delay time between a full charge state and a full discharge state; And And a control logic unit electrically connected to the voltage comparing unit, the switching circuit unit, and the delay circuit unit, and outputting an on or off signal to the switching circuit according to a voltage state of the voltage comparing unit and a set delay time of the delay circuit unit. A battery pack, characterized in that. The method of claim 5, wherein The voltage comparison unit is configured by applying a reference voltage to the operational amplifier, the voltage comparison unit is an overcharge detection comparator for detecting the overcharge state of the secondary battery, a full charge detection comparator for detecting the full charge state of the secondary battery, And a full discharge detection comparator for detecting a full discharge state of the secondary battery, and an over discharge detection comparator for detecting an over discharge state of the secondary battery. The method of claim 5, wherein And the switching circuit unit comprises a solar cell switching circuit electrically connected to each of the solar cell switching element and the charge / discharge switching element, a charge switching circuit, and a discharge switching circuit.

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