Battery pack and battery

Abstract

To provide a battery pack and the like, which can improve safety by suppressing progress of a failure, caused by leakage of an electrolyte, by a simple constitution.SOLUTION: A battery pack 100 comprises: a battery cell 200 into which an electrolyte is encapsulated; a case part 101 within which the plurality of battery cells 200 are housed; an electrolyte absorption material 300 which is provided within the case part 101 and which absorbs the electrolyte leaked from the battery cell 200; and a liquid-crystal light control film 130 and a leaked liquid detection terminal 120, which serve as a current-carrying part in the case of liquid leaked, electrically connected to the battery cell 200 with no leaked electrolyte, via the electrolyte absorption material 300 absorbing the electrolyte.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a battery pack and a battery. [Background technology]

[0002] A known battery pack is connected to a main device or a charger for discharging or charging and includes a battery cell, a leakage detection means for detecting leakage of electrolyte from the battery cell, a current interruption means for electrically disconnecting the current line between the battery cell and an external terminal when leakage occurs in the battery cell, and a warning means for notifying the outside of leakage of electrolyte from the battery cell (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-084996 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the battery pack disclosed in Patent Document 1, the warning means that notifies the outside of the occurrence of electrolyte leakage in a battery cell is driven by power supplied from the battery cell in which the electrolyte leakage occurred. Therefore, even if only temporarily, it is necessary to continue discharging from the battery cell in which the electrolyte leakage occurred, and during this time, there is a possibility that the malfunction caused by the electrolyte leakage may progress.

[0005] The present disclosure has been made to solve these problems, and its purpose is to provide a battery pack and a battery that can suppress the progression of failures due to electrolyte leakage with a simple configuration and improve safety. [Means for solving the problem]

[0006] The battery pack according to the present disclosure includes battery cells having electrolyte sealed therein, a case portion that houses a plurality of the battery cells, an electrolyte absorbent material provided inside the case portion that absorbs the electrolyte leaked from the battery cells, and a leakage current-carrying portion that is electrically connected to the battery cells from which the electrolyte is not leaking via the electrolyte absorbent material that has absorbed the electrolyte.

[0007] Alternatively, a battery pack according to the present disclosure includes battery cells having an electrolyte sealed therein, a case portion that houses a plurality of the battery cells, a pair of terminals that are exposed to the outside of the case portion and are electrically connected to the positive and negative electrodes of the battery cells, respectively, and a conductive polymer provided inside the case portion between the positive electrode and the terminal and / or between the negative electrode and the terminal, wherein the conductive polymer dissolves upon contact with the electrolyte leaked from the battery cells, thereby cutting either or both of the electrical connection between the positive electrode of the battery cell from which the electrolyte has leaked and the terminal and the electrical connection between the negative electrode of the battery cell from which the electrolyte has leaked and the terminal.

[0008] The battery according to the present disclosure is a battery having an electrolyte sealed therein, and includes a positive electrode containing a positive electrode active material, a negative electrode containing a negative electrode active material, a separator and the electrolyte arranged between the positive electrode and the negative electrode, a positive electrode-side terminal electrically connected to the positive electrode, a negative electrode-side terminal electrically connected to the negative electrode, and a conductive polymer provided on one or both of the positive electrode-side terminal and the negative electrode-side terminal, wherein the conductive polymer dissolves upon contact with the electrolyte and cuts off one or both of the electrical connection between the positive electrode and the outermost end of the positive electrode-side terminal and the electrical connection between the negative electrode and the outermost end of the negative electrode-side terminal. [Effects of the Invention]

[0009] The battery pack and battery according to the present disclosure have the advantage of being able to suppress the progression of failures caused by electrolyte leakage with a simple configuration. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a diagram schematically illustrating a configuration of a battery pack according to a first embodiment. [Figure 2] 1 is a circuit diagram of a main part of a battery pack according to a first embodiment. [Figure 3] FIG. 3 is a circuit diagram equivalent to the circuit shown in FIG. 2. [Figure 4] 1 is a cross-sectional view schematically showing the configuration of a battery cell (battery) included in a battery pack according to a first embodiment. [Figure 5] 10 is a circuit diagram of a main part of a modified example of the battery pack according to the first embodiment. FIG. [Figure 6] FIG. 6 is a circuit diagram equivalent to the circuit shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0011] Embodiments of a battery pack and a battery according to the present disclosure will be described with reference to the accompanying drawings. In each drawing, identical or corresponding parts are designated by the same reference numerals, and redundant descriptions will be appropriately simplified or omitted. For convenience, the following description may express the positional relationship of each structure based on the illustrated state. Note that the present disclosure is not limited to the following embodiments, and any combination of the embodiments, any modification of any component of each embodiment, or any omission of any component of each embodiment are possible within the scope of the present disclosure.

[0012] Embodiment 1 A first embodiment of the present disclosure will be described with reference to Figs. 1 to 6. Fig. 1 is a diagram schematically illustrating the configuration of a battery pack. Fig. 2 is a circuit diagram of a main part of the battery pack. Fig. 3 is a circuit diagram equivalent to the circuit shown in Fig. 2. Fig. 4 is a cross-sectional view schematically illustrating the configuration of a battery cell (battery) included in the battery pack. Fig. 5 is a circuit diagram of a main part of a modified example of the battery pack. Fig. 6 is a circuit diagram equivalent to the circuit shown in Fig. 5.

[0013] As shown in Fig. 1, a battery pack 100 according to this embodiment includes a case 101. The case 101 is a member that forms the outer shell of the battery pack 100. In the illustrated example, the case 101 is provided with a handle 102. The handle 102 is a part that a user can grasp when carrying the battery pack 100 or attaching the battery pack 100 to an electrical device, a charger, or the like.

[0014] The battery pack 100 includes one or more battery cells 200. In the configuration example described here, the battery pack 100 includes a plurality of battery cells 200. FIG. 1 shows an example in which the battery pack 100 includes four battery cells 200. One or more battery cells 200 are housed inside a case 101. Each battery cell 200 is a single cell of a secondary battery. As will be described later, an electrolyte is sealed inside each battery cell 200. Each battery cell 200 is also provided with a positive terminal 201 and a negative terminal 202.

[0015] The battery pack 100 includes a pair of charging / discharging terminals 110. The pair of charging / discharging terminals 110 are exposed to the outside of the case portion 101. One of the pair of charging / discharging terminals 110 is a positive terminal. The other of the pair of charging / discharging terminals 110 is a negative terminal. The positive charging / discharging terminal 110 is electrically connected to the positive terminal 201 of each battery cell 200 in the case portion 101. The negative charging / discharging terminal 110 is electrically connected to the negative terminal 202 of each battery cell 200 in the case portion 101.

[0016] 1, the battery cells 200 in the case 101 are connected in parallel. However, the connection of the battery cells 200 is not limited to parallel, and may be series connection or a combination of series and parallel connection.

[0017] The battery pack 100 according to this embodiment further includes an electrolyte solution absorber 300. The electrolyte solution absorber 300 is provided inside the case 101. If the electrolyte solution sealed in the battery cell 200 leaks, the electrolyte solution absorber 300 can absorb the leaked electrolyte solution. The electrolyte solution absorber 300 may be made of any substance, material, or the like, as long as it has the property of being able to absorb the electrolyte solution used in the battery cell 200.

[0018] The electrolyte solution absorbent material 300 may be placed anywhere inside the case 101 as long as it is capable of absorbing the electrolyte leaked from the battery cells 200. However, in order to reliably and efficiently absorb the electrolyte leaked from the battery cells 200, it is preferable to place the electrolyte solution absorbent material 300 as close to the battery cells 200 as possible. For this reason, in the illustrated example, the electrolyte solution absorbent material 300 is wrapped around the outer periphery of the battery cells 200.

[0019] Furthermore, in order to fix the position of the battery cell 200 inside the case part 101, a holder may be provided inside the case part 101, and the battery cell 200 may be held by the holder. In such a case, the electrolyte absorbent material 300 may be provided on the holder. This also allows the electrolyte absorbent material 300 to be positioned close to the battery cell 200.

[0020] The electrolyte solution absorbent 300 is an insulator. That is, the electrolyte solution absorbent 300 is non-conductive when it has not absorbed any electrolyte solution. On the other hand, the electrolyte solution absorbent 300 becomes conductive when it has absorbed a certain amount or more of electrolyte solution.

[0021] The battery pack 100 according to this embodiment further includes a leakage current-carrying unit. The leakage current-carrying unit is electrically connected to the positive terminal 201 and the negative terminal 202 of each battery cell 200. An electrolyte absorber 300 is inserted midway along the conductor connecting the leakage current-carrying unit to each battery cell 200. In the illustrated example, the battery pack 100 includes a leakage detection terminal 120 and a liquid crystal light control film 130 as the leakage current-carrying unit.

[0022] In the configuration example described here, the conductor connected to the negative terminal 202 of each battery cell 200 is directly connected to the liquid crystal light control film 130. On the other hand, the conductor connected to the positive terminal 201 of each battery cell 200 is connected to the liquid crystal light control film 130 with the electrolyte solution absorber 300 sandwiched in the middle.

[0023] Furthermore, the pair of leakage detection terminals 120 are exposed to the outside of the case portion 101. One of the pair of leakage detection terminals 120 is a positive electrode terminal. The other of the pair of leakage detection terminals 120 is a negative electrode terminal. As with the liquid crystal light control film 130, the conductor connected to the positive electrode leakage detection terminal 120 is connected to the positive electrode terminal 201 of each battery cell 200 with the electrolyte absorber 300 sandwiched in the middle. On the other hand, the conductor connected to the negative electrode leakage detection terminal 120 is directly connected to the negative electrode terminal 202 of each battery cell 200.

[0024] Fig. 2 shows a circuit diagram of the battery cell 200, the electrolyte absorbent material 300, and the circuit that conducts current during leakage in the battery pack 100 according to this embodiment, and Fig. 3 shows an equivalent circuit diagram of the circuit shown in Fig. 2. In these figures, a liquid crystal light control film 130 is shown as an example of the circuit that conducts current during leakage.

[0025] If no electrolyte is leaking from any of the battery cells 200, the electrolyte absorbent material 300 wrapped around any of the battery cells 200 does not absorb any electrolyte. Therefore, all of the electrolyte absorbent materials 300 act as insulators. Therefore, no voltage is applied to the liquid crystal light control film 130, which is the part that conducts electricity during leakage.

[0026] On the other hand, if electrolyte leaks from any of the battery cells 200, the electrolyte absorbent material 300 wrapped around the leaked battery cell 200 absorbs the electrolyte. The electrolyte absorbent material 300 that has absorbed the electrolyte becomes conductive due to the absorbed electrolyte. Therefore, the liquid crystal light control film 130, which is the current-carrying part in the event of leakage, is electrically connected to the battery cell 200 that is not leaking electrolyte via the electrolyte absorbent material 300 that has absorbed the electrolyte, and a voltage is applied to the liquid crystal light control film 130, which is the current-carrying part in the event of leakage. In this way, the electrolyte absorbent material 300 is equivalent to a switch that opens when it is not absorbing electrolyte and closes when it absorbs electrolyte.

[0027] The liquid crystal light control film 130 is exposed on the surface of the case of the battery pack 100. On the back side of the liquid crystal light control film 130, a message, mark, icon, or other display is provided to notify the user that electrolyte leakage has occurred in the battery cell 200 inside the case 101. When no voltage is applied, the liquid crystal light control film 130 is opaque and does not transmit visible light. In this state, the display indicating that electrolyte leakage has occurred is not visible. On the other hand, when voltage is applied to the liquid crystal light control film 130, the liquid crystal light control film 130 becomes transparent and allows visible light to transmit. Therefore, the user can see the display indicating that electrolyte leakage has occurred through the liquid crystal light control film 130. The liquid crystal light control film 130 configured in this manner is an example of a notification unit that displays an abnormality in the battery cell 200.

[0028] The liquid crystal light control film 130, which is the notification unit, should be installed in a position that is easily visible to the user, such as on the top surface of the case 101 of the battery pack 100 or on the installation surface of the handle 102. The indication on the back side of the liquid crystal light control film 130 should be a warning color such as red, orange, or yellow.

[0029] The notification unit may notify an abnormality in the battery cell 200 by sound or light instead of by display. That is, the leakage current-carrying unit may have a notification unit that notifies an abnormality in the battery cell 200 by at least one of sound, light, and display. When notifying an abnormality in the battery cell 200 by sound, the notification unit has, for example, a speaker or buzzer. When notifying an abnormality in the battery cell 200 by light, the notification unit has, for example, a lamp such as an LED.

[0030] When the leakage current-carrying part includes the leakage detection terminal 120 and electrolyte leaks from a battery cell 200, the behavior is the same as when the leakage current-carrying part includes the liquid crystal light control film 130. In other words, if electrolyte is not leaking from any of the battery cells 200, the electrolyte absorbent material 300 wrapped around any of the battery cells 200 does not absorb the electrolyte. Therefore, all of the electrolyte absorbent materials 300 act as insulators. Therefore, no voltage is applied to the leakage detection terminal 120, which is the leakage current-carrying part.

[0031] On the other hand, if electrolyte leaks from any of the battery cells 200, the electrolyte absorber 300 wrapped around the leaking battery cell 200 absorbs the electrolyte. The absorbed electrolyte makes the electrolyte absorber 300 conductive. Therefore, the leakage detection terminal 120, which serves as a current-carrying part in the event of leakage, is electrically connected to the battery cell 200 that is not leaking electrolyte via the absorbed electrolyte absorber 300, and a voltage is applied to the leakage detection terminal 120, which serves as a current-carrying part in the event of leakage. Therefore, for example, an external device such as an electrical device or charger that uses the battery pack 100 can detect the occurrence of an abnormality associated with electrolyte leakage in a battery cell 200 in the battery pack 100 by detecting the voltage across the leakage detection terminal 120.

[0032] According to the battery pack 100 configured as described above, when an abnormality occurs in which electrolyte leaks from a battery cell 200 included in the battery pack 100, the battery pack 100 alone can output a notification that an abnormality has occurred in the battery cell 200, or can output a voltage change between the leakage detection terminals 120. In this case, the output that an abnormality has occurred in the battery cell 200 is performed using power supplied from a battery cell 200 that is not leaking electrolyte. Therefore, with a simple configuration, it is possible to suppress the progression of a failure due to electrolyte leakage while outputting a notification that an abnormality has occurred in the battery cell 200, thereby improving safety.

[0033] Next, an example of the configuration of a battery cell 200 according to this embodiment will be described with reference to FIG. 4. As shown in the figure, the battery cell 200 includes a positive terminal 201, a negative terminal 202, an exterior part 221, and a battery main body part 222. The battery main body part 222 generates an electromotive force through an electrochemical reaction. The battery main body part 222 includes a positive electrode, a negative electrode, a separator, and an electrolyte (not shown). The battery main body part 222 is surrounded by the positive terminal 201, the negative terminal 202, and the exterior part 221. As a result, the electrolyte contained in the battery main body part 222 is sealed inside the battery cell 200.

[0034] The positive electrode includes a positive electrode active material. The negative electrode includes a negative electrode active material. Any material capable of absorbing and releasing lithium ions, which are the main component of battery operation, can be used as the positive electrode active material and the negative electrode active material. Specifically, for example, the positive electrode active material can be a composite oxide of lithium and a transition metal such as cobalt, nickel, or manganese, a chalcogen compound containing lithium, or a composite compound thereof. Furthermore, the positive electrode active material can be a composite oxide to which various additive elements have been added. Specifically, for example, the negative electrode active material can be graphitizable carbon, non-graphitizable carbon, carbon-based compounds such as polyacene and polyacetylene, or aromatic hydrocarbon compounds containing an acene structure such as pyrene and perylene.

[0035] A separator and electrolyte are disposed between the positive and negative electrodes. The separator is, for example, a porous polypropylene sheet. The separator is impregnated with the electrolyte. The electrolyte can be a non-aqueous solvent and lithium-containing electrolyte salt used in known batteries. Specifically, a single solution of an ether-based solvent such as dimethoxyethane, diethoxyethane, diethyl ether, or dimethyl ether, or an ester-based solvent such as ethylene carbonate, propylene carbonate, diethyl carbonate, or dimethyl carbonate, or a mixture of two or more of the aforementioned solvents, can be used. Furthermore, electrolyte salts that can be used for the electrolyte include LiPF6, LiAsF6, LiClO4, LiBF4, LiCF3SO3, LiN(CF3SO2)2, and LiC(CF3SO2).

[0036] The positive terminal 201 is electrically connected to the positive electrode of the battery main body 222. The positive terminal 201 is disposed on one end side of the battery cell 200. The negative terminal 202 is electrically connected to the negative electrode of the battery main body 222. The positive terminal 201 is disposed on the other end side of the battery cell 200.

[0037] In the configuration example shown in the figure, each of the positive terminal 201 and the negative terminal 202 has a conductive polymer 210. The conductive polymer 210 is conductive and dissolves when it comes into contact with the electrolyte solution sealed in the battery cell 200.

[0038] In the illustrated example, each of the positive terminal 201 and the negative terminal 202 includes a conductive polymer 210, a conductor 211, and an insulator 212. The conductor 211 is electrically connected to the positive electrode or negative electrode of the battery main body 222. The insulator 212 is in contact with the conductor 211. The conductive polymer 210 is in contact with both the conductor 211 and the insulator 212. The conductive polymer 210, the insulator 212, and the conductor 211 are arranged in this order from the outermost end of each of the positive terminal 201 and the negative terminal 202. In this manner, the conductive polymer 210 is in contact with the conductor 211 on the side closer to the battery main body 222. The conductive polymer 210 is in contact with only the insulator 212 on the side farther from the battery main body 222, i.e., on the side closer to the outermost end of the positive terminal 201 or the negative terminal 202.

[0039] When no electrolyte is leaking from the battery cell 200, the conductive polymer 210 at the outermost parts of the positive terminal 201 and the negative terminal 202 remains in contact with the conductor 211. Therefore, the outermost parts of the positive terminal 201 and the negative terminal 202 are electrically connected to the positive electrode and negative electrode of the battery main body 222, respectively, via the conductive polymer 210 and the conductor 211.

[0040] On the other hand, if the electrolyte leaks from the battery cell 200, when the leaked electrolyte reaches the conductive polymer 210, the conductive polymer 210 that comes into contact with the electrolyte dissolves. In this case, the conductive polymer 210 dissolves, particularly from the side closest to the battery main body 222. As a result, the portion of the conductive polymer 210 that is in contact with the conductor 211 dissolves first, and the conductive polymer 210 is no longer in contact with the conductor 211 and is in contact only with the insulator 212. Then, when the dissolution of the conductive polymer 210 progresses further and the conductive polymer 210 is completely dissolved, the insulator 212 is exposed at the outermost ends of each of the positive terminal 201 and the negative terminal 202.

[0041] When the conductive polymer 210 is not in contact with the conductor 211 and is in contact only with the insulator 212, the conductive polymer 210 at the outermost ends of the positive terminal 201 and the negative terminal 202 is not electrically connected to the positive and negative electrodes of the battery main body 222. Furthermore, when all of the conductive polymer 210 is dissolved, even in a state where the insulator 212 is exposed at the outermost ends of each of the positive terminal 201 and the negative terminal 202, the insulator 212 at the outermost end of the negative terminal 202 is not electrically connected to the positive and negative electrodes of the battery main body 222.

[0042] Thus, the conductive polymer 210 dissolves upon contact with the electrolyte, severing one or both of the electrical connection between the positive electrode and the outermost end of the positive terminal 201 and the electrical connection between the negative electrode and the outermost end of the negative terminal 202. When an electrolyte leaks from a battery cell 200 including such a conductive polymer 210, the leaked electrolyte dissolves the conductive polymer 210 in the positive and negative terminals, electrically disconnecting the outermost ends of the positive and negative terminals from the positive and negative electrodes. This allows the discharge or charging of a battery cell 200 in which electrolyte leakage has occurred to be stopped. Therefore, it is possible to stop charging or discharging a battery cell 200 in which electrolyte leakage has occurred and continue charging or discharging battery cells 200 in which electrolyte leakage has occurred. This simple configuration suppresses the progression of failures due to electrolyte leakage while allowing the use of other battery cells 200 in which electrolyte leakage has not occurred to continue, thereby improving safety.

[0043] In the configuration example described above, the conductive polymer 210 is provided in each of the positive electrode side terminal 201 and the negative electrode side terminal 202. However, the configuration is not limited to one in which the conductive polymer 210 is provided in both the positive electrode side terminal 201 and the negative electrode side terminal 202. The conductive polymer 210 may be provided in only one of the positive electrode side terminal 201 and the negative electrode side terminal 202, or the conductive polymer 210 may not be provided in either the positive electrode side terminal 201 or the negative electrode side terminal 202.

[0044] Furthermore, the conductive polymer 210 may be provided in the battery pack 100 instead of in each battery cell 200 housed in the battery pack 100. In this case, the conductive polymer 210 is provided, for example, inside the case portion 101. The conductive polymer 210 is provided in one or both of the middle of the conductor connecting the positive terminal 201 of the battery cell 200 to the positive charging / discharging terminal 110 and the middle of the conductor connecting the negative terminal 202 of the battery cell 200 to the negative charging / discharging terminal 110.

[0045] The conductive polymer 210 may be disposed anywhere inside the case 101 as long as it can come into contact with the electrolyte leaked from the battery cells 200. However, similar to the electrolyte absorbent material 300, the conductive polymer 210 should be disposed in close proximity to each battery cell 200 so as to ensure reliable and efficient contact with the electrolyte leaked from the battery cells 200. For example, if the battery cells 200 are held by a holder, the conductive polymer 210 may be provided on the holder.

[0046] When the conductive polymer 210 provided midway in the conductor connecting the positive terminal 201 of the battery cell 200 from which the electrolyte has leaked and the positive charging / discharging terminal 110 dissolves, the electrical connection between the positive terminal 201 of the battery cell 200 and the positive charging / discharging terminal 110 is severed. Also, when the conductive polymer 210 provided midway in the conductor connecting the negative terminal 202 of the battery cell 200 from which the electrolyte has leaked and the negative charging / discharging terminal 110 is dissolved, the electrical connection between the negative terminal 202 of the battery cell 200 and the negative charging / discharging terminal 110 is severed. That is, when the conductive polymer 210 comes into contact with the electrolyte leaked from the battery cell 200, it dissolves and cuts off one or both of the electrical connection between the positive terminal 201 of the battery cell 200 from which the electrolyte has leaked and the positive side charging / discharging terminal 110, and the electrical connection between the negative terminal 202 of the battery cell 200 from which the electrolyte has leaked and the negative side charging / discharging terminal 110.

[0047] With the battery pack 100 configured in this manner, when electrolyte leaks from one of the battery cells 200 in the case 101, the leaked electrolyte dissolves the conductive polymer 210, electrically disconnecting the leaked battery cell 200 from the charge / discharge terminals 110. This makes it possible to stop discharging or charging the battery cell 200 in which electrolyte leakage has occurred, while continuing to charge and discharge the battery cells 200 in which electrolyte leakage has not occurred. This makes it possible to suppress the progression of failure due to electrolyte leakage with a simple configuration, while continuing to use the other battery cells 200 in which electrolyte leakage has not occurred, thereby achieving both improved safety and improved convenience.

[0048] Next, a modified version of the battery pack 100 of this embodiment will be described with reference to Figures 5 and 6. In this modified version, the battery pack 100 further includes a battery pack connection operation switch 150. Figure 5 shows the circuit of the battery pack 100 of this modified version, including the battery cell 200, electrolyte absorbent material 300, battery pack connection operation switch 150, and leakage current-carrying unit, and Figure 6 shows an equivalent circuit of the circuit shown in Figure 5.

[0049] In the configuration examples shown in these figures, the leakage current conducting unit further includes an LED 140 as a notification unit. This LED 140 is an example of a notification unit that notifies of an abnormality in the battery cell 200 by light.

[0050] Furthermore, a battery pack connection operation switch 150 is inserted in the conductor connecting the electrolyte absorbent material 300 and the LED 140. The battery pack connection operation switch 150 is a switch that opens and closes depending on whether the battery pack 100 is connected to an electrical device or a charger. The battery pack connection operation switch 150 is, for example, a microswitch, a magnetic switch, a photoelectric switch, or the like. The battery pack connection operation switch 150 opens when the battery pack 100 is properly attached to an electrical device, a charger, or the like. The battery pack connection operation switch 150 closes when the battery pack 100 is not attached to an electrical device, a charger, or the like.

[0051] When the battery pack 100 is not connected to either an electrical device or a charger, the battery pack connection operation switch 150 allows an electrical connection between the battery cells from which the electrolyte is not leaking and the LED 140 serving as the notification unit via the electrolyte absorbent material 300 that has absorbed the electrolyte. Furthermore, when the battery pack 100 is connected to an electrical device or a charger, the battery pack connection operation switch 150 cuts off the electrical connection between the battery cells and the LED 140 serving as the notification unit.

[0052] According to the modified example of the battery pack 100 configured as described above, when the battery pack 100 is not connected to either an electrical device or a charger, the battery pack connection operation switch 150 is closed. Therefore, when electrolyte leaks from a battery cell 200, a voltage is applied to the LED 140 from the battery cell 200 that is not leaking electrolyte via the electrolyte absorbent material 300 that has absorbed the electrolyte, and the LED 140 lights up. Therefore, when the battery pack 100 is in a standalone state, detached from an electrical device, a charger, etc., an abnormality in the battery cell 200 can be notified by the light from the LED 140 in addition to the display by the liquid crystal light control film 130.

[0053] On the other hand, when the battery pack 100 is attached to an electric device, a charger, or the like, there is a possibility that the LED 140 will be inside the device and will not be visible. Therefore, in such a case, even if the battery pack connection operation switch 150 is opened and the electrolyte leaked from the battery cell 200 is absorbed by the electrolyte absorbent material 300, voltage is not applied from the battery cell 200 to the LED 140, thereby suppressing unnecessary discharge in the battery cell 200 from which the electrolyte is not leaking.

[0054] When the battery pack 100 is attached to an electric device, a charger, or the like, an abnormality in the battery cell 200 can be detected on the device side where the battery pack 100 is attached, for example, by using the leakage detection terminal 120. When an abnormality in the battery cell 200 is detected using the leakage detection terminal 120, the abnormality in the battery pack 100 can be reported from, for example, a pilot lamp, a display, a speaker, or the like of the device where the battery pack 100 is attached.

[0055] Furthermore, if the battery pack 100 or the battery cells 200 are provided with the conductive polymer 210 described above, when electrolyte leaks from one of the battery cells 200 in the case portion 101, the battery cell 200 in which the electrolyte leak has occurred can be electrically disconnected from the charge / discharge terminals 110. As a result, one or both of the voltage and current of the charge / discharge terminals 110 change before and after the occurrence of electrolyte leakage. Therefore, even if the leakage detection terminals 120 are not provided, the device to which the battery pack 100 is attached can detect an abnormality in the battery cells 200 using the charge / discharge terminals 110. [Explanation of symbols]

[0056] 100 battery packs 101 Case part 102 Handle 110 Charge / discharge terminal 120 Leak detection terminal 130 Liquid crystal light control film 140 LED 150 Battery pack connection operation switch 200 battery cells 201 Positive terminal 202 Negative terminal 210 Conductive Polymers 211 Conductor 212 Insulator 221 Exterior part 222 Battery body 300 Electrolyte absorbent

Claims

1. a battery cell with an electrolyte sealed inside; a case portion that houses the plurality of battery cells therein; an electrolyte absorbent material provided inside the case portion and configured to absorb the electrolyte leaked from the battery cell; a leakage current-carrying section electrically connected to the battery cell from which the electrolyte is not leaking via the electrolyte absorption material that has absorbed the electrolyte.

2. 2. The battery pack according to claim 1, wherein the leakage current supply unit includes a notification unit that notifies the user of an abnormality in the battery cell by at least one of sound, light, and display.

3. When the battery pack is not connected to either an electrical device that supplies power from the battery pack or a charger that charges the battery pack, the battery cell from which the electrolyte is not leaking can be electrically connected to the notification unit via the electrolyte absorbent material that has absorbed the electrolyte, The battery pack according to claim 2 , wherein the battery pack disconnects the electrical connection between the battery cells and the notification unit when the battery pack is connected to the electrical device or the charger.

4. 2. The battery pack according to claim 1, wherein the leakage current-carrying portion is exposed to the outside of the case portion and has a pair of leakage detection terminals that respectively conduct electricity to the positive and negative electrodes of the battery cells from which the electrolyte is not leaking.

5. a pair of terminals exposed to the outside of the case and electrically connected to the positive and negative electrodes of the battery cells, respectively; a conductive polymer provided inside the case portion between the positive electrode and the terminal and / or between the negative electrode and the terminal; 5. The battery pack according to claim 1, wherein the conductive polymer dissolves upon contact with the electrolyte leaked from the battery cell, thereby cutting off one or both of an electrical connection between the positive electrode of the battery cell from which the electrolyte leaked and the terminal and an electrical connection between the negative electrode of the battery cell from which the electrolyte leaked and the terminal.

6. a battery cell with an electrolyte sealed inside; a case portion that houses the plurality of battery cells therein; a pair of terminals exposed to the outside of the case and electrically connected to the positive and negative electrodes of the battery cells, respectively; a conductive polymer provided inside the case portion between the positive electrode and the terminal and / or between the negative electrode and the terminal; The conductive polymer dissolves when it comes into contact with the electrolyte leaked from the battery cell, thereby cutting off one or both of the electrical connection between the positive electrode of the battery cell from which the electrolyte leaked and the terminal and the electrical connection between the negative electrode of the battery cell from which the electrolyte leaked and the terminal.

7. A battery containing an electrolyte therein, a positive electrode including a positive electrode active material; a negative electrode including a negative electrode active material; a separator and the electrolyte solution disposed between the positive electrode and the negative electrode; a positive electrode terminal electrically connected to the positive electrode; a negative electrode terminal electrically connected to the negative electrode; a conductive polymer provided on one or both of the positive terminal and the negative terminal, The conductive polymer dissolves upon contact with the electrolyte solution, thereby cutting off one or both of the electrical connection between the positive electrode and the outermost end of the positive terminal and the electrical connection between the negative electrode and the outermost end of the negative terminal.

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