JP2020042968A - Power storage device module - Google Patents

Abstract

To provide a power storage device module capable of detecting thermal runaway in a power storage device.SOLUTION: In a secondary battery module 10, as a power storage device module, including a plurality of secondary batteries 11, each as a power storage device, connected in parallel therein, each secondary battery 11 includes an electrode assembly and a case 21 receiving the electrode assembly therein. The secondary battery module 10 includes: detection wiring 41 arranged while being in contact with the cases 21 of all of the secondary batteries 11, and supplied with current, portions in contact with the cases 21 being electrically connected with each other; and a detector 43 detecting the conduction state of the detection wiring 41.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a power storage device module in which a plurality of power storage devices are connected in parallel.

  BACKGROUND ART Conventionally, a secondary battery module as a power storage device module in which a plurality of secondary batteries as power storage devices is connected in parallel has been known. Each secondary battery includes an electrode assembly in which a plurality of electrodes are stacked, a case accommodating the electrode assembly, and electrode terminals that exchange electricity with the electrode assembly and connect the inside and outside of the case. The plurality of secondary batteries are connected in parallel by connecting the electrode terminals by bus bars.

  In such a secondary battery, due to an internal short circuit or overcharging / discharging, a specific member constituting the secondary battery generates heat, and the heat generated by the specific member causes other members to generate heat. In some cases, the exothermic reaction repeats uncontrollably (heat runaway), such as another member generating heat. When the secondary battery has run out of heat, the temperature of the secondary battery continues to rise spontaneously.

  Patent Literature 1 discloses a configuration of a secondary battery module for suppressing such thermal runaway. In the secondary battery module disclosed in Patent Document 1, each secondary battery constituting the secondary battery module has a fuse. Therefore, when the current flowing through at least one of the secondary batteries constituting the secondary battery module becomes abnormal, the fuse of the secondary battery having the abnormal current is blown. Thereby, the current flow in the secondary battery in which the current has become abnormal is stopped. As a result, thermal runaway of the secondary battery having an abnormal current is suppressed.

JP 2016-18688 A

  However, even if each secondary battery has a configuration having a fuse, even if thermal runaway of the secondary battery is suppressed, occurrence of thermal runaway is not always completely suppressed. Therefore, detection of thermal runaway of the secondary battery is required.

  SUMMARY An advantage of some aspects of the invention is to provide a power storage device module that can detect a thermal runaway of a power storage device.

  A power storage device module for solving the above problems is a power storage device module in which a plurality of power storage devices are connected in parallel, and each of the power storage devices includes an electrode assembly and a case for housing the electrode assembly. A detection member, which is disposed in contact with the cases of all of the power storage devices, is supplied with current, and is electrically connected to portions that are in contact with the case, and is electrically connected to the detection members. And a detection unit that detects a state.

  When at least one power storage device among the plurality of power storage devices undergoes thermal runaway, the temperature of the case of the thermal storage device that has undergone thermal runaway becomes high. For this reason, the detection members arranged in contact with the cases of all the power storage devices are melted by the heat of the case that has become hot due to thermal runaway, and no current flows to the detection members. That is, the conduction state of the detection member is interrupted. Therefore, thermal runaway of the power storage device can be detected by detecting the conduction state of the detection member by the detection unit.

  In the above power storage device module, it is preferable that the detection member has a conductive member and a covering portion formed of an insulating material and covering the conductive member, and the covering portion is in contact with the case. .

In the above power storage device module, the detection member is preferably linear.
In the above power storage device module, it is preferable that the detection member has a plate shape.

  A power storage device module for solving the above problems is a power storage device module in which a plurality of power storage devices are connected in parallel, each of the power storage devices is an electrode assembly, and a case that houses the electrode assembly, A pressure release valve that is present on the wall of the case and is opened when the pressure in the case reaches the release pressure, and releases the pressure in the case to the outside of the case; A detection member which is arranged to face the pressure release valve, is supplied with current, and has a portion electrically connected to the portion facing the pressure release valve, and a detection member for detecting a conduction state of the detection member. And a unit.

  When at least one of the plurality of power storage devices undergoes thermal runaway, the pressure release valve of the thermally runaway power storage device is opened, and high-temperature gas is ejected from the opened portion. For this reason, the detection members arranged opposite to the pressure release valves of all the power storage devices are physically cut by the split pressure release valves, or are melted by the jetted high-temperature gas, and are thus detected. No current flows through That is, the conduction state of the detection member is interrupted. Therefore, thermal runaway of the power storage device can be detected by detecting the conduction state of the detection member by the detection unit.

Further, in the power storage device module, it is preferable that the detection member is disposed to face the pressure release valve in a state of being in contact with the case.
Further, in the power storage device module, it is preferable that the detection member is disposed to face the pressure release valve in a state where the detection member is separated from the case.

  In the power storage device module, it is preferable that charging or discharging of the power storage device is stopped when the detection unit detects that the conduction state of the detection member is not in communication.

  According to the present invention, thermal runaway of a power storage device can be detected.

FIG. 3 is a perspective view of a secondary battery module. FIG. 4 is a cross-sectional view of a secondary battery. FIG. 2 is a plan view of the secondary battery module according to the first embodiment. FIG. 4 is a plan view showing the operation of the secondary battery module according to the first embodiment. FIG. 5 is a perspective view showing a secondary battery module according to a second embodiment. FIG. 9 is an exemplary perspective view showing the operation of the secondary battery module according to the second embodiment;

(First embodiment)
Hereinafter, a first embodiment in which a power storage device module is embodied as a secondary battery module will be described with reference to FIGS.

  As shown in FIG. 1, a secondary battery module 10 as a power storage device module includes a plurality (eight in the present embodiment) of secondary batteries 11 as power storage devices. The secondary battery module 10 is mounted on a vehicle such as an EV (Electric Vehicle) or a PHV (Plug in Hybrid Vehicle), and is used to store power supplied to an electric motor and the like. The secondary battery 11 of the present embodiment is a lithium ion secondary battery.

  As shown in FIG. 2, each secondary battery 11 includes a case 21, an electrode assembly 22 housed in the case 21, and an electrolytic solution (not shown) housed in the case 21. The case 21 has a case main body 23 having a bottomed quadrangular cylindrical shape, and a rectangular flat lid 24 for closing an opening 23 a of the case main body 23. The case body 23 and the lid 24 each constitute a wall of the case 21. The case body 23 and the lid 24 are both made of metal (for example, stainless steel or aluminum). The case body 23 has a rectangular plate-shaped bottom wall 23b, a long side wall 23c standing upright from a pair of long side edges of the bottom wall 23b, and a short side standing upright from a pair of short side edges of the bottom wall 23b. And a side wall 23d. The secondary battery 11 of the present embodiment is a prismatic battery having a rectangular appearance.

  Although not shown, the electrode assembly 22 includes a plurality of positive electrodes, a plurality of negative electrodes, and a plurality of separators. The electrode assembly 22 has a layered structure in which a separator is interposed between a positive electrode and a negative electrode, and the layers are stacked in a state where they are insulated from each other. The direction in which the positive electrode, the negative electrode, and the separator are stacked is referred to as a stacking direction. Each of the positive electrode and the negative electrode has a rectangular sheet-shaped current collector and active material layers present on both surfaces of the current collector. Each of the positive electrode and the negative electrode has a tab protruding from a part of one side of the current collector. The tab has no active material layer and is formed of the current collector itself. The positive electrode and the negative electrode are stacked such that the positive electrode tabs are arranged in rows along the stacking direction, and the negative electrode tabs are arranged in rows along the stacking direction.

  The electrode assembly 22 includes a positive electrode tab group 25a in which positive electrode tabs are gathered and stacked, and a negative electrode tab group 25b in which negative electrode tabs are gathered and stacked. In the electrode assembly 22, the end face on which the positive electrode tab group 25a and the negative electrode tab group 25b exist is referred to as a tab side end face 22a. The tab-side end surface 22a faces the inner surface of the lid 24.

  Each secondary battery 11 includes a positive electrode terminal structure 26a and a negative electrode terminal structure 26b that exchange electricity with the electrode assembly 22. The positive electrode terminal structure 26a includes a plate-shaped positive electrode connection member 27a electrically connected to the positive electrode tab group 25a, and a positive electrode terminal 28a electrically connected to the positive electrode connection member 27a. Similarly, the negative electrode terminal structure 26b includes a plate-shaped negative electrode connection member 27b electrically connected to the negative electrode tab group 25b, and a negative electrode terminal 28b electrically connected to the negative electrode connection member 27b. Each of the positive electrode terminal 28a and the negative electrode terminal 28b has a base 281 and a shaft 282 protruding from the base 281. The base 281 of the positive terminal 28a is connected to the positive connecting member 27a inside the case 21, and the base 281 of the negative terminal 28b is connected to the negative connecting member 27b inside the case 21. Each shaft portion 282 connects the inside and the outside of the case 21 by having the end opposite to the base portion 281 penetrate the lid 24 and protrude to the outside of the case 21. Each of the positive electrode terminal 28a and the negative electrode terminal 28b has a male screw groove on an outer peripheral surface of a portion of the shaft portion 282 protruding outside the case 21, and is fixed to the lid 24 by screwing a nut 29 into the male screw groove. ing. Each of the positive electrode terminal 28a and the negative electrode terminal 28b is formed from an end surface of the shaft portion 282 opposite to the base 281 toward the base 281 and includes a connection hole 282a having a female screw groove on an inner peripheral surface.

  Each secondary battery 11 includes a pressure release valve 30 on the lid 24. The pressure release valve 30 ruptures when the pressure in the case 21 reaches a predetermined release pressure so that the pressure in the case 21 does not increase excessively when gas is generated inside the case 21. . When the pressure release valve 30 ruptures, the gas in the case 21 blows out of the case 21 from the ruptured portion. Thereby, the pressure in the case 21 is released to the outside of the case 21.

  In such a secondary battery 11, a specific member constituting the secondary battery 11 generates heat due to an internal short circuit or overcharge, and other members generate heat due to the heat generated by the specific member. In some cases, the exothermic reaction may be uncontrollably repeated (heat runaway) such that another member generates heat. For example, when the separator is broken by the foreign matter in the case 21 or the creep phenomenon and the positive electrode and the negative electrode are short-circuited, a current flows between the positive electrode and the negative electrode to generate heat. When the temperature reaches a predetermined temperature (about 120 to 130 ° C.), the SEI film formed on the surface of the negative electrode is thermally decomposed, and the electrolyte adheres to the surface of the negative electrode exposed by the thermal decomposition of the SEI film. As a result, the electrolytic solution undergoes reductive decomposition, and gas is generated in the case 21. The exothermic reaction is repeated in this way. When the secondary battery 11 runs away from heat, the pressure inside the case 21 increases due to the gas generated by the reductive decomposition of the electrolytic solution. For this reason, the pressure release valve 30 of the secondary battery 11 is opened, and the high-temperature gas in the case 21 is ejected from the opened portion of the pressure release valve 30. The temperature of the gas ejected by operating the pressure release valve 30 due to the thermal runaway of the secondary battery 11 is about 600 degrees, and the pressure in the case 21 increases when the secondary battery 11 is not thermally runaway. The temperature is sufficiently higher than the temperature (approximately 50 degrees or less) of the gas ejected by the operation of the pressure release valve 30. Further, since the temperature of the secondary battery 11 continues to rise spontaneously, the temperature of the electrode assembly 22 and the case 21 containing the electrolytic solution also become high. Note that, in the secondary battery 11 that has undergone thermal runaway, the pressure release valve 30 operates before the temperature of the case 21 becomes high.

  As shown in FIGS. 1 and 3, the eight secondary batteries 11 are arranged in a row so that the long side walls 23 c of each case 21 face each other. The direction in which the secondary batteries 11 are arranged is referred to as an arrangement direction, and the eight secondary batteries 11 are referred to as first to eighth secondary batteries 11a to 11h from one end side to the other end side in the arrangement direction. The first secondary battery 11a and the second secondary battery 11b are arranged such that the positive terminals 28a and the negative terminals 28b are adjacent to each other in the arrangement direction. The third secondary battery 11c, the fourth secondary battery 11d, the fifth secondary battery 11e, the sixth secondary battery 11f, the seventh secondary battery 11g, and the eighth secondary battery 11h are also provided. Similarly, the positive terminals 28a and the negative terminals 28b are arranged so as to be adjacent to each other in the arrangement direction. The positive terminal 28a of the third secondary battery 11c is adjacent to the negative terminal 28b of the second secondary battery 11b, and the positive terminal 28a of the fourth secondary battery 11d is connected to the fifth secondary battery 11e. Next to the negative electrode terminal 28b. The positive terminal 28a of the sixth secondary battery 11f is adjacent to the negative terminal 28b of the seventh secondary battery 11g.

  The eight secondary batteries 11 are connected in parallel by being connected by a plurality of (three in this embodiment) plate-shaped bus bars 31 to 33. The first bus bar 31 includes a negative terminal 28b of the first secondary battery 11a, a negative terminal 28b of the second secondary battery 11b, a positive terminal 28a of the third secondary battery 11c, and a fourth secondary battery. This is a state penetrated by the positive electrode terminal 28a of 11d. The second bus bar 32 includes a negative terminal 28b of the third secondary battery 11c, a negative terminal 28b of the fourth secondary battery 11d, a positive terminal 28a of the fifth secondary battery 11e, and a sixth secondary battery. This is a state penetrated by the positive electrode terminal 28a of 11f. The third bus bar 33 includes a negative terminal 28b of a fifth secondary battery 11e, a negative terminal 28b of a sixth secondary battery 11f, a positive terminal 28a of a seventh secondary battery 11g, and an eighth secondary battery. 11h is a state penetrated by the positive electrode terminal 28a. Then, in a state where the first to third bus bars 31 to 33 are penetrated by the respective positive electrode terminals 28a and the respective negative electrode terminals 28b, the bolts 34 are screwed into the female screw grooves of the connection holes 282a of the respective shaft portions 282. , The secondary batteries 11 are connected to each other. In the present embodiment, the eight secondary batteries 11 are in a state in which four sets of two secondary batteries 11 connected in parallel are connected in series.

  As shown in FIG. 3, the secondary battery module 10 includes a detection device 40 for detecting thermal runaway of the secondary battery 11. The detection device 40 includes a detection wire 41 as a detection member. The detection wiring 41 has a conductive wire (aluminum wire in the present embodiment) 41a as a conductive member, and a covering portion 41b that covers the conductive wire 41a. The covering portion 41b is formed of a material having an insulating property (a resin in the present embodiment). The detection wiring 41 is arranged in contact with all the secondary batteries 11 constituting the secondary battery module 10. In the present embodiment, the detection wiring 41 is arranged such that the covering portion 41b contacts the outer surface of one short side wall 23d of the case main body 23 of the eight secondary batteries 11. Portions of the detection wiring 41 that are in contact with the respective cases 21 are electrically connected to each other by a conductive wire 41a. The diameter of the detection wiring 41 is set to a diameter such that the detection wiring 41 is melted by the heat of the case 21 which has become high temperature due to thermal runaway of the secondary battery 11.

  The detecting device 40 includes a power supply 42 for supplying a current to the conducting wire 41a, and a detecting unit 43 for detecting a thermal runaway of the secondary battery 11 from a conduction state of the conducting wire 41a. The detection unit 43 of the present embodiment includes an ammeter 44 for measuring a current flowing through the conductor 41a, and a determination unit 45 connected to the ammeter 44. The power supply 42 and the ammeter 44 are each connected in series to the conductor 41a. The determination unit 45 determines the conduction state of the conductive wire 41a from the current measured by the ammeter 44. When the current measured by the ammeter 44 is 0 (zero), the determination unit 45 determines that the conduction state of the conductive wire 41a is not conducting. The determination unit 45 is signal-connected to a control device 46 that controls charging and discharging of the secondary battery 11. When the determining unit 45 determines that the conduction state of the conductive wire 41a is disconnected, it transmits a signal to the control device 46.

The operation of the first embodiment will be described.
As shown in FIG. 3, when the eight secondary batteries 11 do not run out of heat, the current supplied from the power supply 42 flows through the conductor 41a. For this reason, the ammeter 44 measures the current flowing through the conductor 41a, and the determination unit 45 determines that the conductor 41a is conducting because the ammeter 44 measures the current of the conductor 41a. Therefore, the determination unit 45 does not transmit a signal to the control device 46.

  As shown in FIG. 4, for example, when the fifth secondary battery 11 e out of the eight secondary batteries 11 undergoes thermal runaway, the case 21 of the fifth secondary battery 11 e that has undergone thermal runaway becomes hot. For this reason, the detection wiring 41 arranged in contact with the case 21 of each secondary battery 11 is melted and cut off by the heat of the case 21 of the fifth secondary battery 11e, which has become hot, and a current flows through the conductor 41a. Disappears. Therefore, the current value measured by the ammeter 44 becomes 0 (zero), and the determination unit 45 determines that the conduction state of the conductive wire 41a is disconnected, and transmits a signal to the control device 46. Upon receiving the signal from the determination unit 45, the control device 46 stops charging or discharging the secondary battery 11.

The effect of the first embodiment will be described.
(1-1) When at least one of the plurality of secondary batteries 11 constituting the secondary battery module 10 undergoes thermal runaway, the temperature of the case 21 of the secondary battery 11 that has undergone thermal runaway becomes high. For this reason, the detection wires 41 arranged in contact with the cases 21 of all the secondary batteries 11 are melted by the heat of the case 21 which has been heated to a high temperature due to thermal runaway, and current flows through the conductor 41 a of the detection wires 41. Stops flowing. That is, the conduction state of the conducting wire 41a is interrupted. Therefore, the thermal runaway of the secondary battery 11 can be detected by detecting the conduction state of the conducting wire 41a by the detecting unit 43.

  Further, as a method for detecting thermal runaway of the secondary batteries 11, for example, a method in which temperature sensors are provided in all the secondary batteries 11 and thermal runaway is detected by the temperature sensors can be considered. However, in this method, it is necessary to prepare the same number of temperature sensors as the number of the secondary batteries 11 constituting the secondary battery module 10, resulting in high cost. Although the cost can be reduced by providing a temperature sensor for every two or more, a thermal runaway can be detected when a secondary battery 11 different from the secondary battery 11 provided with the temperature sensor has thermal runaway. This occurs after heat is transferred from the case 21 of the secondary battery 11 that has run out of heat to the case 21 of the secondary battery 11 provided with a temperature sensor. Therefore, the detection of the thermal runaway is delayed. On the other hand, in the present embodiment, one detection wiring 41 is arranged so as to be in contact with the cases 21 of all the secondary batteries 11, and only the conduction state of the conductor 41 a of the detection wiring 41 is detected. Thermal runaway of the secondary battery 11 can be detected. Therefore, thermal runaway of the secondary battery 11 can be detected quickly and at low cost.

  As another method of detecting thermal runaway of the secondary battery 11, for example, a method of measuring the voltage across both ends of a plurality of secondary batteries 11 connected in parallel and detecting thermal runaway based on the measured voltage is also considered. Can be However, in this method, if any one of the plurality of secondary batteries 11 connected in parallel does not undergo thermal runaway, no voltage abnormality occurs and thermal runaway cannot be detected. On the other hand, in the present embodiment, since one detection wiring 41 is arranged to be in contact with the cases 21 of all the secondary batteries 11, one of the plurality of secondary batteries 11 connected in parallel is connected. Even if a thermal runaway occurs, it can be detected.

  (1-2) The detection wiring 41 is blown by the heat of the case 21 of the secondary battery 11 that has run away from heat. For this reason, as in the second embodiment described later, the pressure release valve 30 is split by thermal runaway of the secondary battery 11 and the detection wire 41 is blown off by high-temperature gas ejected from the split portion. In comparison, the thermal runaway of the secondary battery 11 can be stably detected.

  (1-3) The conducting wire 41a of the detection wiring 41 is covered with a covering portion 41b made of an insulating material. Therefore, it is possible to prevent the current flowing through the conductive wire 41 a from flowing through the case 21 of the secondary battery 11.

(1-4) Since the detection member is the detection wire 41, the detection member is easily blown compared to the case where the detection member has a plate shape. Therefore, thermal runaway of the secondary battery 11 can be detected immediately.
(1-5) When the detecting unit 43 detects that the conduction state of the conducting wire 41a is not conducting, that is, when detecting the thermal runaway of the secondary battery 11, the control device 46 causes the charging or discharging of the secondary battery 11 to be performed. Can be stopped.

(Second embodiment)
Hereinafter, a second embodiment that embodies the secondary battery module will be described with reference to FIGS. The description of the same configuration as that of the first embodiment is omitted.

  As shown in FIG. 5, the detection wiring 41 of the detection device 40 is disposed so as to face the pressure release valves 30 of all the secondary batteries 11. In the present embodiment, the detection wiring 41 is supported by a support (not shown) in a state where it is separated from the lid 24 of each secondary battery 11. The portions of the detection wiring 41 that face each pressure release valve 30 are electrically connected by a conductive wire 41a. The diameter of the detection wiring 41 and the distance between the pressure release valve 30 and the detection wiring 41 are determined by the high-temperature gas ejected from the cleaved portion when the pressure release valve 30 is ruptured due to thermal runaway of the secondary battery 11. The diameter and the distance are set to such an extent that the detection wiring 41 can be blown.

The operation of the second embodiment will be described.
As shown in FIG. 6, for example, when the fifth rechargeable battery 11 e out of the eight rechargeable batteries 11 runs out of heat, the pressure release valve 30 of the fifth rechargeable battery 11 e that has run out of heat is opened, and the splitting is performed. Hot gas gushes from the part. For this reason, the detection wiring 41 arranged opposite to the pressure release valve 30 of each secondary battery 11 is blown off by the heat of the ejected high-temperature gas, so that no current flows through the conductive wire 41a. Therefore, the current value measured by the ammeter 44 is 0 (zero), and the determination unit 45 determines that the conduction state of the conductive wire 41a is disconnected.

The effect of the second embodiment will be described.
(2-1) When at least one of the plurality of secondary batteries 11 constituting the secondary battery module 10 undergoes thermal runaway, the pressure release valve 30 of the thermal runaway secondary battery 11 is opened, Hot gas gushes from the cleaved part. For this reason, the detection wires 41 arranged to face the pressure release valves 30 of all the secondary batteries 11 are blown by the ejected high-temperature gas, so that no current flows through the conductive wires 41 a of the detection wires 41. That is, the conduction state of the conducting wire 41a is interrupted. Therefore, the thermal runaway of the secondary battery 11 can be detected by detecting the conduction state of the conducting wire 41a by the detecting unit 43.

  Further, as a method for detecting thermal runaway of the secondary batteries 11, for example, a method in which temperature sensors are provided in all the secondary batteries 11 and thermal runaway is detected by the temperature sensors can be considered. However, in this method, it is necessary to prepare the same number of temperature sensors as the number of the secondary batteries 11 constituting the secondary battery module 10, resulting in high cost. Although the cost can be reduced by providing a temperature sensor for every two or more, a thermal runaway can be detected when a secondary battery 11 different from the secondary battery 11 provided with the temperature sensor has thermal runaway. This occurs after heat is transferred from the case 21 of the secondary battery 11 that has run out of heat to the case 21 of the secondary battery 11 provided with a temperature sensor. Therefore, the detection of the thermal runaway is delayed. On the other hand, in the present embodiment, one detection wiring 41 is arranged so as to face the pressure release valves 30 of all the secondary batteries 11, and only the conduction state of the conductor 41 a of the detection wiring 41 is detected. Thus, thermal runaway of the secondary battery 11 can be detected. Therefore, thermal runaway of the secondary battery 11 can be detected quickly and at low cost.

  As another method of detecting thermal runaway of the secondary battery 11, for example, a method of measuring the voltage across both ends of a plurality of secondary batteries 11 connected in parallel and detecting thermal runaway based on the measured voltage is also considered. Can be However, in this method, if any one of the plurality of secondary batteries 11 connected in parallel does not undergo thermal runaway, no voltage abnormality occurs and thermal runaway cannot be detected. On the other hand, in the present embodiment, since one detection wiring 41 is arranged so as to face the pressure release valves 30 of all the secondary batteries 11, among the plurality of secondary batteries 11 connected in parallel, Even if one of them runs out of heat, it can be detected.

  (2-2) In the present embodiment, the detection wiring 41 is blown off by the gas ejected from the split pressure release valve 30. In the secondary battery 11 that has undergone thermal runaway, the pressure release valve 30 operates before the temperature of the case 21 becomes high. For this reason, the thermal runaway of the secondary battery 11 is detected more quickly than in the case where the detection wiring 41 is blown off by the heat of the case 21 of the secondary battery 11 that has runaway as in the first embodiment. be able to.

(2-3) Since the detection member is the detection wire 41, the detection member is easily blown compared to the case where the detection member has a plate shape. Therefore, thermal runaway of the secondary battery 11 can be detected immediately.
(2-4) When the detecting unit 43 detects that the conduction state of the conducting wire 41a is not conducting, that is, when detecting the thermal runaway of the secondary battery 11, the control unit 46 controls the charging or discharging of the secondary battery 11. Can be stopped.

  The first and second embodiments can be modified and implemented as follows. The first embodiment, the second embodiment, and the modifications can be implemented in combination with each other within a technically consistent range.

The number of the secondary batteries 11 constituting the secondary battery module 10 may be appropriately changed as long as it is two or more. However, it is assumed that the secondary batteries 11 are connected in parallel.
In the secondary battery module 10, if at least some of the secondary batteries 11 are connected in parallel, the connection mode may be changed as appropriate.

  In the first and second embodiments, the case where one of the eight secondary batteries 11 constituting the secondary battery module 10 undergoes thermal runaway has been described, but two or more secondary batteries 11 The battery 11 may run away at the same time.

(Circle) the secondary batteries 11 which comprise the secondary battery module 10 do not need to be arranged in a line, and the arrangement mode of the secondary batteries 11 may be changed suitably.
The shape of the case 21 is not limited to a rectangular parallelepiped, and may be changed as appropriate. For example, the case 21 may have a cylindrical shape having a bottomed cylindrical case main body 23 and a disc-shaped lid 24 for closing the opening 23a of the case main body 23.

The electrode assembly 22 housed in the case 21 is not limited to the so-called stacked electrode assembly described in the above embodiment, but may be a wound electrode assembly.
The pressure release valve 30 may be provided in the case main body 23.

The method of detecting the conduction state of the conductive wire 41a may be changed as appropriate. For example, the conduction state of the conductive wire 41a may be detected by a tester as the detection unit 43.
In the first embodiment, the conductive member of the detection member is not limited to a linear shape, and may be a plate shape. The thickness of the detection member is set to such a thickness that the detection member is blown by the heat of the case 21 which has become high temperature due to the thermal runaway of the secondary battery 11. In this case, since the contact area between the case 21 of the secondary battery 11 and the detection member is increased as compared with the case where the detection member is linear, the heat of the case 21 that has become hot due to thermal runaway is used for the detection. It is easy to transmit to the member.

  The material of the conductive wire 41a is not limited to aluminum and has only to have a low melting point that has conductivity and is melted by heat of the case 21 or high-temperature gas ejected from the pressure release valve 30. The material of the conductive wire 41a may be, for example, tin, a low melting point alloy, or a conductive plastic.

(Circle) the conducting wire 41a does not need to be covered with the covering part 41b.
In the first embodiment, the portion of the case 21 that contacts the detection wiring 41 is not limited to the outer surface of the short side wall 23d of the case body 23, and may be the outer surface of the bottom wall 23b or the long side wall 23c, or the cover 24. May be on the outside.

  In the second embodiment, the detection wiring 41 may be arranged so as to face the pressure release valve 30 in a state of being in contact with the outer surface of the lid 24 of each secondary battery 11. In this case, the distance between the detection wiring 41 and the pressure release valve 30 is short. Therefore, when at least one of the secondary batteries 11 among the plurality of secondary batteries 11 constituting the secondary battery module 10 undergoes thermal runaway and the pressure release valve 30 is opened, the detection wiring 41 is opened due to thermal runaway. The pressure relief valve 30 is physically disconnected by the pressure relief valve 30, so that no current flows through the conductor 41 a of the detection wiring 41. Further, as described above, the pressure release valve 30 operates before the temperature of the case 21 becomes high. Therefore, it is possible to detect the thermal runaway of the secondary battery 11 more quickly than in the case where the detection wiring 41 is blown off by the heat of the case 21 of the secondary battery 11 that has run away as in the first embodiment. Can be.

  The secondary battery module 10 may include a cooling plate disposed in contact with the bottom wall 23 b of the case 21 of all the secondary batteries 11. The cooling plate is, for example, an aluminum plate, and cools the secondary battery 11 by flowing cooling water below the cooling plate. The cooling plate may function as a conductive member of the detection member.

  The secondary battery module 10 does not have to include the power supply 42. In this case, a current is supplied to the conductive wire 41a by a power source mounted on the vehicle for a purpose different from the detection of thermal runaway of the secondary battery 11.

  The response after the detection section 43 detects the thermal runaway of the secondary battery 11 may be changed as appropriate. For example, when the secondary battery module 10 includes a fire extinguishing device, the fire extinguishing device may extinguish the secondary battery module 10 by transmitting a signal to the fire extinguishing device. Further, for example, the control device 46 may open the window of the vehicle, unlock the door of the vehicle, or display a warning to evacuate the vehicle on the display unit of the vehicle. .

  The secondary battery 11 is not limited to a lithium ion secondary battery, but may be another secondary battery such as a nickel hydride secondary battery. In short, any material may be used as long as ions move between the positive electrode active material and the negative electrode active material and transfer charges.

  The power storage device can be applied to a power storage device other than a secondary battery, such as a capacitor.

DESCRIPTION OF SYMBOLS 10 ... Rechargeable battery module as a power storage device module, 11 ... Secondary battery as a power storage device, 21 ... Case, 23 ... Case main body as a wall, 24 ... Lid as a wall, 22 ... Electrode assembly, 30 ... pressure release valve, 41 ... detection wiring as a detection member, 41a ... conductive wire as a conductive member, 41b ... coating part, 43 ... detection part.

Claims (8)

A power storage device module in which a plurality of power storage devices are connected in parallel,
Each of the power storage devices has an electrode assembly and a case for housing the electrode assembly,
A detection member that is arranged in contact with the cases of all of the power storage devices, is supplied with current, and has portions electrically connected to the case, electrically connected to each other,
A detection unit that detects a conduction state of the detection member,
A power storage device module comprising:   2. The power storage device module according to claim 1, wherein the detection member has a conductive member and a covering portion formed of an insulating material and covering the conductive member, and the covering portion contacts the case. 3.   The power storage device module according to claim 1, wherein the detection member is linear.   The power storage device module according to claim 1, wherein the detection member has a plate shape. A power storage device module in which a plurality of power storage devices are connected in parallel,
Each of the power storage devices is an electrode assembly, a case accommodating the electrode assembly, and a wall portion of the case, which is opened when the pressure in the case reaches an opening pressure, and the power storage device is opened in the case. A pressure release valve for releasing pressure outside the case,
A detection member that is arranged to face the pressure release valves of all of the power storage devices, is supplied with current, and has a portion that faces the pressure release valves electrically connected to each other,
A detection unit that detects a conduction state of the detection member,
A power storage device module comprising:   The power storage device module according to claim 5, wherein the detection member is arranged to face the pressure release valve while being in contact with the case.   The power storage device module according to claim 5, wherein the detection member is arranged to face the pressure release valve while being separated from the case. The power storage device module according to any one of claims 1 to 7, wherein the detection unit stops charging or discharging the power storage device when detecting that the conduction state of the detection member is not conducted.