WO2013001585A1

WO2013001585A1 - Battery module

Info

Publication number: WO2013001585A1
Application number: PCT/JP2011/007173
Authority: WO
Inventors: 俊樹糸井; 永山　雅敏; 安井　俊介; 大輔岸井
Original assignee: パナソニック株式会社
Priority date: 2011-06-28
Filing date: 2011-12-21
Publication date: 2013-01-03
Also published as: JP2014170613A

Abstract

A battery module (200) comprises: a plurality of unit cells respectively further comprising discharge units which eject gas which is emitted within the cells; a heat transmission member (220) further comprising a plurality of cylindrical housing units which house the plurality of unit cells; and a lid body (270) which covers the discharge units of the plurality of unit cells and forms an internal space with the heat transmission member (220). The discharge units communicate with the internal space. The heat transmission member (220) further comprises a ventilation path between the plurality of housing units which is parallel to the axial direction of the housing units. One end side of the ventilation path communicates with the internal space, and the other end side thereof communicates with the outside.

Description

Battery module

The present invention relates to a battery module, and more particularly to a battery module in which a plurality of batteries are stored in a storage container and electrically connected in parallel to each other.

In recent years, demands for secondary batteries such as nickel metal hydride, nickel cadmium, and lithium ion that can be used repeatedly are increasing from the viewpoint of resource saving and energy saving. Among these, lithium ion secondary batteries are characterized by high electromotive force and high energy density while being lightweight. For this reason, the demand for lithium ion secondary batteries as driving power sources for many types of mobile communication devices and portable electronic devices such as mobile phones, digital cameras, video cameras, and notebook computers is increasing.

On the other hand, in order to reduce the amount of fossil fuel used and reduce the amount of CO ₂ emitted, there is an increasing expectation for a battery pack of a lithium ion secondary battery as a power source for driving a motor such as an automobile. In order to obtain a desired voltage and capacity, the battery pack is configured by mounting a plurality of battery modules including one or more batteries.

In the development of such a battery module, it is required to reduce the size of the battery module in order to store the battery module that stores predetermined power in a limited space such as an automobile.

Therefore, in a battery module composed of a plurality of batteries, for example, Patent Document 1 discloses a configuration having a pattern wiring in which the batteries are connected to each other and wiring for detecting the voltage or temperature of each battery is formed on a printed circuit board. Yes. With such a configuration, it is not necessary to newly provide a lead wire or the like for detecting a voltage or the like connected to each battery, so that the size can be reduced. Similarly, for example, Patent Document 2 discloses a battery pack in which a plurality of power supply modules are housed in a holder case and connected via an end plate. In Patent Document 2, it is said that the connection failure can be reduced and the size can be reduced by providing the end plate with a sensor lead and a power supply lead for connecting the power supply modules.

Also, as the capacity of the battery stored in the battery module increases, the battery itself may generate heat and become high temperature depending on the form of use. For this reason, not only the safety of the battery itself, but also the safety of the battery module assembled with them is becoming more important. That is, in the battery, the internal pressure increases due to gas generated by overcharge, overdischarge, internal short circuit, or external short circuit, and in some cases, the battery outer case may be lost. Therefore, generally, a battery is provided with a vent mechanism or a safety valve for venting gas to release internal gas. At this time, the exhausted gas may react with oxygen and burn, which has a problem in reliability and safety.

Therefore, by storing a plurality of batteries in the battery chamber in the case and providing an opening in the partition wall facing the safety valve of each battery, the gas injected from the battery in an abnormal state is discharged from the discharge port through the exhaust chamber. A power supply device (battery module) configured to be discharged to the outside is presented in Patent Document 3, for example.

JP 2000-208118 A JP 2000-223166 A JP 2007-27011 A

However, in the battery modules shown in Patent Document 1 and Patent Document 2, when one battery abnormally generates heat and the safety valve operates, the amount of heat of the generated battery and the influence of surrounding gas due to the combustion of the ejected gas are suppressed. There is a problem that the batteries generate heat in a chain. That is, in a battery module equipped with a plurality of batteries, it is important how to suppress the influence of an abnormal battery to a minimum by suppressing expansion to surrounding batteries.

Also, the battery module shown in Patent Document 3 is provided with an opening on the partition wall of the case so as to face the safety valve of the battery, and the ejected gas is discharged outside without filling the battery chamber. However, although the discharge of the ejected gas is described, there is no disclosure or suggestion of preventing combustion due to the reaction between oxygen and gas. For this reason, when combustion of gas occurs, it is unclear how to prevent combustion in the partition wall. Moreover, when a combustion prevention device or the like is arranged, there arises a problem that the battery module cannot be reduced in size.

The present invention has been made in view of the above-mentioned problems, and its main purpose is to realize miniaturization and thinning, and to minimize the influence on the surrounding batteries due to the malfunction of the defective battery. An object of the present invention is to provide a battery module capable of satisfying the requirements.

In order to achieve the above object, the battery module of the present invention includes a plurality of unit cells each having an open part for discharging gas generated inside the battery, and a plurality of cylindrical storage units for storing the plurality of unit cells. A heat transfer member, and a cover that covers the open portions of the plurality of unit cells and forms an internal space between the heat transfer members, the open portion communicates with the internal space, and the heat transfer member is A ventilation path parallel to the axial direction of the storage section is provided between the plurality of storage sections, and one end side of the ventilation path communicates with the internal space and the other end side communicates with the outside.

With this configuration, even if a situation occurs in which high temperature gas is ejected from the battery, the temperature can be lowered when the ejected high temperature gas passes through the air passage provided in the heat transfer member. Moreover, since the ventilation path is provided in the area | region between the some accommodating parts which accommodates the battery of a heat-transfer member, size reduction of a battery module is not prevented.

The battery module of the present invention further includes an electrode connection body that electrically connects the electrode portions of the plurality of unit cells, and the electrode connection body is provided so as to be in close contact with the plurality of unit cells, and includes a plurality of storage units. Each of these is preferably sealed.

This configuration can prevent an abnormal battery from affecting the surrounding batteries.

According to the battery module of the present invention, it is possible to prevent the high temperature gas from being ejected from the battery module even when a situation in which the high temperature gas is ejected from the battery occurs while suppressing an increase in the size and weight of the battery module. A high battery module can be obtained.

FIG. 1 is a cross-sectional view showing a unit cell used in a battery module according to an embodiment of the present invention. FIG. 2 is an exploded perspective view showing the configuration of the battery module according to the embodiment of the present invention. FIG. 3 is a perspective view showing a battery module according to an embodiment of the present invention. FIG. 4A is a perspective view showing an example of a heat transfer member of a battery module according to an embodiment of the present invention, and FIG. 4B is a perspective view showing an example of a heat transfer member in which a unit cell is accommodated. It is. FIG. 5A is a perspective view showing another example of the heat transfer member of the battery module according to the embodiment of the present invention, and FIG. 5B is another example of the heat transfer member in which the unit cell is accommodated. FIG. FIG. 6A is a plan view showing a heat transfer member in which a unit cell of the battery module according to the embodiment of the present invention is housed, and FIG. 6B shows a positive electrode on the heat transfer member of FIG. It is a top view which shows the structure in which the connection body for operation was provided. FIG. 7 is a cross-sectional view showing a battery module according to an embodiment of the present invention. FIG. 8 is a schematic view showing a temperature lowering mechanism of the battery module according to one embodiment of the present invention.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. In addition, this invention is not limited to the following embodiment. Moreover, it can change suitably in the range which does not deviate from the range which has the effect of this invention.

A unit cell used in a battery module according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a cross-sectional view showing a unit cell used in a battery module according to an embodiment of the present invention. Note that the battery module of the present embodiment is configured as an assembly including a plurality of unit cells arranged and a plurality of unit cells and a heat transfer member for storing the unit cells.

For example, a cylindrical lithium ion secondary battery can be adopted as the unit cell constituting the battery module according to the present embodiment. This lithium ion secondary battery may be a general-purpose battery used as a power source for portable electronic devices such as notebook computers. In this case, since a high-performance general-purpose battery can be used as a unit cell of the battery module, it is possible to easily improve the performance and cost of the battery module. Moreover, the unit cell is provided with a safety mechanism that releases gas to the outside of the battery when the pressure in the battery increases due to an internal short circuit or the like. In addition, the unit cell used in the present embodiment is not limited to the shape and type described above, and may be, for example, a square battery or the like, or a nickel hydrogen battery or the like.

As shown in FIG. 1, the unit cell 100 which comprises the battery module which concerns on this embodiment has the electrode group 4 by which the positive electrode plate 1 and the negative electrode plate 2 were wound through the separator 3 with a non-aqueous electrolyte. The battery case 7 is housed. Insulating

plates

9, 10 are arranged above and below the electrode group 4, the positive electrode plate 1 is joined to the filter 12 via the positive electrode lead 5, and the negative electrode plate 2 serves as the negative electrode terminal via the negative electrode lead 6. It is joined to the bottom of the case 7.

The filter 12 is connected to an inner cap 13, and the protrusion of the inner cap 13 is joined to a metal valve body 14. Further, the valve body 14 is connected to a terminal plate 8 that also serves as a positive electrode terminal, and the terminal plate 8 has an open portion 8a. The terminal plate 8, the valve body 14, the inner cap 13 and the filter 12 are integrated, and the opening of the battery case 7 is sealed via the gasket 11.

When an internal short circuit or the like occurs in the unit cell 100 and the pressure in the unit cell 100 increases, the valve body 14 swells toward the terminal plate 8 and the inner cap 13 and the valve body 14 are disconnected from each other. Is cut off. When the pressure in the unit cell 100 further increases, the valve body 14 is broken. Thereby, the gas generated in the unit cell 100 is discharged to the outside through the through hole 12 a of the filter 12, the through hole 13 a of the inner cap 13, the tear of the valve body 14, and the opening 8 a of the terminal plate 8. The

Note that the safety mechanism for discharging the gas generated in the unit cell 100 to the outside as described above is not limited to the structure shown in FIG. 1, but may be another structure.

Next, a battery module according to an embodiment of the present invention will be described with reference to FIGS. FIG. 2 is an exploded perspective view showing the configuration of the battery module according to one embodiment of the present invention, and FIG. 3 is a perspective view showing the configuration of the battery module according to one embodiment of the present invention.

As shown in FIG. 2, the battery module 200 according to the present embodiment includes a plurality (20 in FIG. 2) of unit cells 100, a heat transfer member 220, a positive electrode side holder 250, a negative electrode side holder 260, and a positive electrode. The connecting member (electrode connecting member) 230, the negative electrode connecting member 240, and the lid 270 are configured.

The plurality of unit cells 100 are housed in the housing portion 222 of the heat transfer member 220 so that the open portion 8a of the terminal plate 8, that is, the positive electrode faces the same direction (upward in FIG. 2). Then, the negative electrode connector 240 is welded to the negative electrodes of the plurality of unit cells 100 with the negative electrode side holder 260 sandwiched between the negative electrodes of the unit cells 100. In addition, the positive electrode connection body 230 is welded to the positive electrodes of the plurality of unit cells 100 across the positive electrode side holder 250 on the positive electrode side of the unit cell 100, and the unit cell 100 that is exposed from the storage unit 222 by the lid 270 is opened. The internal space (exhaust chamber) is formed between the positive electrode connection body 230 and the lid body 270 so as to cover the portion 8 a and the positive electrode connection body 230. Finally, the positive electrode side holder 250 and the negative electrode side holder 260 are fixed with screws 280 from above and below the battery module 200. As a result, as shown in FIG. 3, a battery module 200 in which all the components are combined is obtained. In FIG. 3, since the plurality of unit cells 100 are covered, the unit cells 100 are not visible from the outside. Further, the positive electrode output terminal 232 at the end of the positive electrode connection body 230 and the negative electrode output terminal 242 at the end of the negative electrode connection body 240 are exposed to the outside of the battery module 200 in order to take out current from the battery module 200. It has a structure.

Next, details of the battery module according to the embodiment of the present invention will be described with reference to FIGS. FIG. 4A is a perspective view showing an example of a heat transfer member of a battery module according to an embodiment of the present invention, and FIG. 4B is a perspective view showing an example of a heat transfer member in which a unit cell is accommodated. It is. FIG. 5 (a) is a perspective view showing another example of the heat transfer member of the battery module according to the embodiment of the present invention, and FIG. 5 (b) shows another heat transfer member in which the unit cell is housed. FIG. Moreover, Fig.6 (a) is a top view which shows the heat-transfer member in which the unit cell of the battery module which concerns on one Embodiment of this invention was accommodated, FIG.6 (b) is the heat-transfer member of Fig.6 (a). It is a top view which shows the structure by which the connection body for positive electrodes was provided. FIG. 7 is a cross-sectional view showing a battery module according to an embodiment of the present invention.

As shown in FIGS. 4A and 4B, the heat transfer member 220 is formed with a plurality of cylindrical storage portions 222 that store the unit cells 100. Here, the “cylindrical shape” refers to a shape having a hollow portion in the axial direction, and its cross-sectional shape is not particularly limited, and includes, for example, a circle, an ellipse, a quadrangle, and the like. That is, the shape of the storage portion 222 can be determined as appropriate according to the shape of the unit cell 100 to be stored. In the present embodiment, the cylindrical storage unit 222 is used because the cylindrical unit cell 100 is used. The shape is not limited to this, and any shape that can accommodate the unit cell 100 may be used.

The storage unit 222 has an inner diameter that is about 0.2 mm larger than the outer diameter of the unit cell 100 in order to store the cylindrical unit cell 100, and is arranged in a hexagonal close-packed lattice shape. Furthermore, the heat transfer member 220 is formed with a ventilation path 221 that is a through hole parallel to the axial direction of the storage portion 222. The air passage 221 is disposed at the center of gravity of the three storage portions 222 adjacent to each other. When the unit cell 100 is a battery having a size of, for example, “18650” (the outer diameter is 18.2 mm at the maximum and the height is 65 mm), the storage unit 222 has a length of 55 mm. The inner diameter of 222 is 18.4 mm.

In the present embodiment, the heat transfer member 220 has a structure in which the housing portion 222 and the air passage 221 passing through the block made of metal or the like are formed. However, as shown in FIGS. A heat transfer member 225 having a structure in which the side surfaces of the plurality of cylindrical members 226 are connected by welding or the like may be used. In such a heat transfer member 225, the unit cell 100 is stored in each of the storage portions 227 that are cavities of the plurality of cylindrical members 226. The heat transfer member 225 has, for example, 20 cylindrical members 226 each having a plate thickness of 0.4 mm, an inner diameter of 18.4 mm, and a height of 55 mm arranged in a hexagonal close-packed lattice. Thereby, the heat transfer member 225 can have the ventilation path 228 in the gravity center of the three cylindrical members 226 (housing part 227) adjacent to each other.

When the unit cell 100 is accommodated in the heat transfer member 220, as shown in FIG. 6A, the air passage 221 is arranged around the unit cell 100 at intervals of 60 °. In particular, in the vicinity of the center of the heat transfer member 220, the unit cell 100 surrounded by six other unit cells 100 has a structure in which six air passages 221 are arranged around the unit cell 100.

Further, as shown in FIGS. 6B and 7, the positive electrode connector 230 is connected to the positive electrode side via the positive electrode side holder 250 with respect to the heat transfer member 220 containing the plurality of unit cells 100. The negative electrode connector 240 is combined with the negative electrode side holder 260 on the side. Also, a lid 270 is provided so as to cover the positive electrode connection body 230, and an internal space 271 surrounded by the positive electrode connection body 230 and the lid body 270 is formed. The positive electrode side holder 250, the positive electrode connection body 230, the negative electrode side holder 260, and the negative electrode connection body 240 are combined with the heat transfer member 220 at the same position as the air passage 221, and through

holes

254, 233 having the same size. 262 and 243, respectively. For this reason, the battery module 200 has a hole communicating from the positive electrode connector 230 to the negative electrode connector 240.

Furthermore, when combined with the heat transfer member 220, the positive electrode side holder 250 and the negative electrode side holder 260 have a concave portion having the same size and the same size at the same position as the housing portion 222, and a slightly smaller opening at the bottom of the concave portion. Has a part. The positive electrode connection body 230 and the negative electrode connection body 240 are electrically connected to the unit cell 100 by disposing the positive electrode connection terminal 231 and the negative electrode connection terminal 241 at the same position as the housing portion 222. The positive electrode connection body 230 has an opening 234 that communicates with the open portion 8 a of the unit cell 100 around the positive electrode connection terminal 231. That is, the open part 8 a of the unit cell 100 communicates with the internal space 271 through the opening 234, and the high temperature gas from the open part 8 a is released into the internal space 271. Further, the positive electrode connection body 230 is provided so as to be in close contact with each of the unit cells 100 via the positive electrode side holder 250, and seals the storage portion 222. In addition, the sealing here does not necessarily mean a completely sealed state, but includes a state in which a gas that does not affect the unit cell 100 enters the storage unit 222. Further, in this embodiment, since the positive electrode connection body 230 made of a conductor is used, the insulating positive electrode side is provided so that the positive electrode connection body 230 and the negative electrode (battery case 7) of the unit cell 100 are not short-circuited. The positive electrode connector 230 is in close contact with the unit cell 100 through the holder 250. However, the configuration is not limited to this as long as the positive electrode connector 230 and the negative electrode (battery case 7) of the unit cell 100 can prevent a short circuit. For example, the positive electrode connection body 230 may be formed by forming a wiring pattern for connecting the positive electrodes of the plurality of unit cells 100 in parallel on an insulating wiring board. In this case, the positive electrode side holder 250 is not provided. It doesn't matter. In this way, the storage unit 222 is hermetically sealed, so that the high-temperature gas released from the abnormal unit cell 100 does not enter the surrounding normal unit cell 100 and the normal unit cell 100 generates heat or the like. Can be prevented.

In this embodiment, since the unit cell 100 has the open part 8a that discharges the high-temperature gas only on the positive electrode side, there is no need to provide an opening in the negative electrode connector 240, but the positive electrode connector 230 and the negative electrode It is also possible to use the connecting member 240 for the same part.

Next, the temperature lowering mechanism of the battery module according to this embodiment will be described with reference to FIG. FIG. 8 is a schematic view showing a temperature lowering mechanism of the battery module according to this embodiment.

As shown in FIG. 8, when the unit cell 100x is in an abnormal state and generates heat, a high temperature gas of 700 ° C. to 1000 ° C. is discharged from the open portion 8a in the terminal plate 8 on the positive electrode side of the unit cell 100x. The high-temperature gas discharged from the open portion 8 a passes through the opening 234 of the positive electrode connection body 230 and is discharged into the internal space 271 surrounded by the positive electrode connection body 230 and the lid body 270. Since the volume of the internal space 271 does not allow all of the released high temperature gas to enter, the high temperature gas released to the internal space 271 passes through the communicating passage 221 and the through

holes

233, 254, 262, 243, respectively. Then, it is pushed out from the negative electrode connector 240 side (downward in the figure). In FIG. 8, the direction in which the hot gas flows is indicated by an arrow.

The air passage 221 and the through

holes

233, 254, 262, and 243 do not have an opening area sufficient to discharge the discharge amount of the high-temperature gas discharged from the unit cell 100x per unit time, so that quick discharge is possible. Can not. For this reason, the hot gas is discharged while contacting the inner wall of the air passage 221 of the heat transfer member 220. When the high temperature gas contacts the inner wall of the ventilation path 221, the heat transfer member 220 absorbs heat of the high temperature gas at 700 ° C. to 1000 ° C. Further, while the high temperature gas is exhausted through the air passage 221, the internal space 271 has a pressure higher than the atmospheric pressure, and air does not flow in from the outside. No heat is generated by combustion.

Further, since the air passage 221 does not have an opening area sufficient to discharge the discharge amount of the hot gas per unit time, the hot gas gradually moves to the atmospheric pressure as it flows through the discharge passage such as the air passage 221. The pressure will drop. At this time, the temperature of the hot gas decreases due to adiabatic expansion. For these reasons, the hot gas is cooled to about 300 ° C. when discharged from the through hole 243 of the negative electrode connector 240 to the outside.

As described above, even when a high temperature gas of 700 ° C. to 1000 ° C. is generated, the temperature of the high temperature gas decreases to about 300 ° C. while passing through the air passage 221. Further, in the present embodiment, the positive electrode connector 230 is provided so as to be in close contact with the plurality of unit cells 100 and the plurality of storage units 222 are sealed, so that the high temperature gas is introduced from the unit cell 100x in which an abnormality has occurred. Even if released into the space 271, the hot gas can be prevented from entering the other normal unit cell 100, and the normal unit cell 100 can be prevented from being affected by heat generation or the like.

As described above, the air passage 221 of the heat transfer member 220 has a long and narrow shape in order to lower the temperature while allowing the generated high temperature gas to pass therethrough. The length of the air passage 221 is desirably 20 times or more the shortest distance from the center point of the opening cross section of the air passage 221 to the inner wall. Here, the “center point” means a point farthest from the inner wall of the air passage 221 and is a point where heat is most difficult to be transmitted to the heat transfer member 220. In this way, the high temperature gas released from the unit cell 100 is sufficiently absorbed by the heat transfer member 220 when passing through the air passage 221, and the temperature at the center point where heat is most difficult to transfer is released to the outside at 300 ° C. or less. Can be done. The ventilation path 221 has a length of, for example, 20 mm to 200 mm, an opening area of 0.5 mm ² to 50 mm ² , and when the unit cell 100 is a battery having a size of “18650”, for example, The length is 55 mm, and the inner diameter of the air passage 221 is 3 mm.

Further, the heat transfer member 220 is a metal having a thermal conductivity of 200 W / (m · K) or more in order to quickly dissipate the heat to the outside of the battery module when any of the unit cells 100 abnormally generates heat. Or it is comprised with the ceramic material. For example, in the present embodiment, aluminum having a thermal conductivity of 236 W / (m · K) is used for the heat transfer member 220.

According to the battery module of one embodiment of the present invention, the heat transfer member has a through hole substantially parallel to the storage portion between the plurality of storage portions, so that the unit cell can be exhausted in an abnormal state without hindering downsizing. Since the hot gas to be cooled is cooled when passing through the air passage and the through hole, the temperature of the hot gas can be lowered.

As mentioned above, although this invention has been demonstrated by suitable embodiment, such description is not a limitation matter and of course various modifications are possible. For example, as long as the positive electrode connection body 230 and the negative electrode connection body 240 in this embodiment connect the positive electrode and the negative electrode of the several unit cell 100 in parallel, respectively, the form will not be ask | required. For example, the positive electrode connection body 230 and the negative electrode connection body 240 may be formed of bus bars made of a metal material. Moreover, in the said embodiment, although it was set as the structure which discharges high temperature gas outside through the positive electrode connection body which is an electrode connection body from the positive electrode side facing a positive electrode upwards, a negative electrode connection body is turned to a negative electrode upwards. The high temperature gas may be discharged to the outside from the negative electrode side. Moreover, the wiring pattern which connects the positive electrode and negative electrode of the several unit cell 100 in parallel may be formed on the insulating wiring board. In this case, the wiring board may be disposed on the positive electrode side of the unit cell 100, and wiring patterns for connecting the positive electrode and the negative electrode in parallel may be formed on the wiring board. At this time, it is not necessary to provide a wiring board on the negative electrode side of the unit cell 100.

The present invention is useful as a battery module storing a battery or the like that is required to be safe and small in size and weight, as well as an electronic device including the battery module and an electronic device including a storage portion.

100 unit cell 200 battery module 220 heat transfer member 221 air passage 222 storage portion 225 heat transfer member 226 cylindrical member 227 storage portion 228 air passage 230 positive electrode connection body 231 positive electrode connection terminal 232 positive electrode output terminal 233 through hole 234 opening 240 Negative electrode connection body 241 Negative electrode connection terminal 242 Negative electrode output terminal 243 Through hole 250 Positive electrode side holder 254 Through hole 260 Negative electrode side holder 262 Through hole 270 Lid 271 Internal space 280 Screw

Claims

A plurality of unit cells each having an open portion for discharging gas generated inside the battery;
A heat transfer member having a plurality of cylindrical storage portions for storing the plurality of unit cells;
A cover that covers the open portions of the plurality of unit cells and forms an internal space with the heat transfer member;
The open portion communicates with the internal space;
The heat transfer member has a ventilation path parallel to the axial direction of the storage portion between the plurality of storage portions,
One end side of the air passage communicates with the internal space, and the other end side communicates with the outside.
In claim 1,
Further comprising an electrode connection body for electrically connecting the electrode parts of the plurality of unit cells,
The electrode connector is a battery module that is provided in close contact with the plurality of unit cells and seals each of the plurality of storage units.
In claim 2,
The open part is formed in the electrode part, and is in communication with the internal space through an opening part formed in the electrode connector.
In any one of claims 1 to 3,
The length of the air passage is a battery module that is 20 times or more the shortest distance from the center point of the opening cross section of the air passage to the inner wall.
In claim 4,
The battery module has a length of 20 mm or more and 200 mm or less and an opening area of 0.5 mm 2 or more and 50 mm 2 or less.
In claim 1,
The storage portion has a cylindrical shape, and is arranged in a hexagonal close-packed lattice shape on the heat transfer member,
The air passage is a battery module arranged at the center of gravity of the three storage units adjacent to each other.
In claim 1,
The heat transfer member is a battery module configured such that side surfaces of a plurality of cylindrical members are connected to each other.
In claim 1,
The heat transfer member is a battery module made of a metal or ceramic material having a thermal conductivity of 200 W / (m · K) or more.