ELECTRIC POWER STORAGE DEVICE

An electric power storage device includes an electric power storage module including a unit electric power storage portion, and a fixing member fixed to the electric power storage module. The electric power storage module includes a first exhaust port configured to discharge gas discharged from the unit electric power storage portion. The fixing member includes a fixing member body fixed to the electric power storage module and a cover member disposed on the fixing member body. The cover member is disposed on a surface of the fixing member body facing the electric power storage module. An exhaust passage, into which the gas discharged from the first exhaust port flows, is formed by the fixing member body and the cover member.

INCORPORATION BY REFERENCE

The disclosure of Japanese Patent Application No. 2017-004267 filed on Jan. 13, 2017 including the specification, drawings and abstract is incorporated herein by reference in its entirety.

BACKGROUND

1. Technical Field

The present disclosure relates to an electric power storage device.

2. Description of Related Art

There have conventionally been proposed various electric power storage devices including a plurality of unit cells and an exhaust mechanism that guides exhaust gas discharged from the unit cells.

For example, an electric power storage device described in Japanese Patent Application Publication No. 2013-114952 (JP 2013-114952 A) includes a plurality of battery blocks, end plates provided at end faces of each battery block, a safety valve duct provided at an upper surface of each battery block, and a gas duct. The battery blocks are arranged in one direction, and each battery block includes a plurality of unit cells. A safety valve is provided at an upper surface of each unit cell.

The safety valve duct is provided to connect the safety valves of the unit cells. An end plate pipe communicating with the safety valve duct is formed in the end plate. The end plate pipe reaches from an upper end face to a lower end face of the end plate.

The safety valve duct is connected to an upper end portion of the end plate pipe, while the gas duct is connected to a lower end portion of the end plate pipe.

In this electric power storage device, when an internal short circuit occurs in the unit cell, gas is ejected from the safety valve of the unit cell. The gas passes through the safety valve duct, the end plate pipe, and the gas duct in this order and is discharged to the outside.

SUMMARY

As a method of forming the end plate pipe in the end plate in the above-described electric power storage device, boring using a drill or the like may be considered. However, since the distance from the upper end face to the lower end face of the end plate is long, there is a possibility of the occurrence of drill bit breakage, biting of chips, or the like. Therefore, it is difficult to form the end plate pipe by machining the end plate.

In view of this, it may be considered to provide an exhaust duct or the like, which is for discharging gas from the unit cell, separately from the end plate. However, depending on a state of an internal short circuit or the like that occurs in the unit cell, a large amount of gas may be ejected violently from the unit cell, so that the exhaust duct may receive a large load from the gas when the gas enters the exhaust duct. Therefore, there is a possibility that a fixing member for firmly fixing the exhaust duct may be newly required, resulting in increase in size of the electric power storage device.

The present disclosure provides an electric power storage device, having a function to discharge gas from a unit electric power storage portion to the outside, which can be prevented from increasing in size and which is easy to manufacture.

A first aspect of the present disclosure relates to an electric power storage device. The electric power storage device includes an electric power storage module including a unit electric power storage portion, and a fixing member fixed to the electric power storage module. The electric power storage module includes a first exhaust port configured to discharge gas discharged from the unit electric power storage portion. The fixing member includes a fixing member body fixed to the electric power storage module and a cover member disposed on the fixing member body. The fixing member body includes a surface that faces the electric power storage module. The cover member is disposed on the surface. The fixing member body and the cover member define an exhaust passage into which the gas discharged from the first exhaust port flows.

In the first aspect of the present disclosure, the first exhaust port may be open to the exhaust passage.

In the first aspect of the present disclosure, the surface of the fixing member body may include a groove portion defined by an inner surface of the fixing member body. The exhaust passage may be defined by the cover member and the inner surface. The cover member may include a hole portion communicating with the first exhaust port.

In the first aspect of the present disclosure, the cover member may be made of an insulating material.

In the first aspect of the present disclosure, a base of the fixing member body may include a second exhaust port to which the exhaust passage is open.

In the first aspect of the present disclosure, the electric power storage module may include a heat dissipation plate, a negative-electrode bus bar assembly, and a bottom cover. An end face of the heat dissipation plate may include the first exhaust port. The heat dissipation plate may include a first exhaust passage open to the first exhaust port. The negative-electrode bus bar assembly may include a second exhaust passage communicating with the first exhaust passage. A third exhaust passage communicating with the second exhaust passage may be defined by the bottom cover and the negative-electrode bus bar assembly. A bottom surface of the unit electric power storage portion may include a safety valve exposed to the third exhaust passage.

In the first aspect of the present disclosure, the cover member may include a side surface facing the first exhaust port. The side surface may include a hole portion that is open to the first exhaust port. The hole portion may include a bottom portion at a position entering the cover member from the side surface, and the bottom portion may include a thin film portion configured to be melted by the gas discharged from the unit electric power storage portion.

According to the above-described electric power storage device, when gas is ejected from the unit electric power storage portion, the gas is ejected from the exhaust port into the exhaust passage.

The fixing member body is disposed to face the exhaust port and thus the gas mainly impinges on the fixing member body. Since the fixing member body is fixed to the electric power storage module, the fixing member body is prevented from being detached from the electric power storage module.

Even if the gas ejected from the exhaust port impinges on the cover member, the cover member receives a load from the gas in a direction so as to be pressed against the surface of the fixing member body. In this way, even when the gas is ejected from the unit electric power storage portion, the load that is applied in a direction in which the cover member is detached from the fixing member body can be suppressed to be small. Consequently, it is possible to omit a fixing member that is otherwise required for firmly fixing the cover member to the fixing member body. Further, since the exhaust passage can be formed by attaching the cover member to the fixing member body, the assembly is easy.

According to the electric power storage device, the electric power storage device can be prevented from increasing in size and can be easily assembled.

DETAILED DESCRIPTION OF EMBODIMENTS

An embodiment will be described with reference toFIGS. 1 to 11. Of the configurations shown inFIGS. 1 to 11, the same or substantially the same configurations will be assigned the same symbols, and description thereof may be omitted.

FIG. 1is a schematic diagram showing a vehicle2equipped with an electric power storage device1. As shown inFIG. 1, the vehicle2includes the electric power storage device1disposed in the vehicle2. The vehicle2equipped with the electric power storage device1is an electrically driven vehicle such as a hybrid vehicle or an electric vehicle, or a fuel cell vehicle.

The electric power storage device1includes a battery case3, a battery unit4, and a fan5. The battery unit4is housed in the battery case3. The fan5supplies the air in a passenger compartment into the battery case3.

FIG. 2is a perspective view showing the battery unit4of the electric power storage device1. As shown inFIG. 2, the electric power storage device1includes a plurality of battery modules10to13and fixing plates14and15(fixing members) respectively provided at both ends of the electric power storage device1. The electric power storage device1has a generally rectangular parallelepiped shape and is disposed longitudinally in a width direction of the vehicle2.

The fixing plate14is provided at a first end in a longitudinal direction of the electric power storage device1, while the fixing plate15is provided at a second end of the electric power storage device1.

The fixing plate14is fixed to the battery modules10to13by a plurality of bolts20to27, so that the battery modules10to13are fixed to each other by the fixing plate14. The fixing plate14is fixed to a bottom surface of the battery case3by bolts28and29. Like the fixing plate14, the fixing plate15is also fixed to the battery modules10to13and the bottom surface of the battery case3.

Accordingly, the battery modules10to13are coupled to each other and fixed to the bottom surface of the battery case3via the fixing plates14and15.

FIG. 3is an exploded perspective view showing the battery module10. As shown inFIG. 3, the battery module10includes a bottom cover40, a negative-electrode bus bar assembly41, a heat dissipation plate42, a plurality of cylindrical cells43, a resin cover44, a plurality of positive-electrode bus bars45, and a top cover46.

The heat dissipation plate42is a plate-like member made of a metal. The heat dissipation plate42is formed with a plurality of through-holes50extending in a thickness direction of the heat dissipation plate42. The through-holes50are arranged in an array.

The heat dissipation plate42has an upper surface51, a lower surface52, a pair of side surfaces53and54, and a pair of end faces55and56. Each through-hole50reaches from the upper surface51to the lower surface52.

Exhaust passages (first exhaust passages) and exhaust ports (first exhaust ports) are formed on the end face55side and the end face56side of the heat dissipation plate42. While an exhaust passage57and an exhaust port58formed on the end face55side are shown inFIG. 3, the same exhaust passage and the same exhaust port are formed also on the end face56side.

The exhaust passage57extends to enter the heat dissipation plate42from the lower surface52and then extends toward the end face55. Then, the exhaust passage57communicates with the exhaust port58formed at the end face55.

The cylindrical cell43is a chargeable and dischargeable secondary battery. The cylindrical cell43is, for example, a nickel-hydrogen battery or a lithium-ion battery. The cylindrical cell43is formed at its upper end with a positive electrode60and at its lower end with a negative electrode61. While the cylindrical cell is employed as a unit electric power storage portion in this embodiment, a prismatic battery or a capacitor may alternatively be employed.

The cylindrical cells43are respectively inserted into the through-holes50formed in the heat dissipation plate42. The positive electrodes60of the cylindrical cells43are located above the upper surface51of the heat dissipation plate42, while the negative electrodes61of the cylindrical cells43are located below the lower surface52of the heat dissipation plate42.

A resin or the like is provided between inner peripheral surfaces of the through-holes50of the heat dissipation plate42and outer peripheral surfaces of the cylindrical cells43, so that the cylindrical cells43are fixed to the heat dissipation plate42.

The resin cover44is disposed on the upper surface51of the heat dissipation plate42. The resin cover44is formed to be open downward and has a top plate65, a pair of side walls66and67, and a pair of end walls68and69.

Lower end portions of the side walls66and67and lower end portions of the end walls68and69are disposed on the upper surface51of the heat dissipation plate42.

The side wall66is formed with an upper flange70and a lower flange71. The upper flange70and the lower flange71are formed to extend from the end wall68to the end wall69and are provided at an interval in a vertical direction.

The side wall66is formed with a plurality of ventilation openings73at a portion located between the upper flange70and the lower flange71. Likewise, the side wall67is formed with a plurality of ventilation openings.

The upper flange70of the battery module10is in close contact with an upper flange70of the battery module12disposed adjacent to the battery module10, while the lower flange71of the battery module10is in close contact with a lower flange71of the battery module12. Consequently, a ventilation passage74is formed between the upper flanges70and the lower flanges71. The ventilation passage74communicates with the fan5. The top plate65is formed with a plurality of holes64into which the cylindrical cells43are respectively inserted.

The positive-electrode bus bars45are provided above the top plate65of the resin cover44. Each positive-electrode bus bar45connects the positive electrodes60of, for example, about10cylindrical cells43to each other.

The top cover46is disposed above the positive-electrode bus bars45. The top cover46is made of an insulating material such as a resin.

The negative-electrode bus bar assembly41is disposed on the lower surface52side of the heat dissipation plate42. The negative-electrode bus bar assembly41includes a plurality of negative-electrode bus bars (not shown) and a resin mold integrating the negative-electrode bus bars. The outer shape of the negative-electrode bus bar is similar to that of the positive-electrode bus bar45. The negative-electrode bus bar assembly41(negative-electrode bus bars) is formed with a plurality of holes75. Each hole75includes a terminal76that is formed to protrude from an inner peripheral surface of the hole75. The negative electrode61of the cylindrical cell43is connected to the terminal76.

Each negative-electrode bus bar is configured to connect to each other the negative electrodes61of the same cylindrical cells43as those of the corresponding positive-electrode bus bar45.

Therefore, the cylindrical cells43are electrically connected in parallel to each other by each negative-electrode bus bar and the corresponding positive-electrode bus bar45. The positive-electrode bus bars45and the negative-electrode bus bars are electrically connected to each other such that the sets each including the cylindrical cells43connected in parallel to each other by the negative-electrode bus bar and the positive-electrode bus bar45are connected in series to each other.

The negative-electrode bus bar assembly41is formed at its first end with an exhaust passage77(second exhaust passage) and at its second end with an exhaust passage78(second exhaust passage). The exhaust passages77and78are each formed to pass through the negative-electrode bus bar assembly41in a thickness direction.

The exhaust passage77communicates with the exhaust passage57formed in the heat dissipation plate42. The exhaust passage78communicates with the exhaust passage formed on the end face56side of the heat dissipation plate42.

The bottom cover40is disposed on the lower surface side of the negative-electrode bus bar assembly41. The bottom cover40is made of a metal such as aluminum.

FIG. 4is a sectional view showing the battery module10and a peripheral configuration thereof. As shown inFIG. 4, an exhaust passage80(third exhaust passage) is defined by the bottom cover40and the negative-electrode bus bar assembly41. A safety valve81is formed at a bottom surface of the cylindrical cell43and exposed to the exhaust passage80.

InFIGS. 3 and 4, the exhaust passage80communicates with the exhaust passage77and the exhaust passage78, and an exhaust passage85is formed by the exhaust passage80, the exhaust passage77, and the exhaust passage57.

Likewise, an exhaust passage86is formed by the exhaust passage80, the exhaust passage78, and the exhaust passage formed on the end face56side.

InFIG. 4, a ventilation chamber82is formed by the resin cover44and the heat dissipation plate42, and the ventilation chamber82and the ventilation passage74communicate with each other via the ventilation openings73.

The fan5supplies cooling air to the ventilation passage74, and the cooling air flowing in the ventilation passage74enters the ventilation chamber82via the ventilation openings73.

The cylindrical cells43are cooled by the cooling air that has entered the ventilation chamber82, and then the cooling air that has cooled the ventilation chamber82is discharged from the ventilation openings formed in the side wall67.

The battery modules11,12, and13are configured in the same manner as the battery module10.FIG. 5is a sectional view of the battery unit4taken along line V-V shown inFIG. 2. As shown inFIG. 5, the battery modules11,12, and13are respectively formed with exhaust passages90,91, and92.

FIG. 6Ais a perspective view showing the battery unit4in a state where the fixing plate14is detached.FIG. 6Bis a perspective view showing the fixing plate14detached from the battery unit4. As shown inFIG. 6A, the exhaust port58and bolt holes30and31are formed at one end face of the battery module10.

An exhaust port100and bolt holes32and33are formed at one end face of the battery module11. An exhaust passage101communicates with the exhaust port100. The exhaust passage101includes the exhaust passage90shown inFIG. 5.

An exhaust port102and bolt holes34and35are formed at one end face of the battery module12. An exhaust passage103communicates with the exhaust port102. The exhaust passage103includes the exhaust passage91shown inFIG. 5.

An exhaust port104and bolt holes36and37are formed at one end face of the battery module13. An exhaust passage105communicates with the exhaust port104. The exhaust passage105includes the exhaust passage92shown inFIG. 5.

The bolts20to27of the fixing plate14are respectively inserted into the bolt holes30to37. The bolt holes30to37are formed on their inner surfaces with threaded portions into which threaded shafts20ato27aof the bolts20to27are respectively screwed, so that the fixing plate14is fixed to one end of the battery modules10,11,12, and13.

When, for example, an internal short circuit or the like occurs in the cylindrical cell43in the battery module10, gas from the cylindrical cell43passes through the exhaust passage85and is ejected from the exhaust port58.

In this event, the gas is ejected from the exhaust port58in an ejection direction D1. Likewise, when an internal short circuit or the like occurs in the cylindrical cell in the battery module11,12, or13, gas passes through the exhaust passage101,103, or105and is ejected from the exhaust port100,102, or104in an ejection direction D2, D3, or D4.

FIG. 7is an exploded perspective view showing the fixing plate14. As shown inFIG. 7, the fixing plate14includes a plate-like fixing member body140and cover members141and142.

The fixing member body140is disposed in front of the exhaust ports58,100,102, and104in the ejection directions D1, D2, D3, and D4and formed in a plate-like shape. The fixing member body140has an opposing surface110(surface) facing the battery modules10,11,12, and13and an outer surface111located on the outer side of the battery unit4. The opposing surface110and the outer surface111are arranged in a thickness direction TD of the fixing member body140.

The opposing surface110of the fixing member body140is formed with a groove portion115and a groove portion116. The groove portion115and the groove portion116are each formed to extend from the upper end face side to the lower end face side of the fixing member body140. The groove portion115and a groove portion116are defined by inner surfaces of the fixing member body140.

The cover members141and142are formed in a plate-like shape and attached to the opposing surface110.

The cover member141is formed with an exhaust port120at a portion located in front of the exhaust port58in the ejection direction D1and with an exhaust port121at a portion located in front of the exhaust port100in the ejection direction D2. The exhaust port120is formed on the upper end side of the cover member141, while the exhaust port121is formed on the lower end side of the cover member141.

The cover member141is disposed to close an opening of the groove portion115, so that an exhaust passage130is defined in the fixing plate14by the cover member141and the inner surfaces of the groove portion115.

When the fixing plate14is fixed to the battery modules10to13, the exhaust port120(hole portion) of the cover member141and the exhaust port58of the battery module10communicate with each other. Consequently, the exhaust passage85of the battery module10and the exhaust passage130of the fixing plate14communicate with each other via the exhaust ports58and120.

Likewise, the exhaust port121of the cover member141and the exhaust port100of the battery module11communicate with each other, so that the exhaust passage101and the exhaust passage130communicate with each other via the exhaust ports100and121.

Further, exhaust ports123and124of the cover member142and the exhaust ports102and104communicate with each other, so that an exhaust passage131of the fixing plate14and the exhaust passages103and105communicate with each other.

FIG. 8is a perspective view showing the fixing plate14as viewed from the outer surface111side. As shown inFIG. 8, the fixing member body140includes a base146fixed to the bottom surface of the battery case3and a plate-like plate145formed on an upper surface of the base146.

A protruding portion147and a protruding portion148are formed on a surface on the outer surface111side of the plate145. The protruding portions147and148are formed to bulge outward from the outer surface111, so that the groove portions115and116are respectively formed by the protruding portions147and148.

The base146is formed with an exhaust port150(second exhaust port). The exhaust port150is formed at the outer surface111of the fixing member body140. A duct (not shown) is connected to the exhaust port150, and the duct communicates with the outside of the vehicle2. The exhaust port150communicates with the exhaust passage130and the exhaust passage131. The fixing plate15shown inFIG. 2is configured in the same manner as the fixing plate14.

FIG. 9is a sectional view showing the exhaust passage130and a peripheral configuration thereof. As shown inFIG. 9, when gas is ejected from the exhaust port58of the battery module10, the gas passes through the exhaust port120and impinges on the inner surface of the groove portion115.

Then, the gas that has entered the exhaust passage130passes through the exhaust port150shown inFIG. 8and is discharged to the outside of the electric power storage device1. The duct (not shown) is connected to the exhaust port150, so that the gas passes through the duct and is discharged to the outside of the vehicle2.

Herein, when the gas ejected from the exhaust port58of the battery module10impinges on the inner surface of the groove portion115, the fixing member body140receives a load in a direction away from the battery module10.

On the other hand, the fixing plate14is provided primarily for coupling the battery modules10,11,12, and13to each other and for fixing the coupled battery modules10,11,12, and13to the bottom surface of the battery case3.

Since the battery modules10,11,12, and13are heavy in weight, when a centrifugal force or the like is applied during the travel of the vehicle2, a large load is applied to the fixing plate14.

Therefore, the fastening force by the fixing members such as the bolt20is large, so that the fixing member body140is firmly fixed to the battery module10and so on.

Since, in this way, the fixing member body140is firmly fixed to the battery module10and so on, even when the load is applied from the gas ejected from the exhaust port58of the battery module10, the fixing member body140is prevented from being detached from the battery module10and so on.

In this way, even when gas is ejected from the cylindrical cell43in the battery module10, the gas can be satisfactorily discharged to the outside of the vehicle2, and further, since it is not necessary to newly provide a fixing member for fixing the fixing member body140, an increase in size of the electric power storage device1is prevented.

InFIG. 9, a stepped portion155is formed along the opening edge of the groove portion115. The stepped portion155is formed in an annular shape. The cover member141is fitted to the stepped portion155and is fixed to the stepped portion155with an adhesive or the like. In this way, since the exhaust passage130is formed by disposing the cover member141in the opening of the groove portion115, the surface area of the groove portion115located in the exhaust passage130is greater than that of the cover member141. Therefore, the gas that has entered the exhaust passage130mainly hits on the fixing member body140. As a result, hitting of the gas on the cover member141is suppressed and thus the load applied to the cover member141is suppressed to be small. Consequently, even when the cover member141is fixed to the fixing member body140with the adhesive or the like, the cover member141is prevented from being misaligned.

Likewise, even when gas is ejected from the exhaust port of the battery module11,12, or13, the gas can be discharged to the outside of the vehicle2, and further, the fixing member body140can be prevented from coming off the battery module11,12, or13.

Herein, assuming that gas ejected from the exhaust port58of the battery module10impinges on the cover member141, the cover member141receives a load from the gas in a direction so as to be pressed against the opposing surface110of the fixing member body140. Therefore, even when the gas impinges on the cover member141, the load is unlikely to be applied in a direction in which the cover member141is detached from the fixing member body140. Accordingly, the cover member141can be fixed to the fixing member body140with the adhesive or the like, so that it is possible to prevent an increase in size of the electric power storage device1and to simplify the assembly process of the electric power storage device1. Like the cover member141, the cover member142can also be fixed to the fixing member body140with the adhesive or the like.

Herein, the cover member141is made of an insulating material such as a resin. Therefore, the battery module10and the fixing member body140are prevented from being electrically connected to each other via the cover member141.

FIG. 10is a sectional view showing the bolt20and a peripheral configuration thereof. As shown inFIG. 10, the bolt20has a head portion20bdisposed on the outer surface111side of the fixing member body140and the threaded shaft20aconnected to the head portion20b. A leading end portion of the threaded shaft20ais screwed into the bolt hole31.

An interposition member165is disposed between the head portion20band the outer surface111of the fixing member body140. Further, an interposition member166is disposed between the opposing surface110of the fixing member body140and the battery module10.

The interposition member165includes a metal plate170, an insulating member171, and a metal plate172, and the insulating member171is disposed between the metal plate170and the metal plate172. Therefore, the insulation between the head portion20band the fixing member body140is ensured.

Likewise, the interposition member166includes a metal plate173, an insulating member174, and a metal plate175, and the insulating member174is disposed between the metal plate173and the metal plate175.

Therefore, the fixing member body140and the battery module10are prevented from directly contacting each other and prevented from being electrically connected to each other.

Herein, the interposition member165, the fixing member body140, and the interposition member166are respectively formed with through-holes into which the threaded shaft20ais inserted. The inner diameter of each through-hole is greater than a diameter of the threaded shaft20asuch that the threaded shaft20ais prevented from contacting an inner peripheral surface of each through-hole. The fixing member body140includes a metal plate160and insulating coating films161and162covering surfaces of the metal plate160.

In this way, the insulation between the battery module10and the fixing member body140(the metal plate160) is ensured, and further, the insulation between the bolt20fixed to the battery module10and the fixing member body140(the metal plate160) is also ensured. Likewise, with respect to the other bolts21to27, interposition members are disposed between the fixing member body140and head portions of the bolts21to27and between the fixing member body140and the battery modules10,11,12, and13.

FIG. 11is a sectional view showing a modification of the cover member141. In the cover member141shown inFIG. 11, a thin film portion180(film portion) is formed between the exhaust port58and the exhaust passage130. That is, the cover member141has a hole portion that is open at a side surface facing the exhaust port58, and the hole portion includes a bottom portion at a position entering the cover member141from the side surface. The bottom portion is formed by the thin film portion180. Therefore, in a normal state, the exhaust passage130and the exhaust port58of the battery module10do not communicate with each other.

Accordingly, it is possible to prevent the foreign matter outside the vehicle2from entering the battery module10via the exhaust passage130.

Then, when an internal short circuit occurs in the cylindrical cell43in the battery module10so that gas is ejected from the exhaust port58of the battery module10and impinges on the thin film portion180, the thin film portion180is melted. This is because when gas is ejected from the cylindrical cell43due to an internal short circuit or the like, the temperature of the gas is very high. Then, when the thin film portion180is melted, the gas from the cylindrical cell43enters the exhaust passage130, flows in the exhaust passage130, and is discharged to the outside of the vehicle2.

As described above, in the present disclosure, the exhaust passage130and the exhaust port58of the battery module10being in communication with each other is not an essential configuration in the normal state.

In the above-described embodiment, the cover member141is fixed to the fixing member body140with the adhesive or the like, but the cover member141is not necessarily fixed to the fixing member body140. For example, the cover member141may be fixed to the battery module10and may be pressed against the fixing member body140by the fastening force of the bolt20and so on. In the above-described embodiment, the electric power storage device1including the plurality of battery modules10to13has been described, but the number of battery modules may alternatively be one. When the number of battery modules is one, the fixing plates14and15are fixed to the end faces of the single battery module and further fixed to the bottom surface of the battery case3, so that the single battery module is fixed to the battery case3by the fixing plates14and15.

Further, while the fixing plates14and15are disposed at the end faces of the battery modules, the fixing plates14and15are not necessarily disposed at the end faces of the battery modules. That is, since the fixing plates14and15are members for fixing the battery modules to the battery case3, the fixing plates14and15may be disposed at any position such as near the middle of the battery modules.

The embodiment disclosed herein is for illustrative purposes only and should not be construed as being limitative in any aspect. In the embodiment disclosed herein, the exhaust passage is formed by providing the groove portion to the fixing member body, but an exhaust passage may alternatively be formed by providing a groove portion to the cover member. The scope of the present disclosure is defined by the claims, not by the description described above, and is intended to include all changes within the meaning and range of equivalents of the claims.