JP2018018657A - Battery module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a battery module capable of inhibiting working pressure of a releasing valve from becoming higher than a designed value and securing excellent heat dissipation.SOLUTION: A battery module 1 includes a releasing valve 12 for releasing pressure in a housing space S to the outside when the inner pressure of a housing 5 reaches a threshold. The releasing valve 12 includes: an opening 13 provided in the housing 5; a rubber-made valve body 15 arranged on the outer surface of the housing 5 so as to close the opening 13; and a cover 16 which has a ventilation port 19 communicated with the opening 13 and is mounted on the housing 5 in a state where the valve body 15 is energized to the outer surface of the housing 5. At the open edge 13a of the opening 13, an annular protrusion 14 is provided, and in the valve body 15, a metallic fitting member 20 fitted to the protrusion 14 is provided.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a battery module.

  In a battery module in which a nickel hydride rechargeable battery or the like is modularized, the internal pressure of the casing may increase due to the generation of hydrogen gas in the casing. Therefore, in such a battery module, in order to prevent the casing from being damaged due to an excessive increase in the internal pressure, an open valve that releases the pressure in the casing to the outside when the internal pressure exceeds a certain threshold value. Is provided.

  For example, in the sealed alkaline storage battery described in Patent Document 1, a return-type open valve is attached to the top of a metal casing. The release valve is constituted by a rubber valve body having hydrogen permeability and a support member for holding the valve body. In this storage battery, when the internal pressure of the housing rises, the rubber valve body is deformed, and the internal gas is released from the gap formed between the valve body and the housing. Further, when the internal pressure of the housing is lowered due to the release of the internal gas, the shape of the rubber valve body is restored and the housing is sealed again.

JP 2005-332767 A

  In the open valve attached to the conventional battery module described above, for example, when the open valve has not been operated for a long period of time, the rubber valve element sticks to the housing due to factors such as aging. It is possible. When the valve body sticks to the housing, the pressure required to open the valve body increases, and the operating pressure of the open valve may be higher than the set value. Further, in the battery module, if the state in which the internal pressure of the housing is increased due to generation of gas or the like continues, there is a possibility that the output is reduced or the life is shortened. For this reason, it is also important to give the battery module itself a certain heat dissipation property and suppress an increase in the internal pressure of the housing.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a battery module that can suppress the operating pressure of an open valve from becoming higher than a set value and can ensure good heat dissipation. To do.

  A battery module according to one aspect of the present invention includes a housing having a housing space therein, a laminate of electrode plates, a laminated body cell disposed in the housing space together with an electrolyte, and an internal pressure of the housing being a threshold value. An opening valve that releases the pressure in the housing space to the outside when the pressure reaches the opening, and the opening valve is made of rubber disposed on the outer surface of the housing so as to close the opening. And a cover attached to the housing in a state where the valve body is biased to the outer surface of the housing, and the opening edge of the opening has an annular shape. Convex portions are provided, and the valve body is provided with a metal fitting member that fits into the convex portions.

  In this battery module, in the open valve, the rubber valve body is urged against the annular convex portion provided at the opening edge of the housing. For this reason, compared with the case where a convex part is not provided, the contact area of a valve body and a housing | casing is suppressed, and sticking of the valve body to a housing | casing can be suppressed. By suppressing sticking of the valve body, it is possible to suppress the operating pressure of the open valve from becoming higher than the set value. Further, in this battery module, a metal fitting member is provided on the valve body, and the valve body is attached to the casing by fitting the fitting member to the convex portion. Therefore, a fitting member functions as a heat mass and can ensure favorable heat dissipation.

  The housing may be made of resin. The sticking of the valve body is likely to occur between the resin housing and the rubber valve body. Therefore, by providing an annular convex portion at the opening edge of the housing as described above and suppressing the contact area between the valve body and the housing, fluctuations in the operating pressure of the open valve can be suitably suppressed.

  Further, a metal plate may be disposed around the convex portion at the opening edge of the opening, and the fitting member of the valve body and the metal plate may be connected. In this case, the function as a heat mass of the fitting member is reinforced by the metal plate. Therefore, the heat dissipation of the battery module is further improved.

  Further, the casing is formed by arranging a partition unit in which a laminate cell and a partition are combined, and a current collector plate for connecting adjacent laminate cells sandwiching the partition is disposed in the partition, and the valve body The fitting member and the current collector plate may be connected. In this case, the function as a heat mass of the fitting member is reinforced by the current collector plate. Therefore, the heat dissipation of the battery module is further improved.

  ADVANTAGE OF THE INVENTION According to this invention, it can suppress that the operating pressure of an open valve becomes higher than a design value, and can ensure favorable heat dissipation.

It is a schematic sectional drawing of the battery module which concerns on 1st Embodiment. It is a principal part expanded sectional view of FIG. It is a principal part expanded sectional view of the battery module which concerns on 2nd Embodiment. It is a principal part expanded sectional view of the battery module which concerns on 3rd Embodiment.

Hereinafter, preferred embodiments of a battery module according to one aspect of the present invention will be described in detail with reference to the drawings.
[First Embodiment]

  FIG. 1 is a schematic cross-sectional view of a battery module according to an embodiment. The battery module 1 is obtained by modularizing a nickel hydride rechargeable battery used as a battery of a vehicle such as an automobile. As shown in the figure, the battery module 1 is configured by arranging a plurality of partition units 4 each formed by combining one stacked body cell 3 with one partition 2. The partition units 4 and 4 are coupled to each other by, for example, welding, and thereby the housing 5 of the battery module 1 is configured. As the welding, for example, ultrasonic welding using a thermoplastic resin, welding using a heat welding film, or the like is used.

  The housing 5 has a substantially rectangular parallelepiped shape that is flat in the arrangement direction of the partition units 4 as a whole, and has an accommodation space S partitioned by the partition walls 2. The housing 5 (the partition wall 2 constituting the housing 5) is made of, for example, resin. Examples of the resin material include PP, PPS, and modified PPE. In each housing space S of the housing 5, the laminated body cell 3 and the electrolytic solution are housed. Examples of the electrolytic solution include alkaline solutions such as concentrated potassium hydroxide aqueous solution.

  The partition 2 constituting the partition unit 4 has, for example, a horizontally long rectangular shape in plan view. A thick frame portion 6 is provided at an edge portion on one side of the partition wall 2. Further, a current collector plate 7 made of metal is provided inside the partition wall 2 by insert molding. The current collector plates 7 are provided separately from each other on one side and the other side in the width direction of the partition wall A (the depth direction in FIG. 1). One edge of the current collector plate 7 is a protruding portion 7 a that protrudes from the upper edge of the partition wall 2. The partition wall 2 is formed with window portions 8 on one side and the other side in the width direction. A part of the current collector plate 7 in the partition wall 2 is an exposed portion 7 b exposed from the window portion 8.

  The laminated body cell 3 is comprised by the positive electrode, the negative electrode, and the separator arrange | positioned between the positive electrode and the negative electrode. Examples of the positive electrode active material constituting the positive electrode include nickel hydroxide. Moreover, as a negative electrode active material which comprises a negative electrode, a hydrogen storage alloy is mentioned, for example. The separator is formed in a bag shape, for example. Examples of the material for forming the separator include a porous film made of a polyolefin resin such as polyethylene (PE) and polypropylene (PP), a woven fabric or a non-woven fabric made of polypropylene, polyethylene terephthalate (PET), methylcellulose and the like. In addition, a separator is not restricted to a bag shape, You may use a sheet-like thing.

  In the present embodiment, the positive electrode is included in a bag-shaped separator so that the positive electrode tab is exposed, and the stacked body cell 3 is formed by a stacked body in which the positive electrode with the separator and the negative electrode are alternately stacked. Yes. In the stacked body cell 3, the positive electrode tab group 9 and the negative electrode tab group 10 are arranged apart from each other in the width direction (the depth direction in FIG. 1). The stacked cells 3 and 3 adjacent to each other across the partition wall 2 are arranged so that the positions of the positive electrode tab group 9 and the negative electrode tab group 10 are reversed.

  In one partition unit 4, the positive electrode tab group 9 of the stacked body cell 3 is formed by connecting the protruding portions 7 a and 7 a of the current collector plate 7 with the connection member 11, thereby stacking the stacked body cell in one adjacent partition unit 4. 3 negative electrode tab groups 10. Further, in one partition unit 4, the negative electrode tab group 10 of the stacked body cell 3 is formed by connecting the protruding portions 7 a and 7 a of the current collector plate 7 with the connection member 11, thereby stacking the other adjacent partition unit 4. The positive electrode tab group 9 of the body cell 3 is connected. Thereby, each laminated body cell 3 is in the state electrically connected in series. For example, welding is used for the connection between the positive electrode tab group 9 and the current collector plate 7 and the connection between the negative electrode tab group 10 and the current collector plate 7. Examples of the welding form include resistance seam welding and laser penetration welding.

  In the battery module 1 described above, as shown in FIG. 1, when the internal pressure of the housing 5 exceeds a certain threshold in order to prevent the housing 5 from being damaged due to an excessive increase in internal pressure. An open valve 12 is provided to release the pressure in the housing space S of the housing 5 to the outside. As shown in FIG. 2, when the release valve 12 is installed in the battery module 1, an opening 13 connected to the accommodation space S is provided at the upper edge of the partition wall 2 of each partition unit 4. In the partition wall 2, an annular convex portion 14 is provided on the opening edge 13 a of the opening 13. In the present embodiment, the convex portion 14 has an annular shape, and the inner diameter of the convex portion 14 matches, for example, the inner diameter of the opening 13.

  The release valve 12 includes a rubber valve body 15 and a cover 16 attached to the outer surface of the housing 5. The valve body 15 is formed, for example, in a cylindrical shape from rubber such as ethylene propylene diene rubber (EPDM) or fluorine rubber, and is disposed on the outer surface of the housing 5 so as to close the opening 13. The outer diameter of the valve body 15 is larger than the outer diameter of the convex portion 14.

  A metal fitting member 20 that is fitted to the convex portion 14 is provided on one end surface of the valve body 15. The fitting member 20 has an annular shape, for example. The inner diameter of the fitting member 20 matches the outer diameter of the convex portion 14, and the outer diameter of the fitting member 20 matches the outer diameter of the valve body 15. The valve body 15 is attached to the partition wall 2 by fitting the fitting member 20 to the convex portion 14. In the present embodiment, the fitting member 20 is in contact with the surface of the partition wall 2 when the fitting member 20 is fitted to the convex portion 14.

  The cover 16 is made of a resin such as polyphenylene sulfide (PPS) or modified polyphenylene ether (modified PPE). The cover 16 includes a plate-like base portion 17 and a plurality of partition portions 18 provided on one surface side of the base portion 17 at intervals corresponding to the arrangement pitch of the partition walls 2. The cover 16 is fixed to the housing 5 in a state in which the front end side of each partition portion 18 is abutted against the upper end of the main surface portion of the partition wall 2 (the portion where the current collector plate 7 is insert-molded). Thereby, the arrangement space V of the valve body 15 is formed by the space surrounded by the upper edge portion of the partition wall 2, the base portion 17, and the partition portion 18. Further, the base portion 17 is provided with a vent hole 19 communicating with each arrangement space V. By attaching the cover 16, the valve body 15 in the arrangement space V is compressed by a predetermined amount between the base portion 17 and the partition wall 2 and is urged around the opening 13 in the partition wall 2.

  The open valve 12 is a so-called return type open valve with the above-described configuration. When the internal pressure of the housing 5 (in this case, the internal pressure of the accommodation space S partitioned by the partition wall 2) reaches a predetermined threshold value, the release valve 12 is deformed by the rubber valve body 15 and the opening 13 is opened. The accommodation space S, the opening 13, the arrangement space V, and the vent hole 19 communicate with each other. Thereby, the pressure in the accommodation space S is released to the outside, and the internal pressure of the housing 5 is reduced. Further, when the internal pressure of the housing 5 decreases due to the opening of the storage space S, the valve body 15 closes the opening 13 again by the urging from the cover 16, and the storage space S is closed.

  In the battery module 1 having the above configuration, the rubber valve body 15 is urged against the annular convex portion 14 provided in the opening edge portion 13 a of the housing 5 in the open valve 12. For this reason, compared with the case where the convex part 14 is not provided, the contact area of the valve body 15 and the housing | casing 5 is suppressed, and sticking of the valve body 15 to the housing | casing 5 can be suppressed. By suppressing the sticking of the valve body 15, it can suppress that the operating pressure of the open valve 12 becomes higher than a setting value. Further, in the battery module 1, a metal fitting member 20 is provided on the valve body 15, and the valve body 15 is attached to the casing by fitting the fitting member 20 to the convex portion 14. Therefore, the fitting member 20 functions as a heat mass, and good heat dissipation can be ensured.

  In the battery module 1, a rubber valve body 15 is applied to the resin casing 5. The sticking of the valve body 15 is likely to occur between the resin casing 5 and the rubber valve body 15. Therefore, as described above, by providing the annular convex portion 14 at the opening edge 13a of the housing 5 and suppressing the contact area between the valve body 15 and the housing 5, the fluctuation of the operating pressure of the release valve 12 is suitably performed. Can be suppressed.

In addition, in this embodiment, although the annular convex part 14 and the fitting member 20 were illustrated, the convex part 14 and the fitting member 20 should just be cyclic | annular, and a rectangular cyclic | annular form may be sufficient as it. Moreover, the convex part 14 and the fitting member 20 are not restricted to the structure currently formed continuously around the opening 13, either one of the convex part 14 and the fitting member 20 is the opening 13 in the range which can be fitted. The structure which is scattered around may be sufficient.
[Second Embodiment]

  FIG. 3 is an enlarged cross-sectional view of a main part of the battery module according to the second embodiment. As shown in the figure, the battery module 21 according to the second embodiment is different from the first embodiment in the configuration of the release valve 22.

  More specifically, in the battery module 21, a metal plate 23 is provided on the opening edge 13 a of the opening 13 at the upper edge of the partition wall 2. In the present embodiment, the metal plate 23 has an annular shape with an inner diameter and an outer diameter equal to the fitting member 20 on the valve body 15 side. The metal plate 23 is provided integrally with the partition wall 2 around the convex portion 14 by insert molding, for example, and is buried in the partition wall 2 so as to be flush with the outer surface of the partition wall 2. The fitting member 20 of the valve body 15 is in contact with the metal plate 23 in a state where the fitting member 20 is fitted to the convex portion 14.

According to such a configuration, since the fitting member 20 and the metal plate 23 are connected to increase the volume of the metal, the function of the fitting member 20 as a heat mass is enhanced. Therefore, the heat dissipation of the battery module 21 is further improved. In the example shown in FIG. 3, the inner diameter and the outer diameter of the metal plate 23 match the inner diameter and the outer diameter of the fitting member 20 on the valve body 15 side. The inner and outer diameters of the metal plate 23 may be changed as appropriate within the range of contact. Moreover, the metal plate 23 should just be connected with a part of fitting member 20, and is not restricted to cyclic | annular form, Other shapes, such as rectangular shape and strip | belt shape, may be sufficient.
[Third Embodiment]

  FIG. 4 is an enlarged cross-sectional view of a main part of the battery module according to the third embodiment. As shown in the figure, the battery module 31 according to the third embodiment is further different from the first embodiment in the configuration of the release valve 32.

  More specifically, in the battery module 31, the fitting member 20 on the valve body 15 side and the current collector plate 7 in the partition wall 2 are connected by a metal plate 33. The metal plate 33 is provided integrally with the partition wall 2 by, for example, insert molding, and is buried in the partition wall 2 between the current collector plate 7 and the convex portion 14 so as to be flush with the outer surface of the partition wall 2. The fitting member 20 of the valve body 15 is in contact with the metal plate 33 in a state where the fitting member 20 is fitted to the convex portion 14.

  According to such a configuration, since the fitting member 20 is connected to the metal plate 33 and the current collector plate 7 to increase the volume of the metal, the function of the fitting member 20 as a heat mass is further strengthened. Therefore, the heat dissipation of the battery module 1 is further improved. In the example shown in FIG. 4, the metal plate 33 and the current collector plate 7 are separate, but the metal plate 33 extends from the current collector plate 7 as a part of the current collector plate 7. It may be an extended part.

  The battery module laminate cell is a bipolar type in which a metal foil made of a single material having a positive electrode active material coated on one surface and a negative electrode active material coated on the other surface is laminated via a separator. There may be. In this case, “positive electrode” means “positive electrode active material layer itself”, and “negative electrode” means “negative electrode active material layer itself”.

  DESCRIPTION OF SYMBOLS 1, 21, 31 ... Battery module, 2 ... Partition, 3 ... Laminated body cell, 4 ... Partition unit, 5 ... Housing, 7 ... Current collecting plate, 12, 22, 32 ... Open valve, 13 ... Opening, 13a ... Opening edge part, 14 ... convex part, 15 ... valve body, 16 ... cover, 19 ... vent, 20 ... fitting member, 23 ... metal plate, S ... accommodating space.

Claims (4)

A housing having a housing space inside;
A laminated body cell constituted by a laminated body of electrode plates and disposed in the accommodating space together with an electrolyte; and
An open valve that releases the pressure in the housing space to the outside when the internal pressure of the housing reaches a threshold value,
The release valve is
An opening provided in the housing;
A rubber valve disposed on the outer surface of the housing so as to close the opening;
A vent that communicates with the opening, and a cover that is attached to the housing in a state in which the valve body is biased to the outer surface of the housing;
A battery module in which an annular convex portion is provided at an opening edge portion of the opening, and a metal fitting member that is fitted to the convex portion is provided in the valve body.   The battery module according to claim 1, wherein the casing is made of resin. A metal plate is disposed around the convex portion at the opening edge of the opening,
The battery module according to claim 1, wherein the fitting member of the valve body and the metal plate are connected. The casing is formed by arranging a partition unit combining the laminate cell and the partition,
In the partition, a current collector plate that connects the stacked cells adjacent to each other across the partition is disposed,
The battery module according to claim 1, wherein the fitting member of the valve body and the current collector plate are connected.

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