JP2025101067A - Battery case - Google Patents

Abstract

[Problem] To provide a battery case that can suppress an increase in internal pressure with a simple configuration. [Solution] A battery case (10) houses a battery inside when a lower case (20) and an upper case (30) are assembled, and has a flange (11) formed on its outer circumferential surface. The flange (11) has a lower flange portion (23) that protrudes outward from the lower case (20) and an upper flange portion (33) that protrudes outward from the upper case (30) and faces the lower flange portion (23). A gasket (40) is disposed between the lower flange portion (23) and the upper flange portion (33). The gasket (40) is formed with a valve portion (41) that is elastically deformable from a closed configuration that airtightly separates the interior of the battery case (10) from the outside of the battery case (10) to an open configuration that connects the interior of the battery case (10) to the outside of the battery case (10). [Selected Figure] Figure 5

Description

The present invention relates to a battery case.

The excess pressure release valve disclosed in Patent Document 1 is configured such that an inner lid with an airtight hole leading to the inside of a sealed container and an outer lid covering the inner lid, containing a dome-shaped elastic body and having an open hole to the outside world, are attached to the sealed container while being integrated, and release excess pressure inside to the outside world. This excess pressure release valve is biased by the compression caused by the dome-shaped elastic body being pressed and sandwiched between the inner lid and the outer lid that contacts the dome opening, and is capable of opening the airtight hole with excess pressure. The excess pressure release valve airtightly seals the dome top of the dome-shaped elastic body from the outside world, and has a notch at the dome opening that guides excess pressure to the release hole.

JP 2013-148126 A

When providing an internal pressure release structure such as the excessive pressure release valve of Patent Document 1 to a battery case, it is necessary to assemble various components, such as an inner lid, an outer lid, a dome-shaped elastic body, and a notch, to the battery case. This increases the number of components, raising concerns that the overall size will become larger. Therefore, there is a demand for technology that can release the internal pressure of a battery case with a simple configuration.

The present invention was developed based on the above circumstances, and aims to provide a battery case that can suppress an increase in internal pressure with a simple structure.

The battery case of the present invention comprises:
A battery case including a first case, a second case, and a gasket, a battery housed therein when the first case and the second case are assembled together, and a flange formed on an outer circumferential surface,
The flange portion is
a first flange portion extending outward from the first case;
a second flange portion that protrudes outward from the second case and faces the first flange portion,
the gasket is disposed between the first flange portion and the second flange portion,
The gasket is formed with a valve portion that is elastically deformable from a closed valve configuration that airtightly isolates the inside of the battery case from the outside of the battery case to an open valve configuration that connects the inside of the battery case to the outside of the battery case.

This configuration provides a battery case that can suppress an increase in internal pressure with a simple structure.

FIG. 1 is a perspective view showing a battery case according to a first embodiment of the present invention; A perspective view of part of the battery case flange seen from below FIG. 2, omitting the second case. Cross-section view of the battery case flange from the right side Cross-sectional view of the battery case flange from the front

[1] A battery case comprising a first case, a second case, and a gasket, a battery housed inside when the first case and the second case are assembled, and a flange formed on an outer circumferential surface,
The flange is
a first flange portion extending outward from the first case;
a second flange portion that protrudes outward from the second case and faces the first flange portion,
the gasket is disposed between the first flange portion and the second flange portion,
The gasket has a valve portion formed therein that is elastically deformable from a closed valve configuration that airtightly isolates the inside of the battery case from the outside of the battery case to an open valve configuration that connects the inside of the battery case to the outside of the battery case.

According to this configuration, when the internal pressure of the battery case is relatively low, the valve portion is maintained in a closed state that airtightly isolates the inside and outside of the battery case, thereby maintaining the airtightness of the battery case. On the other hand, when the internal pressure of the battery case increases, the valve portion elastically deforms to an open state that connects the inside and outside of the battery case, thereby suppressing the increase in internal pressure of the battery case. In addition, the valve portion is formed as part of the gasket. This allows the configuration of the battery case to be simplified compared to a configuration in which a dedicated part such as an explosion-proof valve is assembled separately from the gasket. Therefore, the battery case can suppress the increase in internal pressure with a simple configuration.

[2] The battery case described in [1], which is provided with a support member having a higher rigidity than the gasket and sandwiched between the first flange portion and the second flange portion.

With this configuration, the distance between the first flange portion and the second flange portion can be adjusted by the support member, and the valve portion can be maintained in the appropriate shape.

[3] An opening is formed in one of the first flange portion and the second flange portion at a position overlapping the gasket in the opposing direction of the first flange portion and the second flange portion,
The battery case according to claim 1 or 2, wherein the peripheral portion of the opening functions as a valve seat with which the valve portion comes into contact.

With this configuration, when the valve portion changes from a closed state to an open state, gas inside the battery case can be released to the outside through an opening formed in one of the first flange portion and the second flange portion.

[4] The valve portion has a ring shape that fits along the peripheral portion of the opening,
An outer circumferential surface of the valve portion is exposed to the inside of the battery case,
The battery case according to claim 3, wherein an inner surface of the valve portion is exposed to the outside of the battery case.

With this configuration, the valve portion is ring-shaped, which increases the rigidity of the valve portion. Therefore, even if pressure is applied to the outer peripheral surface of the valve portion, the degree of deformation of the valve portion can be stabilized.

Example 1
A first embodiment of the present invention will now be described with reference to Figures 1 to 5. In the following description, with regard to the up-down direction, the H direction in Figure 1 is defined as the upside.

(Configuration of battery case 10)
A battery case 10 according to the first embodiment is shown in FIG. 1. The battery case 10 houses a battery (not shown). The battery is, for example, a battery module composed of a plurality of battery cells. As shown in FIG. 1, the battery case 10 has, for example, a substantially rectangular shape in a plan view. The battery case 10 is attached to the underside of the vehicle body (the outer surface under the floor) in a state in which it is supported from below by, for example, a bracket (not shown). The battery case 10 may also house electrical components such as a CPU and sensors.

The battery case 10 includes a lower case 20, an upper case 30, a gasket 40, and a support member (collar) 50. The lower case 20 corresponds to an example of the "first case" of the present invention. The upper case 30 corresponds to an example of the "second case" of the present invention. The battery case 10 accommodates a battery and the like inside when the lower case 20 and the upper case 30 are assembled. For example, a battery is placed on the inner bottom surface of the lower case 20. The upper case 30 covers and closes the opening of the lower case 20. The battery case 10 has a flange 11 formed on the outer periphery. The flange 11 is provided around the entire periphery of the battery case 10.

The lower case 20 is made of, for example, a metal material (iron, aluminum, etc.). The lower case 20 has a bottom wall 21, a side wall 22, and a lower flange portion 23. The lower flange portion 23 corresponds to an example of a "first flange portion" of the present invention. The bottom wall 21 is a square plate. The side wall 22 rises from the periphery of the bottom wall 21. The lower flange portion 23 protrudes outward from the upper edge opening (upper end) of the side wall 22.

The upper case 30 is made of a metal material (iron, aluminum, etc.). The upper case 30 has a ceiling wall 31, a side wall 32, and an upper flange portion 33. The upper flange portion 33 corresponds to an example of the "second flange portion" of the present invention. The ceiling wall 31 is a square plate. The side wall 32 extends downward from the periphery of the ceiling wall 31. The upper flange portion 33 protrudes outward from the lower edge opening (lower end) of the side wall 32. The upper flange portion 33 is disposed above the lower flange portion 23. As shown in FIG. 4, the outer edge of the upper flange portion 33 is bent downward to cover the gap between the lower flange portion 23 and the upper flange portion 33 from the outside.

The flange 11 is composed of a lower flange portion 23 and an upper flange portion 33. As shown in Figures 3 to 5, the gasket 40 is disposed between the lower flange portion 23 and the upper flange portion 33. The gasket 40 is sandwiched between the upper surface of the lower flange portion 23 and the lower surface of the upper flange portion 33. The gasket 40 is in airtight contact with the lower flange portion 23 and the upper flange portion 33. The gasket 40 provides a liquid-tight seal between the lower flange portion 23 and the upper flange portion 33. The gasket 40 is made of an elastically deformable material such as rubber. The gasket 40 is annular and disposed along the entire circumference of the flange 11.

(Fixing structure of flange 11)
5, the battery case 10 further includes a plurality of bolts 61, a plurality of nuts 62, and a plurality of ring members (collars) 63. The lower flange portion 23 and the upper flange portion 33 are fixed together by fastening the bolts 61 and the nuts 62.

Lower flange portion 23 has a plurality of holes 23A formed therethrough in the vertical direction. The holes 23A are formed at equal intervals around the entire circumference of lower flange portion 23, for example at positions corresponding to the positions of bolts 61 shown in FIG. 1. As shown in FIG. 5, upper flange portion 33 also has a plurality of holes 33A formed therethrough in the vertical direction. The holes 33A are formed at positions that overlap with the holes 23A in the vertical direction.

As shown in FIG. 5, the multiple ring members 63 are sandwiched between the upper surface of the lower flange portion 23 and the lower surface of the upper flange portion 33. The ring members 63 are arranged in positions that overlap in the vertical direction with the holes 23A of the lower flange portion 23 and the holes 33A of the upper flange portion 33. As shown in FIG. 2 and FIG. 5, the ring members 63 are fitted into the holes 40A of the gasket 40, which will be described later. The ring members 63 are made of, for example, metal, resin material, etc. The ring members 63 have holes 63A that penetrate in the vertical direction.

As shown in FIG. 5, the shaft of the bolt 61 passes through the hole 23A of the lower flange portion 23, the hole 33A of the upper flange portion 33, and the hole 63A of the ring member 63 from above. A nut 62 is fastened to the shaft of the bolt 61 on the lower side of the lower flange portion 23. The lower flange portion 23, the ring member 63, and the upper flange portion 33 are sandwiched and fixed by the head of the bolt 61 and the nut 62.

As shown in FIG. 5, a groove 63B is formed on the outer circumferential surface of the ring member 63. The groove 63B is formed around the entire circumference of the hole 63A in the ring member 63. A protrusion 40B of the gasket 40, which will be described later, fits into the groove 63B.

(Internal pressure release structure)
The lower flange portion 23 is formed with a plurality of openings 24 (vent holes, air communication holes, see FIG. 2 ) for releasing the internal pressure of the battery case 10. The openings 24 are through holes that penetrate the lower flange portion 23 in the up-down direction. The openings 24 are formed at positions that overlap the gasket 40 in the opposing direction (up-down direction) of the lower flange portion 23 and the upper flange portion 33. The plurality of openings 24 are formed at equal intervals around the entire circumference of the lower flange portion 23. The openings 24 are formed between a pair of holes 23A in the lower flange portion 23. The openings 24 are formed, for example, at a midpoint between the pair of holes 23A in the lower flange portion 23. The openings 24 are circular.

As shown in FIG. 3, the gasket 40 has a hole 40A formed at a position that overlaps in the vertical direction with the hole 23A of the lower flange portion 23 and the hole 33A of the upper flange portion 33. A ring member 63 is fitted into the hole 40A. A protrusion 40B that protrudes inward around the entire circumference of the inner circumferential surface of the hole 40A is formed on the inner circumferential surface. The protrusion 40B is fitted into a groove 63B of the ring member 63.

As shown in FIG. 4, the gasket 40 further includes a valve portion 41, a recess 42, and a locking hole 43. The valve portion 41, the recess 42, and the locking hole 43 are formed as a single component that is inseparable from the other portions of the gasket 40. The valve portion 41 functions as an explosion-proof valve and a check valve. The valve portion 41 is subjected to the internal pressure of the battery case 10.

The valve portion 41 is formed at a position (above the opening 24) corresponding to the opening 24 in the lower flange portion 23. The valve portion 41 faces the opening 24. The valve portion 41 is elastically deformable from a closed valve configuration (configuration shown in FIG. 4) that airtightly separates the inside of the battery case 10 (also referred to as the internal space) from the outside of the battery case 10 (also referred to as the external space) to an open valve configuration that connects the internal space of the battery case 10 to the external space of the battery case 10.

The valve portion 41 has a circular ring shape that fits along the edge of the opening 24. Specifically, the valve portion 41 is cylindrical with an axis that fits along the vertical direction. The inner diameter of the valve portion 41 is larger than the diameter of the opening 24. The valve portion 41 is shaped to protrude downward in the gasket 40. The tip (lower end) of the valve portion 41 has an inclined surface that slopes downward toward the inside of the valve portion 41.

The tip of the valve portion 41 is in contact with the upper surface of the lower flange portion 23. Specifically, the tip of the valve portion 41 is in contact with the peripheral portion 25 of the opening 24 of the lower flange portion 23. More specifically, the entire circumference of the tip of the valve portion 41 is in annular contact with the entire circumference of the peripheral portion 25. The peripheral portion 25 functions as a valve seat with which the valve portion 41 comes into contact. The valve portion 41 is elastically deformed in the vertical direction by being sandwiched in a compressed state between the lower flange portion 23 and the upper flange portion 33.

The recess 42 is formed around the outer periphery of the valve portion 41 in the gasket 40. The recess 42 is open downward and inward (toward the internal space of the battery case 10). The bottom surface (ceiling surface) of the recess 42 is located above the center of the gasket 40 in the vertical direction. The bottom surface of the recess 42 is located at the same position in the vertical direction as the inner bottom surface (ceiling surface) of the valve portion 41. A support member 50, which will be described later, is attached to the recess 42.

As shown in FIG. 4, the locking hole 43 is formed in the recess 42 on the inner side (the inner space side of the battery case 10) of the valve portion 41. The locking hole 43 is a hole that penetrates the gasket 40 in the vertical direction. A locking piece 53 of the support member 50, which will be described later, is fitted into the locking hole 43.

The outer peripheral surface of the valve portion 41 (more specifically, the portion that does not contact the support member 50 described below) is exposed to the internal space of the battery case 10. The inner peripheral surface of the valve portion 41 is exposed to the external space of the battery case 10.

(Configuration of Support Member 50)
As shown in Fig. 4, the support member (collar) 50 is sandwiched between the lower flange portion 23 and the upper flange portion 33. The support member 50 is in the shape of a ring surrounding the valve portion 41. The support member 50 is made of, for example, a resin material. The support member 50 is made of a material that is harder (more rigid) than the gasket 40. The support member 50 is fitted into the recess 42 of the gasket 40 from below.

As shown in FIG. 4, the support member 50 has a bottom 51, an outer edge 52, and a locking piece 53. The bottom 51 has a shape that corresponds to the recess 42 of the gasket 40, and is a ring shape with a constant thickness in the vertical direction. The bottom 51 is fitted into the recess 42. The inner surface of the bottom 51 contacts the outer surface of the valve portion 41. The outer surface of the bottom 51 contacts the inner surface of the recess 42.

As shown in FIG. 3, the outer edge portion 52 protrudes downward from the bottom portion 51 except for the inner edge portion. The inner peripheral surface of the outer edge portion 52 is spaced apart from the outer peripheral surface of the valve portion 41. The outer peripheral surface of the outer edge portion 52 contacts the inner peripheral surface of the recess 42. The tip (lower end) of the outer edge portion 52 contacts the upper surface of the lower flange portion 23.

As shown in FIG. 4, the locking piece 53 protrudes upward from the upper surface of the bottom 51. The locking piece 53 is located slightly outward from the inner edge of the bottom 51. The locking piece 53 is, for example, elongated and extends along the inner edge of the bottom 51. The locking piece 53 is fitted into the locking hole 43 of the gasket 40. The tip (upper end) of the locking piece 53 is in contact with the lower surface of the upper flange portion 33.

(Function of Battery Case 10)
For example, when gas is generated in the internal space of the battery case 10, the internal pressure of the battery case 10 increases. For example, gas is generated from the battery due to an abnormality of the battery in the battery case 10. In such a case, the pressure (internal pressure) received by the outer peripheral surface of the valve portion 41 becomes greater than the pressure (external pressure) received by the inner peripheral surface of the valve portion 41. Then, the valve portion 41 elastically deforms inward from the closed valve form (form shown in FIG. 4 ) to a form (open valve form) in which a gap is generated between the tip (lower end) of the valve portion 41 and the peripheral portion 25 of the opening 24. The valve portion 41 deforms uniformly in the entire circumferential direction, for example, because the internal pressure is applied over the entire circumferential direction of the outer peripheral surface. The gas in the internal space is discharged from the gap between the tip (lower end) of the valve portion 41 and the peripheral portion 25 of the opening 24, thereby suppressing the rise in the internal pressure of the battery case 10. For example, after the internal pressure of the battery case 10 is reduced, the valve portion 41 changes from the open state to the closed state, again airtightly isolating the internal space and the external space of the battery case 10.

The tip (lower end) of the valve portion 41 is formed with an inclined surface (a surface that slopes downward toward the inside of the valve portion 41), and since the tip of such valve portion 41 is in contact with the lower flange portion 23, water and the like are less likely to enter the internal space of the battery case 10 through the opening 24 and the valve portion 41.

By changing the diameter of the valve portion 41, the thickness of the valve portion 41 (the width between the outer peripheral surface and the inner peripheral surface), the inclination angle of the inclined surface at the tip, etc., the internal pressure when changing from the closed valve state to the open valve state can be adjusted.

(Effects of Example 1)
The battery case 10 of the first embodiment includes a lower case (first case) 20, an upper case (second case) 30, and a gasket 40. The battery case 10 accommodates a battery inside when the lower case 20 and the upper case 30 are assembled, and has a flange 11 formed on the outer circumferential surface. The flange 11 has a lower flange portion (first flange portion) 23 that protrudes outward in the lower case 20, and an upper flange portion (second flange portion) 33 that protrudes outward in the upper case 30 and faces the lower flange portion 23. The gasket 40 is disposed between the lower flange portion 23 and the upper flange portion 33. The gasket 40 is formed with a valve portion 41 that is elastically deformable from a closed valve form that airtightly isolates the inside (internal space) of the battery case 10 from the outside (external space) of the battery case 10 to an open valve form that communicates the inside of the battery case 10 with the outside of the battery case 10.

According to this configuration, when the internal pressure of the battery case 10 is relatively low, the valve portion 41 is maintained in a closed state that airtightly isolates the inside (internal space) of the battery case 10 from the outside (external space), thereby maintaining the airtightness of the battery case 10. On the other hand, when the internal pressure of the battery case 10 increases, the valve portion 41 elastically deforms to an open state that connects the inside of the battery case 10 with the outside, thereby suppressing the increase in the internal pressure of the battery case 10. In addition, the valve portion 41 is formed as a part of the gasket 40. This simplifies the configuration of the battery case 10 compared to a configuration in which a dedicated part such as an explosion-proof valve is assembled separately from the gasket 40. Therefore, the battery case 10 can suppress the increase in internal pressure with a simple configuration.

The battery case 10 of the first embodiment includes a support member 50 that is more rigid than the gasket 40 and is sandwiched between the lower flange portion 23 and the upper flange portion 33 .
According to this configuration, the distance between the lower flange portion 23 and the upper flange portion 33 can be adjusted by the support member 50, and the valve portion 41 can be maintained in an appropriate shape.

In the battery case 10 of Example 1, an opening 24 is formed in one of the lower flange portion 23 and the upper flange portion 33 at a position overlapping the gasket 40 in the opposing direction (up-down direction) of the lower flange portion 23 and the upper flange portion 33. A peripheral portion 25 of the opening 24 functions as a valve seat with which the valve portion 41 comes into contact.
According to this configuration, when the valve portion 41 is transformed from a closed valve form to an open valve form, gas within the battery case 10 can be released to the outside through an opening 24 formed in one of the lower flange portion 23 and the upper flange portion 33.

In the battery case 10 of Example 1, the valve portion 41 has a ring shape that fits along the peripheral edge portion 25 of the opening 24. The outer peripheral surface of the valve portion 41 is exposed to the inside of the battery case 10. The inner peripheral surface of the valve portion 41 is exposed to the outside of the battery case 10.
According to this configuration, since the valve portion 41 is ring-shaped, it is possible to increase the rigidity of the valve portion 41. Therefore, even if pressure is applied to the outer circumferential surface of the valve portion 41, it is possible to stabilize the degree of deformation of the valve portion 41.

<Other Examples>
The present invention is not limited to the embodiments described above and illustrated in the drawings, and the following embodiments are also included within the technical scope of the present invention.
In the first embodiment, the gasket 40 is annular and arranged along the entire circumference of the flange 11. However, the gasket 40 may be composed of a plurality of divided bodies arranged along a part of or the entire circumference of the flange 11.
In the first embodiment, the valve portion 41 is ring-shaped. However, the valve portion 41 may be in another shape, such as a flat plate or a cylindrical shape.
In the first embodiment, the opening 24 is circular. However, the opening 24 may be rectangular or have another shape.
In the first embodiment, the valve portion 41 is configured to contact the peripheral portion 25 of the opening 24, but it may be configured to directly block the opening 24 or to block the space between the outer edge portion of the lower flange portion 23 and the outer edge portion of the upper flange portion 33.
In the first embodiment, the opening 24 is formed in the lower flange portion 23, but it may be formed in the upper flange portion 33. Specifically, the opening 24 may be formed at a position overlapping the gasket 40 in the opposing direction (up-down direction) of the lower flange portion 23 and the upper flange portion 33. In this case, the valve portion 41, the recess 42, and the locking hole 43 are formed in a configuration that is upside down in the gasket 40.

10: Battery case 11: Flange 20: Lower case (first case)
21: Bottom wall 22: Side wall 23: Lower flange portion (first flange portion)
23A: Hole 24: Opening 25: Peripheral portion 30: Upper case (second case)
31: Ceiling wall 32: Side wall 33: Upper flange portion (second flange portion)
33A: Hole 40: Gasket 40A: Hole 40B: Protrusion 41: Valve portion 42: Recess 43: Locking hole 50: Support member 51: Bottom portion 52: Outer edge portion 53: Locking piece 61: Bolt 62: Nut 63: Ring member 63A: Hole 63B: Groove

Claims (4)

A battery case including a first case, a second case, and a gasket, a battery housed therein when the first case and the second case are assembled together, and a flange formed on an outer circumferential surface thereof,
The flange is
a first flange portion extending outward from the first case;
a second flange portion that protrudes outward from the second case and faces the first flange portion,
the gasket is disposed between the first flange portion and the second flange portion,
The gasket has a valve portion formed therein that is elastically deformable from a closed valve configuration that airtightly isolates the inside of the battery case from the outside of the battery case to an open valve configuration that connects the inside of the battery case to the outside of the battery case. The battery case according to claim 1, further comprising a support member that is more rigid than the gasket and is sandwiched between the first flange portion and the second flange portion. an opening is formed in one of the first flange portion and the second flange portion at a position overlapping the gasket in a direction in which the first flange portion and the second flange portion face each other;
The battery case according to claim 1 or 2, wherein a peripheral portion of the opening functions as a valve seat with which the valve portion comes into contact. the valve portion has a ring shape that fits along the periphery of the opening,
An outer circumferential surface of the valve portion is exposed to the inside of the battery case,
The battery case according to claim 3 , wherein an inner circumferential surface of the valve portion is exposed to an outside of the battery case.

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