Vehicle battery pack

Abstract

To provide a highly safe vehicle battery pack that reduces the effects of melting due to thermal runaway and the like.SOLUTION: A vehicle battery pack includes a battery case, one or more battery cells, and a thermal insulator. Each of the one or more battery cells includes a safety structure for suppressing an increase in internal pressure by releasing gas. The battery case has a structure that defines an internal space. The battery cells are disposed in the internal space of the battery case. The thermal insulator is disposed in the internal space of the battery case so as to cover above the one or more battery cells, including above the safety structure in a state of being fixed to the battery case in an area other than above the safety structure.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a vehicle battery pack. [Background technology]

[0002] Vehicle battery packs equipped with thermal insulation materials have been known (see, for example, Patent Document 1). For example, Patent Document 1 discloses a battery box for an electric vehicle in which a thermal insulation layer is provided on an upper cover that covers a case body that houses the battery pack.

[0003] In addition, Patent Document 2 discloses a technology for an electricity storage device that includes a heat shield plate above an electricity storage element, in which the heat shield plate is locked to a resin spacer unit. The spacer units are provided alternately with the electricity storage element. The electricity storage element is arranged so as to be surrounded by two spacer units. The heat shield plate is locked by a locking portion provided on the upper wall of the spacer unit. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2021 / 192620 [Patent Document 2] Japanese Patent Application Laid-Open No. 2017-152161 Summary of the Invention [Problem to be solved by the invention]

[0005] In the above-mentioned conventional technology, the insulating material (specifically, the insulating material layer and the heat shield plate) is supported by a resin material. The resin material supports the insulating material at a position where it is directly hit by high-temperature gas released from a valve (i.e., a release valve or safety valve) for releasing the internal pressure of the battery. Therefore, if high-temperature gas is released from the battery due to thermal runaway, the resin material may melt due to the heat, causing the insulating material and surrounding components to fall off toward the battery body located underneath.

[0006] Therefore, according to one aspect of the present disclosure, it is desirable to provide a vehicle battery pack that is highly safe and that reduces the effects of melting due to thermal runaway and the like. [Means for solving the problem]

[0007] According to one aspect of the present disclosure, there is provided a vehicle battery pack including a battery case, one or more battery cells, and a thermal insulator, each of which includes a safety structure for suppressing an increase in internal pressure by releasing gas.

[0008] The battery case has a structure that defines an interior space. The battery cells are disposed in the interior space of the battery case. The heat insulating material is disposed in the interior space of the battery case so as to cover the upper part of one or more battery cells.

[0009] According to one aspect of the present disclosure, the heat insulating material is fixed to the battery case in an area of the battery case excluding an area above the safety structure, and the heat insulating material covers an area above one or more battery cells, including an area above the safety structure.

[0010] In a vehicle battery pack configured in this manner, the thermal impact on the battery case caused by gas released upward from the safety structure can be reduced by the thermal insulation material. Because the thermal insulation material is fixed to the battery case in an area other than above the safety structure, it is possible to prevent the portion that fixes the thermal insulation material to the battery case from being destroyed (melted, etc.) by heat from the gas released from the safety structure.

[0011] Therefore, according to one aspect of the present disclosure, it is possible to provide a vehicle battery pack that is highly safe and that reduces the effects of melting due to thermal runaway and the like.

[0012] According to one aspect of the present disclosure, the battery case may include a fixing structure in the interior space for clamping and fixing the insulating material. The insulating material may be fixed to the battery case by the fixing structure.

[0013] According to one aspect of the present disclosure, the battery case may include a central portion that houses one or more battery cells and a flange portion located on the periphery of the central portion. In this case, the heat insulating material may be fixed to the battery case by the flange portion. By fixing the heat insulating material in this manner, the high-temperature gas emitted from the safety structure does not directly hit the fixed portion between the heat insulating material and the battery case, thereby providing a highly safe vehicle battery pack that is less susceptible to melting due to thermal runaway and the like.

[0014] According to one aspect of the present disclosure, the battery case may include an upper member and a lower member. The upper member may include an upper central portion recessed from bottom to top and an upper flange portion located on the periphery of the upper central portion. The lower member may include a lower central portion recessed from top to bottom and a lower flange portion located on the periphery of the lower central portion.

[0015] The one or more battery cells may be housed in a space surrounded by an upper central portion and a lower central portion, the space being sealed by a sealing member provided between the upper flange portion and the lower flange portion. The insulating material may be fixed to the battery case through the sealing member. This type of fixation allows the insulating material to be fixed to the battery case by effectively utilizing the sealing member.

[0016] According to one aspect of the present disclosure, the structure defining the interior space of the battery case may include an upper wall, a lower wall, and side walls that surround one or more battery cells. The thermal insulator may be fixed to the battery case at the side walls. By fixing the thermal insulator to the battery case at the side walls, it is possible to reduce the possibility of the fixed portions becoming hot and melting due to the effect of high-temperature gas released from the safety structure. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 1 is a perspective view of a battery pack according to a first embodiment. [Figure 2] FIG. 2 is a cross-sectional view of the battery pack taken along line II-II. [Figure 3] FIG. 2 is an enlarged cross-sectional view of a portion of the battery pack. [Figure 4] FIG. [Figure 5] FIG. 2 is an explanatory diagram of a safety valve of a battery cell. [Figure 6] FIG. 6A is a cross-sectional view of a battery pack according to a second embodiment, and FIG. 6B is a cross-sectional view of a battery pack according to a third embodiment. [Figure 7] FIG. 7A is a cross-sectional view of a battery pack according to a fourth embodiment, and FIG. 7B is a cross-sectional view of a battery pack according to a fifth embodiment. [Figure 8] FIG. 13 is a cross-sectional view of a battery pack according to a sixth embodiment. [Figure 9] FIG. 10 is a perspective view of a heat insulating material according to a sixth embodiment. [Figure 10] FIG. 10A is a cross-sectional view of a battery pack according to the seventh embodiment, and FIG. 10B is an enlarged cross-sectional view of a portion of the battery pack according to the seventh embodiment. [Figure 11] FIG. 13 is a partially see-through top view of a battery pack according to an eighth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0018] Exemplary embodiments of the present disclosure will now be described with reference to the drawings. [First embodiment] The battery pack 1 of this embodiment shown in Figures 1 and 2 includes a plurality of battery cells 11 and a battery case 20 that houses the plurality of battery cells 11. This battery pack 1 is used, for example, as a vehicle battery pack. Hereinafter, the plurality of battery cells 11 will be collectively referred to as a battery cell group 10. Reference numeral 10 indicates a group of battery cells 11. In Figure 2, some, but not all, of the battery cells 11 included in the battery cell group 10 are indicated by dashed lines.

[0019] The battery pack 1 is mounted, for example, under a vehicle. The vehicle is, for example, an electric vehicle. An electric vehicle is a vehicle that runs using electrical energy stored in a plurality of battery cells 11 as all or part of its power. Examples of electric vehicles include electric vehicles, plug-in hybrid vehicles, and hybrid vehicles.

[0020] The battery case 20 forms the outer shape of the battery pack 1. The battery case 20 includes a generally rectangular parallelepiped central portion 21 that houses a plurality of battery cells 11, i.e., a battery cell group 10, and a flange portion 25 located on the periphery of the central portion 21.

[0021] The battery case 20 includes an upper member 30 and a lower member 40. Fig. 2 shows a cross section taken along line II-II of the battery case 20 shown in Fig. 1, but a cross section perpendicular to the II-II cross section of the battery case 20 also has a shape similar to that of the II-II cross section.

[0022] The battery case 20 is constructed by overlapping and joining an upper member 30 and a lower member 40. Examples of joining include mechanical joining using bolts or the like, chemical joining using adhesives or the like, and metallurgical joining using welding or the like.

[0023] A seal member 50 for closing the central portion 21 is provided inside the flange portion 25. The upper member 30 and the lower member 40 can be joined together by adhesive bonding via the seal member 50, for example.

[0024] 2, the upper member 30 includes an upper central portion 31 recessed from bottom to top, and an upper flange portion 35 located on the periphery of the upper central portion 31. The lower member 40 includes a lower central portion 41 recessed from top to bottom, and a lower flange portion 45 located on the periphery of the lower central portion 41.

[0025] The central portion 21 of the battery case 20 is made up of an upper central portion 31 and a lower central portion 41. The flange portion 25 of the battery case 20 is made up of an upper flange portion 35 and a lower flange portion 45.

[0026] The battery case 20 defines an internal space by the upper member 30 and lower member 40 having such shapes. The internal space includes a storage space for the battery cell group 10. The storage space for the battery cell group 10 corresponds to the space surrounded by the upper central portion 31 and the lower central portion 41. The battery cell group 10 is stored inside the central portion 21, i.e., in the space surrounded by the upper central portion 31 and the lower central portion 41. The battery cell group 10 is arranged at a predetermined position inside the central portion 21.

[0027] The upper central portion 31 of the upper member 30 includes an upper wall 31A and upper side walls 31B. The upper wall 31A is a horizontally extending wall in the shape of a roughly rectangular plate, and is configured to cover from above the storage space for the battery cell group 10. The upper side walls 31B are disposed so as to extend downward from the edges of the upper wall 31A, specifically from the four sides of the upper wall 31A.

[0028] The upper flange portion 35 extends horizontally from the end of the upper side wall 31B opposite the end connected to the upper wall 31A in a direction away from the upper wall 31A. When viewed from above, the upper flange portion 35 is provided so as to surround the four sides of the upper wall 31A. In other words, the upper flange portion 35 has a frame shape that surrounds the upper central portion 31. The upper central portion 31 of the upper member 30 is configured so as to present a shape that is recessed from bottom to top relative to the upper flange portion 35 by the upper wall 31A and the upper side wall 31B.

[0029] The upper member 30 is made of, for example, metal. The upper member 30 is manufactured by, for example, press-forming a metal plate. By this press-forming, the upper central portion 31 and the upper flange portion 35 are integrally formed. Examples of the metal plate include a stainless steel plate and a plated steel plate.

[0030] The lower central portion 41 of the lower member 40 includes a lower wall 41A and lower side walls 41B. The lower wall 41A is a horizontally extending wall in the shape of a roughly rectangular plate, and is configured to cover from below the storage space for the battery cell group 10. The lower side walls 41B are arranged to extend upward from the edges of the lower wall 41A, specifically from the four sides of the lower wall 41A.

[0031] The lower flange portion 45 extends horizontally from the end of the lower wall 41B opposite the end connected to the lower wall 41A in a direction away from the lower wall 41A. When viewed from above, the lower flange portion 45 is provided so as to surround the four sides of the lower wall 41A. In other words, the lower flange portion 45 has a frame shape that surrounds the lower central portion 41. The lower central portion 41 of the lower member 40 is configured so as to present a shape that is recessed from top to bottom relative to the lower flange portion 45 by the lower wall 41A and the lower wall 41B.

[0032] The lower member 40 is made of, for example, metal. The lower member 40 is produced, for example, by press-forming a metal plate. This press-forming process results in the lower central portion 41 and the lower flange portion 45 being integrally formed. Examples of metal plates include stainless steel plates and plated steel plates. However, because the lower member 40 is not directly affected by heat from the battery cell group 10, it does not have to be made of metal and can also be made of resin.

[0033] The sealing member 50 is disposed between the upper flange portion 35 and the lower flange portion 45, and is configured to close the storage space for the battery cell group 10 that is surrounded by the central portion 21. The sealing member 50 may be configured with an adhesive for bonding the lower surface of the upper flange portion 35 and the upper surface of the lower flange portion 45 together.

[0034] The sealing member 50 may be formed of, for example, an adhesive that has fluidity before application and solidifies and loses fluidity after application, thereby bonding multiple adjacent members. Examples of the sealing member 50 include a urethane-based adhesive, an epoxy-based adhesive, and a silicone-based adhesive.

[0035] As shown in Figures 2 and 3, a heat insulating material 60 is provided in the internal space of the battery case 20, covering the battery cell group 10 from above. The heat insulating material 60 is made of a material with low thermal conductivity that can maintain a certain shape and has electrical insulation properties. The heat insulating material 60 may be made of, for example, an inorganic material. The heat insulating material 60 may be made of a fibrous material, a foamed material, or a material in which granular or fibrous material is solidified into a sheet shape with resin or the like.

[0036] Similar to the upper member 30, the heat insulating material 60 has a central portion 61 recessed from bottom to top and flange portions 65 located on the periphery of the central portion 61 (see FIG. 4). The central portion 61 has an upper wall 61A in the shape of a generally rectangular plate, and side walls 61B extending downward from the four sides of the upper wall 61A.

[0037] Fig. 4 shows a simplified example of the shape of the thermal insulator 60. Fig. 4 shows, for simplicity, the thermal insulator 60 having a flat upper wall 61A, but it may also be understood that the upper wall 61A of the thermal insulator 60 is curved upward as shown in Fig. 2. The curvature may be formed by configuring the upper wall 61A of the thermal insulator 60 to be larger than the upper wall 31A of the battery case 20, and bending the thermal insulator 60 when attaching the thermal insulator 60 to the battery case 20.

[0038] 2 and 3, according to this embodiment, the flange portion 65 of the heat insulating material 60 is fixed to the battery case 20 via the seal member 50. As a result, the heat insulating material 60 is disposed in the internal space of the battery case 20 so as to cover the upper side of the battery cell group 10.

[0039] The heat insulating material 60 is not fixed above the battery cell group 10, and furthermore, is not fixed to the center portion 21 of the battery case 20 in which the battery cell group 10 is housed, but is placed above the battery cell group 10. In this case, the heat insulating material 60 is placed at a position spaced below the upper wall 31A of the battery case 20 so as not to come into contact with the upper wall 31A. The heat insulating material 60 is also placed at a position spaced above the battery cell group 10 so as not to come into contact with the battery cell group 10.

[0040] The flange portion 65 of the heat insulating material 60 is embedded in the adhesive, for example, while the adhesive forming the seal member 50 is in a fluid state. As a result, the heat insulating material 60 is fixed in a state where the flange portion 65 is embedded in the seal member 50.

[0041] As described above, a feature of this embodiment is that the heat insulating material 60 is not fixed to the storage space for the battery cell group 10, particularly not above the battery cell group 10, but is fixed at the flange portion 25 located on the side of the storage space. Furthermore, the heat insulating material 60 does not come into contact with the upper wall 31A of the battery case 20 above the battery cell group 10. Even if high-temperature gas is released from the battery cell group 10 due to thermal runaway of the battery cell group 10, the fixed portion is not directly exposed to the high-temperature gas.

[0042] As shown in Fig. 5, the battery cell 11 has a safety valve 11A at the top. The safety valve 11A functions as a safety structure that suppresses an increase in internal pressure due to gas generated during thermal runaway of the battery cell 11 by releasing the gas. The safety valve 11A is also called a release valve or explosion-proof valve. In the example shown in Fig. 5, the battery cell 11 has the safety valve 11A between a pair of terminals T1 and T2. When the internal pressure of the battery cell 11 increases, high-temperature gas is released upward from the safety valve 11A.

[0043] The heat insulating material 60 is installed inside the battery case 20 so as to cover the upper part of the safety valve 11A in order to prevent the battery case 20 from becoming too hot due to exposure to the high-temperature gas released from the battery cell 11, and to prevent components inside and outside the battery case 20 from melting or being destroyed.

[0044] In this embodiment, the heat insulating material 60 is fixed in the internal space of the battery case 20 by a flange portion 25 that is laterally spaced from the storage space for the battery cell group 10. The lateral direction here is the direction perpendicular to the up-down direction, and corresponds to the horizontal direction and the side.

[0045] Therefore, according to this embodiment, when high-temperature gas is released from the safety valve 11A due to thermal runaway of the battery cell 11, the fixed portion of the heat insulating material 60 to the battery case 20 can be prevented from being directly exposed to the high-temperature gas and becoming too hot, and it is possible to prevent the fixed portion from being damaged by the high temperature and the heat insulating material 60 from falling off inside the battery case 20 due to the damage of the fixed portion. Furthermore, it is possible to prevent heat from the high-temperature gas from being conducted to the battery case 20 or vehicle components through the fixed portion.

[0046] According to this embodiment, the heat insulating material 60 is not in contact with the battery case 20 above the battery cell group 10, and therefore it is possible to suppress heat conduction to the battery case 20 due to contact between the heat insulating material 60 and the battery case 20. As a result, the battery pack 1 of this embodiment can suppress adverse effects on the battery pack 1 due to thermal runaway of the battery cells 11 and adverse effects on vehicle components located around the battery pack 1.

[0047] [Second embodiment] Next, the configuration of the battery pack 101 of the second embodiment will be described with reference to Fig. 6A. The battery pack 101 of the second embodiment has the same configuration as the battery pack 1 of the first embodiment, except that the shape and fixing method of the heat insulating material 160 are different from those of the first embodiment.

[0048] The following selectively describes the configuration of the battery pack 101 of the second embodiment that is different from that of the first embodiment. In the battery pack 101 of the second embodiment, the configurations that are assigned the same reference numerals as those of the battery pack 1 of the first embodiment may be understood to be the same configurations as those of the battery pack 1 of the first embodiment unless additional explanation is provided.

[0049] 6A, the battery pack 101 of this embodiment includes a heat insulator 160 having a different shape from that of the first embodiment. This heat insulator 160 has a configuration similar to that of the heat insulator 60 of the first embodiment, with the flange portion 65 removed. The heat insulator 160 includes an upper wall 161A having a generally rectangular plate shape and side walls 161B extending downward from the four sides of the upper wall 161A, and has a rectangular box-like outer shape with an opening on the bottom.

[0050] As in the first embodiment, the heat insulating material 160 is disposed in the internal space of the battery case 20 at a position spaced below the upper wall 31A so as to cover the upper part of the battery cell group 10, but is not fixed to the sealing member 50. A fixing part 120 for fixing the heat insulating material 160 is provided inside the battery case 20 as a fixing structure. The fixing part 120 is made of, but not limited to, metal or resin, for example.

[0051] The fixing part 120 is configured to sandwich the side wall 161B of the heat insulating material 160 between the fixing part 120 and the upper wall 31B of the battery case 20. With this configuration, the heat insulating material 160 is fixed to the upper wall 31B of the battery case 20 by the fixing part 120.

[0052] The fixing component 120 may be, for example, a rectangular frame-shaped component extending along the four sides of the top wall 31A of the battery case 20 when viewed from above. For example, the fixing component 120 is installed so as to be fitted inside the top central portion 31 with the side wall 161B of the heat insulating material 160 sandwiched between the fixing component 120 and the inner surface of the top central portion 31 of the battery case 20. In this way, the fixing component 120 can be fixed to the battery case 20 by its elasticity.

[0053] According to another example, a notch may be provided in the side wall 161B of the heat insulating material 160 for directly joining the fixing component 120 to the upper wall 31B of the battery case 20. The fixing component 120 may be adhered to the battery case 20 with an adhesive or the like at a portion facing the upper wall 31B of the battery case 20 through the notch in the heat insulating material 160. Alternatively, the fixing component 120 may be fixed to the battery case 20 with a bolt, welding, or the like.

[0054] According to this embodiment, of the upper wall 31A, upper side wall 31B, lower wall 41A, and lower side wall 41B of the battery case 20 that surround the storage space for the battery cell group 10, the heat insulating material 160 is fixed to the upper side wall 31B that is not located above the battery cell group 10.

[0055] 6A, the battery cell group 10 is fixed to a limited central region of the space surrounded by the central portion 21 on a plane perpendicular to the up-down direction. That is, there are gaps in the horizontal direction between the battery cell group 10 and the upper wall 31B and the lower wall 41B. The fixing component 120 is provided in this gap.

[0056] 6A, most or all of the fixing component 120 is located to the side of the battery cell group 10, at a position lower than the upper ends of the battery cells 11. Therefore, in this embodiment as well, it is possible to prevent the fixing portion of the heat insulating material 160 and the battery case 20 from being directly exposed to the high-temperature gas released from the safety valve 11A during thermal runaway, and it is possible to prevent the fixing component 120 from being destroyed by high temperature and the heat insulating material 160 from falling off. It is also possible to prevent heat from being transferred from the high-temperature gas from the heat insulating material 160 to the battery case 20 through the contact portion between the heat insulating material 160 and the battery case 20.

[0057] As a result, according to this embodiment, similar to the first embodiment, it is possible to provide a highly safe battery pack 101 that is suppressed from being affected by melting or the like due to thermal runaway.

[0058] [Third embodiment] Next, the configuration of a battery pack 201 of a third embodiment will be described with reference to Fig. 6B. The battery pack 201 of the third embodiment has the same configuration as the battery pack 101 of the second embodiment, except that the shape and fixing position of the heat insulating material 260 are different from those of the second embodiment.

[0059] The following selectively describes the configuration of the battery pack 201 of the third embodiment that is different from that of the second embodiment. In the battery pack 201 of the third embodiment, the configurations that are assigned the same reference numerals as those of the battery pack 101 of the second embodiment may be understood to be the same configurations as those of the battery pack 101 of the second embodiment unless additional explanation is provided.

[0060] 6B, the heat insulating material 260 of this embodiment has a generally rectangular plate-shaped upper wall 261A and side walls 261B, similar to the heat insulating material 160 of the second embodiment. However, the side walls 261B extend downward from the four sides of the upper wall 261A longer than in the second embodiment.

[0061] As in the first and second embodiments, this heat insulating material 260 is disposed below the upper wall 31A at a position spaced apart from the upper wall 31A so as to cover the upper part of the battery cell group 10, but is not fixed to the seal member 50. A fixing part 220 for fixing the heat insulating material 260 is provided inside the battery case 20 as a fixing structure. The fixing part 220 is made of, but not limited to, metal or resin, for example.

[0062] The fixing part 220 is configured to sandwich the side wall 261B of the heat insulating material 260 between itself and the lower wall 41B of the battery case 20. With this configuration, the heat insulating material 260 is fixed to the lower wall 41B of the battery case 20 by the fixing part 220.

[0063] The fixing part 220 is configured in a rectangular frame shape, similar to the fixing part 120 of the second embodiment. The fixing part 220 is fixed to the lower wall 41B of the battery case 20 in a state in which the side wall 261B of the heat insulating material 260 is sandwiched between the fixing part 220 and the lower wall 41B of the battery case 20, in the same manner as the fixing part 120 of the second embodiment. The fixing part 220 fixes the heat insulating material 260 to the battery case 20 by sandwiching the side wall 261B of the heat insulating material 260 between the fixing part 220 and the lower wall 41B of the battery case 20.

[0064] According to this embodiment, of the top wall 31A, upper side wall 31B, bottom wall 41A, and bottom wall 41B of the battery case 20 that surround the storage space for the battery cell group 10, the heat insulating material 160 is fixed to the bottom wall 41B that is not located above the battery cell group 10. The fixing component 220 is not located above the battery cells 11, but is arranged at a position lower than the upper ends of the battery cells 11. The fixing component 220 is arranged to the side of the battery cell group 10, particularly in the gap between the battery cell group 10 and the bottom wall 41B, with a gap between them.

[0065] With this arrangement, the heat insulating material 260 is fixed to the battery case 20 in an area of the battery case 20 excluding the area above the safety valve 11A of the battery cell group 10, and covers the area above the battery cell group 10, including the area above the safety valve 11A.

[0066] According to this embodiment, as in the first and second embodiments, it is possible to prevent the fixed portion of the insulating material 260 to the battery case 20 from being directly exposed to the high-temperature gas released from the safety valve 11A during thermal runaway, thereby preventing destruction of the fixed part 220 and heat conduction from the high-temperature gas to the battery case 20 through the contact portion between the insulating material 260 and the battery case 20.

[0067] [Fourth embodiment] Next, the configuration of a battery pack 301 of the fourth embodiment will be described with reference to Fig. 7A. The battery pack 301 of the fourth embodiment has the same configuration as the battery pack 101 of the second embodiment, except that the method of fixing the heat insulating material 160 is different from that of the second embodiment.

[0068] The following selectively describes the configuration of the battery pack 301 of the fourth embodiment that is different from that of the second embodiment. In the battery pack 301 of the fourth embodiment, the configurations that are assigned the same reference numerals as those of the battery pack 101 of the second embodiment may be understood to be the same configurations as those of the battery pack 101 of the second embodiment unless additional explanation is provided.

[0069] 7A, the battery pack 301 of this embodiment includes the same heat insulating material 160 as in the second embodiment in the internal space of the battery case 20. This heat insulating material 160 is fixed to the battery case 20 by a fixing part 320 provided inside the battery case 20 at a position spaced below the upper wall 31A so as to cover the upper part of the battery cell group 10. The fixing part 320 is made of, but not limited to, metal or resin, for example.

[0070] The fixing component 320 is configured as a fixing structure so as to sandwich the side wall 161B of the heat insulating material 160 between itself and the upper wall 31B of the battery case 20. In this way, the heat insulating material 160 is fixed to the upper wall 31B of the battery case 20 by the fixing component 320.

[0071] The fixing part 320 has a rectangular frame-shaped side wall 321A configured in the same manner as the fixing part 120, and a bottom wall 321B extending laterally from the lower end of the side wall 321A toward the outside of the central part 21, and has an outer shape in which the side wall 321A and the bottom wall 321B are integrated.

[0072] The fixing component 320 is fixed to the battery case 20 in the internal space of the battery case 20 by joining between the upper surface of the lower wall 321B and the lower surface of the upper flange portion 35 of the battery case 20. Examples of joining include joining by adhesive and joining by welding.

[0073] The fixing component 320 is fixed to the upper flange portion 35 so as to be able to sandwich the side wall 161B of the heat insulating material 160 between the side wall 321A and the upper side wall 31B of the battery case 20. With the side wall 161B fixed by the fixing component 320, the heat insulating material 160 is arranged so as to cover the upper side of the battery cell group 10 in the battery case 20.

[0074] According to this embodiment, similar to the second embodiment, the heat insulating material 160 is fixed to the upper wall 31B, which is not located above the battery cell group 10. As shown in Fig. 7A, most or all of the fixing component 320 is located to the side of the battery cell group 10, at a position lower than the upper ends of the battery cells 11. Therefore, according to this embodiment, similar to the second embodiment, it is possible to provide a highly safe battery pack 301 that is suppressed from the effects of melting due to thermal runaway and the like.

[0075] [Fifth embodiment] Next, the configuration of a battery pack 401 of the fifth embodiment will be described with reference to Fig. 7B. The battery pack 401 of the fifth embodiment has the same configuration as the battery pack 201 of the third embodiment, except that the method of fixing the heat insulating material 260 is different from that of the third embodiment.

[0076] The following selectively describes the configuration of the battery pack 401 of the fifth embodiment that is different from that of the third embodiment. In the battery pack 401 of the fifth embodiment, the configurations that are assigned the same reference numerals as those of the battery pack 201 of the third embodiment may be understood to be the same configurations as those of the battery pack 201 of the third embodiment unless additional explanation is provided.

[0077] 7B, the battery pack 401 of this embodiment includes the same heat insulating material 260 as in the third embodiment in the internal space of the battery case 20. This heat insulating material 260 is fixed to the battery case 20 on the side of the battery cell group 10 by a fixing portion 420 serving as a fixing structure provided inside the battery case 20. The fixing portion 420 is made of, but is not limited to, metal or resin, for example.

[0078] The fixing portion 420 is provided on the lower wall 41B of the battery case 20, on the side of the battery cell group 10. The fixing portion 420 is integrally formed with the lower member 40, or the fixing portion 420 is joined to the lower member 40 as a fixing part.

[0079] The fixing portion 420 has a rectangular frame-shaped side wall 421A configured in the same manner as the fixing component 220, and a bottom wall 421B extending laterally from the lower end of the side wall 421A toward the outside of the central portion 21, and has an outer shape in which the side wall 421A and the bottom wall 421B are integrated.

[0080] The fixing portion 420 is configured to sandwich the side wall 261B of the heat insulating material 260 between the side wall 421A and the lower wall 41B of the battery case 20. In this way, the heat insulating material 260 is fixed to the lower wall 41B of the battery case 20. With the side wall 261B fixed by the fixing portion 420, the heat insulating material 260 is disposed in the internal space of the battery case 20 at a position spaced below the upper wall 31A so as to cover the top of the battery cell group 10.

[0081] According to this embodiment, similar to the third embodiment, the heat insulating material 260 is fixed to the lower wall 41B, which is not located above the battery cell group 10. As shown in Fig. 7B, the fixing portion 420 is located at a position lower than the upper ends of the battery cells 11, spaced apart from the battery cell group 10, and to the side of the battery cell group 10. Therefore, similar to the third embodiment, according to this embodiment, it is possible to provide a highly safe battery pack 401 that is suppressed from the effects of melting due to thermal runaway and the like.

[0082] [Sixth embodiment] Next, the configuration of a battery pack 501 of the sixth embodiment will be described with reference to Figures 8 and 9. The battery pack 501 of the sixth embodiment has the same configuration as the battery pack 101 of the second embodiment, except that the shape and fixing method of the heat insulating material 560 are different from those of the second embodiment.

[0083] The following selectively describes the configuration of the battery pack 501 of the sixth embodiment that is different from that of the second embodiment. In the battery pack 501 of the sixth embodiment, the configurations that are assigned the same reference numerals as those of the battery pack 101 of the second embodiment may be understood to be the same configurations as those of the battery pack 101 of the second embodiment unless additional explanation is provided.

[0084] 8, a battery pack 501 of this embodiment includes a heat insulating material 560 having a shape similar to the heat insulating material 160 of the second embodiment in the internal space of the battery case 20. The heat insulating material 560 is fixed to the battery case 20 below the upper wall 31A by a fixing part 520 as a fixing structure provided inside the battery case 20 so as to cover the upper part of the battery cell group 10.

[0085] The fixing part 520 is fixed to the battery case 20 with a gap between it and the upper wall 31A. However, it may also be fixed to the battery case 20 in contact with the upper wall 31A. The fixing part 520 is made of, but is not limited to, metal or resin, for example.

[0086] Similar to the heat insulating material 160 of the second embodiment, the heat insulating material 560 has an upper wall 561A having a roughly rectangular plate shape and side walls 561B extending downward from the four sides of the upper wall 561A, and has a rectangular box-like outer shape with an opening on the bottom.

[0087] However, the downward length of side wall 561B is slightly shorter than that of side wall 161B of thermal insulation material 160. Thermal insulation material 560 further has notches 561C in side wall 561B at positions corresponding to the four corners of top wall 561A. That is, notches 561C are provided at the corners of side wall 561B that constitute the four corners of box-shaped thermal insulation material 560, as shown in FIG. 9. Notches 561C separate side walls 561B extending downward from the four sides of top wall 561A into individual sides.

[0088] The fixing part 520 is configured to support the heat insulating material 560 from below. The fixing part 520 is further configured to sandwich the side wall 561B of the heat insulating material 560 between itself and the upper wall 31B of the battery case 20. As a result, the heat insulating material 560 is fixed to the upper wall 31B of the battery case 20 by the fixing part 520. Optionally, the fixing part 520 may be configured to sandwich the upper wall 561A of the heat insulating material 560 between itself and the upper wall 31A of the battery case 20. This sandwiching can be achieved by disposing the fixing part 520 in a position close to the upper wall 561A.

[0089] As shown in Figures 8 and 9, fixing part 520 has a rectangular frame-shaped side wall 521A configured in the same manner as fixing part 120, and an upper wall 521B extending laterally from the upper end of side wall 521A toward the inside of central part 21, and has an outer shape in which side wall 521A and upper wall 521B are integrated.

[0090] The heat insulating material 560 is fixed to the internal space of the battery case 20 by the fixing part 520 with its upper wall 561A facing the upper wall 31A of the battery case 20 and supported from below by the upper wall 521B of the fixing part 520, and further with its side wall 561B sandwiched between the side wall 521A of the fixing part 520 and the upper wall 31B of the battery case 20.

[0091] The fixing component 520 supports the heat insulating material 560 from below with the upper wall 521B, and is fixed to the upper wall 31B of the battery case 20 with the side wall 521A sandwiching the side wall 561B of the heat insulating material 560 between the fixing component 520 and the upper wall 31B of the battery case 20. Specifically, the fixing component 520 is joined to the upper wall 31B of the battery case 20 at four corners of the rectangular frame-shaped side wall 521A that correspond to the positions where the notches 561C of the heat insulating material 560 are arranged. The joining can be achieved by, for example, but not limited to, adhesive bonding or welding.

[0092] As explained in the second embodiment, the battery cell group 10 is fixed to a limited central region of the space surrounded by the central portion 21 on a plane perpendicular to the up-down direction. The fixing component 520 is partially located above the battery cell group 10, but the side wall 521A of the fixing component 520, which essentially fixes the heat insulating material 560 to the battery case 20, is not located above the battery cell group 10. There is a lateral gap between the battery cell group 10 and the upper wall 31B and the lower wall 41B. The side wall 521A of the fixing component 520 is located above this gap. Furthermore, the entire fixing component 520 is not located above the safety valve 11A of the battery cell group 10.

[0093] With this arrangement, the heat insulating material 560 is fixed to the battery case 20 in an area of the battery case 20 excluding the area above the safety valve 11A of the battery cell group 10, and covers the area above the battery cell group 10, including the area above the safety valve 11A.

[0094] According to this embodiment, as in the other embodiments described above, it is possible to prevent the fixed portion of the heat insulating material 260 to the battery case 20 from being directly exposed to the high-temperature gas from the safety valve 11A, and it is possible to prevent the fixing part 520 from being destroyed by high temperature and causing the heat insulating material 560 to fall off. In addition, it is possible to prevent heat conduction from the high-temperature gas to the battery case 20 through the contact portion between the heat insulating material 260 and the battery case 20.

[0095] [Seventh embodiment] Next, the configuration of a battery pack 601 of the seventh embodiment will be described with reference to Figures 10A and 10B. The battery pack 601 of the seventh embodiment has the same configuration as the battery pack 1 of the first embodiment, except that the shape and fixing method of the heat insulating material 660 are different from those of the first embodiment.

[0096] The following selectively describes the configuration of the battery pack 601 of the seventh embodiment that is different from that of the first embodiment. In the battery pack 601 of the seventh embodiment, the configurations that are assigned the same reference numerals as those of the battery pack 1 of the first embodiment may be understood to be the same configurations as those of the battery pack 1 of the first embodiment unless additional explanation is provided.

[0097] The heat insulating material 660 of this embodiment is a rectangular sheet-shaped heat insulating material having a size corresponding to the top wall 31A of the battery case 20. The heat insulating material 660 is arranged so as to cover almost the entire inner surface of the top wall 31A of the battery case 20 that faces the battery cell group 10.

[0098] The heat insulating material 660 is adhered to the inner surface of the upper wall 31A in areas near the four sides of the upper wall 31A that are not located above the battery cell group 10, using a material that is the same as or different from the material used for the sealing member 50 (in other words, an adhesive). As described above, there are lateral gaps between the battery cell group 10 and the upper wall 31B and lower wall 41B. The heat insulating material 660 is adhered to the inner surface of the upper wall 31A above these gaps.

[0099] The adhesive may be, for example, an epoxy adhesive. Figures 10A and 10B show that the heat insulating material 660 is fixed to the inner surface of the upper wall 31A of the battery case 20 through an adhesive joint 620 formed by solidification of the adhesive.

[0100] According to one example, the heat insulating material 660 is arranged so as not to come into contact with the upper wall 31A of the battery case 20 except for the area corresponding to the adhesive portion 620, that is, so as to form a gap between the heat insulating material 660 and the upper wall 31A.

[0101] According to this embodiment, as in the other embodiments described above, it is possible to prevent the portion of the heat insulating material 660 that is fixed to the battery case 20 from being directly exposed to high-temperature gas from the safety valve 11A.

[0102] [Eighth embodiment] Next, the configuration of a battery pack 701 of the eighth embodiment will be described with reference to Fig. 11. The battery pack 701 of the eighth embodiment has the same configuration as the battery pack 601 of the seventh embodiment, except that the shape and fixing method of the heat insulating material 760 are different from those of the seventh embodiment.

[0103] The following selectively describes the configuration of the battery pack 701 of the eighth embodiment that is different from that of the seventh embodiment. In the battery pack 701 of the eighth embodiment, the configurations that are assigned the same reference numerals as those of the battery pack 601 of the seventh embodiment may be understood to be the same configurations as those of the battery pack 601 of the seventh embodiment unless additional explanation is provided.

[0104] The insulating material 760 of this embodiment, like the seventh embodiment, is a rectangular sheet-shaped insulating material of a size corresponding to the inner surface of the upper wall 31A of the battery case 20, and is arranged so as to cover almost the entire inner surface of the upper wall 31A of the battery case 20 facing the battery cell group 10, and optionally so as to be in contact with the inner surface of the upper wall 31A.

[0105] The heat insulating material 760 is adhered to the inner surface of the top wall 31A of the battery case 20 with an adhesive in an area excluding the area above the safety valve 11A. The adhesive may be a tape. In Fig. 11, an adhesive surface 720 of the heat insulating material 760 that is adhered to the top wall 31A of the battery case 20 is indicated by hatching. The adhesive surface 720 may be understood to be in the hatched area.

[0106] 11 is a top view of the battery pack 701, showing the upper wall 31A in a see-through manner. The heat insulating material 760 is not adhered to the upper wall 31A above the safety valve 11A, but covers the upper wall 31A from below. That is, the heat insulating material 760 is also present above the safety valve 11A, which is not hatched in FIG.

[0107] 11, the heat insulating material 760 is adhered to the upper wall 31A of the battery case 20 so as to avoid the safety valve 11A. This creates a gap, i.e., a highly insulating air layer, between the heat insulating material 760 and the upper wall 31A above the safety valve 11A.

[0108] Therefore, according to this embodiment, it is possible to prevent the high-temperature gas released from the safety valve 11A from traveling through the insulating material 760 and the adhesive surface 720 to the upper wall 31A, and further from being transmitted to components adjacent to the upper wall 31A.

[0109] [Other embodiments] The present disclosure is not limited to the above-described embodiment, and various modifications can be made. For example, the present disclosure can be applied to a battery pack including one or more battery cells 11.

[0110] In the above embodiment, taking into consideration that the area above the safety valve 11A will be exposed to high-temperature gas in the event of thermal runaway, the insulating material 60, 160, 260, 560, 660, 760 is not bonded to the upper wall 31A above the safety valve 11A, but a highly insulating air layer is provided between them to suppress heat conduction to the upper wall 31A and suppress heat conduction through the upper wall 31A, for example, heat conduction to the outside of the battery packs 1, 101, 201, 301, 401, 501, 601, 701.

[0111] Furthermore, by limiting the fixed portions of the heat insulating material 60, 160, 260, 560, 660, 760, it is possible to suppress heat conduction from the heat insulating material 60, 160, 260, 560, 660, 760 to the battery case 20. Furthermore, it is possible to suppress localized temperature increases due to the portions of the heat insulating material 60, 160, 260, 560, 660, 760 that are not fixed to the battery case 20 shaking due to vehicle vibration.

[0112] Furthermore, the fixing portions of the heat insulating materials 60, 160, 260, 560, 660, 760 may become too hot, which may destroy the fixing portions and cause the heat insulating materials 60, 160, 260, 560, 660 or the structure of the fixing portions to fall off, which can suppress adverse effects.

[0113] Therefore, the present disclosure may incorporate alternative insulation shapes and fastening methods that can achieve one or more of these effects.

[0114] The function of one component in the above embodiments may be distributed among multiple components. The functions of multiple components may be integrated into one component. Part of the configuration of the above embodiments may be omitted. At least part of the configuration of the above embodiments may be added to or substituted for the configuration of another of the above embodiments. All aspects included in the technical idea identified from the wording of the claims are embodiments of the present disclosure. [Explanation of symbols]

[0115] 1,101,201,301,401,501,601,701...battery pack, 10...battery cell group, 11...battery cell, 11A...safety valve, 20...battery case, 21...center portion, 25...flange portion, 30...upper member, 31...upper center portion, 31A...upper wall, 31B...upper wall, 35...upper flange portion, 40...lower member, 41...lower center portion, 41A...lower wall, 41B...lower wall, 45...lower flange portion, 50...sealing member, 60 , 160, 260, 560, 660, 760...insulating material, 61...center portion, 61A, 161A, 261A, 561A...upper wall, 61B, 161B, 261B, 561B...side wall, 65...flange portion, 120, 220, 320, 520...fixing parts, 321A, 421A, 521A...side wall, 321B, 421B...lower wall, 420...fixing portion, 521B...upper wall, 561C...notch, 620...adhesive portion, 720...adhesive surface.

Claims

1. A vehicle battery pack, a battery case having a structure that defines an interior space; one or more battery cells disposed in the internal space of the battery case; a heat insulating material disposed in the internal space of the battery case so as to cover an upper portion of the one or more battery cells; each of the one or more battery cells has a safety structure for suppressing an increase in internal pressure by releasing gas; The heat insulating material covers the upper part of the one or more battery cells, including the upper part of the safety structure, in a state where the heat insulating material is fixed to the battery case in an area of the battery case excluding the area above the safety structure. Vehicle battery pack.

2. 2. The vehicle battery pack according to claim 1, the battery case includes a fixing structure in the internal space for clamping and fixing the heat insulating material; The heat insulating material is fixed to the battery case by the fixing structure. Vehicle battery pack.

3. 2. The vehicle battery pack according to claim 1, the battery case includes an upper member and a lower member; the upper member includes an upper central portion recessed from bottom to top, and an upper flange portion located on the periphery of the upper central portion, the lower member includes a lower central portion recessed from top to bottom and a lower flange portion located on the periphery of the lower central portion, the one or more battery cells are housed in a space surrounded by the upper central portion and the lower central portion, the space being closed by a seal member provided between the upper flange portion and the lower flange portion; The heat insulating material is fixed to the battery case through the sealing member. Vehicle battery pack.

4. 3. The vehicle battery pack according to claim 1, the structure defining the interior space includes an upper wall, a lower wall, and a side wall that surround the one or more battery cells; The heat insulating material is fixed to the battery case at the side wall. Vehicle battery pack.

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