Heat insulating material and battery module including the same

Abstract

To reduce the reaction force that an insulating material exerts on a battery cell when the battery cell expands.SOLUTION: A battery module 10 includes battery cells 12 arranged with a pair of wide surfaces 12a facing each other, and a heat insulating material 30 disposed between adjacent battery cells 12 which is a pair. The heat insulating material 30 includes a heat insulating sheet 40 and a buffer sheet 50 attached to the heat insulating sheet 40. The buffer sheet 50 is made of a material that is more susceptible to compressive deformation than the heat insulating sheet 40. The heat insulating sheet 40 has a recess 42 on the surface to which the buffer sheet 50 is attached.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a heat insulating material and a battery module including the same. [Background technology]

[0002] JP 2021-140968 A discloses a battery insulating material that includes an insulating portion disposed opposite the surface of the battery and a buffer portion that is more susceptible to compressive deformation than the insulating portion, with at least a portion of the buffer portion disposed closer to the battery surface than the insulating portion. According to JP 2021-140968 A, even if the battery expands, for example, the battery insulating material appropriately compresses and deforms in response to the expansion of the battery, so that the expansion of the battery is not excessively suppressed. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2021-140968 Summary of the Invention [Problem to be solved by the invention]

[0004] However, as the expansion of the battery increases, the force with which the battery compresses the insulation increases. When the force with which the battery compresses the insulation increases, strain accumulates in the buffer section, and the reaction force with which the insulation tries to push back against the battery increases. When the reaction force increases, the restraining members required to deal with this increase become larger, which poses a problem of the battery module becoming larger and heavier. [Means for solving the problem]

[0005] The thermal insulation material disclosed herein is an insulation material disposed between a pair of adjacent battery cells of a battery module. The insulation material includes an insulating sheet and a buffer sheet attached to the insulating sheet. The buffer sheet is made of a material that is more easily compressed and deformed than the insulating sheet. The insulating sheet has a recess on the surface to which the buffer sheet is attached. With this insulation material, when the battery cells expand and the insulation material is compressed and deformed, the buffer sheet deforms so that part of the buffer sheet enters the recess, thereby releasing the strain accumulated in the buffer sheet. This alleviates the reaction force that the insulation material exerts on the battery. As a result, the strength of the restraining member can be reduced, and the mass and size of the battery module can be reduced. [Brief explanation of the drawings]

[0006] [Figure 1] FIG. 1 is a plan view schematically showing a battery module according to one embodiment. [Figure 2] FIG. 2 is a cross-sectional view taken along line AA in FIG. [Figure 3] FIG. 3 is a front view schematically showing the heat insulating sheet. [Figure 4] FIG. 4 is a front view schematically showing the buffer sheet. [Figure 5] FIG. 5 is a front view schematically showing the heat insulating material as viewed from the buffer sheet side. [Figure 6] FIG. 6 is a cross-sectional view taken along the line BB in FIG. [Figure 7] FIG. 7 is a cross-sectional view that schematically shows the heat insulating material when the battery cell is expanded. [Figure 8] FIG. 8 is a front view schematically showing a heat insulating material according to another embodiment. [Figure 9] FIG. 9 is a front view schematically showing a heat insulating material according to another embodiment. [Figure 10] FIG. 10 is a front view schematically showing a heat insulating material according to another embodiment. [Figure 11] FIG. 11 is a front view schematically showing a heat insulating material according to another embodiment. [Figure 12]FIG. 12 is a cross-sectional view taken along line DD in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0007] An embodiment of the technology disclosed herein will be described below with reference to the drawings. The embodiments described herein are, of course, not intended to limit the present invention. The drawings are schematic and do not necessarily reflect the actual product. Components and parts performing the same function are appropriately designated by the same reference numerals, and redundant descriptions will be omitted where appropriate. The notation "A to B" indicating a numerical range means "A or greater and B or less" unless otherwise specified. In the following description, the symbols X, Y, and Z in the drawings represent the thickness direction, width direction perpendicular to the thickness direction, and height direction perpendicular to the thickness and width directions, respectively, of the battery module 10. However, these directions are merely provided for convenience of explanation and do not limit the installation form of the battery module 10.

[0008] Fig. 1 is a plan view schematically showing a battery module 10. Fig. 2 is a cross-sectional view taken along line AA in Fig. 1. As shown in Fig. 1, the battery module 10 includes a plurality of battery cells 12, a restraining member 20, and a heat insulating material 30. Note that Fig. 1 shows an arrangement of six battery cells 12, but the number of battery cells 12 included in the battery module 10 is not limited to this.

[0009] The battery cell 12 is a battery cell having a pair of wide surfaces 12a. In this embodiment, the battery cell 12 is a rectangular battery cell having a rectangular case having a substantially rectangular parallelepiped shape. The battery cell 12 may be a laminated battery cell covered with a laminate film. The plurality of battery cells 12 are arranged with their wide surfaces 12a facing each other. The plurality of battery cells 12 are arranged in the X direction.

[0010] Here, "battery cell" refers to the smallest unit of an electricity storage device. "Electricity storage device" refers to a device that can be charged and discharged. Energy storage devices include batteries generally referred to as lithium ion batteries and lithium secondary batteries, as well as batteries such as lithium polymer batteries. A secondary battery generally refers to a battery that can be repeatedly charged and discharged through the movement of charge carriers between the positive and negative electrodes. An electricity storage device may use an electrolyte or a solid electrolyte. For example, a secondary battery may be a secondary battery that uses a so-called liquid electrolyte, or a so-called all-solid-state battery that uses a solid electrolyte. Furthermore, a "battery module" is an electricity storage device that incorporates multiple battery cells.

[0011] The restraining member 20 restrains the multiple battery cells 12 arranged with their wide surfaces 12a facing each other and the heat insulating material 30 arranged between the battery cells 12. The restraining member 20 is configured to apply a required restraining pressure to the multiple battery cells 12 and the heat insulating material 30. The restraining member 20 includes a pair of end plates 21, a pair of side plates 22, and multiple screws. Note that the screws are not shown in FIG. 1 . The end plates 21 are arranged at both ends of the multiple battery cells 12 in the X direction. The end plates 21 sandwich the multiple battery cells 12 in the X direction. The side plates 22 are arranged at both ends of the battery cells 12 in the Y direction. The side plates 22 are fastened to the end plates 21 with multiple screws so that a required restraining pressure is applied to the battery cells 12 and the heat insulating material 30. The materials of the end plates 21 and the side plates 22 are not particularly limited. For example, the end plates 21 and the side plates 22 may be made of an aluminum alloy. The configuration of the restraint member 20 is not limited to this, and any configuration that is used in a battery module can be used.

[0012] As shown in Figures 1 and 2, the heat insulating material 30 is disposed between a pair of adjacent battery cells 12. The heat insulating material 30 is a member that suppresses heat conduction between the pair of adjacent battery cells 12. For example, when one of the pair of adjacent battery cells 12 generates abnormal heat, the heat insulating material 30 suppresses heat conduction to the other battery cell 12. In this embodiment, as shown in Figure 1, heat insulating materials 30 are also disposed between the battery cells 12 at both ends in the X direction and the end plates 21, but this is not necessary. The heat insulating material 30 includes a heat insulating sheet 40 and a buffer sheet 50.

[0013] Fig. 3 is a front view schematically showing the heat insulating sheet 40. Fig. 4 is a front view schematically showing the buffer sheet 50. Fig. 5 is a front view schematically showing the heat insulating material 30 in which the heat insulating sheet 40 and the buffer sheet 50 are bonded together. Fig. 5 shows the heat insulating material 30 as seen from the buffer sheet 50 side. Fig. 6 is a cross-sectional view taken along line BB of Fig. 5.

[0014] The heat insulating sheet 40 is a component that imparts the desired heat insulating performance to the heat insulating material 30. The heat insulating sheet 40 is preferably made of a material with low thermal conductivity. For example, the material of the heat insulating sheet 40 is preferably inorganic fiber such as glass wool. The material of the heat insulating sheet 40 may be a material containing inorganic fiber and an organic binder, a material containing inorganic fiber and inorganic powder, or a material containing inorganic filler and an organic binder. The material of the heat insulating sheet 40 may also be aerogel, expanded silicon, or the like.

[0015] In the embodiment shown in Fig. 3, the heat insulating sheet 40 is formed in a rectangular parallelepiped shape. In this embodiment, as shown in Fig. 1, the width of the heat insulating sheet 40 is approximately equal to the width of the battery cell 12. In this embodiment, as shown in Fig. 2, the height of the heat insulating sheet 40 is approximately equal to the height of the battery cell 12. In other words, the heat insulating sheet 40 is formed to be approximately the same size as the wide surface 12a of the battery cell 12. Here, "width" refers to the length in the Y direction, and "height" refers to the length in the Z direction.

[0016] The thickness of the heat insulating sheet 40 is not particularly limited. Here, "thickness" refers to the length in the X direction. If the thickness of the heat insulating sheet 40 is increased, the battery module 10 will become larger, but the heat insulating performance of the heat insulating material 30 will improve. If the thickness of the heat insulating sheet 40 is decreased, the heat insulating performance of the heat insulating material 30 will decrease, but the battery module 10 can be made smaller. The thickness of the heat insulating sheet 40 can be changed as appropriate, taking these factors into consideration. For example, the thickness of the heat insulating sheet 40 is preferably 1 mm to 10 mm, and more preferably 1 mm to 4 mm.

[0017] As shown in FIG. 3 , the heat insulating sheet 40 has recesses 42 on the surface 40a to which the buffer sheet 50 is attached. In this embodiment, the recesses 42 are formed as through holes that penetrate the heat insulating sheet 40 in the X direction. The shape of the through holes is not particularly limited, but in this embodiment, they are formed in an elliptical shape. The minor axis of the recesses 42 is preferably 20 mm or less, and more preferably 15 mm or less. The shape of the recesses 42 may be circular or rectangular. There is no particular limit to the number of recesses 42. In this embodiment, the heat insulating sheet 40 has six recesses 42. The arrangement of the recesses 42 is not particularly limited, but it is preferable that the recesses 42 are evenly arranged on the surface 40a to which the buffer sheet 50 is attached.

[0018] The heat insulating sheet 40 has an air passage 44 connecting the recess 42 and the peripheral edge of the heat insulating sheet 40. This allows air to flow between the recess 42 and the peripheral edge of the heat insulating sheet 40 through the air passage 44. In this embodiment, the air passage 44 is a through-hole formed inside the heat insulating sheet 40. The air passage 44 extends from the recess 42 in the Y direction or the Z direction. The cross-sectional shape of the air passage 44 is not particularly limited, but in this embodiment it is formed in a circular shape. The diameter of the air passage 44 is not particularly limited. For example, the diameter of the air passage 44 may be approximately half the thickness of the heat insulating sheet 40.

[0019] In this embodiment, the heat insulating sheet 40 has ventilation channels 46 that connect the recesses 42 together. This makes it easier for air to flow through the heat insulating sheet 40 compared to when the heat insulating sheet 40 does not have the ventilation channels 46. In this embodiment, the ventilation channels 46 are circular through-holes formed inside the heat insulating sheet 40, similar to the ventilation channels 44. The diameter of the ventilation channels 46 is not particularly limited, and may be the same as the diameter of the ventilation channels 44. It is noted that the heat insulating sheet 40 does not necessarily have to have the ventilation channels 46.

[0020] As shown in FIG. 3, the heat insulating sheet 40 has positioning holes 48. The positioning holes 48 are formed on the surface 40a to which the buffer sheet 50 is attached. The arrangement of the positioning holes 48 is not particularly limited. In this embodiment, the positioning holes 48 are provided at the four corners of the heat insulating sheet 40. In this embodiment, the positioning holes 48 are circular through holes. Note that the positioning holes 48 may be blind holes instead of through holes.

[0021] The buffer sheet 50 is made of a material that is more easily compressed and deformed than the heat insulating sheet 40. Various rubber materials can be suitably used as the material for the buffer sheet 50. The buffer sheet 50 is preferably made of silicone rubber, fluororubber, urethane rubber, natural rubber, styrene butadiene rubber, butyl rubber, ethylene propylene rubber, butadiene rubber, isoprene rubber, norbornene rubber, or the like. The buffer sheet 50 is particularly preferably made of silicone rubber or fluororubber.

[0022] The buffer sheet 50 is attached to the heat insulating sheet 40. For example, the buffer sheet 50 is attached to the heat insulating sheet 40 with an adhesive or double-sided tape. The buffer sheet 50 is a member provided to reduce the reaction force that the heat insulating material 30 exerts on the battery cells 12 when the battery cells 12 expand.

[0023] In the embodiment shown in FIG. 4, the buffer sheet 50 is formed in a rectangular parallelepiped shape. The width of the buffer sheet 50 is not particularly limited. In this embodiment, as shown in FIG. 1, the width is approximately equal to the width of the buffer sheet 50. The width of the buffer sheet 50 may be smaller than the width of the heat insulating sheet 40. The height of the buffer sheet 50 is also not particularly limited. In this embodiment, as shown in FIG. 2, the height of the buffer sheet 50 is approximately equal to the height of the heat insulating sheet 40. The height of the buffer sheet 50 may be smaller than the height of the heat insulating sheet 40. The thickness of the buffer sheet 50 is also not particularly limited. The thickness of the buffer sheet 50 is preferably 1 mm to 10 mm. The thickness of the buffer sheet 50 is particularly preferably 1 mm to 4 mm. The thickness of the buffer sheet 50 may be larger or smaller than the thickness of the heat insulating sheet 40. The thickness of the buffer sheet 50 may be equal to the thickness of the heat insulating sheet 40.

[0024] In the embodiment shown in FIG. 4 , the buffer sheet 50 has protrusions 52 on its surface 50b opposite the surface 50a to which the heat insulating sheet 40 is attached. The protrusions 52 are pressed by the battery cells 12 when the battery cells 12 expand. The shape of the protrusions 52 is not particularly limited, but in this embodiment, they are cylindrical. However, the protrusions 52 may also be elliptical cylindrical or rectangular parallelepiped. The diameter of the protrusions 52 is not particularly limited. In this embodiment, as shown in FIG. 5 , the diameter is shorter than the minor axis of the recesses 42. In this embodiment, the protrusions 52 are arranged so that a portion of each protrusion 52 overlaps with the recesses 42 when the heat insulating material 30 is viewed from the X direction. The number and arrangement of the protrusions 52 are not particularly limited. The protrusions 52 are preferably evenly arranged, similar to the recesses 42. In this embodiment, 24 protrusions 52 are evenly arranged on the buffer sheet 50. In this embodiment, the protrusions 52 are arranged in a row of four in the Z direction and in six rows in the Y direction. When the battery cells 12 expand and compress the thermal insulation material 30, part of the buffer sheet 50 deforms and enters the recess 42, and at the same time, the protrusion 52 tends to collapse toward the recess 42. To reduce the resulting misalignment between the buffer sheet 50 and the thermal insulation sheet 40, it is preferable that the protrusion 52 be positioned symmetrically with respect to the recess 42 when viewed from the X direction.

[0025] In the embodiment shown in FIG. 6 , the buffer sheet 50 has positioning protrusions 54 that protrude from the surface 40a to which the heat insulating sheet 40 is attached. The positioning protrusions 54 are inserted into the positioning holes 48. The positioning protrusions 54 are arranged so as to overlap the positioning holes 48 when viewed from the X direction. In this embodiment, as shown in FIG. 4 , the positioning protrusions 54 are provided at the four corners of the buffer sheet 50. The shape of the positioning protrusions 54 is not particularly limited. In this embodiment, as shown in FIG. 6 , the positioning protrusions 54 are formed in a truncated cone shape. The diameter of the positioning protrusions 54 decreases toward the tip. The shape of the positioning protrusions 54 may also be cylindrical, for example. It is preferable that the diameter of the bottom surface of the positioning protrusions 54 is approximately the same as the diameter of the positioning holes 48. The small tip of the positioning protrusions 54 makes it easy to insert them into the positioning holes 48 provided in the heat insulating sheet 40. Furthermore, since the diameter of the bottom surface of the positioning protrusion 54 is equal to the diameter of the positioning hole 48 of the heat insulating sheet 40, the heat insulating sheet 40 and the buffer sheet 50 can be overlapped with high precision.

[0026] 7 is a cross-sectional view that schematically shows the thermal insulation material 30 when the battery cell 12 is expanding. When the battery cell 12 expands, the protrusions 52 of the buffer sheet 50 are pressed by the battery cell 12, compressing the buffer sheet 50. At this time, the buffer sheet 50 deforms so as to enter the recesses 42 of the thermal insulation sheet 40. Furthermore, in this embodiment, the thermal insulation sheet 40 has ventilation channels 44, 46. Therefore, when the buffer sheet 50 enters the recesses 42, some of the air that has accumulated in the recesses 42 is pushed out to the peripheral edge of the thermal insulation sheet 40 through the ventilation channels 44, 46.

[0027] According to this embodiment, the heat insulating material 30 is disposed between a pair of adjacent battery cells 12 of the battery module 10. The heat insulating material 30 includes a heat insulating sheet 40 and a buffer sheet 50 attached to the heat insulating sheet 40. The buffer sheet 50 is made of a material that is more easily compressed and deformed than the heat insulating sheet 40. The heat insulating sheet 40 has a recess 42 on the surface 40a to which the buffer sheet 50 is attached. As a result, when the battery cells 12 expand and compress the heat insulating material 30, the buffer sheet 50 deforms to fit into the recess 42. This reduces the reaction force that the heat insulating material 30 exerts to push back against the battery cells 12.

[0028] According to this embodiment, the recesses 42 are formed as through-holes that penetrate the heat insulating sheet 40. Therefore, the recesses 42 can be formed in the heat insulating sheet 40 by simple machining. Furthermore, because the recesses 42 are through-holes, a sufficient volume for the buffer sheet 50 to fit into can be ensured compared to when the recesses 42 are blind holes. In particular, when the thickness of the heat insulating sheet 40 is thinner than the buffer sheet 50, the volume of the recesses 42 is relatively small compared to the volume of the buffer sheet 50, so it is preferable to form the recesses 42 as through-holes.

[0029] However, if the heat insulating sheet 40 does not have the ventilation channels 44, 46, when the buffer sheet 50 tries to deform to fit into the recess 42, the air in the recess 42 has no way to escape. As a result, the air in the recess 42 is compressed by the buffer sheet 50. Furthermore, it may become difficult for the buffer sheet 50 to deform to fit into the recess 42.

[0030] According to this embodiment, the heat insulating sheet 40 has ventilation channels 44, 46 that connect the recesses 42 and the peripheral edge of the heat insulating sheet 40. When the buffer sheet 50 enters the recesses 42, the air remaining in the recesses 42 can flow through the ventilation channels 44, 46 to the peripheral edge of the heat insulating sheet 40. This makes it easier for the buffer sheet 50 to deform and enter the recesses 42 compared to when the heat insulating sheet 40 does not have the ventilation channels 44, 46. Furthermore, the air remaining in the recesses 42 flows to the peripheral edge of the heat insulating sheet 40, making it easier to dissipate heat generated by the battery cells 12.

[0031] According to this embodiment, the buffer sheet 50 has a protrusion 52 on its surface 50b opposite the surface 50a to which the heat insulating sheet 40 is attached. This creates a gap 56 between the battery cells 12 and the portion of the buffer sheet 50 other than the protrusion 52. Therefore, when the battery cells 12 expand and compress the buffer sheet 50, the buffer sheet 50 can deform toward the gap 56. The heat insulating material 30 is likely to be appropriately compressed and deformed in response to the expansion of the battery cells 12.

[0032] According to this embodiment, the protrusions 52 are provided so as to partially overlap the recesses 42 when viewed from the X direction. This allows the buffer sheet 50 to easily deform so as to fit into the recesses 42 of the heat insulating sheet 40.

[0033] According to this embodiment, the buffer sheet 50 has a positioning protrusion 54 that protrudes from the surface 50a to which the heat insulating sheet 40 is attached. The heat insulating sheet 40 has a positioning hole 48 into which the positioning protrusion 54 is inserted. This allows the buffer sheet 50 to be positioned relative to the heat insulating sheet 40. When the heat insulating sheet 40 and the buffer sheet 50 are attached to each other, the heat insulating sheet 40 can be prevented from moving relative to the buffer sheet 50. The heat insulating sheet 40 and the buffer sheet 50 can be easily attached to each other so that part of the protrusion 52 overlaps with the recess 42 when viewed from the X direction.

[0034] Although one embodiment of the technology proposed here has been described above, the above embodiment is merely an example and the technology can be implemented in other modes.

[0035] 8 to 10 are front views schematically showing the heat insulating material 30 according to other embodiments. In Fig. 8 to Fig. 10, the heat insulating material 30 is shown as seen from the buffer sheet 50 side. As shown in Fig. 8, the protruding portions 52 may be formed in a lattice pattern. The recessed portions 42 may be arranged so that at least a portion of each recessed portion 42 overlaps with the protruding portions 52. The recessed portions 42 may be formed as circular through-holes.

[0036] 9, the protrusion 52 may be formed in an elliptical cylindrical shape, and the recess 42 may be formed as a circular through-hole. The minor axis of the protrusion 52 may be larger than the diameter of the recess 42. One protrusion 52 may be provided so as to overlap multiple recesses 42.

[0037] As shown in Fig. 10, the recess 42 may be formed as a rectangular through-hole. When the recess 42 is formed as a rectangular through-hole, the length of the short side of the recess 42 is preferably 20 mm or less, and more preferably 15 mm or less.

[0038] FIG. 11 is a schematic front view of another embodiment of the thermal insulation material 30. FIG. 11 illustrates the thermal insulation material 30 as viewed from the buffer sheet 50 side. FIG. 12 is a DD cross-sectional view of the thermal insulation material 30 shown in FIG. 11. As shown in FIGS. 11 and 12, the recesses 42 may not be through-holes but may be grooves formed on the surface 40a of the thermal insulation sheet 40 to which the buffer sheet 50 is attached. By using grooves instead of through-holes as the recesses 42, the thermal insulation performance of the thermal insulation material 30 is less likely to deteriorate compared to when the recesses 42 are through-holes. As shown in FIG. 11, the recesses 42 may be formed in a lattice pattern and extend to the peripheral edge of the thermal insulation sheet 40. If the recesses 42 are formed to extend to the peripheral edge of the thermal insulation sheet 40 in this manner, when the buffer sheet 50 deforms to enter the recesses 42, the air trapped in the recesses 42 can flow to the peripheral edge of the thermal insulation sheet 40. That is, in the heat insulating material 30 shown in FIG. 11, the recess 42 also functions as the ventilation flow paths 44, 46 in the above-described embodiment.

[0039] Further, the recess 42 may be a groove formed in a circular, elliptical, rectangular, etc. For example, in the embodiment shown in Fig. 5, 9, or 10, the recess 42 may be a blind hole instead of a through hole.

[0040] In the above embodiment, the buffer sheet 50 is attached to one side of the heat insulating sheet 40, but the buffer sheet 50 may be attached to both sides of the heat insulating sheet 40. That is, the buffer sheet 50 may be disposed between two heat insulating sheets 40. In this case, the recessed portion 42 may be provided on both sides of the two heat insulating sheets 40, or on only one of them. In this case, the protruding portion 52 may be provided on both sides of the buffer sheet 50, or on only one of them.

[0041] Alternatively, buffer sheets 50 may be attached to both sides of the heat insulating sheet 40. That is, the heat insulating sheet 40 may be disposed between two buffer sheets 50. In this case, the protrusions 52 may be provided on both of the two buffer sheets 50, or on only one of them. When the recesses 42 are grooves, the recesses 42 may be provided on both sides of the heat insulating sheet 40, or on only one of them.

[0042] The technology disclosed herein has been described in various ways. Unless otherwise specified, the embodiments and the like described herein do not limit the present invention. Furthermore, the technology disclosed herein can be modified in various ways, and as long as no particular problems arise, each component and each process described herein can be omitted or combined as appropriate. Furthermore, this specification includes the disclosures described in the following sections.

[0043] Section 1: A heat insulating material disposed between a pair of adjacent battery cells of a battery module, A heat insulating sheet, A buffer sheet attached to the heat insulating sheet; Equipped with The buffer sheet is made of a material that is more easily compressed and deformed than the heat insulating sheet, The heat insulating sheet has a recess on the surface to which the buffer sheet is attached. Insulation material.

[0044] Section 2: Item 2. The heat insulating material according to item 1, wherein the recess is formed by a through hole penetrating the heat insulating sheet.

[0045] Section 3: Item 2. The heat insulating material according to item 1, wherein the recess is a groove formed on the surface to which the buffer sheet is attached.

[0046] Section 4: Item 4. The heat insulating material according to any one of items 1 to 3, wherein the heat insulating sheet has an air flow path connecting the recess and a peripheral portion of the heat insulating sheet.

[0047] Section 5: Item 5. The heat insulating material according to any one of items 1 to 4, wherein the buffer sheet has a protruding portion on the surface opposite to the side attached to the heat insulating sheet.

[0048] Item 6: Item 6. The heat insulating material according to item 5, wherein a portion of the protrusion is provided so as to overlap the recess when viewed from the front.

[0049] Section 7: The buffer sheet has a positioning protrusion that protrudes from a surface that is bonded to the heat insulating sheet, Item 7. The heat insulating material according to any one of items 1 to 6, wherein the heat insulating sheet has a positioning hole into which the positioning protrusion is inserted.

[0050] Section 8: A plurality of battery cells arranged with a pair of wide surfaces facing each other; A battery module in which the heat insulating material according to any one of items 1 to 7 is disposed between a pair of adjacent battery cells. [Explanation of symbols]

[0051] 10 Battery Module 12 battery cells 30 Insulation 40 Heat insulation sheet 42 recess 44 Ventilation channel 48 Positioning hole 50 buffer sheets 52 Protrusion 54 Positioning protrusion

Claims

1. A heat insulating material disposed between a pair of adjacent battery cells of a battery module, A heat insulating sheet, A buffer sheet attached to the heat insulating sheet; Equipped with The buffer sheet is made of a material that is more easily compressed and deformed than the heat insulating sheet, The heat insulating sheet has a recess on the surface to which the buffer sheet is attached. Insulation material.

2. The heat insulating material according to claim 1 , wherein the recess is formed by a through hole that penetrates the heat insulating sheet.

3. The heat insulating material according to claim 1 , wherein the recess is a groove formed in the surface to which the buffer sheet is attached.

4. The heat insulating material according to claim 1 , wherein the heat insulating sheet has an air passage that connects the recess and a peripheral edge of the heat insulating sheet.

5. The heat insulating material according to claim 1 , wherein the buffer sheet has a protruding portion protruding from a surface opposite to the surface attached to the heat insulating sheet.

6. The heat insulating material according to claim 5 , wherein a part of the protrusion is provided so as to overlap the recess when viewed from the front.

7. The buffer sheet has a positioning protrusion that protrudes from the surface attached to the heat insulating sheet. The heat insulating material according to claim 1 , wherein the heat insulating sheet has a positioning hole into which the positioning protrusion is inserted.

8. A plurality of battery cells arranged with a pair of wide surfaces facing each other; A battery module in which the heat insulating material according to any one of claims 1 to 7 is disposed between a pair of adjacent battery cells.

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