A heat insulation pad and a battery pack

Abstract

This utility model belongs to the field of battery manufacturing technology and discloses a heat insulation pad and a battery pack. The heat insulation pad includes a first film layer, a second film layer, and a core. The core is used for heat insulation and is disposed between the first and second film layers. The circumferential edge of the first film layer is folded around the core to one side of the second film layer and connected to it, forming an encapsulation portion surrounding the core. The distance between the outer edge of the encapsulation portion and the adjacent edge of the core is H, and the thickness of the first film layer is D, where H = λD, 4 ≤ λ ≤ 2000. This utility model increases the heat insulation area of ​​the heat insulation pad, improving the heat insulation effect and the safety of the battery pack. This utility model allows for an increase in the area occupied by the core of the formed heat insulation pad, reducing the ineffective area for heat insulation. During use, it effectively increases the heat insulation area of ​​the battery, which is beneficial for achieving system thermal suppression.

Description

Technical Field

[0001] This utility model relates to the field of battery manufacturing technology, and in particular to heat insulation pads and battery packs. Background Technology

[0002] Thermal insulation pads are placed between batteries to prevent thermal runaway of a single battery from affecting other batteries, thereby avoiding a chain reaction of thermal runaway accidents and improving the overall safety of the battery pack.

[0003] like Figure 1 As shown, in the manufacturing process of existing heat insulation pads, an existing core 200 is sandwiched between two opposing existing film layers 100. The area of ​​the existing film layer 100 is larger than the area of ​​the existing core 200, so that the existing film layer 100 completely covers the existing core 200. The two existing film layers 100 are connected at the four edges of the existing core 200. Since the four edges of the existing core 200, which actually provide heat insulation, are the parts of the existing film layer 100 used for connection, they do not have heat insulation effect in this area. The existence of this area prevents the existing core 200 from maximizing the heat insulation area of ​​the heat insulation pad, resulting in insufficient effective heat insulation area between the batteries.

[0004] Currently, there is an urgent need for a heat insulation pad encapsulation structure that can increase the heat insulation area to improve the heat insulation effect and the safety of the battery pack. Utility Model Content

[0005] The purpose of this invention is to provide a heat insulation pad and a battery pack, which can increase the heat insulation area of ​​the heat insulation pad, improve the heat insulation effect and the safety of the battery pack.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] The first aspect relates to a heat insulation pad, the heat insulation pad comprising:

[0008] First membrane layer;

[0009] Second film layer;

[0010] A core, used for heat insulation, is disposed between the first film layer and the second film layer;

[0011] The circumferential edge of the first film layer is folded along the periphery of the core to one side of the second film layer and connected to the second film layer to form an encapsulation portion surrounding the core. The maximum distance between the outer edge of the encapsulation portion and the adjacent edge of the core is H, and the thickness of the first film layer is D, where H = λD, 4 ≤ λ ≤ 2000.

[0012] The second aspect relates to a battery pack, the battery pack comprising:

[0013] The box-shaped enclosure has a receiving cavity;

[0014] A battery module is disposed within the receiving cavity. The battery module includes a plurality of battery cells arranged in the same direction and two end plates that clamp the plurality of battery cells in the middle.

[0015] The above-mentioned heat insulation pad is disposed between two adjacent battery cells or between a battery cell and an end plate.

[0016] Beneficial effects:

[0017] In the first aspect of this invention, the circumferential edge of the first film layer is folded circumferentially and connected to the second film layer. After folding, the maximum distance between the outer edge of the encapsulation portion surrounding the core and the adjacent edge of the core is H, and H is limited to between 4D and 2000D. Compared to the prior art method of bonding two identical film layers together along their edges, the area occupied by the core of the formed heat insulation pad is increased, and the ineffective area for heat insulation is reduced. During use, the heat insulation area of ​​the battery is effectively increased, which is beneficial for achieving system thermal suppression. Furthermore, by continuously optimizing the above encapsulation process, the heat insulation area can be maximized.

[0018] In a second aspect of this invention, the battery pack based on this heat insulation pad can maximize the heat insulation effect and improve the safety of the battery pack. Attached Figure Description

[0019] Figure 1 A schematic diagram of a heat insulation pad in the prior art, in which two identical membrane layers are bonded together along their edges;

[0020] Figure 2 This is a schematic diagram of the composition of the heat insulation pad provided in this embodiment of the present invention before encapsulation;

[0021] Figure 3 This is a schematic diagram of the structure of the heat insulation pad provided in this embodiment of the utility model after encapsulation;

[0022] Figure 4 This is a cross-sectional schematic diagram of the heat insulation pad provided in this embodiment of the utility model.

[0023] In the picture:

[0024] 100. Existing membrane layer; 200. Existing core;

[0025] 1. First film layer; 11. First long side; 12. First short side; 2. Second film layer; 21. Second long side; 22. Second short side; 3. Core; 31. Third long side; 32. Third short side; 5. Heat insulation area; 6. Encapsulation part. Detailed Implementation

[0026] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, not the entire structure.

[0027] In the description of this utility model, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0028] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0029] In the description of this embodiment, the terms "upper," "lower," "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. In addition, the terms "first" and "second" are only used for distinction in description and have no special meaning.

[0030] It should be noted that the heat insulation pad can be placed between adjacent battery cells to prevent heat conduction between battery cells and prevent the thermal runaway of some battery cells from being transmitted to adjacent battery cells. Thus, when a battery cell experiences thermal runaway, it can suppress the spread of heat from that battery cell to other battery cells in the device, thereby improving safety.

[0031] The material of the heat insulation pad can be a composite material, such as epoxy resin, ceramics and glass wool, and any material with high heat insulation properties can be used.

[0032] Furthermore, the main body of the heat insulation pad is made of aerogel and a porous fiber substrate. The aerogel can be an inorganic porous aerogel material such as silica, and the porous fiber substrate includes at least one of pre-oxidized fiber felt, glass fiber felt, and ceramic fiber felt. Inorganic porous aerogel materials such as silica have extremely low thermal conductivity and good heat resistance.

[0033] Please see the appendix Figure 2 - Appendix Figure 4 The first aspect of this embodiment relates to a heat insulation pad, which includes a first film layer 1, a second film layer 2, and a core 3. The core 3 is used for heat insulation and is disposed between the first film layer 1 and the second film layer 2. The circumferential edge of the first film layer 1 is folded around the core 3 to one side of the second film layer 2 and connected to the second film layer 2 to form an encapsulation portion 6 surrounding the core 3. The maximum distance between the edge of the encapsulation portion 6 and the adjacent edge of the core 3 is H, and the thickness of the first film layer 1 is D, where H = λD, 4 ≤ λ ≤ 2000.

[0034] Specifically, the core 3 is used for heat insulation, and its interior is composed of heat insulation material, which can be pre-oxidized fiber aerogel, ceramic fiber aerogel, glass fiber aerogel, ceramic fiber mat, glass fiber mat, etc. The first film layer 1 and the second film layer 2 are used to encapsulate the core 3. The materials of the first film layer 1 and the second film layer 2 can be PET film, PI film, aluminum-plastic film, etc. Before encapsulation, the first film layer 1 can be placed on the lower side of the core 3, and the second film layer 2 can be placed on the upper side of the core 3 to form a covering. The first film layer 1 is larger in area than the core 3 and can completely cover the core 3. During encapsulation, the circumferential edge of the first film layer 1 is folded along the periphery of the core 3 to one side of the second film layer 2 and adhered to it, forming a complete covering.

[0035] In this embodiment, the first film layer 1 is folded around the periphery of the core 3 and connected to the second film layer 2. After folding, the maximum distance H between the outer edge of the encapsulation portion 6 surrounding the core 3 and the adjacent edge of the core 3 is ensured. The value of H ranges from 2 mm to 20 mm. ， The value of D ranges from 0.01mm to 0.5mm, and H is limited to between 4D and 2000D. H cannot be too large, as an excessively large H may not guarantee an effective heat insulation area, reducing the battery's heat insulation performance and safety; conversely, H cannot be too small, as this may increase the difficulty of the bonding process. Compared to the existing technology that uses two identical film layers bonded together along their edges (see Appendix...), this method... Figure 1This process allows for an increase in the area occupied by the core 3 of the formed heat insulation pad, reducing the ineffective area for heat insulation (i.e., the area where the encapsulation part 6 is located). During use, this effectively increases the heat insulation area of ​​the battery, which is beneficial for achieving system thermal suppression. It should be noted that by continuously optimizing the above encapsulation process, the heat insulation area can be maximized. With improvements in processing technology, the thickness of the core 3 can be further optimized to 0.05mm–0.08mm.

[0036] Please continue to refer to the appendix. Figure 2 Optionally, the first film layer 1 is formed by two opposing and longer first long sides 11 and two opposing and shorter first short sides 12; the core 3 is formed by two opposing and longer third long sides 31 and two opposing and shorter third short sides 32, wherein the distance between one of the first long sides 11 and one of the adjacent third long sides 31 is L1, and the value of L1 ranges from 2mm to 20mm.

[0037] Specifically, both the first film layer 1 and the core 3 are rectangular, with the first long side 11 and the third long side 31 being parallel to each other, and the first short side 12 and the third short side 32 being parallel to each other. Before encapsulation, the distance between one of the first long sides 11 and one of the adjacent third long sides 31 is L1. Since a portion of the first film layer 1 on L1 needs to be folded and connected to the second film layer 2, L1 cannot be too small. A small L1 will reduce the bonding area, thus affecting the bonding strength and making the encapsulation weak. Of course, L1 cannot be too large either, because an excessively large L1 will cause the area covered by the first film layer 1 on L1 after folding to increase, thereby reducing the area of ​​the core 3 that is solely covered by the second film layer 2. To a certain extent, this reduces the optimal contact area between the core 3 and the battery's heating surface, reducing the heat insulation effect. Therefore, in this embodiment, the value of L1 ranges from 2mm to 20mm.

[0038] Furthermore, the distance between the other first long side 11 and the adjacent third long side 31 is L2, and the value of L2 ranges from 2mm to 20mm.

[0039] Adaptively, before encapsulation, the distance between the other first long side 11 and the adjacent third long side 31 is L2. Therefore, L2 cannot be too small, as an excessively small L2 will reduce the bonding area, thus affecting the bonding strength and resulting in an unstable encapsulation. Conversely, L2 cannot be too large either, because an excessively large L2 will cause the first film layer 1 on L2 to fold over, increasing the coverage area of ​​the first film layer 1 superimposed on the second film layer 2. This reduces the effective area of ​​the core 3 covered solely by the second film layer 2, and to some extent, reduces the effective contact area between the core 3 and the battery's heating surface, thus lowering the heat insulation effect. Therefore, in this embodiment, the value of L2 ranges from 2mm to 20mm.

[0040] In this embodiment, L1 and L2 are not equal. Therefore, before encapsulation, it is entirely possible to avoid aligning the core 3 with the first film layer 1 in the width direction. That is, the core 3 does not need to be centered on the first film layer 1, avoiding the design and use of complex positioning fixtures. Of course, L1 and L2 should not differ too much; they should be adjusted mainly based on the bonding strength and the effective area of ​​coverage.

[0041] Optionally, the distance between one of the first short sides 12 and one of the adjacent third short sides 32 is L5, and the value of L5 ranges from 2mm to 20mm.

[0042] In this embodiment, since a portion of the first film layer 1 on L5 needs to be folded to connect with the second film layer 2, L5 cannot be too small. An excessively small L5 will reduce the bonding area, thus affecting the bonding strength and resulting in a weak seal. Conversely, L5 cannot be too large either, because an excessively large L5 will increase the coverage area of ​​the first film layer 1 superimposed on the second film layer 2 after folding, thereby reducing the area of ​​the core 3 solely covered by the second film layer 2. To a certain extent, this reduces the optimal contact area between the core 3 and the battery's heating surface, lowering the heat insulation effect. Therefore, in this embodiment, the value of L5 ranges from 2mm to 20mm.

[0043] Furthermore, the distance between the other first short side 12 and the adjacent third short side 32 is L6, and the value of L6 ranges from 2mm to 20mm.

[0044] Adaptively, before encapsulation, the distance between the other first short side 12 and the adjacent third short side 32 is L6. Therefore, L6 cannot be too small, as an excessively small L6 will reduce the bonding area, thus affecting the bonding strength and resulting in an unstable encapsulation. Conversely, L6 cannot be too large either, because an excessively large L6 will cause the first film layer 1 to fold over, increasing the coverage area of ​​the first film layer 1 superimposed on the second film layer 2. This reduces the area of ​​the core 3 solely covered by the second film layer 2, and to some extent, reduces the optimal contact area between the core 3 and the battery's heating surface, thus lowering the heat insulation effect. Therefore, in this embodiment, the value of L6 ranges from 2mm to 20mm.

[0045] It should be noted that the first short side 12 is shorter than the first long side 11. Therefore, in order to ensure a better or similar bonding strength to that at the first long side 11, L5 and L6 can be appropriately greater than L1 and L2.

[0046] In this embodiment, L5 and L6 are not equal. Therefore, before encapsulation, it is entirely possible to avoid aligning the core 3 with the first film layer 1 in the length direction. That is, the core 3 does not need to be centered on the first film layer 1, avoiding the design and use of complex positioning fixtures. Of course, L5 and L6 should not differ too much; adjustments can be made mainly based on the bonding strength and the adaptability of the effective coverage area.

[0047] Optionally, the second membrane layer 2 is formed by two opposing and longer second long sides 21 and two opposing and shorter second short sides 22; the distance between one of the third long sides 31 and the adjacent second long side 21 is L3, where L3 ≤ 6 mm.

[0048] Specifically, the second membrane layer 2 is rectangular. L3 can be 0, meaning that the third long side 31 on one side is aligned with the second long side 21 on the other side. However, L3 cannot be too large. If L3 is too large, it means that the distance between the third long side 31 and the second long side 21 on one side is too far, requiring an appropriate increase in the size of the first membrane layer 1. This could even lead to the two sides of the first membrane layer 1 being butt-jointed or overlapping, affecting the uniformity of the overall heat insulation pad thickness and increasing the difficulty of bonding. Therefore, in this embodiment, L3 ≤ 6mm, and when the processing accuracy allows, L3 ≤ 2mm.

[0049] In this embodiment, the length of the second long side 21 is less than or equal to the length of the third long side 31, and the length of the second short side 22 is less than or equal to the length of the third short side 32. Therefore, the second film layer 2 covers most of the core 3, or the second film layer 2 is completely aligned and adhered to the core 3.

[0050] Furthermore, the distance between the other third long side 31 and the adjacent other second long side 21 is L4, where L4 ≤ 6 mm.

[0051] Correspondingly, L4 can also be 0, meaning the third long side 31 on the other side is aligned with the second long side 21 on the other side. However, L4 cannot be too large. If L4 is too large, it means the third long side 31 on the other side is too far from the second long side 21 on the other side, requiring an appropriate increase in the size of the first film layer 1. This could even lead to butt joints or overlaps on both sides of the first film layer 1, affecting the overall uniformity of the insulation pad's thickness and increasing the difficulty of bonding. Therefore, in this embodiment, L4 ≤ 6 mm, and when the processing accuracy allows, L4 ≤ 2 mm.

[0052] In this embodiment, L3 and L4 are not equal. Therefore, before encapsulation, it is entirely possible to avoid aligning the position of the second film layer 2 relative to the core 3 in the width direction. That is, the second film layer 2 does not need to be centered on the core 3, thus avoiding the design and use of complex positioning fixtures.

[0053] Optionally, the area of ​​the first membrane layer 1 is S1, the area of ​​the second membrane layer 2 is S2, and 0.3≤S2 / S1≤0.5.

[0054] In this embodiment, the area S1 of the first membrane layer 1 is larger than the area of ​​the core 3, and the area S2 of the second membrane layer 2 is approximately equal to the area of ​​the core 3. However, the area S1 of the first membrane layer 1 is not significantly different from the areas of the core 3 and the second membrane layer 2. By ensuring that 0.3 ≤ S2 / S1 ≤ 0.5, while maintaining stable membrane layer connection, it further ensures a larger effective area of ​​the core 3 covered solely by the second membrane layer 2, thus guaranteeing the heat insulation effect. Typically, the length of the second membrane layer 2 ranges from 80mm to 1200mm, and the width ranges from 40mm to 300mm. The length and width of the first membrane layer 1 can be appropriately selected based on the designed folding operation.

[0055] Optionally, the area difference between the first membrane layer 1 and the core 3 is S4, and the area of ​​the second membrane layer 2 is S2, where 0.2≤S4 / S2≤0.4.

[0056] In this embodiment, the area difference between the first film layer 1 and the core 3 is S4. S4 refers to the portion of the first film layer 1 that is larger than the core 3, which is mainly used for bonding with the second film layer 2. The bonding area is approximately equal to S4. S4 cannot be too large relative to S2; otherwise, the optimal contact area between the core 3 and the battery's heat-generating surface may be reduced due to an excessively large stacked portion of the second film layer 2 and the first film layer 1, thus lowering the heat insulation effect. Based on this embodiment, the ratio is limited to 0.2 ≤ S4 / S2 ≤ 0.4, which ensures stable connection of the film layers while further guaranteeing the heat insulation effect. By optimizing the bonding process, S4 can be further reduced to ensure that the core 3 can achieve the optimal heat insulation effect. Typically, the length of the core 3 ranges from 120mm to 1200mm, and the width ranges from 80mm to 300mm.

[0057] Optionally, the heat insulation pad includes a heat insulation area 5 with a minimum thickness, the area of ​​the heat insulation area 5 is S5, the area of ​​the core 3 is S3, and S5 / S3≥0.8.

[0058] By optimizing the bonding process, the area S5 of the heat insulation zone 5 can be maximized to ensure that the heat insulation pad performs optimally. In this embodiment, by ensuring that S5 / S3 ≥ 0.8, S5 is limited to meet the heat insulation requirements of the battery.

[0059] The second aspect of this embodiment also relates to a battery pack.

[0060] It should be noted that the battery pack includes a battery management system (BMS), a thermal management system, an electrical connection system (high-voltage / low-voltage connectors, wiring harnesses, etc.), structural components (shell, brackets, etc.), and protective components, etc., which are combined into a battery pack by connecting multiple battery cells in series and / or in parallel, forming a complete functional unit that can directly output electrical energy.

[0061] Battery packs, as a type of rechargeable battery, are the power source for new energy vehicles.

[0062] A battery pack typically includes cell modules, a battery management system (BMS) control module, and a housing that contains the cell modules and the BMS control module.

[0063] The battery pack includes a housing and multiple individual batteries housed within the housing. The housing is divided into upper and lower parts, which are sealed together.

[0064] The battery pack includes at least two battery cells, a BMS control assembly, and a casing.

[0065] A battery pack typically consists of a battery box and battery modules. The battery box includes a lower casing and a top cover.

[0066] A battery pack typically includes a housing, individual battery cells, and a separator. Both the individual battery cells and the separator are located inside the housing. The separator is located on the side of the individual battery cell away from the bottom wall of the housing, separating the individual battery cell from other components located above it, thus providing isolation.

[0067] In this embodiment, the battery pack includes a housing, a battery module, and a heat insulation pad. The housing has a receiving cavity; the battery module is disposed within the receiving cavity and includes multiple battery cells arranged in the same direction, and two end plates clamping the multiple battery cells in the middle; the heat insulation pad is disposed between two adjacent battery cells or between a battery cell and an end plate.

[0068] Specifically, the casing is typically rectangular in shape, with a cavity inside to contain and house the battery module. Thermal insulation pads are sandwiched between adjacent cells within the battery module or between a cell and the end plate to prevent a cascading thermal runaway accident caused by a single cell.

[0069] Battery packs based on this heat insulation pad can maximize heat insulation performance and improve battery pack safety.

[0070] Obviously, the above embodiments of this utility model are merely examples for clearly illustrating the present utility model, and are not intended to limit the implementation of the present utility model. Those skilled in the art can make various obvious changes, readjustments, and substitutions without departing from the protection scope of this utility model. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the protection scope of the claims of this utility model.

Claims

1. A thermal insulation mat, characterized in that, include: First membrane layer (1); Second film layer (2); A core (3) is used for heat insulation, and the core (3) is disposed between the first film layer (1) and the second film layer (2); The circumferential edge of the first film layer (1) is folded around the core (3) to one side of the second film layer (2) and connected to the second film layer (2) to form an encapsulation part (6) surrounding the core (3). The maximum distance between the outer edge of the encapsulation part (6) and the adjacent edge of the core (3) is H. The thickness of the first film layer (1) is D, where H = λD and 4 ≤ λ ≤ 2000.

2. The insulating mat according to claim 1, characterized in that The value of H ranges from 2mm to 20mm; the value of D ranges from 0.01mm to 0.5mm.

3. The insulating mat according to claim 2, characterized in that The value of D ranges from 0.05 mm to 0.08 mm.

4. The insulating mat of claim 1, wherein, The first film layer (1) includes two opposing and longer first long sides (11) and two opposing and shorter first short sides (12); the core (3) includes two opposing and longer third long sides (31) and two opposing and shorter third short sides (32), wherein the distance between one of the first long sides (11) and one of the adjacent third long sides (31) is L1, and the value of L1 ranges from 2mm to 20mm.

5. The insulating mat of claim 4, wherein, The distance between the other first long side (11) and the other adjacent third long side (31) is L2, and the value of L2 ranges from 2mm to 20mm.

6. The heat insulation pad according to claim 5, characterized in that, L1 and L2 are not equal.

7. The heat insulation pad according to claim 4, characterized in that, The distance between one of the first short sides (12) and one of the adjacent third short sides (32) is L5, and the value of L5 ranges from 2mm to 20mm.

8. The heat insulation pad according to claim 7, characterized in that, The distance between the other first short side (12) and the other adjacent third short side (32) is L6, and the value of L6 ranges from 2mm to 20mm.

9. The heat insulation pad according to claim 8, characterized in that, L5 and L6 are not equal.

10. The heat insulation pad according to claim 1, characterized in that, The area of ​​the core (3) is S3, and the area of ​​the second film layer (2) is S2, where S3 ≥ S2.

11. The heat insulation pad according to claim 10, characterized in that, The second film layer (2) includes two opposing and longer second long sides (21) and two opposing and shorter second short sides (22); the core (3) includes two opposing and longer third long sides (31) and two opposing and shorter third short sides (32); The length of the second long side (21) is less than or equal to the length of the third long side (31), and the length of the second short side (22) is less than or equal to the length of the third short side (32).

12. The heat insulation pad according to claim 1, characterized in that, The second film layer (2) includes two opposing and longer second long sides (21) and two opposing and shorter second short sides (22); the core (3) includes two opposing and longer third long sides (31) and two opposing and shorter third short sides (32), wherein the distance between one of the third long sides (31) and one of the adjacent second long sides (21) is L3, and L3≤6mm.

13. The heat insulation pad according to claim 12, characterized in that, L3≤2mm.

14. The heat insulation pad according to claim 12, characterized in that, The distance between the other third long side (31) and the adjacent second long side (21) is L4, where L4 ≤ 6 mm.

15. The heat insulation pad according to claim 14, characterized in that, L4≤2mm.

16. The heat insulation pad according to claim 14, characterized in that, L3 and L4 are not equal.

17. The heat insulation pad according to claim 1, characterized in that, The area of ​​the first film layer (1) is S1, the area of ​​the second film layer (2) is S2, and 0.3≤S2 / S1≤0.

5.

18. The heat insulation pad according to claim 1, characterized in that, The area difference between the first film layer (1) and the core (3) is S4, and the area of ​​the second film layer (2) is S2, wherein 0.2≤S4 / S2≤0.

4.

19. The heat insulation pad according to any one of claims 1-18, characterized in that, The heat insulation pad includes a heat insulation area (5) with a minimum thickness, the area of ​​the heat insulation area (5) is S5, the area of ​​the core (3) is S3, and the ratio of S5 / S3 is ≥ 0.

8.

20. A battery pack, characterized in that, include: The box-shaped enclosure has a receiving cavity; A battery module is disposed within the receiving cavity. The battery module includes a plurality of battery cells arranged in the same direction and two end plates that clamp the plurality of battery cells in the middle. The heat insulation pad according to any one of claims 1 to 19, wherein the heat insulation pad is disposed between two adjacent battery cells or between the battery cell and the end plate.

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