Heating film assembly for battery pack and battery pack

Abstract

The invention provides a heating film assembly for a battery pack and the battery pack, the heating film assembly for the battery pack comprises an adhesive layer, a first insulating layer, a second insulating layer and a heating layer, the adhesive layer is used for bonding with a cold plate of the battery pack; the first insulating layer is connected with one side, deviating from the cold plate, of the adhesive layer; the second insulating layer is used for being bonded with a battery cell module of the battery pack through heat-conducting glue; the heating layer is clamped between the first insulating layer and the second insulating layer; wherein the thickness of the first insulating layer is not less than 0.2 mm. According to the invention, the problem that the heating film in the prior art is unreasonable in structure and cannot ensure effective heating of the battery cell is solved.

Description

Technical Field

[0001] This invention relates to the field of battery thermal management technology, and more specifically, to a heating film assembly for a battery pack and a battery pack. Background Technology

[0002] In existing technologies, electric vehicle battery systems often use coolant to directly cool the battery cells. However, in low-temperature environments, in order to maintain the normal operating temperature of the battery, a heating film is usually integrated inside the battery pack to provide the necessary heat.

[0003] However, existing heating films are placed on the side or top of the battery cell to achieve heating. But this method can lead to the heating film burning out when the battery cell expands or the top is uneven, and it also adds extra metal plates and complex structures, increasing costs. In addition, the existing heating film has an unreasonable structural design and cannot ensure effective heating of the battery cell. Summary of the Invention

[0004] The main objective of this invention is to provide a heating film assembly and a battery pack for use in battery packs, so as to solve the problem that the structure of the heating film in the prior art is unreasonable and cannot ensure effective heating of the battery cells.

[0005] To achieve the above objectives, according to one aspect of the present invention, a heating film assembly for a battery pack is provided, comprising an adhesive layer, a first insulating layer, a second insulating layer, and a heating layer, wherein the adhesive layer is used to bond to a cold plate of the battery pack; the first insulating layer is connected to the side of the adhesive layer opposite to the cold plate; the second insulating layer is used to bond to the battery cell module of the battery pack by thermally conductive adhesive; the heating layer is sandwiched between the first insulating layer and the second insulating layer; wherein the thickness of the first insulating layer is not less than 0.2 mm.

[0006] In one exemplary embodiment, both the first insulating layer and the second insulating layer are polyester layers, and the thickness of the first insulating layer is greater than the thickness of the second insulating layer.

[0007] In an exemplary embodiment, in the direction away from the adhesive layer, the first insulating layer includes a first sub-insulating layer and a second sub-insulating layer connected together, and the thickness of the first sub-insulating layer is greater than the thickness of the second sub-insulating layer; and / or, in the direction away from the adhesive layer, the second insulating layer includes a third sub-insulating layer and a fourth sub-insulating layer connected together, and the thickness of the fourth sub-insulating layer is greater than the thickness of the third sub-insulating layer.

[0008] In an exemplary embodiment, in the direction away from the adhesive layer, the first insulating layer includes a first sub-insulating layer and a second sub-insulating layer connected together, and the thickness of the first sub-insulating layer is greater than the thickness of the second sub-insulating layer; in the direction away from the adhesive layer, the second insulating layer includes a third sub-insulating layer and a fourth sub-insulating layer connected together, and the thickness of the fourth sub-insulating layer is greater than the thickness of the third sub-insulating layer; wherein, the thickness of the first sub-insulating layer is greater than the thickness of the fourth sub-insulating layer.

[0009] According to another aspect of the present invention, a battery pack is provided, including a cell module, a heating film assembly, and a cold plate. The heating film assembly is sandwiched between the bottom of the cell module and the cold plate, and the heating film assembly is the aforementioned heating film assembly. The first adhesive strength between the cell module and the thermally conductive adhesive is P1, the second adhesive strength between the thermally conductive adhesive and the second insulating layer of the heating film assembly is P2, the third adhesive strength between the first insulating layer of the heating film assembly and the cold plate of the battery pack is P3, and the fourth adhesive strength between the adhesive layer of the heating film assembly and the cold plate is P4. The stress of the battery pack in the X, Y, and Z directions of the coordinate axes is F; wherein, 0.2 × P1 ≥ F.

[0010] In an exemplary embodiment, if 0.2×P2≥F, 0.2×P3≥F, and 0.2×P4<F, then the width L of the heating film assembly satisfies: P2×L / S≥F and P3×L / S≥F, where S is the width of the battery cell module; and / or, if 0.2×P2>F, 0.2×P3>F, and 0.2×P4≥F, then the width L of the heating film assembly has no effect on its structural strength; and / or, if 0.2×P2<F, 0.2×P3<F, and 0.2×P4>F, then the width L of the heating film assembly satisfies: 0.2×P4×(SL) / S≥F, where S is the width of the battery cell module.

[0011] In one exemplary embodiment, there are multiple heating film assemblies, each corresponding to one of the multiple cell modules of the battery pack, and the multiple heating film assemblies are connected in series sequentially via wires.

[0012] In one exemplary embodiment, there are multiple heating film assemblies, each corresponding to one of the multiple cell modules of the battery pack. Two adjacent heating film assemblies are connected in series via heating films. The width of the heating film is smaller than the width of the heating film assembly.

[0013] In an exemplary embodiment, in the extending direction of the heating film assembly, each heating film assembly has a first intermediate region and first edge regions located on both sides of the first intermediate region, wherein the power density of the same heating film assembly at the first edge regions on both sides is greater than the power density located at the first intermediate region; and / or, in the direction in which the plurality of heating film assemblies are arranged sequentially, the power density of each heating film assembly located at the second edge regions on both sides is greater than the power density of each heating film assembly located at the second intermediate region.

[0014] In an exemplary embodiment, each heating film assembly has a first intermediate region and first edge regions located on both sides of the first intermediate region in the extending direction of the heating film assembly, wherein the length of the heating film assembly located in the first edge regions on both sides is much smaller than the length of the heating film assembly located in the first intermediate region.

[0015] In an exemplary embodiment, in the direction in which the plurality of heating film assemblies are arranged in sequence, the length of each heating film assembly located at the second edge on both sides is greater than the length of each heating film assembly located in the second middle region.

[0016] In an exemplary embodiment, in the direction in which the plurality of heating film assemblies are arranged in sequence, the width of each heating film assembly located at the second edge on both sides is greater than the width of each heating film assembly located in the second middle region.

[0017] By applying the technical solution of this invention, the heating film assembly for the battery pack is configured with a structure comprising an adhesive layer, a first insulating layer, a second insulating layer, and a heating layer. Crucially, the thickness of the first insulating layer is not less than 0.2 mm. This design effectively addresses the risk of the heating film assembly being punctured by burrs on the cold plate, a problem present in existing technologies. The first insulating layer not only provides necessary electrical isolation but also resists damage from microburrs formed during the manufacturing and use of the cold plate, preventing safety issues such as short circuits. Simultaneously, by adjusting the design of the heating film assembly to ensure its lower layer is tightly bonded to the cold plate, the possibility of the heating film assembly burning out is reduced, ensuring the safety and stability of the heating process. Attached Figure Description

[0018] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0019] Figure 1 A partial cross-sectional view of a battery pack according to an alternative embodiment of the present invention is shown;

[0020] Figure 2 A cross-sectional view of a heating film assembly of a battery pack according to an alternative embodiment of the present invention is shown.

[0021] Figure 3 A cross-sectional schematic diagram of the heating film assembly of a battery pack according to another alternative embodiment of the present invention is shown;

[0022] Figure 4 A schematic diagram of the bottom structure of a heating film assembly and a battery cell module according to an optional embodiment of the present invention is shown. The diagram shows the power density in different regions of the heating film assembly.

[0023] Figure 5 A schematic diagram of the bottom structure of a heating film assembly and a battery cell module according to an optional embodiment of the present invention is shown. The diagram shows the dimensions of different regions of the heating film assembly.

[0024] Figure 6 A schematic diagram of the bottom structure of a heating film assembly and a battery cell module according to an optional embodiment of the present invention is shown. The diagram shows that two adjacent heating film assemblies are connected by a heating film.

[0025] The above figures include the following reference numerals:

[0026] 1. Cold plate; 101. Flow channel plate; 102. Flat plate; 2. Battery cell module; 3. Heating film assembly; 4. Thermally conductive adhesive; 5. Heating film; 6. Third insulating layer;

[0027] 10. Adhesive layer;

[0028] 20. First insulating layer; 21. First sub-insulating layer; 22. Second sub-insulating layer;

[0029] 30. Second insulating layer; 31. Third sub-insulating layer; 32. Fourth sub-insulating layer;

[0030] 40. Heating layer. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0032] To address the problem that the structure of existing heating films is unreasonable and cannot ensure effective heating of the battery cells, this invention provides a heating film assembly for a battery pack and a battery pack.

[0033] like Figures 1 to 6 As shown, the heating film assembly for the battery pack includes an adhesive layer 10, a first insulating layer 20, a second insulating layer 30, and a heating layer 40. The adhesive layer 10 is used to bond to the cold plate 1 of the battery pack; the first insulating layer 20 is connected to the side of the adhesive layer 10 away from the cold plate 1; the second insulating layer 30 is used to bond to the battery cell module 2 of the battery pack using thermally conductive adhesive 4; the heating layer 40 is sandwiched between the first insulating layer 20 and the second insulating layer 30; wherein the thickness of the first insulating layer 20 is not less than 0.2 mm.

[0034] By configuring the heating film assembly 3 for the battery pack into a structure comprising an adhesive layer 10, a first insulating layer 20, a second insulating layer 30, and a heating layer 40, with the key feature being that the thickness of the first insulating layer 20 is not less than 0.2 mm, this design effectively addresses the risk of the heating film assembly 3 being punctured by burrs on the cold plate, a problem present in existing technologies. The first insulating layer 20 not only provides necessary electrical isolation but also resists damage from microburrs formed during the manufacturing and use of the cold plate, preventing safety issues such as short circuits. Simultaneously, by adjusting the design of the heating film assembly 3 to ensure its lower layer is tightly bonded to the cold plate 1, the possibility of the heating film assembly 3 burning out is reduced, ensuring the safety and stability of the heating process.

[0035] like Figure 1 As shown, the cold plate 1 includes a flow channel plate 101 and a flat plate 102. The flow channel plate 101 has a groove, and the flat plate 102 covers the flow channel plate 101 and forms a refrigerant flow channel with the multiple grooves.

[0036] like Figure 2 As shown, both the first insulating layer 20 and the second insulating layer 30 are polyester layers, and the thickness of the first insulating layer 20 is greater than the thickness of the second insulating layer 30. Thus, by using polyester material for both the first insulating layer 20 and the second insulating layer 30, and designing the thickness of the first insulating layer 20 to be greater than that of the second insulating layer 30, this structural configuration not only effectively improves the electrical insulation performance between the heating film assembly 3 and the cold plate, but also significantly enhances the puncture resistance of the heating film assembly 3, reducing the risk of damage to the heating film assembly 3 caused by microburrs generated during the manufacturing and brazing of the cold plate, thereby ensuring the safe operation of the battery system. Furthermore, by using lower-cost polyester material, especially in the selection of the second insulating layer 30, the overall material cost is significantly reduced, achieving a balance between economy and functionality.

[0037] Furthermore, the different thicknesses of the first insulating layer 20 and the second insulating layer 30 allow the heating film assembly 3 to optimize the temperature distribution of the battery system and improve heating efficiency while ensuring critical requirements for electrical insulation and puncture resistance. Simultaneously, it achieves structural compactness and lightweight design, enhances the overall mechanical strength of the battery pack, and reduces the possibility of dry burning, providing a more comprehensive and economical solution for power battery thermal management. Of course, in other embodiments not shown in the figures, the first insulating layer 20 and the second insulating layer 30 may also use other types of insulating materials, as long as the performance improvement brought about by the thickness difference is met. This provides more flexibility and choice for practical applications.

[0038] like Figure 3 As shown, this embodiment is similar to Figure 2 The difference in the embodiments is that, in the direction away from the adhesive layer 10, the first insulating layer 20 includes a first sub-insulating layer 21 and a second sub-insulating layer 22 connected together, and the thickness of the first sub-insulating layer 21 is greater than the thickness of the second sub-insulating layer 22; and / or, in the direction away from the adhesive layer 10, the second insulating layer 30 includes a third sub-insulating layer 31 and a fourth sub-insulating layer 32 connected together, and the thickness of the fourth sub-insulating layer 32 is greater than the thickness of the third sub-insulating layer 31. Thus, for the design of the heating film assembly 3, we introduce a layered insulation structure, wherein the first insulating layer 20 is divided into a first sub-insulating layer 21 and a second sub-insulating layer 22, and the thickness of the first sub-insulating layer 21 is set to be greater than that of the second sub-insulating layer 22 to enhance protection against potential burrs and reduce the risk of insulation failure caused by minor defects formed during the cold plate manufacturing process. Simultaneously, the second insulating layer 30 is further subdivided into a third sub-insulating layer 31 and a fourth sub-insulating layer 32. The thickness of the fourth sub-insulating layer 32 is designed to be greater than that of the third sub-insulating layer 31, thereby optimizing the mechanical strength and electrical safety performance of the heating film assembly 3. Especially in situations requiring the resistance to significant external forces, this differentiated thickness design provides additional protection and support. Through the above structural design, the heating film assembly 3 can not only effectively avoid insulation failures caused by cold plate burrs, but also significantly improve the mechanical strength of the entire battery system, while ensuring the uniformity of cell heating and reducing the risk of dry burning. In addition, the power of the heating film assembly 3 is differentiated to adapt to the heating needs of different locations within the battery pack, further improving the efficiency and accuracy of temperature management. This innovative heating film assembly 3 structure and its arrangement, compared to existing technologies, achieves effective cost control while meeting the multiple requirements of the battery system for heating performance, mechanical strength, and safety. In other embodiments not shown in the figures, the heating film assemblies 3 can be connected in series using extremely narrow heating film assemblies 3 or wire harnesses to reduce the complexity of the bonding process, reduce bubble generation, and further optimize the production process. These design improvements together constitute an efficient, economical, and reliable battery thermal management solution.

[0039] like Figure 3 As shown, this embodiment is similar to Figure 2 The difference in the embodiments is that, in the direction away from the adhesive layer 10, the first insulating layer 20 includes a first sub-insulating layer 21 and a second sub-insulating layer 22 connected together, and the thickness of the first sub-insulating layer 21 is greater than the thickness of the second sub-insulating layer 22; in the direction away from the adhesive layer 10, the second insulating layer 30 includes a third sub-insulating layer 31 and a fourth sub-insulating layer 32 connected together, and the thickness of the fourth sub-insulating layer 32 is greater than the thickness of the third sub-insulating layer 31; wherein, the thickness of the first sub-insulating layer 21 is greater than the thickness of the fourth sub-insulating layer 32. Thus, the structural design of the heating film assembly 3 effectively improves the overall performance of the heating film assembly 3 by increasing the thickness difference between the first insulating layer 20 and the second insulating layer 30. Specifically, the first insulating layer 20 is composed of a first sub-insulating layer 21 and a second sub-insulating layer 22, wherein the thickness of the first sub-insulating layer 21 is greater than the thickness of the second sub-insulating layer 22; similarly, the second insulating layer 30 is composed of a third sub-insulating layer 31 and a fourth sub-insulating layer 32, wherein the thickness of the fourth sub-insulating layer 32 is greater than the thickness of the third sub-insulating layer 31. It is worth noting that the thickness of the first sub-insulating layer 21 is greater than that of the fourth sub-insulating layer 32. This design feature significantly enhances the puncture resistance of the heating film assembly 3 near the cold plate, effectively reducing the risk of insulation failure caused by burrs during the cold plate manufacturing process, while also reducing material costs. Furthermore, by adjusting the thickness of each sub-layer, the mechanical strength and adhesion performance of the heating film assembly 3 can be optimized, ensuring good contact between the cell and the cold plate, preventing dry burning, and further improving the safety and thermal management efficiency of the battery system. This innovative layered design strategy not only improves the reliability and economy of the heating film assembly 3 but also provides a more optimized solution for the thermal management system of directly cooled power batteries.

[0040] like Figure 1As shown, the battery pack includes a cell module 2, a heating film assembly 3, and a cold plate 1. The heating film assembly 3 is sandwiched between the bottom of the cell module 2 and the cold plate 1. The heating film assembly 3 is the heating film assembly described above and below. The first bonding strength between the cell module 2 and the thermally conductive adhesive 4 is P1. The second bonding strength between the thermally conductive adhesive 4 and the second insulating layer 30 of the heating film assembly 3 is P2. The third bonding strength between the first insulating layer 20 of the heating film assembly 3 and the cold plate 1 of the battery pack is P3. The fourth bonding strength between the adhesive layer 10 of the heating film assembly 3 and the cold plate 1 is P4. The stress of the battery pack in the X, Y, and Z directions of the coordinate axis is F. Wherein, 0.2 × P1 ≥ F. In this way, the cell module 2 and the thermally conductive adhesive 4 are reliably connected through the first adhesive strength P1, ensuring that the cell can be firmly fixed in the battery pack even under extreme conditions. The ratio of 0.2×P1≥F effectively manages the stress of the battery pack in the X, Y, and Z directions, enhancing the stability and durability of the entire battery system. The thermally conductive adhesive 4 is connected to the second insulating layer 30 of the heating film assembly 3 through the second adhesive strength P2, while the third adhesive strength P3 between the first insulating layer 20 of the heating film assembly 3 and the cold plate 1 ensures a tight bond between the heating assembly and the cold plate. The adhesive strength requirements of these two are 0.2×P2 and 0.2×P3≥F, which further strengthens the integrity of the internal structure of the battery pack and reduces the decrease in thermal efficiency caused by loose components. The fourth bonding strength P4 between the adhesive layer 10 of the heating film assembly 3 and the cold plate 1 is set to 0.2 × P4 ≥ F. This condition is crucial for maintaining the overall mechanical strength of the battery pack, especially when the width L of the heating film assembly 3 is close to the width S of the battery cell. This ensures that even if the width of the heating film assembly 3 increases, it will not negatively affect the mechanical strength of the battery pack. The implementation of this technical solution not only reduces the risk of the heating film assembly 3 being punctured but also ensures the structural stability of the battery pack under mechanical impact. Furthermore, by optimizing the differentiated power design of the heating film assembly 3, the uniformity of the battery cell temperature inside the battery pack is effectively improved, further enhancing the overall efficiency and lifespan of the battery system.

[0041] It should be noted that, in this application, if 0.2×P2≥F, 0.2×P3≥F, and 0.2×P4<F, then the width L of the heating film assembly 3 satisfies: P2×L / S≥F and P3×L / S≥F, where S is the width of the battery cell module 2; and / or, if 0.2×P2>F, 0.2×P3>F, and 0.2×P4≥F, then the width L of the heating film assembly 3 has no effect on its structural strength; and / or, if 0.2×P2<F, 0.2×P3<F, and 0.2×P4>F, then the width L of the heating film assembly 3 satisfies: 0.2×P4×(SL) / S≥F, where S is the width of the battery cell module 2.

[0042] Specifically, when the bonding strength P1 between the battery cell and the structural (thermal conductive) adhesive, the bonding strength P2 between the structural thermal conductive adhesive and the upper layer of the heating film assembly 3, the bonding strength P3 between the lower layer of the heating film assembly 3 and the cold plate, and the bonding strength P4 between the structural (thermal conductive) adhesive and the cold plate meet specific conditions, the width L of the heating film assembly 3 must be designed according to the corresponding formula. Specifically, if 0.2×P2 and 0.2×P3 are both greater than or equal to the stress F of the battery pack in the X, Y, and Z directions, while 0.2×P4 is less than F, then the width L of the heating film assembly 3 must satisfy that P2×L / S and P3×L / S are both greater than or equal to F, where S is the width of the battery cell module 2. This design ensures the electrical insulation and structural strength between the battery cell module and the heating film assembly 3, while reducing the risk of the heating film assembly 3 being punctured by burrs on the cold plate. Alternatively, when 0.2×P2 and 0.2×P3 are both greater than F, and 0.2×P4 is also greater than or equal to F, the width L of the heating film assembly 3 has no significant impact on the structural strength of the system. In this case, the width of the heating film assembly 3 can be adjusted more flexibly to optimize cost or heating efficiency. Finally, if 0.2×P2 and 0.2×P3 are both less than F, but 0.2×P4 is greater than F, then the width L of the heating film assembly 3 must satisfy 0.2×P4×(SL) / S greater than or equal to F. In this case, by adjusting the width of the heating film assembly 3, it can be ensured that even if the bonding strength between the heating film assembly 3 and the cold plate is low, it can be compensated for by enhancing the bonding force between the heating film assembly 3 and the structural (thermal conductive) adhesive, thereby ensuring the mechanical strength and insulation performance of the entire battery system. The above design principles and formulas provide a scientific basis for the width design of the heating film assembly 3, which helps to achieve a balance between mechanical strength, cost control, and heating performance of the battery pack. In other embodiments not shown in the figure, the connection between the heating film assemblies 3 can also be achieved by connecting the heating film assemblies 3 with extremely narrow connections, or by placing the heating film assembly 3 independently for each module and optimizing the connection through a series wiring harness. This further reduces the difficulty of the bonding process, minimizes bubble formation, and improves system reliability and production efficiency. These alternative solutions provide more options for the integration of direct-cooling film heating systems, ensuring that the heating film assembly 3 can operate effectively under different conditions, while reducing the risk of dry burning and improving temperature uniformity between battery cells.

[0043] like Figure 4 and Figure 5As shown, there are multiple heating film assemblies 3, each corresponding one-to-one with a different battery cell module 2 in the battery pack. These heating film assemblies 3 are connected in series sequentially via wires. This design, with multiple heating film assemblies 3 corresponding one-to-one with each battery cell module 2 in the battery pack, allows for independent and precise temperature control for each battery cell module. The sequential series connection of the multiple heating film assemblies 3 simplifies the circuit layout and ensures system stability and consistency. In practical applications, the series-connected heating film assemblies 3 can distribute current according to the actual needs of the battery cell modules, thereby controlling the heating power in different areas and effectively improving heating efficiency and temperature uniformity. Furthermore, the series connection reduces the overall energy consumption and cost of the system, as only one power input point is needed to control the entire heating system, reducing external connection points and circuit complexity. This design meets the requirements of the battery thermal management system while also improving system reliability and economy. Of course, in other embodiments not shown, the heating film assembly 3 can also be connected in parallel to adapt to different heating requirements and battery pack designs, further optimizing the temperature control strategy and improving the system's flexibility.

[0044] like Figure 6 As shown, there are multiple heating film assemblies 3, each corresponding one-to-one with a cell module 2 in the battery pack. Adjacent heating film assemblies 3 are connected in series via heating film 5; the width of heating film 5 is smaller than the width of heating film assembly 3. This allows for multiple arrangement schemes of the heating film assemblies 3, with each assembly corresponding to one cell module 2 in the battery pack, providing precise thermal management. The series connection of adjacent heating film assemblies 3 via narrower heating film 5 simplifies the manufacturing process, reduces material usage in the connection area, thus lowering costs, and also ensures overall heating uniformity and efficiency. The smaller width of heating film 5 compared to heating film assembly 3 effectively prevents heat diffusion during cell thermal runaway while ensuring rapid heat conduction on the direct cooling plate, enhancing the system's thermal management capabilities. By controlling the width of heating film 5, the power density distribution of the heating film assembly 3 can be optimized while ensuring electrical insulation and preventing mechanical damage, further improving the temperature uniformity of the battery system and ensuring the battery's stability and safety under different ambient temperatures. This design also considers the stress requirements of the battery pack in the X, Y, and Z directions. By reasonably adjusting the width of the heating film assembly 3 and the connection method of the heating film 5, the mechanical strength of the battery system is ensured, and the risk of dry burning is reduced. Overall, this solution has significant improvements and advantages in cost control, mechanical strength assurance, thermal management efficiency, and safety.

[0045] like Figures 4 to 6As shown, in the extending direction of the heating film assembly 3, each heating film assembly 3 has a first intermediate region and first edge regions located on both sides of the first intermediate region. The power density of the same heating film assembly 3 at the first edge regions on both sides is greater than the power density at the first intermediate region. And / or, in the direction in which multiple heating film assemblies 3 are arranged sequentially, the power density of each heating film assembly 3 located at the second edge regions on both sides is greater than the power density of each heating film assembly 3 located at the second intermediate region. Thus, by optimizing the power density layout of the heating film assemblies 3, better temperature uniformity can be provided, especially in multi-module battery packs, effectively reducing the temperature difference between cells and improving the overall performance and lifespan of the battery system. In summary, this technical solution significantly improves the heating efficiency and reliability of the battery system while ensuring safety, and simultaneously reduces costs, achieving more economical and efficient battery thermal management.

[0046] Specifically, this application optimizes the power density design of the heating film assembly 3. In its extension direction, the heating film assembly 3 is divided into a first intermediate region and two first edge regions on either side, with the power density of the first edge regions set to be greater than that of the first intermediate region. This design effectively improves the heating efficiency of the edge cells in the battery pack, reduces temperature differences within the entire battery pack, and ensures a more uniform temperature distribution. Simultaneously, in the direction where multiple heating film assemblies 3 are arranged sequentially, the heating film assemblies 3 located at the two ends of the second edge region have a higher power density, while the heating film assemblies 3 located in the central second intermediate region have a lower power density. This layout strategy aims to enhance the heating efficiency of the external cells to address the temperature gradient problem caused by edge heat dissipation, thereby improving the heating uniformity and thermal management efficiency of the entire battery pack. Through the above differentiated power density configuration, not only is the overall working efficiency of the heating film assembly 3 improved, but the cost control and safety performance of the battery system are also taken into account, achieving an effective balance between heating efficiency and temperature uniformity. Of course, in addition to the above design, other power density distribution modes can be explored, such as using nonlinear distribution or dynamically adjusting the power density to adapt to the thermal management requirements under different environmental conditions, further enhancing the flexibility and applicability of the solution. In other embodiments not shown in the figure, the power density of the heating film assembly 3 can be customized according to the specific location and thermal characteristics of the battery cell to achieve the best thermal management effect.

[0047] like Figures 4 to 6As shown, the heating films W1, W3, W4, W6, W7, and W9 near the outer edge of the battery pack have higher power densities, while the heating films W2, W5, and W8 in the middle area have lower power densities. This arrangement aims to reduce the temperature difference between the cells, improve the temperature uniformity of the battery thermal management system, and thus improve the overall thermal performance and extend the lifespan of the battery pack. By comprehensively considering cost, insulation performance, mechanical strength, and temperature uniformity, this embodiment provides an efficient and economical battery thermal management solution. It not only optimizes the performance of the heating films but also optimizes the battery system integration through the rational design of the heating film width and power density, ensuring stable operation and safety of the battery under various environmental conditions. Of course, in other embodiments not shown in the figure, the heating films can also be connected in series through extremely narrow connecting strips, or a heating film can be placed independently under each module. These variant solutions can also effectively achieve the heating film arrangement and design goals, but specific analysis and adjustments are required based on different application scenarios and needs.

[0048] It should be noted that in this application, the heating film sizes also differ for different power densities.

[0049] like Figures 4 to 6 As shown, in the extending direction of the heating film assembly 3, each heating film assembly 3 has a first intermediate region and first edge regions located on both sides of the first intermediate region. The length of the heating film assembly 3 located in the first edge regions on both sides is much shorter than the length of the heating film assembly 3 located in the first intermediate region. Thus, the design of the heating film assembly 3 divides the extending direction into a first intermediate region and first edge regions on both sides, with the length of the first edge regions being much shorter than the length of the first intermediate region. This structural arrangement allows for targeted control of the power density distribution of the heating film assembly 3, enabling it to provide more concentrated heat in the peripheral area of ​​the battery module, while the heat distribution in the intermediate area is relatively uniform. This differentiated power design effectively reduces the temperature difference between the outer and middle cells of the battery module, ensuring cell temperature uniformity and thus improving the overall performance and lifespan of the battery system. Simultaneously, this design also considers the expansion of the cells during charging and discharging, avoiding the risk of dry burning of the heating film assembly 3 due to cell expansion, further enhancing the reliability and safety of the system. Of course, in other embodiments not shown, the power density distribution and area division of the heating film assembly 3 can be adjusted according to the specific needs of the battery system to achieve the best heating effect and cost control.

[0050] Specifically, such as Figure 5As shown, when the power density of the heating film is designed so that the area near the outer edge is higher than the middle area, not only is efficient heating of the battery system achieved, but the uniformity of temperature distribution is further optimized by adjusting the size of the heating film in different power density areas. Specifically, the heating film width L is correspondingly increased in the W1, W3, W4, W6, W7, and W9 areas with higher power densities. This helps to quickly raise the temperature at the edge of the battery pack and reduce the temperature gradient. In contrast, the heating film width L is smaller in the W2, W5, and W8 areas with lower power densities. This ensures the heating needs of the central area while avoiding unnecessary energy waste and improving the energy utilization efficiency of the entire system. In addition, to achieve better thermal conductivity, the heating film length in the M1, M3, N1, and N3 areas is much greater than that in the M2 and N2 areas. At the same time, the heating film length in the L1 and L3 areas significantly exceeds that in the T2 area. This design ensures sufficient contact between the battery cell and the heating film, reduces thermal resistance, and improves temperature uniformity. Through this differentiated design of power density and heating film size, the battery thermal management system can more effectively cope with changes in the external environment, maintain an ideal temperature state inside the battery pack, extend battery life, and ensure safe battery operation. Of course, in other embodiments not shown, the heating films can be connected in series via extremely narrow connecting strips, which reduces material usage, simplifies the manufacturing process, and lowers production costs.

[0051] like Figures 4 to 6 As shown, in the direction in which multiple heating film components 3 are arranged sequentially, the length of each heating film component 3 located at the second edge on both sides is greater than the length of each heating film component 3 located in the second middle region. This design optimizes the layout of the heating film components 3, improving the heating efficiency in the edge region and effectively addressing the issue of rapid heat dissipation in the cell edge area, thereby improving the temperature uniformity of the entire battery system. By increasing the length of the edge heating film components 3, a more balanced temperature distribution of the cell can be ensured in the width direction of the battery system, avoiding increased temperature differences in the cells due to edge heat dissipation, thus enhancing the overall performance and lifespan of the battery system. Furthermore, this layout reduces the series resistance between the heating film components 3, improving heating efficiency and reducing energy consumption. In practical applications, this design allows for flexible adjustment of the length ratio of the heating film components 3 to adapt to the thermal management requirements of different cell models, demonstrating good versatility and adaptability. Of course, in other embodiments not shown in the figure, the length difference of the heating film assembly 3 can be customized according to the specific application scenario and the layout of the battery cell, further improving the efficiency and economy of the battery thermal management system.

[0052] like Figures 4 to 5 As shown, in the direction in which multiple heating film components 3 are arranged sequentially, the width of each heating film component 3 located at the second edges on both sides is greater than the width of each heating film component 3 located in the second middle region. Thus, when multiple heating film components 3 are arranged sequentially, the width L of the heating film components 3 located at the second edges on both sides is greater than the width of the heating film components 3 located in the second middle region. This design aims to optimize the heat distribution in the thermal management system. By adjusting the width of the heating film components 3, the heating power density of the edge cells can be increased specifically, thereby reducing temperature differences between cells. Especially under extreme environmental conditions, edge cells may be more susceptible to external temperature influences. By increasing the width of the heating film components 3 below them, the temperature of these cells can be effectively increased, ensuring the temperature uniformity of the entire battery system. Furthermore, this differentiated design can also reduce costs to some extent, because it is not necessary to use the same material thickness and specifications for all heating film components 3; adjustments can be made flexibly according to actual needs. Of course, in other embodiments not shown, the power density and size of the heating film components 3 can also be customized according to the specific layout and temperature control requirements of the cells to achieve optimal heating effect and system integration efficiency. This solution not only improves the thermal management performance of the battery system, but also enhances mechanical strength and reduces the risk of the heating film assembly 3 being dry-burned or punctured by the cold plate burrs, demonstrating good overall benefits.

[0053] When using the battery pack of this application, firstly, an adhesive layer 10 is laid on the upper surface of the cold plate 1. This adhesive layer 10 is used to enhance the adhesion between the heating film assembly 3 and the cold plate, while providing necessary insulation protection. Subsequently, a first insulating layer 20 with a specific structure is placed on the adhesive layer 10. The thickness of the first insulating layer 20 is not less than 0.2 mm to ensure sufficient electrical isolation and resistance to minor burrs that may form during the cold plate manufacturing process. Next, a heating layer 40 is placed on the first insulating layer 20. The heating layer 40 is typically made of materials such as copper sheets, steel sheets, or graphene and is used to generate heat. To further enhance the safety and efficiency of the system, a second insulating layer 30 is placed on the heating layer 40 to isolate the cell module 2. The material and thickness of the second insulating layer 30 must meet the requirements of cell heating and cost considerations. The cell module 2 is connected to the second insulating layer 30 through thermally conductive adhesive 4. The thermally conductive adhesive not only provides electrical insulation but also transfers the heat generated by the cell to the cold plate. The entire heating film assembly 3 is stacked and tightly connected together to form a complete and efficient thermal management system for temperature control of the battery pack. In actual operation, by controlling the width L of the heating film assembly 3, the appropriate heating power density of the cells in different areas is ensured. Simultaneously, considering the stress requirements of the battery pack in the X, Y, and Z directions, the mechanical performance is optimized by adjusting the adhesion strength between each layer. Furthermore, the heating film assemblies 3 can be connected in series via wires or through narrower heating films 5 to achieve uniform heating and cost savings.

[0054] Throughout its use, the power density design, width adjustment, and material selection of each layer of the heating film assembly 3 are all based on the goals of improving the thermal management efficiency of the battery system, reducing the risk of dry burning, and enhancing temperature uniformity, while also considering cost-effectiveness and mechanical strength optimization. The implementation of these technical measures effectively improves the overall performance of the power battery thermal management system. When the heating film assembly 3 is working, the heat generated by the heating layer 40 is uniformly conducted to the cell module, and simultaneously dissipated rapidly through the refrigerant channels of the cold plate 1, achieving precise control and uniform distribution of the internal temperature of the battery pack. Regarding the width design of the heating film assembly 3, if 0.2 times P2 and P3 are greater than the stress of the battery pack in the XYZ directions, the width of the heating film assembly 3 can be determined based on P2×L / S and P3×L / S, ensuring that it provides sufficient heat conduction area without adversely affecting the mechanical strength of the battery pack. Conversely, if 0.2 times P2 and P3 is less than the stress of the battery pack in the XYZ direction, while 0.2 times P4 needs to be greater than the stress of the battery pack in the XYZ direction, the width of the heating film assembly 3 must meet the requirement of 0.2 × P4 × (SL) / S ≥ F, where S is the width of the cell module. This design principle ensures that the heating film assembly 3 meets mechanical strength requirements while effectively controlling the heating process of the cell, avoiding dry burning, and providing good temperature uniformity. In the entire battery thermal management system, the connection method, power density design, and width adjustment of each heating film assembly 3 work together to improve the thermal management efficiency of the battery pack, reduce costs, and enhance the safety and reliability of the system, demonstrating a technological innovation in the field of power battery thermal management. Inside the battery pack, the careful matching of parameters such as the bonding strength between the cell module 2 and the thermally conductive adhesive 4, the bonding strength between the thermally conductive adhesive and the second insulating layer 30 of the heating film assembly 3, the bonding strength between the first insulating layer 20 of the heating film assembly 3 and the cold plate, and the bonding strength between the adhesive layer 10 of the heating film assembly 3 and the cold plate ensures that the battery pack maintains structural stability and electrical safety even under stress in the X, Y, and Z directions. In terms of the specific arrangement of the heating film assemblies 3, at least one heating film assembly 3 is placed below each cell module to directly heat the cell. Simultaneously, the heating film assemblies 3 can be connected in series via wiring harnesses to form a unified heating network.

[0055] To optimize heating efficiency and temperature distribution, the heating film assembly 3 is distributed within the battery pack using a differentiated power density design. The power density in the edge areas of the cell modules is higher than in the center areas to compensate for potential temperature gradients caused by faster heat dissipation in the edge cells. This layout strategy not only improves temperature uniformity but also reduces the width requirement of the heating film assembly 3, decreasing material consumption and thus lowering costs while improving heating efficiency. Regarding the width and length design of the heating film assembly 3, the edge areas have greater widths or lengths to increase the heating power density of the edge cells, ensuring temperature consistency throughout the battery pack. Through these design and technical measures, the direct-cooling power battery thermal management system of this application effectively controls costs while ensuring cell heating uniformity and safety, and improves the mechanical strength of the battery pack, demonstrating technological innovation in the field of power battery thermal management. When the system is running, each heating film assembly 3, based on the heating requirements of its corresponding cell module, controls the power of the heating layer 40 to achieve precise temperature regulation. Through the tight bonding of the adhesive layer 10 to the cold plate, the effective connection between the heating film assembly 3 and the cell module, and the uniform heating network formed by the series connection of the heating film assemblies 3, the entire system can ensure a uniform temperature distribution among the cells inside the battery pack while providing sufficient mechanical strength to cope with the stress in the XYZ directions of the battery pack. This optimization measure not only improves heating efficiency and reduces the risk of dry burning, but also achieves precise heating of cells in different areas inside the battery pack by adjusting the width and length of the heating film assembly 3, thereby effectively solving the problem of large temperature differences between cells and enhancing the overall stability and safety of the battery system.

[0056] In practical applications, the connection strength between the heating film assembly 3 and the cold plate must meet specific conditions to ensure that the mechanical strength of the battery pack is not affected even when the width of the heating film assembly 3 increases. The power density design of the heating film assembly 3 fully considers the heating needs of each area of ​​the battery pack. The heating film assembly 3 in the edge area has a higher power density to compensate for the rapid heat dissipation of the edge cells, thereby achieving a uniform increase in cell temperature. Through the implementation of the above technical solutions, the entire direct-cooling power battery thermal management system achieves a good balance between mechanical strength, cost control, heating efficiency, and temperature uniformity, providing a comprehensive and reliable thermal management solution for power batteries. When the system starts the heating process, the heating layer 40 begins to convert electrical energy into heat energy, and transfers the heat to the cell module 2 through the first insulating layer 20 and the second insulating layer 30. At the same time, the adhesive layer 10 and the refrigerant channels of the cold plate 1 work together to ensure temperature control and heat dissipation during the heating process. When the battery pack is subjected to external forces, the bonding strength between the layers of materials ensures the structural stability of the system and the fixation of the cell modules. Especially when P4 is 0.2 times greater than the stress in the XYZ direction of the battery pack, even if the width L of the heating film assembly 3 increases, it does not affect the mechanical strength of the battery pack. By adjusting the width and length of the heating film assembly 3 and optimizing the power density distribution, the direct-cooling power battery thermal management system provided in this application achieves efficient, safe, and low-cost battery heating and temperature management, providing important technical support for the optimization of electric vehicle battery systems. Throughout the battery pack's operating cycle, the heating film assembly 3 heats the cells through energy conversion via the heating layer 40, according to the specific needs of the cell modules. During this process, the first insulating layer 20 and the second insulating layer 30 not only provide electrical isolation but also effectively prevent the heating film assembly 3 from being punctured by burrs on the cold plate, thereby avoiding insulation failures and improving system safety. The adhesive layer 10 between the heating film assembly 3 and the cold plate enhances the heat transfer efficiency between them while ensuring stable adhesion of the heating film assembly 3 to the surface of the cold plate. Between the battery cell module and the heating film assembly 3, the thermally conductive adhesive plays a good role in heat conduction and adhesion, ensuring a tight connection between the battery cell and the heating film assembly 3 and reducing heat loss caused by poor contact.

[0057] The width design of the heating film assembly 3 follows specific formula constraints to meet the mechanical strength requirements of the battery pack and avoid affecting the overall performance of the battery pack due to changes in the width of the heating film assembly 3. By adjusting the power density and width of the heating film assembly 3 in different areas of the battery pack, effective temperature balance of the cells is achieved, reducing the temperature difference between cells and improving the overall efficiency and reliability of the battery system. During operation, the entire system can not only precisely control the heating process of the cells to prevent dry burning, but also effectively improve the heat exchange efficiency between the cell modules and the cold plate, ensuring the stable operation of the battery pack under various environmental conditions, demonstrating a technological breakthrough in the field of power battery thermal management. When the heating film assembly 3 is working, the heat generated by the heating layer 40 is first transferred to the thermally conductive adhesive 4 through the second insulating layer 30, and then conducted to the cell module 2 by the thermally conductive adhesive to heat the cells. At the same time, the first insulating layer 20 conducts heat from the heating layer 40 to the cold plate 1, using the refrigerant channels of the cold plate for heat dissipation. During this process, the adhesive layer 10 enhances the adhesion between the heating film assembly 3 and the cold plate, ensuring the stability and positional accuracy of the heating film assembly 3. By adjusting the width and power density of the heating film assembly 3, the system can provide customized heating services according to the thermal requirements of different areas of the battery cell, reducing temperature unevenness and improving battery efficiency and lifespan.

[0058] During the system design phase, optimization of the bonding strength of each layer of materials, such as controlling the bonding strength between the battery cell and the thermally conductive adhesive, between the thermally conductive adhesive and the heating film assembly 3, and between the heating film assembly 3 and the cold plate, ensures that the battery pack maintains structural integrity and thermal management performance even under extreme conditions. The series connection between the heating film assemblies 3 allows the entire system to control the operation of all heating film assemblies 3 through a single power point, simplifying circuit layout and reducing energy consumption and cost. In practical applications, the width design of the heating film assembly 3 follows a specific formula to match the mechanical strength requirements of the battery pack, while reducing material waste and achieving economical and efficient operation. When the system is running, each heating film assembly 3 heats the battery cell according to the heating needs of the battery cell module at its location through temperature changes in the heating layer 40. The first insulating layer 20 and the second insulating layer 30 not only provide electrical isolation...

[0059] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0060] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0061] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0062] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0063] It should be noted that the terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in sequences other than those illustrated or described herein.

[0064] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A heating film assembly for a battery pack, characterized in that, include: Adhesive layer (10), said adhesive layer (10) is used to bond to the cold plate (1) of the battery pack; The first insulating layer (20) is connected to the side of the adhesive layer (10) away from the cold plate (1); The second insulating layer (30) is used to bond the battery cell module (2) of the battery pack with thermally conductive adhesive (4); A heating layer (40) is sandwiched between the first insulating layer (20) and the second insulating layer (30); The thickness of the first insulating layer (20) is not less than 0.2 mm.

2. The heating film assembly according to claim 1, characterized in that, Both the first insulating layer (20) and the second insulating layer (30) are polyester layers, and the thickness of the first insulating layer (20) is greater than the thickness of the second insulating layer (30).

3. The heating film assembly according to claim 1, characterized in that, In the direction away from the adhesive layer (10), the first insulating layer (20) includes a first sub-insulating layer (21) and a second sub-insulating layer (22) connected together, and the thickness of the first sub-insulating layer (21) is greater than the thickness of the second sub-insulating layer (22); and / or, In the direction away from the adhesive layer (10), the second insulating layer (30) includes a third sub-insulating layer (31) and a fourth sub-insulating layer (32) connected together, and the thickness of the fourth sub-insulating layer (32) is greater than the thickness of the third sub-insulating layer (31).

4. The heating film assembly according to claim 1, characterized in that, In the direction away from the adhesive layer (10), the first insulating layer (20) includes a first sub-insulating layer (21) and a second sub-insulating layer (22) connected together, and the thickness of the first sub-insulating layer (21) is greater than the thickness of the second sub-insulating layer (22); In the direction away from the adhesive layer (10), the second insulating layer (30) includes a third sub-insulating layer (31) and a fourth sub-insulating layer (32) connected together, and the thickness of the fourth sub-insulating layer (32) is greater than the thickness of the third sub-insulating layer (31); The thickness of the first sub-insulating layer (21) is greater than the thickness of the fourth sub-insulating layer (32).

5. A battery pack, characterized in that, include: The battery cell module (2), the heating film assembly (3) and the cold plate (1) are provided, wherein the heating film assembly (3) is sandwiched between the bottom of the battery cell module (2) and the cold plate (1), and the heating film assembly (3) is the heating film assembly according to any one of claims 1 to 4; The first bonding strength between the cell module (2) and the thermally conductive adhesive (4) is P1, the second bonding strength between the thermally conductive adhesive (4) and the second insulating layer (30) of the heating film assembly (3) is P2, the third bonding strength between the first insulating layer (20) of the heating film assembly (3) and the cold plate (1) of the battery pack is P3, the fourth bonding strength between the adhesive layer (10) of the heating film assembly (3) and the cold plate (1) is P4, and the stress of the battery pack in the X, Y, and Z directions of the coordinate axis is F. Wherein, 0.2×P1≥F.

6. The battery pack according to claim 5, characterized in that, If 0.2×P2≥F, 0.2×P3≥F, and 0.2×P4<F, then the width L of the heating film assembly (3) satisfies: P2×L / S≥F and P3×L / S≥F, where S is the width of the battery cell module (2); and / or, If 0.2×P2>F, 0.2×P3>F, and 0.2×P4≥F, then the width L of the heating film assembly (3) has no effect on its structural strength; and / or, If 0.2×P2<F, 0.2×P3<F, and 0.2×P4>F, then the width L of the heating film assembly (3) satisfies: 0.2×P4×(SL) / S≥F, where S is the width of the battery cell module (2).

7. The battery pack according to claim 5, characterized in that, There are multiple heating film assemblies (3), and each heating film assembly (3) corresponds to a multiple cell module (2) of the battery pack. The multiple heating film assemblies (3) are connected in series sequentially by wires.

8. The battery pack according to claim 5, characterized in that, There are multiple heating film assemblies (3), and each of the multiple heating film assemblies (3) is used to correspond one-to-one with multiple battery cell modules (2) of the battery pack. Two adjacent heating film assemblies (3) are connected in series through a heating film (5). The width of the heating film (5) is smaller than the width of the heating film assembly (3).

9. The battery pack according to any one of claims 5 to 8, characterized in that, In the extending direction of the heating film assembly (3), each heating film assembly (3) has a first intermediate region and first edge regions located on both sides of the first intermediate region, wherein the power density of the same heating film assembly (3) at the first edge regions on both sides is greater than the power density located at the first intermediate region; and / or, In the direction in which the plurality of heating film assemblies (3) are arranged in sequence, the power density of each heating film assembly (3) located at the second edge region on both sides is greater than the power density of each heating film assembly (3) located at the second middle region.

10. The battery pack according to any one of claims 5 to 8, characterized in that, In the extending direction of the heating film assembly (3), each heating film assembly (3) has a first intermediate region and a first edge region located on both sides of the first intermediate region, wherein the length of the heating film assembly (3) located on both sides of the first edge region is much smaller than the length of the heating film assembly (3) located in the first intermediate region.

11. The battery pack according to any one of claims 5 to 8, characterized in that, In the direction in which the plurality of heating film assemblies (3) are arranged in sequence, the length of each heating film assembly (3) located at the second edge on both sides is greater than the length of each heating film assembly (3) located in the second middle region.

12. The battery pack according to any one of claims 5 to 8, characterized in that, In the direction in which the plurality of heating film assemblies (3) are arranged in sequence, the width of each heating film assembly (3) located at the second edge on both sides is greater than the width of each heating film assembly (3) located in the second middle region.

Images