PI heating film elastic system assembly and battery pack

Abstract

The utility model discloses a PI heating film elasticity system assembly and battery pack, wherein the PI heating film elasticity system assembly includes oppositely arranged insulating films, a back adhesive layer arranged outside any one of the insulating films, and a resistance wire arranged between two layers of the insulating films, the top and bottom of the insulating film are alternately provided with deformation sections along the length direction, the deformation sections separate the insulating film into a plurality of layout areas, the resistance wire in the layout area forms a heating part, the heating parts are arranged in series, and the resistance wire for the series heating part is located in the corresponding deformation section and is fitted with the cross-sectional shape of the deformation section, the deformation section extends along the width direction of the insulating film, and a gap is arranged between the two adjacent deformation sections along the width direction of the insulating film. The utility model ensures that the heating film is always attached to the surface of the battery cell and does not cause tearing risk, avoids the risk of breaking the resistance wire of the deformation section when the heating film retracts, and has simple structure and strong practicality.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, and in particular to a PI heating film elastic system assembly and battery pack. Background Technology

[0002] With the development of new energy technologies, battery thermal management is receiving increasing attention. In low-temperature environments, to ensure normal charging and discharging, the battery cells need to be heated. The industry typically uses heating films or liquid heating solutions. Among these, the heating film solution is increasingly adopted by battery manufacturers due to its simple structure and significant cost advantages. The heating film is usually bonded to the cell surface using adhesive. Because the heating film is flat, the cell expands and deforms during charge-discharge cycles. If the adhesive strength is weak, shearing occurs between the cell's sidewalls and the heating film, causing relative slippage and preventing the heating film from fully adhering to the cell surface, thus reducing its utilization rate. If the adhesive strength is strong, the heating film deforms along with the cell's expansion and deformation, potentially leading to tearing of the heating film's resistance wires and causing the heating film to fail.

[0003] Chinese utility model patent application CN 222581286 U discloses an adaptive heating film, comprising an insulating film and a resistance wire. Both ends of the resistance wire are provided with wire harnesses and terminals connected to the wire harnesses. The insulating film has two layers arranged in a front-to-back orientation. One side of the insulating film has an adhesive layer for bonding the battery core. The resistance wire is positioned between the two insulating film layers. Multiple evenly spaced deformable segments are provided on the insulating film, with planar segments between adjacent deformable segments. The upper and lower ends of each deformable segment extend to the upper and lower ends of the insulating film, respectively. The deformable segments on the two insulating film layers are arranged in a front-to-back orientation. The resistance wire has curved segments at positions corresponding to the deformable segments, and these curved segments are arranged in a continuous S-shape horizontally within the planar segments. In this structural design, by pre-setting the bending section of the resistance wire and the deformation section of the insulating film, the actual length of the heating film can be freely stretched and contracted to follow the expansion of the battery cell to a certain extent, thereby obtaining a longer actual service life and a higher utilization rate. However, due to the large length of the deformation section and the large overall deformation area, it is difficult to maintain excellent reset ability after deformation and retraction. Therefore, during retraction, the resistance wire in this area is prone to secondary bending, which may lead to breakage risk. Utility Model Content

[0004] The purpose of this invention is to address the shortcomings of existing technologies by proposing a PI heating film elastic system assembly and battery pack. This assembly ensures that the heating film always adheres to the surface of the battery cell without the risk of tearing, while also preventing the risk of the resistance wire in the deformed section from breaking when the heating film retracts. The structure is simple and highly practical.

[0005] The technical solution to achieve the purpose of this utility model is:

[0006] A PI heating film elastic system assembly includes an insulating film disposed opposite to each other, an adhesive backing layer disposed on the outside of any one of the insulating films, and a resistance wire disposed between the two insulating films. The top and bottom of the insulating film are alternately provided with deformable sections along the length direction. The deformable sections divide the insulating film into multiple distribution areas. The resistance wires located in the distribution areas form heating parts. The heating parts are arranged in series, and the resistance wires used for the series heating parts are located in the corresponding deformable sections and conform to the cross-sectional shape of the deformable sections. The deformable sections extend along the width direction of the insulating film, and a gap is provided between two adjacent deformable sections along the width direction of the insulating film.

[0007] Furthermore, the deformed segment is an arched buffer strip that protrudes toward the side away from the adhesive layer.

[0008] Furthermore, the insulating film has a strip-shaped through groove aligned with the deformed section.

[0009] Furthermore, a notch is provided on the side of the strip groove away from the deformed section, which is aligned with the edge of the insulating film, thereby forming a weak connection point between the notch and the strip groove.

[0010] Furthermore, the notch is an arc-shaped gap, and the end of the strip-shaped through groove near the notch is also an arc-shaped structure.

[0011] Furthermore, the resistance wires located in the deployment area are arranged in a continuous S-shape along the longitudinal direction.

[0012] Furthermore, the cross-sectional area of ​​the resistance wire located in the deformation section is larger than that of the resistance wire located in the deployment area.

[0013] A battery pack includes a battery cell, on both sides of which are attached a PI heating film elastic system assembly as described above. Two PI heating film elastic system assemblies are connected in series at the same end through a conductive film to form a circuit, and the other ends are respectively connected to wires, with terminals provided at the ends of the wires.

[0014] By adopting the above technical solution, this utility model has the following beneficial effects:

[0015] (1) This utility model changes the design of the existing structure where the deformation section extends along the width direction to both sides of the insulating film. By shortening the length of the deformation section, the internal stress generated during the deformation process is relatively small. It can more effectively utilize the elasticity and memory effect of the material itself and the smaller external force to restore the original shape, making it easier to restore the original shape when retracting. It avoids causing secondary bending to the resistance wire attached to the deformation section. Furthermore, the adjacent deformation sections are located at the upper and lower ends of the insulating film, which can better balance the deformation of the entire heating film along the length direction.

[0016] (2) By setting a strip-shaped through groove, the present invention allows for fewer connections between each layout area of ​​the insulating film. When the heating film is stretched and deformed, it gains a certain degree of freedom, thus avoiding interference with the deformation of the deformed section.

[0017] (3) By setting a notch, the present invention forms a weak connection point. When the body of the insulating film is stretched to a certain extent, the weak connection point breaks first, avoiding pulling on the resistance wires on both sides. At the same time, due to the existence of the weak connection point, the insulating film can still maintain a relatively complete rectangular structure, which is convenient to adhere to the battery cell.

[0018] (4) The notch of this utility model is set as an arc-shaped notch, and the corresponding strip groove is also set as an arc-shaped structure. This can realize the weak connection point that is easy to break. At the same time, under normal circumstances, the weak connection point is not easy to break, thus avoiding the weak connection point being pulled and broken when the insulating film is adhered to the battery cell, which would result in the battery cell surface not being well adhered.

[0019] (5) By setting the resistance wire in the deployment area into an S-shaped structure and setting it longitudinally, the resistance wire in this area has the same degree of freedom as the stretching direction of the insulating film, thus further avoiding the risk of resistance wire breakage.

[0020] (6) This utility model achieves a smaller resistance and less heat generation by setting the resistance wire of the deformed section to a larger cross-sectional area, thus avoiding local overheating, energy waste and thermal stress concentration. Attached Figure Description

[0021] To make the content of this utility model easier to understand, the present utility model will be further described in detail below with reference to specific embodiments and accompanying drawings, wherein:

[0022] Figure 1 This is a schematic diagram of the PI heating film elastic system assembly of this utility model;

[0023] Figure 2 This is a partial structural schematic diagram of the PI heating film elastic system assembly of this utility model;

[0024] Figure 3 This is a schematic diagram of the structure of the insulating film of this utility model;

[0025] Figure 4 This is a schematic diagram of the resistance wire structure of this utility model;

[0026] Figure 5 This is a schematic diagram of the combined state of the insulating film and the resistance wire of this utility model.

[0027] The labels in the attached diagram are:

[0028] Conductive film 100, wire 200, terminal block 300;

[0029] Insulating film 1, arched buffer strip 1-1, strip groove 1-2, notch 1-3, weak connection point 1-4, adhesive backing layer 2, resistance wire 3. Detailed Implementation

[0030] To better understand the above technical solutions, the following will provide a detailed explanation of the technical solutions in conjunction with the accompanying drawings and specific implementation methods.

[0031] (Example 1)

[0032] This embodiment provides a battery pack, including a battery cell and a PI heating film elastic system assembly adhered to both sides of the battery cell, such as... Figures 1 to 5 As shown, the two PI heating film elastic system assemblies are connected in series at the same end via a conductive film 100 to form a circuit, and the other ends are respectively connected to wires 200, with terminals 300 at the ends of the wires 200. By optimizing the structure of the PI heating film elastic system assembly, it can better follow the changes when the battery cell expands and deforms, thereby achieving a longer actual service life and higher utilization rate.

[0033] Specifically, the conductor 200 uses high-temperature resistant silicone insulation material and copper core conductor, and is connected to the resistance wire by crimping and soldering. It is combined with the quick-connect single-core terminal block 300 to achieve minimum contact resistance.

[0034] The PI heating film elastic system assembly includes an insulating film 1 disposed opposite to the battery cell. The outer side of the insulating film 1, which is close to the battery cell, is provided with an adhesive layer 2. The adhesive layer 2 is made of highly viscous acrylic acid, which can prevent peeling under long-term high temperature conditions of 145°C, ensuring good contact tightness and thus achieving maximum heat conduction efficiency.

[0035] A resistance wire 3 is provided between two insulating films 1. The top and bottom of the insulating film 1 are alternately provided with arched buffer strips 1-1 protruding towards the side away from the adhesive layer 2, forming deformation sections. These vertically distributed deformation sections divide the insulating film 1 into multiple layout areas. The resistance wire 3 located in each layout area forms a heating section, which is connected in series to provide heat when energized. Simultaneously, the resistance wires used for connecting the heating sections are located in the corresponding deformation sections and conform to the cross-sectional shape of the deformation sections, thus allowing for a margin on the resistance wire 3 to expand and contract synchronously with the deformation sections. The deformation sections extend along the width direction of the insulating film 1, and a gap is provided between adjacent deformation sections along the width direction of the insulating film 1. The length of the gap is preferably the same as the length of the deformation section, ensuring sufficient deformation of the insulating film while avoiding excessively long deformation sections that would affect retraction and recovery.

[0036] The insulating film 1 has strip-shaped grooves 1-2 aligned with the deformation section, resulting in fewer connections between each area of ​​the insulating film 1. This allows the heating film to have a certain degree of freedom when stretched and deformed, avoiding interference with the deformation of the deformation section. A notch 1-3 is provided on the side of the strip-shaped groove 1-2 away from the deformation section, aligned with the edge of the insulating film 1. The notch 1-3 is aligned with the strip-shaped groove 1-2, forming a weak connection point 1-4 between the notch 1-3 and the strip-shaped groove 1-2. When the insulating film 1 is stretched to a certain extent, the weak connection point 1-4 breaks first, preventing pulling on the resistance wires 3 on both sides. Furthermore, due to the presence of the weak connection point 1-4, compared to the connection at the edge of the insulating film 1 where the strip-shaped groove 1-2 extends, the insulating film 1 maintains a relatively complete rectangular structure, making it easier to adhere to the battery cell. To prevent the notch 1-3 from being accidentally torn during the application of the insulating film 1, this embodiment designs the notch 1-3 as an arc-shaped gap, and the end of the strip groove 1-2 near the notch 1-3 is also designed as an arc-shaped structure. This not only achieves the weak connection point 1-4 which is prone to breakage, but also ensures that the weak connection point 1-4 is not easily broken under normal conditions.

[0037] To further prevent the resistance wire 3 from breaking, this embodiment designs the resistance wire 3 in the deployment area as a continuous S-shaped distribution arranged longitudinally. This allows the resistance wire 3 in this area to have the same degree of freedom as the stretching direction of the insulating film 1, further avoiding the risk of the resistance wire 3 breaking. At the same time, the cross-sectional area of ​​the resistance wire 3 in the deformed section is larger than that of the resistance wire 3 located in the deployment area, giving it higher strength, making it less prone to breakage, and increasing its resilience. In addition, this allows the resistance wire 3 in the deformed section to achieve lower resistance, resulting in less heat generation and avoiding local overheating, energy waste, and thermal stress concentration.

[0038] This invention changes the design of the existing structure where the deformable section extends along the width direction to both sides of the insulating film. By shortening the length of the deformable section, the internal stress generated during deformation is relatively small. It can more effectively utilize the elasticity and memory effect of the material itself and restore the original shape with less external force, making it easier to restore the original shape when retracting. This avoids secondary bending of the resistance wire attached to the deformable section. Furthermore, the adjacent deformable sections are located at the upper and lower ends of the insulating film, which can better balance the deformation of the entire heating film along the length direction.

[0039] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of this utility model. It should be understood that the above descriptions are merely specific embodiments of this utility model and are not intended to limit this utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A PI heating film elastic system assembly, comprising insulating films disposed opposite each other, an adhesive backing layer disposed on the outer side of any one of the insulating films, and a resistance wire disposed between the two insulating films, characterized in that: The top and bottom of the insulating film are alternately provided with deformable sections along the length direction. The deformable sections divide the insulating film into multiple layout areas. The resistance wires located in the layout areas form heating parts. The heating parts are arranged in series, and the resistance wires used for the series heating parts are located in the corresponding deformable sections and fit the cross-sectional shape of the deformable sections. The deformable sections extend along the width direction of the insulating film, and there is a gap between two adjacent deformable sections along the width direction of the insulating film.

2. The PI heating film elastic system assembly according to claim 1, characterized in that: The deformable section is an arched buffer strip that bulges out toward the side away from the adhesive backing layer.

3. The PI heating film elastic system assembly according to claim 1, characterized in that: The insulating film has a strip-shaped through-slot aligned with the deformed section.

4. The PI heating film elastic system assembly according to claim 3, characterized in that: The strip groove has a notch on the edge of the insulating film on the side away from the deformed section. The notch is aligned with the strip groove, thus forming a weak connection point between the notch and the strip groove.

5. The PI heating film elastic system assembly according to claim 4, characterized in that: The notch is an arc-shaped opening, and the end of the strip-shaped through groove near the notch is also an arc-shaped structure.

6. The PI heating film elastic system assembly according to claim 1, characterized in that: The resistance wires located in the deployment area are arranged in a continuous S-shape along the longitudinal direction.

7. The PI heating film elastic system assembly according to claim 1, characterized in that: The cross-sectional area of ​​the resistance wire located in the deformation section is larger than that of the resistance wire located in the deployment area.

8. A battery pack, characterized in that: The battery cell has a PI heating film elastic system assembly as described in any one of claims 1 to 7 adhered to both sides of the battery cell. The same end of two PI heating film elastic system assemblies is connected in series through a conductive film to form a circuit, and the other end is connected to a wire, the end of which is provided with a terminal.

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