Heated film and battery module

Abstract

The application relates to the battery technical field and discloses a heating film and a battery module. The heating film comprises a plurality of main body parts, a plurality of weak parts and a plurality of connecting parts. The plurality of main body parts are arranged at intervals along a first direction, the first direction intersects the thickness direction of the heating film, and the main body part comprises a heating device. The plurality of weak parts and the plurality of main body parts are alternately arranged along the first direction, two adjacent main body parts are connected through the weak part, the strength of the weak part is less than that of the main body part. The connecting part comprises a conductive device, the heating devices of two adjacent main body parts are electrically connected through the conductive device of the connecting part, and the connecting part is configured to be able to be deformed under external force. When the connecting part is in an unfolded state, the interval of two adjacent main body parts in the first direction is a first interval, and when the connecting part is in a contracted state, the interval of two adjacent main body parts in the first direction is a second interval, and the first interval is greater than the second interval.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, specifically to a heating film and a battery module. Background Technology

[0002] With the development of new energy vehicles and energy storage technologies, power battery technology is also constantly advancing. The application of power battery systems in the automotive field is becoming increasingly widespread. A lithium-ion battery pack consists of multiple lithium-ion battery cells connected together in a series-parallel structure, providing the required voltage, current, and charge to the output system. Lithium-ion battery cells store or release electricity through chemical reactions. As is well known, temperature has a significant impact on chemical reactions, especially when the battery is in a low-temperature environment, where charging efficiency is very low. To meet the requirements for battery operation at low temperatures, safe, reliable, and efficient battery heating devices are needed.

[0003] Currently, the most common heating method is heating film heating. Heating film is a thin film that generates heat. It is directly attached to the surface of each battery cell in the battery module with double-sided adhesive. The heat generated by internal electricity is directly transferred to the battery, resulting in high heating efficiency.

[0004] However, conventional heating films are integral heating films, directly adhered to the surface of the battery cells. During charging and discharging, the battery cells expand, causing them to deform and shift. This deformation and shift can stretch the heating film, potentially leading to breakage and failure, thus affecting its heating function. Utility Model Content

[0005] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes a heating film and battery module that can reduce the probability of heating film failure.

[0006] According to a first aspect of the present invention, a heating film includes multiple main bodies, multiple weak parts, and multiple connecting parts. The multiple main bodies are arranged at intervals along a first direction, which intersects the thickness direction of the heating film. Each main body includes a heating device. The multiple weak parts and the multiple main bodies are alternately arranged along the first direction. Adjacent main bodies are connected by weak parts, and the strength of the weak parts is less than the strength of the main bodies. Each connecting part includes a conductive device. The heating devices of adjacent main bodies are electrically connected through the conductive device of the connecting part, and the connecting part is configured to deform under external force. The connecting part has an expanded state and a contracted state. When the connecting part is in the expanded state, the distance between two adjacent main bodies in the first direction is a first distance. When the connecting part is in the contracted state, the distance between two adjacent main bodies in the first direction is a second distance, and the first distance is greater than the second distance. When the connecting part is in the contracted state, at least a portion of the connecting part extends along the thickness direction of the heating film.

[0007] The heating film according to the first aspect of this utility model has at least the following beneficial effects: By including a plurality of main body portions and a plurality of weak portions alternately arranged along a first direction, and making the strength of the weak portions less than the strength of the main body portions, the weak portions of the heating film can preferentially deform when stretched by a battery cell, which reduces the risk of deformation failure of the main body portions and allows the heating film to be stretched to adapt to the expansion displacement of the battery cells. By including a plurality of connecting portions of the heating film, and making the heating devices of two adjacent main body portions electrically connected through the conductive devices of the connecting portions, the circuit on the heating film remains conductive even when the weak portions deform or even break, thereby improving the stability of the heating film and reducing the probability of failure. By configuring the connecting portions to deform under external force, and making the connecting portions have an expanded state and a contracted state, the connecting portions of the heating film can adaptively deform when stretched by a battery cell, reducing the risk of breakage of the connecting portions and thus reducing the probability of failure of the heating film. By having at least a portion of the connecting part extend along the thickness direction of the heating film when the connecting part is in a contracted state, it is easy to house the connecting part on the side of the battery cell, thereby reducing the probability of heating film failure and minimizing the impact of the heating film on volume.

[0008] According to some embodiments of the present invention, the weak part includes a weak groove extending along a second direction, wherein the second direction, the first direction, and the thickness direction of the heating film are arranged to intersect each other.

[0009] According to some embodiments of the present invention, the length of the weak groove in the second direction is less than the length of the main body in the second direction.

[0010] According to some embodiments of the present invention, the weak portion further includes a first notch, which is located on at least one side of the weak groove in the second direction, and the first notch is connected to the weak groove.

[0011] According to some embodiments of the present invention, the first notch includes a first end facing the weak groove and a second end away from the weak groove, the weak groove being connected to the first end; along the direction from the second end to the first end, the size of the first notch gradually decreases in the first direction.

[0012] According to some embodiments of the present invention, the connecting portion is located on at least one side of the weak portion in the second direction, and the second direction, the first direction and the thickness direction of the heating film are arranged to intersect each other.

[0013] According to some embodiments of the present invention, the weak part is provided with connecting parts on both sides in the second direction, and adjacent main parts are connected by the connecting parts on both sides.

[0014] According to some embodiments of the present invention, a second notch is provided on the main body, and the connecting part is connected to the wall of the second notch; in the thickness direction of the heating film, the orthographic projection of the second notch and the orthographic projection of the connecting part at least partially overlap.

[0015] According to some embodiments of the present invention, the connecting portion is located on at least one side of the main body portion in the second direction.

[0016] According to some embodiments of the present invention, the connecting part includes a first segment, a second segment, and an intermediate segment. The first segment and the second segment are connected through the intermediate segment, and the first segment and the second segment are respectively connected to two adjacent main body parts. When the connecting part is in a contracted state, the first segment and / or the second segment extend along the thickness direction of the heating film.

[0017] According to some embodiments of this utility model, the strength of the connecting part is greater than the strength of the weak part.

[0018] According to some embodiments of this utility model, the weak portion is configured to deform under external force; when the connecting portion is in the unfolded state, the length of the weak portion in the first direction is a first length.

[0019] When the connecting part is in a contracted state, the length of the weak part in the first direction is the second length, and the first length is greater than the second length.

[0020] According to some embodiments of the present invention, the cross-sectional shape of the weak part in the cross section perpendicular to the second direction is wavy, and the second direction, the first direction and the thickness direction of the heating film are arranged to intersect each other.

[0021] A battery module according to a second aspect of the present invention includes a plurality of battery cells and a heating film as described in any of the first aspects of the present invention. The plurality of battery cells are arranged along a first direction, the heating film is connected to the surface of the battery cells, and a plurality of main bodies are aligned with the plurality of battery cells one to one.

[0022] The heating film according to the second aspect of this utility model has at least the following beneficial effects: By including a plurality of main body portions and a plurality of weak portions alternately arranged along a first direction, and making the strength of the weak portions less than the strength of the main body portions, the weak portions of the heating film can preferentially deform when stretched by a battery cell, which reduces the risk of deformation failure of the main body portions and allows the heating film to be stretched to adapt to the expansion displacement of the battery cells. By including a plurality of connecting portions of the heating film, and making the heating devices of two adjacent main body portions electrically connected through the conductive devices of the connecting portions, the circuit on the heating film remains conductive even when the weak portions deform or even break, thereby improving the stability of the heating film and reducing the probability of failure. By configuring the connecting portions to be deformable under external force, and making the connecting portions have an expanded state and a contracted state, the connecting portions of the heating film can adaptively deform when stretched by a battery cell, reducing the risk of breakage of the connecting portions and thus reducing the probability of failure of the heating film. By having at least a portion of the connecting part extend along the thickness direction of the heating film when the connecting part is in a contracted state, it is easy to house the connecting part on the side of the battery cell, thereby reducing the probability of heating film failure and minimizing the impact of the heating film on volume.

[0023] According to some embodiments of the present invention, in the contracted state, at least a portion of the connecting portion is located on one side of the battery cell in the second direction, and the second direction, the first direction and the thickness direction of the heating film are arranged to intersect each other.

[0024] According to some embodiments of the present invention, the maximum dimension of the heating film in the second direction is greater than the maximum dimension of the battery cell in the second direction.

[0025] According to some embodiments of the present invention, a battery cell includes a casing and a cell at least partially covered by the casing, and the casing has a third notch for exposing the cell; the battery module also includes thermally conductive adhesive, at least a portion of which is located within the third notch, and the thermally conductive adhesive connects the cell and the main body.

[0026] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0027] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0028] Figure 1 This is a side view of the heating film in the contracted state according to an embodiment of this application.

[0029] Figure 2 This is a side view of the heating film in the unfolded state according to an embodiment of this application.

[0030] Figure 3 for Figure 1 A top view of the heating film in the middle;

[0031] Figure 4 for Figure 2 A top view of the heating film in the middle;

[0032] Figure 5 This is a top view of the heating film according to another embodiment of this application;

[0033] Figure 6 This is a top view of the heating film according to another embodiment of this application;

[0034] Figure 7 This application also provides a top view of the heating film according to an embodiment;

[0035] Figure 8 This application also provides a top view of the heating film according to an embodiment;

[0036] Figure 9 This application also provides a top view of the heating film according to an embodiment;

[0037] Figure 10 This application also provides a top view of the heating film according to an embodiment;

[0038] Figure 11 This is a partial side view of the heating film structure of this application;

[0039] Figure 12 This is a partial cross-sectional schematic diagram of the heating film of this application;

[0040] Figure 13 This is a side view of the battery module of this application after the hidden portion structure is shown.

[0041] Figure 14 This is a partial side view of the battery module of this application after the hidden part of the structure is shown.

[0042] Figure label:

[0043] 10. Heating film; 11. First side; 12. Second side; 20. Battery cell; 21. Casing; 22. Cell; 23. Third notch; 30. Fixed end plate; 40. Movable end plate; 50. Elastic element; 60. Thermally conductive adhesive;

[0044] 100. Main body; 110. Second gap;

[0045] 200. Weak point; 210. Weak groove; 220. First notch; 221. First end; 222. Second end;

[0046] 300. Connecting section; 310. First section; 320. Second section; 330. Middle section;

[0047] x, first direction; y, second direction; z, thickness direction of the heating film. Detailed Implementation

[0048] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0049] In the description of this application, it should be understood that if terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" appear, these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, 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, and therefore should not be construed as a limitation of this application.

[0050] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, the term "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0051] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," "fixing," etc., shall be interpreted broadly. For example, they may refer to a fixed connection, a detachable connection, or an integral part; a mechanical connection or an electrical connection; a direct connection or an indirect connection through an intermediate medium; or the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0052] In this application, unless otherwise expressly specified and limited, the use of descriptions such as "above" or "below" the second feature indicates that the first and second features are in direct contact or indirect contact via an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. Similarly, "below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0053] It should be noted that if an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. If an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. If so, the terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this application are for illustrative purposes only and do not represent the only possible implementation.

[0054] The heating film provided in the embodiments of this application will be described below with reference to the accompanying drawings. It should be noted that in the drawings, the x-direction is the first direction, the y-direction is the second direction, and the z-direction is the thickness direction of the heating film. In the drawings, for ease of drawing, the dimensions are not necessarily proportional to the actual dimensions.

[0055] Please refer to Figures 1 to 4 , Figure 1 This is a side view of the heating film in the contracted state according to an embodiment of this application. Figure 2 This is a side view of the heating film in the unfolded state according to an embodiment of this application. Figure 3 for Figure 1 A top view of the heating film in the middle; Figure 4 for Figure 2 A top view of the heating film.

[0056] like Figures 1 to 4As shown, this application provides a heating film 10, including multiple main bodies 100, multiple weak points 200, and multiple connecting parts 300. The multiple main bodies 100 are arranged at intervals along a first direction (x direction in the figure), and the first direction x intersects the thickness direction of the heating film 10 (z direction in the figure). Each main body 100 includes a heating device (not shown). The multiple weak points 200 and the multiple main bodies 100 are alternately arranged along the first direction x, and adjacent two main bodies 100 are connected by weak points 200. The strength of the weak points 200 is less than the strength of the main bodies 100. Each connecting part 300 includes a conductive device (not shown), and the heating devices of adjacent two main bodies 100 are electrically connected through the conductive device of the connecting part 300. The connecting part 300 is configured to deform under external force. The connecting part 300 has an expanded state and a contracted state. When the connecting part 300 is in the expanded state, the distance between adjacent two main bodies 100 in the first direction x is a first distance (…). Figure 2 , 4 In the dimension L1), when the connecting part 300 is in the retracted state, the distance between two adjacent main body parts 100 in the first direction x is the second distance ( Figure 1 , 3 The first spacing L1 is greater than the second spacing L2. And when the connecting portion 300 is in the contracted state, at least a portion of the connecting portion 300 extends along the thickness direction z of the heating film 10.

[0057] Optionally, the heating element can be a resistance wire, which generates heat and heats the battery cells when energized. The conductive element can be a resistance wire or a regular wire. Both the main body 100 and the connecting part 300 include an insulating film, which is used to cover the heating element and the conductive element to reduce the risk of short circuits.

[0058] Optionally, the statement that the strength of the weak portion 200 is less than the strength of the main body 100 means that the strength of the weak portion 200 itself is less than the strength of the main body 100 itself. When the heating film 10 is subjected to external force, due to the lower strength of the weak portion 200, the weak portion 200 will deform first than the main body 100. The deformation of the weak portion 200 can be elastic deformation, brittle deformation, or both. When the weak portion 200 deforms elastically, it will be elongated under external force, thereby increasing the distance between adjacent main body portions 100. When the weak portion 200 deforms brittlely, it will be torn under external force, and adjacent main body portions 100, losing the constraint of the weak portion 200, will move away from each other under external force, similarly increasing the distance between adjacent main body portions 100. In this embodiment, the deformation of the weak portion 200 as brittle deformation is used as an example for explanation.

[0059] Optionally, the strength difference between the weak portion 200 and the main body 100 can be achieved through methods such as material, size, and processing technology. For example, the weak portion 200 can be made of a more elastic material, making it more prone to elastic deformation when subjected to external force. Alternatively, the thickness of the weak portion 200 can be thinner than that of the main body 100, making it more easily torn when subjected to external force.

[0060] It should be noted that in the specific application scenario of the heating film 10, the heating film 10 is connected to the battery cell, and each main body 100 is respectively attached to the surface of a different battery cell. When the battery cell does not expand and shift, the connecting part 300 is in a contracted state. When the battery cell heats up and expands during charging and discharging, adjacent battery cells will squeeze each other and cause displacement. Since each main body 100 is attached to a different battery cell, each main body 100 will move with the displacement of the battery cell, increasing the distance between adjacent main bodies 100. At this time, the connecting part 300 changes from a contracted state to an expanded state. When the charging and discharging of the battery cell stops, the battery cell may retract and drive the main body 100 to move, causing the connecting part 300 to change from an expanded state back to a contracted state. In this scenario, the contracted and expanded states of the connecting part 300 can be switched between each other. However, if the expansion of the battery cell is irreversible, and the battery cell does not retract even after charging and discharging stops, then the connecting part 300 can only change from a contracted state to an expanded state, and cannot change from an expanded state back to a contracted state.

[0061] Optionally, the strength of the connecting portion 300 is greater than that of the weak portion 200, so that the weak portion 200 can deform preferentially when the heating film 10 is pulled by the battery cell, thereby improving the connection stability of the connecting portion 300. Even if the weak portion 200 breaks, the circuit on the heating film 10 will still be conductive due to the presence of the connecting portion 300, thereby improving the stability of the heating film 10 and reducing the failure probability of the heating film 10.

[0062] The heating film 10 provided in this application includes multiple main body portions 100 and multiple weak portions 200 alternately arranged along a first direction x, and the strength of the weak portions 200 is less than the strength of the main body portions 100. This allows the weak portions 200 to deform preferentially when the heating film 10 is stretched by a battery cell, reducing the risk of deformation and failure of the main body portions 100 and allowing the heating film 10 to be stretched to accommodate the expansion displacement of the battery cell. By including multiple connecting portions 300 and electrically connecting the heating devices of two adjacent main body portions 100 through conductive devices in the connecting portions 300, the circuit on the heating film 10 remains conductive even when the weak portions 200 deform or even break, thereby improving the stability of the heating film 10 and reducing the probability of failure. By configuring the connecting portion 300 to deform under external force and having both an expanded and a contracted state, the connecting portion 300 can adaptively deform when the heating film 10 is stretched by the battery cell, reducing the risk of breakage and thus lowering the probability of failure of the heating film 10. When the connecting portion 300 is in the contracted state, at least a portion of it extends along the thickness direction z of the heating film 10, facilitating its placement on the side of the battery cell. This reduces the probability of failure of the heating film 10 while minimizing its impact on volume.

[0063] In some embodiments, the weak portion 200 includes a weak groove 210 extending along a second direction (y direction in the figure), wherein the second direction y, the first direction x, and the thickness direction z of the heating film 10 are arranged to intersect each other.

[0064] Optionally, the weak groove 210 is a dotted-line groove. The weak groove 210 is formed by machining a dotted-line groove in the weak part 200 area, so that the strength of the weak groove 210 is lower than that of the main body 100. When the heating film 10 is subjected to external force, the heating film 10 is more likely to deform and break at the weak groove 210, thereby realizing the function of increasing the distance between adjacent main body parts 100.

[0065] Optionally, the weak groove 210 is a thinning groove, which can be understood as the thickness of the weak groove 210 being smaller than the thickness of the main body 100, making the strength of the weak groove 210 lower than the strength of the main body 100. When the heating film 10 is subjected to external force, the heating film 10 is more likely to deform and break at the weak groove 210, thereby realizing the function of increasing the distance between adjacent main body parts 100.

[0066] The heating film 10 provided in this application includes a weak groove 210 extending along the second direction y in the weak portion 200, so that the strength of the weak portion 200 is lower than that of the main body portion 100. This causes the weak portion 200 to deform when the heating film 10 is subjected to external force, thereby increasing the distance between adjacent main body portions 100.

[0067] Please refer to Figure 3 and Figure 5 This is a top view of the heating film according to another embodiment of this application.

[0068] In some embodiments, the length of the weak groove 210 in the second direction y ( Figure 3 The dimension L3 in the middle is smaller than the length of the main body 100 in the second direction y ( Figure 3 (Dimension L4 in the middle).

[0069] Optionally, the length of the weak groove 210 in the second direction y is greater than half the length of the main body portion 100 in the second direction y. By making the length of the weak groove 210 in the second direction y greater than half the length of the main body portion 100 in the second direction y, after the weak groove 210 is torn, the tear is more likely to continue to break along the extension direction of the weak groove 210, thereby making it possible for adjacent main body portions 100 to be connected only by the connecting portion 300.

[0070] The heating film 10 has a first side 11 and a second side 12 disposed opposite to each other along the second direction y.

[0071] Optionally, the weak groove 210 has a certain distance between its two ends in the second direction y and the first side 11 and the second side 12.

[0072] Optional, such as Figure 3 As shown, the weak groove 210 is connected to the first side 11, and there is a certain distance between the weak groove 210 and the second side 12.

[0073] Optional, such as Figure 5 As shown, a portion of the weak groove 210 is connected to the first side 11, and a portion of the connecting part 300 is located on the side of the weak groove 210 facing the second side 12. Another portion of the weak groove 210 is connected to the second side 12, and a portion of the connecting part 300 is located on the side of the weak groove 210 facing the first side 11.

[0074] Please refer to Figure 3 , Figure 6 and Figure 7 , Figure 6 This is a top view of the heating film according to another embodiment of this application; Figure 7 This is a top view of the heating film according to another embodiment of the present application.

[0075] In some embodiments, the connecting portion 300 is located on at least one side of the weak portion 200 in the second direction y, and the second direction y, the first direction x and the thickness direction z of the heating film 10 are arranged to intersect each other.

[0076] Optional, such as Figure 3As shown, the main body 100 has a second notch 110, and the connecting portion 300 is connected to the wall surface of the second notch 110. In the thickness direction z of the heating film 10, the orthographic projection of the second notch 110 at least partially overlaps with the orthographic projection of the connecting portion 300. By providing the second notch 110 on the main body 100, the second notch 110 is used to accommodate the connecting portion 300, thereby reducing the impact of the connecting portion 300 on the overall size of the heating film 10.

[0077] Optional, such as Figure 6 As shown, the connecting portion 300 is located on at least one side of the main body portion 100 in the second direction y.

[0078] Optional, such as Figure 7 As shown, the weak portion 200 has connecting portions 300 on both sides in the second direction y, and adjacent main body portions 100 are connected by the connecting portions 300 on both sides. By providing connecting portions 300 on both sides of the weak portion 200 in the second direction y, the connection stability between adjacent main body portions 100 is improved.

[0079] Please refer to Figures 8 to 10 , Figure 8 This application also provides a top view of the heating film according to an embodiment; Figure 9 This application also provides a top view of the heating film according to an embodiment; Figure 10 This is a top view of the heating film according to another embodiment of the present application.

[0080] In some embodiments, the weak portion 200 further includes a first notch 220 located on at least one side of the weak groove 210 in the second direction y, and the first notch 220 is connected to the weak groove 210.

[0081] Optionally, the first notch 220 includes a first end 221 facing the weak groove 210 and a second end 222 facing away from the weak groove 210, the weak groove 210 being connected to the first end 221. Along the direction from the second end 222 to the first end 221, the size of the first notch 220 gradually decreases in the first direction x.

[0082] Optionally, the first notch 220 can be U-shaped, V-shaped, or semi-circular.

[0083] Optional, such as Figure 8 As shown, the first notch 220 is located on the same side of the weak groove 210 in the second direction y.

[0084] Optional, such as Figure 9 As shown, the weak groove 210 has a first notch 220 on both sides in the second direction y.

[0085] Optional, such as Figure 10As shown, a portion of the weak groove 210 is connected to the first side 11, and the first notch 220 is located on the side of the weak groove 210 facing the second side 12. Another portion of the weak groove 210 is connected to the second side 12, and the first notch 220 is located on the side of the weak groove 210 facing the first side 11.

[0086] The heating film 10 provided in this application further includes a first notch 220 in the weak portion 200. The first notch 220 is located on at least one side of the weak groove 210 in the second direction y and is connected to the weak groove 210. The size of the first notch 220 gradually decreases in the first direction x along the direction from the second end 222 to the first end 221. This allows the heating film 10 to be guided to tear along the weak groove 210 when it is subjected to external force, reducing the risk of random tear extension and thus reducing the risk of the main body 100 being torn, further reducing the probability of failure of the heating film.

[0087] Please refer to Figure 11 , Figure 11 This is a partial side view of the heating film structure of this application. Wherein, Figure 11 The connecting part 300 is in a retracted state.

[0088] like Figure 11 As shown, in some embodiments, the connecting portion 300 includes a first segment 310, a second segment 320, and an intermediate segment 330. The first segment 310 and the second segment 320 are connected through the intermediate segment 330, and the first segment 310 and the second segment 320 are respectively connected to two adjacent main body portions 100. When the connecting portion 300 is in a retracted state, the first segment 310 and / or the second segment 320 extend along the thickness direction z of the heating film 10.

[0089] Optionally, when the connecting portion 300 is in the retracted state, the connecting portion 300 is approximately U-shaped or V-shaped.

[0090] It is easy to understand that when the connecting part 300 is in a contracted state, the connecting part 300 is approximately U-shaped or V-shaped. When the distance between adjacent main body parts 100 increases, the dimension of the connecting part 300 in the first direction x has a certain margin. The connecting part 300 can be straightened and continue to maintain the connection relationship between adjacent main body parts 100. This allows the connecting part 300 to deform adaptively when the heating film 10 is pulled by the battery cell, reducing the risk of breakage of the connecting part 300 and thus reducing the failure probability of the heating film 10.

[0091] Please refer to Figure 12 , Figure 12 This is a partial cross-sectional schematic diagram of the heating film of this application.

[0092] In some embodiments, the weak portion 200 is configured to deform under external force. When the connecting portion 300 is in the extended state, the length of the weak portion 200 in the first direction x is a first length, and when the connecting portion 300 is in the retracted state, the length of the weak portion 200 in the first direction x is a second length, wherein the first length is greater than the second length.

[0093] When the weak portion 200 deforms into an elastic form, it will elongate under external force, thereby increasing the distance between adjacent main portions 100. The stretchability of the weak portion 200 can be achieved through either its material or its shape. For example, the material of the weak portion 200 can be highly elastic plastic, rubber, or it can be a spring.

[0094] Optional, such as Figure 12 As shown, the cross-sectional shape of the weak portion 200 in the cross-section perpendicular to the second direction y is wavy. By making the weak portion 200 wavy, the tensile properties of the weak portion 200 are improved, thereby enabling each main body 100 to move with the displacement of the battery cell.

[0095] In other embodiments, the cross-sectional shape of the weak portion 200 may also be V-shaped, U-shaped, S-shaped, W-shaped, etc.

[0096] Please refer to Figure 13 , Figure 13 This is a side view of the battery module of this application after the hidden part of the structure is shown.

[0097] like Figure 13 As shown, an embodiment of the second aspect of this application provides a battery module including a plurality of battery cells 20 and a heating film 10 as described in any of the first aspects of the embodiment above. The plurality of battery cells 20 are arranged along a first direction x, the heating film 10 is connected to the surface of the battery cells 20, and a plurality of main body portions 100 are arranged in a one-to-one correspondence with the plurality of battery cells 20.

[0098] Optionally, the battery cell 20 is a square battery cell with six surfaces. When multiple battery cells 20 are arranged along the first direction x, the heating film 10 is located above the battery cells 20, and the upper surface of each battery cell 20 is respectively adhered to multiple main body portions 100. In the contracted state, at least a portion of the connecting portion 300 is located on one side of the battery cell 20 in the second direction y.

[0099] Optionally, the maximum dimension of the heating film 10 in the second direction y is greater than the maximum dimension of the battery cell 20 in the second direction y.

[0100] The battery module provided in this application increases the heating area of ​​the heating film 10 on the battery cell 20 by making the heating film 10 slightly wider than the battery cell 20 in the second direction y, while making it easier to house the connecting part 300 on the side of the battery cell 20. This reduces the probability of failure of the heating film 10 and reduces the impact of the heating film 10 on the volume.

[0101] In some embodiments, the battery module further includes a base plate (not shown), two fixed end plates 30, and a movable end plate 40, with all battery cells 20 located on the same side of the base plate. The fixed end plates 30 are fixedly connected to the base plate, and the two fixed end plates 30 are located on opposite sides of the battery cells 20 in a first direction x. The movable end plate 40 is located between the two fixed end plates 30, and the two outermost battery cells 20 in the first direction x are connected to the movable end plate 40 and one of the fixed end plates 30, respectively. The movable end plate 40 is configured to be movable along the first direction x.

[0102] Optionally, the battery module also includes an elastic element 50, which is located on the side of the movable end plate 40 away from the battery cell 20. One end of the elastic element 50 abuts against the movable end plate 40, and the other end abuts against the fixed end plate 30. The elastic element 50 is used to apply a force close to the battery cell 20 to the movable end plate 40.

[0103] Optionally, the main body 100 is located on the side of the battery cell 20 away from the bottom plate.

[0104] The battery module provided in this application, by setting a movable end plate 40 and making the movable end plate 40 movable along the first direction x, allows the movable end plate 40 to be pushed by the battery cell 20 when it expands, thereby releasing the stress of the battery cell 20 and reducing the probability of damage to the battery cell 20. By setting an elastic element 50 between the movable end plate 40 and the fixed end plate 30, the elastic element 50 is used to ensure that the battery cells 20 are tightly fitted, which is conducive to uniform heat conduction, reduces local overheating, and makes the stress and temperature distribution of the entire battery module more consistent, thus extending the cycle life of the battery cells 20.

[0105] Please refer to Figure 14 , Figure 14 This is a partial side view of the battery module of this application after the hidden part of the structure is shown.

[0106] like Figure 14 As shown, in some embodiments, the battery cell 20 includes a housing 21 and a cell 22 at least partially covered by the housing 21. The housing 21 has a third notch 23 for exposing the cell 22. The battery module also includes thermally conductive adhesive 60, at least partially located within the third notch 23, and the thermally conductive adhesive 60 connects the cell 22 and the main body 100.

[0107] The outer casing 21 can be made of steel, aluminum, plastic (such as polypropylene), composite metal (such as copper-aluminum composite casing), or aluminum-plastic film, etc. The outer casing 21 serves to protect the battery cell 22.

[0108] In this embodiment, the third notches 23 are all located on the side of the cell 22 facing the heating film 10. By filling the third notches 23 with thermally conductive adhesive 60 and connecting the cell 22 and the main body 100 with the thermally conductive adhesive 60, the heating film 10 can directly heat the cell 22 through the thermally conductive adhesive 60, reducing the influence of the outer shell 21 on heat transfer, thereby improving the heating effect of the heating film 10 on the battery cell 20.

[0109] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this application.

[0110] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A heating film for heating a single battery cell, characterized in that, include: A plurality of main body portions are arranged at intervals along a first direction, the first direction being intersecting the thickness direction of the heating film, and each main body portion includes a heating device; Multiple weak points are provided, and the multiple weak points and multiple main body parts are alternately arranged along the first direction. Two adjacent main body parts are connected through the weak points, and the strength of the weak points is less than the strength of the main body parts. Multiple connecting portions, each connecting portion including a conductive device, wherein the heating devices of two adjacent main body portions are electrically connected through the conductive device of the connecting portion, and the connecting portion is configured to deform under external force; The connecting portion has an extended state and a retracted state. When the connecting portion is in the extended state, the distance between two adjacent main body portions in the first direction is a first distance. When the connecting portion is in the retracted state, the distance between two adjacent main body portions in the first direction is a second distance. The first distance is greater than the second distance. Furthermore, when the connecting portion is in the retracted state, at least a portion of the connecting portion extends along the thickness direction of the heating film.

2. The heating film according to claim 1, characterized in that, The weak portion includes a weak groove extending along a second direction, wherein the second direction, the first direction, and the thickness direction of the heating film are arranged to intersect each other.

3. The heating film according to claim 2, characterized in that, The length of the weak groove in the second direction is less than the length of the main body in the second direction.

4. The heating film according to claim 3, characterized in that, The weak portion further includes a first notch, which is located on at least one side of the weak groove in the second direction, and the first notch is connected to the weak groove.

5. The heating film according to claim 4, characterized in that, The first notch includes a first end facing the weak groove and a second end away from the weak groove, the weak groove being connected to the first end; the size of the first notch gradually decreases in the first direction along the direction from the second end to the first end.

6. The heating film according to claim 1, characterized in that, The connecting portion is located on at least one side of the weak portion in the second direction, and the second direction, the first direction, and the thickness direction of the heating film are arranged to intersect each other.

7. The heating film according to claim 6, characterized in that, The weak part is provided with the connecting part on both sides in the second direction, and the adjacent main body parts are connected by the connecting parts on both sides.

8. The heating film according to claim 6, characterized in that, The main body is provided with a second notch, and the connecting part is connected to the wall of the second notch; in the thickness direction of the heating film, the orthographic projection of the second notch and the orthographic projection of the connecting part at least partially overlap.

9. The heating film according to claim 6, characterized in that, The connecting portion is located on at least one side of the main body portion in the second direction.

10. The heating film according to claim 1, characterized in that, The connecting part includes a first segment, a second segment, and an intermediate segment. The first segment and the second segment are connected through the intermediate segment. The first segment and the second segment are respectively connected to two adjacent main body parts. When the connecting portion is in the contracted state, the first segment and / or the second segment extend along the thickness direction of the heating film.

11. The heating film according to claim 1, characterized in that, The strength of the connecting part is greater than the strength of the weak part.

12. The heating film according to claim 1, characterized in that, The weak portion is configured to deform under external force; when the connecting portion is in the unfolded state, the length of the weak portion in the first direction is a first length. When the connecting portion is in the contracted state, the length of the weak portion in the first direction is the second length, and the first length is greater than the second length.

13. The heating film according to claim 12, characterized in that, The weak part has a wavy cross-sectional shape on a cross-section perpendicular to the second direction, and the second direction, the first direction, and the thickness direction of the heating film are arranged to intersect each other.

14. A battery module, characterized in that, It includes a plurality of battery cells and a heating film as described in any one of claims 1 to 13, wherein the plurality of battery cells are arranged along a first direction, the heating film is connected to the surface of the battery cells, and the plurality of main body portions are aligned with the plurality of battery cells one to one.

15. The battery module according to claim 14, characterized in that, In the contracted state, at least a portion of the connecting portion is located on one side of the battery cell in the second direction, and the second direction, the first direction, and the thickness direction of the heating film are arranged to intersect each other.

16. The battery module according to claim 15, characterized in that, The maximum dimension of the heating film in the second direction is greater than the maximum dimension of the battery cell in the second direction.

17. The battery module according to claim 14, characterized in that, The battery cell includes a casing and a cell at least partially covered by the casing, wherein the casing has a third notch for exposing the cell; The battery module also includes thermally conductive adhesive, at least a portion of which is located within the third notch, and the thermally conductive adhesive connects the battery cell and the main body.

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