Insulating film, battery cell, and battery

Abstract

This application provides an insulating film, a battery cell, and a battery, including a top cover area, a first side cover area, a first bottom cover area, a second bottom cover area, a second side cover area, and a third side cover area. The top cover area covers the top surface of the winding core; the first side cover area covers both sides of the winding core along its thickness direction; the first bottom cover area covers the bottom surface of the winding core; the second bottom cover area covers the bottom surface of the winding core; the second side cover area extends from the top surface of the winding core to the bottom surface and covers at least a portion of the sides of the winding core extending along its height direction, and at least covers the edge side of the top cover area in the Y direction; the third side cover area extends from the bottom surface to the top surface and covers at least a portion of the sides of the winding core extending along its height direction, and at least covers the edge side of the first bottom cover area in the Y direction. This solves the problem of the winding core being easily broken down by high voltage at its rounded corners, improving battery safety.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, and in particular to an insulating film, a battery cell, and a battery. Background Technology

[0002] Lithium-ion batteries are typically assembled by combining individual battery cells into battery modules, then combining multiple battery modules into a battery pack, or by directly assembling multiple battery cells in series and parallel. During long-term use, issues such as welding cracks or terminal detachment can lead to electrolyte leakage, resulting in battery pack leakage. The electrolyte can conduct through gaps in the adhesive layer of the insulating film at the bottom of the casing, creating a high-voltage short circuit between the casings within the battery pack. Because the voltage of the series-connected battery cells is high, the short-circuit current can reach thousands of amperes, causing the electrolyte to heat up rapidly and triggering a thermal runaway chain reaction. Furthermore, conductive substances in the electrolyte can corrode the metal casing, further increasing the risk of short circuits and potentially causing the battery pack to run away.

[0003] In related technologies, the outer side of the core is covered with an insulating film to prevent short circuits caused by contact between the core and the casing. The insulating film usually only covers the large surface of the core and does not cover the small surface or rounded corners. When high voltage is applied, the rounded corners of the core are more prone to breakdown due to the shorter ion transport path. Therefore, how to provide an insulating film to improve the safety of the battery pack is a technical problem that urgently needs to be solved by those skilled in the art. Utility Model Content

[0004] The purpose of this application is to provide an insulating film, a battery cell, and a battery to solve the technical problem that existing insulating films are prone to high voltage breakdown of the core, affecting battery safety.

[0005] To achieve the above objectives, the technical solution adopted in this application is as follows:

[0006] In a first aspect, this application provides an insulating film for covering a wound core, comprising: a top surface covering area, a first side surface covering area, a first bottom surface covering area, a second bottom surface covering area, a second side surface covering area, and a third side surface covering area. The top surface covering area covers the top surface of the wound core. The first side surface covering areas extend from the top surface covering area along its X direction on both sides, and are used to cover the two sides of the wound core along its thickness direction, where the X direction is the length direction of the insulating film. The first bottom surface covering area extends from one of the first side surface covering areas along one side of the X direction, and is used to cover the bottom surface of the wound core. The second bottom surface covering area extends from the other first side surface covering area along one side of the X direction, and is used to cover the bottom surface of the wound core. The first bottom surface covering area and the second bottom surface covering area are connected in a continuous manner. The first and second side covering areas are at least partially overlapping; the second side covering area extends from the top covering area or the first side covering area along the Y direction on both sides respectively, the second side covering area is used to cover at least a portion of the side of the core extending along its height direction and extends from the top surface of the core to the bottom surface, the second side covering area at least covers the edge side of the top covering area in the Y direction, the Y direction being the width direction of the insulating film; the third side covering area extends from the first bottom covering area or the first side covering area along the Y direction on both sides respectively, the third side covering area is used to cover at least a portion of the side of the core extending along its height direction and extends from the bottom surface of the core to the top surface, the third side covering area at least covers the edge side of the first bottom covering area in the Y direction; wherein, the second side covering area and the third side covering area are at least partially overlapping.

[0007] In one or more embodiments of this application, in the overlapping area of ​​the second side coverage area and the third side coverage area, the third side coverage area covers the outside of the second side coverage area.

[0008] In one or more embodiments of this application, the second side covering area extends from both sides of the top covering area along the Y direction, and the second side covering area extends from both sides along the X direction with first folded edges. When the insulating film covers the core, the first folded edges are bent toward the first side covering area and cover the outside of the first side covering area; or,

[0009] The second side coverage area extends from one of the first side coverage areas along the Y direction on both sides. The second side coverage area is provided with a second folded edge on the side of the top surface coverage area along the X direction. When the insulating film is wrapped around the core, the second folded edge bends toward the top surface coverage area and wraps around the outside of the top surface coverage area. The second side coverage area is also provided with a third folded edge on the side of the second side coverage area along the Y direction. The third folded edge bends toward the other first side coverage area and wraps around the outside of the other first side coverage area.

[0010] In one or more embodiments of this application, the third side covering area extends from both sides of the first bottom covering area along the Y direction, and the third side covering area extends from both sides of the X direction with fourth folded edges. When the insulating film covers the core, the fourth folded edges bend toward the first side covering area and cover the outside of the first side covering area.

[0011] or,

[0012] The third side coverage area extends from one of the first side coverage areas along the Y direction on both sides. The third side coverage area has a fifth folded edge on the side of the bottom coverage area along the X direction. When the insulating film is wrapped around the core, the fifth folded edge bends toward the first bottom coverage area and wraps around the outside of the first bottom coverage area. The third side coverage area also has a sixth folded edge on the side of the third side coverage area along the Y direction. The sixth folded edge bends toward the other first side coverage area and wraps around the outside of the other first side coverage area.

[0013] In one or more embodiments of this application, the thickness of the second side coverage area is d1, satisfying: 0.1mm ≤ d1 ≤ 3mm; and / or,

[0014] The thickness of the third side coverage area is d2, which satisfies: 0.1mm≤d2≤3mm.

[0015] In one or more embodiments of this application, it further includes: a heat-insulating coating disposed on the outer side of the first side coverage area away from the core, the heat-insulating coating extending from the top surface of the core to the bottom surface and covering at least a portion of the first side coverage area along the X direction.

[0016] In one or more embodiments of this application, the thickness of the thermal insulation coating is d3, which satisfies: 0.2mm≤d3≤2mm.

[0017] In one or more embodiments of this application, a first bottom surface covering area is provided with a plurality of first through holes extending through its thickness direction, and a second bottom surface covering area is provided with a plurality of second through holes extending through its thickness direction. The projections of the first through holes in the thickness direction of the first bottom surface covering area and the projections of the second through holes in the thickness direction of the second bottom surface covering area do not overlap.

[0018] A guide groove is provided between two adjacent first through holes. The opening of the guide groove faces the second bottom surface coverage area, and the projection of the second through hole in the thickness direction of the second bottom surface coverage area overlaps at least partially with the projection of the guide groove in the thickness direction of the first bottom surface coverage area.

[0019] Secondly, this application also provides a battery cell, comprising: a core and an insulating film as described in any one of the first aspects, wherein the insulating film covers the outside of the core.

[0020] Thirdly, this application also provides a battery cell including the one described in the second aspect.

[0021] Based on the above technical solutions, the insulating film, battery cell, and battery provided in this application have at least the following beneficial technical effects:

[0022] The insulating film provided in this application embodiment covers the top surface of the core and the two sides of the core thickness direction by setting a top surface covering area and first side surface covering areas extending from the top surface covering area along the X direction. A first bottom surface covering area extends from one of the first side surface covering areas along the X direction to cover the bottom surface of the core. A second bottom surface covering area extends from the other first side surface covering area along the X direction to cover the bottom surface of the core by at least partially overlapping the first bottom surface covering area. Since the first bottom surface covering area and the second bottom surface covering area are folded and covered respectively, the edge side of the first bottom surface covering area and the edge side of the second bottom surface covering area are staggered, so that the electrolyte is not easy to leak out from the gaps. The insulating film of this application also extends second side covering areas from both sides of the top covering area or the first side covering area along the Y direction. These second side covering areas extend from the top of the core to the bottom surface and cover at least a portion of the sides of the core extending along its height direction. The second side covering areas at least cover the edge side of the top covering area in the Y direction, thus covering the edge of the top covering area in the Y direction. This extends the ion transport path between the core and the casing at the rounded corner top of the core, increasing the core's breakdown resistance and reducing the risk of thermal runaway in the battery cell. Simultaneously, third side covering areas extend from both sides of the first bottom covering area or the first side covering area along the Y direction. These third side covering areas extend from the bottom to the top surface and cover at least a portion of the sides of the core extending along its height direction. The second and third side covering areas at least partially overlap. Furthermore, the rounded corners of the core can be fully covered by the second and third side covering areas, extending the ion transport path between the core and the casing. The third side covering area covers at least the edge side of the first bottom covering area in the Y direction, thereby covering the edge of the first bottom covering area in the Y direction. This extends the ion transport path between the core and the casing at the bottom of the rounded corners of the core, increases the core's breakdown resistance, reduces the risk of thermal runaway of individual battery cells, and improves the safety performance of the battery. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1This is a schematic diagram of the insulating film provided in the embodiments of this application.

[0025] Figure 2 This is a schematic diagram of an insulating film provided in another embodiment of this application.

[0026] Figure 3 This is a schematic diagram of an insulating film provided in another embodiment of this application.

[0027] Figure 4 This is a schematic diagram of the insulating film-coated core provided in the embodiments of this application.

[0028] Figure 5 This is a schematic diagram of the bottom view of the insulating film-coated core provided in the embodiments of this application.

[0029] Figure 6 This is a front view of the insulating film-coated core provided in the embodiments of this application.

[0030] Figure 7 yes Figure 6 BB cross-section diagram.

[0031] Figure 8 This is an exploded structural diagram of a battery cell provided in an embodiment of this application.

[0032] In the diagram: 10-Top surface coverage area; 20-First side surface coverage area; 30-Second side surface coverage area; 40-Third side surface coverage area; 50-First bottom surface coverage area; 51-Second bottom surface coverage area; 60-Insulating coating; 101-Pole post hole; 102-Injection hole; 103-Explosion-proof valve hole; 301-First folded edge; 302-Third folded edge; 303-Second folded edge; 401-Fourth folded edge; 402-Sixth folded edge; 403-Fifth folded edge; 501-First through hole; 502-Guide groove; 511-Second through hole; 2-Core; 21-Top surface; 22-Rounded corner side; 23-Bottom surface; 24-Large surface. Detailed Implementation

[0033] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0034] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0035] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They 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. Therefore, they should not be construed as limitations on this application.

[0036] 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 one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0037] In related technologies, for the core, the insulating film is usually only wrapped around the large side of the core, not the rounded corners (R-corners). Therefore, when the battery is under high voltage, the top and bottom rounded corners of the core are more likely to be broken down due to the shorter ion transport path, which affects the safety of the battery pack.

[0038] Based on the above considerations, in order to solve the technical problem that existing insulating films are prone to high-voltage breakdown of the core, affecting battery safety, this application provides an insulating film for covering a core, comprising: a top surface covering area, a first side surface covering area, a first bottom surface covering area, a second bottom surface covering area, a second side surface covering area, and a third side surface covering area. The top surface covering area covers the top surface of the core. The first side surface covering areas extend from the top surface covering area along its X direction on both sides, and are used to cover the two sides of the core along its thickness direction, where the X direction is the length direction of the insulating film. The first bottom surface covering area extends from one of the first side surface covering areas along one side of the X direction, and is used to cover the bottom surface of the core. The second bottom surface covering area extends from the other first side surface covering area along one side of the X direction, and is used to cover the bottom surface of the core. The bottom surface of the core is covered, and the first bottom surface covering area and the second bottom surface covering area are at least partially overlapped; the second side surface covering area extends from the top surface covering area or the first side surface covering area along the Y direction on both sides respectively, the second side surface covering area is used to cover at least a portion of the side surface of the core extending along its height direction and extends from the top surface of the core to the bottom surface, the second side surface covering area at least covers the edge side of the top surface covering area in the Y direction, the Y direction being the width direction of the insulating film; the third side surface covering area extends from the first bottom surface covering area or the first side surface covering area along the Y direction on both sides respectively, the third side surface covering area is used to cover at least a portion of the side surface of the core extending along its height direction and extends from the bottom surface of the core to the top surface, the third side surface covering area at least covers the edge side of the first bottom surface covering area in the Y direction; wherein, the second side surface covering area and the third side surface covering area are at least partially overlapped.

[0039] The insulating film provided in this application embodiment covers the top surface of the core by providing a top surface covering area and first side surface covering areas extending from the top surface covering area along the X direction on both sides, so as to cover the top surface and the two major sides in the thickness direction of the core. A first bottom surface covering area extends from one of the first side surface covering areas along the X direction to cover the bottom surface of the core. A second bottom surface covering area extends from the other first side surface covering area along the X direction to cover the bottom surface of the core by at least partially overlapping the first bottom surface covering area. Since the first bottom surface covering area and the second bottom surface covering area are folded and covered respectively, the edge side of the first bottom surface covering area and the edge side of the second bottom surface covering area are staggered, so that the electrolyte is not easy to leak out from the gaps. The insulating film of this application also extends second side covering areas from both sides of the top covering area or the first side covering area along the Y direction. These second side covering areas extend from the top of the core to the bottom surface and cover at least a portion of the sides of the core extending along its height direction. The second side covering areas at least cover the edge side of the top covering area in the Y direction, thus covering the edge of the top covering area in the Y direction. This extends the ion transport path between the core and the casing at the rounded corner top of the core, increasing the core's breakdown resistance and reducing the risk of thermal runaway in the battery cell. Simultaneously, third side covering areas extend from both sides of the first bottom covering area or the first side covering area along the Y direction. These third side covering areas extend from the bottom to the top surface and cover at least a portion of the sides of the core extending along its height direction. The second and third side covering areas at least partially overlap. Furthermore, the rounded corners of the core can be fully covered by the second and third side covering areas, extending the ion transport path between the core and the casing. The third side covering area covers at least the edge side of the first bottom covering area in the Y direction, thereby covering the edge of the first bottom covering area in the Y direction. This extends the ion transport path between the core and the casing at the bottom of the rounded corners of the core, increases the core's breakdown resistance, reduces the risk of thermal runaway of individual battery cells, and improves the safety performance of the battery.

[0040] The insulating film described in this application is used to cover the outside of a winding core to insulate the core and the housing, preventing short circuits between them. The insulating film possesses excellent insulation, high-temperature resistance, flame retardancy, and mechanical strength. The insulating film can be made of materials such as polyimide (PI), polycarbonate (PC), polyethylene terephthalate (PET), polyvinyl chloride (PVC), or polyvinylidene fluoride (PVDF).

[0041] The core described in this application embodiment is composed of a positive electrode sheet, a negative electrode sheet, and a separator. The positive electrode sheet includes a positive current collector and a positive active material layer. The positive active material layer is coated on the surface of the positive current collector. The positive current collector without the positive active material layer protrudes from the positive current collector with the positive active material layer, and serves as a positive electrode tab. The negative electrode sheet includes a negative current collector and a negative active material layer. The negative active material layer is coated on the surface of the negative current collector. The negative current collector without the negative active material layer protrudes from the negative current collector with the negative active material layer, and serves as a negative electrode tab. The core can be a wound structure or a stacked structure; this application embodiment is not limited to these.

[0042] The battery cell described in this application includes a core and an electrolyte. The battery cell primarily functions by the movement of metal ions between the positive and negative electrode plates. The battery cell described in this application may include lithium-ion battery cells, lithium-sulfur battery cells, sodium-lithium-ion battery cells, sodium-ion battery cells, or magnesium-ion battery cells, etc.

[0043] The battery in this application embodiment can be applied to various electrical devices that use electricity as a power source. These electrical devices may include mobile devices (such as mobile phones, laptops, etc.), electric vehicles (such as pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc., but are not limited thereto.

[0044] The technical solution of this application will now be described in detail with reference to the accompanying drawings.

[0045] Please refer to Figure 1 and Figure 3 This application provides an insulating film for covering a core 2, comprising: a top surface covering area 10, a first side surface covering area 20, a first bottom surface covering area 50, a second bottom surface covering area 51, a second side surface covering area 30, and a third side surface covering area 40. The top surface covering area 10 covers the top surface of the core 2. The top surface of the core 2 can be understood as the surface located above along the height direction of the core 2. In some embodiments, the projection of the top surface covering area 10 along its thickness direction covers the top surface of the core 2. In some embodiments, the top surface covering area 10 further comprises an explosion-proof valve hole 103, an injection hole 102, and an electrode post hole 101. The explosion-proof valve hole 103 allows the explosion-proof valve of the core 2 to pass through. The injection hole 102 allows the injection of electrode liquid into the core 2. The electrode post hole 101 allows the electrode post to pass through and connect to the electrode tab of the core.

[0046] The first side covering area 20 extends from both sides of the top covering area 10 along the X direction, and is used to cover both sides of the core 2 along its thickness direction. The X direction can be the length direction of the insulating film. The first side covering area 20 covers both sides of the core 2 along its thickness direction, which can be understood as the first side covering area 20 covering the two major sides of the core 2. In some embodiments, the projection of each first side covering area 20 along its thickness direction covers the major side of the core 2.

[0047] A first bottom surface covering area 50 extends from one of the first side surface covering areas 20 along the X direction, and the first bottom surface covering area 50 is used to cover the bottom surface of the core 2. The bottom surface of the core 2 can be understood as the surface located below along the height direction of the core 2, and one side of the first side surface covering area 20 along the X direction can be understood as the side of one of the first side surface covering areas 20 away from the top surface covering area 10 along the X direction. In some embodiments, the projection of the first bottom surface covering area 50 along its thickness direction covers the bottom surface of the core 2.

[0048] The second bottom surface covering area 51 extends from one side of the other first side surface covering area 20 along the X direction. The second bottom surface covering area 51 is used to cover the bottom surface of the core 2. The first bottom surface covering area 50 and the second bottom surface covering area 51 are at least partially overlapped. It can be understood that the second bottom surface covering area 51 extends from the other first side surface covering area 20 along the X direction away from the top surface covering area 10. Therefore, the second bottom surface covering area 51 and the first bottom surface covering area 50 are folded relative to each other when covering the core 2. The at least partial overlap of the first bottom surface covering area 50 and the second bottom surface covering area 51 can also be understood as the projection of the second bottom surface covering area 51 along its thickness direction covering at least part of the bottom surface of the core 2. The second bottom surface covering area 51 and the first bottom surface covering area 50 are stacked. In the embodiments of this application, the projection of the second bottom surface covering area 51 along its thickness direction covers the bottom surface of the core 2. Therefore, along the Y direction, the width of the second bottom surface covering area 51 can be consistent with the width of the first bottom surface covering area 50.

[0049] The second side covering area 30 extends from the top covering area 10 or the first side covering area 20 along the Y direction on both sides, where the Y direction is the width direction of the insulating film. The second side covering area 30 covers at least a portion of the sides of the core 2 extending along its height direction and extends from the top surface of the core 2 to the bottom surface. The second side covering area 30 at least covers the edge side of the top covering area 10 in the Y direction. It is understood that the second side covering area 30 can extend from the top covering area 10 along the Y direction on both sides, or it can extend from the first side covering area 20 along the Y direction on both sides. The side of the core 2 extending along its height direction is the side of the core 2 along its length direction, that is, the rounded corner side or small facet side of the core 2 adjacent to the large facet side. It is understood that the second side covering area 30 extends from the top surface of the core 2 to the bottom surface and covers at least a portion of the small facet side or rounded corner side. The second side coverage area 30 at least covers the edge side of the top surface coverage area 10 in the Y direction, which can be understood as the second side coverage area 30 being able to wrap around the edge side of the top surface coverage area 10 in the Y direction.

[0050] The third side covering area 40 extends from both sides of the first bottom covering area 50 or the first side covering area 20 along the Y direction. The third side covering area 40 covers at least a portion of the sides of the core 2 extending along its height direction and extends from the bottom to the top surface of the core 2. The third side covering area 40 at least covers the edge side of the first bottom covering area 50 in the Y direction. The second side covering area 30 and the third side covering area 40 are at least partially overlapped. It is understood that the third side covering area 40 can extend from both sides of the first bottom covering area 50 along the Y direction, or it can extend from both sides of the first side covering area 20 along the Y direction. It is understood that the third side covering area 40 extends from the bottom to the top surface of the core 2 and covers at least a portion of the small facet side or the rounded corner side. Furthermore, the fact that the third side covering area 40 at least covers the edge side of the first bottom covering area 50 in the Y direction can be understood as the third side covering area 40 being able to completely wrap around the edge side of the first bottom covering area 50 in the Y direction. The fact that the second side coverage area 30 and the third side coverage area 40 are at least partially overlapped can be understood as meaning that, along the height direction of the core 2, the sum of the lengths of the second side coverage area 30 and the third side coverage area 40 is greater than the height of the core 2.

[0051] In this embodiment, a top surface covering area 10 and first side surface covering areas 20 extending from both sides of the top surface covering area 10 along the X direction are provided to cover the top surface of the core 2 and the two major sides of the core 2 in the thickness direction. A first bottom surface covering area 50 extending from one of the first side surface covering areas 20 along its X direction covers the bottom surface of the core 2. A second bottom surface covering area 51 extending from the other first side surface covering area 20 along its X direction covers the bottom surface of the core 2 by at least partially overlapping the first bottom surface covering area 50. Since the first bottom surface covering area 50 and the second bottom surface covering area 51 are folded and covered relative to each other, the insulating film is staggered on the edge side of the first bottom surface covering area 50 and the edge side of the second bottom surface covering area 51, thereby making it difficult for the electrolyte to leak out from the gaps. The insulating film of this application also extends second side covering areas 30 from both sides of the top surface covering area 10 or the first side covering area 20 along the Y direction. This allows the second side covering areas 30 to extend from the top surface of the core 2 to the bottom surface and cover at least a portion of the side surface of the core 2 along its Y direction. The second side covering areas 30 at least cover the edge side of the top surface covering area 10 in the Y direction, thereby covering the edge of the top surface covering area 10 in the Y direction. This extends the ion transport path between the core 2 and the casing at the rounded corner top of the core 2, increasing the core's breakdown resistance and reducing the risk of thermal runaway in the battery cell. Simultaneously, third side covering areas 40 extend from both sides of the first bottom surface covering area 50 or the first side covering area 20 along the Y direction. This allows the third side covering areas 40 to extend from the bottom surface to the top surface and cover at least a portion of the side surface of the core 2 along its Y direction. The second side covering areas 30 and the third side covering areas 40 are at least partially overlapping. Furthermore, the rounded corners of the core can be fully covered by the second side covering area 30 and the third side covering area 40, which extends the ion transport path between the core and the shell. The third side covering area 40 covers at least the edge side of the first bottom covering area 50 in the Y direction, thereby covering the edge of the first bottom covering area 50 in the Y direction. This extends the ion transport path between the core and the shell at the bottom of the rounded corners of the core, increases the core's resistance to breakdown, reduces the risk of thermal runaway of the battery cell, and improves the safety performance of the battery.

[0052] Please refer to Figure 4 In some embodiments, in the overlapping area of ​​the second side coverage area 30 and the third side coverage area 40, the third side coverage area 40 covers the outside of the second side coverage area 30.

[0053] It is understandable that, since the second side covering area 30 extends from the top surface of the core 2 to the bottom surface, and the third side covering area 40 extends from the bottom surface of the core 2 to the top surface, the overlapping area of ​​the second side covering area 30 and the third side covering area 40 can be located in the middle of the core 2, that is, in the area away from the top or bottom surface.

[0054] In this embodiment, by covering the outer side of the second side covering area 30 with the third side covering area 40, interference between the upper second side covering area 30 and the edge of the housing can be prevented when the core 2 is inserted into the housing, and the core can also be prevented from being damaged by impact, thereby improving the insertion speed of the core. When folding the insulating film, the second side covering area 30 can be folded first, and then the third side covering area 40 can be folded so that it covers the outer side of the second side covering area 30.

[0055] Please refer to Figure 1 and Figure 2 In order to ensure that the second side coverage area 30 covers at least the edge side of the top surface coverage area 10 in the Y direction, when the second side coverage area 30 extends from the top surface coverage area 10 along both sides in the Y direction, the second side coverage area 30 extends the first folded edge 301 along both sides in the X direction. When the insulating film covers the core 2, the first folded edge 301 bends toward the first side coverage area 20 and covers the outside of the first side coverage area 20.

[0056] It is understandable that the second side covering area 30 extends from both sides of the top covering area 10 along the Y direction, thus the two sides of the top covering area 10 in the Y direction are directly integrated with the second side covering area 30. Therefore, the two edges of the top covering area 10 in the Y direction can be wrapped by the second side covering area 30, resulting in a seamless connection between the two sides of the top covering area 10 in the Y direction. The first folded edge 301 can be connected to the first side covering area 20 through mechanical fitting, adhesive bonding, or other methods.

[0057] In this embodiment, second side covering areas 30 are extended from both sides of the top covering area 10 along the Y direction, and first folded edges 301 are extended from both sides of the second side covering areas 30 along the X direction. This makes the two side edges of the top covering area 10 integrally connected with the second side covering areas 30, wrapping the rounded top of the core 2. At the same time, the first folded edges 301 wrap the edge side of the first side covering area 20, thereby extending the ion transport path between the core 2 and the shell, increasing the breakdown resistance of the core 2 at the rounded corners, and reducing the risk of thermal runaway of the battery cell.

[0058] Please refer to Figure 3In some other embodiments, in order to ensure that the second side coverage area 30 at least covers the Y-direction edge of the top surface coverage area 10, the second side coverage area 30 may also extend from both sides of the first side coverage area 20 along the Y-direction. Specifically, when the second side coverage area 30 extends from both sides of one of the first side coverage areas 20 along the Y-direction, the side of the second side coverage area 30 near the top surface coverage area 10 is provided with a second folded edge 303. When the insulating film covers the core 2, the second folded edge 303 bends toward the top surface coverage area 10 and covers the outside of the top surface coverage area 10. The side of the second side coverage area 30 along the Y-direction is also provided with a third folded edge 302, which bends toward the other first side coverage area 20 and covers the outside of the other first side coverage area 20.

[0059] It is understandable that the second side coverage area 30 can also extend from one of the first side coverage areas 20 near the top coverage area 10. In this case, a second folded edge 303 is provided on the side of the second side coverage area 30 near the top coverage area 10. The second folded edge 303 bends towards the top coverage area 10 and covers the outside of the top coverage area 10, thereby wrapping the two edges of the top coverage area 10 along the Y direction. The second folded edge 303 can be connected to the top coverage area 10 by mechanical fitting, adhesive bonding, or other means. The third folded edge 302 can be connected to the first side coverage area 20 by mechanical fitting, adhesive bonding, or other means.

[0060] In this embodiment, the above-mentioned arrangement allows the second folded edge 303 of the second side covering area 30 to bend toward the top covering area 10 and wrap around the outside of the top covering area 10, thereby wrapping the rounded top of the core 2. At the same time, the third folded edge 302 wraps the edge of the first side covering area 20, thereby extending the ion transport path between the core 2 and the shell, increasing the breakdown resistance of the core 2 at the rounded corner, and reducing the risk of thermal runaway of the battery cell.

[0061] Please refer to Figure 1 and Figure 2 In some embodiments, in order to ensure that the third side coverage area 40 at least covers the Y-direction edge side of the first bottom coverage area 50, the third side coverage area 40 extends from both sides of the first bottom coverage area 50 along the Y direction, and the third side coverage area 40 extends from both sides of the X direction with fourth folded edges 401. When the insulating film covers the core 2, the fourth folded edges 401 bend toward the first side coverage area 20 and cover the outside of the first side coverage area 20.

[0062] It is understandable that the third side covering area 40 extends from both sides of the first bottom covering area 50 along the Y direction, thus the two sides of the first bottom covering area 50 in the Y direction are directly integrated with the third side covering area 40. Therefore, the two edges of the first bottom covering area 50 in the Y direction can be wrapped by the third side covering area 40, resulting in a seamless connection between the two sides of the first bottom covering area 50 in the Y direction. The fourth folded edge 401 can be connected to the first side covering area 20 through mechanical fitting, adhesive bonding, or other methods.

[0063] In this embodiment, by extending third side coverage areas 40 on both sides of the first bottom coverage area 50 along the Y direction, and extending fourth folded edges 401 on both sides of the third side coverage areas 40 along the X direction, the two side edges of the first bottom coverage area 50 are integrally connected with the third side coverage areas 40, thus wrapping the rounded bottom of the core 2. At the same time, the edge side of the first side coverage area 20 is wrapped by the fourth folded edges 401, thereby extending the ion transport path between the core 2 and the shell, increasing the breakdown resistance of the core 2 at the rounded corners, and reducing the risk of thermal runaway of the battery cell.

[0064] Please refer to Figure 3 In some other embodiments, in order to ensure that the third side coverage area 40 at least covers the Y-direction edge of the first bottom coverage area 50, the third side coverage area 40 may extend from both sides of the first side coverage area 20 along the Y-direction. Specifically, when the third side coverage area 40 extends from both sides of one of the first side coverage areas 20 along the Y-direction, the third side coverage area 40 is provided with a fifth folded edge 403 on the side near the first bottom coverage area 50. When the insulating film covers the core 2, the fifth folded edge 403 bends toward the first bottom coverage area 50 and covers the outside of the first bottom coverage area 50. The third side coverage area 40 is also provided with a sixth folded edge 402 on the side along the Y-direction, and the sixth folded edge 402 bends toward the other first side coverage area 20 and covers the outside of the other first side coverage area 20.

[0065] It is understood that the third side covering area 40 can also extend from one of the first side covering areas 20 near the first bottom covering area 50. In some embodiments, the third side covering area 40 and the second side covering area 30 can extend from the same first side covering area 20, or they can extend from two different first side covering areas 20. In this case, a fifth folded edge 403 is provided on the side of the third side covering area 40 near the first bottom covering area 50. The fifth folded edge 403 bends towards the first bottom covering area 50 and covers the outer side of the first bottom covering area 50, thereby wrapping the two edges of the first bottom covering area 50 along its Y direction. The fifth folded edge 403 can be connected to the first bottom covering area 50 by mechanical fitting, adhesive bonding, or other means. The sixth folded edge 402 can be connected to the first side covering area 20 by mechanical fitting, adhesive bonding, or other means.

[0066] In this embodiment, the above-mentioned arrangement allows the fifth fold 403 of the third side coverage area 40 to bend toward the first bottom coverage area 50 and wrap around the outside of the first bottom coverage area 50, thereby wrapping the rounded bottom of the core 2. At the same time, the sixth fold 402 wraps the edge of the first side coverage area 20, thereby extending the ion transport path between the core 2 and the shell, increasing the breakdown resistance of the core 2 at the rounded corner, and reducing the risk of thermal runaway of the battery cell.

[0067] In some embodiments, along the X direction, the sum of the lengths h2 of the second side covering area 30 and h1 of the third side covering area 40 is greater than the height of the core 2, so that the second side covering area 30 and the third side covering area 40 can completely cover the small face side or rounded corner side of the core 2, while the third side covering area 40 can cover the outside of the second side covering area 30, so that the core 2 can be easily inserted into the shell and interference between the second side covering area 30 and the edge of the shell can be avoided.

[0068] In some embodiments, the thickness of the second side coverage area 30 is d1, satisfying the condition: 0.1mm ≤ d1 ≤ 3mm. For example, d1 = 0.1mm, 0.3mm, 0.5mm, 0.7mm, 1.0mm, 1.3mm, 1.5mm, 1.8mm, 2.1mm, 2.3mm, 2.6mm, 2.8mm, or 3mm, or any value between the two. In some embodiments, the thickness of the third side coverage area 40 is d2, satisfying the condition: 0.1mm ≤ d2 ≤ 3mm. For example, d2 = 0.1mm, 0.3mm, 0.5mm, 0.7mm, 1.0mm, 1.3mm, 1.5mm, 1.8mm, 2.1mm, 2.3mm, 2.6mm, 2.8mm, or 3mm, or any value between the two. The thicknesses of the second side coverage area 30 and the third side coverage area 40 can be set differently depending on the insulating film material.

[0069] In some embodiments, please refer to Figure 2 The insulating film also includes a heat-insulating coating 60, which is disposed on the outer side of the first side coverage area 20 away from the core 2. The heat-insulating coating 60 extends from the top surface of the core 2 to the bottom surface and covers at least part of the first side coverage area 20 in the X direction.

[0070] Understandably, in the Y direction, the width of the heat-insulating coating 60 can be the same as the width of the first side coverage area 20. In the X direction, the length of the heat-insulating coating 60 can extend from the top surface of the core 2 to the bottom surface, so that it at least partially covers the first side coverage area 20 along the Y direction. The heat-insulating coating 60 can be a material that vaporizes upon heating.

[0071] In this embodiment, by providing a heat-insulating coating 60 that extends from the top to the bottom of the core 2 away from the outer side of the first side coverage area 20, when the top cover of the housing is laser welded to the housing, the heat-insulating coating 60 absorbs the heat generated by the laser by vaporizing when heated, thereby preventing the laser from penetrating the first side coverage area 20 and damaging the core 2, avoiding the formation of short circuit points, improving the yield of battery cells, and reducing the risk of large self-discharge and thermal runaway of battery cells due to laser leakage.

[0072] In some embodiments, the heat insulation coating 60 is primarily made of phenolic resin doped with zirconium oxide. The proportion of zirconium oxide doping is required for different laser welding power equipment, typically ranging from 20% to 50%. In some embodiments, the thickness d3 of the heat insulation coating 60 is required to meet the following condition: 0.2mm ≤ d3 ≤ 2mm. For example, d3 can be 0.2mm, 0.4mm, 0.6mm, 0.8mm, 1.0mm, 1.2mm, 1.4mm, 1.6mm, 1.8mm, or 2.0mm, or any value between these two. This allows the coating to absorb the heat generated by the laser and vaporize, preventing damage to the core 2 from the laser.

[0073] In some embodiments, the second bottom surface covering area 51 is disposed close to the core 2 relative to the first bottom surface covering area 50, that is, the first bottom surface covering area 50 is disposed outside the second bottom surface covering area 51.

[0074] Please refer to Figure 1 , Figure 2 , Figure 3 , Figure 5 , Figure 6 and Figure 7 The first bottom surface covering area 50 is provided with a plurality of first through holes 501 extending through its thickness direction, and the second bottom surface covering area 51 is provided with a plurality of second through holes 511 extending through its thickness direction. The projections of the first through holes 501 in the thickness direction of the first bottom surface covering area 50 and the projections of the second through holes 511 in the thickness direction of the second bottom surface covering area 51 do not overlap.

[0075] It is understandable that the first through hole 501 and the second through hole 511 are offset in the thickness direction. The first through hole 501 can be arranged in one row, two rows, three rows or more, and the second through hole 511 can also be arranged in one row, two rows, three rows or more.

[0076] In this embodiment of the application, the first through hole 501 and the second through hole 511 are provided so that the electrolyte can quickly penetrate into the core 2, thereby improving the wetting rate of the core 2.

[0077] In some embodiments, a guide groove 502 is provided between two adjacent first through holes 501, the opening of the guide groove 502 faces the second bottom surface coverage area 51, and the projection of the second through hole 511 in the thickness direction of the second bottom surface coverage area 51 overlaps at least partially with the projection of the guide groove 502 in the thickness direction of the first bottom surface coverage area 50.

[0078] It is understood that the guide groove 502 is located on the side of the first bottom surface covering area 50 facing the core 2 and the inside of the core 2, and can connect the adjacent first through hole 501 and second through hole 511.

[0079] In this embodiment of the application, the above-mentioned arrangement facilitates the rapid wetting of the electrolyte into the core 2 through the first through hole 501, the guide groove 502 and the second through hole 511, thereby improving the liquid absorption rate of the core 2.

[0080] On the other hand, this application also provides a single battery cell, please refer to... Figure 8 It includes: core 2 and the insulating film of any of the preceding items, wherein the insulating film covers the outside of core 2.

[0081] Please refer to Figure 8 In some embodiments, the core 2 includes a top surface 21, a bottom surface 23, two large surfaces 24 oppositely arranged, and rounded side surfaces 22 oppositely arranged. The top surface coverage area 10 of the insulating film covers the top surface 21, the two first side surface coverage areas 20 of the insulating film cover the two large surfaces 24, the two second side surface coverage areas 30 and the two third side surface coverage areas 40 of the insulating film cover the two rounded side surfaces 22, and the first bottom surface coverage area 50 and the second bottom surface coverage area 51 of the insulating film overlap and cover the bottom surface 23, with the first bottom surface coverage area 50 located outside the second bottom surface coverage area 51. This extends the length of the ion pathway at the rounded corners of the core 2, increases the core's breakdown resistance, reduces the risk of thermal runaway in individual battery cells, and improves battery safety.

[0082] On the other hand, this application also provides a battery, including a battery cell.

[0083] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. An insulating film for covering a core (2), characterized in that, include: Top surface coverage area (10) covers the top surface of the core (2); The first side covering area (20) extends from the top covering area (10) along its X direction on both sides respectively. The first side covering area (20) is used to cover the two sides of the core (2) along its thickness direction. The X direction is the length direction of the insulating film. A first bottom surface covering area (50) extends from one of the first side surface covering areas (20) along one side in the X direction, and the first bottom surface covering area (50) is used to cover the bottom surface of the core (2); The second bottom surface covering area (51) extends from one side of the other first side surface covering area (20) along the X direction. The second bottom surface covering area (51) is used to cover the bottom surface of the core (2), and the first bottom surface covering area (50) and the second bottom surface covering area (51) are at least partially overlapped. The second side covering area (30) extends from the top covering area (10) or the first side covering area (20) on both sides along the Y direction. The second side covering area (30) is used to cover at least a portion of the side of the core (2) extending along its height direction and extends from the top surface of the core (2) to the bottom surface. The second side covering area (30) covers at least the edge side of the top covering area (10) in the Y direction, where the Y direction is the width direction of the insulating film. The third side covering area (40) extends from the first bottom covering area (50) or the first side covering area (20) along the Y direction on both sides respectively. The third side covering area (40) is used to cover at least a portion of the side of the core (2) extending along its height direction and extends from the bottom surface of the core (2) to the top surface. The third side covering area (40) covers at least the edge side of the first bottom covering area (50) in the Y direction. The second side covering area (30) and the third side covering area (40) are at least partially overlapped.

2. The insulating film according to claim 1, characterized in that, In the overlapping area of ​​the second side coverage area (30) and the third side coverage area (40), the third side coverage area (40) covers the outside of the second side coverage area (30).

3. The insulating film according to claim 2, characterized by The second side covering area (30) extends from the top covering area (10) along both sides in the Y direction, and the second side covering area (30) extends the first folded edge (301) along both sides in the X direction. When the insulating film covers the core (2), the first folded edge (301) bends toward the first side covering area (20) and covers the outside of the first side covering area (20); or, The second side covering area (30) extends from one of the first side covering areas (20) along the Y direction on both sides. The second side covering area (30) is provided with a second folded edge (303) on the side of the top surface covering area (10) along the X direction. When the insulating film covers the core (2), the second folded edge (303) bends toward the top surface covering area (10) and covers the outside of the top surface covering area (10). The second side covering area (30) is also provided with a third folded edge (302) on the side of the Y direction. The third folded edge (302) bends toward the other first side covering area (20) and covers the outside of the other first side covering area (20).

4. The insulating film according to claim 3, characterized by The third side covering area (40) extends from the first bottom covering area (50) along the Y direction on both sides respectively. The third side covering area (40) extends the fourth fold (401) along the X direction on both sides respectively. When the insulating film covers the core (2), the fourth fold (401) bends toward the first side covering area (20) and covers the outside of the first side covering area (20). or, The third side covering area (40) extends from one of the first side covering areas (20) along the Y direction on both sides. The third side covering area (40) is provided with a fifth fold (403) on the side of the bottom covering area along the X direction. When the insulating film covers the core (2), the fifth fold (403) bends toward the first bottom covering area (50) and covers the outside of the first bottom covering area (50). The third side covering area (40) is also provided with a sixth fold (402) on the side of the Y direction. The sixth fold (402) bends toward the other first side covering area (20) and covers the outside of the other first side covering area (20).

5. The insulating film according to claim 4, characterized by The thickness of the second side coverage area (30) is d1, satisfying: 0.1mm ≤ d1 ≤ 3mm; and / or, The thickness of the third side coverage area (40) is d2, which satisfies: 0.1mm≤d2≤3mm.

6. The insulating film according to claim 1, characterized by Also includes: An insulating coating (60) is provided on the outer side of the first side coverage area (20) away from the core (2), the insulating coating (60) extending from the top surface of the core (2) to the bottom surface and covering at least a portion of the first side coverage area (20) along the X direction.

7. The insulating film according to claim 6, characterized by The thickness of the heat insulation coating (60) is d3, which satisfies: 0.2mm≤d3≤2mm.

8. The insulating film according to claim 1, characterized by The first bottom surface covering area (50) is provided with a plurality of first through holes (501) penetrating its thickness direction, and the second bottom surface covering area (51) is provided with a plurality of second through holes (511) penetrating its thickness direction. The projection of the first through hole (501) in the thickness direction of the first bottom surface covering area (50) and the projection of the second through hole (511) in the thickness direction of the second bottom surface covering area (51) do not overlap. A guide groove (502) is provided between two adjacent first through holes (501). The opening of the guide groove (502) faces the second bottom surface coverage area (51), and the projection of the second through hole (511) in the thickness direction of the second bottom surface coverage area (51) overlaps at least partially with the projection of the guide groove (502) in the thickness direction of the first bottom surface coverage area (50).

9. A single battery cell, characterized in that, include: Core (2) The insulating film according to any one of claims 1 to 8, wherein the insulating film covers the outside of the core (2).

10. A battery, characterized by Includes the battery cell as described in claim 9.

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