A battery and a battery system

Abstract

This application discloses a battery and a battery system. The battery includes a cell electrode assembly, a heat insulation layer, a heat shrinkable layer, and a casing. The cell electrode assembly is disposed within the casing, the heat shrinkable layer covers the outside of the cell electrode assembly, and the heat insulation layer is disposed between the cell electrode assembly and the heat shrinkable layer. The heat shrinkable layer is used to shrink under heat to bind the cell electrode assembly. In this application, during the expansion process of the cell electrode assembly, the heat shrinkable layer is heated, and the heat shrinkable layer shrinks under heat to bind the cell electrode assembly, which can reduce the degree of expansion of the cell electrode assembly, thereby reducing the risk of electrode breakage and battery size defects caused by dimensional deviations after battery expansion.

Description

Technical Field

[0001] This application belongs to the field of battery technology, specifically relating to a battery and a battery system. Background Technology

[0002] During battery cycling, the positive and negative electrodes may expand, causing the cell electrode assembly to expand, which can affect battery performance.

[0003] For example, with the promotion and widespread application of battery technology, people's demands for battery capacity and safety are increasing. In order to improve battery capacity, silicon doping is usually used to treat the materials that contribute to the battery's capacity.

[0004] However, after silicon doping, the battery is prone to expansion during the formation stage. After the battery expands, the size exceeds the tolerance, and the electrode is easily damaged during the expansion process, which seriously affects the safety and performance of the battery. Utility Model Content

[0005] This application aims to provide a battery and battery system that can reduce the risk of electrode damage during the expansion of the cell electrode assembly.

[0006] To solve the above-mentioned technical problems, this application is implemented as follows:

[0007] In a first aspect, embodiments of this application propose a battery, including a cell electrode assembly, a heat insulation layer, a heat shrinkable layer, and a casing;

[0008] The battery cell electrode assembly is disposed inside the housing, the heat shrinkable layer covers the outside of the battery cell electrode assembly, the heat insulation layer is disposed between the battery cell electrode assembly and the heat shrinkable layer, and the heat shrinkable layer is used to shrink under heat to bind the battery cell electrode assembly.

[0009] Optionally, with the height direction of the battery cell electrode assembly as the first direction, the heat shrinkable layer is arranged around the first direction to form a first enclosing space, and both the heat insulation layer and the battery cell electrode assembly are disposed in the first enclosing space;

[0010] The cell electrode assembly has an outer peripheral surface, at least 90% of the area of ​​which is located within the first enclosing space, or, along the first direction, the edge of the heat-shrinkable layer extends beyond the edge of the electrode sheet in the cell electrode assembly.

[0011] Optionally, the heat-shrinkable layer includes a plurality of shrinkable portions, which are arranged around the first direction to form the first enclosing space, and the plurality of shrinkable portions are an integral structure.

[0012] Optionally, the heat-shrinkable layer includes a plurality of shrink sleeves, the battery cell electrode assembly has an outer peripheral surface, the plurality of shrink sleeves are sleeved on the outer peripheral surface, and the plurality of shrink sleeves are arranged at intervals along a first direction.

[0013] Optionally, the battery further includes multiple limiting structures, which are disposed on the inner side of the housing or on the side of the heat insulation layer facing the heat shrinkable layer. Along the first direction, the multiple limiting structures are arranged at intervals, and the shrinkable sleeve is located between two adjacent limiting structures.

[0014] Optionally, with the height direction of the battery cell electrode assembly as the first direction, the heat insulation layer is arranged around the first direction to form a second enclosing space;

[0015] The cell electrode assembly has an outer peripheral surface, at least 90% of which is located within the second enclosing space, or, along the first direction, the edge of the insulation layer extends beyond the edge of the heat-shrinkable layer.

[0016] Optionally, the heat insulation layer includes a plurality of heat insulation portions, which surround the first aspect to form the second enclosing space, and the outer peripheral surface of the battery cell electrode assembly includes a plurality of side surfaces, each of which is opposite to one of the heat insulation portions;

[0017] The multiple heat insulation components are either separate structures or they are an integral structure.

[0018] Optionally, the heat-shrinkable layer includes a heat-shrinkable substrate and an embedded structure. The heat-shrinkable substrate is disposed between the heat insulation layer and the shell. The embedded structure includes a plurality of negative expansion particles, which are embedded within the heat-shrinkable substrate.

[0019] Alternatively, any one of the following conditions must be met:

[0020] A. The battery further includes a first encapsulation film, which covers all surfaces of the heat-shrinkable layer;

[0021] B. The battery further includes a second encapsulation film, which covers all surfaces of the heat insulation layer;

[0022] C. The battery further includes an insulating film layer, which covers at least the outer peripheral surface of the cell electrode assembly, and the heat insulation layer is disposed on the side of the insulating film layer away from the cell electrode assembly;

[0023] D. The battery further includes a first adhesive layer, which is disposed on the side of the heat insulation layer near the cell electrode assembly. The first adhesive layer bonds the heat insulation layer to the cell electrode assembly or bonds the heat insulation layer to the insulating film layer on the outer peripheral surface of the cell electrode assembly.

[0024] E. The battery further includes a second adhesive layer, which is disposed on the side of the heat-shrinkable layer near the heat insulation layer, and the second adhesive layer bonds the heat-shrinkable layer and the heat insulation layer.

[0025] Secondly, embodiments of this application propose a battery system including a heating element and a battery as described above. The heating element is disposed on the outside of the battery and in contact with the casing of the battery. The heating element is used to heat the battery.

[0026] In the embodiments of this application, during the expansion of the battery cell electrode assembly, the heat-shrinkable layer is heated. The heat-shrinkable layer shrinks under heat, which can bind the battery cell electrode assembly and reduce the degree of expansion. This reduces the risk of electrode breakage and battery size defects caused by dimensional deviations after battery expansion, and also prevents the bonding stability of the active materials on the electrodes from being affected by the expansion of the battery cell electrode assembly. In addition, the heat insulation layer acts as a heat insulation layer, which can reduce the negative impact of the high temperature of the heat-shrinkable layer on the battery cell electrode assembly. For example, high temperature can affect the activity of the electrode materials of the battery cell electrode assembly. At the same time, during the thermal safety test of the battery, it can prevent the heat of the battery cell electrode assembly from being transferred to the casing, thereby reducing the risk of casing melting caused by the heat of the battery cell electrode assembly being transferred to the casing.

[0027] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the accompanying drawings used in the description of the embodiments will be briefly introduced below, wherein:

[0029] Figure 1 This is a schematic diagram of the structure of the battery cell body and the casing provided in the embodiments of this application;

[0030] Figure 2 This is a schematic diagram of the overall structure of a battery cell body provided in an embodiment of this application;

[0031] Figure 3 This is a cross-sectional schematic diagram of a battery cell body provided in an embodiment of this application;

[0032] Figure 4 yes Figure 3 The center circle shows an enlarged schematic diagram of part A;

[0033] Figure 5 yes Figure 3 The center circle shows an enlarged schematic diagram of section B;

[0034] Figure 6 This is a schematic diagram of the structure of the cell electrode assembly in the battery provided in the embodiments of this application;

[0035] Figure 7 This is a schematic diagram of the structure of a heat-shrinkable layer provided in an embodiment of this application;

[0036] Figure 8 This is a schematic diagram of another battery body structure provided in an embodiment of this application;

[0037] Figure 9 This is a schematic diagram of the cooperative structure of a heat insulation layer, an insulating film layer, and a battery cell electrode assembly provided in an embodiment of this application;

[0038] Figure 10 This is a schematic diagram of the structure of a heat insulation layer provided in an embodiment of this application;

[0039] Figure 11 This is a schematic diagram of another cooperative structure of the heat insulation layer, the insulating film layer and the battery cell electrode assembly provided in the embodiments of this application;

[0040] Figure 12 This is a schematic diagram of another heat insulation layer provided in an embodiment of this application;

[0041] Figure 13 This is a schematic diagram of the structure of the cell electrode assembly and insulating film layer in the battery provided in the embodiments of this application;

[0042] Figure 14 This is a schematic diagram of the structure of the insulating film layer in the battery provided in the embodiments of this application;

[0043] Figure 15 This is a schematic diagram of the overall structure of the battery provided in the embodiments of this application;

[0044] Figure 16 This is a cross-sectional schematic diagram of the battery provided in an embodiment of this application;

[0045] Figure 17 yes Figure 16 The center circle shows an enlarged schematic diagram of section C.

[0046] Figure label:

[0047] 10-Cell body, 11-Cell electrode assembly, 111-Outer peripheral surface, 112-First top surface, 113-First bottom surface, 12-Insulating film layer, 13-Heat insulation layer, 131-First heat insulation part, 132-Second heat insulation part, 133-Second enclosing space, 14-Heat shrinkable layer, 141-First shrinkable part, 142-Second shrinkable part, 143-First enclosing space, 144-Shrinkable sleeve, 15-Limiting structure, 151-Limiting component;

[0048] 20-Housing shell; 30-Top cover assembly; 31-Cover body; 32-Lower plastic. Detailed Implementation

[0049] The embodiments of this application will now be described in detail. Examples of these embodiments are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0050] The terms "first" and "second" in the specification and claims of this application may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise stated, "multiple" means two or more. Furthermore, "and / or" in the specification and claims indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0051] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, 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.

[0052] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0053] The battery and battery system provided in this application will be described in detail below with reference to the accompanying drawings, through specific embodiments and application scenarios.

[0054] In a first aspect, embodiments of this application propose a battery, referring to... Figures 1 to 5The battery includes a casing 20 and a cell body 10 disposed within the casing 20. The cell body 10 includes a cell electrode assembly 11, a heat insulation layer 13, and a heat shrinkable layer 14. The cell electrode assembly 11 is disposed within the casing 20, the heat shrinkable layer 14 covers the outside of the cell electrode assembly 11, and the heat insulation layer 13 is disposed between the cell electrode assembly 11 and the heat shrinkable layer 14. The heat shrinkable layer 14 is used to shrink under heat to bind the cell electrode assembly 11.

[0055] The battery can be a lithium-ion battery, such as a high-nickel lithium battery, a lithium manganese oxide battery, a ternary lithium battery, a lithium iron phosphate battery, or a lithium titanate battery. The cell electrode assembly 11 includes multiple electrode sheets, including positive and negative electrode sheets. The cell electrode assembly 11 can be a wound core or a stacked assembly.

[0056] The heat insulation layer 13 serves a heat insulation function. The material of the heat insulation layer 13 is an insulating material, such as mica, aerogel felt, or fiberglass composite insulation material. The heat insulation layer 13 can be a flexible heat insulation layer. The heat shrinkable layer 14 is easily shrunk by heat. As one example, the heat shrinkable layer 14 includes a flexible heat shrinkable substrate and negative expansion particles, with the negative expansion particles embedded within the heat shrinkable substrate. As another example, the heat shrinkable layer 14 is entirely a flexible heat shrink film. As yet another example, the material of the heat shrinkable layer 14 is a negative expansion material.

[0057] The insulation layer 13 and the heat shrinkable layer 14 can be a single-layer structure or a multi-layer structure, which can be flexibly set according to actual needs, and no limitation is made here.

[0058] Taking a square battery as an example, the cell electrode assembly 11 has mutually perpendicular height, length, and thickness directions. Taking the height direction of the cell electrode assembly 11 as the first direction, the length direction as the second direction, and the thickness direction as the third direction, the first direction can be referenced... Figure 2 and Figure 8 The direction indicated by the arrow D in the middle; the second direction can be referenced. Figure 2 and Figure 8 The direction indicated by the arrow E in the middle can be referenced for third-party directions. Figure 2 and Figure 8 The direction indicated by the arrow F in the middle.

[0059] Reference Figure 7 and Figure 10 The heat-shrinkable layer 14 includes at least two first shrinkage portions 141 opposite each other along a third direction, and the heat insulation layer 13 includes at least two first heat insulation portions 131 opposite each other along a third direction. That is, the heat insulation layer 13 and the heat-shrinkable layer 14 need to be provided at least on the large surface of the cell electrode assembly 11 to ensure effective restraint of the cell electrode assembly 11.

[0060] In this embodiment, during the expansion of the cell electrode assembly 11, the heat-shrinkable layer 14 is heated. The heat-shrinkable layer 14 shrinks under heat, which can bind the cell electrode assembly 11 and reduce the degree of expansion. This reduces the risk of electrode breakage and battery size defects caused by dimensional deviations after battery expansion, and also prevents the bonding stability of the active material on the electrode from being affected by the expansion of the cell electrode assembly 11. In addition, the heat insulation layer 13 acts as a heat insulation layer, which can reduce the negative impact of the high temperature of the heat-shrinkable layer 14 on the cell electrode assembly 11. For example, high temperature can affect the activity of the electrode material of the cell electrode assembly 11. At the same time, during the thermal safety test of the battery, it can prevent the heat of the cell electrode assembly 11 from being transferred to the casing 20, which can reduce the risk of the casing 20 melting and breaking due to the heat of the cell electrode assembly 11 being transferred to the casing 20.

[0061] Among them, dimensional deviation refers to dimensions exceeding the allowable tolerance range. The battery thermal safety test process can be as follows: heating one side of the battery to trigger thermal runaway; if the casing 20 does not melt, it is considered OK; if the casing 20 melts, it is considered NG.

[0062] As an example, during the battery formation stage, the battery is heated by a heating element. When the battery is heated, the heat-shrinkable layer 14 shrinks and binds the cell electrode assembly 11. The battery testing process after formation can be as follows: After the battery formation is completed, the shape of the casing 20 is observed, and the battery is disassembled to analyze the electrodes. If there are phenomena such as electrode material damage, lithium plating on the electrodes, or battery swelling, it is judged as NG. If there are no such phenomena, it is judged as OK.

[0063] During the battery formation stage, the battery is heated. When the battery is heated, the heat-shrinkable layer 14 shrinks and binds the cell electrode assembly 11, which can reduce the expansion of the cell electrode assembly 11 in the silicon-doped battery during the formation stage. In addition, the heat insulation layer 13 plays a heat insulation role, which can reduce the negative impact of high temperature on the cell electrode assembly 11 during the process of heating the cell during the battery formation stage.

[0064] In some embodiments, refer to Figure 6 and Figure 7 With the height direction of the battery cell electrode assembly 11 as the first direction, the heat-shrinkable layer 14 is arranged around the first direction to form a first enclosing space 143. Both the heat insulation layer 13 and the battery cell electrode assembly 11 are disposed within the first enclosing space 143. The battery cell electrode assembly 11 has an outer peripheral surface 111, with at least 90% of the area of ​​the outer peripheral surface 111 located within the first enclosing space 143. In one embodiment, at least 95% of the area of ​​the outer peripheral surface 111 is located within the first enclosing space 143. In this embodiment, when the heat-shrinkable layer 14 shrinks due to heat, it binds the periphery of the battery cell electrode assembly 11, ensuring a binding effect on the battery cell electrode assembly 11 and thus effectively preventing the battery cell electrode assembly 11 from expanding.

[0065] The cell electrode assembly 11 also includes a separator. Along the first direction, the height of the separator is greater than the height of the electrode sheet, the height of the cell electrode assembly 11 is equal to the height of the separator, and the height of the heat shrinkable layer 14 is less than or equal to the height of the cell electrode assembly 11.

[0066] Before the heat-shrinkable layer 14 shrinks due to heat, the electrode sheets in the cell electrode assembly 11 are located within the first enclosing space 143. After the heat-shrinkable layer 14 shrinks due to heat, its height is reduced to a certain extent. By controlling the height of the heat-shrinkable layer 14 after heat shrinkage, the electrode sheets in the cell electrode assembly 11 can still be located within the first enclosing space 143 after the heat-shrinkable layer 14 shrinks due to heat, so as to ensure the entire circumference of the electrode sheets is bound.

[0067] In some embodiments, before and after the heat shrinkable layer 14 is heated and shrunk, the edge of the heat shrinkable layer 14 extends beyond the edge of the electrode in the cell electrode assembly 11 along the first direction. At this time, the height of the heat shrinkable layer 14 is greater than the height of the electrode, so as to ensure that the heat shrinkable layer 14 can bind the entire circumference of the electrode after it is heated and shrunk.

[0068] Reference Figure 6 The cell electrode assembly 11 has a first top surface 112, an outer peripheral surface 111, and a first bottom surface 113. (Refer to...) Figure 4 The upper surface of the heat-shrinkable layer 14 is flush with the first top surface 112 of the cell electrode assembly 11. (Refer to...) Figure 6 The lower surface of the heat-shrinkable layer 14 is higher than the first bottom surface 113 of the cell electrode assembly 11. Along the first direction, the distance between the lower surface of the heat-shrinkable layer 14 and the first bottom surface 113 of the cell electrode assembly 11 can be 1mm-4mm. In other examples, the lower surface of the heat-shrinkable layer 14 can also be flush with the first bottom surface 113 of the cell electrode assembly 11.

[0069] In some embodiments, the heat-shrinkable layer 14 includes a plurality of shrinkable portions, which are arranged around a first direction to form a first enclosing space 143, and the plurality of shrinkable portions are an integral structure. The integral structure of the heat-shrinkable layer 14 does not have splicing edges, overlapping seams, etc., which can ensure the uniform binding of the cell electrode assembly 11 when the heat-shrinkable layer 14 is heated and shrinks, and facilitates the processing and manufacturing of the heat-shrinkable layer 14.

[0070] Reference Figure 7 The plurality of contraction sections include two first contraction sections 141 opposite each other along a third direction and two second contraction sections 142 opposite each other along a second direction. The two first contraction sections 141 and the two second contraction sections 142 are integral structures, and the first enclosing space 143 is circumferentially closed. The junction between adjacent first contraction sections 141 and second contraction sections 142 can be a rounded corner structure.

[0071] In some embodiments, refer to Figure 8The heat shrinkable layer 14 includes a plurality of shrinkable sleeves 144, the battery cell electrode assembly 11 has an outer peripheral surface 111, the plurality of shrinkable sleeves 144 are sleeved on the outer peripheral surface 111, and the plurality of shrinkable sleeves 144 are arranged at intervals along a first direction.

[0072] The multiple shrinkable sleeves 144 are modular structures. The number of shrinkable sleeves 144 can be 2, 3, 4, 5, etc. Along the first direction, there may be a gap between adjacent shrinkable sleeves 144 or no gap. If there is a gap, the gap value is less than or equal to one-seventh of the height of the shrinkable sleeve 144, or less than or equal to 5 mm. Each shrinkable sleeve 144 forms a sub-enclosing space around the first direction, and multiple sub-enclosing spaces constitute the first enclosing space 143.

[0073] In this embodiment, different shrink sleeves 144 are located at different heights. During the heat shrinking process, they restrain the upper and lower edges and the center of the cell electrode assembly 11, which can ensure the overall restraint effect of the cell electrode assembly 11 and help the interface consistency of different areas of the electrode sheet.

[0074] In some embodiments, when there is a gap between two adjacent shrink sleeves 144, the heat insulation layer 13 may not be provided at the gap between the two adjacent shrink sleeves 144. That is, the heat insulation layer 13 is only located on the inner side of the shrink sleeve 144. In this way, it is not necessary to provide the heat insulation layer 13 on the entire outer peripheral surface 111 of the cell electrode assembly 11, which can reduce the weight and cost of the heat insulation layer 13 and improve the mass energy density of the battery.

[0075] In some embodiments, refer to Figure 8 The battery also includes multiple limiting structures 15, which are located on the inner side of the housing 20 or on the side of the heat insulation layer 13 facing the heat shrinkable layer 14. Along the first direction, the multiple limiting structures 15 are arranged at intervals, and the shrinkable sleeve 144 is located between two adjacent limiting structures 15.

[0076] The single limiting structure 15 may include only one limiting member 151, or it may include two limiting members 151 arranged opposite each other along the second direction, or it may include two limiting members 151 arranged opposite each other along a third direction. The limiting member 151 may be elongated or U-shaped.

[0077] The limiting member 151 can be fixed to the inside of the housing 20, for example, by adhesive to the inside of the housing 20. The limiting member 151 can also be fixed to the heat insulation layer 13, for example, by adhesive to the heat insulation layer 13. The limiting member 151 can be made of a rigid insulating material. By providing the limiting structure 15, the shrink sleeve 144 can be confined within the area between two adjacent limiting structures 15 during heat shrinking, thereby limiting the vertical position of the shrink sleeve 144.

[0078] In some embodiments, refer to Figures 9 to 12 With the height direction of the battery cell electrode assembly 11 as the first direction, the heat insulation layer 13 is arranged around the first direction to form a second enclosing space 133. The battery cell electrode assembly 11 has an outer peripheral surface 111, and at least 90% of the area of ​​the outer peripheral surface 111 is located within the second enclosing space 133. In one embodiment, at least 95% of the area of ​​the outer peripheral surface 111 is located within the second enclosing space 133. In this embodiment, the heat insulation layer 13 provides heat insulation around the battery cell electrode assembly 11, and the heat insulation effect is good.

[0079] In some embodiments, along the first direction, the edge of the heat insulation layer 13 extends beyond the edge of the heat shrinkable layer 14. In this case, the height of the heat insulation layer 13 is greater than the height of the heat shrinkable layer 14 to ensure the heat insulation effect.

[0080] Reference Figure 4 The upper surface of the heat insulation layer 13 is flush with the first top surface 112 of the cell electrode assembly 11. (Refer to...) Figure 6 The lower surface of the heat insulation layer 13 is higher than the first bottom surface 113 of the cell electrode assembly 11. Along the first direction, the distance between the lower surface of the heat insulation layer 13 and the first bottom surface 113 of the cell electrode assembly 11 can be 1mm-2mm. In other examples, the lower surface of the heat insulation layer 13 can also be flush with the first bottom surface 113 of the cell electrode assembly 11.

[0081] In some embodiments, the heat insulation layer 13 includes a plurality of heat insulation portions, which are arranged around a first direction to form a second enclosing space 133. The outer peripheral surface 111 of the battery cell electrode assembly 11 includes a plurality of side surfaces, each of which is opposite to a heat insulation portion. The plurality of heat insulation portions are either separate structures or integral structures. When the plurality of heat insulation portions are integral structures, it facilitates the processing and manufacturing of the heat insulation layer 13.

[0082] Reference Figures 9 to 12 The plurality of heat insulation portions include two first heat insulation portions 131 opposite each other along a third direction and two second heat insulation portions 132 opposite each other along a second direction. (Refer to...) Figure 9 and Figure 10 The two first heat-insulating parts 131 and the two second heat-insulating parts 132 are an integral structure, and the second enclosing space 133 is circumferentially closed. The junction between adjacent first heat-insulating parts 131 and second heat-insulating parts 132 can be a rounded corner structure. (Refer to...) Figure 11 and Figure 12 The two first heat insulation parts 131 and the two second heat insulation parts 132 are separate structures, and the two adjacent heat insulation parts are separated. The second enclosing space 133 is not closed in the circumference.

[0083] In some embodiments, the heat shrinkable layer 14 includes a heat shrinkable substrate and an embedded structure. The heat shrinkable substrate is disposed between the heat insulation layer 13 and the shell 20, and the embedded structure includes a plurality of negative expansion particles embedded in the heat shrinkable substrate.

[0084] The heat-shrinkable substrate is flexible and can be made of materials such as PVC (polyvinyl chloride), PP (polypropylene), or PE (polyethylene). The negative expansion particles are particles formed from a rigid negative expansion material, with a Mohs hardness greater than or equal to 1 and less than or equal to 10. The negative expansion material can include, but is not limited to, zirconium tungstate and silicon dioxide. Preferably, it is either zirconium tungstate or silicon dioxide. The size of the negative expansion particles can be in the micrometer range; for example, the size can be less than or equal to 2 micrometers. In this embodiment, compared to the flexible heat-shrinkable film, the heat-shrinkable layer 14 has a certain degree of hardness, which ensures the uniformity of shrinkage when heated.

[0085] In some embodiments, the heat shrink layer 14 comprises only a heat shrink substrate, in which case the entire heat shrink layer 14 can be a flexible heat shrink film.

[0086] In some embodiments, the heat-shrinkable layer 14 is made of a negative expansion material, in which case the heat-shrinkable layer 14 is a rigid sheet. The negative expansion material may include, but is not limited to, zirconium tungstate, silicon oxide, etc. Preferably, the negative expansion material is either zirconium tungstate or silicon oxide.

[0087] In some embodiments, refer to Figure 15 and Figure 16 The battery also includes a top cover assembly 30 connected to the top of the housing 20. The housing 20 and the top cover assembly 30 form a cavity, in which the cell body 10 is located, and electrolyte is also present. The top cover assembly 30 and the housing 20 can be connected by welding. During battery manufacturing, the cell body 10 is first placed inside the housing 20, and then the top cover assembly 30 is placed on top, connecting the top cover assembly 30 and the housing 20.

[0088] In some embodiments, the battery further includes a first encapsulation film covering all surfaces of the heat-shrinkable layer 14; the battery further includes a second encapsulation film covering all surfaces of the heat insulation layer 13.

[0089] The first and second encapsulation films are made of electrolyte-resistant materials, such as PP and PET (polyester). The first encapsulation film isolates the heat-shrinkable layer 14 from the electrolyte, preventing the material of the heat-shrinkable layer 14 from affecting the electrolyte and thus avoiding any impact on battery performance. Similarly, the second encapsulation film isolates the heat-insulating layer 13 from the electrolyte, preventing the material of the heat-insulating layer 13 from affecting the electrolyte and thus avoiding any impact on battery performance.

[0090] The first encapsulation film may include a first sub-film and a second sub-film. The first sub-film is located between the heat insulation layer 13 and the heat shrinkable layer 14, on the side of the heat shrinkable layer 14 opposite to the heat insulation layer 13. The first and second sub-films together cover all surfaces of the heat shrinkable layer 14. The first and second sub-films are connected, and the connection method may be heat sealing, adhesive bonding, etc.

[0091] The second encapsulation film may include a third sub-film and a fourth sub-film. The third sub-film is located between the cell electrode group 11 and the heat insulation layer 13, and the fourth sub-film is located between the heat insulation layer 13 and the heat shrinkable layer 14. The third and fourth sub-films together cover all surfaces of the heat insulation layer 13. The third and fourth sub-films are connected, and the connection method can be heat sealing, adhesive bonding, etc.

[0092] In some embodiments, the battery further includes a first adhesive layer disposed on the side of the heat insulation layer 13 near the cell electrode assembly 11, the first adhesive layer bonding the heat insulation layer 13 to the cell electrode assembly 11 or bonding the heat insulation layer 13 to the insulating film layer 12 on the outer peripheral surface 111 of the cell electrode assembly 11; the battery further includes a second adhesive layer disposed on the side of the heat shrinkable layer 14 near the heat insulation layer 13, the second adhesive layer bonding the heat shrinkable layer 14 to the heat insulation layer 13.

[0093] In this design, the cell electrode assembly 11 is covered with an insulating film layer 12. When the heat insulation layer 13 is disposed on the side of the insulating film layer 12 away from the cell electrode assembly 11, a first adhesive layer is located between the insulating film layer 12 and the heat insulation layer 13, bonding the heat insulation layer 13 to the insulating film layer 12. The presence of the first adhesive layer prevents the position of the heat insulation layer 13 from shifting along the first direction. A second adhesive layer is located between the heat insulation layer 13 and the heat-shrinkable layer 14, bonding the heat-shrinkable layer 14 to the heat insulation layer 13. The presence of the second adhesive layer prevents the position of the heat-shrinkable layer 14 from shifting along the first direction.

[0094] In other embodiments, the side of the heat shrinkable layer 14 closest to the heat insulation layer 13 may not have an adhesive layer.

[0095] In some embodiments, refer to Figure 13 and Figure 14 The battery also includes an insulating film layer 12, which covers at least the outer peripheral surface 111 of the cell electrode assembly 11, and a heat insulation layer 13 is disposed on the side of the insulating film layer 12 away from the cell electrode assembly 11.

[0096] The heat insulation layer 13 is located between the insulating film layer 12 and the heat-shrinkable layer 14. The cell electrode assembly 11 also has a first bottom surface 113, and the insulating film layer 12 is wrapped around the first bottom surface 113 of the cell electrode assembly 11. The material of the insulating film layer 12 includes, but is not limited to, PET, PP, PC (polycarbonate), etc. In this embodiment, the insulating film layer 12 can provide insulation protection for the cell electrode assembly 11, preventing the cell electrode assembly 11 from contacting metal parts and causing a short circuit.

[0097] It should be noted that when the insulation layer 13 is made of insulating material and is a flexible insulation layer, the insulating film layer 12 may not be provided, and the insulation protection function can be achieved through the insulation layer 13.

[0098] In some embodiments, the top cover assembly 30 includes a cover body 31 and a lower plastic part 32, wherein the cover body 31 is made of metal and the lower plastic part 32 is made of plastic. (See reference...) Figure 4 The upper surface of the insulating film layer 12 is higher than the first top surface 112 of the cell electrode assembly 11, as shown in the reference. Figure 17 The portion of the insulating film layer 12 that is higher than the first top surface 112 of the battery cell electrode group 11 is heat-fused and fixed to the lower plastic 32.

[0099] In some embodiments, the battery further includes a base plate located between the first bottom surface 113 of the cell electrode assembly 11 and the inner bottom wall of the housing 20. The base plate is made of an insulating material and supports the cell electrode assembly 11 covered with an insulating film layer 12, preventing the insulating film layer 12 covering the cell electrode assembly 11 from directly contacting the inner bottom wall of the housing 20.

[0100] As an example, the battery cell body 10 includes a cell electrode assembly 11, an insulating film layer 12, a heat insulation layer 13, and a heat shrinkable layer 14. The insulating film layer 12 is bonded to the heat insulation layer 13 via a first adhesive layer. Multiple heat insulation portions in the heat insulation layer 13 are integrally formed, and multiple shrinkable portions in the heat shrinkable layer 14 are integrally formed. During the battery formation stage, the four walls of the battery are heated. After the battery formation is completed, it is observed that the battery's shape does not show any expansion or deformation, and there is no lithium plating on the electrodes. After the thermal safety test of the battery is completed, it is observed that the casing 20 does not melt.

[0101] As another example, the battery cell body 10 includes a cell electrode assembly 11, an insulating film layer 12, a heat insulation layer 13, and a heat shrinkable layer 14. The insulating film layer 12 is bonded to the heat insulation layer 13 via a first adhesive layer. Multiple heat insulation sections in the heat insulation layer 13 are separate structures, while multiple shrinkable sections in the heat shrinkable layer 14 are an integral structure. During the battery formation stage, the four walls of the battery are heated. After the battery formation is completed, it is observed that the battery's shape does not show any expansion or deformation, and there is no lithium plating on the electrodes. After the thermal safety test of the battery is completed, it is observed that the casing 20 does not melt.

[0102] As another example, the battery cell body 10 includes a cell electrode assembly 11, an insulating film layer 12, a heat insulation layer 13, and a heat shrinkable layer 14. No first adhesive layer is provided between the insulating film layer 12 and the heat insulation layer 13. Multiple heat insulation portions in the heat insulation layer 13 are integrally formed, and multiple shrinkable portions in the heat shrinkable layer 14 are integrally formed. During the battery formation stage, the four walls of the battery are heated. After the battery formation is completed, it is observed that the battery's shape does not show any expansion or deformation, and there is no lithium plating on the electrodes. After the thermal safety test of the battery is completed, it is observed that the casing 20 does not melt.

[0103] Secondly, embodiments of this application propose a battery system including a heating element and the battery provided in the first aspect. The heating element is disposed on the outside of the battery and contacts the casing 20 in the battery. The heating element is used to heat the battery.

[0104] The heating element may include four electric heating plates, which are in contact with the four sides of the housing 20. During the battery formation stage, the four electric heating plates are in contact with the four sides of the housing 20 to heat the four walls of the battery. When the battery is heated, the heat shrink layer 14 shrinks and binds the cell electrode assembly 11.

[0105] This application embodiment may also provide a battery pack, including the battery provided in the first aspect.

[0106] Battery packs are used in electrical devices. These devices can include laptops, pen-and-paper computers, mobile computers, e-book players, portable telephones, portable fax machines, portable copiers, portable printers, stereo headphones, video recorders, LCD TVs, portable cleaners, portable CD players, mini CDs, transceivers, electronic notebooks, calculators, memory cards, portable recorders, radios, backup power supplies, motors, automobiles, motorcycles, electric bicycles, bicycles, ships, spacecraft, lighting fixtures, toys, game consoles, clocks, power tools, flashlights, cameras, large household batteries, and lithium-ion capacitors, among others.

[0107] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0108] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. A battery, characterized in that, It includes a battery cell electrode assembly (11), a heat insulation layer (13), a heat shrinkable layer (14), and a housing (20); The battery cell electrode assembly (11) is disposed inside the housing (20), the heat shrinkable layer (14) covers the outside of the battery cell electrode assembly (11), the heat insulation layer (13) is disposed between the battery cell electrode assembly (11) and the heat shrinkable layer (14), and the heat shrinkable layer (14) is used to shrink under heat to bind the battery cell electrode assembly (11).

2. The battery according to claim 1, characterized in that, With the height direction of the battery cell electrode group (11) as the first direction, the heat shrinkable layer (14) is arranged around the first direction to form a first enclosing space (143), and the heat insulation layer (13) and the battery cell electrode group (11) are both disposed in the first enclosing space (143); The cell electrode assembly (11) has an outer peripheral surface (111) of at least 90% of the area of ​​the outer peripheral surface (111) located within the first enclosing space (143), or, along the first direction, the edge of the heat-shrinkable layer (14) extends beyond the edge of the electrode sheet in the cell electrode assembly (11).

3. The battery according to claim 2, characterized in that, The heat-shrinkable layer (14) includes a plurality of shrinkable portions, which are arranged around the first direction to form the first enclosing space (143), and the plurality of shrinkable portions are an integral structure.

4. The battery according to claim 1, characterized in that, The heat shrinkable layer (14) includes a plurality of shrinkable sleeves (144), the battery cell electrode group (11) has an outer peripheral surface (111), the plurality of shrinkable sleeves (144) are sleeved on the outer peripheral surface (111), and the plurality of shrinkable sleeves (144) are spaced apart along a first direction.

5. The battery according to claim 4, characterized in that, The battery also includes a plurality of limiting structures (15), which are located on the inner side of the housing (20) or on the side of the heat insulation layer (13) facing the heat shrinkable layer (14). Along the first direction, the plurality of limiting structures (15) are arranged at intervals, and the shrinkable sleeve (144) is located between two adjacent limiting structures (15).

6. The battery according to claim 1, characterized in that, With the height direction of the battery cell electrode group (11) as the first direction, the heat insulation layer (13) is arranged around the first direction to form a second enclosing space (133); The cell electrode assembly (11) has an outer peripheral surface (111) of at least 90% of the area of ​​the outer peripheral surface (111) located within the second enclosing space (133), or, along the first direction, the edge of the heat insulation layer (13) extends beyond the edge of the heat shrinkable layer (14).

7. The battery according to claim 6, characterized in that, The heat insulation layer (13) includes a plurality of heat insulation portions, which are arranged around the first direction to form the second enclosing space (133). The outer peripheral surface (111) of the battery cell electrode assembly (11) includes a plurality of side surfaces, each of which is opposite to one of the heat insulation portions. The multiple heat insulation components are either separate structures or they are an integral structure.

8. The battery according to any one of claims 1 to 7, characterized in that, The heat shrinkable layer (14) includes a heat shrinkable substrate and an embedded structure. The heat shrinkable substrate is disposed between the heat insulation layer (13) and the shell (20). The embedded structure includes a plurality of negative expansion particles, which are embedded in the heat shrinkable substrate.

9. The battery according to any one of claims 1 to 7, characterized in that, Any of the following conditions must be met: A. The battery further includes a first encapsulation film, which covers all surfaces of the heat-shrinkable layer (14); B. The battery further includes a second encapsulation film, which covers all surfaces of the heat insulation layer (13); C. The battery further includes an insulating film layer (12), the insulating film layer (12) covering at least the outer peripheral surface (111) of the cell electrode assembly (11), and the heat insulation layer (13) is disposed on the side of the insulating film layer (12) away from the cell electrode assembly (11); D. The battery further includes a first adhesive layer, which is disposed on the side of the heat insulation layer (13) near the cell electrode assembly (11). The first adhesive layer bonds the heat insulation layer (13) to the cell electrode assembly (11) or bonds the heat insulation layer (13) to the insulating film layer (12) on the outer peripheral surface (111) of the cell electrode assembly (11). E. The battery further includes a second adhesive layer, which is disposed on the side of the heat shrinkable layer (14) near the heat insulation layer (13), and the second adhesive layer bonds the heat shrinkable layer (14) and the heat insulation layer (13).

10. A battery system, characterized in that, Includes a heating element and a battery as described in any one of claims 1-9, wherein the heating element is disposed on the outside of the battery and in contact with the casing (20) in the battery, and the heating element is used to heat the battery.

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