Battery cell and battery

Abstract

The utility model discloses a battery cell and a battery. The battery cell comprises a positive plate, a negative plate and a diaphragm, the positive plate comprises a positive current collector, a plurality of coating regions and a plurality of non-coating regions, the plurality of coating regions are formed on the surface of the positive current collector, each coating region comprises a positive active material layer, the plurality of non-coating regions are formed on the surface of the positive current collector, each non-coating region comprises an insulating layer, and the insulating layer is formed on the surface of the positive current collector. The plurality of coating areas and the plurality of non-coating areas are sequentially connected and alternately arranged, and the insulating layer is connected between two adjacent positive electrode active material layers. The positive plate is bent to form a stacked structure comprising a plurality of layers, the diaphragms are continuously bent corresponding to the positive plate and are compounded on the two sides of the positive plate, and the negative plate comprises a monolithic structure which is clamped between two adjacent layers and is positioned on one side, far away from the positive plate, of each diaphragm. The battery cell provided by the utility model can improve the comprehensive performance and safety of the battery.

Description

Technical Field

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

[0002] In recent years, batteries with a novel stacked structure formed by continuously bending and stacking long strip positive electrode sheets have developed rapidly. These batteries can achieve excellent self-heating function by arranging separators and negative electrode sheets on both sides of the positive electrode sheet, so that the battery can be quickly heated to the appropriate operating temperature range in low-temperature environments.

[0003] To ensure the negative electrode covers the positive electrode and prevent safety accidents such as lithium plating, the above-mentioned battery needs to form an empty foil area at the bending point of the positive electrode. That is, the active material on the positive electrode corresponding to the bending point needs to be removed. After the empty foil area is formed, the structural strength of the bending point on the positive electrode changes, and the connection and force relationship between the bending point and other parts of the positive electrode also changes. This can easily cause deformation, powder shedding and side reactions of the positive electrode, thereby causing battery performance imbalance. Summary of the Invention

[0004] This application provides a battery cell and a battery with good safety performance.

[0005] The first aspect of this application provides a battery cell, comprising: a positive electrode, a negative electrode, and a separator.

[0006] The positive electrode includes:

[0007] Positive current collector;

[0008] Multiple coating areas are formed on the surface of the positive electrode current collector, and the coating areas include a positive electrode active material layer;

[0009] And multiple uncoated areas are formed on the surface of the positive electrode current collector, the uncoated areas including an insulating layer.

[0010] In this configuration, multiple coated areas and multiple uncoated areas are sequentially connected and alternately arranged, and the insulating layer is connected between two adjacent positive electrode active material layers.

[0011] The positive current collector includes a first surface and a second surface opposite to each other. The coated area includes a first coated area formed on the first surface and a second coated area formed on the second surface. The uncoated area includes a first uncoated area formed on the first surface and a second uncoated area formed on the second surface. The insulating layer includes a first insulating layer formed on the first uncoated area and a second insulating layer formed on the second uncoated area.

[0012] The positive electrode sheet is bent to form a stacked structure comprising multiple layers, with a bend between two adjacent layers, the bend corresponding to the uncoated area of ​​the current collector.

[0013] The diaphragm is continuously bent and bonded to both sides of the positive electrode sheet;

[0014] The negative electrode includes a monolithic structure sandwiched between two adjacent layers and located on the side of the separator away from the positive electrode.

[0015] According to the battery cell described in the first aspect of this application, since the coated and uncoated areas on the positive electrode sheet are sequentially connected and alternately arranged, the positive active material layer and the insulating layer on the positive current collector can be sequentially connected and alternately appear. For the positive electrode sheet as a whole, the positive electrode sheet still has a highly integral structure with uniform internal stress distribution and high structural strength. When the positive electrode sheet is continuously bent, each layer and the bends connecting each layer are formed. The bends correspond to the uncoated areas of the current collector, where there is no positive active material layer, which is beneficial for the negative electrode sheet to cover the positive electrode sheet, thereby preventing safety issues such as lithium plating. Moreover, the bends are formed by the insulating layer and the corresponding positive current collector, possessing sufficient structural strength to prevent deformation, powder shedding, and side reactions of empty aluminum foil at the bends. Since the separator is continuously bent and connected to both sides of the positive electrode sheet, the negative electrode sheet includes a single negative electrode piece sandwiched between two adjacent layers and located on the side of the separator away from the positive electrode sheet. The coordination between the positive electrode, negative electrode, and separator, combined with the arrangement of the positive electrode active material layer and insulating layer on the positive electrode, ensures that the battery cell has sufficient structural strength and integrity after continuous bending of the positive electrode. This also provides sufficient structural strength during bending, thereby improving the overall performance and safety of the battery.

[0016] In one possible implementation, the thickness of the insulating layer is h1, where h1 satisfies: 4μm≤h1≤60μm.

[0017] In one possible implementation, the average thickness of the insulating layer is h2, and the average thickness of the positive current collector is h3, wherein h2 and h3 satisfy the following relationship:

[0018] 0.26h3≤h2≤4h3, 4μm≤h2≤60μm, 5μm≤h3≤20μm.

[0019] In one possible implementation, the average thickness of the positive electrode active material layer is h4, where h2 and h4 satisfy the following relationship:

[0020] 0.33h4≤h2≤1.5h4, 35μm≤h4≤80μm.

[0021] In one possible implementation, the insulating layer comprises insulating particles, and the porosity of the insulating layer is S, wherein S satisfies: 10% ≤ S ≤ 70%.

[0022] In one possible implementation, the D of the insulating layer 50 Satisfy: D 50 =40μm~90μm, the D of the insulating layer 99 Satisfy: D 99 =60μm~120μm.

[0023] In one possible implementation, the uncoated area includes two sub-regions extending in the width direction of the positive electrode, the boundary line between the two sub-regions extending in the width direction of the positive electrode, and the dimension of the sub-region in the length direction of the electrode is L1, wherein L1 satisfies: 0.1mm≤L1≤1.5mm.

[0024] In one possible implementation, the insulating layer is formed on at least one side of the positive current collector, and the thickness of the insulating layer gradually increases in the direction from one end near the positive active material layer to the boundary line.

[0025] In one possible implementation, along the length of the positive electrode sheet, the thickness of the first insulating layer alternates between gradually increasing and gradually decreasing from one end near the positive active material layer to the boundary line, and the thickness of the second insulating layer alternates between gradually decreasing and gradually increasing from one end near the positive active material layer to the boundary line. The projections of the first and second insulating layers in the thickness direction of the positive electrode sheet overlap. When the thickness of the first insulating layer gradually increases from one end near the positive active material layer to the boundary line, the thickness of the second insulating layer at the corresponding position in the thickness direction of the positive electrode sheet gradually decreases from one end near the positive active material layer to the boundary line.

[0026] In one possible implementation, the surfaces of the first and second insulating layers away from the positive current collector are curved, wavy, stepped, or steeply sloped.

[0027] In one possible implementation, the width ratio of the first insulating layer to the width ratio of the second insulating layer along the length of the positive electrode is P, wherein P satisfies: 0.33 ≤ P ≤ 3.

[0028] In one possible implementation, a single-sided coating region is formed at the end of the positive electrode sheet along its length direction, the single-sided coating region including a positive electrode active material layer, the single-sided coating region being formed on one or both sides of the positive electrode sheet.

[0029] In one possible implementation, a first edge insulating layer is provided between the edge of the positive electrode active material layer on the single-sided coating area and the edge of the positive electrode current collector, the width of the first edge insulating layer being S1. A second edge insulating layer is provided on the positive electrode current collector, the second edge insulating layer being located on the surface opposite to the single-sided coating area and adjacent to the positive electrode active material layer, the width of the second edge insulating layer being S2. S1 and S2 satisfy: 0.1mm≤S1≤0.5mm, 0.1mm≤S2≤0.5mm.

[0030] In one possible implementation, the insulating layer comprises one or more of AL2O3, α-alumina, γ-AlOOH, CeO2, MgAL2O4, ZrO, TiO2, and SiO2.

[0031] A second aspect of this application provides a battery comprising the cell described in the first aspect.

[0032] According to the battery described in the second aspect of this application, through the cooperation between the positive electrode sheet, the negative electrode sheet, and the separator, combined with the setting of the positive electrode active material layer and the insulating layer on the positive electrode sheet, the positive electrode sheet has sufficient structural strength and integrity after continuous bending, and the bending also has sufficient structural strength, which can improve the overall performance of the battery and improve the safety of the battery. Moreover, since the positive electrode sheet is an integral structure, the heating efficiency is improved when using cell self-heating technology.

[0033] In one possible implementation, the negative electrode comprises a monolithic structure, and the number of negative electrodes is one less than the number of layers.

[0034] In one possible implementation, the negative electrode further includes a dual-plate structure, which is formed by connecting two consecutive single-plate structures, and the connection portion forms a negative electrode bend, which is correspondingly arranged with respect to the bend and located on the side of the bend away from the positive electrode. Attached Figure Description

[0035] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 A disassembly schematic diagram of a battery according to an embodiment of this application is shown;

[0037] Figure 2 A schematic diagram of the structure of a battery according to an embodiment of this application is shown;

[0038] Figure 3 A disassembly schematic diagram of another battery provided according to an embodiment of this application is shown;

[0039] Figure 4 A schematic diagram of another battery structure provided according to an embodiment of this application is shown;

[0040] Figure 5 A first surface view of a positive electrode sheet provided according to an embodiment of this application is shown;

[0041] Figure 6 A second surface view of a positive electrode sheet provided according to an embodiment of this application is shown;

[0042] Figure 7 A schematic diagram of an insulating layer provided according to an embodiment of this application is shown;

[0043] Figure 8 A partially enlarged view of a positive electrode sheet provided according to an embodiment of this application is shown;

[0044] Figure 9 A schematic diagram of an insulating layer provided according to an embodiment of this application is shown;

[0045] Figure 10 A schematic diagram of another insulating layer provided according to an embodiment of this application is shown;

[0046] Figure 11 A schematic diagram of the structure of yet another insulating layer provided according to an embodiment of this application is shown;

[0047] Figure 12 A schematic diagram of the structure of another insulating layer provided according to an embodiment of this application is shown;

[0048] Figure 13 A plan view of a negative electrode sheet provided according to a second type embodiment of this application is shown;

[0049] Figure 14 A first surface view of a positive electrode sheet provided according to a second type embodiment of this application is shown;

[0050] Figure 15 A second surface view of a positive electrode sheet provided according to a second type embodiment of this application is shown.

[0051] Figure label:

[0052] 100-Positive electrode sheet; 110-Positive electrode current collector; 120-Positive electrode active material layer; 130-Insulating layer; 111-First surface; 112-Second surface; 113-Single-sided coated area; 114-First edge insulating layer; 115-Second edge insulating layer; 121-First positive electrode active material layer; 122-Second positive electrode active material layer; 131-First insulating layer; 132-Second insulating layer; 133-Curved section; 134-Wave section; 135-Stepped section; 136-Steep slope section; 137-High point; 101-Level; 102-Bend; 103-Coated area; 104-Uncoated area; 1011-First level; 1012-Second level; 1031-First coated area; 1032-Second coated area; 1041-First uncoated area; 1042-Second uncoated area; 1043-Boundary line;

[0053] 200-diaphragm;

[0054] 300 - Negative electrode sheet; 301 - Monolithic structure; 302 - Dual-layer structure; 310 - Negative electrode active material layer; 320 - Negative electrode bend;

[0055] 400-Soft electrode;

[0056] 10-battery. Detailed Implementation

[0057] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0058] The operating temperature range of a battery has a crucial impact on its performance. A reasonable operating temperature range can result in better cycle life, charging rate, and safety. Different temperature regulation methods can be used in different application scenarios.

[0059] When batteries are used as power batteries in vehicles, they need to have a high charging rate to meet the current usage requirements of vehicles. During high-rate charge-discharge cycles, batteries are prone to generating high temperatures. In this case, a thermal management device, such as a cooling plate, can be used to dissipate heat. Of course, for vehicles, when the journey is long, or when driving at night or starting at night, the battery will also be affected by low temperatures. To ensure the normal performance of the battery and the normal use of the vehicle, the battery can generally be heated externally or internally. External heating can be achieved using PTC materials or heating films, while internal heating can directly drive the electrode plates to generate heat.

[0060] Due to material limitations and other factors, it is difficult to generate enough heat by heating the negative electrode to maintain the battery's transition from a low temperature to a suitable temperature range. Therefore, related technologies typically employ heating the positive electrode to achieve the battery's self-heating function.

[0061] In recent years, batteries with novel stacked structures formed by continuously bending and stacking long strip positive electrode sheets have developed rapidly. The positive electrode sheet in these batteries is an integral and continuous sheet structure. These batteries can achieve excellent self-heating function by arranging a separator and a negative electrode sheet on both sides of the positive electrode sheet, so that the battery can be quickly heated to the appropriate operating temperature range in low-temperature environments.

[0062] For the batteries with the novel stacked structure, in order to ensure that the negative electrode covers the positive electrode and avoid safety accidents such as lithium plating, the batteries need to form empty foil areas at the bending points of the positive electrode. That is, the active material on the positive electrode corresponding to the bending point needs to be removed. After the empty foil area is formed, the structural strength of the bending point on the positive electrode changes, and the connection and force relationship between the bending point and other parts of the positive electrode also changes, which can easily cause the performance of the positive electrode to become unbalanced.

[0063] This can be understood as follows: because a void area is formed at the bend, the thickness of this void area is reduced compared to other parts of the positive electrode sheet, resulting in a decrease in structural strength at the bend. Consequently, the positive electrode sheet is prone to wrinkling, warping, and other deformation problems at this bend. Furthermore, the paste layer formed by the positive electrode active material is interrupted at the bend, disrupting the integrity of the paste layer. The paste layer will have two ends corresponding to the bend, and due to insufficient strength support, these ends will experience powder shedding. In addition, this powder shedding can easily allow powder to come into contact with the void area, exposing the positive electrode current collector material, such as aluminum. Since the powder usually contains lithium ions, this can easily induce side reactions between materials, damaging the overall performance of the battery.

[0064] As described above, it is understandable that deformation, powder shedding, and side reactions can all cause performance imbalances in the positive electrode, thereby affecting the overall performance of the battery or reducing its safety.

[0065] Based on the above situation and problems, this application provides a battery cell that optimizes the positive electrode structure. By adding a reinforcing structure at the bending point to improve the structural strength of the bending and the overall integrity of the positive electrode, and in conjunction with the separator and negative electrode, the overall performance of the battery and the safety of the battery can be improved while ensuring that the battery has excellent self-heating function.

[0066] To achieve the above objectives, the positive electrode sheet is a long strip-shaped sheet structure. The positive electrode sheet has a coated area and an uncoated area. The coated area includes a positive electrode active material layer, and the uncoated area includes an insulating layer. The insulating layer serves as the aforementioned reinforcing structure. The insulating layer and the positive electrode active material layer have sufficient connection strength, so that after the positive electrode sheet is continuously bent, the bend formed by the uncoated area has sufficient structural strength, which can avoid deformation problems and prevent powder shedding. The integrity of the positive electrode sheet is well maintained, and the occurrence of side reactions can be avoided.

[0067] In order to optimize the structure of the battery in this application embodiment, the negative electrode and separator can also be optimized. This optimization design is mainly for the matching design of the positive electrode. The matching design scheme of the negative electrode will be fully described in the following embodiments.

[0068] The battery in this embodiment can be used in electrical devices such as vehicles, mobile phones, tablets, laptops, electric balance scooters, and home appliances.

[0069] Figure 1 A disassembly schematic diagram of a battery according to an embodiment of this application is shown; Figure 2 A schematic diagram of the structure of a battery according to an embodiment of this application is shown; Figure 3 A disassembly schematic diagram of another battery provided according to an embodiment of this application is shown; Figure 4 A schematic diagram of the structure of another battery provided according to an embodiment of this application is shown.

[0070] In the embodiments of this application, please refer to Figures 1 to 4 The battery 10 may include a positive electrode 100, a separator 200, and a negative electrode 300.

[0071] The positive electrode 100 includes a positive current collector 110 (see reference). Figure 5The positive electrode active material layer 120 and the insulating layer 130 are disposed on the positive electrode current collector 110. The positive electrode active material layer 120 and the insulating layer 130 are connected and are disposed alternately.

[0072] The positive electrode active material layer 120 can be formed by coating the positive electrode active material onto the positive electrode current collector 110. The positive electrode current collector 110 can be made of aluminum foil or the like. The positive electrode active material can be a lithium-containing material, such as lithium cobalt oxide, lithium iron phosphate, ternary lithium, lithium carbonate, etc.

[0073] The positive electrode 100 is continuously bent to form a stacked structure comprising multiple layers 101, with bends 102 forming between adjacent layers 101. It can be understood that the positive electrode 100 is a sheet-like structure extending along its length; by continuously bending it, a continuous Z-shaped structure can be formed. Two adjacent portions connected to each bend 102 form two layers 101. For the overall structure of the positive electrode 100, refer to... Figure 2 or Figure 4 The number of bends 102 is usually one less than the number of levels, for example in... Figure 2 and Figure 4 In the example shown, the positive electrode 100 includes 10 layers and 9 bends.

[0074] In this embodiment, the positive electrode 100 is based on the alternating arrangement of its positive electrode active material layer 120 and insulating layer 130. The insulating layer 130 and the positive electrode active material layer 120 have sufficient connection strength, so that after the positive electrode 100 is continuously bent, the positive electrode 100 as a whole has sufficient structural strength and integrity. The bending 102 also has sufficient structural strength, which can improve the overall performance and safety of the positive electrode 100.

[0075] The separator 200 in the battery is positioned between the positive electrode 100 and the negative electrode 300. Its size typically needs to be larger than the positive electrode 100 and the negative electrode 300 so that the edges of the separator 200 can extend from the edges of the positive electrode 100 and the negative electrode 300, thus providing good insulation between them. The material of the separator 200 can be selected according to actual needs; for example, polyethylene or polypropylene can be used.

[0076] The separator 200 is continuously bent in response to the positive electrode 100. Typically, one separator 200 can be provided on each side of the positive electrode 100. Of course, in other embodiments, the number of separators 200 can also be varied. The number of separators 200 provided on both sides of the positive electrode 100 can be the same or different.

[0077] The continuous bending of the corresponding positive electrode 100 means that the separator 200 has the same structural shape as the positive electrode 100, so that the separator 200 can be attached to the surface of the positive electrode 100.

[0078] The negative electrode 300 is sandwiched between two adjacent layers 101 and located on the side of the separator 200 away from the positive electrode 100. The negative electrode 300 includes a negative current collector and a negative active material layer 310 disposed on the negative current collector. The negative current collector can be made of copper foil or the like, and the negative active material can be one or more of graphite, silicon carbide, silicon oxide, pure silicon, and alloy silicon.

[0079] It is understood that the main function of the negative electrode 300 in this application embodiment is to provide sufficient active intercalation sites for lithium ions on the positive electrode 100, so that lithium ions can be intercalated into or detached from the negative electrode 300. The negative electrode 300 is sandwiched between two adjacent layers 101 and can form a sufficient interaction area with the lithium ions on the positive electrode 100.

[0080] It is understandable that, in order to improve the energy density of the battery 10, the positive electrode 100 can be a double-sided positive electrode, that is, a positive active material layer 120 is provided on both surfaces of the positive electrode 100, and the negative electrode 300 can be a double-sided negative electrode, that is, a negative active material layer 310 is provided on both surfaces of the negative electrode 300.

[0081] It should be understood that the negative electrode 300 can be selected according to the setting of the positive active material layer 120 of the positive electrode 100. When the positive electrode 100 adopts a double-sided positive electrode, the negative electrode 300 adopts a double-sided negative electrode.

[0082] As can be understood from the following embodiments of the positive electrode 100, the positive electrode 100 may adopt a hybrid structure, with some parts being single-sided and some parts being double-sided. This can be understood in conjunction with the following embodiments.

[0083] In this embodiment of the application, the battery 10, through the cooperation between the positive electrode 100, the negative electrode 300 and the separator 200, combined with the setting of the positive active material layer 120 and the insulating layer 130 on the positive electrode 100, ensures that the positive electrode 100 has sufficient structural strength and integrity after continuous bending, and the bending 102 also has sufficient structural strength, which can improve the overall performance of the battery 10 and enhance the safety of the battery 10.

[0084] In some embodiments, please refer to Figure 2 The negative electrode 300 includes a monolithic structure 301, wherein the negative electrode 300 of the monolithic structure 301 represents a single individual, and the number of negative electrode 300 can be one less than the number of layers 101.

[0085] exist Figure 2 In the example shown, the positive electrode 100 is formed with 10 layers 101, and a negative electrode 300 with a monolithic structure 301 is disposed between each two adjacent layers 101, and the number of negative electrode 300 is 9.

[0086] In some embodiments, please refer to Figure 4 The negative electrode 300 also includes a dual-plate structure 302, which includes two consecutive single-plate structures 301. A negative electrode bend 320 is formed between the two single-plate structures 301. The negative electrode bend 320 is correspondingly arranged with the bend 102 and is located on the outside of the bend 102.

[0087] exist Figure 4 In the example shown, the positive electrode 100 has 10 layers 101, and the total number of negative electrodes 300 is 5, including 4 negative electrodes 300 with dual-layer structure 302 and 1 negative electrode 300 with single-layer structure 301. The combination of dual-layer structure 302 and single-layer structure 301 can make the negative electrode 300 adapt to each layer 101 of the positive electrode 100.

[0088] exist Figure 4 In the example described, it is known that the negative electrode 300 of the monolithic structure 301 is located on the lower side, and the negative electrode 300 of the dual-plate structure 302 is located on the upper side. It is understood that in other embodiments, the position of the negative electrode 300 of the monolithic structure 301 can be changed, for example, it can be located on the upper side or in the middle.

[0089] In other embodiments, the structure type of the negative electrode 300 can be flexibly changed. For example, the negative electrode 300 may also include a three-piece structure or a four-piece structure. By reasonably configuring the relationship between the layers 101 of these negative electrode 300 and the positive electrode 100, the corresponding settings of the negative electrode 300 and the positive electrode 100 can be realized.

[0090] It is understandable that in embodiments where the positive electrode 100 has different levels 101, for example, when the level 101 of the positive electrode 100 is an odd number such as 9, 11, or 13, the type of negative electrode 300 and the combination of different types of negative electrode 300 can be reasonably selected in order to provide sufficient active embedding sites for the positive electrode 100.

[0091] It should be noted that the number of layers 101 in the positive electrode 100 can be set according to requirements. The number of layers 101 in the positive electrode 100 can be selected from 2 to 200, with an areal density of 5 mg / cm³. 2 ~50mg / cm 2 Between these values, the thickness of the diaphragm 300 is between 4μm and 17μm.

[0092] In some embodiments, the insulating layer 130 on the uncoated area 104 of the surface of the positive current collector 110 corresponding to the negative electrode bend 320 is replaced by an active material layer.

[0093] In the following embodiments, the battery 10 will be described separately for a negative electrode 300 employing a single-piece structure 301 and a negative electrode 300 employing a combination of a single-piece structure 301 and a dual-piece structure 302. For ease of classification, the former belongs to the category of the first type of embodiments, which can be referred to. Figure 1 and Figure 2 The latter falls under the category of the second type of embodiment, and can be referred to. Figure 3 and Figure 4 .

[0094] Figure 5 A first surface view of a positive electrode sheet provided according to an embodiment of this application is shown; Figure 6 A second surface view of a positive electrode provided according to an embodiment of this application is shown.

[0095] In the first type of embodiment of this application, please refer to the reference. Figures 1 to 6 The positive electrode 100 includes a positive current collector 110, multiple coated areas 103 and multiple uncoated areas 104.

[0096] The positive current collector 110 has been described in the previous text and will not be repeated here.

[0097] Both the coated area 103 and the uncoated area 104 are formed on the surface of the positive electrode current collector 110. They can be formed on one surface or both surfaces of the positive electrode current collector 110. The coated area 103 includes a positive electrode active material layer 120, which has been described in detail above. The uncoated area 104 includes an insulating layer 130 that is different from the positive electrode active material layer 120. The main function of the insulating layer 130 is to form a connection with the positive electrode active material layer 120, so that the negative electrode sheet 300 can cover the positive electrode sheet 100. When the positive electrode sheet 100 is bent at the position of the insulating layer 130, it can ensure that the positive electrode sheet 100 has sufficient structural strength and integrity as a whole, and the bending also has sufficient structural strength.

[0098] Multiple coated areas 103 and multiple uncoated areas 104 are sequentially connected and alternately arranged, with an insulating layer 130 connected between two adjacent positive electrode active material layers 120. The alternating arrangement of multiple coated areas 103 and multiple uncoated areas 104 achieves the alternating arrangement of the positive electrode active material layer 120 and the insulating layer 130. This arrangement provides a structural basis for the continuous bending of the positive electrode sheet 100, so that after the positive electrode sheet 100 is continuously bent, each positive electrode active material layer 120 and the corresponding positive electrode current collector 110 can form a layer 101 of the positive electrode sheet 100, and each insulating layer 130 and the corresponding positive electrode current collector 110 can form a bend 102 of the positive electrode sheet 100, thereby improving the integrity and overall strength of the positive electrode sheet 100.

[0099] In this embodiment, the positive electrode 100, due to the sequential connection and alternating arrangement of the coated area 103 and the uncoated area 104, allows the positive electrode active material layer 120 and the insulating layer 130 on the positive electrode current collector 110 to be sequentially connected and alternately present. For the positive electrode 100 as a whole, it remains a highly integrated structure with uniform internal stress distribution and high structural strength. When the positive electrode 100 is continuously bent, various layers 101 and bends 102 connecting the layers 101 are formed. At these bends 102, the positive electrode active material layer 120 is not present. The negative electrode 300 covers the positive electrode 100, thus preventing safety issues such as lithium plating. As for the bend 102 on the positive electrode 100, since the bend 102 is formed by the insulating layer 130 and the corresponding positive current collector 110, the bend 102 also has sufficient structural strength to prevent deformation, powder shedding, and side reactions of the positive electrode 100 at the bend 102. The above-mentioned properties of the positive electrode 100 make the battery 10 formed with the positive electrode 100 not only have excellent self-heating function, but also excellent comprehensive performance and safety performance.

[0100] In accordance with the foregoing, in order to improve the energy density of the battery 10, the positive electrode 100 can be a double-sided positive electrode. To be compatible with the stacking structure of the positive electrode 100, the two exposed surfaces of the positive electrode 100 should be surfaces that are not coated with the positive active material layer 120. Based on this, the positive electrode 100 can be designed as follows.

[0101] Figure 7 A schematic diagram of the structure of an insulating layer 130 provided according to an embodiment of this application is shown.

[0102] Please refer to the reference. Figure 1 , Figure 2 , Figures 5 to 7The positive electrode current collector 110 includes a first surface 111 and a second surface 112 opposite to each other. The coating area 103 includes a first coating area 1031 formed on the first surface 111 and a second coating area 1032 formed on the second surface 112. The uncoated area 104 includes a first uncoated area 1041 formed on the first surface 111 and a second uncoated area 1042 formed on the second surface 112. The positive electrode active material layer 120 includes a first positive electrode active material layer 121 formed on the first coating area and a second positive electrode active material layer 122 formed on the second coating area 1042. The insulating layer 130 includes a first insulating layer 131 formed on the first uncoated area 1041 and a second insulating layer 132 formed on the second uncoated area 1042.

[0103] Therefore, by providing a first positive electrode active material layer 121 and a second positive electrode active material layer 122 on the first surface 111 and the second surface 112 of the positive electrode current collector 110 respectively, the energy density of the battery 10 can be improved. At the same time, by providing a first insulating layer 131 and a second insulating layer 132, the two sides of the positive electrode current collector 110 can be wrapped, which can improve the structural strength of the bending 102.

[0104] To facilitate understanding and simplify the description, Figure 2 Taking the indicated direction as an example and referring to other locations Figure 1 , Figures 5 to 6 The uppermost layer 101 in the positive electrode 100 is the first layer 1011, and the lowermost layer 101 in the positive electrode 100 is the second layer 1012. The upper surface of the first layer 1011 (one of the above-mentioned exposed surfaces), the lower surface of the second layer 1012 (one of the above-mentioned exposed surfaces), and the right-side surfaces of other layers 101 together form the first surface 111 of the positive electrode 100. The upper surface of the second layer 1012, the lower surface of the first layer 1011, and the left-side surfaces of other layers 101 together form the second surface 112 of the positive electrode 100.

[0105] In some embodiments, the width ratio of the first insulating layer 131 to the width ratio of the second insulating layer 132 is P, where P satisfies: 0.33 ≤ P ≤ 3.

[0106] Setting P according to the above dimensions can reasonably distribute the stress ratio on the inner and outer sides of the bending 102, preventing phenomena such as powder shedding while ensuring energy density. In specific design, P can be a range of 0.33, 0.5, 1, 1.5, 2, 2.5, 3, or any two of these. It can be understood that when the value of P is smaller, the first insulating layer 131 is more prone to powder shedding due to stress, which can expose the positive electrode current collector 110. When the value of P is too large, the first insulating layer 131 will occupy more space of the positive electrode current collector 110, which is not conducive to forming a high energy density battery 10. Setting P within the above-mentioned size range can balance the relationship between powder shedding and energy density.

[0107] In some embodiments, single-sided coating regions 113 are formed at both ends of the positive electrode 100 along its length direction. The single-sided coating regions 113 include a positive electrode active material layer 120 and are formed on a first surface 111 or a second surface 112.

[0108] As mentioned above, when the positive electrode 100 adopts a hybrid structure, some parts of the positive electrode 100 are double-sided positive electrode 100 and some parts of the positive electrode 100 are single-sided positive electrode 100. In order to fit the stacking structure, the above embodiment sets the end of the positive electrode 100 into a single-sided positive electrode 100 structure, which is beneficial to the encapsulation of the positive electrode 100 and can prevent the positive electrode 100 from short-circuiting.

[0109] Specifically, please refer to the reference. Figure 2 and Figures 5 to 6 The first layer 1011 and the second layer 1012 are designed to resemble a single-sided positive electrode sheet. For the first layer 1011, its lower surface has a positive electrode active material layer 120, and for the second layer 1012, its upper surface has a positive electrode active material layer 120.

[0110] It is understandable that the stacking structure of the positive electrode 100 will change when the number of layers 101 is different. For example, in Figure 2In the example shown, the number of layers 101 is even. The second layer 1012 extends from right to left from the bottom right bend 102. In this case, it can be understood that neither end of the first surface 111 of the positive electrode 100 has a positive active material layer 120, and both ends of the second surface 112 of the positive electrode 100 have a positive active material layer 120. When the number of layers 101 is odd, the second layer 1012 can extend from left to right from the bottom left bend 102. In this case, one end of the first surface 111 of the positive electrode 100 does not have a positive active material layer 120, while the other end has a positive active material layer 120. One end of the second surface 112 of the positive electrode 100 has a positive active material layer 120, while the other end does not. The distribution of the first surface 111 can be referenced. Figure 5 The distribution of the second surface 112 can be referenced. Figure 6 .

[0111] In some embodiments, please refer to Figure 5 and Figure 6 A first edge insulating layer 114 is provided between the edge of the positive electrode active material layer 120 on the single-sided coating area 113 and the edge of the positive electrode current collector 110. The width of the first edge insulating layer 114 is S1. A second edge insulating layer 115 is provided on the positive electrode current collector 110. The second edge insulating layer 115 is located on the surface opposite to the single-sided coating area and adjacent to the positive electrode active material layer. The width of the second edge insulating layer 115 is S2. S1 and S2 satisfy: 0.1mm≤S1≤0.5mm, 0.1mm≤S2≤0.5mm.

[0112] exist Figure 5 In the middle, the first edge insulating layer 114 is formed on the far right, corresponding to the upper surface of the second layer 1042 of the odd-numbered layers 101, and the second edge insulating layer 115 is formed on the left. Figure 6 In the middle, the first edge insulating layer 114 is formed on the far left, corresponding to the lower surface of the first layer 1011 of the odd-numbered layers 101, and the second edge insulating layer 115 is formed on the right. The arrangement of the first edge insulating layer 114 and the second edge layer 115 ensures that the negative electrode 300 covers the end of the positive electrode 100, thereby improving the energy density of the battery 10. In specific design, S1 and S2 can be the same or different, and their values ​​can be 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm or any combination thereof.

[0113] Figure 8 A partially enlarged view of a positive electrode sheet provided according to an embodiment of this application is shown; Figure 9A schematic diagram of an insulating layer provided according to an embodiment of this application is shown; Figure 10 A schematic diagram of another insulating layer provided according to an embodiment of this application is shown; Figure 11 A schematic diagram of the structure of yet another insulating layer provided according to an embodiment of this application is shown; Figure 12 A schematic diagram of the structure of another insulating layer provided according to an embodiment of this application is shown.

[0114] In some embodiments, please refer to Figure 8 The uncoated area 104 has a boundary line 1043, which divides the uncoated area 104 into two sub-regions. The two sub-regions have the same length in the longitudinal direction of the positive electrode 100, and the insulating layer 130 is symmetrically arranged about the boundary line 1043.

[0115] It is understandable that setting the insulating layer 130 symmetrical about the boundary line 1043 can make the bend 102 connecting the two adjacent layers 101 have higher strength and uniform strength distribution, which can further improve the integrity and structural strength of the positive electrode 100.

[0116] In some specific embodiments, please refer to Figure 8 The distance from the end of the insulating layer 130 adjacent to the positive electrode active material layer to the boundary line 1043 is L1, which satisfies: 0.1mm≤L1≤1.5mm.

[0117] Setting L1 according to the above dimensions can improve the energy density of battery 10 and ensure the coverage of positive electrode 100 by negative electrode 300. In specific design, L1 can be a range of 0.1mm, 0.5mm, 1mm, 1.5mm or any two of these. It can be understood that the smaller the value of L1, the shorter the length of insulating layer 130, making it difficult to ensure full coverage of positive electrode 100. Furthermore, as the value of L1 decreases, it becomes more difficult to achieve in terms of manufacturing process. When the value of L1 is too large, although full coverage can be achieved, it will affect the energy purpose of battery 10. Setting L1 within the above-mentioned size range can reduce the impact on energy density while achieving coverage of positive electrode 100 by negative electrode 300, and can also simplify the manufacturing process and control costs.

[0118] In other embodiments, the uncoated region 104 has a boundary line 1043 that divides the uncoated region 104 into two sub-regions. The two sub-regions are of the same length in the longitudinal direction of the positive electrode 100, and the insulating layer 130 is asymmetrically arranged about the boundary line 1043.

[0119] The asymmetrical arrangement here simplifies the production process of the positive electrode 100 and allows for a more flexible design direction. It enables the insulation layer 130 to be distributed on both sides of the boundary line 1043 according to the overall size of the positive electrode 100 and the different sizes of each layer 101.

[0120] In some embodiments, the insulating layer 130 is formed on at least one side of the positive current collector 110, and may be formed on the first surface 111 of the positive current collector 110, or on the second surface 112 of the positive current collector 110. Figure 7 and Figure 8 In the example shown, insulating layer 130 is formed on both sides of positive current collector 110.

[0121] As described above, the first insulating layer 131 is located on the outer side of the bend 102, and the second insulating layer 132 is located on the inner side of the bend 102. In some embodiments, please refer to... Figure 8 Along the length of the positive electrode 100, the thickness of a plurality of first insulating layers 131 located on the first surface of the positive electrode current collector alternates between gradually increasing from one end near the positive electrode active material layer 120 to the boundary line 1043 and gradually decreasing from one end near the positive electrode active material layer 120 to the boundary line 1043. The thickness of a plurality of second insulating layers 132 located on the second surface of the positive electrode current collector alternates between gradually decreasing from one end near the positive electrode active material layer 120 to the boundary line 1043 and gradually increasing from one end near the positive electrode active material layer 120 to the boundary line 1013. The projections of the first insulating layers 131 and the second insulating layers 132 in the thickness direction of the positive electrode 100 overlap. When the thickness of the first insulating layer 131 gradually increases from one end near the positive electrode active material layer 120 to the boundary line 1043, the thickness of the second insulating layer 132 at the corresponding position in the thickness direction of the positive electrode sheet 100 gradually decreases from one end near the positive electrode active material layer 120 to the boundary line 1043.

[0122] In the above embodiments, by controlling the thickness variation of the first insulating layer 131, the stretching caused by folding of the first insulating layer 131 can be reduced, and problems such as powder shedding and detachment of the first insulating layer 131 during bending can be avoided or reduced. By controlling the thickness variation of the second insulating layer 132, problems such as powder shedding and detachment of the second insulating layer 132 during bending can be avoided or reduced. When the thickness variations of several first and second insulating layers follow the above-mentioned pattern, it can be ensured that the thickness of the insulating layer inside and outside each bend is matched, making the formed Z-shaped battery cell more uniform in thickness and more stable in structure.

[0123] To achieve the aforementioned trend in thickness, the structure of the insulating layer 130 can be designed in various ways, for example, in Figure 9 In the example shown, the surfaces of the first insulating layer 131 and the second insulating layer 132 that are away from the positive current collector 110 are curved, and the curved surfaces tend to move towards or away from the positive current collector 110 as a whole; for example, in Figure 10 In the example shown, the surfaces of the first insulating layer 131 and the second insulating layer 132 that are away from the positive current collector 110 are wavy, and the wavy surfaces tend to move towards or away from the positive current collector 110 as a whole; for example, in Figure 11 In the example shown, the surfaces of the first insulating layer 131 and the second insulating layer 132 that are away from the positive current collector 110 are stepped, and these stepped surfaces tend to move towards or away from the positive current collector 110 as a whole; for example, in Figure 12 In the example shown, the surfaces of the first insulating layer 131 and the second insulating layer 132 that are away from the positive current collector 110 have steep slopes, which tend to move towards or away from the positive current collector 110 as a whole.

[0124] exist Figures 9 to 12 In the example shown, the curved surface includes multiple curved surface segments 133, each of which has a high point 137, and each high point 137 tends to move closer to or further away from the positive electrode current collector 110; the wavy surface includes multiple wavy segments 134, each of which has a high point 137, and each high point 137 tends to move closer to or further away from the positive electrode current collector 110; the stepped surface includes multiple stepped segments 135, each of which has a high point 137, and each high point 137 tends to move closer to or further away from the positive electrode current collector 110; the steep slope surface includes multiple steep slope segments 136, each of which has a high point 137, and each high point 137 tends to move closer to or further away from the positive electrode current collector 110.

[0125] It is understandable that the aforementioned changes in the thickness of the first insulating layer 131 and the second insulating layer 132 can be linear or nonlinear. When a nonlinear change is adopted, the change in thickness is not monotonically changing, but the overall trend of change is maintained.

[0126] In some embodiments, please refer to Figure 7 The thickness of the insulating layer 130 is h1, and h1 satisfies: 4μm≤h1≤60μm. For ease of demonstration, Figure 7 The insulating layer 130 has the same thickness along the length of the positive electrode 100. In actual electrodes, the thickness of the insulating layer may be uneven, but the thickness at any point is within the range of 4μm≤h1≤60μm.

[0127] Here, insulating layer 130 refers to either the first insulating layer 131 or the second insulating layer 132. Setting h1 according to the above dimensions can reasonably configure the thickness relationship between insulating layer 130 and positive current collector 110, balance the intensity distribution of the two, and improve the battery capacity and cycle life. In specific design, h1 can be 4μm, 10μm, 20μm, 30μm, 40μm, 50μm, 60μm, or any combination thereof. It is understandable that when the thickness of insulating layer 130 is less than 4μm, it will result in too low areal density of insulating layer 130, too many foil leakage positions at insulating layer 130, and too large total foil leakage area, thus failing to ensure that insulating layer 130 completely covers bending 102. When the thickness is greater than 60μm, the areal density of the insulating layer 130 will be too high. This will increase the weight or volume load of the positive current collector 110 at the bend 102, causing powder shedding at the bend 102. As a result, it is impossible to ensure that the insulating layer 130 completely covers the bend 102, or powder may remain on the nearby positive active material layer 120. This will directly reduce the capacity of the battery 10 and interfere with the consistency of ΔSOC (or SOCdQ of the differential capacity-SOC curve) in the length and width directions during electrode cycling, thereby weakening the cycle life of the battery 10.

[0128] In other embodiments, the thickness of the insulating layer 130 along the length of the positive electrode 100 has a certain variation trend. For example, the insulating layer 130 is set with the aforementioned variation trend, the average thickness of the insulating layer 130 is h2, the average thickness of the positive electrode current collector 110 is h3, and h2 and h3 satisfy the following relationship: 0.26h3≤h2≤4h3, 4μm≤h2≤60μm, 5μm≤h3≤20μm.

[0129] Here, insulating layer 130 refers to either the first insulating layer 131 or the second insulating layer 132. Setting h2 and h3 according to the above dimensions can reasonably configure the thickness relationship between insulating layer 130 and positive current collector 110, balancing their strength distribution. It is understandable that if insulating layer 130 is too thin and positive current collector 110 is too thick, the areal density of insulating layer 130 will be too low, resulting in too many foil leakage points and an excessively large total foil leakage area, thus failing to ensure that insulating layer 130 completely covers bend 102. If insulating layer 130 is too thick and positive current collector 110 is too thin, the positive current collector 110 at the location of bend 102 will be unable to withstand the compressive stress of insulating layer 130, leading to problems such as cracking, breakage, and wrinkling of positive current collector 110.

[0130] In some specific embodiments, the average thickness of the positive electrode active material layer 120 is h4, and h2 and h4 satisfy the following relationship: 0.33h4≤h2≤1.5h4, 35μm≤h4≤80μm.

[0131] In this invention, the thickness h1 of the insulation layer is measured by the following method: a high-precision digital micrometer (Mitutoyo / 293-100, Japan) is used to measure the thickness of the current collector body and the current collector after the insulation layer is coated, and the difference between the two thicknesses is the thickness of the insulation layer.

[0132] The average thickness h2 of the insulation layer can be measured by the following method: observe the complete cross-section of the insulation layer in the uncoated area along the length of the electrode under a scanning electron microscope, take 10 points at equal intervals along the length of the electrode in this area, measure the thickness of the insulation layer, and take the arithmetic mean as the average thickness of the insulation layer.

[0133] The average thickness h3 of the positive electrode current collector can be measured by the following method: the thickness of the current collector body is measured using a high-precision digital micrometer (Mitutoyo / 293-100, Japan), with an interval of 2mm-3mm between adjacent test points, and the arithmetic mean of 10 measurement results is taken as the average thickness of the positive electrode current collector.

[0134] The average thickness h4 of the positive electrode active material layer can be measured by the following method: a high-precision digital micrometer (Mitutoyo / 293-100, Japan) is used to measure the thickness of the current collector body and the current collector after coating with the positive electrode active material layer. The difference between the two thicknesses is the thickness of the positive electrode active material layer. The adjacent test points are spaced 2mm-3mm apart, and the arithmetic mean of 10 measurement results is taken as the average thickness of the positive electrode active material layer.

[0135] Setting h2 and h4 according to the above dimensions allows for a reasonable configuration of the thickness relationship between the insulating layer 130 and the positive electrode active material layer 120. If the insulating layer 130 is too thin and the positive electrode active material layer 120 is too thick, the positive electrode active material layer 120 will tend to accumulate on the insulating layer 130, making the interface between the positive electrode active material layer 120 and the insulating layer 130 more prone to powder shedding, thus causing problems such as internal short circuits in the battery 10. If the insulating layer 130 is too thick and the positive electrode active material layer 120 is too thin, the edge thickness in the width direction of the battery 10 will be much greater than the thickness of the battery body, making the formation process of the battery 10 difficult to complete and easily resulting in a loss of energy density.

[0136] In some embodiments, the insulating layer 130 comprises insulating particles, and the porosity of the insulating layer 130 is S, where S satisfies: 10% ≤ S ≤ 70%.

[0137] The insulating layer 130 may include one or more of AL2O3, α-alumina, γ-AlOOH, CeO2, MgAL2O4, ZrO, TiO2, and SiO2. The above materials are designed into insulating particles and can be coated to form the insulating layer 130.

[0138] Setting the porosity of the insulating layer 130 within the aforementioned range ensures the wetting effect of the electrolyte and improves the cycle performance of the battery 10. Understandably, if the porosity of the first insulating layer 131 is too small, it will affect the electrolyte wetting process, resulting in poor electrolyte wettability on the outside of the bend 102. This reduces the rate at which the electrolyte migrates into the internal electrode of the battery 10, causing the wetting rate from the top and bottom of the battery 10 to be much higher than from the sides, leading to uneven wetting of the electrolyte on the electrode and consequently affecting the later-stage cycle performance of the cell. If the porosity of the second insulating layer 132 is too small, it will exacerbate powder shedding from the second insulating layer 132, failing to ensure proper coverage of the positive electrode 100, which will lead to side reactions and other problems. Excessive porosity provides potential space for lithium ions after delithiation. If the discharge rate is too high, lithium ions will adhere to the pore space inside the insulating layer 130 before being inserted and removed. These lithium ions will no longer participate in the cycle, thus affecting the cycle performance of the battery 10.

[0139] In some embodiments, the D50 of the insulating layer 130 satisfies: D50 = 40 μm ~ 90 μm, and the D99 of the insulating layer 130 satisfies: D99 = 60 μm ~ 120 μm.

[0140] The aforementioned particle size distribution of the insulating layer 130 ensures uniform coating of the insulating layer 130 and effectively improves the performance balance of the positive electrode 100. Understandably, excessively small particle size leads to particle agglomeration, which is detrimental to the uniform coating of the insulating layer 130. Excessively large particle size results in abnormal grain size consistency within the particles, leading to poor porosity distribution in the insulating layer 130. Macroscopically, this manifests as difficulty in uniformly coating the insulating layer 130, potentially causing abnormalities such as foil leakage.

[0141] The above embodiments provide a detailed description of the first type of embodiment. In this first type of embodiment, the negative electrode 300 adopts a single-piece structure 301, and the positive electrode 100 has an insulating layer 130 formed at each bend 102, with the insulating layer 130 formed on the first surface 111 and the second surface 112 of the positive electrode current collector 110. In the second type of embodiment, by adding a dual-piece structure 302 to the negative electrode 300, the energy density of the battery 10 can be further improved.

[0142] Figure 13 A plan view of a negative electrode sheet provided according to a second type embodiment of this application is shown; Figure 14 A first surface 111 of a positive electrode sheet according to a second type embodiment of this application is shown; Figure 15 A second surface 112 of a positive electrode sheet provided according to a second type embodiment of this application is shown.

[0143] In the second type of embodiment of this application, the positive electrode 100 has a structure and layout that is substantially the same as that of the first type of embodiment described above. The difference is that in this second type of embodiment, the bend 102 on the positive electrode 100 corresponding to the negative electrode 300 of the double-plate structure 302 can be changed. Since the negative electrode 300 of the double-plate structure 302 can wrap the bend 102 on the outside, the outer side of the bend 102 can be replaced by the positive electrode active material layer 120 instead of the insulating layer 130, thereby improving the energy density of the battery 10 and ensuring that the negative electrode 300 covers the positive electrode 100.

[0144] Please refer to Figure 4 The positive electrode 100 has 10 layers. The top layer 101 is the first layer 1011, and the bottom layer 101 is the second layer 1012. Two negative electrode sheets 300 are arranged to the right of the positive electrode 100, forming a double-sheet structure 302. Two negative electrode sheets 300 are also arranged to the left of the positive electrode 100, also forming a double-sheet structure 302. Simultaneously, a single-sheet negative electrode sheet 300 with a single-sheet structure 301 is also arranged to the left of the positive electrode 100, located at the bottom. Figure 4 As can be seen from the diagram, the negative electrode 300 of the dual-plate structure 302 can cover the outside of the bend 102 of the positive electrode 100, so that the first insulating layer 131 does not need to be provided on the outside of the positive electrode 100 on the right side, and the second insulating layer 132 does not need to be provided on the outside of the positive electrode 100 on the left side. The empty space can be replaced by the positive electrode active material layer 120, thereby improving the energy density of the battery 10. In addition, due to the shape of the dual-plate structure 302, a soft tab 400 can be provided for the two negative electrode 300, which can also increase the space occupied by the tab and improve the energy density of the battery 10.

[0145] Figure 14 and Figure 15 The layout of the first surface 111 and the second surface 112 can be combined with the first embodiment described above. Figure 5 and Figure 6 The main difference between the two lies in the different bends 102. In the first type of embodiment, there is a first insulating layer 131 and a second insulating layer 132 at each bend 102. In the second type of embodiment, a portion of the first insulating layer 131 or the second insulating layer 132 may be missing according to the arrangement of the bends 102.

[0146] Other aspects of this second type of embodiment can be referred to the aforementioned first type of embodiment, and will not be repeated here. Other aspects mainly include the design of the width, length, and thickness of the insulating layer 130.

[0147] 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", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0148] In the description of this application, it should be understood that the terms "comprising" and "having" and any variations thereof used in the embodiments of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such process, method, product, or device.

[0149] Unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the connection within two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances. Furthermore, the terms "first," "second," etc., 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.

[0150] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A battery cell, characterized in that, include: Positive electrode, negative electrode, separator, The positive electrode includes: Positive current collector; Multiple coating areas are formed on the surface of the positive electrode current collector, and the coating areas include a positive electrode active material layer; And multiple uncoated areas are formed on the surface of the positive electrode current collector, the uncoated areas including an insulating layer. In this configuration, multiple coated areas and multiple uncoated areas are sequentially connected and alternately arranged, and the insulating layer is connected between two adjacent positive electrode active material layers. The positive current collector includes a first surface and a second surface opposite to each other. The coated area includes a first coated area formed on the first surface and a second coated area formed on the second surface. The uncoated area includes a first uncoated area formed on the first surface and a second uncoated area formed on the second surface. The insulating layer includes a first insulating layer formed on the first uncoated area and a second insulating layer formed on the second uncoated area. The positive electrode sheet is bent to form a multi-layered stacked structure, with bends between adjacent layers. These bends correspond to the uncoated areas of the current collector. The diaphragm is continuously bent and bonded to both sides of the positive electrode sheet; The negative electrode includes a monolithic structure sandwiched between two adjacent layers and located on the side of the separator away from the positive electrode.

2. The battery cell according to claim 1, characterized in that, The thickness of the insulating layer is h1, and h1 satisfies: 4μm≤h1≤60μm.

3. The battery cell according to claim 1, characterized in that, The average thickness of the insulating layer is h2, and the average thickness of the positive electrode current collector is h3. h2 and h3 satisfy the following relationship: 0.26h3≤h2≤4h3, 4μm≤h2≤60μm, 5μm≤h3≤20μm.

4. The battery cell according to claim 2 or 3, characterized in that, The average thickness of the positive electrode active material layer is h4, and h2 and h4 satisfy the following relationship: 0.33h4≤h2≤1.5h4, 35μm≤h4≤80μm.

5. The battery cell according to claim 1, characterized in that, The uncoated area includes two sub-regions extending in the width direction of the positive electrode sheet, and the boundary line between the two sub-regions extends in the width direction of the positive electrode sheet. The sub-partition has a dimension L1 along the length of the electrode, and L1 satisfies: 0.1mm≤L1≤1.5mm.

6. The battery cell according to claim 5, characterized in that, Along the length of the positive electrode sheet, the thickness of the first insulating layer alternates between gradually increasing from one end near the positive active material layer to the boundary line and gradually decreasing from one end near the positive active material layer to the boundary line; the thickness of the second insulating layer alternates between gradually decreasing from one end near the positive active material layer to the boundary line and gradually increasing from one end near the positive active material layer to the boundary line; the projections of the first insulating layer and the second insulating layer overlap along the thickness direction of the positive electrode sheet; when the thickness of the first insulating layer gradually increases from one end near the positive active material layer to the boundary line, the thickness of the second insulating layer at the corresponding position along the thickness direction of the positive electrode sheet gradually decreases from one end near the positive active material layer to the boundary line.

7. The battery cell according to claim 1, characterized in that, Along the length of the positive electrode sheet, the ratio of the width of the first insulating layer to the width of the second insulating layer is P, where P satisfies: 0.33 ≤ P ≤ 3.

8. The battery cell according to claim 1, characterized in that, A single-sided coating area is formed at the end of the positive electrode sheet along its length direction. The single-sided coating area includes the positive electrode active material layer and is formed on one or both sides of the positive electrode sheet.

9. The battery cell according to claim 8, characterized in that, A first edge insulating layer is provided between the positive electrode active material layer on the single-sided coating area and the edge of the positive electrode current collector along its length direction. The width of the first edge insulating layer is S1. A second edge insulating layer is provided on the positive electrode current collector. The second edge insulating layer is located on the surface opposite to the single-sided coating area and adjacent to the positive electrode active material layer. The width of the second edge insulating layer is S2. S1 and S2 satisfy: 0.1mm≤S1≤0.5mm, 0.1mm≤S2≤0.5mm.

10. The battery cell according to claim 1, characterized in that, The negative electrode also includes a dual-plate structure, which is formed by connecting two consecutive single-plate structures through a connecting part. The connecting part forms a negative electrode bend, which is correspondingly arranged with the bend and located on the outside of the bend.

11. The battery cell according to claim 10, characterized in that, The insulating layer on the uncoated area of ​​the surface of the positive current collector corresponding to the negative electrode bend is replaced by an active material layer.

12. A battery, characterized in that, The battery cell included in any one of claims 1-11.

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