Battery and electric device

Abstract

The present application discloses a battery and an electric device. The battery comprises: a case having a storage cavity, wherein cavity walls of the storage cavity include a first wall, and the first wall is provided with a thinned region; and a battery cell arranged in the thinned region of the storage cavity, the first wall being located on at least one side of the battery cell in the thickness direction. The battery cell comprises positive electrode sheets and negative electrode sheets; in the thickness direction of the battery cell, the positive electrode sheet located on the outermost side of the battery cell has an abutting portion in contact with the thinned region, the abutting portion comprises a current collector, the current collector has a first surface facing the thinned region and a second surface facing away from the thinned region, and the second surface is provided with an insulating layer; and in the thickness direction of the battery cell, the projections of two side edges of each negative electrode sheet in the width direction fall within the surface of the insulating layer. The battery of the present application can effectively improve the safety of batteries.

Description

Batteries and electrical equipment

[0001] Related applications

[0002] This application claims priority to Chinese patent application No. 202520568252.8, filed on March 28, 2025, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of battery technology, and in particular to a battery and an electrical device. Background Technology

[0004] In related technologies, batteries consist of an aluminum-plastic film and battery cells. After the aluminum-plastic film is perforated, it has a storage cavity in which the battery cells can be placed. It is conceivable that the larger the storage cavity, the larger the volume of battery cells that can be placed in the aluminum-plastic film, which can achieve a higher energy density for the battery.

[0005] Typically, battery dimensions are fixed. Therefore, to increase battery energy density, the PP layer on the storage cavity is often thinned or removed. However, this can cause the negative electrode of the cell to come into contact with the aluminum layer, leading to a short circuit and reducing battery safety.

[0006] Application content

[0007] This application aims to address at least one of the technical problems existing in the prior art. To this end, this application proposes a battery that can effectively improve battery safety.

[0008] This application also proposes an electrical device.

[0009] The battery according to a first aspect embodiment of this application includes:

[0010] The housing has a storage cavity, the cavity wall of which includes a first wall having a thinned area;

[0011] A battery cell is disposed in the thinned area of ​​the storage cavity, and the first wall is located on at least one side in the thickness direction of the battery cell; the battery cell includes a positive electrode and a negative electrode, and along the thickness direction of the battery cell, the outermost positive electrode has an abutment portion that contacts the thinned area, the abutment portion includes a current collector, the current collector has a first surface facing the thinned area and a second surface facing away from the thinned area, the second surface being provided with an insulating layer;

[0012] Along the thickness direction of the battery cell, the projections of the two sides of the negative electrode sheet in the width direction are within the surface of the insulating layer. The battery according to the embodiments of this application has at least the following beneficial effects: the battery cell is disposed in a storage cavity, wherein the first wall of the storage cavity has a thinned area, and the thinned area can improve the energy density of the battery. Simultaneously, the second surface of the contact portion is provided with an insulating layer, and the projections of the two sides of the negative electrode sheet in the width direction are within the surface of the insulating layer. Thus, it is possible to effectively prevent the negative electrode sheet from contacting the thinned area, thereby improving the safety of the battery.

[0013] According to some embodiments of the battery in this application, the second surface is further provided with a positive electrode active material layer, and the insulating layer is disposed on both sides of the positive electrode active material layer along the width direction of the positive electrode sheet.

[0014] According to some embodiments of the battery in this application, along the width direction of the positive electrode sheet, the size of the insulating layer located on either side of the positive electrode active material layer is A, the size of the negative electrode active material layer of the negative electrode sheet is B, and the size of the positive electrode active material layer is C. The relationship between A, B and C satisfies: A≥0.5(BC)+0.1 mm.

[0015] The battery according to some embodiments of this application further includes at least one of the following features (1) to (5): (1) BC ≥ 0.2 mm; (2) the insulating layer located on either side of the positive active material layer along the width direction of the positive electrode sheet extends beyond the negative electrode sheet by a dimension D, where the value of D is greater than or equal to 0.1 mm and less than or equal to 1.5 mm; (3) the insulating layer located on either side of the positive active material layer along the width direction of the positive electrode sheet extends beyond the negative electrode sheet by a dimension D, where the value of D is greater than or equal to 0.3 mm and less than or equal to 1.3 mm; (4) the insulating layer located on either side of the positive active material layer along the width direction of the positive electrode sheet extends beyond the negative electrode sheet by a dimension D, where the value of D is greater than or equal to 0.3 mm and less than or equal to 0.7 mm; (5) the thickness of the positive active material layer is T1, the thickness of the insulating layer is T2, and the relationship between T1 and T2 satisfies: 0.2T1≤T2≤T1.

[0016] According to some embodiments of the present application, the storage cavity of the battery further includes a second wall surrounding an edge connected to the first wall. The thinned area of ​​the first wall includes a first heat-sealing layer, a first metal layer, and a first outer layer stacked together. The second wall includes a second heat-sealing layer, a second metal layer, and a second outer layer stacked together. The thickness of the first heat-sealing layer is less than the thickness of the second heat-sealing layer. The first surface is in contact with the first heat-sealing layer.

[0017] According to some embodiments of the battery in this application, the thickness of the first heat-sealing layer is H, and the thickness of the second heat-sealing layer is G, wherein the relationship between H and G satisfies: H < 0.5G.

[0018] According to some embodiments of the battery in this application, the contact portion further includes a positive electrode active material layer, and two insulating layers are respectively located on both sides of the positive electrode active material layer. The thickness of the positive electrode active material layer is T1, and the thickness of the insulating layer is T2. The relationship between T1 and T2 satisfies: 0.2T1≤T2≤T1.

[0019] According to some embodiments of the present application, the storage cavity of the battery further includes a second wall surrounding an edge connected to the first wall. The thinned area of ​​the first wall includes a first metal layer and a first outer layer stacked together. The second wall includes a second heat-sealing layer, a second metal layer, and a second outer layer stacked together. The first surface contacts the first metal layer.

[0020] According to some embodiments of the battery in this application, the first surface is also provided with the insulating layer along the width direction of the positive electrode sheet.

[0021] According to some embodiments of the present application, the positive electrode and the negative electrode are stacked and wound to form the battery cell. The positive electrode includes a first segment and a second segment connected to each other. The end of the first segment away from the second segment is the winding end point of the positive electrode, and the end of the second segment away from the first segment is the winding start point of the positive electrode. At least a portion of the first segment forms the abutment portion.

[0022] According to some embodiments of the battery in this application, the insulating layer is also provided on both sides of the second segment along the width direction of the positive electrode sheet.

[0023] According to some embodiments of the present application, the battery has multiple positive and negative electrode sheets. The multiple positive and negative electrode sheets are stacked alternately to form the battery cell. The positive electrode sheet includes a first electrode sheet and a second electrode sheet. The two first electrode sheets are located on the outermost side of the battery cell in the thickness direction. The second electrode sheet is located between two adjacent negative electrode sheets. The first electrode sheet forms the abutment portion.

[0024] According to some embodiments of the battery in this application, the insulating layer is also provided on both sides of the second electrode along the width direction of the positive electrode.

[0025] The electrical device according to the second aspect of this application includes a battery as described in any one of the first aspect embodiments, the battery being installed in the main body of the electrical device for supplying power to the main body of the electrical device.

[0026] The electrical device according to the embodiments of this application has at least the following beneficial effects: the battery cell is disposed in a storage cavity, wherein the first wall of the storage cavity has a thinned area, and the thinned area can improve the energy density of the battery. Simultaneously, the second surface of the contact portion is provided with an insulating layer, and the projections of the two sides of the negative electrode sheet in the width direction are within the surface of the insulating layer. This effectively prevents the negative electrode sheet from contacting the thinned area, thereby improving battery safety. Furthermore, the electrical device having this battery also has higher safety.

[0027] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0028] The present application will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0029] Figure 1 is a schematic diagram of the battery cell in the first embodiment of this application;

[0030] Figure 2 is a schematic diagram of the positive electrode plate in the battery cell of some embodiments of this application;

[0031] Figure 3 is a cross-sectional view of the battery in the thickness direction according to the first embodiment of this application;

[0032] Figure 4 is a cross-sectional view of the battery in the thickness direction according to the second embodiment of this application;

[0033] Figure 5 is a schematic diagram of the battery cell in the second embodiment of this application;

[0034] Figure 6 is a schematic diagram of the battery cell in the third embodiment of this application;

[0035] Figure 7 is a schematic diagram of the battery cell in the fourth embodiment of this application;

[0036] Figure 8 is a schematic diagram of the battery cell in the fifth embodiment of this application;

[0037] Figure 9 is a schematic diagram of an electrical device according to an embodiment of this application.

[0038] Reference numerals: Casing 100; Storage cavity 200; First wall 210; First heat-sealing layer 211; First metal layer 212; First outer layer 213; Thinned area 220; Groove 230; Second wall 240; Second heat-sealing layer 241; Second metal layer 242; Second outer layer 243; Cell 300; Abutting part 310; Positive electrode 400; Positive current collector 410; Positive active material layer 420; Insulating layer 430; First section 440; Second section 450; First electrode 460; Second electrode 470; Negative electrode 500; Negative current collector 510; Negative active material layer 520; Battery 10; Electrical device 20. Detailed Implementation

[0039] The embodiments of this application are described in detail below. Examples of these embodiments are shown 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.

[0040] In the description of this application, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0041] In the description of this application, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0042] In the description of this application, unless otherwise expressly defined, terms such as "setup," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this application in conjunction with the specific content of the technical solution.

[0043] In the description of this application, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are 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.

[0044] The battery can be a lithium-ion battery, sodium-ion battery, sodium-lithium-ion battery, lithium metal battery, sodium metal battery, lithium-sulfur battery, magnesium-ion battery, nickel-metal hydride battery, nickel-cadmium battery, lead-acid battery, etc., and the embodiments of this application are not limited to this.

[0045] A battery typically consists of a cell. The cell includes a positive electrode, a negative electrode, and a separator. During charging and discharging, active ions (such as lithium ions) move back and forth between the positive and negative electrodes, inserting and releasing. The separator, positioned between the positive and negative electrodes, prevents short circuits while allowing active ions to pass through.

[0046] This application provides an electrical device that uses a battery as a power source. The electrical device can be, but is not limited to, a mobile phone, tablet, laptop, power tool, electric vehicle, electric car, ship, etc.

[0047] In related technologies, batteries consist of an aluminum-plastic film and battery cells. After the aluminum-plastic film is perforated, it has a storage cavity in which the battery cells can be placed. It is conceivable that the larger the storage cavity, the larger the volume of battery cells that can be placed in the aluminum-plastic film, which can achieve a higher energy density for the battery.

[0048] Typically, battery dimensions are fixed. Therefore, to improve battery energy density, the PP layer on the storage cavity is usually thinned or removed. However, this can cause the negative electrode of the cell to come into contact with the aluminum layer (the negative electrode usually protrudes a certain length from the positive electrode to effectively prevent lithium plating), leading to a short circuit and reducing battery safety. Therefore, this application proposes a battery.

[0049] Referring to Figures 1 to 8, in some embodiments, the battery includes a casing 100 and a cell 300. The casing 100 has a storage cavity 200, which can be a cube, cuboid, or cylinder. The shape of the storage cavity 200 is not specifically limited. The cavity wall of the storage cavity 200 includes a first wall 210, which is located on at least one side in the thickness direction of the cell 300. The first wall 210 is provided with a thinning region 220. Specifically, the thinning region 220 refers to thinning the thickness of the first wall 210. For example, after thinning the first wall 210, its thickness is less than half of its original thickness. This can increase the effective volume of the storage cavity 200, thereby increasing the energy density of the battery.

[0050] The battery cell 300 is disposed in the thinning region 220 of the storage cavity 200. The battery cell 300 includes a positive electrode 400 and a negative electrode 500 stacked together. Specifically, the stacked positive electrode 400 and negative electrode 500 can be wound to form the battery cell 300, or the positive electrode 400 and negative electrode 500 can be alternately stacked to form a laminated battery cell 300. The methods of winding or laminating to form the battery cell 300 are existing technologies and will not be described in detail here.

[0051] The battery cell 300 has an abutment portion 310 where the outermost positive electrode sheet 400 in the thickness direction contacts the thinned region 220. There may be two abutment portions 310, each disposed in the thickness direction of the battery cell 300. Each abutment portion 310 includes a current collector, which may be a positive electrode current collector 410. The current collector has a first surface facing the thinned region 220 and a second surface facing away from the thinned region 220. The second surface is provided with an insulating layer 430. In other words, the abutment portion 310 has a first surface facing the thinned region 220 and a second surface facing away from the thinned region 220.

[0052] The contact portion 310 specifically refers to the portion formed when, after the positive electrode 400 and negative electrode 500 are stacked and wound to form the battery cell 300, the winding tail end of the positive electrode 400 wraps around the negative electrode 500, thus forming the contact portion 310 in the thickness direction of the battery cell 300. Alternatively, after multiple positive electrode 400s and multiple negative electrode 500s are alternately stacked, two positive electrode 400s are located on opposite sides of the battery cell 300 in the thickness direction, thus forming the contact portion 310. Please refer to Figures 3 and 4, which show cross-sectional views of the battery cell 300 in the thickness direction. When the battery cell 300 is a wound structure, it can be cut from the middle position of the battery cell 300; when the battery cell 300 is a stacked structure, it can also be cut from the middle position of the battery cell 300. Specifically, please refer to Figures 5 to 8, which illustrate cross-sectional views of a wound-type battery cell 300 and a stacked-type battery cell 300. A positive electrode 400 and a negative electrode 500 are stacked and wound to form the battery cell 300. The positive electrode 400 includes a first segment 440 and a second segment 450 connected to each other. The end of the first segment 440 away from the second segment 450 is the winding end point of the positive electrode 400, and the end of the second segment 450 away from the first segment 440 is the winding start point of the positive electrode 400. At least a portion of the first segment 440 forms an abutment portion 310. An insulating layer 430 can be provided on both the first segment 440 and the second segment 450. For example, the second segment 450 is provided with an insulating layer 430. Two insulating layers 430 are located on either side of the width of the second segment 450. This facilitates the processing of the positive electrode 400, simplifies the processing technology, and improves efficiency. Furthermore, this can increase the battery energy density and prevent short circuits between the negative electrode 500 and the thinned area 220, as well as between the positive electrode 400 and the negative electrode 500. It should be noted that when the second segment 450 has an insulating layer 430, the width of the second segment 450 is greater than the width of the negative electrode 500; when the second segment 450 does not have an insulating layer 430, the width of the second segment 450 is less than the width of the negative electrode 500. Alternatively, multiple positive electrode 400s and multiple negative electrode 500s can be provided, and multiple positive electrode 400s and multiple negative electrode 500s can be alternately stacked to form a battery cell 300. The positive electrode 400 includes a first electrode 460 and a second electrode 470. The two first electrodes 460 are located on the outermost sides of the cell 300 in the thickness direction, and the second electrode 470 is located between two adjacent negative electrodes 500. The first electrodes 460 form an abutment portion 310. An insulating layer 430 can be provided on both the first electrode 460 and the second electrode 470, or an insulating layer 430 can be provided only on the first electrode 460. For example, the second electrode 470 is provided with an insulating layer 430, with two insulating layers 430 located on opposite sides of the second electrode 470 in the width direction. This can improve the battery energy density and prevent short circuits between the negative electrode 500 and the thinned region 220, as well as between the positive electrode 400 and the negative electrode 500.It should be noted that when the second electrode 470 is provided with an insulating layer 430, the width of the second electrode 470 is greater than the width of the negative electrode 500. When the second electrode 470 is not provided with an insulating layer 430, the width of the second electrode 470 is less than the width of the negative electrode 500.

[0053] Please refer to Figure 1. The positive electrode 400 and negative electrode 500 are described below. The positive electrode 400 includes a positive current collector 410, a positive active material layer 420, and an insulating layer 430. The positive active material layer 420 and the insulating layer 430 are disposed on both sides of the positive current collector 410 in the thickness direction. It should be noted that the positive active material layer 420 can be disposed on both sides of the positive current collector 410 in the thickness direction, or it can be disposed on only one side of the positive current collector 410 in the thickness direction; no specific limitation is made here. For example, the two outermost positive electrode sheets 400 located in the thickness direction of the cell 300 may only have one positive active material layer 420. That is, the positive electrode sheet 400 can be either a single-sided sheet or a double-sided sheet, as shown in Figures 1 and 5. Along the width direction of the positive current collector 410, the two insulating layers 430 are respectively located on both sides of the positive active material layer 420. That is, the positive electrode active material layer 420 is located between the two insulating layers 430. Alternatively, in some cases, only the insulating layer 430 is provided on one side of the positive electrode current collector 410 in the thickness direction, and the positive electrode active material layer 420 is not provided. Alternatively, the side of the contact portion 310 facing away from the negative electrode sheet 500 has an insulating layer 430, and the two insulating layers 430 are respectively located on both sides of the width direction of the contact portion 310. Or, the positive electrode sheet 400 located in the middle of the cell 300 does not have an insulating layer 430. For details, please refer to Figures 5 to 8. The negative electrode sheet 500 includes a negative electrode current collector 510 and a negative electrode active material layer 250, and the negative electrode active material layer 250 is provided on both sides of the negative electrode current collector 510 in the thickness direction. It should be noted that Figures 5 to 8 all show cross-sectional views when the cell 300 is a wound structure or a stacked structure.

[0054] In this configuration, along the thickness direction of the cell 300, the projections of both sides of the negative electrode 500 in the width direction lie within the surface of the insulating layer 430. Consequently, along the thickness direction of the positive electrode 400, the projection of the positive active material layer 420 falls within the projection range of the negative active material layer 250, and the projection of the insulating layer 430 partially overlaps with the projection of the negative active material layer 250. Specifically, along the width direction of the positive electrode 400, the size of the positive active material layer 420 is smaller than the size of the negative active material layer 250, meaning the amount of negative active material is greater than the amount of positive active material, which effectively prevents lithium plating in the battery. Along the width direction of the positive electrode 400, the size of the positive electrode 400 is larger than the size of the negative electrode 500, and the projection of the portion of the negative active material layer 250 extending beyond the positive active material layer 420 falls on the insulating layer 430.

[0055] Specifically, the battery cell 300 is disposed in the storage cavity 200, wherein the first wall 210 of the storage cavity 200 has a thinning area 220. The thinning area 220 can improve the energy density of the battery. At the same time, the second surface of the contact portion 310 is provided with an insulating layer 430, and the projections of the two sides of the negative electrode 500 in the width direction are within the surface of the insulating layer 430. In this way, the negative electrode 500 can be effectively prevented from contacting the thinning area 220, thereby improving the safety of the battery.

[0056] To elaborate further, the width direction of the positive electrode 400 is the same as the length direction of the cell 300. The insulating layer 430 can effectively prevent the negative electrode 500 at both ends of the cell 300 from contacting the casing 100, thereby improving the safety of the battery.

[0057] Further, referring to Figure 1, in some embodiments, the width direction of the abutment portion 310 is the same as the width direction of the positive electrode 400. The dimension of the insulating layer 430 is A, where A ≥ 0.2 mm. Specifically, A can be 0.2 mm, 0.3 mm, 0.4 mm, or 0.5 mm. If the dimension of the insulating layer 430 is less than 0.2 mm, then due to the small size of the insulating layer 430, the negative electrode active material layer 250 may extend beyond the insulating layer 430 in the width direction of the positive electrode 400 and then contact the housing 100, causing a short circuit problem.

[0058] Further, referring to Figure 1, in some embodiments, along the width direction of the positive electrode 400, the size of the insulating layer 430 located on either side of the positive electrode active material layer 420 is A, the size of the negative electrode active material layer 250 is B, and the size of the positive electrode active material layer 420 is C. The relationship between A, B, and C satisfies: A ≥ 0.5(BC) + 0.1 mm. Specifically, the width direction of the positive electrode 400 can also be the width direction of the negative electrode 500. The negative electrode active material layer 250 extends beyond the positive electrode active material layer 420 in the width direction of the positive electrode 400, and the extension can be BC. When A is less than 0.5(BC) + 0.1 mm, the size of the insulating layer 430 is too small, which may cause the negative electrode active material layer 250 to extend beyond the insulating layer 430 in the width direction of the positive electrode 400 and then contact the housing 100, causing a short circuit.

[0059] Further, referring to Figure 1, in some embodiments, along the width direction of the positive electrode sheet 400, the size of the negative electrode active material layer 250 is B, and the size of the positive electrode active material layer 420 is C, with the difference between B and C (BC) ≥ 0.2 mm. Specifically, the value of BC can be greater than 0.2 mm, 0.3 mm, 0.4 mm, or 0.5 mm. When the value of BC is less than 0.2 mm, the difference between the amount of negative electrode active material and the amount of positive electrode active material is small, which may lead to lithium plating problems in the battery.

[0060] Further, in some embodiments, the width of the positive electrode 400 is E, and the width of the negative electrode 500 is F, where the difference between E and F (EF) is ≥ 0.2 mm. The insulating layer 430 located on either side of the positive electrode active material layer 420 extends beyond the negative electrode 500 by a dimension D, where D = 0.5 (EF). Specifically, EF can be equal to 0.2 mm, 0.3 mm, 0.4 mm, 0.6 mm, 1 mm, 1.4 mm, 2 mm, 2.6 mm, or 3 mm. D = 0.1 mm to 1.5 mm, or D = 0.3 mm to 1.3 mm, or D = 0.3 mm to 0.7 mm. Specifically, D can be equal to 0.1 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.7 mm, 1 mm, 1.2 mm, 1.3 mm, 1.5 mm, or 1.6 mm. If the value of EF is less than 0.2 mm, that is, D is less than 0.1 mm, then on the one hand, the positive electrode 400 will not be able to completely block the negative electrode 500, and the negative electrode 500 may come into contact with the casing 100. On the other hand, because the value of EF is too small, the installation accuracy required when installing the positive electrode 400 and the negative electrode 500 will be high, which will reduce the installation efficiency of the battery. If D is greater than 1.5 mm, then there will be too much insulation layer 430, resulting in unnecessary waste.

[0061] Furthermore, in some embodiments, the thickness of the positive electrode active material layer 420 is T1, and the thickness of the insulating layer 430 is T2, with the relationship between T1 and T2 satisfying: 0.2T1 ≤ T2 ≤ T1. Specifically, T2 can be equal to 0.2T1, 0.4T1, 0.5T1, 0.7T1, or T1. If T2 is less than 0.2T1, the thickness of the insulating layer 430 is relatively small, which may result in poor insulation between the insulating layer 430 and the negative electrode 500 and the casing 100. If T2 is greater than T1, the thickness of T2 is relatively large, which may indirectly increase the thickness of the positive electrode 400 and reduce the energy density of the battery.

[0062] Further, referring to Figure 3, which is a schematic diagram of the wound cell 300 in the electrode width direction, in some embodiments, the storage cavity 200 further includes a second wall 240 surrounding the circumferential edge connected to the first wall 210. The thinned region 220 of the first wall 210 includes a first heat-sealing layer 211, a first metal layer 212, and a first outer layer 213 stacked together. The first heat-sealing layer 211 may be a PP layer, the first metal layer 212 may be an aluminum layer, and the first outer layer 213 may be a nylon layer. The second wall 240 includes a second heat-sealing layer 241, a second metal layer 242, and a second outer layer 243 stacked together. The second heat-sealing layer 241 may be a PP layer, the second metal layer 242 may be an aluminum layer, and the second outer layer 243 may be a nylon layer. Specifically, the first heat-sealing layer 211 may have a groove 230, the wall thickness of which is less than the thickness of the second heat-sealing layer 241. The battery cell 300 is located in the groove 230, and its first surface contacts the first heat-sealing layer 211 (the bottom wall of the groove 230). This allows the storage cavity 200 to hold more battery cells 300, thereby increasing the energy density of the battery.

[0063] Furthermore, in some embodiments, the thickness of the first heat-sealing layer 211 is H, and the thickness of the second heat-sealing layer 241 is G, with the relationship between H and G satisfying: H < 0.5G. Specifically, the depth of the groove 230 depends on how much of the first heat-sealing layer 211 is removed. It is conceivable that the smaller the depth of the groove 230, the more of the first heat-sealing layer 211 is removed, and the larger the space of the storage cavity 200 is. Therefore, H < 0.5G can significantly improve the energy density of the battery.

[0064] Further, referring to FIG4, in some embodiments, the storage cavity 200 further includes a second wall 240 surrounding the circumferential edge connected to the first wall 210. The thinned area 220 of the first wall 210 includes a first metal layer 212 and a first outer layer 213 stacked together. The first metal layer 212 may be an aluminum layer, and the first outer layer 213 may be a nylon layer. That is, the first heat-sealing layer 211 on the first wall 210 is completely removed. The second wall 240 includes a second heat-sealing layer 241, a second metal layer 242, and a second outer layer 243 stacked together. The second heat-sealing layer 241 may be a PP layer, the second metal layer 242 may be an aluminum layer, and the second outer layer 243 may be a nylon layer. The first surface of the abutment portion 310 contacts the first metal layer 212. In this embodiment, after the first heat-sealing layer 211 on the first wall 210 is completely removed, the space of the storage cavity 200 can be greatly increased, thereby increasing the energy density of the battery. When the positive electrode 400 comes into contact with the first metal layer 212, the insulating layer 430 and the positive active material layer 420 together achieve the isolation between the first metal layer 212 and the negative active material layer 250, which can improve the safety of the battery.

[0065] Referring to Figure 9, in some embodiments, the electrical device 20 includes a battery 10 as described in any of the above embodiments. The battery 10 is installed in the main body of the electrical device 20 to supply power to the main body of the electrical device 20. Specifically, in the battery 10, the cell 300 is disposed in the storage cavity 200. The first wall 210 of the storage cavity 200 has a thinned area 220. The thinned area 220 can improve the energy density of the battery. At the same time, the second surface of the contact portion 310 is provided with an insulating layer 430, and the projections of the two sides of the negative electrode 500 in the width direction are within the surface of the insulating layer 430. Thus, the negative electrode 500 can be effectively prevented from contacting the thinned area 220, thereby improving the safety of the battery. Furthermore, the electrical device 20 with this battery 10 also has higher safety.

[0066] Performance testing methods:

[0067] 1) Capacity: 0.5C constant current and constant voltage charging to the upper limit voltage, 0.02C cutoff; 0.2C constant current discharging to the cutoff voltage.

[0068] 2) Fall:

[0069] Full charge of the battery cell: Charge at 0.5C constant current and constant voltage to the upper limit voltage, cut off at 0.02C. 1. Fix the battery cell in the designated clamp and drop it from a height of 1m onto a marble floor; 2. Perform directional drops according to the following requirements: drop once from each of the 6 sides and 4 corners, for a total of 10 drops. This constitutes one cycle. 10 cycles need to be performed, for a total of 100 drops.

[0070] 3) Hot box

[0071] Full charge of the battery cell: Charge at a constant current and constant voltage of 0.5C to the upper limit voltage, and cut off at 0.02C. Place the battery cell in an oven and heat it using convection or circulating hot air at an initial temperature of 25±3℃. Increase the oven temperature at a rate of 5±2℃ / min to 130±2℃ and maintain it for 60 minutes. Meets the standard: No fire or explosion.

[0072] Experimental Example

[0073] Aluminum-plastic film with an outer layer PA + middle layer Al + inner layer PP structure was used to prepare aluminum-plastic film samples with and without thinning treatment, as well as with and without an insulating layer. Among them, Example 1 is a conventional wound cell with the following external dimensions: Max thickness 4.82 mm × Max width 63.38 mm × Max length 88 mm and cell capacity 5668 mAh.

[0074] The only difference between Examples 2-11 and Example 1 is whether there is a thinning area 220, the degree of thinning of the first heat-sealing layer 211, and whether the insulating layer 430 on the positive electrode 400 exceeds the size of the negative electrode 500 in the width direction. The rest is the same as Example 1, as shown in Table 1.

[0075] Table 1

[0076] In Table 1, Examples 1 and 2-11 are compared. Example 1 is a conventional battery cell 300, which does not have a thinning area 220, and the contact portion 310 does not have an insulating layer 430. That is, the difference between Examples 1 and 2-11 is the presence or absence of a thinning area 220. Examples 2 and 3-11 are also compared. Example 2 is also a conventional battery cell 300, which has a thinning area 220, but the contact portion 310 does not have an insulating layer 430. Examples 3 to 11 are the battery cell 300 of this application, which has a thinning area 220 and an insulating layer 430, the difference being the value of D. Examples 1-10 show that the thinning area 220 can effectively improve the battery's energy density. Examples 2-11 show that after setting an insulating layer 430 of a reasonable size on the contact portion 310, the battery's drop pass rate and hot box pass rate can also be improved, thereby improving battery safety.

[0077] The embodiments of this application have been described in detail above with reference to the accompanying drawings. However, this application is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of this application. Furthermore, unless otherwise specified, the embodiments and features described in the embodiments of this application can be combined with each other.

Claims

1. Battery, including: The housing has a storage cavity, the cavity wall of which includes a first wall having a thinned area; A battery cell is disposed in the thinned area of ​​the storage cavity, and the first wall is located on at least one side in the thickness direction of the battery cell; the battery cell includes a positive electrode and a negative electrode, and along the thickness direction of the battery cell, the outermost positive electrode has an abutment portion that contacts the thinned area, the abutment portion includes a current collector, the current collector has a first surface facing the thinned area and a second surface facing away from the thinned area, the second surface being provided with an insulating layer; Along the thickness direction of the battery cell, the projections of the two sides of the negative electrode sheet in the width direction are within the surface of the insulating layer.

2. The battery of claim 1, wherein, The second surface is further provided with a positive electrode active material layer, and the insulating layer is provided on both sides of the positive electrode active material layer along the width direction of the positive electrode sheet.

3. The battery according to claim 2, wherein, Along the width direction of the positive electrode sheet, the size of the insulating layer located on either side of the positive electrode active material layer is A, the size of the negative electrode active material layer of the negative electrode sheet is B, and the size of the positive electrode active material layer is C. The relationship between A, B, and C satisfies: A ≥ 0.5(BC) + 0.1 mm.

4. The battery according to claim 3, wherein, It also includes at least one of the following features (1) to (5): (1) The BC is ≥ 0.2 mm; (2) The insulating layer located on either side of the positive electrode active material layer along the width direction of the positive electrode sheet extends beyond the negative electrode sheet by a dimension D, where the value of D is greater than or equal to 0.1 mm and less than or equal to 1.5 mm. (3) The insulating layer located on either side of the positive electrode active material layer along the width direction of the positive electrode sheet extends beyond the negative electrode sheet by a dimension D, where the value of D is greater than or equal to 0.3 mm and less than or equal to 1.3 mm. (4) The insulating layer located on either side of the positive electrode active material layer along the width direction of the positive electrode sheet extends beyond the negative electrode sheet by a dimension D, where the value of D is greater than or equal to 0.3 mm and less than or equal to 0.7 mm. (5) The thickness of the positive electrode active material layer is T1, the thickness of the insulating layer is T2, and the relationship between T1 and T2 satisfies: 0.2T1≤T2≤T1.

5. The battery according to any one of claims 1-4, wherein, The storage cavity further includes a second wall surrounding the edge connected to the first wall. The thinned area of ​​the first wall includes a first heat-sealing layer, a first metal layer, and a first outer layer stacked together. The second wall includes a second heat-sealing layer, a second metal layer, and a second outer layer stacked together. The thickness of the first heat-sealing layer is less than the thickness of the second heat-sealing layer. The first surface is in contact with the first heat-sealing layer.

6. The battery according to claim 5, wherein, The thickness of the first heat-sealing layer is H, and the thickness of the second heat-sealing layer is G. The relationship between H and G satisfies: H < 0.5G.

7. The battery according to any one of claims 1-4, wherein, The storage cavity further includes a second wall surrounding the edge connected to the first wall. The thinned area of ​​the first wall includes a first metal layer and a first outer layer stacked together. The second wall includes a second heat-sealing layer, a second metal layer and a second outer layer stacked together. The first surface is in contact with the first metal layer.

8. The battery according to claim 1, wherein, Along the width direction of the positive electrode sheet, the first surface is also provided with the insulating layer.

9. The battery according to claim 1 or 8, wherein, The positive electrode and the negative electrode are stacked and wound to form the battery cell. The positive electrode includes a first segment and a second segment that are connected to each other. The end of the first segment away from the second segment is the winding end point of the positive electrode. The end of the second segment away from the first segment is the winding start point of the positive electrode. At least a portion of the first segment forms the abutment portion.

10. The battery according to claim 9, wherein, Along the width direction of the positive electrode sheet, the insulating layer is also provided on both sides of the second segment.

11. The battery of claim 1 or 8, wherein, Multiple positive and negative electrodes are provided. Multiple positive and negative electrodes are stacked alternately to form the battery cell. The positive electrode includes a first electrode and a second electrode. Two first electrodes are located on the outermost side of the battery cell in the thickness direction. The second electrode is located between two adjacent negative electrodes. The first electrode forms the abutment portion.

12. The battery according to claim 11, wherein, Along the width direction of the positive electrode, the insulating layer is also provided on both sides of the second electrode.

13. An electrical appliance, wherein, It includes a main body of an electrical device and a battery as described in any one of claims 1 to 12, wherein the battery is installed in the main body of the electrical device for supplying power to the main body of the electrical device.

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