Single battery, battery pack and electric device

Abstract

This application discloses a single-cell battery, a battery pack, and an electrical device. The single-cell battery includes an encapsulation structure and an electrode assembly. The encapsulation structure has a accommodating cavity, and the electrode assembly is located within the accommodating cavity. The electrode assembly includes a positive electrode sheet, a negative electrode sheet, and a separator spaced between them. The positive electrode sheet has a first direction X and includes a positive current collector, an insulating layer, and a positive active material layer. The negative electrode sheet includes a negative current collector. The positive current collector includes a connected positive electrode body and a positive electrode tab, and the negative current collector includes a connected negative electrode body and a negative electrode tab. On a plane perpendicular to the first direction X, the orthographic projection of the positive electrode body lies within the orthographic projection of the negative electrode body. A first inner peripheral region of the first surface of the positive electrode body has a positive active material layer, and at least a portion of the first outer peripheral region of the first surface has an insulating layer. The single-cell battery, battery pack, and electrical device of this application can reduce the risk of short circuits and improve the reliability of the single-cell battery.

Description

Technical Field

[0001] This application relates to the field of electrochemical technology, specifically to a single cell, a battery pack, and an electrical device. Background Technology

[0002] In the field of electrochemical technology, electrode assemblies include a positive electrode, a negative electrode, and a separator. The separator is located between the positive and negative electrodes and is used to ensure ion transport between the positive and negative electrodes while preventing direct contact between them and thus avoiding a short circuit. However, after the electrodes are cut or die-cut, burrs are easily formed on the edges. The presence of burrs can easily puncture the separator, increasing the risk of a short circuit between the positive and negative electrodes and resulting in poor reliability of the single cell. Summary of the Invention

[0003] This application aims to address at least one of the technical problems existing in the prior art. To this end, this application proposes a single-cell battery that can reduce the risk of short circuits and improve the reliability of the single-cell battery.

[0004] This application also proposes a battery pack having the aforementioned individual cells.

[0005] This application also proposes an electrical device having the aforementioned battery pack.

[0006] A single-cell battery according to an embodiment of this application includes an encapsulation structure and an electrode assembly; The packaging structure has a receiving cavity; The electrode assembly is located within the accommodating cavity. The electrode assembly includes a positive electrode plate, a negative electrode plate, and a separator. The separator is located between the positive electrode plate and the negative electrode plate. The positive electrode plate has a first direction X. The positive electrode plate includes a positive current collector, and the negative electrode plate includes a negative current collector. The positive current collector includes a connected positive electrode body and a positive electrode tab, and the negative current collector includes a connected negative electrode body and a negative electrode tab. On a plane perpendicular to the first direction X, the orthographic projection of the positive electrode body is located within the orthographic projection of the negative electrode body. The positive electrode sheet also includes an insulating layer and a positive electrode active material layer. The positive electrode body includes a first surface, which includes a first inner peripheral region and a first outer peripheral region. The first outer peripheral region surrounds the first inner peripheral region and is located outside the first inner peripheral region. The first inner peripheral region is provided with a positive electrode active material layer, and at least a portion of the first outer peripheral region is provided with an insulating layer.

[0007] The single cell according to the embodiments of this application has at least the following beneficial effects: the orthogonal projection of the positive electrode body is located within the orthogonal projection of the negative electrode body, ensuring that the negative electrode body covers the positive electrode body. Thus, the negative electrode body can provide more sufficient intercalation space for the positive electrode body to extract and insert ions, which is beneficial to improving the lithium plating problem of the single cell and extending the cycle life of the single cell.

[0008] Based on this, the insulating layer covers at least a portion of the first outer peripheral region, encapsulating at least a portion of the burrs formed at the edge of the first outer peripheral region during the cutting or die-cutting process. Thus, the insulating layer forms a physical barrier between the burrs and the separator, effectively reducing the risk of burrs piercing the separator and causing a short circuit between the positive and negative electrodes, thereby improving the reliability and safety of the single-cell battery.

[0009] According to some embodiments of this application, the positive electrode sheet further has a second direction Y perpendicular to the first direction X, the first outer peripheral region includes a first edge region and a second edge region spaced apart along the second direction Y, an insulating layer is disposed in the first edge region, and / or, an insulating layer is disposed in the second edge region.

[0010] According to some embodiments of this application, the electrode assembly is a wound structure, and the positive electrode sheet also has a second direction Y perpendicular to the first direction X. The second direction Y is the width direction of the positive electrode sheet. The first outer peripheral region includes a first edge region and a second edge region that are spaced apart along the second direction. Along the second direction Y, one side of the negative electrode body is flush with the side of the first edge region away from the second edge region, and the other side protrudes from the second edge region. An insulating layer is disposed in the second edge region, and the positive electrode tab is connected to the side of the second edge region away from the positive electrode active material layer along the second direction Y.

[0011] According to some embodiments of this application, the positive electrode body further includes a second surface, which is disposed opposite to the first surface along a first direction. The second surface includes a second inner peripheral region and a second outer peripheral region, with the second outer peripheral region surrounding the second inner peripheral region and located outside the second inner peripheral region. The second inner peripheral region is provided with a positive electrode active material layer, and at least a portion of the second outer peripheral region is provided with an insulating layer, wherein the insulating layer includes an inner side close to the positive electrode active material layer, and the inner side of the insulating layer is connected to the positive electrode active material layer.

[0012] According to some embodiments of this application, the insulating layer at least partially overlaps with the positive electrode active material layer in the first direction X.

[0013] According to some embodiments of this application, along the first direction X, the absolute value of the difference between the size of the positive electrode active material layer 312 and the size of the insulating layer 313 is 15um to 90um.

[0014] According to some embodiments of this application, the insulating layer comprises inorganic particles and a binder.

[0015] According to some embodiments of this application, the inorganic particles include at least one of boehmite and alumina.

[0016] According to some embodiments of this application, the positive electrode sheet has a second direction Y perpendicular to the first direction X, the first outer peripheral region includes a second edge region, an insulating layer is disposed in the second edge region, the positive electrode tab is connected to the side of the second edge region away from the positive electrode active material layer along the second direction, the extension dimension of the insulating layer along the second direction Y is W1, and the extension dimension of the positive electrode body along the second direction Y is W2, satisfying that: the ratio of W1 to W2 is in the range of 1% to 10%.

[0017] According to some embodiments of this application, the packaging structure includes a housing and a top cover assembly. The top cover assembly includes a top cover body, which is connected to the housing and together with the housing forms an accommodating cavity. Positive and negative electrode posts are spaced apart on the top cover body. Along the first direction X, the top cover body has a third surface facing away from the electrode assembly. The positive electrode also has a third direction Z perpendicular to the first direction X. The electrode assembly includes an electrode body and a positive electrode tab and / or a negative electrode tab connected to the electrode body and close to the top cover body. The positive electrode tab contacts and is connected to the positive electrode post, and the negative electrode tab contacts and is connected to the negative electrode post. The positive electrode body, the separator, and the negative electrode body are stacked along the first direction X and wound along the third direction Z to form the electrode body. The electrode body has a fourth surface close to the top cover assembly. The positive electrode also has a second direction perpendicular to the first direction X, and along the second direction Y, the distance between the third surface and the fourth surface is D1, satisfying: .

[0018] According to some embodiments of this application, the separator includes a base membrane and an adhesive layer. Along a first direction X, at least one side of the base membrane is provided with an adhesive layer, which is bonded to at least one of the positive electrode and the negative electrode.

[0019] According to some embodiments of this application, the single cell also includes a positive electrode post and a negative electrode post; The positive terminal is connected and passes through the encapsulation structure, and the positive tab contacts and connects with the positive terminal; And / or, the negative terminal is connected and passes through the package structure, and the negative terminal tab contacts and connects with the negative terminal.

[0020] According to some embodiments of this application, the positive electrode tab includes a positive electrode connection portion, which is welded to the positive electrode post to form a positive electrode solder area. The electrode assembly also includes a first protective layer, which is connected to the side of the positive electrode connection portion away from the positive electrode post and covers the positive electrode solder area. And / or, the negative electrode tab includes a negative electrode connection portion, which is welded to the negative electrode post to form a negative electrode solder area. The electrode assembly also includes a second protective layer, which is connected to the side of the negative electrode connection portion away from the negative electrode post and covers the negative electrode solder area.

[0021] According to some embodiments of this application, the positive electrode post includes a first connection surface near the electrode assembly, the area of ​​the first connection surface is S1, and the area of ​​the positive electrode solder area is S2, satisfying that: the ratio of S2 to S1 is in the range of 2% to 50%; And / or, the negative electrode post includes a second connection surface near the electrode assembly, the area of ​​the second connection surface is S3, and the area of ​​the negative electrode solder area is S4, satisfying that the ratio of S4 to S3 is in the range of 2% to 50%.

[0022] According to some embodiments of this application, the positive electrode post includes a first connecting surface near the electrode assembly, the first connecting surface extends along a first direction X, the positive electrode tab is bent and includes a positive electrode connecting portion away from the positive electrode body, the positive electrode connecting portion extends along the first direction X and is connected to the first connecting surface. And / or, the negative electrode post includes a second connection surface near the electrode assembly, the second connection surface extending along a first direction X, the negative electrode tab being bent and including a negative electrode connection portion at one end away from the negative electrode body, the negative electrode connection portion extending along the first direction X, and the negative electrode connection portion being connected to the second connection surface.

[0023] According to some embodiments of this application, the electrode assembly further includes a third protective layer, the positive electrode tab includes a positive electrode tab body and a positive electrode connection portion connected together, the positive electrode tab body is connected to the positive electrode body, the positive electrode connection portion contacts and connects to the positive electrode post, and at least a portion of the surface of the positive electrode tab body is covered with the third protective layer. And / or, the electrode assembly further includes a fourth protective layer, the negative electrode tab includes a connected negative electrode tab body and a negative electrode connection portion, the negative electrode tab body is connected to the negative electrode body, the negative electrode connection portion contacts and connects to the negative electrode post, and at least a portion of the surface of the negative electrode tab body is covered with the fourth protective layer.

[0024] The battery pack according to the embodiments of this application includes a plurality of individual batteries as described in any of the above embodiments.

[0025] The battery pack according to the embodiments of this application has at least the following beneficial effects: the battery pack is composed of the above-mentioned individual cells connected in series and / or in parallel. The reliability of the individual cells reduces the overall short-circuit risk of the battery pack, making the battery pack safer and more reliable.

[0026] The electrical equipment according to the embodiments of this application includes the battery pack in any of the above embodiments.

[0027] The electrical equipment according to the embodiments of this application has at least the following beneficial effects: by adopting the above-mentioned battery pack, the battery pack is safer and more reliable, and the battery pack can continuously and stably provide power to the electrical equipment, thereby ensuring the stability of continuous operation of the electrical equipment.

[0028] 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

[0029] The present application will be further described below with reference to the accompanying drawings and embodiments, wherein: Figure 1 This is a first-view schematic diagram of the positive electrode sheet according to an embodiment of this application; Figure 2 for Figure 1 Sectional view at point AA; Figure 3 This is a first-view schematic diagram of the positive current collector in an embodiment of this application; Figure 4 This is a schematic diagram of the stacking of the positive electrode, separator, and negative electrode in an embodiment of this application; Figure 5 for Figure 4 Sectional view at point BB; Figure 6 This is a schematic diagram of the structure of a single battery cell according to an embodiment of this application; Figure 7 for Figure 6 Sectional view at point CC.

[0030] Figure 8 for Figure 7 A magnified view of a portion of point D in the middle; Figure 9 This is a cross-sectional view of a single cell according to another embodiment of this application; Figure 10 This is a cross-sectional view of a single cell according to another embodiment of this application.

[0031] Reference numerals: encapsulation structure 100, housing 110, accommodating cavity 111, top cover assembly 120, top cover body 121, third surface 1211; Positive terminal 210, first connecting surface 211, negative terminal 220, second connecting surface 221; Electrode assembly 300, positive electrode sheet 310, positive electrode current collector 311, positive electrode body 3111, first surface 3112, first inner peripheral region 3113, first outer peripheral region 3114, first edge region 3115, second edge region 3116, second surface 3117, second inner peripheral region 3118, second outer peripheral region 3119, positive electrode active material layer 312, first surface 3121, insulating layer 313, second surface 3131, guide groove; 3132, positive electrode tab; 314, positive electrode connection part; 3141, positive electrode tab body; 3142, electrode body; 315, fourth surface; 3151, negative electrode sheet; 320, negative electrode current collector; 321, negative electrode body; 3211, negative electrode tab; 3212, negative electrode connection part; 3213, negative electrode tab body; 3214, negative electrode active material layer; 322, diaphragm; 330, base film; adhesive layer; 332; First protective layer 410, second protective layer 420, third protective layer 430, fourth protective layer 440. Detailed Implementation

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] The embodiments of this application are described below with reference to the accompanying drawings: refer to Figures 1 to 7 According to an embodiment of this application, a single-cell battery includes a packaging structure 100 and an electrode assembly 300. The packaging structure 100 has a receiving cavity 111, and the electrode assembly 300 is located within the receiving cavity 111. The electrode assembly 300 includes a positive electrode 310, a negative electrode 320, and a separator 330. The separator 330 is located between the positive electrode 310 and the negative electrode 320 to prevent direct contact between the positive electrode 310 and the negative electrode 320. The positive electrode 310 includes a positive current collector 311, and the negative electrode 320 includes a negative current collector 321. The positive current collector 311 includes a connected positive electrode body 3111 and a positive electrode tab 314, and the negative current collector 321 includes a connected negative electrode body 3211 and a negative electrode tab 3212. The positive electrode 310 has a first direction X. On a plane perpendicular to the first direction X, the orthographic projection of the positive electrode body 3111 is located within the orthographic projection of the negative electrode body 3211. The 10 also includes an insulating layer 313 and a positive electrode active material layer 312. The positive electrode body 3111 includes a first surface 3112 along the first direction X. The first surface 3112 includes a first inner peripheral region 3113 and a first outer peripheral region 3114. The first outer peripheral region 3114 surrounds the first inner peripheral region 3113 and is located outside the first inner peripheral region 3113. The first inner peripheral region is provided with the positive electrode active material layer 312, and at least a portion of the first outer peripheral region 3114 is provided with the insulating layer 313. The insulating layer 313 can form a physical barrier between the burr and the separator 330, effectively reducing the risk of short circuit caused by the burr piercing the separator 330, and improving the reliability and safety of the single cell.

[0038] Specifically, the electrode assembly 300 can be a wound structure or a stacked structure. Taking the wound structure of the electrode assembly 300 as an example, the positive electrode 310 has a wound state and an unfolded state. The first direction X can be the thickness direction of the positive electrode 310 in the unfolded state, the second direction Y can be the width direction of the positive electrode 310 in the unfolded state, and the third direction Z can be the length direction of the positive electrode 310 in the unfolded state. The first direction X, the second direction Y, and the third direction Z are arranged perpendicular to each other. In the unfolded state, the positive electrode 310 is stacked on the separator 330 and the negative electrode 320 along the first direction X, and wound along the second direction Y as the axial direction, so that the electrode assembly 300 forms a wound structure, and the positive electrode 310 switches from the unfolded state to the wound state. The positive electrode 310 also includes a positive electrode active material layer 312. At least a portion of the first inner peripheral region 3113 is coated with the positive electrode active material layer 312, and a portion of the first outer peripheral region 3114 may also be coated with the positive electrode active material layer 312. The negative electrode 320 includes a negative electrode current collector 321 and a negative electrode active material layer 322. The negative electrode 320 also has an unfolded state. In the unfolded state, the negative electrode body 3211 includes a third and a fourth opposing surface along the first direction X. At least one of the third and fourth surfaces is provided with the negative electrode active material layer 322. Alternatively, it can be understood that the negative electrode current collector 321 is provided with the negative electrode active material layer 322 at least on the side facing the positive electrode current collector 311.

[0039] It should be noted that the arrangement of the insulating layer 313 can be selected according to actual needs. In one embodiment, along the first direction X, the insulating layer 313 is disposed on the first surface 3112 of the positive electrode body 3111 and covers at least a portion of the outer peripheral area of ​​that surface. In another embodiment, the positive electrode body 3111 includes a first surface 3112 and a second surface 3117 disposed opposite to each other along the first direction X. The first surface 3112 includes a first outer peripheral area 3114, and the second surface includes a second outer peripheral area 3119. At least a portion of the first outer peripheral area 3114 is provided with the insulating layer 313, and at least a portion of the second outer peripheral area 3119 is provided with the insulating layer 313.

[0040] Regarding the coverage area, taking the first surface 3112 with an insulating layer 313 as an example, the first outer peripheral area 3114 of the first surface 3112 includes a first edge area 3115 and a second edge area 3116 opposite each other along the second direction Y, and two side edge areas opposite each other along the third direction Z. The insulating layer 313 can cover one side edge area of ​​the first outer peripheral area 3114, or it can simultaneously cover two, three, or four side edge areas. For example, the insulating layer 313 can cover the two side edge areas opposite each other along the second direction Y, or cover the two side edge areas opposite each other along the third direction Z, or simultaneously cover all four side edge areas. In addition, the insulating layer 313 can also only cover a part of one side edge area within the first surface 3112, or cover multiple side edge areas within the first surface 3112, with each side edge area partially covered.

[0041] Regarding the positional relationship of the coverage, taking the first surface 3112 with an insulating layer 313 as an example, the side of the insulating layer 313 away from the positive electrode active material layer 312 is flush with the side of the first outer peripheral region 3114 away from the positive electrode active material layer 312. Specifically, it is flush with the outer edge of a single-sided edge region or with the outer edge of multiple-sided edge regions. Alternatively, the edge of the insulating layer 313 may protrude outward relative to the outer peripheral edge of the first surface 3112, specifically, it may be a single-sided or multiple-sided protrusion, so as to at least partially cover the outer peripheral wall of the positive electrode current collector 311, thereby covering the burrs at the edge of the positive electrode current collector 311. It should be noted that the outer peripheral wall refers to the outer surface that extends circumferentially around a three-dimensional structure with thickness. For example, the outer peripheral wall of the positive electrode current collector 311 is a side wall that surrounds itself, and this side wall is the outer surface.

[0042] In one example, both the first surface 3112 and the second surface 3117 of the positive electrode body 3111 are provided with an insulating layer 313. The insulating layer 313 on the first surface 3112 protrudes from the outer edge of the outer peripheral area of ​​the first surface 3112, and the insulating layer 313 on the second surface 3117 protrudes from the outer edge of the outer peripheral area of ​​the second surface 3117. The insulating layer 313 on the first surface 3112 is connected to the insulating layer 313 on the second surface 3117 to cover the outer peripheral wall of the positive electrode current collector 311.

[0043] In this application, Figure 3 The dashed lines in the diagram are only used to indicate the division of the first inner perimeter region 3113 and the first outer perimeter region 3114, and do not represent the physical structure.

[0044] refer to Figures 1 to 7 In some embodiments, the positive electrode 310 also has a second direction Y perpendicular to the first direction X, and the first peripheral region 3114 includes a first edge region 3115 and a second edge region 3116 spaced apart along the second direction Y. An insulating layer 313 is disposed in the first edge region 3115, and / or the insulating layer 313 is disposed in the second edge region 3116.

[0045] Specifically, on a plane perpendicular to the first direction, the orthographic projection of the positive electrode body 3111 lies within the orthographic projection of the negative electrode body 3211, that is, the edge of the negative electrode body 3211 along the second direction Y bulges outward relative to the edge of the positive electrode body 3111 along the second direction Y. The electrode assembly 300 can be a stacked structure or a wound structure. Taking the electrode assembly 300 as a wound structure as an example, when the positive electrode sheet 310 is in the unfolded state, the first direction X is the thickness direction of the positive electrode sheet 310, the second direction Y is the width direction of the positive electrode sheet 310, and the third direction Z is the length direction of the positive electrode sheet 310. The first direction X, the second direction Y, and the third direction Z are all perpendicular to each other. The positive electrode 310, separator 330, and negative electrode 320 are stacked along a first direction and then wound along a third direction Z to form a wound structure. The first outer peripheral region 3114 and the second outer peripheral region 3119 each include a first edge region 3115 and a second edge region 3116 opposite each other along a second direction Y, and also include a third edge region and a fourth edge region opposite each other along a third direction Z. The first edge region 3115 and the second edge region 3116 extend along the third direction Z. When the positive electrode 310 is in the wound state, the first edge region 3115 and the second edge region 3116 are located above or below the electrode assembly 300 along the second direction Y, and extend continuously along the winding direction. Their extension length is much greater than the extension length of the third and fourth edge regions along the second direction Y. Therefore, the first edge region 3115 and the second edge region 3116 are the main distribution areas of burrs in the wound structure.

[0046] Based on this, this application provides an insulating layer 313 on the side of the positive electrode current collector 311. The insulating layer 313 covers at least one of the first edge region 3115 and the second edge region 3116 along the first direction X, thereby covering the main distribution area of ​​burrs and forming an effective physical barrier between the burrs and the separator 330, reducing the risk of short circuit between the positive and negative electrodes. At the same time, minimizing the amount of insulating layer 313 helps to balance the energy density of the single cell.

[0047] refer to Figure 1 and Figure 2 In other embodiments, the insulating layer 313 has a flow guide groove 3132 on the surface opposite to the positive electrode current collector 311 along the first direction X. The flow guide groove 3132 extends along the second direction Y and / or extends along the third direction Z. The depth of the flow guide groove 3132 along the first direction X is less than the thickness of the insulating layer 313. The width of the flow guide groove 3132 can be set according to actual needs. During the electrolyte filling process of a single battery, the flow guide groove 3132 is used to guide the flow of electrolyte to promote the wetting of the electrode assembly 300 by the electrolyte.

[0048] refer to Figures 1 to 7In some embodiments, the electrode assembly 300 is a wound structure. When the positive electrode 310 is in the unfolded state, the first direction is the thickness direction of the positive electrode 310, and the second direction Y is the width direction of the positive electrode 310. The negative electrode 320 is stacked with the positive electrode 310 along the first direction X. The first peripheral region 3114 includes a first edge region 3115 and a second edge region 3116 spaced apart along the second direction Y. Along the second direction, one side of the negative electrode body 3211 is flush with the side of the first edge region 3115 away from the second edge region 3116, and the other side protrudes from the second edge region 3116. The insulating layer 313 is disposed on the second edge region 3116. It can completely cover the second edge region 3116 along the first direction X, or it can partially cover the second edge region 3116 along the first direction X. The positive electrode tab 314 is connected to the side of the second edge region 3116 away from the positive electrode active material layer 312 along the second direction Y. The negative electrode 320 protrudes from the second edge region 3116, ensuring that the negative electrode active material layer 322 covers the positive electrode active material layer 312 to improve lithium plating. The insulating layer 313 in the second edge region 3116 isolates the burrs at the edge of the second edge region 3116 from the negative electrode 320, taking into account both the cycle performance and safety of the single cell.

[0049] Specifically, the encapsulation structure 100 includes a housing 110 and a top cover assembly 120. The housing 110 includes a bottom wall with an opening on one side opposite to the bottom wall along the second direction Y. The top cover assembly 120 is connected to the housing 110, specifically to the side of the housing 110 with the opening. The two together form a receiving cavity 111. The electrode assembly 300 is located within the receiving cavity 111. Along the second direction Y, a first edge region 3115 is located near the bottom wall of the housing 110, and a second edge region 3116 is located near the opening of the housing 110. The encapsulation structure 100 is positioned along... The second direction Y is vertically placed, and the lower side of the negative electrode 320 is flush with the lower side of the first edge region 3115. This can make more effective use of the space near the bottom wall of the housing 110, which is conducive to improving the utilization rate of the internal space of the housing 110 and ensuring energy density. The upper side of the negative electrode 320 protrudes from the second edge region 3116, so that the upper side of the negative electrode 320 exceeds the positive electrode 310. This ensures that the negative electrode active material layer 322 covers the positive electrode active material layer 312 while leaving a margin, which is conducive to improving lithium plating and increasing the cycle life of the single cell.

[0050] It should be noted that the first edge region 3115 is located near the bottom wall of the casing 110. This region is rigidly constrained by the casing 110, resulting in small electrode expansion displacement during charging and discharging, stable stress in the separator 330, and minimal impact from welding and other processes during manufacturing. Therefore, the risk of burrs at the first edge region 3115 piercing the separator 330 is low. However, the second edge region 3116 is located near the opening of the casing 110. This region involves electrode tab welding, hot pressing, and other processes during manufacturing, leading to concentrated mechanical and thermal stress. Simultaneously, the electrode expansion displacement is significant during charging and discharging, resulting in more pronounced dynamic stress on the separator 330. This increases the risk of burrs piercing the separator 330. This application addresses this by providing an insulating layer 313 in the higher-risk second edge region 3116, enclosing the burrs at the second edge region 3116 of the positive electrode current collector 311 within the insulating layer 313. This improves the safety of the individual battery while reducing the space occupied by the insulating layer 313, thus balancing the energy density of the individual battery.

[0051] refer to Figures 1 to 7 In another example, the first direction X is the thickness direction of the positive electrode sheet 310 in its unfolded state. The positive electrode active material layer 312 is disposed on the first surface 3112 and / or the second surface 3117 of the positive electrode body 3111. Taking the first surface 3112 as an example, the positive electrode active material layer 312 covers a portion of the first surface 3112 along the first direction X. The outer peripheral wall of the positive electrode active material layer 312 is spaced apart from the outer peripheral wall of the positive current collector 311 along the second direction Y, that is, the positive electrode active material layer 312 does not extend to the first surface 3112. At the location of the outer peripheral region, the first surface 3112 of the positive electrode body 3111 has an exposed area. Specifically, the side of the first surface 3112 adjacent to the first edge region 3115 can be an exposed empty foil area. The first surface 3112 is the side of the positive electrode current collector 311 facing the negative electrode sheet 320. The side of the negative electrode current collector 321 facing the positive electrode current collector 311 is coated with a negative electrode active material layer 322. The negative electrode active material layer 322 covers the negative electrode current collector 321 along the first direction X, and the outer peripheral wall of the negative electrode active material layer 322 is flush with the outer peripheral wall of the negative electrode current collector 321. Thus, based on the fact that the side of the negative electrode sheet 320 along the second direction Y is flush with the outer edge of the first edge region 3115, by setting an empty foil area in the vicinity of the first edge region 3115, it is beneficial to improve the lithium plating problem in the area around the first edge region 3115 and improve the cycle performance of the single cell.

[0052] refer to Figure 1 and Figure 2In some embodiments, the positive electrode body 3111 further includes a second surface 3117, which is disposed opposite to the first surface 3112 along a first direction X. The second surface 3117 includes a second inner peripheral region 3118 and a second outer peripheral region 3119, with the second outer peripheral region 3119 surrounding the second inner peripheral region 3118 and located outside the second inner peripheral region 3118. The second inner peripheral region 3118 is provided with a positive electrode active material layer 312, and at least a portion of the second outer peripheral region 3119 is provided with an insulating layer 313. The insulating layer 313 includes an inner side close to the positive electrode active material layer 312, and the inner side of the insulating layer 313 is connected to the positive electrode active material layer 312. Specifically, the connection method can be that the outer peripheral wall of the positive electrode active material layer 312 is connected to the inner side of the insulating layer 313, or the positive electrode active material layer 312 and the insulating layer 313 overlap. By connecting the insulating layer 313 to the positive electrode active material layer 312, burr protection is achieved while improving the structural stability of the coating edge, enabling the single cell to balance structural stability and safety.

[0053] Specifically, the positive electrode body 3111 includes a first surface 3112 and a second surface 3117 opposite each other along the first direction X. Taking the first surface 3112 coated with a positive electrode active material layer 312 as an example, the first peripheral region 3114 includes a first edge region 3115 and a second edge region 3116 opposite each other along the second direction Y. The positive electrode active material layer 312 is coated on the first surface 3112 and partially covers the first surface 3112. Along the second direction Y, the outer peripheral side of the positive electrode active material layer 312 is spaced apart from the outer peripheral side of the positive electrode body 3111, so that at least a partially empty foil region is formed in the first edge region 3115 and / or the second edge region 3116. The insulating layer 3 13 is coated on the empty foil area and at least partially covers the first edge area 3115 and / or the second edge area 3116. In one connection method, the inner side of the insulating layer 313 is connected to the side of the positive electrode active material layer 312 closest to the insulating layer 313. In another connection method, in addition to the insulating layer 313 being connected to the positive electrode active material layer 312, the insulating layer 313 also overlaps the positive electrode active material layer 312 at least partially along the first direction X. The connection between the insulating layer 313 and the positive electrode active material layer 312 completely covers the surface of the positive electrode current collector 311, avoiding the existence of an empty foil area and improving the space utilization of the surface of the positive electrode current collector 311. At the same time, the connection between the insulating layer 313 and the positive electrode active material layer 312 enhances the structural stability of the connecting edge between the insulating layer 313 and the positive electrode active material layer 312.

[0054] refer to Figure 2 In some embodiments, the insulating layer 313 at least partially overlaps with the positive electrode active material layer 312 in the first direction X, which is beneficial to improving the stability of the coating on the surface of the positive electrode current collector 311.

[0055] Specifically, the insulating layer 313 and the positive electrode active material layer 312 are stacked along the first direction X. In one embodiment, at least a portion of the insulating layer 313 is located on the side of the positive electrode active material layer 312 facing away from the positive electrode current collector 311 (see reference). Figure 2 The upper side of the positive electrode current collector 311 can be an insulating layer 313 stacked on top of the positive electrode active material layer 312 along the first direction X, covering a part of the positive electrode active material layer 312. Due to the coating process, the positive electrode active material layer 312 usually has a region where the thickness gradually decreases at the edge where the outer peripheral wall is located. By covering this region with the insulating layer 313, the thickness of the exposed positive electrode active material layer 312 can be made more uniform, improving the uniformity of current distribution.

[0056] In another embodiment, at least a portion of the insulating layer 313 is located on the side of the positive electrode active material layer 312 near the positive electrode current collector 311 (see reference). Figure 2 The lower side of the positive electrode current collector 311 can be an insulating layer 313 stacked along the first direction X below the positive electrode active material layer 312. At least a portion of the insulating layer 313 is located between the positive electrode active material layer 312 and the positive electrode current collector 311. The positive electrode active material layer 312 covers the surface of the insulating layer 313 away from the positive electrode current collector 311, so that the coating area of ​​the positive electrode active material layer 312 on the positive electrode current collector 311 is larger, which is beneficial to improving the energy density.

[0057] It should be noted that "at least part" includes "all". It can mean that a part of the insulating layer 313 is located between the positive electrode active material layer 312 and the positive electrode current collector 311, or that the entire insulating layer 313 is located between the positive electrode active material layer 312 and the positive electrode current collector 311.

[0058] refer to Figure 1 and Figure 2In some embodiments, the absolute value of the difference between the size of the positive electrode active material layer 312 and the size of the insulating layer 313 along the first direction X is 15µm to 90µm. Setting the size difference between the positive electrode active material layer 312 and the insulating layer 313 along the first direction X within this range ensures that the thickness of the positive electrode active material layer 312 and the insulating layer 313 on the same side of the positive electrode body 3111 along the first direction X are substantially the same. The flat surface on the same side of the positive electrode sheet 310 facilitates a tight fit between the separator 330 and the positive electrode sheet 310, thereby improving the compactness of the single-cell battery and increasing the battery's energy density. It should be noted that, taking the first surface 3112 of the positive electrode body 3111 as an example, the first surface 3112 is coated with an insulating layer 313 and a positive electrode active material layer 312. The first surface 3121 is the surface of the exposed portion of the positive electrode active material layer 312. If the insulating layer 313 covers a portion of the positive electrode active material layer 312, the positive electrode active material layer 312 within the area covered by the insulating layer 313 should be excluded. The position of the positive electrode active material layer 312 along the first direction X on the first surface 3112 should be measured. The measurement is performed by selecting multiple positions at different locations in this area. The average value of measurements taken at each point is used as the dimension of the positive electrode active material layer 312 along the first direction X. Similarly, the second surface 3131 is the surface of the exposed portion of the insulating layer 313. If the positive electrode active material layer 312 covers a part of the insulating layer 313, the insulating layer 313 in the area covered by the positive electrode active material layer 312 should be excluded. The position of the insulating layer 313 along the first direction X on the first surface 3112 should be measured. The measurement is done by selecting multiple points at different positions in the area and taking the average value, which is used as the dimension of the insulating layer 313 along the first direction X. For example, along the first direction X, the absolute value of the difference between the size of the positive electrode active material layer 312 and the size of the insulating layer 313 can be 15um, 16um, 17um, 18um, 19um, 20um, 30um, 40um, 50um, 60um, 70um, 80um, 81um, 82um, 83um, 84um, 85um, 86um, 87um, 88um, 89um, 90um, or within the range of any two of the above values.

[0059] refer to Figures 1 to 7 In some embodiments, the insulating layer 313 comprises inorganic particles and a binder. Specifically, the inorganic particles may be ceramic materials, such as alumina, zirconium oxide, silicon dioxide, or boehmite, to improve insulation performance and mechanical strength. The binder may be polymer materials, such as polyvinylidene fluoride, styrene-butadiene rubber, or polyacrylate, to bond the inorganic particles together and fix the insulating layer 313 to the surface of the positive electrode current collector 311.

[0060] It should be noted that the inorganic particles have high hardness and high insulation properties, enabling them to form a skeletal structure in the insulating layer 313, effectively preventing punctures from burrs and providing reliable electrical insulation. The binder tightly bonds the inorganic particles, making the insulating layer 313 a continuous and dense coating, while also enhancing the adhesion strength between the insulating layer 313 and the positive current collector 311.

[0061] refer to Figures 1 to 7 In some embodiments, the inorganic particles include at least one of boehmite and alumina. The positive electrode current collector 311 can be made of aluminum foil. A binder mixed with boehmite and / or alumina is coated on the surface of the positive electrode current collector 311 to form an insulating layer 313. Compared to the positive electrode current collector 311, boehmite has lower hardness, and using boehmite can flexibly cover the burrs on the edge of the positive electrode current collector 311. Moreover, boehmite has a lower specific gravity, which is beneficial to improving the energy density of the single cell. Alumina has high temperature resistance, which is beneficial to improving the thermal stability of the single cell. Furthermore, alumina powder has good wettability, which is beneficial to improving the liquid absorption and retention capacity of the single cell.

[0062] refer to Figures 1 to 7 In some embodiments, the positive electrode 310 has a second direction Y perpendicular to the first direction X, the insulating layer 313 extends along the second direction Y by an dimension of W1, and the positive electrode body 3111 extends along the second direction Y by an dimension of W2, satisfying that the ratio of W1 to W2 is in the range of 1% to 10%, which is beneficial to balance the energy density and safety protection performance of the single cell.

[0063] For example, the ratio of W1 to W2 can be 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, or 10%, or fall within the range of any two of the above values.

[0064] It should be noted that when measuring W1 and W2, the individual battery is disassembled, and the electrode assembly 300 is removed after disassembly. The positive electrode 310 is then separated, leaving it in an unfolded state. The positive electrode 310 includes a positive current collector 311, which comprises a connected positive electrode body 3111 and a positive electrode tab 314. A laser beam is used to scan the edge of the positive electrode body 3111, and W2 is calculated by measuring the time difference or phase difference between the laser beam emission and reception. Alternatively, an image of the positive electrode 310 can be acquired, and the edge position of the positive electrode body 3111 can be analyzed using an image processing algorithm to calculate the width of the positive electrode body 3111. W1 can be measured using the high-magnification function of an optical microscope to observe the edge position of the insulating layer 313, and then the coating width can be measured using a scale on the microscope or image processing software.

[0065] refer to Figures 1 to 8In some embodiments, the encapsulation structure 100 includes a housing 110 and a top cover assembly 120. The top cover assembly 120 includes a top cover body 121, which is connected to the housing 110 and together with the housing 110 forms an accommodating cavity 111. A positive electrode post 210 and a negative electrode post 220 are spaced apart on the top cover body 121. Along the first direction X, the top cover body 121 has a third surface 1211 facing away from the electrode assembly 300. The positive electrode 310 also has a third surface perpendicular to the first direction X. In the Z direction, the electrode assembly 300 includes an electrode body 315 and a positive electrode tab 314 and / or a negative electrode tab 3212 connected to the electrode body 315 and close to the top cover body 121. The positive electrode body 3111, the diaphragm 330, and the negative electrode body 3211 are stacked along the first direction X and wound along the third direction Z to form the electrode body 315. The electrode body 315 has a fourth surface 3151 close to the top cover assembly 120. Along the second direction Y, the distance between the third surface 1211 and the fourth surface 3151 is D1 (refer to...). Figure 6 ), satisfying: 0 .

[0066] For example, The value can be 0.3, 0.4, 0.5, 0.6, 0.7 or 0.8, or fall within the range of any two of the above values.

[0067] Specifically, the single battery cell includes a positive electrode post 210, which is connected to and passes through the top cover assembly 120. The positive electrode post 210 is insulated from the top cover assembly 120. The top cover assembly 120 includes a top cover body 121, which is a structure in which the top cover assembly 120 is directly connected to the housing 110. The positive current collector 311 includes a positive electrode body 3111 and a positive electrode tab 314 connected to it. The positive electrode tab 314 is directly connected to the positive electrode post 210, and the connection between the negative electrode tab 3212 and the negative electrode post 220 is similar. That is, in this application, the tabs and posts are directly connected without adapter plates. This example limits the connection between the tabs and posts. The lower limit value, that is, at least one of the three factors—W1 being too small, W2 being too large, and D1 being too large—is limited by restricting... The upper limit is set at least to restrict one of the following three values: W1 being too large, W2 being too small, and D1 being too small. Therefore, by linking W1, W2, and D1 and limiting... The lower and upper limits ensure that the three parameters W1, W2 and D1 are all within a suitable range that balances the energy density and safety of individual cells, which is beneficial to better balance the safety and energy density of individual cells.

[0068] It should be noted that none of the three parameters W1, W2, and D1 can be too large or too small, and W1, W2, and D1 are all pairwise related. Based on the example in this case, 0... The limitation facilitates faster determination of whether each parameter falls within the preferred range. For example, W2 is set according to the size of the individual battery cell. Once the size of the individual battery cell is determined, the value of W2 can be determined. Based on the above embodiment, the ratio range of W1 to W2 is limited to 0.01 to 0.1. Therefore, W1 has a numerical range that adapts to W2. If D1 is too large, then... It will fall below the lower limit. If D1 is too small, then... It will exceed the upper limit, the ratio of W1 to W2, and The range of values ​​for D1 is limited, making the three parameters interrelated and improving the safety and energy density of a single battery cell.

[0069] In some embodiments, 2mm≤W1≤3mm, 20mm≤W2≤300mm, and 5mm≤D1≤10mm can better improve the safety and energy density of a single battery cell.

[0070] Specifically, for example, the value of W1 can be 2mm, 2.1mm, 2.2mm, 2.3mm, 2.4mm, 2.5mm, 2.6mm, 2.7mm, 2.8mm, 2.9mm, 3mm, or within the range of any two of the above values.

[0071] Specifically, for example, the value of W2 can be 20mm, 30mm, 40mm, 50mm, 60mm, 70mm, 80mm, 90mm, 100mm, 110mm, 120mm, 130mm, 140mm, 150mm, 160mm, 170mm, 180mm, 190mm, 200mm, 210mm, 220mm, 230mm, 240mm, 250mm, 260mm, 270mm, 280mm, 290mm, 300mm, or within the range of any two of the above values.

[0072] Specifically, for example, the value of D1 can be 5mm, 6mm, 7mm, 8mm, 9mm, 9.1mm, 9.2mm, 9.3mm, 9.4mm, 9.5mm, 9.6mm, 9.7mm, 9.8mm, 9.9mm, 9.91mm, 9.95mm, 9.98mm, or within the range of any two of the above values.

[0073] refer to Figures 1 to 5In some embodiments, the separator 330 includes a base film 331 and an adhesive layer 332. Along the first direction X, at least one side of the base film 331 is provided with the adhesive layer 332, which is bonded to at least one of the positive electrode 310 and the negative electrode 320. Bonding and fixing the separator 330 to the electrode using the adhesive layer 332 helps to further improve the structural stability of the electrode assembly 300, thereby reducing the risk of damage to the separator 330 due to relative movement between the electrode and the separator 330.

[0074] Specifically, the base membrane 331 can be a polyolefin porous membrane, such as a polyethylene membrane, a polypropylene membrane, or a composite membrane of both, used to provide mechanical support and ion transport channels, and to provide physical isolation between the positive and negative electrodes. The adhesive layer 332 can be a polymer coating, such as polyvinylidene fluoride, polyacrylate, or polyimide, coated on the surface of the base membrane 331. During battery assembly, the adhesive layer 332 is heated and pressurized to bond with the surfaces of the positive electrode 310 and / or the negative electrode 320, thus forming a fixed connection between the separator 330 and the electrode at the interface. During charge-discharge cycles, the adhesive layer 332 maintains the relative position of the separator 330 and the electrode, effectively preventing relative slippage between the separator 330 and the electrode due to electrode expansion and contraction.

[0075] It should be noted that the adhesive layer 332 enables the diaphragm 330 and the electrode sheet to form an integral structure at the interface. When there are burrs on the edge of the positive current collector 311, the fixed relative position of the diaphragm 330 and the positive electrode sheet 310 keeps the contact point between the burr and the diaphragm 330 constant, avoiding local wear of the diaphragm 330 caused by relative movement. At the same time, the adhesive layer 332 fills the micro gap between the diaphragm 330 and the electrode sheet, improves the interfacial bonding strength, enhances the structural stability of the electrode assembly 300, and helps to suppress the warping deformation of the electrode sheet during the cycle.

[0076] refer to Figures 1 to 7In some embodiments, the single battery cell further includes a positive terminal 210 and a negative terminal 220. The positive terminal 210 is connected to and passes through the encapsulation structure 100. Specifically, the encapsulation structure 100 includes a housing 110 and a top cover assembly 120. The top cover assembly 120 is connected to the housing 110 and forms an accommodating cavity 111. The positive terminal 210 is connected to and passes through the top cover assembly 120. The positive electrode tab 314 contacts and connects to the positive terminal 210. Compared to using an adapter plate... The current connection method between the positive tab 314 and the positive terminal 210 achieves a direct connection between the positive tab 314 and the positive terminal 210, and / or, the negative terminal 220 is connected and passes through the encapsulation structure 100, specifically, the negative terminal 220 is connected and passes through the top cover assembly 120, the positive terminal 210 and the negative terminal 220 are spaced apart, and the negative tab 3212 contacts and connects with the negative terminal 220. Similarly, the connection between the negative tab 3212 and the negative terminal 220 is achieved. Therefore, by directly connecting the positive tab 314 to the positive terminal 210 and the negative tab 3212 to the negative terminal 220, compared with the connection method using an adapter, the production process of the single battery is simplified, space utilization is improved, and thus the energy density of the single battery is increased.

[0077] Specifically, the positive current collector 311 includes a connected positive electrode body 3111 and a positive electrode tab 314. The positive electrode tab 314 is connected to the positive electrode body 3111, and the two can be integrally formed. The positive electrode body 3111 includes a first surface 3112 and a second surface 3117 opposite each other along the first direction X. The first peripheral region 3114 and the second peripheral region 3119 can each include a first edge region 3115 and a second edge region 3116 opposite each other along the second direction Y. The positive electrode tab 314 is located on the side of the positive electrode body 3111 near the second edge region 3116. The top cover assembly 120 is located on the side of the positive electrode body 3111 connected to the positive electrode tab 314. The positive electrode tab 314 is directly connected to the positive electrode post 210, which can save the assembly process of intermediate transfer parts and is beneficial to improve the space utilization rate inside the housing 110.

[0078] Similarly, the negative electrode tab 3212 is directly connected to the negative electrode post 220. For example, along the second direction Y, the positive electrode tab 314 and the negative electrode tab 3212 are provided on the same side of the electrode assembly 300, and the top cover assembly 120 is located on the side of the electrode assembly 300 where the positive electrode tab 314 and the negative electrode tab 3212 are provided. Alternatively, the electrode assembly 300 has a positive electrode tab 314 on one side along the second direction Y, and a negative electrode tab 3212 on the opposite side.

[0079] It should be noted that the connection methods between the tabs and the posts include, but are not limited to, welding, gluing, etc. In addition, there can be multiple positive tabs 314 and multiple negative tabs 3212.

[0080] refer to Figures 1 to 8In some embodiments, the positive electrode tab 314 includes a positive electrode connection portion 3141, which is welded to the positive electrode post 210 to form a positive electrode solder area. The electrode assembly 300 also includes a first protective layer 410, which is connected to the side of the positive electrode connection portion 3141 away from the positive electrode post 210 and covers the positive electrode solder area. Alternatively, the negative electrode tab 3212 includes a negative electrode connection portion 3213, which is welded to the negative electrode post 220 to form a negative electrode solder area. The electrode assembly 300 also includes a second protective layer 420, which is connected to the side of the negative electrode connection portion 3213 away from the negative electrode post 220 and covers the negative electrode solder area. By providing a protective layer to cover the electrode tab solder area, reliable electrical connection between the tab and the post can be ensured while reducing the risk of punctures such as burrs on the electrode tab solder area, which is beneficial to further improving the safety and reliability of the single battery cell.

[0081] Specifically, the positive electrode solder area has structures such as burrs, sharp corners or molten protrusions. The first protective layer 410 is disposed along the second direction Y on the side of the positive electrode connection 3141 away from the positive electrode post 210 and covers the positive electrode solder area along the second direction Y. It is used to prevent the positive electrode solder area from contacting the separator 330 and further reduce the risk of short circuit. Similarly, the second protective layer 420 is used to prevent the negative electrode solder area from contacting the separator 330.

[0082] The first protective layer 410 can be at least one of insulating tape, insulating coating, or insulating film. For example, the insulating tape can be a polyimide tape, which includes a substrate layer and a pressure-sensitive adhesive layer, and is bonded to the surface of the positive electrode connection portion 3141 through the pressure-sensitive adhesive layer, covering the positive electrode soldering area. The insulating coating can be a thin film formed by coating an insulating slurry onto the surface of the positive electrode connection portion 3141 and then curing it. The insulating slurry may include inorganic fillers (such as alumina, boehmite) and binders (such as polyvinylidene fluoride).

[0083] refer to Figures 1 to 7 In some embodiments, the positive electrode post 210 includes a first connection surface 211 near the electrode assembly 300, the area of ​​the first connection surface 211 being S1, and the area of ​​the positive electrode solder area being S2, satisfying that the ratio of S2 to S1 is in the range of 2% to 50%, and / or, the negative electrode post 220 includes a second connection surface 221 near the electrode assembly 300, the area of ​​the second connection surface 221 being S3, and the area of ​​the negative electrode solder area being S4, satisfying that the ratio of S4 to S3 is in the range of 2% to 50%. This is beneficial for balancing welding strength and the safety of the individual battery cells.

[0084] Specifically, for example, the ratio of S2 to S1 can be 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, or 50%, or fall within the range of any two of the above values.

[0085] The ratio of S4 to S3 can be 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, or 50%, or fall within the range of any two of the above values.

[0086] It should be noted that when measuring S1, the top cover assembly 120 is separated from the housing 110, and the positive electrode tab 314 is separated from the positive electrode post 210, so that the first connecting surface 211 of the positive electrode post 210 is exposed. After the first connecting surface 211 is exposed, the first connecting surface 211 is cleaned. If the first connecting surface 211 is circular or square, the area of ​​the first connecting surface 211 can be calculated by measuring the diameter or side length with a vernier caliper. If the first connecting surface 211 is an irregular shape, the surface area of ​​the first connecting surface 211 can be calculated based on the acquired image or the contour of the first connecting surface 211 by an image acquisition device or a contour acquisition device.

[0087] Furthermore, during measurement S2, the positive electrode tab 314 is kept connected to the positive electrode post 210. With the positive electrode tab 314 facing away from the positive electrode post 210, the positive electrode solder area is placed under the optical system of a stereomicroscope or image measuring instrument, and the first connection surface 211 of the positive electrode post 210 is perpendicular to the measurement optical axis. A clear image of the positive electrode solder area is obtained using the CCD lens of the image measuring instrument, ensuring that the solder boundary can be clearly identified, thereby outlining the contour boundary of the positive electrode solder area. The area of ​​the positive electrode solder area is then calculated based on the contour boundary of the positive electrode solder area.

[0088] Similarly, the measurement methods for S1 and S2 can be used to measure S3 and S4. The positive electrode solder area is the molten area formed after the positive electrode connection 3141 is welded to the positive electrode post 210. The lower limit of the ratio of S2 to S1 is set to ensure the connection strength between the positive electrode tab 314 and the positive electrode post 210 and to make the conductivity more reliable. The upper limit of the ratio of S2 to S1 is set to help maintain the structural integrity of the positive electrode tab 314 and the positive electrode post 210, make the conductivity more stable, and effectively reduce the risk of burrs or spatter generated at the edge of the positive electrode solder area damaging the diaphragm 330.

[0089] refer to Figures 4 to 8 In some embodiments, the positive electrode post 210 includes a first connecting surface 211 near the electrode assembly 300. The first connecting surface 211 extends along a first direction X. At least a portion of the first connecting surface 211 is arranged parallel to the first direction X. Alternatively, at least a portion of the first connecting surface 211 is arranged substantially parallel to the first connecting surface 211. "Substantially parallel" can be understood as the first direction X having a small angle with the first connecting surface 211, for example, the angle can be within 10°. The positive electrode tab 314 is bent and includes a positive electrode connection portion 3141 at one end away from the positive electrode body 3111. For example, one end of the positive electrode tab 314 is connected to the positive electrode body 3111, and the other end is provided with the positive electrode connection portion 3141. The positive electrode connection portion 3141 extends along the first direction X and is connected to the first connection surface 211. And / or, the negative electrode post 220 includes a second connection surface 221 near the electrode assembly 300. The second connection surface 221 extends along the first direction X. The negative electrode tab 3212 is bent and includes a negative electrode connection portion 3213 at one end away from the negative electrode body 3211. The negative electrode connection portion 3213 extends along the first direction X and is connected to the second connection surface 221. Similarly, at least a portion of the second connection surface 221 is parallel to the first direction X. The parallelism between the two can be substantially parallel. By setting the tabs to a bent structure, the tabs form a tab connection part that extends in a set direction, which facilitates a reliable connection between the tabs and the pole.

[0090] Specifically, in the unfolded state of the positive electrode 310, the first direction X is the thickness direction of the positive electrode 310, the second direction Y is the width direction of the positive electrode 310, and the third direction Z is the length direction of the positive electrode 310. The positive current collector 311 includes a positive electrode body 3111 and a positive electrode tab 314. The positive electrode tab 314 includes a first positive electrode tab segment and a second positive electrode tab segment. The first positive electrode tab segment extends along the second direction Y. One end of the first positive electrode tab segment is connected to the positive electrode body 3111, and the two can be integrally formed. The other end of the first positive electrode tab segment is connected to the second positive electrode tab segment. The end of the second positive electrode tab segment away from the first positive electrode tab segment is provided with a positive electrode connection portion 3141. The second positive electrode tab segment extends along the first direction X, such that the extension direction of the second positive electrode tab segment is arranged at an angle to the extension direction of the first positive electrode tab segment. For example, the extension direction of the second positive electrode tab segment is parallel to the first connection surface 211. The parallelism can be substantially parallel. For example, the extension direction of the second positive electrode tab segment and the extension direction of the first connection surface 211 have an angle of less than 10°, which facilitates the connection between the two by welding. The negative electrode tab 3212 is similar and will not be described in detail here.

[0091] Therefore, by setting the electrode tabs as a bent structure, making the connecting surface of the electrode tabs basically parallel to the connecting surface of the electrode post, the contact area during welding can be increased, thereby improving welding strength and reliability. At the same time, the bent structure reduces the outward extension length of the electrode tabs in the second direction Y, which is beneficial to improving the space utilization rate inside the housing 110.

[0092] refer to Figures 4 to 10 In some embodiments, the electrode assembly 300 further includes a third protective layer 430. The positive electrode tab 314 includes a connected positive electrode tab body 3142 and a positive electrode connection portion 3141. The positive electrode tab body 3142 is connected to the positive electrode body 3111, and the two can be integrally formed. The positive electrode connection portion 3141 contacts and connects to the positive electrode post 210. At least a portion of the surface of the positive electrode tab body 3142 is covered with the third protective layer 430. Based on the bent configuration of the positive electrode tab 314, the coverage of the positive electrode tab 314 by the third protective layer 430 is beneficial to reduce the bending effect of the positive electrode tab 314. 4. To reduce the risk of bending and puncturing the separator 330, further improving the safety of the single cell; and / or, the electrode assembly 300 also includes a fourth protective layer 440, the negative electrode tab 3212 includes a connected negative electrode tab body 3214 and a negative electrode connection portion 3213, the negative electrode tab body 3214 is connected to the negative electrode body 3211, the negative electrode connection portion 3213 is in contact with and connected to the negative electrode post 220, at least a portion of the surface of the negative electrode tab body 3214 is covered with the fourth protective layer 440, the fourth protective layer 440 is used to reduce the risk of bending and puncturing the separator 330 of the negative electrode tab 3212.

[0093] Specifically, the positive electrode tab 314 is bent, and the third protective layer 430 is a protective layer covering the surface of the positive electrode tab body 3142. The side surface of the positive electrode connection portion 3141 connected to the first connection surface 211 is not covered by the third protective layer 430. The third protective layer 430 is used to prevent the burrs generated by the bending of the positive electrode tab 314 from directly contacting the diaphragm 330 or the electrode assembly 300. If the electrode assembly 300 is also provided with a first protective layer 410, the first protective layer 410 covers the side of the positive electrode connection portion 3141 away from the positive electrode post 210. Specifically, after the positive electrode connection portion 3141 is welded to the first connection surface 211 to form a positive electrode solder area, the first protective layer 410 is covered on the side of the positive electrode connection portion 3141 away from the positive electrode post 210. The first protective layer 410 can be stacked with the third protective layer 430, that is, a part of the third protective layer 430 is located between the first protective layer 410 and the positive electrode connection portion 3141.

[0094] Furthermore, the coverage area of ​​the third protective layer 430 can be selected according to actual needs. For example, it can cover the bending area of ​​the positive electrode body 3111. Similarly, the fourth protective layer 440 covers the surface of the negative electrode body 3214 in the same way to reduce the risk of puncturing the separator 330 when the negative electrode 3212 is bent. Thus, based on the protective layer set on the side of the electrode connection portion away from the electrode post, this application further sets a protective layer on the electrode body. While realizing the direct connection between the electrode and the electrode post during bending, it further reduces the risk of burrs introduced by the bending process, which is beneficial to improving the safety and reliability of the single cell.

[0095] refer to Figures 1 to 10 The battery pack according to the embodiments of this application includes a plurality of individual cells as described in any of the above embodiments. Each individual cell is connected in series and / or in parallel. The individual cells are safe and reliable, which reduces the overall short-circuit risk of the battery pack and makes the battery pack safer and more reliable.

[0096] refer to Figures 1 to 10 The electrical equipment according to the embodiments of this application includes the battery pack in the above embodiments. The battery pack is safe and reliable, and can continuously and stably provide power to the electrical equipment, thereby ensuring the stability of continuous operation of the electrical equipment.

[0097] 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. A single-cell battery, characterized in that, include: The encapsulation structure (100) has a receiving cavity (111); An electrode assembly (300) is located within the accommodating cavity (111). The electrode assembly (300) includes a positive electrode plate (310), a negative electrode plate (320), and a separator (330). The separator (330) is located between the positive electrode plate (310) and the negative electrode plate (320). The positive electrode plate (310) has a first direction (X). The positive electrode plate (310) includes a positive current collector (311). The negative electrode plate (320) includes a negative current collector (321). The positive current collector (311) includes a connected positive electrode body (3111) and a positive electrode tab (314). The negative current collector (321) includes a connected negative electrode body (3211) and a negative electrode tab (3212). On a plane perpendicular to the first direction (X), the orthographic projection of the positive electrode body (3111) is located within the orthographic projection of the negative electrode body (3211). The positive electrode sheet (310) further includes an insulating layer (313) and a positive electrode active material layer (312). The positive electrode body (3111) includes a first surface (3112). The first surface (3112) includes a first inner peripheral region (3113) and a first outer peripheral region (3114). The first outer peripheral region (3114) surrounds the first inner peripheral region (3113) and is located outside the first inner peripheral region (3113). The first inner peripheral region (3113) is provided with the positive electrode active material layer (312). At least a portion of the first outer peripheral region (3114) is provided with the insulating layer (313).

2. The single-cell battery according to claim 1, characterized in that, The positive electrode (310) also has a second direction (Y) perpendicular to the first direction (X), and the first peripheral region (3114) includes a first edge region (3115) and a second edge region (3116) spaced apart along the second direction (Y), the insulating layer (313) is disposed in the first edge region (3115), and / or the insulating layer (313) is disposed in the second edge region (3116).

3. The single-cell battery according to claim 1, characterized in that, The electrode assembly (300) is a wound structure. The positive electrode (310) also has a second direction (Y) perpendicular to the first direction (X). The second direction (Y) is the width direction of the positive electrode (310). The first peripheral region (3114) includes a first edge region (3115) and a second edge region (3116) spaced apart along the second direction (Y). Along the second direction (Y), one side of the negative electrode body (3211) is flush with the side of the first edge region (3115) away from the second edge region (3116), and the other side protrudes from the second edge region (3116). The insulating layer (313) is disposed in the second edge region (3116). The positive electrode tab (314) is connected to the side of the second edge region (3116) away from the positive electrode active material layer (312) along the second direction (Y).

4. The single-cell battery according to claim 1, characterized in that, The positive electrode body (3111) further includes a second surface (3117), which is disposed opposite to the first surface (3112) along the first direction (X). The second surface (3117) includes a second inner peripheral region (3118) and a second outer peripheral region (3119), which surrounds the second inner peripheral region (3118) and is located outside the second inner peripheral region (3118). The second inner peripheral region (3118) is provided with the positive electrode active material layer (312), and at least a portion of the second outer peripheral region (3119) is provided with the insulating layer (313), and the insulating layer (313) includes an inner side close to the positive electrode active material layer (312), and the inner side of the insulating layer (313) is connected to the positive electrode active material layer (312).

5. The single-cell battery according to claim 4, characterized in that, The insulating layer (313) at least partially overlaps with the positive electrode active material layer (312) in the first direction (X).

6. The single-cell battery according to claim 1, characterized in that, Along the first direction (X), the absolute value of the difference between the size of the positive electrode active material layer (312) and the size of the insulating layer (313) is 15um to 90um.

7. The single-cell battery according to any one of claims 1 to 6, characterized in that, The insulating layer (313) comprises inorganic particles and a binder.

8. The single-cell battery according to claim 7, characterized in that, The inorganic particles include at least one of boehmite and alumina.

9. The single-cell battery according to claim 1, characterized in that, The positive electrode sheet (310) has a second direction (Y) perpendicular to the first direction (X). The first peripheral region (3114) includes a second edge region (3116). The insulating layer (313) is disposed in the second edge region (3116). The positive electrode tab (314) is connected to the side of the second edge region (3116) away from the positive electrode active material layer (312) along the second direction (Y). The extension dimension of the insulating layer (313) along the second direction (Y) is W1. The extension dimension of the positive electrode body (3111) along the second direction (Y) is W2, satisfying that the ratio of W1 to W2 is in the range of 1% to 10%.

10. The single-cell battery according to claim 9, characterized in that, The encapsulation structure (100) includes a housing (110) and a top cover assembly (120). The top cover assembly (120) includes a top cover body (121), which is connected to the housing (110) and together with the housing (110) forms the receiving cavity (111). The positive electrode post (210) and the negative electrode post (220) are spaced apart on the top cover body (121). Along the first direction (X), the top cover body (121) has a third surface (1211) facing away from the electrode assembly (300). The positive electrode plate (310) also has a third direction (Z) perpendicular to the first direction (X). The component (300) includes an electrode body (315) and a positive electrode tab (314) and / or a negative electrode tab (3212) connected to the electrode body (315) and close to the top cover body (121). The positive electrode tab (314) is in contact with and connected to the positive electrode post (210), and the negative electrode tab (3212) is in contact with and connected to the negative electrode post (220). The positive electrode body (3111), the diaphragm (330) and the negative electrode body (3211) are stacked along the first direction (X) and wound along the third direction (Z) to form the electrode body (315). The electrode body (315) has a fourth surface (3151) close to the top cover assembly (120). The positive electrode (310) also has a second direction (Y) perpendicular to the first direction (X). Along the second direction (Y), the distance between the third surface (1211) and the fourth surface (3151) is D1, satisfying: .

11. The single-cell battery according to claim 1, characterized in that, The diaphragm (330) includes a base film (331) and an adhesive layer (332). Along the first direction (X), at least one side of the base film (331) is provided with the adhesive layer (332), and the adhesive layer (332) is bonded to at least one of the positive electrode (310) and the negative electrode (320).

12. The single-cell battery according to claim 1, characterized in that, The single cell also includes a positive electrode post (210) and a negative electrode post (220). The positive terminal (210) is connected to and passes through the encapsulation structure (100), and the positive terminal tab (314) is in contact with and connected to the positive terminal (210); And / or, the negative terminal (220) is connected to and passes through the encapsulation structure (100), and the negative terminal tab (3212) is in contact with and connected to the negative terminal (220).

13. The single-cell battery according to claim 12, characterized in that, The positive electrode tab (314) includes a positive electrode connection portion (3141), which is welded to the positive electrode post (210) to form a positive electrode solder area. The electrode assembly (300) also includes a first protective layer (410), which is connected to the side of the positive electrode connection portion (3141) away from the positive electrode post (210) and covers the positive electrode solder area. And / or, the negative electrode tab (3212) includes a negative electrode connection portion (3213), which is welded to the negative electrode post (220) to form a negative electrode solder area, and the electrode assembly (300) further includes a second protective layer (420), which is connected to the side of the negative electrode connection portion (3213) away from the negative electrode post (220) and covers the negative electrode solder area.

14. The single-cell battery according to claim 13, characterized in that, The positive electrode post (210) includes a first connection surface (211) near the electrode assembly (300), the area of ​​the first connection surface (211) is S1, and the area of ​​the positive electrode solder area is S2, satisfying that: the ratio of S2 to S1 is in the range of 2% to 50%; And / or, the negative electrode post (220) includes a second connection surface (221) near the electrode assembly (300), the area of ​​the second connection surface (221) is S3, and the area of ​​the negative electrode solder area is S4, satisfying that the ratio of S4 to S3 is in the range of 2% to 50%.

15. The single-cell battery according to claim 12, characterized in that, The positive electrode post (210) includes a first connecting surface (211) near the electrode assembly (300), the first connecting surface (211) extends along a first direction (X), the positive electrode tab (314) is bent and includes a positive electrode connection portion (3141) at one end away from the positive electrode body (3111), the positive electrode connection portion (3141) extends along the first direction (X), and the positive electrode connection portion (3141) is connected to the first connecting surface (211). And / or, the negative electrode post (220) includes a second connecting surface (221) near the electrode assembly (300), the second connecting surface (221) extending along a first direction (X), the negative electrode tab (3212) is bent and includes a negative electrode connection portion (3213) at one end away from the negative electrode body (3211), the negative electrode connection portion (3213) extending along the first direction (X), and the negative electrode connection portion (3213) being connected to the second connecting surface (221).

16. The single-cell battery according to claim 15, characterized in that, The electrode assembly (300) further includes a third protective layer (430). The positive electrode tab (314) includes a connected positive electrode tab body (3142) and a positive electrode connection portion (3141). The positive electrode tab body (3142) is connected to the positive electrode body (3111). The positive electrode connection portion (3141) is in contact with and connected to the positive electrode post (210). At least a portion of the surface of the positive electrode tab body (3142) is covered with the third protective layer (430). And / or, the electrode assembly (300) further includes a fourth protective layer (440), the negative electrode tab (3212) includes a connected negative electrode tab body (3214) and a negative electrode connection portion (3213), the negative electrode tab body (3214) is connected to the negative electrode body (3211), the negative electrode connection portion (3213) is in contact with and connected to the negative electrode post (220), and at least a portion of the surface of the negative electrode tab body (3214) is covered with the fourth protective layer (440).

17. A battery pack, characterized in that, It includes any one of the single-cell batteries according to claims 1 to 16.

18. An electrical appliance, characterized in that, Includes the battery pack as described in claim 17.

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