Battery cell, battery and electric device

Abstract

The embodiment of the invention provides a battery cell, a battery and a power utilization device, and relates to the technical field of batteries. An isolating membrane of the battery cell is arranged between a first pole piece and a second pole piece, the first pole piece is bent to form a corner part, an insulation blocking part is arranged on an active substance layer located on the corner part and comprises a first insulation blocking layer and a second insulation blocking layer, and the first insulation blocking layer and the second insulation blocking layer are arranged in the winding direction of the battery cell. At least one end of the first insulation barrier layer and at least one end of the second insulation barrier layer are arranged in a staggered mode to form a staggered area, the size of the staggered area is A1, the minimum size of the size of the first insulation barrier layer and the size of the second insulation barrier layer is A2, and the ratio of A1 to A2 is a, the ratio of the total number of layers of the first insulating barrier layers and the second insulating barrier layers to the total number of layers of the first pole piece is m, and the mass ratio of the copper element of the first current collector to the first current collector is b. And a / (m * b) is greater than or equal to 0.59 and less than or equal to 1752.18, so that lithium precipitation is not easy to occur, and the thermal runaway risk is relatively low in the use process of the battery.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a battery cell, a battery, and an electrical device. Background Technology

[0002] Lithium-ion batteries have advantages such as high energy density, good cycle performance, no memory effect, safety, and environmental friendliness, and are widely used in electric vehicles and portable electronic products. The cell of a lithium-ion battery is formed by winding electrodes and a separator.

[0003] In related technologies, the stress is concentrated in the bending area of ​​lithium-ion battery cells. In addition, since the cells need to be pressed after winding, an insulating barrier layer is set in the bending area of ​​the cells to reduce the shedding of the active material layer.

[0004] However, the installation of an insulating barrier layer affects the extraction and insertion of lithium ions, leading to a significant risk of thermal runaway in the battery. Summary of the Invention

[0005] This application provides a battery cell, a battery, and an electrical device to solve the problem that the installation of an insulating barrier layer affects the extraction and insertion of lithium ions, leading to a greater risk of thermal runaway in the battery.

[0006] In a first aspect, embodiments of this application provide a battery cell, including a first electrode, a second electrode, a separator, and an insulating barrier portion;

[0007] The separator is disposed between the first electrode and the second electrode, and the first electrode, the separator, and the second electrode are wound together.

[0008] The first electrode is bent to form a corner portion, and the first electrode includes a first current collector and active material layers disposed on both sides of the first current collector;

[0009] The insulating barrier portion is disposed on the active material layer at the corner. The insulating barrier portion includes a first insulating barrier layer and a second insulating barrier layer. In the thickness direction of the first electrode, the first insulating barrier layer and the second insulating barrier layer are bonded to both sides of the first electrode. Along the winding direction of the battery cell, the first insulating barrier layer and the second insulating barrier layer are offset at least one end to form an offset region. The size of the offset region is A1. The smaller size of the first insulating barrier layer and the second insulating barrier layer is A2. The ratio of A1 to A2 is a. The units of A1 and A2 are both mm.

[0010] The ratio of the total number of the first insulating barrier layer and the second insulating barrier layer to the total number of the first electrode sheet is m;

[0011] The first current collector includes copper and aluminum, wherein the copper content of the first current collector is b% by mass.

[0012] The following conditions must be met: 0.59 ≤ a / (m×b) ≤ 1752.18.

[0013] Secondly, embodiments of this application provide a battery, including a casing and a battery cell as described in the first aspect, wherein the casing is provided with terminals, and the battery cell is disposed inside the casing and electrically connected to the terminals.

[0014] Thirdly, embodiments of this application provide an electrical device including the battery of the second aspect.

[0015] By controlling a / (m×b) to be greater than or equal to 0.59 and less than or equal to 1752.18, the active material of the electrode corresponding to the corner of the cell is less likely to fall off, thereby improving the cycle life of the battery. It can also reduce the obstruction of lithium ions by the insulating barrier and prevent lithium plating from occurring on the surface of the negative electrode corresponding to the corner, thus reducing the risk of thermal runaway during battery use. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This application provides a schematic diagram of the structure of a battery cell.

[0018] Figure 2 for Figure 1 A top view of the battery cell;

[0019] Figure 3 A cross-sectional schematic diagram of the first electrode and the insulating barrier portion is provided for the embodiments of this application;

[0020] Figure 4 A cross-sectional schematic diagram of the unfolded first electrode and insulating barrier portion is provided for the embodiments of this application;

[0021] Figure 5 A cross-sectional schematic diagram of the unfolded first electrode and insulating barrier portion is provided for the embodiments of this application;

[0022] Figure 6 This application provides a cross-sectional schematic diagram of an insulating barrier portion according to an embodiment of the present application;

[0023] Figure 7A fourth cross-sectional schematic diagram of the first electrode and the insulating barrier portion is provided for embodiments of this application;

[0024] Figure 8 A fifth type of cross-sectional schematic diagram of the first electrode and the insulating barrier portion is provided for embodiments of this application;

[0025] Figure 9 This is a schematic diagram of the structure of a battery provided in an embodiment of this application.

[0026] Explanation of reference numerals in the attached figures:

[0027] 1-Cell; 100-Straight area; 110-Bending area; 10-First electrode; 103-Corner; 101-First current collector; 102-Active material layer; 20-Second electrode; 40a-Base film layer; 40b-Adhesive layer; 30-Separator; 40-Insulating barrier; 3-Electrical post; 2-Shell; 401-First insulating barrier layer; 402-Second insulating barrier layer; 403-Offset area; 4031-First region; 4032-Second region; 4033-Third region; 4034-Fourth region; 4035-Through hole; 4036-Blank area; 1010-Head end. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0029] It should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0030] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "fixation," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between components; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0031] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0032] In the above description, the terms "one embodiment," "some embodiments," "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. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0033] The following detailed description of the battery cell, battery, and power device provided in the embodiments of this application is based on specific examples.

[0034] Firstly, see [the following] Figure 1 and Figure 2 This application provides a battery cell 1, which includes a first electrode 10, a second electrode 20, a separator 30, and an insulating barrier 40.

[0035] The length direction of cell 1 is the X direction. The thickness direction of cell 1 is the Y direction. The height direction of cell 1 is the Z direction. The X, Y, and Z directions are perpendicular to each other.

[0036] Cell 1 is the component in the battery where electrochemical reactions occur; it is the smallest unit in the battery capable of carrying out electrochemical reactions such as charging or discharging.

[0037] Cell 1 is the basic unit in a battery. For example, cell 1 is a lithium-ion cell. Lithium-ion cells operate by the intercalation and deintercalation of lithium ions between the positive and negative electrode plates.

[0038] The battery cell 1 is roughly rectangular in shape. Along the length of the battery cell 1, the battery cell 1 includes a straight section 100 and two bending sections 110, which are located on both sides of the straight section 100.

[0039] The separator 30 is disposed between the first electrode 10 and the second electrode 20, and the first electrode 10, the separator 30, and the second electrode 20 are wound together. The winding direction of the first electrode 10 and the second electrode 20 is the same as the winding direction of the battery cell 1.

[0040] See Figure 3 The first electrode 10 can be either a positive electrode or a negative electrode. When the first electrode 10 is a positive electrode, the second electrode 20 is a negative electrode. When the first electrode 10 is a negative electrode, the second electrode 20 is a positive electrode. In this embodiment, the first electrode 10 is a positive electrode and the second electrode 20 is a negative electrode.

[0041] The separator 30 is disposed between the positive electrode and the negative electrode to separate the positive electrode and the negative electrode and prevent the positive electrode and the negative electrode from short-circuiting due to contact.

[0042] The separator 30 can be made of at least one of glass fiber, nonwoven fabric, polyethylene (PE), polypropylene (PP), and polyvinylidene fluoride. A coating can also be applied to the surface of the separator 30, which can be an inorganic coating and / or an organic coating. The inorganic coating material includes at least one of alumina, silicon dioxide, titanium dioxide, magnesium oxide, zirconium oxide, and boehmite. The organic coating includes at least one of aramid coating and polyvinylidene fluoride (PVDF) coating.

[0043] The positive electrode is one of the core components in a battery that carries the positive electrode active material. During charging, metal ions (e.g., lithium ions) are released from the lattice of the positive electrode active material (oxidation reaction), migrate through the electrolyte, and intercalate into the negative electrode. During discharging, metal ions (e.g., lithium ions) are released from the negative electrode and intercalate into the lattice of the positive electrode active material (reduction reaction), thus realizing the storage and release of lithium ions.

[0044] The current collector of the positive electrode is a positive electrode current collector, and the active material layer 102 of the positive electrode is a positive electrode active material layer. The positive electrode active material layer is coated on at least one surface of the positive electrode current collector, and the positive electrode active material layer includes a positive electrode active material, a conductive agent, and a binder.

[0045] The positive electrode active material includes, but is not limited to, at least one of the following materials: lithium phosphate, lithium transition metal oxide and their respective modified compounds, or other materials that can be used as positive electrode active materials for batteries. These positive electrode active materials can be used alone or in combination of two or more.

[0046] Lithium-containing phosphates include, but are not limited to, at least one of lithium iron phosphate (e.g., LiFePO4, also referred to as LFP), lithium iron phosphate and carbon composites, lithium manganese phosphate (e.g., LiMnPO4), lithium manganese phosphate and carbon composites, lithium manganese iron phosphate, and lithium manganese iron phosphate and carbon composites. Lithium transition metal oxides include, but are not limited to, at least one of lithium cobalt oxides (e.g., LiCoO2), lithium nickel oxides (e.g., LiNiO2), lithium manganese oxides (e.g., LiMnO2 or LiMn2O4), lithium nickel cobalt oxides, lithium manganese cobalt oxides, lithium nickel manganese oxides, lithium nickel cobalt manganese oxides, lithium nickel cobalt aluminum oxides, and their modified compounds.

[0047] The conductive agent of the positive electrode includes, but is not limited to, one or more combinations of graphite, superconducting carbon, carbon black (such as acetylene black, Ketjen black or Super P), carbon nanotubes, graphene and carbon nanofibers.

[0048] The binder for the positive electrode includes, but is not limited to, one or more combinations of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), PVDF-tetrafluoroethylene-propylene terpolymer, PVDF-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, fluorinated acrylate resin, styrene-butadiene rubber, polyacrylic acid, sodium polyacrylate, polyacrylamide, polyvinyl alcohol, sodium alginate, polymethacrylic acid, carboxymethyl chitosan, etc.

[0049] The positive electrode current collector is a conductive metal foil, which can be made of stainless steel, copper, aluminum, aluminum alloy, nickel, carbon electrode, or titanium with a silver-plated surface. Composite current collectors can also be used, which may include a polymer material base layer and a metal layer. Composite current collectors are formed by forming metal materials (aluminum, aluminum alloy, copper, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0050] During battery charging, active ions (such as Li) from the positive electrode are embedded in the negative electrode, while electrons from the positive electrode are transferred to the negative electrode through an external circuit, maintaining charge balance. During discharging, the active ions (such as Li) previously embedded in the negative electrode are released, while electrons from the negative electrode are transferred to the positive electrode through an external circuit, maintaining charge balance and achieving energy storage and release.

[0051] The current collector of the negative electrode is a negative electrode current collector, and the active material layer 102 of the negative electrode is a negative electrode active material layer. The negative electrode active material layer is disposed on at least one surface of the negative electrode current collector.

[0052] The negative electrode current collector is a conductive metal foil, which can be made of stainless steel, copper, aluminum, aluminum alloy, nickel, carbon electrode, or titanium with a silver-plated surface. Composite current collectors can also be used, which may include a polymer material base layer and a metal layer. Composite current collectors are formed by forming a metal material (aluminum, aluminum alloy, copper, nickel, nickel alloy, titanium, titanium alloy, silver or silver alloy, etc.) on a polymer material substrate (such as a polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, or polyethylene substrate).

[0053] The negative electrode active material layer includes the negative electrode active material, conductive agent, binder, etc. The negative electrode active material can be a carbon-based material such as graphite, porous carbon, hard carbon, soft carbon, or mesophase carbon microspheres, or a silicon-based material such as elemental silicon, silicon oxide, silicon-carbon composite, or silicon-nitrogen composite.

[0054] The conductive agent in the negative electrode active material layer can be conductive carbon black or carbon nanotubes, and the binder can be styrene-butadiene rubber or polyacrylic acid, etc.

[0055] The first electrode 10 is wound up. The first electrode 10 is bent to form a corner portion 103, that is, the first electrode 10 forms a corner portion 103 in the bending area 110. There are multiple corner portions 103.

[0056] See Figure 3 The first electrode 10 includes a first current collector 101 and active material layers 102 disposed on both sides of the first current collector 101. It should be noted that when the first electrode 10 is a positive electrode, the first current collector 101 is a positive current collector.

[0057] Insulating barrier 40 (see) Figure 2 The active material layer 102 is disposed on the corner portion 103. The insulating barrier portion 40 is used to relieve bending stress and suppress electrode shedding. For example, the insulating barrier portion 40 can be tape. It should be noted that the detachment of the active material layer 102 on the cell 1 represents electrode shedding.

[0058] The insulating barrier portion 40 includes a base film layer 40a and an adhesive layer 40b (see [link]). Figure 6 Adhesive layer 40b is coated on base film layer 40a, and base film layer 40a is used to support adhesive layer 40b.

[0059] The base film layer 40a can be made of at least one of the following: polyvinyl chloride, polyethylene, polypropylene, polyvinylidene fluoride, hexafluoropropylene-vinylidene fluoride copolymer, tetrafluoropropylene-vinylidene fluoride copolymer, trifluorochloropropylene-vinylidene fluoride copolymer, polyethylene terephthalate, polyimide, polyetherimide, polycarbonate, polystyrene, polyphenylene sulfide, polyvinylidene fluoride, polyvinylidene fluoride copolymer, polyarylate, fiber, nylon, and nonwoven fabric.

[0060] The base film layer 40a is bonded to the active material layer 102 via the adhesive layer 40b. The adhesive layer 40b can be made of at least one of the following: acrylic acid-acrylate copolymer, butadiene-styrene copolymer, styrene-acrylic acid copolymer, styrene-acrylate copolymer, ethylene-vinyl acetate copolymer, acrylic acid-grafted polyethylene, maleic anhydride-grafted polyethylene, acrylic acid-grafted polypropylene, polyvinylidene fluoride, maleic anhydride-grafted polypropylene, carboxymethyl cellulose, polyimide, polyetherimide, styrene-isoprene-styrene copolymer rubber, polyethylene phthalate, ethylene-vinyl acetate copolymer bisphenol A type epoxy resin, ethylene-vinyl acetate copolymer bisphenol F type epoxy resin, glycerol ether type epoxy resin, glycerol ester type epoxy resin, silicone type resin, polyurethane, and styrene-isoprene-styrene copolymer.

[0061] In some examples, the insulating barrier portion 40 includes a first insulating barrier layer 401 and a second insulating barrier layer 402 (see [reference]). Figure 3 In the thickness direction of the first electrode 10, the first insulating barrier layer 401 and the second insulating barrier layer 402 are bonded to both sides of the first electrode 10. Specifically, in the thickness direction of the first electrode 10, the first insulating barrier layer 401 and the second insulating barrier layer 402 are respectively bonded to the surface of the active material layer 102 of the first electrode 10. This arrangement allows the first insulating barrier layer 401 and the second insulating barrier layer 402 to be fixed to the active material layer 102 of the first electrode 10.

[0062] The number of first insulating barrier layers 401 can be one or more.

[0063] The first insulating barrier layer 401 can be disposed on one surface of the corresponding active material layer 102 of one corner portion 103 of the battery cell 1, or it can be disposed on one surface of the corresponding active material layer 102 of all corner portions 103 of the battery cell 1.

[0064] The number of second insulating barrier layers 402 can be one or more.

[0065] The second insulating barrier layer 402 can be disposed on one surface of the corresponding active material layer 102 of one corner portion 103 of the battery cell 1, or it can be disposed on one surface of the corresponding active material layer 102 of all corner portions 103 of the battery cell 1.

[0066] See Figure 3 Along the winding direction of the battery cell 1, the first insulating barrier layer 401 and the second insulating barrier layer 402 are offset at least at one end to form an offset region 403.

[0067] Along the winding direction of cell 1, the size of the offset region 403 is A1.

[0068] When the first insulating barrier layer 401 and the second insulating barrier layer 402 are offset at one end along the winding direction of the battery cell 1, the offset dimension of one end of the first insulating barrier layer 401 and the second insulating barrier layer 402 is A1. When the two ends of the first insulating barrier layer 401 and the second insulating barrier layer 402 are offset at both ends along the winding direction of the battery cell 1, the sum of the offset dimensions of the two ends of the first insulating barrier layer 401 and the second insulating barrier layer 402 is A1.

[0069] Along the winding direction of cell 1, the smallest dimension among the dimensions of the first insulating barrier layer 401 and the second insulating barrier layer 402 is A2. The ratio of A1 to A2 is a, and the units of A1 and A2 are both mm.

[0070] The ratio of the total number of layers of the first insulating barrier layer 401 and the second insulating barrier layer 402 to the total number of layers of the first electrode 10 is m.

[0071] The total number of the first insulating barrier layer 401 and the second insulating barrier layer 402 is the sum of the number of the first insulating barrier layer 401 and the number of the second insulating barrier layer 402 on a bending region 110 of the battery cell 1.

[0072] The total number of layers of the first electrode 10 is the total number of layers of the first electrode 10 bent in a bending region 110 of the cell 1.

[0073] The first current collector 101 includes copper and aluminum elements, with copper accounting for b% of the mass of the first current collector 101, that is, the content of copper element is b%.

[0074] a, m, and b satisfy: 0.59 ≤ a / (m×b) ≤ 1752.18. The value of a / (m×b) can be 0.59, 0.6, 20, 100, 1000, 1500, 1600, or 1752.18, etc.

[0075] It should be noted that when both sides of the first current collector 101 in the first electrode 10 (both sides of the first current collector 101 in the thickness direction of the first electrode 10) are coated with active material layers 102, a first insulating barrier layer 401 and a second insulating barrier layer 402 need to be set on the active material layers 102 on both sides of the corner portion 103. This can effectively reduce the risk of material shedding. However, setting the first insulating barrier layer 401 and the second insulating barrier layer 402 on both sides will hinder lithium-ion transport, leading to lithium plating and affecting battery safety. Therefore, the first insulating barrier layer 401 and the second insulating barrier layer 402 on both sides can be staggered to reduce the overlap area and improve lithium-ion transport. However, this design will exacerbate the risk of material shedding. Therefore, it is necessary to control the ratio of the total number of the first insulating barrier layer 401 and the second insulating barrier layer 402 to the total number of layers of the first electrode 10 to reduce material shedding. However, the ratio of the total number of layers of the first insulating barrier layer 401 and the second insulating barrier layer 402 to the total number of layers of the first electrode 10 cannot be excessively adjusted. Therefore, it is necessary to increase the content of copper doping in the first current collector 101 of the first electrode 10 to improve the flexibility of the first current collector 101 in the first electrode 10 and prevent the risk of material falling off due to poor flexibility when it is bent.

[0076] If a / (m×b) is greater than 1752.18, at least one of the following situations will occur: a proportion is too large, m proportion is too small, and b proportion is too small. This will cause cell 1 to easily lose material, resulting in a reduction in battery cycle life.

[0077] It should be noted that if a / (m×b) is greater than 1752.18, the proportion of a will be too large, resulting in a small overlap area between the first insulating barrier layer 401 and the second insulating barrier layer 402. This will make the first insulating barrier layer 401 and the second insulating barrier layer 402 poor in protecting the active material layer 102, causing the cell 1 to easily lose material and reducing the battery cycle life.

[0078] If a / (m×b) is greater than 1752.18, the proportion of m will be too small, resulting in too few layers of the first insulating barrier layer 401 and the second insulating barrier layer 402. This leads to poor protection of the active material layer 102 by the first insulating barrier layer 401 and the second insulating barrier layer 402, making the cell 1 prone to material loss and reducing the battery cycle life.

[0079] If a / (m×b) is greater than 1752.18, the proportion of b will be too small, resulting in a small mass ratio of copper in the first current collector 101. This will make the first current collector 101 less flexible, causing the cell 1 to easily lose material and reducing the battery cycle life.

[0080] If a / (m×b) is less than 0.59, at least one of the following situations will occur: a proportion is too small and m proportion is too large. This makes lithium-ion transport difficult, lithium plating is likely to occur, and short circuits between the electrodes of the cell are likely to occur. This makes the risk of thermal runaway greater during battery use.

[0081] It should be noted that if a / (m×b) is greater than 1752.18, the proportion of a will be too small, resulting in a large overlap area between the first insulating barrier layer 401 and the second insulating barrier layer 402. This makes lithium-ion transport difficult, easily leads to lithium plating, and causes short circuits between the electrodes of the cell, resulting in a greater risk of thermal runaway during battery use.

[0082] If a / (m×b) is greater than 1752.18, the proportion of m will be too large, resulting in an excessive number of layers in the first insulating barrier layer 401 and the second insulating barrier layer 402. This will significantly hinder lithium-ion transport, making lithium plating more likely. Consequently, short circuits between the electrodes of the battery cell are more likely, leading to a greater risk of thermal runaway during battery use.

[0083] By ensuring that a / (m×b) is greater than or equal to 0.59 and less than or equal to 1752.18, the battery cell is less prone to material loss, the battery cycle life is improved, and lithium plating is less likely to occur, thus reducing the risk of thermal runaway during battery use.

[0084] In some examples, a, m, and b satisfy: 2.89 ≤ a / (m×b) ≤ 311.43. The value of a / (m×b) can be 2.89, 2.9, 3, 20, 100, 200, 300, 310, or 311.43, etc. Compared to a / (m×b) being greater than 311.43 and less than or equal to 1752.18, this makes the cell less prone to material loss, thus improving battery cycle life. Compared to a / (m×b) being greater than or equal to 0.59 and less than 2.89, this makes lithium plating less likely, reducing the risk of thermal runaway during battery use. Therefore, by ensuring a / (m×b) is greater than or equal to 2.89 and less than or equal to 311.43, it is possible to further reduce the likelihood of material loss from the cell, improve battery cycle life, and further reduce the risk of lithium plating, thus minimizing the risk of thermal runaway during battery use.

[0085] In one possible implementation, the starting end of the first electrode 10 winding is the first end 1010 of the first electrode 10, and an insulating barrier portion 40 is provided within the first 5 turns of the first electrode 10 closest to the first end 1010 in the cell 1. With this arrangement, since the inner ring of the first electrode 10 near the first end 1010 has stress concentration and a large radius of curvature, the risk of material loss is serious. Therefore, the insulating barrier portion 40 is provided within the first 5 turns closest to the first end 1010 to protect the active material layer 102 of the first electrode 10 and reduce the risk of material loss.

[0086] The first electrode 10 has an initial end and a tail end along the winding direction of the cell 1. The initial end and the tail end are located in the straight region 100. The first electrode 10 passes through two bending regions 110 of the cell 1. The initial end and the tail end overlap in the thickness direction of the cell 1.

[0087] For example, the first end 1010 of the first electrode 10 can be used as the initial end of the first electrode 10 in the cell 1 that is closest to the first end 1010 of the first electrode 10. The first end 1010 of the first electrode 10 is wound 5 times as the 5 turns of the first electrode 10 that are closest to the first end 1010 of the first electrode 10 in the cell 1.

[0088] In one possible implementation, a first insulating barrier layer 401 is disposed on the inner side of the first electrode 10, and a second insulating barrier layer 402 is disposed on the outer side of the first electrode 10.

[0089] The battery cell 1 has a winding hole. The side of each turn of the first electrode 10 facing the winding hole is the inner side of the first electrode 10; the side of each turn of the first electrode 10 facing the outside of the battery cell 1 is the outer side of the first electrode 10, that is, the side of each turn of the first electrode 10 away from the winding hole is the first electrode 10.

[0090] A1 satisfies: 1mm ≤ A1 ≤ 15mm. The value of A1 can be 1mm, 2mm, 4mm, 5mm, 8mm, 10mm, 12mm or 15mm, etc.

[0091] If A1 is greater than 15mm, the size of the offset region 403 along the winding direction of cell 1 will be too large, resulting in a small overlap area between the first insulating barrier layer 401 and the second insulating barrier layer 402. This leads to poor protection of the active material layer 102 by the first and second insulating barrier layers 401 and 402, making cell 1 prone to material loss. If A1 is less than 1mm, the size of the offset region 403 along the winding direction of cell 1 will be too small, resulting in a large overlap area between the first insulating barrier layer 401 and the second insulating barrier layer 402. This makes lithium-ion transport difficult and prone to lithium plating. By ensuring A1 is greater than or equal to 1mm and less than or equal to 15mm, cell 1 is less prone to material loss and lithium plating.

[0092] In some examples, 1mm ≤ A1 ≤ 4mm. Compared to A1 being greater than 4mm and less than or equal to 15mm, using A1 greater than or less than or equal to 1mm and less than or equal to 4mm can further reduce the material loss of cell 1 while reducing the risk of lithium plating.

[0093] A2 satisfies: 10mm ≤ A2 ≤ 30mm. The value of A2 can be 10mm, 11mm, 15mm, 20mm, 21mm, 25mm or 30mm, etc.

[0094] If A2 is greater than 30mm, the smallest dimension of the first insulating barrier layer 401 and the second insulating barrier layer 402 along the winding direction of cell 1 will be too large, making lithium-ion transport difficult and prone to lithium plating. If A2 is less than 10mm, the smallest dimension of the first insulating barrier layer 401 and the second insulating barrier layer 402 along the winding direction of cell 1 will be too small, resulting in poor protection of the active material layer 102 by the smallest insulating barrier layer along the winding direction of cell 1, making cell 1 prone to material loss. By having A2 greater than or equal to 10mm and less than or equal to 30mm, cell 1 is less prone to material loss and lithium plating.

[0095] The condition 'a' satisfies: 0.033 ≤ a ≤ 0.6. The values ​​of 'a' can be 0.033, 0.04, 0.1, 0.2, 0.3, 0.4, 0.5, or 0.6, etc. In some examples, 0.05 ≤ a ≤ 0.55.

[0096] If a is greater than 0.6, the overlap area of ​​the first insulating barrier layer 401 and the second insulating barrier layer 402 will be small, resulting in poor protection of the active material layer 102 by the first and second insulating barrier layers 401 and 402, making the cell 1 prone to material shedding. If a is less than 0.033, the overlap area of ​​the first insulating barrier layer 401 and the second insulating barrier layer 402 will be large, making lithium-ion transport difficult and prone to lithium plating. By ensuring that a is greater than or equal to 0.033 and less than or equal to 0.6, the cell 1 can be made less prone to material shedding and lithium plating.

[0097] It should be noted that, in this embodiment, the battery cell 1 can satisfy one of the following conditions: A1 is greater than or equal to 1 mm and less than or equal to 15 mm, A2 is greater than or equal to 10 mm and less than or equal to 30 mm, and a is greater than or equal to 0.033 and less than or equal to 0.6.

[0098] See in some examples Figure 3 Along the winding direction of the battery cell, at least one end of the second insulating barrier layer 402 extends beyond the end of the first insulating barrier layer 401, and A1 satisfies: 1mm≤A1≤12mm. The value of A1 can be 1mm, 2mm, 5mm, 8mm, 10mm, 11mm or 12mm, etc.

[0099] If A1 is greater than 12mm, the first insulating barrier layer 401 will be located inside the first electrode 10, and the second insulating barrier layer 402 will be located outside the first electrode 10. When at least one end of the second insulating barrier layer exceeds the end of the first insulating barrier layer along the winding direction of the battery cell, the size of the offset area 403 along the winding direction of the battery cell 1 will be too large, resulting in a small overlap area between the first insulating barrier layer 401 and the second insulating barrier layer 402. This will lead to poor protection of the active material layer 102 by the first insulating barrier layer 401 and the second insulating barrier layer 402, and the battery cell 1 will easily lose material. If A1 is less than 1 mm, the first insulating barrier layer 401 will be located inside the first electrode 10, and the second insulating barrier layer 402 will be located outside the first electrode 10. Furthermore, along the winding direction of the battery cell, at least one end of the second insulating barrier layer will extend beyond the end of the first insulating barrier layer. Consequently, the size of the offset region 403 along the winding direction of the battery cell 1 will be too small, resulting in a large overlap between the first insulating barrier layer 401 and the second insulating barrier layer 402. This makes lithium-ion transport difficult and prone to lithium plating. By ensuring A1 is greater than or equal to 1 mm and less than or equal to 12 mm, with the first insulating barrier layer 401 located inside the first electrode 10 and the second insulating barrier layer 402 located outside the first electrode 10, and along the winding direction of the battery cell, at least one end of the second insulating barrier layer extends beyond the end of the first insulating barrier layer. This makes it less likely for the battery cell 1 to lose material and also less likely for lithium plating to occur.

[0100] See in some examples Figure 4 Along the winding direction of the battery cell 1, at least one end of the first insulating barrier layer 401 extends beyond the end of the second insulating barrier layer 402, and A1 satisfies: 2mm≤A1≤15mm. The value of A1 can be 2mm, 3mm, 5mm, 8mm, 10mm, 12mm or 15mm, etc.

[0101] If A1 is greater than 15mm, the first insulating barrier layer 401 will be located inside the first electrode 10, and the second insulating barrier layer 402 will be located outside the first electrode 10. Along the winding direction of the cell 1, if at least one end of the first insulating barrier layer 401 exceeds the end of the second insulating barrier layer 402, the size of the offset area 403 along the winding direction of the cell 1 will be too large, resulting in a small overlap area between the first insulating barrier layer 401 and the second insulating barrier layer 402. This will lead to poor protection of the active material layer 102 by the first insulating barrier layer 401 and the second insulating barrier layer 402, and the cell 1 will easily lose material. If A1 is less than 2 mm, the first insulating barrier layer 401 will be located inside the first electrode 10, and the second insulating barrier layer 402 will be located outside the first electrode 10. Along the winding direction of the cell 1, if at least one end of the first insulating barrier layer 401 extends beyond the end of the second insulating barrier layer 402, the size of the offset region 403 along the winding direction of the cell 1 will be too small. This results in a large overlap area between the first and second insulating barrier layers 401 and 402, making lithium-ion transport difficult and prone to lithium plating. By ensuring A1 is greater than or equal to 2 mm and less than or equal to 15 mm, with the first insulating barrier layer 401 located inside the first electrode 10 and the second insulating barrier layer 402 located outside the first electrode 10, and along the winding direction of the cell 1, if at least one end of the first insulating barrier layer 401 extends beyond the end of the second insulating barrier layer 402, the cell 1 is less prone to material loss and lithium plating.

[0102] For example, see Figure 4 Along the winding direction of the cell 1, the two opposite ends of the first insulating barrier layer 401 extend beyond the two opposite ends of the second insulating barrier layer 402. Compared to the situation where only one end of the first insulating barrier layer 401 extends beyond one end of the second insulating barrier layer 402 along the winding direction of the cell 1, this further reduces material loss on the inner side of the first electrode 10. In this example, the sum of the offset dimensions of the two ends of the first insulating barrier layer 401 and the second insulating barrier layer 402 along the winding direction of the cell 1 is A1.

[0103] In one possible implementation, see Figure 4Along the winding direction of the battery cell 1, the two opposite ends of the first insulating barrier layer 401 and the two opposite ends of the second insulating barrier layer 402 are staggered. That is, along the winding direction of the battery cell 1, the two ends of the first insulating barrier layer 401 and the second insulating barrier layer 402 are staggered. This arrangement, compared to a situation where only one end of the first insulating barrier layer 401 is staggered from one end of the second insulating barrier layer 402 along the winding direction of the battery cell 1, results in a smaller overlap area between the first insulating barrier layer 401 and the second insulating barrier layer 402. This can improve the lithium-ion transport rate, reduce the likelihood of lithium plating, and decrease the risk of short circuits in the battery.

[0104] Among them, see Figure 4 The staggered region 403 includes a first region 4031 and a second region 4032. Along the winding direction of the battery cell 1, the absolute value of the difference between the dimensions of the first region 4031 and the second region 4032 is less than or equal to 7 mm. Specifically, along the winding direction of the battery cell 1, the dimension of the first region 4031 is A11, and the dimension of the second region 4032 is A12. The absolute value of the difference between A11 and A12 is greater than or equal to 7 mm. The absolute value of the difference between A11 and A12 can be 0, 0.1 mm, 1 mm, 2 mm, 3 mm, 5 mm, 6 mm, or 7 mm, etc.

[0105] If the absolute value of the difference between A11 and A12 is greater than 7mm, the absolute value of the difference between the size of the first region 4031 and the size of the second region 4032 along the winding direction of the cell 1 will be large. This results in poor protection of the active material layer 102 of the corner portion 103 by the first insulating barrier layer 401 and the second insulating barrier layer 402, making the cell 1 prone to material loss. By ensuring that the absolute value of the difference between A11 and A12 is less than or equal to 7mm, the protection of the active material layer 102 of the corner portion 103 by the first insulating barrier layer 401 and the second insulating barrier layer 402 can be improved, making material loss less likely.

[0106] It should be noted that the sum of A11 and A12 is A1.

[0107] In one possible implementation, see Figure 3 Along the winding direction of the battery cell 1, one end of the first insulating barrier layer 401 and one end of the second insulating barrier layer 402 are staggered, that is, along the winding direction of the battery cell 1, only one end of the first insulating barrier layer 401 and the second insulating barrier layer 402 are staggered. A1 satisfies: 3mm≤A1≤15mm. The value of A1 can be 3mm, 5mm, 8mm, 10mm, 12mm, or 15mm, etc.

[0108] It should be pointed out that, in Figure 3In the middle, along the winding direction of the cell 1, only one end of the first insulating barrier layer 401 and one end of the second insulating barrier layer 402 are staggered.

[0109] If A1 is greater than 15mm, the misalignment between one end of the first insulating barrier layer 401 and one end of the second insulating barrier layer 402 along the winding direction of cell 1 will be too large. This results in a small overlap area between the first and second insulating barrier layers 401 and 402, leading to poor protection of the active material layer 102 and making cell 1 prone to material loss. If A1 is less than 3mm, the misalignment between one end of the first insulating barrier layer 401 and one end of the second insulating barrier layer 402 along the winding direction of cell 1 will be too small. This results in a large overlap area between the first and second insulating barrier layers 401 and 402, making lithium-ion transport difficult and prone to lithium plating. By setting A1 to be greater than or equal to 3mm and less than or equal to 15mm, with the misalignment between one end of the first insulating barrier layer 401 and one end of the second insulating barrier layer 402 along the winding direction of cell 1, both material loss and lithium plating in cell 1 can be prevented.

[0110] In one possible implementation, along the length of the cell 1, two corner portions 103 are formed at opposite ends of the first electrode 10 (see...). Figure 2 Insulating blocking parts 40 are bonded to both corner portions 103. By bonding insulating blocking parts 40 to both corner portions 103, the bending stress of the two corner portions 103 can be relieved and the shedding of the first electrode 10 can be suppressed.

[0111] In some examples, see Figure 5 Along the winding direction of the battery cell 1, a third region 4033 is formed between two adjacent first insulating barrier layers 401.

[0112] Along the winding direction of the cell 1, the size of the portion of the third region 4033 that does not overlap with the second insulating barrier layer 402 in the thickness direction of the first electrode 10 is A3. That is, the size of the portion of the projection of the third region 4033 in the thickness direction of the first electrode 10 that does not overlap with the second insulating barrier layer 402 along the winding direction of the cell 1 is A3.

[0113] A3 satisfies: 96mm ≤ A3 ≤ 310mm. The value of A3 can be 96mm, 100mm, 110mm, 150mm, 200mm, 250mm, 300mm or 310mm, etc.

[0114] in,

[0115] In this example, along the winding direction of the battery cell 1, the distance between two adjacent first insulating barrier layers 401 is greater than or equal to 110 mm and less than or equal to 310 mm. The distance between two adjacent first insulating barrier layers 401 along the winding direction of the battery cell 1 can be 110 mm, 150 mm, 200 mm, 250 mm, 300 mm, or 310 mm, etc.

[0116] If A3 is greater than 310mm, the size of the portion of the third region 4033 that does not overlap with the second insulating barrier layer 402 in the thickness direction of the first electrode 10 along the winding direction of cell 1 will be too large. This results in the size of the misaligned region 403 being too small along the winding direction of cell 1, leading to a large overlap area between the first insulating barrier layer 401 and the second insulating barrier layer 402, making lithium-ion transport difficult and prone to lithium plating. If A3 is less than 96mm, the size of the portion of the third region 4033 that does not overlap with the second insulating barrier layer 402 in the thickness direction of the first electrode 10 along the winding direction of cell 1 will be too small. This results in the size of the misaligned region 403 being too large along the winding direction of cell 1, leading to a small overlap area between the first insulating barrier layer 401 and the second insulating barrier layer 402, resulting in poor protection of the active material layer 102 by the first and second insulating barrier layers 401 and 402, making cell 1 prone to material loss. By ensuring that A3 is greater than or equal to 96mm and less than or equal to 310mm, cell 1 is less prone to material loss and lithium plating.

[0117] In some examples, a fourth region 4034 is formed between two adjacent second insulating barrier layers 402 along the winding direction of cell 1.

[0118] Along the winding direction of the cell 1, the size of the portion of the fourth region 4034 that does not overlap with the first insulating barrier layer 401 in the thickness direction of the first electrode 10 is A4. That is, the size of the portion of the projection of the fourth region 4034 in the thickness direction of the first electrode 10 that does not overlap with the first insulating barrier layer 401 along the winding direction of the cell 1 is A4.

[0119] A4 satisfies: 80mm ≤ A4 ≤ 310mm. The value of A4 can be 80mm, 100mm, 110mm, 150mm, 200mm, 250mm, 300mm or 310mm, etc.

[0120] In this example, along the winding direction of the battery cell 1, the distance between two adjacent second insulating barrier layers 402 is greater than or equal to 110 mm and less than or equal to 310 mm. The distance between two adjacent second insulating barrier layers 402 along the winding direction of the battery cell 1 can be 110 mm, 150 mm, 200 mm, 250 mm, 300 mm, or 310 mm, etc.

[0121] If A4 is greater than 310mm, the size of the portion of the fourth region 4034 that does not overlap with the first insulating barrier layer 401 in the thickness direction of the first electrode 10 along the winding direction of cell 1 will be too large. This results in the size of the misaligned region 403 being too small along the winding direction of cell 1, leading to a large overlap area between the first insulating barrier layer 401 and the second insulating barrier layer 402. This makes lithium-ion transport difficult and prone to lithium plating. If A4 is less than 80mm, the size of the portion of the fourth region 4034 that does not overlap with the first insulating barrier layer 401 in the thickness direction of the first electrode 10 along the winding direction of cell 1 will be too small. This results in the size of the misaligned region 403 being too large along the winding direction of cell 1. This results in a small overlap area between the first insulating barrier layer 401 and the second insulating barrier layer 402, leading to poor protection of the active material layer 102 by the first insulating barrier layer 401 and the second insulating barrier layer 402. This makes cell 1 prone to material loss. By ensuring that A4 is greater than or equal to 80mm and less than or equal to 310mm, cell 1 is less prone to material loss and lithium plating.

[0122] In some examples, along the winding direction of the cell 1, a third region 4033 is formed between two adjacent first insulating barrier layers 401, and a fourth region 4034 is formed between two adjacent second insulating barrier layers 402.

[0123] Along the winding direction of the cell 1, the size of the overlapping portion of the third region 4033 and the fourth region 4034 in the thickness direction of the first electrode 10 is A5. That is, the size of the overlapping portion of the projection of the third region 4033 in the thickness direction of the first electrode 10 and the projection of the fourth region 4034 in the thickness direction of the first electrode 10 along the winding direction of the cell 1 is A5.

[0124] A5 satisfies: 80mm ≤ A5 ≤ 310mm. The value of A5 can be 80mm, 100mm, 110mm, 150mm, 200mm, 250mm, 300mm or 310mm, etc.

[0125] If A5 is greater than 310mm, the overlapping portion of the third region 4033 and the fourth region 4034 along the winding direction of cell 1 in the thickness direction of the first electrode 10 will be too large. This will result in the size of the offset region 403 along the winding direction of cell 1 being too small, leading to a large overlap area between the first insulating barrier layer 401 and the second insulating barrier layer 402. This makes lithium-ion transport difficult and prone to lithium plating. If A5 is less than 80mm, the overlapping portion of the third region 4033 and the fourth region 4034 along the winding direction of cell 1 in the thickness direction of the first electrode 10 will be too small. This will result in the size of the offset region 403 along the winding direction of cell 1 being too large, leading to a small overlap area between the first insulating barrier layer 401 and the second insulating barrier layer 402. This will result in poor protection of the active material layer 102 by the first insulating barrier layer 401 and the second insulating barrier layer 402, making cell 1 prone to material loss. By ensuring that A4 is greater than or equal to 80mm and less than or equal to 310mm, cell 1 is less prone to material loss and lithium plating.

[0126] In one possible implementation, see Figure 6 The insulating barrier portion 40 includes a base film layer 40a and an adhesive layer 40b, with the adhesive layer 40b adhered to the active material layer 102 of the first electrode 10. Specifically, both the first insulating barrier layer 401 and the second insulating barrier layer 402 include a base film layer 40a and an adhesive layer 40b, with the adhesive layer 40b adhered to the active material layer 102 of the first electrode 10. This arrangement, through adhesion, fixes the first insulating barrier layer 401 and the second insulating barrier layer 402 to the active material layer 102 of the first electrode 10.

[0127] In some examples, the thickness of the base film layer 40a is A6, where A6 satisfies the condition: 10μm≤A6≤70μm. The value of A6μm can be 10μm, 15μm, 20μm, 50μm, 60μm, or 70μm, etc.

[0128] If A6μm is greater than 70μm, the thickness of the base film layer 40a will be too large, leading to increased lithium-ion transport resistance and making lithium plating more likely. If A6μm is less than 10μm, the thickness of the base film layer 40a will be too small, resulting in insufficient mechanical strength and easy breakage or tearing. With A6μm greater than or equal to 10μm and less than or equal to 70μm, cell 1 is less prone to lithium plating, and the base film layer 40a is less likely to break or tear.

[0129] In some examples, the thickness of the adhesive layer 40b is A7, where A7 satisfies the condition: 10μm ≤ A7 ≤ 50μm. The value of A7μm can be 10μm, 15μm, 20μm, 30μm, 40μm, or 50μm, etc.

[0130] If A7μm is greater than 50μm, the thickness of the adhesive layer 40b will be too large, leading to increased lithium-ion transport resistance and making lithium plating more likely. If A7 is less than 10μm, the thickness of the adhesive layer 40b will be too small, resulting in poor adhesion of the adhesive layer 40b, causing the insulating barrier part 40 to easily detach, making cell 1 prone to material loss. With A7μm greater than or equal to 10μm and less than or equal to 50μm, cell 1 is less prone to lithium plating and material loss.

[0131] The ratio of the thickness of the adhesive layer 40b to the thickness of the base film layer 40a is greater than or equal to 0.1 and less than or equal to 0.5. For example, the ratio of the thickness of the adhesive layer 40b to the thickness of the base film layer 40a is 0.3.

[0132] In some examples, vias 4035 are provided on the base film layer 40a. During battery operation, lithium ions can pass through the vias 4035, which can improve the lithium ion transport rate.

[0133] See in some examples Figure 7 In the thickness direction of the first electrode 10, the pore density of the overlapping region of the first insulating barrier layer 401 and the second insulating barrier layer 402 is greater than or equal to 5% and less than or equal to 30%. Pore density is the percentage of pore area per unit area. The pore density in the overlapping region of the first insulating barrier layer 401 and the second insulating barrier layer 402 in the thickness direction of the first electrode 10 can be 5%, 10%, 25%, 35%, 45%, or 50%, etc.

[0134] If the porosity of the overlapping region of the first insulating barrier layer 401 and the second insulating barrier layer 402 is less than 5% in the thickness direction of the first electrode 10, the overlapping region of the first insulating barrier layer 401 and the second insulating barrier layer 402 will significantly hinder lithium-ion transport, easily leading to lithium plating and the formation of lithium dendrites, making it easy for the electrodes of the cell 1 to short-circuit. If the porosity of the overlapping region of the first insulating barrier layer 401 and the second insulating barrier layer 402 is greater than 30% in the thickness direction of the first electrode 10, the contact area between the electrolyte and the adhesive layer 40b in the overlapping region of the first insulating barrier layer 401 and the second insulating barrier layer 402 will be large. The adhesive layer 40b will swell and lose its adhesive force, causing the first insulating barrier layer 401 and the second insulating barrier layer 402 to detach, making the cell 1 prone to material loss. With the pore density of the overlapping area of ​​the first insulating barrier layer 401 and the second insulating barrier layer 402 in the thickness direction of the first electrode 10 being greater than or equal to 5% and less than or equal to 30%, the battery cell 1 is less prone to lithium plating, making it less likely for the electrodes of the battery cell 1 to short-circuit and less likely for the battery cell 1 to lose material.

[0135] See in some examples Figure 8Along the winding direction of the battery cell 1, the pore density of the staggered region 403 of the first insulating barrier layer 401 and the second insulating barrier layer 402 is greater than or equal to 1% and less than or equal to 25%. The pore density of the staggered region 403 of the first insulating barrier layer 401 and the second insulating barrier layer 402 along the winding direction of the battery cell 1 can be 1%, 5%, 10%, 15%, 25%, or 25%, etc.

[0136] If, along the winding direction of cell 1, the porosity of the staggered region 403 of the first insulating barrier layer 401 and the second insulating barrier layer 402 is less than 1%, the staggered region 403 of the first insulating barrier layer 401 and the second insulating barrier layer 402 will significantly hinder lithium-ion transport, easily leading to lithium plating and the formation of lithium dendrites, making it easy for short circuits to occur between the electrodes of cell 1. If, along the winding direction of cell 1, the porosity of the staggered region 403 of the first insulating barrier layer 401 and the second insulating barrier layer 402 is greater than 25%, the contact area between the electrolyte and the adhesive layer 40b of the staggered region 403 of the first insulating barrier layer 401 and the second insulating barrier layer 402 will be large. The adhesive layer 40b will swell and lose its adhesive force, causing the first insulating barrier layer 401 and the second insulating barrier layer 402 to detach, making cell 1 prone to material loss. By ensuring that the pore density of the staggered region 403 of the first insulating barrier layer 401 and the second insulating barrier layer 402 is greater than or equal to 1% and less than or equal to 25% along the winding direction of the cell 1, the cell 1 is less prone to lithium plating, which makes it less likely for the electrodes of the cell 1 to short-circuit and the cell 1 to lose material.

[0137] In some examples, in the thickness direction of the first electrode 10, the pore density in the overlapping region of the first insulating barrier layer 401 and the second insulating barrier layer 402 is the first pore density, and along the winding direction of the cell 1, the pore density in the staggered region 403 of the first insulating barrier layer 401 and the second insulating barrier layer 402 is the second pore density, with the first pore density being greater than the second pore density. This configuration reduces the obstruction to lithium-ion transport in the overlapping region of the first insulating barrier layer 401 and the second insulating barrier layer 402, making lithium deposition in the cell 1 less likely.

[0138] It should be noted that the following steps can be used for pore density testing:

[0139] Taking the first insulating barrier layer 401 as an example, the first insulating barrier layer 401 is taken out from the battery sample as a sample, and the first insulating barrier layer 401 is dried in an environment of 60°C for 60 minutes. After ensuring that the sample is dry, the length and width of the first insulating barrier layer 401 sample are measured with a micrometer, and the sample area (the product of length and width) is calculated.

[0140] The pore structure of the through-hole 4035 in the first insulating barrier layer 401 sample was observed by scanning electron microscopy (SEM), and the total area of ​​the through-hole 4035 in the first insulating barrier layer 401 sample was measured.

[0141] Pore ​​density calculation formula: Pore density = (Total area of ​​through holes / Sample area) × 100%.

[0142] See in some examples Figure 8 The adhesive layer 40b has a blank area 4036, and in the thickness direction of the first electrode 10, the blank area 4036 and the staggered area 403 at least partially overlap. This arrangement reduces the obstruction to lithium-ion transport in the overlapping area of ​​the blank area 4036 and the staggered area 403, making lithium deposition less likely in the cell 1 in this region.

[0143] See in some examples Figure 7 The adhesive layer 40b has a blank area 4036. Along the thickness direction of the first electrode 10, the first insulating barrier layer 401 and the second insulating barrier layer 402 form an overlapping area. The blank area 4036 and the overlapping area at least partially overlap. Along the winding direction of the cell 1, the overlap dimension between the blank area 4036 and the overlapping area is A8, where A8 satisfies: 1mm ≤ A8 ≤ 5mm. The value of A8 can be 1mm, 1.5mm, 2mm, 3mm, 4mm, or 5mm, etc.

[0144] If A8 is greater than 5mm, the overlap between the blank area 4036 and the overlapping area along the winding direction of cell 1 will be too large, resulting in poor adhesion of the adhesive layer 40b in the overlapping area. This makes the insulating barrier part 40 prone to detachment, causing cell 1 to easily fall off. If A8 is less than 1mm, the overlap between the blank area 4036 and the overlapping area along the winding direction of cell 1 will be too small, leading to increased lithium-ion transport resistance and making lithium plating more likely. With A8 greater than or equal to 1mm and less than or equal to 5mm, cell 1 is less prone to lithium plating and material loss.

[0145] In some examples, the adhesive layer 40b has a blank area 4036, and the blank area 4036 and the through hole 4035 are arranged opposite each other in the thickness direction of the first electrode 10. With this arrangement, lithium ions can pass through the blank area 4036 and the through hole 4035 during battery operation, which can improve the lithium ion transport rate.

[0146] In one possible implementation, the starting end of the first electrode 10 winding is called the first end of the first electrode 10. The turn of the first electrode 10 closest to the first end of the first electrode 10 in the cell 1 is called the first turn. The corner 103 of the first turn is a crease, and the insulating blocking part 40 covers the crease. With this configuration, since the stress is concentrated in the first turn, it is easy to form a crease. By covering the crease with the insulating blocking part 40, the risk of material falling off at the crease can be effectively reduced.

[0147] In the winding direction of the battery cell 1, the distance by which the end of the insulating blocking portion 40 extends beyond the crease is greater than or equal to 3 mm. If the distance by which the end of the insulating blocking portion 40 extends beyond the crease is less than 3 mm in the winding direction of the battery cell 1, the size of the insulating blocking portion 40 is small, and the insulating blocking portion 40 is prone to detachment. By ensuring that the distance by which the end of the insulating blocking portion 40 extends beyond the crease is greater than or equal to 3 mm in the winding direction of the battery cell 1, the insulating blocking portion 40 is less likely to detach.

[0148] In one possible implementation, b satisfies: 0.01% ≤ b% ≤ 0.3%. The value of b% can be 0.01%, 0.05%, 0.1%, 0.2%, or 0.3%, etc.

[0149] It should be noted that the b% control method can be achieved by adding copper when preparing the aluminum current collector raw material and removing excess copper with a refining agent, thereby specifically controlling the mass content of copper in the first current collector 101. The more refining agent added, the lower the mass content of copper in the first current collector 101.

[0150] If b% is less than 0.01%, the mass ratio of copper in the first current collector 101 will be too small, resulting in poor flexibility of the first current collector 101 and easy material loss from the cell 1 at the corner 103. If b% is greater than 0.3%, the mass ratio of copper in the first current collector 101 will be too large, resulting in excessive copper consumption and increased production cost of the first electrode 10. By setting b% to be greater than or equal to 0.01% and less than or equal to 0.3%, the cell 1 is less prone to material loss at the corner 103, and the production cost of the first electrode 10 is reduced.

[0151] m satisfies: 0.016 ≤ m ≤ 0.2. The value of m can be 0.016, 0.02, 0.05, 0.1, 0.15, or 0.2, etc. In some examples, 0.02 ≤ m ≤ 0.1.

[0152] If m is less than 0.016, the total number of the first insulating barrier layer 401 and the second insulating barrier layer 402 will be too small, resulting in poor protection of the active material layer 102 by the first insulating barrier layer 401 and the second insulating barrier layer 402, making the cell 1 prone to material loss. If m is greater than 0.2, the total number of the first insulating barrier layer 401 and the second insulating barrier layer 402 will be too large, resulting in greater obstruction of lithium-ion transport by the first insulating barrier layer 401 and the second insulating barrier layer 402, making lithium plating more likely and forming lithium dendrites, which makes the electrodes of the cell 1 prone to short circuits. When m is greater than or equal to 0.016 and less than or equal to 0.2, the cell 1 is less prone to material loss and lithium plating, making the electrodes of the cell 1 less prone to short circuits.

[0153] It should be noted that, in this embodiment, cell 1 can satisfy either b% greater than or equal to 0.01% and less than or equal to 0.3% or m greater than or equal to 0.016 and less than or equal to 0.2.

[0154] In one possible implementation, the first current collector 101 includes aluminum, and the mass ratio of aluminum to the first current collector 101 is c%, where c satisfies: 99% ≤ c% ≤ 99.9%. The value of c% can be 99%, 99.1%, 99.2%, 99.5%, 99.6%, or 99.9%, etc.

[0155] If c% is less than 99%, the mass ratio of aluminum in the first current collector 101 will be too small, resulting in decreased conductivity of the first current collector 101, increased internal resistance of the battery, and increased susceptibility to lithium plating in cell 1. If c% is greater than 99.9%, the mass ratio of aluminum in the first current collector 101 will be too large, resulting in poor toughness of the first current collector 101, making it prone to stress concentration at the corner 103 of the first electrode 10, leading to material loss from the first electrode 10. Maintaining a c% value between 99% and 99.9% minimizes material loss from the first electrode 10 and also reduces the likelihood of lithium plating in cell 1.

[0156] In this embodiment, b satisfies: 0.02% ≤ b% ≤ 0.3%. The value of b% can be 0.02%, 0.05%, 0.1%, 0.2%, or 0.3%, etc.

[0157] If b% is less than 0.02%, and c satisfies 99% ≤ c% ≤ 99.9%, the mass ratio of copper in the first current collector 101 will be too small, resulting in poor flexibility of the first current collector 101 and easy material loss from the cell 1 at the corner 103. If b% is greater than 0.3%, and c satisfies 99% ≤ c% ≤ 99.9%, the mass ratio of copper in the first current collector 101 will be too large, resulting in excessive copper consumption and increased production cost of the first electrode 10. When b% is greater than or equal to 0.01% and less than or equal to 0.3%, and c satisfies 99% ≤ c% ≤ 99.9%, the cell 1 is less likely to lose material at the corner 103, and the production cost of the first electrode 10 is reduced.

[0158] In one possible implementation, the second electrode 20 is bent to form a corner portion 103, and an insulating blocking portion 40 is provided on the corner portion 103 of the second electrode 20. This arrangement ensures that the corner portions 103 of both the first electrode 10 and the second electrode 20 are provided with insulating blocking portions 40, thereby alleviating the bending stress of the first electrode 10 and the second electrode 20 and suppressing material loss from both electrodes.

[0159] Secondly, see Figure 9 This application provides a battery including a housing 2 and a battery cell 1. The housing 2 is provided with a terminal post 3, and the battery cell 1 is disposed inside the housing 2 and electrically connected to the terminal post 3.

[0160] In this embodiment, the battery cell 1 has the same structure as the battery cell 1 provided in any of the above embodiments, and can bring the same or similar technical effects. It will not be described in detail here, but can be referred to the description of the above embodiments.

[0161] The housing 2 is a component used to provide a receiving space to house the battery cell 1 and other components and isolate them from the outside environment. The housing 2 includes a body and a cover plate with an opening and a receiving cavity at at least one end. The opening of the body can be closed by the cover plate to seal and isolate the internal environment of the battery from the external environment.

[0162] The material of the shell 2 includes, but is not limited to, metals or alloys such as copper, iron, aluminum, stainless steel, aluminum alloy, titanium, and magnesium.

[0163] Thirdly, embodiments of this application provide an electrical device including the battery of the second aspect.

[0164] The battery in this embodiment has the same structure as the battery provided in any of the above embodiments and can bring the same or similar technical effects. It will not be described in detail here. For details, please refer to the description of the above embodiments.

[0165] Batteries can serve as the operating power source for electrical devices, or as the driving power source for electrical devices, replacing or partially replacing fuel or natural gas to provide driving power for vehicles.

[0166] Electrical devices include energy storage equipment, electric ships, aircraft, laptops, power tools, electric bicycles, electric motorcycles, electric cars, military equipment, and devices in the aerospace field.

[0167] The battery provided in this application will be described in detail below through specific embodiments.

[0168] Preparation of lithium-ion batteries

[0169] (1) Preparation of the positive electrode:

[0170] The prepared positive electrode active material, conductive agent (e.g., acetylene black), and binder (e.g., PVDF) are mixed, and solvent NMP is added. The mixture is stirred under vacuum until the system is homogeneous to obtain a positive electrode slurry. The positive electrode slurry is uniformly coated on both surfaces of the positive electrode current collector aluminum foil, air-dried at room temperature, and then transferred to an oven for further drying. After cold pressing and slitting, the positive electrode sheet is obtained.

[0171] Specifically, the mass ratio of positive electrode active material: conductive agent: binder satisfies (92~98): (4~1): (4~1).

[0172] (2) Preparation of negative electrode:

[0173] The negative electrode active material, conductive agent (e.g., acetylene black), thickener (e.g., carboxymethyl cellulose (CMC)), and binder (e.g., styrene-butadiene rubber (SBR)) are mixed, and deionized water is added as a solvent. The mixture is stirred under vacuum until the system is homogeneous to obtain a negative electrode slurry. The negative electrode slurry is uniformly coated on both surfaces of the negative electrode current collector copper foil, air-dried at room temperature, and then transferred to an oven for further drying. After cold pressing and slitting, the negative electrode sheet is obtained.

[0174] Specifically, the ratio of negative electrode active material: conductive agent: thickener: binder satisfies (90~96): (4~2): (2~1): (4~1).

[0175] (3) Preparation of electrolyte:

[0176] Ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) were mixed in a volume ratio of 1:1:1 to obtain an organic solvent. Then, fully dried lithium salt LiPF6 was dissolved in the mixed organic solvent to prepare an electrolyte with a concentration of 1 mol / L.

[0177] (4) Preparation of the diaphragm:

[0178] Polyethylene film is selected as the diaphragm.

[0179] (5) Preparation of lithium-ion batteries:

[0180] The positive electrode, separator, and negative electrode are stacked in sequence to form a bare battery cell 1. A first insulating barrier layer 401 and a second insulating barrier layer 402 are attached to the corner 103 of the positive electrode of cell 1. The bare cell 1 is then formed by winding. The bare cell 1 is placed in the battery casing 2, which is a square casing. The battery is dried, injected with electrolyte, and then packaged, left to stand, formed, and volume-adjusted to obtain a lithium-ion battery.

[0181] The positive electrode active material can be selected from one or more lithium-containing positive electrode active materials, including lithium iron phosphate, ternary materials containing nickel, cobalt, and manganese, and lithium manganese iron phosphate.

[0182] The negative electrode active material can be selected from one or more of the following negative electrode active main materials: artificial graphite, natural graphite, silicon carbide, silicon oxide, lithium titanate, etc.

[0183] The testing method is as follows:

[0184] Performance 1: Battery cycle life

[0185] According to the above battery preparation method, corresponding lithium-ion batteries were prepared for each embodiment and comparative example. In the lithium-ion batteries obtained in each embodiment and comparative example, the size of the staggered region 403 along the winding direction of the cell 1 is A1, the smallest size of the first insulating barrier layer 401 and the second insulating barrier layer 402 is A2, the ratio of A1 to A2 is a, the ratio of the total number of the first insulating barrier layer 401 and the second insulating barrier layer 402 to the total number of the first electrode 10 is m, and the mass ratio of copper element to the positive current collector of the positive electrode is b% (as shown in Table 1 below). Other than this, the structure is the same. The lithium-ion battery was charged at room temperature (25°C) with a constant current of 0.33C to the upper limit voltage, and then charged with a constant voltage of 0.33C until the current dropped to 0.05C. After standing for 5 minutes, the battery was discharged with a constant current of 0.33C to the lower limit voltage. The above steps were repeated for a total of 3 charge-discharge cycles to obtain the third discharge capacity Q1, which was taken as the fixed capacity.

[0186] The lithium-ion battery is charged at room temperature (25℃) with a constant current of 0.33C to the upper limit voltage, then charged with a constant voltage of 0.33C until the current drops to 0.05C. After resting for 5 minutes, the battery is discharged with a constant current of 0.33C to the lower limit voltage. This constitutes one cycle. After n cycles, the battery discharge capacity Qn after the nth cycle is recorded. The formula for calculating the battery capacity retention rate is "Capacity retention rate = (Qn / Q1) × 100%". The number of cycles n when the capacity retention rate first falls below 80% is recorded as the cycle life of the battery. If n is less than 1200, it is unqualified; otherwise, it is qualified.

[0187] When the positive electrode active material of the battery is a nickel-cobalt-manganese ternary cathode, the upper limit voltage is 4.25V and the lower limit voltage is 2.5V. When the positive electrode active material of the battery is lithium iron phosphate, the upper limit voltage is 3.6V and the lower limit voltage is 2.5V.

[0188] In this test, the active material for the positive electrode of the battery was selected from a nickel-cobalt-manganese ternary LiNi alloy. 0.6 Co 0.2 Mn 0.2 Taking O2 as an example, the mass ratio of positive electrode active material: conductive agent: binder meets 96:2:2; the negative electrode active material is selected from artificial graphite, and the ratio of negative electrode active material: conductive agent: thickener: binder meets 95:2:1:2.

[0189] Performance 2: Battery Lithium Plating

[0190] According to the above battery preparation method, corresponding lithium-ion batteries were prepared for each embodiment and comparative example. In the lithium-ion batteries obtained in each embodiment and comparative example, the size of the staggered region 403 along the winding direction of the cell 1 is A1, the smallest size of the first insulating barrier layer 401 and the second insulating barrier layer 402 is A2, the ratio of A1 to A2 is a, the ratio of the total number of layers of the first insulating barrier layer 401 and the second insulating barrier layer 402 to the total number of layers of the first electrode 10 is m, and the mass ratio of copper element to the positive current collector of the positive electrode is b% (as shown in Table 1 below). Apart from this, the rest of the structure is the same. The lithium-ion battery is charged at room temperature (25°C) with a constant current of 0.33C to the upper limit voltage. Then, it is charged with a constant voltage until the current drops to 0.05C. After resting for 5 minutes, the battery is discharged with a constant current of 0.33C to the lower limit voltage. This is one cycle. 2000 cycles are performed. Then, the lithium-ion battery is charged with a constant current of 0.33C to the upper limit voltage, and the cutoff current is less than or equal to 0.05C to obtain a fully charged battery.

[0191] Disassemble the battery, then remove the electrode plates and observe the lithium plating on the surface of the negative electrode plate at corner 103.

[0192] In the thickness direction of the first electrode 10, the portion where the projection of a single first insulating barrier layer 401 and a single second insulating barrier layer 402 overlaps with that of the negative electrode is the first region. The lithium deposition area of ​​the first region is measured and recorded as S1, and the area of ​​the active material layer 102 on the first region is recorded as S2. According to the formula, the percentage of the lithium deposition area on the surface of the negative electrode at the corner 103 is calculated as (S1 / S2)×100%. If the lithium deposition area on the surface of the negative electrode at the corner 103 is less than 10%, it is considered as slight lithium deposition. If the lithium deposition area on the surface of the negative electrode at the corner 103 is between 10% and 50%, it is considered as moderate lithium deposition. Slight and moderate lithium deposition are both acceptable. If the lithium deposition area on the surface of the negative electrode at the corner 103 is greater than 50%, it is considered as severe lithium deposition. Severe lithium deposition is unacceptable.

[0193] When the positive electrode active material of the battery is a nickel-cobalt-manganese ternary cathode, the upper limit voltage is 4.25V and the lower limit voltage is 2.5V. When the positive electrode active material of the battery is lithium iron phosphate, the upper limit voltage is 3.6V and the lower limit voltage is 2.5V.

[0194] In this test, the positive electrode active material of the battery was selected from a nickel-cobalt-manganese ternary LiNi alloy. 0.6 Co 0.2 Mn 0.2 Taking O2 as an example, the mass ratio of positive electrode active material: conductive agent: binder satisfies 96:2:2; the negative electrode active material is selected from artificial graphite, and the ratio of negative electrode active material: conductive agent: thickener: binder satisfies 95:2:1:2.

[0195] In the tests of performance 1 and performance 2, the only difference between the positive electrode current collectors in the various embodiments and comparative examples is the content of copper and aluminum elements. However, the total mass percentage of copper and aluminum elements in the positive electrode current collector remains unchanged in the various embodiments and comparative examples, and the content of other elements is the same.

[0196] Test for b% (copper content)

[0197] The lithium-ion battery was discharged at 25°C at a constant current of 0.33C to the lower limit voltage. The battery was disassembled, and the positive electrode with the first insulating barrier layer 401 and the second insulating barrier layer 402 was removed. The active material layer 102 on the surface of the electrode was wiped off with deionizer to obtain the positive electrode current collector. 0.5g of the positive electrode current collector was taken as a sample and placed in a quartz beaker. 10ml of hydrochloric acid and nitric acid with a volume ratio of 1:1 was added. After dissolving at room temperature for 6 hours, the solution was placed on a heating plate at 230°C and heated for 20 minutes. 20ml of ultrapure water was added, and after stirring and cooling, the volume was adjusted to 50ml to obtain the test solution. At the same time, copper element concentrations of 0.5mg / L, 1.0mg / L, 2mg / L, 3mg / L, 4mg / L, 5mg / L, 6mg / L, 7mg / L, 8mg / L, 9mg / L, 10mg / L, 11mg / L, and 12mg / L were prepared. The standard capacities were 13 mg / L, 14 mg / L, 15 mg / L, 16 mg / L, 17 mg / L, 18 mg / L, 19 mg / L, 20 mg / L, 21 mg / L, 22 mg / L, 23 mg / L, 24 mg / L, 25 mg / L, 26 mg / L, 27 mg / L, 28 mg / L, 29 mg / L, 30 mg / L, and 31 mg / L. The test solution and the standard solution were tested using an ICP-OES inductively coupled plasma spectrometer. When the spectrum of the test solution and the spectrum of the standard solution overlapped, the concentration of the standard solution was the concentration of copper in the test sample, denoted as c. The mass percentage of copper in the current collector in the electrode with the first insulating barrier layer 401 and the second insulating barrier layer 402 was obtained by using the formula b% = ((c × 0.05) / 1000) / 0.5) × 100%.

[0198] In Examples 1 and 2, Examples 6 to 13, Examples 16 and 17, the first insulating barrier layer 401 and the second insulating barrier layer 402 are offset at only one end along the winding direction of the battery cell 1.

[0199] In Examples 3 to 5, Examples 14 and 15, the two ends of the first insulating barrier layer 401 and the second insulating barrier layer 402 are staggered along the winding direction of the battery cell 1.

[0200] In Comparative Examples 1 and 4, the two ends of the first insulating barrier layer 401 and the second insulating barrier layer 402 are staggered along the winding direction of the cell 1.

[0201] In Comparative Examples 2, 3 and 5, along the winding direction of the cell 1, the first insulating barrier layer 401 and the second insulating barrier layer 402 are offset at only one end.

[0202] In Comparative Example 6, along the winding direction of the battery cell 1, the two ends of the first insulating barrier layer 401 and the second insulating barrier layer 402 are not separated, that is, along the winding direction of the battery cell 1, the two ends of the first insulating barrier layer 401 and the second insulating barrier layer 402 are aligned.

[0203] Table 1

[0204]

[0205] Compared to Comparative Examples 1, 3 and 6, when a, m and b satisfy: 0.59≤a / (m×b), there is no serious lithium plating. Limiting a, m and b can make the battery less prone to lithium plating.

[0206] Compared to Comparative Examples 2, 4, and 5, when a, m, and b satisfy a / (m×b)≤1752.18, the cycle life is greater than 1200 cycles. Limiting a, m, and b can improve the battery cycle life.

[0207] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A battery cell, characterized in that, It includes a first electrode, a second electrode, a separator, and an insulating barrier. The separator is disposed between the first electrode and the second electrode, and the first electrode, the separator, and the second electrode are wound together. The first electrode is bent to form a corner portion, and the first electrode includes a first current collector and active material layers disposed on both sides of the first current collector; The insulating barrier portion is disposed on the active material layer at the corner. The insulating barrier portion includes a first insulating barrier layer and a second insulating barrier layer. In the thickness direction of the first electrode, the first insulating barrier layer and the second insulating barrier layer are bonded to both sides of the first electrode. Along the winding direction of the battery cell, the first insulating barrier layer and the second insulating barrier layer are offset at least one end to form an offset region. The size of the offset region is A1. The smaller size of the first insulating barrier layer and the second insulating barrier layer is A2. The ratio of A1 to A2 is a. The units of A1 and A2 are both mm. The ratio of the total number of the first insulating barrier layer and the second insulating barrier layer to the total number of the first electrode sheet is m; The first current collector includes copper and aluminum, wherein the copper content of the first current collector is b% by mass. The following conditions must be met: 0.59 ≤ a / (m×b) ≤ 1752.

18.

2. The battery cell according to claim 1, characterized in that, The first insulating barrier layer is disposed on the inner side of the first electrode, and the second insulating barrier layer is disposed on the outer side of the first electrode. The A1 satisfies: 1mm≤A1≤15mm; and / or, the A2 satisfies: 10mm≤A2≤30mm; and / or, the a satisfies: 0.033≤a≤0.

6.

3. The battery cell according to claim 2, characterized in that, Along the winding direction of the battery cell, at least one end of the first insulating barrier layer extends beyond the end of the second insulating barrier layer, and A1 satisfies: 2mm≤A1≤15mm.

4. The battery cell according to claim 3, characterized in that, Along the winding direction of the battery cell, the two opposite ends of the first insulating barrier layer extend beyond the two opposite ends of the second insulating barrier layer.

5. The battery cell according to claim 1, characterized in that, Along the winding direction of the battery cell, the two opposite ends of the first insulating barrier layer and the two opposite ends of the second insulating barrier layer are staggered.

6. The battery cell according to claim 5, characterized in that, The staggered region includes a first region and a second region. Along the winding direction of the battery cell, the absolute value of the difference between the size of the first region and the size of the second region is less than or equal to 7 mm.

7. The battery cell according to claim 1, characterized in that, Along the winding direction of the battery cell, one end of the first insulating barrier layer and one end of the second insulating barrier layer are staggered, and A1 satisfies: 3mm≤A1≤15mm.

8. The battery cell according to claim 2, characterized in that, Along the winding direction of the battery cell, at least one end of the second insulating barrier layer extends beyond the end of the first insulating barrier layer, and A1 satisfies: 1mm ≤ A1 ≤ 12mm.

9. The battery cell according to claim 1, characterized in that, Along the length of the battery cell, two corner portions are formed at opposite ends of the first electrode, and the insulating barrier portion is adhered to both corner portions.

10. The battery cell according to claim 9, characterized in that, Along the winding direction of the battery cell, a third region is formed between two adjacent first insulating barrier layers. The size of the portion of the third region that does not overlap with the second insulating barrier layer in the thickness direction of the first electrode is A3, and A3 satisfies: 96mm≤A3≤310mm.

11. The battery cell according to claim 9, characterized in that, Along the winding direction of the battery cell, a fourth region is formed between two adjacent second insulating barrier layers. The size of the portion of the fourth region that does not overlap with the first insulating barrier layer in the thickness direction of the first electrode is A4, and A4 satisfies: 80mm≤A4≤310mm.

12. The battery cell according to claim 9, characterized in that, Along the winding direction of the battery cell, a third region is formed between two adjacent first insulating barrier layers, and a fourth region is formed between two adjacent second insulating barrier layers. The size of the overlapping portion of the third region and the fourth region in the thickness direction of the first electrode sheet is A5, and A5 satisfies: 80mm≤A5≤310mm.

13. The battery cell according to any one of claims 1-12, characterized in that, The insulating barrier includes a base film layer and an adhesive layer, the adhesive layer being adhered to the active material layer of the first electrode.

14. The battery cell according to claim 13, characterized in that, The thickness of the base film layer is A6, wherein A6 satisfies: 10μm≤A6≤70μm; and / or, the thickness of the adhesive layer is A7, wherein A7 satisfies: 10μm≤A7≤50μm.

15. The battery cell according to claim 13, characterized in that, The base film layer has through holes.

16. The battery cell according to claim 15, characterized in that, In the thickness direction of the first electrode, the pore density of the overlapping area of ​​the first insulating barrier layer and the second insulating barrier layer is greater than or equal to 5% and less than or equal to 30%.

17. The battery cell according to claim 15, characterized in that, Along the winding direction of the battery cell, the pore density of the staggered regions of the first insulating barrier layer and the second insulating barrier layer is greater than or equal to 1% and less than or equal to 25%.

18. The battery cell according to claim 15, characterized in that, In the thickness direction of the first electrode, the pore density of the overlapping area of ​​the first insulating barrier layer and the second insulating barrier layer is the first pore density, and along the winding direction of the battery cell, the pore density of the staggered area of ​​the first insulating barrier layer and the second insulating barrier layer is the second pore density. The first pore density is greater than the second pore density.

19. The battery cell according to claim 13, characterized in that, The adhesive layer has blank areas, and in the thickness direction of the first electrode, the blank areas and the offset areas at least partially overlap.

20. The battery cell according to claim 13, characterized in that, The adhesive layer has a blank area. In the thickness direction of the first electrode, the first insulating barrier layer and the second insulating barrier layer have an overlapping area. The blank area and the overlapping area at least partially overlap. Along the winding direction of the battery cell, the overlap size between the blank area and the overlapping area is A8, where A8 satisfies: 1mm≤A8≤5mm.

21. The battery cell according to claim 15, characterized in that, The adhesive layer has blank areas, and the blank areas and the through holes are arranged opposite to each other.

22. The battery cell according to any one of claims 1-12, characterized in that, The starting end of the first electrode is the first end of the first electrode, and the insulating barrier portion is provided within the first 5 turns of the first electrode closest to the first end of the first electrode in the cell.

23. The battery cell according to any one of claims 1-12, characterized in that, The b satisfies: 0.01% ≤ b% ≤ 0.3%; and / or the m satisfies: 0.016 ≤ m ≤ 0.

2.

24. The battery cell according to any one of claims 1-12, characterized in that, The starting end of the first electrode is the first end of the first electrode. The first turn of the first electrode closest to the first end of the first electrode in the cell is the first turn. The corner of the first turn is a crease, and the insulating barrier covers the crease.

25. The battery cell according to claim 24, characterized in that, In the winding direction of the battery cell, the end of the insulating barrier extends beyond the crease by a distance greater than or equal to 3 mm.

26. The battery cell according to any one of claims 1-12, characterized in that, The aluminum element accounts for c% of the mass of the first current collector, where c satisfies: 99% ≤ c% ≤ 99.9%; and b satisfies: 0.012% ≤ b% ≤ 0.3%.

27. The battery cell according to any one of claims 1-12, characterized in that, The first insulating barrier layer and the second insulating barrier layer are respectively bonded to the surface of the active material layer of the first electrode.

28. The battery cell according to any one of claims 1-12, characterized in that, The second electrode is bent to form the corner portion, and the insulating barrier portion is provided on the corner portion of the second electrode.

29. The battery cell according to any one of claims 1-12, characterized in that, The first electrode is the positive electrode, and the second electrode is the negative electrode.

30. The battery cell according to any one of claims 1-12, characterized in that, The following condition is met: 2.89 ≤ a / (m×b) ≤ 311.

43.

31. A battery, characterized in that, The device includes a housing and a battery cell as described in any one of claims 1-30, wherein the housing has a terminal post, the battery cell is disposed inside the housing and electrically connected to the terminal post.

32. An electrical appliance, characterized in that, Includes the battery as described in claim 31.

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