Battery

Abstract

The invention provides a battery. The battery comprises a linear first electrode and a linear second electrode, and an insulating layer located between the first electrode and the second electrode. The first electrode comprises a first current collector extending in the first direction and a first electrode membrane formed on the outer side of the first current collector. The second electrode comprises a second current collector extending in the first direction and a second electrode diaphragm formed on the outer side of the second current collector. The first electrode and the second electrode are arranged in a winding manner. The first electrode has a first cross section perpendicular to the first direction, the second electrode has a second cross section perpendicular to the first direction, the product of the perimeter of the first cross section and the length of the first electrode is A, and the product of the perimeter of the second cross section and the length of the first electrode is B. A and B satisfy 0.5 < = A / B < = 1.2.

Description

Technical Field

[0001] This application relates to the field of battery technology, specifically to a battery. Background Technology

[0002] Lithium-ion batteries (such as lithium-ion pouch batteries) are a type of rechargeable high-energy battery. Due to their significant advantages such as high energy density, low self-discharge rate, high charging efficiency, long cycle life and no memory effect, they have been increasingly widely used in consumer electronics, aerospace, energy storage and new energy vehicles.

[0003] In recent years, with the upgrading of smart wearable products, there has been a greater demand for the flexibility and bendability of batteries. However, most commercially available lithium-ion batteries are cylindrical, steel-cased, or square pouch cells, and their internal battery cells are usually stacked or wound. These batteries cannot be flexible and bendable, which has played a limiting role in the development of various types of portable devices. Summary of the Invention

[0004] In view of this, embodiments of this application provide a battery to meet the requirements of battery flexibility and bendability.

[0005] In a first aspect, embodiments of this application provide a battery comprising a linear first electrode and a linear second electrode, wherein an insulating layer is disposed between the first electrode and the second electrode, the first electrode being a positive electrode and the second electrode being a negative electrode.

[0006] The first electrode includes a first current collector extending along a first direction and a first electrode diaphragm formed on the outer side of the first current collector. The second electrode includes a second current collector extending along the first direction and a second electrode diaphragm formed on the outer side of the second current collector. The first electrode and the second electrode are arranged in a wound manner.

[0007] The first electrode has a first cross-section perpendicular to the first direction, and the second electrode has a second cross-section perpendicular to the first direction. The product of the perimeter of the first cross-section and the length of the first electrode is A, and the product of the perimeter of the second cross-section and the length of the first electrode is B. A and B satisfy 0.5 ≤ A / B ≤ 1.2.

[0008] In some embodiments, the perimeter P1 of the first cross-section is 0.25 mm to 2.5 mm. And / or, the perimeter P2 of the second section is 0.3 mm to 3.0 mm. And / or, the length L1 of the first electrode along the first direction is 10 mm to 800 mm. And / or, the length L2 of the second electrode along the first direction is 11 mm to 801 mm; And / or, A satisfies: 15 mm 2≤A≤400 mm 2 ; And / or, B satisfies: 30 mm 2 ≤B≤400 mm 2 .

[0009] In some embodiments, the first current collector includes a first core material and a first conductive element wound around the first core material. Further, the first conductive element includes a plurality of first segments connected to each other. A first recess is formed on the surface of the first current collector, and the first recess is formed between two adjacent first segments of the first conductive element. And / or, the first conductive element covers the side of the first core material; And / or, the second current collector includes a second core material and a second conductive element wound around the second core material; further, the second conductive element includes a plurality of second segments connected to each other; a second recess is formed on the surface of the second current collector, and the second recess is formed between two adjacent second segments of the second conductive element. And / or, the second conductive element covers the side of the second core material.

[0010] In some embodiments, the diameter of the cross-section of the first core material perpendicular to the first direction is d1, and the diameter of the cross-section of the first conductive element perpendicular to the first direction is d2. d1 and d2 satisfy the following: the diameter ratio is 2 ≤ d1 / d2 ≤ 100, wherein d1 satisfies: 0.05 mm ≤ d1 ≤ 1 mm, and / or d2 satisfies: 0.01 mm ≤ d2 ≤ 0.5 mm; and / or The diameter of the cross section of the second core material perpendicular to the first direction is d3, and the diameter of the cross section of the second conductive element perpendicular to the first direction is d4. d3 and d4 satisfy: 2≤d3 / d4≤100, where d3 satisfies: 0.05 mm≤d3≤1 mm, and / or d4 satisfies: 0.01 mm≤d4≤0.5 mm.

[0011] In some embodiments, the material of the first core material and / or the material of the second core material includes one or more of polymer resin, rubber, and inorganic materials; further, Polymer resins include polyethylene terephthalate (PET), polyvinyl chloride (PVC), high-density polyethylene (HDPE), epoxy resin, and polypropylene (PP), and / or Inorganic materials include at least one of alumina, silicon dioxide, carbon black, and graphite.

[0012] In some embodiments, at least one of the first conductive element and the second conductive element is made of one or more of the following materials: stainless steel, aluminum, nickel, titanium, baked carbon, copper, stainless steel surface-treated with carbon, nickel, titanium, or silver, aluminum-cadmium alloy, non-conductive polymer surface-treated with a conductive material, or conductive polymer; further, Conductive materials include one or more of polyacetylene, polyaniline, polypyrrole, polythiophene, polysulfide, indium tin oxide (ITO), silver, palladium, and nickel, and / or Conductive polymers include one or more of polyacetylene, polyaniline, polypyrrole, polythiophene, and polysulfide.

[0013] In some embodiments, along the second direction, the thickness h1 of the first electrode film and the thickness h2 of the second electrode film satisfy: 0.9 ≤ h1 / h2 ≤ 1.1; and / or Along the first direction, the length of the first electrode is L1, and the length of the second electrode is L2, where L1 < L2, preferably. 0.5 mm ≤ (L2-L1) ≤ 10 mm, where The second direction is perpendicular to the first direction; and / or The material of at least one of the first and second current collectors includes one or more of the following: stainless steel, aluminum, nickel, titanium, baked carbon, copper, stainless steel surface-treated with carbon, nickel, titanium, or silver, aluminum-cadmium alloy, non-conductive polymer surface-treated with a conductive material, or conductive polymer; furthermore, Conductive materials include one or more of polyacetylene, polyaniline, polypyrrole, polythiophene, polysulfide, indium tin oxide (ITO), silver, palladium, and nickel, and / or Conductive polymers include one or more of polyacetylene, polyaniline, polypyrrole, polythiophene, and polysulfide.

[0014] In some embodiments, at least one of the first electrode film and the second electrode film is provided with at least one groove, preferably, the depth h3 of the groove is 2 μm to 50 μm, and / or, the spacing L3 between adjacent grooves is ≥0.05 mm, and / or The angle α between the groove and the first direction is 0° to 60°; and / or, The grooves are arranged in an array along the periphery of the first electrode film and / or the second electrode film, or the grooves are spirally arranged around the axis of the first electrode or the second electrode.

[0015] In some embodiments, the second electrode film includes a second material, which includes at least one of natural graphite, artificial graphite, carbonaceous material, silicon-carbon composite material, or silicon-oxygen composite material; and / or, The first electrode film includes a first material, which includes lithium cobalt oxide, lithium manganese oxide, lithium iron phosphate, lithium manganese iron phosphate, lithium manganese phosphate, ternary materials, and Li. a1 Co x1 M1 k1 O 2、 Li a2 Ni x2 Co y2D z2 M2 k2 At least one of O2, wherein 0.85≤a1≤1.1, 0.85≤a2≤1.1, 0.85≤x1≤1.05, 0.3≤x2≤0.98, 0≤y2≤0.5, 0≤z2≤0.5, 0≤k1≤0.15, 0≤k2≤0.15; D includes at least one of Mn and Al. M1 includes at least one of Al, Mg, Ti, Zr, Y, La, W, B, Nb, and Mn. M2 includes at least one of Al, Mg, Ti, Zr, Y, La, W, B, Nb, and Mn.

[0016] In some embodiments, an insulating layer surrounds the surface of the first electrode diaphragm facing away from the first current collector; or The insulating layer includes a first sub-insulating layer and a second sub-insulating layer. The first sub-insulating layer is disposed on the surface of the first electrode diaphragm that is away from the first current collector, and the second sub-insulating layer is disposed on the surface of the second electrode diaphragm that is away from the second current collector.

[0017] The battery provided by this invention includes a first electrode and a second electrode extending along a first direction, and the first electrode and the second electrode are wound in an alternating contact manner, thereby effectively improving the flexibility of the battery and making it bendable. In related technologies, stacked or wound cells are prone to electrode breakage or powder shedding during bending due to excessive bending stress. Furthermore, the shear force generated during bending directly damages the adhesion between the electrode and the separator, leading to misalignment of the positive and negative electrodes and the separator, which can easily cause short circuits. The battery provided by this invention connects the first and second electrodes through alternating contact winding, i.e., through "line contact," eliminating the need for shear force-bearing joints or bonding sections. Therefore, misalignment, breakage, or powder shedding of the positive and negative electrodes and the separator due to shear force is avoided.

[0018] Furthermore, by controlling the ratio between the product A of the first cross-section and length of the first electrode and the product B of the second cross-section and length of the second electrode, i.e., controlling the ratio between the surface areas of the first electrode and the second electrode, the NP ratio of the first electrode and the second electrode can be guaranteed. This ensures that the number of lithium intercalation sites on the second electrode is always greater than the total number of lithium ions that the first electrode can provide, providing sufficient space for lithium ion intercalation, increasing the overpotential for lithium plating, and preventing and mitigating the situation where the concentration of lithium ions in the cell is too high due to the excessive surface area of ​​the first electrode, which in turn leads to lithium plating on the second electrode.

[0019] Furthermore, by controlling the ratio between the surface areas of the first and second electrodes—that is, the surface area of ​​the second electrode being larger than that of the first electrode—the local true current density of the first electrode is directly reduced. This provides a wider space for rapid lithium-ion insertion, reduces concentration polarization and electrochemical polarization, thereby improving the battery's peak charging rate and ensuring safety during fast charging. Moreover, having a larger surface area for the second electrode than the first electrode also avoids a series of side reactions caused by excessively low potential at the second electrode, such as violent electrolyte reduction.

[0020] Finally, the first electrode and the second electrode are wound together in an alternating manner, with the surface area of ​​the second electrode being larger than that of the first electrode. This allows the second electrode to occupy more physical space within the limited cross-sectional area of ​​the battery, thus reserving extra space for the expansion of the second electrode, accommodating the expansion of the second electrode, buffering the internal stress of the second electrode, and preventing powder shedding caused by repeated expansion. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the drawings only show some embodiments of the present invention and should not be considered as a limitation of the scope. It should also be understood that the same or similar reference numerals are used in the drawings to represent the same or similar elements. Furthermore, it should be understood that the drawings are merely schematic, and the dimensions and scale of the elements in the drawings are not necessarily precise.

[0022] Figure 1 This is a schematic diagram of the structure of a battery according to an embodiment of this application.

[0023] Figure 2 This is a schematic diagram of the structure of the first electrode according to an embodiment of this application.

[0024] Figure 3 This is a cross-sectional schematic diagram of the second electrode according to an embodiment of this application.

[0025] Figure 4 This is a schematic diagram of the structure of a first current collector according to an embodiment of this application.

[0026] Figure 5 This is a schematic diagram of the structure of a second current collector according to an embodiment of this application.

[0027] Figure 6 This is a structural schematic diagram of a cross-section of a battery according to an embodiment of this application.

[0028] Figure 7 This is another structural schematic diagram of a cross-section of a battery according to one embodiment of this application.

[0029] Figure 8This is a schematic diagram of the structure of a battery cell according to an embodiment of this application.

[0030] Figure 9 This is a three-dimensional structural schematic diagram of the first electrode according to an embodiment of this application.

[0031] Figure label: 10. Battery; 11. Casing; 12. Cell; 121. First electrode; 1211. First current collector; 1211a. First recess; 1211b. First core material; 1211c. First conductive element; 1212. First electrode diaphragm; 1214. Groove; 122. Second electrode; 1221. Second current collector; 1221a. Second recess; 1221b. Second core material; 1221c. Second conductive element; 1222. Second electrode diaphragm; 123. Insulating layer; 1231. First sub-insulating layer; 1232. Second sub-insulating layer; 124. First adhesive layer; 125. Second adhesive layer. Detailed Implementation

[0032] The technical solutions in 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, and not all embodiments.

[0033] In recent years, with the upgrading of smart wearable products, there has been a greater demand for the flexibility and bendability of batteries. However, most commercially available lithium-ion batteries are cylindrical, steel-cased, or square pouch cells, and their internal battery cells are usually stacked or wound. These batteries cannot be flexible and bendable, which has played a limiting role in the development of various types of portable devices.

[0034] The following is for reference. Figures 1 to 9 The battery 10 provided in the embodiments of this application will be described by way of example.

[0035] According to one embodiment, the battery 10 of this application includes a linear first electrode 121 and a linear second electrode 122, with an insulating layer 123 disposed between the first electrode 121 and the second electrode 122. The insulating layer 123 is used to prevent short circuits from occurring when the first electrode 121 and the second electrode 122 come into contact. The first electrode 121 and the second electrode 122 have opposite polarities. In one example, the first electrode 121 may be a positive electrode, and the second electrode 122 may be a negative electrode.

[0036] The first electrode 121 includes a first current collector 1211 extending along a first direction and a first electrode diaphragm 1212 formed on the outer side of the first current collector 1211. The second electrode 122 includes a second current collector 1221 extending along a first direction and a second electrode diaphragm 1222 formed on the outer side of the second current collector 1221. The first electrode 121 and the second electrode 122 are arranged in a wound manner. In one example, the first direction may be, for example, the length direction of the electrode. Figures 1 to 3 , Figure 8 and Figure 9 As shown, in one example, the first electrode 121 and the second electrode 122 extend in the length direction and are spirally wound together, such that the first electrode 121 and the second electrode 122 are alternately positioned in contact with each other. In this text, "spiral" can be used synonymously with "helix," specifically referring to a shape that is wound in a staggered manner within a certain range, and usually referring to a structure similar to the shape of a common spring.

[0037] It should be noted that in this application, the first electrode 121 and the second electrode 122 of the battery 10 are alternately aligned and parallel to each other on the same horizontal plane, and it is not a case where one of the first electrode 121 and the second electrode 122 is surrounded by the other.

[0038] The first electrode 121 has a first cross-section perpendicular to the first direction, and the second electrode 122 has a second cross-section perpendicular to the first direction. The product of the perimeter of the first cross-section and the length of the first electrode 121 is A, and the product of the perimeter of the second cross-section and the length of the first electrode 121 is B. A and B satisfy 0.5 ≤ A / B ≤ 1.2, for example, 0.6, 0.7, 0.8, 0.9, 1, or 1.1. In one example, the first direction is the length direction of the battery 10, so the product of the perimeter of the first cross-section of the first electrode 121 and the length of the first electrode 121 is the surface area of ​​the first electrode 121, and the product of the perimeter of the second cross-section of the second electrode 122 and the length of the second electrode 122 is the surface area of ​​the second electrode 122.

[0039] In one example, the first electrode 121 and / or the second electrode 122 may be cable-like, for example, the first current collector 1211 may be tubular, with a first electrode diaphragm 1212 surrounding the outer surface of the first current collector 1211, and the second current collector 1221 may be tubular, with a second electrode diaphragm 1222 surrounding the outer surface of the second current collector 1221. Furthermore, the radius of the first cross-section of the first electrode 121 is much smaller than the length of the first electrode 121 along the first direction; for example, the ratio of the length of the first electrode 121 along the first direction to the radius of the first cross-section of the first electrode 121 is greater than 5. Similarly, the radius of the second cross-section of the second electrode 122 is much smaller than the length of the second electrode 122 along the first direction; for example, the ratio of the length of the second electrode 122 along the first direction to the radius of the second cross-section of the second electrode 122 is greater than 5.

[0040] According to the technical solution of this application, the battery 10 includes a first electrode 121 and a second electrode 122 extending along a first direction. The first electrode 121 and the second electrode 122 are wound together in an alternating contact manner, which can effectively improve the flexibility of the battery 10 and make the battery 10 meet the requirements of bendability. In the related art, when the stacked or wound cells 12 are bent, the electrode sheets are prone to breakage or powder shedding due to excessive bending stress. Moreover, the shear force generated during the bending process will directly destroy the bonding force between the electrode sheets and the separator, resulting in the risk of misalignment of the positive and negative electrode sheets and the separator, which may lead to short circuits between the positive and negative electrodes. The battery 10 provided by this invention uses the first electrode 121 and the second electrode 122 to be wound together in an alternating contact manner, that is, through a "line contact" necklace of alternating contact winding. There is no connecting adhesive section that needs to withstand shear force. Therefore, it will not be as prone to misalignment of the positive and negative electrodes and the separator, or breakage or powder shedding of the positive and negative electrodes due to shear force as existing stacked or wound cells.

[0041] Furthermore, by controlling the ratio between the product A of the first cross-section and length of the first electrode 121 and the product B of the second cross-section and length of the second electrode 122, that is, by controlling the ratio between the surface area of ​​the first electrode 121 and the surface area of ​​the second electrode 122, the NP ratio of the first electrode 121 and the second electrode 122 can be guaranteed. This ensures that the number of lithium intercalation sites on the second electrode 122 is always greater than the total amount of lithium ions that the first electrode 121 can provide, providing sufficient space for lithium ion intercalation, increasing the overpotential for lithium plating, and preventing the lithium ion concentration in the cell 12 from being too high due to the excessive surface area of ​​the first electrode 121, which would lead to lithium plating on the second electrode 122.

[0042] Furthermore, by controlling the ratio between the surface areas of the first electrode 121 and the second electrode 122—that is, the surface area of ​​the second electrode 122 being greater than that of the first electrode 121—the local true current density of the first electrode 121 is directly reduced. This provides a wider range of sites for rapid lithium-ion insertion, reduces concentration polarization and electrochemical polarization, thereby improving the peak charging rate of the battery 10 and ensuring safety during fast charging. Moreover, the larger surface area of ​​the second electrode 122 compared to the first electrode 121 also avoids a series of side reactions caused by excessively low potential of the second electrode 122, such as violent electrolyte reduction.

[0043] Finally, the first electrode 121 and the second electrode 122 are wound together in an alternating manner, and the surface area of ​​the second electrode 122 is larger than that of the first electrode 121. This allows the second electrode 122 to occupy more physical space within the limited cross-sectional area of ​​the battery 10, thus reserving extra space for the expansion of the second electrode 122, accommodating the expansion of the second electrode 122, buffering the internal stress of the second electrode 122, and avoiding powder shedding caused by repeated expansion.

[0044] refer to Figures 1 to 3 , Figure 6 and Figure 7 In one example, the battery 10 includes a first electrode 121, a second electrode 122, and a housing 11 for accommodating the first electrode 121, the second electrode 122, an insulating layer 123, and an electrolyte. In one example, the housing 11 may be made of, for example, a metal layer and a resin layer, with the resin layer located inside the metal layer. The metal layer may be, for example, aluminum, copper, stainless steel, or titanium alloy. The resin layer may be, for example, polypropylene, polyethylene, or polybutene.

[0045] In one example, the electrolyte in battery 10 includes a lithium salt and a non-aqueous solvent. The lithium salt may include, but is not limited to, at least one of: lithium hexafluorophosphate, lithium bis(trifluoromethanesulfonyl)imide LiN(CF3SO2)2 (LiTFSI), lithium bis(fluorosulfonyl)imide Li(N(SO2F)2) (LiFSI), lithium bis(oxalatoborate)borate LiB(C2O4)2 (LiBOB), lithium difluorooxalatoborate LiBF2(C2O4) (LiDFOB), LiNO3, LiClO4, LiB(C6H5)4, LiCH3SO3, LiCF3SO3, LiC(SO2CF3)3, and Li2SiF6. This application does not limit the content of the lithium salt in the electrolyte, as long as it achieves the purpose of this application.

[0046] Furthermore, this application does not impose any particular limitation on non-aqueous solvents, as long as they can achieve the purpose of this application. For example, non-aqueous solvents may include, but are not limited to, at least one of ether compounds or other organic solvents. The aforementioned ether compounds may include, but are not limited to, at least one of 1,3-dioxapentane (DOL), ethylene glycol dimethyl ether (1,2-dimethoxyethane, DME), dibutyl ether, tetraethylene glycol dimethyl ether, diethylene glycol dimethyl ether, 1,2-diethoxyethane, 1-ethoxy-1-methoxyethane, 2-methyltetrahydrofuran, or tetrahydrofuran.

[0047] This application does not impose any particular limitation on the types of other organic solvents, as long as they can achieve the purpose of this application. For example, they may include, but are not limited to, at least one of the following organic solvents: ether compounds, dimethyl sulfoxide, 1,2-dioxolane, sulfolane, methyl sulfolane, 1,3-dimethyl-2-imidazolium ketone, N-methyl-2-pyrrolidone, dimethylformamide, acetonitrile, trimethyl phosphate, triethyl phosphate, or trioctyl phosphate, or other organic solvents. The aforementioned ether compounds may include, but are not limited to, at least one of the following: ethylene glycol dimethyl ether, dibutyl ether, tetraethylene glycol dimethyl ether, diethylene glycol dimethyl ether, 1,2-dimethoxyethane, 1,2-diethoxyethane, 1-ethoxy-1-methoxyethane, 2-methyltetrahydrofuran, or tetrahydrofuran.

[0048] In one possible implementation, the first electrode diaphragm 1212 includes a first material, which may include lithium cobalt oxide, lithium manganese oxide, lithium iron phosphate, lithium manganese iron phosphate, lithium manganese phosphate, ternary materials, or Li. a1 Co x1 M1 k1 O 2、 Li a2 Ni x2 Co y2 D z2 M2 k2 At least one of O2, wherein 0.85≤a1≤1.1, 0.85≤a2≤1.1, 0.85≤x1≤1.05, 0.3≤x2≤0.98, 0≤y2≤0.5, 0≤z2≤0.5, 0≤k1≤0.15, 0≤k2≤0.15; D includes at least one of Mn and Al, M1 includes at least one of Al, Mg, Ti, Zr, Y, La, W, B, Nb and Mn, and M2 includes at least one of Al, Mg, Ti, Zr, Y, La, W, B, Nb and Mn.

[0049] In another possible implementation, the second electrode diaphragm 1222 includes a second material, which includes at least one of natural graphite, artificial graphite, carbonaceous material, silicon-carbon composite material, or silicon-oxygen composite material. In a specific example, the second material includes a silicon-based material of silicon-carbon composite material and / or silicon-oxygen composite material, wherein the silicon content in the second material is 5 wt% to 70 wt%, for example, 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 50 wt%, 60 wt%, or 65 wt%.

[0050] In one possible implementation, the material of at least one of the first current collector 1211 and the second current collector 1221 includes one or more of the following: stainless steel, aluminum, nickel, titanium, baked carbon, copper, stainless steel surface-treated with carbon, nickel, titanium or silver, aluminum-cadmium alloy, non-conductive polymer surface-treated with conductive material, conductive polymer, metal paste containing metal powder of Ni, Al, Au, Ag, Al, Pd / Ag, Cr, Ta, Cu, Ba or ITO, or carbon paste containing carbon powder of graphite, carbon black or carbon nanotubes.

[0051] For example, the conductive material includes one or more of polyacetylene, polyaniline, polypyrrole, polythiophene, polysulfide, indium tin oxide (ITO), silver, palladium, and nickel.

[0052] For example, the conductive polymer includes one or more of polyacetylene, polyaniline, polypyrrole, polythiophene, and polysulfide.

[0053] In one possible implementation, the perimeter P1 of the first cross-section is 0.25 mm to 2.5 mm, for example, 0.2 mm, 0.4 mm, 0.6 mm, 0.8 mm, 1.0 mm, 1.2 mm, 1.4, 1.6, 1.8, 2, 2.2, or 2.4 mm. In another implementation, the perimeter P2 of the second cross-section is 0.3 mm to 3.0 mm, for example, 0.5 mm, 0.8 mm, 1.0 mm, 1.2 mm, 1.5 mm, 1.8 mm, 2.0 mm, 2.4 mm, 2.6 mm, or 2.8 mm. By controlling the perimeters of the first and second cross-sections, i.e., defining the diameter of the cross-section of the first electrode 121 and the cross-section of the second electrode 122, the bending moment required is very small. Furthermore, the bending stress is uniformly distributed along the cross-section, allowing for flexible adjustment of the bending radii of the first and second electrodes 122. Simultaneously, the internal strain generated during the bending process of the first and second electrodes 121 and 122 is also minimal.

[0054] In one possible implementation, the length L1 of the first electrode 121 along the first direction is 10 mm to 800 mm, for example, 30 mm, 50 mm, 80 mm, 100 mm, 150 mm, 200 mm, 250 mm, 300 mm, 350 mm, 400 mm, 500 mm, 600 mm, or 700 mm. In another implementation, the length L2 of the second electrode 122 along the first direction is 11 mm to 801 mm, for example, 30 mm, 50 mm, 80 mm, 100 mm, 150 mm, 200 mm, 250 mm, 300 mm, 350 mm, 400 mm, 500 mm, 600 mm, or 700 mm. This results in a longer bending moment for both the first electrode 121 and the second electrode 122, making bending easier.

[0055] In one example, A satisfies: 15 mm 2 ≤A≤400 mm 2 For example, 20 mm 2 40 mm 2 60 mm 2 100 mm 2 150 mm 2 200 mm 2 250 mm 2 Or 280 mm 2 In one example, B satisfies: 30 mm 2 ≤B≤400 mm 2 For example, 40 mm 2 60 mm 2 100 mm 2 150 mm 2 200 mm 2 250 mm 2 Or 280 mm 2 wait.

[0056] For the second electrode 122 doped with silicon-based materials, sufficient surface area redundancy can reduce its actual areal capacity load, thereby alleviating the volume expansion stress during charging and discharging, and reducing particle breakage and SEI film rupture-regeneration cycle.

[0057] In one possible implementation, the first current collector 1211 includes a first core material 1211b and a first conductive element 1211c wound around the first core material 1211b. In a specific example, the first conductive element 1211c is linear, cable-like, or tubular, the first core material 1211b is tubular, and the first conductive element 1211c is spirally wound around the outer side of the first core material 1211b, with the first core material 1211b located on the inner side. By setting the first core material 1211b and the first conductive element 1211c, the flexibility of the first current collector 1211 is improved, making the first current collector 1211 easier to bend, and the stress distribution within the first current collector 1211 is more uniform after bending, without stress concentration points.

[0058] In one possible implementation, the first conductive element 1211c includes a plurality of first segments connected to each other, and the surface of the first current collector 1211 is formed with a first recess 1211a, which is formed between two first segments of adjacent first conductive elements 1211c.

[0059] In one example, such as Figure 4 As shown, multiple first segments of the first conductive element 1211c are spirally connected. These multiple first segments are formed on the outer side of the first core material 1211b. The multiple first segments are arranged along the extending direction of the first core material 1211b. Adjacent first segments form first recesses 1211a, thereby making the surface of the first current collector 1211 uneven. This provides deformation space for the bending of the first electrode 121 and releases the bending stress of the first electrode 121. At the same time, the uneven surface of the first current collector 1211 can also increase the contact area between the first current collector 1211 and the first electrode diaphragm 1212, thereby increasing the adhesion strength between the first electrode diaphragm 1212 and the first current collector 1211 and preventing local detachment of the first electrode diaphragm 1212 from the first current collector 1211 during bending.

[0060] In one example, the first conductive element 1211c covers the side of the first core material 1211b, meaning that multiple segments of the first conductive element 1211c completely wrap around and cover the outer side of the first core material 1211b, so that the outer side of the first core material 1211b does not contact the first electrode diaphragm 1212. Sufficient contact between the first electrode diaphragm 1212 and the first conductive element 1211c ensures that the energy of the first electrode diaphragm 1212 is fully utilized.

[0061] In one possible implementation, the second current collector 1221 includes a second core material 1221b and a second conductive element 1221c wound around the second core material 1221b. In one example, the second conductive element 1221c includes a plurality of second segments connected to each other, and a second recess 1221a is formed on the surface of the second current collector 1221, the second recess 1221a being formed between two second segments of adjacent second conductive elements 1221c. In one example, as... Figure 5 As shown, multiple second segments of the second conductive element 1221c are spirally connected. These multiple second segments are formed on the outer side of the second core material 1221b. The multiple second segments are arranged along the extending direction of the first core material 1211b. Adjacent second segments form second recesses 1221a, thereby making the surface of the second current collector 1221 uneven. This provides deformation space for the bending of the second electrode 122, releasing the bending stress of the second electrode 122. At the same time, the uneven surface of the second current collector 1221 can also increase the contact area between the second current collector 1221 and the second electrode diaphragm 1222, thereby increasing the adhesion strength between the second electrode diaphragm 1222 and the second current collector 1221, preventing local detachment of the second electrode diaphragm 1222 from the second current collector 1221 during bending.

[0062] refer to Figure 1 In one example, the second conductive element 1221c covers the side of the second core material 1221b, that is, multiple segments of the second conductive element 1221c completely wrap around and cover the outer side of the second core material 1221b, so that the outer side of the second core material 1221b does not contact the second electrode diaphragm 1222, and the second electrode diaphragm 1222 and the second conductive element 1221c are in full contact, ensuring that the energy of the second electrode diaphragm 1222 is fully utilized.

[0063] In one example, the second electrode 122 is a negative electrode, and the second current collector 1221 of the second electrode 122 includes a second core material 1221b and a second conductive element 1221c wound around the second core material 1221b. The second electrode 122 includes the second current collector 1221 and a second electrode diaphragm 1222 located on the second current collector 1221. The second material in the second electrode diaphragm 1222 includes silicon-carbon composite material and / or silicon-oxygen composite material, which is a silicon-based material. The silicon content in the second material is 5 wt% to 70 wt%, for example, 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 50 wt%, 60 wt%, or 65 wt%. By providing a second core material 1221b and a second conductive element 1221c wound around the second core material 1221b, the expansion stress of the silicon-doped negative electrode during the charging and discharging process can be absorbed, preventing the second electrode 122 from shedding powder due to excessive expansion stress during the charging and discharging process.

[0064] In one possible implementation, the material of the first core material 1211b and / or the material of the second core material 1221b includes one or more of polymer resins, rubber, and inorganic materials. In one example, the polymer resin includes polyethylene terephthalate (PET), polyvinyl chloride (PVC), high-density polyethylene (HDPE), epoxy resin, and polypropylene (PP). In another specific example, the inorganic material includes at least one of alumina, silica, carbon black, and graphite. In one example, the material of the first core material 1211b and / or the second core material 1221b may be, for example, in the form of wires, fibers, powders, meshes, or foams.

[0065] In another possible implementation, at least one of the first conductive element 1211c and the second conductive element 1221c is made of one or more of the following materials: stainless steel, aluminum, nickel, titanium, baked carbon, copper, stainless steel surface treated with carbon, nickel, titanium or silver, aluminum-cadmium alloy, non-conductive polymer surface treated with conductive material, or conductive polymer.

[0066] For example, the conductive material includes one or more of polyacetylene, polyaniline, polypyrrole, polythiophene, polysulfide, indium tin oxide (ITO), silver, palladium, and nickel.

[0067] For example, the conductive polymer includes one or more of polyacetylene, polyaniline, polypyrrole, polythiophene, and polysulfide.

[0068] In one possible implementation, the diameter of the cross-section of the first core material 1211b perpendicular to the first direction is d1, and the diameter of the cross-section of the first conductive element 1211c perpendicular to the first direction is d2. d1 and d2 satisfy the following: the diameter ratio is 2 ≤ d1 / d2 ≤ 100, for example, 5, 7, 10, 15, 20, 25, 30, 35, 40, 45, 50, 60, 70, 80, 90. d1 satisfies: 0.05 mm ≤ d1 ≤ 1 mm, for example, 0.1 mm, 0.3 mm, 0.5 mm, 0.7 mm, 0.9 mm. d2 satisfies: 0.01 mm ≤ d2 ≤ 0.5 mm, for example, 0.02 mm, 0.05 mm, 0.08 mm, 0.1 mm, 0.2 mm, 0.3 mm, or 0.4 mm.

[0069] By controlling the diameter of the cross-section of the first core material 1211b perpendicular to the first direction and the diameter of the cross-section of the first conductive element 1211c perpendicular to the first direction, that is, making the diameter of the cross-section of the first core material 1211b perpendicular to the first direction larger than the diameter of the cross-section of the first conductive element 1211c perpendicular to the first direction, and the ratio being between 2 and 100, the larger diameter of the first core material 1211b can provide extremely high axial tensile strength and modulus, preventing the fiber electrode from breaking when stretched or bent, while the smaller diameter of the first conductive element 1211c provides excellent radial flexibility and bendability, and can evenly distribute bending stress. Moreover, the smaller diameter of the first conductive element 1211c can reduce the impedance of the first conductive element 1211c, enabling rapid insertion and extraction of lithium ions, and improving the peak power and fast charging capability of the battery 10.

[0070] In one possible implementation, the diameter of the cross-section of the second core material 1221b perpendicular to the first direction is d3, and the diameter of the cross-section of the second conductive element 1221c perpendicular to the first direction is d4. d3 and d4 satisfy: 2 ≤ d3 / d4 ≤ 100, for example, 4, 8, 10, 15, 20, 30, 40, 50, 60, 70, 80, or 90. d3 satisfies: 0.05 mm ≤ d3 ≤ 1 mm, for example, 0.07 mm, 0.1 mm, 0.3 mm, 0.5 mm, 0.8 mm, or 0.9 mm. d4 satisfies: 0.01 mm ≤ d4 ≤ 0.5 mm, for example, 0.03 mm, 0.05 mm, 0.08 mm, 0.1 mm, 0.2 mm, 0.3 mm, or 0.4 mm. By controlling the diameter of the cross-section of the second core material 1221b perpendicular to the first direction and the diameter of the cross-section of the second conductive element 1221c perpendicular to the first direction, that is, making the diameter of the cross-section of the second core material 1221b perpendicular to the first direction larger than the diameter of the cross-section of the second conductive element 1221c perpendicular to the first direction, and the ratio being between 2 and 100, the larger diameter second core material 1221b can provide extremely high axial tensile strength and modulus, preventing the fiber electrode from breaking when stretched or bent, while the smaller diameter second conductive element 1221c provides excellent radial flexibility and bendability, and can evenly distribute bending stress. Moreover, the smaller diameter second conductive element 1221c can reduce the impedance of the second conductive element 1221c, enabling rapid insertion and extraction of lithium ions, and improving the peak power and fast charging capability of the battery 10.

[0071] In one possible implementation, along the second direction, the thickness h1 of the first electrode film 1212 and the thickness h2 of the second electrode film 1222 satisfy: 0.9 ≤ h1 / h2 ≤ 1.1, for example, 0.95, 1.05, thereby further preventing lithium plating of the second electrode 122 during the charging and discharging process.

[0072] In another possible implementation, along the first direction, the length of the first electrode 121 is L1, and the length of the second electrode 122 is L2, where L1 < L2. Preferably, 0.5 mm ≤ (L2 - L1) ≤ 10 mm, for example, 0.7 mm, 1 mm, 3 mm, 5 mm, 7 mm, or 9 mm. The second direction is perpendicular to the first direction. In a specific example, the first direction is the length direction of the battery 10, and the second direction is the thickness direction of the battery 10. By limiting the range of the length difference between the first electrode 121 and the second electrode 122, it can be ensured that the electrochemical active areas of the first electrode 121 and the second electrode 122 are different in the axial direction. This ensures that the lithium ions released at each position have enough second electrode 122 to receive them in the axial direction, avoiding local "no corresponding area" caused by entanglement. The extra part of the second electrode 122 can provide a buffer zone, and also ensures that the safe state of the second electrode 122 covering the first electrode 121 is always maintained, and the end of the first electrode 121 will not be accidentally exposed. This prevents the length of the second electrode 122 from being too large, so that the excess part does not participate in the electrochemical reaction, which would reduce the overall mass energy density and volume energy density of the battery 10 and increase the material cost.

[0073] refer to Figure 9 In one possible implementation, at least one of the first electrode diaphragm 1212 and the second electrode diaphragm 1222 is provided with at least one groove 1214, which is formed, for example, by laser cleaning or machine scraping. By forming the groove 1214 on the electrode diaphragm, the wetting efficiency of the electrolyte can be improved, and the tighter contact with the insulating layer 123 or with the electrode diaphragm of the other polarity can also be increased.

[0074] In a further embodiment, the depth h3 of the groove 1214 is 2 μm to 50 μm, for example, 5 μm, 9 μm, 13 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, or 45 μm. This prevents excessive depth from causing powder shedding from the electrode film.

[0075] In one example, the spacing L3 between adjacent grooves 1214 is ≥ 0.05 mm, for example, 0.07 mm, 0.08 mm, 0.1 mm, 0.2 mm, 0.3 mm, or 0.5 mm. In another embodiment, the angle α between the groove 1214 and the first direction is 0° to 60°, for example, 5°, 10°, 20°, 30°, 40°, or 50°. In a specific example, the extending direction of the groove 1214 and the length direction of the first electrode 121 form an angle of 0° to 60°, for example, 5°, 10°, 20°, 30°, 40°, or 50°, that is, the groove 1214 extends obliquely.

[0076] In another embodiment, the grooves 1214 are arranged in an array along the periphery of the first electrode diaphragm 1212 and / or the second electrode diaphragm 1222, or the grooves 1214 are spirally arranged around the axis of the first electrode 121 or the second electrode 122. By spirally arranging the grooves 1214 in the same direction as the alternating spirals of the first electrode 121 and the second electrode 122, the grooves 1214 can also alleviate the torsional stress on the electrodes during spiral winding.

[0077] refer to Figure 1 , Figure 6 and Figure 7 In one possible implementation, the insulating layer 123 surrounds the surface of the first electrode diaphragm 1212 facing away from the first current collector 1211. In one example, the first insulating layer 123 includes a first adhesive layer 124, which includes first particles. The composition of the first particles includes a first polymer, which includes at least one of an ester-containing polymer or a fluoropolymer. By providing the first adhesive layer 124 containing the first polymer, the insulating layer 123 can bond the first electrode 121 and the second electrode 122 while achieving insulation between the first electrode 121 and the second electrode, and enabling normal lithium-ion transport and deintercalation between the first electrode 121 and the second electrode 122. The insulating layer 123 also prevents the first electrode 121 and the second electrode 122 from sliding relative to each other along a first direction.

[0078] In one example, the monomers forming the fluoropolymer include one or more of vinylidene fluoride, tetrafluoroethylene, hexafluoroethylene, and hexafluoropropylene. In another example, the fluoropolymer includes one or more of polyvinylidene fluoride, polytetrafluoroethylene, polyvinylidene fluoride, polyhexafluoropropylene, fluoroethylene-hexafluoropropylene copolymer, vinylidene fluoride-hexafluoropropylene copolymer, and tetrafluoroethylene-hexafluoropropylene copolymer.

[0079] In one example, the monomers forming the first polymer include one or more of methyl methacrylate, butyl acrylate, n-propyl acrylate, octyl acrylate, ethyl methacrylate, isooctyl acrylate, octadecyl acrylate, ethyl acrylate, cyclohexyl acrylate, and 2-hydroxyethyl acrylate; and / or, the first polymer includes one or more of polymethyl methacrylate, polyethylhexyl acrylate, polybutyl acrylate, acrylate-acrylonitrile copolymer, acrylate-ethylene copolymer, acrylate-acrylonitrile-ethylene copolymer, styrene-acrylate monomer-acrylonitrile copolymer, ethylhexyl acrylate-methyl methacrylate copolymer, butyl acrylate-methyl methacrylate copolymer, methyl acrylate-N,N-dimethylacrylamide copolymer, ethyl acrylate-2-(diethylamino)ethyl acrylate copolymer, ethyl acrylate-N,N-diethylacrylamide copolymer, and ethyl acrylate-2-(diethylamino)ethyl acrylate.

[0080] refer to Figure 6 In one possible implementation, the insulating layer 123 includes a first sub-insulating layer 1231 and a second sub-insulating layer 1232. The first sub-insulating layer 1231 is disposed on the surface of the first electrode diaphragm 1212 facing away from the first current collector 1211, and the second sub-insulating layer 1232 is disposed on the surface of the second electrode diaphragm 1222 facing away from the second current collector 1221. The first sub-insulating layer 1231 and the second sub-insulating layer respectively encapsulate the first electrode 121 and the second electrode 122, further preventing the risk of relative slippage between the first electrode 121 and the second electrode 122 along the first direction that may occur when the first electrode 121 and the second electrode 122 expand during bending operations or charging and discharging processes, thus avoiding the risk of short circuit between them.

[0081] In one example, at least one of the first sub-insulating layer 1231 and the second sub-insulating layer 1232 includes a second adhesive layer 125, the second adhesive layer 125 including second particles, the second particles being composed of a second polymer, the second polymer including at least one of an ester-containing polymer or a fluoropolymer.

[0082] For ease of description, the height direction of the battery 10 (the direction parallel to the extension direction of the tab) is defined as the first direction X, the thickness direction is defined as the third direction Z, and the direction perpendicular to the first direction X and the third direction Z is defined as the second direction.

[0083] It is understood that, without conflict, the above embodiments can be combined with each other to form new embodiments.

[0084] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications or equivalent substitutions made within the spirit and principles of this application should be included within the protection scope of this application.

[0085] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0086] Furthermore, 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. Thus, 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.

[0087] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a 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 of 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.

[0088] 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.

[0089] In this application, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. 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.

[0090] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

[0091] The present application is described in detail below with reference to specific embodiments, which are used to understand rather than limit the present application.

[0092] Unless otherwise specified, all materials and reagents used in the following examples are commercially available. Unless otherwise specified, the processing procedures and techniques involved are conventional technical methods.

[0093] Example 1 Negative electrode preparation: The negative electrode active material (i.e., negative electrode active material), sodium carboxymethyl cellulose, styrene-butadiene rubber, and conductive carbon black are dispersed in deionized water (or water) at a mass percentage of 93:2.5:1.5:3 and mixed evenly to obtain a slurry. The prepared negative electrode slurry is uniformly coated onto the negative electrode current collector, dried at 100°C, compacted, and slit to obtain the negative electrode. The negative electrode active material is a graphite and silicon-carbon composite material. The silicon content in the negative electrode active material is 19%, and the silicon content in the silicon-carbon composite material is 45%. The silicon content is controlled by controlling the content of the silicon-carbon composite material in the negative electrode active material. The negative electrode current collector includes a core material formed of polymer fibers (e.g., polyimide, polyethylene, polyester fiber) and copper wires wound around the core material, with winding gaps (recesses) between the copper wires.

[0094] Positive electrode preparation: The positive electrode active material lithium nickel cobalt manganese oxide (NCM), the binder polyvinylidene fluoride, and the conductive agent carbon black are mixed in a mass percentage ratio of 97.2:1.8:1. An appropriate amount of N-methylpyrrolidone is added as a solvent, and the mixture is stirred until homogeneous, forming a uniformly dispersed electrode slurry with a solid content of 65 wt%. The prepared positive electrode slurry is uniformly coated onto the positive electrode current collector, dried at 100°C, compacted, and slit to form the positive electrode. The positive electrode current collector comprises a core material formed of polymer fibers (e.g., polyimide, polyethylene, polyester fibers) and aluminum wires wound around the core material, with winding gaps (recesses) between the aluminum wires.

[0095] Preparation and coating of insulating layer 123: Polyethylene oxide (PEO) (weight-average molecular weight (Mw) = 4,000,000 g / mol) was dissolved in acetonitrile (AN) as a solvent to prepare a 4 wt% PEO solution, and lithium bis(fluorosulfonyl)imide (LiFSI, (FSO2)2NLi) as a lithium salt was added to make the [EO] / [Li+] molar ratio = 20 / 1. The resulting mixture was then stirred overnight at 70 °C to allow the PEO and lithium salt to dissolve sufficiently in the PEO solution.

[0096] To obtain the polymer crosslinking structure, polyethylene glycol diacrylate (PEGDA) with two functional groups (weight-average molecular weight (Mw) = 575) and benzoyl peroxide (BPO) as an initiator were introduced into a lithium salt solution and stirred thoroughly to prepare a composition for use in an insulating coating. Here, the amount of PEGDA was 20 parts by weight based on 100 parts by weight of PEO, and the amount of BPO was 1 part by weight based on 100 parts by weight of PEGDA.

[0097] The prepared composition for forming the insulating coating is applied to the negative electrode active material layer and the positive electrode active material layer, respectively. The coating is performed by extrusion coating.

[0098] The composition for forming the insulating coating is introduced into the hopper of an extruder. The extruder barrel is maintained at a temperature of 50°C, and the screw rotation speed is maintained at 60 to 70 rpm. The negative electrode is fed to the extruder die at a rate of 3 m / min so that the outer surface of the negative electrode active material layer can be used for extrusion coating of the composition for forming the insulating coating. Subsequently, the coated composition is dried in a dryer chamber at 100°C and then vacuum dried at the same temperature for 12 hours to obtain a negative electrode with a first insulating coating.

[0099] In addition to using a positive electrode, a positive electrode with a second insulating coating formed on its outer surface is obtained using the same method as described above for manufacturing a negative electrode.

[0100] Then, while bringing the prepared negative and positive electrodes into contact with each other, they are spirally wound along their length to form a linear electrode assembly (cell 12) containing negative and positive electrodes alternately arranged on the same circumferential surface. The resulting cell 12 is then enclosed in a casing 11 made of polyvinyl chloride (PVC) resin coated with metallic nickel to obtain a battery 10.

[0101] Then, the battery cell 12 is housed in the casing 11 and manufactured into a battery 10 through steps such as encapsulation, electrolyte injection, formation, secondary sealing, and capacity testing. Here, the electrolyte is a commercially available electrolyte.

[0102] The surface area of ​​the positive electrode is A = 301 mm. 2 The surface area of ​​the negative electrode is B = 373 mm. 2 A / B = 0.8. The perimeter of the cross-section of the first electrode 121 is P1 = 0.43 mm, and the length of the first electrode 121 is L1 = 700 mm. The perimeter of the cross-section of the second electrode 122 is P2 = 0.53 mm, and the length of the second electrode 122 is L2 = 703 mm. (L2 - L1) = 3 mm. The diameter of the cross-section perpendicular to the first direction of the first core material 1211b is d1 = 0.07 mm, and the diameter of the cross-section perpendicular to the first direction of the first conductive element 1211c is d2 = 0.035 mm. d1 / d2 = 2. The diameter of the cross-section perpendicular to the first direction of the second core material 1221b is d3 = 0.05 mm, and the diameter of the cross-section perpendicular to the first direction of the second conductive element 1221c is d4 = 0.025 mm. d3 / d4 = 2. Grooves 1214 are respectively provided on the first electrode diaphragm 1212 and the second electrode diaphragm 1222. The depth of the groove 1214 is h3 = 10 μm, and the distance between adjacent grooves 1214 is L3 = 0.07 mm. The angle α between the groove 1214 and the first direction is 45°. h1 / h2 = 1.

[0103] Example 2 This embodiment is based on Embodiment 1, except that the surface area of ​​the positive electrode is A = 200 mm². 2A / B = 0.53. L1 = 791 mm, L2 = 801 mm. (L2-L1) = 10 mm. P1 = 0.25 mm, P2 = 0.46 mm. The diameter of the cross-section perpendicular to the first direction of the first core material 1211b is d1 = 0.05 mm, and the diameter of the cross-section perpendicular to the first direction of the first conductive element 1211c is d2 = 0.012 mm. d1 / d2 = 4.12. The diameter of the cross-section perpendicular to the first direction of the second core material 1221b is d3 = 0.05 mm, and the diameter of the cross-section perpendicular to the first direction of the second conductive element 1221c is d4 = 0.012 mm. d3 / d4 = 4.12. Grooves 1214 are respectively provided on the first electrode diaphragm 1212 and the second electrode diaphragm 1222. The depth of the groove 1214 is h3 = 2 μm, and the distance between adjacent grooves 1214 is L3 = 0.5 mm. The angle α between the groove 1214 and the first direction is 60°. h1 / h2=0.9.

[0104] Example 3 This embodiment is based on Embodiment 1, except that the surface area of ​​the positive electrode is A = 353 mm². 2 B=299 mm 2 A / B = 1.18. L1 = 359.5 mm, L2 = 360 mm. (L2 - L1) = 0.5 mm. P1 = 1 mm, P2 = 0.85 mm. The diameter of the cross-section perpendicular to the first direction of the first core material 1211b is d1 = 0.1 mm, and the diameter of the cross-section perpendicular to the first direction of the first conductive element 1211c is d2 = 0.01 mm. d1 / d2 = 1.96. The diameter of the cross-section perpendicular to the first direction of the second core material 1221b is d3 = 0.1 mm, and the diameter of the cross-section perpendicular to the first direction of the second conductive element 1221c is d4 = 0.02 mm. d3 / d4 = 5. Grooves 1214 are respectively provided on the first electrode diaphragm 1212 and the second electrode diaphragm 1222. The depth of the groove 1214 is h3 = 49 μm, and the distance between adjacent grooves 1214 is L3 = 0.9 mm. The angle α between the groove 1214 and the first direction is 0°. h1 / h2=1.1.

[0105] Example 4 This embodiment is based on Embodiment 1, except that the surface area of ​​the positive electrode is A = 25 mm. 2 B=33 mm 2A / B = 0.76. L1 = 10 mm, L2 = 11 mm. (L2 - L1) = 1 mm. P1 = 2.5 mm, P2 = 3 mm. The diameter of the cross-section perpendicular to the first direction of the first core material 1211b is d1 = 1 mm, and the diameter of the cross-section perpendicular to the first direction of the first conductive element 1211c is d2 = 0.01 mm. d1 / d2 = 100. The diameter of the cross-section perpendicular to the first direction of the second core material 1221b is d3 = 1 mm, and the diameter of the cross-section perpendicular to the first direction of the second conductive element 1221c is d4 = 0.01 mm. d3 / d4 = 100.

[0106] Example 5 This embodiment is performed with reference to Embodiment 1, except that A = 302 mm. 2 A / B = 0.81, the length of the positive electrode L1 = 702.7 mm, (L2-L1) = 0.3 mm.

[0107] Example 6 This embodiment is performed with reference to Embodiment 1, except that B = 377 mm. 2 The length of the negative electrode is L2 = 711 mm, and (L2 - L1) = 11 mm.

[0108] Example 7 This embodiment is based on Embodiment 1, except that d2 = 0.04 mm and d1 / d2 = 1.75.

[0109] Example 8 This embodiment is based on Embodiment 1, except that d2 = 0.003 mm and d1 / d2 = 102.

[0110] Example 9 This embodiment is based on Embodiment 1, except that d4 = 0.03 mm and d1 / d2 = 1.67.

[0111] Example 10 This embodiment is based on Embodiment 1, except that d4 = 0.00048 mm and d1 / d2 = 104.

[0112] Example 11 This embodiment is based on Embodiment 1, except that the groove 1214 is not provided.

[0113] Comparative Example 1 This embodiment is performed with reference to Embodiment 1, except that B = 734 mm. 2 A / B = 0.41. P2 = 1.04.

[0114] Comparative Example 2 This embodiment is based on Embodiment 1, except that B = 223 mm. 2 A / B = 1.35. P1 = 0.32.

[0115] Material property testing 1. Cyclic performance pass rate conditions and methods (including sample quantity): 1) Sample grouping: The number of samples for each embodiment is 20.

[0116] 2) Test methods: a. Cyclic capacity retention test method: Conduct the experiment at 25℃±+5℃ using the following steps: a. Charge at a constant current rate of 2C, cut off at a rate of 0.05C, and then discharge at a constant current rate of 4C, with a voltage range of 2.0V to 4.3V. This constitutes one charge-discharge cycle.

[0117] b. Record the discharge capacity Q1 in week 1 and the discharge capacity Q1000 in week 1000. Calculate the cycle capacity retention rate of the battery after 10 cycles (Q1000 / Q1×100%).

[0118] Experimental results: If the cycle capacity retention rate of cell 12 is greater than 80% after 1000T cycles, it is considered to have passed. For example, 10P / 20P means that 10 out of 20 cells 10 have passed the test, that is, among the 20 cells 10 tested, 10 cells 10 have a cycle capacity retention rate greater than 80%.

[0119] 2. Thickness expansion rate test method: Ten samples were used for each embodiment. The lithium-ion batteries were placed in a 45°C environment and allowed to stand for 5 minutes. Then, they were charged and discharged as follows: discharged at a constant current of 0.5C to 3V, allowed to stand for 5 minutes, charged at a constant current of 1.1C to 4.25V, charged at a constant current of 0.7C to 4.51V, charged at a constant voltage to 0.05C, allowed to stand for 5 minutes, and discharged at a constant current of 0.5C to 3V. This constituted one cycle, and the cycle was repeated 100 times. The initial thickness H0 of the lithium-ion battery was recorded. After 100 cycles, the thickness H3 of the secondary battery was measured. The expansion rate was calculated as (H3 - H0) / H0 × 100%. The maximum and minimum expansion rates were removed from each sample group, and the average expansion rate was calculated.

[0120] 3. Lithium plating performance test: The lithium-ion batteries in the examples and comparative examples were placed in a constant temperature chamber at 10°C. After 60 minutes, they were charged at a constant current of 2C to 4.5V, then charged at a constant voltage of 4.5V to a current of 0.025C. After resting for 5 minutes, they were discharged at a constant current of 0.5C to 3.0V. This constitutes one cycle. After 100 cycles of the above charge-discharge process, the batteries were charged at a constant current of 2C to 4.5V, then charged at a constant voltage of 4.5V to a current of 0.025C. After resting for 5 minutes, the lithium-ion batteries were disassembled, and the outer negative electrode of the electrode assembly was removed. The lithium plating state on the surface of the outer negative electrode was observed. The non-lithium-plated area on the surface of the outer negative electrode was golden yellow, while the lithium-plated area was grayish-white.

[0121] The criteria for judging the degree of lithium plating in lithium-ion batteries are as follows: 0% lithium plating area is considered no lithium plating, i.e., the degree of lithium plating is zero; lithium plating area greater than 0 and less than or equal to 2% is considered mild lithium plating; lithium plating area greater than 2% and less than or equal to 20% is considered moderate lithium plating; and lithium plating area greater than 20% and less than or equal to 100% is considered severe lithium plating. The percentage of lithium plating area is calculated based on the total area of ​​the negative electrode material layer of the outer negative electrode sheet.

[0122] 4. Electrode damage rate test method: The lithium-ion batteries from the 10 examples and comparative examples were tested. Each lithium-ion battery was placed in a 55°C environment and left to stand for 30 minutes before being charged and discharged according to the following steps: Charge at a constant current of 2.5C to 4.2V, then charge at a constant voltage of 0.5C. Then charge at a constant current of 0.5C to 4.45V, then charge at a constant current of 0.02C. Let stand for 5 minutes, then discharge at a constant current of 1C to 3V, and let stand for 5 minutes. This constitutes one cycle. Repeat the above cycle steps 1000 times. After the cycle test, the lithium-ion batteries were disassembled, and the positive and negative electrodes were visually inspected for damage. The number of batteries with torn or broken casings, positive electrodes, and negative electrodes was recorded. The electrode damage rate during the cycle test = (number of damaged batteries / 10) × 100%.

[0123] Table 1 shows the test results.

[0124] Table 1 The data above shows that when the A / B ratio is too high, it affects the N / P ratio of battery 10, making it prone to lithium plating on the negative electrode, which leads to poor cycle performance of battery 10. When the A / B ratio is too low, the cycle performance may be affected by the expansion and shedding of powder on the negative electrode.

[0125] When (L2-L1) is higher than the upper limit, it will affect the energy density of battery 10 and thus affect its cycle performance; when (L2-L1) is lower than the lower limit, lithium plating may affect the cycle performance of battery 10.

[0126] When d1 / d2 is higher than the upper limit, the first conductive element 1211c may become weak and break, affecting the cycle performance; when d1 / d2 is lower than the lower limit, the first core material 1211b may become weak and break, affecting the cycle performance of the battery 10.

[0127] When d3 / d4 is higher than the upper limit, the second conductive component 1221c may become weak and break, affecting the cycle performance; when d3 / d4 is lower than the lower limit, the second core material 1221b may become weak and break, affecting the cycle performance of the battery 10.

[0128] Without the groove 1214, the wetting ability of the electrolyte is limited, which affects the cycle performance of the battery 10.

Claims

1. A battery, characterized in that, include: A linear first electrode and a linear second electrode are provided, with an insulating layer disposed between the first electrode and the second electrode. The first electrode is the positive electrode and the second electrode is the negative electrode. The first electrode includes a first current collector extending along a first direction and a first electrode film formed on the outside of the first current collector; The second electrode includes a second current collector extending along the first direction and a second electrode diaphragm formed on the outside of the second current collector; The first electrode and the second electrode are arranged in a wound manner; The first electrode has a first cross-section perpendicular to the first direction, and the second electrode has a second cross-section perpendicular to the first direction. The product of the perimeter of the first cross-section and the length of the first electrode is A, and the product of the perimeter of the second cross-section and the length of the first electrode is B. A and B satisfy 0.5 ≤ A / B ≤ 1.

2.

2. The battery according to claim 1, characterized in that, The perimeter P1 of the first cross-section is 0.25 mm to 2.5 mm. And / or, the perimeter P2 of the second cross section is 0.3 mm to 3.0 mm. And / or, the length L1 of the first electrode along the first direction is 10 mm to 800 mm. And / or, the length L2 of the second electrode along the first direction is 11 mm to 801 mm; And / or, A satisfies: 15 mm 2 ≤A≤400 mm 2 ; And / or, B satisfies: 30 mm 2 ≤B≤400 mm 2 .

3. The battery according to claim 1, characterized in that, The first current collector includes a first core material and a first conductive element wound around the first core material. Further, the first conductive element includes a plurality of interconnected first segments. A first recess is formed on the surface of the first current collector, and the first recess is formed between two adjacent first segments of the first conductive element. And / or, the first conductive element covers the side of the first core material; And / or, the second current collector includes a second core material and a second conductive element wound around the second core material; further, the second conductive element includes a plurality of second segments connected to each other; a second recess is formed on the surface of the second current collector, the second recess being formed between two adjacent second segments of the second conductive element. And / or, the second conductive element covers the side of the second core material.

4. The battery according to claim 3, characterized in that, The diameter of the cross-section of the first core material perpendicular to the first direction is d1, and the diameter of the cross-section of the first conductive element perpendicular to the first direction is d2. d1 and d2 satisfy the following: the diameter ratio is 2 ≤ d1 / d2 ≤ 100, where d1 satisfies: 0.05 mm ≤ d1 ≤ 1 mm, and / or d2 satisfies: 0.01 mm ≤ d2 ≤ 0.5 mm; and / or The diameter of the cross section of the second core material perpendicular to the first direction is d3, and the diameter of the cross section of the second conductive element perpendicular to the first direction is d4. d3 and d4 satisfy: 2≤d3 / d4≤100, where d3 satisfies: 0.05 mm≤d3≤1 mm, and / or d4 satisfies: 0.01 mm≤d4≤0.5 mm.

5. The battery according to claim 3, characterized in that, The material of the first core material and / or the material of the second core material includes one or more of polymer resin, rubber, and inorganic materials; further, The polymer resin includes polyethylene terephthalate (PET), polyvinyl chloride (PVC), high-density polyethylene (HDPE), epoxy resin, and polypropylene (PP), and / or The inorganic material includes at least one of alumina, silicon dioxide, carbon black, and graphite.

6. The battery according to claim 3, characterized in that, The material of at least one of the first conductive element and the second conductive element includes one or more of the following: stainless steel, aluminum, nickel, titanium, baked carbon, copper, stainless steel surface-treated with carbon, nickel, titanium, or silver, aluminum-cadmium alloy, non-conductive polymer surface-treated with conductive material, or conductive polymer; further, The conductive material includes one or more of polyacetylene, polyaniline, polypyrrole, polythiophene, polysulfide, indium tin oxide (ITO), silver, palladium, and nickel, and / or The conductive polymer includes one or more of polyacetylene, polyaniline, polypyrrole, polythiophene, and polysulfide.

7. The battery according to claim 1, characterized in that, Along the second direction, the thickness h1 of the first electrode film and the thickness h2 of the second electrode film satisfy: 0.9 ≤ h1 / h2 ≤ 1.1; and / or Along the first direction, the length of the first electrode is L1, and the length of the second electrode is L2, where L1 < L2, preferably. 0.5 mm ≤ (L2-L1) ≤ 10 mm, where The second direction is perpendicular to the first direction; and / or The material of at least one of the first current collector and the second current collector includes one or more of the following: stainless steel, aluminum, nickel, titanium, baked carbon, copper, stainless steel surface-treated with carbon, nickel, titanium, or silver, aluminum-cadmium alloy, non-conductive polymer surface-treated with conductive material, or conductive polymer; further, The conductive material includes one or more of polyacetylene, polyaniline, polypyrrole, polythiophene, polysulfide, indium tin oxide (ITO), silver, palladium, and nickel, and / or The conductive polymer includes one or more of polyacetylene, polyaniline, polypyrrole, polythiophene, and polysulfide.

8. The battery according to any one of claims 1 to 7, characterized in that, At least one of the first electrode film and the second electrode film is provided with at least one groove. Preferably, the depth h3 of the groove is 2 μm to 50 μm, and / or the spacing L3 between adjacent grooves is ≥0.05 mm, and / or The angle α between the groove and the first direction is 0° to 60°; and / or, The grooves are arranged in an array along the periphery of the first electrode film and / or the second electrode film, or the grooves are spirally arranged around the axis of the first electrode or the second electrode.

9. The battery according to any one of claims 1 to 7, characterized in that, The second electrode film comprises a second material, which includes at least one of natural graphite, artificial graphite, carbonaceous materials, silicon-carbon composite materials, or silicon-oxygen composite materials; and / or, The first electrode film includes a first material, which includes lithium cobalt oxide, lithium manganese oxide, lithium iron phosphate, lithium manganese iron phosphate, lithium manganese phosphate, ternary materials, and Li. a1 Co x1 M1 k1 O 2、 Li a2 Ni x2 Co y2 D z2 M2 k2 At least one of O2, wherein 0.85≤a1≤1.1, 0.85≤a2≤1.1, 0.85≤x1≤1.05, 0.3≤x2≤0.98, 0≤y2≤0.5, 0≤z2≤0.5, 0≤k1≤0.15, 0≤k2≤0.15; D includes at least one of Mn and Al. M1 includes at least one of Al, Mg, Ti, Zr, Y, La, W, B, Nb, and Mn. M2 includes at least one of Al, Mg, Ti, Zr, Y, La, W, B, Nb, and Mn.

10. The battery according to any one of claims 1 to 7, characterized in that, The insulating layer is disposed around the surface of the first electrode diaphragm opposite to the first current collector; or The insulating layer includes a first sub-insulating layer and a second sub-insulating layer. The first sub-insulating layer is disposed on the surface of the first electrode diaphragm opposite to the first current collector, and the second sub-insulating layer is disposed on the surface of the second electrode diaphragm opposite to the second current collector.

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