Battery cell, battery, and electric device

Abstract

A battery cell, a battery, and an electrical device. The battery cell (40) includes: an electrode assembly (10) comprising a plurality of electrode plates (10a, 10b) and a separator (10c) disposed between adjacent electrode plates (10a, 10b) of opposite polarity among the plurality of electrode plates (10a, 10b), wherein the plurality of electrode plates (10a, 10b) and the separator (10c) are wound along a winding direction (wd) to form a winding structure (100), wherein at least one of the plurality of electrode plates (10a, 10b) includes a current collector substrate (11) and a plurality of tabs (13), the plurality of tabs (13) being wound along the current collector substrate (11) along the winding direction (wd) to form a winding structure (100), wherein at least one of the plurality of electrode plates (10a, 10b) includes a current collector substrate (11) and a plurality of tabs (13), the plurality of tabs (13) being wound with respect to the current collector substrate (11) along the winding direction (wd) to form a winding structure (100). The plurality of tabs (13) are connected to at least one side extending in the winding direction (wd) and spaced apart along the winding direction (wd). At least a portion of the plurality of tabs (13) are bent toward the winding axis (CL) of the winding structure (100) and form a tab stack structure (130) at the end of the winding structure (100); a housing (4A) having a chamber for accommodating the electrode assembly (10); electrode terminals (42) disposed on the wall of the housing (4A); and conductive elements (21, 22) welded to the tab stack structure (130) and electrically connected to the electrode terminals (42).

Description

Technical Field

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

[0002] Secondary batteries, especially lithium-ion batteries, have advantages such as high voltage, high specific energy, long cycle life, being environmentally friendly and pollution-free, having a wide operating temperature range, and low self-discharge. They are widely used in portable electronic devices and power equipment for large new energy electric vehicles, and are of great significance in solving environmental pollution and the energy crisis. With the widespread use of lithium-ion batteries, battery safety has become a major concern for users. Summary of the Invention

[0003] In one aspect of this disclosure, a battery cell is provided, comprising:

[0004] An electrode assembly includes a plurality of electrodes and a spacer disposed between adjacent electrodes of opposite polarity among the plurality of electrodes. The plurality of electrodes and the spacer are wound along a winding direction to form a wound structure. At least one of the plurality of electrodes includes a current collector substrate and a plurality of tabs. The plurality of tabs are connected to at least one side of the current collector substrate extending along the winding direction and are spaced apart along the winding direction. At least a portion of the plurality of tabs is bent toward a direction close to the winding axis of the wound structure and forms a tab stack structure at the end of the wound structure.

[0005] The housing has a chamber for accommodating the electrode assembly;

[0006] Electrode terminals are disposed on the wall of the housing; and

[0007] The conductive element is welded to the electrode stack structure and electrically connected to the electrode terminals.

[0008] The conductive components are electrically connected to the electrode terminals located on the outer casing wall, and are welded to multiple tabs stacked at the end of the winding structure of the electrode assembly. The stacked multi-layer tab structure has a higher thickness, making it less likely to be welded through when welding to the conductive components. This avoids the risk of short circuits caused by burning the separator or electrode sheet in the electrode assembly during welding. As a result, the welding quality of the welding area is improved, the risk of short circuits in individual battery cells is reduced, and the safety of use is enhanced.

[0009] In some embodiments, the tab stack structure includes a first tab stack region and a second tab stack region arranged from the outside to the inside along a direction close to the winding axis. The number of tab stack layers in the first tab stack region increases along a direction close to the winding axis, and the number of tab stack layers in the second tab stack region is equal along a direction close to the winding axis. At least a portion of the welding area of ​​the conductive element and the tab stack structure is located in the second tab stack region.

[0010] The number of tab stack layers in the second tab stack region is equal along the direction close to the winding shaft. Therefore, when the conductive element is welded to the tab stack structure formed at the end of the winding structure, the second tab stack region has more tab stack layers and a higher stack thickness compared to other tab stack regions. As a result, it is not easy to be welded through when welding with the conductive element, thereby improving the welding quality of the welding area and reducing the risk of short circuit caused by the diaphragm or electrode being burned during welding.

[0011] In some embodiments, the welding area includes a first portion located in the second tab stack region and a second portion located in the first tab stack region.

[0012] By welding the second tab stack region and the first tab stack region to the conductive component through the first and second parts of the welding region, respectively, the overall size of the welding region can be increased, thereby improving the welding strength and reducing the resistance of the welding region, thus reducing the risk of overcurrent.

[0013] In some embodiments, the tab stack structure further includes a third tab stack region located on the side of the second tab stack region adjacent to the winding shaft, and the welding region further includes a third portion located in the third tab stack region.

[0014] By welding the third tab stack area to the conductive component, the overall size of the welding area can be increased, thereby improving the welding strength and reducing the resistance of the welding area, thus reducing the risk of overcurrent.

[0015] In some embodiments, the ratio S1 / S of the area S1 of the first portion to the area S of the welding region satisfies: S1 / S≥70%.

[0016] By ensuring that the ratio S1 / S is greater than or equal to 70%, the welding quality of the welding area can be improved, and the risk of electrode tab burn-through or incomplete welding can be reduced.

[0017] In some embodiments, the ratio S1 / S of the area S1 of the first portion to the area S of the welded region satisfies: S1 / S≥90%.

[0018] By further limiting the ratio S1 / S to greater than or equal to 90%, the welding quality of the welding area can be further improved, effectively reducing the risk of electrode tab burn-through or incomplete welding.

[0019] In some embodiments, the winding structure is a cylindrical winding structure, and the ratio L1 / L of the maximum radial length L1 of the first portion in the radial direction of the cylindrical winding structure to the maximum radial length L of the welding area in the radial direction of the cylindrical winding structure satisfies: L1 / L≥70%.

[0020] By ensuring that the ratio L1 / L is greater than or equal to 70%, the welding quality of the welding area can be improved, and the risk of electrode tab burn-through or incomplete welding can be reduced.

[0021] In some embodiments, the ratio L1 / L of the maximum radial length L1 of the first portion in the radial direction of the cylindrical winding structure to the maximum radial length L of the welded area in the radial direction of the cylindrical winding structure satisfies: L1 / L≥90%.

[0022] By further limiting the ratio L1 / L to greater than or equal to 90%, the welding quality of the welding area can be further improved, effectively reducing the risk of electrode tab burn-through or incomplete welding.

[0023] In some embodiments, the minimum distance d between the current collector substrate at the winding start end in the winding direction and the second electrode tab satisfies: d≤1200mm;

[0024] The second tab is defined as the tab among the plurality of tabs that is welded to the conductive element and is closest to the winding start end.

[0025] By making the minimum distance d less than or equal to 1200mm, the range of electrodes that can be directly connected to conductive parts through the welding area can be increased, reducing the risk of overcurrent in the second electrode and thus minimizing the risk of electrode overheating affecting the performance of chemical substances in the electrode assembly.

[0026] In some embodiments, the minimum distance d satisfies: d≤800mm.

[0027] By further limiting the minimum distance d to less than or equal to 800 mm, the range of electrodes directly connected to conductive components through the welding area can be increased to a greater extent, further reducing the risk of overcurrent in the first electrode, thereby more effectively preventing the electrode from overheating and affecting the performance of chemical substances in the electrode assembly.

[0028] In some embodiments, in the extending direction of the winding shaft, the maximum value Hmax of the depth H of the welding area of ​​the conductive element and the tab stack structure and the thickness t of the conductive element satisfy: 1.5*t≤Hmax≤1.9*t.

[0029] By setting a specific range for the ratio of the maximum depth Hmax of the welding area to the thickness t of the conductive component, the risk of electrode burn-through and incomplete soldering can be minimized.

[0030] In some embodiments, in the extending direction of the winding shaft, the maximum value Hmax of the depth H of the welding area and the thickness t of the conductive element satisfy: 1.6*t≤Hmax≤1.8*t.

[0031] By further limiting the selectable range of the ratio of the maximum depth Hmax of the welding area to the thickness t of the conductive part, the risk of electrode burn-through and incomplete soldering can be effectively reduced.

[0032] In some embodiments, in the extending direction of the winding shaft, the minimum value Hmin of the welding area of ​​the conductive element and the tab stack structure and the thickness t of the conductive element satisfy: 1.1*t≤Hmin≤1.5*t.

[0033] By setting a specific range for the ratio of the minimum depth Hmin of the welding area to the thickness t of the conductive component, the risk of electrode burn-through and incomplete soldering can be minimized.

[0034] In some embodiments, in the extending direction of the winding shaft, the minimum value Hmin of the depth H of the welding area and the thickness t of the conductive element satisfy: 1.2*t≤Hmin≤1.4*t.

[0035] By further limiting the selectable range of the ratio of the minimum depth Hmin of the welding area to the thickness t of the conductive part, the risk of electrode burn-through and incomplete soldering can be effectively reduced.

[0036] In some embodiments, in the extension direction of the winding shaft, the difference between the maximum value Hmax and the minimum value Hmin of the welding area of ​​the conductive element and the tab stack structure (Hmax-Hmin) and the thickness t of the conductive element satisfy: 0.2*t≤(Hmax-Hmin)≤0.8*t.

[0037] By limiting the ratio of the difference (Hmax-Hmin) to the thickness t of the conductive element to a specific range, the risk of localized burn-through or incomplete soldering of the electrode tab can be reduced.

[0038] In some embodiments, in the extension direction of the winding shaft, the difference between the maximum value Hmax and the minimum value Hmin of the depth H of the welding area (Hmax-Hmin) and the thickness t of the conductive element satisfy: 0.3*t≤(Hmax-Hmin)≤0.6*t.

[0039] By further limiting the selectable range of the ratio of the difference (Hmax-Hmin) to the thickness t, the risk of localized burn-through or incomplete soldering of the electrode tab can be further reduced.

[0040] In some embodiments, in the winding direction, the top spacing e of adjacent tabs among the plurality of tabs satisfies: e≤0.5mm.

[0041] By making the top spacing e of adjacent tabs less than or equal to 0.5mm, the degree of tab stacking can be increased, thereby obtaining a greater tab stack thickness and reducing the risk of tab burn-through.

[0042] In some embodiments, in the winding direction, the top spacing e of adjacent tabs among the plurality of tabs satisfies: e≤0.2mm.

[0043] By further limiting the top spacing e of the tabs to less than or equal to 0.2 mm, the thickness of the tab stack can be effectively increased, further reducing the risk of tab burn-through.

[0044] In some embodiments, the welding area of ​​the conductive element and the tab stack structure includes a first portion located in the second tab stack area, wherein the depth of the first portion increases in the direction of extension of the winding shaft toward the winding shaft.

[0045] Because the curvature of the electrode winding layer is greater closer to the winding shaft, the connecting tabs overlap more, causing the thickness of the tab stack to gradually increase from the outside to the inside. This allows the welding power to also gradually increase from the outside to the inside, forming a welding area with increasing depth from the outside to the inside, thus improving the welding quality of the welding area.

[0046] In some embodiments, the welding area of ​​the conductive element and the tab stack structure includes a first portion located in the second tab stack area and a second portion located in the first tab stack area, wherein the depth of the first portion is less than the depth of the second portion in the extension direction of the winding shaft.

[0047] Considering that the number of electrode stacking layers in the first electrode stacking region is relatively small and the molten pool depth is relatively small without burn-through, the welding power used when welding the first electrode stacking region can be lower than that used when welding the second electrode stacking region, thereby improving the welding quality of the second part of the first electrode stacking region and reducing the risk of electrode burn-through.

[0048] In some embodiments, at least a portion of the plurality of tabs are rectangular or parallelogram-shaped.

[0049] Considering that rectangular or parallelogram-shaped tabs can achieve a smaller top spacing between tabs, which is beneficial to increase the overlap of adjacent tabs, thereby increasing the thickness of the tab stack and reducing the risk of tab burn-through.

[0050] In some embodiments, the winding structure is a cylindrical winding structure having a central hole, and the minimum distance r1 between the winding shaft and the root of the first electrode tab satisfies:

[0051] r1≥h0+0.8*R;

[0052] Where h0 is the height of the first electrode tab in its unbent state along the extension direction of the winding shaft, and R is the radius of the cross-section of the central hole at the end of the winding structure.

[0053] The minimum distance r1 is greater than or equal to the sum of the height h0 of the first tab and 0.8 times the radius R of the center hole. This means that the radius of the center hole covered by the first tab closest to the winding shaft after bending from the outside to the inside does not exceed 20%, thereby reducing the obstruction of the center hole after the tab is bent, so as not to affect the electrolyte injection, and reduce the risk of short circuit caused by the tab being inserted downward or torn during electrolyte injection.

[0054] In some embodiments, the minimum distance r1 between the winding shaft and the root of the first electrode tab satisfies: r1≥h0+R.

[0055] The minimum distance r1 is greater than or equal to the sum of the height h0 of the first tab and the radius R of the center hole. This means that the first tab closest to the winding shaft does not cover the center hole after bending from the outside to the inside, thus more effectively avoiding the influence of the tab blocking the center hole on the electrolyte injection.

[0056] In some embodiments, the plurality of tabs includes a first tab group and a second tab group, wherein the plurality of electrode windings in which the first tab group is located are located outside at least one electrode winding of the second tab group, and in the extension direction of the winding shaft, the minimum height h1 of the first tab group in its unbent state is greater than the maximum height h2 of the second tab group in its unbent state.

[0057] By making the maximum height h2 of the second tab group located inside the first tab group smaller than the minimum height h1 of the first tab group, the first tab connected to the welding area can be closer to the winding start end, which helps to reduce the risk of overcurrent in the first tab. Moreover, the smaller tab height of the first tab group can reduce or avoid covering the center hole, effectively avoiding the impact of the tab blocking the center hole on electrolyte injection.

[0058] In some embodiments, the second electrode group includes the first electrode, and in the extension direction of the winding shaft, the height h2 of the second electrode group in its unbent state decreases toward the direction closer to the winding shaft.

[0059] By decreasing the height of each loop of the first electrode group from the outside to the inside, the stacked area of ​​the second electrode can extend more towards the winding shaft, thereby increasing the range of the stacked area of ​​the second electrode. This, in turn, helps to increase the size of the welding area in the first part of the stacked area of ​​the second electrode, improves the welding quality of the welding area, and reduces the risk of electrode burn-through or incomplete welding.

[0060] In some embodiments, the housing includes a housing and an end cap, one end of the housing having an opening, the end cap covering the opening, the housing including a side wall and a bottom wall, the side wall surrounding the outside of the electrode assembly, the bottom wall being disposed opposite to the opening, and the wall portion of the housing being the end cap or the bottom wall.

[0061] The conductive component is electrically connected to the electrode terminals located on the bottom wall of the end cap or housing, and is welded to the electrode tab stack structure of the electrode assembly. This improves the welding quality of the welding area, reduces the risk of short circuits in individual battery cells, and enhances safety in use.

[0062] In one aspect of this disclosure, a battery is provided, comprising the aforementioned battery cell. A battery using the aforementioned battery cell can effectively improve safety during use.

[0063] In one aspect of this disclosure, an electrical device is provided, including the aforementioned battery. The electrical device employing the aforementioned battery can effectively improve safety during use. Attached Figure Description

[0064] To more clearly illustrate the technical solutions of the embodiments of this disclosure, the accompanying drawings used in the embodiments of this disclosure will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on the drawings without creative effort.

[0065] This disclosure will become clearer with reference to the accompanying drawings and the following detailed description, wherein:

[0066] Figure 1 These are schematic diagrams of the structure of some embodiments of the electrical equipment according to this disclosure;

[0067] Figure 2 This is an exploded view of some embodiments of the battery according to the present disclosure;

[0068] Figure 3 This is a schematic diagram showing the connection of multiple battery cells according to some embodiments of the battery disclosed herein;

[0069] Figure 4A This is an exploded view of some embodiments of the battery cell according to the present disclosure;

[0070] Figure 4B This is a schematic longitudinal section diagram of a battery cell according to some embodiments of the present disclosure via a winding shaft;

[0071] Figure 4C This is an exploded schematic diagram of the electrode assembly and conductive elements in some embodiments of the battery cell according to this disclosure;

[0072] Figure 5 This is a cross-sectional schematic diagram of the winding structure according to some embodiments of the battery cell of this disclosure;

[0073] Figure 6 This is a schematic diagram of the electrode sheet and tab in the unfolded state according to some embodiments of the battery cell of this disclosure;

[0074] Figure 7 This is a schematic cross-sectional view of the electrode stacking structure and the welding of conductive components according to some embodiments of the battery cell of this disclosure;

[0075] Figure 8 This is a cross-sectional schematic diagram of multiple tab stacking regions of a tab stacking structure according to some embodiments of the battery cell of this disclosure;

[0076] Figure 9 This is a schematic diagram showing the distribution of the welding area in multiple tab stacking areas of the tab stacking structure in some embodiments of the battery cell according to this disclosure;

[0077] Figure 10 This is a schematic diagram showing the dimensions of various portions of the welding area in some embodiments of the battery cell according to this disclosure;

[0078] Figure 11 This is a schematic diagram showing the overlap of adjacent tabs in different tab stacking areas in some embodiments of the battery cell according to this disclosure;

[0079] Figure 12 and Figure 13 These are schematic diagrams showing the dimensions of different shaped tabs connected to the electrode sheets in some embodiments of the battery cell according to this disclosure.

[0080] Figure 14 This is a schematic diagram showing the dimensions of the bent tabs and center hole in some embodiments of the battery cell according to this disclosure;

[0081] Figure 15 This is a schematic diagram showing the height of the tabs in an unbent state in some other embodiments of the battery cell according to this disclosure;

[0082] Figure 16 yes Figure 15 A cross-sectional schematic diagram of the stacked area of ​​multiple electrodes after the middle electrode is bent toward the central hole.

[0083] It should be understood that the dimensions of the various parts shown in the accompanying drawings are not drawn to actual scale. Furthermore, the same or similar reference numerals denote the same or similar components.

[0084] Explanation of reference numerals in the attached figures:

[0085] 10-Electrode assembly; 10a-First electrode; 10b-Second electrode; 10c-Separator; 100-Wound structure; 110-Center hole; 11-Current collector substrate; 12-Active material layer; 13-Electrode tab; 130-Electrode tab stacking structure; 130a-First electrode tab stacking area; 130b-Second electrode tab stacking area; 130c-Third electrode tab stacking area; 131-First electrode tab; 132-Second electrode tab; 13a-First electrode tab group; 13b-Second electrode tab group;

[0086] 21, 22 - Conductive components;

[0087] 30 - Welding area; 31 - First part; 32 - Second part; 33 - Third part;

[0088] 40-Battery cell; 4A-Casing; 41-Housing; 411-Opening; 412-Through hole; 42-End cap; 421-Pressure relief component; 43-Electrode terminal; 44-Insulator; 45-Electrode lead-out section; 46-Busbar;

[0089] 50 - Battery; 51 - Box body; 52 - Box lid;

[0090] 60 - Vehicles;

[0091] wd - winding direction; CL - winding axis; WS - winding start end. Detailed Implementation

[0092] The embodiments of this disclosure will be further described in detail below with reference to the accompanying drawings and examples. The following detailed description of the embodiments and the accompanying drawings are used to illustrate the principles of this disclosure by way of example, but should not be used to limit the scope of this disclosure, that is, this disclosure is not limited to the described embodiments.

[0093] In the description of this disclosure, it should be noted that, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," "outer," etc., indicating orientation or positional relationships are only for the convenience of describing this disclosure 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 disclosure. Furthermore, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. "Vertical" is not vertical in the strict sense, but within the allowable tolerance range. "Parallel" is not parallel in the strict sense, but within the allowable tolerance range.

[0094] The directional terms used in the following description refer to the directions shown in the figures and are not intended to limit the specific structure of this disclosure. It should also be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this disclosure based on the specific circumstances.

[0095] The following detailed description of some embodiments of the present invention is provided in conjunction with the accompanying drawings. Unless otherwise specified, features in the following embodiments can be combined with each other.

[0096] In this disclosure, "multiple" means two or more (including two).

[0097] In this embodiment of the disclosure, the battery cell can be a secondary battery, which refers to a battery cell that can be recharged to activate the active materials and continue to be used after the battery cell has been discharged.

[0098] The battery cell can be a lithium-ion battery, sodium-ion battery, sodium-lithium-ion battery, lithium metal battery, sodium metal battery, lithium-sulfur battery, magnesium-ion battery, nickel-metal hydride battery, nickel-cadmium battery, lead-acid battery, etc., and the embodiments of this application are not limited to this.

[0099] A single battery cell typically includes an electrode assembly. The electrode assembly includes multiple electrodes and spacers positioned between adjacent electrodes. The multiple electrodes may include positive and negative electrodes with opposite polarities. During the charging and discharging process of the battery cell, active ions (such as lithium ions) repeatedly insert and extract between the positive and negative electrodes. The spacers, positioned between the positive and negative electrodes, prevent short circuits between the positive and negative electrodes while allowing active ions to pass through.

[0100] In some embodiments, the positive electrode may include a positive current collector substrate and a positive active material layer disposed on at least one surface of the positive current collector substrate.

[0101] As an example, the positive current collector substrate has two surfaces opposite each other in its own thickness direction, and the positive active material layer is disposed on either or both of the two opposite surfaces of the positive current collector substrate.

[0102] As an example, the positive electrode current collector substrate can be a metal foil or a composite current collector. For example, as a metal foil, silver-treated aluminum or stainless steel, stainless steel, copper, aluminum, nickel, carbon electrodes, carbon, nickel, or titanium, etc., can be used. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector can be formed by applying a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) onto a polymer material base material (such as a polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc. base material).

[0103] As an example, the positive electrode active material layer may include at least one of the following materials: lithium phosphate, lithium transition metal oxide, and their respective modified compounds. However, this disclosure is not limited to these materials, and other conventional materials that can be used as positive electrode active material layers in batteries may also be used. These positive electrode active material layers may be used alone or in combination of two or more. Examples of lithium phosphate include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO4), lithium manganese phosphate and carbon composites, lithium iron manganese phosphate, and lithium iron manganese phosphate and carbon composites. Examples of lithium transition metal oxides include, but are not limited to, lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, and lithium nickel cobalt manganese oxide (such as LiNi). 1 / 3 Co 1 / 3Mn 1 / 3 O2 (also known as NCM) 333 LiNi 0.5 Co 0.2 Mn 0.3 O2 (also known as NCM) 523 LiNi 0.5 Co 0.25 Mn 0.25 O2 (also known as NCM) 211 LiNi 0.6 Co 0.2 Mn 0.2 O2 (also known as NCM)622 LiNi 0.8 Co 0.1 Mn 0.1 O2 (also known as NCM) 811 ), lithium nickel cobalt aluminum oxide (such as LiNi) 0.85 Co 0.15 Al 0.05 At least one of O2 and its modified compounds.

[0104] In some implementations, the negative electrode may include a negative current collector substrate.

[0105] As an example, the negative electrode current collector substrate can be a metal foil, a foamed metal, or a composite current collector. For example, as a metal foil, it can be silver-treated aluminum or stainless steel, stainless steel, copper, aluminum, nickel, carbon electrodes, carbon, nickel, or titanium, etc. Foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloy, or foamed carbon, etc. Composite current collectors can include a polymer material base layer and a metal layer. Composite current collectors can be formed by applying a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) onto a polymer material base material (such as a base material of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0106] As an example, the negative electrode sheet may include a negative electrode current collector substrate and a negative electrode active material layer disposed on at least one surface of the negative electrode current collector substrate.

[0107] As an example, the negative electrode current collector substrate has two surfaces opposite each other in its own thickness direction, and the negative electrode active material layer is disposed on either or both of the two opposite surfaces of the negative electrode current collector substrate.

[0108] As an example, the negative electrode active material layer may employ a type of negative electrode active material layer known in the art for use in battery cells. As an example, the negative electrode active material layer may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate, etc. Silicon-based materials may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. Tin-based materials may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, this disclosure is not limited to these materials, and other conventional materials that can be used as negative electrode active material layers in batteries may also be used. These negative electrode active material layers may be used alone or in combination of two or more.

[0109] In some embodiments, the positive electrode current collector substrate can be made of aluminum, and the negative electrode current collector substrate can be made of copper.

[0110] In some embodiments, the electrode assembly further includes an isolator disposed between the positive and negative electrodes.

[0111] In some embodiments, the separator is a separator membrane. This disclosure does not impose any particular limitation on the type of separator membrane; any known porous separator membrane with good chemical and mechanical stability can be selected.

[0112] As an example, the main material of the separator can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramic. The separator can be a single-layer film or a multi-layer composite film, without particular limitation. When the separator is a multi-layer composite film, the materials of each layer can be the same or different, without particular limitation. The separator can be a separate component located between the positive and negative electrode plates, or it can be attached to the surface of the positive electrode plate and / or the surface of the negative electrode plate.

[0113] In some embodiments, the separator is a solid electrolyte. The solid electrolyte is disposed between the positive and negative electrode plates, serving both to transport ions and to isolate the positive and negative electrodes.

[0114] In some embodiments, the battery cell also includes an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. This disclosure does not impose specific limitations on the type of electrolyte; it can be selected according to requirements. The electrolyte can be liquid, gel, or solid.

[0115] As an example, liquid electrolytes include electrolyte salts and solvents.

[0116] In some embodiments, the electrolyte salt may be selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalate borate, lithium dioxalate borate, lithium difluorodioxalate phosphate, and lithium tetrafluorooxalate phosphate.

[0117] In some embodiments, the solvent may be selected from at least one of ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butyl carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone. The solvent may also be an ether solvent. Ether solvents may include one or more of ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyl tetrahydrofuran, diphenyl ether, and crown ethers.

[0118] As an example, gel electrolytes include a polymer-based backbone network combined with an ionic liquid—a lithium salt.

[0119] As an example, solid electrolytes include polymer solid electrolytes, inorganic solid electrolytes, and composite solid electrolytes.

[0120] As an example, polymer solid electrolytes can be polyether (polyoxyethylene), polysiloxane, polycarbonate, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, monoionic polymers, polyionic liquids-lithium salts, cellulose, etc.

[0121] As an example, inorganic solid electrolytes can be one or more of the following: oxide solid electrolytes (crystalline perovskite, sodium superconducting ion conductor, garnet, amorphous LiPON thin film), sulfide solid electrolytes (crystalline lithium superconducting ion conductor (lithium-germanium-phosphorus-sulfur, sulfosilium-germanium), amorphous sulfides), halide solid electrolytes, nitride solid electrolytes, and hydride solid electrolytes.

[0122] As an example, composite solid electrolytes are formed by adding inorganic solid electrolyte fillers to polymer solid electrolytes.

[0123] In some embodiments, the electrode assembly includes a wound structure. The positive electrode, negative electrode, and separator are wound into a wound structure.

[0124] As an example, one or more positive electrode plates and one or more negative electrode plates can be set respectively, and multiple positive electrode plates and multiple negative electrode plates can be stacked alternately.

[0125] As an example, multiple positive electrode sheets can be set, and negative electrode sheets are folded to form multiple stacked folded segments, with a positive electrode sheet sandwiched between adjacent folded segments.

[0126] As an example, both the positive and negative electrode sheets are folded to form multiple stacked folded segments.

[0127] As an example, multiple separators can be provided, each positioned between any adjacent positive or negative electrode plates.

[0128] As an example, the separator can be continuously arranged between any adjacent positive or negative electrode plates by folding or rolling.

[0129] In some embodiments, the electrode assembly can be cylindrical, flat, or polygonal, etc.

[0130] In some embodiments, the electrode assembly includes tabs that can conduct current from the electrode assembly. The tabs include a positive tab and a negative tab, which are respectively connected to the positive current collector substrate and the negative current collector substrate. The tabs can be formed by cutting or trimming the current collector substrate, or they can be connected to the side of the current collector substrate by welding.

[0131] In some embodiments, the battery cell may include a housing. The housing is used to encapsulate components such as electrode assemblies and electrolytes. The housing may be made of steel, aluminum, plastic (such as polypropylene), composite metal (such as copper-aluminum composite), or aluminum-plastic film, etc.

[0132] As an example, the battery cell can be a cylindrical battery cell, a prismatic battery cell, a pouch battery cell, or a battery cell of other shapes. Prismatic battery cells include prismatic battery cells, blade-shaped battery cells, and multi-prismatic batteries, such as hexagonal prismatic batteries. This disclosure does not impose any particular limitations.

[0133] The battery mentioned in the embodiments of this disclosure refers to a single physical module comprising one or more battery cells to provide higher voltage and capacity.

[0134] In some embodiments, the battery can be a battery module. When there are multiple battery cells, the multiple battery cells are arranged and fixed to form a battery module. The battery module may include multiple battery cells connected in series, parallel, or in a mixed configuration.

[0135] In some embodiments, the battery can be a battery pack, which includes a housing and individual battery cells, with the individual battery cells or battery modules housed within the housing.

[0136] In some embodiments, the housing may be part of the vehicle's chassis structure. For example, a portion of the housing may be at least a part of the vehicle's floor, or a portion of the housing may be at least a part of the vehicle's crossbeams and longitudinal beams.

[0137] In some embodiments, the battery can be an energy storage device. Energy storage devices include energy storage containers, energy storage cabinets, etc.

[0138] In some battery cells of related technologies, when the tabs at the end of the electrode assembly are welded to the current collector, there is a possibility of welding quality problems such as burn-through of the tabs or incomplete welding, which may affect the safety of the battery.

[0139] In view of this, the present disclosure provides a battery cell, a battery, and an electrical device that can improve the safety of battery use.

[0140] The battery cells of this disclosure are applicable to various types of batteries. The battery may include a housing and a battery module. The housing provides space for the battery module, which is mounted within the housing. The housing may be made of metal. The battery module may include multiple battery cells connected in series, parallel, or a combination thereof. A battery cell is the smallest unit constituting a battery. A battery cell includes electrode components capable of undergoing electrochemical reactions.

[0141] The battery disclosed in this embodiment is applicable to various battery-powered devices. These devices can include mobile phones, portable devices, laptops, electric vehicles, electric cars, ships, spacecraft, electric toys, and power tools, etc. For example, spacecraft include airplanes, rockets, space shuttles, and spacecraft; electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys; and power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers. This disclosure does not impose any particular limitation on the aforementioned electrical devices. The battery can also be used to power vehicles and other electrical devices, for example, to provide power for vehicle operation or driving.

[0142] Figure 1 This is a structural schematic diagram of some embodiments of the electrical equipment according to the present disclosure. For convenience, a vehicle is used as an example for explanation. The vehicle 60 can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle, and the new energy vehicle can be a pure electric vehicle or a hybrid vehicle, etc. A battery 50 can be installed at the bottom, front, or rear of the vehicle 60.

[0143] Battery 50 can be used to power vehicle 60. For example, battery 50 can serve as the operating power source for vehicle 60, supporting its electrical system, such as the power requirements for starting, navigation, and operation. Battery 50 can not only serve as the operating power source for vehicle 60, but also as its driving power source, replacing or partially replacing fuel or natural gas to provide propulsion for vehicle 60.

[0144] The interior of vehicle 60 may also house an axle, wheels, a motor, and a controller. The controller controls the power supply from battery 50 to the motor. For example, when vehicle 60 uses battery 50 as its drive power source, battery 50 replaces or partially replaces fuel or natural gas to provide the motor with the power needed for constant speed and acceleration. The motor drives the axle to rotate, thereby rotating the wheels.

[0145] Figure 2 This is an exploded schematic diagram of some embodiments of the battery according to the present disclosure. Figure 3 This is a schematic diagram showing the connection of multiple battery cells according to some embodiments of the battery disclosed herein.

[0146] refer to Figure 2 In some embodiments, the battery 50 includes a housing 51, a cover 52 covering the opening side of the housing 51, and one or more battery cells 40 disposed in the housing 51. The housing 51 and the cover 52 provide housing space for the battery cells 40 and provide functions such as cooling, sealing and impact protection, and can also prevent liquids or other foreign objects from adversely affecting the charging, discharging or safety of the battery cells.

[0147] The box body 51 and the lid 52 can be of various shapes, such as cuboids or cylinders. The box body 51 can be a hollow structure open on one side, and the lid 52 can be a plate-like structure that closes onto the open side of the box body 51 to form an internal storage space. In another embodiment, the box body 51 is a hollow structure open on one side, and the lid 52 is also a hollow structure open on one side. The open side of the lid 52 closes onto the open side of the box body 51 to form an internal storage space.

[0148] refer to Figure 2 and Figure 3 The individual battery cells 40 are electrically connected, such as in series, parallel, or a combination thereof, to achieve the required electrical performance parameters of the battery 50. A combination thereof refers to multiple battery cells 40 being connected in both series and parallel. Adjacent battery cells 40 can be electrically connected through busbars 44. Multiple battery cells 40 are arranged in rows, and one or more rows of battery cells 40 can be arranged in the housing as needed.

[0149] In some embodiments, the individual battery cells 40 of the battery 50 can be arranged along at least one of the length and width directions of the housing. At least one row or column of battery cells 40 can be provided as needed. Alternatively, one or more layers of battery cells 40 can be provided along the height direction of the battery 50 as required.

[0150] In some embodiments, multiple battery cells 40 may first be connected in series, parallel, or in a mixed manner to form a battery module, and then the multiple battery modules may be connected in series, parallel, or in a mixed manner to form a whole, which is then housed in the housing 51. In other embodiments, all battery cells 40 are directly connected in series, parallel, or in a mixed manner, and then the whole composed of all battery cells 40 is housed in the housing.

[0151] Figure 4A This is an exploded view of some embodiments of the battery cell according to the present disclosure. Figure 4B This is a schematic longitudinal section diagram of a battery cell according to some embodiments of the present disclosure via a winding shaft. Figure 4C This is an exploded schematic diagram of the electrode assembly and conductive elements in some embodiments of the battery cell according to this disclosure. Figure 5 This is a schematic cross-sectional view of the winding structure according to some embodiments of the battery cell of this disclosure.

[0152] refer to Figures 3 to 5 In some embodiments, the battery cell 40 includes an electrode assembly 10, a housing 4A, electrode terminals 42, and conductive elements 21 and 22. The electrode assembly 10 includes a plurality of electrodes 10a and 10b and a spacer 10c disposed between adjacent electrodes 10a and 10b of opposite polarity. The plurality of electrodes 10a and 10b and the spacer 10c are wound along a winding direction wd to form a winding structure 100.

[0153] exist Figure 5 In the winding structure 100, multiple electrodes may include an electrode 10a serving as a positive electrode and an electrode 10b serving as a negative electrode. The electrode coils formed by the electrodes 10a and 10b in the winding structure 100 are arranged at least partially alternately from the outside to the inside. A separator 10c may be disposed between the electrodes 10a and 10b in the form of a separator film. In other embodiments, the electrode 10a may also serve as a negative electrode, and the electrode 10b as a positive electrode.

[0154] refer to Figure 4A and Figure 4B The housing 4A has a cavity for accommodating the electrode assembly 10. Electrode terminals 42 are disposed on the wall of the housing 4A and are electrically connected to the conductive element 21. The electrode terminals 42 may be disposed on the side wall or bottom wall of the housing 4A.

[0155] The cavity of the housing 4A accommodates the electrode assembly 10 and the electrolyte. The shape of the housing 4A can be determined according to the shape of one or more electrode assemblies 10 contained in the cavity, for example, the shape of the housing 4A is a hollow cuboid, a hollow cube, or a hollow cylinder.

[0156] The outer casing 4A may include a housing 41 and an end cap 42. The housing 41 is a hollow structure with an opening 411 at one or both ends, and its material can be one or more, such as copper, iron, aluminum, steel, aluminum alloy, plastic, etc. The end cap 42 can be made of metal or non-metal and can be fixedly connected to the housing 41 by welding, bonding or fastener connection.

[0157] refer to Figure 4B The housing 41 has an opening 411 at one end, and an end cap 42 covers the opening 411. The housing 41 includes a side wall 414 and a bottom wall 413. The side wall 414 surrounds the outside of the electrode assembly 10, and the bottom wall 413 is disposed opposite to the opening 411. The wall portion of the outer casing 4A is either the end cap 42 or the bottom wall 413. Accordingly, the electrode terminal 42 can be disposed on the end cap 42 or on the bottom wall 413.

[0158] For a cylindrical battery cell, the casing 41 can be a hollow cylindrical structure with an opening 411 at one end, and the end cap 42 can be a disc-shaped structure that matches the opening 411. The electrode terminals 42 can be located on the bottom wall 413 of the casing 41 on the side away from the end cap 42. Figure 4A and Figure 4B In the casing, the bottom wall 413 has a through hole 412, through which electrode terminals 42 can be disposed via electrode leads 45 and insulating members 42. The electrode leads 45 may at least partially protrude from the outer surface of the bottom wall 413 to facilitate electrical connection between different battery cells 40 via the busbar 46. The insulating members 42 are used to insulate the electrode leads 45 from the casing 41 and may be made of rubber or plastic. Optionally, openings are provided at both ends of the casing and are covered by end caps, on which the electrode leads and electrode terminals may be disposed.

[0159] refer to Figure 4A A pressure relief component 421 can be provided on the end cap 42. A pressure relief component is an element or part that is activated to release internal pressure or temperature when the internal pressure or temperature of a battery cell reaches a predetermined threshold. This threshold design varies depending on design requirements. The threshold may depend on one or more materials of the positive electrode, negative electrode, electrolyte, and separator in the battery cell. The pressure relief component can take the form of an explosion-proof valve, gas valve, pressure relief valve, or safety valve, and can specifically employ pressure-sensitive or temperature-sensitive elements or structures. That is, when the internal pressure or temperature of the battery cell reaches the predetermined threshold, the pressure relief component actuates or a weak structure within the pressure relief component is destroyed, thereby forming an opening or channel for the release of internal pressure or temperature.

[0160] The emissions from individual battery cells mentioned here include, but are not limited to: electrolyte, dissolved or broken positive and negative electrode plates, fragments of the separator, high-temperature and high-pressure gases generated by the reaction (such as CH4, CO and other combustible gases), flames, etc.

[0161] refer to Figures 4A to 4C Conductive elements 21 and 22 can be located on both sides of the electrode assembly 10 along the extending direction of the winding axis of the winding structure 100, or on one side of the electrode assembly 10 along the extending direction of the winding axis of the winding structure 100. Figure 4B In this configuration, conductive element 21 is welded to the tab at one end of the electrode assembly 100 and to the electrode lead-out portion 45. Conductive element 22 is welded to the tab at the other end of the electrode assembly 100 and to the end cap 42. Conductive elements 21 and 22 can serve as current collectors to achieve electrical connections between the electrode assembly, electrode terminals, and end caps. The conductive elements can be metallic conductors, such as copper, iron, aluminum, steel, or aluminum alloys. In some embodiments, the conductive elements may include a current collector or other structures.

[0162] Figure 6 This is a schematic diagram of the electrode sheet and tab in the unfolded state in some embodiments of the battery cell according to this disclosure. Figure 7 This is a schematic cross-sectional view of the electrode stacking structure and the welding of conductive components according to some embodiments of the battery cell of this disclosure. Figure 8 This is a cross-sectional schematic diagram of multiple tab stacking regions of a tab stacking structure according to some embodiments of the battery cell of this disclosure.

[0163] refer to Figure 6 At least one of the plurality of electrodes in the electrode assembly 10 includes a current collector substrate 11 and a plurality of tabs 13. The electrode may also include an active material layer 12 covering at least one surface of the current collector substrate 11.

[0164] The plurality of tabs 13 are connected to at least one side of the current collector substrate 11 extending along the winding direction wd, and are arranged at intervals along the winding direction wd. The plurality of tabs 13 may be connected to one side of the current collector substrate 11 extending along the winding direction wd, or they may be connected to two sides of the current collector substrate 11 extending along the winding direction wd.

[0165] In some embodiments, the plurality of tabs 13 may be formed by cutting or trimming the current collector substrate. In other embodiments, the plurality of tabs 13 may be welded to the sides of the current collector substrate 11 respectively.

[0166] refer to Figure 7 At least a portion of the plurality of tabs 13 are bent toward the winding axis CL of the winding structure 100, forming a tab stack structure 130 at the end of the winding structure 100. The tab stack structure 130 is electrically connected to the electrode terminals 42 disposed on the wall of the housing 4A via conductive elements 21, 22 (e.g., current collectors). Specifically, the conductive elements 21, 22 are welded to the tab stack structure 130.

[0167] The conductive components 21 and 22 can form continuous or discrete welding areas 30 with the tab stack structure 130. When the conductive components 21 and 22 and the tab stack structure 130 are welded by means of laser or other methods, the welding area 30 is a liquid metal part that is heated and melted into a certain geometric shape, i.e., a weld pool.

[0168] refer to Figure 7 and Figure 8 The electrode stacking structure 130 includes a first electrode stacking region 130a and a second electrode stacking region 130b arranged from the outside to the inside along a direction close to the winding axis CL. Figure 7 and Figure 8The figure shows a partial cross-section of the electrode lugs connected to the individual windings of the electrode after winding, which are bent toward the winding axis CL and stacked sequentially. The winding axis CL is drawn with a dashed line. For ease of representation, other electrodes and spacers in the winding structure are omitted from the figure.

[0169] The number of tab stack layers in the first tab stack region 130a increases along the direction closer to the winding axis CL. The number of tab stack layers in the second tab stack region 130b is equal along the direction closer to the winding axis CL. Here, the number of tab stack layers at a certain position refers to the number of tab stack layers connected to different electrode windings at that position in the tab stack structure 130, that is, the number of turns of the electrode windings corresponding to each tab stacked at that position.

[0170] refer to Figure 8 In the first tab stacking region 130a, the number of tab stack layers decreases as the distance from the winding axis CL increases. For tabs of approximately the same height, the number of stack layers gradually increases from the outermost layer of 1 to more than 10 layers. The position where the second tab stacking region 130b connects to the first tab stacking region 130a is actually the position where the number of tab stack layers in the first tab stacking region 130a no longer increases. The number of tab stack layers remains equal at all positions in the second tab stacking region 130b along the direction closest to the winding axis CL.

[0171] refer to Figure 6 The first tab 131 is defined as the tab closest to the winding start end WS of the current collector substrate among the plurality of tabs 13. For ease of illustration, the first tab 131 is... Figure 6 The electrode sheet has been flattened, and its length direction is actually consistent with the winding direction. The winding start end WS is the starting position when the electrode sheet is wound, located at the innermost side of the winding structure. Correspondingly, the second electrode tab stacking area 130 can extend to the electrode sheet winding loop where the first electrode tab 131 is located.

[0172] Figure 9 This is a schematic diagram showing the distribution of the welding areas in multiple tab stacking regions of a tab stacking structure according to some embodiments of the battery cell of this disclosure. (See reference) Figure 9 At least a portion of the welding area 30 of the conductive elements 21 and 22 and the tab stack structure 130 is located in the second tab stack region 130b. In some embodiments, the welding area 30 is entirely located in the second tab stack region 103b; in other embodiments, a portion of the welding area 30 is located in the second tab stack region 103b, and another portion is located in other parts of the tab stack structure outside the second tab stack region 103b.

[0173] Since the number of tab stacking layers in the second tab stacking region 130b is equal, when the conductive elements 21 and 22 are welded to the tab stacking structure 130 formed at the end of the winding structure 100, the second tab stacking region 130b has more tab stacking layers and a higher stacking thickness than other tab stacking regions. Therefore, it is not easy to be welded through when welding with the conductive elements 21 and 22, thereby improving the welding quality of the welding region 30 and reducing the risk of short circuit caused by the diaphragm 10c or electrode being burned during welding.

[0174] refer to Figures 7 to 9 In some embodiments, the welding area 30 includes a first portion 31 located in the second tab stack area 130b and a second portion 32 located in the first tab stack area 130a. The first tab stack area 130a is located outside the second tab stack area 130b, and the number of tab stack layers increases from the outside to the inside. By welding the second tab stack area 130b and the first tab stack area 130a to the conductive component through the first portion 31 and the second portion 32 of the welding area 30, respectively, the overall size of the welding area 30 can be increased, thereby improving the welding strength, reducing the resistance of the welding area 30, and thus reducing the risk of overcurrent. The second portion 32 can be connected to the first portion 31 or spaced apart from the first portion 31.

[0175] In some embodiments, the tab stack structure 130 further includes a third tab stack region 130c located on the side of the second tab stack region 130b adjacent to the winding shaft CL, and the welding region 30 further includes a third portion 33 located in the third tab stack region 130c.

[0176] The number of tab stacking layers in the third tab stacking region 130c is located inside the second tab stacking region 130b, and the number of tab stacking layers decreases from the outside to the inside. By welding the third tab stacking region 130c with the conductive parts 21 and 22, the overall size of the welding region 30 can be increased, thereby improving the welding strength, reducing the resistance of the welding region 30, and thus reducing the risk of overcurrent.

[0177] The welding area can be distributed at multiple locations on the conductive component, including continuous or discrete weld segments located at different radial or circumferential positions. (Reference) Figure 9 As can be seen, the welding area 30 consists of multiple segments, and the shape can be a straight segment, a curved segment, or a straight segment and a curved segment connected together.

[0178] Figure 10This is a schematic diagram showing the dimensions of various portions of the welding area in some embodiments of the battery cell according to this disclosure. For ease of understanding, the welding areas distributed at various locations are schematically arranged within rectangular areas, and dashed lines are used to indicate the portions of the welding areas corresponding to different tab stacking areas. Figure 10 In the middle, the first part 31 corresponds to the second electrode stacking region 130b, the second part 32 corresponds to the first electrode stacking region 130a, and the third part 33 corresponds to the third electrode stacking region 130c.

[0179] refer to Figure 10 In some embodiments, the ratio S1 / S of the area S1 of the first portion 31 to the area S of the welding region 30 satisfies: S1 / S ≥ 70%. Here, the area S is the total area of ​​the welding region 30. Figure 10 The area S in the middle is the sum of the areas S1, S2, and S3. (Reference) Figure 7 The welding area 30 shown may have an irregular three-dimensional shape. Its area can be calculated as the projected area of ​​the weld pool on the surface of the conductive part away from the tab stack structure.

[0180] Since the welding area 30 includes the first part 31, it may also include other parts. Therefore, the ratio S1 / S represents the proportion of the first part 31 in the welding area 30. Since the first part 31 is easier to obtain better welding quality, increasing this proportion is beneficial to improving the welding quality of the welding area 30. Therefore, by making the ratio S1 / S greater than or equal to 70%, the welding quality of the welding area 30 can be improved, and the risk of electrode tab burn-through or incomplete welding can be reduced.

[0181] Optionally, the ratio S1 / S of the area S1 of the first portion 31 to the area S of the welding region 30 satisfies: S1 / S ≥ 90%, for example, S1 / S equals 90%, 95%, 98%, or 100%. By further limiting the ratio S1 / S to be greater than or equal to 90%, the welding quality of the welding region 30 can be further improved, effectively reducing the risk of electrode tab burn-through or incomplete welding.

[0182] refer to Figure 9 and Figure 10 In some embodiments, the winding structure 100 is a cylindrical winding structure. The ratio L1 / L of the maximum radial length L1 of the first portion 31 in the radial direction of the cylindrical winding structure to the maximum radial length L of the welding area 30 in the radial direction of the cylindrical winding structure satisfies: L1 / L ≥ 70%. Here, the maximum radial length L is the maximum length of the welding area 30 in the radial direction. Figure 10 The maximum radial length L is the sum of the maximum radial lengths L1, L2 and L3.

[0183] When determining the maximum radial length of each part, the farthest and closest positions of each part of the welding area from the winding shaft CL can be selected, and the difference between the farthest and closest positions and the shortest distance from the winding shaft CL can be calculated, which is the maximum radial length of the corresponding part.

[0184] Since the welding area 30 includes the first part 31, it may also include other parts. Therefore, the ratio L1 / L represents the proportion of the first part 31 in the welding area 30. Since the first part 31 is easier to obtain better welding quality, increasing this proportion is beneficial to improving the welding quality of the welding area 30. Therefore, by making the ratio L1 / L greater than or equal to 70%, the welding quality of the welding area 30 can be improved and the risk of electrode tab burn-through or incomplete welding can be reduced.

[0185] Optionally, the ratio L1 / L of the maximum radial length L1 of the first portion 31 in the radial direction of the cylindrical winding structure to the maximum radial length L of the welding area 30 in the radial direction of the cylindrical winding structure satisfies: L1 / L ≥ 90%, for example, making L1 / L equal to 90%, 95%, 98%, or 100%. By further limiting the ratio L1 / L to be greater than or equal to 90%, the welding quality of the welding area 30 can be further improved, effectively reducing the risk of electrode tab burn-through or incomplete welding.

[0186] refer to Figure 6 In some embodiments, the minimum distance d between the current collector substrate 11 at the winding start end WS in the winding direction wd and the second tab 132 satisfies: d ≤ 1200 mm. The second tab 132 is defined as the tab among the plurality of tabs 13 that is welded to the conductive elements 21 and 22 and is closest to the winding start end WS. Here, the second tab 132 is located on the side of the first tab 131 away from the winding start end WS. In other embodiments, the second tab 132 may also be the first tab 131, i.e., the first tab of the electrode sheet is welded to the conductive elements 21 and 22.

[0187] The minimum distance d is not easily measured while the electrode is wound. It can be obtained by measuring the electrode in its flattened state. In this case, the winding direction wd is equivalent to being flattened along with the electrode and parallel to its length. Since the second tab 132 is both welded to the conductive elements 21 and 22 and is closest to the winding start end WS, its minimum distance d from WS reflects the range of the tab directly connected to the conductive elements 21 and 22 through the welding area 30.

[0188] The charge on the electrode sheet flows to the conductive element through the welding area between the multiple tabs and the conductive element. However, the portion of the electrode sheet between the second tab 132 and the winding start end has a higher charge flow towards the second tab 132, making it more susceptible to overcurrent. By making the minimum distance d less than or equal to 1200 mm, the range of tabs directly connecting the conductive elements 21 and 22 through the welding area 30 can be increased, reducing the risk of overcurrent in the second tab 132 and minimizing the risk of overheating of the tabs, which could affect the chemical properties within the electrode assembly 10.

[0189] Optionally, the minimum distance d satisfies: d ≤ 800 mm, for example, d equals 800 mm, 680 mm, 540 mm, 500 mm, etc. By further limiting the optional range of the minimum distance d, the range of the tabs directly connected to the conductive parts 21 and 22 through the welding area 30 can be increased to a greater extent, further reducing the risk of overcurrent in the first tab 131, thereby more effectively avoiding overheating of the tab and affecting the performance of the chemical substances in the electrode assembly 10.

[0190] refer to Figure 7 In some embodiments, in the extension direction of the winding shaft CL, the maximum value Hmax of the depth H of the welding region 30 and the thickness t of the conductive elements 21 and 22 satisfy: 1.5*t≤Hmax≤1.9*t. When the conductive elements 21 and 22 are welded to the stacked tabs, a weld pool is formed extending from the surface of the conductive elements 21 and 22 toward the tab side. Depending on the power used during welding and the overlap thickness, the ratio between the depth of the welding region 30 (i.e., the weld pool) and the thickness of the conductive elements 21 and 22 can satisfy a certain numerical range.

[0191] The depth H of the welding area 30 can be measured with reference to the surface of the conductive components 21 and 22 on the side away from the electrode assembly. For a certain weld pool, the depth of the weld pool is the distance from the deepest point of the weld pool to the surface of the conductive component along the extension direction of the winding shaft CL. The maximum value Hmax and the minimum value Hmin of the depth of the welding area 30 are the maximum and minimum values ​​of the distance from the deepest point of each part of the entire welding area 30 to the surface of the conductive component along the extension direction of the winding shaft CL.

[0192] For the maximum depth Hmax of the welding area 30, if the ratio of Hmax to the thickness t of the conductive parts 21 and 22 is too large, the risk of burn-through of the tab will increase; if the ratio is too small, the risk of incomplete soldering of the tab will increase. Therefore, by setting a specific range for the ratio of the maximum depth Hmax of the welding area 30 to the thickness t of the conductive parts 21 and 22, the risks of burn-through and incomplete soldering of the tab can be minimized.

[0193] Optionally, in the extension direction of the winding shaft CL, the maximum value Hmax of the depth H of the welding area 30 and the thickness t of the conductive parts 21 and 22 satisfy: 1.6*t ≤ Hmax ≤ 1.8*t, for example, Hmax is 1.6*t, 1.65*t, 1.7*t, 1.8*t, etc. By further limiting the selectable range of the ratio of the maximum value Hmax of the welding area 30 to the thickness t of the conductive parts 21 and 22, the risk of electrode burn-through and incomplete soldering can be effectively reduced.

[0194] In some embodiments, in the extension direction of the winding shaft CL, the minimum depth H of the welding area 30, Hmin, and the thickness t of the conductive elements 21 and 22 satisfy: 1.1*t ≤ Hmin ≤ 1.5*t. If the ratio of the minimum depth Hmin of the welding area 30 to the thickness t of the conductive elements 21 and 22 is too large, the risk of burn-through of the tab increases; conversely, if the ratio is too small, the risk of incomplete soldering of the tab increases. Therefore, by setting a specific range for the ratio of the minimum depth Hmin of the welding area 30 to the thickness t of the conductive elements 21 and 22, the risks of burn-through and incomplete soldering of the tab can be minimized.

[0195] Optionally, in the extension direction of the winding shaft CL, the minimum value Hmin of the depth H of the welding area 30 and the thickness t of the conductive parts 21 and 22 satisfy: 1.2*t ≤ Hmin ≤ 1.4*t, for example, Hmin is 1.2*t, 1.25*t, 1.3*t, 1.4*t, etc. By further limiting the selectable range of the ratio of the minimum value Hmin of the welding area 30 to the thickness t of the conductive parts 21 and 22, the risk of electrode burn-through and incomplete soldering can be effectively reduced.

[0196] The difference between the maximum value Hmax and the minimum value Hmin of the depth H of the welding area 30 reflects the range of depth variation in the welding area 30. If the difference is too large, it indicates that the depth of the welding area 30 varies greatly, which may increase the risk of local burn-through or incomplete weld. If the difference is too small, it indicates that the depth of the welding area 30 is relatively uniform. However, considering the difference in the thickness of the electrode stack, the risk of local burn-through or incomplete weld will increase in areas with thinner or thicker stack thickness.

[0197] Therefore, in some embodiments, in the extension direction of the winding shaft CL, the difference between the maximum value Hmax and the minimum value Hmin of the depth H of the welding area 30 (Hmax-Hmin) and the thickness t of the conductive parts 21 and 22 satisfy: 0.2*t≤(Hmax-Hmin)≤0.8*t, which helps to reduce the risk of local burn-through or incomplete soldering of the electrode tab.

[0198] Optionally, in the extension direction of the winding shaft CL, the difference between the maximum value Hmax and the minimum value Hmin of the depth H of the welding area 30 (Hmax-Hmin) and the thickness t of the conductive parts 21 and 22 satisfy: 0.3*t ≤ (Hmax-Hmin) ≤ 0.6*t, for example, (Hmax-Hmin) is 0.3*t, 0.4*t, 0.5*t, 0.6*t, etc. By further limiting the selectable range of the ratio of the difference (Hmax-Hmin) to the thickness t, the risk of local burn-through or incomplete soldering of the electrode tab can be further reduced.

[0199] Figure 11 This is a schematic diagram showing the overlap of adjacent tabs in different tab stacking regions in some embodiments of the battery cell according to this disclosure. Figure 12 and Figure 13 These are schematic diagrams showing the dimensions of different shaped tabs connected to the electrode sheets in some embodiments of the battery cell according to this disclosure. (Reference) Figure 11 The curvature of the electrode winding coil at different radius positions of the winding structure 100 varies with the radius; the smaller the radius, the greater the curvature of the electrode winding coil.

[0200] The number of tab stack layers mentioned above refers to the number of tab stack layers connected to different electrode windings. Considering that two or more adjacent tabs connected to the same electrode winding may overlap, when the number of tab stack layers in the second tab stack region 130a is equal along the direction close to the winding axis CL, the thickness of the tab stack increases in the second tab stack region 130a along the direction close to the winding axis because the degree of overlap between adjacent tabs closer to the winding axis is higher.

[0201] exist Figure 11 In the winding process, the radius of the electrode coil containing the root of the first tab (i.e., the first tab 131) closest to the winding start end WS is r1, while the radius of the electrode coil containing the root of the tab furthest from the winding start end WS is r2. Among the multiple tabs connected by each electrode coil, adjacent tabs may overlap after being bent inward. The greater the curvature of the electrode coil, the more adjacent tabs overlap among the multiple tabs 13 connected to it, and correspondingly, the thickness of the tab stack also increases.

[0202] exist Figure 12 and Figure 13 In this design, the tab 13 can be bent at its root 13r, and the root 13r of the tab 13 can be the location where the tab 13 is cut from the current collector substrate. The width of the top 13t of the tab 13 is defined as w, and the top spacing between adjacent tabs 13t is defined as e. (Reference) Figure 12 and Figure 13In some embodiments, in the winding direction wd, the top spacing e of adjacent tabs 13 among the plurality of tabs 13 satisfies: e≤0.5mm.

[0203] The larger the top spacing 'e' between adjacent tabs, the less overlap occurs or no overlap occurs after the adjacent tabs are bent inwards. Conversely, the smaller the top spacing 'e', ​​the greater the overlap occurs after the adjacent tabs are bent inwards. Therefore, by making the top spacing 'e' between adjacent tabs less than or equal to 0.5 mm, the degree of tab stacking can be increased, thereby obtaining a greater tab stack thickness and reducing the risk of tab burn-through.

[0204] Optionally, in the winding direction wd, the top spacing e of adjacent tabs among the plurality of tabs 13 satisfies: e ≤ 0.2 mm, for example, e can take values ​​of 0.2 mm, 0.18 mm, 0.12 mm, 0.06 mm, etc. By further limiting the top spacing e of the tabs to less than or equal to 0.2 mm, the thickness of the tab stack can be effectively increased, further reducing the risk of tab burn-through.

[0205] Considering that rectangular or parallelogram-shaped tabs can achieve a smaller tab top spacing, which is beneficial for increasing the overlap of adjacent tabs, refer to... Figure 12 and Figure 13 In some embodiments, at least a portion of the plurality of tabs 13 are rectangular or parallelogram-shaped, which can increase the thickness of the tab stack and reduce the risk of tab burn-through.

[0206] Because the curvature of the electrode winding layer is greater closer to the winding shaft CL, the connecting tabs overlap more, resulting in a gradual increase in the thickness of the tab stack from the outside to the inside. This allows the welding power to also gradually increase from the outside to the inside during welding. Therefore, in some embodiments, the depth of the first portion 31 in the extension direction of the winding shaft CL increases towards the direction closer to the winding shaft CL. This welding region 30 with its depth increasing from the outside to the inside is beneficial for improving the welding quality of the welding region 30.

[0207] In embodiments where the welding area 30 also includes a second portion 32 located in the first tab stack area 130a, considering that the number of tab stack layers in the first tab stack area 130a is relatively small and the depth of the molten pool is relatively small without burn-through, the welding power used when welding the first tab stack area 130a can be lower than the welding power used when welding the second tab stack area 130b. Therefore, in some embodiments, the depth of the first portion 31 in the extension direction of the winding shaft CL is made smaller than the depth of the second portion 32, thereby improving the welding quality of the second portion 32 of the first tab stack area 130a and reducing the risk of tab burn-through.

[0208] Figure 14This is a schematic diagram showing the dimensions of the bent tabs and center hole in some embodiments of the battery cell according to this disclosure. (See reference) Figure 5 , Figure 9 , Figure 12 , Figure 13 and Figure 14 In some embodiments, the winding structure 100 is a cylindrical winding structure with a central hole 110. The minimum distance r1 between the winding shaft CL and the root of the first electrode tab 131 satisfies: r1≥h0+0.8*R. h0 is the height of the first electrode tab 131 in the extension direction of the winding shaft CL in its unbent state, and R is the radius of the cross-section of the central hole 110 at the end of the winding structure 100.

[0209] In the winding direction wd, the first tab 131 is closest to the winding start end WS of the current collector substrate 11. When the first tab 131 bends inward, it is more likely to cover a portion of the central hole 110 compared to the tabs connected to the larger radius electrode winding. By making the minimum distance r1 greater than or equal to the sum of the height h0 of the first tab 131 and 0.8 times the radius R of the central hole 110, it is equivalent to the first tab 131 closest to the winding shaft CL covering no more than 20% of the radius of the central hole 110 after bending from the outside to the inside. This reduces the obstruction of the central hole 110 after the tab bends, so as not to affect the electrolyte injection and reduce the risk of short circuit caused by the tab being inserted downward or torn during electrolyte injection.

[0210] Optionally, the minimum distance r1 between the winding shaft CL and the root of the first tab 131 satisfies: r1 ≥ h0 + R. The minimum distance r1 is greater than or equal to the sum of the height h0 of the first tab 131 and the radius R of the central hole 110. This means that the first tab 131, which is closest to the winding shaft CL, does not cover the central hole 110 after being bent from the outside to the inside, thereby more effectively avoiding the influence of the tab blocking the central hole 110 on the electrolyte injection.

[0211] Figure 15 This is a schematic diagram showing the height of the tabs in an unbent state in some other embodiments of the battery cell according to this disclosure. Figure 16 yes Figure 15 A cross-sectional schematic diagram of the stacked area of ​​multiple electrodes after the middle electrode is bent towards the central hole. (Reference) Figure 15 and Figure 16 In some embodiments, the plurality of tabs 13 include a first tab group 13a and a second tab group 13b. The plurality of electrode windings containing the first tab group 13a are located outside at least one electrode winding containing the second tab group 13b.

[0212] In the extension direction of the winding shaft CL, the minimum height h1 of the first tab group 13a in its unbent state is greater than the maximum height h2 of the second tab group 13b in its unbent state. By making the maximum height h2 of the second tab group 13b located inside the first tab group 13a smaller than the minimum height h1 of the first tab group 13a, the first tab 131 connected to the welding area 30 can be closer to the winding start end WS, which helps to reduce the risk of overcurrent in the first tab 131. Moreover, the smaller tab height of the first tab group 13a can reduce or avoid covering the center hole 110, effectively avoiding the impact of the tab blocking the center hole 110 on electrolyte injection.

[0213] refer to Figure 15 and Figure 16 The second electrode assembly 13b includes the first electrode 131, and in the extending direction of the winding shaft CL, the height h2 of the unbent second electrode assembly 13b decreases towards the direction closer to the winding shaft CL. Figure 15 In the middle, the height of the tabs in the second tab group 13b gradually decreases along the direction close to the winding axis CL, thus making Figure 16 The first tab 131 is closer to the winding shaft CL, thereby expanding the range of the second tab stacking region 130b.

[0214] By decreasing the height of each loop of the first tab group 13a from the outside to the inside, the second tab stacking area 130b can extend further toward the winding shaft CL, thereby increasing the range of the second tab stacking area 130b. This, in turn, helps to increase the size of the welding area 30 in the first part 31 of the second tab stacking area 130b, improve the welding quality of the welding area 30, and reduce the risk of tab burn-through or incomplete welding.

[0215] Based on the various embodiments of the battery cells described above, this disclosure also provides embodiments of batteries employing the aforementioned battery cell embodiments. The battery includes the battery cells of any of the aforementioned embodiments. Batteries employing the aforementioned battery cell embodiments offer superior safety in use.

[0216] In one aspect of this disclosure, an electrical device is provided, including the aforementioned battery. The electrical device employing the aforementioned battery offers superior safety in use.

[0217] While this disclosure has been described with reference to preferred embodiments, various modifications can be made thereto and components can be replaced with equivalents without departing from the scope of this disclosure. In particular, the technical features mentioned in the various embodiments can be combined in any manner, provided there is no structural conflict. This disclosure is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A battery cell (40), comprising: An electrode assembly (10) includes a plurality of electrode sheets (10a, 10b) and a spacer (10c) located between adjacent electrode sheets (10a, 10b) of opposite polarity. The plurality of electrode sheets (10a, 10b) and the spacer (10c) are wound along a winding direction (wd) to form a wound structure (100). At least one of the plurality of electrode sheets (10a, 10b) includes a current collector substrate (11) and a plurality of tabs (13). An active material layer (12) covering at least one side surface of the current collector substrate (11), the plurality of tabs (13) are connected to at least one side of the current collector substrate (11) extending along the winding direction (wd) and are spaced apart along the winding direction (wd), at least a portion of the plurality of tabs (13) are bent toward the winding axis (CL) of the winding structure (100) and a tab stack structure (130) is formed at the end of the winding structure (100). The housing (4A) has a chamber for accommodating the electrode assembly (10); Electrode terminals (42) are disposed on the wall of the housing (4A); and Conductive elements (21, 22) are welded to the tab stack structure (130) and electrically connected to the electrode terminal (42); The electrode stacking structure (130) includes a first electrode stacking region (130a) and a second electrode stacking region (130b) arranged from the outside to the inside along the direction close to the winding shaft (CL). The number of electrode stacking layers in the first electrode stacking region (130a) increases along the direction close to the winding shaft (CL), and the number of electrode stacking layers in the second electrode stacking region (130b) is equal along the direction close to the winding shaft (CL). The welding area (30) of the conductive element (21, 22) and the electrode stacking structure (130) includes a first part located in the second electrode stacking region (130b) and a second part (32) located in the first electrode stacking region (130a).

2. The battery cell (40) according to claim 1, wherein the tab stack structure (130) further comprises a third tab stack region (130c) located on the side of the second tab stack region (130b) adjacent to the winding shaft (CL), and the welding region (30) further comprises a third portion (33) located in the third tab stack region (130c).

3. The battery cell (40) according to any one of claims 1 to 2, wherein the ratio S1 / S of the area S1 of the first portion (31) to the area S of the welding region (30) satisfies: S1 / S≥70%.

4. The battery cell (40) according to claim 3, wherein the ratio S1 / S of the area S1 of the first portion (31) to the area S of the welding region (30) satisfies: S1 / S≥90%.

5. The battery cell (40) according to claim 1, wherein the winding structure (100) is a cylindrical winding structure, and the ratio L1 / L of the maximum radial length L1 of the first part (31) in the radial direction of the cylindrical winding structure to the maximum radial length L of the welding area (30) in the radial direction of the cylindrical winding structure satisfies: L1 / L≥70%.

6. The battery cell (40) according to claim 5, wherein the ratio L1 / L of the maximum radial length L1 of the first portion (31) in the radial direction of the cylindrical winding structure to the maximum radial length L of the welding area (30) in the radial direction of the cylindrical winding structure satisfies: L1 / L≥90%.

7. The battery cell (40) according to claim 1, wherein the minimum distance d between the winding start end (WS) of the current collector substrate (11) in the winding direction (wd) and the second tab (132) satisfies: d≤1200mm; in, The second tab (132) is defined as the tab among the plurality of tabs (13) that is welded to the conductive element (21, 22) and is closest to the winding start end (WS).

8. The battery cell (40) according to claim 7, wherein the minimum distance d satisfies: d≤800mm.

9. The battery cell (40) according to claim 1, wherein in the extension direction of the winding shaft (CL), the maximum value Hmax of the depth H of the welding area (30) of the conductive element (21, 22) and the tab stack structure (130) and the thickness t of the conductive element (21, 22) satisfy: 1.5*t≤Hmax≤1.9*t.

10. The battery cell (40) according to claim 9, wherein the maximum value Hmax of the depth H of the welding area (30) and the thickness t of the conductive element (21, 22) in the extension direction of the winding shaft (CL) satisfy: 1.6*t≤Hmax≤1.8*t.

11. The battery cell (40) according to claim 1, wherein in the extension direction of the winding shaft (CL), the minimum value Hmin of the depth H of the welding area (30) of the conductive element (21, 22) and the tab stack structure (130) and the thickness t of the conductive element (21, 22) satisfy: 1.1*t≤Hmin≤1.5*t.

12. The battery cell (40) according to claim 11, wherein the minimum value Hmin of the depth H of the welding area (30) and the thickness t of the conductive element (21, 22) in the extension direction of the winding shaft (CL) satisfy: 1.2*t≤Hmin≤1.4*t.

13. The battery cell (40) according to claim 1, wherein the difference between the maximum value Hmax and the minimum value Hmin of the depth H of the welding area (30) of the conductive element (21, 22) and the tab stack structure (130) in the extension direction of the winding shaft (CL) and the thickness t of the conductive element (21, 22) satisfy: 0.2*t≤(Hmax-Hmin)≤0.8*t.

14. The battery cell (40) according to claim 13, wherein the difference between the maximum value Hmax and the minimum value Hmin of the depth H of the welding area (30) (Hmax-Hmin) and the thickness t of the conductive element (21, 22) in the extension direction of the winding shaft (CL) satisfy: 0.3*t≤(Hmax-Hmin)≤0.6*t.

15. The battery cell (40) according to claim 1, wherein, in the winding direction (wd), the top spacing e of adjacent tabs in the plurality of tabs (13) satisfies: e≤0.5mm.

16. The battery cell (40) according to claim 15, wherein, in the winding direction (wd), the top spacing e of adjacent tabs in the plurality of tabs (13) satisfies: e≤0.2mm.

17. The battery cell (40) according to claim 1, wherein the welding area (30) of the conductive elements (21, 22) and the tab stack structure (130) includes a first portion located in the second tab stack area (130b), wherein the depth of the first portion (31) increases in the direction of extension of the winding shaft (CL) toward the winding shaft (CL).

18. The battery cell (40) according to claim 1, wherein the welding area (30) of the conductive element (21, 22) and the tab stack structure (130) includes a first portion located in the second tab stack area (130b) and a second portion (32) located in the first tab stack area (130a), wherein the depth of the first portion (31) is less than the depth of the second portion (32) in the extension direction of the winding shaft (CL).

19. The battery cell (40) according to claim 1, wherein at least a portion of the plurality of tabs (13) is rectangular or parallelogram-shaped.

20. The battery cell (40) according to claim 1, wherein the winding structure (100) is a cylindrical winding structure, the cylindrical winding structure having a central hole (110), and the minimum distance r1 between the winding shaft (CL) and the root of the first tab (131) satisfies: r1≥h0+0.8*R; in, h0 is the height of the first electrode in its unbent state in the extension direction of the winding shaft (CL), and R is the radius of the cross-section of the central hole (110) at the end of the winding structure (100).

21. The battery cell (40) according to claim 20, wherein the minimum distance r1 between the winding shaft (CL) and the root of the first tab (131) satisfies: r1≥h0+R.

22. The battery cell (40) according to claim 1, wherein the plurality of tabs (13) includes a first tab group (13a) and a second tab group (13b), wherein the plurality of electrode windings of the first tab group (13a) are located outside at least one electrode winding of the second tab group (13b), and in the extension direction of the winding shaft (CL), the minimum height h1 of the first tab group (13a) in the unbent state is greater than the maximum height h2 of the second tab group (13b) in the unbent state.

23. The battery cell (40) according to claim 22, wherein the second tab assembly (13b) includes the first tab (131), and the height h2 of the second tab assembly (13b) in its unbent state decreases toward the direction of the winding shaft (CL) in the extension direction of the winding shaft (CL).

24. The battery cell (40) according to claim 1, wherein the housing (4A) comprises a housing (41) and an end cap (42), one end of the housing (41) having an opening (411), the end cap (42) covering the opening (411), the housing (41) comprising a side wall (414) and a bottom wall (413), the side wall (414) surrounding the outside of the electrode assembly (10), the bottom wall (413) being disposed opposite to the opening (411), and the wall portion of the housing (4A) being the end cap (42) or the bottom wall (413).

25. A battery (50), comprising: The battery cell (40) according to any one of claims 1 to 24.

26. An electrical appliance, comprising: The battery (50) according to claim 25.

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