Battery monomer, battery and electric equipment

Abstract

The invention discloses a battery monomer, a battery and electric equipment. The battery cell (40) comprises: an electrode assembly (10) comprising a plurality of pole pieces (10a, 10b) and a separator (10c) arranged between adjacent pole pieces (10a, 10b) having opposite polarities among the plurality of pole pieces (10a, 10b), the plurality of pole pieces (10a, 10b) and the separator (10c) being wound in a winding direction (wd) and forming a wound structure (100), at least one of the plurality of pole pieces (10a, 10b) comprising a current collector substrate (11) and a plurality of tabs (13), the plurality of tabs (13) are connected with at least one side edge, extending along the winding direction (wd), of the current collector base material (11) and are arranged at intervals along the winding direction (wd), at least parts of the plurality of tabs (13) are bent towards the direction close to a winding shaft (CL) of the winding structure (100), and a tab stacking structure (130) is formed at the end part of the winding structure (100); a case (4A) having a chamber for accommodating the electrode assembly (10); an electrode terminal (42) provided on a wall portion of the case (4A); and the conductive parts (21 and 22) are welded with the tab stacking structure (130) and are electrically connected with the electrode terminal (42).

Description

Battery cells, batteries and electrical equipment Technical Field

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

[0002] Secondary batteries, especially lithium-ion batteries, offer advantages such as high voltage, high specific energy, long cycle life, environmental friendliness, a wide operating temperature range, and low self-discharge. They are widely used in portable electronic devices and powering large electric vehicles, playing a significant role in addressing environmental pollution and the energy crisis. With the widespread use of lithium-ion batteries, battery safety has become a matter of close concern to users.

[0003] Summary of the Invention

[0004] In one aspect of the present disclosure, there is provided a battery cell comprising:

[0005] An electrode assembly, comprising a plurality of electrode sheets and separators disposed between adjacent electrode sheets of opposite polarity among the plurality of electrode sheets, the plurality of electrode sheets and the separators being wound along a winding direction to form a wound structure, wherein at least one of the plurality of electrode sheets comprises a current collector substrate and a plurality of electrode tabs, the plurality of electrode tabs being connected to at least one side of the current collector substrate extending along the winding direction and spaced apart along the winding direction, at least portions of the plurality of electrode tabs being bent in a direction close to a winding axis of the wound structure to form a electrode tab stacking structure at an end of the wound structure;

[0006] a housing having a chamber for accommodating the electrode assembly;

[0007] an electrode terminal provided on a wall portion of the housing; and

[0008] A conductive member is welded to the tab stacking structure and electrically connected to the electrode terminal.

[0009] The conductive parts are electrically connected to the electrode terminals arranged on the wall of the shell, and are welded to the multiple tabs stacked at the end of the winding structure of the electrode assembly. The stacked multi-layer tab structure has a higher thickness and is not easily penetrated when welded with the conductive parts, so as to avoid the risk of burning the diaphragm or pole piece in the electrode assembly during welding, resulting in short circuit and other risks. This improves the welding quality of the welding area while reducing the short circuit risk of the battery cell and improving the safety of use.

[0010] In some embodiments, the tab stacking structure includes a first tab stacking area and a second tab stacking area arranged from the outside to the inside along a direction close to the winding axis. The number of tab stacking layers in the first tab stacking area increases along the direction close to the winding axis, and the number of tab stacking layers in the second tab stacking area is equal along the direction close to the winding axis. At least a portion of the welding area between the conductive member and the tab stacking structure is located in the second tab stacking area.

[0011] The number of tab stacking layers in the second tab stacking area is equal along the direction close to the winding axis. Therefore, when the conductive part is welded to the tab stacking structure formed at the end of the winding structure, the second tab stacking area has more tab stacking layers and a higher stacking thickness than other tab stacking areas. Therefore, it is not easy to be welded through when welding with the conductive part, thereby improving the welding quality of the welding area and reducing the risk of short circuit caused by burns on the diaphragm or electrode during welding.

[0012] In some embodiments, the welding region includes a first portion located in the second tab stacking region and a second portion located in the first tab stacking region.

[0013] By welding the second tab stacking area and the first tab stacking area to the conductive member through the first and second parts of the welding area respectively, the overall size of the welding area can be increased, thereby improving the welding strength and reducing the resistance of the welding area, thereby reducing the risk of overcurrent.

[0014] In some embodiments, the tab stacking structure further includes a third tab stacking region located on a side of the second tab stacking region adjacent to the winding axis, and the welding region further includes a third portion located in the third tab stacking region.

[0015] By welding the third tab stacking area to the conductive member, the overall size of the welding area can be increased, thereby improving the welding strength and reducing the resistance of the welding area, thereby reducing the risk of overcurrent.

[0016] In some embodiments, a ratio S1 / S of the area S1 of the first portion to the area S of the welding region satisfies: S1 / S ≥ 70%.

[0017] By making the ratio S1 / S greater than or equal to 70%, the welding quality of the welding area can be improved and the risk of tab welding through or cold welding can be reduced.

[0018] In some embodiments, a ratio S1 / S of the area S1 of the first portion to the area S of the welding region satisfies: S1 / S ≥ 90%.

[0019] By further limiting the ratio S1 / S to be greater than or equal to 90%, the welding quality of the welding area can be further improved, and the risk of tab welding through or cold welding can be effectively reduced.

[0020] In some embodiments, the winding structure is a cylindrical winding structure, and a ratio L1 / L of a maximum radial length L1 of the first portion in the radial direction of the cylindrical winding structure to a maximum radial length L of the welding area in the radial direction of the cylindrical winding structure satisfies: L1 / L≥70%.

[0021] By making the ratio L1 / L greater than or equal to 70%, the welding quality of the welding area can be improved and the risk of tab welding through or cold welding can be reduced.

[0022] In some embodiments, a ratio L1 / L of a maximum radial length L1 of the first portion in the radial direction of the cylindrical wound structure to a maximum radial length L of the welding region in the radial direction of the cylindrical wound structure satisfies: L1 / L ≥ 90%.

[0023] By further limiting the ratio L1 / L to be greater than or equal to 90%, the welding quality of the welding area can be further improved, and the risk of tab welding through or cold welding can be effectively reduced.

[0024] In some embodiments, the minimum distance d between the winding starting end of the current collector substrate and the second electrode tab in the winding direction satisfies: d≤1200 mm;

[0025] The second electrode tab is defined as the electrode tab welded to the conductive member and closest to the winding starting end among the plurality of electrode tabs.

[0026] By making the minimum distance d less than or equal to 1200 mm, the range of the tabs directly connected to the conductive parts through the welding area can be increased, and the risk of overcurrent in the second tab can be reduced, thereby minimizing the tab overheating and affecting the performance of the chemical substances in the electrode assembly.

[0027] In some embodiments, the minimum distance d satisfies: d≤800 mm.

[0028] By further limiting the minimum distance d to less than or equal to 800 mm, the range of the tabs directly connected to the conductive parts through the welding area can be increased to a greater extent, further reducing the risk of overcurrent in the first tab, thereby more effectively avoiding overheating of the tabs and affecting the performance of the chemical substances in the electrode assembly.

[0029] In some embodiments, in the extension direction of the winding axis, the maximum value Hmax of the depth H of the welding region between the conductive member and the tab stacking structure and the thickness t of the conductive member satisfy: 1.5*t≤Hmax≤1.9*t.

[0030] By setting a specific range of the ratio of the maximum value Hmax of the depth of the welding area to the thickness t of the conductive member, the risk of tab welding through and cold welding can be reduced as much as possible.

[0031] In some embodiments, in the extension direction of the winding axis, the maximum value Hmax of the depth H of the welding region and the thickness t of the conductive member satisfy: 1.6*t≤Hmax≤1.8*t.

[0032] By further limiting the optional range of the ratio of the maximum value Hmax of the depth of the welding area to the thickness t of the conductive member, the risks of tab welding through and cold welding can be effectively reduced.

[0033] In some embodiments, in the extension direction of the winding axis, a minimum value Hmin of a depth H of a welding region between the conductive member and the tab stack structure and a thickness t of the conductive member satisfy: 1.1*t≤Hmin≤1.5*t.

[0034] By setting a specific range of the ratio of the minimum depth Hmin of the welding area to the thickness t of the conductive member, the risk of tab welding through and cold welding can be reduced as much as possible.

[0035] In some embodiments, in the extension direction of the winding axis, the minimum value Hmin of the depth H of the welding region and the thickness t of the conductive member satisfy: 1.2*t≤Hmin≤1.4*t.

[0036] By further limiting the optional range of the ratio of the minimum value Hmin of the depth of the welding area to the thickness t of the conductive member, the risks of tab welding through and cold welding can be effectively reduced.

[0037] In some embodiments, in the extension direction of the winding axis, the difference (Hmax-Hmin) between the maximum value Hmax and the minimum value Hmin of the depth H of the welding area of ​​the conductive part and the tab stacking structure and the thickness t of the conductive part satisfy: 0.2*t≤(Hmax-Hmin)≤0.8*t.

[0038] By limiting the ratio of the difference (Hmax-Hmin) to the thickness t of the conductive member to a specific range, the risk of local welding through or cold welding of the tab can be reduced.

[0039] In some embodiments, in the extension direction of the winding axis, the difference (Hmax-Hmin) between the maximum value Hmax and the minimum value Hmin of the depth H of the welding area and the thickness t of the conductive member satisfy: 0.3*t≤(Hmax-Hmin)≤0.6*t.

[0040] By further limiting the optional range of the ratio of the difference (Hmax-Hmin) to the thickness t, the risk of local welding penetration or cold welding of the tab can be further reduced.

[0041] In some embodiments, in the winding direction, a top spacing e between adjacent tabs in the plurality of tabs satisfies: e≤0.5 mm.

[0042] By making the top spacing e between adjacent tabs less than or equal to 0.5 mm, the tab stacking degree can be increased, thereby obtaining a larger tab stacking thickness and reducing the risk of tab welding penetration.

[0043] In some embodiments, in the winding direction, a top spacing e between adjacent tabs in the plurality of tabs satisfies: e≤0.2 mm.

[0044] By further limiting the tab top spacing e 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 welding through.

[0045] In some embodiments, the welding region between the conductive member and the tab stacking structure includes a first portion located in the second tab stacking region, and in the extending direction of the winding axis, the depth of the first portion increases in a direction approaching the winding axis.

[0046] Since the curvature of the pole piece winding layer is greater as it is closer to the winding axis, the connected pole tabs overlap more, so that the thickness of the pole tab stack gradually increases from the outside to the inside. This allows the welding power to gradually increase from the outside to the inside, forming a welding area with increasing depth from the outside to the inside, thereby improving the welding quality of the welding area.

[0047] In some embodiments, the welding area between the conductive member and the tab stacking structure includes a first portion located in the second tab stacking area and a second portion located in the first tab stacking area, and in the extension direction of the winding axis, the depth of the first portion is less than the depth of the second portion.

[0048] Considering that the number of tab stacking layers in the first tab stacking area is relatively small and the molten pool depth is relatively small without welding through, the welding power used when welding in the first tab stacking area can be lower than the welding power used when welding in the second tab stacking area, thereby improving the welding quality of the second part of the first tab stacking area and reducing the risk of tab welding through.

[0049] In some embodiments, at least a portion of the plurality of tabs are rectangular or parallelogram-shaped.

[0050] Considering that rectangular or parallelogram-shaped tabs can achieve smaller tab top spacing, it is beneficial to increase the overlap of adjacent tabs, thereby increasing the thickness of the tab stack and reducing the risk of tab welding through.

[0051] In some embodiments, the winding structure is a cylindrical winding structure having a central hole, and a minimum distance r1 between the winding axis and the base of the first tab satisfies: r1≥h0+0.8*R;

[0052] Wherein, h0 is the height of the first electrode tab in an unbent state in the extension direction of the winding axis, and R is the radius of the hole cross section of the center 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 pole ear and 0.8 times the radius R of the center hole, which is equivalent to the first pole ear closest to the winding axis covering no more than 20% of the radius of the center hole after being bent from the outside to the inside, thereby reducing the obstruction of the center hole after the pole ear is bent, so as not to affect the injection of electrolyte, and reducing the risk of short circuit caused by the pole ear being inserted downward or torn during injection.

[0054] In some embodiments, a minimum distance r1 between the winding axis and the tab root of the first 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, which is equivalent to the first tab closest to the winding axis not covering the center hole after being bent from the outside to the inside, thereby more effectively avoiding the influence of the tab blocking the center hole on the electrolyte injection.

[0056] In some embodiments, the multiple pole tabs include a first pole tab group and a second pole tab group, the multiple pole piece windings of the first pole tab group are located on the outside of at least one pole piece winding of the second pole tab group, and in the extension direction of the winding axis, the minimum height h1 of the first pole tab group in the unbent state is greater than the maximum height h2 of the second pole tab group in the 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 made closer to the starting end of the winding, which is beneficial to reducing the risk of overcurrent in the first tab. In addition, 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 tab group includes the first electrode tab, and in the extending direction of the winding axis, a height h2 of the second electrode tab group in an unbent state decreases toward the direction approaching the winding axis.

[0059] By decreasing the height of each ring of the tabs in the first tab group from the outside to the inside, the second tab stacking area can be extended more toward the winding axis, thereby increasing the range of the second tab stacking area, which is beneficial to increasing the size of the first part of the welding area in the second tab stacking area, improving the welding quality of the welding area, and reducing the risk of tab welding through or cold welding.

[0060] In some embodiments, the shell includes a shell and an end cover, one end of the shell has an opening, the end cover covers the opening, the shell includes a side wall and a bottom wall, the side wall surrounds the outside of the electrode assembly, the bottom wall is arranged opposite to the opening, and the wall portion of the shell is the end cover or the bottom wall.

[0061] The conductive member is electrically connected to the electrode terminal provided on the end cover or the bottom wall of the shell, and is welded to the tab stacking structure of the electrode assembly, which improves the welding quality of the welding area, reduces the short circuit risk of the battery cell, and improves the safety of use.

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

[0063] In one aspect of the present disclosure, an electrical device is provided, comprising the aforementioned battery. The electrical device using the aforementioned battery can effectively improve safety in use. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the following briefly introduces the drawings required for use in the embodiments of the present disclosure. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on the drawings without any creative work.

[0065] The present disclosure can be more clearly understood from the following detailed description with reference to the accompanying drawings, in which:

[0066] FIG1 is a schematic structural diagram of some embodiments of an electric device according to the present disclosure;

[0067] FIG2 is an exploded schematic diagram of some embodiments of batteries according to the present disclosure;

[0068] FIG3 is a schematic diagram of the connection of multiple battery cells in some embodiments of the battery according to the present disclosure;

[0069] FIG4A is an exploded schematic diagram of some embodiments of a battery cell according to the present disclosure;

[0070] FIG4B is a schematic longitudinal cross-sectional view of a battery cell according to some embodiments of the present disclosure through a winding axis;

[0071] FIG4C is an exploded schematic diagram of an electrode assembly and a conductive member in some embodiments of a battery cell according to the present disclosure;

[0072] FIG5 is a schematic cross-sectional view of a wound structure in some embodiments of a battery cell according to the present disclosure;

[0073] FIG6 is a schematic diagram of a pole piece and a pole tab in an unfolded state according to some embodiments of a battery cell of the present disclosure;

[0074] FIG7 is a schematic cross-sectional view of the structure of welding the tab stacking structure and the conductive member according to some embodiments of the battery cell of the present disclosure;

[0075] FIG8 is a cross-sectional schematic diagram of multiple tab stacking regions of a tab stacking structure according to some embodiments of a battery cell of the present disclosure;

[0076] FIG9 is a schematic diagram showing the distribution of welding areas in multiple tab stacking areas of a tab stacking structure according to some embodiments of a battery cell of the present disclosure;

[0077] FIG10 is a schematic diagram showing the dimensions of various parts of a welding area in some embodiments of a battery cell according to the present disclosure;

[0078] FIG11 is a schematic diagram of overlapping adjacent tabs in different tab stacking regions in some embodiments of a battery cell according to the present disclosure;

[0079] FIG12 and FIG13 are schematic diagrams showing the dimensions of tabs of different shapes connected to pole pieces according to some embodiments of the battery cell disclosed herein;

[0080] FIG14 is a schematic diagram showing the dimensions of a bent tab and a central hole in some embodiments of a battery cell according to the present disclosure;

[0081] FIG15 is a schematic diagram showing the height of the tabs in an unbent state according to other embodiments of the battery cell of the present disclosure;

[0082] FIG16 is a cross-sectional schematic diagram of a stacked region of multiple tabs after the tabs are bent toward the center hole in FIG15 .

[0083] It should be understood that the size of each part shown in the drawings is not drawn according to the actual proportional relationship.In addition, the same or similar reference numerals represent the same or similar components.

[0084] Explanation of Reference Numerals: 10 - electrode assembly; 10a - first pole piece; 10b - second pole piece; 10c - separator; 100 - winding structure; 110 - center hole; 11 - current collector substrate; 12 - active material layer; 13 - tab; 130 - tab stacking structure; 130a - first tab stacking region; 130b - second tab stacking region; 130c - third tab stacking region; 131 - first tab; 132 - second tab; 13a - first tab group; 13b - second tab group; 21, 22 - conductive member; 30 - welding region; 31 - first portion; 32 - second portion; 33 - third portion; 40 - battery cell; 4A - housing; 41 - casing; 411 - opening; 412 - through hole; 42 - end cap; 421 - pressure relief component; 43 - electrode terminal; 44 - insulator; 45 - electrode lead-out portion; 46 - bus bar; 50 - battery; 51 - housing; 52 - housing cover; 60 - vehicle; wd - winding direction; CL - winding axis; WS - winding start end. DETAILED DESCRIPTION

[0085] The following detailed description of the embodiments of the present disclosure is provided in conjunction with the accompanying drawings and examples. The detailed description of the following embodiments and the accompanying drawings are used to illustrate the principles of the present disclosure, but are not intended to limit the scope of the present disclosure, that is, the present disclosure is not limited to the described embodiments.

[0086] In the description of the present disclosure, it should be noted that, unless otherwise specified, "multiple" means more than two; the terms "upper", "lower", "left", "right", "inside", "outside", etc., indicating directions or positional relationships, are only for the convenience of describing the present disclosure and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present disclosure. In addition, the terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. "Vertical" is not strictly perpendicular, but is within the allowable error range. "Parallel" is not strictly parallel, but is within the allowable error range.

[0087] The directional words appearing in the following description are all directions shown in the figures and do not limit the specific structure of the present disclosure. In the description of the present disclosure, it should also be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present disclosure can be understood according to the specific circumstances.

[0088] The following describes some embodiments of the present invention in detail with reference to the accompanying drawings. In the absence of conflict, the features of the following embodiments can be combined with each other.

[0089] The term "plurality" appearing in the present disclosure refers to two or more (including two).

[0090] In the embodiment of the present disclosure, the battery cell may be a secondary battery. A secondary battery refers to a battery cell that can be continuously used by activating active materials by charging after the battery cell is discharged.

[0091] The battery cells can be lithium-ion batteries, sodium-ion batteries, sodium-lithium-ion batteries, lithium metal batteries, sodium metal batteries, lithium-sulfur batteries, magnesium-ion batteries, nickel-hydrogen batteries, nickel-cadmium batteries, lead-acid batteries, etc., which are not limited in the embodiments of the present application.

[0092] A battery cell generally includes an electrode assembly. The electrode assembly includes multiple electrode sheets and separators disposed between adjacent electrode sheets. The multiple electrode sheets may include positive and negative electrode sheets of opposite polarity. During the charge and discharge process of the battery cell, active ions (such as lithium ions) are embedded in and released from the positive and negative electrode sheets. The separator is disposed between the positive and negative electrode sheets to prevent short circuits between the positive and negative electrodes while allowing active ions to pass through.

[0093] In some embodiments, the positive electrode sheet may include a positive electrode current collector substrate and a positive electrode active material layer disposed on at least one surface of the positive electrode current collector substrate.

[0094] As an example, the positive electrode current collector substrate has two surfaces facing each other in its thickness direction, and the positive electrode active material layer is provided on either or both of the two facing surfaces of the positive electrode current collector substrate.

[0095] As an example, the positive electrode current collector substrate can be a metal foil or a composite current collector. For example, as the metal foil, aluminum or stainless steel with a silver surface treatment, stainless steel, copper, aluminum, nickel, carbon electrode, 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 placing a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0096] As an example, the positive electrode active material layer may include at least one of the following materials: lithium-containing phosphates, lithium transition metal oxides and their respective modified compounds. However, the present disclosure is not limited to these materials, and other traditional materials that can be used as battery positive electrode active material layers may also be used. These positive electrode active material layers may be used alone or in combination of two or more. Among them, examples of lithium-containing phosphates may include but are not limited to at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO4), a composite material of lithium manganese phosphate and carbon, lithium iron manganese phosphate, and a composite material of lithium iron manganese phosphate and carbon. Examples of lithium transition metal oxides may 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, lithium nickel cobalt manganese oxide (such as LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also referred to as NCM 333 ), LiNi 0.5 Co 0.2 Mn 0.3 O2 (also referred to as NCM 523 ), LiNi 0.5 Co 0.25 Mn 0.25 O2 (also referred to as NCM 211 ), LiNi 0.6 Co 0.2 Mn 0.2 O2 (also referred to as NCM 622 ), LiNi 0.8 Co 0.1 Mn 0.1 O2 (also referred to as NCM 811 ), lithium nickel cobalt aluminum oxide (such as LiNi 0.85 Co 0.15 Al 0.05 O2) and at least one of its modified compounds, etc.

[0097] In some embodiments, the negative electrode sheet may include a negative electrode current collector substrate.

[0098] 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 the metal foil, aluminum or stainless steel treated with silver, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel, or titanium can be used. The foamed metal can be nickel foam, copper foam, aluminum foam, alloy foam, or carbon foam. The composite current collector can include a polymer material base layer and a metal layer. The composite current collector can be formed by placing a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0099] 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.

[0100] As an example, the negative electrode current collector substrate has two surfaces facing each other in its thickness direction, and the negative electrode active material layer is provided on either or both of the two facing surfaces of the negative electrode current collector substrate.

[0101] As an example, the negative electrode active material layer may adopt the negative electrode active material layer for battery cells that is well known in the art. 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, lithium titanate, etc. The silicon-based material may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. The tin-based material may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, the present disclosure is not limited to these materials, and other traditional materials that can be used as negative electrode active material layers for batteries may also be used. These negative electrode active material layers may be used alone or in combination of two or more.

[0102] In some embodiments, the material of the positive electrode current collector substrate may be aluminum, and the material of the negative electrode current collector substrate may be copper.

[0103] In some embodiments, the electrode assembly further includes a separator disposed between the positive electrode and the negative electrode.

[0104] In some embodiments, the separator is a separator. The present disclosure has no particular limitation on the type of separator, and any known separator with a porous structure having good chemical stability and mechanical stability can be selected.

[0105] As an example, the primary 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 positioned between the positive and negative electrode sheets, or it can be attached to the surface of the positive and / or negative electrode sheets.

[0106] In some embodiments, the separator is a solid electrolyte, which is disposed between the positive electrode and the negative electrode, and serves to transport ions and isolate the positive and negative electrodes.

[0107] In some embodiments, the battery cell further includes an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. This disclosure does not specifically limit the type of electrolyte, and the electrolyte may be selected based on needs. The electrolyte may be liquid, gel, or solid.

[0108] As an example, the liquid electrolyte includes an electrolyte salt and a solvent.

[0109] 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 difluorooxalatoborate, lithium dioxalatoborate, lithium difluorodioxalatophosphate, and lithium tetrafluorooxalatophosphate.

[0110] In some embodiments, the solvent can be selected from at least one of ethylene carbonate, propylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methylpropyl carbonate, ethylpropyl carbonate, butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, cyclopentane, dimethyl sulfone, methyl ethyl sulfone and diethyl sulfone. The solvent can also be an ether solvent. Ether solvents can 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, methyltetrahydrofuran, diphenyl ether and crown ether.

[0111] As an example, a gel electrolyte includes a polymer as an electrolyte skeleton network, combined with an ionic liquid-lithium salt.

[0112] As examples, the solid electrolyte includes a polymer solid electrolyte, an inorganic solid electrolyte, and a composite solid electrolyte.

[0113] As an example, the polymer solid electrolyte may be polyether (polyethylene oxide), polysiloxane, polycarbonate, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, a single ion polymer, polyionic liquid-lithium salt, cellulose, or the like.

[0114] As an example, the inorganic solid electrolyte can be an oxide solid electrolyte (crystalline perovskite, sodium superconducting ion conductor, garnet, amorphous LiPON film), a sulfide solid electrolyte (crystalline lithium superion conductor (lithium germanium phosphide, germanium silver sulfide), amorphous sulfide) and one or more of a halide solid electrolyte, a nitride solid electrolyte and a hydride solid electrolyte.

[0115] As an example, a composite solid electrolyte is formed by adding an inorganic solid electrolyte filler to a polymer solid electrolyte.

[0116] In some embodiments, the electrode assembly includes a wound structure in which the positive electrode sheet, the negative electrode sheet, and the separator are wound into the wound structure.

[0117] As an example, one or more positive electrode sheets and one or more negative electrode sheets may be provided respectively, and multiple positive electrode sheets and multiple negative electrode sheets may be alternately stacked.

[0118] As an example, multiple positive electrode sheets may be provided, and the negative electrode sheet is folded to form multiple stacked folded segments, with a positive electrode sheet sandwiched between adjacent folded segments.

[0119] As an example, both the positive electrode sheet and the negative electrode sheet are folded to form a plurality of stacked folded segments.

[0120] As an example, multiple separators may be provided, each of which is provided between any adjacent positive electrode sheets or negative electrode sheets.

[0121] As an example, the separator may be provided continuously, and may be provided between any adjacent positive electrode sheets or negative electrode sheets by folding or winding.

[0122] In some embodiments, the shape of the electrode assembly can be cylindrical, flat, or polygonal.

[0123] In some embodiments, the electrode assembly includes tabs that conduct current from the electrode assembly. These tabs include positive and negative tabs, which are connected to the positive and negative current collector substrates, respectively. The tabs can be formed by cutting or trimming the current collector substrate, or by welding them to the sides of the current collector substrate.

[0124] In some embodiments, a battery cell may include a housing. The housing is used to encapsulate components such as the electrode assembly and the electrolyte. The housing may be a steel housing, an aluminum housing, a plastic housing (e.g., polypropylene), a composite metal housing (e.g., a copper-aluminum composite housing), or an aluminum-plastic film.

[0125] As an example, the battery cell can be a cylindrical battery cell, a prismatic battery cell, a soft-pack battery cell or a battery cell of other shapes. The prismatic battery cell includes a square-shell battery cell, a blade-shaped battery cell, a polygonal battery, such as a hexagonal battery, etc. There is no special limitation in the present disclosure.

[0126] The battery mentioned in the embodiments of the present disclosure refers to a single physical module including one or more battery cells to provide higher voltage and capacity.

[0127] In some embodiments, the battery may be a battery module. When there are multiple battery cells, the multiple battery cells are arranged and fixed to form a battery module. A battery module may include multiple battery cells connected in series, parallel, or hybrid.

[0128] In some embodiments, the battery may be a battery pack, which includes a case and battery cells, wherein the battery cells or battery modules are housed in the case.

[0129] In some embodiments, the box body can be used as a part of the chassis structure of the vehicle. For example, part of the box body can become at least a part of the floor of the vehicle, or part of the box body can become at least a part of the cross beam and longitudinal beam of the vehicle.

[0130] In some embodiments, the battery may be an energy storage device, including an energy storage container, an energy storage cabinet, and the like.

[0131] In some related battery cells, when welding the tabs at the ends of the electrode assemblies to the current collecting plates, there is a possibility of welding quality problems such as welding through the tabs or cold welding, thereby affecting the safety of the battery.

[0132] In view of this, embodiments of the present disclosure provide a battery cell, a battery, and an electrical device, which can improve the safety of battery use.

[0133] The battery cells of the disclosed embodiments are applicable to various types of batteries. A 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 in a hybrid configuration. A battery cell is the smallest unit of a battery. It includes an electrode assembly capable of undergoing an electrochemical reaction.

[0134] The battery of the embodiment of the present disclosure can be applied to various types of battery-using electrical equipment. Electrical equipment can be mobile phones, portable devices, laptop computers, battery cars, electric cars, ships, spacecraft, electric toys and electric tools, etc. For example, spacecraft include airplanes, rockets, space shuttles and spacecrafts, etc. Electric toys include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys and electric airplane toys, etc. Electric 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. The embodiment of the present disclosure does not impose any special restrictions on the above-mentioned electrical equipment. The battery can be used to power electrical equipment such as vehicles, for example, to provide power for vehicle control or power for driving.

[0135] Figure 1 is a schematic diagram of the structure of some embodiments of electrical devices according to the present disclosure. For convenience, the description uses a vehicle as an example. Vehicle 60 can be a fuel-powered vehicle, a gas-powered vehicle, or a new energy vehicle. The new energy vehicle can be a pure electric vehicle or a hybrid vehicle. A battery 50 can be installed at the bottom, front, or rear of vehicle 60.

[0136] The battery 50 can be used to power the vehicle 60. For example, the battery 50 can serve as the operating power source of the vehicle 60 and be used for the circuit system of the vehicle 60, such as the power requirements for starting, navigating, and operating the vehicle 60. The battery 50 can not only serve as the operating power source of the vehicle 60, but also as the driving power source of the vehicle 60, replacing or partially replacing fuel or natural gas to provide driving force for the vehicle 60.

[0137] Vehicle 60 may also be equipped with axles, wheels, a motor, and a controller. The controller is used to control the power supplied by battery 50 to the motor. For example, when vehicle 60 is powered by battery 50, battery 50 replaces or partially replaces fuel or natural gas to provide the motor with the power required for constant speed and acceleration. The motor is used to drive the axles, thereby driving the wheels.

[0138] Figure 2 is an exploded schematic diagram of some embodiments of the battery according to the present disclosure. Figure 3 is a schematic diagram of the connection of multiple battery cells in some embodiments of the battery according to the present disclosure.

[0139] 2 , in some embodiments, a battery 50 includes a housing 51, a cover 52 covering an open side of the housing 51, and one or more battery cells 40 disposed within the housing 51. The housing 51 and cover 52 provide space for the battery cells 40 and offer cooling, sealing, and impact protection functions. They also prevent liquids or other foreign matter from adversely affecting the charging, discharging, or safety of the battery cells.

[0140] The box body 51 and the box cover 52 can be of various shapes, such as a rectangular parallelepiped or a cylinder. The box body 51 can be a hollow structure with one side open, and the box cover 52 can be a plate-like structure. The box cover 52 covers the open side of the box body 51, thereby forming an internal storage space. In another embodiment, the box body 51 is a hollow structure with one side open, and the box cover 52 is also a hollow structure with one side open. The open side of the box cover 52 covers the open side of the box body 51, thereby forming an internal storage space.

[0141] Referring to Figures 2 and 3 , the battery cells 40 are electrically connected, such as in series, parallel, or hybrid, to achieve the desired electrical performance parameters of the battery 50. Hybrid means that multiple battery cells 40 are connected both in series and in parallel. Adjacent battery cells 40 can be electrically connected via busbars 44. Multiple battery cells 40 are arranged in rows, and one or more rows of battery cells 40 can be arranged within the housing as needed.

[0142] In some embodiments, the battery cells 40 of the battery 50 can be arranged along at least one of the length and width of the housing. Depending on actual needs, at least one row or column of battery cells 40 can be provided. Alternatively, one or more layers of battery cells 40 can be arranged along the height of the battery 50.

[0143] In some embodiments, multiple battery cells 40 may be connected in series, parallel, or hybrid to form a battery module, and then the multiple battery modules may be connected in series, parallel, or hybrid to form a whole unit, which is then housed in the housing 51. In other embodiments, all battery cells 40 may be directly connected in series, parallel, or hybrid to form a whole unit, and then all battery cells 40 may be housed in the housing.

[0144] Figure 4A is an exploded schematic diagram of some embodiments of a battery cell according to the present disclosure. Figure 4B is a schematic longitudinal cross-sectional view through a winding axis according to some embodiments of a battery cell according to the present disclosure. Figure 4C is an exploded schematic diagram of an electrode assembly and a conductive member according to some embodiments of a battery cell according to the present disclosure. Figure 5 is a schematic cross-sectional view of a winding structure according to some embodiments of a battery cell according to the present disclosure.

[0145] Referring to Figures 3 to 5 , in some embodiments, a battery cell 40 includes an electrode assembly 10, a housing 4A, electrode terminals 42, and conductive members 21 and 22. The electrode assembly 10 includes a plurality of electrode sheets 10a and 10b and a separator 10c disposed between adjacent electrode sheets 10a and 10b of opposite polarity. The plurality of electrode sheets 10a and 10b and the separator 10c are wound along a winding direction wd to form a wound structure 100.

[0146] In FIG5 , the plurality of electrode sheets may include electrode sheet 10a serving as a positive electrode sheet and electrode sheet 10b serving as a negative electrode sheet. The electrode sheet windings formed by electrode sheets 10a and electrode sheets 10b in the wound structure 100 are at least partially arranged alternately from the outside to the inside. Separator 10c may be provided between electrode sheets 10a and 10b in the form of a separator. In other embodiments, electrode sheet 10a may serve as a negative electrode sheet, and electrode sheet 10b may serve as a positive electrode sheet.

[0147] 4A and 4B , the housing 4A has a chamber for accommodating the electrode assembly 10. The electrode terminal 42 is provided on a wall of the housing 4A and is electrically connected to the conductive member 21. The electrode terminal 42 may be provided on a side wall or a bottom wall of the housing 4A.

[0148] The cavity of the housing 4A accommodates both the electrode assembly 10 and the electrolyte. The shape of the housing 4A can be determined according to the shape of the one or more electrode assemblies 10 accommodated in the cavity. For example, the shape of the housing 4A can be a hollow cuboid, a hollow cube, or a hollow cylinder.

[0149] Housing 4A may include a shell 41 and an end cap 42. Shell 41 is a hollow structure with an opening 411 at one or both ends. It may be made of one or more materials, such as copper, iron, aluminum, steel, aluminum alloy, plastic, etc. End cap 42 may be made of metal or non-metal and may be fixedly connected to shell 41 by welding, bonding, or fasteners.

[0150] Referring to Figure 4B , one end of the housing 41 has an opening 411, and an end cap 42 covers the opening 411. The housing 41 includes sidewalls 414 and a bottom wall 413. The sidewalls 414 surround the outside of the electrode assembly 10, and the bottom wall 413 is disposed opposite the opening 411. The wall portion of the outer shell 4A serves as the end cap 42 or the bottom wall 413. Accordingly, the electrode terminal 42 can be disposed on either the end cap 42 or the bottom wall 413.

[0151] For cylindrical battery cells, the shell 41 can be a cylindrical hollow structure with an opening 411 at one end, and the end cover 42 can be a disc-shaped structure that matches the opening 411. The electrode terminal 42 can be set on the bottom wall 413 of the shell 41 on the side away from the end cover 42. In Figures 4A and 4B, the bottom wall 413 is provided with a through hole 412, and the electrode terminal 42 can be set on the through hole 412 through the electrode lead-out portion 45 and the insulating member 42. The electrode lead-out portion 45 can at least partially protrude from the outer surface of the bottom wall 413 to facilitate electrical connection between different battery cells 40 through the bus bar 46. The insulating member 42 is used to achieve insulation between the electrode lead-out portion 45 and the shell 41, and can be made of rubber or plastic. Optionally, openings are provided at both ends of the shell, and both are covered by end covers, and the electrode lead-out portion and the electrode terminal can be provided on the end covers.

[0152] Referring to Figure 4A, a pressure relief component 421 can be provided on the end cover 42. The pressure relief component refers to an element or component that is actuated to release the internal pressure or temperature when the internal pressure or temperature of the battery cell reaches a predetermined threshold. The threshold design varies according to different design requirements. The threshold may depend on one or more materials of the positive electrode plate, negative electrode plate, electrolyte and isolation membrane in the battery cell. The pressure relief component can take the form of an explosion-proof valve, an air valve, a pressure relief valve or a safety valve, and can specifically adopt a pressure-sensitive or temperature-sensitive element or structure, that is, when the internal pressure or temperature of the battery cell reaches a predetermined threshold, the pressure relief component performs an action or the weak structure provided in the pressure relief component is destroyed, thereby forming an opening or channel for the internal pressure or temperature to be released.

[0153] The emissions from battery cells mentioned here include but are not limited to: electrolyte, dissolved or split positive and negative electrode plates, fragments of isolation membranes, high-temperature and high-pressure gases produced by the reaction (such as CH4, CO and other combustible gases), flames, etc.

[0154] 4A to 4C , the conductive members 21 and 22 may be located on both sides of the electrode assembly 10 along the extension direction of the winding axis of the wound structure 100, or may be located on one side of the electrode assembly 10 along the extension direction of the winding axis of the wound structure 100. In FIG4B , the conductive member 21 is welded to the tab at one end of the electrode assembly 100 and to the electrode lead-out portion 45, and the conductive member 22 is welded to the tab at the other end of the electrode assembly 100 and to the end cap 42. The conductive members 21 and 22 may serve as current collectors to achieve electrical connection between the electrode assembly and structures such as electrode terminals and end caps. The conductive member may be a metal conductor, such as copper, iron, aluminum, steel, aluminum alloy, etc. In some embodiments, the conductive member may include a current collecting disc or other structures.

[0155] Figure 6 is a schematic diagram of a tab and a tab in an unfolded state according to some embodiments of a battery cell according to the present disclosure. Figure 7 is a schematic cross-sectional diagram of a tab stacking structure welded to a conductive member according to some embodiments of a battery cell according to the present disclosure. Figure 8 is a schematic cross-sectional diagram of multiple tab stacking regions of a tab stacking structure according to some embodiments of a battery cell according to the present disclosure.

[0156] 6 , at least one of the plurality of electrode sheets of the electrode assembly 10 includes a current collector substrate 11 and a plurality of electrode tabs 13 . The electrode sheet may further include an active material layer 12 covering at least one side of the current collector substrate 11 .

[0157] 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. The plurality of tabs 13 may be connected to one side of the current collector substrate 11 extending along the winding direction wd, or may be connected to both sides of the current collector substrate 11 extending along the winding direction wd.

[0158] 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 .

[0159] Referring to FIG7 , at least a portion of the plurality of tabs 13 is bent toward the winding axis CL of the wound structure 100, forming a tab stack 130 at the end of the wound structure 100. The tab stack 130 can be electrically connected to the electrode terminal 42 provided on the wall of the housing 4A via conductive members 21 and 22 (e.g., a current collecting plate). Specifically, the conductive members 21 and 22 are welded to the tab stack 130.

[0160] The conductive parts 21 and 22 can form a continuous or discrete welding area 30 with the tab stacking structure 130. When the conductive parts 21 and 22 and the tab stacking structure 130 are welded by laser or other means, the welding area 30 appears as a liquid metal part that is heated and melted into a certain geometric shape, that is, a welding pool.

[0161] Referring to Figures 7 and 8 , the tab stacking structure 130 includes a first tab stacking region 130a and a second tab stacking region 130b arranged from the outside inward along a direction close to the winding axis CL. Figures 7 and 8 show partial cross-sections of the tabs connected to each winding turn of the pole piece after winding, bent toward the winding axis CL and stacked in sequence. The winding axis CL is depicted by a dotted line. For ease of illustration, the other pole pieces and separators in the winding structure are omitted in the figures.

[0162] The number of tab stacking layers in the first tab stacking region 130a increases in a direction approaching the winding axis CL. The number of tab stacking layers in the second tab stacking region 130b is equal in a direction approaching the winding axis CL. The number of tab stacking layers at a certain position here refers to the number of tab stacking layers connected by different pole piece windings of the tab stacking structure 130 at that position, that is, the number of pole piece windings corresponding to each tab stacked at that position.

[0163] Referring to Figure 8, in the first tab stacking region 130a, the further away from the winding axis CL, the fewer tab stacking layers there are. For tabs of substantially the same height, the number of stacked layers gradually increases from one outermost layer to more than ten layers. The location where the second tab stacking region 130b meets the first tab stacking region 130a is actually the point where the number of tab stacking layers in the first tab stacking region 130a no longer increases. The number of tab stacking layers at each location in the second tab stacking region 130b along the direction close to the winding axis CL remains the same.

[0164] Referring to Figure 6 , the first electrode tab 131 is defined as the tab closest to the winding start end WS of the current collector substrate among the multiple electrode tabs 13. To facilitate visualization of the first electrode tab 131, the electrode sheet in Figure 6 has been flattened; its length is aligned with the winding direction. The winding start end WS is the starting point of the electrode sheet winding and is located at the innermost side of the winding structure. Accordingly, the second electrode tab stacking region 130 may extend to the electrode sheet winding where the first electrode tab 131 is located.

[0165] Figure 9 is a schematic diagram illustrating the distribution of welding regions within multiple tab stacking regions of a tab stacking structure according to some embodiments of a battery cell of the present disclosure. Referring to Figure 9 , at least a portion of the welding region 30 between the conductive members 21 and 22 and the tab stacking structure 130 is located within the second tab stacking region 130b. In some embodiments, the entire welding region 30 is located within the second tab stacking region 103b. In other embodiments, a portion of the welding region 30 is located within the second tab stacking region 103b, while another portion is located within other portions of the tab stacking structure outside of the second tab stacking region 103b.

[0166] Since the number of tab stacking layers in the second tab stacking area 130b is equal, when the conductive members 21 and 22 are welded to the tab stacking structure 130 formed at the end of the winding structure 100, the second tab stacking area 130b has more tab stacking layers and a higher stacking thickness than other tab stacking areas, and is therefore not easily welded through when welding with the conductive members 21 and 22, thereby improving the welding quality of the welding area 30 and reducing the risk of short circuit caused by burns on the diaphragm 10c or the electrode during welding.

[0167] With reference to Figures 7 to 9, in some embodiments, the welding region 30 includes a first portion 31 located in the second tab stacking region 130b and a second portion 32 located in the first tab stacking region 130a. The first tab stacking region 130a is located outside the second tab stacking region 130b, and the number of tab stacking layers increases from the outside to the inside. By welding the second tab stacking region 130b and the first tab stacking region 130a to the conductive member through the first portion 31 and the second portion 32 of the welding region 30, respectively, the overall size of the welding region 30 can be increased, thereby improving welding strength, reducing resistance in the welding region 30, and thus reducing overcurrent risks. The second portion 32 can be connected to the first portion 31 or spaced apart from the first portion 31.

[0168] In some embodiments, the tab stacking structure 130 further includes a third tab stacking region 130c located on a side of the second tab stacking region 130b adjacent to the winding axis CL, and the welding region 30 further includes a third portion 33 located in the third tab stacking region 130c.

[0169] / The number of tab stacking layers in the third tab stacking area 130c is located on the inner side of the second tab stacking area 130b, and the number of tab stacking layers decreases from the outside to the inside. By welding the third tab stacking area 130c to the conductive parts 21 and 22, the overall size of the welding area 30 can be increased, thereby improving the welding strength and reducing the resistance of the welding area 30, thereby reducing the risk of overcurrent.

[0170] The weld region can be distributed at multiple locations on the conductive member, including continuous or discrete weld segments at different radial or circumferential locations. Referring to FIG9 , it can be seen that the weld region 30 is composed of multiple segments, and the shape can be a straight segment, a curved segment, or a combination of straight segments and curved segments.

[0171] Figure 10 is a schematic diagram illustrating the dimensions of various portions of the welding region in some embodiments of a battery cell according to the present disclosure. For ease of understanding, the welding regions distributed at various locations are schematically arranged within a rectangular area, with dashed lines used to indicate portions of the welding region corresponding to different tab stacking regions. In Figure 10 , the first portion 31 corresponds to the second tab stacking region 130b, the second portion 32 corresponds to the first tab stacking region 130a, and the third portion 33 corresponds to the third tab stacking region 130c.

[0172] Referring 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 weld region 30 satisfies the following: S1 / S ≥ 70%. Here, area S represents the total area of ​​the weld region 30. In Figure 10 , area S is the sum of areas S1, S2, and S3. Referring to the weld region 30 shown in Figure 7 , its three-dimensional shape may be irregular. The area here can be calculated based on the projected area of ​​the weld pool on the surface of the conductive member facing away from the tab stack.

[0173] Since the welding area 30 includes the first part 31 and may also include other parts, 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 tab welding through or cold welding can be reduced.

[0174] Optionally, a 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 is equal to 90%, 95%, 98%, or 100%. By further limiting the ratio S1 / S to ≥ 90%, the welding quality of the welding region 30 can be further improved, effectively reducing the risk of tab welding through or cold welding.

[0175] With reference to Figures 9 and 10 , in some embodiments, the wound structure 100 is a cylindrical wound structure. The ratio L1 / L of the maximum radial length L1 of the first portion 31 in the radial direction of the cylindrical wound structure to the maximum radial length L of the weld region 30 in the radial direction of the cylindrical wound structure satisfies the following: L1 / L ≥ 70%. The maximum radial length L herein refers to the maximum radial length of the weld region 30. In Figure 10 , the maximum radial length L is the sum of the maximum radial lengths L1, L2, and L3.

[0176] When determining the maximum radial length of each part, the positions of each part of the welding area that are farthest and closest to the winding axis CL can be selected, and the difference in the shortest distance from the farthest and closest positions to the winding axis CL can be calculated respectively, which is the maximum radial length of the corresponding part.

[0177] Since the welding area 30 includes the first part 31 and may also include other parts, 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 tab welding through or cold welding can be reduced.

[0178] Optionally, a ratio L1 / L of a maximum radial length L1 of the first portion 31 in the radial direction of the cylindrical wound structure to a maximum radial length L of the welding region 30 in the radial direction of the cylindrical wound structure satisfies the following condition: L1 / L ≥ 90%, for example, L1 / L is equal to 90%, 95%, 98%, or 100%. By further limiting the ratio L1 / L to ≥ 90%, the welding quality of the welding region 30 can be further improved, effectively reducing the risk of tab penetration or cold welding.

[0179] Referring to Figure 6, in some embodiments, the minimum distance d between the winding start end WS of the current collector substrate 11 in the winding direction wd and the second pole tab 132 satisfies: d ≤ 1200 mm. The second pole tab 132 is defined as the pole tab among the multiple pole tabs 13 that is welded to the conductive members 21 and 22 and is closest to the winding start end WS. Here, the second pole tab 132 is located on the side of the first pole tab 131 away from the winding start end WS. In other embodiments, the second pole tab 132 may also be the first pole tab 131, that is, the first pole tab of the pole sheet welded to the conductive members 21 and 22.

[0180] The minimum distance d here is not easy to measure when the electrode sheet is in a wound state. The value of the minimum distance d can be obtained by measuring the electrode sheet in a flattened state. In this case, the winding direction wd is also equivalent to being flattened along with the electrode sheet to be parallel to the length direction of the electrode sheet. Because the second electrode tab 132 is welded to the conductive members 21 and 22 and is closest to the winding starting end WS, the minimum distance d between the second electrode tab 132 and the winding starting end WS can reflect the range of the electrode tab that is directly connected to the conductive members 21 and 22 through the welding area 30.

[0181] The charge on the electrode sheet flows toward the conductive member through the welding area between the multiple electrode tabs and the conductive member. However, the charge in the portion of the electrode sheet between the second electrode tab 132 and the start of the winding flows more toward the second electrode tab 132, making the second electrode tab 132 more susceptible to overcurrent. By setting the minimum distance d to be less than or equal to 1200 mm, the range of the electrode tab directly connected to the conductive members 21 and 22 through the welding area 30 can be increased, reducing the risk of overcurrent in the second electrode tab 132, thereby minimizing the risk of overheating of the electrode tab and affecting the properties of the chemical substances in the electrode assembly 10.

[0182] Optionally, the minimum distance d satisfies: d≤800 mm, for example, d is equal to 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 members 21 and 22 through the welding area 30 can be greatly increased, further reducing the risk of overcurrent in the first tab 131, thereby more effectively preventing the tab from overheating and affecting the properties of the chemical substances in the electrode assembly 10.

[0183] Referring to FIG. 7 , in some embodiments, the maximum depth H of the weld region 30 and the thickness t of the conductive members 21 and 22 along the extension direction of the winding axis CL satisfy the following relationship: 1.5*t≤Hmax≤1.9*t. When the conductive members 21 and 22 are welded to the stacked tabs, a molten weld pool is formed extending from the surfaces of the conductive members 21 and 22 toward the tabs. Depending on factors such as the welding power and overlap thickness, the ratio of the depth of the weld region 30 (i.e., the molten weld pool) to the thickness of the conductive members 21 and 22 can fall within a certain range of values.

[0184] The depth H of the weld region 30 can be measured relative to the surface of the conductive members 21 and 22 on the side away from the electrode assembly. For a particular weld pool, the depth of the weld pool is the distance from the deepest point of the weld pool along the direction of the winding axis CL to the surface of the conductive member. The maximum and minimum depths Hmax and Hmin of the weld region 30 are the maximum and minimum distances from the deepest point of each portion of the weld region 30 to the surface of the conductive member along the direction of the winding axis CL.

[0185] If the ratio of the maximum depth Hmax of the welding region 30 to the thickness t of the conductive members 21 and 22 is too large, the risk of welding through the tab increases, while if the ratio is too small, the risk of tab weld failure increases. Therefore, by setting a specific range for the ratio of the maximum depth Hmax of the welding region 30 to the thickness t of the conductive members 21 and 22, the risk of tab weld failure and weld failure can be minimized.

[0186] Optionally, in the extension direction of the winding axis CL, the maximum value Hmax of the depth H of the welding region 30 and the thickness t of the conductive members 21 and 22 satisfy the following relationship: 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 optional range of the ratio of the maximum value Hmax of the depth of the welding region 30 to the thickness t of the conductive members 21 and 22, the risks of tab welding through and cold welding can be effectively reduced.

[0187] In some embodiments, the minimum depth H of the weld region 30 (Hmin) and the thickness t of the conductive members 21 and 22 (t) along the winding axis CL satisfy the following relationship: 1.1*t≤Hmin≤1.5*t. If the ratio of the minimum depth Hmin of the weld region 30 to the thickness t of the conductive members 21 and 22 is too large, the risk of tab penetration increases. If the ratio is too small, the risk of tab weld failure increases. Therefore, by setting a specific range for the ratio of the minimum depth Hmin of the weld region 30 to the thickness t of the conductive members 21 and 22, the risks of tab penetration and tab weld failure can be minimized.

[0188] Optionally, in the extension direction of the winding axis CL, the minimum value Hmin of the depth H of the welding region 30 and the thickness t of the conductive members 21 and 22 satisfy the following relationship: 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 optional range of the ratio of the minimum value Hmin of the depth of the welding region 30 to the thickness t of the conductive members 21 and 22, the risks of tab welding through and cold welding can be effectively reduced.

[0189] The difference between the maximum value Hmax and the minimum value Hmin of the depth H of the welding area 30 can reflect the depth variation range of the welding area 30. If the difference is too large, it means that the depth of the welding area 30 varies greatly, which may increase the risk of local weld penetration or cold welding. If the difference is too small, it means that the depth of the welding area 30 is relatively uniform. Considering the difference in the thickness of the tab stack, the risk of local weld penetration or cold welding will increase in the thinner or thicker positions of the stack.

[0190] Therefore, in some embodiments, in the extension direction of the winding axis CL, the difference (Hmax-Hmin) between the maximum value Hmax and 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: 0.2*t≤(Hmax-Hmin)≤0.8*t, which helps to reduce the risk of local welding through or cold welding of the tab.

[0191] Optionally, in the extension direction of the winding axis CL, the difference (Hmax-Hmin) between the maximum value Hmax and the minimum value Hmin of the depth H of the welding region 30 and the thickness t of the conductive members 21 and 22 satisfy the following: 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 optional range of the ratio of the difference (Hmax-Hmin) to the thickness t, the risk of localized welding penetration or cold welding of the tab can be further reduced.

[0192] Figure 11 is a schematic diagram illustrating the overlap of adjacent tabs in different tab stacking regions in some embodiments of a battery cell according to the present disclosure. Figures 12 and 13 are schematic diagrams illustrating the dimensions of tabs of different shapes connected to pole pieces in some embodiments of a battery cell according to the present disclosure. Referring to Figure 11 , the curvature of the pole piece windings at different radial positions of the winding structure 100 varies with the radius, with smaller radii resulting in greater curvature of the pole piece windings.

[0193] The number of tab stacking layers mentioned above is the number of tab stacking layers connected by different pole piece windings, and considering that two or more adjacent tabs connected by the same pole piece winding may overlap with each other, the number of tab stacking layers in the second tab stacking area 130a is equal along the direction close to the winding axis CL. Since the degree of overlap of adjacent tabs is higher at positions closer to the winding axis, the thickness of the tab stack increases in the second tab stacking area 130a along the direction close to the winding axis.

[0194] In Figure 11, the radius of the pole piece winding where the base of the first pole piece (i.e., the first pole piece 131) closest to the winding starting point WS is located is r1, while the radius of the pole piece winding where the base of the pole piece of the pole piece farthest from the winding starting point WS is r2. Among the multiple pole pieces connected by each pole piece winding, adjacent pole pieces may overlap after bending inward. The greater the curvature of the pole piece winding, the more adjacent pole pieces 13 connected to it overlap, and the thickness of the pole piece stack increases accordingly.

[0195] In Figures 12 and 13 , the tab 13 can be bent at its root 13r. The root 13r of the tab 13 can be the location where the tab 13 is cut on the current collector substrate. The width of the top 13t of the tab 13 is defined as w, and the top spacing between the tops 13t of adjacent tabs is defined as e. Referring to Figures 12 and 13 , in some embodiments, in the winding direction wd, the top spacing e between adjacent tabs in the plurality of tabs 13 satisfies the following: e ≤ 0.5 mm.

[0196] The larger the top spacing e between adjacent tabs, the less or no overlap occurs after the adjacent tabs are bent inward. The smaller the top spacing e, the greater the overlap after the adjacent tabs are bent inward. Therefore, by setting the top spacing e between adjacent tabs to be less than or equal to 0.5 mm, the tab stacking degree can be increased, thereby achieving a greater tab stacking thickness and reducing the risk of tab welding penetration.

[0197] Optionally, in the winding direction wd, the top spacing e between adjacent tabs in the plurality of tabs 13 satisfies: e≤0.2 mm, for example, e is 0.2 mm, 0.18 mm, 0.12 mm, 0.06 mm, etc. By further limiting the tab top spacing e to be less than or equal to 0.2 mm, the thickness of the tab stack can be effectively increased, further reducing the risk of tab welding through.

[0198] Taking into account that rectangular or parallelogram-shaped tabs can achieve smaller tab top spacing, which is beneficial to increasing the degree of overlap between adjacent tabs, referring to Figures 12 and 13, in some embodiments, at least part of the multiple tabs 13 are rectangular or parallelogram-shaped, which can increase the thickness of the tab stack and reduce the risk of tab welding through.

[0199] Because the curvature of the electrode winding layer increases closer to the winding axis CL, the connected tabs overlap more, and the thickness of the tab stack gradually increases from the outside to the inside. This allows the welding power to gradually increase from the outside to the inside during welding. Therefore, in some embodiments, the depth of the first portion 31 in the direction of the winding axis CL increases as it approaches the winding axis CL. This weld region 30 with increasing depth from the outside to the inside is beneficial for improving the welding quality of the weld region 30.

[0200] For the embodiment in which the welding area 30 also includes a second part 32 located in the first tab stacking area 130a, considering that the number of tab stacking layers in the first tab stacking area 130a is relatively small and the molten pool depth is relatively small without welding through, the welding power used when welding in the first tab stacking area 130a can be lower than the welding power used when welding in the second tab stacking area 130b. Therefore, in some embodiments, the depth of the first part 31 in the extension direction of the winding axis CL is made smaller than the depth of the second part 32, thereby improving the welding quality of the second part 32 of the first tab stacking area 130a and reducing the risk of tab welding through.

[0201] Figure 14 is a schematic diagram illustrating the dimensions of a bent tab and a central hole in some embodiments of a battery cell according to the present disclosure. Referring to Figures 5, 9, 12, 13, and 14, in some embodiments, the wound structure 100 is a cylindrical wound structure having a central hole 110. The minimum distance r1 between the winding axis CL and the base of the first tab 131 satisfies the following: r1 ≥ h0 + 0.8*R. h0 is the height of the unbent first tab 131 in the direction of the winding axis CL, and R is the radius of the cross-section of the central hole 110 at the end of the wound structure 100.

[0202] In the winding direction wd, the first pole tab 131 is closest to the winding starting end WS of the current collector substrate 11. When the first pole tab 131 bends inward, it is more likely to or covers a larger portion of the center hole 110 than the pole tabs connected to the pole sheet winding with a larger radius. By ensuring that the minimum distance r1 is greater than or equal to the sum of the height h0 of the first pole tab 131 and 0.8 times the radius R of the center hole 110, the first pole tab 131 closest to the winding axis CL, after bending from the outside to the inside, covers no more than 20% of the radius of the center hole 110. This reduces the obstruction of the center hole 110 by the bent pole tab, thereby preventing it from affecting electrolyte injection and reducing the risk of short circuits caused by the pole tab being inserted downward or torn during injection.

[0203] Optionally, a minimum distance r1 between the winding axis CL and the base of the first electrode tab 131 satisfies the following condition: r1 ≥ h0 + R. The minimum distance r1 is greater than or equal to the sum of the height h0 of the first electrode tab 131 and the radius R of the center hole 110. This means that the first electrode tab 131 closest to the winding axis CL does not cover the center hole 110 after being bent from outside to inside, thereby more effectively preventing the impact of the electrode tab blocking the center hole 110 on electrolyte injection.

[0204] Figure 15 is a schematic diagram of the height of the tabs in an unbent state in other embodiments of battery cells according to the present disclosure. Figure 16 is a schematic cross-sectional view of the stacked region of multiple tabs after the tabs in Figure 15 are bent toward the center hole. Referring to Figures 15 and 16, in some embodiments, the multiple tabs 13 include a first tab group 13a and a second tab group 13b. The multiple electrode sheet windings of the first tab group 13a are located outside the at least one electrode sheet winding of the second tab group 13b.

[0205] In the direction of the winding axis CL, the minimum height h1 of the unbent first tab group 13a is greater than the maximum height h2 of the unbent second tab group 13b. By ensuring that the maximum height h2 of the second tab group 13b, located inside the first tab group 13a, is smaller than the minimum height h1 of the first tab group 13a, the first tab 131 connected to the welding region 30 is closer to the winding start end WS, which helps reduce the risk of overcurrent in the first tab 131. Furthermore, the smaller tab height of the first tab group 13a can reduce or eliminate coverage of the central hole 110, effectively preventing the impact of the tab blocking the central hole 110 on electrolyte injection.

[0206] 15 and 16 , the second tab group 13b includes the first tab 131. In the direction of the winding axis CL, the height h2 of the second tab group 13b in the unbent state decreases as it approaches the winding axis CL. In FIG15 , the tab heights of the second tab group 13b gradually decrease as they approach the winding axis CL. This brings the first tab 131 closer to the winding axis CL in FIG16 , thereby expanding the second tab stacking region 130b.

[0207] By decreasing the height of each ring of the tabs in the first tab group 13a from the outside to the inside, the second tab stacking area 130b can be extended more toward the winding axis CL, thereby increasing the range of the second tab stacking area 130b, which is beneficial to increasing the size of the first part 31 of the welding area 30 in the second tab stacking area 130b, improving the welding quality of the welding area 30, and reducing the risk of tab welding through or cold welding.

[0208] Based on the various embodiments of the aforementioned battery cells of the present disclosure, the present disclosure also provides embodiments of batteries using the aforementioned battery cell embodiments. The battery includes a battery cell according to any of the aforementioned embodiments. Batteries using the aforementioned battery cell embodiments can achieve better safety in use.

[0209] In one aspect of the present disclosure, an electrical device is provided, comprising the aforementioned battery. The electrical device using the aforementioned battery can achieve better safety in use.

[0210] While the present disclosure has been described with reference to preferred embodiments, various modifications may be made thereto and equivalent components may be substituted without departing from the scope of the present disclosure. In particular, the various technical features described in the various embodiments may be combined in any manner, provided no structural conflicts exist. The present disclosure is not limited to the specific embodiments disclosed herein, but encompasses all technical solutions within the scope of the claims.

Claims

1. A battery cell (40), comprising: An electrode assembly (10), comprising a plurality of pole pieces (10a, 10b) and a separator (10c) located between adjacent pole pieces (10a, 10b) of opposite polarity among the plurality of pole pieces (10a, 10b), wherein the plurality of pole pieces (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 pole pieces (10a, 10b) comprises a current collector substrate (11) and a plurality of pole ears (13), wherein the plurality of pole ears (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), and at least part of the plurality of pole ears (13) is bent in a direction close to a winding axis (CL) of the winding structure (100), and a pole ear stacking structure (130) is formed at an end of the winding structure (100); A housing (4A) having a chamber for accommodating the electrode assembly (10); an electrode terminal (42) provided on a wall portion of the housing (4A); and The conductive member (21, 22) is welded to the tab stacking structure (130) and is electrically connected to the electrode terminal (42).

2. The battery cell (40) according to claim 1, wherein: The tab stacking structure (130) comprises a first tab stacking region (130a) and a second tab stacking region (130b) arranged from outside to inside along a direction close to the winding axis (CL); the number of tab stacking layers in the first tab stacking region (130a) increases along a direction close to the winding axis (CL); the number of tab stacking layers in the second tab stacking region (130b) is equal along a direction close to the winding axis (CL); and at least a portion of the welding region (30) of the conductive member (21, 22) and the tab stacking structure (130) is located in the second tab stacking region (130b).

3. The battery cell (40) according to claim 2, wherein the welding area (30) includes a first portion located in the second tab stacking area (130b) and a second portion (32) located in the first tab stacking area (130a).

4. A battery cell (40) according to claim 2 or 3, wherein the tab stacking structure (130) further includes a third tab stacking region (130c) located on a side of the second tab stacking region (130b) adjacent to the winding axis (CL), and the welding region (30) further includes a third portion (33) located in the third tab stacking region (130c).

5. The battery cell (40) according to any one of claims 2 to 4, wherein a ratio S1 / S of an area S1 of the first portion (31) to an area S of the welding region (30) satisfies: S1 / S ≥ 70%.

6. The battery cell (40) according to claim 5, wherein a ratio S1 / S of an area S1 of the first portion (31) to an area S of the welding region (30) satisfies: S1 / S ≥ 90%.

7. The battery cell (40) according to any one of claims 2 to 6, wherein the winding structure (100) is a cylindrical winding structure, and a ratio L1 / L of a maximum radial length L1 of the first portion (31) in the radial direction of the cylindrical winding structure to a maximum radial length L of the welding area (30) in the radial direction of the cylindrical winding structure satisfies: L1 / L ≥ 70%.

8. The battery cell (40) according to claim 7, wherein a ratio L1 / L of a maximum radial length L1 of the first portion (31) in the radial direction of the cylindrical winding structure to a maximum radial length L of the welding region (30) in the radial direction of the cylindrical winding structure satisfies: L1 / L ≥ 90%.

9. The battery cell (40) according to any one of claims 1 to 8, 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 electrode tab (132) satisfies: d≤1200 mm; in, The second pole tab (132) is defined as the pole tab among the plurality of pole tabs (13) that is welded to the conductive member (21, 22) and is closest to the winding start end (WS).

10. The battery cell (40) according to claim 9, wherein the minimum distance d satisfies: d≤800 mm.

11. A battery cell (40) according to any one of claims 1 to 10, wherein in the extension direction of the winding axis (CL), the maximum value Hmax of the depth H of the welding area (30) of the conductive member (21, 22) and the tab stacking structure (130) and the thickness t of the conductive member (21, 22) satisfy: 1.5*t≤Hmax≤1.9*t.

12. The battery cell (40) according to claim 11, wherein in the extension direction of the winding axis (CL), the maximum value Hmax of the depth H of the welding area (30) and the thickness t of the conductive member (21, 22) satisfy: 1.6*t≤Hmax≤1.8*t.

13. A battery cell (40) according to any one of claims 1 to 12, wherein in the extension direction of the winding axis (CL), the minimum value Hmin of the depth H of the welding area (30) of the conductive member (21, 22) and the tab stacking structure (130) and the thickness t of the conductive member (21, 22) satisfy: 1.1*t≤Hmin≤1.5*t.

14. The battery cell (40) according to claim 13, wherein in the extension direction of the winding axis (CL), the minimum value Hmin of the depth H of the welding area (30) and the thickness t of the conductive member (21, 22) satisfy: 1.2*t≤Hmin≤1.4*t.

15. A battery cell (40) according to any one of claims 1 to 14, wherein in the extension direction of the winding axis (CL), the difference (Hmax-Hmin) between the maximum value Hmax and the minimum value Hmin of the depth H of the welding area (30) of the conductive member (21, 22) and the tab stacking structure (130) and the thickness t of the conductive member (21, 22) satisfy: 0.2*t≤(Hmax-Hmin)≤0.8*t.

16. The battery cell (40) according to claim 15, wherein in the extension direction of the winding axis (CL), the difference (Hmax-Hmin) between the maximum value Hmax and the minimum value Hmin of the depth H of the welding area (30) and the thickness t of the conductive member (21, 22) satisfy: 0.3*t≤(Hmax-Hmin)≤0.6*t.

17. The battery cell (40) according to any one of claims 1 to 16, wherein in the winding direction (wd), a top spacing e between adjacent pole tabs in the plurality of pole tabs (13) satisfies: e≤0.5 mm.

18. The battery cell (40) according to claim 17, wherein in the winding direction (wd), a top distance e between adjacent pole tabs in the plurality of pole tabs (13) satisfies: e≤0.2 mm.

19. A battery cell (40) according to any one of claims 1 to 18, wherein the welding area (30) of the conductive member (21, 22) and the tab stacking structure (130) includes a first portion located in the second tab stacking area (130b), and in the extension direction of the winding axis (CL), the depth of the first portion (31) increases in a direction approaching the winding axis (CL).

20. A battery cell (40) according to any one of claims 1 to 19, wherein the welding area (30) between the conductive member (21, 22) and the tab stacking structure (130) comprises a first portion located in the second tab stacking area (130b) and a second portion (32) located in the first tab stacking area (130a), and in the extension direction of the winding axis (CL), the depth of the first portion (31) is less than the depth of the second portion (32).

21. The battery cell (40) according to any one of claims 1 to 20, wherein at least part of the plurality of tabs (13) are rectangular or parallelogram-shaped.

22. The battery cell (40) according to any one of claims 1 to 21, wherein the winding structure (100) is a cylindrical winding structure, the cylindrical winding structure has a central hole (110), and the minimum distance r1 between the winding axis (CL) and the root of the first tab (131) satisfies: r1≥h0+0.8*R; in, h0 is the height of the first electrode tab in an unbent state in the extension direction of the winding axis (CL), and R is the radius of the hole cross section of the center hole (110) at the end of the winding structure (100).

23. The battery cell (40) according to claim 22, wherein a minimum distance r1 between the winding axis (CL) and a root of the first tab (131) satisfies: r1 ≥ h0 + R.

24. A battery cell (40) according to any one of claims 1 to 23, wherein the plurality of pole tabs (13) include a first pole tab group (13a) and a second pole tab group (13b), the plurality of pole sheet windings of the first pole tab group (13a) being located are located outside at least one pole sheet winding of the second pole tab group (13b), and in the extension direction of the winding axis (CL), the minimum height h1 of the first pole tab group (13a) in an unbent state is greater than the maximum height h2 of the second pole tab group (13b) in an unbent state.

25. The battery cell (40) according to claim 24, wherein the second pole lug group (13b) includes the first pole lug (131), and in the extension direction of the winding axis (CL), the height h2 of the second pole lug group (13b) in the unbent state decreases toward the direction approaching the winding axis (CL).

26. A battery cell (40) according to any one of claims 1 to 25, wherein the outer shell (4A) comprises a shell (41) and an end cover (42), one end of the shell (41) has an opening (411), the end cover (42) covers the opening (411), the shell (41) comprises a side wall (414) and a bottom wall (413), the side wall (414) surrounds the outer side of the electrode assembly (10), the bottom wall (413) is arranged opposite to the opening (411), and the wall portion of the outer shell (4A) is the end cover (42) or the bottom wall (413).

27. A battery (50), comprising: A battery cell (40) as claimed in any one of claims 1 to 26.

28. An electrical device comprising: The battery (50) as claimed in claim 27.

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