Battery cell, battery, and electric device

Abstract

A battery cell (30), a battery (40), and an electrical device are disclosed. The battery cell (30) includes: an electrode assembly (10) comprising a first electrode (11), a second electrode (12), and a separator (13), wherein the first electrode (11) and the second electrode (12) have opposite polarities, and the separator (13) is located between the first electrode (11) and the second electrode (12). The first electrode (11), the second electrode (12), and the separator (13) are wound along a winding direction to form a winding structure (100). The first electrode (11) includes a plurality of first tabs (11B) bent at the ends of the winding structure (100) to form a first tab stack structure (111). The second electrode (12)... The structure includes a plurality of second tabs (12B) that are bent at the end of the winding structure (100) to form a second tab stack structure (121); a first conductive element (21) welded to the first tab stack structure (111); and a second conductive element (22) welded to the second tab stack structure (121), wherein at least one of the bending positions (11f) of the plurality of first tabs (11B) and the bending positions (12f) of the plurality of second tabs (12B) has a gap with the spacer (13) in the first direction (d1) parallel to the winding axis extension direction of the winding structure (100).

Description

[0001] Cross-reference to related applications

[0002] This application is based on and claims priority to Chinese Patent Application No. 202310955457.7, filed on August 1, 2023, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0003] This disclosure relates to the field of battery technology, and in particular to a battery cell, a battery, and an electrical device. Background Technology

[0004] Secondary batteries, especially lithium-ion batteries, have advantages such as high voltage, high specific energy, long cycle life, being environmentally friendly and pollution-free, having a wide operating temperature range, and low self-discharge. They are widely used in portable electronic devices and power equipment for large new energy electric vehicles, and are of great significance in solving environmental pollution and the energy crisis. With the widespread use of lithium-ion batteries, battery safety has become a major concern for users. Summary of the Invention

[0005] In one aspect of this disclosure, a battery cell is provided, comprising: an electrode assembly including a first electrode, a second electrode, and a separator, wherein the first electrode and the second electrode have opposite polarities, the separator is located between the first electrode and the second electrode, the first electrode, the second electrode, and the separator are wound along a winding direction to form a wound structure, the first electrode including a plurality of first tabs bent at the ends of the wound structure to form a first tab stack structure, the second electrode including a plurality of second tabs bent at the ends of the wound structure to form a second tab stack structure; a first conductive element welded to the first tab stack structure; and a second conductive element welded to the second tab stack structure, wherein, in a first direction parallel to the extension direction of the winding axis of the wound structure, at least one of the bending positions of the plurality of first tabs and the bending positions of the plurality of second tabs has a gap with the separator in the first direction.

[0006] Multiple first tabs and multiple second tabs are bent at the ends of the winding structure to form a first tab stack structure and a second tab stack structure, respectively. By making at least one of the bending positions of the multiple first tabs and the multiple second tabs have a gap with the insulating member in the first direction, the risk of heat generated by the tabs being conducted to the insulating member and causing burns to the insulating member can be reduced during the welding process of the tab stack structure and the conductive member, thereby improving product yield and safety of use.

[0007] In some embodiments, the minimum distance between the bending positions of the plurality of first tabs and the gap between the spacer in the first direction is defined as a first minimum distance L1, and the minimum distance between the bending positions of the plurality of second tabs and the gap between the spacer in the first direction is defined as a second minimum distance L2; the melting point of the material of the plurality of first tabs is less than the melting point of the material of the plurality of second tabs, and the first minimum distance L1 is less than or equal to the second minimum distance L2.

[0008] For a single-cell embodiment where the melting point of the first tab material is lower than that of the second tab material, the second tab material with a larger melting point requires greater welding heat to form a weld pool. Consequently, the second tab stack structure generates more heat during welding. By increasing the second minimum distance L2, the risk of burns to the separator part corresponding to the second tab stack structure and the risk of thermal radiation burns caused by the separator being too close to the second tab stack structure can be reduced.

[0009] In some embodiments, the minimum distance between the bending positions of the plurality of first tabs and the gap between the spacer in the first direction is defined as a first minimum distance L1, and the minimum distance between the bending positions of the plurality of second tabs and the gap between the spacer in the first direction is defined as a second minimum distance L2; the melting point of the material of the plurality of first tabs is greater than the melting point of the material of the plurality of second tabs, and the second minimum distance L2 is less than or equal to the first minimum distance L1.

[0010] For a single-cell battery embodiment where the melting point of the first tab material is greater than that of the second tab material, the first tab material with a larger melting point requires greater welding heat to form a weld pool. Consequently, the first tab stack structure generates more heat during welding. By ensuring that the first minimum distance L1 is not less than the second minimum distance L2, the risk of burns to the separator part corresponding to the first tab stack structure and the risk of thermal radiation burns caused by the separator being too close to the first tab stack structure can be reduced.

[0011] In some embodiments, the bending position of the plurality of first electrodes is at the cut root of the plurality of first electrodes, and / or, the bending position of the plurality of second electrodes is at the cut root of the plurality of second electrodes.

[0012] The bending positions of the multiple first tabs can be the cutting positions of the tabs on the portion of the current collector substrate of the first electrode sheet not covered by the active material layer. Correspondingly, the first minimum distance L1 is the distance between the cut roots of the multiple first tabs and the spacer in the first direction. The bending positions of the multiple second tabs can also be the cutting positions of the tabs on the portion of the current collector substrate of the second electrode sheet not covered by the active material layer. Correspondingly, the second minimum distance L2 is the distance between the cut roots of the multiple second tabs and the spacer in the first direction.

[0013] In some embodiments, in the first direction, there is a third minimum distance L3 between the bending position of the plurality of first electrodes and the top of the electrodes of the plurality of first electrodes, and a fourth minimum distance L4 between the bending position of the plurality of second electrodes and the top of the electrodes of the plurality of second electrodes; the first thickness t1 of the plurality of first electrodes in the thickness direction of the first electrodes is less than the second thickness t2 of the plurality of second electrodes in the thickness direction of the second electrodes, and the third minimum distance L3 is greater than or equal to the fourth minimum distance L4.

[0014] The third minimum distance L3 and the fourth minimum distance L4 represent the lengths of the first and second tabs when bent and participating in the stacking process, respectively. The longer the length of the tabs participating in the stacking process, the higher the degree of tab overlap. The first thickness t1 of the first tab represents the thickness of a single layer of the first tab, and the second thickness t2 of the second tab represents the thickness of a single layer of the second tab. The thicker the single-layer tab, the thicker the stacked tab structure. For a single-cell embodiment where the first thickness t1 is less than the second thickness t2, by making the third minimum distance L3 greater than or equal to the fourth minimum distance L4, the thicknesses of the first and second tab stacked structures can be made closer, which helps to reduce the risk of burns or scalds to the separator due to differences in welding heat when forming the weld pool.

[0015] In some embodiments, in the first direction, there is a third minimum distance L3 between the bending position of the plurality of first electrodes and the top of the electrodes of the plurality of first electrodes, and a fourth minimum distance L4 between the bending position of the plurality of second electrodes and the top of the electrodes of the plurality of second electrodes; the first thickness t1 of the plurality of first electrodes in the thickness direction of the first electrodes is greater than the second thickness t2 of the plurality of second electrodes in the thickness direction of the second electrodes, and the third minimum distance L3 is less than or equal to the fourth minimum distance L4.

[0016] The third minimum distance L3 and the fourth minimum distance L4 represent the lengths of the first and second tabs when bent and participating in the stacking process, respectively. The longer the length of the tabs participating in the stacking process, the higher the degree of tab overlap. The first thickness t1 of the first tab represents the thickness of a single layer of the first tab, and the second thickness t2 of the second tab represents the thickness of a single layer of the second tab. The thicker the single-layer tab, the thicker the stacked tab structure. For a single-cell embodiment where the first thickness t1 is greater than the second thickness t2, by making the third minimum distance L3 less than or equal to the fourth minimum distance L4, the thicknesses of the first and second tab stacked structures can be made closer, which helps to reduce the risk of burns or scalds to the separator due to differences in welding heat when forming the weld pool.

[0017] In some embodiments, the ratio A / B of the product A of the first thickness t1 and the third minimum distance L3 of the plurality of first electrodes in the thickness direction of the first electrodes and the product B of the second thickness t2 and the fourth minimum distance L4 of the plurality of second electrodes in the thickness direction of the second electrodes satisfies: 0.2≤A / B≤4, wherein the units of the first thickness t1, the second thickness t2, the third minimum distance L3, and the fourth minimum distance L4 are the same.

[0018] The product A of the first thickness t1 and the third minimum distance L3 reflects the stacking thickness of the first tab stack structure, and the product B of the second thickness t2 and the fourth minimum distance L4 reflects the stacking thickness of the second tab stack structure. The ratio of the product A to the product B reflects the degree of difference in stacking thickness between the first and second tab stack structures. If the ratio A / B is too large, the first tab stack structure is thicker, requiring higher welding power and higher welding heat during welding, thus increasing the risk of burns or scalds to the insulating part corresponding to the first tab stack structure compared to the second tab stack structure. Conversely, if the ratio A / B is too small, the second tab stack structure is thicker, requiring higher welding power and higher welding heat during welding, thus increasing the risk of burns or scalds to the insulating part corresponding to the second tab stack structure compared to the first tab stack structure. Therefore, by ensuring that the ratio A / B satisfies: 0.2≤A / B≤4, the difference in stacking thickness between the first tab stack structure and the second tab stack structure is reduced, thereby reducing the risk of burns or scalds to the insulating parts corresponding to the first tab stack structure and the second tab stack structure.

[0019] In some embodiments, the ratio A / B satisfies: 0.5 ≤ A / B ≤ 2.

[0020] By further limiting the ratio A / B to satisfy: 0.5≤A / B≤2, the difference in stacking thickness between the first tab stack structure and the second tab stack structure can be further reduced, thereby more effectively reducing the risk of burns or scalds to the insulating parts corresponding to the first tab stack structure and the second tab stack structure.

[0021] In some embodiments, the ratio A / B of the product A of the first thickness t1 and the third minimum distance L3 of the plurality of first electrodes in the thickness direction of the first electrodes and the product B of the second thickness t2 and the fourth minimum distance L4 of the plurality of second electrodes in the thickness direction of the second electrodes satisfies: A / B<1, wherein the units of the first thickness t1, the second thickness t2, the third minimum distance L3, and the fourth minimum distance L4 are the same, and the third thickness t3 of the first conductive element in the first direction is less than the fourth thickness t4 of the second conductive element in the first direction.

[0022] The product A of the first thickness t1 and the third minimum distance L3 represents the stacking thickness of the first tab stack structure, and the product B of the second thickness t2 and the fourth minimum distance L4 represents the stacking thickness of the second tab stack structure. For battery cell embodiments where the product A is less than the product B, the second tab stack structure with a larger stacking thickness requires higher welding power. However, when the laser power fluctuates, it is easy to form an excessively deep molten pool, increasing the risk of burns or scalds to the separator. Therefore, a thicker second conductive element is used to increase the welding tolerance and reduce the possibility of forming an excessively deep molten pool, thereby reducing the risk of burns or scalds to the separator corresponding to the second tab stack structure. Conversely, a thinner first conductive element, combined with a first tab stack structure with a smaller stacking thickness, allows for welding with lower power, making it easier to form a molten pool of suitable depth and reducing the risk of burns or scalds to the separator corresponding to the first tab stack structure.

[0023] In some embodiments, the ratio A / B of the product A of the first thickness t1 and the third minimum distance L3 of the plurality of first electrodes in the thickness direction of the first electrodes and the product B of the second thickness t2 and the fourth minimum distance L4 of the plurality of second electrodes in the thickness direction of the second electrodes satisfies: A / B>1, wherein the units of the first thickness t1, the second thickness t2, the third minimum distance L3, and the fourth minimum distance L4 are the same, and the third thickness t3 of the first conductive element in the first direction is greater than the fourth thickness t4 of the second conductive element in the first direction.

[0024] The product A of the first thickness t1 and the third minimum distance L3 represents the stacking thickness of the first tab stack structure, and the product B of the second thickness t2 and the fourth minimum distance L4 represents the stacking thickness of the second tab stack structure. For battery cell embodiments where the product B is less than the product A, the first tab stack structure with a larger stacking thickness requires higher welding power. However, when the laser power fluctuates, it is easy to form an excessively deep molten pool, increasing the risk of burns or scalds to the separator. Therefore, a thicker first conductive element is used to increase the welding tolerance and reduce the possibility of forming an excessively deep molten pool, thereby reducing the risk of burns or scalds to the separator corresponding to the first tab stack structure. Conversely, a thinner second conductive element, combined with a second tab stack structure with a smaller stacking thickness, allows for welding with lower power, making it easier to form a molten pool of suitable depth, further reducing the risk of burns or scalds to the separator corresponding to the second tab stack structure.

[0025] In some embodiments, in the first direction, the first tab stack structure and the second tab stack structure are both located at the same end of the winding structure.

[0026] Multiple first tabs and multiple second tabs can be distributed on the same end of the winding structure. The first tab stack structure and the second tab stack structure obtained by bending and stacking can be at different angles on the end of this side. Correspondingly, the first conductive element and the second conductive element are also disposed on the same side of the winding structure and are welded to the first tab stack structure and the second tab stack structure respectively.

[0027] In some embodiments, in the first direction, the first tab stack structure and the second tab stack structure are located at opposite ends of the winding structure.

[0028] Multiple first tabs and multiple second tabs can be distributed at opposite ends of the winding structure. The multiple first tabs and multiple second tabs that are bent and stacked form a first tab stack structure and a second tab stack structure at both ends of the winding structure, respectively. Correspondingly, the first conductive element and the second conductive element are also respectively disposed on both sides of the winding structure and are welded to the first tab stack structure and the second tab stack structure, respectively.

[0029] In some embodiments, the battery cell further includes: a housing having a chamber for accommodating the electrode assembly, the first conductive element, and the second conductive element; and electrode terminals disposed on the wall of the housing and electrically connected to the first conductive element or the second conductive element.

[0030] The first and second electrode stack structures formed at the ends of the winding structure of the electrode assembly are welded to the first and second conductive elements, respectively, and electrically connected to the electrode terminals disposed on the outer casing wall through the first or second conductive element. Since the stacked multi-layer electrode structure has a higher thickness, it is not easy to be welded through when welding with the conductive element, reducing the risk of burning or scalding the insulating element in the electrode assembly during welding, thereby improving the welding quality of the welding area and improving the safety of use.

[0031] In some embodiments, the housing includes a housing and an end cap, one end of the housing having an opening, the end cap covering the opening, the housing including a side wall and a bottom wall, the side wall surrounding the outside of the electrode assembly, the bottom wall being disposed opposite to the opening, and the wall portion of the housing being the end cap or the bottom wall.

[0032] The first and second electrode stack structures formed at the ends of the winding structure of the electrode assembly are welded to the first and second conductive elements, respectively, and electrically connected to the electrode terminals disposed on the bottom wall of the end cap or housing through the first or second conductive element. This can effectively reduce the risk of burning or scalding the insulating elements in the electrode assembly during welding, improve the welding quality of the welding area, and enhance the safety of use.

[0033] In some embodiments, the first electrode further includes a first current collector substrate, the plurality of first tabs are connected to the first current collector substrate and are arranged at intervals along the winding direction, wherein the bending positions of the plurality of first tabs are located on the side of the separator away from the first current collector substrate in the first direction; the second electrode further includes a second current collector substrate, the plurality of second tabs are connected to the second current collector substrate and are arranged at intervals along the winding direction, wherein the bending positions of the plurality of second tabs are located on the side of the separator away from the second current collector substrate in the first direction.

[0034] At least portions of a plurality of first tabs, connected to a first current collector substrate and spaced apart along the winding direction, are bent at the ends of the winding structure to form a tightly packed first tab stack structure with a certain thickness, which can be welded to a first conductive element to achieve a reliable electrical connection. Similarly, at least portions of a plurality of second tabs, connected to a second current collector substrate and spaced apart along the winding direction, are bent at the ends of the winding structure to form a tightly packed second tab stack structure with a certain thickness, which can be welded to a second conductive element to achieve a reliable electrical connection.

[0035] In one aspect of this disclosure, a battery is provided, comprising: the aforementioned battery cell.

[0036] Batteries using the aforementioned battery cells can effectively improve safety during use.

[0037] In one aspect of this disclosure, an electrical device is provided, comprising: the aforementioned battery.

[0038] Electrical devices using the aforementioned batteries can effectively improve safety during use. Attached Figure Description

[0039] To more clearly illustrate the technical solutions of the embodiments of this disclosure, the accompanying drawings used in the embodiments of this disclosure will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on the drawings without creative effort.

[0040] This disclosure will become clearer with reference to the accompanying drawings and the following detailed description, wherein:

[0041] Figure 1 These are schematic diagrams of the structure of some embodiments of the electrical device according to this disclosure;

[0042] Figure 2 This is an exploded view of some embodiments of the battery according to the present disclosure;

[0043] Figure 3This is a schematic diagram showing the connection of multiple battery cells according to some embodiments of the battery disclosed herein;

[0044] Figure 4 This is an exploded view of some embodiments of the battery cell according to the present disclosure;

[0045] Figure 5 This is a schematic longitudinal section diagram of a battery cell according to some embodiments of the present disclosure via a winding shaft CL;

[0046] Figure 6 This is a schematic cross-sectional view of the winding structure according to some embodiments of the electrode assembly of this disclosure;

[0047] Figure 7 This is an exploded schematic diagram of the electrode assembly and conductive elements in some embodiments of the battery cell according to this disclosure;

[0048] Figure 8 This is an exploded schematic diagram of the electrode assembly and conductive elements in some other embodiments of the battery cell according to this disclosure;

[0049] Figure 9 and Figure 10 They are Figure 8 A schematic diagram of the assembly structure and cross-section of the conductive components;

[0050] Figure 11 This is a schematic diagram of the electrode plates and tabs in an unfolded state according to some embodiments of the electrode assembly of this disclosure;

[0051] Figure 12 This is a schematic diagram of the electrode plates and tabs in an unfolded state according to other embodiments of the electrode assembly of this disclosure;

[0052] Figure 13 This is a schematic cross-sectional view of the electrode stack structure and the conductive element welded together in some embodiments of the electrode assembly according to this disclosure.

[0053] It should be understood that the dimensions of the various parts shown in the accompanying drawings are not drawn to actual scale. Furthermore, the same or similar reference numerals denote the same or similar components.

[0054] Explanation of reference numerals in the attached figures:

[0055] 10-Electrode assembly; 11-First electrode; 11A-First current collector substrate; 11B-First tab; 11C-First active material layer; 111-First tab stacking structure; 11f-Bending position of the first tab; 11r-Cut root of the first tab; 11t-Top of the first tab; 12-Second electrode; 12B-Second tab; 12C-Second active material layer; 121-Second tab stacking structure; 12f-Bending position of the second tab; 12r-Cut root of the second tab; 12t-Top of the second tab; 13-Separator; 100-Wound structure;

[0056] 21-First conductive element; 22-Second conductive element; 23-Second insulating element;

[0057] 30-Battery cell; 31-Casing; 311-Shell; 311B-Side wall; 311C-Bottom wall; 311A-Opening; 311D-Through hole; 312-End cap; 32-Electrode terminal; 33-First insulating component; 34-Electrode lead-out part; 35-Pressure relief component;

[0058] 40-Battery; 41-Box body; 42-Box cover; 43-Busbar;

[0059] 50 - Vehicles;

[0060] wd - winding direction; CL - winding axis; d1 - first direction; d2 - second direction. Detailed Implementation

[0061] The embodiments of this disclosure will be further described in detail below with reference to the accompanying drawings and examples. The following detailed description of the embodiments and the accompanying drawings are used to illustrate the principles of this disclosure by way of example, but should not be used to limit the scope of this disclosure, that is, this disclosure is not limited to the described embodiments.

[0062] In the description of this disclosure, it should be noted that, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," "outer," etc., indicating orientation or positional relationships are only for the convenience of describing this disclosure and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this disclosure. Furthermore, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. "Vertical" is not vertical in the strict sense, but within the allowable tolerance range. "Parallel" is not parallel in the strict sense, but within the allowable tolerance range.

[0063] The directional terms used in the following description refer to the directions shown in the figures and are not intended to limit the specific structure of this disclosure. It should also be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this disclosure based on the specific circumstances.

[0064] The following detailed description of some embodiments of the present invention is provided in conjunction with the accompanying drawings. Unless otherwise specified, features in the following embodiments can be combined with each other.

[0065] In this disclosure, "multiple" means two or more (including two).

[0066] In this embodiment of the disclosure, the battery cell can be a secondary battery, which refers to a battery cell that can be recharged to activate the active materials and continue to be used after the battery cell has been discharged.

[0067] The battery cell can be a lithium-ion battery, sodium-ion battery, sodium-lithium-ion battery, lithium metal battery, sodium metal battery, lithium-sulfur battery, magnesium-ion battery, nickel-metal hydride battery, nickel-cadmium battery, lead-acid battery, etc., and the embodiments of this application are not limited to this.

[0068] A battery cell includes an electrode assembly. The electrode assembly includes a first electrode and a second electrode with opposite polarities, and a separator disposed between the first and second electrodes. In some embodiments, the first electrode is a positive electrode and the second electrode is a negative electrode. In other embodiments, the first electrode is a negative electrode and the second electrode is a positive electrode. During the charging and discharging process of the battery cell, active ions (e.g., lithium ions) repeatedly insert and extract between the positive and negative electrodes. The separator, disposed between the positive and negative electrodes, prevents short circuits between the positive and negative electrodes while allowing active ions to pass through.

[0069] In some embodiments, the positive electrode may include a positive current collector substrate and a positive active material layer disposed on at least one surface of the positive current collector substrate.

[0070] As an example, the positive current collector substrate has two surfaces opposite each other in its own thickness direction, and the positive active material layer is disposed on either or both of the two opposite surfaces of the positive current collector substrate.

[0071] As an example, the positive electrode current collector substrate can be a metal foil or a composite current collector. For example, as a metal foil, silver-treated aluminum or stainless steel, stainless steel, copper, aluminum, nickel, carbon electrodes, carbon, nickel, or titanium, etc., can be used. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector can be formed by applying a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) onto a polymer material base material (such as a polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc. base material).

[0072] As an example, the positive electrode active material layer may include at least one of the following materials: lithium phosphate, lithium transition metal oxide, and their respective modified compounds. However, this disclosure is not limited to these materials, and other conventional materials that can be used as positive electrode active material layers in batteries may also be used. These positive electrode active material layers may be used alone or in combination of two or more. Examples of lithium phosphate include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO4), lithium manganese phosphate and carbon composites, lithium iron manganese phosphate, and lithium iron manganese phosphate and carbon composites. Examples of lithium transition metal oxides include, but are not limited to, lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, and lithium nickel cobalt manganese oxide (such as LiNi). 1 / 3 Co 1 / 3Mn 1 / 3 O2 (also known as NCM) 333 LiNi 0.5 Co 0.2 Mn 0.3 O2 (also known as NCM) 523 LiNi 0.5 Co 0.25 Mn 0.25 O2 (also known as NCM) 211 LiNi 0.6 Co 0.2 Mn 0.2 O2 (also known as NCM) 622 LiNi 0.8 Co 0.1 Mn 0.1 O2 (also known as NCM) 811 ), lithium nickel cobalt aluminum oxide (such as LiNi) 0.85 Co 0.15 Al 0.05 At least one of O2 and its modified compounds.

[0073] In some implementations, the negative electrode may include a negative current collector substrate.

[0074] As an example, the negative electrode current collector substrate can be a metal foil, a foamed metal, or a composite current collector. For example, as a metal foil, it can be silver-treated aluminum or stainless steel, stainless steel, copper, aluminum, nickel, carbon electrodes, carbon, nickel, or titanium, etc. Foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloy, or foamed carbon, etc. Composite current collectors can include a polymer material base layer and a metal layer. Composite current collectors can be formed by applying a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) onto a polymer material base material (such as a base material of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0075] In some embodiments, 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.

[0076] As an example, the negative electrode current collector substrate has two surfaces opposite each other in its own thickness direction, and the negative electrode active material layer is disposed on either or both of the two opposite surfaces of the negative electrode current collector substrate.

[0077] As an example, the negative electrode active material layer may employ a type of negative electrode active material layer known in the art for use in battery cells. As an example, the negative electrode active material layer may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate, etc. Silicon-based materials may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. Tin-based materials may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, this disclosure is not limited to these materials, and other conventional materials that can be used as negative electrode active material layers in batteries may also be used. These negative electrode active material layers may be used alone or in combination of two or more.

[0078] In some embodiments, the positive electrode current collector substrate can be made of aluminum, and the negative electrode current collector substrate can be made of copper.

[0079] In some embodiments, the separator is a separator membrane. This disclosure does not impose any particular limitation on the type of separator membrane; any known porous separator membrane with good chemical and mechanical stability can be selected.

[0080] As an example, the main material of the separator can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramic. The separator can be a single-layer film or a multi-layer composite film, without particular limitation. When the separator is a multi-layer composite film, the materials of each layer can be the same or different, without particular limitation. The separator can be a separate component located between the positive and negative electrode plates, or it can be located between the positive and negative electrode plates while being attached to the surface of the positive electrode plate and / or the surface of the negative electrode plate.

[0081] In some embodiments, the separator is a solid electrolyte. The solid electrolyte is disposed between the positive and negative electrode plates, serving both to transport ions and to isolate the positive and negative electrodes.

[0082] In some embodiments, the battery cell also includes an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. This disclosure does not impose specific limitations on the type of electrolyte; it can be selected according to requirements. The electrolyte can be liquid, gel, or solid.

[0083] As an example, liquid electrolytes include electrolyte salts and solvents.

[0084] In some embodiments, the electrolyte salt may be selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalate borate, lithium dioxalate borate, lithium difluorodioxalate phosphate, and lithium tetrafluorooxalate phosphate.

[0085] In some embodiments, the solvent may be selected from at least one of ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butyl carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone. The solvent may also be an ether solvent. Ether solvents may include one or more of ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyl tetrahydrofuran, diphenyl ether, and crown ethers.

[0086] As an example, gel electrolytes include a polymer-based backbone network combined with an ionic liquid—a lithium salt.

[0087] As an example, solid electrolytes include polymer solid electrolytes, inorganic solid electrolytes, and composite solid electrolytes.

[0088] As an example, polymer solid electrolytes can be polyether (polyoxyethylene), polysiloxane, polycarbonate, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, monoionic polymers, polyionic liquids-lithium salts, cellulose, etc.

[0089] As an example, inorganic solid electrolytes can be one or more of the following: oxide solid electrolytes (crystalline perovskite, sodium superconducting ion conductor, garnet, amorphous LiPON thin film), sulfide solid electrolytes (crystalline lithium superconducting ion conductor (lithium germanium phosphorus sulfide, silver sulfide germanium ore), amorphous sulfides), halide solid electrolytes, nitride solid electrolytes, and hydride solid electrolytes.

[0090] As an example, composite solid electrolytes are formed by adding inorganic solid electrolyte fillers to polymer solid electrolytes.

[0091] In some embodiments, the electrode assembly includes a wound structure. A positive electrode, a negative electrode, and a separator are wound into the wound structure. One or more positive and negative electrodes may be provided respectively. As an example, multiple positive and multiple negative electrodes are alternately arranged along the electrode thickness direction.

[0092] In some embodiments, the electrode assembly can be cylindrical, flat, or polygonal in shape.

[0093] In some embodiments, the positive electrode includes a positive electrode tab, and the negative electrode includes a negative electrode tab. The positive and negative electrode tabs are used to conduct current from the electrode assembly. The positive and negative electrode tabs are respectively connected to the positive and negative current collector substrates. The tabs can be formed by cutting or trimming the current collector substrate, or they can be welded to the side of the current collector substrate.

[0094] In some embodiments, the battery cell may include a housing. The housing is used to encapsulate components such as electrode assemblies and electrolytes. The housing may be made of steel, aluminum, plastic (such as polypropylene), composite metal (such as copper-aluminum composite), or aluminum-plastic film, etc.

[0095] As an example, a battery cell can be a cylindrical battery cell, a prismatic battery cell, a pouch battery cell, or a battery cell of other shapes. Prismatic battery cells include prismatic battery cells, blade-shaped battery cells, and multi-prismatic batteries, such as hexagonal prismatic batteries.

[0096] The battery mentioned in the embodiments of this disclosure refers to a single physical module comprising one or more battery cells to provide higher voltage and capacity.

[0097] In some embodiments, the battery can be a battery module. When there are multiple battery cells, the multiple battery cells are arranged and fixed to form a battery module. The battery module may include multiple battery cells connected in series, parallel, or in a mixed configuration.

[0098] In some embodiments, the battery can be a battery pack, which includes a housing and individual battery cells, with the individual battery cells or battery modules housed within the housing.

[0099] In some embodiments, the housing may be part of the vehicle's chassis structure. For example, a portion of the housing may be at least a part of the vehicle's floor, or a portion of the housing may be at least a part of the vehicle's crossbeams and longitudinal beams.

[0100] In some embodiments, the battery can be an energy storage device. Energy storage devices include energy storage containers, energy storage cabinets, etc.

[0101] In some related technologies, the electrode in the electrode assembly mainly consists of a current collector substrate and an active material layer disposed on the surface of the current collector substrate. In the width direction of the electrode, the portion of the current collector substrate that extends beyond the active material layer is the current collection output area. This area is cut to obtain multiple smaller tabs located on the side of the current collector substrate, with cuts between adjacent tabs to make each tab independent.

[0102] These smaller tabs are bent and flattened at the ends of the wound electrode assembly to form a denser tab stack structure. When the tab stack structure is welded to the current collector by laser or other methods, the heat generated by the tab stack structure may burn the insulating component in contact with the tab through heat conduction, causing the insulating component to break and fail, affecting product yield and safety of use.

[0103] In view of this, embodiments of the present disclosure provide a battery cell, including: an electrode assembly, a first conductive element, and a second conductive element. The electrode assembly includes a first electrode, a second electrode, and a separator, wherein the first electrode and the second electrode have opposite polarities, and the separator is located between the first electrode and the second electrode. The first electrode, the second electrode, and the separator are wound along a winding direction to form a winding structure. The first electrode includes a plurality of first tabs bent at the ends of the winding structure to form a first tab stack structure, and the second electrode includes a plurality of second tabs bent at the ends of the winding structure to form a second tab stack structure. A first conductive element is welded to the first tab stack structure; and a second conductive element is welded to the second tab stack structure. In a first direction parallel to the extension direction of the winding axis of the winding structure, at least one of the bending positions of the plurality of first tabs and the bending positions of the plurality of second tabs has a gap with the separator in the first direction.

[0104] Multiple first tabs and multiple second tabs are bent at the ends of the winding structure to form a first tab stack structure and a second tab stack structure, respectively. By making at least one of the bending positions of the multiple first tabs and the multiple second tabs have a gap with the insulating member in the first direction, the risk of heat generated by the tabs being conducted to the insulating member and causing burns to the insulating member can be reduced during the welding process of the tab stack structure and the conductive member, thereby improving product yield and safety of use.

[0105] The battery cells of this disclosure are applicable to various types of batteries. The battery may include a housing and a battery module. The housing provides space for the battery module, which is mounted within the housing. The housing may be made of metal. The battery module may include multiple battery cells connected in series, parallel, or a combination thereof. A battery cell is the smallest unit constituting a battery. A battery cell includes electrode components capable of undergoing electrochemical reactions.

[0106] The battery disclosed in this embodiment is applicable to various battery-powered devices. These devices can include mobile phones, portable devices, laptops, electric vehicles, electric cars, ships, spacecraft, electric toys, and power tools, etc. For example, spacecraft include airplanes, rockets, space shuttles, and spacecraft; electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys; and power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers. This disclosure does not impose any particular limitation on the aforementioned power devices. The battery can also be used to power vehicles and other electrical devices, for example, to provide power for vehicle operation or propulsion.

[0107] Figure 1 This is a structural schematic diagram of some embodiments of the electrical device according to the present disclosure. For convenience, a vehicle is used as an example for explanation. The vehicle 50 can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle, and the new energy vehicle can be a pure electric vehicle or a hybrid vehicle, etc. A battery 40 can be installed at the bottom, front, or rear of the vehicle 50.

[0108] Battery 40 can be used to power vehicle 50. For example, battery 40 can serve as the operating power source for vehicle 50's electrical system, such as meeting the power requirements for starting, navigation, and operation of vehicle 50. Battery 40 can not only serve as the operating power source for vehicle 50, but also as the driving power source for vehicle 50, replacing or partially replacing fuel or natural gas to provide propulsion for vehicle 50.

[0109] The interior of vehicle 50 may also house axles, wheels, a motor, and a controller. The controller controls the power supply from battery 40 to the motor. For example, when vehicle 50 uses battery 40 as its driving power source, battery 40 replaces or partially replaces fuel or natural gas to provide the motor with the power needed for constant speed and acceleration. The motor drives the axle to rotate, thereby rotating the wheels.

[0110] Figure 2 This is an exploded schematic diagram of some embodiments of the battery according to the present disclosure. Figure 3 This is a schematic diagram showing the connection of multiple battery cells according to some embodiments of the battery disclosed herein.

[0111] refer to Figure 2 In some embodiments, the battery 40 includes a housing 41, a cover 42 covering the opening side of the housing 41, and one or more battery cells 30 disposed in the housing 41. The housing 41 and the cover 42 provide housing space for the battery cells 30 and provide functions such as cooling, sealing and impact protection, and can also prevent liquids or other foreign objects from adversely affecting the charging, discharging or safety of the battery cells.

[0112] The box body 41 and the lid 42 can be of various shapes, such as cuboids or cylinders. The box body 41 can be a hollow structure open on one side, and the lid 42 can be a plate-like structure. When the lid 42 closes onto the open side of the box body 41, it forms an internal storage space. In another embodiment, the box body 41 is a hollow structure open on one side, and the lid 42 is also a hollow structure open on one side. When the open side of the lid 42 closes onto the open side of the box body 41, it forms an internal storage space.

[0113] refer to Figure 2 and Figure 3 The individual battery cells 30 are electrically connected, such as in series, parallel, or a combination thereof, to achieve the required electrical performance parameters of the battery 40. A combination thereof refers to multiple battery cells 30 being connected in both series and parallel configurations. Adjacent battery cells 30 can be electrically connected via busbars 43. Multiple battery cells 30 can be arranged in rows, and one or more rows of battery cells 30 can be installed within the housing 41 as needed.

[0114] In some embodiments, the individual battery cells 30 of the battery 40 can be arranged along at least one of the length and width directions of the housing 41. At least one row or column of battery cells 30 can be provided as needed. Alternatively, one or more layers of battery cells 30 can be provided along the height direction of the battery 40 as required.

[0115] In some embodiments, multiple battery cells 30 may first be connected in series, parallel, or in a mixed manner to form a battery module, and then the multiple battery modules may be connected in series, parallel, or in a mixed manner to form a whole, which is then housed within the housing 41. In other embodiments, all battery cells 30 are directly connected in series, parallel, or in a mixed manner, and then the whole consisting of all battery cells 30 is housed within the housing.

[0116] Figure 4 This is an exploded view of some embodiments of the battery cell according to the present disclosure. Figure 5 This is a schematic longitudinal section diagram of a battery cell according to some embodiments of the present disclosure via a winding shaft CL. Figure 6 This is a schematic cross-sectional view of the winding structure according to some embodiments of the electrode assembly of this disclosure. Figure 7 This is an exploded schematic diagram of the electrode assembly and conductive elements in some embodiments of the battery cell according to this disclosure.

[0117] refer to Figures 3 to 7 In some embodiments, the battery cell 30 includes an electrode assembly 10, a first conductive element 21, and a second conductive element 22. The electrode assembly 10 includes a first electrode 11, a second electrode 12, and a separator 13. The first electrode 11 and the second electrode 12 have opposite polarities. The separator 13 is located between the first electrode 11 and the second electrode 12. The first electrode 11, the second electrode 12, and the separator 13 are wound along the winding direction wd to form a winding structure 100.

[0118] exist Figure 6 In the winding structure 100, the electrode coils formed by the first electrode 11 and the second electrode 12 can be arranged alternately from the outside to the inside, at least partially. The separator 13 can be disposed between the first electrode 11 and the second electrode 12 in the form of a separator membrane.

[0119] The first electrode 11 may include a first current collector substrate 11A and a plurality of first tabs 11B. The plurality of first tabs 11B are connected to the first current collector substrate 11A and are arranged at intervals along the winding direction wd. At least a portion of the plurality of first tabs 11B are bent at the end of the winding structure 100 to form a first tab stack structure 111.

[0120] The second electrode 12 may include a second current collector substrate 12A and a plurality of second electrodes 12B. The plurality of second electrodes 12B are connected to the second current collector substrate 12A and are arranged at intervals along the winding direction wd. At least a portion of the plurality of second electrodes 12B is bent at the end of the winding structure 100 to form a second electrode stack structure 121.

[0121] The first conductive element 21 is welded to the first tab stack structure 111, and the second conductive element 22 is welded to the second tab stack structure 121. The welding of the conductive elements to the tab stack structure can be carried out by means of laser or the like, and the corresponding welding area is a liquid metal part that has been heated and melted into a certain geometric shape, i.e., the weld pool.

[0122] refer to Figure 4 and Figure 5 In some embodiments, the battery cell 30 may further include a housing 31 and electrode terminals 32. The housing 31 has a cavity for accommodating the electrode assembly 10, the first conductive element 21, and the second conductive element 22. The electrode terminals 32 are disposed on the wall of the housing 31 and are electrically connected to the first conductive element 21 or the second conductive element 22.

[0123] In addition to accommodating the electrode assembly 10, the cavity of the outer casing 31 can also accommodate the electrolyte. The shape of the outer casing 31 can be determined according to the shape of one or more electrode assemblies 10 contained in the cavity, for example, the shape of the outer casing 31 can be a hollow cuboid, a hollow cube, or a hollow cylinder.

[0124] exist Figure 4 and Figure 5 In this design, the outer casing 31 may include a housing 311 and an end cap 312. The housing 311 is a hollow structure with an opening 311A ​​at one or both ends, and its material can be one or more, such as copper, iron, aluminum, steel, aluminum alloy, plastic, etc. The end cap 312 can be made of metal or non-metal and can be fixedly connected to the housing 311 by welding, bonding or fastener connection.

[0125] One end of the housing 311 has an opening 311A, and an end cap 312 covers the opening 311A. Figure 5 In this design, the housing 311 may include a side wall 311B and a bottom wall 311C. The side wall 311B surrounds the outer side of the electrode assembly 10, and the bottom wall 311C is disposed opposite to the opening 311A. The wall portion of the housing 31 is either the end cap 312 or the bottom wall 311C. Accordingly, the electrode terminal 32 may be disposed on the end cap 312 or on the bottom wall 311C.

[0126] For a cylindrical battery cell, the housing 311 can be a hollow cylindrical structure with an opening 311A ​​at one end, and the end cap 312 can be a disc-shaped structure that matches the opening 311A. The electrode terminals 32 can be disposed on the bottom wall 311C of the housing 311 on the side away from the end cap 312.

[0127] exist Figure 4 In the middle, the bottom wall 311C may be provided with a through hole 311D. (Reference) Figure 5Electrode terminals 32 can be disposed on the through hole 311D via electrode leads 34 and the first insulating member 33. Electrode leads 34 may at least partially protrude from the outer surface of the bottom wall 311C to facilitate passage of the busbar 43 (e.g., Figure 3 (As shown) to achieve electrical connection between different battery cells 30. The first insulating member 33 is used to insulate the electrode lead-out portion 34 from the housing 311, and can be made of rubber or plastic. Optionally, openings are provided at both ends of the housing, and both are covered by end caps, and the electrode lead-out portion and electrode terminals can be provided on the end caps.

[0128] refer to Figure 4 and Figure 5 A pressure relief component 35 may be provided on the end cap 312. A pressure relief component is an element or part that is activated to release internal pressure or temperature when the internal pressure or temperature of a battery cell reaches a predetermined threshold. This threshold design varies depending on design requirements. The threshold may depend on one or more materials of the positive electrode, negative electrode, electrolyte, and separator in the battery cell. The pressure relief component can take the form of an explosion-proof valve, gas valve, pressure relief valve, or safety valve, and may specifically employ pressure-sensitive or temperature-sensitive elements or structures. That is, when the internal pressure or temperature of the battery cell reaches the predetermined threshold, the pressure relief component actuates or a weak structure within the pressure relief component is damaged, thereby forming an opening or channel for the release of internal pressure or temperature.

[0129] The emissions from individual battery cells mentioned here include, but are not limited to: electrolyte, dissolved or broken positive and negative electrode plates, fragments of the separator, high-temperature and high-pressure gases generated by the reaction (such as CH4, CO and other combustible gases), flames, etc.

[0130] refer to Figure 5 and Figure 7 In some embodiments, in the first direction d1, the first tab stack structure 111 and the second tab stack structure 121 are located at opposite ends of the winding structure 100. For the cylindrical winding structure 100, the first direction d1 is parallel to the extension direction of the winding axis CL of the winding structure 100.

[0131] Accordingly, the first conductive element 21 and the second conductive element 22 are located on both sides of the electrode assembly 10 along the first direction d1, and are respectively welded to the first tab stack structure 111 and the second tab stack structure 121 at the ends of both sides of the electrode assembly 10, and are also respectively welded to the electrode lead-out portion 34 and the end cap 312. The first conductive element 21 and the second conductive element 22 can serve as current collectors to realize the electrical connection between the electrode assembly 10 and the electrode terminal 32, and the electrical connection between the electrode assembly 10 and structures such as the end cap 312.

[0132] At least one of the first conductive element 21 and the second conductive element 22 can be a metallic conductor, such as copper, iron, aluminum, steel, aluminum alloy, etc. In some embodiments, at least one of the first conductive element 21 and the second conductive element 22 may include a current collector, or may include other structures.

[0133] Figure 8 This is an exploded schematic diagram of the electrode assembly and conductive elements in some other embodiments of the battery cell according to this disclosure. Figure 9 and Figure 10 They are Figure 8 A schematic diagram of the assembly structure and cross-section of the intermediate conductive component.

[0134] refer to Figure 8 , Figure 9 and Figure 10 In some embodiments, in the first direction d1, the first tab stack structure 111 and the second tab stack structure 121 are both located on the same side end of the winding structure 100. Correspondingly, a plurality of first tabs 11B and a plurality of second tabs 12B are distributed on the same end of the winding structure 100, and the first tab stack structure 111 and the second tab stack structure 121 obtained by bending and stacking can be distributed at different angle ranges on this side end. The first conductive element 21 and the second conductive element 22 are also both disposed on the same side of the winding structure 100 and are respectively welded to the first tab stack structure 111 and the second tab stack structure 121.

[0135] refer to Figure 8 The first conductive element 21 and the second conductive element 22 can both be fan-shaped. Furthermore, to insulate the first conductive element 21 and the second conductive element 22 from each other, a second insulating element 23 can be provided at this end of the winding structure. Both the first conductive element 21 and the second conductive element 22 are assembled with the second insulating element 23. Figure 8 The assembled structure shown is welded to the first tab stack structure 111 and the second tab stack structure 121.

[0136] refer to Figure 9 and Figure 10 The second insulating member 23 may have a hollow portion and an opening extending along the first direction d1, wherein the opening is used to accommodate the first conductive member 21, and the hollow portion accommodates the second conductive member 22. The second insulating member 23 may be made of rubber or plastic.

[0137] Figure 11 This is a schematic diagram of the electrode plates and tabs in an unfolded state according to some embodiments of the electrode assembly of this disclosure. Figure 12 This is a schematic diagram of the electrode plates and tabs in an unfolded state according to other embodiments of the electrode assembly of this disclosure. Figure 13 This is a schematic cross-sectional view of the electrode stack structure and the conductive element welded together in some embodiments of the electrode assembly according to this disclosure.

[0138] Figure 11 In an embodiment where multiple first tabs 11B and multiple second tabs 12B are distributed at opposite ends of the winding structure 100, Figure 12 This corresponds to an embodiment where multiple first tabs 11B and multiple second tabs 12B are distributed at the same end of the winding structure 100. Figure 11 and Figure 12 In the middle, the second direction d2 is parallel to the length direction of the first electrode 11 or the second electrode 12, and is also equivalent to the winding direction wd after unfolding. The first direction d1 is parallel to the winding axis CL of the winding structure 100, and is also parallel to the width direction of the first electrode 11 or the second electrode 12.

[0139] refer to Figure 11 and Figure 12 In a first direction d1 parallel to the extension direction of the winding axis CL of the winding structure 100, the bending positions 11f of the plurality of first tabs 11B are located on the side of the isolation member 13 away from the first current collector substrate 11A, and the bending positions 12f of the plurality of second tabs 12B are located on the side of the isolation member 13 away from the second current collector substrate 12A.

[0140] exist Figure 11 and Figure 12 In the diagram, the bending positions of the first tab 11B and the second tab 12B are shown by dashed lines. For embodiments where multiple tabs are cut from the current collector substrate using methods such as laser cutting, the bending position 11f of the multiple first tabs 11B can be the cut root 11r of the multiple first tabs 11B, or a position closer to the tab top 11t of the first tab 11B than the cut root 11r; similarly, the bending position 12f of the multiple second tabs 12B can be the cut root 12r of the multiple second tabs 12B, or a position closer to the tab top 12t of the second tab 12B than the cut root 12r.

[0141] At least a portion of a plurality of first tabs 11B are bent at the end of the winding structure 100 to form a first tab stack structure 111, and at least a portion of a plurality of second tabs 12B are bent at the end of the winding structure 100 to form a second tab stack structure 121.

[0142] The bending positions 11f of the plurality of first tabs 11B can have gaps with the spacer 13 in the first direction d1. This reduces the risk of heat from the stacked structure of the first tabs being conducted to the spacer 13 during welding, causing burns to the spacer 13. Accordingly, the minimum distance between the bending positions 11f of the plurality of first tabs 11B and the spacer 13 in the first direction d1 is defined as the first minimum distance L1.

[0143] The bending positions 12f of the plurality of second tabs 12B can have gaps with the spacer 13 in the first direction d1. This reduces the risk of heat from the stacked structure of the second tabs being conducted to the spacer 13 during welding, causing burns to the spacer 13. Accordingly, the minimum distance between the bending positions 12f of the plurality of second tabs 12B and the spacer 13 in the first direction d1 is defined as the second minimum distance L2.

[0144] When the bending position 11f of the plurality of first tabs 11B is the location where the tabs are cut in the portion of the first current collector substrate 11A not covered by the first active material layer 11C, the first minimum distance L1 is the minimum distance between the cut roots 11r of the plurality of first tabs 11B and the spacer 13 in the first direction d1. When the bending position 12f of the plurality of second tabs 12B is the location where the tabs are cut in the portion of the current collector substrate not covered by the active material layer, the second minimum distance L2 is the minimum distance between the cut roots 12r of the plurality of second tabs 12B and the spacer 13 in the first direction d1.

[0145] In some embodiments, the melting point of the materials of the plurality of first tabs 11B is lower than the melting point of the materials of the plurality of second tabs 12B, and the first minimum distance L1 is less than or equal to the second minimum distance L2. For example, when the first tabs 11B are made of aluminum with a melting point of 660°C or copper with a melting point of 1083°C, and the second tabs 12B are made of aluminum with a melting point of 660°C, the first minimum distance L1 in this embodiment can be set to be less than or equal to the second minimum distance L2.

[0146] For a battery cell embodiment where the melting point of the first tab 11B material is lower than that of the second tab 12B material, the second tab 12B material with the higher melting point requires greater welding heat to form a weld pool. Consequently, the second tab stack structure 121 generates more heat during welding. When the heat generated by the second tab stack structure 121 is high, there is a risk of burns from thermal radiation even if the spacer 13 is not in contact with the second tab stack structure 121. Therefore, by ensuring that the second minimum distance L2 is not lower than the first minimum distance L1, the risk of burns to the spacer 13 corresponding to the second tab stack structure 121, as well as the risk of burns from thermal radiation due to the spacer 13 being too close to the second tab stack structure 121, can be reduced.

[0147] In some embodiments, the melting point of the materials of the plurality of first tabs 11B is greater than the melting point of the materials of the plurality of second tabs 12B, and the second minimum distance L2 is less than or equal to the first minimum distance L1. For example, when the first tabs 11B are made of copper with a melting point of 1083°C and the second tabs 12B are made of aluminum with a melting point of 660°C, the second minimum distance L2 in this embodiment can be set to be less than or equal to the first minimum distance L1.

[0148] For a battery cell embodiment where the melting point of the first tab 11B material is greater than that of the second tab 12B material, the first tab 11B material with the larger melting point requires greater welding heat to form a weld pool. Consequently, the first tab stack structure 111 generates more heat during welding. When the heat generated by the first tab stack structure 111 is high, there is a risk of burns from thermal radiation even if the spacer 13 is not in contact with the first tab stack structure 111. Therefore, by ensuring that the first minimum distance L1 is not less than the second minimum distance L2, the risk of burns to the spacer portion corresponding to the first tab stack structure 111, as well as the risk of burns from thermal radiation due to the spacer being too close to the first tab stack structure 111, can be reduced.

[0149] refer to Figure 11 and Figure 12 In the first direction d1, there is a third minimum distance L3 between the bending position 11f of the plurality of first electrode tabs 11B and the top 11t of the electrode tabs of the plurality of first electrode tabs 11B, and there is a fourth minimum distance L4 between the bending position 12f of the plurality of second electrode tabs 12B and the top 12t of the electrode tabs of the plurality of second electrode tabs 12B.

[0150] When the bending position 11f of the plurality of first tabs 11B is the location where the tabs are cut in the portion of the first current collector substrate 11A not covered by the first active material layer 11C, the third minimum distance L3 is the minimum distance between the cut root 11r of the plurality of first tabs 11B and the tab top 11t of the plurality of first tabs 11B in the first direction d1, which is equivalent to the height of the first tab 11B. When the bending position 12f of the plurality of second tabs 12B is the location where the tabs are cut in the portion of the current collector substrate not covered by the active material layer, the fourth minimum distance L4 is the minimum distance between the cut root 12r of the plurality of second tabs 12B and the tab top 12t of the plurality of second tabs 12B in the first direction d1, which is equivalent to the height of the second tab 12B.

[0151] Figure 13 This is a schematic cross-sectional view of the electrode stack structure and the conductive element welded together in some embodiments of the electrode assembly according to this disclosure.

[0152] refer to Figure 11 , Figure 12 and Figure 13 In some embodiments, the first thickness t1 of the plurality of first tabs 11B in the thickness direction of the first tab 11B is less than the second thickness t2 of the plurality of second tabs 12B in the thickness direction of the second tab 12B, and the third minimum distance L3 is greater than or equal to the fourth minimum distance L4.

[0153] The third minimum distance L3 and the fourth minimum distance L4 represent the lengths of the first tab 11B and the second tab 12B when they are bent and participate in the stacking process, respectively. The longer the length of the tabs participating in the stacking process, the higher the degree of tab overlap. The first thickness t1 of the first tab 11B represents the thickness of a single layer of the first tab 11B, and the second thickness t2 of the second tab 12B represents the thickness of a single layer of the second tab 12B. The thicker the single-layer tab, the thicker the stacked tab structure after stacking.

[0154] For the embodiment of the battery cell 30 where the first thickness t1 is less than the second thickness t2, by making the third minimum distance L3 greater than or equal to the fourth minimum distance L4, the thicknesses of the first tab stack structure 111 and the second tab stack structure 121 can be made closer, which helps to reduce the risk of burns or scalds to the insulating part caused by the difference in welding heat when forming the welding pool mp.

[0155] In other embodiments, the first thickness t1 of the plurality of first tabs 11B in the thickness direction of the first tabs 11B is greater than the second thickness t2 of the plurality of second tabs 12B in the thickness direction of the second tabs 12B, and the third minimum distance L3 is less than or equal to the fourth minimum distance L4.

[0156] For the embodiment of the battery cell 30 with a first thickness t1 greater than the second thickness t2, by making the third minimum distance L3 less than or equal to the fourth minimum distance L4, the thicknesses of the first tab stack structure 111 and the second tab stack structure 121 can be made closer, which helps to reduce the risk of burns or scalds to the insulating part caused by the difference in welding heat when forming the welding pool mp.

[0157] In the above embodiments, the ratio A / B of the product A of the first thickness t1 and the third minimum distance L3 of the plurality of first tabs 11B in the thickness direction of the first tab 11B and the product B of the second thickness t2 and the fourth minimum distance L4 of the plurality of second tabs 12B in the thickness direction of the second tab 12B satisfies: 0.2≤A / B≤4, wherein the units of the first thickness t1, the second thickness t2, the third minimum distance L3 and the fourth minimum distance L4 are the same, for example, mm or cm.

[0158] The product A of the first thickness t1 and the third minimum distance L3 represents the stacking thickness of the first tab stack structure 111, and the product B of the second thickness t2 and the fourth minimum distance L4 represents the stacking thickness of the second tab stack structure 121. The ratio of the product A to the product B can reflect the degree of difference in the stacking thickness of the first tab stack structure 111 and the second tab stack structure 121.

[0159] If the ratio A / B is too large, the first tab stack structure 111 will be thicker, requiring higher welding power and higher welding heat during welding. This increases the risk of burns or scalds on the insulating part corresponding to the first tab stack structure 111 compared to the second tab stack structure 121.

[0160] If the ratio A / B is too small, the second tab stack structure 121 will be thicker, requiring higher welding power and higher welding heat during welding. This increases the risk of burns or scalds on the insulating part corresponding to the second tab stack structure 121 compared to the first tab stack structure 111.

[0161] Therefore, by ensuring that the ratio A / B satisfies: 0.2≤A / B≤4, the difference in stacking thickness between the first tab stack structure 111 and the second tab stack structure 121 is reduced, thereby reducing the risk of burns or scalds to the insulating parts corresponding to the first tab stack structure 111 and the second tab stack structure 121.

[0162] Furthermore, the ratio A / B can satisfy: 0.5≤A / B≤2, for example, making A / B equal to 0.5, 0.8, 1, 1.2, 1.6 or 2.

[0163] By further limiting the ratio A / B to satisfy: 0.5≤A / B≤2, the difference in stacking thickness between the first tab stack structure 111 and the second tab stack structure 121 can be further reduced, thereby more effectively reducing the risk of burns or scalds to the insulating parts corresponding to the first tab stack structure 111 and the second tab stack structure 121.

[0164] refer to Figure 13 In some embodiments, the ratio A / B of the product A of the first thickness t1 and the third minimum distance L3 of the plurality of first tabs 11B in the thickness direction of the first tab 11B and the product B of the second thickness t2 and the fourth minimum distance L4 of the plurality of second tabs 12B in the thickness direction of the second tab 12B satisfies: A / B < 1, wherein the units of the first thickness t1, the second thickness t2, the third minimum distance L3, and the fourth minimum distance L4 are the same, for example, all in mm or cm. Accordingly, the third thickness t3 of the first conductive element 21 in the first direction d1 is less than the fourth thickness t4 of the second conductive element 22 in the first direction d1.

[0165] The product A of the first thickness t1 and the third minimum distance L3 represents the stacking thickness of the first tab stacking structure 111, and the product B of the second thickness t2 and the fourth minimum distance L4 represents the stacking thickness of the second tab stacking structure 121. For battery cell embodiments where the product A is less than the product B, the second tab stacking structure 121 with a larger stacking thickness requires higher welding power for welding. However, when the laser power fluctuates, it is easy to form an excessively deep molten pool, which increases the risk of burns or scalds to the separator.

[0166] Therefore, a thicker second conductive element 22 is used to increase the fault tolerance of the welding and reduce the possibility of forming an excessively deep molten pool, thereby reducing the risk of burns or scalds on the insulating part corresponding to the second tab stack structure 121. Conversely, a thinner first conductive element 21, combined with a thinner first tab stack structure 111, allows for welding with lower power, making it easier to form a molten pool of suitable depth and further reducing the risk of burns or scalds on the insulating part corresponding to the first tab stack structure 111.

[0167] In other embodiments, the ratio A / B of the product A of the first thickness t1 and the third minimum distance L3 of the plurality of first tabs 11B in the thickness direction of the first tab 11B and the product B of the second thickness t2 and the fourth minimum distance L4 of the plurality of second tabs 12B in the thickness direction of the second tab 12B satisfies: A / B > 1, wherein the units of the first thickness t1, the second thickness t2, the third minimum distance L3, and the fourth minimum distance L4 are the same, for example, all in mm or cm. Accordingly, the third thickness t3 of the first conductive element 21 in the first direction d1 is greater than the fourth thickness t4 of the second conductive element 22 in the first direction d1.

[0168] The product A of the first thickness t1 and the third minimum distance L3 represents the stacking thickness of the first tab stacking structure 111, and the product B of the second thickness t2 and the fourth minimum distance L4 represents the stacking thickness of the second tab stacking structure 121. For the battery cell 30 embodiment where the product B is less than the product A, the first tab stacking structure 111 with a larger stacking thickness requires higher welding power for welding. However, when the laser power fluctuates, it is easy to form an excessively deep molten pool, which increases the risk of burns or scalds to the separator.

[0169] Therefore, a thicker first conductive element 21 is used to increase the fault tolerance of the welding and reduce the possibility of forming an excessively deep molten pool, thereby reducing the risk of burns or scalds on the insulating part corresponding to the first tab stack structure 111. The thinner second conductive element 22, combined with the thinner second tab stack structure 121, allows for welding with lower power, making it easier to form a molten pool of suitable depth and further reducing the risk of burns or scalds on the insulating part corresponding to the second tab stack structure 121.

[0170] Based on the aforementioned embodiments of the battery cells, refer to Figure 2 This disclosure provides a battery 40, including the battery cell 30 of any of the foregoing embodiments. Batteries using the aforementioned battery cells can effectively improve safety during use.

[0171] Based on the aforementioned battery embodiments, refer to Figure 1 This disclosure provides an electrical device including the battery 40 of any of the foregoing embodiments. Electrical devices using the aforementioned batteries can effectively improve safety during use.

[0172] In some specific embodiments, such as Figures 5-7 and Figure 11 As shown, the battery cell 30 is cylindrical and includes: an electrode assembly 10, a first conductive element 21, a second conductive element 22, a housing 31, and electrode terminals 32. The housing 31 has a cavity for accommodating the electrode assembly 10, the first conductive element 21, and the second conductive element 22. The housing 31 may include a shell 311 and an end cap 312. One end of the shell 311 has an opening 311A, and the end cap 312 covers the opening 311A. The shell 311 includes a side wall 311B and a bottom wall 311C. The side wall 311B surrounds the outside of the electrode assembly 10, and the bottom wall 311C is disposed opposite to the opening 311A. The bottom wall 311C has a through hole 311D. The electrode terminals 32 are disposed on the through hole 311D through an electrode lead-out portion 34 and a first insulating element 33.

[0173] The battery cell 30 includes an electrode assembly 10, a first conductive element 21, and a second conductive element 22. The electrode assembly 10 includes a first electrode 11, a second electrode 12, and a separator 13. The first electrode 11 and the second electrode 12 have opposite polarities. The separator 13 is located between the first electrode 11 and the second electrode 12. The first electrode 11, the second electrode 12, and the separator 13 are wound along a winding direction wd to form a cylindrical winding structure 100. The separator 13 is disposed between the first electrode 11 and the second electrode 12 in the form of a separator film.

[0174] The first electrode 11 includes a first current collector substrate 11A and a plurality of first tabs 11B. The plurality of first tabs 11B are connected to the first current collector substrate 11A and are arranged at intervals along the winding direction wd. At least a portion of the plurality of first tabs 11B are bent at the end of the winding structure 100 to form a first tab stack structure 111.

[0175] The second electrode 12 includes a second current collector substrate 12A and a plurality of second electrodes 12B. The plurality of second electrodes 12B are connected to the second current collector substrate 12A and are arranged at intervals along the winding direction wd. At least a portion of the plurality of second electrodes 12B are bent at the end of the winding structure 100 to form a second electrode stack structure 121.

[0176] The first conductive element 21 is welded to the first electrode stack structure 111 and to the electrode lead-out portion 34 to achieve electrical connection with the electrode terminal 32. The second conductive element 22 is welded to the second electrode stack structure 121 and to the end cap 312.

[0177] In the first direction d1, the first electrode stack structure 111 and the second electrode stack structure 121 are located at opposite ends of the winding structure 100. The first conductive element 21 and the second conductive element 22 are located on both sides of the electrode assembly 10 along the first direction d1.

[0178] The first electrode 11 is a positive electrode, and the materials of its first current collector substrate 11A and the first tab 11B, which is cut from the portion of the first current collector substrate 11A that is not covered by the first active material layer 11C, are both aluminum. The second electrode 12 is a negative electrode, and the materials of its second current collector substrate 12A and the second tab 12B, which is cut from the portion of the second current collector substrate 12A that is not covered by the second active material layer 12C, are both copper.

[0179] The melting point of aluminum is lower than that of copper. (Reference) Figure 11 The first minimum distance L1 is less than the second minimum distance L2. The second thickness t2 of the second tab 12B is greater than the first thickness t1 of the first tab 11B, and the third minimum distance L3 is greater than the fourth minimum distance L4.

[0180] While this disclosure has been described with reference to preferred embodiments, various modifications can be made thereto and components can be replaced with equivalents without departing from the scope of this disclosure. In particular, the technical features mentioned in the various embodiments can be combined in any manner, provided there is no structural conflict. This disclosure is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A battery cell (30), comprising: The electrode assembly (10) includes a first electrode (11), a second electrode (12), and a separator (13). The first electrode (11) and the second electrode (12) have opposite polarities. The separator (13) is located between the first electrode (11) and the second electrode (12). The first electrode (11), the second electrode (12), and the separator (13) are wound along a winding direction (wd) to form a winding structure (100). The first electrode (11) includes a plurality of first tabs (11B) that are bent at the end of the winding structure (100) to form a first tab stack structure (111). The second electrode (12) includes a plurality of second tabs (12B) that are bent at the end of the winding structure (100) to form a second tab stack structure (121). The first conductive element (21) is welded to the first electrode stack structure (111); and The second conductive element (22) is welded to the second electrode stack structure (121). Wherein, in a first direction (d1) parallel to the extension direction of the winding axis of the winding structure (100), at least one of the bending positions (11f) of the plurality of first tabs (11B) and the bending positions (12f) of the plurality of second tabs (12B) has a gap with the spacer (13) in the first direction (d1); in the first direction (d1), there is a third minimum distance L3 between the bending positions (11f) of the plurality of first tabs (11B) and the tops (11t) of the tabs of the plurality of first tabs (11B), and there is a fourth minimum distance L4 between the bending positions (12f) of the plurality of second tabs (12B) and the tops (12t) of the tabs of the plurality of second tabs (12B); Wherein, the first thickness t1 of the plurality of first electrodes (11B) in the thickness direction of the first electrodes (11B) is less than the second thickness t2 of the plurality of second electrodes (12B) in the thickness direction of the second electrodes (12B), and the third minimum distance L3 is greater than or equal to the fourth minimum distance L4; or, the first thickness t1 of the plurality of first electrodes (11B) in the thickness direction of the first electrodes (11B) is greater than the second thickness t2 of the plurality of second electrodes (12B) in the thickness direction of the second electrodes (12B), and the third minimum distance L3 is less than or equal to the fourth minimum distance L4.

2. The battery cell (30) according to claim 1, wherein, The bending position (11f) of the plurality of first electrodes (11B) is the cut root (11r) of the plurality of first electrodes (11B), and / or, the bending position (12f) of the plurality of second electrodes (12B) is the cut root (12r) of the plurality of second electrodes (12B).

3. The battery cell (30) according to claim 1, wherein, The ratio A / B of the product A of the first thickness t1 and the third minimum distance L3 of the plurality of first tabs (11B) in the thickness direction of the first tab (11B) and the product B of the second thickness t2 and the fourth minimum distance L4 of the plurality of second tabs (12B) in the thickness direction of the second tab (12B) satisfies: 0.2≤A / B≤4, wherein the units of the first thickness t1, the second thickness t2, the third minimum distance L3, and the fourth minimum distance L4 are the same.

4. The battery cell (30) according to claim 3, wherein, The ratio A / B satisfies: 0.5 ≤ A / B ≤ 2.

5. The battery cell (30) according to claim 1, wherein, The ratio A / B of the product A of the first thickness t1 and the third minimum distance L3 of the plurality of first electrodes (11B) in the thickness direction of the first electrode (11B) and the product B of the second thickness t2 and the fourth minimum distance L4 of the plurality of second electrodes (12B) in the thickness direction of the second electrode (12B) satisfies: A / B<1, wherein the units of the first thickness t1, the second thickness t2, the third minimum distance L3 and the fourth minimum distance L4 are the same, and the third thickness t3 of the first conductive element (21) in the first direction (d1) is less than the fourth thickness t4 of the second conductive element (22) in the first direction (d1).

6. The battery cell (30) according to claim 1, wherein, The ratio A / B of the product A of the first thickness t1 and the third minimum distance L3 of the plurality of first electrodes (11B) in the thickness direction of the first electrode (11B) and the product B of the second thickness t2 and the fourth minimum distance L4 of the plurality of second electrodes (12B) in the thickness direction of the second electrode (12B) satisfies: A / B>1, wherein the units of the first thickness t1, the second thickness t2, the third minimum distance L3 and the fourth minimum distance L4 are the same, and the third thickness t3 of the first conductive element (21) in the first direction (d1) is greater than the fourth thickness t4 of the second conductive element (22) in the first direction (d1).

7. The battery cell (30) according to any one of claims 1 to 6, wherein, In the first direction (d1), the first tab stack structure (111) and the second tab stack structure (121) are both located at the same end of the winding structure (100).

8. The battery cell (30) according to any one of claims 1 to 6, wherein, In the first direction (d1), the first tab stack structure (111) and the second tab stack structure (121) are located at opposite ends of the winding structure (100).

9. The battery cell (30) according to any one of claims 1 to 6, further comprising: The housing (31) has a chamber for accommodating the electrode assembly (10), the first conductive element (21), and the second conductive element (22); and Electrode terminals (32) are disposed on the wall of the housing (31) and electrically connected to the first conductive element (21) or the second conductive element (22).

10. The battery cell (30) according to claim 9, wherein, The outer casing (31) includes a housing (311) and an end cap (312). One end of the housing (311) has an opening (311A), and the end cap (312) covers the opening (311A). The housing (311) includes a side wall (311B) and a bottom wall (311C). The side wall (311B) surrounds the outside of the electrode assembly (10), and the bottom wall (311C) is disposed opposite to the opening (311A). The wall of the outer casing (31) is either the end cap (312) or the bottom wall (311C).

11. The battery cell (30) according to any one of claims 1 to 6, wherein, The first electrode (11) further includes a first current collector substrate (11A), and the plurality of first electrode tabs (11B) are connected to the first current collector substrate (11A) and are arranged at intervals along the winding direction (wd). In the first direction (d1), the bending position (11f) of the plurality of first electrode tabs (11B) is located on the side of the separator (13) away from the first current collector substrate (11A). The second electrode (12) further includes a second current collector substrate (12A), the plurality of second electrodes (12B) are connected to the second current collector substrate (12A) and are arranged at intervals along the winding direction (wd). In the first direction (d1), the bending position (12f) of the plurality of second electrodes (12B) is located on the side of the separator (13) away from the second current collector substrate (12A).

12. A battery (40), comprising: The battery cell (30) according to any one of claims 1 to 11.

13. An electrical appliance, comprising: The battery (40) according to claim 12.

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