Battery monomer, battery device and electric device

Abstract

The embodiment of the utility model provides a battery monomer, a battery device and a power utilization device. Each battery monomer comprises a shell, an electrode assembly and a supporting piece; the electrode assembly is arranged in the shell, the electrode assembly is of a winding type structure, the electrode assembly comprises first pole pieces, the first pole piece on the innermost ring comprises a first straight section, a first corner section and a second straight section, one end of the first straight section is the winding starting end of the first pole piece, and the first corner section is connected with the first straight section and the second straight section; the supporting piece is arranged between the first straight section and the second straight section in the thickness direction of the electrode assembly. According to the technical scheme provided by the invention, the reliability of the battery monomer can be improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of battery device, in particular to a battery monomer, a battery device and an electric device. BACKGROUND

[0002] Energy saving and emission reduction is the key to the sustainable development of the automobile industry. Electric vehicles have become an important part of the sustainable development of the automobile industry due to their energy saving and environmental protection advantages. For electric vehicles, battery device technology is an important factor for their development.

[0003] In the manufacturing process of the battery device, the reliability of the battery device is a problem that cannot be ignored. Therefore, how to improve the reliability of the battery device is a technical problem that needs to be solved in the battery device technology. CONTENT OF THE UTILITY MODEL

[0004] The present application provides a battery monomer, a battery device and an electric device, which can improve the reliability of the battery monomer.

[0005] The present application is realized by the following technical scheme:

[0006] In a first aspect, the present application provides a battery monomer, which comprises a shell, an electrode assembly and a support; the electrode assembly is arranged in the shell, the electrode assembly is of a winding type structure, and the electrode assembly comprises a first tab; the first tab of the innermost circle comprises a first flat section, a first corner section and a second flat section; one end of the first flat section is the winding start end of the first tab, and the first corner section connects the first flat section and the second flat section; and the support is arranged between the first flat section and the second flat section in the thickness direction of the electrode assembly.

[0007] According to the battery monomer of the present application, the support is arranged between the first flat section and the second flat section of the first tab of the innermost circle, so that when the electrode assembly is pre-pressed, the support can share the pressure received by the first flat section and the second flat section when they are folded, disperse the stress received by the first corner section, and reduce the risk of stress concentration of the first corner section; therefore, when the electrode assembly is pre-pressed and shaped, the risk of opening of the electrode assembly can be reduced by increasing the pre-pressing pressure, and the first corner section is less likely to crack, so that the battery monomer has high reliability, thereby improving the reliability of the battery device composed of the battery monomer.

[0008] According to some embodiments of the present application, the support is in the form of a sheet, and the thickness direction of the support is parallel to the thickness direction of the electrode assembly.

[0009] In the above scheme, the support is in the form of a sheet, and the support can occupy a smaller space while meeting the support requirement.

[0010] According to some embodiments of the present application, the thickness of the support is H, satisfying 1mm≤H≤5mm.

[0011] In the above scheme, the thickness H of the support satisfies the above relationship (1mm≤H≤5mm), the support has a higher support strength, which facilitates reducing stress concentration of the first corner section, and the support occupies a smaller space and has a smaller impact on the opening of the electrode assembly.

[0012] According to some embodiments of the present application, 1mm≤H≤3mm.

[0013] In the above scheme, the thickness H of the support satisfies the above relationship (1mm≤H≤3mm), which further reduces the space occupation of the support and the impact on the opening of the electrode assembly while satisfying the support strength.

[0014] According to some embodiments of the present application, the first tab of the innermost circle further comprises a second corner section connected to one end of the second flat section away from the first corner section; in the first direction, the support has a first end close to the first corner section and a second end away from the first corner section, the first direction, the thickness direction of the electrode assembly and the winding axis direction of the electrode assembly are perpendicular to each other; in the first direction, the distance between the first end and the outer side vertex of the first corner section is L1, and the distance between the second end and the outer side vertex of the second corner section is L2, satisfying 0<L1≤15mm and 0<L2≤15mm.

[0015] In the above scheme, the distance L1 between the first end and the outer side vertex of the first corner section and the distance L2 between the second end and the outer side vertex of the second corner section satisfy the above relationship (0<L1≤15mm and 0<L2≤15mm), the support is provided corresponding to the first corner section and the second corner section, and when the electrode assembly is pre-pressed, the support can absorb the pressure when the first flat section and the second flat section are folded, can disperse the stress on the first corner section and the second corner section, reduce the stress concentration of the first corner section and the second corner section, and reduce the risk of cracking of the first corner section and the second corner section.

[0016] According to some embodiments of the present application, 2mm≤L1≤10mm and 2mm≤L2≤10mm.

[0017] In the above scheme, the distance L1 between the first end and the outer side vertex of the first corner section and the distance L2 between the second end and the outer side vertex of the second corner section satisfy the above relationship (2mm≤L1≤10mm and 2mm≤L2≤10mm), the first end is arranged close to the first corner section, and the second end is arranged close to the second corner section, which further shares the stress of the first corner section and the second corner section and reduces the risk of cracking of the first corner section and the second corner section.

[0018] According to some embodiments of the present application, the first pole piece of the innermost turn further comprises a second corner section connected to one end of the second flat section away from the first corner section; in the first direction, the size of the support is W1, the distance between the outer side vertex of the first corner section and the outer side vertex of the second corner section is W2, and 0.5≤W1 / W2<1 is satisfied, and the first direction, the thickness direction of the electrode assembly and the winding axis direction of the electrode assembly are perpendicular to each other.

[0019] In the above scheme, the size W1 of the support in the first direction and the distance W2 between the outer side vertex of the first corner section and the outer side vertex of the second corner section satisfy the above relationship (0.5≤W1 / W2<1), the support has a larger overlapping area with the second flat section, and the support can absorb more pressure when the electrode assembly is pre-pressed, which is beneficial to disperse the stress on the first corner section and reduce the risk of cracking of the first corner section.

[0020] According to some embodiments of the present application, 0.9≤W1 / W2<1.

[0021] In the above scheme, the size W1 of the support in the first direction and the distance W2 between the outer side vertex of the first corner section and the outer side vertex of the second corner section satisfy the above relationship (0.9≤W1 / W2<1), the size of the support in the first direction can be designed to be larger, which can correspond to the two corner sections (the first corner section and the second corner section) of the first pole piece of the innermost turn in the first direction, facilitate the dispersion of the stress of the two corner sections of the first pole piece of the innermost turn, and be beneficial to reduce the risk of cracking of the two corner sections of the first pole piece of the innermost turn.

[0022] According to some embodiments of the present application, the support comprises two sub-supports, and the two sub-supports are arranged in the first direction with a spacing, and the first direction, the thickness direction of the electrode assembly and the winding axis direction of the electrode assembly are perpendicular to each other.

[0023] In the above scheme, the two sub-supports are arranged in the first direction with a spacing, which can absorb the pressure received when the first flat section and the second flat section are folded in two positions in the first direction, facilitate the dispersion of the stress of the corner section of the first pole piece of the innermost turn, and be beneficial to reduce the risk of cracking of the corner section of the first pole piece of the innermost turn.

[0024] According to some embodiments of the present application, in the first direction, the size of the sub-support is W3, and 5mm≤W3≤50mm is satisfied.

[0025] In the above scheme, the size W3 of the sub-support in the first direction satisfies the above relationship (5mm≤W3≤50mm). On the one hand, the sub-support has a large overlap area with the first flat section and the second flat section, which can facilitate the absorption of the pressure received by the first flat section and the second flat section when they are folded, facilitate the dispersion of the stress received by the two corner sections of the first pole piece of the innermost circle, and be conducive to reducing the risk of cracking of the two corner sections of the first pole piece of the innermost circle. On the other hand, the size of the sub-support in the first direction can be small, so as to facilitate the reduction of the material of the sub-support and the reduction of the cost.

[0026] According to some embodiments of the present application, 10mm≤W3≤30mm.

[0027] In the above scheme, the size W3 of the sub-support in the first direction satisfies the above relationship (10mm≤W3≤30mm). On the one hand, when W3≥10mm, the sub-support has high strength and can absorb the pressure received by the first flat section and the second flat section when they are folded. On the other hand, when W3≤30mm, the size of the sub-support in the first direction is small, which further reduces the material of the sub-support and reduces the cost.

[0028] According to some embodiments of the present application, the first pole piece includes a first main body part and a first tab, the first tab extending from an end of the first main body part in the winding axis direction of the electrode assembly; in the winding axis direction of the electrode assembly, the size of the first main body part is K1, and the size of the support is K2, which satisfies 0.5≤K2 / K1≤1.

[0029] In the above scheme, K1 / K2 satisfies the above relationship, so that the support and the first main body part have a large overlap area in the winding axis direction of the electrode assembly, so as to facilitate the support of the first flat section and the second flat section by the support and facilitate the absorption of the pressure received by the first flat section and the second flat section when they are folded.

[0030] According to some embodiments of the present application, 0.8≤K2 / K1≤1.

[0031] In the above scheme, when 0.8≤K2 / K1, the overlap area of the support and the first main body part in the winding axis direction of the electrode assembly can be further increased, so as to facilitate the support of the first flat section and the second flat section by the support and facilitate the absorption of the pressure received by the first flat section and the second flat section when they are folded.

[0032] According to some embodiments of the present application, the support is an insulating sheet.

[0033] In the above scheme, the support is an insulating sheet, which can reduce the risk of positive and negative contact short circuit.

[0034] According to some embodiments of the present application, the density of the support is 0.8g / cm3 ~2.2g / cm 3 .

[0035] In the above scheme, the density of the support satisfies the above relationship (0.8g / cm 3 ~2.2g / cm 3 ), the weight of the support is lighter, and the influence of the support on the weight energy density of the battery monomer is reduced.

[0036] According to some embodiments of the application, the material of the support is polytetrafluoroethylene, polyvinyl chloride, polypropylene or polycarbonate.

[0037] In the above scheme, the material of the support is polytetrafluoroethylene, polyvinyl chloride, polypropylene or polycarbonate, which has good insulation performance and is corrosion resistant, and has a long service life.

[0038] According to some embodiments of the application, the electrode assembly includes a second pole piece, the second pole piece is opposite in polarity to the first pole piece, the second pole piece of the innermost circle includes a third flat section, a third corner section and a fourth flat section, one end of the third flat section is the winding start end of the second pole piece, the third corner section connects the third flat section and the fourth flat section; along the thickness direction of the electrode assembly, the first flat section and the second flat section are located between the third flat section and the fourth flat section, and the first corner section is located inside the third corner section.

[0039] In the above scheme, the second pole piece is opposite in polarity to the first pole piece, the first flat section and the second flat section are located between the third flat section and the fourth flat section, and the first corner section is located inside the third corner section. When the electrode assembly is wound and formed, the first pole piece enters the winding before the second pole piece, the first pole piece of the innermost circle is located inside the second pole piece of the innermost circle, and the support is arranged between the first flat section and the second flat section, so as to form a support between the first flat section and the second flat section, absorb the pressure received when the first flat section and the second flat section are folded, and disperse the stress received by the first corner section.

[0040] According to some embodiments of the application, the electrode assembly includes a second pole piece, the second pole piece is opposite in polarity to the first pole piece, the second pole piece of the innermost circle includes a third flat section, a third corner section and a fourth flat section, one end of the third flat section is the winding start end of the second pole piece, the third corner section connects the third flat section and the fourth flat section; along the thickness direction of the electrode assembly, the first flat section is located between the third flat section and the fourth flat section, the third flat section is located between the first flat section and the second flat section, and the support is arranged between the first flat section and the third flat section.

[0041] In the above scheme, the innermost circle of the first pole piece and the innermost circle of the second pole piece are arranged in a plug-in manner, the first flat section of the innermost circle of the first pole piece can be arranged as a double-sided active material coating area, and the third flat section of the innermost circle of the second pole piece can be arranged as a double-sided active material coating area, so that the battery monomer has a higher energy density. At the same time, the support is arranged between the first flat section and the third flat section to form a support between the first flat section and the third flat section, the support can absorb the pressure received by the first flat section and the third flat section when they are folded, facilitate the dispersion of the stress received by the first corner section and the third corner section, reduce the risk of stress concentration of the first corner section and the third corner section, thereby reducing the risk of cracking of the first corner section and the third corner section, and further improving the reliability of the battery monomer.

[0042] In a second aspect, the embodiments of the present application also provide a battery device, which comprises the battery monomer according to any of the above embodiments.

[0043] In a third aspect, the embodiments of the present application also provide a power consumption device, which comprises the battery device according to any of the above embodiments.

[0044] The above description is only a summary of the technical solutions of the present application. In order to more clearly understand the technical means of the present application, the embodiments of the present application can be implemented according to the content of the specification, and in order to make the above and other purposes, characteristics and advantages of the present application more obvious and easy to understand, the following specific embodiments of the present application are described. BRIEF DESCRIPTION OF DRAWINGS

[0045] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor.

[0046] Figure 1 The structural schematic diagram of the vehicle provided by some embodiments of the present application is shown in the figure;

[0047] Figure 2 The structural exploded schematic diagram of the battery device provided by some embodiments of the present application is shown in the figure;

[0048] Figure 3 The structural exploded schematic diagram of the battery monomer provided by some embodiments of the present application is shown in the figure;

[0049] Figure 4 The assembly schematic diagram of the electrode assembly and the support provided by some embodiments of the present application is shown in the figure;

[0050] Figure 5Assembly view of the electrode assembly and the support provided for some embodiments of the present application;

[0051] Figure 6 Assembly view of the first tab and the support provided for some embodiments of the present application;

[0052] Figure 7 Assembly view of the electrode assembly and the support provided for some embodiments of the present application;

[0053] Figure 8 Assembly view of the electrode assembly and the support provided for some embodiments of the present application;

[0054] Figure 9 Flowchart of the manufacturing method of the battery cell provided for some embodiments of the present application.

[0055] Figure: 100 - battery device; 10 - box body; 11 - first sub-box body; 12 - second sub-box body; 20 - battery cell; 21 - shell; 211 - casing; 212 - end cover; 22 - electrode assembly; 22a - flat area; 22b - bending area; 221 - first tab; 221a - first flat section; 221b - first corner section; 221c - second flat section; 221d - second corner section; 221e - first main body part; 221f - first tab; 222 - separator; 223 - second tab; 223a - third flat section; 223b - third corner section; 223c - fourth flat section; 23 - electrode terminal; 24 - support; 24a - first end; 24b - second end; 240 - sub-support; 241 - first sub-support; 242 - second sub-support; 200 - controller; 300 - motor; 1000 - vehicle; X - first direction; Y - winding axis direction of the electrode assembly; Z - thickness direction of the electrode assembly. DETAILED DESCRIPTION

[0056] The embodiments of the present application will be further described in conjunction with the drawings and examples. The detailed description and drawings of the following examples are intended to illustrate the principles of the present application, but not to limit the scope of the present application, i.e., the present application is not limited to the described examples.

[0057] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used in the description of the application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application; the description and claims of the application as well as the above abstract are intended to cover not only the embodiments described herein, but also any and all equivalents thereof.

[0058] The terms "first", "second", and the like in the description and in the claims of the present application or above-described drawings are used to distinguish different objects, and are not used to describe a particular sequential or chronological order or a primary or secondary relationship between objects.

[0059] Reference in the specification to "an embodiment", "another embodiment", etc., means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are they necessarily mutually exclusive of one another.

[0060] In the description of the present application, it is necessary to explain that, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting", "attaching" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be directly connected, or indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0061] The term "and / or" in the present application is only a description of the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B can mean that A exists alone, A and B exist together, and B exists alone. In addition, the character " / " in the present application generally represents that the front and rear associated objects have an "or" relationship.

[0062] "Multiple" appearing in the present application refers to two or more (including two), and similarly, "multiple groups" refers to two or more groups (including two groups), and "multiple pieces" refers to two or more pieces (including two pieces).

[0063] The battery device mentioned in the embodiments of the present application can include one or more battery cell assemblies for providing voltage and capacity. The battery cell assembly can include a plurality of battery cells connected in series, parallel, or mixed connection through a busbar component.

[0064] In some embodiments, the battery cell assembly is usually formed by arranging a plurality of battery cells; as an example, the battery cell assembly can be a battery module, which is formed by arranging and fixing a plurality of battery cells into an independent module. As an example, the battery module can be formed by bundling a plurality of battery cells with a cable tie.

[0065] In some embodiments, the battery device can be a battery pack, which includes a box body and one or more battery cell assemblies, and the battery cell assemblies are accommodated in the box body.

[0066] As an example, the battery cell assembly can be a battery module, and the battery cell assembly can be accommodated in the box by fixing the battery module in the box.

[0067] As an example, the battery cell assembly can also be accommodated in the box by fixing a plurality of battery cells directly in the box.

[0068] As an example, the box can include a first sub-box and a second sub-box. The first sub-box and the second sub-box are fastened so that an enclosed space is formed inside the box to accommodate the battery cell assembly. Here, enclosed means covered or closed, which can be sealed or unsealed. The first sub-box can be a top cover or a bottom plate.

[0069] As an example, the box can include a top cover, a frame, and a bottom plate. The top cover and the bottom plate are connected to the frame, respectively, so that an enclosed space is formed inside the box to accommodate the battery cell assembly.

[0070] As an example, the box can be part of a chassis structure of a vehicle. For example, the top cover of the box can be at least part of the floor of the vehicle, or the frame of the box can be at least part of the cross beam and the longitudinal beam of the vehicle.

[0071] In some embodiments, the battery device refers to an energy storage device, and the energy storage device includes a box, at least one side of which is provided with a door. The energy storage device includes an energy storage container, an energy storage cabinet, etc.

[0072] In the embodiments of the present application, the battery cell can be a secondary battery, which refers to a battery cell that can be activated by charging after discharging.

[0073] The battery cell can be, but is not limited to, a lithium ion battery, a sodium ion battery, a sodium lithium ion battery, a lithium metal battery, a sodium metal battery, a lithium sulfur battery, a magnesium ion battery, a nickel-hydrogen battery, a nickel-cadmium battery, a lead-acid battery, etc.

[0074] The battery cell generally includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator. During the charging and discharging process of the battery cell, active ions (such as lithium ions) are embedded and extracted between the positive electrode and the negative electrode. The separator is arranged between the positive electrode and the negative electrode, which can prevent the positive electrode and the negative electrode from short-circuiting, and at the same time, the active ions can pass through.

[0075] In some embodiments, the positive electrode can be a positive electrode sheet, which can include a positive electrode current collector and a positive electrode active material arranged on at least one surface of the positive electrode current collector.

[0076] As an example, the positive electrode current collector has two opposite surfaces in the thickness direction of itself, and the positive electrode active material is arranged on any one or both of the two opposite surfaces of the positive electrode current collector.

[0077] As an example, the positive current collector can employ a metal foil or a composite current collector. For example, as a metal foil, stainless steel, copper, aluminum, nickel, a carbon electrode, carbon, nickel, or titanium, etc. that is surface silver-plated can be employed. The composite current collector can include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer material base material (such as a base material of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0078] As an example, the positive active material can include at least one of lithium-containing phosphates, lithium transition metal oxides, and modified compounds of each thereof. However, the present application is not limited to these materials, and other conventional materials that can be used as a battery positive active material can also be used.

[0079] In some embodiments, the negative electrode can be a negative electrode sheet, and the negative electrode sheet can include a negative current collector.

[0080] As an example, the negative current collector can employ a metal foil or a composite current collector. For example, as a metal foil, aluminum that is surface silver-plated, stainless steel that is surface silver-plated, stainless steel, copper, aluminum, nickel, a carbon electrode, carbon, nickel, or titanium, etc. can be employed.

[0081] In some embodiments, the negative current collector has two surfaces opposite in the thickness direction thereof, and the negative active material is disposed on either one or both of the two opposite surfaces of the negative current collector.

[0082] As an example, the negative active material can employ a negative active material for a battery that is well known in the art. As an example, the negative active material can include at least one of artificial graphite, natural graphite, soft carbon, hard carbon, a silicon-based material, a tin-based material, and lithium titanate, etc. The silicon-based material can be selected from at least one of elemental silicon, a silicon oxide compound, a silicon-carbon composite, a silicon-nitrogen composite, and a silicon alloy. The tin-based material can be selected from at least one of elemental tin, a tin oxide compound, and a tin alloy. However, the present application is not limited to these materials, and other conventional materials that can be used as a battery negative active material can also be used. These negative active materials can be used alone only one or in combination of two or more.

[0083] In some embodiments, the separator is a separator film. The present application does not have a particular limitation on the type of the separator film, and any well-known porous structure separator film having good chemical stability and mechanical stability can be used.

[0084] As an example, the main material of the separator film can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator film can be a single layer film or a multi-layer composite film, and is not particularly limited. When the separator film is a multi-layer composite film, the materials of the respective layers can be the same or different, and are not particularly limited. The separator can be a separate component located between the positive and negative electrodes, or can be attached to the surfaces of the positive and negative electrodes.

[0085] In some embodiments, the separator is a solid-state electrolyte. The solid-state electrolyte is disposed between the positive and negative electrodes, and functions to transport ions and separate the positive and negative electrodes.

[0086] In some embodiments, the electrode assembly is a jelly-roll structure. The positive electrode sheet and the negative electrode sheet are wound to form the jelly-roll structure.

[0087] In some embodiments, the electrode assembly is a stacked structure.

[0088] In some embodiments, the battery cell can include a housing. The housing is used to encapsulate components such as the electrode assembly and the electrolyte. The housing can be a steel case, an aluminum case, a plastic case (e.g., polypropylene), a composite metal case (e.g., a copper-aluminum composite case), or an aluminum-plastic film, etc.

[0089] In some embodiments, the housing includes an end cap and a case body, and the case body is provided with an opening, and the end cap closes the opening to form a sealed space for accommodating the electrode assembly and the electrolyte, etc. The case body can be provided with one or more openings. The end cap can also be provided with one or more openings.

[0090] In some embodiments, at least one electrode terminal is provided on the housing, and the electrode terminal is electrically connected to the tab of the electrode assembly. The electrode terminal can be directly connected to the tab, or can be indirectly connected to the tab through an adapter. The electrode terminal can be provided on the end cap or on the case body.

[0091] In some embodiments, an explosion-proof valve is provided on the housing. The explosion-proof valve is used to release the internal pressure of the battery cell.

[0092] In some embodiments, the housing can be a sealed structure or a non-sealed structure. As an example, when the housing is a sealed structure, the housing can function to protect the electrode assembly and prevent leakage of the electrolyte, etc. When the housing is a non-sealed structure, the housing can function to protect the electrode assembly, and a sealing bag can be further included between the housing and the electrode assembly, and the sealing bag is used to encapsulate the electrode assembly and the electrolyte, etc. Specifically, the sealing bag can be a bag-shaped insulating member or an aluminum-plastic film.

[0093] As an example, the battery cell can be a prismatic battery cell, a pouch battery cell, or a battery cell of other shapes, including a square battery cell, a blade battery cell, a multi-prismatic battery cell, such as a hexagonal battery cell, etc.

[0094] The development of battery device technology needs to consider various design factors, such as performance parameters such as energy density, discharge capacity, charge-discharge rate, and the reliability of the battery device.

[0095] In some embodiments, the battery cell includes a shell and an electrode assembly, the electrode assembly is disposed in the shell, and the electrode assembly is in a jelly-roll structure. After the positive electrode sheet, the separator, and the negative electrode sheet are wound to form the electrode assembly, in order to make the battery cell smaller and have a higher energy density, the electrode assembly needs to be pre-pressed and shaped to be flat. When the electrode assembly is pre-pressed and shaped, the electrode assembly is usually placed on a bearing table, and the electrode assembly is extruded by a pressing head cooperating with the bearing table to press the electrode assembly to be flat. The flat electrode assembly means that the electrode assembly has a flat area and two bending areas connected to the two ends of the flat area. In the flat area, the surface of each layer of the positive electrode sheet, the separator, and the negative electrode sheet is a plane; in the bending area, the surface of each layer of the positive electrode sheet, the separator, and the negative electrode sheet is a curved surface.

[0096] In the pre-pressing and shaping process, the electrode assembly is prone to opening after pre-pressing (for example, the distance between the two flat sections of the innermost positive electrode sheet of the electrode assembly is greater than 5 mm, which is defined as the opening of the electrode assembly), which makes the electrode assembly prone to wrinkling in subsequent processes, thereby affecting the reliability of the battery cell. Although increasing the pre-pressing pressure can reduce the probability of opening, increasing the pre-pressing pressure can easily cause the corner section of the innermost positive electrode sheet to crack, and the cracked positive electrode sheet can easily pierce the separator and cause positive and negative short circuits, thereby reducing the reliability of the battery cell.

[0097] In view of this, in order to solve the problem of low reliability of the battery cell caused by the risk of cracking of the corner section of the innermost positive electrode sheet of the electrode assembly due to high pre-pressing pressure, the present application provides a battery cell, which includes a shell, an electrode assembly, and a support; the electrode assembly is disposed in the shell, the electrode assembly is in a jelly-roll structure, the electrode assembly includes a first electrode sheet, the innermost first electrode sheet includes a first flat section, a first corner section, and a second flat section, one end of the first flat section is the winding start end of the first electrode sheet, the first corner section connects the first flat section and the second flat section; and the support is disposed between the first flat section and the second flat section in the thickness direction of the electrode assembly. In the manufacturing process of the battery cell, the electrode assembly can be pre-pressed with a larger pre-pressing pressure, and the corner section of the electrode sheet is not prone to cracking, and the battery cell has high reliability.

[0098] In the battery cell, the support is arranged between the first flat section and the second flat section of the innermost circle of the first tab, and when the electrode assembly is pre-pressed, the stress on the first corner section can be dispersed by the support, and the risk of stress concentration of the first corner section is reduced; therefore, when the electrode assembly is pre-pressed and shaped, the risk of opening of the electrode assembly can be reduced by increasing the pre-pressing pressure, and the first corner section is not easy to crack, so that the battery cell has high reliability, thereby improving the reliability of the battery device composed of the battery cell.

[0099] The battery cell and the battery device disclosed in the embodiments of the present application can be used in an electric device such as a vehicle, a ship or an aircraft, but are not limited thereto. The power supply system of the electric device can be composed of the battery cell and the battery device disclosed in the present application.

[0100] The technical solutions described in the embodiments of the present application are applicable to various electric devices using battery cells and battery devices, for example, mobile phones, portable devices, notebook computers, electric vehicles, electric toys, electric tools, vehicles, ships and spacecraft, for example, spacecraft including airplanes, rockets, space shuttles and spacecraft, etc.

[0101] The following embodiments are described for convenience of illustration, taking a vehicle as an example of an electric device of an embodiment of the present application.

[0102] Please refer to Figure 1 , Figure 1 The vehicle 1000 can be a fuel automobile, a gas automobile or a new energy automobile, and the new energy automobile can be a pure electric automobile, a hybrid electric automobile or a range extended automobile, etc. The vehicle 1000 is internally provided with a battery device 100, which can be arranged at the bottom, the head or the tail of the vehicle 1000. The battery device 100 can be used for power supply of the vehicle 1000, for example, the battery device 100 can be used as an operating power source of the vehicle 1000, for example, for the working power demand of the circuit system of the vehicle 1000, for example, for the starting, navigation and running of the vehicle 1000.

[0103] The vehicle 1000 can further include a controller 200 and a motor 300, and the controller 200 is used to control the battery device 100 to supply power to the motor 300, for example, for the working power demand of the vehicle 1000 during starting, navigation and running.

[0104] In some embodiments of the present application, the battery device 100 can not only be used as an operating power source of the vehicle 1000, but also be used as a driving power source of the vehicle 1000, instead of or partially instead of fuel or natural gas to provide driving power for the vehicle 1000.

[0105] Please refer to Figure 2 , Figure 2 The structural exploded view of the battery device provided for some embodiments of the present application is shown. The battery device 100 includes a box 10 and a battery cell 20, and the battery cell 20 is accommodated in the box 10.

[0106] The box 10 is used to provide an accommodation space for the battery cell 20, and the box 10 can adopt various structures. In some embodiments, the box 10 can include a first sub-box 11 and a second sub-box 12, and the first sub-box 11 and the second sub-box 12 are mutually covered, and the first sub-box 11 and the second sub-box 12 jointly define an accommodation space for accommodating the battery cell 20. The second sub-box 12 can be a hollow structure with one end open, and the first sub-box 11 can be a plate-shaped structure, and the first sub-box 11 is covered on the open side of the second sub-box 12, so that the first sub-box 11 and the second sub-box 12 jointly define the accommodation space; the first sub-box 11 and the second sub-box 12 can also be hollow structures with one side open, and the open side of the first sub-box 11 is covered on the open side of the second sub-box 12.

[0107] In the battery device 100, the battery cell 20 can be multiple, and the multiple battery cells 20 can be connected in series, in parallel, or in a mixed manner. The mixed manner means that the multiple battery cells 20 are connected in series and in parallel. The multiple battery cells 20 can be directly connected in series, in parallel, or in a mixed manner, and then the whole of the multiple battery cells 20 is accommodated in the box 10; of course, the battery device 100 can also be that the multiple battery cells 20 are first connected in series, in parallel, or in a mixed manner to form a battery module, and then the multiple battery modules are connected in series, in parallel, or in a mixed manner to form a whole, and the whole is accommodated in the box 10.

[0108] The battery device 100 can also include other structures, for example, the battery device 100 can also include a current collecting component for realizing the electrical connection between the multiple battery cells 20.

[0109] Please refer to Figure 3 , Figure 3 The structural exploded view of the battery cell provided for some embodiments of the present application is shown. As shown in Figure 3 , the battery cell 20 includes a shell 21, an electrode assembly 22, and other functional components. The shell 21 includes a shell body 211 and an end cover 212, the shell body 211 has an opening, and the end cover 212 closes the opening to isolate the internal environment of the battery cell 20 from the external environment.

[0110] The shell 211 is a component for fitting with the end cover 212 to form an internal environment of the battery cell 20, wherein the formed internal environment can be used to accommodate the electrode assembly 22, electrolyte and other components. The shell 211 and the end cover 212 can be independent components. The shell 211 can be in various shapes and sizes. Specifically, the shape of the shell 211 can be determined according to the specific shape and size of the electrode assembly 22. The material of the shell 211 can be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc.

[0111] The end cover 212 refers to a component that covers the opening of the shell 211 to isolate the internal environment of the battery cell 20 from the external environment. Without limitation, the shape of the end cover 212 can be adapted to the shape of the shell 211 to fit the shell 211. Optionally, the end cover 212 can be made of a material with certain hardness and strength (such as aluminum alloy), so that the end cover 212 is not easily deformed when subjected to extrusion collision, so that the battery cell 20 can have higher structural strength, and the reliability can also be improved. The end cover 212 can be provided with functional components such as the electrode terminal 23. The electrode terminal 23 can be used to electrically connect with the electrode assembly 22 for outputting or inputting the electrical energy of the battery cell 20. The material of the end cover 212 can also be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., which are not specially limited in the embodiments of the present application. In some embodiments, an insulating structure can also be provided on the inner side of the end cover 212, which can be used to isolate the electrical connection components in the shell 211 from the end cover 212 to reduce the risk of short circuit. Exemplarily, the insulating structure can be plastic, rubber, etc.

[0112] The electrode assembly 22 is a component in which electrochemical reactions occur in the battery cell 20. One or more electrode assemblies 22 can be contained in the shell 211. The electrode assembly 22 is mainly formed by winding or stacking the positive electrode sheet and the negative electrode sheet, and generally has a separator film between the positive electrode sheet and the negative electrode sheet, which is used to separate the positive electrode sheet and the negative electrode sheet to avoid internal short circuit of the positive electrode sheet and the negative electrode sheet. The positive electrode sheet and the negative electrode sheet have a part of active material constituting the main body of the electrode assembly 22, and the parts of the positive electrode sheet and the negative electrode sheet without active material each constitute a tab. The positive electrode tab and the negative electrode tab can be located at one end of the main body or at two ends of the main body respectively.

[0113] Please refer to Figure 3 , and further refer to Figure 4 , Figure 4An assembly diagram of an electrode assembly and a support member is provided for some embodiments of the present application. An embodiment of the present application provides a battery monomer 20, which comprises a shell 21, an electrode assembly 22 and a support member 24; the electrode assembly 22 is arranged in the shell 21, the electrode assembly 22 is in a wound structure, and the electrode assembly 22 comprises a first electrode sheet 221; the first electrode sheet 221 in the innermost circle comprises a first flat section 221a, a first corner section 221b and a second flat section 221c; one end of the first flat section 221a is the winding start end of the first electrode sheet 221, and the first corner section 221b connects the first flat section 221a and the second flat section 221c; along the thickness direction Z of the electrode assembly, the support member 24 is arranged between the first flat section 221a and the second flat section 221c.

[0114] In some embodiments, referring to Figure 3 , the shell 21 can be a cuboid.

[0115] In some embodiments, referring to Figure 3 , the battery monomer 20 can be a hard-shell square battery monomer.

[0116] The electrode assembly 22 is in a wound structure, and the electrode assembly 22 comprises a first electrode sheet 221, a separator 222 and a second electrode sheet 223; the second electrode sheet 223 is opposite in polarity to the first electrode sheet 221; the separator 222 is arranged between the first electrode sheet 221 and the second electrode sheet 223; and the first electrode sheet 221, the separator 222 and the second electrode sheet 223 are wound to form the electrode assembly 22. The first electrode sheet 221 can be a negative electrode sheet, and the second electrode sheet 223 can be a positive electrode sheet; or, the first electrode sheet 221 can be a positive electrode sheet, and the second electrode sheet 223 can be a negative electrode sheet.

[0117] The electrode assembly 22 is in a flat shape, and the electrode assembly 22 has a flat area 22a and a bending area 22b located at both ends of the flat area 22a; the flat area 22a refers to an area in the electrode assembly 22 having a parallel structure, i.e., the surface of each layer of negative electrode sheet, positive electrode sheet and separator 222 in the flat area 22a is a plane; the bending area 22b refers to an area in the electrode assembly 22 having a bending structure, i.e., the negative electrode sheet, positive electrode sheet and separator 222 in the bending area 22b are all bent, and the surface of each layer of negative electrode sheet, positive electrode sheet and separator 222 in the bending area 22b of the electrode assembly 22 is a curved surface.

[0118] The first flat section 221a and the second flat section 221c are parts of the first electrode sheet 221 in the innermost circle, which are in the flat area 22a. The first corner section 221b is a part of the first electrode sheet 221 in the innermost circle, which is in the bending area 22b. The first flat section 221a and the second flat section 221c are arranged in parallel.

[0119] When the electrode assembly 22 is wound and formed, one end of the first flat section 221a is first wound around the winding needle, so that the one end of the first flat section 221a is the winding start end of the first tab 221. In the winding direction of the electrode assembly 22, the first corner section 221b is the corner section closest to the winding start end of the first tab 221.

[0120] The thickness direction Z of the electrode assembly can be the thickness direction of the battery cell 20, and the first flat section 221a and the second flat section 221c are arranged along the thickness direction Z of the electrode assembly.

[0121] The support 24 is a component for supporting the first flat section 221a and the second flat section 221c. When the first flat section 221a and the second flat section 221c are close to each other, the first support 24 can support the first flat section 221a and the second flat section 221c to absorb the pressure received when the first flat section 221a and the second flat section 221c are folded.

[0122] In some embodiments, the support 24 has a first surface, a second surface, and a third surface. The first surface is arranged to face the first flat section 221a, the second surface is arranged to face the second flat section 221c, and the third surface is connected to the first surface and the second surface and arranged to face the first corner section 221b. The first surface and the second surface are oppositely arranged along the thickness direction of the support, which is parallel to the thickness direction Z of the electrode assembly. The third surface is a circular arc surface, and the first surface and the second surface are circularly arc transitioned at the connection corresponding to the first corner section 221b. This can reduce the risk of the support 24 damaging the first corner section 221b, and facilitate improving the reliability of the battery cell 20.

[0123] After the winding of the electrode assembly 22 is completed, the support 24 is inserted into the circle formed by the first tab 221 of the innermost circle, and the support 24 is located between the first flat section 221a and the second flat section 221c. When the electrode assembly 22 is pre-pressed, the gap between the first flat section 221a and the second flat section 221c gradually decreases until the support 24 supports the first flat section 221a and the second flat section 221c. At this time, the support 24 can be in direct contact with the first flat section 221a, and the support 24 and the second flat section 221c can have a separation film 222 therebetween; or the support 24 can be in direct contact with the second flat section 221c, and the support 24 and the first flat section 221a can have a separation film 222 therebetween; or the support 24 and the first flat section 221a therebetween, and the support 24 and the second flat section 221c therebetween can all have a separation film 222 therebetween.

[0124] According to the battery cell 20 provided by the embodiment of the present application, the support 24 is arranged between the first flat section 221a and the second flat section 221c of the innermost circle of the first tab 221, and when the electrode assembly 22 is pre-pressed, the support 24 can share the pressure received by the first flat section 221a and the second flat section 221c when they are folded, disperse the stress received by the first corner section 221b, and reduce the risk of stress concentration of the first corner section 221b. Therefore, when the electrode assembly 22 is pre-pressed and shaped, the risk of opening of the electrode assembly 22 can be reduced by increasing the pre-pressing pressure, and the first corner section 221b is less likely to crack, so that the battery cell 20 has higher reliability, thereby improving the reliability of the battery device 100 constituted by the battery cell 20.

[0125] According to some embodiments of the present application, the support 24 is in the form of a sheet, and the thickness direction of the support 24 is parallel to the thickness direction Z of the electrode assembly.

[0126] The support 24 is in the form of a sheet, and the support 24 can also be referred to as a gasket.

[0127] In the above scheme, the support 24 is in the form of a sheet, and the support 24 can occupy a smaller space while meeting the support requirement.

[0128] Please refer to Figure 4 According to some embodiments of the present application, the thickness H of the support 24 satisfies 1mm≤H≤5mm.

[0129] For example, the thickness H of the support 24 can be, but is not limited to, any one of 1mm, 1.2mm, 1.4mm, 1.6mm, 1.8mm, 2mm, 2.2mm, 2.4mm, 2.6mm, 2.8mm, 3mm, 3.2mm, 3.4mm, 3.6mm, 3.8mm, 4mm, 4.2mm, 4.4mm, 4.6mm, 4.8mm or 5mm, or a range between any two of them.

[0130] The thickness of the support 24 can be measured by a micrometer or a vernier caliper.

[0131] In the above scheme, the thickness H of the support 24 satisfies the above relationship (1mm≤H≤5mm), for example, when H≥1mm, the thickness of the support 24 is relatively thick, the support 24 has higher support strength, which is convenient for reducing the stress concentration of the first corner section 221b, and for example, when H≤5mm, the support 24 occupies a smaller space in the thickness direction Z of the electrode assembly, and has less influence on the opening of the electrode assembly 22.

[0132] According to some embodiments of the present application, 1mm≤H≤3mm.

[0133] For example, the thickness H of the support 24 can be, but is not limited to, any one of or a range between any two of 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, 2 mm, 2.1 mm, 2.2 mm, 2.3 mm, 2.4 mm, 2.5 mm, 2.6 mm, 2.7 mm, 2.8 mm, 2.9 mm, or 3 mm.

[0134] In the above scheme, the thickness H of the support 24 satisfies the above relationship (1 mm≤H≤3 mm), and in the case of satisfying the support strength, the spatial occupation of the support 24 is further reduced, and the influence on the opening of the electrode assembly 22 is reduced.

[0135] Please refer to Figure 4 According to some embodiments of the present application, the first pole piece 221 of the innermost circle further comprises a second corner segment 221d connected to one end of the second straight segment 221c away from the first corner segment 221b; in the first direction X, the support 24 has a first end 24a close to the first corner segment 221b and a second end 24b away from the first corner segment 221b, and the first direction X, the thickness direction Z of the electrode assembly, and the winding axis direction Y of the electrode assembly are perpendicular to each other; in the first direction X, the distance between the first end 24a and the outer side vertex of the first corner segment 221b is L1, and the distance between the second end 24b and the outer side vertex of the second corner segment 221d is L2, satisfying 0 < L1≤15 mm and 0 < L2≤15 mm.

[0136] In the winding direction of the electrode assembly 22, the first straight segment 221a, the first corner segment 221b, the second straight segment 221c, and the second corner segment 221d are sequentially distributed, the second straight segment 221c connects the first corner segment 221b and the second corner segment 221d, and the first corner segment 221b and the second corner segment 221d are two corner segments of the first pole piece 221 of the innermost circle.

[0137] In some embodiments, the first corner segment 221b and the second corner segment 221d are arranged apart in the first direction X, and the two ends of the second straight segment 221c in the first direction X are connected to the first corner segment 221b and the second corner segment 221d, respectively.

[0138] In some embodiments, the support 24 can extend in the first direction X, and the length direction of the support 24 can be parallel to the first direction X. Alternatively, the support 24 can extend in the winding axis direction Y of the electrode assembly, and the width direction of the support 24 can be parallel to the first direction X.

[0139] In some embodiments, the support 24 is located between the first corner segment 221b and the second corner segment 221d in the first direction X, i.e. the support 24 is located in the area enclosed by the first pole piece 221 of the innermost turn. The first end 24a and the second end 24b are opposite ends of the support 24 in the first direction X, the first end 24a is closer to the first corner segment 221b than the second end 24b, and the second end 24b is closer to the second corner segment 221d than the first end 24a.

[0140] In some embodiments, the first end 24a can at least partially overlap the first corner segment 221b in the projection direction of the thickness direction Z of the electrode assembly, and / or the second end 24b can at least partially overlap the second corner segment 221d in the projection direction of the thickness direction Z of the electrode assembly.

[0141] In some embodiments, the first end 24a can not overlap the first corner segment 221b in the projection direction of the thickness direction Z of the electrode assembly, but the gap between the projection of the first end 24a and the projection of the first corner segment 221b in the projection plane perpendicular to the thickness direction Z of the electrode assembly is small, for example, the gap is less than 2 mm, so that the support 24 can absorb the pressure received when the first flat segment 221a and the second flat segment 221c are folded, and facilitate the dispersion of stress on the first corner segment 221b. Similarly, the second end 24b can not overlap the second corner segment 221d in the projection direction of the thickness direction Z of the electrode assembly, but the gap between the projection of the second end 24b and the projection of the second corner segment 221d in the projection plane perpendicular to the thickness direction Z of the electrode assembly is small, for example, the gap is less than 2 mm, so that the support 24 can absorb the pressure received when the first flat segment 221a and the second flat segment 221c are folded, and facilitate the dispersion of stress on the second corner segment 221d.

[0142] In some embodiments, the number of supports 24 can be one, and the support 24 has a large overlapping area with the second flat segment 221c in the thickness direction Z of the electrode assembly.

[0143] The first corner segment 221b is approximately arc-shaped, and the outer side vertex of the first corner segment 221b can be the vertex of the first corner segment 221b away from the winding axis of the electrode assembly 22.

[0144] The distance L1 between the first end 24a and the outer vertex of the first corner segment 221b can be obtained by scanning the battery cell 20 along the thickness direction Z of the electrode assembly using a CT scanning device, for example. In the obtained image, the distance L1 between the first end 24a and the outer vertex of the first corner segment 221b is measured. The distance L2 between the second end 24b and the outer vertex of the second corner segment 221d can be measured according to the method for measuring the distance L1.

[0145] In some embodiments, the distance L1 between the first end 24a and the outer vertex of the first corner segment 221b can be, but is not limited to, any one of or a range between any two of 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, 5 mm, 5.5 mm, 6 mm, 6.5 mm, 7 mm, 7.5 mm, 8 mm, 8.5 mm, 9 mm, 9.5 mm, 10 mm, 10.5 mm, 11 mm, 11.5 mm, 12 mm, 12.5 mm, 13 mm, 13.5 mm, 14 mm, 14.5 mm, or 15 mm.

[0146] In some embodiments, the distance L2 between the second end 24b and the outer vertex of the second corner segment 221d can be, but is not limited to, any one of or a range between any two of 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, 5 mm, 5.5 mm, 6 mm, 6.5 mm, 7 mm, 7.5 mm, 8 mm, 8.5 mm, 9 mm, 9.5 mm, 10 mm, 10.5 mm, 11 mm, 11.5 mm, 12 mm, 12.5 mm, 13 mm, 13.5 mm, 14 mm, 14.5 mm, or 15 mm.

[0147] In some embodiments, L1 and L2 can be equal.

[0148] In the above scheme, the distance L1 between the first end 24a and the outer vertex of the first corner segment 221b, the distance L2 between the second end 24b and the outer vertex of the second corner segment 221d satisfy the above relationship (0 < L1 ≤ 15 mm, 0 < L2 ≤ 15 mm), the first end 24a corresponds to the first corner segment 221b, and the second end 24b corresponds to the second corner segment 221d. When the electrode assembly 22 is pre-pressed, the support 24 can absorb the pressure when the first flat segment 221a and the second flat segment 221c are folded, can disperse the stress on the first corner segment 221b and the second corner segment 221d, can reduce the stress concentration of the first corner segment 221b and the second corner segment 221d, and can reduce the risk of cracking of the first corner segment 221b and the second corner segment 221d.

[0149] According to some embodiments of the present application, 2mm≤L1≤10mm, 2mm≤L2≤10mm.

[0150] In some embodiments, the distance L1 between the first end 24a and the outer side vertex of the first corner segment 221b can be, but is not limited to, any one of 2mm, 2.4mm, 2.8mm, 3mm, 3.4mm, 3.8mm, 4mm, 4.4mm, 4.8mm, 5mm, 5.4mm, 5.8mm, 6mm, 6.4mm, 6.8mm, 7mm, 7.4mm, 7.8mm, 8mm, 8.4mm, 8.8mm, 9mm, 9.4mm, 9.8mm or 10mm, or a range between any two of them.

[0151] In some embodiments, the distance L2 between the second end 24b and the outer side vertex of the second corner segment 221d can be, but is not limited to, any one of 2mm, 2.4mm, 2.8mm, 3mm, 3.4mm, 3.8mm, 4mm, 4.4mm, 4.8mm, 5mm, 5.4mm, 5.8mm, 6mm, 6.4mm, 6.8mm, 7mm, 7.4mm, 7.8mm, 8mm, 8.4mm, 8.8mm, 9mm, 9.4mm, 9.8mm or 10mm, or a range between any two of them.

[0152] In the above scheme, the distance L1 between the first end 24a and the outer side vertex of the first corner segment 221b, and the distance L2 between the second end 24b and the outer side vertex of the second corner segment 221d satisfy the above relationship (2mm≤L1≤10mm, 2mm≤L2≤10mm), the first end 24a is arranged close to the first corner segment 221b, and the second end 24b is arranged close to the second corner segment 221d, further sharing the stress of the first corner segment 221b and the second corner segment 221d, reducing the risk of cracking of the first corner segment 221b and the second corner segment 221d.

[0153] Please refer to Figure 4 According to some embodiments of the present application, the first pole piece 221 of the innermost ring further comprises a second corner segment 221d connected to one end of the second straight segment 221c away from the first corner segment 221b; in the first direction X, the size of the support 24 is W1, the distance between the outer side vertex of the first corner segment 221b and the outer side vertex of the second corner segment 221d is W2, satisfying 0.5≤W1 / W2<1, and the first direction X, the thickness direction Z of the electrode assembly and the winding axis direction Y of the electrode assembly are perpendicular to each other.

[0154] The distance W2 between the outer vertex of the first corner segment 221b and the outer vertex of the second corner segment 221d can be the maximum dimension of the first pole piece 221 of the innermost ring in the first direction X.

[0155] In some embodiments, the ratio W1 / W2 of the dimension W1 of the support 24 in the first direction X and the distance W2 between the outer vertex of the first corner segment 221b and the outer vertex of the second corner segment 221d can be, but is not limited to, any one of 0.5, 0.6, 0.7, 0.8, 0.9 or 1 or a range between any two of them.

[0156] The greater the ratio W1 / W2 of the dimension W1 of the support 24 in the first direction X and the distance W2 between the outer vertex of the first corner segment 221b and the outer vertex of the second corner segment 221d, the greater the corresponding area of the support 24 to the second flat segment 221c in the first direction X, and the better the supporting effect of the support 24 to the first flat segment 221a and the second flat segment 221c.

[0157] In some embodiments, the first end 24a of the support 24 is arranged close to the first corner segment 221b, and the second end 24b is arranged close to the second corner segment 221d, so that the dimension W1 of the support 24 in the first direction X can be greater, that is, W1 / W2 is greater.

[0158] In the above scheme, the dimension W1 of the support 24 in the first direction X and the distance W2 between the outer vertex of the first corner segment 221b and the outer vertex of the second corner segment 221d satisfy the above relationship (0.5≤W1 / W2<1), the support 24 has a large overlapping area with the second flat segment 221c, and when the counter electrode assembly 22 is pre-pressed, the support 24 can absorb more pressure, which is conducive to dispersing the stress on the first corner segment 221b and reducing the risk of cracking of the first corner segment 221b.

[0159] According to some embodiments of the present application, 0.9≤W1 / W2<1.

[0160] In some embodiments, the ratio W1 / W2 of the dimension W1 of the support 24 in the first direction X and the distance W2 between the outer vertex of the first corner segment 221b and the outer vertex of the second corner segment 221d can be, but is not limited to, any one of 0.9, 0.92, 0.94, 0.96, 0.98 or 1 or a range between any two of them.

[0161] In the above scheme, the size W1 of the support 24 in the first direction X and the distance W2 between the outer vertex of the first corner section 221b and the outer vertex of the second corner section 221d satisfy the above relationship (0.9≤W1 / W2<1), and the size of the support 24 in the first direction X can be designed to be larger, which can correspond to the two corner sections (the first corner section 221b and the second corner section 221d) of the first pole piece 221 of the innermost row in the first direction X, facilitate the dispersion of the stress of the two corner sections of the first pole piece 221 of the innermost row, and be beneficial to reducing the risk of cracking of the two corner sections of the first pole piece 221 of the innermost row.

[0162] Please refer to Figure 5 , Figure 5 The assembly schematic diagram of the electrode assembly and the support provided by some embodiments of the present application is shown. According to some embodiments of the present application, the support 24 includes two sub-supports 240, and the two sub-supports 240 are arranged in the first direction X, and the first direction X, the thickness direction Z of the electrode assembly, and the winding axis direction Y of the electrode assembly are perpendicular to each other.

[0163] The two sub-supports 240 are two components of the support 24, and the two sub-supports 240 are arranged in the first direction X. The two sub-supports 240 can include a first sub-support 241 and a second sub-support 242. In the first direction X, the first sub-support 241 can be closer to the first corner section 221b relative to the second sub-support 242, and the second sub-support 242 can be closer to the second corner section 221d relative to the first sub-support 241.

[0164] In the first direction X, one end of the first sub-support 241 close to the first corner section 221b is a first end 24a, and one end of the second sub-support 242 close to the second corner section 221d is a second end 24b.

[0165] In some embodiments, in the first direction X, the distance between the first sub-support 241 and the outer vertex of the first corner section 221b can be L1, and the distance between the second sub-support 242 and the outer vertex of the second corner section 221d can be L2.

[0166] In the above scheme, the two sub-supports 240 are arranged in the first direction X, which can absorb the pressure received by the first flat section 221a and the second flat section 221c when they are folded in the two positions in the first direction X, facilitate the dispersion of the stress received by the corner sections of the first pole piece 221 of the innermost row, and be beneficial to reducing the risk of cracking of the corner sections of the first pole piece 221 of the innermost row. At the same time, the two sub-supports 240 arranged in the first direction X can reduce the total size of the support 24 in the first direction X, reduce the material of the support 24, and reduce the cost.

[0167] Please refer to Figure 5 According to some embodiments of the present application, in the first direction X, the size of the sub-support 240 is W3, which satisfies 5mm≤W3≤50mm.

[0168] In some embodiments, the size W3 of the sub-support 240 in the first direction X can be, but is not limited to, any one of 5mm, 10mm, 15mm, 20mm, 25mm, 30mm, 35mm, 40mm, 45mm or 50mm, or a range between any two of them.

[0169] In the above scheme, the size W3 of the sub-support 240 in the first direction X satisfies the above relationship (5mm≤W3≤50mm), on the one hand, when W3≥5mm, the sub-support 240 has a larger overlapping area with the first flat section 221a and the second flat section 221c, which can facilitate absorbing the pressure received by the first flat section 221a and the second flat section 221c when they are folded, facilitating the dispersion of the stress received by the two corner sections of the innermost first pole piece 221, and being conducive to reducing the risk of cracking of the two corner sections of the innermost first pole piece 221; on the other hand, when W3≤50mm, the size of the sub-support 240 in the first direction X can be smaller, so as to facilitate reducing the material of the sub-support 240 and reducing the cost.

[0170] According to some embodiments of the present application, 10mm≤W3≤30mm.

[0171] In some embodiments, the size W3 of the sub-support 240 in the first direction X can be, but is not limited to, any one of 10mm, 12mm, 14mm, 16mm, 18mm, 20mm, 22mm, 24mm, 26mm, 28mm or 30mm, or a range between any two of them.

[0172] In the above scheme, the size W3 of the sub-support 240 in the first direction X satisfies the above relationship (10mm≤W3≤30mm), on the one hand, when W3≥10mm, the sub-support 240 has a higher strength, which can absorb the pressure received by the first flat section 221a and the second flat section 221c when they are folded, on the other hand, when W3≤30mm, the size of the sub-support 240 in the first direction X is smaller, further reducing the material of the sub-support 240 and reducing the cost.

[0173] According to some embodiments of the present application, the first pole piece 221 comprises a first main body part 221e and a first tab 221f, the first tab 221f extending from an end of the first main body part 221e in the winding axis direction Y of the electrode assembly; along the winding axis direction Y of the electrode assembly, the size of the first main body part 221e is K1, and the size of the support is K2, which satisfies 0.5≤K2 / K1≤1.

[0174] The first tab 221f can extend from one end of the first body portion 221e in the winding axis direction Y of the electrode assembly, or can extend from both ends of the first body portion 221e in the winding axis direction Y of the electrode assembly.

[0175] The dimension K1 of the first body portion 221e in the winding axis direction Y of the electrode assembly can also be regarded as the dimension of the first body portion 221e in the width direction of the first tab 221.

[0176] In some embodiments, the support 24 has a first center line perpendicular to the winding axis direction Y of the electrode assembly, the first body portion 221e has a second center line perpendicular to the winding axis direction Y of the electrode assembly, and the orthographic projection of the first center line can overlap the orthographic projection of the second center line on the same projection plane perpendicular to the thickness direction Z of the electrode assembly. In other embodiments, there can be a gap between the orthographic projection of the first center line and the orthographic projection of the second center line in the winding axis direction Y of the electrode assembly on the same projection plane perpendicular to the thickness direction Z of the electrode assembly, and the gap is not greater than 1 mm.

[0177] In some embodiments, K2 / K1 can be, but is not limited to, one of 0.5, 0.6, 0.7, 0.8, 0.9 or 1, or a range between any two of them.

[0178] In some embodiments, the support 24 does not exceed the edge of the first body portion 221e in the winding axis direction Y of the electrode assembly.

[0179] In the above scheme, K1 / K2 satisfies the above relationship, so that the support and the first body portion 221e have a larger overlapping area in the winding axis direction of the electrode assembly, so as to facilitate the support of the first flat section and the second flat section, and facilitate the absorption of the pressure received when the first flat section and the second flat section are folded.

[0180] According to some embodiments of the present application, 0.8≤K2 / K1≤1.

[0181] In the above scheme, when 0.8≤K2 / K1, the overlapping area of the support and the first body portion 221e in the winding axis direction of the electrode assembly can be further increased, so as to facilitate the support of the first flat section and the second flat section, and facilitate the absorption of the pressure received when the first flat section and the second flat section are folded.

[0182] According to some embodiments of the present application, the support 24 is an insulating sheet.

[0183] The support 24 can be an electrically insulating sheet structure, and the support 24 has good insulating properties.

[0184] In the above scheme, the support 24 is an insulating sheet, which can reduce the risk of positive and negative contact short circuit.

[0185] According to some embodiments of the present application, the density of the support 24 is 0.8g / cm 3 ~2.2g / cm 3 .

[0186] In some embodiments, the density of the support 24 can be any one of 0.8g / cm 3 , 0.9g / cm 3 , 1.2g / cm 3 , 1.4g / cm 3 , 1.6g / cm 3 , 1.8g / cm 3 , 2g / cm 3 , 2.16g / cm 3 or 2.2g / cm 3 , or a range between any two of them.

[0187] In the above scheme, the density of the support 24 satisfies the above relationship (0.8g / cm 3 ~2.2g / cm 3 ), the weight of the support 24 is lighter, which is beneficial to reduce the influence of the support 24 on the weight energy density of the battery monomer 20.

[0188] According to some embodiments of the present application, the material of the support 24 is polytetrafluoroethylene, polyvinyl chloride, polypropylene or polycarbonate.

[0189] Polytetrafluoroethylene, polyvinyl chloride, polypropylene or polycarbonate all have electrical insulation and low density.

[0190] In the above scheme, the material of the support 24 is polytetrafluoroethylene, polyvinyl chloride, polypropylene or polycarbonate, which has good insulation performance, is corrosion resistant, and has a long service life.

[0191] Please refer to Figure 4 and Figure 5 , according to some embodiments of the present application, the electrode assembly 22 includes a second sheet 223, the second sheet 223 is opposite in polarity to the first sheet 221, the innermost circle of the second sheet 223 includes a third flat section 223a, a third corner section 223b and a fourth flat section 223c, one end of the third flat section 223a is the winding start end of the second sheet 223, the third corner section 223b connects the third flat section 223a and the fourth flat section 223c; along the thickness direction Z of the electrode assembly, the first flat section 221a and the second flat section 221c are located between the third flat section 223a and the fourth flat section 223c, and the first corner section 221b is located inside the third corner section 223b.

[0192] Optionally, the first tab 221 is a negative electrode tab, and the second tab 223 is a positive electrode tab. When the electrode assembly 22 is wound, the negative electrode tab is wound on the winding needle before the positive electrode tab, so that the negative electrode tab of the innermost layer is located inside the positive electrode tab of the innermost layer.

[0193] The third flat section 223a and the fourth flat section 223c are parts of the second tab 223 of the innermost layer located in the flat area 22a. The third corner section 223b is a part of the second tab 223 of the innermost layer located in the bending area 22b.

[0194] When the electrode assembly 22 is wound and formed, one end of the third flat section 223a is first wound on the winding needle, so that the end of the third flat section 223a is the winding starting end of the second tab 223. In the winding direction of the electrode assembly 22, the third corner section 223b is the corner section of the second tab 223 closest to the winding starting end of the second tab 223.

[0195] In some embodiments, the third flat section 223a and the fourth flat section 223c are arranged along the thickness direction Z of the electrode assembly. In the thickness direction Z of the electrode assembly, the first flat section 221a is located between the third flat section 223a and the second flat section 221c, and the second flat section 221c is located between the first flat section 221a and the fourth flat section 223c.

[0196] The first corner section 221b is arranged adjacent to the third corner section 223b. The first corner section 221b and the third corner section 223b are located in the same bending area 22b of the electrode assembly 22, and the first corner section 221b is closer to the winding axis of the electrode assembly 22 than the third corner section 223b.

[0197] In the above scheme, the second tab 223 is opposite in polarity to the first tab 221, the first flat section 221a and the second flat section 221c are located between the third flat section 223a and the fourth flat section 223c, the first corner section 221b is located inside the third corner section 223b, the first tab 221 is wound first before the second tab 223 when the electrode assembly 22 is wound and formed, the first tab 221 of the innermost layer is located inside the second tab 223 of the innermost layer, the support 24 is arranged between the first flat section 221a and the second flat section 221c, so as to form a support between the first flat section 221a and the second flat section 221c, to absorb the pressure received by the first flat section 221a and the second flat section 221c when they are folded, and to facilitate the dispersion of stress received by the first corner section 221b.

[0198] Please refer to Figure 7 and Figure 8 , Figure 7An assembly diagram of the electrode assembly and the support provided for some embodiments of the present application, Figure 8 An assembly diagram of the electrode assembly and the support provided for some embodiments of the present application. According to some embodiments of the present application, the electrode assembly 22 includes a second tab 223 opposite in polarity to the first tab 221, the innermost circle of the second tab 223 includes a third flat section 223a, a third corner section 223b and a fourth flat section 223c, one end of the third flat section 223a is the winding start end of the second tab 223, the third corner section 223b connects the third flat section 223a and the fourth flat section 223c; along the thickness direction Z of the electrode assembly, the first flat section 221a is located between the third flat section 223a and the fourth flat section 223c, and the third flat section 223a is located between the first flat section 221a and the second flat section 221c. The support 24 is arranged between the first flat section 221a and the third flat section 223a.

[0199] In some embodiments, the third corner section 223b is arranged opposite to the first corner section 221b along the first direction X, the third corner section 223b is arranged adjacent to the second corner section 221d, and the third corner section 223b is located inside the second corner section 221d.

[0200] In the above scheme, the innermost circle of the first tab 221 and the innermost circle of the second tab 223 are arranged in a plug-in manner, the first flat section 221a of the innermost circle of the first tab 221 can be arranged as a double-sided active material coating area, and the third flat section 223a of the innermost circle of the second tab 223 can be arranged as a double-sided active material coating area, so that the battery monomer 20 has a higher energy density. At the same time, the support 24 is arranged between the first flat section 221a and the third flat section 223a, so as to form a support between the first flat section 221a and the third flat section 223a. The support 24 can absorb the pressure received by the first flat section 221a and the third flat section 223a when they are folded, facilitate the dispersion of the stress received by the first corner section 221b and the third corner section 223b, reduce the risk of stress concentration of the first corner section 221b and the third corner section 223b, thereby reducing the risk of cracking of the first corner section 221b and the third corner section 223b, and further improving the reliability of the battery monomer 20.

[0201] According to some embodiments of the present application, the second tab 223 can include a second main body part and a second lug, the second lug extending from an end of the second main body part in the winding axis direction Y of the electrode assembly; the second lug can be located on the same side of the second main body part as the first lug 221f, or the second lug can be located on both sides of the second main body part in the winding axis direction Y of the electrode assembly as the first lug 221f.

[0202] According to some embodiments of the present application, the embodiments of the present application further provide a battery device 100 comprising the battery cell 20 provided according to any of the above embodiments.

[0203] According to some embodiments of the present application, the embodiments of the present application further provide a battery device 100 comprising the battery cell 20 provided according to any of the above embodiments.

[0204] The battery device can be a device or system of any of the above applications.

[0205] Please refer to Figure 9 , Figure 9 A flowchart of a manufacturing method of a battery cell according to some embodiments of the present application is shown. According to some embodiments of the present application, the embodiments of the present application provide a manufacturing method of a battery cell, comprising:

[0206] S100, winding the first electrode tab 221, the isolation film 222 and the second electrode tab 223 into an electrode assembly 22;

[0207] S200, arranging a support 24 on the inner side of the first electrode tab 221 of the innermost circle;

[0208] S300, extruding the electrode assembly 22 provided with the support 24 into a flat shape, so that the support 24 is located between the two flat sections of the first electrode tab 221 of the innermost circle.

[0209] In the step "S100, winding the first electrode tab 221, the isolation film 222 and the second electrode tab 223 into an electrode assembly 22", the first electrode tab 221 can be wound on the winding needle before the second electrode tab 223, so that after the electrode assembly 22 is extruded into a flat shape, the first flat section 221a and the second flat section 221c of the first electrode tab 221 are located between the third flat section 223a and the fourth flat section 223c of the second electrode tab 223, and the first corner section 221b is located on the inner side of the third corner section 223b.

[0210] In the step "S100, winding the first electrode tab 221, the isolation film 222 and the second electrode tab 223 into an electrode assembly 22", the innermost circle of the first electrode tab 221 and the innermost circle of the second electrode tab 223 are arranged in a plug-in manner, so that after the electrode assembly 22 is extruded into a flat shape, the first flat section 221a is located between the third flat section 223a and the fourth flat section 223c, and the third flat section 223a is located between the first flat section 221a and the second flat section 221c.

[0211] In the step "S200, arranging a support 24 on the inner side of the first electrode tab 221 of the innermost circle", the inner side of the first electrode tab 221 of the innermost circle refers to the side of the first electrode tab 221 facing the winding axis of the electrode assembly.

[0212] In the step "S300, the electrode assembly 22 provided with the support 24 is pressed flat, and the support 24 is located between the two flat sections of the first tab 221 of the innermost circle", the support 24 is located between the first flat section 221a and the second flat section 221c of the first tab 221 of the innermost circle.

[0213] In the step "pre-pressing the electrode assembly 22 provided with the support 24", the pre-pressing pressure can be greater than or equal to 8T, at which the first corner section 221b is not prone to cracking.

[0214] In the above method for manufacturing the battery cell, when the electrode assembly 22 is pre-pressed, the stress on the first corner section 221b can be dispersed by the support 24 sharing the stress on the first flat section 221a and the second flat section 221c when they are folded, and the risk of stress concentration on the first corner section 221b is reduced. Therefore, when the electrode assembly 22 is pre-pressed and shaped, the risk of the electrode assembly 22 opening can be reduced by increasing the pre-pressing pressure, and the first corner section 221b is not prone to cracking, so that the battery cell 20 has high reliability, thereby improving the reliability of the battery device 100 constituted by the battery cell 20.

[0215] According to some embodiments of the present application, the step "S100, the first tab 221, the separator 222, and the second tab 223 are wound into an electrode assembly 22" comprises:

[0216] The first tab 221, the separator 222, and the second tab 223 are wound on the winding needle.

[0217] The step "S200, the support 24 is provided inside the first tab 221 of the innermost circle" comprises:

[0218] The support 24 is inserted inside the first tab 221 of the innermost circle while the winding needle is withdrawn from the electrode assembly 22; or,

[0219] The support 24 is inserted inside the first tab 221 of the innermost circle after the winding needle is withdrawn from the electrode assembly 22.

[0220] Wherein, after the first tab 221, the separator 222, and the second tab 223 are wound on the winding needle, the electrode assembly 22 is in a hollow cylindrical shape, before the winding needle is withdrawn, a pair of clamping needles of the winding needle move away from each other in the radial direction of the winding needle, stretching the cylindrical electrode assembly 22 into an elliptical shape, and then the pair of clamping needles are withdrawn from the electrode assembly 22.

[0221] The step "S200, arranging the support 24 inside the first pole piece 221 of the innermost winding" can be performed while the winding needle is being withdrawn, i.e., the support 24 is inserted into the inside of the first pole piece 221 of the innermost winding while the winding needle is being withdrawn; or the step "S200, arranging the support 24 inside the first pole piece 221 of the innermost winding" can be performed after the winding needle is withdrawn, i.e., the support 24 is inserted into the inside of the first pole piece 221 of the innermost winding after the winding needle is withdrawn from the electrode assembly 22.

[0222] Inserting the support 24 into the inside of the first pole piece 221 of the innermost winding while the winding needle is being withdrawn from the electrode assembly 22 can improve the assembly efficiency and shorten the assembly time. Inserting the support 24 into the inside of the first pole piece 221 of the innermost winding after the winding needle is withdrawn from the electrode assembly 22 facilitates the arrangement of the support 24.

[0223] According to some embodiments of the present application, please refer to Figure 3 to Figure 8 The battery cell 20 provided by the embodiments of the present application includes a shell 21, an electrode assembly 22, and a support 24. The electrode assembly 22 is arranged in the shell 21, and the electrode assembly 22 has a winding structure. The electrode assembly 22 includes a first pole piece 221 and a second pole piece 223, and the second pole piece 223 has a polarity opposite to that of the first pole piece 221. The first pole piece 221 of the innermost winding includes a first flat section 221a, a first corner section 221b, a second flat section 221c, and a second corner section 221d. One end of the first flat section 221a is a winding start end of the first pole piece 221. The first corner section 221b connects the first flat section 221a and the second flat section 221c. The second corner section 221d is connected to one end of the second flat section 221c away from the first corner section 221b. The support 24 is arranged between the first flat section 221a and the second flat section 221c in the thickness direction Z of the electrode assembly.

[0224] In the first direction X, the support 24 has a first end 24a close to the first corner section 221b and a second end 24b away from the first corner section 221b. The distance between the first end 24a and the outside vertex of the first corner section 221b is L1, and the distance between the second end 24b and the outside vertex of the second corner section 221d is L2. It is satisfied that 0 < L1 ≤ 15 mm and 0 < L2 ≤ 15 mm.

[0225] The first end 24a is arranged corresponding to the first corner section 221b, and the second end 24b is arranged corresponding to the second corner section 221d. When the electrode assembly 22 is pre-pressed, the support 24 can absorb the pressure when the first flat section 221a and the second flat section 221c are folded, can disperse the stress on the first corner section 221b and the second corner section 221d, can reduce the stress concentration of the first corner section 221b and the second corner section 221d, can reduce the risk of cracking of the first corner section 221b and the second corner section 221d, and thus can improve the reliability of the battery monomer 20.

[0226] In the present application, the electrode assembly 22 with or without the support 24 is subjected to the experiments of embodiments 1-4 and comparative examples 1-2. The electrode assembly 22 with the support 24 is subjected to the pre-pressing experiments with different pre-pressing pressures in embodiments 1-4, and the electrode assembly 22 without the support 24 is subjected to the pre-pressing experiments with different pre-pressing pressures in comparative examples 1 and 2. The electrode assembly 22 is a cuboid, the size of the electrode assembly 22 in the first direction X is 213 mm, the number of layers of the second tab 223 (positive electrode tab) of the electrode assembly 22 is 53 layers, and the thickness of the electrode assembly 22 is 17.7 mm. The support 24 is arranged between the first flat section 221a and the second flat section 221c of the first tab 221 (negative electrode tab) of the innermost circle. The distance L1 between the first end 24a of the support 24 and the outer side vertex of the first corner section 221b is 2 mm, and the distance L2 between the second end 24b and the outer side vertex of the second corner section 221d is 2 mm. In comparative examples 1-2 and embodiments 1-4, 10 electrode assemblies 22 are tested, the pre-pressing time is 15 s, the pre-pressing opening rates of the 10 electrode assemblies 22 are obtained, the pre-pressing opening rate is the proportion of the open electrode assemblies 22 in the 10 electrode assemblies 22, and the first corner section 221b of the pre-pressed electrode assembly 22 is subjected to the cracking detection. The CT scanning is performed to detect whether the first corner section 221b is cracked, and the experimental data in Table 1 is obtained.

[0227] Table 1

[0228] Pre-pressing pressure (T) Pre-pressing opening rate First corner section 221b breakage Comparative Example 1 6 70％ No Comparative Example 2 8 30％ Yes Example 1 8 30％ No Example 2 8.5 10％ No Example 3 9 3％ No Example 4 10 0％ No

[0229] According to the above table, in comparative examples 1 and 2 without the support 24, the pre-pressing opening of the electrode assembly 22 can be improved by increasing the pre-pressing pressure. However, when the pre-pressing pressure is increased, for example, the pre-pressing pressure reaches 8T, the first corner section 221b of the electrode assembly 22 is cracked. However, in embodiments 1-4 with the support 24, the pre-pressing opening of the electrode assembly 22 can be improved by increasing the pre-pressing pressure (such as increasing to 8T or more), the first corner section 221b of the electrode assembly 22 is not easy to crack, and the battery monomer 20 can have high reliability.

[0230] Although the present application has been described with reference to preferred embodiments, various modifications can be made to the application without departing from the scope of the application. In particular, the technical features mentioned in the various embodiments can be combined in any way, provided that there is no structural conflict. The present application 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, characterized by, The application relates to a battery, comprising: a shell; an electrode assembly arranged in the shell, the electrode assembly being in a winding structure, the electrode assembly comprising a first tab, the first tab in an innermost circle comprising a first flat section, a first corner section and a second flat section, one end of the first flat section being a winding start end of the first tab, the first corner section connecting the first flat section and the second flat section; a support arranged between the first flat section and the second flat section in the thickness direction of the electrode assembly.

2. The battery cell of claim 1, wherein, The support is in a sheet shape, and the thickness direction of the support is parallel to the thickness direction of the electrode assembly.

3. The battery cell of claim 2, wherein, The thickness of the support is H, and 1mm<=H<=5mm.

4. The battery cell of claim 3, wherein, 1mm<=H<=3mm.

5. The battery cell of claim 2, wherein, The first tab in the innermost circle further comprises a second corner section connected to one end of the second flat section away from the first corner section; in a first direction, the support has a first end close to the first corner section and a second end away from the first corner section, the first direction, the thickness direction of the electrode assembly and the winding axis direction of the electrode assembly being perpendicular to each other; in the first direction, the distance between the first end and the outside vertex of the first corner section is L1, and the distance between the second end and the outside vertex of the second corner section is L2, and 0 6. The battery cell of claim 5, wherein, 2mm<=L1<=10mm, and 2mm<=L2<=10mm.

7. The battery cell of claim 1, wherein, The first tab in the innermost circle further comprises a second corner section connected to one end of the second flat section away from the first corner section; in a first direction, the size of the support is W1, and the distance between the outside vertex of the first corner section and the outside vertex of the second corner section is W2, and 0.5<=W1 / W2<1, the first direction, the thickness direction of the electrode assembly and the winding axis direction of the electrode assembly being perpendicular to each other.

8. The battery cell of claim 7, wherein, 0.9<=W1 / W2<1.

9. The battery cell of claim 1, wherein, The support comprises two sub-supports, and the two sub-supports are arranged in a first direction, the first direction, the thickness direction of the electrode assembly and the winding axis direction of the electrode assembly being perpendicular to each other.

10. The battery cell of claim 9, wherein, in the first direction, the size of the sub-support is W3, and 5mm<=W3<=50mm.

11. The battery cell of claim 10, wherein, 10mm<=W3<=30mm.

12. The battery cell of claim 1, wherein, The first tab comprises a first main body and a first tab ear, and the first tab ear extends from the end of the first main body in the winding axis direction of the electrode assembly; in the winding axis direction of the electrode assembly, the size of the first main body is K1, and the size of the support is K2, and 0.5<=K2 / K1<=1.

13. The battery cell of claim 12, wherein, 0.8<=K2 / K1<=1.

14. The battery cell of claim 1, wherein, The support is an insulating sheet.

15. The battery cell of claim 14, wherein, The density of the support is 0.8 g / cm 3 ~ 2.2 g / cm 3 .

16. The battery cell of claim 14, wherein, The material of the support is polytetrafluoroethylene, polyvinyl chloride, polypropylene or polycarbonate.

17. The battery cell of any one of claims 1-16, wherein, The electrode assembly includes a second tab, the second tab being opposite in polarity to the first tab, the second tab of the innermost turn including a third flat section, a third corner section, and a fourth flat section, one end of the third flat section being a winding start end of the second tab, the third corner section connecting the third flat section and the fourth flat section; In a thickness direction of the electrode assembly, the first flat section and the second flat section are located between the third flat section and the fourth flat section, and the first corner section is located inside the third corner section.

18. The battery cell of any one of claims 1-16, wherein, The electrode assembly includes a second tab, the second tab being opposite in polarity to the first tab, the second tab of the innermost turn including a third flat section, a third corner section, and a fourth flat section, one end of the third flat section being a winding start end of the second tab, the third corner section connecting the third flat section and the fourth flat section; In a thickness direction of the electrode assembly, the first flat section is located between the third flat section and the fourth flat section, the third flat section is located between the first flat section and the second flat section, and the support member is disposed between the first flat section and the third flat section.

19. A battery device characterized by comprising: A battery cell including the electrode assembly of any one of claims 1-18.

20. An electrical device, comprising: A battery device including the battery cell of claim 19.

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