Electrode assembly and manufacturing method thereof, battery cell, battery device, and electric device

Abstract

The invention provides an electrode assembly and a manufacturing method thereof, a battery monomer, a battery device and a power utilization device, and relates to the field of batteries. The battery monomer comprises a shell, an electrode assembly and an elastic layer, the electrode assembly is accommodated in the shell and comprises a positive plate, a separator and a negative plate, and the separator is arranged between the positive plate and the negative plate. The elastic layer is arranged between the positive plate and the negative plate, and the elastic layer is configured to be capable of being compressed so as to provide an expansion space for the positive plate and / or the negative plate. In the cycle process of the battery monomers, the positive plate and / or the negative plate are / is expanded, and the elastic layer can be compressed under the action of the positive plate and / or the negative plate, so that an expansion space is provided for the positive plate and / or the negative plate, the stress concentration phenomenon of the pole plates is relieved, the risk of breakage of the pole plates is reduced, and the service life of the battery monomers is prolonged. The risk that burrs and chippings generated at the fracture position pierce the separator is reduced, so that the positive plate and the negative plate are not easy to contact and short circuit, and the reliability of the battery device is improved.

Description

Technical Field

[0001] This application relates to the field of batteries, and more specifically, to an electrode assembly and its manufacturing method, a battery cell, a battery device, and an electrical device. Background Technology

[0002] Batteries are widely used in the new energy field, such as in electric vehicles and new energy vehicles, which have become a new trend in the automotive industry. The development of battery technology must consider multiple design factors simultaneously, such as energy density, cycle life, discharge capacity, and charge / discharge rate. Additionally, battery reliability must also be considered. However, current battery reliability is relatively poor. Summary of the Invention

[0003] The purpose of this application is to provide an electrode assembly and its manufacturing method, a battery cell, a battery device, and an electrical device, which aim to improve the problem of poor battery reliability in related technologies.

[0004] In a first aspect, embodiments of this application provide a battery cell, the battery cell including a casing, an electrode assembly and an elastic layer, the electrode assembly being housed within the casing, the electrode assembly including a positive electrode, a separator and a negative electrode, the separator being disposed between the positive electrode and the negative electrode; the elastic layer being disposed between the positive electrode and the negative electrode, the elastic layer being configured to be compressible to provide expansion space for the positive electrode and / or the negative electrode.

[0005] In the above technical solution, an elastic layer is provided between the positive and negative electrode plates of the battery cell. During the cycling process of the battery cell, the positive and / or negative electrode plates expand, and the elastic layer can be compressed under the action of the positive and / or negative electrode plates, thereby providing expansion space for the positive and / or negative electrode plates. This helps to alleviate the phenomenon of stress concentration on the electrode plates, reduces the risk of electrode plate breakage, and also reduces the risk of burrs and debris generated at the breakage location piercing the separator. This makes it less likely for the positive and negative electrode plates to come into contact and short-circuit, thus improving the reliability of the battery device.

[0006] As an optional technical solution in this application embodiment, the positive electrode sheet, the separator and the negative electrode sheet are wound together; the electrode assembly includes a flat region and a bent region connected to the flat region, and the elastic layer is disposed at least in the bent region.

[0007] In the above technical solution, the positive electrode, separator, and negative electrode are wound together, resulting in a wound electrode assembly. For wound electrode assemblies, the outer electrode layer cannot expand outwards due to the characteristics of the wound structure and the constraint of the battery cell's outer shell. As the inner electrode layer expands outwards, stress concentration becomes more pronounced. By placing an elastic layer at least in the bending area, during battery cell cycling, the positive and / or negative electrode expands, and the elastic layer can be compressed under the action of the positive and / or negative electrode, thus providing expansion space for the positive and / or negative electrode, effectively alleviating stress concentration and improving the reliability of the battery device.

[0008] As an optional technical solution in this application embodiment, the elastic layer is only disposed in the bending area.

[0009] In the above technical solution, the elastic layer exists only in the bending area and not in the straight area. On the one hand, the positive electrode, separator, and negative electrode located in the straight area can adhere tightly together, and the positive electrode, separator, and negative electrode can expand synchronously without wrinkling, further improving the reliability of the battery device. On the other hand, it can reduce the space occupied by the elastic layer, which is beneficial to improving the energy density of the battery cell.

[0010] As an optional technical solution in this application embodiment, the elastic layer is disposed in the bending area and the straight area.

[0011] In the above technical solution, by setting the elastic layer in the bending area and the straight area, when the positive electrode and / or negative electrode expand, the elastic layer can be compressed under the action of the positive electrode and / or negative electrode, thereby providing a larger expansion space for the positive electrode and / or negative electrode, effectively alleviating the phenomenon of electrode stress concentration, and improving the reliability of the battery device.

[0012] As an optional technical solution in this application embodiment, the positive electrode includes a plurality of first electrode segments located in the bending region, and the negative electrode includes a plurality of second electrode segments located in the bending region; an elastic layer is disposed between each adjacent first electrode segment and second electrode segment.

[0013] In the above technical solution, by providing an elastic layer between each adjacent first electrode segment and second electrode segment, when the positive electrode and / or negative electrode expand, each elastic layer can be compressed under the action of the positive electrode and / or negative electrode, thereby providing a larger expansion space for the positive electrode and / or negative electrode, effectively alleviating the phenomenon of electrode stress concentration, and improving the reliability of the battery device.

[0014] As an optional technical solution in this application embodiment, the elastic layer is disposed on at least one side of the isolation member.

[0015] In the above technical solution, by providing an elastic layer on at least one side of the separator, on the one hand, the elastic layer is less likely to adhere to the active material layer, thus having less impact on the active material layer of the positive and / or negative electrode sheets. On the other hand, providing the elastic layer on the separator and coating the current collector with the active material slurry can be manufactured in parallel, which helps to shorten the manufacturing cycle and reduce manufacturing costs.

[0016] As an optional technical solution in this application embodiment, the isolation member includes a plurality of first isolation segments located in the bending area, at least one of the first isolation segments is provided with the elastic layer, the first isolation segment has a first surface along its thickness direction, and the elastic layer completely covers the first surface.

[0017] In the above technical solution, the elastic layer completely covers the first surface. During manufacturing, the slurry can be applied to the first surface in a continuous coating manner to form the elastic layer, making the manufacturing process simpler and more convenient.

[0018] As an optional technical solution in this application embodiment, the isolation member includes a plurality of first isolation segments located in the bending area, and a plurality of elastic layers are provided on at least one side of at least one of the first isolation segments, and the plurality of elastic layers located on the same side of the first isolation segment are spaced apart along the extension direction of the first isolation segment.

[0019] In the above technical solution, by setting multiple elastic layers at intervals on the same side of the first isolation section, the gap between two adjacent elastic layers can also serve as an expansion space. This helps to reduce the material consumption of the elastic layers and reduce the manufacturing cost of the electrode assembly.

[0020] As an optional technical solution in this application embodiment, the elastic layer is disposed on at least one side of the isolation member.

[0021] In the above technical solution, by providing an elastic layer on at least one side of the separator, on the one hand, the elastic layer is less likely to adhere to the active material layer, thus having less impact on the active material layer of the positive and / or negative electrode sheets. On the other hand, providing the elastic layer on the separator and coating the current collector with the active material slurry can be manufactured in parallel, which helps to shorten the manufacturing cycle and reduce manufacturing costs.

[0022] As an optional technical solution in this application embodiment, the elastic modulus of the elastic layer is A, which satisfies: 1Mpa≤A≤10Mpa.

[0023] In the above technical solution, when A ≥ 1 MPa, the elastic modulus of the elastic layer is relatively large. Thus, during the winding or stacking of the positive electrode, separator, and negative electrode, the elastic layer can withstand the compressive force generated by winding or stacking, while retaining elastic deformation margin. During the cycle of a single battery cell, the positive electrode and / or negative electrode expand, and the elastic layer can be compressed under the action of the positive electrode and / or negative electrode, thereby providing expansion space for the positive electrode and / or negative electrode, effectively alleviating the phenomenon of electrode stress concentration and improving the reliability of the battery device. When A ≤ 100 MPa, the elastic modulus of the elastic layer is not excessively large, thus facilitating the winding or stacking of the positive electrode, separator, and negative electrode. Furthermore, the elastic layer can be compressed under the action of the positive electrode and / or negative electrode, thereby providing expansion space for the positive electrode and / or negative electrode. Therefore, when 1 MPa ≤ A ≤ 10 MPa, it is easy to wind or stack positive electrode sheets, separators and negative electrode sheets. When the positive electrode sheet and / or negative electrode sheet expands, the elastic layer can be compressed under the action of the positive electrode sheet and / or negative electrode sheet, thereby providing expansion space for the positive electrode sheet and / or negative electrode sheet, effectively alleviating the phenomenon of electrode stress concentration and improving the reliability of the battery device.

[0024] As an optional technical solution in this application embodiment, the elastic layer is a coating disposed on at least one of the positive electrode sheet, the separator and the negative electrode sheet.

[0025] In the above technical solution, the elastic layer is a coating. On the one hand, the elastic layer can be manufactured by coating, which is simple and convenient and facilitates mass production. On the other hand, the thickness of the elastic layer is easy to control, reducing space occupation while allowing for expansion space, which is beneficial to improving energy density.

[0026] As an optional technical solution in this application embodiment, the thickness of the elastic layer is H, which satisfies: 10μm≤H≤100μm.

[0027] In the above technical solutions, when H ≥ 10 μm, the elastic layer has a relatively large thickness, providing ample expansion space when compressed. This helps alleviate stress concentration on the electrode, reduces the risk of electrode breakage, and improves the reliability of the battery device. When H ≤ 100 μm, the elastic layer thickness is not excessive, allowing for a shorter ion pathway between the positive and negative electrodes. This helps reduce the internal resistance of the battery cell and improves its charge / discharge rate. Therefore, when 10 μm ≤ H ≤ 100 μm, it provides both a larger expansion space for electrode expansion and a shorter ion pathway between the positive and negative electrodes.

[0028] As an optional technical solution in this application embodiment, 30μm≤H≤60μm.

[0029] In the above technical solutions, when H ≥ 30 μm, the elastic layer is thicker, providing greater expansion space when compressed. This helps alleviate stress concentration on the electrode, reduces the risk of electrode breakage, and improves the reliability of the battery device. When H ≤ 60 μm, the elastic layer thickness is not excessive, allowing for a shorter ion pathway between the positive and negative electrodes. This reduces the internal resistance of the battery cell and increases its charge / discharge rate. Therefore, when 30 μm ≤ H ≤ 60 μm, it provides both a larger expansion space for electrode expansion and a shorter ion pathway between the positive and negative electrodes.

[0030] As an optional technical solution in this application embodiment, the elastic layer includes a plurality of elastic units, and channels for metal ions to pass through are formed between the plurality of elastic units. The elastic units contain an electrolyte, and the elastic units are configured to release the electrolyte when they rupture.

[0031] In the above technical solution, during the cycling process of a single battery cell, the positive and / or negative electrode plates expand, which can easily squeeze out the electrolyte between the positive and negative electrode plates, resulting in poor wetting of the electrode plates and leading to lithium plating. By containing the electrolyte within an elastic cell, when the positive and / or negative electrode plates expand, the elastic layer can be compressed under the action of the positive and / or negative electrode plates. When the pressure on the elastic cell exceeds a threshold, the elastic cell ruptures, releasing the electrolyte. The electrolyte can then continue to wet the electrode plates, thereby reducing the risk of lithium plating and improving the reliability of the battery cell.

[0032] As an optional technical solution in this application embodiment, the strength of the elastic element is B, which satisfies: 0.1Mpa≤B≤10Mpa.

[0033] In the above technical solution, when B ≥ 0.1 MPa, the elastic unit has high strength. Thus, during the winding or stacking of the positive electrode, separator, and negative electrode, the elastic unit can withstand the compressive force generated by the winding or stacking without breaking, preventing premature consumption of the electrolyte encapsulated within the elastic unit. When B ≤ 10 MPa, the strength of the elastic unit is not excessively high, allowing it to be crushed under the action of the positive and / or negative electrode, releasing the electrolyte. The electrolyte can then continue to wet the electrode, reducing the risk of lithium plating and improving the reliability of the battery cell. Therefore, when 0.1 MPa ≤ B ≤ 10 MPa, the elastic element can break at a more appropriate time, releasing the electrolyte to wet the electrode.

[0034] As an optional technical solution in this application embodiment, 0.1Mpa≤B≤1Mpa.

[0035] In the above technical solution, when B ≥ 0.1 MPa, the elastic unit has high strength. This allows the elastic unit to withstand the compressive force generated during winding or stacking of the positive electrode, separator, and negative electrode without breaking, preventing premature consumption of the electrolyte encapsulated within the elastic unit. When B ≤ 1 MPa, the strength of the elastic unit is not excessively high, allowing it to be crushed under the action of the positive and / or negative electrode, releasing the electrolyte. The electrolyte can then continue to wet the electrode, reducing the risk of lithium plating and improving the reliability of the battery cell. Therefore, when 0.1 MPa ≤ B ≤ 1 MPa, the elastic element is more likely to break at a more appropriate time, releasing the electrolyte to wet the electrode.

[0036] As an optional technical solution in this application embodiment, the elastic unit is spherical, and the outer diameter of the elastic unit is D, which satisfies: 5μm≤D≤60μm.

[0037] In the above technical solution, when D ≥ 5 μm, the outer diameter of the elastic unit is relatively large, resulting in a larger gap between multiple elastic units. This facilitates the formation of a larger ion pathway, allowing ions to pass through. When D ≤ 60 μm, the outer diameter of the elastic unit is not too large, allowing for a smaller elastic layer thickness. This results in a shorter ion pathway between the positive and negative electrodes, which helps reduce the internal resistance of the battery cell and improve its charge / discharge rate. Therefore, when 5 μm ≤ D ≤ 60 μm, both a larger and shorter ion pathway can be formed, which is beneficial for reducing the internal resistance of the battery cell and improving its charge / discharge rate.

[0038] As an optional technical solution in this application embodiment, 10μm≤D≤30μm.

[0039] In the above technical solution, when D ≥ 10 μm, the outer diameter of the elastic unit is larger, resulting in a larger gap between multiple elastic units. This is more conducive to forming a larger ion pathway, facilitating ion passage. When D ≤ 30 μm, the outer diameter of the elastic unit is not too large, allowing for a smaller elastic layer thickness. This results in a shorter ion pathway between the positive and negative electrodes, which helps reduce the internal resistance of the battery cell and improve its charge / discharge rate. Therefore, when 10 μm ≤ D ≤ 30 μm, both a larger and shorter ion pathway can be formed, which is beneficial for reducing the internal resistance of the battery cell and improving its charge / discharge rate.

[0040] As an optional technical solution in this application embodiment, the material of the elastic unit includes at least one of polyvinyl alcohol, silicone, polyurethane, and polylactic acid.

[0041] Among the above technical solutions, polyvinyl alcohol, silicone, polyurethane, and polylactic acid are low in cost and highly elastic, which allows the resulting elastic layer to provide a large expansion space.

[0042] Secondly, embodiments of this application also provide an electrode assembly, the electrode assembly including a positive electrode sheet, a separator, a negative electrode sheet and an elastic layer, the separator being disposed between the positive electrode sheet and the negative electrode sheet, the elastic layer being disposed between the positive electrode sheet and the negative electrode sheet, the elastic layer being configured to be compressible to provide expansion space for the positive electrode sheet and / or the negative electrode sheet.

[0043] As an optional technical solution in this application embodiment, the positive electrode sheet, the separator and the negative electrode sheet are wound together; the electrode assembly includes a flat region and a bent region connected to the flat region, and the elastic layer is disposed at least in the bent region.

[0044] In the above technical solution, the positive electrode, separator, and negative electrode are wound together, resulting in a wound electrode assembly. For wound electrode assemblies, the outer electrode layer cannot expand outwards due to the characteristics of the wound structure and the constraint of the battery cell's outer shell. As the inner electrode layer expands outwards, stress concentration becomes more pronounced. By placing an elastic layer at least in the bending area, during battery cell cycling, the positive and / or negative electrode expands, and the elastic layer can be compressed under the action of the positive and / or negative electrode, thus providing expansion space for the positive and / or negative electrode, effectively alleviating stress concentration and improving the reliability of the battery device.

[0045] As an optional technical solution in this application embodiment, the elastic layer includes a plurality of elastic units, and channels for metal ions to pass through are formed between the plurality of elastic units. The elastic units contain an electrolyte, and the elastic units are configured to release the electrolyte when they rupture.

[0046] In the above technical solution, during the cycling process of a single battery cell, the positive and / or negative electrode plates expand, which can easily squeeze out the electrolyte between the positive and negative electrode plates, resulting in poor wetting of the electrode plates and leading to lithium plating. By containing the electrolyte within an elastic cell, when the positive and / or negative electrode plates expand, the elastic layer can be compressed under the action of the positive and / or negative electrode plates. When the pressure on the elastic cell exceeds a threshold, the elastic cell ruptures, releasing the electrolyte. The electrolyte can then continue to wet the electrode plates, thereby reducing the risk of lithium plating and improving the reliability of the battery cell.

[0047] Thirdly, embodiments of this application also provide a method for manufacturing an electrode assembly, the method comprising: step S100: providing a positive electrode sheet, an separator, and a negative electrode sheet; step S200: disposing an elastic layer on at least one of the positive electrode sheet, the separator, and the negative electrode sheet; step S300: winding or stacking the positive electrode sheet, the separator, and the negative electrode sheet to form the electrode assembly, wherein the elastic layer is disposed between the positive electrode sheet and the negative electrode sheet, and the elastic layer is configured to be compressible to provide expansion space for the positive electrode sheet and / or the negative electrode sheet.

[0048] As an optional technical solution in an embodiment of this application, step S200 includes: step S210: coating a paste onto at least one of the positive electrode, the separator, and the negative electrode to form the elastic layer.

[0049] In the above technical solution, an elastic layer is formed on at least one of the positive electrode, the separator, and the negative electrode by coating a slurry onto them. This method is simple and convenient to manufacture, facilitating mass production. Furthermore, the thickness of the elastic layer is easy to control, reducing space occupation while allowing for expansion, which is beneficial for improving energy density.

[0050] As an optional technical solution in an embodiment of this application, step S210 includes: step S211: coating the slurry on at least one side of the insulating member to form the elastic layer.

[0051] In the above technical solution, by coating at least one side of the separator with a slurry to form an elastic layer, on the one hand, the elastic layer is less likely to adhere to the active material layer, thus having less impact on the active material layer of the positive and / or negative electrode sheets. On the other hand, the elastic layer on the separator and the active material slurry coating on the current collector can be manufactured in parallel, which helps to shorten the manufacturing cycle and reduce manufacturing costs.

[0052] As an optional technical solution in an embodiment of this application, step S300 includes: step S310: winding the positive electrode sheet, the separator and the negative electrode sheet to form an electrode assembly, the electrode assembly including a flat region and a bent region connected to the flat region, and the elastic layer being disposed at least in the bent region.

[0053] In the above technical solution, the positive electrode, separator, and negative electrode are wound together, resulting in a wound electrode assembly. For wound electrode assemblies, the outer electrode layer cannot expand outwards due to the characteristics of the wound structure and the constraint of the battery cell's outer shell. As the inner electrode layer expands outwards, stress concentration becomes more pronounced. By placing an elastic layer at least in the bending area, during battery cell cycling, the positive and / or negative electrode expands, and the elastic layer can be compressed under the action of the positive and / or negative electrode, thus providing expansion space for the positive and / or negative electrode, effectively alleviating stress concentration and improving the reliability of the battery device.

[0054] As an optional technical solution in this application embodiment, the isolation member includes a first region and a second region. Along the length direction of the isolation member, the first region and the second region are alternately arranged. In the electrode assembly, the first region is located in the straight region, and the second region is located in the bending region. Step S200 includes: Step S220: continuously coating a slurry on at least one side of the second region to form the elastic layer.

[0055] In the above technical solution, the slurry is applied to at least one side of the second region using a continuous coating method, which makes the manufacturing process simpler and more convenient.

[0056] As an optional technical solution in this application embodiment, the isolation member includes a first region and a second region. Along the length direction of the isolation member, the first region and the second region are alternately arranged. In the electrode assembly, the first region is located in the straight region, and the second region is located in the bending region. Step S200 includes: Step S230: Along the length direction of the isolation member, a slurry is applied at intervals on at least one side of the second region to form a plurality of elastic layers arranged at intervals.

[0057] In the above technical solution, the slurry is coated on at least one side of the second region using an intermittent coating method, which helps to reduce slurry consumption, reduce the raw material cost of the slurry, and reduce the manufacturing cost of the electrode assembly.

[0058] Fourthly, embodiments of this application also provide a battery device, the battery device comprising the aforementioned battery cell.

[0059] Fifthly, embodiments of this application also provide an electrical device, the electrical device including the aforementioned battery cell, the battery cell being used to provide electrical energy to the electrical device. Attached Figure Description

[0060] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0061] Figure 1 This application provides structural schematic diagrams of vehicles for some embodiments;

[0062] Figure 2 Exploded views of battery devices provided in some embodiments of this application;

[0063] Figure 3 This is a schematic diagram of the structure of a battery cell provided in some embodiments of this application;

[0064] Figure 4 Exploded views of a single battery cell provided in some embodiments of this application;

[0065] Figure 5 This is a schematic diagram of the structure of an electrode assembly provided in some embodiments of this application;

[0066] Figure 6 This is a schematic diagram of the unfolded structure of the isolation component provided in some embodiments of this application;

[0067] Figure 7 This is a schematic diagram of the structure of an electrode assembly provided in other embodiments of this application;

[0068] Figure 8 This is a schematic diagram of the unfolded structure of the isolation member provided in some other embodiments of this application;

[0069] Figure 9 This is a front view of the unfolded isolation member provided in some other embodiments of this application;

[0070] Figure 10 This application provides schematic diagrams of the structure of electrode assemblies in some of its embodiments.

[0071] Figure 11 Schematic diagram of the unfolded structure of the isolation member provided in some embodiments of this application;

[0072] Figure 12 Microscopic schematic diagram of the elastic layer provided in some embodiments of this application;

[0073] Figure 13 A schematic block diagram illustrating a method for manufacturing an electrode assembly according to some embodiments of this application;

[0074] Figure 14A schematic block diagram illustrating a method for manufacturing an electrode assembly according to other embodiments of this application;

[0075] Figure 15 A schematic block diagram illustrating a method for manufacturing an electrode assembly according to some embodiments of this application;

[0076] Figure 16 A schematic block diagram illustrating a method for manufacturing an electrode assembly according to further embodiments of this application;

[0077] Figure 17 Schematic block diagrams of electrode assembly manufacturing methods provided in some embodiments of this application;

[0078] Figure 18 This is a schematic block diagram illustrating a method for manufacturing an electrode assembly according to other embodiments of this application.

[0079] Icons: 10-Box; 11-First part; 12-Second part; 20-Battery cell; 21-Outer shell; 211-Housing shell; 212-End cap; 22-Electrode assembly; 221-Main body; 2211-Straight area; 2212-Bending area; 222-Taper; 223-Positive electrode; 2231-First electrode segment; 224-Separator; 2241-First region; 2242-Second region; 2243-First separator; 225-Negative electrode; 2251-Second electrode segment; 226-Elastic layer; 2261-Elastic unit; 23-Insulator; 24-Electrode terminal; 30-Electrode assembly manufacturing method; 100-Battery device; 200-Controller; 300-Motor; 1000-Vehicle. Detailed Implementation

[0080] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0081] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the description of this application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms "comprising" and "having," and any variations thereof, in the description, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the description, claims, or accompanying drawings of this application are used to distinguish different objects, not to describe a specific order or hierarchy.

[0082] In this application, the reference to "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments.

[0083] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "attachment" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0084] In this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0085] In the embodiments of this application, the same reference numerals denote the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width, and other dimensions of various components in the embodiments of this application shown in the accompanying drawings, as well as the overall thickness, length, width, and other dimensions of the integrated device, are merely illustrative and should not constitute any limitation on this application.

[0086] In this application, "multiple" means two or more (including two).

[0087] In this embodiment of the application, the battery cell can be a secondary battery, which refers to a battery cell that can be recharged to activate the active materials and continue to be used after the battery cell has been discharged.

[0088] Battery cells include, but are not limited to, lithium-ion batteries, sodium-ion batteries, sodium-lithium-ion batteries, lithium metal batteries, sodium metal batteries, lithium-sulfur batteries, magnesium-ion batteries, nickel-metal hydride batteries, nickel-cadmium batteries, lead-acid batteries, etc.

[0089] A single battery cell typically includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator. During the charging and discharging process of a single battery cell, active ions (such as lithium ions) repeatedly insert and extract between the positive and negative electrodes. The separator, positioned between the positive and negative electrodes, reduces the risk of short circuits while allowing active ions to pass through.

[0090] In some embodiments, the positive electrode may be a positive electrode sheet, which may include a positive electrode current collector and a positive electrode active material disposed on at least one surface of the positive electrode current collector.

[0091] As an example, the positive current collector has two surfaces opposite each other in its own thickness direction, and the positive active material is disposed on either or both of the two opposite surfaces of the positive current collector.

[0092] As an example, the positive electrode current collector can be a metal foil or a composite current collector. For example, as a metal foil, it can be aluminum with a silver-plated surface, stainless steel with a silver-plated surface, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel, or titanium, etc. Composite current collectors can include a polymer material base layer and a metal layer. Composite current collectors 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 substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0093] As an example, the positive electrode active material may include at least one of the following materials: lithium phosphate, lithium transition metal oxide, and their respective modified compounds. However, this application is not limited to these materials, and other conventional materials that can be used as positive electrode active materials in battery cells may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium phosphate may include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO4), lithium manganese phosphate and carbon composites, lithium iron manganese phosphate, and lithium iron manganese phosphate and carbon composites. Examples of lithium transition metal oxide may include, but are not limited to, lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, and lithium nickel cobalt manganese oxide (such as LiNi). 1 / 3 Co 1 / 3Mn 1 / 3 O2 (also known as NCM) 333 LiNi 0.5 Co 0.2 Mn 0.3 O2 (also known as NCM) 523 LiNi 0.5 Co 0.25 Mn 0.25 O2 (also known as NCM) 211 LiNi 0.6 Co 0.2 Mn 0.2O2 (also known as NCM) 622 LiNi 0.8 Co 0.1 Mn 0.1 O2 (also known as NCM) 811 ), lithium nickel cobalt aluminum oxide (such as LiNi) 0.85 Co 0.15 Al 0.05 At least one of O2 and its modified compounds.

[0094] In some embodiments, the positive electrode can be a foamed metal. The foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloys, etc. When foamed metal is used as the positive electrode, the surface of the foamed metal may or may not contain a positive electrode active material. As an example, lithium source material, potassium metal, or sodium metal can also be filled and / or deposited within the foamed metal, where the lithium source material is lithium metal and / or a lithium-rich material.

[0095] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0096] As an example, the negative electrode current collector can be a metal foil, a foamed metal, or a composite current collector. For example, as a metal foil, it can be aluminum with a silver-plated surface, stainless steel with a silver-plated surface, stainless steel, copper, aluminum, nickel, carbon electrodes, carbon, nickel, or titanium, etc. Foamed metal can be nickel foam, copper foam, aluminum foam, foam alloy, etc. Composite current collectors can include a polymer material base layer and a metal layer. Composite current collectors can be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0097] As an example, the negative electrode sheet may include a negative electrode current collector and a negative electrode active material disposed on at least one surface of the negative electrode current collector.

[0098] As an example, the negative electrode current collector has two surfaces opposite each other in its own thickness direction, and the negative electrode active material is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0099] As an example, the negative electrode active material may be a negative electrode active material known in the art for use in battery cells. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate, etc. Silicon-based materials may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. Tin-based materials may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, this application is not limited to these materials, and other conventional materials that can be used as negative electrode active materials in battery cells may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0100] In some embodiments, the positive current collector can be made of aluminum, and the negative current collector can be made of copper.

[0101] In some embodiments, the separator is a separator membrane. The separator membrane can be any known porous structure separator membrane with good chemical and mechanical stability.

[0102] As an example, the material of the separator may include at least one of glass fiber, nonwoven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator may be a single-layer film or a multi-layer composite film. When the separator is a multi-layer composite film, the materials of each layer may be the same or different. The separator may be a separate component located between the positive and negative electrodes, or it may be attached to the surfaces of the positive and negative electrodes.

[0103] In some embodiments, the battery cell also includes an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. The electrolyte can be liquid, gel-like, or solid. Liquid electrolytes include electrolyte salts and solvents.

[0104] In some embodiments, the electrolyte salt may include at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalate borate, lithium dioxalate borate, lithium difluorodioxalate phosphate, and lithium tetrafluorooxalate phosphate.

[0105] In some embodiments, the solvent may include at least one selected from ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butyl carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone. The solvent may also be an ether solvent. Ether solvents may include one or more selected from ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyl tetrahydrofuran, diphenyl ether, and crown ethers.

[0106] Among them, the gel electrolyte includes a polymer as the electrolyte backbone network, combined with an ionic liquid - lithium salt.

[0107] In some implementations, the electrode assembly is a wound structure. The positive and negative electrode sheets are wound into a wound structure.

[0108] In some implementations, the electrode assembly is a stacked structure.

[0109] As an example, multiple positive and negative electrodes can be set, and multiple positive and multiple negative electrodes can be stacked alternately.

[0110] As an example, multiple positive electrode plates can be provided, and negative electrode plates can be folded to form multiple stacked folded segments, with a positive electrode plate sandwiched between adjacent folded segments.

[0111] As an example, both the positive and negative electrode plates are folded to form multiple stacked folded segments.

[0112] As an example, multiple separators can be provided, each positioned between any adjacent positive or negative electrode plates.

[0113] As an example, the separators can be continuously arranged, either by folding or rolling between any adjacent positive or negative electrode plates.

[0114] In some embodiments, the electrode assembly can be cylindrical, flat, or polygonal, etc.

[0115] In some embodiments, the electrode assembly is provided with tabs that allow current to be drawn from the electrode assembly. The tabs include a positive tab and a negative tab.

[0116] In some embodiments, the battery cell may include a housing. The housing is used to encapsulate components such as electrode assemblies and electrolytes. The housing may be made of steel, aluminum, plastic (such as polypropylene), composite metal (such as copper-aluminum composite), or aluminum-plastic film, etc.

[0117] 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, it can protect the electrode assembly and prevent, to some extent, electrolyte leakage. When the housing is a non-sealed structure, it can still protect the electrode assembly, and a sealing bag may be included between the housing and the electrode assembly to encapsulate the electrode assembly and electrolyte. Specifically, the sealing bag can be a bag-shaped insulating component or an aluminum-plastic film.

[0118] As an example, a battery cell can be a cylindrical battery cell, a prismatic battery cell, a pouch battery cell, or a battery cell of other shapes. Prismatic battery cells include prismatic battery cells, blade-shaped battery cells, and multi-prismatic battery cells, such as hexagonal prismatic battery cells.

[0119] The battery apparatus mentioned in the embodiments of this application may include one or more battery cell assemblies for providing voltage and capacity. A battery cell assembly may include multiple battery cells, which are connected in series, parallel, or mixed connections via a busbar.

[0120] In some embodiments, a battery cell assembly is typically formed by arranging multiple battery cells; as an example, a battery cell assembly can be a battery module, which is formed by arranging multiple battery cells and fixing them together to form an independent module.

[0121] As an example, a battery module can be formed by bundling multiple battery cells together with cable ties.

[0122] In some embodiments, the battery device may be a battery pack, which may include a housing and one or more individual battery cells housed within the housing.

[0123] As an example, the battery cell assembly can be a battery module, which can be housed in a housing by fixing the battery module in the housing.

[0124] As an example, battery cell assemblies can also be housed in a housing by directly fixing multiple battery cells to the housing.

[0125] As an example, the enclosure may include a first part and a second part. The first and second parts are fastened together to form a closed space inside the enclosure to house the individual battery cells. Here, "closed" refers to covering or shutting off; it can be sealed or not sealed. The first part may be a top cover or a bottom plate.

[0126] As an example, the enclosure may include a top cover, a frame, and a bottom plate. The top cover and bottom plate are connected to the frame, creating an enclosed space inside the enclosure to house the individual battery cells.

[0127] As an example, the housing can be part of the vehicle's chassis structure. For instance, the housing's roof can be at least part of the vehicle's floor, or the housing's frame can be at least part of the vehicle's crossbeams and longitudinal beams.

[0128] In some embodiments, the battery device refers to an energy storage device, which includes a housing with a door on at least one side. Energy storage devices include energy storage containers, energy storage cabinets, etc.

[0129] Currently, judging from market trends, battery applications are becoming increasingly widespread. Batteries are not only used in energy storage systems such as hydropower, thermal power, wind power, and solar power plants, but also extensively in electric vehicles such as electric bicycles, electric motorcycles, and electric cars, as well as in military equipment and aerospace. With the continuous expansion of battery applications, market demand is also constantly increasing.

[0130] The development of battery technology must consider multiple design factors simultaneously, such as energy density, cycle life, discharge capacity, and charge / discharge rate. Additionally, battery reliability must also be considered. However, current battery reliability is relatively poor.

[0131] During the cyclic charging and discharging of a battery cell, the electrode assembly expands. The inner electrode plates gradually expand outwards, while the outer electrode plates, constrained by the battery cell's outer shell, cannot expand outwards. As the inner electrode plates expand outwards, stress concentration occurs, potentially leading to cracking. When a crack occurs, burrs and even metal debris are produced at the fracture surface. These burrs and debris may puncture the separator, causing the positive and negative electrode plates to overlap, resulting in a short circuit in the battery cell, potentially leading to a fire or even an explosion.

[0132] Therefore, embodiments of this application provide a battery cell, which includes a casing, an electrode assembly, and an elastic layer, with the electrode assembly housed within the casing. The electrode assembly includes a positive electrode, a separator, and a negative electrode, with the separator disposed between the positive and negative electrode. The elastic layer is disposed between the positive and negative electrode and is configured to be compressible to provide expansion space for the positive and / or negative electrode.

[0133] An elastic layer is provided between the positive and negative electrode plates of the battery cell. During the cycling process of the battery cell, the positive and / or negative electrode plates expand, and the elastic layer can be compressed under the action of the positive and / or negative electrode plates, thereby providing expansion space for the positive and / or negative electrode plates. This helps to alleviate the phenomenon of stress concentration on the electrode plates, reduces the risk of electrode plate breakage, and also reduces the risk of burrs and debris generated at the breakage location piercing the separator. This makes it less likely for the positive and negative electrode plates to come into contact and short-circuit, thus improving the reliability of the battery device.

[0134] The technical solutions described in the embodiments of this application are applicable to various electrical devices that use battery cells and battery devices, such as mobile phones, portable devices, laptops, electric vehicles, electric toys, power tools, vehicles, ships and spacecraft, etc. For example, spacecraft include airplanes, rockets, space shuttles and spacecraft.

[0135] For ease of explanation, the following embodiments will use a vehicle as an example of an electrical device.

[0136] Please refer to Figure 1 , Figure 1 This is a schematic diagram of the structure of a vehicle 1000 provided in some embodiments of this application. A battery device 100 is disposed inside the vehicle 1000, and the battery device 100 may be located at the bottom, front, or rear of the vehicle 1000. The battery device 100 can be used to power the vehicle 1000; for example, the battery device 100 can serve as the operating power source for the vehicle 1000.

[0137] The vehicle 1000 may also include a controller 200 and a motor 300. The controller 200 is used to control the battery device 100 to supply power to the motor 300, for example, for the power needs of the vehicle 1000 during startup, navigation and driving.

[0138] In some embodiments of this application, the battery device 100 can not only serve as the operating power source for the vehicle 1000, but also as the driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0139] Please refer to Figure 2 , Figure 2 This is an exploded view of a battery device 100 provided in some embodiments of this application. The battery device 100 may include a housing 10 and battery cells 20, the housing 10 being used to house the battery cells 20.

[0140] The housing 10 has an enclosed space inside for accommodating the battery cells 20. The housing 10 can have various structures. In some embodiments, the housing 10 may include a first part 11 and a second part 12, which are interlocked. The first part 11 and the second part 12 can have various shapes, such as cuboids or cylinders. The first part 11 can be a hollow structure open on one side, and the second part 12 can also be a hollow structure open on one side. The open side of the second part 12 interlocks with the open side of the first part 11, thus forming a housing 10 with an enclosed space. Alternatively, the first part 11 can be a hollow structure open on one side, and the second part 12 can be a plate-like structure, with the second part 12 interlocking with the open side of the first part 11, thus forming a housing 10 with an accommodating space.

[0141] In the battery device 100, there can be one or more battery cells 20. If there are multiple battery cells 20, they can be connected in series, parallel, or in a mixed configuration. A mixed configuration means that multiple battery cells 20 are connected in both series and parallel. Alternatively, multiple battery cells 20 can be first connected in series, parallel, or in a mixed configuration to form a battery module, and then multiple battery modules can be connected in series, parallel, or in a mixed configuration to form a whole, which is then housed within the housing 10. Another option is that all battery cells 20 can be directly connected in series, parallel, or in a mixed configuration, and then the whole consisting of all battery cells 20 is housed within the housing 10.

[0142] In some embodiments, the battery device 100 may further include a busbar component, through which multiple battery cells 20 can be electrically connected to each other to achieve series, parallel, or mixed connection of the multiple battery cells 20. The busbar component may be a metallic conductor, such as copper, iron, aluminum, stainless steel, aluminum alloy, etc.

[0143] Please refer to Figure 3 , Figure 4 and Figure 5 , Figure 3 This is a schematic diagram of the structure of a battery cell 20 provided in some embodiments of this application. Figure 4 An exploded view of a battery cell 20 provided in some embodiments of this application. Figure 5 This is a schematic diagram of the structure of the electrode assembly 22 provided in some embodiments of this application. Embodiments of this application provide a battery cell 20, which includes a housing 21, an electrode assembly 22, and an elastic layer 226. The electrode assembly 22 is housed within the housing 21. The electrode assembly 22 includes a positive electrode 223, a separator 224, and a negative electrode 225, with the separator 224 disposed between the positive electrode 223 and the negative electrode 225. The elastic layer 226 is disposed between the positive electrode 223 and the negative electrode 225 and is configured to be compressible to provide expansion space for the positive electrode 223 and / or the negative electrode 225.

[0144] Battery cell 20 refers to the smallest unit that makes up battery device 100.

[0145] In some embodiments, the housing 21 may include a housing 211 and an end cap 212, the housing 211 having an opening and the end cap 212 closing the opening of the housing 211. Here, "closing" refers to covering or shutting down, and can be either sealed or unsealed.

[0146] End cap 212 is a component that covers the opening of housing 211 to isolate the internal environment of battery cell 20 from the external environment. The shape of end cap 212 can be adapted to the shape of housing 211 to fit it. Optionally, end cap 212 can be made of a material with certain hardness and strength (such as aluminum alloy), so that end cap 212 is not easily deformed under pressure and impact, giving battery cell 20 higher structural strength and improved reliability. The material of end cap 212 can include, but is not limited to, copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc. Battery cell 20 also includes an insulating member 23, which is disposed inside end cap 212. The insulating member 23 can be used to isolate the electrical connection components inside housing 211 from end cap 212 to reduce the risk of short circuit. For example, insulating member 23 can be plastic, rubber, etc.

[0147] The housing 211 is a component used to cooperate with the end cap 212 to form the internal environment of the battery cell 20. This internal environment can accommodate the electrode assembly 22, electrolyte, and other components. The housing 211 and the end cap 212 can be independent components. An opening can be provided on the housing 211, and the end cap 212 can be used to close the opening to form the internal environment of the battery cell 20. Alternatively, the end cap 212 and the housing 211 can be integrated. Specifically, the end cap 212 and the housing 211 can form a common mating surface before other components are inserted into the housing. When it is necessary to encapsulate the interior of the housing 211, the end cap 212 closes the housing 211. The housing 211 can have various shapes and sizes, such as cuboid, cylindrical, hexagonal prism, etc. Specifically, the shape of the housing 211 can be determined according to the specific shape and size of the electrode assembly 22. The material of the housing 211 can include, but is not limited to, copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc.

[0148] In an embodiment where the housing 211 has an opening at one end, one end cap 212 may be provided. In an embodiment where the housing 211 has openings at opposite ends, two end caps 212 may be provided, with the two end caps 212 respectively closing the two openings of the housing 211. The two end caps 212 and the housing 211 together define the receiving space for accommodating the electrode assembly 22.

[0149] Electrode assembly 22 is the component in the battery cell 20 where electrochemical reactions occur. The housing 211 may contain one or more electrode assemblies 22. The electrode assembly 22 is mainly formed by winding or stacking positive and negative electrode sheets, and typically a separator 224 is provided between the positive and negative electrode sheets. The portions of the positive and negative electrode sheets containing active material constitute the main body 221 of the electrode assembly 22, while the portions of the positive and negative electrode sheets without active material each constitute tabs 222. The positive and negative tabs may be located together at one end of the main body or at opposite ends of the main body 221. During the charging and discharging process of the battery device 100, the positive and negative active materials react with the electrolyte.

[0150] In some embodiments, the battery cell 20 may further include electrode terminals 24, which are disposed on the housing 21 and are used for electrical connection with the tabs 222 of the electrode assembly 22 to input or output electrical energy of the battery cell 20. The electrode terminals 24 may be disposed on the housing 211 of the housing 21 or on the end cap 212 of the housing 21. The electrode terminals 24 and the tabs 222 may be directly connected, for example, by welding. Alternatively, the electrode terminals 24 and the tabs 222 may be indirectly connected, for example, through a current collector. The current collector may be a metallic conductor, such as copper, iron, aluminum, steel, or aluminum alloy.

[0151] As an example, such as Figure 3 and Figure 4 As shown, one end of the housing 211 forms an opening, and there is one end cap 212 in the housing 21, which closes one opening of the housing 211. Two electrode terminals 24 are provided on the end cap 212, which are a positive electrode terminal and a negative electrode terminal, respectively. The end of the electrode assembly 22 facing the end cap 212 has a positive electrode tab and a negative electrode tab. The positive electrode terminal is electrically connected to the positive electrode tab, and the negative electrode terminal is electrically connected to the negative electrode tab.

[0152] The elastic layer 226 is a structure capable of elastic deformation. The elastic layer 226 is disposed between the positive electrode 223 and the negative electrode 225. In some embodiments, the elastic layer 226 may be disposed only between the positive electrode 223 and the separator 224. In other embodiments, the elastic layer 226 may be disposed only between the negative electrode 225 and the separator 224. In still other embodiments, the elastic layer 226 is disposed between both the positive electrode 223 and the separator 224 and between the negative electrode 225 and the separator 224. During the cycling process of the battery cell 20, the positive electrode 223 and / or the negative electrode 225 expand, and the elastic layer 226 can be compressed under the action of the positive electrode 223 and / or the negative electrode 225, thereby providing expansion space for the positive electrode 223 and / or the negative electrode 225.

[0153] An elastic layer 226 is provided between the positive electrode 223 and the negative electrode 225 of the battery cell 20. During the cycling process of the battery cell 20, the positive electrode 223 and / or the negative electrode 225 expand. The elastic layer 226 can be compressed under the action of the positive electrode 223 and / or the negative electrode 225, thereby providing expansion space for the positive electrode 223 and / or the negative electrode 225. This helps to alleviate the phenomenon of stress concentration on the electrode, reduces the risk of electrode breakage, and also reduces the risk of burrs and debris generated at the breakage location piercing the separator 224. This makes it less likely for the positive electrode 223 and the negative electrode 225 to come into contact and short-circuit, thus improving the reliability of the battery device 100.

[0154] Please refer to Figure 3 , Figure 4 and Figure 5 In some embodiments, the positive electrode 223, the separator 224, and the negative electrode 225 are wound together. The electrode assembly 22 includes a flat region 2211 and a bent region 2212 connected to the flat region 2211, and an elastic layer 226 is disposed at least in the bent region 2212.

[0155] The straight region 2211 is the portion of the main body 221 of the electrode assembly 22 that extends along a straight line trajectory.

[0156] The bending region 2212 is the portion of the main body 221 of the electrode assembly 22 that connects to the straight region 2211. The bending region 2212 can extend along an arc trajectory. The main body 221 includes two bending regions 2212, which are respectively connected to the two ends of the straight region 2211.

[0157] The elastic layer 226 can be provided only in the bending area 2212, or the elastic layer 226 can be provided in both the bending area 2212 and the straight area 2211.

[0158] The elastic layer 226 can be provided in only one bending area 2212, or the elastic layer 226 can be provided in two bending areas 2212 respectively.

[0159] The positive electrode 223, separator 224, and negative electrode 225 are wound together, making the electrode assembly 22 a wound electrode assembly. For wound electrode assemblies, the outer electrode sheets of the electrode assembly 22 cannot expand outwards due to the characteristics of the wound structure and the constraint of the outer shell 21 of the battery cell 20. As the inner electrode sheets of the electrode assembly 22 expand outwards, stress concentration becomes more pronounced. By providing an elastic layer 226 at least in the bending region 2212, during the cycling process of the battery cell 20, the positive electrode 223 and / or negative electrode 225 expand, and the elastic layer 226 can be compressed under the action of the positive electrode 223 and / or negative electrode 225, thereby providing expansion space for the positive electrode 223 and / or negative electrode 225, effectively alleviating the stress concentration phenomenon of the electrode sheets and improving the reliability of the battery device 100.

[0160] Please refer to Figure 3 , Figure 4 and Figure 5 In some embodiments, the elastic layer 226 is disposed only in the bending region 2212.

[0161] The elastic layer 226 is only provided in the bending area 2212, and not in the straight area 2211.

[0162] The elastic layer 226 exists only in the bending region 2212 and not in the straight region 2211. On the one hand, the positive electrode 223, the separator 224, and the negative electrode 225 located in the straight region 2211 can be tightly attached together, and the positive electrode 223, the separator 224, and the negative electrode 225 can expand synchronously without wrinkling, further improving the reliability of the battery device 100. On the other hand, it can reduce the space occupied by the elastic layer 226, which is beneficial to improving the energy density of the battery cell 20.

[0163] In other embodiments, the elastic layer 226 is disposed in the bending region 2212 and the straight region 2211.

[0164] "The elastic layer 226 is provided in the bending area 2212 and the straight area 2211", that is, the elastic layer 226 is provided in both the bending area 2212 and the straight area 2211.

[0165] By placing the elastic layer 226 in the bending region 2212 and the straight region 2211, when the positive electrode 223 and / or the negative electrode 225 expands, the elastic layer 226 can be compressed under the action of the positive electrode 223 and / or the negative electrode 225, thereby providing a larger expansion space for the positive electrode 223 and / or the negative electrode 225, effectively alleviating the phenomenon of electrode stress concentration, and improving the reliability of the battery device 100.

[0166] Please refer to Figure 3 , Figure 4 and Figure 5In some embodiments, the positive electrode 223 includes a plurality of first electrode segments 2231 located in the bending region 2212, and the negative electrode 225 includes a plurality of second electrode segments 2251 located in the bending region 2212. An elastic layer 226 is provided between each adjacent first electrode segment 2231 and second electrode segment 2251.

[0167] The first electrode segment 2231 is the portion of the positive electrode 223 located in the bending region 2212. The positive electrode 223 may include two, three, four, or more first electrode segments 2231.

[0168] The second electrode segment 2251 is the portion of the negative electrode 225 located in the bending region 2212. The negative electrode 225 may include two, three, four, or more second electrode segments 2251.

[0169] In the electrode assembly 22, an elastic layer 226 is provided between each adjacent first electrode segment 2231 and second electrode segment 2251 located in the same bending region 2212.

[0170] By providing an elastic layer 226 between each adjacent first electrode segment 2231 and second electrode segment 2251, when the positive electrode 223 and / or negative electrode 225 expands, each elastic layer 226 can be compressed under the action of the positive electrode 223 and / or negative electrode 225, thereby providing a larger expansion space for the positive electrode 223 and / or negative electrode 225, effectively alleviating the phenomenon of electrode stress concentration, and improving the reliability of the battery device 100.

[0171] Please refer to Figure 5 and Figure 6 , Figure 6 This is a schematic diagram of the unfolded structure of the spacer 224 provided in some embodiments of this application. In some embodiments, an elastic layer 226 is disposed on at least one side of the spacer 224.

[0172] The elastic layer 226 may be disposed on only one side of the separator 224 in the thickness direction, or the elastic layer 226 may be disposed on both sides of the separator 224 in the thickness direction. Please refer to... Figure 6 The thickness direction of the separator 224 is the X direction shown in the figure.

[0173] Please refer to Figure 5 and Figure 6 In the embodiment shown in the figure, elastic layers 226 are provided on both sides of the isolation member 224 in the thickness direction.

[0174] Please refer to Figure 7 and Figure 8 ,Figure 7 This is a schematic diagram of the structure of the electrode assembly 22 provided in some other embodiments of this application. Figure 8 This is a schematic diagram of the unfolded structure of the spacer 224 provided in other embodiments of this application. In other embodiments, the elastic layer 226 is disposed only on one side of the spacer 224 in the thickness direction.

[0175] By providing an elastic layer 226 on at least one side of the separator 224, on the one hand, the elastic layer 226 is less likely to adhere to the active material layer, thus having less impact on the active material layer of the positive electrode 223 and / or the negative electrode 225. On the other hand, providing the elastic layer 226 on the separator 224 and coating the current collector with the active material slurry can be manufactured in parallel, which helps to shorten the manufacturing cycle and reduce manufacturing costs.

[0176] Please refer to Figure 7 , Figure 8 and Figure 9 , Figure 9 This is a front view of the spacer 224 after unfolding, as provided in other embodiments of this application. In some embodiments, the spacer 224 includes a plurality of first spacer segments 2243 located in the bending region 2212, and at least one first spacer segment 2243 is provided with an elastic layer 226. The first spacer segment 2243 has a first surface along its thickness direction, and the elastic layer 226 completely covers the first surface.

[0177] The first isolation segment 2243 is the portion of the isolation member 224 located in the bending area 2212. The isolation member 224 may include two, three, four, or more first isolation segments 2243. At least one of the multiple first isolation segments 2243 is provided with an elastic layer 226.

[0178] The first surface is a surface of the first isolation segment 2243 along its thickness direction. The elastic layer 226 is disposed on the first surface and completely covers the first surface.

[0179] Optionally, the spacer 224 includes a first region 2241 and a second region 2242, which are alternately arranged along the length of the spacer 224. In the electrode assembly 22, the first region 2241 is located in the straight region 2211, and the second region 2242 is located in the bending region 2212. Before winding or stacking the electrode assembly 22, a slurry can be continuously applied to the second region 2242 of the spacer 224 to form an elastic layer 226 on the first spacer section 2243.

[0180] The elastic layer 226 completely covers the first surface. During manufacturing, the slurry can be applied to the first surface in a continuous coating manner to form the elastic layer 226, making manufacturing simpler and more convenient.

[0181] Please refer to Figure 10 and Figure 11 , Figure 10 This is a schematic diagram of the structure of the electrode assembly 22 provided in some embodiments of this application. Figure 11 This is a schematic diagram of the unfolded structure of the isolation member 224 provided in some embodiments of this application. In some embodiments, the isolation member 224 includes a plurality of first isolation segments 2243 located in the bending region 2212, and a plurality of elastic layers 226 are provided on at least one side of at least one first isolation segment 2243. The plurality of elastic layers 226 located on the same side of the first isolation segment 2243 are spaced apart along the extending direction of the first isolation segment 2243.

[0182] The first isolation segment 2243 is the portion of the isolation member 224 located in the bending region 2212. The isolation member 224 may include two, three, four, or more first isolation segments 2243. At least one of the multiple first isolation segments 2243 is provided with an elastic layer 226. The first surface is a surface of the first isolation segment 2243 along its thickness direction. The multiple elastic layers 226 are spaced apart on the first surface. The multiple elastic layers 226 may extend along the length direction of the isolation member 224. Please refer to... Figure 11 The length direction of the spacer 224 is the Y direction as shown in the figure.

[0183] Optionally, the spacer 224 includes a first region 2241 and a second region 2242, which are alternately arranged along the length of the spacer 224. In the electrode assembly 22, the first region 2241 is located in the straight region 2211, and the second region 2242 is located in the bent region 2212. Before winding or stacking the electrode assembly 22, a paste can be applied at intervals to the second region 2242 of the spacer 224 to form a plurality of spaced elastic layers 226.

[0184] By providing multiple elastic layers 226 at intervals on the same side of the first isolation section 2243, the gap between two adjacent elastic layers 226 can also serve as an expansion space. This helps to reduce the material consumption of the elastic layers 226 and reduce the manufacturing cost of the electrode assembly 22.

[0185] In some embodiments, the elastic layer 226 is disposed on at least one side of the separator 224.

[0186] By providing an elastic layer 226 on at least one side of the separator 224, on the one hand, the elastic layer 226 is less likely to adhere to the active material layer, thus having less impact on the active material layer of the positive electrode 223 and / or the negative electrode 225. On the other hand, providing the elastic layer 226 on the separator 224 and coating the current collector with the active material slurry can be manufactured in parallel, which helps to shorten the manufacturing cycle and reduce manufacturing costs.

[0187] In some embodiments, the elastic modulus of the elastic layer 226 is A, satisfying: 1 MPa ≤ A ≤ 10 MPa.

[0188] The elastic modulus is an indicator that measures how easily a material undergoes elastic deformation. The larger the value, the greater the stress required to cause a certain elastic deformation in the material, that is, the greater the material stiffness, which means that under a certain stress, the elastic deformation is smaller.

[0189] The elastic modulus of the elastic layer 226 can be: 1 MPa, 10 MPa, 20 MPa, 30 MPa, 40 MPa, 50 MPa, 60 MPa, 70 MPa, 80 MPa, 90 MPa, 100 MPa, etc.

[0190] When A≥1MPa, the elastic modulus of the elastic layer 226 is relatively large. Thus, when the positive electrode 223, the separator 224 and the negative electrode 225 are wound or stacked, the elastic layer 226 can withstand the compressive force generated by the winding or stacking and has elastic deformation margin. During the cycle of the battery cell 20, the positive electrode 223 and / or the negative electrode 225 expand, and the elastic layer 226 can be compressed under the action of the positive electrode 223 and / or the negative electrode 225, thereby providing expansion space for the positive electrode 223 and / or the negative electrode 225, effectively alleviating the phenomenon of electrode stress concentration and improving the reliability of the battery device 100. When A ≤ 100 MPa, the elastic modulus of the elastic layer 226 is not too large, thus facilitating the winding or stacking of the positive electrode 223, the separator 224, and the negative electrode 225. Furthermore, the elastic layer 226 can be compressed under the action of the positive electrode 223 and / or the negative electrode 225, thereby providing expansion space for the positive electrode 223 and / or the negative electrode 225. Therefore, when 1 MPa ≤ A ≤ 10 MPa, it is convenient to wind or stack the positive electrode 223, the separator 224, and the negative electrode 225. When the positive electrode 223 and / or the negative electrode 225 expands, the elastic layer 226 can be compressed under the action of the positive electrode 223 and / or the negative electrode 225, thereby providing expansion space for the positive electrode 223 and / or the negative electrode 225, effectively alleviating the stress concentration phenomenon of the electrode and improving the reliability of the battery device 100.

[0191] In some embodiments, the elastic layer 226 is a coating disposed on at least one of the positive electrode 223, the separator 224, and the negative electrode 225.

[0192] The elastic layer 226 is a coating. The elastic layer 226 may be disposed only on the positive electrode 223. In some embodiments, active material layers are disposed on both sides of the positive electrode 223, then the elastic layer 226 may be a coating disposed on the active material layers of the positive electrode 223. In other embodiments, the positive electrode 223 has an active material layer on only one side, then the elastic layer 226 may be a coating disposed on the active material layer of the positive electrode 223, or it may be a coating disposed on the side of the current collector of the positive electrode 223 facing away from the active material layer. The elastic layer 226 may be disposed only on the separator 224, or it may be disposed on both sides of the separator 224. The elastic layer 226 may be disposed only on the negative electrode 225. In some embodiments, active material layers are disposed on both sides of the negative electrode 225, then the elastic layer 226 may be a coating disposed on the active material layers of the negative electrode 225. In other embodiments, the negative electrode 225 has an active material layer on only one side. In this case, the elastic layer 226 can be a coating layer disposed on the active material layer of the negative electrode 225, or it can be a coating layer disposed on the side of the current collector of the negative electrode 225 facing away from the active material layer. Alternatively, the elastic layer 226 can be disposed on any two of the positive electrode 223, the separator 224, and the negative electrode 225. Or, the elastic layer 226 can be disposed on all three of the positive electrode 223, the separator 224, and the negative electrode 225.

[0193] The elastic layer 226 is a coating. On the one hand, the elastic layer 226 can be manufactured by coating, which is simple and convenient and facilitates mass production. On the other hand, the thickness of the elastic layer 226 is easy to control, which reduces the space occupied while allowing for expansion space, and is beneficial to improving energy density.

[0194] Please refer to this again. Figure 9 In some embodiments, the thickness of the elastic layer 226 is H, which satisfies: 10μm≤H≤100μm.

[0195] H represents the thickness of the elastic layer 226. Measurements can be taken radially along the bending region 2212. Alternatively, the spacer 224 can be unfolded before measurement.

[0196] It should be noted that the thickness of the elastic layer 226 can be varied, that is, the thickness of the elastic layer 226 at different locations can be different, but the minimum thickness of the elastic layer 226 is greater than or equal to 10 μm, and the maximum thickness of the elastic layer 226 is less than or equal to 100 μm.

[0197] The thickness of the elastic layer 226 can be: H = 100μm, 90μm, 80μm, 70μm, 60μm, 50μm, 40μm, 30μm, 20μm, 10μm, etc.

[0198] When H ≥ 10 μm, the elastic layer 226 has a larger thickness, providing greater expansion space when compressed. This helps alleviate stress concentration on the electrode, reduces the risk of electrode breakage, and improves the reliability of the battery device 100. When H ≤ 100 μm, the thickness of the elastic layer 226 is not excessive, thus shortening the ion pathway between the positive electrode 223 and the negative electrode 225. This helps reduce the internal resistance of the battery cell 20 and improves its charge / discharge rate. Therefore, when 10 μm ≤ H ≤ 100 μm, it provides both a larger expansion space for electrode expansion and a shorter ion pathway between the positive electrode 223 and the negative electrode 225.

[0199] Optionally, 30μm≤H≤60μm.

[0200] The thickness of the elastic layer 226 can be: H = 30μm, 35μm, 40μm, 45μm, 50μm, 55μm, 60μm, etc.

[0201] When H ≥ 30 μm, the elastic layer 226 has a larger thickness, providing greater expansion space when compressed. This helps alleviate stress concentration on the electrode, reduces the risk of electrode breakage, and improves the reliability of the battery device 100. When H ≤ 60 μm, the thickness of the elastic layer 226 is not excessive, which helps to shorten the ion pathway between the positive electrode 223 and the negative electrode 225, reducing the internal resistance of the battery cell 20 and increasing its charge / discharge rate. Therefore, when 30 μm ≤ H ≤ 60 μm, it provides both a larger expansion space for electrode expansion and a shorter ion pathway between the positive electrode 223 and the negative electrode 225.

[0202] Please refer to Figure 12 , Figure 12 This is a microscopic schematic diagram of an elastic layer 226 provided in some embodiments of this application. In some embodiments, the elastic layer 226 includes a plurality of elastic units 2261, with channels for metal ions to pass through formed between the plurality of elastic units 2261. The elastic units 2261 contain an electrolyte and are configured to release the electrolyte upon rupture.

[0203] The elastic unit 2261 is a structure capable of elastic deformation. The elastic layer 226 includes a plurality of elastic units 2261, and channels for metal ions to pass through are formed between the plurality of elastic units 2261. In other words, the elastic layer 226 has pores that allow metal ions to pass through.

[0204] Each elastic unit 2261 contains electrolyte. When the elastic unit 2261 breaks, the electrolyte inside the elastic unit 2261 can be released, thereby replenishing the electrolyte between the positive electrode 223 and the negative electrode 225.

[0205] Optionally, the elastic element 2261 is a spherical structure containing an electrolyte.

[0206] During the cycling process of the battery cell 20, the positive electrode 223 and / or the negative electrode 225 expand, which can easily squeeze out the electrolyte between the positive electrode 223 and the negative electrode 225, resulting in poor wetting of the electrode and causing lithium plating. By containing the electrolyte in the elastic unit 2261, when the positive electrode 223 and / or the negative electrode 225 expand, the elastic layer 226 can be compressed under the action of the positive electrode 223 and / or the negative electrode 225. When the pressure on the elastic unit 2261 exceeds a threshold, the elastic unit 2261 ruptures, thereby releasing the electrolyte. The electrolyte can continue to wet the electrode, thereby reducing the risk of lithium plating and improving the reliability of the battery cell 20.

[0207] In some embodiments, the strength of the elastic element 2261 is B, which satisfies: 0.1 MPa ≤ B ≤ 10 MPa.

[0208] B represents the strength of elastic element 2261.

[0209] The strength of the elastic element 2261 can be: B = 0.1 MPa, 0.5 MPa, 1 MPa, 1.5 MPa, 2 MPa, 2.5 MPa, 3 MPa, 3.5 MPa, 4 MPa, 4.5 MPa, 5 MPa, 5.5 MPa, 6 MPa, 6.5 MPa, 7 MPa, 7.5 MPa, 8 MPa, 8.5 MPa, 9 MPa, 9.5 MPa, 10 MPa, etc.

[0210] When B ≥ 0.1 MPa, the elastic unit 2261 has high strength. Therefore, during the winding or stacking of the positive electrode 223, separator 224, and negative electrode 225, the elastic unit 2261 can withstand the compressive force generated by the winding or stacking without breaking, preventing premature consumption of the electrolyte encapsulated in the elastic unit 2261. When B ≤ 10 MPa, the strength of the elastic unit 2261 is not excessively high, allowing it to be crushed under the action of the positive electrode 223 and / or negative electrode 225, releasing the electrolyte. The electrolyte can continue to wet the electrode, reducing the risk of lithium plating and improving the reliability of the battery cell 20. Therefore, when 0.1 MPa ≤ B ≤ 10 MPa, the elastic element can break at a more appropriate time, releasing the electrolyte to wet the electrode.

[0211] Optionally, 0.1 MPa ≤ B ≤ 1 MPa.

[0212] The strength of the elastic element 2261 can be: B = 0.1 MPa, 0.2 MPa, 0.3 MPa, 0.4 MPa, 0.5 MPa, 0.6 MPa, 0.7 MPa, 0.8 MPa, 0.9 MPa, 1 MPa, etc.

[0213] When B ≥ 0.1 MPa, the elastic unit 2261 has high strength. Therefore, during the winding or stacking of the positive electrode 223, separator 224, and negative electrode 225, the elastic unit 2261 can withstand the compressive force generated by the winding or stacking without breaking, preventing premature consumption of the electrolyte encapsulated in the elastic unit 2261. When B ≤ 1 MPa, the strength of the elastic unit 2261 is not too high, allowing it to be crushed under the action of the positive electrode 223 and / or negative electrode 225, releasing the electrolyte. The electrolyte can continue to wet the electrode, reducing the risk of lithium plating and improving the reliability of the battery cell 20. Therefore, when 0.1 MPa ≤ B ≤ 1 MPa, the elastic element is more likely to break at a more appropriate time, releasing the electrolyte to wet the electrode.

[0214] Please refer to Figure 12 In some embodiments, the elastic element 2261 is spherical, and the outer diameter of the elastic element 2261 is D, which satisfies: 5μm≤D≤60μm.

[0215] The elastic element 2261 is a spherical structure or a near-spherical structure.

[0216] D represents the outer diameter of the elastic element 2261. The outer diameter of the elastic element 2261 can be: D = 5μm, 10μm, 15μm, 20μm, 25μm, 30μm, 35μm, 40μm, 45μm, 50μm, 55μm, 60μm, etc.

[0217] When D ≥ 5 μm, the outer diameter of the elastic unit 2261 is relatively large, resulting in a larger gap between multiple elastic units 2261. This facilitates the formation of a larger ion pathway, allowing ions to pass through. When D ≤ 60 μm, the outer diameter of the elastic unit 2261 is not too large, allowing for a smaller elastic layer 226 thickness. This results in a shorter ion pathway between the positive electrode 223 and the negative electrode 225, which helps reduce the internal resistance of the battery cell 20 and improve its charge / discharge rate. Therefore, when 5 μm ≤ D ≤ 60 μm, both a larger and shorter ion pathway can be formed, which is beneficial for reducing the internal resistance of the battery cell 20 and improving its charge / discharge rate.

[0218] Optionally, 10μm≤D≤30μm.

[0219] D represents the outer diameter of the elastic element 2261. The outer diameter of the elastic element 2261 can be: D = 10μm, 12μm, 15μm, 18μm, 20μm, 22μm, 25μm, 28μm, 30μm, etc.

[0220] When D ≥ 10 μm, the outer diameter of the elastic unit 2261 is larger, resulting in a larger gap between multiple elastic units 2261. This is more conducive to forming a larger ion pathway, facilitating ion passage. When D ≤ 30 μm, the outer diameter of the elastic unit 2261 is not too large, allowing for a smaller elastic layer 226 thickness. This results in a shorter ion pathway between the positive electrode 223 and the negative electrode 225, which helps reduce the internal resistance of the battery cell 20 and improve its charge / discharge rate. Therefore, when 10 μm ≤ D ≤ 30 μm, both a larger and shorter ion pathway can be formed, which is beneficial for reducing the internal resistance of the battery cell 20 and improving its charge / discharge rate.

[0221] In some embodiments, the material of the elastic element 2261 includes at least one of polyvinyl alcohol, silicone, polyurethane, and polylactic acid.

[0222] Polyvinyl alcohol, silicone, polyurethane, and polylactic acid are low-cost and elastic, allowing the resulting elastic layer 226 to provide a large expansion space.

[0223] Please refer to Figure 5 This application embodiment also provides an electrode assembly 22, which includes a positive electrode 223, a separator 224, a negative electrode 225, and an elastic layer 226. The separator 224 is disposed between the positive electrode 223 and the negative electrode 225. The elastic layer 226 is disposed between the positive electrode 223 and the negative electrode 225 and is configured to be compressible to provide expansion space for the positive electrode 223 and / or the negative electrode 225.

[0224] An elastic layer 226 is provided between the positive electrode 223 and the negative electrode 225 of the electrode assembly 22. During the cycling process of the battery cell 20, the positive electrode 223 and / or the negative electrode 225 expand. The elastic layer 226 can be compressed under the action of the positive electrode 223 and / or the negative electrode 225, thereby providing expansion space for the positive electrode 223 and / or the negative electrode 225. This helps to alleviate the phenomenon of stress concentration on the electrode, reduces the risk of electrode breakage, and also reduces the risk of burrs and debris generated at the breakage location piercing the separator 224. This makes it less likely for the positive electrode 223 and the negative electrode 225 to come into contact and short-circuit, thus improving the reliability of the battery device 100.

[0225] Please refer to Figure 5In some embodiments, the positive electrode 223, the separator 224, and the negative electrode 225 are wound together. The electrode assembly 22 includes a flat region 2211 and a bent region 2212 connected to the flat region 2211, and an elastic layer 226 is disposed at least in the bent region 2212.

[0226] The straight section 2211 is the portion of the main body 221 of the electrode assembly 22 that extends along a straight line. The bent section 2212 is the portion of the main body 221 of the electrode assembly 22 that connects to the straight section 2211, and the bent section 2212 can extend along an arc. The main body 221 includes two bent sections 2212, which are respectively connected to the two ends of the straight section 2211.

[0227] The elastic layer 226 can be provided only in the bending area 2212, or the elastic layer 226 can be provided in both the bending area 2212 and the straight area 2211. The elastic layer 226 can be provided in only one bending area 2212, or the elastic layer 226 can be provided in two bending areas 2212 respectively.

[0228] The positive electrode 223, separator 224, and negative electrode 225 are wound together, making the electrode assembly 22 a wound electrode assembly. For wound electrode assemblies, the outer electrode sheets of the electrode assembly 22 cannot expand outwards due to the characteristics of the wound structure and the constraint of the outer shell 21 of the battery cell 20. As the inner electrode sheets of the electrode assembly 22 expand outwards, stress concentration becomes more pronounced. By providing an elastic layer 226 at least in the bending region 2212, during the cycling process of the battery cell 20, the positive electrode 223 and / or negative electrode 225 expand, and the elastic layer 226 can be compressed under the action of the positive electrode 223 and / or negative electrode 225, thereby providing expansion space for the positive electrode 223 and / or negative electrode 225, effectively alleviating the stress concentration phenomenon of the electrode sheets and improving the reliability of the battery device 100.

[0229] Please refer to Figure 5 and Figure 12 In some embodiments, the elastic layer 226 includes a plurality of elastic units 2261, with channels for metal ions to pass through formed between the plurality of elastic units 2261, the elastic units 2261 containing an electrolyte, and the elastic units 2261 being configured to release the electrolyte upon rupture.

[0230] The elastic unit 2261 is a structure capable of elastic deformation. The elastic layer 226 includes multiple elastic units 2261, and channels for metal ions to pass through are formed between the multiple elastic units 2261. In other words, the elastic layer 226 has pores that allow metal ions to pass through. Each elastic unit 2261 contains an electrolyte. When the elastic unit 2261 breaks, the electrolyte inside the elastic unit 2261 can be released, thereby replenishing the electrolyte between the positive electrode 223 and the negative electrode 225. Optionally, the elastic unit 2261 is a spherical structure containing an electrolyte.

[0231] During the cycling process of the battery cell 20, the positive electrode 223 and / or the negative electrode 225 expand, which can easily squeeze out the electrolyte between the positive electrode 223 and the negative electrode 225, resulting in poor wetting of the electrode and causing lithium plating. By containing the electrolyte in the elastic unit 2261, when the positive electrode 223 and / or the negative electrode 225 expand, the elastic layer 226 can be compressed under the action of the positive electrode 223 and / or the negative electrode 225. When the pressure on the elastic unit 2261 exceeds a threshold, the elastic unit 2261 ruptures, thereby releasing the electrolyte. The electrolyte can continue to wet the electrode, thereby reducing the risk of lithium plating and improving the reliability of the battery cell 20.

[0232] Please refer to Figure 13 , Figure 13 This is a schematic block diagram illustrating an electrode assembly manufacturing method 30 provided in some embodiments of this application. Embodiments of this application also provide an electrode assembly manufacturing method 30, which includes:

[0233] Step S100: Provide a positive electrode 223, a separator 224, and a negative electrode 225;

[0234] Step S200: An elastic layer 226 is provided on at least one of the positive electrode 223, the separator 224 and the negative electrode 225;

[0235] Step S300: Wind or stack the positive electrode 223, the separator 224 and the negative electrode 225 to form an electrode assembly 22, wherein an elastic layer 226 is disposed between the positive electrode 223 and the negative electrode 225, and the elastic layer 226 is configured to be compressible to provide expansion space for the positive electrode 223 and / or the negative electrode 225.

[0236] In step S200, the elastic layer 226 may be disposed only on the positive electrode 223. In some embodiments, active material layers are disposed on both sides of the positive electrode 223, and the elastic layer 226 may be disposed on the active material layers of the positive electrode 223. In other embodiments, the positive electrode 223 has an active material layer on only one side, and the elastic layer 226 may be disposed on the active material layer of the positive electrode 223, or it may be disposed on the side of the current collector of the positive electrode 223 facing away from the active material layer. The elastic layer 226 may be disposed only on the separator 224, either on one side of the separator 224 or on both sides of the separator 224. The elastic layer 226 may be disposed only on the negative electrode 225. In some embodiments, active material layers are disposed on both sides of the negative electrode 225, and the elastic layer 226 may be disposed on the active material layers of the negative electrode 225. In some embodiments, the negative electrode 225 has an active material layer on only one side. In this case, the elastic layer 226 can be disposed on the active material layer of the negative electrode 225, or on the side of the current collector of the negative electrode 225 facing away from the active material layer. Alternatively, the elastic layer 226 can be disposed on any two of the positive electrode 223, the separator 224, and the negative electrode 225. Or, the elastic layer 226 can be disposed on all three of the positive electrode 223, the separator 224, and the negative electrode 225.

[0237] In step S300, the positive electrode 223, the separator 224, and the negative electrode 225 can be wound to form an electrode assembly 22, in which case the electrode assembly 22 is a wound electrode assembly. Alternatively, the positive electrode 223, the separator 224, and the negative electrode 225 can be stacked to form the electrode assembly 22, in which case the electrode assembly 22 is a stacked electrode assembly.

[0238] An elastic layer 226 is provided between the positive electrode 223 and the negative electrode 225 of the electrode assembly 22 manufactured by the electrode assembly manufacturing method 30. During the cycle of the battery cell 20, the positive electrode 223 and / or the negative electrode 225 expand. The elastic layer 226 can be compressed under the action of the positive electrode 223 and / or the negative electrode 225, thereby providing expansion space for the positive electrode 223 and / or the negative electrode 225. This helps to alleviate the phenomenon of stress concentration on the electrode, reduces the risk of electrode breakage, and also reduces the risk of burrs and debris generated at the breakage location piercing the separator 224. This makes it less likely for the positive electrode 223 and the negative electrode 225 to come into contact and short-circuit, thus improving the reliability of the battery device 100.

[0239] Please refer to Figure 14 , Figure 14 This is a schematic block diagram of an electrode assembly manufacturing method 30 provided for other embodiments of this application. In other embodiments, step S200 includes:

[0240] Step S210: Apply a paste to at least one of the positive electrode 223, the separator 224 and the negative electrode 225 to form an elastic layer 226.

[0241] In step S210, a slurry may be coated onto the positive electrode 223. In some embodiments, active material layers are provided on both sides of the positive electrode 223, in which case the slurry may be coated onto the active material layers of the positive electrode 223 to form an elastic layer 226. In other embodiments, the positive electrode 223 has an active material layer on only one side, in which case the slurry may be coated onto the active material layer of the positive electrode 223, or the slurry may be coated onto the side of the current collector of the positive electrode 223 facing away from the active material layer to form an elastic layer 226. Alternatively, the slurry may be coated onto one or both sides of the separator 224 to form an elastic layer 226. The slurry may also be coated onto the negative electrode 225. In some embodiments, active material layers are provided on both sides of the negative electrode 225, in which case the slurry may be coated onto the active material layers of the negative electrode 225 to form an elastic layer 226. In other embodiments, the negative electrode 225 has an active material layer on only one side. In this case, the slurry can be coated onto the active material layer of the negative electrode 225, or the slurry can be coated onto the side of the current collector of the negative electrode 225 facing away from the active material layer, to form the elastic layer 226. Alternatively, the slurry can be coated onto any two of the positive electrode 223, the separator 224, and the negative electrode 225 to form the elastic layer 226. Or, the slurry can be coated onto all three of the positive electrode 223, the separator 224, and the negative electrode 225 to form the elastic layer 226.

[0242] An elastic layer 226 is formed on at least one of the positive electrode 223, the separator 224, and the negative electrode 225 by coating a slurry onto them. This method is simple and convenient to manufacture, facilitating mass production. Furthermore, the thickness of the elastic layer 226 is easy to control, reducing space occupation while allowing for expansion, which is beneficial for improving energy density.

[0243] Please refer to Figure 15 , Figure 15 This is a schematic block diagram of an electrode assembly manufacturing method 30 provided for further embodiments of this application. In some of these embodiments, step S210 includes:

[0244] Step S211: Apply slurry to at least one side of the spacer 224 to form an elastic layer 226.

[0245] The slurry can be applied to one side of the isolation member 224 in the thickness direction to form an elastic layer 226 on one side of the isolation member 224 in the thickness direction, or the slurry can be applied to both sides of the isolation member 224 in the thickness direction to form an elastic layer 226 on both sides of the isolation member 224 in the thickness direction.

[0246] In some embodiments, please refer to Figure 6 , Figure 6 This is the product after step S211. Figure 6 In the embodiment shown, the slurry is coated on both sides of the separator 224 in the thickness direction to form an elastic layer 226 on both sides of the separator 224 in the thickness direction.

[0247] In other embodiments, please refer to Figure 8 , Figure 8 This is the product after step S211. Figure 8 In the embodiment shown, the slurry is applied only to one side of the isolation member 224 in the thickness direction to form an elastic layer 226 on one side of the isolation member 224 in the thickness direction.

[0248] By coating at least one side of the separator 224 with a slurry to form an elastic layer 226, on the one hand, the elastic layer 226 does not easily adhere to the active material layer, thus having less impact on the active material layer of the positive electrode 223 and / or the negative electrode 225. On the other hand, the provision of the elastic layer 226 on the separator 224 and the coating of the active material slurry on the current collector can be manufactured in parallel, which helps to shorten the manufacturing cycle and reduce manufacturing costs.

[0249] Please refer to Figure 16 , Figure 16 This is a schematic block diagram of an electrode assembly manufacturing method 30 provided for further embodiments of this application. In further embodiments, step S300 includes:

[0250] Step S310: Wind the positive electrode 223, the separator 224 and the negative electrode 225 to form an electrode assembly 22. The electrode assembly 22 includes a flat region 2211 and a bent region 2212 connected to the flat region 2211. An elastic layer 226 is disposed at least in the bent region 2212.

[0251] A positive electrode 223, a separator 224, and a negative electrode 225 are wound to form an electrode assembly 22, which is a wound electrode assembly. A straight section 2211 is the portion of the main body 221 of the electrode assembly 22 that extends along a straight line. A bending section 2212 is the portion of the main body 221 of the electrode assembly 22 that connects to the straight section 2211; the bending section 2212 may extend along an arc. The main body 221 includes two bending sections 2212, which are respectively connected to the two ends of the straight section 2211. An elastic layer 226 may be provided only in the bending section 2212, or it may be provided simultaneously in both the bending section 2212 and the straight section 2211. The elastic layer 226 may be provided only in one bending section 2212, or it may be provided in both bending sections 2212.

[0252] The positive electrode 223, separator 224, and negative electrode 225 are wound together, making the electrode assembly 22 a wound electrode assembly. For wound electrode assemblies, the outer electrode sheets of the electrode assembly 22 cannot expand outwards due to the characteristics of the wound structure and the constraint of the outer shell 21 of the battery cell 20. As the inner electrode sheets of the electrode assembly 22 expand outwards, stress concentration becomes more pronounced. By providing an elastic layer 226 at least in the bending region 2212, during the cycling process of the battery cell 20, the positive electrode 223 and / or negative electrode 225 expand, and the elastic layer 226 can be compressed under the action of the positive electrode 223 and / or negative electrode 225, thereby providing expansion space for the positive electrode 223 and / or negative electrode 225, effectively alleviating the stress concentration phenomenon of the electrode sheets and improving the reliability of the battery device 100.

[0253] Please refer to Figure 17 , Figure 17 This is a schematic block diagram of an electrode assembly manufacturing method 30 provided in some embodiments of this application. In some embodiments, the spacer 224 includes a first region 2241 and a second region 2242, which are alternately arranged along the length of the spacer 224. In the electrode assembly 22, the first region 2241 is located in the straight region 2211, and the second region 2242 is located in the bent region 2212. Step S200 includes:

[0254] Step S220: Continuously apply slurry to at least one side of the second region 2242 to form an elastic layer 226.

[0255] According to the design, a first region 2241 and a second region 2242 can be divided on the separator 224. The first region 2241 is located in the straight section 2211 of the winding structure 22a, and the second region 2242 is located in the bending section 2212 of the winding structure 22a. The first region 2241 and the second region 2242 are alternately arranged along the length of the separator 224. In other words, the second region 2242 forms the first separator segment 2243 after winding.

[0256] In step S220, the slurry can be continuously applied to one side of the second region 2242 or to both sides of the second region 2242.

[0257] The slurry is applied to at least one side of the second region 2242 using a continuous coating method, which makes the manufacturing process simpler and more convenient.

[0258] Please refer to Figure 18 , Figure 18This is a schematic block diagram of an electrode assembly manufacturing method 30 provided for further embodiments of this application. In some of these embodiments, the spacer 224 includes a first region 2241 and a second region 2242. Along the length of the spacer 224, the first region 2241 and the second region 2242 are alternately arranged. In the electrode assembly 22, the first region 2241 is located in the straight region 2211, and the second region 2242 is located in the bent region 2212. Step S200 includes:

[0259] Step S230: Along the length of the spacer 224, a slurry is applied at intervals to at least one side of the second region 2242 to form a plurality of spaced elastic layers 226.

[0260] In step S230, the slurry can be applied at intervals on one side of the second region 2242 or at intervals on both sides of the second region 2242.

[0261] Please refer to Figure 11 , Figure 11 This is the product after step S230. Figure 11 In the illustrated embodiment, elastic layers 226 are formed on both sides of the second region 2242, and multiple elastic layers 226 are spaced apart within one second region 2242 on each side. Correspondingly, in step S230, a slurry is applied at intervals to both sides of the second region 2242 to form multiple spaced elastic layers 226.

[0262] Applying slurry to at least one side of the second region 2242 using an intermittent coating method helps reduce slurry consumption, lower slurry raw material costs, and reduce the manufacturing cost of the electrode assembly 22.

[0263] This application embodiment also provides a battery device 100, which includes the aforementioned battery cell 20.

[0264] This application embodiment also provides an electrical device, which includes the aforementioned battery cell 20, and the battery cell 20 is used to provide electrical energy to the electrical device.

[0265] According to some embodiments of this application, please refer to Figures 3 to 12 .

[0266] This application provides a battery cell 20, which includes a housing 21, an electrode assembly 22, and an elastic layer 226. The electrode assembly 22 is housed within the housing 21. The electrode assembly 22 includes a positive electrode 223, a separator 224, and a negative electrode 225, with the separator 224 disposed between the positive electrode 223 and the negative electrode 225. The elastic layer 226 is disposed between the positive electrode 223 and the negative electrode 225 and is configured to be compressible to provide expansion space for the positive electrode 223 and / or the negative electrode 225. An elastic layer 226 is provided between the positive electrode 223 and the negative electrode 225 of the battery cell 20. During the cycling process of the battery cell 20, the positive electrode 223 and / or the negative electrode 225 expand. The elastic layer 226 can be compressed under the action of the positive electrode 223 and / or the negative electrode 225, thereby providing expansion space for the positive electrode 223 and / or the negative electrode 225. This helps to alleviate the phenomenon of stress concentration on the electrode, reduces the risk of electrode breakage, and also reduces the risk of burrs and debris generated at the breakage location piercing the separator 224. This makes it less likely for the positive electrode 223 and the negative electrode 225 to come into contact and short-circuit, thus improving the reliability of the battery device 100.

[0267] The positive electrode 223, separator 224, and negative electrode 225 are wound together. The electrode assembly 22 includes a flat region 2211 and a bent region 2212 connected to the flat region 2211, and an elastic layer 226 is disposed at least in the bent region 2212. Since the positive electrode 223, separator 224, and negative electrode 225 are wound together, the electrode assembly 22 is a wound electrode assembly. For a wound electrode assembly, the outer electrode of the electrode assembly 22 cannot expand outward due to the characteristics of the wound structure and the constraint of the outer shell 21 of the battery cell 20. As the inner electrode of the electrode assembly 22 expands outward, the stress concentration becomes more pronounced. By providing at least the elastic layer 226 in the bending region 2212, during the cycling process of the battery cell 20, the positive electrode 223 and / or the negative electrode 225 expand, and the elastic layer 226 can be compressed under the action of the positive electrode 223 and / or the negative electrode 225, thereby providing expansion space for the positive electrode 223 and / or the negative electrode 225, effectively alleviating the phenomenon of electrode stress concentration, and improving the reliability of the battery device 100.

[0268] The elastic layer 226 is only disposed in the bending region 2212. Since the elastic layer 226 exists only in the bending region 2212 and not in the straight region 2211, on the one hand, the positive electrode 223, the separator 224, and the negative electrode 225 located in the straight region 2211 can adhere tightly together, and the positive electrode 223, the separator 224, and the negative electrode 225 can expand synchronously without wrinkling, further improving the reliability of the battery device 100. On the other hand, it reduces the space occupied by the elastic layer 226, which is beneficial to improving the energy density of the battery cell 20.

[0269] The positive electrode 223 includes multiple first electrode segments 2231 located in the bending region 2212, and the negative electrode 225 includes multiple second electrode segments 2251 located in the bending region 2212. An elastic layer 226 is provided between each adjacent first electrode segment 2231 and second electrode segment 2251. By providing an elastic layer 226 between each adjacent first electrode segment 2231 and second electrode segment 2251, when the positive electrode 223 and / or the negative electrode 225 expands, each elastic layer 226 can be compressed under the action of the positive electrode 223 and / or the negative electrode 225, thereby providing a larger expansion space for the positive electrode 223 and / or the negative electrode 225, effectively alleviating the phenomenon of electrode stress concentration, and improving the reliability of the battery device 100.

[0270] The elastic layer 226 includes multiple elastic units 2261, forming channels between them for metal ions to pass through. Each elastic unit 2261 contains an electrolyte and is configured to release the electrolyte upon rupture. During battery cell 20 cycling, the positive electrode 223 and / or negative electrode 225 expand, easily squeezing out the electrolyte between them, resulting in poor electrode wetting and lithium plating. By containing the electrolyte within the elastic units 2261, when the positive electrode 223 and / or negative electrode 225 expand, the elastic layer 226 can be compressed under the action of the positive electrode 223 and / or negative electrode 225. When the pressure on the elastic unit 2261 exceeds a threshold, the elastic unit 2261 ruptures, releasing the electrolyte. The electrolyte can then continue to wet the electrode, reducing the risk of lithium plating and improving the reliability of the battery cell 20.

[0271] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A battery cell, characterized by, The application relates to a battery electrode assembly. The battery electrode assembly comprises: a shell; an electrode assembly accommodated in the shell, the electrode assembly comprising a positive electrode sheet, a separator and a negative electrode sheet, the separator being arranged between the positive electrode sheet and the negative electrode sheet; 2. The battery cell of claim 1, wherein, an elastic layer arranged between the positive electrode sheet and the negative electrode sheet, the elastic layer being configured to be compressed to provide expansion space for the positive electrode sheet and / or the negative electrode sheet. The positive electrode sheet, the separator and the negative electrode sheet are arranged in a winding manner.

3. The battery cell of claim 2, wherein, The electrode assembly comprises a flat area and a bending area connected with the flat area, and the elastic layer is arranged at least in the bending area.

4. The battery cell of claim 2, wherein, The elastic layer is arranged only in the bending area.

5. The battery cell of claim 2, wherein, The elastic layer is arranged in the bending area and the flat area. The positive electrode sheet comprises a plurality of first electrode segments in the bending area, and the negative electrode sheet comprises a plurality of second electrode segments in the bending area.

6. The battery cell of claim 2, wherein, The elastic layer is arranged between each adjacent first electrode segment and second electrode segment.

7. The battery cell of claim 6, wherein the cathode comprises a lithium metal oxide. The elastic layer is arranged on at least one side of the separator.

8. The battery cell of claim 6, wherein, The separator comprises a plurality of first separator segments in the bending area, at least one of the first separator segments is provided with the elastic layer, the first separator segment has a first surface along the thickness direction of the first separator segment, and the elastic layer completely covers the first surface.

9. The battery cell of claim 1, wherein, The separator comprises a plurality of first separator segments in the bending area, at least one side of at least one of the first separator segments is provided with a plurality of elastic layers, and the plurality of elastic layers arranged on the same side of the first separator segment are arranged in a spacing manner along the extension direction of the first separator segment.

10. The battery cell of claim 1, wherein, The elastic layer is arranged on at least one side of the separator.

11. The battery cell of claim 1, wherein, The elastic modulus of the elastic layer is A, and 1 Mpa <= A <= 10 Mpa.

12. The battery cell of claim 1, wherein, The elastic layer is a coating layer arranged on at least one of the positive electrode sheet, the separator and the negative electrode sheet.

13. The battery cell of claim 12, wherein the cathode comprises a lithium metal oxide. The thickness of the elastic layer is H, and 10 mu m <= H <= 100 mu m.

14. The battery cell of any one of claims 1-13, wherein, 30 mu m <= H <= 60 mu m.

15. The battery cell of claim 14, wherein the cathode comprises a lithium metal oxide. The elastic layer comprises a plurality of elastic units, a channel for metal ions to pass through is formed between the plurality of elastic units, the elastic unit contains electrolyte, and the elastic unit is configured to release the electrolyte when broken.

16. The battery cell of claim 15, wherein, The strength of the elastic unit is B, and 0.1 Mpa <= B <= 10 Mpa.

17. The battery cell of claim 14, wherein the cathode comprises a lithium metal oxide. 0.1 Mpa <= B <= 1 Mpa.

18. The battery cell of claim 17, wherein, The elastic unit is spherical, the outer diameter of the elastic unit is D, and 5 mu m <= D <= 60 mu m.

19. The battery cell of claim 14, wherein, 10 mu m <= D <= 30 mu m.

20. An electrode assembly, characterized by, The material of the elastic unit comprises at least one of polyvinyl alcohol, silica gel, polyurethane and polylactic acid.

21. The electrode assembly of claim 20, wherein, The battery electrode assembly comprises a positive electrode sheet, a separator, a negative electrode sheet and an elastic layer, the separator is arranged between the positive electrode sheet and the negative electrode sheet, the elastic layer is arranged between the positive electrode sheet and the negative electrode sheet, and the elastic layer is configured to be compressed to provide expansion space for the positive electrode sheet and / or the negative electrode sheet. The positive electrode sheet, the separator and the negative electrode sheet are arranged in a winding manner. The electrode assembly comprises a flat area and a bending area connected with the flat area, and the elastic layer is arranged at least in the bending area.

22. The electrode assembly of claim 20 or 21, wherein, The elastic layer comprises a plurality of elastic units, channels for metal ions to pass through are formed between the plurality of elastic units, the elastic units contain electrolyte, and the elastic units are configured to release the electrolyte when ruptured.

23. A method for manufacturing an electrode assembly, characterized by comprising: The method comprises: Step S100: providing a positive electrode sheet, a separator, and a negative electrode sheet; Step S200: providing an elastic layer on at least one of the positive electrode sheet, the separator, and the negative electrode sheet; Step S300: winding or stacking the positive electrode sheet, the separator, and the negative electrode sheet to form the electrode assembly, wherein the elastic layer is arranged between the positive electrode sheet and the negative electrode sheet, and the elastic layer is configured to be compressed to provide an expansion space for the positive electrode sheet and / or the negative electrode sheet.

24. The method of claim 23, wherein the step of forming the electrode assembly is performed by a method comprising: The step S200 comprises: ​ Step S210: coating a slurry on at least one of the positive electrode sheet, the separator, and the negative electrode sheet to form the elastic layer.

25. The method of claim 24, wherein the step of forming the electrode assembly is performed by a method comprising: The step S210 comprises: ​ Step S211: coating the slurry on at least one side of the separator to form the elastic layer.

26. The method for manufacturing an electrode assembly according to any one of claims 23-25, characterized in that, The step S300 comprises: Step S310: winding the positive electrode sheet, the separator, and the negative electrode sheet to form an electrode assembly, the electrode assembly comprising a flat area and a bending area connected to the flat area, and the elastic layer is arranged at least in the bending area.

27. The method for manufacturing an electrode assembly according to claim 26, characterized in that, The separator comprises a first area and a second area, the first area and the second area are arranged alternately along the length direction of the separator, in the electrode assembly, the first area is located in the flat area, and the second area is located in the bending area; The step S200 comprises: Step S220: continuously coating a slurry on at least one side of the second area to form the elastic layer.

28. The method of claim 26, wherein the step of forming the electrode assembly is performed by a method comprising: The separator comprises a first area and a second area, the first area and the second area are arranged alternately along the length direction of the separator, in the electrode assembly, the first area is located in the flat area, and the second area is located in the bending area; ​ The step S200 comprises: Step S230: coating a slurry on at least one side of the second area at intervals along the length direction of the separator to form a plurality of elastic layers arranged at intervals.

29. A battery device, characterized by The battery cell according to any one of claims 1-19.

30. An electrical device, comprising: The battery cell according to any one of claims 1-19 is used to provide electric energy for the electric device.

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