Wound electrode assembly, battery cell, battery device, and electric device

Abstract

The utility model discloses a winding type electrode assembly, a battery monomer, a battery device and a power utilization device, the winding type electrode assembly comprises a positive plate, a negative plate and a diaphragm, the diaphragm is arranged between the positive plate and the negative plate, wrinkles are formed on the diaphragm, and the wrinkles extend along the winding direction of the diaphragm. By arranging the diaphragm between the positive plate and the negative plate and forming the wrinkles on the diaphragm, the thickness of the diaphragm in the region corresponding to the wrinkles can be increased, so that a gap between the positive plate and the negative plate can be increased, and the gap can reserve a certain buffer space between the positive plate and the negative plate; the expansion force is relieved through the buffer space between the pole pieces, the extrusion force between the pole pieces is relieved, the possibility that the pole pieces are broken due to expansion and contraction in the circulating charging and discharging process of the winding type electrode assembly can be reduced, particularly, the expansion force borne by the pole pieces on the outer ring can be reduced, and therefore the possibility that the pole pieces on the outer ring are broken is reduced.

Description

Technical Field

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

[0002] In related technologies, winding is a common method for assembling battery electrodes. This involves fixing the positive electrode, negative electrode, and separator onto a roller, and then winding them into an electrode assembly as the roller rotates. However, during the cyclic charging and discharging of a wound electrode assembly, the electrodes expand and contract, causing them to compress against each other. Under high compressive forces, this can lead to electrode breakage, especially since the expansion forces concentrate on the outer ring of the electrode assembly, making the outer electrodes more prone to breakage. Therefore, reducing the likelihood of breakage of the outer electrodes in a wound electrode assembly has become a pressing technical problem. Utility Model Content

[0003] In view of the above problems, this application provides a wound electrode assembly, a battery cell, a battery device, and an electrical device. The wound electrode assembly can reduce the possibility of the electrode sheet breaking due to expansion and contraction during the cyclic charging and discharging of the wound electrode assembly.

[0004] In a first aspect, this application provides a wound electrode assembly, which includes: a positive electrode sheet; a negative electrode sheet; and a separator, wherein the separator is disposed between the positive electrode sheet and the negative electrode sheet, and the separator has folds formed on it, the folds extending along the winding direction of the separator.

[0005] In the above technical solution, by providing a separator between the positive and negative electrodes and forming pleats on the separator, the surface of the separator in the pleated area protrudes above the surface of other areas of the separator, thereby increasing the thickness of the separator in the pleated area. This increases the gap between the positive and negative electrodes, providing a buffer space. During charging and discharging, the buffer space between the electrodes alleviates the expansion force and reduces the squeezing force between the electrodes, reducing the possibility of electrode breakage due to expansion and contraction during the cyclic charging and discharging of the wound electrode assembly. In particular, it reduces the expansion force borne by the outer electrode, thereby reducing the possibility of outer electrode breakage and extending the service life of the wound electrode assembly. Furthermore, the gap between the positive and negative electrodes facilitates electrolyte diffusion and allows the electrolyte to better penetrate into the interior of the wound electrode assembly, enabling at least a portion of the positive and negative electrodes to make more sufficient contact with the electrolyte, which is beneficial to improving the overall performance of the wound electrode assembly.

[0006] In some embodiments, the folds are formed as a multi-layered folded structure.

[0007] In the above technical solution, the folds of the multi-layer folded structure can make the separator film thicker, thereby making the gap between the positive electrode and the negative electrode larger, so as to more effectively reduce the extrusion pressure between the electrodes, thereby reducing the possibility of the electrodes breaking due to expansion and contraction during the cyclic charging and discharging of the wound electrode assembly. In particular, it can reduce the expansion force borne by the outer electrode, thereby effectively reducing the possibility of the outer electrode breaking.

[0008] In some embodiments, at least a portion of the folds are formed as a three-layer folded structure.

[0009] In the above technical solution, at least some of the folds are formed into a three-layer folded structure, which can make the thickness of this separator membrane larger, so that the gap between the electrodes is larger. This can effectively reduce the extrusion pressure between the electrodes, thereby reducing the possibility of the electrodes breaking due to expansion and contraction during the cyclic charging and discharging of the wound electrode assembly.

[0010] In some embodiments, there are multiple folds, and at least some of the folds are spaced apart along the winding axis of the diaphragm.

[0011] In the above technical solution, by arranging multiple folds, at least some of which are spaced along the winding axis of the separator, multiple gaps can be formed between the positive and negative electrode sheets along the winding axis of the separator. This allows multiple spaced buffer spaces to be formed between the positive and negative electrode sheets along the winding axis of the separator. These spaced buffer spaces can more evenly reduce the compressive force between the electrodes, thereby effectively reducing the possibility of the positive or negative electrode sheets breaking due to expansion and contraction during the cyclic charging and discharging of the wound electrode assembly.

[0012] In some embodiments, at least some of the folds are evenly spaced along the winding axis of the diaphragm.

[0013] In the above technical solution, by arranging at least some of the folds evenly along the winding axis of the separator, the gap between the positive electrode and the negative electrode can be evenly spaced along the winding axis of the separator. This allows the expansion force borne by the positive or negative electrode to be more evenly distributed through these evenly distributed gaps, thereby significantly reducing the risk of breakage of the positive or negative electrode due to the concentration of expansion force. This effectively improves the overall performance of the wound electrode assembly and extends the overall service life of the wound electrode assembly.

[0014] In some embodiments, the width of the folds ranges from 0.1 mm to 5 mm.

[0015] In the above technical solution, by using a fold width w1 ranging from 0.1mm to 5mm, the gap width formed between the positive and negative electrode plates after at least part of the membrane deformation and the structural strength of the membrane itself can be better balanced. This effectively reduces the possibility of the positive or negative electrode plates breaking due to expansion and contraction, while also making the overall size of the wound electrode assembly smaller.

[0016] In some embodiments, the width of the folds ranges from 0.15 mm to 2 mm.

[0017] In the above technical solution, by using a pleat width w1 ranging from 0.15mm to 2mm, the gap width formed between the positive and negative electrode plates and the overall size of the wound electrode assembly can be better balanced after at least part of the diaphragm is deformed.

[0018] In some embodiments, the diaphragm includes planar portions and bent portions arranged alternately along the winding direction of the diaphragm, wherein the planar portions extend in a straight line and the bent portions extend in an arc, and the bent portions are provided with the folds.

[0019] In the above technical solution, by providing pleats in the bending part, the gap between the positive electrode and the negative electrode corresponding to the bending part can be increased, so as to buffer the bending force and expansion force at the electrode corresponding to the bending part, thereby effectively reducing the possibility of the positive electrode or the negative electrode breaking due to excessive concentration of expansion force or bending force, which is beneficial to extending the service life of the wound electrode assembly.

[0020] In some embodiments, the planar portion is provided with the folds.

[0021] In the above technical solution, by providing pleats in the flat part, the gap between the corresponding positive electrode and negative electrode can be increased. This gap can alleviate the expansion force between the positive electrode and negative electrode during charging and discharging, reduce the squeezing force between the electrodes, thereby effectively reducing the possibility of breakage of the positive electrode or negative electrode, which is beneficial to extending the service life of the wound electrode assembly.

[0022] In some embodiments, at least some of the folds on the planar portion and at least some of the folds on the bent portion are connected in the winding direction of the diaphragm to form continuous folds.

[0023] In the above technical solution, at least some of the folds on the flat part and at least some of the folds on the bent part are connected in the winding direction of the diaphragm to form continuous folds. This makes the processing and manufacturing of the diaphragm more convenient. The continuous folds can also enhance the connection strength between the flat part and the bent part. The continuous folds can also guide the expansion force of the positive or negative electrode plate on the diaphragm to be transmitted and dispersed more smoothly between the flat part and the bent part, avoiding the expansion force from being too concentrated in one place, thereby reducing the possibility of the positive or negative electrode plate breaking due to the concentration of expansion force.

[0024] In some embodiments, the arrangement density of the folds on the bent portion is greater than or equal to the arrangement density of the folds on the planar portion.

[0025] In the above technical solution, the arrangement density of the pleats on the bending section can be equal to that on the flat section, which makes the diaphragm easier to manufacture and the processing technology simpler. Because the arrangement density of the pleats on the bending section is greater than that on the flat section, the expansion force and bending force of the electrode corresponding to the bending section can be more effectively dispersed, thereby effectively reducing the possibility of breakage of the positive or negative electrode corresponding to the bending section, and thus improving the overall service life of the wound electrode assembly.

[0026] In some embodiments, the ratio of the extension length of the pleats in the winding direction of the diaphragm to the winding length of the diaphragm is greater than 0.8.

[0027] In the above technical solution, by making the ratio of the extension length of the pleats in the winding direction of the separator to the winding length of the separator greater than 0.8, the extension length of the pleats in the winding direction of the separator can be longer, so that the pleats can more comprehensively and effectively buffer the expansion force between the positive electrode and the negative electrode, effectively reducing the possibility of breakage of the positive electrode or the negative electrode.

[0028] In some embodiments, the thickness of the diaphragm ranges from 3 μm to 30 μm.

[0029] In the above technical solution, the thickness of the diaphragm is in the range of 3μm to 30μm, which gives the diaphragm a certain structural strength and also allows the diaphragm to form wrinkles well.

[0030] In some embodiments, the thickness of the diaphragm ranges from 5 μm to 15 μm.

[0031] In the above technical solution, by using a diaphragm thickness range of 5μm to 15μm, the structural strength of the diaphragm and the possibility of the diaphragm forming wrinkles in a predetermined area can be well balanced. While the diaphragm has high structural strength, it makes it easier for the diaphragm to form wrinkles in the predetermined area.

[0032] Secondly, this application provides a battery cell, including: a housing; and a wound electrode assembly according to a first aspect of this application, wherein the wound electrode assembly is disposed within the housing.

[0033] In the above technical solution, by setting the above-mentioned wound electrode assembly, the battery cell can have a longer service life and better performance.

[0034] Thirdly, this application provides a battery device, including: a battery cell according to the second aspect of this application.

[0035] In the above technical solution, by incorporating the aforementioned battery cells, the battery device can have a longer service life and better performance.

[0036] Fourthly, this application provides an electrical device, including: a battery device according to the third aspect of this application.

[0037] In the above technical solution, by incorporating the aforementioned battery device, it is beneficial to improve the overall performance of the electrical device.

[0038] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0039] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0040] Figure 1 This is a schematic diagram of a wound electrode assembly according to some embodiments of this application;

[0041] Figure 2 yes Figure 1 A schematic diagram of the diaphragm in the wound electrode assembly;

[0042] Figure 3 This is a schematic diagram of the diaphragm of a wound electrode assembly according to some embodiments of this application;

[0043] Figure 4 This is a schematic diagram of a battery cell according to some embodiments of this application;

[0044] Figure 5 This is a simplified schematic diagram of a battery device according to some embodiments of this application;

[0045] Figure 6 This is a simplified schematic diagram of an electrical device according to some embodiments of this application.

[0046] Figure label:

[0047] 1000. Electrical appliances;

[0048] 100. Battery device;

[0049] 10. Battery cell; 101. Casing;

[0050] 20. Winded electrode assembly; 201. Positive electrode sheet; 2011. First planar portion; 2012. First bent portion; 202. Negative electrode sheet; 2021. Second planar portion; 2022. Second bent portion; 203. Separator; 2031. Planar portion; 2032. Bent portion; 2033. Pleats;

[0051] 200. Vehicle body. Detailed Implementation

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] In this application, "multiple" means two or more (including two).

[0059] In the embodiments of this application, unless otherwise specified, all implementation methods and optional implementation methods of this application can be combined with each other to form new technical solutions.

[0060] In the embodiments of this application, unless otherwise specified, all technical features and optional technical features of this application can be combined with each other to form new technical solutions.

[0061] In embodiments of this application, a battery apparatus may include one or more battery cell assemblies for providing voltage and capacity. A battery cell assembly may include multiple battery cells connected in series, parallel, or mixed connections via busbars. For example, a battery cell assembly is typically formed by arranging multiple battery cells; a battery cell assembly may also be a battery module, which is formed by arranging and fixing multiple battery cells into a single module. As an example, a battery module may be formed by bundling multiple battery cells together with cable ties.

[0062] The battery device can be a battery pack, which includes a housing and one or more individual battery cells housed within the housing. The individual battery cells can be battery modules, which can be housed within the housing by securing the battery modules to the housing; alternatively, multiple individual battery cells can be housed within the housing by directly securing them to the housing.

[0063] In embodiments of this application, the housing may include a first housing and a second housing. The first housing and the second housing are fastened together to form a closed space inside the housing for housing individual battery cells. Here, "closed" refers to covering or shutting down; it can be sealed or unsealed. The first housing may be a top cover or a bottom plate. For example, the housing may include a top cover, a frame, and a bottom plate. The top cover and the bottom plate are respectively connected to the frame, forming a closed space inside the housing for housing individual battery cells.

[0064] In this embodiment, the battery cell can be a rechargeable battery, which refers to a battery cell that can be recharged after discharge to activate the active materials and continue to be used. The battery cell can be a lithium-ion battery, sodium-ion battery, sodium-lithium-ion battery, lithium metal battery, sodium metal battery, lithium-sulfur battery, magnesium-ion battery, nickel-metal hydride battery, nickel-cadmium battery, lead-acid battery, etc., and this embodiment is not limited to these types. The battery cell can be cylindrical, flat, cuboid, or other shapes, and this embodiment is not limited to these shapes either. Battery cells are generally classified into three types according to their packaging method: cylindrical battery cells, square battery cells, and pouch battery cells, and this embodiment is not limited to these types either.

[0065] The technical solutions described in the embodiments of this application are applicable to various electrical devices that use individual battery cells, such as mobile phones, portable devices, laptops, electric vehicles, electric toys, power tools, vehicles, ships, and spacecraft. For example, spacecraft include airplanes, rockets, space shuttles, and spacecraft.

[0066] Currently, judging from market trends, the application of batteries is becoming increasingly widespread. Batteries are not only used in energy storage power systems such as hydropower, thermal power, wind power, and solar power plants, but also widely used 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 the application areas of power batteries, the market demand for them is also constantly increasing.

[0067] In related technologies, winding is a common method for assembling battery electrodes. This involves fixing the positive electrode, negative electrode, and separator onto a roller, and then winding them into an electrode assembly as the roller rotates. However, during the cyclic charging and discharging of the wound electrode assembly, the electrodes expand and contract, causing them to press against each other. Under high pressure, this can lead to electrode breakage, especially since the expansion force concentrates on the outer ring of the electrode assembly, making the outer electrodes more prone to breakage.

[0068] Based on this, this application proposes a wound electrode assembly, which includes a positive electrode sheet, a negative electrode sheet, and a separator. The separator is provided between the positive electrode sheet and the negative electrode sheet, and wrinkles are formed on the separator, which extends along the winding direction of the separator.

[0069] In the aforementioned wound electrode assembly, by providing a separator between the positive and negative electrodes with pleats, the surface of the separator in the pleated area protrudes beyond the surface of other areas of the separator. This increases the gap between the positive and negative electrodes, providing a buffer space. During charging and discharging, this buffer space alleviates the expansion force and reduces the compressive force between the electrodes, lowering the likelihood of breakage due to expansion and contraction during cyclic charging and discharging of the wound electrode assembly. In particular, it reduces the expansion force on the outer electrodes, thus reducing the likelihood of breakage and extending the service life of the wound electrode assembly. Furthermore, the gap between the positive and negative electrodes facilitates electrolyte diffusion and allows for better penetration into the interior of the wound electrode assembly, ensuring that at least a portion of the positive and negative electrodes are in full contact with the electrolyte, thereby improving the overall performance of the wound electrode assembly.

[0070] The vehicle disclosed in this application can be a new energy vehicle, which can be a pure electric vehicle, a hybrid electric vehicle, or a range-extended electric vehicle, etc. A battery device is installed inside the vehicle, and the battery device can be located at the bottom of the vehicle. The battery device can be used to power the vehicle, for example, it can serve as the vehicle's drive power source, replacing or partially replacing fuel or natural gas to provide driving power. The battery device can not only serve as the vehicle's drive power source but also as the vehicle's operating power source. The vehicle may also include a controller and a motor. The controller is used to control the battery device to supply power to the motor, for example, for the vehicle's starting, navigation, and operating power needs.

[0071] The following reference Figures 1-6 A wound electrode assembly 20 according to an embodiment of this application is described.

[0072] Reference Figures 1-3 In a first aspect, this application provides a wound electrode assembly 20, which includes a positive electrode 201, a negative electrode 202 and a separator 203. The separator 203 is provided between the positive electrode 201 and the negative electrode 202. The separator 203 has pleats 2033 formed on it, and the pleats 2033 extend along the winding direction of the separator 203.

[0073] The separator 203 is located between the positive electrode 201 and the negative electrode 202, and can play a role in isolation to prevent the positive electrode 201 and the negative electrode 202 from directly contacting each other and short-circuiting.

[0074] During the winding process of the separator 203 with the positive electrode 201 and the negative electrode 202, the separator 203 has a small thickness and low structural strength. Because pre-made creases are formed on the separator 203, at least a portion of the separator 203 is prone to wrinkles 2033 along the traces of the pre-made creases during the winding process. Since the wrinkles 2033 can form a folded structure, the thickness of the separator 203 in the corresponding area of ​​the wrinkles 2033 can be increased, thereby increasing the gap between the positive electrode 201 and the negative electrode 202.

[0075] For example, during the cyclic charging and discharging of the wound electrode assembly 20, the positive electrode 201 or the negative electrode 202 will expand. This expansion force makes the positive electrode 201 or the negative electrode 202 prone to breakage. In particular, the inner electrode will be squeezed outward after expansion, making the outer electrode more susceptible to expansion force and thus more prone to breakage. By placing a diaphragm 203 with pleats 2033 between the positive electrode 201 and the negative electrode 202, the gap between the positive electrode 201 and the negative electrode 202 can be increased. This gap can provide a certain buffer space between the positive electrode 201 and the negative electrode 202. The buffer space between the electrodes can alleviate the expansion force and reduce the squeezing force between the electrodes. This can reduce the possibility of the electrodes breaking due to expansion and contraction during the cyclic charging and discharging of the wound electrode assembly 20. In particular, it can reduce the expansion force borne by the outer electrode, thereby reducing the possibility of the outer electrode breaking and extending the service life of the wound electrode assembly 20.

[0076] In addition, the gap between the positive electrode 201 and the negative electrode 202 facilitates electrolyte diffusion and allows the electrolyte to better penetrate into the interior of the wound electrode assembly 20, so that at least a portion of the positive electrode 201 and the negative electrode 202 can make more sufficient contact with the electrolyte. Furthermore, this gap allows for a larger space between the positive electrode 201 and the negative electrode 202, which can accommodate more electrolyte. For example, during the cyclic charging and discharging of the battery cell 10, if a large amount of electrolyte in the inner ring is consumed, the electrolyte in the outer ring can serve as a supplementary electrolyte for the inner ring, quickly replenishing the inner ring. This can improve the internal cycling performance of the wound electrode assembly 20 and improve the overall performance of the wound electrode assembly 20.

[0077] In the above technical solution, by providing a separator 203 between the positive electrode 201 and the negative electrode 202, and forming wrinkles 2033 on the separator 203, the surface of the separator 203 in the area corresponding to the wrinkles 2033 can protrude from the surface of other areas of the separator 203. This increases the gap between the positive electrode 201 and the negative electrode 202. This gap can reserve a certain buffer space between the positive electrode 201 and the negative electrode 202. During charging and discharging, the buffer space between the electrodes can alleviate the expansion force and reduce the squeezing force between the electrodes, thereby reducing the electrode's stress in the wound electrode. The possibility of breakage due to expansion and contraction during the cyclic charging and discharging of the electrode assembly 20 is reduced, especially by reducing the expansion force borne by the outer electrode, thereby reducing the possibility of breakage of the outer electrode and extending the service life of the wound electrode assembly 20. Furthermore, the gap between the positive electrode 201 and the negative electrode 202 facilitates electrolyte diffusion and allows the electrolyte to better penetrate into the interior of the wound electrode assembly 20, so that at least a portion of the positive electrode 201 and the negative electrode 202 can make more sufficient contact with the electrolyte, which is beneficial to improving the overall performance of the wound electrode assembly 20.

[0078] Reference Figures 1-3 In some embodiments, the folds 2033 are formed as multi-layered folded structures.

[0079] For example, the fold 2023 can be formed into a two-layer folded structure or a three-layer folded structure, and the fold 2033 can be formed into a multi-layer folded structure. This can make the thickness of this separator 203 larger, thereby making the gap between the positive electrode 201 and the negative electrode 202 larger, so as to more effectively reduce the extrusion pressure between the electrodes.

[0080] In the above technical solution, the pleats 2033 of the multi-layer folded structure can make the thickness of the separator 203 larger, thereby making the gap between the positive electrode 201 and the negative electrode 202 larger, so as to more effectively reduce the extrusion pressure between the electrodes, thereby reducing the possibility of the electrodes breaking due to expansion and contraction during the cyclic charging and discharging of the wound electrode assembly 20. In particular, it can reduce the expansion force borne by the outer electrode, thereby effectively reducing the possibility of the outer electrode breaking.

[0081] Reference Figures 1-3 In some embodiments, at least some of the folds 2033 are formed as a three-layer folded structure.

[0082] The formation of at least some of the folds 2033 into a three-layer folded structure can include the following: for example, some of the folds 2033 can be formed into a three-layer folded structure; or, for example, all of the folds 2033 can be formed into a three-layer folded structure. By forming at least some of the folds 2033 into a three-layer folded structure, for example, the folds 2033 at opposite ends along the winding axis can be formed into a two-layer folded structure, while the folds 2033 along the winding axis and near the middle can be formed into a three-layer folded structure. This allows the diaphragm 203 in the region near the middle along the winding axis to have a larger thickness, thereby effectively reducing the compressive stress between the electrodes in this region.

[0083] In the above technical solution, at least some of the folds 2033 are formed as a three-layer folded structure, which allows for a larger thickness of this separator 203, resulting in a larger gap between the electrodes. This effectively reduces the compressive force between the electrodes, thereby reducing the possibility of the electrodes breaking due to expansion and contraction during the cyclic charging and discharging of the wound electrode assembly 20. (Refer to...) Figures 1-3 In some embodiments, there are multiple folds 2033, and at least some of the folds 2033 are arranged at intervals along the winding axis of the diaphragm 203.

[0084] The arrangement of at least some of the pleats 2033 along the winding axis of the diaphragm 203 can include the following: for example, some of the pleats 2033 can be arranged along the winding axis of the diaphragm 203; or, for another example, all the pleats 2033 can be arranged along the winding axis of the diaphragm 203.

[0085] The pleats 2033 are multiple, and at least some of the pleats 2033 are arranged at intervals along the winding axis of the separator 203. Multiple gaps can be formed between the positive electrode 201 and the negative electrode 202 along the winding axis of the separator 203. This allows multiple buffer spaces to be formed between the positive electrode 201 and the negative electrode 202 along the winding axis of the separator 203. During the cyclic charging and discharging of the wound electrode assembly 20, these spaced buffer spaces can more evenly reduce the compressive force between the electrodes, thereby effectively reducing the possibility of the positive electrode 201 or the negative electrode 202 breaking due to expansion and contraction during the cyclic charging and discharging of the wound electrode assembly 20.

[0086] In the above technical solution, by arranging multiple pleats 2033, and at least some of them, along the winding axis of the separator 203, multiple gaps can be formed between the positive electrode 201 and the negative electrode 202 along the winding axis of the separator 203. This allows multiple buffer spaces to be formed between the positive electrode 201 and the negative electrode 202 along the winding axis of the separator 203. These spaced buffer spaces can more evenly reduce the compressive force between the electrodes, thereby effectively reducing the possibility of the positive electrode 201 or the negative electrode 202 breaking due to expansion and contraction during the cyclic charging and discharging of the wound electrode assembly 20.

[0087] Reference Figures 1-3 In some embodiments, at least some of the folds 2033 are evenly spaced along the winding axis of the diaphragm 203.

[0088] At least some of the pleats 2033 are evenly spaced along the winding axis of the separator 203, which allows the gaps between the positive electrode 201 and the negative electrode 202 to be spaced along the winding axis of the separator 203. During the cyclic charging and discharging process of the wound electrode assembly 20, these gaps, which are evenly spaced along the winding axis of the separator 203, can better adapt to the volume changes of the positive electrode 201 or the negative electrode 202. This allows the expansion force borne by the positive electrode 201 or the negative electrode 202 to be more evenly distributed through these evenly spaced gaps, effectively preventing the expansion force from being too concentrated in one place. This significantly reduces the risk of the positive electrode 201 or the negative electrode 202 breaking due to the concentration of expansion force, effectively improving the overall performance of the wound electrode assembly 20 and extending the overall service life of the wound electrode assembly 20.

[0089] In the above technical solution, by arranging at least some of the pleats 2033 evenly at intervals along the winding axis of the separator 203, the gap between the positive electrode 201 and the negative electrode 202 can be evenly at intervals along the winding axis of the separator 203. This allows the expansion force borne by the positive electrode 201 or the negative electrode 202 to be more evenly distributed through these evenly distributed gaps, thereby significantly reducing the risk of breakage of the positive electrode 201 or the negative electrode 202 due to the concentration of expansion force. This effectively improves the overall performance of the wound electrode assembly 20 and extends the overall service life of the wound electrode assembly 20.

[0090] Reference Figures 1-3 In some embodiments, the width w1 of the fold 2033 ranges from 0.1 mm to 5 mm.

[0091] For example, the width w1 of the pleat 2033 can be 0.1mm, 1.5mm, 2.8mm, 4.2mm, 5mm, etc. By ensuring that the width w1 of the pleat 2033 is not less than 0.1mm, the pleat 2033 can be relatively wide, so that after at least part of the separator 203 is deformed, a sufficiently wide gap can be formed between the positive electrode 201 and the negative electrode 202. This gap can provide buffer space for the expansion of the positive electrode 201 or the negative electrode 202, effectively reducing the possibility of the positive electrode 201 or the negative electrode 202 breaking due to expansion and contraction. By ensuring that the width w1 of the pleat 2033 is not greater than 5mm, while ensuring that the width of the pleat 2033 is wide enough to form a certain gap between the positive electrode 201 and the negative electrode 202, the overall size of the wound electrode assembly 20 can be smaller, avoiding the overall size of the wound electrode assembly 20 being too large due to excessive gaps between the electrodes.

[0092] For example, when the wound electrode assembly 20 is used in a battery cell 10, the battery cell 10 includes a housing 101, and the wound electrode assembly 20 is disposed inside the housing 101. If the overall size of the wound electrode assembly 20 is too large when the volume of the housing 101 remains unchanged, it will cause the gap between the wound electrode assembly 20 and the housing 101 to be too small. This will cause the outer ring of the wound electrode assembly 20 to be squeezed between the housing 101 during cyclic charging and discharging. By ensuring that the width w1 of the pleats 2033 is no more than 5mm, the overall size of the wound electrode assembly 20 can be made smaller, thereby reducing the squeeze between the outer electrode and the housing 101 and reducing the possibility of the housing 101 expanding.

[0093] In the above technical solution, by having the width w1 of the pleats 2033 range from 0.1mm to 5mm, the gap width formed between the positive electrode 201 and the negative electrode 202 after at least part of the deformation of the separator 203 and the structural strength of the separator 203 itself can be better balanced. While effectively reducing the possibility of the positive electrode 201 or the negative electrode 202 breaking due to expansion and contraction, the overall size of the wound electrode assembly 20 can be made smaller.

[0094] Reference Figures 1-3 In some embodiments, the width w1 of the fold 2033 ranges from 0.15 mm to 2 mm.

[0095] For example, the width w1 of the pleats 2033 can be 0.15mm, 0.16mm, 0.17mm, 0.18mm, 2mm, etc. By ensuring that the width w1 of the pleats 2033 is not less than 0.15mm, the gap formed between the positive electrode 201 and the negative electrode 202 after at least a part of the separator 203 is deformed along the pleats 2033 is sufficiently wide, which can effectively alleviate the expansion force between the electrodes during the charging and discharging process of the wound electrode assembly 20. By ensuring that the width w1 of the pleats 2033 is not greater than 2mm, the possibility of breakage caused by expansion and contraction of the positive electrode 201 or the negative electrode 202 can be effectively reduced, while the overall size of the wound electrode assembly 20 can be made smaller.

[0096] In the above technical solution, by having the width w1 of the pleats 2033 range from 0.15mm to 2mm, the gap width formed between the positive electrode 201 and the negative electrode 202 after at least part of the diaphragm 203 is deformed, as well as the overall size of the wound electrode assembly 20, can be better balanced.

[0097] Reference Figures 1-3 In some embodiments, the diaphragm 203 includes a planar portion 2031 and a bent portion 2032 arranged alternately along the winding direction of the diaphragm 203. In the winding direction of the diaphragm 203, the planar portion 2031 extends in a straight line and the bent portion 2032 extends in an arc. The bent portion 2032 is provided with pleats 2033.

[0098] For example, the positive electrode 201 includes a first planar portion 2011 and a first bent portion 2012 arranged alternately along the winding direction of the positive electrode 201, and the negative electrode 202 includes a second planar portion 2021 and a second bent portion 2022 arranged alternately along the winding direction of the negative electrode 202. The first planar portion 2011, the second planar portion 2021 and the planar portion 2031 are respectively corresponding, and the planar portion 2031 is located between the first planar portion 2011 and the second planar portion 2021. The first bent portion 2012, the second bent portion 2022 and the bent portion 2032 are respectively corresponding, and the bent portion 2032 is located between the first bent portion 2012 and the second bent portion 2022. By providing pleats 2033 in the bending portion 2032 of the diaphragm 203, the gap between the first bending portion 2012 and the second bending portion 2022 of the positive electrode 201 and the negative electrode 202 can be increased. This gap can reserve a certain buffer space between the first bending portion 2012 and the second bending portion 2022. Compared with the first flat portion 2011 and the second flat portion 2021, there is a certain bending force at the first bending portion 2012 and the second bending portion 2022. During the charging and discharging process of the wound electrode assembly 20, the buffer space between the first bending portion 2012 and the second bending portion 2022 can alleviate the expansion force and the bending force of the first bending portion 2012 and the second bending portion 2022. This can effectively reduce the possibility of the first bending portion 2012 or the second bending portion 2022 breaking due to excessive concentration of expansion force or bending force, which is beneficial to extending the service life of the wound electrode assembly 20.

[0099] In the above technical solution, by providing pleats 2033 in the bending portion 2032, the gap between the positive electrode 201 and the negative electrode 202 corresponding to the bending portion 2032 can be increased, so as to buffer the bending force and expansion force at the electrode corresponding to the bending portion 2032, thereby effectively reducing the possibility of the positive electrode 201 or the negative electrode 202 breaking due to excessive concentration of expansion force or bending force, which is beneficial to extending the service life of the wound electrode assembly 20.

[0100] Reference Figures 1-3 In some embodiments, the planar portion 2031 is provided with pleats 2033.

[0101] For example, the positive electrode 201 includes a first planar portion 2011 arranged alternately along the winding direction of the positive electrode 201, and the negative electrode 202 includes a second planar portion 2021 arranged alternately along the winding direction of the negative electrode 202. The first planar portion 2011, the second planar portion 2021 and the planar portion 2031 are respectively corresponding, and the planar portion 2031 is located between the first planar portion 2011 and the second planar portion 2021. By providing pleats 2033 on the flat portion 2031 of the diaphragm 203, the gap between the first flat portion 2011 and the second flat portion 2021 of the positive electrode 201 and the negative electrode 202 can be increased. This gap can reserve a certain buffer space between the first flat portion 2011 and the second flat portion 2021. During charging and discharging, the expansion force is relieved by the buffer space between the first flat portion 2011 and the second flat portion 2021, thereby effectively reducing the possibility of the first flat portion 2011 or the second flat portion 2021 breaking due to excessive expansion force, which is beneficial to extending the service life of the wound electrode assembly 20.

[0102] In the above technical solution, by providing pleats 2033 in the flat portion 2031, the gap between the positive electrode 201 and the negative electrode 202 corresponding to the flat portion 2031 can be increased. This gap can alleviate the expansion force between the positive electrode 201 and the negative electrode 202 during charging and discharging, reduce the squeezing force between the electrodes, thereby effectively reducing the possibility of breakage of the positive electrode 201 or the negative electrode 202, which is beneficial to extending the service life of the wound electrode assembly 20.

[0103] Reference Figures 1-3 In some embodiments, at least some of the folds 2033 on the planar portion 2031 and at least some of the folds 2033 on the bent portion 2032 are connected in the winding direction of the diaphragm 203 to form continuous folds 2033.

[0104] The connection of at least some folds 2033 on the planar portion 2031 and at least some folds 2033 on the bent portion 2032 to form continuous folds 2033 in the winding direction of the diaphragm 203 can include the following: for example, a portion of the folds 2033 on the planar portion 2031 and a portion of the folds 2033 on the bent portion 2032 can be connected to form continuous folds 2033 in the winding direction of the diaphragm 203; or, for another example, a portion of the folds 2033 on the planar portion 2031 and the bent portion 2032 can be connected to form continuous folds 2033 in the winding direction of the diaphragm 203. All the pleats 2033 on 32 are connected in the winding direction of the diaphragm 203 to form continuous pleats 2033. Alternatively, all the pleats 2033 on the flat portion 2031 and a portion of the pleats 2033 on the bent portion 2032 can be connected in the winding direction of the diaphragm 203 to form continuous pleats 2033. For example, all the pleats 2033 on the flat portion 2031 and all the pleats 2033 on the bent portion 2032 can be connected in the winding direction of the diaphragm 203 to form continuous pleats 2033.

[0105] At least some of the folds 2033 on the planar portion 2031 and at least some of the folds 2033 on the bent portion 2032 are connected in the winding direction of the separator 203 to form continuous folds 2033. This makes the processing and manufacturing of the separator 203 more convenient. The continuous folds 2033 can also enhance the connection strength between the planar portion 2031 and the bent portion 2032. During the cyclic charging and discharging process of the wound electrode assembly 20, the continuous folds 2033 can guide the expansion force of the positive electrode 201 or negative electrode 202 on the separator 203 to be transmitted and dispersed more smoothly between the planar portion 2031 and the bent portion 2032, avoiding excessive concentration of expansion force at one point, thereby reducing the possibility of breakage of the positive electrode 201 or negative electrode 202 due to concentrated expansion force.

[0106] In the above technical solution, at least some of the pleats 2033 on the flat portion 2031 and at least some of the pleats 2033 on the bent portion 2032 are connected in the winding direction of the diaphragm 203 to form continuous pleats 2033. This makes the processing and manufacturing of the diaphragm 203 more convenient. The continuous pleats 2033 can also enhance the connection strength between the flat portion 2031 and the bent portion 2032. The continuous pleats 2033 can also guide the expansion force of the positive electrode 201 or negative electrode 202 on the diaphragm 203 to be transmitted and dispersed more smoothly between the flat portion 2031 and the bent portion 2032, avoiding excessive concentration of expansion force at a certain point, thereby reducing the possibility of the positive electrode 201 or negative electrode 202 breaking due to concentrated expansion force.

[0107] Reference Figures 1-3 In some embodiments, the arrangement density of the folds 2033 on the bent portion 2032 is greater than or equal to the arrangement density of the folds 2033 on the flat portion 2031.

[0108] For example, the arrangement density of the pleats 2033 on the bent portion 2032 can be equal to the arrangement density of the pleats 2033 on the flat portion 2031. This makes the diaphragm 203 easier to manufacture and the processing technology simpler. Of course, the arrangement density of the pleats 2033 on the bent portion 2032 can also be greater than the arrangement density of the pleats 2033 on the flat portion 2031. Compared with the flat portion 2031, the bent portion 2032 has a certain bending force and is more prone to local stress concentration. By making the arrangement density of the pleats 2033 on the bent portion 2032 greater than the arrangement density of the pleats 2033 on the flat portion 2031, the expansion force and bending force of the electrode corresponding to the bent portion 2032 can be more effectively dispersed, thereby effectively reducing the possibility of breakage of the positive electrode 201 or negative electrode 202 corresponding to the bent portion 2032, and thus improving the overall service life of the wound electrode assembly 20.

[0109] In the above technical solution, the arrangement density of the pleats 2033 on the bending portion 2032 can be equal to the arrangement density of the pleats 2033 on the flat portion 2031, which makes the diaphragm 203 easier to manufacture and the processing technology simpler. Since the arrangement density of the pleats 2033 on the bending portion 2032 is greater than that on the flat portion 2031, the expansion force and bending force of the electrode corresponding to the bending portion 2032 can be more effectively dispersed, thereby effectively reducing the possibility of breakage of the positive electrode 201 or negative electrode 202 corresponding to the bending portion 2032, and thus improving the overall service life of the wound electrode assembly 20.

[0110] Reference Figures 1-3 In some embodiments, the ratio of the extension length of the pleats 2033 in the winding direction of the diaphragm 203 to the winding length of the diaphragm 203 is greater than 0.8.

[0111] For example, the ratio of the extension length of the pleats 2033 in the winding direction of the separator 203 to the winding length of the separator 203 can be 0.82, 0.85, 0.9, 0.95, 1.0, etc. By making the ratio of the extension length of the pleats 2033 in the winding direction of the separator 203 to the winding length of the separator 203 greater than 0.8, the extension length of the pleats 2033 in the winding direction of the separator 203 can be longer, so that the pleats 2033 can more comprehensively and effectively buffer the expansion force between the positive electrode 201 or the negative electrode 202, avoid the phenomenon of local expansion force concentration in the positive electrode 201 or the negative electrode 202 due to the lack of buffering by the pleats 2033, and effectively reduce the possibility of breakage of the positive electrode 201 or the negative electrode 202.

[0112] In the above technical solution, by making the ratio of the extension length of the pleats 2033 in the winding direction of the separator 203 to the winding length of the separator 203 greater than 0.8, the extension length of the pleats 2033 in the winding direction of the separator 203 can be longer, so that the pleats 2033 can more comprehensively and effectively buffer the expansion force between the positive electrode 201 or the negative electrode 202, effectively reducing the possibility of breakage of the positive electrode 201 or the negative electrode 202.

[0113] Reference Figure 1 , Figure 3 and Figure 4 In some embodiments, the thickness of the diaphragm 203 ranges from 3 μm to 30 μm.

[0114] For example, the thickness of the diaphragm 203 can be in the range of 3μm, 10μm, 15μm, 20μm, 25μm, 30μm, etc. By ensuring that the thickness of the diaphragm 203 is not less than 3μm, the diaphragm 203 can have a certain structural strength, for example, the possibility of damage to the diaphragm 203 during winding is relatively small. By ensuring that the thickness of the diaphragm 203 is not greater than 30μm, it is easier for the diaphragm 203 to form wrinkles 2033 in a predetermined area. For example, if the thickness of the diaphragm 203 is thicker, it is more difficult for the diaphragm 203 to form wrinkles 2033 in the predetermined area.

[0115] In the above technical solution, the thickness of the diaphragm 203 is in the range of 3μm to 30μm, which enables the diaphragm 203 to have a certain structural strength and also enables the diaphragm 203 to form folds 2033 well.

[0116] Reference Figure 1 , Figure 3 and Figure 4 In some embodiments, the thickness of the diaphragm 203 ranges from 5 μm to 15 μm.

[0117] For example, the thickness of the diaphragm 203 can be in the range of 5μm, 7μm, 10μm, 12μm, 15μm, etc. By ensuring that the thickness of the diaphragm 203 is not less than 5μm, the diaphragm 203 can have a stronger structural strength, further reducing the possibility of damage to the diaphragm 203. By ensuring that the thickness of the diaphragm 203 is not greater than 15μm, the diaphragm 203 can more easily form wrinkles 2033 in the predetermined area.

[0118] In the above technical solution, by using a thickness range of 5μm to 15μm for the diaphragm 203, the structural strength of the diaphragm 203 and the possibility of the diaphragm 203 forming wrinkles 2033 in a predetermined area can be well balanced. While the diaphragm 203 has high structural strength, it makes it easier for the diaphragm 203 to form wrinkles 2033 in the predetermined area.

[0119] Reference Figure 4Secondly, this application provides a battery cell 10, including: a housing 101; and a wound electrode assembly 20 according to the first aspect of this application, wherein the wound electrode assembly 20 is disposed within the housing 101.

[0120] The housing 101 can provide some support and protection for the wound electrode assembly 20, preventing the wound electrode assembly 20 from being damaged by external impact.

[0121] In the above technical solution, by setting the above-mentioned wound electrode assembly 20, the battery cell 10 can have a longer service life and better performance.

[0122] Reference Figure 5 Thirdly, this application provides a battery device 100, including: a battery cell 10 according to the second aspect of this application.

[0123] In the above technical solution, by providing the aforementioned battery cell 10, the battery device 100 can have a longer service life and better performance.

[0124] Reference Figure 6 Fourthly, this application provides an electrical device 1000, including: a battery device 100 according to the third aspect of this application.

[0125] In the above technical solution, by providing the battery device 100, it is beneficial to improve the overall performance of the power-consuming device 1000.

[0126] In some embodiments, the electrical device 1000 is a vehicle.

[0127] For example, the battery device 100 can be located at the bottom of the vehicle body 200. When the battery device 100 is used in a vehicle, the vertical direction can be referred to as the Z direction in the attached drawings.

[0128] In the above technical solution, when the battery device 100 is used in a vehicle, the wound electrode assembly 20 in the battery device 100 increases the gap between the positive electrode 201 and the negative electrode 202. This gap can reserve a certain buffer space between the positive electrode 201 and the negative electrode 202, thereby reducing the possibility of the positive electrode 201 or the negative electrode 202 breaking due to expansion during the charging and discharging of the battery cell 10, which is beneficial to improving the overall performance of the vehicle.

[0129] The following reference Figures 1-4 Describes a wound electrode assembly 20 according to some embodiments of this application.

[0130] Reference Figures 1-4In this embodiment, the wound electrode assembly 20 includes a positive electrode 201, a negative electrode 202, and a separator 203. The separator 203 is disposed between the positive electrode 201 and the negative electrode 202. The separator 203 has pleats 2033 formed on it, and the pleats 2033 extend along the winding direction of the separator 203. There are multiple pleats 2033, and at least some of the pleats 2033 are evenly spaced along the winding axis of the separator 203.

[0131] The diaphragm 203 includes a planar portion 2031 and a bent portion 2032 arranged alternately along the winding direction of the diaphragm 203. In the winding direction of the diaphragm 203, the planar portion 2031 extends in a straight line and the bent portion 2032 extends in an arc. The bent portion 2032 is provided with pleats 2033 and the planar portion 2031 is provided with pleats 2033.

[0132] At least some of the pleats 2033 on the flat portion 2031 and at least some of the pleats 2033 on the bent portion 2032 are connected in the winding direction of the diaphragm 203 to form continuous pleats 2033. The arrangement density of the pleats 2033 on the bent portion 2032 is greater than the arrangement density of the pleats 2033 on the flat portion 2031, and the ratio of the extension length of the pleats 2033 in the winding direction of the diaphragm 203 to the winding length of the diaphragm 203 is greater than 0.8.

[0133] By providing a separator 203 between the positive electrode 201 and the negative electrode 202, and forming wrinkles 2033 on the separator 203, a certain gap can be formed between the positive electrode 201 and the negative electrode 202. This gap can reserve a certain buffer space between the positive electrode 201 and the negative electrode 202. During charging and discharging, the buffer space between the electrodes can alleviate the expansion force and reduce the squeezing force between the electrodes. This can reduce the possibility of the electrodes breaking due to expansion and contraction during the cyclic charging and discharging of the wound electrode assembly 20. In particular, it can reduce the expansion force borne by the outer electrode, thereby reducing the possibility of the outer electrode breaking and extending the service life of the wound electrode assembly 20. Furthermore, the gap between the positive electrode 201 and the negative electrode 202 can also facilitate the diffusion of the electrolyte and allow the electrolyte to better penetrate into the interior of the wound electrode assembly 20, so that at least part of the positive electrode 201 and the negative electrode 202 can be in more sufficient contact with the electrolyte, which is beneficial to improving the overall performance of the wound electrode assembly 20.

[0134] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0135] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. A wound electrode assembly, characterized by, The application relates to a battery cell. The battery cell comprises: a positive electrode sheet; a negative electrode sheet; 2. The jellyroll electrode assembly according to claim 1, characterized by a separator, the separator being arranged between the positive electrode sheet and the negative electrode sheet, and the separator being provided with a plurality of folds, the folds extending along a winding direction of the separator.

3. The jellyroll electrode assembly according to claim 2, characterized by The folds are formed into a multi-layer folding structure.

4. The jellyroll electrode assembly according to claim 1, characterized by At least part of the folds are formed into a three-layer folding structure.

5. The jellyroll electrode assembly according to claim 4, characterized by The folds are arranged in a plurality of groups, and at least part of the folds in each group are arranged along an axis of the separator.

6. The jellyroll electrode assembly according to claim 1, characterized by At least part of the folds are arranged uniformly along the axis of the separator.

7. The jellyroll electrode assembly according to claim 6, characterized by The width of the folds ranges from 0.1mm to 5mm.

8. The jellyroll electrode assembly according to claim 1, characterized by, The width of the folds ranges from 0.15mm to 2mm.

9. The jellyroll electrode assembly according to claim 8, characterized by The separator comprises a plurality of flat portions and a plurality of bending portions arranged alternately along the winding direction of the separator, the flat portions extending along a straight line and the bending portions extending along an arc line along the winding direction of the separator, and the folds are arranged on the bending portions.

10. The jellyroll electrode assembly according to claim 9, characterized by The folds are arranged on the flat portions.

11. The jellyroll electrode assembly according to claim 9, characterized by At least part of the folds on the flat portions and at least part of the folds on the bending portions are connected into continuous folds along the winding direction of the separator.

12. The jellyroll electrode assembly according to claim 1, characterized by The arrangement density of the folds on the bending portions is greater than or equal to the arrangement density of the folds on the flat portions.

13. The jellyroll electrode assembly according to claim 1, characterized by, The ratio of the extension length of the folds along the winding direction of the separator to the winding length of the separator is greater than 0.

8.

14. The jellyroll electrode assembly according to claim 13, characterized by The thickness of the separator ranges from 3um to 30um.

15. A battery cell, characterized by The thickness of the separator ranges from 5um to 15um. The application relates to a battery cell. The battery cell comprises:

16. A battery device characterized by comprising: a housing; a wound electrode assembly according to any one of claims 1-14, the wound electrode assembly being arranged in the housing.

17. An electrical device, comprising: The application relates to a battery cell. The battery cell comprises: a battery cell according to claim 15. The application relates to a battery device. The battery device comprises: a battery device according to claim 16.

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