Winding apparatus

Abstract

The application relates to the battery technical field and provides a winding device for manufacturing an electrode assembly, the winding device comprising: a first feeding mechanism for providing a positive electrode sheet and performing a cutting operation on the positive electrode sheet to form a first positive electrode sheet and a second positive electrode sheet; a second feeding mechanism for providing a negative electrode sheet; a third feeding mechanism for providing a diaphragm; a winding mechanism comprising a winding needle, the winding needle being used for winding the positive electrode sheet, the diaphragm and the negative electrode sheet into the electrode assembly; and a first gluing mechanism for conveying the positive electrode sheet, the diaphragm and the negative electrode sheet to the winding mechanism and gluing an adhesive to the winding starting end of the negative electrode sheet and the diaphragm; and the winding starting end of the first positive electrode sheet and the negative electrode sheet are oppositely arranged on the winding needle at the innermost circle of the electrode assembly. The winding device provided by the application can effectively utilize the negative electrode sheet at the innermost circle of the battery monomer and improve the energy density.

Description

[0001] This application is a divisional application based on application number 202511727584.7, filed on November 24, 2025, entitled "Battery Cell, Winding Equipment, Battery Device and Electrical Appliance". The entire contents of the original application are incorporated herein by reference. Technical Field

[0002] This application relates to the field of battery technology, and in particular to a battery cell, a winding device, a battery assembly, and an electrical device. Background Technology

[0003] In recent years, new energy vehicles have experienced rapid development. In the field of electric vehicles, the power battery is a core component, used to provide electrical energy to electric vehicles. Therefore, the performance requirements for batteries are quite high.

[0004] The battery cells inside a battery are formed by inserting an electrode assembly into a casing and then injecting electrolyte. The electrode assembly typically includes a positive electrode, a negative electrode, and a separator wound together. However, in related technologies, the innermost negative electrode is often not effectively utilized, affecting the energy density of the battery cell. Summary of the Invention

[0005] The purpose of this application is to provide a battery cell, a winding device, a battery assembly, and an electrical device, with the aim of improving the energy density of the battery cell.

[0006] To achieve the above objectives, the technical solution adopted in the embodiments of this application is as follows: In a first aspect, embodiments of this application provide a battery cell, comprising: a casing; and an electrode assembly disposed within the casing, the electrode assembly including a positive electrode sheet, a separator, and a negative electrode sheet wound together; the separator is disposed between the positive electrode sheet and the negative electrode sheet; the positive electrode sheet includes a first positive electrode sheet and a second positive electrode sheet spaced apart along the winding direction of the electrode assembly, the second positive electrode sheet including a plurality of alternately arranged straight positive electrode portions and bent positive electrode portions; the negative electrode sheet includes a plurality of alternately arranged straight negative electrode portions and bent negative electrode portions, the plurality of straight negative electrode portions and bent negative electrode portions... The electrode straight portion includes a first negative electrode straight portion and a second negative electrode straight portion. Among the plurality of negative electrode straight portions, the one closest to the winding start end of the negative electrode sheet along the winding direction is the first negative electrode straight portion. The second negative electrode straight portion is connected to the first negative electrode straight portion through the negative electrode bending portion. Along the thickness direction of the electrode assembly, at least one first positive electrode sheet is located between the first negative electrode straight portion and the second negative electrode straight portion. The electrode assembly also includes an adhesive, and the winding start end of the negative electrode sheet is adhered to the diaphragm through the adhesive.

[0007] In the battery cell provided in this application embodiment, the first positive electrode is located between the first and second negative electrode flat portions, so that both the innermost positive and negative electrode portions can participate in the electrochemical reaction. This solves the problem that the innermost portion of the negative electrode cannot be effectively utilized, improves the utilization rate of the electrode active material, and increases the energy density of the battery cell. At the same time, the starting end of the negative electrode winding is attached to the separator through an adhesive, which improves the winding feeding speed and winding efficiency of the electrode assembly, and improves the alignment accuracy between the negative electrode and the separator, thereby improving the manufacturing efficiency and yield of the electrode assembly.

[0008] In some embodiments, there are multiple first positive electrode sheets, which are arranged at intervals along the winding direction; along the thickness direction of the electrode assembly, each first positive electrode sheet is located between two adjacent negative electrode straight portions.

[0009] By adopting the above technical solution, multiple first positive electrode sheets can be distributed in multiple rings in the inner circle, which further improves the problem of breakage and powder shedding of positive electrode sheets in the inner circle due to large bending.

[0010] In some embodiments, with the thickness direction of the electrode assembly as the projection direction, the projections of the first negative electrode straight portion and the second negative electrode straight portion respectively cover the first positive electrode sheet.

[0011] By adopting the above technical solution, the first positive electrode sheet can be completely covered by the projection of the adjacent negative electrode flat portion, so as to meet the requirement of the electrode assembly for excessive design of negative electrode active material.

[0012] In some embodiments, in the innermost ring of the negative electrode sheet, the first positive electrode sheet and the first negative electrode straight portion are separated by a membrane.

[0013] By adopting the above technical solutions, the problem of redundant diaphragm winding has been improved, the spatial layout has been optimized, and the energy density of individual battery cells has been further enhanced.

[0014] In some embodiments, along the winding direction, the first negative electrode straight portion is located downstream of the first positive electrode sheet of the innermost ring.

[0015] By adopting the above technical solution, the first positive electrode and the negative electrode can be wound sequentially, so that the negative electrode can be positioned opposite the first positive electrode in the innermost circle of the electrode assembly, and the first positive electrode and the negative electrode are separated by only one layer of separator, thereby improving the energy density of the battery cell.

[0016] In some embodiments, the adhesive is offset from the first positive electrode sheet of the innermost ring along the thickness direction of the electrode assembly.

[0017] By adopting the above technical solution, the bonding component can be made to avoid the first positive electrode sheet of the innermost ring. The first positive electrode sheet will not be over-voltaged or damaged due to the bonding component, thus improving the stability of the battery cell.

[0018] In some embodiments, the electrode assembly includes a flat region and corner regions located at both ends of the flat region, the positive electrode flat portion and the negative electrode flat portion are located in the flat region, the positive electrode bent portion and the negative electrode bent portion are located in the corner regions, wherein the adhesive is located in the corner regions.

[0019] By adopting the above technical solution, the bonding component can effectively avoid the first positive electrode, reducing the risk of overvoltage on the positive electrode.

[0020] In some embodiments, there are multiple first positive electrode sheets arranged at intervals, and each first positive electrode sheet is located between two adjacent negative electrode straight portions along the thickness direction of the electrode assembly. Along the winding direction, the adhesive is located between the innermost first positive electrode sheet and the next innermost first positive electrode sheet; or, there is only one first positive electrode sheet, and along the winding direction, the adhesive is located between the first positive electrode sheet and the second positive electrode sheet.

[0021] By adopting the above technical solution, the adhesive can avoid the first positive electrode and the second positive electrode, reducing the risk of the inner positive electrode breaking brittlely and shedding powder due to overvoltage.

[0022] In some embodiments, along the thickness direction of the electrode assembly, the innermost first positive electrode sheet is offset from the adhesive, and the length of the innermost first positive electrode sheet is less than the length of the flat region.

[0023] By adopting the above technical solution, the risk of overvoltage caused by the bonding components in the first positive electrode sheet is further reduced.

[0024] In some embodiments, the diaphragm includes a first diaphragm and a second diaphragm, wherein the first diaphragm, the positive electrode, the second diaphragm, and the negative electrode are sequentially stacked and wound together; the starting end of the winding of the negative electrode is attached to the second diaphragm by the adhesive.

[0025] By adopting the above technical solution, the negative electrode is disposed on one side of the first diaphragm, the positive electrode, and the second diaphragm, and the negative electrode can be easily attached to the second diaphragm using an adhesive.

[0026] In some embodiments, the first positive electrode and the first separator are rolled together to form a composite sheet, or the first positive electrode and the second separator are rolled together to form a composite sheet.

[0027] By adopting the above technical solution, the first positive electrode sheet can be combined with the first or second separator, which improves the alignment accuracy between the first positive electrode sheet and the separator. Furthermore, the first positive electrode sheet can enter the winding needle together with the first or second separator. On the one hand, the first positive electrode sheet is less likely to detach or wrinkle when entering the winding needle. On the other hand, it improves the winding feeding speed and winding efficiency. Moreover, the fact that the first positive electrode sheet can enter the winding needle together with the first or second separator can also reduce the length of redundant winding at the head of the separator.

[0028] In some embodiments, the first positive electrode and the second positive electrode are both bonded to the second separator by roll forming to form a composite sheet.

[0029] By adopting the above technical solution, the pre-composite of the positive electrode sheet and the second separator was realized, which improved the feeding speed of the incoming material winding needle and the winding efficiency. At the same time, it also improved the alignment accuracy of the positive electrode sheet and the second separator, and solved the problems of misalignment, wrinkling and uneven stacking of the positive electrode sheet under high-speed winding.

[0030] In some embodiments, the positive electrode further includes at least one third positive electrode, which is spaced apart from the second positive electrode and is stacked on the side of the positive electrode straight portion away from the winding center of the electrode assembly.

[0031] By adopting the above technical solution, the third positive electrode sheet can fill the arc-shaped outer space naturally formed by the winding structure, thereby improving space utilization and the energy density of the battery cell. The third positive electrode sheet avoids the corner area, reducing the risk of electrode breakage and battery cell short circuit caused by external forces on the outer ring, and improving the reliability of the battery cell.

[0032] Secondly, embodiments of this application provide a winding device for manufacturing an electrode assembly. The winding device includes: a first feeding mechanism for providing a positive electrode sheet and cutting the positive electrode sheet to form a first positive electrode sheet and a second positive electrode sheet; a second feeding mechanism for providing a negative electrode sheet; a third feeding mechanism for providing a separator; a winding mechanism including a winding needle for winding the positive electrode sheet, the separator, and the negative electrode sheet into an electrode assembly; and a first adhesive applicator for conveying the positive electrode sheet, the separator, and the negative electrode sheet to the winding mechanism and attaching an adhesive to the winding start end of the negative electrode sheet and the separator; wherein, in the innermost ring of the electrode assembly, the winding start ends of the first positive electrode sheet and the negative electrode sheet are positioned opposite each other on the winding needle.

[0033] The winding equipment provided in this application includes a first feeding mechanism for providing a positive electrode sheet, a second feeding mechanism for providing a negative electrode sheet, a third feeding mechanism for providing a separator, and a winding mechanism. The first feeding mechanism can cut the positive electrode sheet to form a first positive electrode sheet and a second positive electrode sheet. In the innermost ring of the electrode assembly, the winding start ends of the first positive electrode sheet and the negative electrode sheet are arranged opposite to each other on the winding needle. In this way, both the positive and negative electrode sheets in the innermost ring can participate in the electrochemical reaction, solving the problem that the innermost part of the electrode sheet cannot be effectively utilized, improving the utilization rate of the active material of the electrode sheet, and improving the energy density of the battery cell. The first adhesive bonding mechanism attaches the adhesive to the winding start end of the negative electrode sheet and the separator, improving the winding efficiency and the manufacturing yield of the electrode assembly.

[0034] In some embodiments, along the conveying direction of the first adhesive bonding mechanism, the starting end of the winding of the negative electrode sheet is located downstream of the first positive electrode sheet; wherein, there are multiple first positive electrode sheets arranged sequentially at intervals, and the adhesive is located between the first and second first positive electrode sheets; or, there is only one first positive electrode sheet, and the adhesive is located between the first and second positive electrode sheets.

[0035] By adopting the above technical solution, after winding, the first positive electrode sheet is positioned opposite the negative electrode sheet in the innermost ring of the electrode assembly. Furthermore, the adhesive can avoid the positive electrode sheet in the inner ring, reducing the risk of the positive electrode sheet in the inner ring breaking brittlely and shedding powder due to overvoltage.

[0036] In some embodiments, the winding mechanism includes a winding needle, which is a clamping winding needle or an adsorption winding needle; The negative electrode is attached to the surface of the winding needle, which rotates to wind the positive electrode, the separator, and the negative electrode in sequence.

[0037] By adopting the above technical solution, the negative electrode sheet can be directly attached to the surface of the winding needle, so that the negative electrode sheet is located in the innermost circle of the electrode assembly, eliminating the need for multiple empty turns of the diaphragm and solving the problem of redundant winding of the diaphragm.

[0038] In some embodiments, the diaphragm includes a first diaphragm and a second diaphragm, and the third feeding mechanism includes a first diaphragm feeding assembly for providing the first diaphragm and a second diaphragm feeding assembly for providing the second diaphragm; the first adhesive applicator is used to convey the stacked first diaphragm, the positive electrode sheet, the second diaphragm and the negative electrode sheet to the winding mechanism, and to attach the adhesive to the winding start end of the negative electrode sheet and the second diaphragm.

[0039] By adopting the above technical solution, since the second diaphragm and the negative electrode sheet are adjacent and stacked, the first adhesive bonding mechanism can provide an adhesive and attach the adhesive to the winding start end of the negative electrode sheet and the second diaphragm; the winding mechanism can wind the electrode sheet and the diaphragm into an electrode assembly, so that the first positive electrode sheet and the negative electrode sheet are arranged opposite each other in the innermost circle; after the electrode assembly is wound and shaped, the first positive electrode sheet is located between the first negative electrode straight portion and the second negative electrode straight portion in the negative electrode sheet.

[0040] In some embodiments, the winding apparatus further includes a composite mechanism for rolling and bonding the first positive electrode sheet with one of the first diaphragm and the second diaphragm to form a composite sheet body.

[0041] By adopting the above technical solution, the composite mechanism combines the first positive electrode sheet with the first or second separator, improving the alignment accuracy between the first positive electrode sheet and the separator. Furthermore, the first positive electrode sheet can enter the winding needle together with the first or second separator. On the one hand, the first positive electrode sheet is less likely to detach from the separator or wrinkle when entering the winding needle. On the other hand, it improves the winding feeding speed and winding efficiency. Moreover, the fact that the first positive electrode sheet can be wound together with the first or second separator also reduces the redundant winding length of the separator head.

[0042] In some embodiments, the composite mechanism is used to roll-press the first positive electrode sheet and the second positive electrode sheet together with the second diaphragm in sequence to form a composite sheet body.

[0043] By adopting the above technical solution, the composite mechanism combines the first positive electrode sheet and the second positive electrode sheet with the second separator, realizing the pre-composite of the positive electrode sheet and the second separator, improving the feeding speed of the incoming material winding needle, improving the winding efficiency, and also improving the alignment accuracy of the positive electrode sheet and the second separator.

[0044] In some embodiments, the first feeding mechanism includes a first feeding assembly and a second feeding assembly for releasing the positive electrode sheet; the composite mechanism includes a first composite roller group and a second composite roller group, the first composite roller group being disposed downstream of the first feeding assembly and the second diaphragm feeding assembly for composite the first positive electrode sheet with the second diaphragm; the second composite roller group being disposed downstream of the second feeding roller and the second diaphragm feeding assembly for composite the second positive electrode sheet with the second diaphragm; the second diaphragm and the first and second positive electrode sheets on the second diaphragm are formed into a composite sheet body.

[0045] By adopting the above technical solution, the first feeding component and the second feeding component can simultaneously provide the first positive electrode sheet and the second positive electrode sheet, thereby improving the feeding efficiency. The composite mechanism includes a first composite roller group and a second composite roller group, which enables the second diaphragm and the first and second positive electrode sheets on the second diaphragm to form a composite sheet body. The composite sheet body is conveyed to the winding mechanism, which improves the feeding speed of the incoming material into the winding mechanism and improves the winding efficiency. At the same time, it also improves the alignment accuracy between the positive electrode sheet and the second diaphragm, and solves the problems of misalignment, wrinkling and uneven stacking of the positive electrode sheet under high-speed winding.

[0046] In some embodiments, the first feeding assembly includes a positive electrode sheet feeding assembly, a first cutting member, and a first adsorption belt arranged sequentially. The first adsorption belt is disposed between the first cutting member and the first composite roller group. The first cutting member is used to cut the positive electrode sheet released by the positive electrode sheet feeding assembly into a first positive electrode sheet. The first adsorption belt is used to adsorb the first positive electrode sheet and transfer it to the first composite roller group. The first composite roller group includes a first composite roller and a second composite roller arranged opposite to each other. The first composite roller has an atmospheric pressure zone and a negative pressure zone distributed along its circumference. The atmospheric pressure zone and the negative pressure zone alternately convey the first positive electrode sheet. The negative pressure zone is used to adsorb the head of the first positive electrode sheet.

[0047] By adopting the above technical solution, the winding equipment can improve the transfer accuracy of the first positive electrode sheet, thereby improving the alignment accuracy of the electrode sheet in the electrode assembly.

[0048] In some embodiments, the winding apparatus further includes a buffer mechanism disposed between the second composite roller group and the first composite roller group. The buffer mechanism buffers the second positive electrode sheet and the second separator after composite connection. The buffer mechanism is configured to maintain the rate at which the second positive electrode sheet is fed into the winding mechanism by releasing the internally buffered second positive electrode sheet and the second separator.

[0049] By adopting the above technical solution, the buffer mechanism can maintain the rate at which the second positive electrode is fed into the winding mechanism by releasing the second positive electrode and the second diaphragm that are internally buffered, thereby reducing the impact of other operations of the winding equipment on the transmission speed and effectively improving the production rate of the electrode assembly.

[0050] In some embodiments, the second feeding mechanism includes a negative electrode sheet feeding assembly, a third cutting member, and a second adsorption belt arranged sequentially. The third cutting member is used to cut the negative electrode sheet released by the negative electrode sheet feeding assembly. The second adsorption belt is disposed between the third cutting member and the first adhesive applicator. The second adsorption belt is used to adsorb and convey the negative electrode sheet.

[0051] By adopting the above technical solution, the second adsorption belt can transport the cut negative electrode sheet to the adhesive bonding mechanism, preventing the membrane from lifting or shifting during the transport process and improving the yield of adhesive bonding of the negative electrode sheet.

[0052] In some embodiments, the first feeding mechanism is further configured to cut the positive electrode sheet into at least one third positive electrode sheet, the third positive electrode sheet being wound around the outer ring of the second positive electrode sheet.

[0053] By adopting the above technical solutions, the electrode assemblies produced by the winding equipment can flexibly combine the stacking part and the winding part, thereby improving space utilization and the energy density of the battery cell.

[0054] Thirdly, embodiments of this application also provide a battery device, which includes a battery cell as described above.

[0055] The beneficial effects of the embodiments of this application are as follows: The battery device provided in the embodiments of this application includes the battery cell as described above, thus the energy density of the battery device is high.

[0056] Fourthly, embodiments of this application also provide an electrical device, which includes a battery cell as described above, or a battery device as described above; the battery cell or battery device is used to provide electrical energy.

[0057] The beneficial effects of the embodiments of this application are as follows: The electrical equipment provided in the embodiments of this application includes the battery cell or the battery device as described above, thereby the electrical equipment has a high energy density. Attached Figure Description

[0058] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0059] Figure 1 This application provides structural schematic diagrams of vehicles for some embodiments; Figure 2 Exploded views of battery devices provided in some embodiments of this application; Figure 3 This is an exploded structural diagram of a battery cell provided in some embodiments of this application; Figure 4 This is a schematic diagram of the structure of an electrode assembly provided in some embodiments of this application; Figure 5 This is a schematic diagram of the structure of the electrode assembly and the winding needle provided in some embodiments of this application; Figure 6 This is a schematic diagram of the structure of an electrode assembly provided in other embodiments of this application; Figure 7A schematic diagram of the structure of two electrode assemblies in a battery cell provided in some embodiments of this application; Figure 8 This is a schematic diagram of the structure of a winding device provided in some embodiments of this application; Figure 9 (a) is a schematic diagram of the structure of the first adhesive bonding mechanism, positive electrode, negative electrode, first diaphragm and second diaphragm provided in some embodiments of this application before the adhesive is attached; Figure 9 (b) is a schematic diagram of the structure of the first adhesive bonding mechanism, positive electrode, negative electrode, first diaphragm and second diaphragm after being attached to the adhesive component according to some embodiments of this application; Figure 10 This is a schematic diagram of the structure of the second feeding mechanism provided in some embodiments of this application; Figure 11 This is a schematic diagram of the structure of a first feeding assembly provided in some embodiments of this application.

[0060] The following are the labeling elements in the figure: 1000, Vehicle; 100, Battery unit; 1001, Controller; 1002, Motor; 10. Housing; 11. First housing; 12. Second housing; 20. Battery cell; 201. Shell; 21. End cap; 21a. Electrode terminal; 22. Housing; 23. Electrode assembly; 23a. Straight area; 23b. Corner area; 230a. Tab; 231. Positive electrode; 2311. Second positive electrode; 23111. Straight positive portion; 23112. Bent positive portion; 2312. First positive electrode; 2313. Third positive electrode; 232. Negative electrode; 2321. Straight negative portion; 23211. First straight negative portion; 23212. Second straight negative portion; 2322. Bent negative portion; 233. Separator; 2331. First separator; 2332. Second separator; 235. Adhesive; 236. Composite sheet; 200. Winding equipment; 210. First feeding mechanism; 211. First feeding assembly; 2111. First positive electrode sheet feeding assembly; 2112. First cutting component; 2113. First suction belt; 212. Second feeding assembly; 2121. Second positive electrode sheet feeding assembly; 2122. Second cutting component; 220. Second feeding mechanism; 221. Negative electrode sheet feeding assembly; 222. Third cutting component; 223. Second suction belt; 230. Third feeding mechanism; 2301. First diaphragm feeding assembly; 2302. Second diaphragm feeding assembly; 250. Winding mechanism; 251. Winding needle; 260. Composite mechanism; 261. First composite roller group; 2611. First composite roller; 2611a. Normal pressure zone; 2611b. Negative pressure zone; 2612. Second composite roller; 262. Second composite roller group; 270. Buffer mechanism; 280. First adhesive application mechanism; 281. First adhesive application roller; 282. Second adhesive application roller; 290. Second adhesive application mechanism. Detailed Implementation

[0061] The embodiments of this application are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0062] In the description of this application, it should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0063] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0064] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction 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.

[0065] Currently, judging from market trends, the application of power battery devices is becoming increasingly widespread. Power batteries are not only used in energy storage systems such as hydropower, thermal power, wind power, and solar power plants, but also widely applied in electric vehicles such as electric bicycles, electric motorcycles, and electric cars, as well as in industrial equipment and aerospace. With the continuous expansion of power battery applications, market demand is also constantly increasing.

[0066] Electrode assemblies typically include a positive electrode, a negative electrode, and a separator wound together. However, in related technologies, the innermost electrode layer is often not effectively utilized, affecting the energy density of the individual battery cell. In the innermost circle of the electrode assembly, there is often a problem of negative electrode layers facing each other, preventing some of the innermost negative electrode layers from participating in the electrochemical reaction.

[0067] In view of this, in order to improve the energy density of a single battery cell, a battery cell is proposed. The battery cell includes an electrode assembly, which includes a positive electrode sheet, a separator, and a negative electrode sheet wound together. The positive electrode sheet is configured as a first positive electrode sheet and a second positive electrode sheet spaced apart along the winding direction. The second positive electrode sheet includes a plurality of alternately arranged straight positive electrode portions and bent positive electrode portions. The negative electrode sheet includes a plurality of alternately arranged straight negative electrode portions and a plurality of bent negative electrode portions. The plurality of straight negative electrode portions include a first straight negative electrode portion and a second straight negative electrode portion. The first negative electrode straight section is located at the winding start end closest to the negative electrode sheet along the winding direction. The second negative electrode straight section is connected to the first negative electrode straight section through a negative electrode bend. At least one second positive electrode sheet is located between the first and second negative electrode straight sections. In this way, the innermost negative electrode sheet can transfer ions with the first positive electrode sheet, allowing both the innermost positive and negative electrodes to participate in the electrochemical reaction. This solves the problem of the innermost part of the electrode sheet not being effectively utilized, improving the utilization rate of the electrode active material and increasing the energy density of the battery cell. Furthermore, the electrode assembly also includes an adhesive component. The winding start end of the negative electrode sheet is adhered to the separator through the adhesive component. Thus, during the electrode assembly manufacturing process, the negative electrode sheet can enter the winding mechanism along with the separator for winding, significantly improving the winding feeding speed and winding efficiency, and increasing the manufacturing efficiency of the battery cell.

[0068] The battery device disclosed in this application can be used in electrical devices that use the battery device as a power source or in various energy storage systems that use the battery device as an energy storage element. The electrical devices can be, but are not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, etc. Among them, electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc., and spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0069] For ease of explanation, the following embodiments will be described using a vehicle 1000 as an example of an electrical device according to an embodiment of this application.

[0070] 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. The vehicle 1000 can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. A battery device 100 is provided inside the vehicle 1000, and the battery device 100 can 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. The vehicle 1000 may also include a controller 1001 and a motor 1002. The controller 1001 is used to control the battery device 100 to supply power to the motor 1002, for example, to meet the power needs of the vehicle 1000 during starting, navigation, and driving.

[0071] 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.

[0072] 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 mentioned in the embodiments of this application may include one or more battery cell assemblies for providing voltage and capacity. The battery cell assembly may include a plurality of battery cells 20, which are connected in series, parallel, or mixed connection via a busbar.

[0073] In some embodiments, the battery cell assembly is typically formed by arranging a plurality of battery cells 20.

[0074] As an example, the battery cell assembly can be a battery module, which is formed by arranging and fixing multiple battery cells 20 into a single module. As an example, the battery module can be formed by bundling multiple battery cells 20 together with cable ties.

[0075] In some embodiments, the battery device 100 may be a battery pack, which includes a housing 10 and one or more battery cell assemblies housed in the housing 10.

[0076] As an example, the battery cell assembly can be a battery module, and the battery cell assembly can be housed in the housing 10 by fixing the battery module in the housing 10.

[0077] As an example, the battery cell assembly can also be housed in the housing 10 by directly fixing multiple battery cells 20 to the housing 10.

[0078] As an example, the housing 10 may include a first housing 11 and a second housing 12. The first housing 11 and the second housing 12 are fastened together to form a closed space inside the housing 10 to house the battery cell assembly. Here, "closed" refers to covering or closing, and can be either sealed or unsealed. The first housing 11 may be a top cover or a bottom plate.

[0079] As an example, the housing 10 may include a top cover, a frame, and a bottom plate. The top cover and the bottom plate are respectively connected to the frame, so that the interior of the housing 10 forms an enclosed space to accommodate the battery cell assembly.

[0080] In some embodiments, the housing 10 may be part of the chassis structure of the vehicle 1000. For example, a portion of the housing 10 may be at least a portion of the floor of the vehicle 1000, or a portion of the housing 10 may be at least a portion of the crossbeams and longitudinal beams of the vehicle 1000.

[0081] The technical solutions described in the embodiments of this application are applicable to various electrical devices that use battery cells 20, 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.

[0082] In this embodiment of the application, the battery cell 20 can be a secondary battery, which refers to a battery cell 20 that can be used again after being discharged by recharging to activate the active materials.

[0083] The battery cell 20 can be a lithium-ion battery, sodium-ion battery, sodium-lithium-ion battery, lithium metal battery, sodium metal battery, lithium-sulfur battery, magnesium-ion battery, nickel-metal hydride battery, nickel-cadmium battery, lead-acid battery, etc., and the embodiments of this application are not limited to this.

[0084] Please refer to Figure 3 , Figure 3 This is an exploded structural diagram of a battery cell 20 provided in some embodiments of this application. The battery cell 20 refers to the smallest unit constituting the battery device 100. For example... Figure 3 The battery cell 20 includes a housing 201, an electrode assembly 23, and other functional components.

[0085] The outer casing 201 includes an end cap 21 and a housing 22. The end cap 21 is a component that covers the opening of the housing 22 to isolate the internal environment of the battery cell 20 from the external environment; the shape of the end cap 21 can be adapted to the shape of the housing 22 to fit it. Optionally, the end cap 21 can be made of a material with a certain hardness and strength (such as aluminum alloy), so that the end cap 21 is not easily deformed under pressure and impact, allowing the battery cell 20 to have higher structural strength and improved safety performance. Functional components such as electrode terminals 21a can be provided on the end cap 21. The electrode terminals 21a can be used for electrical connection with the electrode assembly 23 to output or input electrical energy to the battery cell 20. In some embodiments, the end cap 21 can also be provided with a pressure relief mechanism for releasing internal pressure when the internal pressure or temperature of the battery cell 20 reaches a threshold. The end cap 21 can also be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc. In some embodiments, an insulating element may be provided on the inner side of the end cap 21. The insulating element can be used to isolate the electrical connection components within the housing 22 from the end cap 21 to reduce the risk of short circuits. For example, the insulating element may be made of plastic, rubber, etc.

[0086] The housing 22 is a component used to cooperate with the end cap 21 to form the internal environment of the battery cell 20. This internal environment can accommodate the electrode assembly 23, electrolyte, and other components. The housing 22 and the end cap 21 can be independent components. An opening can be provided on the housing 22, and the end cap 21 closes the opening to form the internal environment of the battery cell 20. Alternatively, the end cap 21 and the housing 22 can be integrated. Specifically, the end cap 21 and the housing 22 can form a common connecting surface before other components are inserted into the housing. When it is necessary to encapsulate the interior of the housing 22, the end cap 21 closes the housing 22. The housing 22 can be of various shapes and sizes, such as cuboid, cylindrical, hexagonal prism, etc. Specifically, the shape of the housing 22 can be determined according to the specific shape and size of the electrode assembly 23. The housing 22 can be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc.

[0087] Electrode assembly 23 is the component in the battery cell 20 where the electrochemical reaction occurs. The casing 22 may contain one or more electrode assemblies 23. The electrode assembly 23 is mainly formed by winding or stacking positive and negative electrode sheets, and typically a separator 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 of the electrode assembly 23, while the portions of the positive and negative electrode sheets without active material each constitute a tab 230a. The positive and negative tabs may be located together at one end of the main body or separately at both ends of the main body. During the charging and discharging process of the battery device 100, the positive and negative active materials react with the electrolyte, and the tabs 230a connect to the electrode terminals 21a to form a current loop.

[0088] An embodiment of the first aspect of this application provides a battery cell 20. (Refer to...) Figure 3 and Figure 4 This application provides a battery cell 20, including a housing 201 and an electrode assembly 23 disposed within the housing 201. The electrode assembly 23 includes a positive electrode 231, a separator 233, and a negative electrode 232 wound together. A separator 233 is disposed between the positive electrode 231 and the negative electrode 232. The positive electrode 231 includes a first positive electrode 2312 and a second positive electrode 2311 spaced apart along the winding direction of the electrode assembly. The second positive electrode 2311 includes a plurality of alternating positive electrode straight portions 23111 and positive electrode bent portions 23112. The negative electrode 232 includes a plurality of alternating negative electrode straight portions 2321 and negative electrode bent portions 2322. The straight portion 2321 includes a first negative electrode straight portion 23211 and a second negative electrode straight portion 23212. Among the multiple negative electrode straight portions 2321, the one closest to the winding start end of the negative electrode sheet 232 along the winding direction is the first negative electrode straight portion 23211. The second negative electrode straight portion 23212 is connected to the first negative electrode straight portion 23211 through the negative electrode bending portion 2322. Along the thickness direction of the electrode assembly 23, at least one first positive electrode sheet 2312 is located between the first negative electrode straight portion 23211 and the second negative electrode straight portion 23212. The electrode assembly 23 also includes an adhesive 235, and the winding start end of the negative electrode sheet 232 is attached to the diaphragm 233 through the adhesive 235.

[0089] The positive electrode 231 (also called the cathode) includes a positive current collector and a positive active material disposed on at least one surface of the positive current collector. Taking a lithium-ion battery cell 20 as an example, the material of the positive current collector can be aluminum, and the positive active material can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide, etc. The negative electrode 232 (also called the anode) includes a negative current collector and a negative active material disposed on at least one surface of the negative current collector. The material of the negative current collector can be copper, and the negative active material can be carbon or silicon, etc.

[0090] The diaphragm 233 is used to separate the positive electrode 231 and the negative electrode 232, so that the positive electrode 231 and the negative electrode 232 will not be short-circuited on opposite sides after winding; and the diaphragm 233 can facilitate the transfer and reaction of positive and negative ions. The material of the diaphragm 233 can be PP (polypropylene) or PE (polyethylene), etc.

[0091] The electrode assembly 23 is shaped into a flat structure, resulting in a flat region 23a and two corner regions 23b. The flat region 23a refers to the area where the positive electrode 231 and negative electrode 232 are shaped and pressed to form a flat shape, while the corner regions 23b refer to the areas where the positive electrode 231 and negative electrode 232 are shaped and pressed to form corners. It should be understood that corner regions 23b are formed on opposite sides of the flat region 23a.

[0092] The positive electrode 231 includes a first positive electrode 2312 and a second positive electrode 2311 spaced apart along the winding direction. That is, along the winding direction, the first positive electrode 2312 is located upstream of the second positive electrode 2311. During winding, the first positive electrode 2312 is wound first, and the second positive electrode 2311 is wound later. The number of first positive electrode 2312 can be one or more, and the number of second positive electrode 2311 can also be one or more.

[0093] The first positive electrode 2312 may be a flat electrode sheet, or it may include a flat electrode sheet and at least a partially curved sheet. It should be understood that the length of the first positive electrode 2312 is shorter than the length of the electrode assembly 23. That is, when the first positive electrode 2312 is wound into the electrode assembly 23, each first positive electrode 2312 may be located only in one layer of the winding structure (e.g., the innermost layer, the second innermost layer, or any middle layer of the winding structure), or each first positive electrode 2312 may be wound in the winding structure to form a half-turn, a full turn, or a half-turn, etc. Both the first positive electrode 2312 and the second positive electrode 2311 are cut from positive electrode sheets and may include a positive current collector and a positive active material (e.g., positive ions) coated on both sides of the positive current collector.

[0094] The second positive electrode 2311 includes a plurality of alternately arranged positive electrode straight portions 23111 and positive electrode bent portions 23112, each positive electrode bent portion 23112 connecting two adjacent positive electrode straight portions 23111. The second positive electrode 2311 can be wound into a multi-turn structure; for example, the second positive electrode 2311 can extend from after the first positive electrode 2312 to the winding end of the electrode assembly 23.

[0095] The negative electrode 232 is wound into multiple turns. The negative electrode 232 includes multiple alternating negative electrode straight portions 2321 and negative electrode bent portions 2322, wherein the negative electrode bent portions 2322 are connected between two negative electrode straight portions 2321.

[0096] The plurality of negative electrode straight portions 2321 include a first negative electrode straight portion 23211 and a second negative electrode straight portion 23212. According to the winding sequence, the first negative electrode straight portion 23211 is the negative electrode straight portion 2321 closest to the starting end of the winding along the winding direction of the negative electrode sheet. The second negative electrode straight portion 23212 is connected to the first negative electrode straight portion 23211 via a negative electrode bend 2322. The first negative electrode straight portion 23211 and the second negative electrode straight portion 23212 are located on opposite sides of the winding axis of the electrode assembly. It can be understood that the first negative electrode straight portion 23211 and the second negative electrode straight portion 23212 are located at the innermost circle of the negative electrode sheet.

[0097] The starting end of the winding of the negative electrode 232 refers to the starting point of the winding of the negative electrode 232 when the negative electrode 232 is wound to form an electrode assembly. After the winding is completed, the starting end of the winding is located at the innermost side of the electrode assembly 23 relative to other parts of the negative electrode 232.

[0098] At least one first positive electrode 2312 is located between the first negative electrode straight portion 23211 and the second negative electrode straight portion 23212. It can be understood that the first positive electrode 2312 is separated from the first negative electrode straight portion 23211 and the second negative electrode straight portion 23212 by a separator 233.

[0099] In this way, the innermost straight portion 2321 of the negative electrode 232 and the first positive electrode 2312 can be used for the transfer and reaction of positive and negative ions, solving the problem that the innermost part of the negative electrode cannot be effectively utilized in related technologies.

[0100] The electrode assembly 23 also includes an adhesive 235, through which the starting end of the winding of the negative electrode 232 is adhered to the diaphragm 233. The starting end of the winding of the negative electrode 232 can be the end point of the first negative electrode straight portion 23211, in which case the first negative electrode straight portion 23211 is adhered to the diaphragm 233 via the adhesive 235. Optionally, the negative electrode 232 can also include a negative electrode bent portion located upstream of the first negative electrode straight portion 23211, in which case the negative electrode bent portion 2322 can be adhered to the diaphragm 233 via the adhesive 235.

[0101] The adhesive 235 may be an adhesive tape. Optionally, the thickness of the adhesive 235 may be from 3 micrometers to 2 millimeters, and the thickness of the adhesive 235 may be designed according to factors such as the size and energy density of the electrode assembly 23.

[0102] During winding, the head of the separator 233 enters the winding needle 251 first, and the starting end of the negative electrode 232 is attached to the separator 233 via the adhesive 235. In this way, during winding, the negative electrode 232 can enter the winding needle 251 along with the separator 233. Compared to using clamps to separately feed the negative electrode 232 and the separator 233 into the winding needle 251, this significantly improves the winding feeding speed and winding efficiency. Furthermore, having the starting end of the negative electrode 232 enter the winding needle along with the separator 233 also reduces the length of the unwound separator, further increasing the energy density of the electrode assembly. Meanwhile, since the starting end of the winding of the negative electrode 232 is fixed to the diaphragm 233 by the adhesive 235, the relative sliding or misalignment between the starting end of the winding of the negative electrode 232 and the diaphragm 233 is eliminated, which improves the consistency of the product and makes it less likely to cause problems such as uneven winding and uneven edges due to initial misalignment. It also reduces the risk that the head of the negative electrode 232 will bounce off or shift from the winding structure during the winding process.

[0103] In the battery cell 20 provided in this application embodiment, the first positive electrode 2312 is located between the first negative electrode straight portion 23211 and the second negative electrode straight portion 23212, so that both the innermost positive and negative electrode sheets can participate in the electrochemical reaction, solving the problem that the innermost part of the negative electrode sheet cannot be effectively utilized, improving the utilization rate of the electrode active material, and improving the energy density of the battery cell 20; at the same time, the winding start end of the negative electrode sheet 232 is attached to the separator 233 by the adhesive 235, which improves the winding feeding speed and winding efficiency of the electrode assembly 23, and improves the alignment accuracy between the negative electrode sheet 232 and the separator 233, thereby improving the manufacturing efficiency and yield of the electrode assembly 23.

[0104] In some embodiments, there are multiple first positive electrode plates 2312, and the multiple first positive electrode plates 2312 are arranged sequentially at intervals along the winding direction. Along the thickness direction of the electrode assembly 23 (Z direction in the figure), each first positive electrode plate 2312 is located between two adjacent negative electrode straight portions 2321.

[0105] For example, such as Figure 4 As shown, there are three first positive electrode plates 2312. One first positive electrode plate 2312 is located in the innermost ring of the electrode assembly 23, and the other two first positive electrode plates 2312 are located in the second inner ring and the third ring, respectively. It can be understood that the number of first positive electrode plates 2312 can also be two or more.

[0106] After the electrode assembly 23 is wound and shaped, the bending angle of the inner ring is relatively large. By setting the number of first positive electrode sheets 2312 to multiple, the multiple first positive electrode sheets 2312 can be distributed in multiple turns of the inner ring, which improves the problem of the positive electrode sheet 231 breaking and shedding powder in the inner ring due to the large bending degree.

[0107] In other embodiments, the number of first positive electrode plates 2312 may also be one, in order to improve the energy density of the electrode assembly.

[0108] Please refer to Figure 4 and Figure 6 In some embodiments, the projection direction of the electrode assembly 23 is the thickness direction, and the projections of the first negative electrode flat portion 23211 and the second negative electrode flat portion 23212 respectively cover the first positive electrode sheet 2312.

[0109] The thickness direction (Z direction in the figure) of the electrode assembly 23 is the stacking direction of the multiple positive electrode straight portions 23111 and the stacking direction of the multiple negative electrode straight portions 2321.

[0110] In this embodiment, the first positive electrode 2312 is entirely located in the flat region 23a, that is, the first positive electrode 2312 is entirely located between the first negative electrode flat portion 23211 and the second negative electrode flat portion 23212 and does not extend into the corner region 23b, so that the first positive electrode 2312 can be completely covered by the projection of the adjacent negative electrode flat portion 2321.

[0111] In this embodiment, the projections of the first negative electrode flat portion 23211 and the second negative electrode flat portion 23212 respectively cover the first positive electrode sheet 2312 to meet the requirement of the electrode assembly 23 for excessive design of negative electrode active material. It can be understood that for lithium-ion batteries, during the first charge, the reaction between the negative electrode and the electrolyte forms a solid electrolyte interface (SEI) film on the negative electrode surface. The SEI film has the characteristics of an ion conductor and an electronic insulator, allowing lithium ions to pass through while isolating electrons. The SEI film is fundamental to the operation of lithium-ion batteries. In actual production, the negative electrode needs to react with the electrolyte during the formation of the SEI film, and the SEI film will rupture and repair during battery operation. Therefore, when designing the battery, it is necessary to excessively design the negative electrode capacity to provide sufficient negative electrode capacity and reaction to form the SEI film, while ensuring that the negative electrode capacity meets the lithium-ion battery insertion requirements.

[0112] By adopting the above technical solution, the first positive electrode 2312 can be completely covered by the projection of the adjacent negative electrode straight portion 2321, so as to meet the requirement of the electrode assembly 23 for the over-design of negative electrode active material.

[0113] In some embodiments, the first positive electrode 2312 and the first negative electrode straight portion 23211 are separated by a membrane 233.

[0114] The diaphragm 233 is wound in multiple turns. The diaphragm 233 includes a first diaphragm 2331 and a second diaphragm 2332 that are stacked and spaced apart. The portion of the first diaphragm 2331 or the second diaphragm 2332 within the straight region 23a of each turn is a single layer of diaphragm.

[0115] Only one membrane 233 is provided between the first positive electrode 2312 and the first negative electrode straight portion 23211, and ions are transferred between the first positive electrode 2312 and the first negative electrode straight portion 23211 through the membrane 233.

[0116] By setting only one layer of separator 233 between the first positive electrode 2312 and the negative electrode 232, the problem of redundant winding of the separator is improved, the spatial layout is optimized, and the energy density of the battery cell 20 is further improved.

[0117] In other embodiments, multiple layers of separators may also be provided between the first positive electrode 2312 and the first negative electrode straight portion 23211.

[0118] Optionally, the first positive electrode 2312 is located only in the flat region 23a, which solves the problem that the part of the positive electrode 231 located in the inner circle is prone to breakage and powder shedding in the corner region 23b due to the large degree of bending, thus improving the stability of the battery cell 20.

[0119] Please refer to Figure 4 and Figure 5 In some embodiments, along the winding direction, the first negative electrode straight portion 23211 is located downstream of the innermost first positive electrode piece 2312.

[0120] The first negative electrode straight portion 23211 is located at the starting end of the winding of the negative electrode sheet 232, which refers to the end at which the negative electrode sheet 232 begins to be wound. The number of first positive electrode sheets 2312 can be one or more, but only one first positive electrode sheet 2312 is located in the innermost ring of the electrode assembly 23.

[0121] Optionally, in the innermost ring of the electrode assembly 23, the length of the winding start end of the first separator 2331 extending beyond the winding start end of the first positive electrode 2312 is less than the length of the flat region 23a, and the length of the winding start end of the second separator 2332 extending beyond the winding start end of the first positive electrode 2312 is also less than the length of the flat region 23a. That is, the electrode assembly 23 does not have the problem of redundant winding of the separator multiple times.

[0122] The electrode assembly 23 can be wound using a winding device 200, which includes a winding needle 251. During winding, the first positive electrode 2312 enters the winding needle 251 first, followed by the negative electrode 232. The negative electrode 232 can be directly attached to the surface of the winding needle 251. The first positive electrode 2312 and the negative electrode 232 can be arranged opposite each other in the innermost ring of the electrode assembly 23. After the electrode assembly 23 is shaped into a flat structure, the portions of the first positive electrode 2312 and the negative electrode 232 located in the flat region 23a are located on both sides of the winding axis and separated by a diaphragm 233.

[0123] By adopting the above technical solution, the first negative electrode straight portion 23211 is located downstream of the innermost first positive electrode 2312. The first positive electrode 2312 and the negative electrode 232 can be wound one after the other, so that the negative electrode 232 can be arranged opposite to the first positive electrode 2312 in the innermost circle of the electrode assembly 23, and the first positive electrode 2312 and the negative electrode 232 are separated only by a separator 233, which improves the energy density of the battery cell 20.

[0124] In some embodiments, along the thickness direction of the electrode assembly 23, the adhesive 235 is offset from the innermost first positive electrode 2312.

[0125] The thickness direction of the electrode assembly 23 is perpendicular to the winding direction and is the stacking direction of the positive electrode 231 and the negative electrode 232 in the flat region 23a. The adhesive 235 is offset from the innermost first positive electrode 2312, that is, along the thickness direction of the electrode assembly 23, the orthographic projection of the adhesive 235 does not coincide with the orthographic projection of the first positive electrode 2312.

[0126] For example, the adhesive 235 is located in the corner region 23b, so that the adhesive 235 is offset from the first positive electrode 2312 located in the straight region 23a.

[0127] For example, the adhesive 235 may also be located at least partially in the flat region 23a, and the length of the innermost first positive electrode 2312 may be less than the length of the flat region 23a, thus allowing the adhesive 235 to be staggered from the first positive electrode 2312.

[0128] By offsetting the adhesive 235 from the first positive electrode 2312, the adhesive 235 can avoid the innermost first positive electrode 2312, and the first positive electrode 2312 will not be over-voltaged or damaged due to the adhesive 235, thus improving the stability of the battery cell 20.

[0129] In some embodiments, the electrode assembly 23 includes a flat region 23a and corner regions 23b located at both ends of the flat region 23a. The positive electrode flat portion and the negative electrode flat portion are located in the flat region 23a, and the positive electrode bent portion and the negative electrode bent portion are located in the corner region 23b. The adhesive 235 is located in the corner region 23b.

[0130] Since the first positive electrode 2312 is located in the flat region 23a, by placing the adhesive 235 in the corner region 23b, the adhesive can effectively avoid the first positive electrode 2312, reducing the risk of overvoltage of the positive electrode 231.

[0131] Please refer to Figures 4 to 6 , Figure 9 In some embodiments, there are multiple first positive electrode plates 2312, and the multiple first positive electrode plates 2312 are arranged sequentially at intervals, with each first positive electrode plate 2312 located between two adjacent negative electrode straight portions 2321; along the winding direction, the adhesive 235 is located between the innermost first positive electrode plate 2312 and the next innermost first positive electrode plate 2312.

[0132] Before the positive electrode 231, negative electrode 232, and separator 233 enter the winding needle 251, the adhesive 235 is first attached to the separator 233 at the position corresponding to the gap between the two first positive electrode 2312. In this way, after winding, the adhesive 235 can be located in the corner area 23b and the first positive electrode 2312 can be located in the straight area 23a.

[0133] Thus, the adhesive 235 can fix the starting end of the negative electrode 232 to the separator 233 and position it between the two first positive electrodes 2312. During the winding process, after the first positive electrode 2312 is conveyed to the winding needle 251, the separator 233 carries the negative electrode 232 to the winding needle 251. This achieves a relative arrangement between the negative electrode 232 and the first positive electrode 2312 in the innermost ring, while also allowing the adhesive 235 to avoid the first positive electrode 2312, reducing the risk of brittle fracture and powder shedding of the inner positive electrode 231 due to overvoltage. Therefore, the structure of the electrode assembly 23 described above can improve the energy density and winding efficiency of the battery cell 20, and also enhance the stability of the battery cell 20.

[0134] In some other embodiments, there is one first positive electrode 2312; along the winding direction, the adhesive 235 is located between the first positive electrode 2312 and the second positive electrode 2311.

[0135] When there is only one first positive electrode 2312, the adhesive 235 is located between the first positive electrode 2312 and the second positive electrode 2311; please refer to... Figure 9Before the winding needle 251, the head of the negative electrode 232 is bonded to the separator 233 by the adhesive 235, so that the adhesive 235 is located between the first positive electrode 2312 and the second positive electrode 2311. In this way, after winding, the adhesive 235 can be located between the first positive electrode 2312 and the second positive electrode 2311, the adhesive 235 can avoid the first positive electrode 2312 and the second positive electrode 2311, and the negative electrode 232 can be arranged opposite to the first positive electrode 2312 and the second positive electrode 2311 to improve energy density.

[0136] Thus, the number of first positive electrode plates 2312 can be one. By placing one first positive electrode plate 2312 in the innermost ring of the electrode assembly 23, an electrochemical reaction can be generated between the first positive electrode plate 2312 and the negative electrode plate 232 to solve the problem of waste of inner ring electrode plates. At the same time, the first positive electrode plate 2312 and the second positive electrode plate 2311 are arranged alternately, and the adhesive 235 is located in the corner area 23b. The adhesive 235 is located between the first positive electrode plate 2312 and the second positive electrode plate 2311, which can also reduce the risk of the inner ring positive electrode plate 231 becoming brittle and cracking or shedding powder due to overvoltage. The electrode assembly 23 of the above embodiment can also improve the energy density and winding efficiency of the battery cell 20, and improve the stability of the battery cell 20.

[0137] Please refer to Figure 6 In some embodiments, along the thickness direction of the electrode assembly 23 ( Figure 6 In the Z-direction, the first positive electrode 2312 of the innermost ring is offset from the adhesive 235, and the length of the first positive electrode 2312 of the innermost ring is less than the length of the straight region 23a.

[0138] When there are multiple first positive electrode plates 2312, the length of the innermost first positive electrode plate 2312 is less than the length of the other first positive electrode plates 2312.

[0139] Since the adhesive 235 is located in the innermost ring, the length of the first positive electrode 2312 in the innermost ring can be set to be shorter, so that the end of the first positive electrode 2312 close to the adhesive 235 can also effectively avoid the adhesive 235, further reducing the risk of overvoltage of the first positive electrode 2312 due to the adhesive 235.

[0140] In some embodiments, the diaphragm 233 includes a first diaphragm 2331 and a second diaphragm 2332. The first diaphragm 2331, the positive electrode 231, the second diaphragm 2332 and the negative electrode 232 are stacked and wound in sequence. The starting end of the winding of the negative electrode 232 is attached to the second diaphragm 2332 by an adhesive 235.

[0141] When winding the electrode assembly 23, according to the above stacking order, the negative electrode 232 is disposed on one side of the first separator 2331, the positive electrode 231, and the second separator 2332, which can easily attach the negative electrode 232 to the second separator 2332 by the adhesive 235. In the wound electrode assembly 23, the positive electrode 231 and the negative electrode 232 are separated by the first separator 2331 and the second separator 2332, making it difficult for the positive electrode 231 and the negative electrode 232 to come into contact and cause a short circuit, thereby improving the safety of the battery cell 20 composed of the electrode assembly 23.

[0142] In some embodiments, the first positive electrode 2312 and the first separator 2331 are rolled together to form a composite sheet 236, or the first positive electrode 2312 and the second separator 2332 are rolled together to form a composite sheet 236.

[0143] For example, such as Figure 5 , Figure 8 , Figure 9 As shown, in some embodiments, the first diaphragm 2331 is the upper diaphragm, and the second diaphragm 2332 is the lower diaphragm. Before entering the winding needle 251, the first diaphragm 2331 is located above the second diaphragm 2332. The first positive electrode 2312 and the second diaphragm 2332 are rolled together to form a composite sheet 236. In addition, since the winding start end of the negative electrode 232 is attached to the second diaphragm 2332 through the adhesive 235, both the first positive electrode 2312 and the negative electrode 232 can enter the winding needle together with the second diaphragm 2332, which significantly improves the alignment accuracy and winding feed speed, and improves the winding efficiency.

[0144] The number of first positive electrode plates 2312 can be one or more. When there are multiple first positive electrode plates 2312, the multiple first positive electrode plates 2312 are sequentially connected to the first separator 2331.

[0145] In another embodiment, the first positive electrode 2312 may also be combined with the first separator 2331 to form a composite sheet 236.

[0146] By adopting the above technical solution, the first positive electrode 2312 can be combined with the first separator 2331 or the second separator 2332, which improves the alignment accuracy between the first positive electrode 2312 and the separator. Furthermore, the first positive electrode 2312 can enter the winding needle 251 together with the first separator 2331 or the second separator 2332. On the one hand, the first positive electrode 2312 is less likely to detach or wrinkle when entering the winding needle 251. On the other hand, it improves the winding feeding speed and winding efficiency. Moreover, the fact that the first positive electrode 2312 can enter the winding needle 251 together with the first separator 2331 or the second separator 2332 can also reduce the length of redundant winding at the head of the separator.

[0147] In some embodiments, the first positive electrode 2312 and the second positive electrode 2311 are both combined with the second separator 2332 by roll forming to form a composite sheet 236.

[0148] For example, such as Figure 5 , Figure 8 , Figure 9 As shown, the winding equipment 200 includes a first feeding assembly 211 and a second feeding assembly 212. Both the first feeding assembly 211 and the second feeding assembly 212 are used to release the positive electrode sheet 231. The first feeding assembly 211 is also used to cut the positive electrode sheet 231 to form the first positive electrode sheet 2312. The winding equipment 200 also includes a first composite roller group 261 and a second composite roller group 262. The first positive electrode sheet 2312 and the second diaphragm 2332 are rolled together by the first composite roller group 261, and the second positive electrode sheet 2311 and the second diaphragm 2332 are rolled together by the second composite roller group 262 to form a composite sheet body 236. When entering the winding needle 251, the first diaphragm 2331, the composite sheet body 236 and the negative electrode sheet 232 are stacked in sequence.

[0149] In this embodiment, both the first positive electrode 2312 and the second positive electrode 2311 are composited with the second separator 2332, achieving pre-composite bonding of the positive electrode 231 and the second separator 2332. This improves the feeding speed of the incoming winding needle 251 and the winding efficiency. At the same time, it also improves the alignment accuracy of the positive electrode 231 and the second separator 2332, solving the problems of misalignment, wrinkling, and uneven stacking of the positive electrode 231 under high-speed winding.

[0150] Please refer to Figure 6 , Figure 7 In some embodiments, the positive electrode 231 further includes at least one third positive electrode 2313, which is spaced apart from the second positive electrode 2311 and is stacked on the side of the positive electrode straight portion 23111 away from the winding center of the electrode assembly 23.

[0151] like Figure 6 As shown, along the winding direction, the positive electrode 231 includes one or more first positive electrode 2312, a second positive electrode 2311, and one or more third positive electrode 2313, with the third positive electrode 2313 located on the outer ring of the second positive electrode 2311.

[0152] like Figure 3 and Figure 7As shown, two electrode assemblies 23 can be provided in the battery cell 20. The structures of the two electrode assemblies 23 can be the same or different. For example, one electrode assembly 23 includes one or more first positive electrode plates 2312, second positive electrode plates 2311 and third positive electrode plates 2313, and the other electrode assembly 23 includes one or more first positive electrode plates 2312 and second positive electrode plates 2311.

[0153] The electrode assembly 23 provided in this application embodiment can flexibly combine the stacked portion and the winding portion. By setting a third positive electrode 2313 on the outer ring of the second positive electrode 2311, the third positive electrode 2313 can fill the arc-shaped outer space naturally formed by the winding structure, thereby improving the space utilization and the energy density of the battery cell 20. The third positive electrode 2313 avoids the corner area 23b, reducing the risk of electrode breakage and short circuit of the battery cell 20 caused by external forces (such as collisions and compression), thereby improving the reliability of the battery cell 20.

[0154] Please refer to Figures 3 to 7 Some embodiments of this application provide a battery cell 20, including a housing 201 and an electrode assembly 23 disposed within the housing 201. The electrode assembly 23 includes a first separator 2331, a positive electrode 231, a second separator 2332, and a negative electrode 232 that are stacked and wound in sequence. The electrode assembly 23 also includes an adhesive 235, and the starting end of the winding of the negative electrode 232 is attached to the second separator 2332 through the adhesive 235. The positive electrode 231 includes a first positive electrode 2312 and a second positive electrode 2311 spaced apart along the winding direction of the electrode assembly. The second positive electrode 2311 includes a plurality of alternating positive straight portions 23111 and positive bent portions 23112. The negative electrode 232 includes a plurality of alternating negative straight portions 2321 and negative bent portions 2322. The plurality of negative straight portions 2321 include a first negative straight portion 23211 and a second negative straight portion 23212. The first negative straight portion 23211 is the negative straight portion 2321 of the negative electrode 2322 closest to the winding start end along the winding direction. The first negative straight portion 23211 is connected to the second negative straight portion 23212 through the negative bent portion 2322. At least one first positive electrode 2312 is located between the first negative straight portion 23211 and the second negative straight portion 23212. Along the winding direction, the starting end of the winding of the negative electrode 232 is located downstream of the innermost first positive electrode 2312; the first positive electrode 2312 and the second positive electrode 2311 are both rolled together with the second separator 2332 to form a composite sheet 236. The battery cell 20 provided in this embodiment can effectively improve the energy density.

[0155] Please refer to Figures 4 to 11This application provides a winding device 200 for fabricating an electrode assembly 23. The winding device 200 includes a first feeding mechanism 210, a second feeding mechanism 220, a third feeding mechanism 230, a winding mechanism 250, and a first adhesive applicator 280. The first feeding mechanism 210 provides a positive electrode sheet 231 and cuts it to form a first positive electrode sheet 2312 and a second positive electrode sheet 2311. The second feeding mechanism 220 provides a negative electrode sheet 232. The third feeding mechanism 230 provides a separator 233. The winding mechanism 250 includes a winding needle 25. 1. The winding needle 251 is used to wind the positive electrode 231, the separator 233 and the negative electrode 232 into an electrode assembly 23. The first adhesive applicator 280 is used to convey the stacked positive electrode 231, separator 233 and negative electrode 232 to the winding mechanism 250 and to attach the adhesive 235 to the winding start end of the negative electrode 232 and the separator 233. In the innermost circle of the electrode assembly 23, the winding start ends of the first positive electrode 2312 and the negative electrode 232 are arranged opposite to each other on the winding needle 251.

[0156] The first feeding mechanism 210 is used to provide the positive electrode 231 and cut the positive electrode 231 to form a first positive electrode 2312 and a second positive electrode 2311. For example, the first feeding mechanism 210 includes a first feeding component 211 and a second feeding component 212. Both the first feeding component 211 and the second feeding component 212 are used to release the positive electrode 231. The first feeding component 211 cuts the positive electrode 231 to form the first positive electrode 2312, and the second feeding component 212 cuts the positive electrode 231 to form the second positive electrode 2311. In other embodiments, the first feeding mechanism 210 may also include only the first feeding component 211, which sequentially forms the first positive electrode 2312 and the second positive electrode 2311 through a cutting operation.

[0157] The first adhesive applicator 280 is located downstream of the first feeding mechanism 210, the second feeding mechanism 220, and the third feeding mechanism 230. It can receive the materials provided by the first feeding mechanism 210, the second feeding mechanism, and the third feeding mechanism 230. For example, the diaphragm 233 includes a first diaphragm 2331 and a second diaphragm 2332. The first diaphragm 2331, the positive electrode 231, the second diaphragm 2332, and the negative electrode 232 are stacked sequentially in the first adhesive applicator 280. That is, the first diaphragm 2331 is located on the top side of the positive electrode 231, the second diaphragm 2332 is located on the bottom side of the positive electrode 231, and the negative electrode 232 is located on the bottom side of the second diaphragm 2332, but it is not limited to this.

[0158] The first adhesive applicator 280 attaches the adhesive 235 to the winding start end of the negative electrode 232 and the separator 233, so that the winding start end of the negative electrode 232 can enter the winding mechanism 250 together with the separator 233. Compared with the method of separately conveying the negative electrode 232 and the separator 233 to the winding mechanism 250, the embodiment of this application can increase the feeding speed to the winding mechanism 250, significantly improve the winding efficiency, and at the same time improve the alignment accuracy of the negative electrode 232 and the separator, thereby improving the manufacturing yield of the electrode assembly.

[0159] The winding mechanism 250 is located downstream of the first adhesive applicator 280 and is used to wind the positive electrode 231, the diaphragm 233 and the negative electrode 232 along the winding direction to form the electrode assembly 23. The electrode assembly 23 includes a multi-turn electrode and a diaphragm structure.

[0160] On the winding needle 251, in the innermost ring of the electrode assembly 23, the first positive electrode 2312 and the negative electrode 232 are positioned opposite each other at their winding start ends. Thus, in the wound electrode assembly 23, the first positive electrode 2312 and the negative electrode 232 can be used for the transfer and reaction of positive and negative ions, solving the problem in related technologies where the innermost portion of the electrode cannot be effectively utilized.

[0161] The number of first positive electrode plates 2312 can be one or more. In the winding direction, multiple first positive electrode plates 2312 are arranged sequentially, and multiple first positive electrode plates 2312 are located upstream of the second positive electrode plate 2311.

[0162] The winding apparatus 200 provided in this application embodiment is capable of fabricating the electrode assembly 23 in the battery cell 20 provided in the first aspect. It is understood that after the electrode assembly 23 is wound into a wound structure, the electrode assembly 23 can be shaped into a flat shape to form a flat region 23a and corner regions 23b located at both ends of the flat region 23a, thus forming the electrode assembly 23 provided in the first aspect. In the innermost ring of the electrode assembly 23, the first positive electrode sheet 2312 is at least partially located in the flat region 23a.

[0163] In the innermost ring of the electrode assembly 23, the first positive electrode 2312 and the winding start end of the negative electrode 232 are arranged opposite each other. The first negative electrode straight portion 23211 is the negative electrode straight portion 2321 closest to the winding start end of the negative electrode 232. Thus, after the electrode assembly 23 is wound, the first positive electrode 2312 is located between the first negative electrode straight portion 23211 and the second negative electrode straight portion 23212.

[0164] The winding equipment 200 provided in this application embodiment includes a first feeding mechanism 210 for providing a positive electrode sheet 231, a second feeding mechanism 220 for providing a negative electrode sheet 232, a third feeding mechanism 230 for providing a separator 233, and a winding mechanism 250. The first feeding mechanism 210 can cut the positive electrode sheet 231 to form a first positive electrode sheet 2312 and a second positive electrode sheet 2311. In the innermost circle of the electrode assembly 23, the winding start ends of the first positive electrode sheet 2312 and the negative electrode sheet 232 are arranged opposite to each other on the winding needle 251. In this way, the innermost negative electrode sheet 232 and the first positive electrode sheet 2312 can transfer ions, so that both the positive and negative electrodes in the innermost circle can participate in the electrochemical reaction. This solves the problem that the innermost part of the negative electrode sheet cannot be effectively utilized, improves the utilization rate of the active material of the electrode sheet, and improves the energy density of the battery cell 20. Meanwhile, the first adhesive applicator 280 attaches the adhesive 235 to the winding start end of the negative electrode sheet 232 and the separator 233, thereby improving the winding efficiency and the manufacturing yield of the electrode assembly 23.

[0165] In some embodiments, only one separator 233 is provided between the first positive electrode 2312 and the negative electrode 232. There is no redundant winding separator at the head of the electrode assembly 23, which optimizes the spatial layout and improves the energy density of the battery cell 20.

[0166] In some embodiments, the first positive electrode 2312 is located in the flat region 23a. By placing the first positive electrode 2312 in the inner ring of the electrode assembly 23, the problem of the positive electrode 231 being prone to breakage and powder shedding due to the large bending degree of the inner ring is reduced, thereby improving the stability of the battery cell 20.

[0167] In some embodiments, the first adhesive applicator 280 includes a first adhesive applicator roller 281 and a second adhesive applicator roller 282 disposed opposite to each other. The first adhesive applicator roller 281 and the second adhesive applicator roller 282 are used to convey the stacked positive electrode sheet 231, the separator 233 and the negative electrode sheet 232. The second adhesive applicator roller 282 is used to attach the adhesive 235 to the winding start end of the negative electrode sheet 232 and the separator 233.

[0168] The first adhesive applicator 280 includes a first adhesive applicator roller 281 and a second adhesive applicator roller 282 arranged opposite to each other. The material provided by each feeding mechanism can be conveyed between the first adhesive applicator roller 281 and the second adhesive applicator roller 282. For example, the first adhesive applicator roller 281 and the second adhesive applicator roller 282 are arranged vertically, but it is not limited to this. As long as the positive electrode plate 231 can be attached to the second adhesive applicator roller 282, it is acceptable.

[0169] The second adhesive roller 282 is used to provide and attach the adhesive 235. For example, the adhesive 235 may be an adhesive paper with adhesive properties. The second adhesive roller 282 can attach the adhesive 235 to the winding start end of the negative electrode 232 and the separator 233, so that the winding start end of the negative electrode 232 (i.e. the head of the negative electrode 232) can enter the winding mechanism 250 together with the separator 233. Compared with the method of conveying the negative electrode 232 and the separator 233 to the winding mechanism 250 separately, the embodiment of this application can increase the feeding speed to the winding mechanism 250 and significantly improve the winding efficiency.

[0170] By adopting the above technical solution, the first adhesive applicator 280 can attach the adhesive 235 to the winding start end of the negative electrode sheet 232 and the separator 233. In this way, the negative electrode sheet 232 can enter the winding mechanism 250 together with the separator 233, thereby improving the winding feeding speed and winding efficiency.

[0171] Please refer to Figure 8 and Figure 9 In some embodiments, along the conveying direction of the first adhesive applicator 280, the starting end of the winding of the negative electrode 232 is located downstream of the first positive electrode 2312; wherein, there are multiple first positive electrode 2312s and the multiple first positive electrode 2312s are arranged sequentially at intervals, and the adhesive 235 is located between the first first positive electrode 2312 and the second first positive electrode 2312; or, there is only one first positive electrode 2312, and the adhesive 235 is located between the first positive electrode 2312 and the second positive electrode 2311.

[0172] The first adhesive applicator 280 can attach adhesive pieces 235 to the negative electrode 232 and the separator 233. The first adhesive applicator 280 can control the timing of the supply of adhesive pieces 235 so that the adhesive pieces 235 are located between the first positive electrode 2312 and the second positive electrode 2312 (the first positive electrode 2312 of the inner ring) or the second positive electrode 2311. In this way, after winding, the first positive electrode 2312 is positioned opposite the negative electrode 232 in the innermost ring of the electrode assembly 23, and the adhesive pieces 235 can avoid the positive electrode 231 of the inner ring, reducing the risk of the positive electrode 231 of the inner ring breaking brittlely and shedding powder due to overvoltage.

[0173] In some embodiments, the winding mechanism 250 includes a winding needle 251, which is a clamping winding needle or an adsorption winding needle; the negative electrode 232 is attached to the surface of the winding needle 251, and the winding needle 251 rotates to wind the positive electrode 231, the diaphragm 233 and the negative electrode 232 stacked in sequence.

[0174] For example, such as Figure 5As shown, the winding needle 251 is an adsorption type winding needle. The positive electrode 231, the separator 233 and the negative electrode 232 are arranged in sequence. The negative electrode 232 is directly attached to the surface of the winding needle 251. The winding needle 251 adsorbs the above-mentioned stacked layers by negative pressure adsorption and drives the stacked layers to wind. In the innermost circle, the first positive electrode 2312 can be opposite to the negative electrode 232.

[0175] The winding needle 251 can also be a clamping winding needle. For example, the winding needle 251 can clamp the first positive electrode 2312 and the separator 233. The negative electrode 232 is directly attached to the surface of the winding needle 251. Then, in the innermost circle, the first positive electrode 2312 can be opposite to the negative electrode 232.

[0176] By adopting the above technical solutions, the winding needle 251 can be a clamping winding needle, which uses the clamping winding needle to clamp the incoming material and then performs the winding operation; or, the winding needle 251 can be an adsorption winding needle, which uses the adsorption winding needle to adsorb and fix the incoming material and then performs the winding operation. In this way, the negative electrode sheet 232 can be directly attached to the surface of the winding needle 251, so that the negative electrode sheet 232 is located in the innermost circle of the electrode assembly 23, without the need to empty-wind multiple turns of the separator 233, thus solving the problem of redundant winding of the separator.

[0177] In some embodiments, the diaphragm 233 includes a first diaphragm 2331 and a second diaphragm 2332, and the third feeding mechanism 230 includes a first diaphragm feeding assembly 2301 for providing the first diaphragm 2331 and a second diaphragm feeding assembly 2302 for providing the second diaphragm 2332; the first adhesive applicator 280 is used to convey the stacked first diaphragm 2331, positive electrode 231, second diaphragm 2332 and negative electrode 232 to the winding mechanism 250, and to attach the adhesive 235 to the winding start end of the negative electrode 232 and the second diaphragm 2332.

[0178] The first adhesive applicator 280 can convey the first separator 2331, the positive electrode 231, the second separator 2332 and the negative electrode 232 stacked in sequence to the winding mechanism 250. Since the second separator 2332 and the negative electrode 232 are adjacent and stacked, the first adhesive applicator 280 can provide an adhesive 235 and attach the adhesive 235 to the winding start end of the negative electrode 232 and the second separator 2332. The winding mechanism 250 can wind the electrode and separator into an electrode assembly 23, such that the first positive electrode 2312 and the negative electrode 232 are arranged opposite each other in the innermost circle. After the electrode assembly 23 is wound and shaped, the first positive electrode 2312 is located between the first negative electrode straight portion 23211 and the second negative electrode straight portion 23212 in the negative electrode 232.

[0179] In some embodiments, the winding apparatus 200 further includes a composite mechanism 260 for rolling and bonding the first positive electrode sheet 2312 with one of the first separator 2331 and the second separator 2332 to form a composite sheet body 236.

[0180] The composite mechanism 260 is located upstream of the winding mechanism 250 and is capable of conveying the composite sheet 236 after roll forming to the winding mechanism 250. For example, the composite mechanism 260 roll forms the first positive electrode sheet 2312 with the second separator 2332. In some embodiments, the first separator 2331 is the upper separator, the second separator 2332 is the lower separator, and the first separator 2331 is located above the second separator 2332.

[0181] It is understandable that the composite structure can also be achieved by rolling the first positive electrode 2312 and the first separator 2331 together.

[0182] By setting up a composite mechanism 260 to combine the first positive electrode 2312 with the first separator 2331 or the second separator 2332, the alignment accuracy between the first positive electrode 2312 and the separator is improved. Furthermore, the first positive electrode 2312 can enter the winding needle 251 together with the first separator 2331 or the second separator 2332. On the one hand, the first positive electrode 2312 is less likely to detach from the separator or wrinkle when it enters the winding needle 251. On the other hand, the winding feeding speed and winding efficiency are improved. Moreover, the fact that the first positive electrode 2312 can be wound together with the first separator 2331 or the second separator 2332 into the winding needle 251 can also reduce the length of redundant winding at the head of the separator.

[0183] In some embodiments, the composite mechanism 260 is used to roll-press the first positive electrode 2312 and the second positive electrode 2311 with the second separator 2332 in sequence to form a composite sheet 236.

[0184] Since the first positive electrode 2312 is located in the inner ring of the second positive electrode 2311, in the composite sheet 236, the first positive electrode 2312 is located upstream of the second positive electrode 2311.

[0185] The composite mechanism 260 of this application embodiment combines the first positive electrode 2312 and the second positive electrode 2311 with the second separator 2332, realizing the pre-composite of the positive electrode 231 and the second separator 2332, improving the feeding speed of the incoming winding needle 251, improving the winding efficiency, and at the same time, improving the alignment accuracy of the positive electrode 231 and the second separator 2332, solving the problems of misalignment, wrinkling and uneven stacking of the positive electrode 231 under high-speed winding.

[0186] like Figure 8As shown, in some embodiments, the first feeding mechanism 210 includes a first feeding assembly 211 and a second feeding assembly 212. The first feeding assembly 211 is used to provide the positive electrode sheet 231 and cut the positive electrode sheet 231 into a first positive electrode sheet 2312. The second feeding assembly 212 is used to provide the positive electrode sheet 231 and cut the positive electrode sheet 231 into a second positive electrode sheet 2311. The composite mechanism 260 includes a first composite roller group 261 and a second composite roller group 262. 1 is located downstream of the first feeding assembly 211 and the second diaphragm feeding assembly 2302, and is used to composite the first positive electrode 2312 with the second diaphragm 2332; the second composite roller assembly 262 is located downstream of the second feeding assembly 212 and the second diaphragm feeding assembly 2302, and is used to composite the second positive electrode 2311 with the second diaphragm 2332; the second diaphragm 2332 and the first positive electrode 2312 and the second positive electrode 2311 on the second diaphragm 2332 form a composite sheet 236.

[0187] Both the first feeding assembly 211 and the second feeding assembly 212 include a feeding roller for releasing the positive electrode sheet 231 and a cutting assembly for cutting the positive electrode sheet 231, so as to provide a sheet-shaped first positive electrode sheet 2312 and a strip-shaped second positive electrode sheet 2311, respectively. Optionally, the first feeding assembly 211 and the second feeding assembly 212 are located on opposite sides of the winding equipment 200, and the first composite roller group 261 and the second composite roller group 262 are located in the middle of the winding equipment 200, so that the conveying path of the positive electrode sheet 231 is shorter and the flow line is smoother.

[0188] The first composite roller assembly 261 can receive the first positive electrode 2312 conveyed by the first feeding assembly 211 and the second separator 2332 conveyed by the second separator feeding assembly 2302 to composite the first positive electrode 2312 with the second separator 2332; the second composite roller assembly can receive the second positive electrode 2311 conveyed by the first feeding assembly 211 and the second separator 2332 conveyed by the second separator feeding assembly 2302 to composite the second positive electrode 2311 with the second separator 2332. Since both the first positive electrode 2312 and the second positive electrode 2311 are composited on the second separator 2332, the second separator 2332 and the first positive electrode 2312 and the second positive electrode 2311 on the second separator 2332 form a composite sheet 236.

[0189] It is understood that the first composite roller group 261 can be used to composite the first positive electrode 2312 with the head of the second separator 2332, and then the second positive electrode 2311 can be composited with the second separator 2332; or, the second positive electrode 2311 can be composited with the second separator 2332 and the two can be conveyed to the first composite roller group 261, so that the first positive electrode 2312 is composited with the head of the second separator 2332.

[0190] By adopting the above technical solution, the first feeding mechanism 210 includes a first feeding component 211 and a second feeding component 212, which can simultaneously provide the first positive electrode 2312 and the second positive electrode 2311, thereby improving the feeding efficiency; the composite mechanism 260 includes a first composite roller group 261 and a second composite roller group, which can enable the second diaphragm 2332 and the first positive electrode 2312 and the second positive electrode 2311 on the second diaphragm 2332 to form a composite sheet 236. The composite sheet 236 is conveyed to the winding mechanism 250, which improves the feeding speed of the incoming material entering the winding mechanism 250, improves the winding efficiency, and at the same time improves the alignment accuracy between the positive electrode 231 and the second diaphragm 2332, solving the problems of misalignment, wrinkling and uneven stacking of the positive electrode 231 under high-speed winding.

[0191] Please refer to Figure 8 and Figure 11 In some embodiments, the first feeding assembly 211 includes a first positive electrode sheet feeding assembly 2111, a first cutting member 2112, and a first adsorption belt 2113 arranged sequentially. The first adsorption belt 2113 is disposed between the first cutting member 2112 and the first composite roller group 261. The first cutting member 2112 is used to cut the positive electrode sheet 231 released by the first positive electrode sheet feeding assembly 2111 into a first positive electrode sheet 2312. The first adsorption belt 2113 is used to adsorb... The first positive electrode 2312 is attached and transferred to the first composite roller group 261. The first composite roller group 261 includes a first composite roller 2611 and a second composite roller 2612 arranged opposite to each other. The first composite roller 2611 has a normal pressure region 2611a and a negative pressure region 2611b distributed along its circumference. The normal pressure region 2611a and the negative pressure region 2611b alternately convey the stacked portion. The negative pressure region 2611b is used to adsorb the head of the first positive electrode 2312.

[0192] The first positive electrode feeding assembly 2111 includes an electrode feeding roller, and the first cutting member 2112 includes a cutter for cutting the positive electrode 231. The first adsorption belt 2113 is a conveyor belt with vacuum adsorption function for membranes. The surface of the first adsorption belt 2113 is provided with vacuum adsorption holes. Under the suction action of the vacuum pump, the vacuum adsorption holes adsorb the membrane to prevent the membrane from tilting or shifting during the transport process. In addition to adsorbing the membrane, the vacuum adsorption conveyor belt can also adsorb debris, dust and other impurities, reducing the negative impact of impurities on the membrane and the processing environment.

[0193] The first adsorption belt 2113 conveys the first positive electrode 2312 between the first composite roller 2611 and the second composite roller 2612. The first composite roller 2611 has a normal pressure zone 2611a and a negative pressure zone 2611b distributed circumferentially thereon. The adsorption force provided by the negative pressure zone 2611b is greater than that provided by the normal pressure zone 2611a. The first composite roller has a negative pressure chamber inside, which is used to connect to a vacuum pumping device. The surface of the negative pressure zone 2611b has vacuum adsorption holes that communicate with the vacuum chamber, so that the negative pressure zone 2611b can adsorb the first positive electrode 2312.

[0194] There are several ways to implement the atmospheric pressure zone 2611a. For example, the atmospheric pressure zone 2611a may not have a vacuum adsorption hole, or it may have a vacuum adsorption hole. At the same time, the first composite roller may have a vacuum breaking hole on its axial end face. Both the vacuum breaking hole and the vacuum adsorption hole in the atmospheric pressure zone 2611a are connected to the negative pressure chamber. When the vacuum pumping device pumps air into the negative pressure chamber, air from the external environment can be simultaneously drawn into the negative pressure chamber through both the vacuum breaking hole and the vacuum adsorption hole. The adsorption force of the vacuum adsorption hole corresponding to the vacuum breaking hole is smaller than that of the vacuum adsorption hole in the negative pressure zone 2611b.

[0195] The negative pressure zone 2611b can adsorb the head of the first positive electrode 2312. Optionally, the angle of the negative pressure zone 2611b in the circumferential direction of the first composite roller is smaller than the angle of the normal pressure zone 2611a in the circumferential direction of the first composite roller.

[0196] In use, after the first cutting member 2112 cuts the positive electrode sheet 231 into the first positive electrode sheet 2312, the first adsorption belt 2113 conveys the first positive electrode sheet 2312 to the space between the first composite roller and the second composite roller. The negative pressure zone 2611b adsorbs the head of the first positive electrode sheet 2312, which can reduce the risk of the first positive electrode sheet 2312 shifting. As the first composite roller rotates, the normal pressure zone 2611a is opposite to the first positive electrode sheet 2312. The adsorption force of the normal pressure zone 2611a is small, which is conducive to the separation of the first positive electrode sheet 2312 from the first composite roller, so that the first positive electrode sheet 2312 can be conveyed out of the first composite roller group 261 for the next operation.

[0197] In this embodiment, the first positive electrode 2312 is conveyed to the first composite roller group 261 via the first adsorption belt 2113. The head of the first positive electrode 2312 is adsorbed by the negative pressure zone 2611b of the first composite roller. In this way, by combining the first adsorption belt 2113 and the negative pressure zone 2611b of the first composite roller, the risk of the first positive electrode 2312 shifting, especially the risk of the head of the first positive electrode 2312 shifting (i.e., "head swinging"), can be eliminated. The first positive electrode 2312 is conveyed by the normal pressure zone 2611a of the first composite roller, which allows the first positive electrode 2312 to be smoothly separated from the first composite roller group 261. Therefore, the winding equipment 200 can improve the transfer accuracy of the first positive electrode 2312, thereby improving the alignment accuracy of the electrode in the electrode assembly 23.

[0198] Optionally, the second feeding assembly 212 includes a second positive electrode feeding assembly 2121 and a second cutting member 2122. The second positive electrode feeding assembly 2121 includes an electrode feeding roller for releasing the positive electrode 231, and the second cutting member 2122 is used to cut the positive electrode 231 to form a second positive electrode 2311.

[0199] In some embodiments, the winding apparatus 200 further includes a buffer mechanism 270 disposed between the second composite roller group 262 and the first composite roller group 261. The buffer mechanism 270 buffers the second positive electrode 2311 and the second diaphragm 2332 after composite connection. The buffer mechanism 270 is configured to maintain the rate at which the second positive electrode 2311 is fed into the winding mechanism 250 by releasing the internally buffered second positive electrode 2311 and the second diaphragm 2332.

[0200] For example, in some embodiments, the buffer mechanism 270 may include a plurality of adjusting rollers, which are movable and adjustable in the height direction; the second positive electrode 2311 and the second diaphragm 2332 after being composite connected pass through the plurality of adjusting rollers in sequence and are adjusted up and down in the height direction by the plurality of adjusting rollers, so as to buffer the second positive electrode 2311 and the second diaphragm 2332 into the buffer mechanism 270, or release the second positive electrode 2311 and the second diaphragm 2332 outward from the buffer mechanism 270.

[0201] With this configuration, the buffer mechanism 270 can maintain the rate at which the second positive electrode 2311 is fed into the winding mechanism 250 by releasing the second positive electrode 2311 and the second diaphragm 2332 that are internally buffered, thereby reducing the impact of other operations of the winding equipment 200 on the transmission speed and effectively improving the production rate of the electrode assembly 23.

[0202] Optionally, the winding device 200 further includes a second adhesive applicator 290, located downstream of the second cutting member 2122 and upstream of the buffer mechanism 270. The second adhesive applicator 290 can adhere the head and / or tail of the second positive electrode 2311 to the second separator 2332 with adhesive tape, thereby improving the alignment accuracy between the second positive electrode 2311 and the second separator 2332.

[0203] Please refer to Figures 8 to 10 In some embodiments, the second feeding mechanism 220 includes a negative electrode sheet feeding assembly 221, a third cutting member 222, and a second adsorption belt 223 arranged sequentially. The third cutting member 222 is used to cut the negative electrode sheet 232 released by the negative electrode sheet feeding assembly 221. The second adsorption belt 223 is disposed between the third cutting member 222 and the first adhesive applicator 280. The second adsorption belt 223 is used to fix and transport the negative electrode sheet 232 by vacuum adsorption.

[0204] The negative electrode feeding assembly 221 may include an electrode feeding roller, and the third cutting member 222 may include a cam cutter and a cutter holder. The cam cutter can rotate relative to the cutter holder and cooperates with the cutter holder to cut the negative electrode 232. The two ends of the second adsorption belt 223 are respectively arranged adjacent to the third cutting member 222 and the first adhesive applicator 280, and are used to convey the cut negative electrode 232 to the first adhesive applicator 280. The first adhesive applicator 280 is located downstream of the second adsorption belt 223, the first composite roller group 261 and the third feeding mechanism 230, and is capable of receiving and conveying the first diaphragm 2331, the positive electrode 231, the second diaphragm 2332 and the negative electrode 232.

[0205] With this configuration, the second adsorption belt 223 can transport the cut negative electrode sheet 232 to the adhesive application mechanism, preventing the membrane from lifting or shifting during transport and improving the yield of adhesive application for the negative electrode sheet 232.

[0206] In some embodiments, the first feeding mechanism 210 is further configured to cut the positive electrode 231 into at least one third positive electrode 2313, the third positive electrode 2313 being wound around the outer ring of the second positive electrode 2311.

[0207] The third positive electrode 2313 is wound around the outer ring of the second positive electrode 2311, that is, the third positive electrode 2313 is located on the side of the second positive electrode 2311 away from the winding center of the electrode assembly 23.

[0208] In this way, the electrode assembly 23 manufactured by the winding equipment 200 can flexibly combine the stacking part and the winding part. By setting the third positive electrode 2313 on the outer ring of the second positive electrode 2311, the third positive electrode 2313 can fill the arc-shaped outer space naturally formed by the winding structure, thereby improving the space utilization and the energy density of the battery cell 20. The third positive electrode 2313 avoids the corner area 23b, reducing the risk of electrode breakage and short circuit of the battery cell 20 caused by external forces (such as collisions and compression), thereby improving the reliability of the battery cell 20.

[0209] In some embodiments, the winding device 200 includes a first feeding mechanism 210, a second feeding mechanism 220, a third feeding mechanism 230, a winding mechanism 250, a composite mechanism 260, and a first adhesive applicator 280. The composite mechanism 260 is used to roll-press the positive electrode sheet 231 with one of the first diaphragm 2331 and the second diaphragm 2332. The first adhesive applicator 280 is located downstream of the composite mechanism 260 and each feeding mechanism, and upstream of the winding mechanism 250. The first adhesive applicator 280 is used to convey the first diaphragm 2331, the positive electrode sheet 231, the second diaphragm 2332, and the negative electrode sheet 232, which are stacked in sequence, to the winding mechanism 250, and to attach the adhesive 235 to the winding start end of the negative electrode sheet 232 and the second diaphragm 2332.

[0210] To save space occupied by the winding equipment 200 and to streamline the film transport path, in some embodiments, the first feeding mechanism 210 includes a first feeding component 211 and a second feeding component 212, which are located at opposite ends of the winding equipment 200. The first diaphragm 2331 is the upper diaphragm, and the second diaphragm 2332 is the lower diaphragm. The first diaphragm feeding component 2301 and the first feeding component 211 are located on the same side, while the second feeding component 212 and the second diaphragm feeding component 2302 are located on the other side. The second feeding mechanism 220 and the first adhesive applicator 280 can be arranged adjacent to each other.

[0211] Please refer to Figures 1 to 7 This application embodiment also provides a battery device 100, which includes a battery cell 20 as described above.

[0212] The battery device 100 provided in this application embodiment includes the battery cell 20 as described above, thus the battery device 100 has a high energy density.

[0213] Please refer to Figures 1 to 7 This application embodiment also provides an electrical device, which includes a battery device 100 as described above, the battery device 100 being used to provide electrical energy.

[0214] The electrical equipment provided in this application includes the battery device as described above, thereby achieving a high energy density in the battery device.

[0215] The above are merely preferred embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A winding apparatus for manufacturing electrode assemblies in a battery cell, characterized in that, The winding equipment includes: The first feeding mechanism is used to provide a positive electrode sheet and cut the positive electrode sheet to form a first positive electrode sheet and a second positive electrode sheet. The second feeding mechanism is used to provide the negative electrode sheet; The third feeding mechanism is used to provide the diaphragm; A winding mechanism includes a winding needle for winding the positive electrode sheet, the diaphragm, and the negative electrode sheet into an electrode assembly; The first adhesive applicator is used to convey the stacked positive electrode sheet, the separator and the negative electrode sheet to the winding mechanism, and to attach the adhesive to the winding start end of the negative electrode sheet and the separator. In the innermost ring of the electrode assembly, the winding start ends of the first positive electrode and the negative electrode are positioned opposite each other on the winding needle.

2. The winding equipment as described in claim 1, characterized in that, Along the conveying direction of the first adhesive applicator, the starting end of the winding of the negative electrode sheet is located downstream of the first first positive electrode sheet; wherein, The number of first positive electrode plates is multiple, and the multiple first positive electrode plates are arranged sequentially at intervals, with the adhesive member located between the first first positive electrode plate and the second first positive electrode plate; or, The number of the first positive electrode is one, and the adhesive is located between the first positive electrode and the second positive electrode.

3. The winding equipment as described in claim 1, characterized in that, The coiled needle is a clamping coiled needle or an adsorption coiled needle; The negative electrode sheet is attached to the surface of the winding needle, and the winding needle rotates to wind the positive electrode sheet, the diaphragm, and the negative electrode sheet.

4. The winding equipment as described in claim 1, characterized in that, The diaphragm includes a first diaphragm and a second diaphragm, and the third feeding mechanism includes a first diaphragm feeding assembly for providing the first diaphragm and a second diaphragm feeding assembly for providing the second diaphragm; The first adhesive applicator is used to convey the stacked first diaphragm, the positive electrode, the second diaphragm, and the negative electrode to the winding mechanism, and to attach the adhesive to the winding start end of the negative electrode and the second diaphragm.

5. The winding equipment as described in claim 4, characterized in that, The winding equipment further includes a composite mechanism for rolling and bonding the first positive electrode sheet with one of the first separator and the second separator to form a composite sheet.

6. The winding apparatus as described in claim 5, characterized in that, The composite mechanism is used to roll and laminate the first positive electrode sheet and the second positive electrode sheet with the second separator in sequence to form the composite sheet body.

7. The winding apparatus as described in claim 6, characterized in that, The first feeding mechanism includes a first feeding component and a second feeding component for releasing the positive electrode sheet; The composite mechanism includes a first composite roller group and a second composite roller group. The first composite roller group is located downstream of the first feeding assembly and the second diaphragm feeding assembly, and is used to composite the first positive electrode sheet with the second diaphragm. The second composite roller group is located downstream of the second feeding assembly and the second diaphragm feeding assembly, and is used to composite the second positive electrode sheet with the second diaphragm. The second diaphragm and the first positive electrode sheet and the second positive electrode sheet on the second diaphragm are formed into a composite sheet body.

8. The winding apparatus as described in claim 7, characterized in that, The first feeding assembly includes a first positive electrode sheet feeding assembly, a first cutting member, and a first adsorption belt arranged sequentially. The first adsorption belt is located between the first cutting member and the first composite roller group. The first cutting member is used to cut the positive electrode sheet released by the first positive electrode sheet feeding assembly into a first positive electrode sheet. The first adsorption belt is used to adsorb the first positive electrode sheet and transfer the first positive electrode sheet to the first composite roller group. The first composite roller group includes a first composite roller and a second composite roller arranged opposite to each other. The first composite roller has an atmospheric pressure zone and a negative pressure zone distributed along its circumference. The atmospheric pressure zone and the negative pressure zone alternately convey the first positive electrode sheet. The negative pressure zone is used to adsorb the head of the first positive electrode sheet.

9. The winding apparatus as described in claim 8, characterized in that, The winding equipment further includes a buffer mechanism disposed between the second composite roller group and the first composite roller group. The buffer mechanism buffers the second positive electrode sheet and the second separator after composite connection. The buffer mechanism is configured to maintain the rate at which the second positive electrode sheet is fed into the winding mechanism by releasing the internally buffered second positive electrode sheet and the second separator.

10. The winding apparatus according to any one of claims 1-9, characterized in that, The second feeding mechanism includes a negative electrode sheet feeding assembly, a third cutting member, and a second adsorption belt arranged in sequence. The third cutting member is used to cut the negative electrode sheet released by the negative electrode sheet feeding assembly. The second adsorption belt is located between the third cutting member and the first adhesive applicator. The second adsorption belt is used to adsorb and transport the negative electrode sheet.

11. The winding apparatus according to any one of claims 1-9, characterized in that, The first feeding mechanism is also used to cut the positive electrode sheet into at least one third positive electrode sheet, the third positive electrode sheet being used to wind around the outer ring of the second positive electrode sheet.

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