Electrode assembly, battery cell, battery and electric device

Abstract

The invention relates to an electrode assembly, a battery monomer, a battery and a power utilization device, the electrode assembly comprises pole pieces and diaphragms, each diaphragm comprises a main body section, and the pole pieces and the main body sections of the diaphragms are stacked and wound to form an electrode main body; at least one axial end of the electrode main body is provided with a tab protruding out of the main body section; the at least one layer of diaphragm comprises a first extension section connected with the main body section, and the first extension section is wound outside the electrode main body for at least one circle; the first extension section is provided with a convex part protruding out of the main body section along the axial end part, and at least part of the convex part is folded towards one side close to the center of the electrode main body so as to cover the edge part of the tab at the corresponding end. The first extension sections are wound at all positions of the electrode main body in the axial direction, so that the radiuses or diameters of all parts of the electrode assembly can be ensured to be the same, all parts of the electrode assembly are uniformly expanded when the electrode assembly is expanded, the outer ring pole piece is not easy to break, and the use performance of the battery monomer is ensured.

Description

Technical Field

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

[0002] With the rapid expansion and development of the new energy industry, batteries with high energy density and high safety characteristics are attracting increasing attention. Among them, cylindrical steel-cased batteries have become one of the important development directions.

[0003] Currently, high-energy-density cylindrical battery cells are generally made using a negative electrode system composed of silicon-based materials and graphite. However, silicon-based materials exhibit a significant volume expansion effect during charge-discharge cycles, and the degree of expansion of the electrode assembly is directly limited by the effective diameter inside the steel shell.

[0004] Typically, electrode assemblies have tabs at their axial ends. To prevent the tab edges from abnormally contacting the steel shell and causing electrical conductivity issues, insulating adhesive is often wrapped around the outer periphery of the electrode assembly near the tabs and folded over to cover the tab edges, thus insulating the tab edges from the steel shell. This design inevitably reduces the effective inner diameter of the area within the steel shell where the insulating adhesive is located. This change leads to significant thickness variations in the outer electrode plates of the electrode assembly. When the stress imbalance is severe, it can cause the outer electrode plates to break. In other words, when the electrode assembly expands, the insulating adhesive will constrict the electrode assembly, leaving marks on the outer electrode plates at the edge of the insulating adhesive. The outer electrode plates are prone to breakage at these marks. Summary of the Invention

[0005] Therefore, it is necessary to address the problem that the traditional method of using insulating adhesive to prevent the electrode edge from contacting the casing for electrical conduction easily leads to the breakage of the outer electrode sheet, and to provide an electrode assembly, battery cell, battery, and power device that can reduce the breakage of the outer electrode sheet.

[0006] On one hand, this application provides an electrode assembly, including: The electrode and the separator, each separator layer includes a main body segment, the electrode and the main body segment of the separator are stacked and wound to form an electrode body; at least one end of the electrode body in the axial direction has an electrode tab protruding from the main body segment; At least one of the diaphragms includes a first extension connected to the main body segment, the first extension being wound around the electrode body at least one turn; the end of the first extension along the axial direction has a protrusion protruding from the main body segment, at least a portion of the protrusion being folded toward the center of the electrode body to cover the edge portion of the tab at the corresponding end.

[0007] In one embodiment, the electrode body includes a body, and the tab at at least one end includes a transition portion and an electrical connection portion, the transition portion being disposed between the electrical connection portion and the body; The electrical connection portion is bent toward the side closer to the center of the body relative to the transition portion, and the portion of the protrusion protruding from the transition portion is folded toward the side closer to the center of the body and covers the edge portion of the electrical connection portion.

[0008] In one embodiment, the first extension segment is integrally formed with its corresponding main body segment; or The first extension segment and its corresponding main body segment are separately disposed and bonded together.

[0009] In one embodiment, the electrode assembly has a circumference C, and the first extension has a first length L1 along the winding direction, L1 = (1.5-4)C; and / or The first extension section is wound around the electrode body 1.5-3 times.

[0010] In one embodiment, the protrusion has a first height Wb along the axial direction, where Wb = 10.5 mm - 18.5 mm; and / or The first extension includes a main body portion and the protrusion portion connected to each other, the main body portion being connected to the main body segment, and the end of the protrusion portion away from the main body portion having a slit.

[0011] In one embodiment, the slit is present on each turn of the first extension wound around the electrode body; and / or The height of the cut is less than the height of the protrusion.

[0012] In one embodiment, all of the diaphragms include the first extension, and the tails of all of the diaphragms are flush. or Part of the diaphragm includes the first extension.

[0013] On the other hand, this application also provides a battery cell, including a current collector and the aforementioned electrode assembly; The current collector is electrically connected to the corresponding electrode tab, and the folded portion of the protrusion also covers the end face of the current collector away from the electrode assembly.

[0014] In one embodiment, the battery cell further includes a housing and an insulating gasket. The insulating gasket includes an insulating portion and a guiding portion connected to each other. The insulating portion is disposed along the axial direction between the current collector and the end wall of the housing. The guiding portion is connected to the edge of the insulating portion along the axial direction near the current collector. The guide portion has an arc-shaped guide surface, which is used to guide the first extension section to fold over and cover the end face of the collector plate opposite to the electrode assembly.

[0015] In one embodiment, the thickness of the first extension segment is greater than the thickness of the main body segment; or The first extension segment is made of a first material, and the main body segment is made of a second material, wherein the strength of the first material is greater than the strength of the second material.

[0016] In one embodiment, the guide portion has a first wall thickness W1 at one end away from the insulating portion along the axial direction, and a second wall thickness W2 at the end connected to the insulating portion. The electrode assembly has a first radius R1, and the current collector has a second radius R2, where R2 < R1; wherein W1 = 0.1 mm - 0.3 mm, and W2 - W1 - (R1 - R2) = 1 mm - 3 mm. and / or The protrusion is provided with an expansion member that expands upon contact with electrolyte, and the expansion member fills the space between the guide portion and the electrode assembly.

[0017] In one embodiment, the protrusion covering the end face of the collector plate has a first dimension L2, 7mm≤L2≤15mm.

[0018] Furthermore, this application also provides a battery, including the aforementioned battery cell.

[0019] On the other hand, this application also provides an electrical device that includes the aforementioned battery cell, or includes the aforementioned battery.

[0020] Compared with the prior art, this application has the following beneficial effects: Because at least a portion of the protrusion folds towards the side closer to the main body to cover the edge of the tab at that end, and the separator itself is insulating, when the electrode assembly is installed in the housing, the protrusion can prevent the edge of the tab at that end from contacting the housing for electrical conduction. In other words, the protrusion can replace the insulating adhesive in the prior art, achieving insulation between the corresponding tab and the housing. This arrangement, where the first extension section is wound around the electrode body (meaning the first extension section is wound around the electrode body at various axial positions), ensures that the radius or diameter of the electrode assembly is the same throughout. Therefore, when the electrode assembly expands, its expansion is uniform, reducing the likelihood of breakage of the outer electrode sheet and ensuring the performance of the battery cell. Attached Figure Description

[0021] Figure 1 A partial structural diagram of a battery cell provided in an embodiment of this application; Figure 2 A partial structural diagram of a battery cell provided in another embodiment of this application; Figure 3 An unfolded view of a diaphragm having a first extension section for an electrode assembly provided in an embodiment of this application; Figure 4 An unfolded view of a diaphragm having a first extension section for an electrode assembly provided in another embodiment of this application; Figure 5 An unfolded view of the first extension of an electrode assembly provided in yet another embodiment of this application; Figure 6 A partial structural diagram of a battery cell provided in another embodiment of this application; Figure 7 This is a partial structural diagram of a battery cell provided in another embodiment of this application.

[0022] Explanation of reference numerals in the attached figures: 1000, Battery cell; 100, Electrode assembly; 10, Electrode; 10a, Positive electrode; 10b, Negative electrode; 20, Separator; 21, Main body section; 22, First extension section; 221, Main body part; 222, Protrusion; 2221, Slit; 30, Electrode body; 31, Tab; 311, Transition part; 312, Electrical connection part; 31a, Positive tab; 31b, Negative tab; 32, Body; 200, Current collector; 300, Housing; 400, Insulating gasket; 401, Insulating part; 402, Guide part; 4021, Guide surface; 500, Terminal post; 600, Insulating component. Detailed Implementation

[0023] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0024] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention 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. Therefore, they should not be construed as limitations on this invention.

[0025] 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 at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0026] In this invention, unless otherwise explicitly 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, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0027] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0028] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0029] See Figure 1 This application provides an electrical device, a battery, and a battery cell 1000. The electrical device includes the battery or the battery cell 1000 and is capable of being powered by the battery or the battery cell 1000. The electrical device can be a vehicle, mobile phone, portable device, laptop computer, ship, spacecraft, electric toy, power tool, energy storage device, amusement equipment, elevator, and lifting equipment, etc. Electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, or electric airplane toys, etc.; power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc.; energy storage devices can be energy storage walls, base station energy storage, container energy storage, etc.; amusement equipment can be a carousel, a drop tower, etc.

[0030] The vehicle 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 vehicles, etc. For new energy vehicles, the aforementioned battery can serve as a driving power source, thereby replacing fossil fuels to provide propulsion. This application does not impose any special restrictions on the aforementioned electrical devices.

[0031] The aforementioned battery can be a battery pack or a battery module. When the battery is a battery pack, the battery pack includes a battery management system (BMS) and multiple battery cells 1000. The multiple battery cells 1000 can be electrically connected in series, parallel, or a combination of series and parallel connections, and communicate with the battery management system, which controls and monitors the operating status of each battery cell 1000. Alternatively, the multiple battery cells 1000 can first be combined with a module management system to form a battery module, and then the multiple battery modules can be electrically connected in series, parallel, or a combination of series and parallel connections to form a battery pack together with the battery management system.

[0032] Multiple battery cells 1000 can be installed in a housing. The housing may include a first part and a second part, which overlap each other, jointly defining a space for accommodating the battery cells 1000. The second part may be a hollow structure with one open end, while the first part may be a plate-like structure, covering the open side of the second part so that the first and second parts jointly define the accommodating space. Alternatively, both the first and second parts may be hollow structures with one open side, with the open side of the first part covering the open side of the second part. Of course, the housing formed by the first and second parts can be of various shapes, such as a cylinder or a cuboid. The individual battery cells 1000 and the battery management system can be electrically connected via electrical connectors, which may be busbars. The battery cells 1000 may be lithium-ion, sodium-ion, or magnesium-ion batteries, and their external contours may be cylindrical, flat, cuboid, or other shapes, but are not limited to these. Specifically, in this embodiment, the battery cell 1000 is a lithium-ion cylindrical battery.

[0033] See Figure 1 and Figure 2 In one embodiment of this application, the battery cell 1000 includes a housing 300 and an electrode assembly 100. The housing 300 is a hollow structure with an internal cavity for accommodating the electrode assembly 100, electrolyte, and other components. The cavity has an opening through which the electrode assembly 100 is inserted into the housing 300. In this embodiment, the battery cell 1000 is a cylindrical battery, and the outer contour of the housing 300 is cylindrical with a circular opening. The battery cell 1000 also includes a cover plate (not shown), which is installed at and covers the opening of the housing 300, thereby creating a relatively closed environment inside the housing 300 to isolate the electrode assembly 100 from the external environment. Since the shape of the cover plate needs to match the shape of the opening, the cover plate is approximately circular.

[0034] Continue reading Figure 1 The electrode assembly 100 includes an electrode 10 and a diaphragm 20. Each diaphragm 20 includes a main body segment 21. The electrode 10 and the main body segment 21 of the diaphragm 20 are stacked and wound to form an electrode body 30.

[0035] In some embodiments, the electrode 10 includes a positive electrode 10a and a negative electrode 10b, and the separator 20 can be a single layer disposed between the positive electrode 10a and the negative electrode 10b. That is, in this embodiment, the positive electrode 10a and the negative electrode 10b are isolated by a single-layer separator 20. In another embodiment, the separator 20 can be two layers, wherein the main body segment 21 of one separator 20, the positive electrode 10a, the main body segment 21 of the other separator 20, and the negative electrode 10b are sequentially stacked and wound to form the electrode body 30. That is, in this embodiment, the positive electrode 10a and the negative electrode 10b are isolated by two independent separators 20. In other embodiments, the electrode assembly 100 may include more than two layers of separators 20, and the positive electrode 10a and negative electrode 10b may also be more than one layer. The main body segment 21 of the multilayer separators 20, the positive electrode 10a, and the negative electrode 10b are stacked and wound to form the electrode body 30, and a separator 20 is disposed between adjacent electrode 10s. That is, in this embodiment, more than two independent separators 20 are used to achieve isolation between the positive electrode 10a and the negative electrode 10b.

[0036] For further reference Figure 1 Electrode body 30 axial direction ( Figure 1 At least one end of the body (in the Z direction) has a tab 31 that protrudes from the main body segment 21.

[0037] In some embodiments, both ends of the electrode body 30 have tabs 31 protruding from the main body segment 21, and the tabs 31 at both ends are positive tab 31a and negative tab 31b, respectively. That is, the positive tab 31a and negative tab 31b are located at both ends of the electrode body 30 in the axial direction and both protrude from the main body segment 21. Generally, the positive tab 31a is formed from the portion of the positive electrode sheet 10a that is not coated with the active material layer, and the negative tab 31b is formed from the portion of the negative electrode sheet 10b that is not coated with the active material layer. In other embodiments, the electrode body 30 has only one end with a tab 31 protruding from the main body segment 21, and the tab 31 at this end includes both a positive tab 31a and a negative tab 31b.

[0038] Continue reading Figure 1 and Figure 3At least one diaphragm 20 includes a first extension 22 connected to its main body 21, the first extension 22 being wound around the electrode body 30 at least one turn. The axial end of the first extension 22 has a protrusion 222 protruding from the main body 21, at least a portion of which is folded towards the center of the electrode body 30 to cover the edge portion of the corresponding end tab 31. That is, when the first extension 22 is wound around the electrode body 30 and not folded towards the center of the electrode body 30, at least one axial end of the first extension 22 protrudes from the main body 21, and the portion protruding from the main body 21 forms the protrusion 222. At least a portion of the protrusion 222 is folded towards the center of the electrode body 30 to cover the edge portion of the corresponding end tab 31.

[0039] It should be noted that the center of the electrode body 30 is the winding axis of the electrode body 30, which corresponds to the position of the starting end of the winding of the electrode body 30.

[0040] It should also be noted that the fact that at least a portion of the protrusion 222 folds towards the center of the electrode body 30 to cover the edge portion of the corresponding tab 31 means that the first extension 22 also includes a main body portion 221 connected to the main body portion 21. The protrusion 222 is located at one or both ends of the main body portion 221 along the axial direction. At least a portion of the protrusion 222 folds towards the center of the electrode body 30 relative to the main body portion 221 to cover the edge portion of the corresponding tab 31. The axial dimension of the main body portion 221 in the electrode body 30 is not less than the axial dimension of the main body portion 21 in the electrode body 30. Typically, the axial dimension of the main body portion 221 in the electrode body 30 is equal to the axial dimension of the main body portion 21 in the electrode body 30.

[0041] In some embodiments, the electrode body 30 has tabs 31 at both ends along its axial direction. The first extension 22 may have a protrusion 222 at one end along the axial direction of the electrode body 30, or it may have protrusions 222 at both ends along the axial direction of the electrode body 30. In some specific embodiments, when the housing 300 needs to be electrically connected to one end of the tab 31 to serve as the positive or negative electrode of the battery cell 1000, the other end of the tab 31 needs to be insulated from the housing 300. In this case, the first extension 22 can have a protrusion 222 at one end along the axial direction of the electrode body 30. The protrusion 222 folds over and covers the edge of the tab 31 at that end to achieve insulation between the tab 31 at that end and the housing 300. The protrusion 222 may be located at the end of the electrode body 30 with the positive tab 31a, in which case the protrusion 222 covers the edge portion of the positive tab 31a. The protrusion 222 can also be located at the end of the electrode body 30 with the negative electrode tab 31b, in which case the protrusion 222 covers the edge portion of the negative electrode tab 31b. When the housing 300 needs to be insulated from both ends of the tabs 31, the first extension 22 is provided with protrusions 222 at both ends of the electrode body 30 in the axial direction, and the protrusion 222 at each end is folded over to cover the tab 31 at the corresponding end, so as to achieve insulation between the tabs 31 at both ends and the housing 300.

[0042] In other embodiments, when the electrode body 30 is provided with a tab 31 at one end in the axial direction, that is, when the positive tab 31a and the negative tab 31b are both located at the same end of the electrode body 30, the first extension 22 only needs to have a protrusion 222 at the end of the electrode body 30 where the tab 31 is provided.

[0043] Since at least a portion of the protrusion 222 folds towards the center of the electrode body 30 to cover the edge of the corresponding end tab 31, and the separator 20 itself is insulating, when the electrode assembly 100 is installed in the housing 300, the protrusion 222 can prevent the corresponding end tab 31 from contacting the housing 300 for electrical conduction. In other words, the protrusion 222 can replace the insulating adhesive in the prior art, achieving insulation between the corresponding end tab 31 and the housing 300. With this arrangement, since the first extension 22 is wound around the electrode body 30, meaning the electrode body 30 is wound with the first extension 22 at various axial positions, the radius or diameter of the electrode assembly 100 is the same everywhere. Therefore, when the electrode assembly 100 expands, its expansion is uniform, making it less likely to cause breakage of the outer electrode sheet 10, thus ensuring the performance of the battery cell 1000.

[0044] Optionally, continue reading Figure 1The electrode body 30 includes a main body 32, and a tab 31 at at least one end includes a transition portion 311 and an electrical connection portion 312. The transition portion 311 is located between the electrical connection portion 312 and the main body 32. The electrical connection portion 312 is bent relative to the transition portion 311 towards the center of the main body 32 (which is also the center of the electrode body 30). The portion of the protrusion 222 protruding from the transition portion 311 is folded towards the center of the main body 32 and covers the edge portion of the electrical connection portion 312. This arrangement keeps the electrical connection portion 312 as far away from the housing 300 as possible to reduce contact between the tab 31 and the housing 300; and the fact that the protrusion 222 can fold over to cover the edge portion of the electrical connection portion 312 ensures that the protrusion 222 completely covers the edge of the transition portion 311, thus ensuring the insulation effect between the tab 31 and the housing 300.

[0045] In some embodiments, the electrode body 30 has a positive electrode tab 31a and a negative electrode tab 31b at its two axial ends. One end of the housing 300 has an opening, and a cover plate is installed at the opening end. The cover plate, housing 300, and negative electrode tab 31b are negatively charged. See also... Figure 2 The closed end of the housing 300 is provided with a terminal hole, in which a positive terminal 500 is installed. An insulating member 600 is provided between the positive terminal 500 and the housing 300 to achieve insulation between the positive terminal 500 and the housing 300. The positive terminal 500 is positively charged. Since the positive electrode tab 31a is electrically connected to the positive terminal 500, the positive electrode tab 31a needs to be insulated from the housing 300. At this time, the first extension 22 has a protrusion 222 at one end corresponding to the positive electrode tab 31a. At least a portion of the protrusion 222 is folded towards the side closer to the center of the electrode body 30 to cover the edge portion of the positive electrode tab 31a at that end.

[0046] Of course, in some other embodiments, the housing 300 may be positively charged, and the first extension 22 may have a protrusion 222 at one end corresponding to the negative electrode tab 31b. At least a portion of the protrusion 222 may be folded toward the side closer to the center of the electrode body 30 to cover the edge portion of the negative electrode tab 31b at that end. This is not limited here.

[0047] For ease of explanation, the following description will be based on the example of the housing 300 being negatively charged, with at least a portion of the protrusion 222 folded towards the side closer to the center of the electrode body 30, covering the edge portion of the positive electrode tab 31a at that end. However, this description is merely an example and does not limit the scope of protection of this application.

[0048] In some embodiments, all diaphragms 20 include a first extension 22, and the tails of all diaphragms 20 are flush. Thus, when the electrode 10 is cut, all diaphragms 20 are wound together to form the last few turns of the electrode assembly 100.

[0049] In other embodiments, a portion of the diaphragm 20 includes a first extension 22. Optionally, the tail of the diaphragm 20 with the first extension 22 extends beyond the tails of the other diaphragms 20. Alternatively, the tails of the other diaphragms 20 may be flush with the tail of the diaphragm 20 with the first extension 22. In any case, it is sufficient to ensure that the first extension 22 covers the edge portion of the positive electrode tab 31a at that end.

[0050] In some embodiments, see Figure 4 The first extension segment 22 and its corresponding main body segment 21 are integrally formed. At this point, the main body segment 21 and the first extension segment 22 can be formed by cutting. This arrangement ensures the connection between the first extension segment 22 and the main body segment 21.

[0051] In other embodiments, see further description. Figure 3 The first extension segment 22 and its corresponding main body segment 21 are separately set and bonded together. This arrangement is more convenient from a process perspective and can simplify the process.

[0052] In some embodiments, see further reference. Figure 3 and Figure 4 The protrusion 222 has a first height Wb along the axial direction, where Wb = 10.5 mm - 18.5 mm. This arrangement ensures that the protrusion 222 covers the edge portion of the positive electrode tab 31a.

[0053] Optionally, Wb can be 10.5 mm, 12.5 mm, 14.5 mm, 16.5 mm or 18.5 mm, etc., and is not limited here.

[0054] Further reading Figures 3-5 The end of the protrusion 222 away from the main body 221 has a notch 2221. Considering that the protrusion 222 is prone to wrinkling when it bends towards the center or axis of the electrode body 30, a notch 2221 is provided at the end of the protrusion 222 away from the main body 221. The notch 2221 does not remove the material of the protrusion 222 but only forms a cut, thereby avoiding wrinkling when the protrusion 222 bends towards the axis, which is beneficial to the manufacturing of the electrode assembly 100.

[0055] Each turn of the first extension 22 wound around the electrode body 30 has a slit 2221 to prevent the protrusion 222 of each turn of the first extension 22 wound around the electrode body 30 from wrinkling when it falls toward the axis.

[0056] Specifically, each of the protrusions 222 of the first extension segment 22 has 3-8 slits 2221. Of course, in some other embodiments, the number of slits 2221 provided on the protrusions 222 of each of the first extension segments 22 is not limited.

[0057] Generally, the height of the notch 2221 is less than the height of the protrusion 222. This ensures that the notch 2221 exists only at the folded portion of the protrusion 222 near the center of the electrode body 30, while other parts of the protrusion 222 do not have the notch 2221. This prevents the housing 300 from contacting the positive electrode tab 31a at the notch 2221, thus ensuring the insulation effect between the edges of the housing 300 and the positive electrode tab 31a.

[0058] In some embodiments, the electrode assembly 100 has a circumference C, and the first extension 22 has a first length L1 along the winding direction, where L1 = (1.5-4)C. Setting L1 = (1.5-4)C ensures that even when the first extension 22 is loose, the edge of the entire loop of the positive electrode tab 31a is still covered by the protrusion 222, and also prevents the first extension 22 from being too long and having too many loops outside the electrode body 30, thus affecting the diameter of the entire electrode assembly 100.

[0059] Optionally, L1 can be 1.5C, 2C, 2.5C, 3C, 3.5C or 4C, etc., without specific limitations.

[0060] In other embodiments, the number of turns of the first extension 22 around the electrode body 30 is 1.5-3. This arrangement ensures that even when the first extension 22 is loose, the edge of the entire loop of the positive electrode tab 31a is still covered by the protrusion 222, and also prevents the first extension 22 from being too long and having too many turns around the electrode body 30, thus affecting the diameter of the entire electrode assembly 100.

[0061] Optionally, the number of turns of the first extension 22 around the electrode body 30 is 1.5, 2, 2.5, and 3, etc., without specific limitation.

[0062] In some embodiments, see further reference. Figure 1 The battery cell 1000 also includes a current collector 200, which is electrically connected to the positive electrode tab 31a. The folded portion of the protrusion 222 also covers the outer side of the end face of the current collector 200 away from the electrode assembly 100. Since most of the positive electrode tab 31a is covered by the current collector 200, the folded portion of the protrusion 222 can also cover the edge portion of the positive electrode tab 31a. Thus, the protrusion 222 not only prevents the edge portion of the positive electrode tab 31a from contacting the housing 300 and conducting electricity, but also prevents the edge portion of the current collector 200 from contacting the housing 300 and conducting electricity, ensuring the insulation effect between the positive electrode tab 31a and the housing 300.

[0063] See Figure 6The portion of the protrusion 222 that covers the end face of the current collector 200 has a first dimension L2, 7mm≤L2≤15mm. This ensures that the protrusion 222 completely covers the edge portion (outer ring portion) of the positive electrode tab 31a and covers a sufficient portion of the edge portion of the current collector 200, thus ensuring the insulation effect between the positive electrode tab 31a and the housing 300.

[0064] Optionally, L2 can be 7mm, 9mm, 11mm, 13mm or 15mm, etc., without specific limitations.

[0065] Further reading Figure 6 and Figure 7 The battery cell 1000 also includes an insulating gasket 400, which includes an insulating portion 401 and a guiding portion 402 connected to each other. The insulating portion 401 is axially disposed between the end walls of the current collector 200 and the housing 300. The guiding portion 402 is axially connected to the insulating portion 401 on one side edge near the current collector 200. The guiding portion 402 has an arc-shaped guiding surface 4021, which guides the first extension segment 22 to fold over and cover the end face of the current collector 200 opposite to the electrode assembly 100. On the one hand, the insulating pad 400 can prevent the current collector 200 from short-circuiting with the housing 300; on the other hand, when the electrode assembly 100 is inserted into the housing, the arc-shaped guide surface 4021 of the guide portion 402 can cause at least a portion of the protrusion 222 to bend toward the axial position of the electrode body 30, so as to cover the edge of the positive electrode tab 31a not covered by the current collector 200 and cover the end face of the current collector 200 away from the electrode assembly 100, which facilitates the folding of the protrusion 222; furthermore, the guide portion 402 is directly provided on the insulating pad 400 without adding a new structure, which facilitates the processing and manufacturing of the battery cell 1000.

[0066] Continue reading Figure 7 The guide portion 402 has a first wall thickness W1 at one end axially away from the insulating portion 401, and a second wall thickness W2 at the other end connected to the insulating portion 401. The electrode assembly 100 has a first radius R1, and the current collector 200 has a second radius R2, where R2 < R1. Figure 7 The X direction is a radial direction of the electrode body 30. Where W1 = 0.1mm - 0.3mm, W2 - W1 - (R1 - R2) = 1mm - 3mm. This arrangement ensures that when the electrode assembly 100 is inserted into the housing, there is a certain gap between the electrode assembly 100 and the guide portion 402, allowing the electrode assembly 100 to be placed inside the guide portion 402, and the protrusion 222 to bend towards the axial position under the guidance of the arc-shaped guide surface 4021.

[0067] In some specific embodiments, the thickness of the first extension 22 is greater than the thickness of the main body 21, so that the protrusion 222 of the first extension 22 can be rolled back or folded towards the axial position under the guidance of the guide 402.

[0068] In other embodiments, the first extension segment 22 is made of a first material, and the main body segment 21 is made of a second material, wherein the strength of the first material is greater than that of the second material. This also facilitates the retraction or folding of the protrusion 222 of the first extension segment 22 towards the axial position under the guidance of the guide portion 402.

[0069] In some embodiments, the protrusion 222 is provided with an expansion member that expands upon contact with the electrolyte, and the expansion member fills the space between the guide portion 402 and the electrode assembly 100. The expansion member not only provides a limiting effect on the protrusion 222, but also alleviates the expansion of the electrode assembly 100 to a certain extent.

[0070] Optionally, the expansion element is an expansion tape, which is adhered to the protrusion 222 and expands upon contact with the electrolyte. It is conceivable that in other embodiments, the type of expansion element is not limited; any expansion element capable of expanding upon contact with the electrolyte is acceptable.

[0071] In other embodiments, the housing 300 is positively charged, and at least a portion of the protrusion 222 is folded towards the center of the electrode body 30 to cover the edge portion of the negative electrode tab 31b at that end. The difference between this embodiment and the embodiments described above lies in the electrical charge of the housing 300; the arrangement of other structures can refer to the arrangement in the embodiments described above, and will not be repeated here.

[0072] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0073] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. An electrode assembly, characterized in that, include: The electrode (10) and the diaphragm (20) are stacked and wound together to form an electrode body (30). Each layer of the diaphragm (20) includes a main body segment (21). The electrode body (10) and the main body segment (21) of the diaphragm (20) are stacked and wound together to form an electrode body (30). At least one end of the electrode body (30) in the axial direction has a tab (31) protruding from the main body segment (21). At least one of the diaphragms (20) includes a first extension (22) connected to the main body segment (21) thereto, the first extension (22) being wound around the electrode body (30) at least one turn; the first extension (22) having a protrusion (222) at its axial end protruding from the main body segment (21), at least a portion of the protrusion (222) being folded toward the side closer to the center of the electrode body (30) to cover the edge portion of the tab (31) at the corresponding end.

2. The electrode assembly according to claim 1, characterized in that, The electrode body (30) includes a body (32), and the electrode tab (31) at at least one end includes a transition portion (311) and an electrical connection portion (312), wherein the transition portion (311) is disposed between the electrical connection portion (312) and the body (32); The electrical connection portion (312) is bent toward the side closer to the center of the body (32) relative to the transition portion (311), and the portion of the protrusion (222) protruding from the transition portion (311) is folded toward the side closer to the center of the body (32) and covers the edge portion of the electrical connection portion (312).

3. The electrode assembly according to claim 1, characterized in that, The first extension segment (22) and its corresponding main body segment (21) are integrally formed; or The first extension segment (22) and its corresponding main body segment (21) are separately set and bonded together.

4. The electrode assembly according to claim 1, characterized in that, The electrode assembly has a circumference C, and the first extension (22) has a first length L1 along the winding direction, L1 = (1.5-4)C; and / or The first extension segment (22) is wound around the electrode body (30) 1.5-3 times.

5. The electrode assembly according to claim 1, characterized in that, The protrusion (222) has a first height Wb along the axial direction, where Wb = 10.5 mm - 18.5 mm; and / or The first extension segment (22) includes a main body portion (221) and the protrusion (222) connected to each other. The main body portion (221) is connected to the main body segment (21), and the protrusion (222) has a slit (2221) at one end away from the main body portion (221).

6. The electrode assembly according to claim 5, characterized in that, Each turn of the first extension (22) wound around the electrode body (30) has the cut (2221). and / or The height of the cut (2221) is less than the height of the protrusion (222).

7. The electrode assembly according to claim 1, characterized in that, All of the diaphragms (20) include the first extension (22), and the tails of all the diaphragms (20) are flush. or Part of the diaphragm (20) includes the first extension (22).

8. A single battery cell, characterized in that, Includes a collector plate (200) and an electrode assembly as described in any one of claims 1-7; The collector plate (200) is electrically connected to the corresponding tab (31), and the folded portion of the protrusion (222) also covers the end face of the collector plate (200) away from the electrode assembly.

9. The battery cell according to claim 8, characterized in that, The battery cell also includes a housing (300) and an insulating pad (400). The insulating pad (400) includes an insulating part (401) and a guide part (402) connected to each other. The insulating part (401) is disposed along the axial direction between the collector (200) and the end wall of the housing (300). The guide part (402) is connected to the edge of the insulating part (401) along the axial direction near the side of the collector (200). The guide portion (402) has an arc-shaped guide surface (4021) for guiding the first extension segment (22) to fold over and cover the end face of the collector plate (200) away from the electrode assembly.

10. The battery cell according to claim 9, characterized in that, The thickness of the first extension segment (22) is greater than the thickness of the main body segment (21); or The first extension segment (22) is made of a first material, and the main body segment (21) is made of a second material. The strength of the first material is greater than that of the second material.

11. The battery cell according to claim 9, characterized in that, The guide portion (402) has a first wall thickness W1 at one end away from the insulating portion (401) along the axial direction, and a second wall thickness W2 at the other end connected to the insulating portion (401). The electrode assembly has a first radius R1, and the collector plate (200) has a second radius R2, where R2 < R1. Wherein, W1 = 0.1 mm - 0.3 mm, and W2 - W1 - (R1 - R2) = 1 mm - 3 mm. and / or The protrusion (222) is provided with an expansion member that expands upon contact with electrolyte, and the expansion member is filled between the guide (402) and the electrode assembly.

12. The battery cell according to claim 8, characterized in that, The protrusion (222) covers the end face of the collector plate (200) and has a first dimension L2, 7mm≤L2≤15mm.

13. A battery, characterized in that, Includes the battery cell as described in any one of claims 8-12.

14. An electrical appliance, characterized in that, It includes the battery cell as described in any one of claims 8-12, or the battery as described in claim 13.

Images