Electrode sheet and design method therefor, electrode core, battery cell, battery assembly, and electric device

Abstract

An electrode sheet (20) and a design method therefor, an electrode core (10), a battery cell, a battery assembly, and an electric device. A winding trajectory of the electrode sheet (20) is a spiral line; the electrode sheet (20) comprises an electrode sheet body (21) and tabs (22); the tabs (22) are connected to one side of the electrode sheet body (21) in the width direction; a starting position of a tab (22) located at an nth turn is an nth starting position, Lxn is the winding length of the electrode sheet (20) from a winding starting position of the electrode sheet (20) to the nth starting position, and the following relation is satisfied: Ln-km*Ln≤Lxn≤Ln+kl*Ln, wherein Ln is as shown in formula I.

Description

Electrode sheets and their design methods, electrode cores, battery cells, battery modules and electrical equipment

[0001] Cross-reference to related applications

[0002] This application is based on and claims priority to Chinese Patent Application No. 2024112072930, filed on August 29, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of batteries, and in particular to an electrode sheet and its design method, an electrode core, a battery cell, a battery assembly, and an electrical device. Background Technology

[0004] In related technologies, tabless technology is used to improve the energy density of the battery core, which involves using the cell casing as a conductive component to lead out the negative electrode. However, this method results in a longer current flow path and increased internal resistance. Therefore, improvements are needed. Summary of the Invention

[0005] This application aims to at least solve one of the technical problems existing in the prior art. To this end, one object of this application is to provide an electrode sheet such that the winding length from the winding start position to the nth start position satisfies: L n -k m *L n ≤L xn ≤L n +k l *L n ,in The electrode core formed by winding this electrode sheet allows tabs of different polarities to be located at the same end of the electrode core during the winding process. The tabs of different polarities can be set separately along the radial direction of the electrode core, so that the tabs of the two electrodes do not overlap or interfere with each other after being flattened or flattened, thus avoiding short circuits inside the battery. Since the tabs of different polarities are located at the same end of the electrode core, the electrode core can have a high energy density, and it is also convenient to lead out the positive and negative electrodes of the electrode core from the same end. There is no need to use the cell shell as a conductive component, which can shorten the current flow path, reduce the internal resistance of the structure, and improve battery performance.

[0006] This application also proposes an electrode core comprising the aforementioned electrode sheets.

[0007] This application also proposes a battery cell including the aforementioned electrode core.

[0008] This application also proposes a battery assembly including the aforementioned battery cells.

[0009] This application also proposes an electrical device that includes the aforementioned battery assembly.

[0010] This application also proposes a method for designing electrode sheets.

[0011] According to the first aspect of the present application, an electrode sheet is used to wind to form an electrode core. The winding trajectory of the electrode sheet is a spiral. The electrode sheet includes an electrode sheet body and an electrode tab. The electrode tab is connected to one side of the electrode sheet body in the width direction.

[0012] The starting position of the pole piece located in the nth loop is the nth starting position, L xn L is the winding length of the electrode from the starting position of the winding to the nth starting position. n -k m *L n ≤L xn ≤L n +k l *L n ,in k m The starting position of the tab in the nth ring is the deviation coefficient when the thickness of the electrode plate reaches its maximum value within a set deviation range, k. l The starting position of the tab in the nth ring is the deviation coefficient when the thickness of the electrode plate is at its minimum within a set deviation range, 0≤k. m ≤6%, 0≤k l ≤6%, the formula for the spiral is: R n =θ*ε n θ = t0 / 2π, where t0 is the thickness of the winding unit that forms the electrode core, and the winding unit includes the stacked electrode sheets and diaphragm. R n L is the radius of the pole core at the nth revolution. c The pre-winding length of the diaphragm in the winding unit before the electrode is wound.

[0013] According to the embodiments of this application, by ensuring that the winding length from the starting position of the electrode to the starting position of the nth turn of the tab satisfies the above-mentioned relationship, it is easy to separate the two tabs. Tabs of different polarities can be set separately along the radial direction of the electrode core, so that the tabs of the two electrodes do not overlap or interfere with each other after being flattened or flattened, thus avoiding short circuits inside the battery. Since the tabs of different polarities are located at the same end of the electrode core, the electrode core can have a high energy density, and it is also convenient to lead out the positive and negative electrodes of the electrode core from the same end. There is no need to use the cell shell as a conductive component, which can shorten the current flow path, reduce the internal resistance of the structure, and improve the battery performance.

[0014] According to some embodiments of this application, the winding unit includes stacked positive electrode plates, negative electrode plates, and two layers of the separator, wherein the diameter D of the electrode core at the nth turn is... n=D0+t3*4(n+i3)+t2*2(n+i2)+t1*2*n, t0=t1+t2+2t3, D0 is the diameter of the central hole of the electrode core, t1 is the thickness of the positive electrode sheet, t2 is the thickness of the negative electrode sheet, t3 is the thickness of the single-layer separator, i3 is the number of pre-wound turns of the separator before the positive electrode sheet is wound, and i2 is the number of pre-wound turns of the negative electrode sheet before the positive electrode sheet is wound.

[0015] According to some embodiments of this application, the height of the electrode tab in the width direction of the electrode body is the electrode tab height, and the height of the electrode tab in the first ring is h1, where h1 satisfies: 0 ≤ h1 ≤ 1 / 2D JR D JR The diameter of the electrode core is given.

[0016] According to some embodiments of this application, the electrode includes a plurality of tabs, which are connected to the same side in the width direction of the electrode body and are spaced apart along the length direction of the electrode body. The plurality of tabs of the same polarity are arranged sequentially along the radial direction of the electrode core.

[0017] According to some embodiments of this application, the distance between the electrode tab of the (n+1)th turn and the electrode tab of the nth turn in the electrode sheet unfolded state is d. n The distance between the center of the electrode tab and the center of the electrode core in the (n+1)th turn is greater than the distance between the center of the electrode tab and the center of the electrode core in the nth turn. The spacing d between adjacent electrode tabs is greater in the direction from the starting position of the electrode winding to the ending position of the electrode winding. n Increase sequentially.

[0018] According to some embodiments of this application, on the electrode core, the line connecting the starting positions of the plurality of electrode tabs is a straight line extending radially along the electrode core.

[0019] According to some embodiments of this application, on the electrode core, the line connecting the end positions of the plurality of electrode tabs is a straight line extending radially along the electrode core.

[0020] According to some embodiments of this application, the height of the tab in the width direction of the electrode body is the tab height, the tab height of the (n+1)th turn is not greater than the tab height of the nth turn, and the distance between the tab of the (n+1)th turn and the center of the electrode core is greater than the distance between the tab of the nth turn and the center of the electrode core.

[0021] According to some embodiments of this application, the difference between the electrode height of the (n+1)th electrode and the electrode height of the nth electrode is h. c h c Satisfy: t0≤h c ≤5t0.

[0022] According to some embodiments of this application, 1 / 4πD n ≤A n ≤1 / 2πD n D n Let A be the diameter of the pole core at the nth revolution. n The length of the nth loop of the electrode tab along the length direction of the electrode body when the electrode is in the unfolded state.

[0023] According to a second aspect embodiment of the present application, the electrode core is formed by winding a winding unit. The winding trajectory of the winding unit is a spiral. The winding unit includes a stacked first electrode, a second electrode, and a diaphragm. The first electrode and the second electrode have opposite polarities. At least one of the first electrode and the second electrode is an electrode according to a first aspect embodiment of the present application. The diaphragm is provided between the first electrode and the second electrode. The first electrode includes a first electrode body and a first electrode tab connected to one side of the first electrode body. The first electrode tab constitutes a first electrode tab portion. The second electrode includes a second electrode body and a second electrode tab connected to one side of the second electrode body. The second electrode tab constitutes a second electrode tab portion. The first electrode tab portion and the second electrode tab portion are located at the same end of the electrode core in the axial direction of the electrode core. The first electrode tab portion and the second electrode tab portion are opposite to each other and spaced apart along the radial direction of the electrode core.

[0024] According to the embodiments of this application, the battery cell is formed by winding the electrode sheet, which includes the electrode sheet of the first aspect of this application. During the winding process, the tabs of different polarities can be located at the same end of the electrode core to facilitate the separation of the two tabs. The tabs of different polarities can be set separately along the radial direction of the electrode core, so that the tabs of the two poles do not overlap or interfere with each other after being flattened or flattened, thus avoiding short circuits inside the battery. Since the tabs of different polarities are located at the same end of the electrode core, the electrode core can have a high energy density, and it is also convenient to lead the positive and negative poles of the electrode core out from the same end. There is no need to use the cell shell as a conductive component, which can shorten the current flow path, reduce the internal resistance of the structure, and improve the battery performance.

[0025] According to the embodiment of this application, the sum of the arc value of the first electrode ear and the arc value of the second electrode ear ranges from π to 2π.

[0026] A battery cell according to a third aspect of this application includes: an electrode core according to a second aspect of this application.

[0027] The battery cell according to the embodiments of this application, by including the electrode core according to the second aspect of the embodiment of this application, has a high energy density and also facilitates the lead-out of the positive and negative electrodes of the electrode core from the same end, without the need to use the cell casing as a conductive component, which can shorten the current flow path, reduce the internal resistance of the structure, and improve battery performance.

[0028] A battery assembly according to a fourth aspect of this application includes: a battery cell according to a third aspect of this application.

[0029] The battery assembly according to the embodiments of this application includes a battery cell according to the third aspect of the embodiments of this application. The battery cell has a high energy density and also facilitates the lead-out of the positive and negative electrodes from the same end. It does not require the battery cell casing to be used as a conductive component, which can shorten the current flow path, reduce the internal resistance of the structure, and improve the battery performance.

[0030] An electrical device according to a fifth aspect of this application includes a battery assembly according to a fourth aspect of this application.

[0031] The electrical device according to the embodiments of this application, by including the battery according to the third aspect of the embodiment of this application, has a high energy density in the core and also facilitates the positive and negative electrodes of the core to be led out from the same end, without having to use the cell casing as a conductive component, which can shorten the current flow path, reduce the internal resistance of the structure, and improve the battery performance.

[0032] According to the electrode design method of the sixth aspect of this application, the electrode is used to wind to form an electrode core, the electrode core is wound by a winding unit, the winding trajectory of the electrode or the electrode core is a spiral, the winding unit includes the stacked electrode and a diaphragm, the electrode includes an electrode body and an electrode tab, and the electrode tab is connected to one side of the electrode body in the width direction.

[0033] The design method of the electrode includes: based on the thickness t0 of the winding unit and the diameter D of the electrode core at the nth turn... n The pre-wound length L of the diaphragm in the winding unit before the electrode is wound. c The starting position of the tab in the nth turn is determined by the thickness deviation of the electrode sheet.

[0034] According to the electrode design method of this application embodiment, the electrode is designed based on the thickness t0 of the winding unit and the diameter D of the winding unit at the nth turn. n And the length A of the tab of the nth ring along the length direction of the electrode body when the electrode is in the unfolded state. n Determine d nDuring the winding process, tabs of different polarities can be located at the same end of the electrode core. Tabs of different polarities can be set separately along the radial direction of the electrode core, so that the tabs of the two poles do not overlap or interfere with each other after being flattened or flattened, thus avoiding short circuits inside the battery. Since tabs of different polarities are located at the same end of the electrode core, the electrode core can have a high energy density, and it is also convenient to lead out the positive and negative poles of the electrode core from the same end. There is no need to use the cell shell as a conductive component, which can shorten the current flow path, reduce the internal resistance of the structure, and improve battery performance.

[0035] According to some embodiments of this application, the starting position of the electrode tab in the nth turn is the nth starting position, L xn L is the winding length of the electrode from the starting position of the winding to the nth starting position. n -k m *L n ≤L xn ≤L n +k l *L n ,in k m The starting position of the tab in the nth ring is the deviation coefficient when the thickness of the electrode plate reaches its maximum value within a set deviation range, k. l The starting position of the tab in the nth turn is the deviation coefficient when the thickness of the electrode sheet is at its minimum within a set deviation range. The formula for the spiral is: R n =θ*ε n , θ=t0 / 2π.

[0036] According to some embodiments of this application, k m =(L n -L nm ) / (π*D n ), k l =(L nl -L n ) / (π*D n ), L nm When the thickness of the electrode sheet is at its maximum value within a set deviation range, the winding length L of the electrode sheet from the winding start position to the nth starting position is... nl When the thickness of the electrode sheet is at its minimum within a set deviation range, the winding length of the electrode sheet from the starting position of the winding to the nth starting position.

[0037] According to some embodiments of this application, 0≤k m ≤6%, 0≤k l ≤6%.

[0038] According to some embodiments of this application, the winding unit includes stacked positive electrode plates, negative electrode plates, and two layers of the separator, wherein the diameter D of the electrode core at the nth turn is... n =D0+t3*4(n+i3)+t2*2(n+i2)+t1*2*n, t0=t1+t2+2t3, D0 is the diameter of the central hole of the electrode core, t1 is the thickness of the positive electrode sheet, t2 is the thickness of the negative electrode sheet, t3 is the thickness of the single-layer separator, i3 is the number of pre-wound turns of the separator before the positive electrode sheet is wound, and i2 is the number of pre-wound turns of the negative electrode sheet before the positive electrode sheet is wound.

[0039] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0040] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0041] Figure 1 is a perspective view of an electrode core according to some embodiments of the present application, wherein the first electrode tab and the second electrode tab are separately flattened and respectively form the first electrode tab portion and the second electrode tab portion;

[0042] Figure 2 is a top view of the pole core in Figure 1;

[0043] Figure 3 is a cross-sectional view of the pole core in Figure 1;

[0044] Figure 4 is an enlarged view of point B in Figure 3;

[0045] Figure 5 is a schematic diagram of the first and second electrode tabs of the electrode core in Figure 1 before they are kneaded.

[0046] Figure 6 is a perspective view of an electrode core according to some other embodiments of the present application, wherein the first electrode tab and the second electrode tab are flattened separately and respectively form the first electrode tab portion and the second electrode tab portion;

[0047] Figure 7 is a top view of the pole core in Figure 6;

[0048] Figure 8 is a schematic diagram of the first and second tabs of the electrode core in Figure 6 when they are not photographed.

[0049] Figure 9 is a schematic diagram of the electrode sheet in an unfolded state according to some embodiments of this application.

[0050] Reference numerals: 10, pole core; 11, winding unit; 12, first pole piece; 13, second pole piece; 14, diaphragm; 17, first pole tab; 18, second pole tab; 20, pole piece; 21, pole piece body; 22, pole tab. Detailed Implementation

[0051] 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 are only used to explain this application, and should not be construed as limiting this application.

[0052] The electrode 20 according to an embodiment of this application is described below with reference to Figures 1-9.

[0053] According to the first aspect of this application, the electrode 20 is used to wind and form an electrode core 10. The winding trajectory of the electrode 20 is a spiral. The electrode 20 includes an electrode body 21 and an electrode tab 22, with the electrode tab 22 connected to one side of the electrode body 21 in the width direction. The winding trajectory of the electrode 20 refers to the trajectory of the moving point of the electrode 20 around the rotation axis, i.e., the winding needle, gradually moving away from the winding needle.

[0054] For example, the electrode 20 includes a plurality of tabs 22, which are spaced apart along the length of the electrode body 21.

[0055] For example, a spiral can be an Archimedean spiral.

[0056] The starting position of the pole lug 22 located in the nth ring is the nth starting position, L xn L is the winding length of electrode 20 from the starting position of winding electrode 20 to the nth starting position. n -k m *L n ≤L xn ≤L n +k l *L n ,in k m k is the deviation coefficient for the starting position of the tab 22 in the nth ring when the thickness of the electrode 20 is at its maximum value within the set deviation range. l This is the deviation coefficient for the starting position of the tab 22 in the nth ring when the thickness of the electrode 20 is at its minimum within the set deviation range, where 0 ≤ k. m ≤6%, 0≤k l ≤6%, the formula for the spiral is: R n =θ*ε n θ = t0 / 2π, where t0 is the thickness of the winding unit 11 that forms the electrode core 10. The winding unit 11 includes stacked electrode sheets 20 and diaphragm 14. R n Let L be the radius of the pole core 10 at the nth ring. c θ represents the pre-winding length of the diaphragm 14 in the winding unit 11 before the electrode 20 is wound. Here, θ is the arc parameter, and ε is the rotational radius. nLet L be the total angle of the winding rotation of electrode 20 in the nth turn. This is determined by the winding length L of electrode 20 from its initial winding position to the nth starting position. xn Satisfy L n -k m *L n ≤L xn ≤L n +k l *L n ,in After the electrode sheet 20 is wound, the tabs 22 of the same electrode can be arranged sequentially along the radial direction of the winding unit 11. This allows the tabs 22 of the same electrode to be concentrated in a portion of one side of the winding unit 11, leaving sufficient space for the tabs 22 of the other electrode to facilitate separation of the tabs 22. When the winding unit 11 includes a positive electrode sheet 20 and a negative electrode sheet 20, the positive tabs 22 can be concentrated in a portion of one side of the winding unit 11, and the negative tabs 22 can be concentrated in another portion of the same side of the winding unit 11. This ensures that the areas where the positive and negative tabs 22 are arranged do not overlap, separating the areas where the positive and negative tabs 22 are arranged and preventing contact between the positive and negative tabs 22 that could cause a short circuit inside the battery.

[0057] For example, the diaphragm 14 in the winding unit 11 is pre-wound 1 to 3 times before the electrode 20 is wound.

[0058] According to the embodiments of this application, the electrode 20, by ensuring that the winding length from the starting position of the electrode 20 to the starting position of the nth turn of the tab 22 satisfies the above-mentioned relationship, facilitates the separation of the two tabs 22. Tabs 22 with different polarities can be arranged separately along the radial direction of the electrode core, so that the tabs 22 of the two poles do not overlap or interfere with each other after being flattened or flattened, avoiding internal short circuits in the battery. Since the tabs 22 with different polarities are located at the same end of the electrode core 10, the electrode core 10 can have a high energy density, and it is also convenient to lead the positive and negative electrodes of the electrode core 10 out from the same end, without having to use the cell casing as a conductive component, which can shorten the current flow path, reduce the internal resistance of the structure, and improve battery performance.

[0059] According to some embodiments of this application, the winding unit 11 includes stacked positive electrode 20, negative electrode 20, and two layers of separator 14, and the diameter D of the electrode core 10 at the nth turn is... n=D0 + t3*4(n+i3) + t2*2(n+i2) + t1*2*n, t0 = t1 + t2 + 2t3, D0 is the diameter of the center hole of the electrode core 10, t1 is the thickness of the positive electrode 20, t2 is the thickness of the negative electrode 20, t3 is the thickness of the single-layer separator 14, i3 is the number of pre-wound turns of the separator 14 before the positive electrode 20 is wound, and i2 is the number of pre-wound turns of the negative electrode 20 before the positive electrode 20 is wound. Generally, the separator 14 is wound more turns than the positive electrode 20, and the negative electrode 20 is wound more than half a turn than the positive electrode 20. Therefore, generally, at the same position of the winding unit 11, the winding length of the winding unit 11 is greater than the winding length of the electrode 20. For example, in the process of winding the unit to form the electrode core 10, the separator 14 is wound 1 to 3 turns first, then half a turn of the negative electrode plate 20 is wound, and then the separator 14, the negative electrode plate 20 and the positive electrode plate 20 are wound together. n The winding length of the winding unit 11 at the nth starting position refers to the winding length of the winding unit 11 from the starting winding position of the diaphragm 14 to the nth starting position.

[0060] According to some embodiments of this application, the height of the tab 22 in the width direction of the electrode body 21 is the height of the tab 22, and the height of the tab 22 in the first ring is h1, where h1 satisfies: 0 ≤ h1 ≤ 1 / 2D JR D JR The diameter is the diameter of the pole core 10. This is achieved by ensuring that the height h of the first turn of the pole tab 22 is no greater than half the diameter D of the winding unit 11. JR This can prevent the tab 22 of the first turn from being too high, which would cause the tab 22 to extend beyond the winding unit 11 and interfere with the cell housing after the tab 22 is flattened or patted. By limiting the upper limit of the height of the tab 22 of the first turn, the winding unit 11 can be smoothly assembled into the cell housing.

[0061] According to some embodiments of this application, the electrode 20 includes a plurality of tabs 22. The plurality of tabs 22 are connected to the same side in the width direction of the electrode body 21 and are spaced apart along the length direction of the electrode body 21. The plurality of tabs 22 of the same polarity are arranged sequentially along the radial direction of the electrode core 10. By arranging the plurality of tabs 22 of the same polarity sequentially along the radial direction of the electrode core 10 on the winding unit 11, the tabs 22 of the same polarity can be concentrated in a part of one side of the electrode body 21, which is convenient for positioning. Since the multiple tabs 22 of the same polarity electrode 20 are spaced apart and the winding length from the starting position of the winding of the electrode 20 to the starting position of the nth turn of the tab 22 satisfies the above relationship, during the winding process, the interval between two adjacent tabs 22 of the same polarity electrode 20 can reserve sufficient distribution space for the tabs 22 of the other polarity, so as to facilitate the separation of the two tabs 22. The tabs 22 of different polarities can be set separately along the radial direction of the wound electrode core 10, so that the tabs 22 of the two poles do not overlap or interfere with each other after being flattened or flattened, thus avoiding short circuit inside the battery.

[0062] According to some embodiments of this application, the distance between the (n+1)th loop electrode tab 22 and the nth loop electrode tab 22 in the unfolded state of the electrode plate 20 is d. n The distance between the center of the tab 22 in the (n+1)th turn and the center of the core 10 is greater than the distance between the tab 22 in the nth turn and the center of the core 10. In the direction from the starting position of the winding of the electrode 20 (refer to the starting position g1 in the diagram) to the ending position of the winding of the electrode 20 (refer to the ending position g2 in the diagram), the spacing d between adjacent tabs 22 is... n The spacing d between adjacent tabs 22 is increased sequentially. This is achieved by increasing the spacing d in the direction from the starting position of the winding of the electrode body 21 to the ending position of the winding of the electrode body 21. n By increasing the size sequentially, the tabs 22 of the same pole can be concentrated in a part of one side of the electrode body 21 after winding, which facilitates the separation of the distribution positions of the positive electrode tabs 22 and the negative electrode tabs 22.

[0063] According to some embodiments of this application, on the electrode core 10, the line connecting the starting positions of multiple tabs 22 is a straight line extending radially along the electrode core 10. By making the line connecting the starting positions of multiple tabs 22 on the electrode core 10 a straight line extending radially along the electrode core 10, the tabs 22 of the same electrode can be concentrated in a part of one side of the electrode body 21, which is convenient for positioning.

[0064] According to some embodiments of this application, on the electrode core 10, the line connecting the end positions of the plurality of tabs 22 is a straight line extending radially along the electrode core 10. By making the line connecting the end positions of the plurality of tabs 22 on the electrode core 10 a straight line extending radially along the electrode core 10, overlapping positions of tabs 22 of different electrodes can be avoided.

[0065] According to some embodiments of this application, the height of the tab 22 in the width direction of the electrode body 21 is the height of the tab 22. The height of the tab 22 in the (n+1)th turn is not greater than the height of the tab 22 in the nth turn. The distance between the tab 22 in the (n+1)th turn and the center of the electrode core 10 is greater than the distance between the tab 22 in the nth turn and the center of the electrode core 10. By ensuring that the height of the tab 22 in the (n+1)th turn is not greater than the height of the tab 22 in the nth turn, excessive height of the tab 22 can be avoided. After the tab 22 is flattened or patted flat along the radial direction from the inside to the outside, the tab 22 extends beyond the winding unit 11 and interferes with the assembly shell of the electrode core 10, allowing the electrode core 10 to be smoothly assembled with other components.

[0066] According to some embodiments of this application, the difference between the height of the electrode 22 in the (n+1)th ring and the height of the electrode 22 in the nth ring is h. c h c Satisfy: t0≤h c ≤5t0. After the tabs 22 are flattened or patted flat, there can be a large overlap area between adjacent tabs 22, resulting in a large flow capacity.

[0067] According to some embodiments of this application, 1 / 4πD n ≤A n ≤1 / 2πD n D n Let A be the diameter of the pole core 10 at the nth ring. n Let be the length of the nth loop of electrode tab 22 along the length direction of electrode body 21 when electrode plate 20 is in the unfolded state. This is achieved by ensuring that the length of the nth loop of electrode tab 22 along the length direction of electrode body 21 when electrode plate 20 is in the unfolded state is not less than 1 / 4πD. n This avoids the tab 22 being too short in the circumferential direction of the winding unit 11, which would result in the tab 22 being too small, and can improve the current carrying capacity of the tab 22; by ensuring that the length of the tab 22 in the nth turn along the length direction of the electrode body 21 in the unfolded state of the electrode 20 is no greater than 1 / 2πD n To avoid the overlap between the positive and negative electrode tabs 22, which could easily cause short circuits, the tabs 22 on a single electrode 20 are concentrated and sufficient space is reserved for the tabs 22 on the other electrode 20, thus separating the distribution of the tabs 22 on the two electrode 20 and ensuring battery safety.

[0068] According to the second aspect embodiment of the present application, the electrode core 10 is formed by winding a winding unit 11. The winding trajectory of the winding unit 11 is a spiral. The winding unit 11 includes a stacked first electrode 12, a second electrode 13, and a diaphragm 14. The first electrode 12 and the second electrode 13 have opposite polarities. At least one of the first electrode 12 and the second electrode 13 is an electrode 20 according to the first aspect embodiment of the present application. A diaphragm 14 is provided between the first electrode 12 and the second electrode 13. The first electrode 12 includes a first electrode 13. The first electrode body 21 and the first electrode tab 22 connected to one side of the first electrode body 21 constitute the first electrode tab portion 17. The second electrode 13 includes the second electrode body 21 and the second electrode tab 22 connected to one side of the second electrode body 21. The second electrode tab 22 constitutes the second electrode tab portion 18. The first electrode tab portion 17 and the second electrode tab portion 18 are located at the same end of the electrode core 10 in the axial direction of the electrode core 10. The first electrode tab portion 17 and the second electrode tab portion 18 are arranged opposite each other and spaced apart along the radial direction of the electrode core 10.

[0069] According to the embodiments of this application, the electrode core 10 is formed by winding the electrode sheet 20, which is included in the first aspect of the embodiment of this application. During the winding process, the tabs 22 of different polarities can be located at the same end of the electrode core 10. In this way, during the winding process, the tabs 22 of different polarities can be set separately along the radial direction of the electrode core 10, so that the tabs 22 of the two poles do not overlap or interfere with each other after being flattened or flattened, thus avoiding internal short circuits in the battery. Since the tabs 22 of different polarities are located at the same end of the electrode core 10, the electrode core 10 can have a high energy density, and it is also convenient to lead out the positive and negative poles of the electrode core 10 from the same end. There is no need to use the electrode core 10 shell as a conductive component, which can shorten the current flow path, reduce the internal resistance of the structure, and improve battery performance.

[0070] According to the embodiment of this application, the sum of the arc values ​​of the first tab 17 and the second tab 18 in the electrode core 10 ranges from π to 2π. By ensuring that the sum of the arc values ​​of the first tab 17 and the second tab 18 is not less than 2π, it is possible to avoid the first tab 22 and the second tab 22 being too short in the circumferential direction of the winding unit 11, resulting in the tab 22 being too small and having poor current carrying capacity and low performance. This allows the length of the tab 22 to be large enough to improve battery performance. By ensuring that the sum of the arc values ​​of the first tab 17 and the second tab 18 is not greater than π, it is possible to avoid the overlapping of the distribution positions of the first tab 17 and the second tab 18. After flattening or patting, the first tab 17 and the second tab 18 may come into contact and cause a short circuit, thus ensuring battery safety.

[0071] A battery cell according to a third aspect of this application includes: an electrode core 10 according to a second aspect of this application.

[0072] The battery cell according to the embodiments of this application includes the electrode core 10 according to the second aspect of this application. The electrode core 10 has a high energy density and also facilitates the lead-out of the positive and negative electrodes of the electrode core 10 from the same end. It does not require the electrode core 10 shell to be used as a conductive component, which can shorten the current flow path, reduce the internal resistance of the structure, and improve the battery performance.

[0073] A battery assembly according to a fourth aspect of this application includes: a battery cell according to a third aspect of this application.

[0074] The battery assembly according to the embodiments of this application includes a battery cell according to the third aspect of the embodiments of this application. The electrode core 10 in the battery cell has a high energy density and also facilitates the positive and negative electrodes of the electrode core 10 to be led out from the same end. There is no need to use the shell of the electrode core 10 as a conductive component. This can shorten the current flow path, reduce the internal resistance of the structure, and improve the battery performance.

[0075] An electrical device according to a fifth aspect of this application includes a battery assembly according to a fourth aspect of this application.

[0076] According to the embodiments of this application, the electrical device includes a battery according to the third aspect of this application. The battery core 10 has a high energy density and also facilitates the positive and negative electrodes of the core 10 to be led out from the same end. It does not require the core 10 shell to be used as a conductive component, which can shorten the current flow path, reduce the internal resistance of the structure, and improve the battery performance.

[0077] According to the design method of the electrode 20 according to the sixth aspect of the present application, the electrode 20 is used to wind to form the electrode core 10. The electrode core 10 is wound by the winding unit 11. The winding trajectory of the electrode 20 or the electrode core 10 is a spiral. The winding unit 11 includes stacked electrode 20 and diaphragm 14. The electrode 20 includes electrode body 21 and electrode tab 22. The electrode tab 22 is connected to one side of the electrode body 21 in the width direction.

[0078] The design method of electrode 20 includes: based on the thickness t0 of the winding unit 11 and the diameter D of the electrode core 10 at the nth turn. n The pre-wound length L of the diaphragm 14 in the winding unit 11 before the electrode 20 is wound. c The starting position of the tab 22 in the nth turn is determined by the thickness deviation of the electrode 20. For example, the number of pre-wound turns of the diaphragm 14 in the winding unit 11 before winding the electrode 20 is 1 to 3.

[0079] According to the design method of the electrode 20 in the embodiments of this application, the thickness t0 of the winding unit and the diameter D of the winding unit 11 at the nth turn are used to design the electrode 20. n And the length A of the nth loop of the electrode tab 22 along the length direction of the electrode body 21 when the electrode 20 is in the unfolded state.n Determine d n During the winding process, tabs 22 of different polarities can be located at the same end of the electrode core 10. These tabs 22 can be arranged radially apart along the electrode core 10, ensuring that the tabs 22 do not overlap or interfere with each other after being flattened or rolled, thus preventing internal short circuits in the battery. Because the tabs 22 of different polarities are located at the same end of the electrode core 10, the electrode core 10 can achieve a high energy density, and it is also convenient to lead the positive and negative electrodes of the electrode core 10 out from the same end. This eliminates the need for the electrode core 10 casing to be a conductive component, shortening the current flow path, reducing structural internal resistance, and improving battery performance.

[0080] According to some embodiments of this application, the starting position of the tab 22 of the nth turn is the nth starting position, L xn L is the winding length of electrode 20 from the starting position of winding electrode 20 to the nth starting position. n -k m *L n ≤L xn ≤L n +k l *L n ,in k m k is the deviation coefficient for the starting position of the tab 22 in the nth ring when the thickness of the electrode 20 is at its maximum value within the set deviation range. l This is the deviation coefficient for the starting position of the tab 22 in the nth turn when the thickness of the electrode 20 is at its minimum within a set deviation range. For example, the set deviation range is ±2μm. The formula for the spiral is: R n =θ*ε n θ = t0 / 2π. By ensuring that the winding length of the winding unit 11 at the nth starting position satisfies L n -k m *L n ≤L xn ≤L n +k l *L n ,in After the electrode sheet 20 is wound, the tabs 22 of the same electrode are arranged sequentially along the radial direction of the winding unit 11. This allows the tabs 22 of the same electrode to be concentrated in a portion of one side of the winding unit 11, leaving sufficient space for the tabs 22 of the other electrode to be separated. When the winding unit 11 includes a positive electrode sheet 20 and a negative electrode sheet 20, the positive tabs 22 can be concentrated in a portion of one side of the winding unit 11, and the negative tabs 22 can be concentrated in another portion of the same side of the winding unit 11. This ensures that the areas where the positive and negative tabs 22 are arranged do not overlap, allowing the areas where the positive and negative tabs 22 are arranged to be separated, thus preventing the positive and negative tabs 22 from contacting each other and causing a short circuit inside the battery. This design allows for the calculation of the starting position of the tab 22 in the nth turn. This ensures that the starting position of the tab 22 in the nth turn is located at the pre-designed position during the winding process of the electrode 20, thereby guaranteeing the winding quality of the electrode 20 in subsequent winding processes.

[0081] By ensuring that the winding length of the winding unit 11 at the nth starting position satisfies L n -k m *L n ≤L xn ≤L n +k l *L n This can reduce the impact of thickness fluctuations in the positive or negative electrode 20 on the die-cutting position of the tab 22, thereby making the die-cutting position of the tab 22 more accurate.

[0082] According to some embodiments of this application, k m =(L n -L nm ) / (π*D n ), k l =(L nl -L n ) / (π*D n ), L nm When the thickness of electrode 20 is at its maximum value within the set deviation range, the winding length of electrode 20 from the winding start position to the nth starting position is L. nl When the thickness of electrode 20 is at its minimum within a set deviation range, the winding length of electrode 20 from its winding start position to the nth starting position. Where L... nm L can be calculated from the above. n The formula is used to calculate L. nm In the formula, t0 represents the thickness of the winding unit 11 when the thickness of the electrode 20 reaches its maximum value within the set deviation range; L nl L can be calculated from the above. nThe formula is used to calculate L. nl In the formula, t0 is the thickness of the winding unit 11 when the thickness of the electrode 20 is at its minimum within the set deviation range.

[0083] According to some embodiments of this application, 0≤k m ≤6%, 0≤k l ≤6%. Based on the different thicknesses and different incoming electrode sheets 20 used in the actual production process, it can be calculated that the deviation coefficient of the starting position of the nth loop electrode tab 22 is basically less than 6%. This makes the above formula basically applicable to the incoming electrode sheets 20 used in the production process.

[0084] According to some embodiments of this application, the winding unit 11 includes stacked positive electrode 20, negative electrode 20, and two layers of separator 14, and the diameter D of the electrode core 10 at the nth turn is... n =D0+t3*4(n+i3)+t2*2(n+i2)+t1*2*n, t0=t1+t2+2t3, D0 is the diameter of the central hole of the core 10, t1 is the thickness of the positive electrode 20, t2 is the thickness of the negative electrode 20, t3 is the thickness of the single-layer separator 14, i3 is the number of pre-wound turns of the separator 14 before the positive electrode 20 is wound, and i2 is the number of pre-wound turns of the negative electrode 20 before the positive electrode 20 is wound.

[0085] In actual production, the diameter of the center hole of the pole core 10 cannot be measured before the winding unit 11 is wound. Since the winding unit 11 is wound on the winding needle, the diameter of the winding needle is basically the same as the diameter of the center hole of the core. The diameter D0 of the center hole of the pole core 10 can be obtained by measuring the diameter of the winding needle.

[0086] In actual production, the thickness of the positive electrode 20, the thickness of the negative electrode 20, the thickness of the separator 14, and the diameter of the winding needle are all known. Based on the thickness of the positive electrode 20, the thickness of the negative electrode 20, the thickness of the separator 14, and the diameter of the winding needle, the thickness t0 of the winding unit 11 can be easily obtained.

[0087] 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.

[0088] In the description of this invention, "first feature" and "second feature" may include one or more of the features.

[0089] In the description of this invention, "a plurality of" means two or more.

[0090] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0091] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. An electrode sheet, wherein, Used for winding to form an electrode core, the winding trajectory of the electrode sheet is a spiral, the electrode sheet includes an electrode sheet body and an electrode tab, the electrode tab being connected to one side of the electrode sheet body in the width direction; The starting position of the pole piece located in the nth loop is the nth starting position, L xn L is the winding length of the electrode from the starting position of the winding to the nth starting position. n -k m *L n ≤L xn ≤L n +k l *L n ,in k m The starting position of the tab in the nth ring is the deviation coefficient when the thickness of the electrode plate reaches its maximum value within a set deviation range, k. l The starting position of the tab in the nth ring is the deviation coefficient when the thickness of the electrode plate is at its minimum within a set deviation range, 0≤k. m ≤6%, 0≤k l ≤6%, the formula for the spiral is: R n =θ*ε n θ = t0 / 2π, where t0 is the thickness of the winding unit that forms the electrode core, and the winding unit includes the stacked electrode sheets and diaphragm. R n L is the radius of the pole core at the nth revolution. c The pre-wound length of the diaphragm in the winding unit before the electrode is wound.

2. The electrode according to claim 1, wherein, The winding unit includes stacked positive electrode plates, negative electrode plates, and two layers of the separator, and the diameter D of the electrode core at the nth turn is... n =D0+t3*4(n+i3)+t2*2(n+i2)+t1*2*n, t0=t1+t2+2t3, D0 is the diameter of the central hole of the electrode core, t1 is the thickness of the positive electrode sheet, t2 is the thickness of the negative electrode sheet, t3 is the thickness of the single-layer separator, i3 is the number of pre-wound turns of the separator before the positive electrode sheet is wound, and i2 is the number of pre-wound turns of the negative electrode sheet before the positive electrode sheet is wound.

3. The electrode according to claim 1 or 2, wherein, The height of the electrode tab in the width direction of the electrode body is the electrode tab height. The height of the electrode tab in the first ring is h1, and h1 satisfies: 0 ≤ h1 ≤ 1 / 2D JR D JR The diameter of the electrode core is given.

4. The electrode according to any one of claims 1-3, wherein, The electrode includes a plurality of tabs, which are connected to the same side in the width direction of the electrode body and are spaced apart along the length direction of the electrode body. The plurality of tabs of the same polarity are arranged sequentially along the radial direction of the electrode core.

5. The electrode according to claim 4, wherein, The distance between the electrode tab of the (n+1)th ring and the electrode tab of the nth ring in the unfolded state of the electrode sheet is d. n The distance between the center of the electrode tab and the center of the electrode core in the (n+1)th turn is greater than the distance between the center of the electrode tab and the center of the electrode core in the nth turn. The spacing d between adjacent electrode tabs is greater in the direction from the starting position of the electrode winding to the ending position of the electrode winding. n Increase sequentially.

6. The electrode according to claim 4, wherein, On the pole core, the line connecting the starting positions of the plurality of pole tabs is a straight line extending radially along the pole core.

7. The electrode according to claim 6, wherein, On the pole core, the line connecting the end positions of the plurality of pole tabs is a straight line extending radially along the pole core.

8. The electrode according to any one of claims 1-7, wherein, The height of the tab in the width direction of the electrode body is the tab height. The tab height of the (n+1)th turn is not greater than the tab height of the nth turn. The distance between the tab in the (n+1)th turn and the center of the electrode core is greater than the distance between the tab in the nth turn and the center of the electrode core.

9. The electrode according to claim 8, wherein, The difference between the electrode height of the (n+1)th loop and the electrode height of the nth loop is h. c h c Satisfy: t0≤h c ≤5t0.

10. The electrode according to any one of claims 1-9, wherein, 1 / 4πD n ≤A n ≤1 / 2πD n D n Let A be the diameter of the pole core at the nth revolution. n The length of the nth loop of the electrode tab along the length direction of the electrode body when the electrode is in the unfolded state.

11. A type of electrode core, wherein, The electrode core is formed by winding a spiral unit. The winding unit includes a stacked first electrode, a second electrode, and a diaphragm. The first and second electrode have opposite polarities, and at least one of the first and second electrode is... According to any one of claims 1-10, the electrode sheet is provided with the diaphragm between the first electrode sheet and the second electrode sheet. The first electrode sheet includes a first electrode sheet body and a first electrode tab connected to one side of the first electrode sheet body, the first electrode tab forming a first electrode tab portion. The second electrode sheet includes a second electrode sheet body and a second electrode tab connected to one side of the second electrode sheet body, the second electrode tab forming a second electrode tab portion. The first electrode tab portion and the second electrode tab portion are located at the same end of the electrode core in the axial direction of the electrode core. The first electrode tab portion and the second electrode tab portion are arranged opposite to each other and spaced apart along the radial direction of the electrode core.

12. The electrode core according to claim 11, wherein, The sum of the arc value of the first electrode ear and the arc value of the second electrode ear ranges from π to 2π.

13. A single battery cell, wherein, include: The electrode core according to claim 11 or 12.

14. A battery assembly, wherein, include: The battery cell according to claim 13.

15. An electrical appliance, wherein, include: The battery assembly according to claim 14.

16. A method for designing an electrode, wherein, The electrode sheet is used to wind to form an electrode core, the electrode core is wound by a winding unit, the winding trajectory of the electrode sheet or the electrode core is a spiral, the winding unit includes stacked electrode sheets and diaphragms, the electrode sheet includes an electrode sheet body and an electrode tab, the electrode tab is connected to one side of the electrode sheet body in the width direction; The design method of the electrode includes: based on the thickness t0 of the winding unit and the diameter D of the electrode core at the nth turn... n The pre-wound length L of the diaphragm in the winding unit before the electrode is wound. c The starting position of the tab in the nth turn is determined by the thickness deviation of the electrode sheet.

17. The electrode design method according to claim 16, wherein, The starting position of the pole piece in the nth rotation is the nth starting position, L xn L is the winding length of the electrode from the starting position of the winding to the nth starting position. n -k m *L n ≤L xn ≤L n +k l *L n ,in k m The starting position of the tab in the nth ring is the deviation coefficient when the thickness of the electrode plate reaches its maximum value within a set deviation range, k. l The starting position of the tab in the nth turn is the deviation coefficient when the thickness of the electrode sheet is at its minimum within a set deviation range. The formula for the spiral is: R n =θ*ε n , θ=t0 / 2π.

18. The electrode design method according to claim 17, wherein, k m =(L n -L nm ) / (π*D n ), k l =(L nl -L n ) / (π*D n ), L nm When the thickness of the electrode sheet is at its maximum value within a set deviation range, the winding length L of the electrode sheet from the winding start position to the nth starting position is... nl When the thickness of the electrode sheet is at its minimum within a set deviation range, the winding length of the electrode sheet from the starting position of the winding to the nth starting position.

19. The electrode design method according to claim 17, wherein, 0≤k m ≤6%,0≤k l ≤6%。 20. The electrode design method according to claim 17, wherein, The winding unit includes stacked positive electrode plates, negative electrode plates, and two layers of the separator, and the diameter D of the electrode core at the nth turn is... n =D0+t3*4(n+i3)+t2*2(n+i2)+t1*2*n, t0=t1+t2+2t3, D0 is the diameter of the central hole of the electrode core, t1 is the thickness of the positive electrode sheet, t2 is the thickness of the negative electrode sheet, t3 is the thickness of the single-layer separator, i3 is the number of pre-wound turns of the separator before the positive electrode sheet is wound, and i2 is the number of pre-wound turns of the negative electrode sheet before the positive electrode sheet is wound.

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