Pole piece and design method thereof, pole core, battery monomer, battery assembly and electric equipment

Abstract

The invention discloses a pole piece and a design method thereof, a pole core, a battery monomer, a battery assembly and electric equipment, the winding track of the pole piece is a spiral line, the pole piece comprises a pole piece body and a pole lug, and the pole lug is connected to one side of the pole piece body in the width direction; the initial position of the tab located at the nth circle is the nth initial position, and Lxn is the winding length of the pole piece from the winding initial position of the pole piece to the nth initial position, and meets the following condition: Ln-km * Ln < = Lxn < = Ln + kl * Ln, the winding length from the winding initial position of the pole piece to the initial position of the tab of the nth circle meets the relational expression, so that separation of the tabs of the two poles is facilitated, the tabs of the two poles do not overlap and interfere with each other after being rubbed or flattened, and short circuit in the battery is avoided; and the pole core has relatively high energy density, and meanwhile, the positive electrode and the negative electrode of the pole core can be conveniently led out from the same end, so that the current flowing path can be shortened, and the battery performance is improved.

Description

Technical Field

[0001] The present invention relates to the field of batteries, and in particular to a pole piece and a design method thereof, a pole core, a battery cell, a battery assembly and an electrical device. Background Art

[0002] In the related art, in order to increase the energy density of the electrode core, the tab-free technology is adopted, that is, the battery cell shell is used as a conductive component to lead out the negative electrode. However, this method will cause the current to flow through a longer path and increase the internal resistance of the structure. Therefore, improvement is needed. Summary of the invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, one object of the present invention is to provide a pole piece, by making the winding length of the pole piece from the winding starting position to the nth starting position satisfy: L n -k m *L n ≤L xn ≤L n +k l *L n ,in By winding the pole piece to form the pole core, during the winding process, the pole ears with different polarities can be located at the same end of the pole core, and the pole ears with different polarities can be separately arranged along the radial direction of the pole core, so that the pole ears of the two poles do not overlap and interfere with each other after being flattened or patted, thereby avoiding internal short circuit of the battery. Since the pole ears with different polarities are located at the same end of the pole core, the pole core can have a higher energy density and it is also convenient to lead out the positive and negative poles of the pole core from the same end. There is no need to use the battery cell shell as a conductive component, which can shorten the current flow path, reduce the structural internal resistance, and improve battery performance.

[0004] The present invention also provides a pole core comprising the pole piece.

[0005] The present invention also provides a battery cell comprising the pole core.

[0006] The present invention also provides a battery assembly comprising the battery cell.

[0007] The present invention also provides an electrical device comprising the battery assembly.

[0008] The invention also proposes a pole piece design method.

[0009] The pole piece according to the first aspect of the present invention is used for winding to form a pole core, the winding track of the pole piece is a spiral line, the pole piece includes a pole piece body and a pole ear, and the pole ear is connected to one side of the pole piece body in the width direction;

[0010] The starting position of the pole ear located at the nth circle is the nth starting position, Lxn is the winding length of the pole piece from the winding starting position of the pole piece to the nth starting position, L n -k m *L n ≤L xn ≤L n +k l *L n ,in k m is the deviation coefficient of the starting position of the pole ear of the nth circle when the thickness of the pole piece takes the maximum value within the set deviation range, k l is the deviation coefficient of the starting position of the pole ear of the nth circle when the thickness of the pole piece takes the minimum value within the set deviation range, 0≤k m ≤6%, 0≤k l ≤6%, the formula of the spiral is: R n =θ*ε n , θ=t0 / 2π, t0 is the thickness of the winding unit wound to form the pole core, the winding unit includes the stacked pole pieces and diaphragms, R n is the radius of the pole core at the nth circle, L c It is the pre-winding length of the diaphragm in the winding unit before the pole piece is wound.

[0011] According to the pole piece of the embodiment of the present invention, by making the winding length from the starting position of the pole piece to the starting position of the pole ear of the nth turn satisfy the above relationship, it is convenient to separate the pole ears of the two poles, and the pole ears with different polarities can be separately arranged along the radial direction of the pole core, so that the pole ears of the two poles do not overlap and interfere with each other after being flattened or patted, thereby avoiding internal short circuit of the battery. Since the pole ears with different polarities are located at the same end of the pole core, the pole core can have a higher energy density and it is also convenient to lead out the positive and negative poles of the pole core from the same end. There is no need to use the battery cell shell as a conductive component, which can shorten the current flow path, reduce the structural internal resistance, and improve battery performance.

[0012] According to some embodiments of the present invention, the winding unit includes a stacked positive electrode sheet, a negative electrode sheet and two layers of the separator, and the diameter D of the electrode core at the nth turn is n =D0+t3*4+t2*2+t1*2*n, t0=t1+t2+2t3, D0 is the diameter of the center hole of the pole 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 diaphragm, i3 is the number of pre-winding turns of the diaphragm before the positive electrode sheet is wound, and i2 is the number of pre-winding turns of the negative electrode sheet before the positive electrode sheet is wound.

[0013] According to some embodiments of the present invention, the height of the pole ear in the width direction of the pole piece body is the pole ear height, and the height of the pole ear of the first circle is h1, and h1 satisfies: 0≤h1≤1 / 2D JR , D JR is the diameter of the pole core.

[0014] According to some embodiments of the present invention, the pole piece includes a plurality of pole ears, the plurality of pole ears are connected to the same side of the pole piece body in the width direction and are arranged at intervals along the length direction of the pole piece body, and the plurality of pole ears of the same polarity are arranged in sequence along the radial direction of the pole core.

[0015] According to some embodiments of the present invention, the distance between the pole lug of the n+1th circle and the pole lug of the nth circle when the pole piece is unfolded is d n , the distance between the pole ear of the n+1th circle and the center of the pole core is greater than the distance between the pole ear of the nth circle and the center of the pole core, and the spacing d between adjacent pole ears in the direction from the winding start position of the pole piece to the winding end position of the pole piece n Increase successively.

[0016] According to some embodiments of the present invention, on the pole core, a line connecting the starting positions of the plurality of pole tabs is a straight line extending along the radial direction of the pole core.

[0017] According to some embodiments of the present invention, on the pole core, a line connecting the rear end positions of the plurality of pole lugs is a straight line extending along the radial direction of the pole core.

[0018] According to some embodiments of the present invention, the height of the pole lug in the width direction of the pole piece body is the pole lug height, the pole lug height of the pole lug of the n+1th circle is not greater than the pole lug height of the pole lug of the nth circle, and the distance between the pole lug of the n+1th circle and the center of the pole core is greater than the distance between the pole lug of the nth circle and the center of the pole core.

[0019] According to some embodiments of the present invention, the difference between the height of the tab of the n+1th tab and the height of the tab of the nth tab is hc, and hc satisfies: t0≤h c ≤5t0.

[0020] According to some embodiments of the present invention, 1 / 4πD n ≤A n ≤1 / 2πD n , D n is the diameter of the pole core at the nth circle, A n It is the length of the pole lug of the nth circle along the length direction of the pole piece body when the pole piece is in the unfolded state.

[0021] According to the pole core of the embodiment of the second aspect of the present invention, the pole core is wound by a winding unit, the winding trajectory of the winding unit is a spiral line, the winding unit includes a stacked first pole piece, a second pole piece and a diaphragm, the polarities of the first pole piece and the second pole piece are opposite, at least one of the first pole piece and the second pole piece is the pole piece according to the embodiment of the first aspect of the present invention, the diaphragm is arranged between the first pole piece and the second pole piece, the first pole piece includes a first pole piece body and a first pole ear connected to one side of the first pole piece body, the first pole ear constitutes a first pole ear portion, the second pole piece includes a second pole piece body and a second pole ear connected to one side of the second pole piece body, the second pole ear constitutes a second pole ear portion, the first pole ear portion and the second pole ear portion are located at the same end of the pole core in the axial direction of the pole core, and the first pole ear portion and the second pole ear portion are opposite to each other and spaced apart along the radial direction of the pole core.

[0022] According to the battery cell of the embodiment of the present invention, by including the pole piece of the embodiment of the first aspect of the present invention, the battery cell formed by winding the pole piece can make the pole ears with different polarities be located at the same end of the pole core during the winding process, so as to facilitate the separation of the pole ears of the two poles, and the pole ears with different polarities can be separately arranged along the radial direction of the pole core, so that the pole ears of the two poles do not overlap and interfere with each other after being flattened or patted, thereby avoiding internal short circuit of the battery. Since the pole ears with different polarities are located at the same end of the pole core, the pole core can have a higher energy density and it is also convenient to lead out the positive and negative electrodes of the pole core from the same end. There is no need to use the battery cell shell as a conductive component, which can shorten the current flow path, reduce the structural internal resistance, and improve the battery performance.

[0023] According to the pole core of the embodiment of the present invention, the sum of the radians of the first pole lug portion and the radians of the second pole lug portion is in the range of π to 2π.

[0024] A battery cell according to an embodiment of the third aspect of the present invention comprises: a pole core according to an embodiment of the second aspect of the present invention.

[0025] The battery cell according to the embodiment of the present invention includes the pole core according to the embodiment of the second aspect of the present invention. The battery cell has a higher energy density and is also convenient for leading the positive and negative electrodes of the pole core from the same end. There is no need to use the battery cell shell as a conductive component, which can shorten the current flow path, reduce the structural internal resistance, and improve battery performance.

[0026] A battery assembly according to an embodiment of a fourth aspect of the present invention comprises: a battery cell according to an embodiment of the third aspect of the present invention.

[0027] The battery assembly according to the embodiment of the present invention includes a battery cell according to the embodiment of the third aspect of the present invention. The battery cell in the battery cell has a higher energy density and is convenient for leading the positive and negative electrodes of the electrode core from the same end. There is no need to use the battery cell shell as a conductive component, which can shorten the current flow path, reduce the structural internal resistance, and improve battery performance.

[0028] An electrical device according to an embodiment of a fifth aspect of the present invention includes: a battery assembly according to an embodiment of a fourth aspect of the present invention.

[0029] The electrical equipment according to the embodiment of the present invention includes a battery according to the embodiment of the third aspect of the present invention. The pole core of the battery has a high energy density and is convenient for leading the positive and negative poles of the pole core from the same end. There is no need to use the battery cell shell as a conductive component, which can shorten the current flow path, reduce the structural internal resistance, and improve the battery performance.

[0030] According to the design method of the pole piece of the sixth aspect of the present invention, the pole piece is used to be wound to form a pole core, the pole core is wound by a winding unit, the winding trajectory of the pole piece or the pole core is a spiral line, the winding unit includes the stacked pole piece and the diaphragm, the pole piece includes a pole piece body and a pole ear, and the pole ear is connected to one side of the pole piece body in the width direction;

[0031] The pole piece design method comprises: according to the thickness t0 of the winding unit, the diameter D of the pole core at the nth turn n , the pre-winding length L of the diaphragm in the winding unit before the pole piece is wound c and the thickness deviation of the pole piece, determine the starting position of the pole lug of the nth circle.

[0032] According to the design method of the pole piece of the embodiment of the present invention, according to the thickness t0 of the winding unit, the diameter D of the winding unit at the nth turn n and the length A of the nth ring of the pole ear along the length direction of the pole body when the pole piece is unfolded n Determine n During the winding process, the pole ears with different polarities can be located at the same end of the pole core, and the pole ears with different polarities can be separately arranged along the radial direction of the pole core, so that the pole ears of the two poles do not overlap and interfere with each other after being flattened or patted, thereby avoiding internal short circuit of the battery. Since the pole ears with different polarities are located at the same end of the pole core, the pole core can have a higher energy density, and it is also convenient to lead the positive and negative poles of the pole core from the same end. There is no need to use the battery cell shell as a conductive component, which can shorten the current flow path, reduce the structural internal resistance, and improve the battery performance.

[0033] According to some embodiments of the present invention, the starting position of the nth ring of the pole ear is the nth starting position, L xnis the winding length of the pole piece from the winding starting position of the pole piece to the nth starting position, L n -k m *L n ≤L xn ≤L n +k l *L n ,in k m is the deviation coefficient of the starting position of the pole ear of the nth circle when the thickness of the pole piece takes the maximum value within the set deviation range, k l is the deviation coefficient of the starting position of the pole ear of the nth circle when the thickness of the pole piece takes the minimum value within the set deviation range. The formula of the spiral line is: R n =θ*ε n , θ=t0 / 2π.

[0034] According to some embodiments of the present invention, k m =(L n -L nm ) / (π*D n ), k l =(L nl -L n ) / (π*D n ), L nm is the winding length of the pole piece from the winding starting position of the pole piece to the nth starting position when the thickness of the pole piece takes the maximum value within the set deviation range, L nl The winding length of the pole piece from the winding starting position of the pole piece to the nth starting position when the thickness of the pole piece takes a minimum value within the set deviation range.

[0035] According to some embodiments of the present invention, 0≤k m ≤6%, 0≤k l ≤6%.

[0036] According to some embodiments of the present invention, the winding unit includes a stacked positive electrode sheet, a negative electrode sheet and two layers of the separator, and the diameter D of the electrode core at the nth turn is n =D0+t3*4+t2*2+t1*2*n, t0=t1+t2+2t3, D0 is the diameter of the center hole of the pole 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 diaphragm, i3 is the number of pre-winding turns of the diaphragm before the positive electrode sheet is wound, and i2 is the number of pre-winding turns of the negative electrode sheet before the positive electrode sheet is wound.

[0037] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0039] Figure 1 is a three-dimensional schematic diagram of a pole core according to some embodiments of the present invention, wherein a first pole ear and a second pole ear are separately flattened and respectively form a first pole ear portion and a second pole ear portion;

[0040] Figure 2 yes Figure 1 A top view of the middle core;

[0041] Figure 3 yes Figure 1 Cross-section of the middle pole core;

[0042] Figure 4 yes Figure 3 The enlarged view of point B in the middle;

[0043] Figure 5 yes Figure 1 Schematic diagram of the first and second pole ears of the middle pole core when they are not flattened;

[0044] Figure 6 3D schematic diagrams of pole cores according to other embodiments of the present invention, wherein the first pole tab and the second pole tab are flattened separately to form a first pole tab portion and a second pole tab portion respectively;

[0045] Figure 7 yes Figure 6 A top view of the middle core;

[0046] Figure 8 yes Figure 6 Schematic diagram of the first and second pole ears of the middle pole core when not flat;

[0047] Fig. 9 is a schematic diagram of a pole piece in an unfolded state according to some embodiments of the present invention.

[0048] Reference numerals:

[0049] 10. pole core; 11. winding unit; 12. first pole piece; 13. second pole piece; 14. diaphragm; 17. first pole ear portion; 18. second pole ear portion;

[0050] 20. Pole piece; 21. Pole piece body; 22. Pole ear. DETAILED DESCRIPTION

[0051] Embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0052] Reference below Figure 1-Figure 9 A pole piece 20 according to an embodiment of the present invention is described.

[0053] The pole piece 20 according to the first aspect of the present invention is used to wind up the pole core 10, and the winding track of the pole piece 20 is a spiral line. The pole piece 20 includes a pole piece body 21 and a pole ear 22, and the pole ear 22 is connected to one side in the width direction of the pole piece body 21. The winding track of the pole piece 20 refers to the track of the moving point of the pole piece 20 around the rotation axis, that is, the winding needle, gradually away from the winding needle.

[0054] The length direction of the body is set at intervals.

[0055] For example, the spiral may be an Archimedean spiral.

[0056] The starting position of the pole ear 22 located at the nth circle is the nth starting position, L xn is the winding length of the pole piece 20 from the winding starting position of the pole piece 20 to the nth starting position, L n -k m *L n ≤L xn ≤L n +k l *L n ,in k m is the deviation coefficient of the starting position of the pole ear 22 of the nth circle when the thickness of the pole piece 20 takes the maximum value within the set deviation range, k l is the deviation coefficient when the starting position of the pole ear 22 of the nth circle takes the minimum value of the thickness of the pole piece 20 within the set deviation range, 0≤k m ≤6%, 0≤k l ≤6%, the formula of the spiral is: R n =θ*ε n , θ=t0 / 2π, t0 is the thickness of the winding unit 11 wound to form the pole core 10, the winding unit 11 includes the stacked pole pieces 20 and the diaphragm 14, R n is the radius of the pole core 10 at the nth circle, L c is the pre-winding length of the diaphragm 14 in the winding unit 11 before the pole piece 20 is wound. Wherein, θ is the arc parameter, and the rotation arc ε nis the total angle of the pole piece 20 during the winding rotation of the nth circle. By making the pole piece 20 have a winding length L from the winding starting position of the pole piece 20 to the nth starting position xn Meet L n -k m *L n ≤L xn ≤L n +k l *L n ,in After the electrode sheet 20 is wound, the pole tabs 22 of the same pole can be arranged in sequence along the radial direction of the winding unit 11, and the pole tabs 22 of the same pole can be concentrated in a part of the area on one side of the winding unit 11, and sufficient distribution space is reserved for the pole tabs 22 of the other pole, so as to facilitate the separation of the pole tabs 22 of the two poles. When the winding unit 11 includes a positive electrode sheet 20 and a negative electrode sheet 20, the positive pole tabs 22 can be concentrated in a part of the area on one side of the winding unit 11, and the negative pole tabs 22 can be concentrated in another part of the area on the same side of the winding unit 11, so that the areas where the positive pole tabs 22 and the negative pole tabs 22 are arranged do not overlap, and the areas where the positive pole tabs 22 and the negative pole tabs 22 are arranged can be separated, so as to avoid the positive pole tabs 22 and the negative pole tabs 22 from contacting each other and causing a short circuit inside the battery.

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

[0058] According to the pole piece 20 of the embodiment of the present invention, by making the winding length from the winding starting position of the pole piece 20 to the starting position of the pole ear 22 of the nth circle satisfy the above relationship, it is convenient to separate the pole ears 22 of the two poles, and the pole ears 22 of different polarities can be set separately along the radial direction of the pole core, so that the pole ears 22 of the two poles do not overlap and interfere with each other after being flattened or flattened, thereby avoiding internal short circuit of the battery. Since the pole ears 22 of different polarities are located at the same end of the pole core 10, the pole core 10 can have a higher energy density, and it is also convenient to lead the positive and negative poles of the pole core 10 from the same end, without using the battery cell shell as a conductive component, which can shorten the current flow path, reduce the structural internal resistance, and improve the battery performance.

[0059] According to some embodiments of the present invention, the winding unit 11 includes a stacked positive electrode sheet 20, a negative electrode sheet 20 and two layers of separators 14, and the diameter D of the electrode core 10 at the nth turn is n=D0+t3*4+t2*2+t1*2*n, t0=t1+t2+2t3, D0 is the diameter of the central hole of the pole core 10, t1 is the thickness of the positive pole sheet 20, t2 is the thickness of the negative pole sheet 20, t3 is the thickness of the single-layer separator 14, i3 is the number of pre-winding turns of the separator 14 before the positive pole sheet 20 is wound, and i2 is the number of pre-winding turns of the negative pole sheet 20 before the positive pole sheet 20 is wound. Generally, the separator 14 is generally wound more than a circle before the positive pole sheet 20, and the negative pole sheet 20 is wound more than half a circle before the positive pole sheet 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 pole sheet 20. For example, in the process of winding the winding unit to form the electrode core 10, the separator 14 is first wound 1 to 3 times, and then the negative electrode sheet 20 is wound half a circle, and then the separator 14, the negative electrode sheet 20 and the positive electrode sheet 20 are wound together. n is the winding length of the winding unit 11 at the nth starting position, which 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 the present invention, the height of the pole ear 22 in the width direction of the pole piece body 21 is the height of the pole ear 22, and the height of the pole ear 22 of the first circle is h1, and h1 satisfies: 0≤h1≤1 / 2D JR , D JR is the diameter of the pole core 10. By making the height h of the first turn of the pole lug 22 no greater than the diameter D of the winding unit 11 JR , it can be avoided that the height of the pole ear 22 of the first circle is too large, which causes the pole ear 22 to extend outside the winding unit 11 and interfere with the battery cell shell after the pole ear 22 is flattened or patted. By limiting the upper limit value of the height of the pole ear 22 of the first circle, the winding unit 11 can be smoothly assembled into the battery cell shell.

[0061] According to some embodiments of the present invention, the pole piece 20 includes a plurality of pole ears 22, the plurality of pole ears 22 are connected to the same side of the pole piece body 21 in the width direction and are arranged at intervals along the length direction of the pole piece body 21, and the plurality of pole ears 22 of the same polarity are sequentially arranged along the radial direction of the pole core 10. By arranging the plurality of pole ears 22 of the same polarity in the winding unit 11 in sequence along the radial direction of the pole core 10, the pole ears 22 of the same polarity can be concentrated in a part of the area on one side of the pole piece body 21, which is convenient for positioning. Since the multiple pole ears 22 of the pole piece 20 of the same polarity are spaced apart and the winding length from the winding starting position of the pole piece 20 to the starting position of the pole ear 22 of the nth turn satisfies the above relationship, during the winding process, the interval between two adjacent pole ears 22 of the pole piece 20 of the same polarity can reserve sufficient distribution position for the pole ear 22 of the other polarity to facilitate the separation of the pole ears 22 of the two poles. The pole ears 22 of different polarities can be separated along the radial direction of the wound pole core 10, so that the pole ears 22 of the two poles do not overlap and interfere with each other after being flattened or patted, thereby avoiding internal short circuit of the battery.

[0062] According to some embodiments of the present invention, the distance between the pole lug 22 of the n+1th circle and the pole lug 22 of the nth circle when the pole piece 20 is unfolded is d n , the distance between the pole ear 22 of the n+1th circle and the center of the pole core 10 is greater than the distance between the pole ear 22 of the nth circle and the center of the pole core 10, and the distance d between adjacent pole ears 22 in the direction from the winding starting position of the pole piece 20 (refer to the winding starting position g1 in the figure) to the winding ending position of the pole piece 20 (refer to the winding ending position g2 in the figure) n By increasing the distance d between adjacent pole ears 22 in the direction from the winding start position of the pole piece body 21 to the winding end position of the pole piece body 21 n By increasing the size of the electrodes successively, after winding, the electrode tabs 22 of the same pole can be concentrated in a part of the area on one side of the electrode body 21, so as to facilitate the separation of the distribution positions of the positive electrode tabs 22 and the negative electrode tabs 22.

[0063] According to some embodiments of the present invention, on the pole core 10, the line connecting the starting positions of the plurality of pole tabs 22 is a straight line extending along the radial direction of the pole core 10. By making the line connecting the starting positions of the plurality of pole tabs 22 on the pole core 10 a straight line extending along the radial direction of the pole core 10, the pole tabs 22 of the same pole can be concentrated in a part of the area on one side of the pole piece body 21, which is convenient for positioning.

[0064] According to some embodiments of the present invention, on the pole core 10, the line connecting the end positions of the plurality of pole tabs 22 is a straight line extending along the radial direction of the pole core 10. By making the line connecting the end positions of the plurality of pole tabs 22 on the pole core 10 a straight line extending along the radial direction of the pole core 10, it is possible to avoid overlapping of the positions of the pole tabs 22 of different poles.

[0065] According to some embodiments of the present invention, the height of the pole lug 22 in the width direction of the pole piece body 21 is the height of the pole lug 22, the height of the pole lug 22 of the n+1th circle is not greater than the height of the pole lug 22 of the nth circle, and the distance between the pole lug 22 of the n+1th circle and the center of the pole core 10 is greater than the distance between the pole lug 22 of the nth circle and the center of the pole core 10. By making the height of the pole lug 22 of the n+1th circle not greater than the height of the pole lug 22 of the nth circle, it is possible to avoid the pole lug 22 from being too high in height, and after the pole lug 22 is flattened or patted along the diameter from the inside to the outside, the pole lug 22 extends outside the winding unit 11 and interferes with the assembly shell of the pole core 10, so that the pole core 10 can be smoothly assembled with other components.

[0066] According to some embodiments of the present invention, the difference between the height of the tab 22 of the n+1th circle and the height of the tab 22 of the nth circle is hc, and hc satisfies: t0≤h c ≤5t0. After the tabs 22 are flattened or patted, adjacent tabs 22 can have a larger overlap area and a larger current capacity.

[0067] According to some embodiments of the present invention, 1 / 4πD n ≤A n ≤1 / 2πD n , D n is the diameter of the pole core 10 at the nth turn, A n =The length of the n-th turn of the pole ear 22 along the length direction of the pole piece body 21 when the pole piece 20 is unfolded. By making the length of the n-th turn of the pole ear 22 along the length direction of the pole piece body 21 when the pole piece 20 is unfolded not less than / πD n , it can avoid that the length of the pole ear 22 in the winding unit 11 is too short in the circumferential direction, resulting in the pole ear 22 being too small, and the current carrying capacity of the pole ear 22 can be improved; by making the length of the pole ear 22 of the nth circle along the length direction of the pole piece body 21 in the unfolded state of the pole piece 20 not greater than / πD n To avoid overlapping and short-circuiting between the positive electrode tab 22 and the negative electrode tab 22, the tabs 22 on a single pole piece 20 can be concentratedly distributed and sufficient distribution positions can be reserved for the tabs 22 on the pole piece 20 of the other pole, so that the distribution positions of the tabs 22 on the pole pieces 20 of the two poles are separated to ensure the safety of the battery.

[0068] According to the pole core 10 of the embodiment of the second aspect of the present invention, the pole core 10 is wound by a winding unit 11, the winding trajectory of the winding unit 11 is a spiral line, the winding unit 11 includes a stacked first pole piece 12, a second pole piece 13 and a diaphragm 14, the polarities of the first pole piece 12 and the second pole piece 13 are opposite, at least one of the first pole piece 12 and the second pole piece 13 is a pole piece 20 according to the embodiment of the first aspect of the present invention, a diaphragm 14 is provided between the first pole piece 12 and the second pole piece 13, and the first pole piece 12 includes a second pole piece 13. A pole piece body 21 and a first pole ear 22 connected to one side of the first pole piece body 21, the first pole ear 22 constitutes a first pole ear portion 17, the second pole piece 13 includes a second pole piece body 21 and a second pole ear 22 connected to one side of the second pole piece body 21, the second pole ear 22 constitutes a second pole ear portion 18, the first pole ear portion 17 and the second pole ear portion 18 are located at the same end of the pole core 10 in the axial direction of the pole core 10, and the first pole ear portion 17 and the second pole ear portion 18 are opposite to each other and spaced apart along the radial direction of the pole core 10.

[0069] According to the pole core 10 of the embodiment of the present invention, by including the pole piece 20 of the embodiment of the first aspect of the present invention, the pole core 10 formed by winding the pole piece 20 can make the pole ears 22 with different polarities be located at the same end of the pole core 10 during the winding process, so that during the winding process, the pole ears 22 with different polarities can be set separately along the radial direction of the pole core 10, so that the pole ears 22 of the two poles do not overlap and interfere with each other after being flattened or patted, thereby avoiding internal short circuit of the battery. Since the pole ears 22 with different polarities are located at the same end of the pole core 10, the pole core 10 can have a higher energy density while also facilitating the positive and negative electrodes of the pole core 10 to be led out from the same end, without the need to use the pole core 10 shell as a conductive component, which can shorten the current flow path, reduce the structural internal resistance, and improve the battery performance.

[0070] According to the pole core 10 of the embodiment of the present invention, the sum of the radians of the first pole ear portion 17 and the second pole ear portion 18 is in the range of π to 2π. By making the sum of the radians of the first pole ear portion 17 and the second pole ear portion 18 not less than 2π, it is possible to avoid the first pole ear 22 and the second pole ear 22 being too short in the circumferential direction on the winding unit 11, resulting in the pole ear 22 being too small, resulting in poor current carrying capacity and low performance, and the length of the pole ear 22 can be made large enough to improve the performance of the battery; by making the sum of the radians of the first pole ear portion 17 and the second pole ear portion 18 not greater than π, it is possible to avoid the first pole ear portion 17 and the second pole ear portion 18 overlapping in distribution position, and after being flattened or patted, the first pole ear portion 17 and the second pole ear portion 18 overlap and contact to cause a short circuit, which can ensure the safety of the battery.

[0071] A battery cell according to an embodiment of the third aspect of the present invention comprises: a pole core 10 according to an embodiment of the second aspect of the present invention.

[0072] The battery cell according to the embodiment of the present invention includes the pole core 10 according to the embodiment of the second aspect of the present invention. The pole core 10 has a high energy density and is convenient for leading the positive and negative electrodes of the pole core 10 from the same end. There is no need to use the pole core 10 shell as a conductive component, which can shorten the current flow path, reduce the structural internal resistance, and improve the battery performance.

[0073] A battery assembly according to an embodiment of a fourth aspect of the present invention comprises: a battery cell according to an embodiment of the third aspect of the present invention.

[0074] According to the battery assembly of the embodiment of the present invention, by including the battery cell according to the embodiment of the third aspect of the present invention, the pole core 10 in the battery cell has a higher energy density and it is also convenient to lead out the positive and negative electrodes of the pole core 10 from the same end, without using the pole core 10 shell as a conductive component, which can shorten the current flow path, reduce the structural internal resistance, and improve the battery performance.

[0075] An electrical device according to an embodiment of a fifth aspect of the present invention includes: a battery assembly according to an embodiment of a fourth aspect of the present invention.

[0076] According to the electrical equipment of the embodiment of the present invention, by including the battery according to the embodiment of the third aspect of the present invention, the pole core 10 of the battery has a high energy density and it is also convenient to lead out the positive and negative poles of the pole core 10 from the same end, without using the pole core 10 shell as a conductive component, which can shorten the current flow path, reduce the structural internal resistance, and improve the battery performance.

[0077] According to the design method of the pole piece 20 of the embodiment of the sixth aspect of the present invention, the pole piece 20 is used to be wound to form the pole core 10, the pole core 10 is wound by the winding unit 11, the winding track of the pole piece 20 or the pole core 10 is a spiral line, the winding unit 11 includes the stacked pole piece 20 and the diaphragm 14, the pole piece 20 includes a pole piece body 21 and a pole ear 22, and the pole ear 22 is connected to one side of the pole piece body 21 in the width direction;

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

[0079] According to the design method of the pole piece 20 of the embodiment of the present invention, according to the thickness t0 of the winding unit, the diameter D of the winding unit 11 at the nth turn, n and the length A of the pole ear 22 of the nth circle along the length direction of the pole piece body 21 when the pole piece 20 is unfolded.n Determine n During the winding process, the pole lugs 22 with different polarities can be located at the same end of the pole core 10, and the pole lugs 22 with different polarities can be separately arranged along the radial direction of the pole core 10, so that the pole lugs 22 of the two poles do not overlap and interfere with each other after being flattened or patted, thereby avoiding internal short circuit of the battery. Since the pole lugs 22 with different polarities are located at the same end of the pole core 10, the pole core 10 can have a higher energy density, and it is also convenient to lead the positive and negative poles of the pole core 10 from the same end, without using the pole core 10 shell as a conductive component, which can shorten the current flow path, reduce the structural internal resistance, and improve the battery performance.

[0080] According to some embodiments of the present invention, the starting position of the nth circle of the pole lug 22 is the nth starting position, L xn is the winding length of the pole piece 20 from the winding starting position of the pole piece 20 to the nth starting position, L n -k m *L n ≤L xn ≤L n +k l *L n ,in k m is the deviation coefficient of the starting position of the pole ear 22 of the nth circle when the thickness of the pole piece 20 takes the maximum value within the set deviation range, k l is the deviation coefficient of the starting position of the pole ear 22 of the nth circle when the thickness of the pole piece 20 takes the minimum value within the set deviation range. For example, the set deviation range is ±2μm. The formula of the spiral line is: R n =θ*ε n , θ = t0 / 2π. By making the winding length of the winding unit 11 at the nth starting position satisfy L n -k m *L n ≤L xn ≤L n +k l *L n ,in After the electrode sheet 20 is wound, the pole tabs 22 of the same pole are arranged in sequence along the radial direction of the winding unit 11, and the pole tabs 22 of the same pole can be concentrated in a part of the area on one side of the winding unit 11, and sufficient distribution space is reserved for the pole tabs 22 of the other pole, so as to facilitate the separation of the pole tabs 22 of the two poles. When the winding unit 11 includes a positive electrode sheet 20 and a negative electrode sheet 20, the positive pole tabs 22 can be concentrated in a part of the area on one side of the winding unit 11, and the negative pole tabs 22 can be concentrated in another part of the area on the same side of the winding unit 11, so that the areas where the positive pole tabs 22 and the negative pole tabs 22 are arranged do not overlap, and the areas where the positive pole tabs 22 and the negative pole tabs 22 are arranged can be separated, so as to avoid the positive pole tabs 22 and the negative pole tabs 22 from contacting each other and causing a short circuit inside the battery. Through this design, the starting position of the nth turn of the pole ear 22 can be calculated, so that during the winding process of the pole piece 20, the starting position of the nth turn of the pole ear 22 can be located at a pre-designed position, ensuring the winding molding quality of the pole piece 20 in the subsequent winding process.

[0081] By making the winding length of the winding unit 11 at the nth starting position satisfy L n -k m *L n ≤L xn ≤L n +k l *L n , which can reduce the influence of the thickness fluctuation of the positive electrode sheet 20 or the thickness fluctuation of the negative electrode sheet 20 in the incoming material 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 the present invention, k m =(L n -L nm ) / (π*D n ), k l =(L nl -L n ) / (π*D n ), L nm is the winding length of the pole piece 20 from the winding starting position of the pole piece 20 to the nth starting position when the thickness of the pole piece 20 takes the maximum value within the set deviation range, L nl L is the winding length of the pole piece 20 from the winding starting position of the pole piece 20 to the nth starting position when the thickness of the pole piece 20 takes the minimum value within the set deviation range. nm L can be calculated from the above n The formula is calculated to calculate L nm In the formula, t0 is the thickness of the winding unit 11 when the thickness of the pole piece 20 takes the maximum value within the set deviation range; L nl L can be calculated from the above nThe formula is calculated to calculate L nl In the formula, t0 is the thickness of the winding unit 11 when the thickness of the pole piece 20 takes the minimum value within the set deviation range.

[0083] According to some embodiments of the present invention, 0≤k m ≤6%, 0≤k l According to the different thickness specifications and different incoming pole pieces 20 used in the actual production process, it can be calculated that the deviation coefficient of the starting position of the nth turn of pole lugs 22 is basically less than 6%, so that the above formula can be basically applicable to the pole pieces 20 used in the production process.

[0084] According to some embodiments of the present invention, the winding unit 11 includes a stacked positive electrode sheet 20, a negative electrode sheet 20 and two layers of separators 14, and the diameter F of the electrode core 10 at the nth turn is n =D0+t3*4+t2*2+t1*2*n, t0=t1+t2+2t3, D0 is the diameter of the center hole of the pole core 10, t1 is the thickness of the positive electrode plate 20, t2 is the thickness of the negative electrode plate 20, t3 is the thickness of the single-layer diaphragm 14, i3 is the number of pre-winding turns of the diaphragm 14 before the positive electrode plate 20 is wound, and i2 is the number of pre-winding turns of the negative electrode plate 20 before the positive electrode plate 20 is wound.

[0085] Among them, in actual production, before the winding unit 11 is wound, the diameter of the center hole of the pole core 10 cannot be measured. Since the winding unit 11 is wound on a winding needle, the diameter of the winding needle is basically consistent with 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 the actual production process, the thickness of the positive electrode sheet 20, the thickness of the negative electrode sheet 20, the thickness of the diaphragm 14 and the diameter of the winding needle are all known. According to the thickness of the positive electrode sheet 20, the thickness of the negative electrode sheet 20, the thickness of the diaphragm 14 and the diameter of the winding needle, the thickness t0 of the winding unit 11 can be easily obtained.

Claims

1. A pole piece, characterized in that: Used for winding to form a pole core, the winding track of the pole piece is a spiral line, the pole piece includes a pole piece body and a pole ear, and the pole ear is connected to one side of the pole piece body in the width direction; The starting position of the pole ear located at the nth circle is the nth starting position, L xn is the winding length of the pole piece from the winding starting position of the pole piece to the nth starting position, L n -k m *L n ≤L xn ≤L n +k l *L n ,in k m is the deviation coefficient of the starting position of the pole ear of the nth circle when the thickness of the pole piece takes the maximum value within the set deviation range, k l is the deviation coefficient of the starting position of the pole ear of the nth circle when the thickness of the pole piece takes the minimum value within the set deviation range, 0≤k m ≤6%, 0≤k l ≤6%, the formula of the spiral is: R n =θ*ε n , θ=t0 / 2π, t0 is the thickness of the winding unit wound to form the pole core, the winding unit includes the stacked pole pieces and diaphragms, R n is the radius of the pole core at the nth circle, L c It is the pre-winding length of the diaphragm in the winding unit before the pole piece is wound.

2. The pole piece according to claim 1, characterized in that: The winding unit includes a stacked positive electrode sheet, a negative electrode sheet and two layers of the separator, and the diameter D of the pole core at the nth turn is n =D0+t3*4+t2*2+t1*2*n, t0=t1+t2+2t3, D0 is the diameter of the center hole of the pole 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 diaphragm, i3 is the number of pre-winding turns of the diaphragm before the positive electrode sheet is wound, and i2 is the number of pre-winding turns of the negative electrode sheet before the positive electrode sheet is wound.

3. The pole piece according to claim 1, characterized in that: The height of the pole ear in the width direction of the pole piece body is the pole ear height, and the height of the pole ear of the first circle is h1, and h1 satisfies: 0≤h1≤1 / 2D JR , D JR is the diameter of the pole core.

4. The pole piece according to claim 1, characterized in that: The pole piece includes a plurality of pole ears, which are connected to the same side of the pole piece body in the width direction and are arranged at intervals along the length direction of the pole piece body. The plurality of pole ears of the same polarity are arranged in sequence along the radial direction of the pole core.

5. The pole piece according to claim 4, characterized in that: The distance between the pole ear of the n+1th circle and the pole ear of the nth circle when the pole piece is unfolded is d n , the distance between the pole ear of the n+1th circle and the center of the pole core is greater than the distance between the pole ear of the nth circle and the center of the pole core, and the spacing d between adjacent pole ears in the direction from the winding start position of the pole piece to the winding end position of the pole piece n Increase successively.

6. The pole piece according to claim 4, characterized in that: On the pole core, a line connecting the starting positions of the plurality of pole tabs is a straight line extending along the radial direction of the pole core.

7. The pole piece according to claim 6, characterized in that: On the pole core, a line connecting the rear end positions of the plurality of pole lugs is a straight line extending along the radial direction of the pole core.

8. The pole piece according to claim 1, characterized in that: The height of the pole lug in the width direction of the pole piece body is the pole lug height, the pole lug height of the pole lug of the n+1th circle is not greater than the pole lug height of the pole lug of the nth circle, and the distance between the pole lug of the n+1th circle and the center of the pole core is greater than the distance between the pole lug of the nth circle and the center of the pole core.

9. The pole piece according to claim 8, characterized in that: The difference between the height of the tab of the n+1th tab and the height of the tab of the nth tab is hc, and hc satisfies: t0≤h c ≤5t0.

10. The pole piece according to claim 1, characterized in that: 1 / 4πD n ≤A n ≤1 / 2πD n , D n is the diameter of the pole core at the nth circle, A n It is the length of the pole lug of the nth circle along the length direction of the pole piece body when the pole piece is in the unfolded state.

11. A pole core, characterized in that: The pole core is wound by a winding unit, the winding track of the winding unit is a spiral line, the winding unit includes a stacked first pole piece, a second pole piece and a diaphragm, the first pole piece and the second pole piece have opposite polarities, and at least one of the first pole piece and the second pole piece is According to the pole piece described in any one of claims 1-10, the diaphragm is provided between the first pole piece and the second pole piece, the first pole piece comprises a first pole piece body and a first pole ear connected to one side of the first pole piece body, the first pole ear constitutes a first pole ear portion, the second pole piece comprises a second pole piece body and a second pole ear connected to one side of the second pole piece body, the second pole ear constitutes a second pole ear portion, the first pole ear portion and the second pole ear portion are located at the same end of the pole core in the axial direction of the pole core, and the first pole ear portion and the second pole ear portion are opposite to each other and spaced apart in the radial direction of the pole core.

12. The pole core according to claim 11, characterized in that: The sum of the radians of the first pole lug portion and the radians of the second pole lug portion is in a range of π to 2π.

13. A battery cell, characterized in that: include: A pole core according to claim 11 or 12.

14. A battery assembly, characterized in that: include: The battery cell according to claim 13.

15. An electrical equipment, characterized in that: include: A battery assembly according to claim 14.

16. A method for designing a pole piece, characterized in that: The pole piece is used to be wound to form a pole core, the pole core is wound by a winding unit, the winding track of the pole piece or the pole core is a spiral line, the winding unit includes the stacked pole piece and the diaphragm, the pole piece includes a pole piece body and a pole ear, and the pole ear is connected to one side of the pole piece body in the width direction; The pole piece design method comprises: according to the thickness t0 of the winding unit, the diameter D of the pole core at the nth turn n , the pre-winding length L of the diaphragm in the winding unit before the pole piece is wound c and the thickness deviation of the pole piece, determine the starting position of the pole lug of the nth circle.

17. The pole piece design method according to claim 16, characterized in that: The starting position of the nth ring of lugs is the nth starting position, L xn is the winding length of the pole piece from the winding starting position of the pole piece to the nth starting position, L n -k m *L n ≤L xn ≤L n +k l *L n ,in k m is the deviation coefficient of the starting position of the pole ear of the nth circle when the thickness of the pole piece takes the maximum value within the set deviation range, k l is the deviation coefficient of the starting position of the pole ear of the nth circle when the thickness of the pole piece takes the minimum value within the set deviation range. The formula of the spiral line is: R n =θ*ε n , θ=t0 / 2π.

18. The pole piece design method according to claim 17, characterized in that: k m =(L n -L nm ) / (π*D n ), k l =(L nl -L n ) / (π*D n ), L nm is the winding length of the pole piece from the winding starting position of the pole piece to the nth starting position when the thickness of the pole piece takes the maximum value within the set deviation range, L nl The winding length of the pole piece from the winding starting position of the pole piece to the nth starting position when the thickness of the pole piece takes a minimum value within the set deviation range.

19. The pole piece design method according to claim 17, characterized in that: 0≤k m ≤6%,0≤k l ≤6%。 20. The pole piece design method according to claim 17, characterized in that: The winding unit includes a stacked positive electrode sheet, a negative electrode sheet and two layers of the separator, and the diameter D of the pole core at the nth turn is n =D0+t3*4+t2*2+k1*2*n, t0=t1+t2+2t3, D0 is the diameter of the center hole of the pole 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 diaphragm, i3 is the number of pre-winding turns of the diaphragm before the positive electrode sheet is wound, and i2 is the number of pre-winding turns of the negative electrode sheet before the positive electrode sheet is wound.

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