Battery cell parameter determination method and system, electronic equipment, storage medium and battery cell

Abstract

The invention provides a parameter determination method and system of a battery cell, electronic equipment, a storage medium and the battery cell. The method comprises the following steps: acquiring a relationship between the length and the surface density of the nth group of pole pieces of the battery cell to be designed; determining the relationship between the surface density of the C surface of the (n + 1) th layer of negative pole piece and the surface density of the D surface of the nth layer of negative pole piece and the relationship between the surface density of the C surface of the (n + 1) th layer of negative pole piece and the surface density of the D surface of the (n + 1) th layer of negative pole piece according to the relationship between the length and the surface density of the nth group of pole pieces under the condition that the capacity ratios of the positive pole and the negative pole corresponding to each group of pole pieces are equal; and determining the surface density of the C surface of the (n + 1) th layer of negative pole piece, the surface density of the D surface of the nth layer of negative pole piece and the surface density of the D surface of the (n + 1) th layer of negative pole piece according to the relationship between the surface densities. According to the invention, the parameters of the battery cell can be rapidly determined, and the capacity ratios of the positive electrode and the negative electrode corresponding to each group of pole pieces of the battery cell designed according to the parameters can be ensured to be equal, so that the cycle performance and the energy density of the battery cell can be improved.

Description

Technical Field

[0001] This application relates to the technical field of battery cells, and particularly to a method and system for determining parameters of a battery cell, an electronic device, a storage medium, and a battery cell. Background Art

[0002] Existing battery cell structures are diverse, but most structures use a winding needle as the central axis, and the positive electrode sheet, negative electrode sheet, and separator are wound around the winding needle. In this winding structure, the positive and negative electrode sheets are in an arc shape, and the lengths of the positive and negative electrode sheets increase with the increase in the number of winding layers.

[0003] The areal density of each surface of the positive and negative electrode sheets is a key parameter for designing a battery cell. Currently, most designs are made by setting the same areal density for each surface of the positive electrode sheets in the same layer, setting the same areal density for the same surface of different layers of positive electrode sheets, and setting the same areal density for the same surface of each layer of negative electrode sheets.

[0004] Since the lengths of the positive and negative electrode sheets increase with the increase in the number of winding layers, when the areal density of the same surface of each layer of negative electrode sheets is equal, the capacity ratios of adjacent positive and negative electrode sheets in each group of the designed battery cell cannot all be kept consistent, resulting in poor cycle performance and energy density of the battery cell. Summary of the Invention

[0005] The main objective of the embodiments of this application is to propose a method and system for determining parameters of a battery cell, an electronic device, a storage medium, and a battery cell, aiming to determine the battery cell parameters that make the positive and negative capacity ratios corresponding to each group of electrode sheets of the battery cell equal, thereby improving the cycle performance and energy density of the battery cell.

[0006] The present application provides a method for determining parameters of an electric core. The electric core to be designed includes a winding needle, multiple layers of positive electrode plates, and multiple layers of negative electrode plates. The winding needle is used to wind the multiple layers of positive electrode plates and the multiple layers of negative electrode plates; each layer of positive electrode plate includes an A side facing away from the winding needle and a B side facing the winding needle; each layer of negative electrode plate includes a C side facing the winding needle and a D side facing away from the winding needle; the method for determining parameters includes: obtaining the relationship between the length and the areal density of the nth group of electrode plates of the electric core to be designed; the relationship between the length and the areal density of the nth group of electrode plates includes the relationship between the length of the A side of the nth layer of positive electrode plate and the areal density of the A side, the relationship between the length of the B side of the nth layer of positive electrode plate and the areal density of the B side, the relationship between the length of the C side of the (n + 1)th layer of negative electrode plate and the areal density of the C side, and the relationship between the length of the D side of the nth layer of negative electrode plate and the areal density of the D side; the nth layer of positive electrode plate is located between the nth layer of negative electrode plate and the (n + 1)th layer of negative electrode plate; n is a positive integer; under the condition that the positive and negative capacity ratios corresponding to each group of electrode plates are equal, according to the relationship between the length and the areal density of the nth group of electrode plates, the areal density of the A side and the areal density of the B side of the nth layer of positive electrode plate, and the areal density of the B side of the (n + 1)th layer of positive electrode plate, determine the relationship between the areal density of the C side of the (n + 1)th layer of negative electrode plate and the areal density of the D side of the nth layer of negative electrode plate, and the relationship between the areal density of the C side of the (n + 1)th layer of negative electrode plate and the areal density of the D side of the (n + 1)th layer of negative electrode plate; according to the relationship between the areal density of the C side of the (n + 1)th layer of negative electrode plate and the areal density of the D side of the nth layer of negative electrode plate, and the relationship between the areal density of the C side of the (n + 1)th layer of negative electrode plate and the areal density of the D side of the (n + 1)th layer of negative electrode plate, determine the areal density of the C side of the (n + 1)th layer of negative electrode plate, the areal density of the D side of the nth layer of negative electrode plate, and the areal density of the D side of the (n + 1)th layer of negative electrode plate.

[0007] In one embodiment, the cell to be designed further includes multiple layers of separator; the winding pin is further configured to wind the multiple layers of separator; the obtaining of the relationship between the lengths and areal densities of multiple sets of electrode sheets of the cell to be designed includes: obtaining a first target electrode sheet surface located between the winding pin and the target point on the A surface of the nth layer of positive electrode sheet; the target point on the A surface of the nth layer of positive electrode sheet includes the starting point of the A surface of the nth layer of positive electrode sheet and the ending point of the A surface of the nth layer of positive electrode sheet; according to the radius of the winding pin, the thicknesses of each layer of separator located between the winding pin and the target point on the A surface of the nth layer of positive electrode sheet, and the relationship between the thickness and the areal density of the first target electrode sheet surface, determining the first distance information between the A surface of the nth layer of positive electrode sheet and the winding pin; the first distance information includes the first distance between the starting point of the A surface of the nth layer of positive electrode sheet and the center point of the winding pin, and the second distance between the ending point of the A surface of the nth layer of positive electrode sheet and the center point; according to the first distance, the first difference value, and the first angle range corresponding to the A surface of the nth layer of positive electrode sheet, determining the relationship between the length and the areal density of the A surface of the nth layer of positive electrode sheet; the first difference value is the difference value of the second distance relative to the first distance; the first angle range is the range of the included angle formed by taking the center point of the winding pin as the vertex, any point on the A surface of the nth layer of positive electrode sheet, the center point of the winding pin, and the starting point of the A surface of the nth layer of positive electrode sheet.

[0008] In one embodiment, after determining the areal density of the C surface of the (n + 1)th layer of negative electrode sheet, the areal density of the D surface of the nth layer of negative electrode sheet, and the areal density of the D surface of the (n + 1)th layer of negative electrode sheet, the parameter determination method further includes: determining the length of the C surface of the (n + 1)th layer of negative electrode sheet according to the areal density of the C surface of the (n + 1)th layer of negative electrode sheet and the relationship between the length and the areal density of the C surface of the (n + 1)th layer of negative electrode sheet; determining the length of the D surface of the nth layer of negative electrode sheet according to the areal density of the D surface of the nth layer of negative electrode sheet and the relationship between the length and the areal density of the D surface of the nth layer of negative electrode sheet.

[0009] In one embodiment, determining the C-side areal density of the (n + 1)-th layer negative electrode tab, the D-side areal density of the n-th layer negative electrode tab, and the D-side areal density of the (n + 1)-th layer negative electrode tab according to the relationship between the C-side areal density of the (n + 1)-th layer negative electrode tab and the D-side areal density of the n-th layer negative electrode tab, and the relationship between the C-side areal density of the (n + 1)-th layer negative electrode tab and the D-side areal density of the (n + 1)-th layer negative electrode tab includes: determining the C-side areal density of the (n + 1)-th layer negative electrode tab, the D-side areal density of the n-th layer negative electrode tab, and the D-side areal density of the (n + 1)-th layer negative electrode tab according to the relationship between the C-side areal density of the (n + 1)-th layer negative electrode tab and the D-side areal density of the n-th layer negative electrode tab, the relationship between the C-side areal density of the (n + 1)-th layer negative electrode tab and the D-side areal density of the (n + 1)-th layer negative electrode tab, and a first preset relationship and / or a second preset relationship; wherein, the first preset relationship is a preset relationship between the C-side areal density and the D-side areal density of the negative electrode tab of the same layer; the second preset relationship is a preset relationship between the areal densities of the same side of the negative electrode tabs of different layers; the first preset relationship and the second preset relationship are set based on the positive-negative capacity ratio.

[0010] In one embodiment, the first preset relationship is that the proportion range of the C-side areal density of each layer of negative electrode tab is [45%, 50%); the second preset relationship is that the areal densities of the same side of the negative electrode tabs of different layers are not equal, and the deviation of the C-side areal densities of two adjacent layers of negative electrode tabs is less than or equal to 2%.

[0011] In one embodiment, after obtaining the relationship between the length and the areal density of the n-th set of tabs of the battery cell to be designed, the parameter determination method further includes: setting the positive-negative capacity ratio to a target capacity ratio; determining the C-side areal density of the (n + 1)-th layer negative electrode tab according to the target capacity ratio, the relationship between the A-side length and the A-side areal density of the n-th layer positive electrode tab, the relationship between the C-side length and the C-side areal density of the (n + 1)-th layer negative electrode tab, and the A-side areal density of the n-th layer positive electrode tab; determining the D-side areal density of the n-th layer negative electrode tab according to the target capacity ratio, the relationship between the B-side length and the B-side areal density of the n-th layer positive electrode tab, the relationship between the D-side length and the D-side areal density of the n-th layer negative electrode tab, and the B-side areal density of the n-th layer positive electrode tab.

[0012] The present application also provides a parameter determination system for an electric core. The to-be-designed electric core includes a winding pin, multiple layers of positive electrode plates, and multiple layers of negative electrode plates; the winding pin is used to wind the multiple layers of positive electrode plates and the multiple layers of negative electrode plates; each layer of positive electrode plate includes an A side facing away from the winding pin and a B side facing the winding pin; each layer of negative electrode plate includes a C side facing the winding pin and a D side facing away from the winding pin; the parameter determination system includes: an acquisition module, a first determination module, and a second determination module; the acquisition module is used to acquire the relationship between the length and areal density of the nth group of electrode plates of the to-be-designed electric core; the relationship between the length and areal density of the nth group of electrode plates includes the relationship between the length of the A side of the nth layer of positive electrode plate and the areal density of the A side, the relationship between the length of the B side of the nth layer of positive electrode plate and the areal density of the B side, the relationship between the length of the C side of the (n + 1)th layer of negative electrode plate and the areal density of the C side, and the relationship between the length of the D side of the nth layer of negative electrode plate and the areal density of the D side; the nth layer of positive electrode plate is located between the nth layer of negative electrode plate and the (n + 1)th layer of negative electrode plate; n is a positive integer; the first determination module is used to, under the condition that the positive and negative capacity ratios corresponding to each group of electrode plates are equal, determine the relationship between the areal density of the C side of the (n + 1)th layer of negative electrode plate and the areal density of the D side of the nth layer of negative electrode plate, and the relationship between the areal density of the C side and the areal density of the D side of the (n + 1)th layer of negative electrode plate according to the relationship between the length and areal density of the nth group of electrode plates, the areal density of the A side and the areal density of the B side of the nth layer of positive electrode plate, and the areal density of the B side of the (n + 1)th layer of positive electrode plate; the second determination module is used to determine the areal density of the C side of the (n + 1)th layer of negative electrode plate, the areal density of the D side of the nth layer of negative electrode plate, and the areal density of the D side of the (n + 1)th layer of negative electrode plate according to the relationship between the areal density of the C side of the (n + 1)th layer of negative electrode plate and the areal density of the D side of the nth layer of negative electrode plate, and the relationship between the areal density of the C side and the areal density of the D side of the (n + 1)th layer of negative electrode plate.

[0013] The present application also provides an electronic device, which includes a memory and a processor. The memory stores a computer program, and when the processor executes the computer program, the above parameter determination method is implemented.

[0014] The present application also provides a computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor, the above parameter determination method is implemented.

[0015] The present application also provides an electric core, and the electric core includes the parameters determined by the above parameter determination method.

[0016] A method, system, electronic device, storage medium and battery cell for determining parameters of a battery cell provided by the present application can quickly determine the parameters of the battery cell based on the relationship between the C-side surface density of the (n + 1)-th negative electrode tab and the D-side surface density of the n-th negative electrode tab, and the relationship between the C-side surface density of the (n + 1)-th negative electrode tab and the D-side surface density of the (n + 1)-th negative electrode tab, under the condition that the positive and negative capacity ratios corresponding to each group of tabs are equal. Moreover, it can ensure that for the battery cell designed according to these parameters, the positive and negative capacity ratios corresponding to each group of tabs are equal, thereby improving the cycle performance and energy density of the battery cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a schematic flowchart of the method for determining parameters of a battery cell provided by an embodiment of the present application;

[0018] Figure 2 is a schematic diagram of the tabs of the battery cell provided by an embodiment of the present application Figure 1 ;

[0019] Figure 3 is a schematic diagram of the tabs of the battery cell provided by an embodiment of the present application Figure 2 ;

[0020] Figure 4a is a schematic diagram of the tab length ratio of the battery cells in the solution group provided by an embodiment of the present application;

[0021] Figure 4b is a schematic diagram of the tab surface density of the battery cells in the solution group provided by an embodiment of the present application;

[0022] Figure 4c is a schematic diagram of the positive and negative capacity ratio of the battery cells in the solution group provided by an embodiment of the present application;

[0023] Figure 5a is a schematic diagram of the positive and negative capacity ratio of the control group battery cells provided by an embodiment of the present application Figure 1 ;

[0024] Figure 5b is a schematic diagram of the positive and negative capacity ratio of the control group battery cells provided by an embodiment of the present application Figure 2 ;

[0025] Figure 6 is a schematic structural diagram of the system for determining parameters of a battery cell provided by an embodiment of the present application;

[0026] Figure 7 is a schematic structural diagram of an embodiment of the electronic device provided by an embodiment of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] The technical solutions in the embodiments of the present application will be clearly described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are some, but not all, of the embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application belong to the scope of protection of the present application.

[0028] The terms "first", "second", etc. in the description and claims of the present application are used to distinguish similar objects, rather than to describe a specific order or sequence. It should be understood that such data may be interchanged under appropriate circumstances so that the embodiments of the present application can be implemented in an order different from those illustrated or described herein, and the objects distinguished by "first", "second", etc. are generally of the same category, and the number of objects is not limited. For example, the first object may be one or more. In addition, "and / or" in the description and claims means at least one of the connected objects, and the character " / " generally indicates an "or" relationship between the associated objects before and after.

[0029] The method for determining the parameters of the battery cell provided by the embodiments of the present application can be applied to an electronic device, and further, can also be applied to the software of the electronic device; wherein, the electronic device can be a terminal or a server. In some embodiments, the terminal can be a laptop computer, a desktop computer, etc.; the server can be configured as an independent physical server, or can be configured as a server cluster or a distributed system composed of multiple physical servers; the software can be an application for implementing the method for determining the parameters of the battery cell, etc., but is not limited to the above forms.

[0030] The method for determining the parameters of the battery cell provided by the embodiments of the present application will be described in detail below with reference to the accompanying drawings through specific embodiments.

[0031] A method for determining the parameters of a battery cell provided by an embodiment of the present application. The battery cell to be designed includes a winding pin, multiple layers of positive electrode sheets, and multiple layers of negative electrode sheets. The winding pin is used to wind the multiple layers of positive electrode sheets and the multiple layers of negative electrode sheets; each layer of positive electrode sheet includes an A side facing away from the winding pin and a B side facing the winding pin; each layer of negative electrode sheet includes a C side facing the winding pin and a D side facing away from the winding pin. Please refer to Figure 1 , a method for determining the parameters of a battery cell provided by an embodiment of the present application may include:

[0032] Step S101: Obtain the relationship between the length and the areal density of the nth group of electrode sheets of the battery cell to be designed; the relationship between the length and the areal density of the nth group of electrode sheets includes the relationship between the length of the A side of the nth layer of positive electrode sheets and the areal density of the A side, the relationship between the length of the B side of the nth layer of positive electrode sheets and the areal density of the B side, the relationship between the length of the C side of the (n + 1)th layer of negative electrode sheets and the areal density of the C side, and the relationship between the length of the D side of the nth layer of negative electrode sheets and the areal density of the D side; the nth layer of positive electrode sheets is located between the nth layer of negative electrode sheets and the (n + 1)th layer of negative electrode sheets; n is a positive integer;

[0033] Step S102: Under the condition that the positive and negative electrode capacity ratios corresponding to each group of electrode sheets are equal, according to the relationship between the length and the areal density of the nth group of electrode sheets, the areal density of the A side and the areal density of the B side of the nth layer of positive electrode sheets, and the areal density of the B side of the (n + 1)th layer of positive electrode sheets, determine the relationship between the areal density of the C side of the (n + 1)th layer of negative electrode sheets and the areal density of the D side of the nth layer of negative electrode sheets, and the relationship between the areal density of the C side and the areal density of the D side of the (n + 1)th layer of negative electrode sheets;

[0034] Step S103: According to the relationship between the areal density of the C side of the (n + 1)th layer of negative electrode sheets and the areal density of the D side of the nth layer of negative electrode sheets, and the relationship between the areal density of the C side and the areal density of the D side of the (n + 1)th layer of negative electrode sheets, determine the areal density of the C side of the (n + 1)th layer of negative electrode sheets, the areal density of the D side of the nth layer of negative electrode sheets, and the areal density of the D side of the (n + 1)th layer of negative electrode sheets.

[0035] Based on the relationship between the areal density of the C side of the (n + 1)th layer of negative electrode sheets and the areal density of the D side of the nth layer of negative electrode sheets, and the relationship between the areal density of the C side and the areal density of the D side of the (n + 1)th layer of negative electrode sheets determined under the condition that the positive and negative electrode capacity ratios corresponding to each group of electrode sheets are equal, the embodiments of the present application can quickly determine the parameters of the battery cell, and can ensure that for the battery cell designed according to the parameters, the positive and negative electrode capacity ratios corresponding to each group of electrode sheets are equal, thereby improving the cycle performance and energy density of the battery cell.

[0036] Such as Figure 2As shown, each layer of the positive electrode plate includes a positive electrode current collector r and coating areas on both sides of the positive electrode current collector r. Optionally, for each layer of the positive electrode plate, the coating area of the positive electrode current collector r facing away from the winding needle is defined as the A side of the positive electrode plate, which is a convex surface, and the coating area of the positive electrode current collector r facing the winding needle is defined as the B side of the positive electrode plate, which is a concave surface. Similarly, each layer of the negative electrode plate includes a negative electrode current collector s and coating areas on both sides of the negative electrode current collector. Optionally, for each layer of the negative electrode plate, the coating area of the negative electrode current collector s facing away from the winding needle is defined as the D side of the negative electrode plate, which is a convex surface, and the coating area of the negative electrode current collector s facing the winding needle is defined as the C side of the negative electrode plate, which is a concave surface. Optionally, the A side of the nth layer of the positive electrode plate, the B side of the nth layer of the positive electrode plate, the D side of the nth layer of the negative electrode plate, and the C side of the (n + 1)th layer of the negative electrode plate are determined as the nth group of electrode plates. The A side of the nth layer of the positive electrode plate faces the C side of the (n + 1)th layer of the negative electrode plate, and the B side of the nth layer of the positive electrode plate faces the D side of the nth layer of the negative electrode plate.

[0037] As Figure 3 shown, the negative electrode plates can be divided into multiple layers of negative electrode plates, and the positive electrode plates can be divided into multiple layers of positive electrode plates according to the number of turns of the winding needle when the negative electrode plates and the positive electrode plates are wound synchronously around the winding needle. Further, the intersection point of the transverse line L in the width direction of the starting position of the negative electrode plate wound synchronously with the positive electrode plate around the winding needle and the center line of the negative electrode current collector s of the first layer of the negative electrode plate can be defined as the starting point C of the C side of the first layer of the negative electrode plate 10 , and the position on the center line of the negative electrode current collector s of the first layer of the negative electrode plate that reaches after rotating 360 degrees around the center point of the winding needle in the winding direction of the first layer of the negative electrode plate starting from the starting point C of the C side of the first layer of the negative electrode plate 10 can be defined as the ending point C of the C side of the first layer of the negative electrode plate; then, the ending point C of the C side of the first layer of the negative electrode plate 11 can be defined as the starting point C of the C side of the second layer of the negative electrode plate 11 , and the position on the center line of the negative electrode current collector s of the second layer of the negative electrode plate that reaches after rotating 360 degrees around the center point of the winding needle in the winding direction of the second layer of the negative electrode plate starting from the starting point C of the C side of the second layer of the negative electrode plate 20 can be defined as the ending point C of the C side of the second layer of the negative electrode plate 20 . According to the same rule, the starting point C of the C side of the nth layer of the negative electrode plate 21 , and the ending point C of the C side of the nth layer of the negative electrode plate n0 can be obtained n1 .

[0038] Similarly, the intersection point of the cross-section line L' in the width direction of the positive electrode tab and the center line r of the positive electrode current collector of the first layer of the positive electrode tab with the winding needle synchronously can be defined as the starting point B of the B side of the first layer of the positive electrode tab 10 , optionally, the cross-section line L and the cross-section line L' are on the same straight line; then, starting from the starting point B of the B side of the first layer of the positive electrode tab 10 , rotating 360 degrees around the center point of the winding needle along the center line r of the positive electrode current collector of the first layer of the positive electrode tab in the winding direction of the first layer of the positive electrode tab, the position on the center line r of the positive electrode current collector of the first layer of the positive electrode tab reached can be defined as the ending point B of the B side of the first layer of the positive electrode tab 11 ; then, the ending point B of the B side of the first layer of the positive electrode tab 11 can be defined as the starting point B of the B side of the second layer of the positive electrode tab 20 , starting from the starting point B of the B side of the second layer of the positive electrode tab 20 , rotating 360 degrees around the center point of the winding needle along the center line r of the positive electrode current collector of the second layer of the positive electrode tab in the winding direction of the second layer of the positive electrode tab, the position on the center line r of the positive electrode current collector of the second layer of the positive electrode tab reached can be defined as the ending point B of the B side of the second layer of the positive electrode tab 21 , according to the same rule, the starting point B of the B side of the nth layer of the positive electrode tab n0 and the ending point B of the B side of the nth layer of the positive electrode tab n1 can be obtained.

[0039] Further, the intersection point of the cross-section line L and the edge line of the D side of the first layer of the negative electrode tab away from the winding needle can be defined as the starting point D of the D side of the first layer of the negative electrode tab 10 , starting from the starting point D of the D side of the first layer of the negative electrode tab 10 , rotating 360 degrees around the center point of the winding needle along the edge line of the D side of the first layer of the negative electrode tab away from the winding needle in the winding direction of the first layer of the negative electrode tab, the position on the edge line of the D side of the first layer of the negative electrode tab away from the winding needle reached can be defined as the ending point D of the D side of the first layer of the negative electrode tab 11 ; then, the ending point D of the D side of the first layer of the negative electrode tab 11 can be defined as the starting point D of the D side of the second layer of the negative electrode tab 20 , starting from the starting point D of the D side of the second layer of the negative electrode tab 20 , rotating 360 degrees around the center point of the winding needle along the edge line of the D side of the second layer of the negative electrode tab away from the winding needle in the winding direction of the second layer of the negative electrode tab, the position on the edge line of the D side of the second layer of the negative electrode tab away from the winding needle reached can be defined as the ending point D of the D side of the second layer of the negative electrode tab 21 , according to the same rule, the starting point D of the D side of the nth layer of the negative electrode tab n0 and the ending point D of the D side of the nth layer of the negative electrode tab can be obtainedn1 。

[0040] Similarly, the intersection point of the transverse line L' and the edge line of the A side of the first-layer positive electrode tab away from the winding needle can be defined as the starting point A of the A side of the first-layer positive electrode tab. 10 The starting point A of the A side of the first-layer positive electrode tab can be used 10 to rotate 360 degrees around the center point of the winding needle in the winding direction of the first-layer positive electrode tab along the edge line of the A side of the first-layer positive electrode tab away from the winding needle. The position on the edge line of the A side of the first-layer positive electrode tab away from the winding needle reached is defined as the ending point A of the A side of the first-layer positive electrode tab. 11 Then, the ending point A of the A side of the first-layer positive electrode tab can be used 11 as the starting point A of the A side of the second-layer positive electrode tab. 20 The starting point A of the A side of the second-layer positive electrode tab can be used 20 to rotate 360 degrees around the center point of the winding needle in the winding direction of the second-layer positive electrode tab along the edge line of the A side of the second-layer positive electrode tab away from the winding needle. The position on the edge line of the A side of the second-layer positive electrode tab away from the winding needle reached is defined as the ending point A of the A side of the second-layer positive electrode tab. 21 According to the same rule, the starting point A of the A side of the nth-layer positive electrode tab and the ending point A of the A side of the nth-layer positive electrode tab can be obtained. n0 n1 。

[0041] Optionally, the battery cell to be designed further includes multiple layers of separator, and the winding needle is also used for winding the multiple layers of separator. In one embodiment, obtaining the relationship between the length and areal density of multiple sets of electrode tabs of the battery cell to be designed in step S101 includes:

[0042] Obtaining the first target electrode tab surface located between the winding needle and the target point on the A side of the nth-layer positive electrode tab; the target point on the A side of the nth-layer positive electrode tab includes the starting point of the A side of the nth-layer positive electrode tab and the ending point of the A side of the nth-layer positive electrode tab;

[0043] Determining the first distance information between the A side of the nth-layer positive electrode tab and the winding needle according to the radius of the winding needle, the thickness of each layer of separator located between the winding needle and the target point on the A side of the nth-layer positive electrode tab, and the relationship between the thickness and areal density of the first target electrode tab surface; the first distance information includes the first distance between the starting point of the A side of the nth-layer positive electrode tab and the center point of the winding needle, and the second distance between the ending point of the A side of the nth-layer positive electrode tab and the center point.

[0044] Determine the relationship between the length of the A side and the areal density of the nth layer of the positive electrode tab based on the first distance, the first difference, and the first angular range corresponding to the A side of the nth layer of the positive electrode tab; the first difference is the difference between the second distance and the first distance; the first angular range is the range of the angle formed by taking the center point of the winding pin as the vertex, any point on the A side of the nth layer of the positive electrode tab, the center point of the winding pin, and the starting point of the A side of the nth layer of the positive electrode tab.

[0045] Please combine Figure 2 and Figure 3 , before the negative electrode tab and the positive electrode tab are wound around the winding pin synchronously, the number of layers of the negative electrode tab wound around the winding pin alone can be defined as the pre-winding number of layers of the negative electrode tab, and the number of layers of the separator wound around the winding pin before the negative electrode tab and the positive electrode tab are wound around the winding pin synchronously can be defined as the pre-winding number of layers of the separator. The pre-winding number of layers of the negative electrode tab with less than one full turn of pre-winding from the starting position of the single winding to the starting position of the synchronous winding of the negative electrode tab and the positive electrode tab can be regarded as 0, and the pre-winding number of layers of the separator with less than one full turn of pre-winding can be regarded as 0.

[0046] Specifically, when the target point of the A side of the nth layer of the positive electrode tab is the starting point of the A side of the nth layer of the positive electrode tab, if n = 1, the first target tab surface may include the following target tab surfaces: 1 C side and 1 D side of each pre-wound layer of the negative electrode tab, 1 C side and 1 D side of the 1st layer of the negative electrode tab, and 1 A side and 1 B side of the 1st layer of the positive electrode tab; if n > 1, the first target tab surface may include the following target tab surfaces: 1 C side and 1 D side of each pre-wound layer of the negative electrode tab, 1 C side and 1 D side of each layer of the negative electrode tab from the 1st layer to the nth layer of the negative electrode tab, and 1 A side and 1 B side of each layer of the positive electrode tab from the 1st layer to the nth layer of the positive electrode tab.

[0047] Specifically, when the target point of the A side of the nth layer of the positive electrode tab is the ending point of the A side of the nth layer of the positive electrode tab, if n = 1, the first target tab surface may include 1 C side and 1 D side of each pre-wound layer of the negative electrode tab, 2 C sides and 2 D sides of the 1st layer of the negative electrode tab, and 2 A sides and 2 B sides of the 1st layer of the positive electrode tab; if n > 1, the first target tab surface may include 1 C side and 1 D side of each pre-wound layer of the negative electrode tab, 1 C side and 1 D side of each layer of the negative electrode tab from the 1st layer to the n - 1th layer of the negative electrode tab, 2 C sides and 2 D sides of the nth layer of the negative electrode tab, 1 A side and 1 B side of each layer of the positive electrode tab from the 1st layer to the n - 1th layer of the positive electrode tab, and 2 A sides and 2 B sides of the nth layer of the positive electrode tab.

[0048] Optionally, the relationship between the thickness of the target tab surface and the areal density of the target tab surface is:

[0049] The thickness of the target tab surface = the areal density of the target tab surface / the compaction thickness + the foil thickness;

[0050] Among them, the compaction thickness and the foil thickness are invariant, and the foil thickness = the thickness of the current collector where the target electrode surface is located / 2.

[0051] Optionally, before the positive electrode sheet and the negative electrode sheet are wound around the winding needle synchronously, the thickness of the separator pre-wound between the negative electrode sheet and the winding needle, and between the positive electrode sheet and the negative electrode sheet is 2F; after the positive electrode sheet and the negative electrode sheet are wound around the winding needle synchronously, the thickness of the separator wound between the positive electrode sheet and the negative electrode sheet is F.

[0052] Optionally, through formulas (1), (2), and (3), determine the first distance r between the starting point of the A side of the nth layer of the positive electrode sheet and the winding needle An0 :

[0053] r An0 = R0 + F + tC n + TD n + TA n + TB n , n = 1 (1)

[0054]

[0055] Among them, TC n is the thickness of the C side of the nth layer of the negative electrode sheet, TD n is the thickness of the D side of the nth layer of the negative electrode sheet, TA n is the thickness of the A side of the nth layer of the negative electrode sheet, TB n is the thickness of the B side of the nth layer of the negative electrode sheet, TC i is the thickness of the C side of the ith layer of the negative electrode sheet, TD i is the thickness of the D side of the ith layer of the negative electrode sheet, TA i is the thickness of the A side of the ith layer of the positive electrode sheet, TB i is the thickness of the B side of the ith layer of the negative electrode sheet, Y is the number of pre-wound layers of the negative electrode sheet, TC j is the thickness of the C side of the jth pre-wound layer of the negative electrode sheet, TD j is the thickness of the D side of the jth pre-wound layer of the negative electrode sheet, W is the number of pre-wound layers of the separator, H is the radius of the winding needle; Y, TC j , TD j , W, Y, F, H are preset values; TC i , TD i , TA i , TB i , TC n , TD n , TA n , TB n can be expressed by the surface density of the corresponding surface based on the relationship between the thickness of the target electrode surface and the surface density of the target electrode surface.

[0056] Optionally, the second distance r between the end point of the A side of the nth-layer positive electrode tab and the winding pin is determined by formulas (3), (4), and (5). An1 :

[0057] r An1 = R0 + 3×F + 2×(TC n + TD n + TA n + TB n ), n = 1 (4)

[0058]

[0059] Next, the relationship between the length of the A side of the nth-layer negative electrode tab and the areal density of the A side can be determined by formulas (1) to (7):

[0060]

[0061] Δr An = r An1 - r An0 (7)

[0062] Wherein, LA n is the length of the A side of the nth-layer positive electrode tab, θ is the included angle formed by any point on the A side of the nth-layer positive electrode tab, the center point of the winding pin, and the starting point of the A side of the nth-layer positive electrode tab with the center point of the winding pin as the vertex. The range of this included angle is [θ An0 , θ An1 , θ An0 corresponds to the included angle at the starting point of the A side of the nth-layer positive electrode tab. Optionally, θ An0 = 0 degrees, θ An1 corresponds to the included angle at the end point of the A side of the nth-layer positive electrode tab. Optionally, θ An1 = 360 degrees.

[0063] In the embodiment of the present application, based on the thickness of the first target electrode tab surface between the A side of the nth-layer positive electrode tab and the winding pin, the first distance information between the A side of the nth-layer positive electrode tab and the winding pin is determined, and based on the first distance information between the A side of the nth-layer positive electrode tab and the winding pin, and the first angle range corresponding to the A side of the nth-layer positive electrode tab, the length of the A side of the arc-shaped nth-layer negative electrode tab is determined, so that through the relationship between the thickness of the target electrode tab surface and the areal density of the target electrode tab surface, the relationship between the length of the A side of the nth-layer positive electrode tab and the areal density of the A side can be accurately determined.

[0064] In one embodiment, obtaining the relationship between the lengths and areal densities of multiple groups of electrode tabs of the battery cell to be designed in step S101 includes:

[0065] Obtain the second target negative electrode surface located between the winding pin and the C-plane target point of the nth layer negative electrode sheet; the C-plane target point of the nth layer negative electrode sheet includes the C-plane starting point and the C-plane ending point of the nth layer negative electrode sheet;

[0066] Determine the second distance information between the C-plane of the nth layer negative electrode sheet and the winding pin according to the relationship between the thickness and the areal density of the second target negative electrode surface; the second distance information includes the third distance between the C-plane starting point of the nth layer negative electrode sheet and the center point of the winding pin, and the fourth distance between the C-plane ending point of the nth layer negative electrode sheet and the center point;

[0067] Determine the relationship between the length of the C-plane of the nth layer negative electrode sheet and the C-plane areal density according to the third distance, the second difference value, and the second angle range corresponding to the C-plane of the nth layer negative electrode sheet; the second difference value is the difference between the fourth distance and the third distance; the second angle range is the range of the included angle formed by any point on the C-plane of the nth layer negative electrode sheet, the center point of the winding pin, and the C-plane starting point of the nth layer negative electrode sheet with the center point of the winding pin as the vertex.

[0068] Specifically, when the C-plane target point of the nth layer negative electrode sheet is the C-plane starting point of the nth layer positive electrode sheet, if n = 1, the second target negative electrode surface may include the following target negative electrode surfaces: 1 C-plane and 1 D-plane of each pre-wound layer negative electrode sheet, and 1 C-plane of the first layer negative electrode sheet; if n > 1, the second target negative electrode surface may include 1 C-plane and 1 D-plane of each pre-wound layer negative electrode sheet, 1 C-plane and 1 D-plane of each layer negative electrode sheet from the first layer to the (n - 1)th layer negative electrode sheet, 1 A-plane and 1 B-plane of each layer positive electrode sheet from the first layer to the (n - 1)th layer positive electrode sheet, and 1 C-plane of the nth layer negative electrode sheet.

[0069] Specifically, when the C-plane target point of the nth layer negative electrode sheet is the C-plane ending point of the nth layer positive electrode sheet, if n = 1, the second target negative electrode surface may include the following target negative electrode surfaces: 1 C-plane and 1 D-plane of each pre-wound layer negative electrode sheet, 2 C-planes and 1 D-plane of the first layer negative electrode sheet, and 1 A-plane and 1 B-plane of the first layer positive electrode sheet; if n > 1, the second target negative electrode surface may include 1 C-plane and 1 D-plane of each pre-wound layer negative electrode sheet, 1 C-plane and 1 D-plane of each layer negative electrode sheet from the first layer to the (n - 1)th layer negative electrode sheet, 2 C-planes of the nth layer negative electrode sheet, 1 D-plane of the nth layer negative electrode sheet, and 1 A-plane and 1 B-plane of each layer positive electrode sheet from the first layer to the nth layer positive electrode sheet.

[0070] Optionally, determine the third distance r between the C-plane starting point of the nth layer negative electrode sheet and the winding pin through formulas (3), (8), and (9) Cn0 :

[0071] rCn0 = R0 + TC n , n = 1 (8)

[0072]

[0073] Wherein, TC n is the C - surface thickness of the n - th layer negative electrode tab, TC i is the C - surface thickness of the i - th layer negative electrode tab, TD i is the D - surface thickness of the i - th layer negative electrode tab, TA i is the A - surface thickness of the i - th layer positive electrode tab, TB i is the B - surface thickness of the i - th layer negative electrode tab; TC n , TC i , TD i , TA i , TB i can be expressed by the surface density of the corresponding surface based on the relationship between the thickness of the target tab surface and the surface density of the target tab surface.

[0074] Optionally, through formulas (3), (10), (11), determine the fourth distance r between the end point of the C - surface of the n - th layer negative electrode tab and the winding pin Cn1 :

[0075] r Cn1 = R0 + 2×F + TC n + TD n + TA n + TB n , n = 1 (10)

[0076]

[0077] Wherein, TD n is the D - surface thickness of the n - th layer negative electrode tab, TA n is the A - surface thickness of the n - th layer negative electrode tab, TB n is the B - surface thickness of the n - th layer negative electrode tab; TD n , TA n , TB n can be expressed by the surface density of the corresponding surface based on the relationship between the thickness of the target tab surface and the surface density of the target tab surface.

[0078] Next, through formulas (3), formula (8) - formula (13), determine the relationship between the C - surface length of the n - th layer negative electrode tab and the C - surface density:

[0079]

[0080] Δr Cn = r Cn1 - r Cn0(13)

[0081] Among them, LC n is the length of the C surface of the negative electrode tab of the nth layer, θ is the included angle formed by any point on the C surface of the negative electrode tab of the nth layer, the center point of the winding needle, and the starting point of the C surface of the negative electrode tab of the nth layer, and the range of this included angle is [θ Cn0 , θ Cn1 . θ Cn0 corresponds to the included angle at the starting point of the C surface of the negative electrode tab of the nth layer. Optionally, θ Cn0 = 0 degrees, θ Cn1 corresponds to the included angle at the ending point of the C surface of the negative electrode tab of the nth layer. Optionally, θθ Cn1 = 360 degrees.

[0082] In the embodiment of the present application, based on the thickness of the second target electrode surface between the C surface of the negative electrode tab of the nth layer and the winding needle, the first distance information between the C surface of the negative electrode tab of the nth layer and the winding needle is determined, and based on the first distance information between the C surface of the negative electrode tab of the nth layer and the winding needle, and the first angle range corresponding to the C surface of the negative electrode tab of the nth layer, the length of the C surface of the arc-shaped negative electrode tab of the nth layer is determined, so that through the relationship between the thickness of the target electrode surface and the surface density of the target electrode surface, the relationship between the length of the C surface of the negative electrode tab of the nth layer and the C surface density can be accurately determined.

[0083] In addition, for the relationship between the length of the B surface of the positive electrode tab of the nth layer and the B surface density, and the relationship between the length of the D surface of the negative electrode tab of the nth layer and the D surface density, reference can be made to the determination process of the relationship between the length of the A surface of the positive electrode tab of the nth layer and the A surface density, and / or the determination process of the relationship between the length of the C surface of the negative electrode tab of the nth layer and the C surface density in the above embodiment, which will not be elaborated here.

[0084] Next, the positive and negative capacity ratio corresponding to the nth group of electrode tabs can be determined through formulas (14) and (15):

[0085]

[0086] Among them, CB Cn+1 / An is the capacity ratio of the C surface of the (n + 1)th layer negative electrode tab to the A surface of the nth layer positive electrode tab in the nth group of electrode tabs, LC n+1 is the length of the C surface of the (n + 1)th layer negative electrode tab, σC n+1 is the C surface density of the (n + 1)th layer negative electrode tab, MC n+1 is the C surface gram capacity of the (n + 1)th layer negative electrode tab, PC n+1 is the C surface active material content of the (n + 1)th layer negative electrode tab, WC n+1 is the width of the C surface of the (n + 1)th layer negative electrode tab, LA n is the length of the A surface of the nth layer positive electrode tab, σAn is the areal density of the A side of the nth layer of the positive electrode sheet, MA n is the areal capacity of the A side of the nth layer of the positive electrode sheet, PA n is the active material content of the A side of the nth layer of the positive electrode sheet, WA n is the width of the A side of the nth layer of the positive electrode sheet. Among them, MC n+1 , PC n+1 , WC n+1 , σA n , MA n , PA n , WA n are set values, and LA n can be obtained by substituting σA n into formula (6).

[0087] CB Dn / Bn is the capacity ratio of the D side of the nth layer of the negative electrode sheet to the B side of the nth layer of the positive electrode sheet in the nth group of electrode sheets, LD n is the length of the D side of the nth layer of the negative electrode sheet, σD n is the areal density of the D side of the nth layer of the negative electrode sheet, MD n is the areal capacity of the D side of the nth layer of the negative electrode sheet, PD n is the active material content of the D side of the nth layer of the negative electrode sheet, WD n is the width of the D side of the nth layer of the negative electrode sheet, LB n is the length of the B side of the nth layer of the positive electrode sheet, σB n is the areal density of the B side of the nth layer of the positive electrode sheet, MB n is the areal capacity of the B side of the nth layer of the positive electrode sheet, PB n is the active material content of the B side of the nth layer of the positive electrode sheet, WB n is the width of the B side of the nth layer of the positive electrode sheet. Among them, MD n , PD n , WD n , σB n , MB n , PB n , WB n are set values, and LB n can be obtained by substituting σB n into the relational expression of the length and areal density of the B side of the nth layer of the positive electrode sheet.

[0088] Optionally, the positive and negative electrode capacity ratios corresponding to each group of electrode sheets in the above step S102 are equal, including: the capacity ratio of the C surface of the (n + 1)-th layer negative electrode sheet to the A surface of the n-th layer positive electrode sheet in the n-th group of electrode sheets is equal to the capacity ratio of the D surface of the n-th layer negative electrode sheet to the B surface of the n-th layer positive electrode sheet, and the capacity ratio of the C surface of the (n + 1)-th layer negative electrode sheet to the A surface of the n-th layer positive electrode sheet in the n-th group of electrode sheets is equal to the capacity ratio of the D surface of the (n + 1)-th layer negative electrode sheet to the B surface of the (n + 1)-th layer positive electrode sheet in the (n + 1)-th group of electrode sheets.

[0089] In one embodiment, step S102 is implemented: under the condition that the positive and negative electrode capacity ratios corresponding to each group of electrode sheets are equal, according to the relationship between the length and the areal density of the n-th group of electrode sheets, the areal density of the A surface and the areal density of the B surface of the n-th layer positive electrode sheet, and the areal density of the B surface of the (n + 1)-th layer positive electrode sheet, to determine the relationship between the areal density of the C surface of the (n + 1)-th layer negative electrode sheet and the areal density of the D surface of the n-th layer negative electrode sheet, and the relationship between the areal density of the C surface of the (n + 1)-th layer negative electrode sheet and the areal density of the D surface of the (n + 1)-th layer negative electrode sheet, including:

[0090] Optionally, let CB Dn / Bn = CB Cn+1 / An = CB Dn+1 / Bn+1 , based on the areal density σA n of the A surface, the areal density σB n of the B surface of the n-th layer positive electrode sheet, and the areal density σB n+1 of the B surface of the (n + 1)-th layer positive electrode sheet, referring to and combining the above formulas (1) to (15), to obtain the relationship between the areal density of the C surface of the (n + 1)-th layer negative electrode sheet and the areal density of the D surface of the n-th layer negative electrode sheet, and the relationship between the areal density of the C surface of the (n + 1)-th layer negative electrode sheet and the areal density of the D surface of the (n + 1)-th layer negative electrode sheet.

[0091] In one embodiment, in the above step S103, according to the relationship between the areal density of the C surface of the (n + 1)-th layer negative electrode sheet and the areal density of the D surface of the n-th layer negative electrode sheet, and the relationship between the areal density of the C surface of the (n + 1)-th layer negative electrode sheet and the areal density of the D surface of the (n + 1)-th layer negative electrode sheet, to determine the areal density of the C surface of the (n + 1)-th layer negative electrode sheet, the areal density of the D surface of the n-th layer negative electrode sheet, and the areal density of the D surface of the (n + 1)-th layer negative electrode sheet, including:

[0092] Set the areal density of the D surface of the first layer negative electrode sheet as the target areal density;

[0093] Based on the target areal density of the D surface of the first-layer negative electrode tab, the relationship between the areal density of the C surface of the (n + 1)-th layer negative electrode tab and the areal density of the D surface of the n-th layer negative electrode tab, and the relationship between the areal density of the C surface of the (n + 1)-th layer negative electrode tab and the areal density of the D surface of the (n + 1)-th layer negative electrode tab, determine the areal density of the C surface of the (n + 1)-th layer negative electrode tab, the areal density of the D surface of the n-th layer negative electrode tab, and the areal density of the D surface of the (n + 1)-th layer negative electrode tab.

[0094] In an embodiment of the present application, by assigning a value to the areal density of the D surface of the first-layer negative electrode tab, based on the relationship between the areal density of the C surface of the (n + 1)-th layer negative electrode tab and the areal density of the D surface of the n-th layer negative electrode tab, and the relationship between the areal density of the C surface of the (n + 1)-th layer negative electrode tab and the areal density of the D surface of the (n + 1)-th layer negative electrode tab, the areal density of the C surface of the (n + 1)-th layer negative electrode tab, the areal density of the D surface of the n-th layer negative electrode tab, and the areal density of the D surface of the (n + 1)-th layer negative electrode tab can be quickly determined, which can improve the efficiency of determining the areal density of the electrode tabs of the battery cell, and further improve the cycle performance and energy density of the battery cell designed based on the areal density of the electrode tabs.

[0095] In an embodiment, the step of determining the areal density of the C surface of the (n + 1)-th layer negative electrode tab, the areal density of the D surface of the n-th layer negative electrode tab, and the areal density of the D surface of the (n + 1)-th layer negative electrode tab according to the relationship between the areal density of the C surface of the (n + 1)-th layer negative electrode tab and the areal density of the D surface of the n-th layer negative electrode tab, and the relationship between the areal density of the C surface of the (n + 1)-th layer negative electrode tab and the areal density of the D surface of the (n + 1)-th layer negative electrode tab in step S103 includes:

[0096] According to the relationship between the areal density of the C surface of the (n + 1)-th layer negative electrode tab and the areal density of the D surface of the n-th layer negative electrode tab, the relationship between the areal density of the C surface of the (n + 1)-th layer negative electrode tab and the areal density of the D surface of the (n + 1)-th layer negative electrode tab, and the first preset relationship and / or the second preset relationship, determine the areal density of the C surface of the (n + 1)-th layer negative electrode tab, the areal density of the D surface of the n-th layer negative electrode tab, and the areal density of the D surface of the (n + 1)-th layer negative electrode tab;

[0097] Wherein, the first preset relationship is the preset relationship between the areal density of the C surface and the areal density of the D surface of the negative electrode tab of the same layer; the second preset relationship is the preset relationship between the areal densities of the same surface of the negative electrode tabs of different layers; the first preset relationship and the second preset relationship are set based on the positive-negative capacity ratio.

[0098] In the embodiments of the present application, by setting a first preset relationship and a second preset relationship for the positive and negative electrode capacity ratios, and adopting the first preset relationship and / or the second preset relationship, the relationship between the C-side area density of the negative electrode tab of the (n + 1)-th layer and the D-side area density of the negative electrode tab of the n-th layer, and the area density of the electrode tab of the battery cell that satisfies the relationship between the C-side area density of the negative electrode tab of the (n + 1)-th layer and the D-side area density of the negative electrode tab of the (n + 1)-th layer are found. It can ensure that the obtained area density can meet the design requirements of the battery cell, improve the efficiency and effect of determining the area density of the electrode tab of the battery cell, and further improve the cycle performance and energy density of the battery cell designed based on the area density of the electrode tab.

[0099] Optionally, the above-mentioned first preset relationship is that the proportion interval of the C-side area density of each layer of negative electrode tab is [45%, 50%).

[0100] Optionally, the above-mentioned second preset relationship is that the area densities of the same side of different layers of negative electrode tabs are not equal, and the deviation of the C-side area densities of adjacent two layers of negative electrode tabs is less than or equal to 2%.

[0101] In the embodiments of the present application, by setting the above-mentioned first preset relationship as the proportion interval of the C-side area density of each layer of negative electrode tab being [45%, 50%), and setting the second preset relationship as the area densities of the same side of different layers of negative electrode tabs being not equal, and the deviation of the C-side area densities of adjacent two layers of negative electrode tabs being less than or equal to 2%, the area density obtained by solving based on the above-mentioned step S103 can not only meet the condition that the positive and negative electrode capacity ratios corresponding to each group of electrode tabs of the battery cell are equal, but also make the positive and negative electrode capacity ratio within the range of [1.01, 1.2], so that the battery cell designed based on this area density has better cycle performance and energy density.

[0102] In one embodiment, after obtaining the relationship between the length and area density of the n-th group of electrode tabs of the battery cell to be designed in the above-mentioned step S101, the parameter determination method provided by the embodiments of the present application further includes:

[0103] Set the positive and negative electrode capacity ratio as the target capacity ratio;

[0104] According to the target capacity ratio, the relationship between the A-side length and A-side area density of the n-th layer of positive electrode tab, the relationship between the C-side length and C-side area density of the (n + 1)-th layer of negative electrode tab, and the A-side area density of the n-th layer of positive electrode tab, determine the C-side area density of the (n + 1)-th layer of negative electrode tab;

[0105] According to the target capacity ratio, the relationship between the B-side length and B-side area density of the n-th layer of positive electrode tab, the relationship between the D-side length and D-side area density of the n-th layer of negative electrode tab, and the B-side area density of the n-th layer of positive electrode tab, determine the D-side area density of the n-th layer of negative electrode tab.

[0106] Optionally, let CB Dn / Bn = CBCn+1 / An = CB 0 , through CB Cn+1 / An = CB 0 , substitute the A-side areal density of the nth layer of the positive electrode sheet into the above formula (14), and solve to obtain the C-side areal density of the (n + 1)th layer of the negative electrode sheet; through CB Dn / Bn = CB 0 , substitute the B-side areal density of the nth layer of the positive electrode sheet into the above formula (14), and solve to obtain the C-side areal density of the (n + 1)th layer of the negative electrode sheet.

[0107] In the embodiments of the present application, the positive-to-negative capacity ratios corresponding to each group of electrode sheets are set to the target capacity ratio. On the one hand, based on the target capacity ratio, the areal density of the electrode sheets of the battery cell can be directly solved. On the other hand, it can ensure that for the battery cell designed based on the solved areal density, the positive-to-negative capacity ratios corresponding to each group of electrode sheets are equal, which can improve the efficiency and effect of determining the areal density of the electrode sheets of the battery cell, and further improve the cycle performance and energy density of the battery cell designed based on the areal density of the electrode sheets.

[0108] In an embodiment, after determining the C-side areal density of the (n + 1)th layer of the negative electrode sheet, the D-side areal density of the nth layer of the negative electrode sheet, and the D-side areal density of the (n + 1)th layer of the negative electrode sheet in the above step S103, the parameter determination method provided by the embodiments of the present application further includes:

[0109] According to the C-side areal density of the (n + 1)th layer of the negative electrode sheet and the relationship between the C-side length and the C-side areal density of the (n + 1)th layer of the negative electrode sheet, determine the C-side length of the (n + 1)th layer of the negative electrode sheet;

[0110] According to the D-side areal density of the nth layer of the negative electrode sheet and the relationship between the D-side length and the D-side areal density of the nth layer of the negative electrode sheet, determine the D-side length of the nth layer of the negative electrode sheet.

[0111] Optionally, after determining the C-side areal density of the (n + 1)th layer of the negative electrode sheet, the C-side areal density of the (n + 1)th layer of the negative electrode sheet can be substituted into the relationship between the C-side length and the C-side areal density of the (n + 1)th layer of the negative electrode sheet to obtain the C-side length of the (n + 1)th layer of the negative electrode sheet. Similarly, after determining the D-side areal density of the nth layer of the negative electrode sheet, the D-side areal density of the nth layer of the negative electrode sheet can be substituted into the relationship between the D-side length and the D-side areal density of the nth layer of the negative electrode sheet to obtain the D-side length of the nth layer of the negative electrode sheet.

[0112] Based on accurately constructing the relationship between the length and areal density of the arc-shaped electrode tab, by solving for the areal density of the electrode tab that makes the positive and negative capacity ratios of the electrode tabs in each group of the battery cell equal, the length of each side of the arc-shaped electrode tab can be accurately solved. Moreover, for the battery wire designed based on the solved length of each side of the electrode tab, the positive and negative capacity ratios of the electrode tabs in each group are also equal. This can improve the efficiency and effectiveness of determining the areal length of the electrode tab of the battery cell, and further improve the cycle performance and energy density of the battery cell designed based on the areal length of the electrode tab.

[0113] Optionally, under the given conditions: the areal density of the A side of each layer of the positive electrode tab = the areal density of the B side of each layer of the positive electrode tab = 10.65 mg / cm 2 , the thickness of the A side of each layer of the positive electrode tab = the thickness of the B side of each layer of the positive electrode tab = 0.025 mm, the areal density of the C side of the first layer of the negative electrode tab = 4.60 mg / cm 2 , the thickness of the C side of the first layer of the negative electrode tab = 0.029 mm, the areal density of the D side of the first layer of the negative electrode tab = 4.80 mg / cm 2 , the thickness of the D side of the first layer of the negative electrode tab = 0.031 mm, the relationship of the areal length of the electrode tab obtained by the method for determining the parameters of the battery cell provided by the embodiments of the present application is as Figure 4a shown: the areal length of the D side of the nth layer of the negative electrode tab and the areal length of the B side of the nth layer of the positive electrode tab decrease as the value of n increases; the areal length of the C side of the (n + 1)th layer of the negative electrode tab and the areal length of the A side of the nth layer of the positive electrode tab increase as the value of n increases; the relationship of the areal density of the negative electrode tab obtained by the method for determining the parameters of the battery cell provided by the embodiments of the present application is as Figure 4b shown: the areal density of the D side of the nth layer of the negative electrode tab decreases as the value of n increases; the areal density of the C side of the nth layer of the negative electrode tab increases as the value of n increases; for the battery cell designed based on the areal length of the electrode tab in Figure 4a and the areal density of the electrode tab in Figure 4b , the positive and negative capacity ratios thereof satisfy the following relationship: CB Dn / Bn = CB Cn+1 / An = 1.03, that is, as Figure 4c shown: the design average value CB = 1.03, CB min = 1.03, CB max = 1.03, and its energy density = 54.62 mAh.

[0114] As Figure 5a shown, under the parameters set by the conventional method for determining parameters: the areal density of the A side of each layer of the positive electrode tab = the areal density of the B side of each layer of the positive electrode tab 10.65 mg / cm 2 , the thickness of the A side of each layer of the positive electrode tab = the thickness of the B side of each layer of the positive electrode tab = 0.025 mm; the areal density of the C side of each layer of the negative electrode tab = the areal density of the D side of each layer of the negative electrode tab = 4.89 mg / cm2 , on the basis that the C surface of each layer of the negative electrode tab = the D surface thickness of each layer of the negative electrode tab = 0.0311 mm, a battery cell is designed, and the positive and negative capacity ratios corresponding to each electrode tab group are not equal. The average value of the positive and negative capacity ratios corresponding to each electrode tab group, CB = 1.075, and the minimum value, CB min = 1.031, the maximum value, CBmax = 1.117, and its energy density = 53.48 mAh.

[0115] As Figure 5b shown, under the parameters set by another conventional parameter determination method: the areal density of the A surface of each layer of the positive electrode tab = the areal density of the B surface of each layer of the positive electrode tab = 10.65 mg / cm 2 , the thickness of the A surface of each layer of the positive electrode tab = the thickness of the B surface of each layer of the positive electrode tab = 0.025 mm; the areal density of the C surface of each layer of the negative electrode tab = 4.66 mg / cm 2 , the areal density of the D surface of each layer of the negative electrode tab = 4.89 mg / cm 2 , on the basis that the C surface of each layer of the negative electrode tab = 0.0297 mm and the D surface thickness of each layer of the negative electrode tab = 0.0311 mm, a battery cell is designed, and the positive and negative capacity ratios corresponding to each electrode tab group are not equal. The average value of the positive and negative capacity ratios corresponding to each electrode tab group is set as CB = 1.05, and the minimum value, CB min = 1.031, and the maximum value, CB max = 1.07, and its energy density = 54.22 mAh.

[0116] As shown in the following table, 5 sets of scheme groups are designed based on the parameters obtained by the parameter determination method provided in this application, and 5 sets of control groups are designed based on the parameters obtained by the conventional parameter determination method. By comparing the implementation data of the 5 sets of scheme groups and the 5 sets of control groups, it can be seen that the energy density (Energy Density, ED) of the battery cells corresponding to the 5 sets of scheme groups is higher than that of the battery cells corresponding to the 5 sets of control groups, indicating that the electrode tab areal density obtained by the battery cell parameter determination method provided in the embodiments of this application can be used to design battery cells with higher energy density.

[0117]

[0118] The embodiments of this application also provide a parameter determination system for a battery cell. The battery cell to be designed includes a winding pin, multiple layers of positive electrode tabs, and multiple layers of negative electrode tabs; the winding pin is used to wind the multiple layers of positive electrode tabs and the multiple layers of negative electrode tabs; each layer of the positive electrode tab includes an A surface facing away from the winding pin and a B surface facing the winding pin; each layer of the negative electrode tab includes a C surface facing the winding pin and a D surface facing away from the winding pin. As Figure 6 shown, the parameter determination system for a battery cell provided in the embodiments of this application may include: an acquisition module, a first determination module, and a second determination module.

[0119] Among them, the acquisition module is used to acquire the relationship between the length and areal density of the nth set of electrode plates of the battery cell to be designed; the relationship between the length and areal density of the nth set of electrode plates includes the relationship between the length of the A side and the areal density of the A side of the nth layer of positive electrode plates, the relationship between the length of the B side and the areal density of the B side of the nth layer of positive electrode plates, the relationship between the length of the C side and the areal density of the C side of the (n + 1)th layer of negative electrode plates, and the relationship between the length of the D side and the areal density of the D side of the nth layer of negative electrode plates; the nth layer of positive electrode plates is located between the nth layer of negative electrode plates and the (n + 1)th layer of negative electrode plates; n is a positive integer;

[0120] The first determination module is used to determine the relationship between the areal density of the C side of the (n + 1)th layer of negative electrode plates and the areal density of the D side of the nth layer of negative electrode plates, and the relationship between the areal density of the C side and the areal density of the D side of the (n + 1)th layer of negative electrode plates according to the relationship between the length and areal density of the nth set of electrode plates, the areal density of the A side and the areal density of the B side of the nth layer of positive electrode plates, and the areal density of the B side of the (n + 1)th layer of positive electrode plates under the condition that the positive-negative capacity ratios corresponding to each set of electrode plates are equal;

[0121] The second determination module is used to determine the areal density of the C side of the (n + 1)th layer of negative electrode plates, the areal density of the D side of the nth layer of negative electrode plates, and the areal density of the D side of the (n + 1)th layer of negative electrode plates according to the relationship between the areal density of the C side of the (n + 1)th layer of negative electrode plates and the areal density of the D side of the nth layer of negative electrode plates, and the relationship between the areal density of the C side and the areal density of the D side of the (n + 1)th layer of negative electrode plates.

[0122] The parameter determination system of the nuclear power unit provided by the embodiments of the present application can implement each step of the above-mentioned parameter determination method embodiment of the battery cell, and can achieve the same technical effect. To avoid repetition, it will not be elaborated here.

[0123] Optionally, the embodiments of the present application further provide a battery cell, and the battery cell includes the parameters determined by the above-mentioned parameter determination method of the battery cell.

[0124] Optionally, the embodiments of the present application further provide an electronic device, including a processor and a memory. A program or instruction that can run on the processor is stored on the memory. When the program or instruction is executed by the processor, each step of the above-mentioned parameter determination method embodiment of the battery cell is implemented, and the same technical effect can be achieved. To avoid repetition, it will not be elaborated here. It should be noted that the electronic device in the embodiments of the present application includes the above-mentioned mobile electronic device and non-mobile electronic device.

[0125] Figure 7 To implement the hardware structure diagram of the electronic device in the embodiments of the present application, the electronic device includes:

[0126] The processor 701 can be implemented in the form of a general-purpose central processing unit (CPU), a microprocessor, an application specific integrated circuit (ASIC), or one or more integrated circuits, etc., and is used to execute relevant programs to implement the technical solutions provided in the embodiments of the present application;

[0127] The memory 702 can be implemented in the form of a read-only memory (ROM), a static storage device, a dynamic storage device, or a random access memory (RAM), etc. The memory 702 can store an operating system and other application programs. When implementing the technical solutions provided in the embodiments of this specification through software or firmware, the relevant program codes are stored in the memory 702 and are called by the processor 701 to execute the method for determining the parameters of the battery cell in the embodiments of the present application;

[0128] The input / output interface 703 is used to implement information input and output;

[0129] The communication interface 704 is used to implement communication interaction between this device and other devices, and can achieve communication through wired means (such as USB, network cable, optical fiber, etc.);

[0130] The bus 707 transmits information between the various components of the device (such as the processor 701, the memory 702, the input / output interface 703, and the communication interface 704);

[0131] Among them, the processor 701, the memory 702, the input / output interface 703, and the communication interface 704 are communicatively connected to each other inside the device through the bus 707.

[0132] The electronic device provided in the embodiments of the present application can implement each step of the method embodiment for determining the parameters of the battery cell as described above, and can achieve the same technical effects. To avoid repetition, it will not be elaborated here.

[0133] The embodiments of the present application further provide a computer-readable storage medium. A program or instruction is stored on the computer-readable storage medium. When the program or instruction is executed by a processor, each step of the method embodiment for determining the parameters of the battery cell as described above is implemented, and the same technical effects can be achieved. To avoid repetition, it will not be elaborated here.

[0134] Among them, the processor is the processor in the electronic device described in the above embodiments. The computer-readable storage medium includes computer-readable storage media, such as computer read-only memory ROM, random access memory RAM, magnetic disks, or optical discs, etc.

[0135] Another embodiment of the present application further provides a chip, which includes a processor and a communication interface. The communication interface is coupled to the processor. The processor is configured to run programs or instructions to implement the various steps of the above-described embodiment of the method for determining parameters of the battery cell, and can achieve the same technical effects. To avoid repetition, details are not described herein again.

[0136] It should be understood that the chip mentioned in the embodiments of the present application may also be referred to as a system-on-chip, system chip, chip system, or system-on-a-chip, etc.

[0137] The embodiments of the present application provide a computer program product, which is stored in a storage medium and is executed by at least one processor to implement the various steps of the above-described embodiment of the method for determining parameters of the battery cell, and can achieve the same technical effects. To avoid repetition, details are not described herein again.

[0138] It should be noted that in this article, the terms "include", "comprise" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "including one..." does not exclude the existence of additional identical elements in the process, method, article or device including that element. In addition, it should be pointed out that the methods and devices in the embodiments of the present application are not limited to performing functions in the order shown or discussed, and may also include performing functions in a substantially simultaneous manner or in a reverse order according to the functions involved. For example, the described methods may be performed in an order different from that described, and various steps may be added, omitted, or combined. Additionally, the features described with reference to certain examples may be combined in other examples.

[0139] Through the description of the above embodiments, those skilled in the art can clearly understand that the above-described embodiment methods can be implemented by means of software plus a necessary general hardware platform. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation. Based on such an understanding, the technical solution of the present application, in essence, or the part that contributes to the prior art, can be embodied in the form of a computer software product. The computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disc) and includes several instructions for causing a terminal (which may be a computer, a server, or a network device, etc.) to execute the methods described in the various embodiments of the present application.

[0140] The embodiments of the present application have been described above in conjunction with the accompanying drawings. However, the present application is not limited to the above specific embodiments. The above specific embodiments are merely illustrative rather than restrictive. Under the inspiration of the present application, those of ordinary skill in the art can also make many forms without departing from the purpose of the present application and the scope protected by the claims, and all of them fall within the protection scope of the present application.

Claims

1. A method for determining parameters of a battery cell, characterized in that: The battery cell to be designed includes a winding needle, a multi-layer positive electrode sheet and a multi-layer negative electrode sheet, wherein the winding needle is used to wind the multi-layer positive electrode sheet and the multi-layer negative electrode sheet; each layer of the positive electrode sheet includes an A surface facing away from the winding needle and a B surface facing the winding needle; each layer of the negative electrode sheet includes a C surface facing the winding needle and a D surface facing away from the winding needle; the parameter determination method includes: Obtaining the relationship between the length and the surface density of the nth group of pole pieces of the battery cell to be designed; the relationship between the length and the surface density of the nth group of pole pieces includes the relationship between the length of the A surface of the nth layer of positive pole pieces and the surface density of the A surface, the relationship between the length of the B surface of the nth layer of positive pole pieces and the surface density of the B surface, the relationship between the length of the C surface of the n+1th layer of negative pole pieces and the surface density of the C surface, and the relationship between the length of the D surface of the nth layer of negative pole pieces and the surface density of the D surface; the nth layer of positive pole pieces is located between the nth layer of negative pole pieces and the n+1th layer of negative pole pieces; n is a positive integer; Under the condition that the positive and negative electrode capacity ratios corresponding to each group of electrode sheets are equal, the relationship between the surface density of the C surface of the n+1th layer of negative electrode sheet and the surface density of the D surface of the nth layer of negative electrode sheet, and the relationship between the surface density of the C surface of the n+1th layer of negative electrode sheet and the surface density of the D surface of the n+1th layer of negative electrode sheet are determined according to the relationship between the length and surface density of the nth group of electrode sheets, the surface density of the A surface and the surface density of the B surface of the n+1th layer of positive electrode sheet; According to the relationship between the C-surface density of the n+1-th layer of negative electrode pole sheet and the D-surface density of the n-th layer of negative electrode pole sheet, and the relationship between the C-surface density of the n+1-th layer of negative electrode pole sheet and the D-surface density of the n+1-th layer of negative electrode pole sheet, the C-surface density of the n+1-th layer of negative electrode pole sheet, the D-surface density of the n-th layer of negative electrode pole sheet and the D-surface density of the n+1-th layer of negative electrode pole sheet are determined.

2. The parameter determination method according to claim 1, characterized in that: The battery cell to be designed further comprises a multi-layer separator; the winding needle is further used to wind the multi-layer separator; the step of obtaining the relationship between the length and the surface density of the plurality of pole pieces of the battery cell to be designed comprises: Acquire a first target electrode sheet surface between the winding needle and the target point on the A surface of the n-th layer of positive electrode sheet; the target point on the A surface of the n-th layer of positive electrode sheet includes the starting point on the A surface of the n-th layer of positive electrode sheet and the ending point on the A surface of the n-th layer of positive electrode sheet; Determine the first distance information between the surface A of the n-th layer of positive electrode sheet and the winding needle according to the radius of the winding needle, the thickness of each layer of the diaphragm between the winding needle and the target point of the surface A of the n-th layer of positive electrode sheet, and the relationship between the thickness of the first target electrode sheet surface and the surface density of the first target electrode sheet surface; the first distance information includes a first distance between the starting point of the surface A of the n-th layer of positive electrode sheet and the center point of the winding needle, and a second distance between the end point of the surface A of the n-th layer of positive electrode sheet and the center point; According to the first distance, the first difference and the first angle range corresponding to the A surface of the n-th layer of the positive electrode sheet, the relationship between the length of the A surface of the n-th layer of the positive electrode sheet and the A surface density is determined; the first difference is the difference between the second distance and the first distance; the first angle range is the range of the angle formed by any point on the A surface of the n-th layer of the positive electrode sheet, the center point of the winding needle and the starting point of the A surface of the n-th layer of the positive electrode sheet with the center point of the winding needle as the vertex.

3. The parameter determination method according to claim 1, characterized in that: After determining the surface density of the C surface of the negative electrode sheet of the n+1th layer, the surface density of the D surface of the negative electrode sheet of the nth layer, and the surface density of the D surface of the negative electrode sheet of the n+1th layer, the parameter determination method further includes: Determine the C-surface length of the n+1-th layer of negative electrode sheet according to the C-surface surface density of the n+1-th layer of negative electrode sheet and the relationship between the C-surface length of the n+1-th layer of negative electrode sheet and the C-surface surface density; The D-surface length of the n-th layer of negative electrode sheet is determined according to the D-surface surface density of the n-th layer of negative electrode sheet and the relationship between the D-surface length of the n-th layer of negative electrode sheet and the D-surface surface density.

4. The parameter determination method according to claim 1, characterized in that: Determining the C surface density of the n+1th layer of negative electrode sheet, the D surface density of the nth layer of negative electrode sheet, and the D surface density of the n+1th layer of negative electrode sheet according to the relationship between the C surface density of the n+1th layer of negative electrode sheet and the D surface density of the n+1th layer of negative electrode sheet, comprises: Determine the C surface density of the negative electrode sheet of the n+1th layer, the D surface density of the negative electrode sheet of the nth layer, and the D surface density of the negative electrode sheet of the n+1th layer according to the relationship between the C surface density of the negative electrode sheet of the n+1th layer and the D surface density of the negative electrode sheet of the n+1th layer, and the first preset relationship and / or the second preset relationship; Among them, the first preset relationship is the preset relationship between the surface density of the C surface and the surface density of the D surface of the same layer of negative electrode sheets; the second preset relationship is the preset relationship between the surface density of the same surface of different layers of negative electrode sheets; the first preset relationship and the second preset relationship are set based on the positive and negative electrode capacity ratio.

5. The parameter determination method according to claim 4, characterized in that: The first preset relationship is that the C-surface density of each layer of negative electrode sheet accounts for a range of [45%, 50%); The second preset relationship is that the surface densities of the same surface of different layers of negative electrode sheets are not equal, and the deviation of the surface density of the C surface of two adjacent layers of negative electrode sheets is less than or equal to 2%.

6. The parameter determination method according to claim 1, characterized in that: After obtaining the relationship between the length and the surface density of the nth group of pole pieces of the battery cell to be designed, the parameter determination method further includes: Setting the positive and negative electrode capacity ratio to a target capacity ratio; Determine the C surface density of the n+1th layer of negative electrode sheet according to the target capacity ratio, the relationship between the A surface length and the A surface density of the nth layer of positive electrode sheet, the relationship between the C surface length and the C surface density of the n+1th layer of negative electrode sheet, and the A surface density of the nth layer of positive electrode sheet; The D surface density of the nth layer of negative electrode sheet is determined based on the target capacity ratio, the relationship between the B surface length and the B surface density of the nth layer of positive electrode sheet, the relationship between the D surface length and the D surface density of the nth layer of negative electrode sheet, and the B surface density of the nth layer of positive electrode sheet.

7. A battery cell parameter determination system, characterized in that: The battery cell to be designed includes a winding needle, a multi-layer positive electrode sheet and a multi-layer negative electrode sheet; the winding needle is used to wind the multi-layer positive electrode sheet and the multi-layer negative electrode sheet; each layer of the positive electrode sheet includes an A surface facing away from the winding needle and a B surface facing the winding needle; each layer of the negative electrode sheet includes a C surface facing the winding needle and a D surface facing away from the winding needle; the parameter determination system includes: an acquisition module, a first determination module and a second determination module; The acquisition module is used to obtain the relationship between the length and surface density of the nth group of pole pieces of the battery cell to be designed; the relationship between the length and surface density of the nth group of pole pieces includes the relationship between the length of the A surface of the nth layer of positive pole pieces and the surface density of the A surface, the relationship between the length of the B surface of the nth layer of positive pole pieces and the surface density of the B surface, the relationship between the length of the C surface of the n+1th layer of negative pole pieces and the surface density of the C surface, and the relationship between the length of the D surface of the nth layer of negative pole pieces and the surface density of the D surface; the nth layer of positive pole pieces is located between the nth layer of negative pole pieces and the n+1th layer of negative pole pieces; n is a positive integer; The first determination module is used to determine the relationship between the surface density of the C surface of the n+1th layer of negative electrode sheet and the surface density of the D surface of the nth layer of negative electrode sheet, and the relationship between the surface density of the C surface of the n+1th layer of negative electrode sheet and the surface density of the D surface of the n+1th layer of negative electrode sheet, under the condition that the positive and negative electrode capacity ratios corresponding to each group of electrode sheets are equal, according to the relationship between the length and surface density of the nth group of electrode sheets, the surface density of the A surface and the surface density of the B surface of the n+1th layer of positive electrode sheet, and the surface density of the B surface of the n+1th layer of positive electrode sheet; The second determination module is used to determine the C surface density of the n+1th layer of negative electrode pole sheet, the D surface density of the nth layer of negative electrode pole sheet and the D surface density of the n+1th layer of negative electrode pole sheet based on the relationship between the C surface density of the n+1th layer of negative electrode pole sheet and the D surface density of the n+1th layer of negative electrode pole sheet, and the relationship between the C surface density of the n+1th layer of negative electrode pole sheet and the D surface density of the n+1th layer of negative electrode pole sheet.

8. An electronic device, characterized in that: The electronic device comprises a memory and a processor, wherein the memory stores a computer program, and the processor implements the parameter determination method according to any one of claims 1 to 6 when executing the computer program.

9. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the parameter determination method according to any one of claims 1 to 6 is implemented.

10. A battery cell, characterized in that: The battery cell includes parameters determined by the parameter determination method according to any one of claims 1 to 6.

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