Winding battery cell and battery
By adding a granular layer at the corner of the cathode electrode and setting a high-capacity material layer on the anode electrode, the problems of insufficient electrolyte wetting and lithium plating are solved, thereby improving the electrical stability and lifespan of the battery.
Patent Information
- Application Number
- CN202423057777.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-11
- Publication Date
- 2025-12-19
- Estimated Expiration
- 2034-12-11
AI Technical Summary
In existing wound battery cells, the gap between the electrode and the separator at the corner is small, resulting in insufficient electrolyte wetting, easy lithium deposition, and reduced CB value.
A granular layer is added at the corner of the cathode electrode, and a second anode active material layer with a specific capacity higher than that of the first anode active material layer is set at the corresponding position of the anode electrode to increase the gap between the cathode electrode and the separator and enhance the CB value at the corner.
It improves electrolyte wetting, reduces lithium plating at corners, and enhances the battery's electrical stability and cycle life.
Smart Images
Figure CN223693167U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of lithium batteries, and more particularly relates to a wound battery cell and a battery. BACKGROUND
[0002] In the prior art, the corner position tension of a conventional wound structure battery cell is relatively large during winding, and the gap between the electrode plate and the separator in the corner position is smaller than that in the flat area, so that the electrolyte may be insufficiently infiltrated, and lithium may be easily separated. Due to the influence of the wound structure itself, the cathode long film surface is wrapped around the anode at the outer circle, and due to the influence of the curvature radius, the arc length of the outer circle cathode electrode plate is greater than that of the inner circle anode electrode plate, so that the CB value is reduced, which is an important factor for lithium separation at the corner. CONTENT OF THE UTILITY MODEL
[0003] One object of the application is to provide a wound battery cell to solve the technical problem that the gap between the electrode plate and the separator in the corner position of the wound structure battery cell in the prior art is smaller than that in the flat area, the CB value is reduced, the electrolyte may be insufficiently infiltrated, and lithium may be easily separated.
[0004] Another object of the application is to provide a battery.
[0005] To achieve the above object, the technical scheme adopted by the application is:
[0006] The application provides a wound battery cell, which comprises a cathode electrode plate, a separator and an anode electrode plate which are sequentially stacked and wound.
[0007] The cathode electrode plate comprises a cathode base body, a cathode active material layer and a particle layer, the cathode active material layer is attached to at least one side of the cathode base body in the thickness direction, and the particle layer is embedded between the cathode base body and the cathode active material layer and located at the corner of the cathode base body.
[0008] The anode electrode plate comprises an anode base body, a first anode active material layer and a second anode active material layer, the first anode active material layer is attached to at least one side of the anode base body in the thickness direction, the second anode active material layer is arranged between the anode base body and the first anode active material layer, and the position of the second anode active material layer corresponds to that of the particle layer, and the gram capacity of the second anode active material layer is greater than that of the first anode active material layer.
[0009] Optionally, the particles in the particle layer are ceramic particles.
[0010] Optionally, the porosity of the particle layer is (40±5) %.
[0011] Optionally, the particle size of the particles in the particle layer is 0.1-5 mu m.
[0012] Optionally, the thickness of the particle layer is 10% of the thickness of the cathode active material layer.
[0013] Optionally, the cathode electrode sheet, the separator and the anode electrode sheet are all wound in multiple layers, the cathode electrode sheet has N corners, N is a positive integer, D is the sum of the thickness of the separator and the thickness of the anode electrode sheet, the first corner is ranked outward from the end of the cathode electrode sheet closest to the center along the winding direction, and the length L1 of the particle layer of the first corner is π*D / 2.
[0014] Optionally, T is the sum of the thickness of two layers of the separator, the thickness of one layer of the anode electrode sheet and the thickness of one layer of the cathode electrode sheet, and the length L N of the particle layer of the Nth corner is π*[D+(N-1)T] / 2.
[0015] Optionally, the second anode active material layer is embedded in the first anode active material layer, and the end surface of the second anode active material layer is flush with the end surface of the first anode active material layer.
[0016] Optionally, the ratio of the gram capacity of the first anode active material layer to the gram capacity of the second anode active material layer is 97.7%-99.5%.
[0017] Optionally, the cathode electrode sheet, the separator and the anode electrode sheet are all wound in multiple layers, the anode electrode sheet has M corners, M is a positive integer, B is the sum of the thickness of one layer of the separator and the thickness of one layer of the anode matrix, the first corner is ranked outward from the end of the anode electrode sheet closest to the center along the winding direction, and the length S of the second anode active material layer of the first corner is π*B / 2.
[0018] Optionally, P is the sum of the thickness of two layers of the separator, the thickness of one layer of the anode electrode sheet and the thickness of one layer of the cathode electrode sheet, and the length S M of the second anode active material layer of the Mth corner is π*[B+(M-1)P] / 2.
[0019] And, a battery is provided, comprising the above-mentioned wound battery cell.
[0020] The wound battery cell and the battery provided by the present application have the following beneficial effects:
[0021] The wound battery cell provided by the present application increases the particle layer at the corner position of the cathode electrode sheet, the particles in the particle layer have gaps between them, which increases the gap between the cathode electrode sheet and the separator, improves the infiltration of the electrolyte, and at the same time, the anode electrode sheet is provided with the second anode active material layer with higher gram capacity than the first anode active material layer at the position corresponding to the particle layer, which improves the CB value of the wound battery cell at the corner position, thereby improving the problem of lithium precipitation at the corner of the wound battery cell;
[0022] The battery of the application is made of the winding battery cell provided by the application, the electrolyte of the winding battery cell is fully infiltrated, the problem of corner lithium precipitation is effectively improved, and the electrical stability and cycle life of the battery are improved. BRIEF DESCRIPTION OF DRAWINGS
[0023] In order to more clearly illustrate the technical solutions in the embodiments of the application, the drawings needed to be used in the embodiments or prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can be obtained by those skilled in the art without creative labor.
[0024] Figure 1 The structure schematic diagram of the winding battery cell provided by the embodiments of the application is shown in the figure.
[0025] Figure 2 For Figure 1 The enlarged view of the A part in the winding battery cell is shown in the figure.
[0026] Figure 3 The structure schematic diagram of the cathode tab in the winding battery cell provided by the embodiments of the application is shown in the figure.
[0027] Figure 4 The structure schematic diagram of the anode tab in the winding battery cell provided by the embodiments of the application is shown in the figure.
[0028] In the figure, various reference signs are as follows:
[0029] 10, cathode tab; 11, cathode substrate; 12, cathode active material layer; 13, particle layer;
[0030] 20, anode tab; 21, anode substrate; 22, first anode active material layer; 23, second anode active material layer;
[0031] 30, separator. DETAILED DESCRIPTION
[0032] In order to make the technical problems, technical solutions and beneficial effects of the application more clearly understood, the application will be further described in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the application and not to limit the application.
[0033] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.
[0034] It should be understood that the terms "length", "width", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application.
[0035] In addition, the terms "first", "second" are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise specifically limited.
[0036] Please refer to Figures 1 to 4 The winding battery provided by the embodiment of the present application will be described below, which comprises a cathode pole piece 10, a separator 30 and an anode pole piece 20 which are stacked in sequence and wound with each other.
[0037] The cathode pole piece 10 comprises a cathode base body 11, a cathode active material layer 12 and a particle layer 13, the cathode active material layer 12 is attached to at least one side of the thickness of the cathode base body 11, and the particle layer 13 is embedded between the cathode base body 11 and the cathode active material layer 12 and located at the corner of the cathode base body 11.
[0038] The anode pole piece 20 comprises an anode base body 21, a first anode active material layer 22 and a second anode active material layer, the first anode active material layer 22 is attached to at least one side of the thickness of the anode base body 21, and the second anode active material layer is arranged between the anode base body 21 and the first anode active material layer 22, and the position of the second anode active material layer corresponds to that of the particle layer 13, and the gram capacity of the second anode active material layer is greater than that of the first anode active material layer 22.
[0039] The winding battery of the embodiment of the present application increases the particle layer 13 at the corner position of the cathode pole piece 10, the particles in the particle layer 13 have gaps between them, which increases the gap between the cathode pole piece 10 and the separator 30, improves the infiltration of the electrolyte, at the same time, the second anode active material layer 23 with a gram capacity higher than that of the first anode active material layer 22 is arranged at the position corresponding to the particle layer 13 of the anode pole piece 20, which improves the CB value of the winding battery at the corner position, thereby improving the corner lithium precipitation problem of the winding battery.
[0040] In this application embodiment, the CB value refers to the ratio of the negative electrode capacity to the positive electrode capacity per unit area. It usually needs to be greater than 1 to ensure that the amount of lithium ions that can be inserted into the negative electrode is greater than the amount of lithium ions that are extracted from the positive electrode, thus avoiding lithium deposition at the negative electrode.
[0041] Optionally, the cathode substrate 11 can be copper foil or aluminum foil, or a material substrate suitable for carrying the cathode active material layer 12.
[0042] Optionally, the anode substrate 21 can be copper foil or aluminum foil, or a material substrate suitable for carrying the first anode active material layer 22 and the second anode active material layer 23.
[0043] Understandably, the cathode active material layer 12 may include two layers, with the two cathode active material layers 12 respectively attached to the two sides of the cathode substrate 11, and the particle layer 13 embedded between the cathode substrate 11 and one of the cathode active material layers 12, and the cathode active material layer 12 covering the particle layer 13.
[0044] In one embodiment of this application, the particles in the particle layer 13 are ceramic particles, which include at least one of alumina, magnesium oxide, titanium oxide, zirconium oxide, and silicon dioxide.
[0045] In one embodiment of this application, the porosity of the particle layer 13 is (40±5)%.
[0046] In one embodiment of this application, the particle size in the particle layer 13 is 0.1 μm-5 μm.
[0047] In one embodiment of this application, the thickness of the particle layer 13 is 10% of the thickness of the cathode active material layer 12.
[0048] In one embodiment of this application, such as Figure 1 and Figure 2 As shown, the cathode electrode 10, the diaphragm 30, and the anode electrode 20 are all wound in multiple layers, from the inside out: anode electrode 20, diaphragm 30, and cathode electrode 10. The anode electrode 20 is the innermost layer. The cathode electrode 10 has N corners, where N is a positive integer and D is the sum of the thickness of the diaphragm 30 and the thickness of the anode electrode 20. The layers are arranged outward from the end of the cathode electrode 10 closest to the center along the winding direction. The length L1 of the particle layer 13 at the first corner is π*D / 2.
[0049] In one embodiment of this application, it is assumed that T is the sum of the thicknesses of the two diaphragm layers, the thickness of the anode electrode 20, and the thickness of the cathode electrode 10, and L is the length of the particle layer 13 at the Nth corner. N =π*[D+(N-1)T] / 2. Therefore, the larger the corner radius, the longer the length of particle layer 13 will be.
[0050] In an embodiment of the present application, the second anode active material layer 23 is embedded in the first anode active material layer 22, and the end face of the second anode active material layer 23 is flush with the end face of the first anode active material layer 22.
[0051] Optionally, the ratio of the gram capacity of the first anode active material layer 22 to the gram capacity of the second anode active material layer 23 is 97.7%-99.5%.
[0052] Optionally, assuming that the cathode electrode sheet 10, the separator 30 and the anode electrode sheet 20 are all wound in multiple layers, the anode electrode sheet 20 has M corners, M is a positive integer, B is the sum of the thickness of one layer of the separator and the thickness of one layer of the anode matrix 21, the first corner is sequentially arranged outward from the end of the anode electrode sheet 20 closest to the center in the winding direction, and the length S of the second anode active material layer 23 of the first corner is π*B / 2.
[0053] Optionally, assuming that P is the sum of the thickness of two layers of the separator 30, the thickness of one layer of the anode electrode sheet 20 and the thickness of one layer of the cathode electrode sheet 10, the length S of the second anode active material layer 23 of the Mth corner is π*[B+(M-1)P] / 2, and the greater the radian of the corner, the longer the length of the second anode active material layer 23. M
[0054] The present application also provides a battery comprising the wound battery cell described above, which is made of the wound battery cell provided by the present application. The wound battery cell is fully infiltrated with electrolyte, the problem of lithium precipitation at the corners is effectively improved, and the electrical stability and cycle life of the battery are improved.
[0055] The following is an embodiment description.
[0056] Embodiment 1
[0057] The wound battery cell of the present embodiment comprises a cathode electrode sheet, a separator and an anode electrode sheet which are sequentially stacked and wound with each other.
[0058] The cathode electrode sheet comprises a cathode matrix, a cathode active material layer and an alumina ceramic particle layer. The cathode active material layer is attached to at least one of the two sides of the cathode matrix, and the alumina ceramic particle layer is embedded between the cathode matrix and the cathode active material layer and located at the corner of the cathode matrix.
[0059] The porosity of the alumina ceramic particle layer is 41%, and the thickness of the alumina ceramic particle layer is 10% of the thickness of the cathode active material layer.
[0060] The length L1 of the alumina ceramic particle layer of the first corner is sequentially arranged outward from the end of the cathode electrode sheet closest to the center in the winding direction, and the length L of the particle layer of the Nth corner is π*B / 2. N = 320.28N - 229.22um.
[0061] The anode electrode sheet comprises an anode substrate, a first anode active material layer and a second anode active material layer, the first anode active material layer is attached to at least one side of the anode substrate, the second anode active material layer is arranged in one first anode active material layer, and the position of the second anode active material layer corresponds to that of the particle layer, the ratio of the gram capacity of the first anode active material layer to that of the second anode active material layer is 98.5%.
[0062] The length S of the second anode active material layer of the first corner is 15.7um, and the length S of the second anode active material layer of the Mth corner is 320.28M - 298.3um. M = 320.28M - 298.3um.
[0063] The winding cell is made into a battery.
[0064] Comparative Example 1
[0065] The comparative battery is a commercially available battery, which has the same specification as Example 1, the cathode electrode sheet of the winding cell does not have a particle layer, and the anode electrode sheet does not have a second anode active material layer which is the same as or similar to that of the present application.
[0066] The lithium precipitation of the battery of Example 1 and the battery of Comparative Example 1 is detected, and the detection results are shown in Table 1.
[0067] Table 1
[0068] Group 1000 cycle corner interface 1000 cycle cyclic thickness swell Comparative Example 1 Severe lithium precipitation 15.3％ Example 1 No lithium precipitation 8.5％
[0069] From the above test results, it can be seen that the winding cell of the present application effectively improves the corner lithium precipitation problem of the winding cell, and further improves the electrical stability of the battery.
[0070] The above description is only the preferred embodiment of the present application, and is not intended to limit the present application, any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.
Claims
1. A wound cell, characterized by: The cathode electrode sheet, the separator, and the anode electrode sheet are sequentially stacked and wound with each other. The cathode electrode sheet comprises a cathode base, a cathode active material layer attached to at least one side of the cathode base in the thickness direction, and a particle layer embedded between the cathode base and the cathode active material layer and located at the corner of the cathode base. The anode electrode sheet comprises an anode base, a first anode active material layer attached to at least one side of the anode base in the thickness direction, and a second anode active material layer provided between the anode base and the first anode active material layer and corresponding to the position of the particle layer, and the gram capacity of the second anode active material layer is greater than that of the first anode active material layer.
2. The wound cell core of claim 1, wherein: The particles in the particle layer are ceramic particles.
3. The wound cell core of claim 1, wherein: The porosity of the particle layer is (40±5) %.
4. The wound cell core of claim 1, wherein: The particle size of the particles in the particle layer is 0.1-5 μm; and / or, The thickness of the particle layer is 10% of the thickness of the cathode active material layer.
5. The wound cell according to any one of claims 1 to 4, wherein: The cathode electrode sheet, the separator, and the anode electrode sheet are wound with multiple layers, the cathode electrode sheet has N corners, N is a positive integer, D is the sum of the thickness of the separator and the thickness of the anode electrode sheet, the first corner is ranked outward from the end of the cathode electrode sheet closest to the center in the winding direction, and the length L1 of the particle layer of the first corner is π*D / 2.
6. The wound cell core of claim 5, wherein: Let T be the sum of the thickness of two layers of said separator, the thickness of one layer of said anode electrode tab and the thickness of one layer of said cathode electrode tab, the length L of said particle layer of the Nth corner N = π * [D + (N - 1)T] / 2.
7. The wound cell according to claim 1, wherein The second anode active material layer is embedded in the first anode active material layer, and the end surface of the second anode active material layer is flush with the end surface of the first anode active material layer; and / or, The ratio of the gram capacity of the first anode active material layer to the gram capacity of the second anode active material layer is 97.7-99.5 %.
8. The wound cell core of claim 1, wherein: The cathode electrode sheet, the separator, and the anode electrode sheet are wound with multiple layers, the anode electrode sheet has M corners, M is a positive integer, B is the sum of the thickness of one layer of the separator and the thickness of one layer of the anode base, the first corner is ranked outward from the end of the anode electrode sheet closest to the center in the winding direction, and the length S of the second anode active material layer of the first corner is π*B / 2.
9. The wound cell core of claim 8, wherein: Let P be the sum of the thickness of two layers of the separator, the thickness of one layer of the anode electrode sheet, and the thickness of one layer of the cathode electrode sheet, and the length S of the second anode active material layer of the Mth corner M = π * [B + (M - 1)P] / 2.
10. A battery, characterized by: The winding battery cell comprises the winding battery cell according to any one of claims 1-9.