Battery cell, lithium ion battery and power utilization device
By setting a porous filling layer in the cell winding structure, the problem of insufficient liquid retention in the cell is solved, the cycle performance and safety of the cell are improved, and the liquid retention is effectively increased.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- ZHEJIANG LIWINON ENERGY TECHNOLOGY CO LTD
- Filing Date
- 2025-04-08
- Publication Date
- 2026-05-15
AI Technical Summary
Insufficient electrolyte retention in battery cells leads to lithium plating and safety hazards during cycling, and existing technologies are unable to effectively improve the electrolyte retention of battery cells.
In the winding structure of the battery cell, a porous filling layer is provided at the portion of the first and second diaphragms that extends beyond the starting ends of the anode and cathode electrodes. The filling layer adsorbs electrolyte, thereby increasing the electrolyte retention of the battery cell.
By setting a porous filling layer, the liquid retention capacity of the cell is increased, improving the cell's cycle performance and safety, and avoiding problems such as lithium plating and sudden capacity drop.
Smart Images
Figure CN224248669U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of battery technology, specifically to a battery cell, a lithium-ion battery, and an electrical device. Background Technology
[0002] Cell electrolyte retention refers to the volume of liquid electrolyte inside the cell, and it is one of the key factors necessary for the normal operation of the battery. If the electrolyte retention is insufficient, the cell is prone to lithium plating or a sudden drop in capacity during cycling, and may even cause safety problems such as fire or explosion.
[0003] Therefore, it is urgent to improve the cell structure to increase the electrolyte retention of the cell. Utility Model Content
[0004] The purpose of this application is to overcome the shortcomings of the prior art and provide a battery cell, a lithium-ion battery, and an electrical device. This application defines a first pre-wound section as the portion of the first separator that extends beyond the winding start ends of the anode and cathode electrodes, and a second pre-wound section as the portion of the second separator that extends beyond the winding start ends of the anode and cathode electrodes. At least one side of the first pre-wound section and / or at least one side of the second pre-wound section is provided with a filling layer with a porous structure. The filling layer adsorbs electrolyte, thereby increasing the electrolyte retention of the battery cell.
[0005] To achieve the above objectives, in a first aspect of this application, this application provides a battery cell, including a first separator, an anode plate, a second separator, and a cathode plate, wherein the first separator, the anode plate, the second separator, and the cathode plate are sequentially stacked and wound into a wound structure.
[0006] In the winding direction of the winding structure, both the first diaphragm and the second diaphragm extend beyond the winding start end of the anode electrode and the winding start end of the cathode electrode. The portion of the first diaphragm extending beyond the winding start end of the anode electrode and the winding start end of the cathode electrode is a first pre-wound section, and the portion of the second diaphragm extending beyond the winding start end of the anode electrode and the winding start end of the cathode electrode is a second pre-wound section.
[0007] A filling layer is provided on at least one side of the first pre-wound segment and / or at least one side of the second pre-wound segment, the filling layer having a porous structure.
[0008] As an embodiment of this application, the anode electrode includes a single-sided region, one side of which is provided with an anode active material layer, and the other side is an exposed current collector. The thickness of the single-sided region is H; the thickness of the filling layer is h1; the sum of the thickness of the first pre-wound segment and the thickness of the second pre-wound segment is h2; the number of filling layers is n, where n is 1 to 8, and h1 = (H - h2) / n.
[0009] As an embodiment of this application, in the winding direction of the first pre-wound segment, the two end edges of the first pre-wound segment are respectively flush with the corresponding two end edges of the filling layer.
[0010] As an embodiment of this application, in the winding direction of the second pre-wound segment, the two end edges of the second pre-wound segment are respectively flush with the corresponding two end edges of the filling layer.
[0011] As an embodiment of this application, the number of turns of the first pre-wound segment and the number of turns of the second pre-wound segment are each independently 0.5 to 1 turn.
[0012] As an embodiment of this application, the filling layer is a mesh-structured adhesive layer.
[0013] As an embodiment of this application, the other sections of the first diaphragm, excluding the first pre-wound section, are the first winding section. At least one side surface of the first winding section is provided with a first coating layer, and the thickness of the first coating layer is the same as the thickness of the filler layer.
[0014] As an embodiment of this application, the other sections of the second diaphragm, excluding the second pre-wound section, are the second winding section. At least one side surface of the second winding section is provided with a second coating layer, and the thickness of the second coating layer is the same as the thickness of the filler layer.
[0015] In a second aspect of this application, a lithium-ion battery is provided, comprising the cell as described in the first aspect.
[0016] In a third aspect of this application, an electrical device is provided, including a battery as described in the second aspect. Attached Figure Description
[0017] Figure 1 This is a schematic diagram of the battery cell structure provided in this application;
[0018] Figure 2 A partial cross-sectional view of the first diaphragm provided for this application;
[0019] Figure 3 A partial cross-sectional view of the second diaphragm provided for this application.
[0020] In the figure, 1 is the first diaphragm, 11 is the first pre-winding section, 12 is the first winding section, 2 is the second diaphragm, 21 is the second pre-winding section, 22 is the second winding section, 3 is the anode electrode, 4 is the cathode electrode, 5 is the filler layer, 6 is the first coating layer, and 7 is the second coating layer. Detailed Implementation
[0021] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0022] In this application, the technical features described in an open-ended manner include both closed technical solutions consisting of the listed features and open technical solutions that include the listed features.
[0023] In this application, the use of "first" and "second" is for the purpose of distinguishing technical features only and should not be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated or the order of the technical features indicated.
[0024] In this application, unless otherwise expressly defined, terms such as "setup," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this application in conjunction with the specific content of the technical solution.
[0025] In this application, the terms "an embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this application, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.
[0026] Please see Figures 1-3 In a first aspect of this application, this application provides a battery cell, including a first separator 1, an anode plate 3, a second separator 2 and a cathode plate 4, wherein the first separator 1, the anode plate 3, the second separator 2 and the cathode plate 4 are stacked in sequence and wound into a wound structure.
[0027] In the winding direction of the winding structure, both the first diaphragm 1 and the second diaphragm 2 extend beyond the winding start end of the anode electrode 3 and the winding start end of the cathode electrode 4. The portion of the first diaphragm 1 that extends beyond the winding start end of the anode electrode 3 and the winding start end of the cathode electrode 4 is the first pre-wound section 11, and the portion of the second diaphragm 2 that extends beyond the winding start end of the anode electrode 3 and the winding start end of the cathode electrode 4 is the second pre-wound section 21.
[0028] A filling layer 5 is provided on at least one side of the first pre-wound section 11 and / or at least one side of the second pre-wound section 21, the filling layer 5 having a porous structure.
[0029] Compared with the prior art, this application uses the portion of the first diaphragm 1 that extends beyond the winding start end of the anode electrode 3 and the winding start end of the cathode electrode 4 as the first pre-wound section 11, and the portion of the second diaphragm 2 that extends beyond the winding start end of the anode electrode 3 and the winding start end of the cathode electrode 4 as the second pre-wound section 21. At least one side of the first pre-wound section 11 and / or at least one side of the second pre-wound section 21 is provided with a filling layer 5 having a porous structure, and the electrolyte is adsorbed by the filling layer 5 to increase the electrolyte retention of the battery cell.
[0030] In one embodiment, the anode electrode 3 includes a single-sided region. One surface of the single-sided region is provided with an anode active material layer, and the other surface is an exposed current collector. The thickness of the single-sided region is H. The thickness of the filler layer 5 is h1. The sum of the thicknesses of the first pre-wound section 11 and the second pre-wound section 21 is h2. The number of filler layers 5 is n, where n is 1 to 8, and h1 = (H - h2) / n. The thickness of the filler layer 5 satisfies the above conditions, balancing the thickness of the single-sided region of the anode electrode 3 at corners, and also effectively increasing the electrolyte retention of the cell, thereby improving the cell's cycle performance.
[0031] For example, n can be 1, 2, 3, 4, 5, 6, 7, 8, or a range consisting of any two sets of values.
[0032] In one embodiment, in the winding direction of the first pre-wound segment 11, the two end edges of the first pre-wound segment 11 are flush with the corresponding two end edges of the filler layer 5.
[0033] In one embodiment, in the winding direction of the second pre-wound segment 21, the two end edges of the second pre-wound segment 21 are flush with the corresponding two end edges of the filler layer 5.
[0034] In one embodiment, along the axial direction of the winding structure, the two ends of the first pre-wound segment 11 are flush with the corresponding two ends of the filling layer 5.
[0035] In one embodiment, in the winding direction of the second pre-wound segment 21, the two end edges of the second pre-wound segment 21 are flush with the corresponding two end edges of the filler layer 5.
[0036] For example, with the axial direction of the winding structure as the vertical direction, the upper edge of the first pre-wound section 11 is flush with the upper edge of the filler layer 5, and the lower edge of the first pre-wound section 11 is flush with the lower edge of the filler layer 5; similarly, the upper edge of the second pre-wound section 21 is flush with the upper edge of the filler layer 5, and the lower edge of the second pre-wound section 21 is flush with the lower edge of the filler layer 5.
[0037] In one embodiment, the number of turns of the first pre-winding section 11 and the number of turns of the second pre-winding section 21 are each independently 0.5 to 1 turn.
[0038] In one embodiment, the filler layer 5 is a mesh-structured adhesive layer.
[0039] The material of the mesh structure adhesive layer can be sponge adhesive or porous foam adhesive.
[0040] During cycling, the cell expands, generating expansion stress, which compresses the filler layer 5 and releases the electrolyte. At the same time, the thickness of the filler layer 5 becomes smaller after being compressed, thereby reducing the impact of the filler layer 5 thickness on the cell's energy density.
[0041] In one embodiment, the other sections of the first diaphragm 1, excluding the first pre-wound section 11, are the first winding section 12. At least one side surface of the first winding section 12 is provided with a first coating layer 6, and the thickness of the first coating layer 6 is the same as the thickness of the filler layer 5.
[0042] Specifically, the first coating layer 6 comprises inorganic particles and a binder. The inorganic particles in the first coating layer 6 account for 95–99.5% of the total mass, and the binder accounts for 0.5–5% of the total mass. The inorganic particles in the first coating layer 6 may include at least one of alumina, silica, zirconium oxide, titanium dioxide, and boehmite. The binder in the first coating layer 6 may include at least one of polyvinylidene fluoride, polyvinylidene fluoride, styrene-butadiene rubber, polyacrylate, and sodium carboxymethyl cellulose.
[0043] In one embodiment, the other sections of the second diaphragm 2, excluding the second pre-wound section 21, are the second winding section 22. At least one side surface of the second winding section 22 is provided with a second coating layer 7, and the thickness of the second coating layer 7 is the same as the thickness of the filler layer 5.
[0044] Specifically, the material of the second coating layer 7 includes inorganic particles and a binder. The mass percentage of the inorganic particles in the second coating layer 7 is 95-99.5%, and the mass percentage of the binder in the second coating layer 7 is 0.5-5%. The inorganic particles in the second coating layer 7 may include at least one of alumina, silicon dioxide, zirconium oxide, titanium dioxide, and boehmite. The binder in the second coating layer 7 may include at least one of polyvinylidene fluoride, polyvinylidene fluoride, styrene-butadiene rubber, polyacrylate, and sodium carboxymethyl cellulose.
[0045] In this application, the material of the first diaphragm 1 can be an existing conventional diaphragm.
[0046] In this application, the material of the second diaphragm 2 can be an existing conventional diaphragm.
[0047] In a second aspect of this application, embodiments of this application also provide a lithium-ion battery, including the cell described in the first aspect.
[0048] It should be noted that in this application, the anode plate 3 is connected to the negative electrode tab of the battery, and the cathode plate 4 is connected to the positive electrode tab of the battery.
[0049] In a third aspect of this application, an electrical device is provided, including a battery as described in the second aspect.
[0050] The inventors conducted extensive research experiments during the research process, including designing and fabricating different battery cells and lithium-ion batteries, and testing battery performance. Some of the experimental examples and test results are listed below to illustrate this application:
[0051] Example 1
[0052] Please see Figures 1-3 A lithium-ion battery includes a cell, comprising a first separator 1, an anode electrode 3, a second separator 2, and a cathode electrode 4. The first separator 1, the anode electrode 3, the second separator 2, and the cathode electrode 4 are sequentially stacked and wound into a wound structure. In the winding direction of the wound structure, both the first separator 1 and the second separator 2 extend beyond the winding start ends of the anode electrode 3 and the cathode electrode 4. The portion of the first separator 1 extending beyond the winding start ends of the anode electrode 3 and the cathode electrode 4 is a first pre-wound section 11, and the portion of the second separator 2 extending beyond the winding start ends of the anode electrode 3 and the cathode electrode 4 is a second pre-wound section 21. A filling layer 5 is provided on both sides of the first pre-wound section 11 in its thickness direction and on both sides of the second pre-wound section 21 in its thickness direction. The filling layer 5 is a sponge adhesive layer with a mesh structure.
[0053] In the winding direction of the first pre-wound section 11, the two ends of the first pre-wound section 11 are flush with the corresponding two ends of the filler layer 5; in the winding direction of the second pre-wound section 21, the two ends of the second pre-wound section 21 are flush with the corresponding two ends of the filler layer 5; in the axial direction of the winding structure, the two ends of the first pre-wound section 11 are flush with the corresponding two ends of the filler layer 5, and the two ends of the second pre-wound section 21 are flush with the corresponding two ends of the filler layer 5.
[0054] The anode electrode 3 includes a single-sided region. One side of the single-sided region is provided with an anode active material layer, and the other side is an exposed current collector. The thickness of the single-sided region is H. The thickness of the filling layer 5 is h1. The sum of the thickness of the first pre-wound section 11 and the thickness of the second pre-wound section 21 is h2. The number of filling layers 5 is n, where n is 8, and h1 = (H - h2) / 8.
[0055] The number of turns in the first pre-winding section 11 and the number of turns in the second pre-winding section 21 are both 0.5 turns.
[0056] The first diaphragm 1, excluding the first pre-wound section 11, is a first winding section 12. At least one side surface of the first winding section 12 is provided with a first coating layer 6, the thickness of which is the same as the thickness of the filler layer 5. The second diaphragm 2, excluding the second pre-wound section 21, is a second winding section 22. At least one side surface of the second winding section 22 is provided with a second coating layer 7, the thickness of which is the same as the thickness of the filler layer 5.
[0057] The materials of the first coating layer 6 and the second coating layer 7 are both composed of the following components by mass percentage: 99% aluminum oxide and 1% polyvinylidene fluoride.
[0058] Both the first diaphragm 1 and the second diaphragm 2 are PP / PE / PP composite diaphragms (Celgard 2325).
[0059] During assembly, the first separator 1, the anode plate 3, the second separator 2, and the cathode plate 4 are stacked in sequence and wound in the same direction to form a battery cell; then, aluminum-plastic film is used for encapsulation, electrolyte is injected, and after vacuum encapsulation, formation, and shaping, a lithium-ion battery is obtained.
[0060] Example 2
[0061] The difference between this embodiment and embodiment 1 is that, in this embodiment, the first pre-wound segment 11 and the second pre-wound segment 21 are both provided with a filling layer 5 on one side surface of their thickness direction, n is 4, and h1 = (H-h2) / 4; the first pre-wound segment 11 is provided with a first coating layer 6 on the other side surface of its thickness direction, and the second pre-wound segment 21 is provided with a second coating layer 7 on one side surface of its thickness direction.
[0062] Example 3
[0063] The difference between this embodiment and embodiment 1 is that, in this embodiment, the first pre-wound segment 11 has a filling layer 5 on one side surface in the thickness direction, n is 2, and h1 = (H-h2) / 2; the first pre-wound segment 11 has a first coating layer 6 on the other side surface in the thickness direction, and the second pre-wound segment 21 has a second coating layer 7 on both sides surface in the thickness direction.
[0064] Comparative Example 1
[0065] The difference between this comparative example and Example 1 is that, in this comparative example, the first pre-wound segment 11 has a first coating layer 6 on both sides of its thickness direction, and the second pre-wound segment 21 has a second coating layer 7 on both sides of its thickness direction.
[0066] Performance testing
[0067] The performance of the lithium-ion batteries in the above embodiments and comparative examples was tested using the following methods:
[0068] (1) Electrolyte retention capacity of the battery cell: Weigh the battery cell when injecting electrolyte and mark it as A1; when sealing for the second time, adjust the battery cell to a state where there is no free electrolyte on the surface and weigh it and mark it as A2; at the same time, weigh the battery cell air bag removed during the second sealing for A3. Use the calculation formula: Electrolyte retention capacity = A1 - A2 - A3 to calculate the electrolyte retention capacity.
[0069] (2) Cyclic performance: The cycle performance of the battery cell was tested under a 25℃ incubator. The charge and discharge modes of the battery cell were as follows:
[0070] Charging steps:
[0071] 1. Charge at a constant current of 1.5C to 50% SOC, with a cutoff voltage of 4.53V;
[0072] 2. Charge at a constant current and constant voltage of 0.9C to 4.53V, with a cutoff rate of 0.05C;
[0073] Discharge steps:
[0074] Discharged at a constant current of 0.2C with a cutoff voltage of 3.0V.
[0075] Using the above charge-discharge method, cycle tests were conducted, and the cell capacity data was observed to see if there was a sudden drop in cell capacity due to lithium plating, in order to evaluate the impact of cell liquid retention on cycle performance.
[0076] The test results are shown in Table 1 below.
[0077] Table 1
[0078]
[0079]
[0080] The embodiments of this application have been described in detail above with reference to the accompanying drawings. However, this application is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of this application. Furthermore, unless otherwise specified, the embodiments and features described in the embodiments of this application can be combined with each other.
Claims
1. A battery cell, characterized in that, It includes a first diaphragm, an anode plate, a second diaphragm, and a cathode plate, wherein the first diaphragm, the anode plate, the second diaphragm, and the cathode plate are stacked in sequence and wound into a wound structure; In the winding direction of the winding structure, both the first diaphragm and the second diaphragm extend beyond the winding start end of the anode electrode and the winding start end of the cathode electrode. The portion of the first diaphragm extending beyond the winding start end of the anode electrode and the winding start end of the cathode electrode is a first pre-wound section, and the portion of the second diaphragm extending beyond the winding start end of the anode electrode and the winding start end of the cathode electrode is a second pre-wound section. A filling layer is provided on at least one side of the first pre-wound segment and / or at least one side of the second pre-wound segment, the filling layer having a porous structure.
2. The battery cell as described in claim 1, characterized in that, The anode electrode has a single-sided area, one side of which is provided with an anode active material layer and the other side is an exposed current collector. The thickness of the single-sided area is H. The thickness of the filling layer is h1. The sum of the thickness of the first pre-wound section and the thickness of the second pre-wound section is h2. The number of filling layers is n, where n is 1 to 8, and h1 = (H - h2) / n.
3. The battery cell as described in claim 1 or 2, characterized in that, In the winding direction of the first pre-wound segment, the two ends of the first pre-wound segment are flush with the corresponding two ends of the filler layer.
4. The battery cell as described in claim 1 or 2, characterized in that, In the winding direction of the second pre-wound segment, the two ends of the second pre-wound segment are flush with the corresponding two ends of the filler layer.
5. The battery cell as described in claim 1 or 2, characterized in that, The number of turns in the first pre-winding section and the number of turns in the second pre-winding section are each independently 0.5 to 1 turn.
6. The battery cell as described in claim 1, characterized in that, The filler layer is a mesh-structured adhesive layer.
7. The battery cell as described in claim 1, characterized in that, The first diaphragm, excluding the first pre-wound section, is a first winding section. At least one side surface of the first winding section is provided with a first coating layer, the thickness of which is the same as the thickness of the filler layer.
8. The battery cell as described in claim 1, characterized in that, The other sections of the second diaphragm, excluding the second pre-wound section, are the second winding section. At least one side surface of the second winding section is provided with a second coating layer, the thickness of which is the same as the thickness of the filler layer.
9. A lithium-ion battery, characterized in that, Includes the battery cell as described in any one of claims 1 to 8.
10. An electrical device, characterized in that, Includes the battery as described in claim 9.