Pole piece, compression roller for preparing pole piece, roll core structure, battery and battery module
By setting active material layers of different thicknesses on the electrodes, the problem of lithium deposition in the arc region of the wound cell was solved, improving battery performance and cycle life, and achieving efficient lithium-ion transport and stress release.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SHENZHEN HIGHPOWER TECH CO LTD
- Filing Date
- 2025-04-24
- Publication Date
- 2026-04-24
AI Technical Summary
Lithium plating is prone to occur in the arc-shaped area of the wound battery cell, which affects battery performance and lifespan.
The design incorporates variations in the thickness of the active material layers in the electrode, creating arc-shaped and straight areas. By setting the thickness ratio of the first and second active material layers to 65% to 95% and compacting them with pressure rollers, consistent density is ensured.
Without sacrificing energy density, the battery performance is improved by addressing lithium plating in the arc region and insufficient kinetics in the later stages of cycling.
Smart Images
Figure CN224164218U_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of lithium-ion battery technology, and in particular to an electrode sheet, a pressure roller for preparing the electrode sheet, a core structure, a battery, and a battery module. Background Technology
[0002] Lithium-ion batteries are a new type of chemical power source with advantages such as high energy density, high power density, and long lifespan, and are widely used in electric vehicles, mobile communications, and portable electronic devices. Winded cells are a common form of lithium-ion battery electrode assembly. Their manufacturing process involves winding the positive electrode, negative electrode, and separator together using a winding machine, with adjacent positive and negative electrode sheets separated by the separator. Winded cells offer advantages such as compact structure, low cost, and high production efficiency, but they also have the problem of lithium plating easily occurring at the corners.
[0003] Lithium plating refers to the phenomenon where, during charging of a lithium-ion battery, some lithium ions fail to intercalate into the negative electrode material, forming metallic lithium on the negative electrode surface. The positive and negative electrode sheets in the curved area of the wound cell are compressed, reducing the gap between them. This results in poor electrolyte wettability or flowability in the curved area, affecting lithium ion intercalation and leading to lithium plating. Lithium plating causes battery performance degradation and shortened cycle life. Therefore, effectively preventing lithium plating in the curved area of the wound cell has become a pressing technical problem for those skilled in the art. Utility Model Content
[0004] The purpose of this invention is to provide an electrode sheet, a pressure roller for preparing the electrode sheet, a core structure, a battery, and a battery module. The electrode sheet includes a current collector and an active material layer coated on the surface of the current collector.
[0005] The active material layer includes a first active material layer and a second active material layer, and a plurality of the first active material layers and a plurality of the second active material layers are alternately arranged along the length direction of the current collector, wherein the thickness of the first active material layer is less than the thickness of the second active material layer;
[0006] The portion of the electrode sheet with the first active material layer is used to form an arc-shaped area of the core structure, and the portion of the electrode sheet with the second active material layer is used to form a straight area of the core structure; the compaction density of the first active material layer and the second active material layer is the same;
[0007] The thickness of the first active material layer is 65% to 95% of the thickness of the second active material layer.
[0008] Optionally, the thickness of the first active material layer is 70% to 90% of the thickness of the second active material layer.
[0009] Optionally, the thickness of the first active material layer is 2 μm to 15 μm less than the thickness of the second active material layer.
[0010] Optionally, the thickness of each region of the first active material layer is uniform; or,
[0011] The thickness of each region in the second active material layer is consistent.
[0012] Optionally, the thickness of each region of the first active material layer is inconsistent.
[0013] This utility model also provides a pressure roller for preparing the electrode sheet described in any of the above claims. The roller of the pressure roller is provided with protrusions, and the length of the protrusions increases sequentially along the rotation direction of the roller. The circumference of the outer circle of the pressure roller is equal to the length of the electrode sheet. The length of the pressure roller is equal to or greater than the width of the electrode sheet.
[0014] Optionally, the outer surface of the protrusion is an arc surface, and the rotation axis of the plurality of arc surfaces is the rotation axis of the pressure roller.
[0015] This utility model also provides a wound core structure, which includes a positive electrode sheet, a negative electrode sheet, and a separator. The positive electrode sheet and / or the negative electrode sheet are the electrodes described in any of the above-mentioned embodiments.
[0016] This utility model also provides a battery, which includes the above-described core structure.
[0017] This utility model also provides a battery module, which includes the battery described above.
[0018] Compared with the prior art, the beneficial effects of this utility model are as follows:
[0019] By appropriately setting the thickness of the active material layer on the current collector, the gap between adjacent positive and negative electrode plates in the arc region is kept within a certain range. This improves the issues of lithium plating in the arc region and insufficient kinetics during later cycling processes without significantly sacrificing the energy density of the core structure.
[0020] The above and other objects, advantages and features of this utility model will become more apparent to those skilled in the art from the following detailed description of specific embodiments of this utility model in conjunction with the accompanying drawings. Attached Figure Description
[0021] The following sections will describe some specific embodiments of the present invention in a detailed manner by way of example and not limitation, with reference to the accompanying drawings. The same reference numerals in the drawings denote the same or similar parts or components. Those skilled in the art should understand that these drawings are not necessarily drawn to scale. In the drawings:
[0022] Figure 1This is a schematic diagram of the structure of an electrode sheet according to an embodiment of the present invention;
[0023] Figure 2 This is a partial schematic diagram of the core structure according to an embodiment of the present invention;
[0024] Figure 3 This is a partial schematic diagram of the core structure according to an embodiment of the present invention;
[0025] Figure 4 This is a schematic diagram of the structure of a pressure roller according to an embodiment of the present invention.
[0026] In the diagram: 100 - electrode, 110 - current collector, 121 - first active material layer, 122 - second active material layer, 130 - arc area, 140 - straight area, 200 - pressure roller, 210 - protrusion. Detailed Implementation
[0027] The following reference Figures 1 to 4 This invention describes an electrode sheet, a pressure roller for preparing the electrode sheet, a core structure, a battery, and a battery module according to embodiments of the present invention. In this description, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature, that is, include one or more of that feature. In the description of the present invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified. When a feature "includes or contains" one or more of the features it encompasses, unless otherwise specifically described, this indicates that other features are not excluded and may be further included.
[0028] In the description of this embodiment, the terms "one 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 utility model. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.
[0029] Figure 1 This is a schematic diagram of the structure of an electrode sheet according to an embodiment of the present invention. Figure 1 As shown, combined with Figures 2 to 4This invention provides an electrode sheet, a pressure roller for preparing the electrode sheet, a core structure, a battery, and a battery module. The electrode sheet 100 includes a current collector 110 and an active material layer coated on the surface of the current collector 110. The active material layer includes a first active material layer 121 and a second active material layer 122, with multiple first active material layers 121 and multiple second active material layers 122 alternately arranged along the length of the current collector 110. The thickness of the first active material layer 121 is less than the thickness of the second active material layer 122. The portion of the electrode sheet 100 with the first active material layer 121 forms an arc region 130 of the core structure, and the portion of the electrode sheet 100 with the second active material layer 122 forms a straight region 140 of the core structure. The thickness of the first active material layer 121 is 65% to 95% of the thickness of the second active material layer 122, and the compaction density of the first active material layer 121 and the second active material layer 122 is consistent.
[0030] Specifically, the electrode 100 is coated with a first active material layer 121 and a second active material layer 122 spaced apart. The first active material layer 121 and the second active material layer 122 have the same compaction density, but their thicknesses are different. The thickness of the first active material layer 121 is less than the thickness of the second active material layer 122. When preparing the core structure, the thinner first active material layer forms the arc region 130 of the core structure; the thicker second active material layer forms the straight region 140 of the core structure. The thickness of the first active material layer 121 is 65% to 95% of the thickness of the second active material layer 122, meaning that the gap between adjacent positive and negative electrode plates in the arc region 130 is neither too large nor too small.
[0031] When the compaction density is inconsistent, the area with lower compaction density is thicker, which reduces the cell thickness and reduces the energy density of the battery; the area with higher compaction density has difficulty in lithium ion insertion and extraction, which can lead to local lithium plating in the cell.
[0032] If the thickness of the first active material layer 121 is too small, the gap between adjacent positive and negative electrode plates in the arc region 130 will be too large, hindering lithium-ion transport and resulting in lithium plating in the early stages of cycling. If the thickness of the first active material layer 121 is too large, the gap between adjacent positive and negative electrode plates in the arc region 130 will not be significantly changed. Nor will it significantly increase the electrolyte storage capacity in the arc region 130, thus offering no significant improvement to lithium plating in the arc region 130. Furthermore, it does not provide significant stress relief space for the arc region 130, and therefore cannot improve the kinetic insufficiency problem that occurs in the later stages of cycling of the core structure.
[0033] The thickness of the first active material layer 121 is 65% to 95% of the thickness of the second active material layer 122. This ensures that the gap between adjacent positive and negative electrode plates in the arc region 130 remains within a suitable range, significantly increasing the electrolyte storage capacity in the arc region 130 and providing corresponding stress release space without hindering lithium-ion transport due to excessively large gaps. Therefore, the thickness of the first active material layer 121 improves the lithium plating problem in the arc region 130 and mitigates the kinetic deficiencies that occur in the core structure during later cycling stages, while avoiding a significant loss of energy density in the core structure.
[0034] In some embodiments of this invention, the thickness of the first active material layer 121 is 70% to 90% of the thickness of the second active material layer 122. That is, the thickness of the first active material layer 121 is controlled between 70% and 90% of the thickness of the second active material layer, further adjusting the gap between adjacent positive and negative electrode plates in the arc region 130, and improving lithium plating in the arc region 130 and the insufficient kinetics in the later stages of cycling.
[0035] In some embodiments of this invention, the thickness of the first active material layer 121 is 2μm to 15μm less than the thickness of the second active material layer 122. Specifically, the thickness of the first active material layer 121 is 2μm to 15μm less than the thickness of the second active material layer 122. Specifically, it can be 2μm, 4μm, 10μm, etc. In this embodiment, by controlling the specific value of the thickness difference between the first active material layer 121 and the second active material layer 122, the gap between adjacent positive and negative electrode plates in the arc region 130 can be adjusted, resulting in more precise control over the gap size.
[0036] In some embodiments of this invention, the thickness of each region of the first active material layer 121 is uniform. That is, the thickness of multiple first active material layers 121 is uniform. This simplifies processing.
[0037] In some embodiments of this invention, the thickness of each region of the first active material layer 121 is consistent, and the thickness of each region of the second active material layer 122 is consistent. Specifically, all the first active material layers 121 have a consistent thickness, and all the second active material layers 122 also have a consistent thickness. This facilitates the coating process.
[0038] In some embodiments of this invention, the thickness of the first active material layer 121 varies across different regions. Specifically, each first active material layer 121 is thinner in the middle and thicker at the edges. That is, the thickness of the first active material layer 121 gradually increases as it extends from the middle towards the two adjacent second active material layers 122. This arrangement creates a smooth transition between the first active material layer 121 and the second active material layer 122.
[0039] This utility model also provides a pressure roller 200 for preparing the electrode sheet 100 described in any of the above embodiments. The roller of the pressure roller 200 is provided with protrusions 210, and the length of the protrusions 210 increases sequentially along the rotation direction of the roller. The circumference of the outer circle of the pressure roller 200 is equal to the length of the electrode sheet 100. The length of the pressure roller 200 is equal to or greater than the width of the electrode sheet 100.
[0040] The specific working process is as follows: The lengths of each first active material layer 121 and each second active material layer 122 on the electrode 100 are preset according to the core structure. Based on the preset lengths of the first and second active material layers 121 and 122, the outer circumferential shape of the pressure roller 200 is set, ensuring that the circumference of the circumscribed circle of the pressure roller 200 is equal to the length of the electrode 100. That is, the path traveled by the pressure roller 200 in one rotation is exactly the length of the electrode 100. The roller shaft of the pressure roller 200 is fixed, and the rollers rotate around the roller shaft. During rotation, the rollers press the electrode 100, which has already been coated with active material, and compact the active material on the current collector 110, resulting in first and second active material layers 121 and 122 with consistent compaction density.
[0041] The circumference of the outer circle of the pressure roller 200 is equal to the length of the electrode 100. One rotation of the pressure roller 200 completes the compaction of the electrode 100. The length of the pressure roller 200 is equal to or greater than the width of the electrode 100, ensuring that the electrode 100 is rolled evenly across its width, thus improving the consistency of the active material layer.
[0042] It should be noted that the spacing between any two adjacent protrusions 210 is the same, so that the length of each second active material layer 122 is the same.
[0043] In some embodiments of this invention, the outer surface of the protrusion 210 is an arc surface, and the rotation axis of multiple arc surfaces is the rotation axis of the pressure roller 200. That is, the distance from each point on the outer surface of the protrusion 210 to the rotation axis of the pressure roller 200 is equal. During the coating stage, the coating thickness of the active material at corresponding positions of the first active material layer 121 is consistent, and after being rolled by the pressure roller 200, a first active material layer 121 with consistent compaction density can be obtained.
[0044] This invention also provides a wound core structure, which includes a positive electrode sheet, a negative electrode sheet, and a separator. The positive electrode sheet is the electrode sheet described in any of the above embodiments. Using the above-described electrode sheet as the positive electrode sheet can improve lithium deposition in the arc region of the wound core structure.
[0045] In some other embodiments of this invention, the core structure includes a positive electrode sheet, a negative electrode sheet, and a separator. The negative electrode sheet is the electrode sheet described in any of the above embodiments.
[0046] In some other embodiments of this invention, the core structure includes a positive electrode sheet, a negative electrode sheet, and a separator. Both the positive and negative electrode sheets are the electrode sheets described in any of the above embodiments.
[0047] This invention also provides a battery comprising the aforementioned winding structure. The battery using the aforementioned winding structure can significantly improve lithium plating in the arc region.
[0048] This utility model also provides a battery module, which includes multiple batteries as described above, and the multiple batteries are connected in series.
[0049] The battery module of this application contains multiple batteries, effectively increasing the capacity and application range of the battery module. Those skilled in the art can select an appropriate number based on the application and capacity of the battery module.
[0050] This utility model also provides a battery module, which includes multiple batteries as described above, and the multiple batteries are connected in parallel.
[0051] In this embodiment, multiple batteries are connected in parallel, which enables the battery module to achieve a higher battery capacity. Furthermore, when one battery is depleted or malfunctions, it does not affect the continued power supply of other batteries in the battery module, thereby ensuring the continuous operation of the electrical equipment.
[0052] This utility model also provides a battery module, which includes multiple batteries produced by the battery production equipment in any of the above embodiments, and the multiple batteries are connected in series.
[0053] The battery module of this application contains multiple batteries, effectively increasing the capacity and application range of the battery module. Those skilled in the art can select an appropriate number based on the application and capacity of the battery module.
[0054] In other embodiments of this utility model, the battery module includes multiple batteries produced by the battery production equipment in any of the above embodiments, and the multiple batteries are connected in parallel.
[0055] In this embodiment, multiple batteries are connected in parallel, which enables the battery module to achieve a higher battery capacity. Furthermore, when one battery is depleted or malfunctions, it does not affect the continued power supply of other batteries in the battery module, thereby ensuring the continuous operation of the electrical equipment.
[0056] This utility model also provides an electrical device, which includes the battery in any of the above embodiments.
[0057] The electrical device used in this application embodiment is not particularly limited, and can be any electrical device known in the prior art. In some embodiments, the electrical device may include, but is not limited to, electronic cigarettes, electronic vaporizers, wireless headphones, robot vacuum cleaners, drones, laptops, pen input computers, mobile computers, e-book players, portable telephones, portable fax machines, portable copiers, portable printers, over-ear stereo headphones, video recorders, LCD TVs, portable cleaners, portable CD players, mini CDs, transceivers, electronic notebooks, calculators, memory cards, portable recorders, radios, backup power supplies, motors, automobiles, motorcycles, electric bicycles, bicycles, lighting fixtures, toys, game consoles, clocks, power tools, flashlights, cameras, household large-capacity batteries, and lithium-ion capacitors, etc.
[0058] In some other embodiments of this utility model, the electrical device includes the battery module in any of the above embodiments.
[0059] In this embodiment, the battery module is designed according to the actual situation to enable the battery module to have more efficient energy transfer.
[0060] Preferred embodiments of the invention will now be described in more detail. While preferred embodiments of the invention are described below, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the invention will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.
[0061] Example 1
[0062] A wound core structure is disclosed, wherein the thickness of the first active material layer of the positive and negative electrode sheets is 60% of the thickness of the second active material layer. The battery cell is manufactured by winding, pressing, encapsulating, and forming processes involving the positive electrode sheet, negative electrode sheet, and separator.
[0063] Example 2
[0064] A wound core structure is disclosed, wherein the thickness of the first active material layer of the positive and negative electrode sheets is 65% of the thickness of the second active material layer. The battery cell is manufactured by winding, pressing, encapsulating, and forming processes involving the positive electrode sheet, negative electrode sheet, and separator.
[0065] Example 3
[0066] A wound core structure is disclosed, wherein the thickness of the first active material layer of the positive and negative electrode sheets is 70% of the thickness of the second active material layer. The battery cell is manufactured by winding, pressing, encapsulating, and forming processes involving the positive electrode sheet, negative electrode sheet, and separator.
[0067] Example 4
[0068] A wound core structure is disclosed, wherein the thickness of the first active material layer of the positive and negative electrode sheets is 75% of the thickness of the second active material layer. The battery cell is manufactured by winding, pressing, encapsulating, and forming processes involving the positive electrode sheet, negative electrode sheet, and separator.
[0069] Example 5
[0070] A wound core structure is disclosed, wherein the thickness of the first active material layer of the positive and negative electrode sheets is 80% of the thickness of the second active material layer. The battery cell is manufactured by winding, pressing, encapsulating, and forming processes involving the positive electrode sheet, negative electrode sheet, and separator.
[0071] Example 6
[0072] A wound core structure is disclosed, wherein the thickness of the first active material layer of the positive and negative electrode sheets is 85% of the thickness of the second active material layer. The battery cell is manufactured by winding, pressing, encapsulating, and forming processes involving the positive electrode sheet, negative electrode sheet, and separator.
[0073] Example 7
[0074] A wound core structure is disclosed, wherein the thickness of the first active material layer of the positive and negative electrode sheets is 90% of the thickness of the second active material layer. The battery cell is manufactured by winding, pressing, encapsulating, and forming processes involving the positive electrode sheet, negative electrode sheet, and separator.
[0075] Example 8
[0076] A wound core structure is disclosed, wherein the thickness of the first active material layer of the positive and negative electrode sheets is 95% of the thickness of the second active material layer. The battery cell is manufactured by winding, pressing, encapsulating, and forming the positive electrode sheet, negative electrode sheet, and separator.
[0077] Battery cell performance comparison:
[0078] Cyclic performance testing method: Charge the cell at 3C constant current and constant voltage to 4.5V, and stop charging at 0.05C. Discharge at 0.5C, and cycle for 20 and 500 times. Disassemble the battery to check the lithium plating in the arc area, and classify it as no lithium plating, slight lithium plating, moderate lithium plating, and severe lithium plating.
[0079] Cell performance tests were conducted on Examples 1 to 8, and the test results are shown in the table below:
[0080] Table 1 Battery performance test results
[0081]
[0082] As can be seen from the test results in Table 1, when the thickness of the first active material layer of the electrode is 65% to 95% of the thickness of the second active material layer, it can improve lithium plating in the arc region to a certain extent. The improvement effect is most obvious when the thickness of the first active material layer of the electrode is 70% to 90% of the thickness of the second active material layer.
[0083] Therefore, those skilled in the art should recognize that although many exemplary embodiments of the present invention have been shown and described in detail herein, many other variations or modifications conforming to the principles of the present invention can be directly determined or derived from the disclosure of the present invention without departing from the spirit and scope of the present invention. Therefore, the scope of the present invention should be understood and recognized as covering all such other variations or modifications.
Claims
1. An electrode, comprising a current collector and an active material layer coated on the surface of the current collector, characterized in that, The active material layer includes a first active material layer and a second active material layer. Multiple first active material layers and multiple second active material layers are alternately arranged along the length direction of the current collector. The thickness of the first active material layer is less than the thickness of the second active material layer. The portion of the electrode with the first active material layer is used to form an arc area of the core structure, and the portion of the electrode with the second active material layer is used to form a straight area of the core structure. The first active material layer and the second active material layer have the same compaction density; The thickness of the first active material layer is 65% to 95% of the thickness of the second active material layer.
2. The electrode sheet according to claim 1, characterized in that, The thickness of the first active material layer is 70% to 90% of the thickness of the second active material layer.
3. The electrode sheet according to claim 1, characterized in that, The thickness of the first active material layer is 2 μm to 15 μm less than the thickness of the second active material layer.
4. The electrode sheet according to claim 1, characterized in that, The thickness of the first active material layer is uniform in all regions; or, The thickness of each region in the second active material layer is consistent.
5. The electrode sheet according to claim 1, characterized in that, The thickness of the first active material layer varies in different regions.
6. A pressure roller for preparing the electrode sheet as described in any one of claims 1-5, characterized in that, The pressure roller has protrusions, and the length of the protrusions increases sequentially along the rotation direction of the roller. The circumference of the outer circle of the pressure roller is equal to the length of the electrode sheet. The length of the pressure roller is equal to or greater than the width of the electrode sheet.
7. The pressure roller according to claim 6, characterized in that, The outer surface of the protrusion is an arc surface, and the rotation axis of the multiple arc surfaces is the rotation axis of the pressure roller.
8. A core structure, characterized in that... include: A positive electrode, a negative electrode, and a separator, wherein the positive electrode and / or the negative electrode is the electrode as described in any one of claims 1-5.
9. A battery, characterized in that, Includes the core structure as described in claim 8.
10. A battery module, characterized in that, Includes the battery as described in claim 9.