Pole piece, battery cell and cylindrical lithium battery

Abstract

The utility model relates to a pole piece, a battery cell and a cylindrical lithium battery. The pole piece comprises a substrate, a plurality of liquid guide gaps allowing electrolyte to pass through are evenly formed in the substrate in the x direction, a first pole lug and a second pole lug are arranged on the two sides of the substrate in the y direction respectively, and the first pole lug and the second pole lug are arranged at the two ends of the liquid guide gaps respectively; and the corresponding battery cell is formed by winding a pole piece coated with slurry on one side or double sides. The device can enlarge a liquid discharging channel and increase the internal heat dissipation area of the battery, is beneficial to optimization of internal heat management of the battery, greatly avoids the problem of deformation of a battery cell structure caused by nonuniform stress distribution generated in a battery roll core due to constant winding tension, and is beneficial to acceleration of electrolyte passing and improvement of liquid discharging efficiency.

Description

Technical Field

[0001] This utility model belongs to the field of lithium battery technology, specifically relating to an electrode, a cell, and a cylindrical lithium battery. Background Technology

[0002] Based on their packaging methods and shapes, lithium batteries can be divided into three forms: prismatic, pouch, and cylindrical. Prismatic batteries have large single-cell capacity and high pack efficiency, but suffer from numerous models and poor consistency. Pouch batteries are small in size, have excellent heat dissipation, and high energy density, but are prone to bulging and are technically challenging. Compared to prismatic and pouch batteries, large cylindrical batteries have a high degree of standardization, offering significant advantages in production efficiency and consistency. Furthermore, as the size of large cylindrical batteries increases and they are adapted to higher-energy positive and negative electrode materials, their energy density will also improve significantly.

[0003] However, existing large-size cylindrical lithium batteries suffer from slow electrolyte loading, poor electrode wetting, and are prone to drying out during cycling, which seriously affects the cell's cycle life and restricts its performance. Utility Model Content

[0004] To address the aforementioned problems in the prior art, this utility model provides an electrode sheet, a battery cell, and a cylindrical lithium battery. The technical problem to be solved by this utility model is achieved through the following technical solution:

[0005] In a first aspect, the present invention provides an electrode, comprising: a substrate, wherein a plurality of liquid-conducting gaps for allowing electrolyte to pass through are uniformly formed on the substrate along the x-direction, and a first electrode tab and a second electrode tab are respectively disposed on both sides of the substrate along the y-direction, the first electrode tab and the second electrode tab being respectively disposed at both ends of the plurality of liquid-conducting gaps.

[0006] In some embodiments, each liquid guiding gap is a rectangular groove, and in the length direction of the electrode, the width of each liquid guiding gap along the x-direction is 4mm to 5mm, the length along the y-direction is 220mm to 232mm, and the depth along the z-direction is 80μm to 90μm.

[0007] In some embodiments, the interval length between two adjacent fluid guide gaps along the x-direction is 700 mm to 705 mm.

[0008] In some embodiments, the substrate has a rectangular sheet structure, and the areal density of the substrate is 0.015 g / cm³. 2 The length of the film along the x-direction is at least 3600 mm, the width of the film along the y-direction is 220 mm to 232 mm, and the depth along the z-direction is greater than 90 μm.

[0009] In some embodiments, the width of both the first tab and the second tab in the y direction is 5mm to 6mm.

[0010] Secondly, this utility model provides a battery cell, which is made by winding the electrode sheet described in the first aspect above with a single-sided slurry coating, wherein the winding gap is 4mm to 5mm.

[0011] Thirdly, this utility model provides a battery cell, which is made by winding the electrode sheets described in the first aspect above with double-sided slurry coating.

[0012] Fourthly, this utility model provides a cylindrical lithium battery, which includes: a battery casing and a cell as described in either the second or third aspect above, wherein the battery casing is fixed to the outside of the cell.

[0013] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0014] (1) To address the problems of slow electrolyte flow and poor electrode wetting in existing large-size cylindrical lithium batteries, which easily lead to electrolyte drying during cycling and severely affect cell cycle life and restrict cell performance, this utility model provides an electrode, a cell, and a cylindrical lithium battery. The electrode is provided with multiple liquid-conducting gaps that allow electrolyte to pass through. These gaps increase the electrolyte flow channels, effectively improving the electrolyte flow rate, thereby enhancing the electrolyte flow efficiency, increasing the electrode wetting humidity, and preventing electrolyte drying during cycling. This helps extend the cell cycle life and improve the performance of various components within the cell.

[0015] (2) When preparing the cell by winding the electrode sheet with single-sided coating, a winding gap is set to further increase the liquid channel and increase the heat dissipation area inside the battery. This is conducive to optimizing the internal thermal management of the battery and greatly avoids the problem of uneven stress distribution inside the battery core caused by constant winding tension, which in turn causes the cell structure to deform. It is also conducive to speeding up the passage of electrolyte and improving the liquid flow efficiency. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the electrode structure in a flat state provided by this utility model;

[0017] Figure 2 This is a schematic diagram of the battery cell structure provided by this utility model.

[0018] Figure label:

[0019] 1: Electrode; 10: Substrate; 11: Liquid conduction gap; 12: First tab; 13: Second tab. Detailed Implementation

[0020] The present invention will be further described in detail below with reference to specific embodiments, but the implementation of the present invention is not limited thereto.

[0021] The present invention will now be described in detail with reference to the accompanying drawings, including an electrode sheet, a battery cell, and a cylindrical lithium battery.

[0022] Figure 1 This is a schematic diagram of the electrode structure in a flat state provided by this utility model. For example... Figure 1 As shown, the electrode 1 includes: a substrate 10, a plurality of liquid-conducting gaps 11 that allow electrolyte to pass through are uniformly opened on the substrate 10, and a first electrode tab 12 and a second electrode tab 13 are respectively provided on both sides of the substrate 10 along the y direction, the first electrode tab 12 and the second electrode tab 13 are respectively provided at both ends of the plurality of liquid-conducting gaps 11.

[0023] Here, the substrate 10 has a rectangular sheet structure, and its areal density is 0.015 g / cm³. 2 The substrate 10 has a length of at least 3600 mm along the x-direction, a width of 220 mm to 232 mm along the y-direction, and a depth greater than 90 μm along the z-direction. Here, a plurality of electrolyte-conducting gaps 11 are uniformly arranged along the length of the substrate 10, allowing the electrolyte to pass through. A first tab 12 and a second tab 13 are provided in blank areas on both sides of the substrate 10 perpendicular to the plurality of electrolyte-conducting gaps.

[0024] Here, the width of the first tab 12 and the second tab 13 in the y direction is both 5mm to 6mm. Here, the two tabs cover both sides of the substrate 10 and partially cover the liquid-conducting gap 11.

[0025] Here, along the y-direction, a first tab 12 and a second tab 13 are provided on the substrate 10. Specifically, taking the first tab 12 as an example, firstly, the welding area between the first tab 12 and the substrate 10 is cleaned to remove oxide layers, oil, and other impurities, ensuring the welding surface is clean. Next, a suitable welding head and protective sheet are selected based on the tab material and thickness. Then, the first tab 12 is accurately placed at a predetermined position on the substrate 10 and fixed with a special clamp to ensure alignment and stability between the first tab 12 and the substrate 10 during welding. Subsequently, with the assistance of the protective sheet, pressure is applied to the welding area, using a heat-melting method to cause plastic deformation and intermolecular bonding at the contact surface between the first tab 12 and the substrate 10, forming a strong weld point. Here, both the first tab 12 and the second tab 13 are full tabs. By setting full tabs, the positive and negative electrodes of the battery can contact each other from both ends. Compared to traditional cylindrical batteries, the full tab design improves battery safety and reliability, while also facilitating battery use.

[0026] Here, each liquid-conducting gap 11 is a rectangular groove, and along the length of the substrate 10, each liquid-conducting gap 11 has a width of 4mm to 5mm in the x-direction, a length of 220mm to 232mm in the y-direction, and a depth of 80μm to 90μm in the z-direction. In one possible implementation, the interval between two adjacent liquid-conducting gaps 11 along the x-direction is 700mm to 705mm. Preferably, the interval is 702mm, and correspondingly, the number of liquid-conducting gaps 11 is 5.

[0027] Corresponding to the aforementioned electrode 1, this utility model also provides a battery cell. Figure 2 This is a schematic diagram of the battery cell structure provided by this utility model. Figure 2 As shown, the battery cell can be manufactured by winding in two ways. It should be noted that when the prepared electrode 1 is wound into a battery cell, it is necessary to first cut the electrode 1 from the center position in a direction perpendicular to the length of the electrode 1.

[0028] Specifically, the battery cell includes a first electrode and a second electrode that are bonded together. The first and second electrode are made of different materials but have the same shape, both being the shape of the aforementioned electrode 1. The first electrode serves as the negative electrode of the battery cell, and the second electrode serves as the positive electrode. A tab on the first electrode serves as the negative tab, and a tab on the second electrode serves as the positive tab. The positive and negative tabs are the two electrodes of the battery cell, responsible for the flow of current and the positive and negative terminals of the battery. A separator is provided on both sides of the positive electrode, and multiple liquid-conducting gaps or gap positions are provided on the side of the positive electrode away from the negative electrode.

[0029] In the process of preparing a battery cell using single-sided coated electrode sheets, both the positive and negative electrode sheets are coated with a coating or slurry. A certain gap is maintained during winding along the length or x-direction of electrode sheet 1, typically 4mm to 5mm. By utilizing the electrolyte channel gap and winding gap to increase the electrolyte flow path, the problem of uneven stress distribution inside the battery core caused by constant winding tension, which leads to the cell becoming increasingly tighter, can be overcome. This prevents cell structure deformation, facilitates faster electrolyte flow, improves electrolyte flow efficiency, increases internal heat dissipation area, and optimizes internal thermal management of the battery.

[0030] When fabricating battery cells using double-sided coated electrode sheets, the coating is applied to both sides of the positive electrode and both sides of the negative electrode, and the sheets are tightly wound during the winding process, utilizing only multiple liquid-conducting gaps for liquid introduction. It should be noted that when fabricating battery cells using the double-sided coating method, multiple liquid-conducting gaps may not be necessary on the positive electrode. However, using multiple liquid-conducting gaps will result in a 7.5 mA reduction in charge compared to not using them.

[0031] Corresponding to the aforementioned battery cell, this utility model also provides a cylindrical lithium battery. The cylindrical lithium battery includes: a battery casing and a battery cell prepared by winding using a single-sided or double-sided coating method, wherein the battery casing is fixed to the outside of the battery cell.

[0032] To address the problems of slow electrolyte flow and poor electrode wetting in existing large-size cylindrical lithium batteries, which easily lead to electrolyte depletion during cycling and severely affect cell cycle life and performance, this invention provides an electrode, a cell, and a cylindrical lithium battery. The electrode has multiple liquid-conducting gaps that allow electrolyte to pass through. These gaps increase the electrolyte flow channel, effectively improving the electrolyte flow rate and thus enhancing the electrolyte flow efficiency. This increases the electrode's wetting moisture, preventing electrolyte depletion during cycling, extending cell cycle life, and improving the performance of all components within the cell.

[0033] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0034] The foregoing description illustrates and describes several preferred embodiments of the present invention. However, as previously stated, it should be understood that the present invention is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in various other combinations, modifications, and environments, and can be altered within the scope of the present invention's conception through the foregoing teachings or related technical or knowledge. Any modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention should be within the protection scope of the appended claims.

Claims

1. An electrode sheet, characterized in that, include: The substrate (10) has a plurality of liquid-conducting gaps (11) uniformly formed on its surface along the x-direction to allow electrolyte to pass through, and a first tab (12) and a second tab (13) are respectively provided on both sides of the substrate (10) along the y-direction. The first tab (12) and the second tab (13) are respectively provided at both ends of the plurality of liquid-conducting gaps (11).

2. The electrode sheet according to claim 1, characterized in that, Each liquid guiding gap (11) is a rectangular groove, and the width of each liquid guiding gap (11) along the x direction is 4mm to 5mm, the length along the y direction is 220mm to 232mm, and the depth along the z direction is 80μm to 90μm.

3. The electrode sheet according to claim 1, characterized in that, Along the x-direction, the interval length between two adjacent liquid guiding gaps (11) is 700mm to 705mm.

4. The electrode sheet according to claim 1, characterized in that, The substrate (10) has a rectangular sheet structure and an areal density of 0.015 g / cm³. 2 The length of the film along the x-direction is at least 3600 mm, the width of the film along the y-direction is 220 mm to 232 mm, and the depth along the z-direction is greater than 90 μm.

5. The electrode sheet according to claim 1, characterized in that, The width of the first electrode tab (12) and the second electrode tab (13) in the y direction is 5mm to 6mm.

6. A battery cell, characterized in that, The battery cell is manufactured by winding an electrode sheet according to any one of claims 1 to 5 with a single-sided slurry coating, wherein the winding gap is 4 mm to 5 mm.

7. A battery cell, characterized in that, The battery cell is manufactured by winding the electrode sheet according to any one of claims 1 to 5 with double-sided slurry coating.

8. A cylindrical lithium battery, characterized in that, The cylindrical lithium battery includes: a battery casing and a cell as described in any one of claims 6 or 7, wherein the battery casing is fixed to the outside of the cell.

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