Lithium ion battery composite current collector electrode plate
By setting the ears on the composite collector electrode sheet and controlling their position, the problems of winding instability and high electronic impedance in lithium-ion batteries are solved, and the electrical performance of the battery and the pass rate of the production process are improved.
Patent Information
- Application Number
- CN202421627459.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-10
- Publication Date
- 2025-06-13
- Estimated Expiration
- 2034-07-10
AI Technical Summary
The composite current collector electrode sheet has problems of winding instability and high electron impedance in lithium-ion batteries, resulting in difficult production and poor battery performance.
By providing electrode ears on the composite current collector electrode sheet and controlling their position at 1/5 to 4/5 of the length direction of the composite current collector, the distance between the two electrode ears is not greater than the width of the battery cell after being wound on the composite current collector electrode sheet of the lithium-ion battery.
It effectively solves the problems of difficult production of composite liquid polymer lithium-ion batteries and large internal impedance of the battery, and improves the battery's electrical performance and the pass rate of the production process.
Smart Images
Figure CN222980515U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the field of lithium-ion batteries, and particularly relates to a lithium-ion battery composite current collector electrode tab. Background Art
[0002] Normally, the tabs of the composite current collector electrode are riveted to both ends of the composite current collector, as shown in the attached figure. The main potential hazards brought by this problem are as follows: 1) The tabs are at the ends of the electrode tab. For polymer batteries, it is very difficult to control the center distance during winding, and mass production cannot be achieved; 2) The electrode impedance is large, which affects the electrical performance such as the battery rate. Figure 1 For the above problems, the existing solutions are to reduce the winding speed as much as possible, control the consistency of the center distance, or measure the length of each electrode tab so that the tabs stay at the designed positions; in terms of impedance, the main method is to increase the content of conductive agents in the electrode design or use conductive adhesives of carbon nanotubes with super high conductivity; on the other hand, the ionic conductivity is improved by changing the conductivity and solvent type of the electrolyte to reduce the impedance of the battery; the winding control and impedance improvement are carried out through the above processes and designs.
[0003] However, the above methods have problems of low winding efficiency and low qualification rate in process control, which is not conducive to the mass production of polymer lithium-ion batteries; by increasing the conductive adhesive to change the electrode conductivity, the content of active substances is reduced to a certain extent, and the energy density of the electrode is reduced; increasing the conductivity of the electrolyte and changing the solvent type will reduce the high-temperature performance of the battery under the same conditions.
[0004] Summary of the Utility Model
[0005] The purpose of the utility model is to provide a lithium-ion battery composite current collector electrode tab to solve the above technical problems.
[0006] To achieve the above purpose, the technical solution adopted by the utility model is: a lithium-ion battery composite current collector electrode tab, comprising:
[0007] A composite current collector, the composite current collector includes a first side and a second side arranged along the thickness direction of the composite current collector;
[0008] Tabs, there are two tabs, which are respectively connected to the first side and the second side, and the distance between the two tabs in the length direction of the composite current collector ≤ L, where L is the width of the battery cell formed after winding the lithium-ion battery composite current collector electrode tab.
[0009] The utility model controls the position of the tab. The distance between the two tabs in the length direction of the composite current collector is ≤L, that is, the distance between the two tabs is not greater than the width of the battery core formed after the electrode sheet of the lithium-ion battery composite current collector is wound. The normal winding of the electrode sheet can make the distance between the tabs of the winding core completely consistent with the designed position, and the inherent problem is solved by changing the method of measuring the fixed length of the electrode sheet or changing the winding efficiency.
[0010] Further, the connection position between the tab and the composite current collector is at 1 / 5 - 4 / 5 of the length direction of the composite current collector. Compared with the traditional method of setting the tabs at both ends of the composite current collector, in this application, by setting the tabs at 1 / 5 - 4 / 5 of the length direction of the composite current collector, the current on both sides of the tab flows towards the tab, shortening the current flow distance, effectively reducing the electronic impedance of the electrode, and quickly solving the problem of large internal impedance of the battery; thus solving the problems of high production difficulty of the composite current collector polymer lithium-ion battery and large internal impedance of the battery.
[0011] Further, the two tabs are arranged in a staggered manner in the length direction of the composite current collector. The staggered arrangement here means that the two tabs are not symmetrically arranged on both sides of the composite current collector, and the distance between the two tabs in the length direction of the composite current collector is greater than 0.
[0012] Further, a plurality of active material layers are arranged on the composite current collector, and a gap is left between adjacent active material layers. The tab is connected to the composite current collector at the gap. Ensure that active material layers are provided on both the left and right sides of the composite current collector, and the current generated on the active material layer converges towards the tab located at the gap.
[0013] Further, two first active material layers are arranged along the length direction of the first side surface, a first gap is left between the two first active material layers, two second active material layers are arranged along the length direction of the second side surface, and a second gap is left between the two second active material layers.
[0014] Further, the width of the gap is greater than the distance between the two tabs in the length direction of the composite current collector, and the first gap and the second gap are symmetrically arranged on both sides of the composite current collector. By symmetrically arranging the first gap and the second gap, the process flow of preparing the active material layer on the composite current collector can be simplified and it is easy to operate.
[0015] Further, the widths of the first gap and the second gap are slightly larger than the width of the tab. The first gap and the second gap are staggered on both sides of the composite current collector in the length direction of the composite current collector. The two tabs are respectively located in the first gap and the second gap. By staggering the first gap and the second gap, it is ensured that the two tabs can be staggered. Minimize the widths of the first gap and the second gap as much as possible, and make the widths of the first gap and the second gap slightly larger than the width of the tab, so as to increase the area of the active material layer and improve the battery capacitance.
[0016] Further, the composite current collector includes an insulating layer and a conductive layer located in the thickness direction of the insulating layer.
[0017] Further, the material of the insulating layer is selected from any one of PE, PET or PP.
[0018] Further, the tab and the composite current collector are connected by riveting.
[0019] The beneficial effects of the present utility model are as follows:
[0020] 1) By controlling the positions of the tabs in the present utility model, the distance between the two tabs in the length direction of the composite current collector ≤ L, that is, the distance between the two tabs is not greater than the width of the battery cell formed after the electrode tab of the lithium-ion battery composite current collector is wound. The normal winding of the electrode tab can make the distance between the tabs of the winding core completely consistent with the designed position, and solve the inherent problem by changing the method of measuring the fixed length of the electrode tab or changing the winding efficiency.
[0021] 2) In the present application, by arranging the tabs at the 1 / 5 - 4 / 5 position in the length direction of the composite current collector, the current on both sides of the tabs flows towards the tabs, shortening the current flow distance, effectively reducing the electronic impedance of the electrode, and quickly solving the problem of large internal impedance of the battery; thus solving the problems of high production difficulty of the composite current collector polymer lithium-ion battery and large internal impedance of the battery. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] The drawings constituting a part of this application are used to provide a further understanding of the present utility model. The schematic embodiments of the present utility model and their descriptions are used to explain the present utility model and do not constitute an improper limitation to the present utility model.
[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.
[0024] Figure 1 Schematic diagram of a conventional composite current collector electrode tab
[0025] Figure 2 Schematic diagram of a lithium-ion battery composite current collector electrode tab according to an embodiment of the present invention
[0026] Figure 3 is Figure 2 partial enlarged view of
[0027] Figure 4 Schematic diagram of a lithium-ion battery composite current collector electrode tab according to another embodiment of the present invention
[0028] Figure 5 Top view of a lithium-ion composite current collector electrode tab according to an embodiment of the present invention
[0029] Figure 6 Schematic diagram after battery encapsulation according to an embodiment of the present invention
[0030] Figure 7 Internal resistance value of the battery prepared in Example 1
[0031] Figure 8 Internal resistance value of the battery prepared in Comparative Example 1
[0032] In the figure: 1. Composite current collector; 11. First side; 12. Second side; 13. Insulating layer; 14. Conductive layer; 2. Tab; 3. Active material layer; 31. First active material layer; 32. Second active material layer; 4. Void; 41. First void; 42. Second void Detailed implementation manners
[0033] To make the above objects, features and advantages of the present invention more obvious and understandable, the following will describe the detailed implementation manners of the present invention in conjunction with the accompanying drawings. Many specific details are set forth in the following description in order to fully understand the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below
[0034] Referring to the attached Figures 2 to 5 As shown, a lithium-ion battery composite current collector 1 electrode tab in this embodiment includes a composite current collector 1, and the composite current collector 1 includes an insulating layer 13 and a conductive layer 14 located in the thickness direction of the insulating layer 13. The material of the insulating layer 13 is selected from any one of PE, PET or PP, and the material of the conductive layer 14 is copper metal or aluminum metal
[0035] In some embodiments, it further includes tab 2, and the tab 2 and the composite current collector 1 are connected by riveting. Specifically, the composite current collector 1 includes a first side 11 and a second side 12 arranged along the thickness direction of the composite current collector 1; there are two tabs 2, which are respectively connected to the first side 11 and the second side 12, and the distance L2 between the two tabs 2 in the length direction of the composite current collector 1 is ≤ L, as shown in the appendix Figure 6 As shown, L is the width of the battery core formed after the electrode tab of the lithium-ion battery composite current collector 1 is wound, and L2 is the distance between the mutually remote sides of the two tabs 2.
[0036] By controlling the position of the tab 2 in the present utility model, the distance L2 between the two tabs 2 in the length direction of the composite current collector 1 is ≤ L, that is, the distance between the two tabs 2 is not greater than the width L of the battery core formed after the electrode tab of the lithium-ion battery composite current collector 1 is wound. Normal winding of the electrode tab can make the distance between the tabs 2 of the wound core completely conform to the designed position, overcoming the inherent problems by measuring the fixed length of the electrode tab or changing the winding efficiency.
[0037] As shown in the appendix Figure 6 As shown, the size of L1 of the battery manufactured by the present invention can be completely determined according to the design requirements during the winding process, and it will not change due to winding tension, different winding equipment, and the number of winding turns; the conventional design will change due to factors such as winding tension, different winding equipment, and the number of winding turns, and this change is random and unpredictable, which has a great impact on the winding and packaging of polymer lithium-ion batteries. By limiting the positions of the two tabs 2, the present utility model has very important significance for improving the electrical performance and process qualification rate of polymer lithium-ion batteries with composite current collector electrode tabs.
[0038] In some embodiments, the connection position of the tab 2 and the composite current collector 1 is at 1 / 5 - 4 / 5 of the length direction of the composite current collector 1. Compared with the traditional method of arranging the tab 2 at both ends of the composite current collector 1 (as shown in the appendix Figure 1 As shown), by arranging the tab 2 at 1 / 5 - 4 / 5 of the length direction of the composite current collector 1 in the present application, the current on both the left and right sides of the tab 2 flows towards the tab 2, shortening the current flow distance, effectively reducing the electronic impedance of the electrode, and reducing the internal impedance of the battery; thus solving the problems of high production difficulty of polymer lithium-ion batteries with composite current collector 1 and large internal impedance of the battery.
[0039] In some embodiments, the two tab ears 2 are arranged with a dislocation in the length direction of the composite current collector 1. The dislocation arrangement here means that the two tab ears 2 are not symmetrically arranged on both sides of the composite current collector 1, preventing the tab ears from being arranged on both sides of the same position of the composite current collector. Since the composite current collector is relatively thin, the composite current collector may be damaged.
[0040] In some embodiments, a plurality of active material layers 3 are arranged on the composite current collector 1, and a gap 4 is left between adjacent active material layers 3. The tab ear 2 is connected to the composite current collector 1 at the gap 4. Ensure that the tab ear 2 is provided with active material layers 3 on both the left and right sides of the composite current collector 1, and the current generated on the active material layer 3 converges to the tab ear 2 located at the gap 4.
[0041] In some embodiments, see the attached Figure 2 As shown, two first active material layers 31 are arranged along the length direction of the first side surface 11, and a first gap 41 is left between the two first active material layers 31. Two second active material layers 32 are arranged along the length direction of the second side surface 12, and a second gap 42 is left between the two second active material layers 32. The width L4 of the gap 4 is greater than the distance L2 between the two tab ears 2 in the length direction of the composite current collector 1. The distance between the tab ears 2 is the distance between the mutually remote side surfaces of the two tab ears 2. The first gap 41 and the second gap 42 are symmetrically arranged on both sides of the composite current collector 1 in the length direction of the composite current collector 1. By symmetrically arranging the first gap 41 and the second gap, the process flow of preparing the active material layer 3 on the composite current collector 1 can be simplified and it is easy to operate.
[0042] In some embodiments, see the attached Figure 4 As shown, the widths of the first gap 41 and the second gap 42 are slightly larger than the width of the tab ear 2. The first gap 41 and the second gap 42 are arranged in a staggered manner on both sides of the composite current collector 1 in the length direction of the composite current collector 1. The two tab ears 2 are respectively located in the first gap 41 and the second gap 42. By arranging the first gap 41 and the second gap 42 in a dislocation manner, it is ensured that the two tab ears 2 can be arranged in a dislocation manner. Minimize the widths of the first gap 41 and the second gap 42 so that the widths of the first gap 41 and the second gap 42 are slightly larger than the width of the tab ear 2, thereby increasing the area of the active material layer 3 and improving the battery capacitance.
[0043] Example 1
[0044] Through the connection position of the pole piece and the composite current collector as shown in the attached Figure 2 As shown, a composite current collector current collector electrode pole piece is prepared, and a battery with a model of 756070 - 4500 mAh is made using this electrode pole piece. To make the measured value of the battery internal resistance more accurate, a total of 20 groups of batteries are made in parallel and numbered from 1 to 20.
[0045] Comparative Example 1
[0046] A battery with a model number of 756070 - 4500 mAh was fabricated. The components, thickness of the active material layer, materials of the composite current collector, etc. in the battery prepared in Comparative Example 1 and the battery prepared in Example 1 were the same. The main difference was the different connection positions between the tab and the composite current collector. In Comparative Example 1, the composite current collector current collector electrode tab was prepared through the connection position between the tab and the composite current collector as shown in the appendix Figure 1 and the battery with a model number of 756070 - 4500 mAh was fabricated using this electrode tab. To make the measured values of the battery internal resistance more accurate, a total of 20 groups of batteries were fabricated in parallel and numbered from 1 to 20.
[0047] Experimental Example
[0048] The internal resistances of the 20 groups of batteries prepared in Example 1 were tested, and the test results are as shown in the appendix Figure 7 ; the internal resistances of the 20 groups of batteries prepared in Comparative Example 1 were tested, and the test results are as shown in the appendix Figure 8 shown. It can be seen from the appendix Figure 7 and the appendix Figure 8 that the internal resistance of the battery prepared in Example 1 was significantly reduced, which was very helpful for the electrical performance of the polymer lithium-ion battery.
[0049] In the description of the present invention, it should be understood that the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present invention, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise specifically defined.
[0050] The above embodiments are only for illustrating the technical concept and features of the present invention, and the purpose is to enable those skilled in the art to understand the content of the present invention and implement it. It should not be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be covered within the protection scope of the present invention.
Claims
1. A lithium-ion battery composite current collector electrode plate, characterized in that: include: A composite current collector (1), the composite current collector (1) comprising a first side surface (11) and a second side surface (12) arranged along a thickness direction of the composite current collector (1); A pole lug (2), wherein two pole lugs (2) are provided and are respectively connected to the first side surface (11) and the second side surface (12), and the distance between the two pole lugs (2) in the length direction of the composite current collector (1) is ≤ L, where L is the width of a battery cell formed after the composite current collector electrode sheet of the lithium-ion battery is wound.
2. The lithium-ion battery composite current collector electrode plate according to claim 1, characterized in that: The connection position between the electrode tab (2) and the composite current collector (1) is at 1 / 5 to 4 / 5 of the length of the composite current collector (1).
3. The lithium-ion battery composite current collector electrode plate according to claim 1, characterized in that: The two electrode tabs (2) are staggered in the length direction of the composite current collector (1).
4. The lithium-ion battery composite current collector electrode plate according to claim 1, characterized in that: A plurality of active material layers (3) are arranged on the composite current collector (1), gaps (4) are left between adjacent active material layers (3), and the tabs (2) are connected to the composite current collector (1) at the gaps (4).
5. The lithium-ion battery composite current collector electrode plate according to claim 4, characterized in that: Two first active material layers (31) are arranged along the length direction of the first side surface (11), and a first gap (41) is left between the two first active material layers (31); two second active material layers (32) are arranged along the length direction of the second side surface (12), and a second gap (42) is left between the two second active material layers (32).
6. The lithium-ion battery composite current collector electrode plate according to claim 5, characterized in that: The width L4 of the gap (4) is greater than the distance L2 between the two tabs (2) in the length direction of the composite current collector, and the first gap (41) and the second gap (42) are symmetrically arranged on both sides of the composite current collector (1) in the length direction of the composite current collector (1).
7. The lithium-ion battery composite current collector electrode plate according to claim 5, characterized in that: The width of the first gap (41) and the second gap (42) is greater than the width of the electrode tab (2), and the first gap (41) and the second gap (42) are alternately arranged on both sides of the composite current collector (1) in the length direction of the composite current collector (1).
8. The lithium-ion battery composite current collector electrode plate according to claim 1, characterized in that: The composite current collector (1) comprises an insulating layer (13) and a conductive layer (14) located in the thickness direction of the insulating layer (13).
9. The lithium-ion battery composite current collector electrode plate according to claim 8, characterized in that: The material of the insulating layer (13) is selected from any one of PE, PET or PP.
10. The lithium-ion battery composite current collector electrode sheet according to any one of claims 1 to 9, characterized in that: The electrode tab (2) and the composite current collector (1) are connected by riveting.