Novel battery pole piece, battery cell and lithium ion battery
By adding a hydrogel layer in the thinning area of the pole sheet body of the lithium-ion battery, the problems of thinning the head of the battery cell and lithium excretion are solved, the flatness of the battery cell is improved, and the consumption of electrolyte is alleviated, which significantly improves lithium Performance of ion batteries.
Patent Information
- Application Number
- CN202323663457.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2023-12-29
- Publication Date
- 2025-02-14
- Estimated Expiration
- 2033-12-29
AI Technical Summary
During the high-speed charging process of existing lithium-ion batteries, thinning of the anode sheet leads to thinning of the battery cell head, affecting the flatness of the battery cell, easily causing lithium extraction and affecting battery performance.
The hydrogel layer is added in the thinned area of the pole sheet body. Using the free deformation characteristics of the hydrogel, the gaps in the head of the battery are filled with the hydrogel layer when wound into the battery cell to improve the flatness of the battery cell.
By adding the hydrogel layer, the flatness of the battery cell is maximized, the lithium excretion on the head of the battery cell is improved, and the problem of electrolyte consumption is alleviated during the circulation of the lithium-ion battery.
Smart Images
Figure CN222483395U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of lithium ion batteries, and in particular to a novel battery pole piece, a battery core and a lithium ion battery. Background Art
[0002] Lithium-ion batteries are widely used in electronic equipment, electric vehicles and other fields due to their advantages such as high weight, high specific power, high voltage platform, low self-discharge, long cycle life, no memory effect and good safety. With the update and iteration of 3C portable products such as smart phones, watches and tablets, the market demand has put forward higher requirements for lithium-ion batteries, such as higher energy density, faster charging speed, excellent rate discharge capability, charge and discharge temperature rise, etc.
[0003] Among them, for lithium-ion batteries with high-rate charging requirements, the anode sheet is thinned on the side near the ear, which causes the head of the battery cell to be thin, resulting in poor overall flatness of the battery cell, which can easily cause lithium deposition on the head of the battery cell and affect the performance of the lithium-ion battery. Utility Model Content
[0004] In view of the deficiencies in the prior art, the utility model provides a novel battery pole piece, a battery core and a lithium-ion battery.
[0005] The utility model discloses a novel battery pole piece, comprising a pole piece body and a hydrogel layer. The hydrogel layer is coated on the active material layer of the pole piece body along the length direction of the pole piece body, and the hydrogel layer is located in the thinning area of the pole piece body.
[0006] According to one embodiment of the present invention, the coating length L of the hydrogel layer is 水凝胶层 Shorter than the coating length L of the active material layer 活性物质层 3~5mm, coating width W of hydrogel layer 水凝胶层 The coating thickness of the hydrogel layer is 1-4 mm. 水凝胶层 It is 0.3~0.7mm.
[0007] According to one embodiment of the present invention, the hydrogel layer is coated horizontally and centrally on the active substance layer.
[0008] According to one embodiment of the present invention, the hydrogel layer has a three-dimensional network structure, the cross-linking degree of the hydrogel layer is 10 to 90%, and the viscosity of the hydrogel layer is 2500 to 9000 Pa·s.
[0009] According to one embodiment of the present invention, the pole piece body is an anode piece.
[0010] According to one embodiment of the present invention, the pole piece body includes a current collector, a pole ear and an active material layer. The pole ear is arranged on one side of the current collector, and the active material layer is coated on one side or both sides of the current collector.
[0011] According to one embodiment of the present invention, there are multiple pole tabs, and the multiple pole tabs are arranged at intervals along the length direction of the current collector.
[0012] According to one embodiment of the utility model, the pole piece body further includes a primer layer, the primer layer is coated on one side or both sides of the current collector, and the active material layer is coated on the primer layer.
[0013] The utility model discloses a battery cell, characterized in that it includes the novel battery pole piece as described above, and also includes a conventional battery pole piece and a diaphragm, the pole piece body has an opposite polarity to the conventional battery pole piece, and the conventional battery pole piece, the diaphragm, the novel battery pole piece and the diaphragm are stacked in sequence and then wound into a battery cell.
[0014] The utility model discloses a lithium ion battery, comprising the above-mentioned battery core, wherein the battery core is packaged in a shell, and an electrolyte is injected into the shell.
[0015] Compared with the prior art, the novel battery pole piece, battery cell and lithium-ion battery of the utility model have the following advantages:
[0016] The novel battery pole piece of the utility model adds a hydrogel layer in the thinned area of the pole piece body, utilizes the free deformation property of the hydrogel, and fills the gap at the head of the battery cell through the hydrogel layer when winding into a battery cell, which can maximize the flatness of the battery cell and thus improve the phenomenon of lithium deposition at the head of the battery cell.
[0017] In addition, after the new battery electrode of the utility model is made into a lithium-ion battery, its hydrogel layer will absorb part of the electrolyte, which can not only improve the lithium deposition at the head of the battery cell, but also improve the lithium deposition at the corners of the battery cell; at the same time, during the circulation process of the lithium-ion battery, the battery electrode expands and squeezes the hydrogel layer, so that the electrolyte absorbed by the hydrogel layer is released, effectively alleviating the consumption of electrolyte at the head of the battery cell caused by circulation. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:
[0019] Figure 1 It is a structural plan view of a novel battery electrode sheet in an embodiment;
[0020] Figure 2 It is a structural side view of a novel battery electrode in an embodiment.
[0021] Description of reference numerals:
[0022] 1. Pole body; 11. Current collector; 12. Pole ear; 13. Bottom coating; 14. Active material layer; 2. Hydrogel layer. DETAILED DESCRIPTION
[0023] The following will disclose multiple embodiments of the present invention with diagrams. For the purpose of clear description, many practical details will be described together in the following description. However, it should be understood that these practical details should not be used to limit the present invention. In other words, in some embodiments of the present invention, these practical details are not necessary. In addition, for the purpose of simplifying the diagram, some conventional structures and components will be depicted in a simple schematic manner in the diagram.
[0024] In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the fact that ordinary technicians in the field can implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present utility model.
[0025] Embodiment 1
[0026] This embodiment provides a new type of battery pole piece, which is used to make a battery cell. Figure 1 The novel battery pole piece includes a pole piece body 1 and a hydrogel layer 2, and the hydrogel layer 2 is coated on the pole piece body 1. By adding the hydrogel layer 2 in the thinned area of the pole piece body 1 and utilizing the free deformation characteristics of the hydrogel, the gap at the head of the battery cell is filled with the hydrogel layer 2 when the battery cell is wound into a battery cell, which can maximize the flatness of the battery cell and improve the phenomenon of lithium deposition at the head of the battery cell.
[0027] It should be noted that the length directions described below all refer to the X-axis direction in the figures, the width directions all refer to the Y-axis direction in the figures, and the thickness directions all refer to the Z-axis direction in the figures.
[0028] See also Figure 1 and Figure 2 The pole piece body 1 includes a current collector 11, a pole ear 12, a bottom coating 13 and an active material layer 14. The pole ear 12 is welded on one side of the current collector 11 along the length direction. The bottom coating 13 is coated on one or both sides of the current collector 11. The active material layer 14 is coated on the surface of the bottom coating 13 on one or both sides.
[0029] In this embodiment, the pole piece body 1 is an anode piece. Accordingly, the current collector 11 is made of copper foil, the pole tab 12 is made of nickel sheet, and the active material layer 14 is made of graphite.
[0030] In this embodiment, there are multiple pole tabs 12, and the multiple pole tabs 12 are spaced apart along the length direction of the current collector 11. In addition, a primer layer 13 is coated on one side surface of the current collector 11, and an active material layer 14 is coated on the surface of the primer layer 13. The primer layer 13 covers a portion of the current collector 11, and the active material layer 14 covers a portion of the primer layer 13.
[0031] Review Figure 1 The hydrogel layer 2 is coated on the active material layer 14 along the length direction of the pole piece body 1, and the hydrogel layer 2 is located on the thinned area of the pole piece body 1. It should be noted that the thinned area of the pole piece body 1 refers to the area of the pole piece body 1 corresponding to the head of the battery cell, which is located on the side of the pole piece body 1 close to the pole ear 12, that is, the area A in the figure.
[0032] In this embodiment, the coating length L of the hydrogel layer 2 is 水凝胶层 shorter than the coating length L of the active material layer 14 活性物质层 3~5mm, coating width W of hydrogel layer 2 水凝胶层 The coating thickness H of the hydrogel layer 2 is 1 to 4 mm. 水凝胶层 It is 0.3~0.7mm.
[0033] Furthermore, the hydrogel layer 2 is horizontally and centrally coated on the active material layer 14, that is, the distance d between the end of one side of the hydrogel layer 2 and the end of the adjacent active material layer 14 is 1.5 to 2.5 mm. In addition, since the width of the thinning area of the electrode body 1 is controlled within 5 mm, the coating width W of the hydrogel layer 2 is 水凝胶层 The preferred value of is 4 mm, which is conducive to the diffusion and filling of the space by the hydrogel layer 2 after being compressed.
[0034] In this embodiment, the hydrogel layer 2 has a three-dimensional network structure, the cross-linking degree of the hydrogel layer 2 is 10-90%, and the viscosity of the hydrogel layer 2 is 2500-9000 Pa·s.
[0035] Embodiment 2
[0036] This embodiment provides a battery cell for making a lithium-ion battery. The battery cell includes the novel battery pole piece described in the first embodiment, and also includes a conventional battery pole piece and a diaphragm, wherein the conventional battery pole piece, the diaphragm, the novel battery pole piece and the diaphragm are stacked in sequence and then wound into a battery cell. Among them, the pole piece body has the opposite polarity to the conventional battery pole piece. Since the pole piece body is an anode piece, the conventional battery pole piece is a cathode piece.
[0037] During the process of winding to form a battery cell, the hydrogel layer is deformed under pressure, fully filling the gap at the head of the battery cell and maximizing the flatness of the battery cell.
[0038] Embodiment 3
[0039] This embodiment provides a lithium-ion battery, which includes the battery cell described in the second embodiment, the battery cell is packaged in a shell, and the shell is injected with electrolyte.
[0040] After being made into a lithium-ion battery, the hydrogel layer of the new battery electrode will absorb part of the electrolyte, which can not only improve the lithium deposition at the head of the battery cell, but also improve the lithium deposition at the corners of the battery cell; at the same time, during the circulation process of the lithium-ion battery, the battery electrode expands and squeezes the hydrogel layer, releasing the electrolyte absorbed by the hydrogel layer, effectively alleviating the consumption of electrolyte at the head of the battery cell caused by circulation.
[0041] In order to further illustrate the impact of the present application on lithium-ion batteries, six samples of battery electrodes are provided below for detailed description.
[0042] Sample 1
[0043] The battery electrode provided by Sample 1 is an anode electrode, which includes an electrode body and a hydrogel layer, and the hydrogel layer is coated in the thinned area of the electrode body.
[0044] The pole piece body includes a current collector, a pole ear, a bottom coating and an active material layer. A plurality of pole ears are welded at intervals on one side of the current collector along the length direction. The bottom coating is coated on one side of the current collector, and the surface of the bottom coating is coated with an active material layer. The hydrogel layer is coated on the active material layer along the length direction of the pole piece body, and the hydrogel layer is horizontally centered.
[0045] Active material layer coating length L 活性物质层 The coating length of the hydrogel layer is 1746.0 mm. 水凝胶层 The coating width W of the hydrogel layer is 1742.0 mm, that is, the distance d between the end of one side of the hydrogel layer and the end of the adjacent active material layer is 2 mm. 水凝胶层 The coating thickness of the hydrogel layer is 3 mm. 水凝胶层 In addition, the hydrogel layer has a three-dimensional network structure, the cross-linking degree of the hydrogel layer is 70%, and the viscosity of the hydrogel layer is 6000 Pa·s.
[0046] Sample 2
[0047] Compared with sample 1, the coating thickness H of the hydrogel layer in the battery electrode provided by sample 2 is 水凝胶层 is 1mm.
[0048] Sample 3
[0049] Compared with sample 1, the coating thickness H of the hydrogel layer in the battery electrode provided by sample 3 is 水凝胶层 It is 0.1mm.
[0050] Sample 4
[0051] Compared with sample 1, the coating width W of the hydrogel layer in the battery electrode provided by sample 4 is 水凝胶层 It is 0.5mm.
[0052] Sample 5
[0053] Compared with sample 1, the coating width W of the hydrogel layer in the battery electrode provided by sample 5 is 水凝胶层 is 5mm.
[0054] Sample 6
[0055] Compared with sample one, the battery electrode provided by sample six is not provided with a hydrogel layer.
[0056] The battery electrodes of the above samples 1 to 6 were made into battery cells using the same preparation method, and the obtained battery cells were tested for flatness. The test results are as follows:
[0057] Table 1 Cell flatness test results of samples 1 to 6
[0058]
[0059] Comparing samples one to six, the battery electrodes of samples one to five are all coated with a hydrogel layer, while the battery electrode of sample six has no hydrogel layer. Combined with the results in Table 1, the battery cell flatness of samples one to five is better than that of sample six, indicating that the hydrogel layer can improve the consistency of the battery cell flatness, thereby improving the problem of lithium deposition at the head of the battery cell.
[0060] Among them, the difference between samples one to three is the different coating thickness of the hydrogel layer. Combined with the results in Table 1, if the coating thickness of the hydrogel layer is too thick, the head position of the battery cell will be relatively thicker; if the coating thickness of the hydrogel layer is too thick, the head position of the battery cell will be relatively thicker; if the coating thickness of the hydrogel layer is too thin, the head position of the battery cell will be relatively thin, thereby affecting the flatness of the battery cell.
[0061] In addition, the difference between samples one, four and five lies in the different coating widths of the hydrogel layer. Combined with the results in Table 1, if the coating width of the hydrogel layer is too thick, the head position of the battery cell will be relatively thick; if the coating width of the hydrogel layer is too thick, the head position of the battery cell will be relatively thick; if the coating width of the hydrogel layer is too thin, the head position of the battery cell will be relatively thin, thereby affecting the flatness of the battery cell.
[0062] The cells of samples 1 to 6 prepared above were made into lithium-ion batteries using the same preparation method, and the obtained lithium-ion batteries were cycled (5C CC to 4.20V, CV to 4.0C; 4.0C CC to 4.25V, CV to3.0C; 3.0C CC to 4.35V, CV to 2.0C; 2.0C CC to 4.50V, CV to 1.5C; 1.5C CC to4.53V, CV to 0.2C), and the expansion coefficient was calculated. The test results are as follows:
[0063] Table 2 Expansion coefficient results of lithium-ion batteries of samples 1 to 6
[0064]
[0065] Comparing samples one to six, the battery electrodes of samples one to five are all coated with a hydrogel layer, while the battery electrode of sample six has no hydrogel layer. Combined with the results in Table 1, the expansion coefficients of samples one to five are all smaller than the expansion coefficient of sample six, indicating that the hydrogel layer can improve the expansion of lithium-ion batteries.
[0066] Among them, the difference between samples one to three is the different coating thickness of the hydrogel layer. Combined with the results in Table 1, if the coating thickness of the hydrogel layer is too thick or too thin, it will affect the flatness of the battery cell, thereby affecting the expansion coefficient of the lithium-ion battery.
[0067] In addition, the difference between samples 1 to 3 is that the coating width of the hydrogel layer is different. Combined with the results in Table 1, if the coating width of the hydrogel layer is too thick or too thin, it will affect the flatness of the battery cell, thereby affecting the expansion coefficient of the lithium-ion battery.
[0068] To sum up, the new battery electrode of the utility model adds a hydrogel layer in the thinned area of the electrode body, utilizes the free deformation property of the hydrogel, and fills the gap at the head of the battery cell with the hydrogel layer when it is wound into a battery cell, which can maximize the flatness of the battery cell and thus improve the phenomenon of lithium deposition at the head of the battery cell.
[0069] The above description is only an embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the scope of the claims of the present invention.
Claims
1. A new type of battery pole piece, characterized in that: The invention comprises a pole piece body (1) and a hydrogel layer (2), wherein the hydrogel layer (2) is coated on the active material layer (14) of the pole piece body (1) along the length direction of the pole piece body (1), and the hydrogel layer (2) is located in the thinning area of the pole piece body (1).
2. The new battery pole piece according to claim 1 is characterized in that: The coating length L of the hydrogel layer (2) 水凝胶层 shorter than the coating length L of the active material layer (14) 活性物质层 3-5 mm, the coating width W of the hydrogel layer (2) 水凝胶层 The coating thickness H of the hydrogel layer (2) is 1 to 4 mm. 水凝胶层 It is 0.3~0.7mm.
3. The new battery pole piece according to claim 1 is characterized in that: The hydrogel layer (2) is coated horizontally and centrally on the active substance layer (14).
4. The new battery pole piece according to claim 1 is characterized in that: The hydrogel layer (2) has a three-dimensional network structure, the cross-linking degree of the hydrogel layer (2) is 10 to 90%, and the viscosity of the hydrogel layer (2) is 2500 to 9000 Pa·s.
5. The novel battery pole piece according to claim 1 is characterized in that: The pole piece body (1) is an anode piece.
6. The novel battery pole piece according to any one of claims 1 to 5, characterized in that: The pole piece body (1) comprises a current collector (11), a pole ear (12) and an active material layer (14); the pole ear (12) is arranged on one side of the current collector (11); and the active material layer (14) is coated on one side or both sides of the current collector (11).
7. The novel battery pole piece according to claim 6 is characterized in that: There are a plurality of pole tabs (12), and the plurality of pole tabs (12) are arranged at intervals along the length direction of the current collector (11).
8. The novel battery pole piece according to claim 6 is characterized in that: The pole piece body (1) further comprises a primer layer (13), wherein the primer layer (13) is coated on one side or both sides of the current collector (11), and the active material layer (14) is coated on the primer layer (13).
9. A battery cell, characterized in that: It comprises the novel battery electrode sheet as described in any one of claims 1 to 8, and also comprises a conventional battery electrode sheet and a diaphragm, wherein the electrode sheet body has an opposite polarity to the conventional battery electrode sheet, and the conventional battery electrode sheet, the diaphragm, the novel battery electrode sheet and the diaphragm are stacked in sequence and then wound into the battery core.
10. A lithium ion battery, characterized in that: The invention comprises the battery cell as claimed in claim 9, wherein the battery cell is encapsulated in a shell, and an electrolyte is injected into the shell.