Naked battery cell and battery
By setting a clearance area and covering it with a thickened layer at the tabs of the lithium-ion battery, the safety and energy density issues of the battery under external forces such as drops are solved, thereby improving the overall energy density and cycle life of the battery.
Patent Information
- Application Number
- CN202423306521.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-30
- Publication Date
- 2026-02-10
- Estimated Expiration
- 2034-12-30
AI Technical Summary
In the existing technology, handheld and wearable lithium-ion batteries are difficult to design and manufacture while ensuring battery performance and energy density, as well as battery safety under external forces such as drops. Furthermore, local overvoltage of the battery's electrodes affects the overall energy density and long-term cycle life.
A bare cell is designed by setting an avoidance area on the outermost surface of the electrode at the tab, and covering the avoidance area with a thickening layer. The thickening layer is a hot melt adhesive layer with a thickness of 25-50μm to avoid uneven thickness, improve the overall thickness consistency of the battery, and enhance the battery's safety and energy density.
It effectively prevents localized overvoltage of the electrode tabs caused by uneven thickness during battery manufacturing, improves the overall energy density and cycle performance of the battery, and enhances the safety and stability of the battery.
Smart Images
Figure CN223898545U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of battery technology, and in particular to a bare battery cell and battery. Background Technology
[0002] For handheld and wearable lithium-ion batteries, the design and manufacturing process faces the challenge of ensuring battery performance and energy density while guaranteeing battery safety under external forces such as drops. A common method is to apply hot melt adhesive tape to the outside of the battery. In traditional battery manufacturing methods, evenly distributed hot melt adhesive tape is often used.
[0003] Because the thickness of the battery core is inconsistent, uniformly setting the hot melt adhesive tape can easily lead to uneven thickness of the battery at positions such as the tabs compared to other positions, thus affecting the overall energy density of the battery. Furthermore, uneven thickness distribution can easily lead to local overvoltage of the battery electrodes, affecting the long-term cycle life of the battery.
[0004] Therefore, designing a bare cell and battery that can guarantee battery performance and energy density while maintaining safety is of paramount importance to those skilled in the art. Utility Model Content
[0005] The technical problem to be solved by this utility model is to provide a bare cell and battery that can ensure battery performance and energy density while maintaining safety, so as to solve the problem of local electrode overvoltage in the battery affecting the overall energy density and long-term cycle life of the battery in the prior art.
[0006] This utility model discloses a bare battery cell, which includes: a battery cell body and a thickening layer; the battery cell body includes an electrode sheet, and the electrode sheet is provided with a tab; the outer surface area of the outermost electrode sheet corresponding to the tab is a clearance area, and the outer surface area of the outermost electrode sheet is covered with a thickening layer, which is disposed to avoid the clearance area.
[0007] Optionally, the thickening layer is a hot melt adhesive layer.
[0008] Optionally, the adhesive strength of the hot melt adhesive layer is greater than or equal to 0.1 N / mm.
[0009] Optionally, the thickness of the thickening layer is 25-50 μm.
[0010] Optionally, the outer surface of the tab is covered with an insulating layer, the insulating layer at least covering the portion of the tab connected to the electrode, and the clearance area also includes the outer surface area of the outermost electrode corresponding to the insulating layer.
[0011] Optionally, the width of the bare battery cell is less than or equal to 40 mm.
[0012] Optionally, the electrode includes a positive electrode and a negative electrode, the tabs provided on the positive electrode are positive tabs, and the tabs provided on the negative electrode are negative tabs; the clearance area includes a first clearance area corresponding to the positive tab and a second clearance area corresponding to the negative tab.
[0013] Optionally, the outermost electrode is the positive electrode.
[0014] Optionally, the positive electrode includes a positive current collector, the tensile strength of which is greater than 250 N / mm². 2 .
[0015] Optionally, the positive current collector is aluminum foil.
[0016] Optionally, the outermost electrode is the negative electrode.
[0017] Optionally, the negative electrode includes a negative current collector, the tensile strength of which is greater than 400 N / mm². 2 .
[0018] Optionally, the negative electrode current collector is copper foil.
[0019] Optionally, the bare battery cell is a wound battery cell.
[0020] Optionally, the tab is located at the top of the bare cell in the height direction, and a reinforcement layer is provided at the bottom of the bare cell in the height direction. The reinforcement layer covers the outer surface of the outermost electrode. The outer surface area of the outermost electrode corresponding to the reinforcement layer is a third clearance area, and the thickening layer is disposed to avoid the third clearance area.
[0021] Optionally, the reinforcing layer is a bottom wrapping adhesive, which wraps around the bottom end of the bare cell and is bonded to the two outer surfaces and the bottom end face of the bare cell.
[0022] To address the problems existing in the prior art, this utility model also provides a battery, which includes a bare cell as described in any of the preceding claims, and further includes a protective film for accommodating the bare cell.
[0023] Optionally, the protective film is made of aluminum-plastic film.
[0024] Compared with the prior art, the beneficial effects of the bare cell provided by this utility model embodiment are as follows: by using the outer surface area of the outermost electrode corresponding to the tab as a clearance area, when the thickening layer is covered on the outer surface area of the outermost electrode, the thickening layer is set to avoid the clearance area, which makes the overall thickness of the bare cell covered with the thickening layer more uniform. This effectively prevents local tab overvoltage caused by uneven thickness during subsequent battery manufacturing, and effectively improves the overall energy density of the cell and enhances the cycle performance of the battery. Attached Figure Description
[0025] The technical solution of this utility model will be further described in detail below with reference to the accompanying drawings and embodiments. In the accompanying drawings:
[0026] Figure 1 This is a schematic diagram of the structure of the bare battery cell provided in this embodiment of the utility model;
[0027] Figure 2 This is a schematic diagram of the structure of the core body provided in this embodiment of the utility model. Figure 1 ;
[0028] Figure 3 This is a schematic diagram of the structure of the core body provided in this embodiment of the utility model. Figure 2 ;
[0029] Figure 4 This is a schematic diagram of the battery structure provided in an embodiment of the present invention.
[0030] The labels for the attached figures are as follows:
[0031] 100. Cell body; 200. Thickened layer; 110. Electrode; 111. Tab; 112. Clearance area; 113. Insulation layer; 114. Reinforcing layer; 1101. Positive electrode; 1102. Negative electrode; 1111. Positive tab; 1112. Negative tab; 1123. Third clearance area; 20. Protective film. Detailed Implementation
[0032] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The preferred embodiments of this utility model will now be described in detail with reference to the accompanying drawings.
[0033] like Figures 1 to 3 As shown, this utility model provides a specific embodiment of a bare battery cell.
[0034] A type of bare battery cell, reference Figure 1The battery cell body 100 includes a battery cell body 100 and a thickening layer 200. The battery cell body 100 includes an electrode 110, on which a tab 111 is provided. The outer surface area of the outermost electrode 110 corresponding to the tab 111 is a clearance area 112. The outer surface area of the outermost electrode 110 is covered by the thickening layer 200, which is set to avoid the clearance area 112.
[0035] Specifically, refer to Figure 1 The cell body 100 is the core component of the battery. As the energy storage unit of the battery, it can store electrical energy for later use. When the battery is charging, the cell converts electrical energy into chemical energy for storage. When energy needs to be released, the cell converts the stored chemical energy into electrical energy to supply external devices. The safety and stability of the cell body 100 directly affect the quality of the battery. The thickened layer 200 is used to ensure the safety of the cell body 100 under external forces such as drops.
[0036] The energy storage and release of the cell body 100 depends on the electrode 110. The electrode 110 is responsible for electron flow and ion transfer. The electrode 110 is provided with tabs 111 to connect the internal and external circuits of the cell body 100, so as to realize the energy transfer between the cell body 100 and the external circuit. Since the tabs 111 themselves have a certain thickness, when the tabs 111 are placed on the electrode 110, the area on the outer surface of the outermost electrode 110 corresponding to the position of the tabs 111 will protrude further outward. If the thickening layer 200 is covered on the entire outer surface of the outermost electrode 110, the thickness of the entire bare cell will be uneven, which will affect the overall energy density of the cell. In the subsequent battery manufacturing process, the uneven thickness of the cell can easily lead to local overvoltage of the tabs 111, affecting the cycle life of the product.
[0037] In this embodiment, the outer surface area of the outermost electrode 110 corresponding to the tab 111 is designated as the avoidance area 112. When the thickening layer 200 is covered on the outer surface area of the outermost electrode 110, the thickening layer 200 is positioned to avoid the avoidance area 112. This makes the overall thickness of the bare cell covered with the thickening layer 200 more uniform, thereby effectively preventing local overvoltage of the tab 111 caused by uneven thickness during subsequent battery manufacturing, and effectively improving the overall energy density of the cell and enhancing the cycle performance of the battery.
[0038] In one embodiment, the thickening layer 200 is a hot melt adhesive layer.
[0039] Specifically, the hot melt adhesive layer can act as a shock absorber and buffer, reducing the risk of damage to the battery cell body 100 when subjected to external impacts or vibrations, and improving the reliability and stability of the battery cell body 100. In addition, the hot melt adhesive layer also has insulating properties, which can effectively electrically isolate the battery cell body 100 from external components to provide insulation protection and prevent short circuits or electrical accidents. On the other hand, the hot melt adhesive layer can provide waterproof and dustproof protection to prevent moisture and dust from entering the battery cell body 100, thereby improving the reliability and durability of the battery cell body 100. Furthermore, the hot melt adhesive layer can also provide some convenience during subsequent maintenance, as it can be relatively easy to disassemble and replace.
[0040] In one embodiment, the adhesive strength of the hot melt adhesive layer is greater than or equal to 0.1 N / mm.
[0041] Specifically, adhesive force has a significant impact on stability. Excessive adhesive force will affect the heat dissipation of the entire bare cell, hindering the transfer and dissipation of heat and causing the cell to overheat. Insufficient adhesive force can easily lead to unstable connections, making the cells prone to detachment when subjected to external impacts or vibrations, thus affecting the protection effect.
[0042] In one embodiment, the thickness of the thickening layer 200 is 25-50 μm.
[0043] Specifically, since the tab 111 itself has a certain thickness, when the tab 111 is placed on the electrode 110, the area on the outermost electrode 110 corresponding to the position of the tab 111 will protrude further outward, with a protrusion height of 25-50μm. By setting the thickness of the thickening layer 200 to 25-50μm, when the thickening layer 200 covers the outer surface of the outermost electrode 110 and avoids the avoidance area 112, the overall thickness of the bare cell covered with the thickening layer 200 can be made uniform. This effectively prevents local overvoltage of the tab 111 caused by uneven thickness during subsequent battery manufacturing, and effectively improves the overall energy density of the cell and enhances the cycle performance of the battery.
[0044] In one embodiment, reference Figure 1 The outer surface of the tab 111 is covered with an insulating layer 113, which at least covers the portion of the tab 111 connected to the electrode 110. The clearance area 112 also includes the outer surface area of the outermost electrode 110 corresponding to the insulating layer 113.
[0045] Specifically, refer to Figure 1Since the insulating layer 113 itself has a certain thickness, when the insulating layer 113 is placed on the area where the tab 111 is connected to the electrode 110, the area on the outer surface of the outermost electrode 110 corresponding to the position of the insulating layer 113 will also protrude further outward. Therefore, when the thickening layer 200 is covered on the outer surface area of the outermost electrode 110, the thickening layer 200 avoids the outer surface area of the outermost electrode 110 corresponding to the insulating layer 113, which makes the overall thickness of the bare cell covered with the thickening layer 200 more consistent.
[0046] In one embodiment, the width of the bare cell is less than or equal to 40mm. For narrow batteries, the design of their protection structure is more difficult. By setting the thickening layer 200 in the above manner, the protection of the bare cell of the narrow battery can be made simpler and more stable.
[0047] In one embodiment, reference Figures 1 to 3 The electrode 110 includes a positive electrode 1101 and a negative electrode 1102. The tab 111 provided on the positive electrode 1101 is the positive tab 1111, and the tab 111 provided on the negative electrode 1102 is the negative tab 1112. The clearance area 112 includes a first clearance area corresponding to the positive tab 1111 and a second clearance area corresponding to the negative tab 1112.
[0048] Option 1
[0049] refer to Figure 2 The outermost electrode 110 is the positive electrode 1101, which includes a positive current collector. The tensile strength of the positive current collector is greater than 250 N / mm². 2 .
[0050] Specifically, the positive current collector is an electrode material used to transmit and collect current. It has good conductivity. Since the thickened layer 200 needs to be directly bonded to the outer surface of the positive current collector, the tensile strength of the positive current collector is set to be greater than 250 N / mm². 2 The range can effectively prevent the positive current collector of the bare cell from breaking during a drop.
[0051] Option 2
[0052] refer to Figure 3 The outermost electrode 110 is the negative electrode 1102, which includes a negative current collector. The tensile strength of the negative current collector is greater than 400 N / mm². 2 .
[0053] Specifically, the negative current collector is also an electrode material used to transmit and collect current. It has good conductivity. Since the thickened layer 200 needs to be directly pasted onto the outer surface of the negative current collector, the tensile strength of the positive current collector is set to be greater than 400 N / mm².2 The range can effectively prevent the positive current collector of the bare cell from breaking during a drop.
[0054] In one embodiment, the positive current collector is an aluminum foil, and the negative current collector is a copper foil. In the electrochemical reaction, a significant difference in potential between the positive and negative electrodes is required to generate current. By using aluminum foil and copper foil as the positive and negative electrodes respectively, the difference in standard electrode potentials between aluminum and copper can be utilized, i.e., the standard electrode potential of aluminum is more negative than that of copper, so that a potential difference is generated between the positive and negative current collectors, thereby realizing the flow of current.
[0055] In one embodiment, the bare cell is a wound cell, which is formed by stacking and winding the positive and negative electrodes. This allows the positive and negative electrode materials to be wrapped in a more compact space, resulting in a cell with higher energy density.
[0056] In one embodiment, reference Figure 2 The tab 111 is located at the top of the bare cell in the height direction, and the bottom of the bare cell in the height direction is provided with an enhancement layer 114. The enhancement layer 114 covers the outer surface of the outermost electrode 110. The outer surface area of the outermost electrode 110 corresponding to the enhancement layer 114 is the third avoidance area 1123. The thickening layer 200 is set to avoid the third avoidance area 1123.
[0057] Specifically, the reinforcement layer 114 is used to prevent the electrode 110 from flipping when the bare cell is dropped. Since the reinforcement layer 114 itself has a certain thickness, when the reinforcement layer 114 is set at the bottom of the bare cell in the height direction, the outer surface of the bare cell will also protrude more outward in this area. By setting the thickening layer 200 to avoid the third avoidance area 1123, the overall thickness of the bare cell covered with the thickening layer 200 can be made more uniform.
[0058] In one embodiment, the reinforcing layer 114 is a bottom-wrap adhesive, which wraps around the bottom of the bare cell and is bonded to the two outer surfaces and the bottom end face of the bare cell. By wrapping the bottom of the bare cell and the two outer surfaces and the bottom end face of the bare cell with adhesive, the bare cell can be more comprehensively protected to prevent the electrode 110 from flipping when the bare cell is dropped.
[0059] like Figure 4 As shown, this utility model also provides a specific embodiment of a battery.
[0060] A type of battery, reference Figure 4 It includes the bare battery cell of any of the above, and also includes the protective film 20 that houses the bare battery cell.
[0061] Specifically, the protective film 20 is made of aluminum-plastic film.
[0062] It should be understood that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Those skilled in the art can modify the technical solutions described in the above embodiments, or make equivalent substitutions for some of the technical features; and all such modifications and substitutions should fall within the protection scope of the appended claims of this utility model.
Claims
1. A bare battery cell, characterized in that, include: The battery cell body includes an electrode sheet with a tab on it; the outer surface area of the outermost electrode sheet corresponding to the tab is a clearance area, and the outer surface area of the outermost electrode sheet is covered with a thickening layer, which is disposed away from the clearance area.
2. A bare battery cell according to claim 1, characterized in that, The thickening layer is made of hot melt adhesive.
3. A bare battery cell according to claim 2, characterized in that, The adhesive strength of the hot melt adhesive layer is greater than or equal to 0.1 N / mm.
4. A bare battery cell according to claim 1, characterized in that, The thickness of the thickening layer is 25-50 μm.
5. A bare battery cell according to claim 1, characterized in that, The outer surface of the tab is covered with an insulating layer, which at least covers the portion of the tab connected to the electrode plate. The clearance area also includes the outer surface region of the outermost electrode plate corresponding to the insulating layer.
6. A bare battery cell according to claim 1, characterized in that, The width of the bare battery cell is less than or equal to 40 mm.
7. A bare battery cell according to claim 1, characterized in that, The electrode includes a positive electrode and a negative electrode, the tabs provided on the positive electrode are positive tabs, and the tabs provided on the negative electrode are negative tabs; the clearance area includes a first clearance area corresponding to the positive tab and a second clearance area corresponding to the negative tab.
8. A bare battery cell according to claim 7, characterized in that, The outermost electrode is the positive electrode.
9. A bare battery cell according to claim 8, characterized in that, The positive electrode includes a positive current collector, and the tensile strength of the positive current collector is greater than 250 N / mm². 2 .
10. A bare battery cell according to claim 9, characterized in that, The positive current collector is aluminum foil.
11. A bare battery cell according to claim 7, characterized in that, The outermost electrode is the negative electrode.
12. A bare battery cell according to claim 11, characterized in that, The negative electrode includes a negative current collector, and the tensile strength of the negative current collector is greater than 400 N / mm². 2 .
13. A bare battery cell according to claim 12, characterized in that, The negative electrode current collector is copper foil.
14. A bare battery cell according to claim 7, characterized in that, The bare battery cell is a wound battery cell.
15. A bare battery cell according to claim 1, characterized in that, The tab is located at the top of the bare cell in the height direction, and a reinforcement layer is provided at the bottom of the bare cell in the height direction. The reinforcement layer covers the outer surface of the outermost electrode. The outer surface area of the outermost electrode corresponding to the reinforcement layer is the third clearance area, and the thickening layer is set to avoid the third clearance area.
16. A bare battery cell according to claim 15, characterized in that, The reinforcing layer is a bottom-wrap adhesive, which wraps around the bottom end of the bare cell and is bonded to the two outer surfaces and the bottom end face of the bare cell.
17. A battery, characterized in that, It includes the bare battery cell as described in any one of claims 1-16, and further includes a protective film accommodating the bare battery cell.
18. The battery according to claim 17, characterized in that, The protective film is made of aluminum-plastic film.