Cathode plate, battery cell and battery
By designing a protective adhesive and a second active material layer on the cathode sheet, the problem of lithium deposition at the edge of the anode tab in lithium-ion batteries is solved, achieving high battery safety performance, preventing lithium dendrites from piercing the separator, and improving battery safety.
Patent Information
- Application Number
- CN202422784638.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-14
- Publication Date
- 2025-11-11
- Estimated Expiration
- 2034-11-14
AI Technical Summary
During the charging and discharging process of lithium-ion batteries, lithium plating is prone to occur at the edge of the anode tab, which can cause lithium dendrites to pierce the separator, resulting in a short circuit in the battery and affecting the battery's safety performance.
Design a cathode sheet including a cathode current collector and an electrode protective adhesive. The electrode protective adhesive has a second active material layer spaced apart from the first active material layer to prevent lithium ions from being extracted. A second active material layer is provided at the anode tab to block welding burrs and prevent the diaphragm from being punctured.
It effectively prevents lithium plating and lithium dendrites from piercing the separator, improves battery safety performance, prevents short circuits between positive and negative electrodes, and enhances battery safety.
Smart Images
Figure CN223539612U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of lithium battery technology, and in particular to a cathode sheet, a battery cell, and a battery. Background Technology
[0002] During the charging and discharging process of a lithium-ion battery, the current density is unevenly distributed. The current transmission path is relatively short near the anode tab, so the current density is the highest at that location. This high current density leads to lithium plating at the edge of the anode tab. Currently, green or yellow adhesive is generally used to directly cover the cathode active material to prevent lithium ions from escaping to the anode and thus prevent lithium plating.
[0003] However, during long-cycle charging and discharging of the battery, some lithium ions will still be released from the areas covered by green or yellow adhesive, resulting in lithium plating at the edge of the anode tab. In severe cases, the deposited lithium dendrites can puncture the separator, causing the battery to short-circuit and fail, resulting in low battery safety performance. Utility Model Content
[0004] The main purpose of this invention is to propose a cathode sheet that aims to improve the phenomenon of lithium plating at the edge of the anode tab.
[0005] To achieve the above objectives, this utility model proposes a cathode plate, which includes:
[0006] A cathode current collector has a first surface and a second surface disposed opposite to each other. Both the first surface and the second surface are provided with a first active material layer. A first groove is provided on the first active material layer.
[0007] An electrode protective adhesive is disposed in the first groove, and a second active material layer is provided on the surface of the electrode protective adhesive, the second active material layer being disposed at an interval from the first active material layer.
[0008] In some embodiments, the electrode protective adhesive includes a protective adhesive layer, the protective adhesive layer having a third surface and a fourth surface disposed opposite to each other along its thickness direction, and both the third surface and the fourth surface of the protective adhesive layer are adhesive.
[0009] The third surface is connected to the first surface of the cathode current collector, and the fourth surface is connected to the second active material layer. The projected area of the second active material layer on the cathode current collector is smaller than the projected area of the protective adhesive layer on the cathode current collector.
[0010] In some embodiments, the distance between the first active material layer and the second active material layer is greater than or equal to 1 mm.
[0011] In some embodiments, the thickness of the protective adhesive layer is H1, the thickness of the first active material layer is H2, and the thickness of the second active material layer is H3, satisfying H2≤H1+H3.
[0012] In some embodiments, the compaction density of the first active material layer is M1, and the compaction density of the second active material layer is M2, satisfying M1≥M2.
[0013] This utility model also proposes a battery cell, including an anode plate, a separator, and a cathode plate, wherein the separator is disposed between the anode plate and the cathode plate, and the anode plate, the separator, and the cathode plate are stacked and wound together to form the battery cell;
[0014] The cathode sheet mentioned above is the cathode sheet described in the previous description.
[0015] In some embodiments, the anode sheet is provided with anode tabs, which are correspondingly disposed with the second active material layer, and the width of the anode tabs is smaller than the width of the second active material layer.
[0016] In some embodiments, the anode sheet includes an anode current collector, the anode current collector having a fifth surface and a sixth surface disposed opposite to each other, both the fifth surface and the sixth surface having a third active material layer, the third active material layer having a second groove, and the anode tab being disposed in the second groove.
[0017] In some embodiments, the surface of the third active material layer is provided with tab protective adhesive, which covers the second groove.
[0018] This utility model also proposes a battery, which includes a casing and the aforementioned battery cell, wherein the battery cell is disposed in the casing.
[0019] The cathode sheet provided by this utility model includes a cathode electrode body and an electrode protective adhesive. A first active material layer is provided on the surface of the cathode electrode body, and a second active material layer is provided on the electrode protective adhesive. The first active material layer on the cathode electrode body and the second active material layer on the electrode protective adhesive are spaced apart, thus preventing them from conducting. When the cathode sheet is applied to a battery, even with prolonged charging and discharging or high-rate charging and discharging, lithium plating will not occur at this location, and lithium dendrites will not pierce the separator, causing a short circuit. This results in high battery safety. Furthermore, the second active material layer is correspondingly positioned to the anode tab, blocking welding burrs on the anode tab and preventing them from piercing the separator and causing a short circuit between the positive and negative electrodes, further improving battery safety. Attached Figure Description
[0020] Figure 1This is a schematic diagram of the cathode plate in one embodiment of the present invention;
[0021] Figure 2 This is a schematic diagram of the adhesive paper structure in one embodiment of the present invention;
[0022] Figure 3 This is a schematic diagram of the adhesive tape from another perspective in one embodiment of the present invention;
[0023] Figure 4 This is a partial structural diagram of the battery cell in one embodiment of the present invention.
[0024] Explanation of icon numbers:
[0025] label name label name 100 cathode plate 110 Cathode current collector 111 First active substance layer 112 First groove 120 Electrode Protective Coating 121 Second active substance layer 122 Protective adhesive layer 123 foam layer 200 Anode plate 201 Anode tab 210 Anode current collector 211 Third active substance layer 212 Second groove
[0026] The realization of the purpose, functional features and advantages of this utility model will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation
[0027] The solutions in the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. Based on the embodiments of this utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of this utility model.
[0028] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in this utility model embodiment are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.
[0029] It should also be noted that when a component is described as "fixed to" or "set on" another component, it can be directly on the other component or there may be an intervening component present. When a component is described as "connected to" another component, it can be directly connected to the other component or there may be an intervening component present.
[0030] Furthermore, the use of terms such as "first" and "second" in this utility model is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed by this utility model.
[0031] This utility model embodiment provides a cathode sheet 100, referring to... Figure 1 The cathode plate 100 includes:
[0032] The cathode current collector 110 has a first surface and a second surface disposed opposite to each other. Both the first and second surfaces are provided with a first active material layer 111, and the first active material layer 111 has a first groove 112. Specifically, an electrode protective adhesive 120 is attached to the surface of the cathode current collector 110. Then, an active material is coated onto the surface of the cathode current collector 110, and the active material covers the electrode protective adhesive 120. After the active material is coated onto the surface of the cathode current collector 110, the first groove 112 is formed at the location where the electrode protective adhesive 120 is attached. The active material on the surface of the cathode current collector 110 forms the first active material layer 111. The shape and size of the first groove 112 are adapted to the electrode protective adhesive 120. Optionally, when the electrode protective adhesive 120 is square, a square first groove 112 is formed; or, when the electrode protective adhesive 120 is rectangular, a rectangular first groove 112 is formed.
[0033] An electrode protective adhesive 120 is disposed in the first groove 112, and a second active material layer 121 is provided on the surface of the electrode protective adhesive 120. The second active material layer 121 is disposed alternately with the first active material layer 111. As can be seen from the aforementioned description of the electrode protective adhesive 120, the surface of the electrode protective adhesive 120 is coated with an active material, and the active material on the surface of the electrode protective adhesive 120 forms the second active material layer 121, wherein the second active material layer 121 is disposed alternately with the first active material layer 111.
[0034] The cathode sheet provided by this utility model includes a cathode current collector 110 and an electrode protective adhesive 120. A first active material layer 111 is provided on the surface of the cathode current collector 110, and a second active material layer 121 is provided on the electrode protective adhesive 120. The first active material layer 111 on the surface of the cathode current collector 110 and the second active material layer 121 on the electrode protective adhesive 120 are spaced apart, thus preventing the first active material layer 111 and the second active material layer 121 from conducting. When the cathode sheet 100 is applied to a battery, even with prolonged charging and discharging or high-rate charging and discharging, lithium plating will not occur at this location, and lithium dendrites will not pierce the separator, causing a short circuit. The battery has high safety performance. Furthermore, the second active material layer 121 is correspondingly positioned to the anode tab 201, blocking welding burrs on the anode tab 201 and preventing them from piercing the separator and causing a short circuit between the positive and negative electrodes, further improving the battery's safety performance.
[0035] In some embodiments, refer to Figure 2 and Figure 3 The electrode protective adhesive 120 includes a protective adhesive layer 122. The protective adhesive layer 122 has a third surface and a fourth surface disposed opposite to each other along its thickness direction. Both the third surface and the fourth surface of the protective adhesive layer 122 are adhesive. The third surface is connected to the first surface of the cathode current collector 110, and the fourth surface is connected to the second active material layer 121. The projected area of the second active material layer 121 on the cathode current collector 110 is smaller than the projected area of the protective adhesive layer 122 on the cathode current collector 110. The protective adhesive layer 122 has both a third and a fourth surface that are adhesive. The third surface is directly adhered to the cathode current collector 110, and the fourth surface is adhered to the second active material layer 121. Before the cathode sheet 100 is baked, the second active material layer 121 is surrounded by a foamed adhesive layer 123, which is also adhered to the fourth surface. The side of the foamed adhesive layer 123 that is adhered to the fourth surface has a peelable additive. After the electrode protective adhesive 120 is adhered to the cathode current collector 110 and the active material is coated, the cathode sheet 100 needs to be dried in order to make the active material adhere better to the surface of the cathode current collector 110. During the baking process, the foamed adhesive layer 123 will gradually peel off the protective adhesive layer 122 until the foamed adhesive layer 123 falls off, so that the second active material layer 121 surrounded by the foamed adhesive layer 123 is spaced apart from the first active material layer 111 on the surface of the cathode current collector 110.
[0036] In some embodiments, the distance between the first active material layer 111 and the second active material layer 121 is greater than or equal to 1 mm. Before the cathode sheet 100 is baked, a foam adhesive layer 123 is provided at the interval between the first active material layer 111 and the second active material layer 121. During the baking process of the cathode sheet 100, the foam adhesive layer 123 expands due to heat. When the distance between the first active material layer 111 and the second active material layer 121 is greater than or equal to 1 mm, the foam adhesive layer 123 will detach smoothly, thereby forming a spacer channel between the first active material layer 111 and the second active material layer 121.
[0037] In some embodiments, the thickness of the protective adhesive layer 122 is H1, the thickness of the first active material layer 111 is H2, and the thickness of the second active material layer 121 is H3, satisfying H2≤H1+H3. When the cathode sheet is applied to the battery cell, it needs to be wound. The thickness of the first active material layer 111, H2≤H1+H3, can reduce the thickness of the battery cell and increase its flatness. In this embodiment, the foamed adhesive layer 123 is made of a foaming agent or resin. The foaming agent is a substance that can generate gas under specific conditions, causing the material to form a structure containing a large number of micropores. In this embodiment, when the cathode sheet 100 is baked, the foaming agent causes the entire foamed adhesive layer 123 to contain a large number of micropores, thus gradually detaching from the protective adhesive layer 122. The resin is a substance that softens when heated. When the cathode sheet 100 is baked, the resin softens due to heat, thus gradually detaching from the protective adhesive layer 122. Of course, the foamed adhesive layer 123 can also be made of rubber, and this is not a limitation.
[0038] In some embodiments, the compaction density of the first active material layer 111 is M1, and the compaction density of the second active material layer 121 is M2, satisfying M1≥M2. The first active material layer 111 is directly coated on the surface of the cathode current collector 110, and the second active material layer 121 is adhered to the fourth surface of the protective adhesive layer 122. Normally, the compaction density M1 of the first active material layer 111 is equal to the compaction density M2 of the second active material layer 121. However, to ensure a more stable adhesion of the second active material layer 121 to the protective adhesive layer 122, the compaction density of the second active material layer 121 may be reduced, thus M1≥M2.
[0039] This utility model also proposes a battery cell, referring to... Figure 4The battery cell includes an anode plate 200, a diaphragm, and a cathode plate 100. The diaphragm is disposed between the anode plate 200 and the cathode plate 100. The anode plate 200, the diaphragm, and the cathode plate 100 are stacked and wound together to form a battery cell. The cathode plate 100 is the same as described above. Since this battery cell adopts all the technical solutions of all the above embodiments, it has at least all the technical effects brought about by the technical solutions of the above embodiments, which will not be repeated here.
[0040] In some embodiments, the anode plate 200 is provided with an anode tab 201, which is correspondingly disposed with the second active material layer 121, and the width of the anode tab 201 is smaller than the width of the second active material layer 121. The anode tab 201 is welded to the anode plate 200. After welding, welding burrs will exist around the anode tab 201. These burrs can easily puncture the separator, causing direct contact between the positive and negative electrodes and resulting in a short circuit, leading to low battery safety. When the anode tab 201 is correspondingly disposed with the second active material layer 121, and the width of the anode tab 201 is smaller than the width of the second active material layer 121, the second active material layer 121 can prevent the welding burrs from puncturing the separator and directly contacting the cathode plate 100, thus preventing direct contact between the positive and negative electrodes and resulting in a short circuit, and improving battery safety.
[0041] In some embodiments, the anode sheet 200 includes an anode current collector 210, which has a fifth surface and a sixth surface disposed opposite to each other. Both the fifth and sixth surfaces are provided with a third active material layer 211. The third active material layer 211 has a second groove 212 formed therein, and the anode tab 201 is disposed in the second groove 212. The second groove 212 can be obtained by cleaning a small portion of the active material on the third active material layer 211 using laser cleaning (or mechanical cleaning, foam cleaning). After forming the second groove 212, the anode tab 201 can be directly welded to the anode current collector 210 to ensure a firm weld.
[0042] In some embodiments, the surface of the third active material layer 211 is provided with tab protective adhesive 213, which covers the second groove 212. The anode tab 201 is welded in the second groove 212. After welding, welding burrs will be generated around the anode tab. The tab protective adhesive 213 is used to seal the anode tab in the second groove 212 to prevent the welding burrs from piercing the separator and causing a short circuit in the battery.
[0043] This utility model embodiment also proposes a battery, which includes a casing and the aforementioned battery cell, with the battery cell disposed within the casing. Since this battery employs all the technical solutions of all the above embodiments, it possesses at least all the technical effects brought about by the technical solutions of the above embodiments, and will not be elaborated upon further here.
[0044] The above description is only a part or preferred embodiment of this utility model. Neither the text nor the drawings should limit the scope of protection of this utility model. All equivalent structural transformations made using the content of this utility model specification and drawings under the overall concept of this utility model, or direct / indirect applications in other related technical fields, are included within the scope of protection of this utility model.
Claims
1. A cathode plate, characterized in that, include: A cathode current collector has a first surface and a second surface disposed opposite to each other. Both the first surface and the second surface are provided with a first active material layer. A first groove is provided on the first active material layer. An electrode protective adhesive is disposed in the first groove, and a second active material layer is provided on the surface of the electrode protective adhesive, the second active material layer being disposed at an interval from the first active material layer.
2. The cathode sheet according to claim 1, characterized in that, The electrode protective adhesive includes a protective adhesive layer, the protective adhesive layer having a third surface and a fourth surface disposed opposite to each other along its thickness direction, and both the third surface and the fourth surface of the protective adhesive layer are adhesive. The third surface is connected to the first surface of the cathode current collector, and the fourth surface is connected to the second active material layer. The projected area of the second active material layer on the cathode current collector is smaller than the projected area of the protective adhesive layer on the cathode current collector.
3. The cathode sheet according to claim 2, characterized in that, The distance between the first active material layer and the second active material layer is greater than or equal to 1 mm.
4. The cathode sheet according to claim 2, characterized in that, The thickness of the protective adhesive layer is H1, the thickness of the first active material layer is H2, and the thickness of the second active material layer is H3, satisfying H2≤H1+H3.
5. The cathode sheet according to claim 4, characterized in that, The compaction density of the first active material layer is M1, and the compaction density of the second active material layer is M2, satisfying M1≥M2.
6. A battery cell, characterized in that, The battery cell includes an anode plate, a diaphragm, and a cathode plate, wherein the diaphragm is disposed between the anode plate and the cathode plate, and the anode plate, the diaphragm, and the cathode plate are stacked and wound together to form the battery cell. The cathode sheet is the cathode sheet as described in any one of claims 1-5.
7. The battery cell according to claim 6, characterized in that, The anode plate is provided with anode tabs, which are correspondingly disposed with the second active material layer, and the width of the anode tabs is smaller than the width of the second active material layer.
8. The battery cell according to claim 7, characterized in that, The anode plate includes an anode current collector, which has a fifth surface and a sixth surface disposed opposite to each other. Both the fifth surface and the sixth surface are provided with a third active material layer. The third active material layer is provided with a second groove, and the anode tab is disposed in the second groove.
9. The battery cell according to claim 8, characterized in that, The surface of the third active material layer is provided with tab protective adhesive, which covers the second groove.
10. A battery, characterized in that, It includes a housing and a battery cell as described in any one of claims 6-9, wherein the battery cell is disposed in the housing.