A battery pole piece and a battery

Abstract

The application provides a battery pole piece and a battery, wherein the battery pole piece comprises a current collector, an active coating and a protective layer; the active coating is arranged on the current collector, and the protective layer is located on the active coating; the current collector is provided with a first groove, and the protective layer covers the first groove. By arranging the first groove on the current collector, a channel for electrolyte flow is formed, accumulation and continuous reaction of electrolyte in the lithium ion battery are avoided, the electrochemical stability in the lithium ion battery is improved, and the performance decay rate of the lithium ion battery in the actual charging and discharging process is slowed down.

Description

Technical Field

[0001] This application relates to the field of battery technology, specifically to a battery electrode and a battery. Background Technology

[0002] Lithium-ion batteries have the advantage of high energy density and are widely used in various fields.

[0003] Under high voltage conditions, the electrochemical stability inside lithium-ion batteries is poor during charge-discharge cycles, making it easy for parts such as adhesive tape or active paste inside the lithium-ion battery to break or fall off. This results in a faster performance degradation rate of lithium-ion batteries during actual charge-discharge processes. Summary of the Invention

[0004] The purpose of this application is to provide a battery electrode and a battery to solve the problem of rapid performance degradation rate of lithium-ion batteries during actual charging and discharging processes.

[0005] In a first aspect, embodiments of this application provide a battery electrode, comprising:

[0006] Current collector, active coating, and protective layer;

[0007] The active coating is disposed on the current collector, the protective layer is located on the active coating, the current collector is provided with a first groove, and the protective layer covers the first groove.

[0008] Optionally, the active coating is provided with a second groove, and the protective layer covers the second groove.

[0009] Optionally, the first trench and the second trench are interconnected.

[0010] Optionally, the protective layer includes a first portion on the current collector and a second portion on the active coating, the first portion covering the first trench and the second portion covering the second trench.

[0011] Optionally, the second trench includes a first trench segment and a second trench segment extending from the first trench segment;

[0012] The depth of the first groove segment is greater than the depth of the second groove segment.

[0013] Optionally, the extension direction of the first groove is consistent with the length or width direction of the current collector.

[0014] Optionally, the extension direction of the second groove is consistent with the length or width direction of the current collector.

[0015] Optionally, the cross-section of the first trench is polygonal, circular, elliptical, or U-shaped, and / or the cross-section of the first trench is polygonal, circular, elliptical, or U-shaped.

[0016] Optionally, the depth of the first trench is less than the thickness of the current collector.

[0017] Optionally, the depth of the second trench is less than or equal to the thickness of the active coating.

[0018] Secondly, embodiments of this application provide a battery, including the battery electrode as described in the first aspect, wherein the protective layer is located at the end of the battery electrode.

[0019] Thirdly, embodiments of this application provide a battery, including a battery electrode as described in the first aspect and a tab located on the battery electrode, wherein the protective layer is located on the battery electrode at a position corresponding to the tab.

[0020] The above technical solution has the following advantages or beneficial effects:

[0021] The battery electrode and battery provided in this application embodiment form a channel for electrolyte flow by setting a first groove on the current collector, thereby avoiding the accumulation and continuous reaction of electrolyte inside the lithium-ion battery, improving the electrochemical stability inside the lithium-ion battery, and slowing down the performance degradation rate of the lithium-ion battery during actual charging and discharging. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of a battery electrode provided in an embodiment of this application;

[0023] Figure 2 This is a schematic diagram of another battery electrode structure provided in an embodiment of this application;

[0024] Figure 3 This is a schematic diagram of the structure of another battery electrode provided in the embodiments of this application;

[0025] Figure 4 This is a schematic diagram of another battery electrode provided in the embodiments of this application;

[0026] Figure 5 This is a schematic diagram of the interconnected first and second trenches provided in an embodiment of this application;

[0027] Figure 6 This is a schematic diagram of the parallel arrangement of the second trenches provided in an embodiment of this application;

[0028] Figure 7 This is a schematic diagram of the second groove provided in an embodiment of this application, which is arranged in a vertical stripe pattern;

[0029] Figure 8 This is a schematic diagram of the second groove with diagonal stripes provided in an embodiment of this application;

[0030] Figure 9 This is a schematic diagram of the second trench arranged in a grid pattern according to an embodiment of this application;

[0031] Figure 10 This is a schematic diagram of the structure of a wound battery cell provided in an embodiment of this application. Detailed Implementation

[0032] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0033] Please see Figure 1 , Figure 1 This is a schematic diagram of the structure of a battery electrode provided in an embodiment of this application, as shown below. Figure 1 As shown, the above-mentioned battery electrode includes:

[0034] Current collector 10, active coating 20 and protective layer 40;

[0035] The active coating 20 is disposed on the current collector 10, the protective layer 40 is located on the active coating 20, the current collector 10 is provided with a first groove 11, and the protective layer 40 covers the first groove 11.

[0036] like Figure 1 As shown, by setting the first groove 11 on the current collector 10, a channel for electrolyte flow is formed, which avoids the accumulation and continuous reaction of electrolyte inside the lithium-ion battery, improves the electrochemical stability inside the lithium-ion battery, avoids the situation that the adhesive paper or active paste inside the lithium-ion battery is prone to breakage or peeling, and slows down the performance degradation rate of the lithium-ion battery during actual charging and discharging.

[0037] To further explain, during the actual charging and discharging process of a lithium-ion battery, the electrochemical reaction inside the lithium-ion battery acts on the coating inside the lithium-ion battery, causing the coating to expand and stretch (such as when the lithium-ion battery is fully charged). At this time, the expansion and stretching force can be released through the channel formed by the first trench 11, so as to avoid the expansion and stretching force damaging the adhesive or active coating inside the lithium-ion battery, reducing the probability of cracking of the coating inside the lithium-ion battery, and improving the safety and energy density retention rate of the lithium-ion battery during the actual charging and discharging process (that is, slowing down the performance degradation rate).

[0038] For example, the first groove 11 can be understood as a print or crease on the surface of the current collector 10. Users can make adaptive adjustments to the pattern of the print or crease according to their needs (such as stripes, grids, etc.), and this application does not limit this. As for the protective layer 40, it can be understood as adhesive paper disposed on the battery electrode.

[0039] Optionally, the depth of the first groove 11 is less than the thickness of the current collector 10.

[0040] As described above, by utilizing the above settings, users can adaptively adjust the depth of the first trench 11 during the application of the battery electrode to meet the different requirements of the depth of the first trench 11 in different scenarios, thereby improving the applicability of the battery electrode.

[0041] Optionally, the active coating 20 is provided with a second groove 30, and the protective layer 40 covers the second groove 30.

[0042] like Figure 2 and Figure 3 As shown, the second trench 30 and the protective layer 40 are combined to form a channel for electrolyte flow on the active coating 20, allowing the electrolyte that was originally separated by the battery electrodes to flow to each other, avoiding the accumulation and continuous reaction of electrolyte inside the lithium-ion battery, improving the electrochemical stability inside the lithium-ion battery, and further slowing down the performance degradation rate of the lithium-ion battery during actual charging and discharging.

[0043] For example, before the battery electrode is wound to form a lithium-ion battery cell, the second trench 30 can be set on the active coating 20. The second trench 30 can be set by physical means (such as laser cleaning of the active coating 20, mechanical gear cleaning of the active coating 20, or scraper cleaning of the active coating 20) or by chemical means (such as cleaning the active coating 20 with chemical reagents).

[0044] It should be noted that the active coating 20 is located on at least one side of the current collector 10, and the first groove 11 is located on at least one side of the current collector 10.

[0045] For example, if the current collector 10 includes a first coating surface and a second coating surface arranged opposite to each other, the active coating 20 may be located only on the first coating surface or the second coating surface; the active coating 20 may also be located partly on the first coating surface and partly on the second coating surface; similarly, the first groove 11 may be located only on the first coating surface or the second coating surface; the first groove 11 may also be located partly on the first coating surface and partly on the second coating surface.

[0046] When the active coating 20 is provided with a second groove 30, the above arrangement can be further understood as the first groove 11 and the second groove 30 being provided on the same side of the current collector 10 or on opposite sides of the current collector 10.

[0047] Optionally, the depth of the second trench 30 is less than or equal to the thickness of the active coating 20.

[0048] As described above, the depth of the second trench 30 is less than or equal to the thickness of the active coating 20. When the depth of the second trench 30 is equal to the thickness of the active coating 20, the current collector 10 will be exposed at the bottom of the second trench 30.

[0049] In the process of applying the battery electrode, users can adaptively adjust the depth of the second trench 30 to meet the different requirements of the depth of the second trench 30 in different scenarios, thereby improving the applicability of the battery electrode.

[0050] In addition, the width of the second groove 30 is less than or equal to 15 mm, and the groove width can be understood as the distance between the two oppositely arranged groove walls of the second groove 30.

[0051] Optionally, the first trench 11 and the second trench 30 are interconnected.

[0052] like Figure 5 As shown, when the first trench 11 and the second trench 30 are disposed on the same side of the current collector 10, the above-mentioned arrangement allows the electrolyte channel formed by the first trench 11 and the electrolyte channel formed by the second trench 30 to be interconnected, thereby further facilitating the flow of electrolyte near the battery electrode and improving the flow effect of electrolyte in the above-mentioned channels.

[0053] To achieve the connection between the first trench 11 and the second trench 30, the depth of the second trench 30 and the thickness of the active coating 20 need to be equal. At this time, the projection of the second trench 30 on the current collector 10 can be adjacent to the first trench 11, or the projection of the second trench 30 on the current collector 10 can partially overlap with the first trench 11, or the first trench 11 can be located in the projection of the second trench 30 on the current collector 10.

[0054] The projection of the second groove 30 onto the current collector 10 is adjacent to the first groove 11. This can be understood as the opening at one end of the first groove 11 being located on the exposed current collector 10 at the bottom of the second groove 30. Figure 5 As shown.

[0055] The projection of the second trench 30 onto the current collector 10 partially overlaps with the first trench 11. This can be understood as the first trench 11 comprising a first sub-segment and a second sub-segment, wherein the first sub-segment is located on the exposed current collector 10 at the bottom of the second trench 30, and the second sub-segment is located on the current collector 10 covered by the active coating 20 or the protective layer 40.

[0056] The first groove 11 is located in the projection of the second groove 30 onto the current collector 10, which can be understood as the first groove 11 being disposed on the exposed current collector 10 at the bottom of the second groove 30.

[0057] Optionally, the protective layer 40 includes a first portion on the current collector 10 and a second portion on the active coating 20, the first portion covering the first trench 11 and the second portion covering the second trench 30.

[0058] As described above, by splitting the protective layer 40 to accommodate different configurations of the first groove 11 and the second groove 30, it is ensured that both the first groove 11 and the second groove 30 can be fully covered by the protective layer 40.

[0059] For example, if the first groove 11 and the second groove 30 are located on the same side of the current collector 10, then the first part and the second part of the protective layer 40 are continuous, that is, the first part is an extension of the second part, or the second part is an extension of the first part; if the first groove 11 and the second groove 30 are located on opposite sides of the current collector 10, then the first part and the second part of the protective layer 40 are independent of each other, that is, the first part and the second part of the protective layer 40 are located on opposite sides of the current collector 10, and there is no continuous relationship between them.

[0060] Optionally, the second trench 30 includes a first trench segment 31 and a second trench segment 32 extending from the first trench segment 31;

[0061] The depth of the first groove segment 31 is greater than the depth of the second groove segment 32.

[0062] like Figure 4 As shown, by utilizing the difference between the depth of the first trench 31 and the depth of the second trench 32, the mass of the active coating 20 reduced by the second trench 30 setting operation is reduced while ensuring that the effectiveness of the second trench 30 (releasing the expansion tension generated by the paste and forming a channel for the flow of electrolyte) is fully utilized, so that the battery electrode can still maintain a high energy density.

[0063] For example, when the second groove 30 is located at the edge of the active coating 20, the first groove segment 31 is located on the side of the second groove 30 away from the edge of the active coating 20, and the second groove segment 32 is located on the side of the first groove 11 close to the edge of the active coating 20. During the application of the second groove 30, the first groove segment 31 with a larger depth is used to initially release the expansion tension generated by the active coating 20, and then the second groove segment 32 with a smaller depth is used to release the expansion tension generated by the active coating 20 a second time. Under the premise of ensuring that the expansion tension is effectively released, the depth of the second groove segment 32 is reduced (the expansion tension that the second groove segment 32 needs to release is less than the expansion tension that the first groove segment 31 needs to release), thereby reducing the mass of the active coating 20 reduced by the second groove 30 setting operation.

[0064] In practical applications, the boundary between the first groove segment 31 and the second groove segment 32 can be adaptively adjusted based on the actual situation. For example, when the boundary is clear, the interior of the first groove 11 is set in a stepped manner (the part of the second groove 30 with a significant difference in depth on both sides is the boundary); or, when the boundary is unclear, the interior of the first groove 11 is set in a trapezoidal shape (the depth of the second groove 30 gradually increases or decreases along its own extension direction). This application embodiment does not limit this.

[0065] Furthermore, there are multiple first slot segments 31 and multiple second slot segments 32;

[0066] Any one of the plurality of second slot segments 32 is connected to two first slot segments 31, and the any one second slot segment 32 is located between the two first slot segments 31, and the two first slot segments 31 are adjacent.

[0067] Any one of the plurality of first slot segments 31 is connected to two second slot segments 32, and the any one first slot segment 31 is located between the two second slot segments 32, and the two second slot segments 32 are adjacent.

[0068] By adapting the number of the first groove segment 31 and the number of the second groove segment 32 as described above, the setting requirements of the second groove 30 under different scenarios can be met, thereby increasing the applicability of the battery electrode.

[0069] In practice, the depths of each part within the second groove 30 are independent of each other. Users can adjust the depth of any part of the groove within the second groove 30 according to actual needs. This application embodiment does not limit this.

[0070] Optionally, the extension direction of the second groove 30 is consistent with the length direction or width direction of the current collector 10.

[0071] like Figure 6 and Figure 7 As shown, the above settings are used to adapt to the setting requirements of the second trench 30 in different scenarios, thereby improving the applicability of the battery electrode.

[0072] It should be noted that, Figure 6 The direction indicated by the double-headed arrow is the length direction of the current collector 10. Figure 7 The direction indicated by the double-headed arrow is the width direction of the current collector 10.

[0073] Furthermore, the fact that the extension direction of the second groove 30 is consistent with the length or width direction of the current collector 10 can be understood as the extension direction of the second groove 30 being the same as the length direction of the current collector 10, or the extension direction of the second groove 30 being the same as the width direction of the current collector 10, or the extension direction of the second groove 30 not being completely the same as the length (or width) direction of the current collector 10 (e.g., the second groove 30 is inclined, the second groove 30 is corrugated, or the second groove 30 is zigzag). Users can adapt the extension direction and extension length of the second groove 30 according to their needs, and this application embodiment does not limit this.

[0074] For example, such as Figure 8 and Figure 9 As shown, the second groove 30 can be linear, striped, wavy, or grid-like.

[0075] Optionally, the extension direction of the first groove 11 is consistent with the length direction or width direction of the current collector 10.

[0076] The above settings are designed to adapt to the requirements of the first trench 11 in different scenarios, thereby improving the applicability of the battery electrode.

[0077] The description of the extension direction of the first groove 11 is similar to that of the extension direction of the second groove 30, and will not be repeated here to avoid repetition. It should be noted that the extension directions of the first groove 11 and the second groove 30 are independent of each other, that is, they can be the same or different, and the embodiments of this application do not limit this.

[0078] For example, the first groove 11 may also be linear, striped, wavy, or grid-like.

[0079] Optionally, the cross-section of the second groove 30 is polygonal, circular, elliptical or U-shaped, and / or the cross-section of the first groove 11 is polygonal, circular, elliptical or U-shaped.

[0080] As described above, users can select appropriate shapes as the cross-sections of the second groove 30 and the first groove 11 based on their needs to adapt to the setting requirements in different scenarios (the cross-sections of the second groove 30 formed by means of laser, mechanical gear, scraper, etc. are different); it should be noted that the cross-sectional shape of the first groove 11 and the cross-sectional shape of the second groove 30 are independent of each other, that is, they can be the same or different, and the embodiments of this application do not limit this.

[0081] This application also provides a battery, including the battery electrode provided in the foregoing embodiments, wherein the protective layer 40 is located at the end of the battery electrode.

[0082] The protective layer 40 being located at the end of the battery electrode can be understood as the protective layer 40 being located at the edge of the active coating 20 of the battery electrode to limit the edge of the active coating 20. At this time, a part of the protective layer 40 is bonded to the current collector 10 of the battery electrode (and covers the first trench 11), and another part of the protective layer 40 is bonded to the active coating 20 of the battery electrode (and covers the second trench 30).

[0083] This application embodiment also provides a battery, including the battery electrode sheet provided in the foregoing embodiment and the tab located on the battery electrode sheet, wherein the protective layer 40 is located on the battery electrode sheet at the position corresponding to the tab.

[0084] The protective layer 40 located at the corresponding tab position of the battery electrode can be understood as follows: the active coating of the battery electrode has a groove for receiving the tab. The tab includes a first part extending out of the battery electrode and a second part received in the groove. The protective layer 40 covers the groove and also covers the second part of the tab. For example, if the battery electrode is a positive electrode, the tab is a positive tab 60; if the battery electrode is a negative electrode, the tab is a negative tab 50.

[0085] For example, the battery also includes a cell formed by sequentially stacking a positive electrode, a separator 70, and a negative electrode and then winding them in the same direction with a winding needle as the axis.

[0086] like Figure 10As shown, when the negative electrode tab 50 is located within the groove area reserved in the negative electrode active paste of the negative electrode sheet (the groove area is not shown in the figure to highlight the position of the negative electrode tab 50), when the adhesive tape is used to fix the position of the negative electrode tab 50 on the negative electrode sheet, the second groove 30 (set on the negative electrode active paste) located near the groove area releases the expansion tension generated by the negative electrode active paste during lithium-ion charging and discharging, and forms a channel for electrolyte flow with the adhesive tape, preventing electrolyte accumulation in the negative electrode active paste portion adhered to by the adhesive tape. A second groove 30 (located on the positive electrode active paste) is also correspondingly set near the adhesive tape of the positive electrode tab 60, and its function is the same as that of the first groove 11 set on the negative electrode active paste; to avoid repetition, it will not be described again.

[0087] The aforementioned battery can be a wound lithium-ion battery or a stacked lithium-ion battery, such as a pouch battery, an aluminum-cased battery, or a cylindrical battery. This application does not limit the specific type of battery described.

[0088] The embodiments of this application have been described above with reference to the accompanying drawings. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of this application.

Claims

1. A battery electrode, characterized in that, include: Current collector, active coating, and protective layer; The active coating is disposed on the current collector, the protective layer is located on the active coating, the current collector is provided with a first groove, the protective layer covers the first groove, the active coating is provided with a second groove, and the first groove and the second groove are disposed on the same side of the current collector; The extension direction of the first groove is consistent with the length or width direction of the current collector; The protective layer covers the second trench; The first trench and the second trench are interconnected.

2. The battery electrode according to claim 1, characterized in that, The protective layer includes a first portion on the current collector and a second portion on the active coating, the first portion covering the first trench and the second portion covering the second trench.

3. The battery electrode according to claim 1, characterized in that, The second trench includes a first trench segment and a second trench segment extending from the first trench segment; The depth of the first groove segment is greater than the depth of the second groove segment.

4. The battery electrode according to claim 1, characterized in that, The extension direction of the second groove is consistent with the length or width direction of the current collector.

5. The battery electrode according to claim 1, characterized in that, The cross-section of the first trench is polygonal, circular, elliptical, or U-shaped, and / or The cross-section of the second trench is polygonal, circular, elliptical, or U-shaped.

6. The battery electrode according to claim 1, characterized in that, The depth of the first trench is less than the thickness of the current collector.

7. The battery electrode according to claim 1, characterized in that, The depth of the second trench is less than or equal to the thickness of the active coating.

8. A battery, characterized in that, The battery electrode includes any one of claims 1-7, wherein the protective layer is located at the end of the battery electrode.

9. A battery, characterized in that, The battery includes a battery electrode sheet as described in any one of claims 1-7 and a tab located on the battery electrode sheet, wherein the protective layer is located on the battery electrode sheet at a position corresponding to the tab.

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