Battery pole piece, roll core and battery

Abstract

The application provides a battery pole piece, a roll core and a battery. The battery pole piece comprises a base body, an active material layer and a polymer coating. The base body comprises a base film and a composite layer. The base film is an elastic member. The composite layer is a conductive layer. The composite layer covers the opposite two side surfaces of the base film. The active material layer is located on the outer side of the base body. Along the length direction of the base body, the outer surface of the base body has a single-side coating area coated with the active material layer on one side and a double-side coating area coated with the active material layer on both sides. The polymer coating is an elastic member and a conductive member. The polymer coating is located on the surface of the single-side coating area which is not coated with the active material layer. The application solves the problem that the pole piece is prone to breakage in the prior art.

Description

Technical Field

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

[0002] Current wound lithium-ion batteries, especially those with narrow and thick designs, experience stress concentration at corners due to electrode expansion during cycling. Ordinary adhesive cannot prevent the foil from stretching and breaking, leading to a sudden drop in capacity as the outermost positive electrode, without restraint or buffering, is prone to breakage at the junction of the single and double sides of the positive electrode and at the corners between two single sides. For silicon-doped systems, the risk of cycle breakage is even higher due to the greater expansion of the silicon anode. Furthermore, the risk of cycle breakage increases with the future increase in silicon doping. Utility Model Content

[0003] The main objective of this application is to provide a battery electrode, a winding core, and a battery to solve the problem of electrode breakage in the prior art.

[0004] To achieve the above objectives, according to one aspect of this application, a battery electrode is provided, comprising a substrate, an active material layer, and a polymer coating. The substrate includes a base film and a composite layer. The base film is an elastic element, and the composite layer is a conductive layer, with the composite layer covering opposite sides of the base film. The active material layer is located on the outer side of the substrate, and along the length of the substrate, the outer surface of the substrate has a single-sided coating area with the active material layer coated on one side and a double-sided coating area with the active material layer coated on both sides. The polymer coating is an elastic element and a conductive element, and the polymer coating is located on the surface of the single-sided coating area that is not coated with the active material layer.

[0005] Furthermore, along the length of the substrate, on the same side of the outer surface of the substrate, the polymer coating is connected to the active material layer.

[0006] Instruction manual PN317610HZYWLN

[0007] Furthermore, the active material layer and the polymer coating in the single-sided coating area are arranged so that their projections on the substrate coincide.

[0008] Furthermore, the thickness of the polymer coating is less than the thickness of the active material layer.

[0009] Furthermore, the thickness of the polymer coating is 1-10 μm.

[0010] Furthermore, the substrate is wound along its length and has a center end and a free end. The center end is located at the center of the winding, and the single-sided coating area is located at the free end.

[0011] Furthermore, along the length of the substrate, the single-sided coating area rotates at least once around the center.

[0012] Furthermore, the base film is a molten layer, the composite layer is a vapor-deposited aluminum layer, and the battery electrode is a positive electrode.

[0013] According to another aspect of this application, a core is provided, including a positive electrode sheet and a negative electrode sheet, one of which is the aforementioned battery electrode sheet. The positive electrode sheet and the negative electrode sheet are stacked and wound together along the length direction, and the polymer coating of the battery electrode sheet is located on the outermost layer of the core.

[0014] According to another aspect of this application, a battery is provided, including the aforementioned winding core.

[0015] By applying the technical solution of this application and setting the polymer coating in the single-sided coating area, the strength of the single-sided coating area of ​​the substrate can be improved. The elasticity of the polymer coating makes the single-sided coating area more deformable, thus better able to cope with the expansion and deformation of the substrate, thereby alleviating the breakage of the battery electrode during battery cycling. At the same time, it avoids the problem of battery electrode breakage caused by uneven stress between the single-sided and double-sided coating areas. On the other hand, the polymer coating in this embodiment is a conductive component, so even if the substrate breaks during battery cycling, the conductivity of the polymer coating can maintain a good conductive path after the substrate breaks, preventing a sudden drop in battery capacity after the substrate breaks. At the same time, compared with traditional adhesive paper, the polymer coating occupies less internal space in the battery, which can ensure higher energy density and safety. In addition, the base film in this embodiment also has a certain degree of elasticity, which allows the substrate to undergo elastic deformation during expansion, thereby improving the tensile strength of the substrate and making the battery electrode less prone to breakage. Attached Figure Description

[0016] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:

[0017] Figure 1 A schematic diagram of the structure of the outer surfaces on both sides of the battery electrode is shown;

[0018] Figure 2 A cross-sectional view of the battery electrode is shown;

[0019] Figure 3 A schematic diagram of the core structure is shown.

[0020] The above figures include the following reference numerals:

[0021] 10. Substrate; 11. Base membrane; 12. Composite layer; 13. Center end; 14. Free end; 20. Active material layer; 30. Polymer coating; 40. Finishing adhesive; 50. Positive tab; 60. Negative tab; 70. Positive electrode sheet; 80. Negative electrode sheet; 90. Separator. Detailed Implementation

[0022] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0023] It should be noted that, unless otherwise specified, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0024] Instruction manual PN317610HZYWLN

[0025] In this application, unless otherwise stated, directional terms such as "upper," "lower," "top," and "bottom" are generally used in relation to the direction shown in the accompanying drawings, or in relation to the vertical, perpendicular, or gravitational direction of the component itself; similarly, for ease of understanding and description, "inner" and "outer" refer to the inner and outer contours of each component itself, but the above directional terms are not intended to limit this application.

[0026] To address the problem of electrode breakage in existing technologies, this application provides a battery electrode, a winding core, and a battery.

[0027] like Figures 1 to 3 The battery electrode shown includes a substrate 10, an active material layer 20, and a polymer coating 30. The substrate 10 includes a base film 11 and a composite layer 12. The base film 11 is an elastic element, and the composite layer 12 is a conductive layer, and the composite layer 12 covers the opposite two sides of the base film 11. The active material layer 20 is located on the outside of the substrate 10. Along the length of the substrate 10, the outer surface of the substrate 10 has a single-sided coating area with the active material layer 20 coated on one side and a double-sided coating area with the active material layer 20 coated on both sides. The polymer coating 30 is an elastic element and a conductive element. The polymer coating 30 is located on the surface of the single-sided coating area that is not coated with the active material layer 20.

[0028] In this embodiment, by positioning the polymer coating 30 on one side of the coating area, the strength of the coating area on one side of the substrate 10 can be improved. The elasticity of the polymer coating 30 gives the coating area greater deformability, thus better coping with the expansion and deformation of the substrate 10, thereby mitigating the breakage of the battery electrode during battery cycling. It also avoids the problem of battery electrode breakage caused by uneven stress between the coating areas on one and both sides. Furthermore, the polymer coating 30 in this embodiment is a conductive component, ensuring that even if the substrate 10 breaks during battery cycling, the conductivity of the polymer coating 30 maintains a good conductive path after the substrate 10 breaks, preventing a sudden drop in battery capacity. Compared to traditional adhesive tape, the polymer coating 30 occupies less internal space in the battery, ensuring higher energy density and safety. In addition, the base film PN317610HZYWLN 11 in this embodiment also has a certain degree of elasticity, allowing the substrate 10 to undergo elastic deformation during expansion, thereby improving the tensile strength of the substrate 10 and making the battery electrode less prone to breakage.

[0029] In this embodiment, along the length of the substrate 10, on the same outer surface of the substrate 10, the polymer coating 30 is connected to the active material layer 20. This ensures that the battery electrode maintains continuous conductivity along its entire length. Even if the substrate 10 experiences a slight breakage, the conductivity of the polymer coating 30 can maintain the integrity of the circuit, thereby improving the battery's performance stability under extreme conditions and preventing a sudden drop in capacity caused by electrode breakage. Specifically, the substrate 10 has opposing first and second sides. The double-sided coating area, i.e., both the first and second sides, is coated with the active material layer 20, while the single-sided coating area is coated only on the first or second side. The same outer surface of the substrate 10 is either the first or second side of the substrate 10. That is, at the junction of the single-sided and double-sided coating areas, the active material layer 20 in the single-sided coating area and the polymer coating 30 in the double-sided coating area are also connected to each other to prevent excessive stress at the junction of the single-sided and double-sided coating areas from causing breakage.

[0030] like Figure 1 As shown, in this embodiment, the projections of the active material layer 20 and the polymer coating 30 on the substrate 10 in the single-sided coating area coincide, thereby ensuring that the polymer coating 30 can completely cover the part of the single-sided coating area not occupied by the active material layer 20, thereby enhancing the mechanical strength and conductivity of the area without affecting the battery energy density.

[0031] like Figure 2As shown, in this embodiment, the thickness of the polymer coating 30 is less than the thickness of the active material layer 20, thereby ensuring sufficient elasticity and conductivity throughout the battery electrode without significantly affecting the overall battery thickness and energy density. In other words, a step is formed at the junction of the active material layer 20 and the polymer coating 30, making the side of the polymer coating 30 furthest from the base film 11 closer to the base film 11 than the side of the active material layer 20 furthest from the base film 11. This improves the strength of the battery electrode without increasing its overall thickness (see specification PN317610HZYWLN), effectively addressing stress changes during cycling and reducing the risk of electrode breakage.

[0032] In this embodiment, considering the balance between coating thickness and battery performance, an excessively thin coating may not provide sufficient protection, while an excessively thick coating would occupy too much space and affect the battery's energy density. The polymer coating 30 has a thickness of 1-10 μm, thus enabling the battery to maintain good energy density and thickness distribution while significantly improving cycle performance and safety. Traditional adhesive tape used to prevent substrate 10 breakage is typically 12-20 μm thick, which has a significant impact on energy density and thickness distribution. The polymer coating 30 in this embodiment has a thinner thickness than traditional adhesive tape, thereby helping to ensure a higher energy density for the battery.

[0033] Optionally, the polymer coating 30 in this embodiment can be applied to a single-sided coating area by gravure coating of polymer monomers, followed by polymerization of the polymer monomers under a light source or heat source to form a conductive polymer coating 30 of the required thickness. Compared to traditional adhesive tape, which lacks elastic deformation and conductivity, and cannot mitigate the breakage of battery electrodes during battery cycling, and cannot maintain electronic pathways after breakage, the polymer coating 30 in this embodiment is both elastic and conductive, further mitigating the risk of battery electrode breakage during cycling. Moreover, even after the substrate 10 breaks, it can still maintain electronic conductivity, preventing a sudden drop in battery capacity.

[0034] In this embodiment, the substrate 10 is wound along its length. The substrate 10 has a center end 13 and a free end 14. The center end 13 is located at the center of the winding, and the single-sided coating area is located at the free end 14. This reduces the risk of battery electrode breakage during battery cycling by protecting the single-sided coating area with the polymer coating 30, thereby improving the battery's cycle stability and lifespan. Specifically, the substrate 10 is wound into a columnar structure, and the single-sided coating area is located on the outer ring of the columnar structure to prevent the outer battery electrode from easily breaking due to lack of restraint and buffer. Optionally, depending on the length of the single-sided coating area, it can be one turn along the winding substrate (PN317610HZYWLN 10), or half a turn, two turns, etc., ensuring that the polymer coating 30 is connected to the active material layer 20 and that the polymer coating 30 completely covers the free end 14 to prevent battery electrode breakage. Of course, depending on the actual situation, when a single-sided coating area is also provided between the center end 13 and the free end 14 of the battery electrode, the polymer coating 30 can also be located in the single-sided coating area between the center end 13 and the free end 14, which can also enhance the strength of the substrate 10 and prevent the battery electrode from breaking.

[0035] In this embodiment, the single-sided coating area rotates at least once around the winding center along the length direction of the substrate 10, thereby ensuring that the polymer coating 30 can be fully distributed at different positions along the circumference of the wound battery electrode to balance the stress distribution inside the battery and reduce the risk of battery electrode breakage caused by local stress concentration.

[0036] Compared to traditional aluminum or copper foil, the substrate 10 of this embodiment has higher tensile strength. During battery cycling, traditional aluminum or copper foil is prone to breakage at the junction of areas with single-sided and double-sided active material layer 20 coatings, and also at the corners between two areas with single-sided active material layer 20 coatings. These corners refer to the bending points during winding, i.e., locations prone to stress concentration. In this embodiment, the composite layer 12 of the substrate 10 is a vapor-deposited aluminum layer. A conductive composite layer 12 is vapor-deposited on each side of the base film 11 to form the substrate 10. The base film 11 has a certain degree of elasticity and undergoes elastic deformation during expansion, making it less prone to breakage. Furthermore, the substrate 10 of this embodiment has a lower areal density and weight compared to traditional aluminum or copper foil, resulting in higher battery energy density. Simultaneously, the substrate 10 of this embodiment also improves the pass rate against heavy impacts, thereby ensuring battery safety.

[0037] In this embodiment, the base film 11 is a molten layer, allowing it to melt rapidly when a short circuit occurs inside the battery, effectively blocking current conduction. Specifically, under normal battery cycling, the composite layer 12 is conductive, maintaining normal battery operation. When a short circuit occurs, the battery electrode temperature rises rapidly. The base film 11 located between the composite layer 12 (PN317610HZYWLN in the specification) melts rapidly under high temperature, deforming the substrate 10 and causing the composite layer 12 to break, thus quickly disconnecting the conductive path and preventing further escalation of the fault. Optionally, the base film 11 can be made of a polymer, such as PET film, i.e., high-temperature polyester film, with a melting temperature of 230-260°C. Of course, other materials can also be selected for the base film 11, ensuring sufficient elasticity and rapid melting at the required temperature.

[0038] In this embodiment, the battery electrode can be either a positive electrode 70 or a negative electrode 80. Considering that the positive electrode 70 is more prone to breakage, this embodiment will use the positive electrode 70 for explanation. Figure 3 As shown, after the base film 11 is wound and formed, the outermost battery electrode is the positive electrode 70. Therefore, the outermost edge of the positive electrode 70, away from the winding center, is not restrained and is prone to breakage. A polymer coating 30 is applied here and connected to the active material layer 20 to ensure the strength of the positive electrode 70. Of course, depending on the actual situation, this structure of the battery electrode in this embodiment can also be used on the negative electrode 80.

[0039] This embodiment also provides a wound core, including a positive electrode 70 and a negative electrode 80, one of which is the aforementioned battery electrode. The positive electrode 70 and the negative electrode 80 are stacked and wound along their length. The polymer coating 30 of the battery electrode is located on the outermost layer of the wound core. By providing the polymer coating 30 on the outermost layer of the wound core, an additional protective layer can be provided, reducing the impact of external factors on the interior of the wound core. Furthermore, in the event of a short circuit inside the battery, the polymer coating 30 can melt rapidly, effectively blocking current conduction and improving battery safety. Specifically, both the positive electrode 70 and the negative electrode 80 are wound and formed, and a separator 90 separates the positive electrode 70 and the negative electrode 80. One of the positive electrode 70 and the negative electrode 80 is located on the outermost layer of the core. The free end 14 of the positive electrode 70 or the negative electrode 80 located on the outermost layer of the core has a single-sided coating area. A polymer coating 30 is coated on the area of ​​the single-sided coating area where the active material layer 20 is not coated, so as to improve the strength of the battery electrode and thus improve the reliability of the core.

[0040] Instruction manual PN317610HZYWLN

[0041] In this embodiment, the winding core also includes a finishing adhesive for fixing the free end 14 of the substrate 10 to ensure the stability of the winding core. Preferably, the free end 14 of the substrate 10 can continue to extend a certain length along the winding direction. This extended length is called an extension section. The outer surface of the extension section is not coated with the active material layer 20 and the polymer coating 30. The finishing adhesive is used to fix the extension section to the corresponding battery electrode. That is, when the positive electrode 70 is located on the outermost layer of the winding core and the substrate 10 of the positive electrode 70 has an extension section, the finishing adhesive 40 fixes the extension section to the outermost layer of the positive electrode 70; when the negative electrode 80 is located on the outermost layer of the winding core and the substrate 10 of the negative electrode 80 has an extension section, the finishing adhesive 40 fixes the extension section to the outermost layer of the negative electrode 80.

[0042] The winding core in this embodiment also includes a positive electrode tab 50 and a negative electrode tab 60. The positive electrode tab 50 and the negative electrode tab 60 can be located in areas such as the winding center, the outermost layer of the winding core, and the middle layer of the winding core. Figure 3 As shown, in this embodiment, the positive electrode tab 50 and the negative electrode tab 60 are located at the winding center. The positive electrode tab 50 is connected to the positive electrode plate 70, and the negative electrode tab 60 is connected to the negative electrode plate 80. It should be noted that the middle layer of the core refers to the layer between the outermost layer of the core and the winding center along the winding direction.

[0043] This embodiment also provides a battery, including the aforementioned winding core.

[0044] It should be noted that "multiple" in the above embodiments refers to at least two.

[0045] As can be seen from the above description, the embodiments of this application achieve the following technical effects:

[0046] 1. This solves the problem of electrode breakage in existing technologies;

[0047] 2. By setting the polymer coating in the single-sided coating area, the strength of the single-sided coating area of ​​the substrate can be improved. The elasticity of the polymer coating makes the single-sided coating area more deformable, thus better able to cope with the expansion and deformation of the substrate, thereby alleviating the breakage of the battery electrode during the cycling process of the PN317610HZYWLN battery as specified in the manual. At the same time, it avoids the problem of battery electrode breakage caused by uneven stress between the single-sided and double-sided coating areas.

[0048] 3. The polymer coating in this embodiment is a conductive component, so that even if the substrate breaks during battery cycling, the conductivity of the polymer coating can maintain a good conductive path after the substrate breaks, preventing a sudden drop in battery capacity after the substrate breaks. At the same time, compared with traditional adhesive paper, the polymer coating occupies less internal space in the battery, which can ensure higher energy density and safety. In addition, the base film in this embodiment also has a certain degree of elasticity, which allows the substrate to undergo elastic deformation during expansion, thereby improving the tensile strength of the substrate and making the battery electrode less prone to breakage.

[0049] Obviously, the embodiments described above are merely some, not all, of the embodiments in this application. All other embodiments obtained by those skilled in the art based on the embodiments in this application without inventive effort should fall within the scope of protection of this application.

[0050] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0051] It should be noted that the terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in sequences other than those illustrated or described herein.

[0052] Instruction manual PN317610HZYWLN

[0053] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A battery electrode, characterized in that, include: The substrate (10) includes a base film (11) and a composite layer (12). The base film (11) is an elastic element, and the composite layer (12) is a conductive layer. The composite layer (12) covers the opposite two sides of the base film (11). An active material layer (20) is located on the outside of the substrate (10). Along the length of the substrate (10), the outer surface of the substrate (10) has a single-sided coating area with the active material layer (20) coated on one side and a double-sided coating area with the active material layer (20) coated on both sides. The polymer coating (30) is an elastic and conductive element located on the surface of the single-sided coating area that is not coated with the active material layer (20).

2. The battery electrode according to claim 1, characterized in that, Along the length of the substrate (10), on the same side of the outer surface of the substrate (10), the polymer coating (30) is connected to the active material layer (20).

3. The battery electrode according to claim 1, characterized in that, The active material layer (20) and the polymer coating (30) in the single-sided coating area are arranged with their projections overlapping on the substrate (10).

4. The battery electrode according to claim 1, characterized in that, The thickness of the polymer coating (30) is less than the thickness of the active material layer (20).

5. The battery electrode according to claim 1, characterized in that, The thickness of the polymer coating (30) is 1-10 μm.

6. The battery electrode according to claim 1, characterized in that, The substrate (10) is wound along its length and has a center end (13) and a free end (14). The center end (13) is located at the center of the winding and the single-sided coating area is located at the free end (14).

7. The battery electrode according to claim 6, characterized in that, Along the length of the substrate (10), the single-sided coating area rotates at least once around the center.

8. The battery electrode according to claim 1, characterized in that, The base film (11) is a molten layer, the composite layer (12) is an evaporated aluminum layer, and the battery electrode is a positive electrode (70).

9. A type of winding core, characterized in that, The battery includes a positive electrode (70) and a negative electrode (80), one of which is a battery electrode according to any one of claims 1 to 8. The positive electrode (70) and the negative electrode (80) are stacked and wound together along the length direction. The polymer coating (30) of the battery electrode is located on the outermost layer of the winding core.

10. A battery, characterized in that, Includes the core as described in claim 9.

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