Electrode sheet, winding core, battery, and method for manufacturing winding core

Abstract

The present application provides an electrode sheet, a winding core, a battery, and a method for manufacturing the winding core, and relates to the field of battery technology. The electrode sheet includes a current collector, an active material layer, and a reinforcing layer. The current collector includes an electrode tab and a body, with one side of the electrode tab connected to the body. The active material layer is attached to the body, and the reinforcing layer is attached to the end of the electrode tab closest to the body.

Description

[Technical Field]

[0001] This application claims priority to Chinese patent applications bearing application numbers 202323671291.0 and 202311874122.9, respectively, filed with the China Patent Office on December 31, 2023, the entire contents of which are incorporated herein by reference.

[0002] The present application relates to the field of battery technology, and more particularly to a pole sheet, a winding core, a battery, and a method for manufacturing the winding core. [Background technology]

[0003] In the related art, a battery cell includes a housing, and a stacked or wound arrangement of a positive electrode sheet, a separator, and a negative electrode sheet. The electrode sheet includes a current collector and an active material layer arranged on the current collector. The current collector includes a material region and a blank region located on one side of the material region. An active material layer is arranged on this material region, and no active material layer is arranged in the blank region. Typically, the blank region is used as a pole tab of the electrode sheet, and the pole tab includes a pole tab body and a pole tab root portion that connects the pole tab body to the body. Summary of the Invention [Problem to be solved by the invention]

[0004] Because the current collector is thin, the electrode tabs are prone to collapse or break at their roots during the process of winding the electrode sheet to form the winding core, reducing the reliability of the electrode sheet. Furthermore, the broken electrode tabs reduce the yield of the winding core and cause material waste. [Means for solving the problem]

[0005] The present application provides a polar sheet, a winding core, a battery, and a method for manufacturing a winding core in order to improve the problem of reduced reliability of the polar sheet.

[0006] In a first aspect, the present application provides an electrode sheet. The electrode sheet includes a current collector, an active material layer, and a reinforcing layer. The current collector includes an electrode tab and a body, and one side of the electrode tab is connected to the body. The active material layer is attached to the body. The reinforcing layer is attached to an end of the electrode tab closest to the body.

[0007] In a second aspect, the present application further provides a winding core, which includes a stacked and wound arrangement of a positive electrode sheet, a separator, and a negative electrode sheet, wherein the positive electrode sheet is the above-described electrode sheet, or both the positive electrode sheet and the negative electrode sheet are the above-described electrode sheets.

[0008] In a third aspect, the present application further provides a battery, the battery including the above-described winding core.

[0009] In a fourth aspect, the present application further provides a method for manufacturing a winding core, the method comprising obtaining and winding the pole sheet as described above, or obtaining the winding core as described above. [Effects of the Invention]

[0010] In the present invention, by providing a reinforcing layer at the end of the pole tab close to the body, the thickness of the root of the pole tab can be increased, thereby improving the strength of the root of the pole tab, which can effectively prevent the pole tab from collapsing or breaking when the pole sheet is wound, thereby improving the reliability of the pole sheet. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 2 is a schematic diagram showing the structure of a cross-section of a polar sheet provided in an example of the present application. [Figure 2] FIG. 2 is an enlarged view of part A in FIG. [Figure 3] FIG. 2 is a schematic diagram showing the positions of the reinforcing layer on side A and the reinforcing layer on side B of the electrode sheet provided in the examples of the present application. [Figure 4] FIG. 2 is a schematic diagram showing the structure of side A of the polar sheet provided in the examples of the present application. [Figure 5] FIG. 2 is a schematic diagram showing the structure of side B of the polar sheet provided in the examples of the present application. [Figure 6] FIG. 2 is a schematic diagram showing the structure of a reinforcing layer provided in an embodiment of the present application. [Figure 7] FIG. 2 is a schematic diagram showing the structure of another reinforcing layer provided in an embodiment of the present application. [Figure 8] FIG. 2 is a schematic diagram showing the structure of a winding core as viewed from a cross section of a pole sheet provided in an example of the present application. [Figure 9] FIG. 9 is an enlarged view of part C in FIG. 8. [Figure 10] 1 is a schematic diagram 1 showing the flow of manufacturing a winding core provided in an example of the present application. [Figure 11] 2 is a schematic diagram 2 showing the flow of manufacturing a winding core provided in an example of the present application. [Figure 12] 3 is a schematic diagram 3 showing the flow of manufacturing a winding core provided in an example of the present application. DETAILED DESCRIPTION OF THE INVENTION

[0012] Before describing the electrode sheet, winding core, battery, and method for manufacturing the winding core of the present application, the related art of the present application will be described.

[0013] In related technology, because the thickness of the electrode sheet current collector is thin, the electrode tabs are easily broken during the processing step of winding the electrode sheet with the electrode tabs and then manufacturing and forming the finished battery cell through various processes, resulting in a decrease in electrode sheet yield and waste of material.

[0014] For this reason, a flattening plate is usually installed to flatten the electrode sheet to prevent the electrode tab from bending, but this requires that the flattening plate be installed at different positions for different electrode sheets, making it less versatile and more likely to cause damage such as cracks to the electrode sheet when the flattening plate is used.

[0015] As the multi-pole and full-pole tab systems become more common, a means of applying an insulating layer is needed to improve the reliability of the pole sheet. However, the full-pole tab system has limitations in the application process, making it impossible to apply insulating layers of different widths. As a result, the insulating layer's ability to protect the pole sheet is limited, and the risk of pole tab breakage still exists.

[0016] Based on this, the present application provides a method for manufacturing an electrode sheet, a winding core, a battery, and a winding core in order to solve the problem of reduced reliability of the electrode sheet. In the present application, the methods for manufacturing an electrode sheet, a winding core, a battery, and a winding core are respectively described through the following examples.

[0017] Referring to FIG. 1, FIG. 1 is a schematic diagram showing the cross-sectional structure of an electrode sheet 001 provided in an embodiment of the present application. The embodiment of the present application provides an electrode sheet 001 that is applied to a winding-type winding core. The electrode sheet 001 includes a current collector 011, an active material layer 012, and a reinforcing layer 013. The current collector 011 includes an electrode tab 111 and a body 112. One side of the electrode tab 111 is connected to the body 112. The active material layer 012 is attached to the body 112. The reinforcing layer 013 is attached to the end of the electrode tab 111 that is closest to the body 112.

[0018] As can be seen, the active material layer 012 covers the body 112. The pole tab 111 includes a pole tab body and a pole tab root portion that connects the pole tab body to the body 112. The reinforcing layer 013 is located at the end of the pole tab 111 closest to the body 112, and may be located only at the pole tab root portion, or a portion may be located at the pole tab root portion and another portion may be located at the pole tab body 112.

[0019] The reinforcing layer 013 is used to reinforce the strength of the end of the pole tab 111 that is close to the body 112. The reinforcing layer 013 also has insulating properties. The reinforcing layer 013 may include, but is not limited to, an insulating layer and an adhesive layer.

[0020] In this embodiment, by providing a reinforcing layer 013 at the end of the electrode tab 111 closest to the body 112, the thickness of the root of the electrode tab can be increased, thereby improving the strength of the root of the electrode tab. This effectively prevents the electrode tab from collapsing or breaking when the electrode sheet 001 is wound, thereby improving the reliability of the electrode sheet. In this way, the yield of winding-type winding cores using this electrode sheet 001 can be improved, and the manufacturing cost of winding-type winding cores can be reduced.

[0021] The reinforcing layer 013 may be made of a material having a strength greater than that of the current collector 011 so that the reinforcing layer 013 can improve the strength of the root portion of the electrode tab with a relatively small thickness.

[0022] Referring to Figure 2, Figure 2 is an enlarged view of part A in Figure 1. In one embodiment, a winding center is defined, and the electrode sheet 001 has an A side facing the winding center and a B side away from the winding center, and a reinforcing layer 013 and an active material layer 012 are provided on both sides A and B. As shown in Figures 4 and 5, Figure 4 is a schematic diagram showing the structure of side A of the electrode sheet 001 provided in the embodiment of the present application, and Figure 5 is a schematic diagram showing the structure of side B of the electrode sheet 001 provided in the embodiment of the present application.

[0023] In this embodiment, a reinforcing layer 013 is installed on both sides of the pole tab 111, thereby simultaneously reinforcing both sides of the pole tab, thereby improving the symmetry of reinforcing on both sides of the base of the pole tab and thereby improving reliability.

[0024] 2, in one embodiment, along the width direction of the pole sheet 001, the reinforcing layer 013 on side A has a width dimension L1. The reinforcing layer 013 on side B has a width dimension L2. The pole tab 111 has a width dimension H1, where 15% H1≦L1≦50% H1 and 15% H1≦L2≦50% H1 are satisfied.

[0025] For ease of understanding, L1 and L2 may be 15%H1, 20%H1, 30%H1, 40%H1, 45%H1, 50%H1, but are not limited thereto. For example, when H1 is 6.5 mm, L1 and L2 may be 0.975 mm, 1.3 mm, 1.95 mm, 2.6 mm, 2.925 mm, 3.25 mm, but are not limited thereto.

[0026] Also, L1 may be equal to L2 or not equal to L2. When L1 is equal to L2, the reinforcing layer 013 on the A side and the reinforcing layer 013 on the B side may be installed in an aligned state on both sides of the tab or may be offset from each other. When L1 is not equal to L2, in the width direction of the electrode sheet 001, one end face of the reinforcing layer 013 on the A side may be flush with one end face of the reinforcing layer 013 on the B side.

[0027] In this embodiment, by limiting L1 and L2 as described above, it is possible to avoid the situation where the dimensions of L1 and L2 are too small to support the tab, and on the other hand, it is possible to avoid the situation where the values of L1 and L2 are too large to be disadvantageous for winding and electrical connection with the bus bar.

[0028] In one embodiment, L1 < L2 and 30%H1 ≤ L2 ≤ 50%H1 are satisfied.

[0029] Exemplarily, 50%L2 ≤ L1 ≤ 90%L2.

[0030] For ease of understanding, L1 may be 50%L2, 60%L2, 70%L2, 80%L2, 86%L2, 90%L2, but is not limited thereto. For example, when L2 is 2.5 mm, L1 may be 1.25 mm, 1.5 mm, 1.75 mm, 2 mm, 2.15 mm, 2.25 mm, but is not limited thereto.

[0031] Accordingly, in combination with the previous embodiment, 15%H1≦L1≦45%H1 and 30%H1≦L2≦50%H1. Here, L1 may be, but is not limited to, 15%H1, 20%H1, 30%H1, 40%H1, or 45%H1. L2 may be, but is not limited to, 30%H1, 36%H1, 38%H1, 40%H1, 45%H1, or 50%H1. For example, if H1 is 6.5 mm, L1 may be, but is not limited to, 0.975 mm, 1.3 mm, 1.95 mm, 2.6 mm, or 2.925 mm, and L2 may be, but is not limited to, 1.95 mm, 2.34 mm, 2.47 mm, 2.6 mm, 2.925 mm, or 3.25 mm.

[0032] As can be seen, because side A is located toward the winding center, side A is in a state of compression when the polar sheet 001 is wound. Because side B is located away from the winding center, side B is in a state of tension when the polar sheet 001 is wound. For this reason, in this embodiment, by making the width dimension L1 of the reinforcing layer 013 on side A smaller than the width dimension L2 of the reinforcing layer 013 on side B, the connection surface area between side A and the reinforcing layer 013 becomes relatively small. As a result, when the polar sheet 001 is wound, the reinforcing layer 013 on side A does not hinder the bending of the polar sheet 001, and the polar sheet 001 can be wound more smoothly.

[0033] Referring to FIG. 2, in one embodiment, along the thickness direction of the pole sheet 001, the reinforcing layer 013 on the A side has a thickness dimension D1, and the reinforcing layer 013 on the B side has a thickness dimension D2, where D1>D2.

[0034] Illustratively, 40% D1≦D2≦80% D1.

[0035] As can be appreciated, D2 may be, but is not limited to, 40% D1, 50% D1, 60% D1, 70% D1, 75% D1, 80% D1, etc. For example, if D1 is 0.05 mm, D0 may be, but is not limited to, 0.02 mm, 0.025 mm, 0.03 mm, 0.035 mm, 0.04 mm.

[0036] Because L1 is smaller than L2, the supporting effect of the reinforcing layer 013 on the A side on the pole tab is weaker than the strengthening effect of the reinforcing layer 013 on the B side on the pole tab. Based on this, in this embodiment, the thickness D1 of the reinforcing layer 013 on the A side is made larger than the thickness D2 of the reinforcing layer 013 on the B side, thereby increasing the thickness of the reinforcing layer 013 on the A side, thereby improving the strengthening effect of the reinforcing layer 013 on the A side on the pole tab, and ultimately realizing stable support of the root portion of the pole tab by the reinforcing layer 013 on the A side.

[0037] In one embodiment, the electrode sheet 001 is a positive electrode sheet, and the side of the reinforcing layer 013 on the A side, away from the active material layer 012 on the A side, is flush with the side of the reinforcing layer 013 on the B side, away from the active material layer 012 on the B side. As shown in Figure 3, Figure 3 is a schematic diagram showing the positions of the reinforcing layer 013 on the A side and the reinforcing layer 013 on the B side of the electrode sheet 001 provided in the embodiment of the present application.

[0038] In this embodiment, the above-mentioned installation allows the reinforcing layers 013 on sides A and B of the pole sheet 001 to share a single positioning reference, thereby improving the convenience of installation of the reinforcing layers 013 and ultimately increasing the manufacturing efficiency of the pole sheet 001.

[0039] 3, in one embodiment, on the A side, the reinforcing layer 013 and the edge of the body 112 are spaced apart, and the distance between the reinforcing layer 013 and the edge of the body 112 is L4. On the B side, the reinforcing layer 013 and the edge of the body 112 are spaced apart, and the distance between the reinforcing layer 013 and the edge of the body 112 is L5, where L4>L5.

[0040] In this embodiment, due to the above limitation, the distance between the reinforcing layer 013 on the A side of the electrode sheet 001 and the edge of the main body 112 is made larger than the distance between the reinforcing layer 013 on the B side of the electrode sheet 001 and the edge of the main body 112. As a result, the support of the A side of the electrode tab by the reinforcing layer 013 on the A side becomes weaker than the support of the B side of the electrode tab by the reinforcing layer 013 on the B side. When the electrode sheet 001 is wound, the electrode tab is more easily bent toward the center of the winding core, realizing a directional bending of the electrode tab, and thus contributing to the subsequent connection between the electrode tab and the bus bar.

[0041] Referring to FIG. 2, in one embodiment, along the width direction of the electrode sheet 001, the reinforcing layer 013 on the A side has a width dimension L1, satisfying 15%L1≦L4≦27%L1.

[0042] Exemplarily, 0.25mm≦L5<L4≦1.5mm, for example, L4 = 0.7mm, L5 = 0.5mm, or L4 = 0.5mm, L5 = 0.3mm, or L4 = 0.38mm, L5 = 0.2mm.

[0043] In this embodiment, by limiting the distance L4 between the reinforcing layer 013 on the A side and the edge of the main body 112, it is possible to avoid the distance between the reinforcing layer 013 and the edge of the main body 112 being too small, and to avoid the active material layer 012 and the reinforcing layer 013 in the compressed state on the A side interfering with each other due to deformation. On the other hand, it is possible to avoid the distance between the reinforcing layer 013 and the edge of the main body 112 being too large and unable to strengthen the root of the electrode tab.

[0044] Also, by limiting the minimum value of L4, the minimum value of the distance between the reinforcing layer 013 on the A side and the edge of the main body 112 is limited, ensuring that the electrode sheet has directionality when wound, and thus improving the smoothness of winding.

[0045] 2, in one embodiment, along the thickness direction of the electrode sheet 001, the electrode sheet 001 has a thickness dimension D4 at the active material layer 012. The electrode sheet 001 has a thickness dimension D0 at the reinforcing layer 013, and 50% D4≦D0≦90% D4 is satisfied.

[0046] As can be understood, in this field, the distance along the thickness direction of the electrode sheet 001 between the surface of the active material layer 012 located on one side of the current collector 011 and the surface of the active material layer 012 located on the other side of the current collector 011 is the thickness dimension D4 of the active material layer 012 of the electrode sheet 001. In addition, the distance between the surface of the reinforcing layer 013 located on one side of the current collector 011 and the surface of the reinforcing layer 013 located on the other side of the current collector 011 is the thickness dimension D0 of the reinforcing layer 013 of the electrode sheet 001.

[0047] Here, D0 may be, but is not limited to, 50% D4, 60% D4, 70% D4, 80% D4, or 90% D4. For example, if D4 is 0.124 mm, D0 may be, but is not limited to, 0.062 mm, 0.08 mm, 0.09 mm, 0.10 mm, or 0.116 mm.

[0048] In one embodiment, the reinforcing layer 013 includes a first adhesive layer 131 attached to the polar tab 111. Specifically, the first adhesive layer 131 may be a thermosetting adhesive, a UV-curable adhesive, or a mixture of a UV-curable adhesive and an insulating filler.

[0049] As can be understood, the thermosetting adhesive is a thermosetting resin, and the thermosetting resin may be at least one of phenolic resin, urea-formaldehyde resin, melamine-formaldehyde resin, epoxy resin, organic silicone resin, polyurethane, and polyimide. The UV-curable adhesive is a UV-curable resin. The UV-curable resin may be at least one of epoxy acrylate, polyacrylate, polyester acrylate, acrylonitrile-functional acrylate, and silicone / fluorine light-curable resin. Thermosetting adhesives and UV-curable adhesives typically have a fast curing time, allowing the reinforcing layer 013 to cure quickly and be strongly bonded to the pole tab. This reduces the waiting time for adhesive curing and ultimately improves manufacturing efficiency.

[0050] In this embodiment, by using the above adhesive, the electrode tabs of the electrode sheet 001 are pre-folded during winding, and the reinforcing layer 013 is hardened, improving the support effect of the reinforcing layer 013 for the electrode tabs. This effectively prevents the electrode tabs from collapsing or breaking, thereby improving the yield of wound components and reducing the manufacturing costs of wound components. Meanwhile, the first adhesive layer 131 has a fast hardening time, allowing the first adhesive layer 131 to harden rapidly and firmly adhere to the electrode tabs. This makes the process of connecting the hardening layer to the electrode tabs more convenient, shortens the time required for hardening the first adhesive layer 131, and improves manufacturing efficiency.

[0051] 6, which is a schematic diagram showing the structure of the reinforcing layer 013 provided in an embodiment of the present application. In one embodiment, the reinforcing layer 013 further includes an expansion layer 132, which is disposed on the side of the first adhesive layer 131 away from the polar tab 111.

[0052] As can be seen, the intumescent layer 132 is an intumescent adhesive tape.

[0053] In this embodiment, when the battery cell is assembled and filled with electrolyte, the expansion layer 132 expands to fill the gap at the edges between the positive electrode sheet 002 and the negative electrode sheet 004. In this way, not only are the positive electrode sheet 002 and the negative electrode sheet 004 insulated and separated, but the edges of the electrode tabs and the separator 003 are firmly pressed together, integrating them, increasing the vibration resistance of the electrode tabs and reducing the vibration amplitude of the electrode tabs upon impact, thereby effectively reducing the possibility of internal short circuits due to external impact and thereby improving the safety and reliability of the battery.

[0054] Referring to FIG. 7, FIG. 7 is a schematic diagram showing the structure of another reinforcing layer 013 provided in an embodiment of the present application. In one embodiment, the reinforcing layer 013 includes a first adhesive layer 131, an expansion layer 132, a second adhesive layer 134, and a PI (Polyimide) layer 135, which are sequentially disposed along a direction away from the pole tab. The PI layer 135 is disposed on the side of the expansion layer 132 away from the first adhesive layer 131 by the second adhesive layer 134. The second adhesive layer 134 may be, but is not limited to, a UV-curable resin or an acrylic adhesive. Specifically, the second adhesive layer 134 may be a thermosetting adhesive, a UV-curable adhesive, or a mixture of a UV-curable adhesive and an insulating filler.

[0055] In this embodiment, the above-described installation improves the insulating performance of the reinforcing layer 013, thereby improving reliability. On the other hand, the strength of the reinforcing layer 013 is improved, which prevents the reinforcing layer 013 from being damaged by burrs on the pole tab portion.

[0056] In one embodiment, one 4680 cylindrical battery cell and electrode sheet 001 are used as the positive electrode sheet, and the relevant dimensions and values ​​are as follows:

[0057] [Table 1]

[0058] In Table 1, the cut width L3 of the polar tab on side A = width H1 of the polar tab 111 - width L1 of the reinforcing layer 013 on side A - distance L4 between the reinforcing layer 013 on side A and the edge of the main body 112. The cut width L3 of the polar tab on side B = width H1 of the polar tab 111 - width L2 of the reinforcing layer 013 on side B - distance L5 between the reinforcing layer 013 on side B and the edge of the main body 112.

[0059] The cut width of the pole tab in Table 1 refers to the cut dimensions of the pole tab formed by cutting the blank area of ​​the current collector.

[0060] Accordingly, the present embodiment further provides a winding core, which includes a wound positive electrode sheet 002, a separator 003, and a negative electrode sheet 004, wherein the positive electrode sheet 002 is the electrode sheet 001 disclosed in some embodiments of the present application, or the positive electrode sheet 002 and the negative electrode sheet 004 are both the electrode sheets 001 disclosed in some embodiments of the present application.

[0061] As can be understood, from the viewpoint of battery design, the negative electrode sheet 004 should completely surround the positive electrode sheet 002. To avoid bending of the electrode tabs of the positive electrode sheet 002, the structure of at least the positive electrode sheet 002 should be the structure of the electrode sheet 001 disclosed in some embodiments of the present application.

[0062] In this embodiment, the electrode sheet 001 disclosed in some embodiments of the present application is used as the positive electrode sheet 002 of the winding core, thereby increasing the thickness dimension of the root portion of the electrode tab and increasing the strength of the root portion of the electrode tab.As a result, when the positive electrode sheet 002 is wound, the electrode tab of the positive electrode sheet 002 prevents bending at the root portion of the electrode tab, avoiding breakage of the electrode tab, thereby improving the yield of the winding core and reducing the manufacturing cost of the winding core.

[0063] 8 and 9, FIG. 8 is a schematic diagram showing the structure of a winding core as seen from a cross section of an electrode sheet 001 provided in an example of the present application, and FIG. 9 is an enlarged view of portion C in FIG. 8. In one example, the winding core has a winding center, and the surface of the positive electrode sheet 002 facing the winding center is surface A. Along the width direction of the positive electrode sheet 002, the reinforcing layer 013 on surface A has a first end face facing the active material layer 012 on surface A and a second end face away from the active material layer 012 on surface A. A plane parallel to the winding center is defined as the projection plane, and a direction perpendicular to the projection plane is defined as the projection direction. On the projection plane, the orthogonal projection of the edge of the negative electrode sheet 004 is located between the orthogonal projection of the first end face and the orthogonal projection of the second end face.

[0064] In FIG. 9, the dimension of the edge of the negative electrode sheet 004 that protrudes from the edge of the body 112 of the positive electrode sheet 002 is H3, and the distance between the first end face and the edge of the body 112 of the positive electrode sheet 002 is L4. <H3である。

[0065] Illustratively, L4 is 0.7 mm and H3 is 1 mm.

[0066] In this embodiment, due to the above limitations, the reinforcing layer 013 protects the electrode tab of the positive electrode sheet 002 from bending, and also prevents the edge of the negative electrode sheet 004 from getting caught between the first end face and the edge of the main body 112 of the positive electrode sheet 002, which could lead to a short circuit, thereby improving the reliability of the winding core.

[0067] Referring to FIG. 9, in one embodiment, the orthogonal projection of the edge of the separator 003 is between the orthogonal projection of the second end surface and the orthogonal projection of the edge of the main body 112 of the negative electrode sheet 004 on the projection plane.

[0068] As can be understood, the pole tabs of the positive electrode sheet 002 and the pole tabs of the negative electrode sheet 004 are respectively located at both ends of the winding center. The edge of the pole sheet of the negative electrode sheet 004 close to the pole tab of the positive electrode sheet 002 is the edge of the main body of the negative electrode sheet 004. Therefore, by installing the gap between the second end face and the edge of the main body 112 of the negative electrode sheet 004 opposite to the edge of the separator 003, insulation isolation between the negative electrode sheet 004 and the positive electrode sheet 002 can be achieved.

[0069] Here, the surface of the positive electrode sheet 002 away from the winding center is the B surface. On the B surface, as shown in FIG. 9, along the width direction of the positive electrode sheet 002, the distance between the second end face and the edge of the main body 112 of the positive electrode sheet 002 = the width dimension L2 of the strengthening layer 013 on the B surface + the distance L5 between the strengthening layer 013 on the B surface and the edge of the main body 112 on the B surface. Along the width direction of the positive electrode sheet 002, the dimension by which the edge of the separator 003 protrudes from the edge of the main body 112 of the positive electrode sheet 002 is H2. Also, the orthographic projection of the edge of the separator 003 described above is between the orthographic projection of the second end face and the orthographic projection of the edge of the main body 112 of the negative electrode sheet 004, and correspondingly, L5 < H2 < L5 + L2.

[0070] Exemplarily, L5 is 0.3 mm, L2 is 2.5 mm, and correspondingly, 0.3 mm < H2 < 2.8 mm. For example, H2 = 2 mm.

[0071] In this embodiment, due to the above limitations, by installing the edge of the separator 003 opposite to the strengthening layer 013, in the wound core, the gap between the pole tab of the positive electrode sheet 002, the edge of the separator 003, and the edge of the negative electrode sheet 004 can be filled by the strengthening layer 013, integrating the edges of these three components, and thus improving the structural stability of the core.

[0072] Furthermore, if the reinforcing layer 013 includes an expansion layer, when the battery cell is assembled and filled with electrolyte, the expansion layer expands to fill the gap between the electrode tab of the positive electrode sheet 002 and the edge of the negative electrode sheet 004, compressing and integrating the edges of the separator 003, the edge of the negative electrode sheet 004, the electrode tab of the positive electrode sheet 002, and the expansion layer 132. In this way, not only are the positive electrode sheet 002 and the negative electrode sheet 004 insulated and isolated from each other, but the electrode tab of the positive electrode sheet 002, the edge of the negative electrode sheet 004, and the edge of the separator 003 are firmly pressed together and integrated, increasing the vibration resistance of the electrode tab portions and reducing the amplitude of vibration between them upon impact, thereby effectively reducing the possibility of internal short circuits due to external impact and thereby improving the safety and reliability of the battery.

[0073] Accordingly, embodiments of the present application further provide a battery, the battery including a wound core as disclosed in some embodiments of the present application.

[0074] As can be seen, the battery includes a battery box and a battery cell housing disposed within the battery box, the winding core disposed within the battery cell housing, and the battery cell housing filled with an electrolyte.

[0075] In this embodiment, by using the winding cores disclosed in some of the embodiments of the present application, it is possible to improve the yield of batteries and, in turn, reduce the manufacturing costs of batteries.

[0076] Accordingly, embodiments of the present application further provide a method for manufacturing a winding core, which method includes obtaining and winding a pole sheet 001 disclosed in some embodiments of the present application, or obtaining a winding core disclosed in some embodiments of the present application.

[0077] In this embodiment, by using the pole sheet 001 or winding core disclosed in some embodiments of the present application, the pole tab 111 of the pole sheet 001 can be prevented from collapsing or breaking during winding, thereby improving the yield of wound components and reducing the manufacturing costs of wound components.

[0078] In one embodiment, the reinforcing layer 013 includes a first adhesive layer 131 attached to the polar sheet 001, which is applied in the following manner: the first adhesive layer 131 is attached to the end of the polar tab 111 of the polar sheet 001 that is close to the body 112, and the polar tab 111 of the polar sheet 001 is pre-folded during winding, and the first adhesive layer 131 on the pre-folded polar tab 111 of the polar sheet 001 is subjected to a curing treatment.

[0079] For example, the first adhesive layer 131 may be a thermosetting adhesive, a UV-curable adhesive, or a mixture of a UV-curable adhesive and an insulating filler, where the insulating filler may be ceramic powder.

[0080] In this way, the electrode tab of the positive electrode sheet 002 is bent and formed in a predetermined direction, thereby improving the strength of the electrode tab and preventing the electrode tab of the positive electrode sheet 002 from collapsing or breaking.

[0081] Here, if the first adhesive layer 131 is a thermosetting adhesive, the reinforcing layer 013 is heated to harden the reinforcing layer 013. If the first adhesive layer 131 is a UV-curable adhesive or a mixture of a UV-curable adhesive and an insulating filler, the reinforcing layer 013 is hardened by irradiating it with ultraviolet light using a UV curing device.

[0082] In one embodiment, the method further comprises baking the reinforcing layer 013 before pre-folding the pole tabs 111 of the pole sheet 001 .

[0083] In this embodiment, the reinforcing layer 013 is baked to initially harden the reinforcing layer, thereby controlling the adhesion of the reinforcing layer 013 and preventing random adhesion of the reinforcing layer 013 to other components, thereby contributing to smoother manufacturing of the winding core.

[0084] In one embodiment, the reinforcing layer 013 further includes an expansion layer 132, and after applying the first adhesive layer 131 to the end of the polar tab 111 of the polar sheet 001 closer to the main body 112, the method further includes applying the expansion layer 132 to the side of the first adhesive layer 131 away from the polar tab 111.

[0085] In this embodiment, the expansion layer 132 is provided so that, when the battery cell is assembled and filled, the expansion layer expands to fill the gap between the electrode tab of the positive electrode sheet 002 and the edge of the negative electrode sheet 004, compressing and integrating the edges of the separator 003, the edges of the negative electrode sheet 004, the electrode tab of the positive electrode sheet 002, and the expansion layer 132. In this way, not only are the positive electrode sheet 002 and the negative electrode sheet 004 insulated and isolated from each other, but the electrode tab of the positive electrode sheet 002, the edge of the negative electrode sheet 004, and the edge of the separator 003 are firmly pressed together and integrated, increasing the vibration resistance of the electrode tabs and reducing the swing amplitude between them upon impact, thereby effectively reducing the possibility of internal short circuits due to external impact and thereby improving the safety and reliability of the battery.

[0086] In one embodiment, the reinforcing layer 013 further includes a second adhesive layer 134 and a PI layer 135. After applying the expansion layer 132 to the first adhesive layer 131 on the side remote from the polar tab 111, the method further includes applying a second adhesive layer 134 to the expansion layer 132 on the side remote from the first adhesive layer 131 and applying a PI layer 135 to the second adhesive layer 134 on the side remote from the expansion layer 132.

[0087] In this embodiment, the above-described installation improves the insulating performance of the reinforcing layer 013, thereby improving reliability. On the other hand, the strength of the reinforcing layer 013 is improved, which prevents the reinforcing layer 013 from being damaged by burrs on the pole tab portion.

[0088] In one embodiment, the method further includes manufacturing and baking a reinforcing layer 013, placing the baked reinforcing layer 013 on an end of a pole tab 111 of a pole sheet 001 that is close to the body 112, pre-folding the pole tab 111 of the pole sheet 001 during winding, and performing a curing treatment on the reinforcing layer 013 on the pre-folded pole tab 111.

[0089] Here, the reinforcing layer 013 includes a first adhesive layer 131, an expansion layer 132, a second adhesive layer 134, and a PI layer 135, which are laminated in this order.

[0090] In this embodiment, by installing the reinforcing layer 013 on the electrode tab 111 of the electrode sheet 001 after manufacturing is completed, the manufacturing of the reinforcing layer 013 and the application of the active material layer on the current collector 011 can be performed separately, thereby improving the manufacturing efficiency of the electrode sheet 001.

[0091] Based on the above example, the manufacturing of the winding core will be described as follows.

[0092] (1) When the reinforcing layer 013 includes a first adhesive layer 131, and the first adhesive layer 131 is a mixture of a UV-curable adhesive and an insulating filler, as shown in FIG. 10, which is a schematic diagram 1 showing the flow of manufacturing a winding core provided in an embodiment of the present application, and the manufacturing method of the winding core includes the following steps:

[0093] In step S100, an adhesive is produced by mixing a UV-curable adhesive and an insulating filler.

[0094] In step S200, the positive electrode sheet 002 is manufactured. Specifically, an electrode sheet body is obtained, an adhesive is applied to the root portion of the electrode tab of the electrode sheet body, and the adhesive is dried to form a reinforcing layer 013, i.e., a first adhesive layer 131. As can be understood, if the reinforcing layer 013 includes only the first adhesive layer 131, drying the reinforcing layer 013 is equivalent to drying the first adhesive layer 131.

[0095] In step S300, a winding core is formed. Specifically, the positive electrode sheet 002 is wound, and during the winding, the electrode tab of the positive electrode sheet 002 is pre-folded, and the reinforcing layer 013 on the pre-folded electrode tab of the positive electrode sheet 002 is cured by a UV curing device.

[0096] (2) When the reinforcing layer 013 includes a first adhesive layer 131 and an expansion layer 132, and the first adhesive layer 131 is a mixture of a UV-curable adhesive and an insulating filler, as shown in FIG. 11, which is a schematic diagram 2 showing the flow of manufacturing the winding core provided in the examples of the present application, and the manufacturing method of the winding core includes the following steps:

[0097] In step S100, an adhesive is produced by mixing a UV-curable adhesive and an insulating filler.

[0098] In step S200, the positive electrode sheet 002 is manufactured. Specifically, an electrode sheet body is obtained, an adhesive is applied to the root of the electrode tab of the electrode sheet body, and the adhesive is dried to form a first adhesive layer 131.

[0099] In step S300, the expansion layer 132 is applied to the first adhesive layer 131 to form the reinforcement layer 013.

[0100] In step S400, a winding core is formed. Specifically, the positive electrode sheet 002 is wound, and during the winding, the electrode tab of the positive electrode sheet 002 is pre-folded, and the reinforcing layer 013 on the pre-folded electrode tab of the positive electrode sheet 002 is cured by a UV curing device.

[0101] (3) When the reinforcement layer 013 includes a first adhesive layer 131, an expansion layer 132, a second adhesive layer 134, and a PI layer 135, and the first adhesive layer 131 is a mixture of a UV-curable adhesive and an insulating filler, as shown in FIG. 12. FIG. 12 is a schematic diagram 3 showing the flow of manufacturing the winding core provided in the examples of the present application, and the manufacturing method of the winding core includes the following steps:

[0102] In step S100, an adhesive tape is manufactured. Specifically, a mixture of a UV-curable adhesive and an insulating filler is applied to two surfaces of an expansion layer 132 to form a first adhesive layer 131 and a second adhesive layer 134, respectively. Then, a PI layer 135 is placed on the side of the second adhesive layer 134 away from the expansion layer 132, and then the tape is baked to obtain a reinforcement layer 013.

[0103] In step S200, the positive electrode sheet 002 is manufactured. Specifically, the positive electrode sheet body is obtained, and the reinforcing layer 013 is attached to the root of the electrode tab of the positive electrode sheet body.

[0104] In step S300, a winding core is formed. Specifically, the positive electrode sheet 002 is wound, and during the winding, the electrode tab of the positive electrode sheet 002 is pre-folded, and the reinforcing layer 013 on the pre-folded electrode tab of the positive electrode sheet 002 is cured by a UV curing device. [Explanation of symbols]

[0105] 001: Extreme Sheet 011: Current collector 111: Polar tab 112:Main body 012: Active material layer 013: Reinforcement layer 131: First adhesive layer 132: Expansion layer 134: Second adhesive layer 135:PI layer 002: Positive electrode sheet 003: Separator 004: Negative electrode sheet

Claims

1. a current collector (011) including a pole tab (111) and a body (112), one side of the pole tab (111) being connected to the body (112); An active material layer (012) disposed on the main body (112); a reinforcing layer (013) disposed at the end of the pole tab (111) closest to the body (112);

2. The electrode sheet (001) according to claim 1, wherein a winding center is determined, the electrode sheet (001) includes an A-side surface facing the winding center and a B-side surface away from the winding center, and the A-side surface and the B-side surface are both provided with the reinforcing layer (013) and the active material layer (012).

3. Along the width direction of the pole sheet (001), the reinforcing layer (013) of the A side has a width dimension L １ The reinforcing layer (013) on the B side has a width dimension L ２ and the pole tab (111) has a width dimension H １ and 15% H １ ≦L １ ≦50%H １ , 15%H １ ≦L ２ ≦50%H １ The polar sheet (001) according to claim 2, which satisfies the above.

4. L １ <L ２ The polar sheet (001) according to claim 3,

5. 50% L ２ ≦L １ ≦90%L ２ The polar sheet (001) according to claim 4,

6. 15% H １ ≦L １ ≦45%H １ The polar sheet (001) according to claim 5,

7. Along the thickness direction of the pole sheet (001), the reinforcing layer (013) of the A side has a thickness dimension D １ The reinforcing layer (013) on the B side has a thickness dimension D ２ and D １ >D ２ The polar sheet (001) according to any one of claims 4 to 6, which satisfies the above.

8. The electrode sheet (001) is a positive electrode sheet (002), 30% H １ ≦L ２ ≦50%H １ 8. The polar sheet (001) according to any one of claims 4 to 7,

9. The electrode sheet (001) according to any one of claims 4 to 8, wherein the side of the reinforcing layer (013) on the A side away from the active material layer (012) on the A side is on the same plane as the side of the reinforcing layer (013) on the B side away from the active material layer (012) on the B side.

10. On the surface A, the reinforcing layer (013) and the edge of the main body (112) are spaced apart, and the distance between the reinforcing layer (013) and the edge of the main body (112) is L ４ and On the surface B, the reinforcing layer (013) and the edge of the main body (112) are spaced apart, and the distance between the reinforcing layer (013) and the edge of the main body (112) is L ５ and L ４ >L ５ The polar sheet (001) according to any one of claims 2 to 9, which satisfies the above.

11. Along the width direction of the pole sheet (001), the reinforcing layer (013) of the A side has a width dimension L １ and 15% L １ ≦L ４ ≦27%L １ The polar sheet (001) according to claim 10, which satisfies the above.

12. 0.25 mm≦L ５ <L ４ 12. The polar sheet (001) according to claim 11, wherein the thickness is ≦1.5 mm.

13. Along the thickness direction of the electrode sheet (001), the electrode sheet (001) has a thickness dimension D ４ In the reinforcing layer (013), a thickness dimension D ０ and 50% D ４ ≦D ０ ≦90%D ４ The polar sheet (001) according to any one of claims 1 to 12, which satisfies the above.

14. 14. The polar sheet (001) according to any one of claims 1 to 13, wherein the reinforcing layer (013) comprises a first adhesive layer (131) applied to the polar tab (111).

15. The reinforcing layer (013) further comprises an intumescent layer (132), 15. The polar sheet (001) according to claim 14, wherein the expansion layer (132) is disposed on the side of the first adhesive layer (131) away from the polar tab (111).

16. The reinforcing layer (013) comprises a second adhesive layer (134) and a PI layer (135); The polar sheet (001) of claim 15, wherein the PI layer (135) is attached to the side of the expansion layer (132) away from the first adhesive layer (131) by the second adhesive layer (134).

17. The polar sheet (001) according to claim 16, wherein the first adhesive layer (131) and / or the second adhesive layer (134) is a thermosetting adhesive, a UV curable adhesive, or a mixture of a UV curable adhesive and an insulating filler.

18. The battery includes a wound cathode sheet (002), a separator (003), and an anode sheet (004), The positive electrode sheet (002) is the electrode sheet (001) according to any one of claims 1 to 17, or A winding core, wherein the positive electrode sheet (002) and the negative electrode sheet (004) are both the electrode sheet (001) according to any one of claims 1 to 17.

19. 19. The winding core according to claim 18, wherein a winding center is defined, a surface of the positive electrode sheet (002) facing the winding center is surface A, and along the width direction of the positive electrode sheet (002), the reinforcing layer (013) of surface A includes a first end face facing the active material layer (012) of surface A and a second end face away from the active material layer (012) of surface A, a plane parallel to the winding center is defined as a projection plane, a direction perpendicular to the projection plane is defined as a projection direction, and on the projection plane, an orthogonal projection of an edge of the main body (112) of the negative electrode sheet (004) is located between the orthogonal projection of the first end face and the orthogonal projection of the second end face.

20. 20. The winding core according to claim 19, wherein, in the projection plane, the orthogonal projection of the edge of the separator (003) is between the orthogonal projection of the second end surface and the orthogonal projection of the edge of the main body (112) of the negative electrode sheet (004).

21. A battery comprising the winding core according to any one of claims 18 to 20.

22. Obtaining and winding a pole sheet (001) according to any one of claims 1 to 17, or A method for manufacturing a winding core, comprising obtaining a winding core according to any one of claims 18 to 20.

23. The reinforcing layer (013) comprises a first adhesive layer (131), The method comprises: Before winding the polar sheet (001), the first adhesive layer (131) is applied to the end of the polar tab (111) of the polar sheet (001) that is close to the body (112); 23. The method for manufacturing a winding core according to claim 22, further comprising: pre-folding the pole tab (111) of the pole sheet (001) during winding; and performing a curing treatment on the first adhesive layer (131) on the pole tab (111) of the pre-folded pole sheet (001).

24. The method comprises:

24. A method for manufacturing a winding core according to claim 23, further comprising baking the reinforcing layer (013) before pre-folding the pole tabs (111) of the pole sheet (001).

25. The reinforcing layer (013) further comprises an intumescent layer (132), The method comprises:

25. The method for manufacturing a winding core according to claim 23 or 24, further comprising, after applying the first adhesive layer (131) to the end of the polar tab (111) of the polar sheet (001) closer to the body (112), applying the expansion layer (132) to the first adhesive layer (131) on a side remote from the polar tab (111).

26. The reinforcing layer (013) comprises a second adhesive layer (134) and a PI layer (135); The method comprises: After placing the expansion layer (132) on the side of the first adhesive layer (131) away from the polar tab (111), placing said second adhesive layer (134) on a side of said intumescent layer (132) away from said first adhesive layer (131); 26. The method of claim 25, further comprising: placing the PI layer (135) on a side of the second adhesive layer (134) away from the expandable layer (132).

27. The method comprises: Producing and baking said reinforcing layer (013); placing the baked reinforcing layer (013) on the end of the pole tab (111) of the pole sheet (001) close to the body (112); 27. The method for manufacturing a winding core according to any one of claims 22 to 26, further comprising pre-folding the pole tab (111) of the pole sheet (001) during winding, and performing a hardening treatment on the reinforcing layer (013) of the pre-folded pole tab (111).

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