Positive collector plate and cylindrical lithium ion battery

Abstract

The invention provides a positive collector plate and a cylindrical lithium ion battery, the positive collector plate comprises a first plate body located in the center and a second plate body which is connected with the edge of the first plate body and extends outwards in the radial direction, the first plate body is used for being welded with a pole of the cylindrical lithium ion battery, and the second plate body is used for being welded with a roll core of the cylindrical lithium ion battery. A through center hole is formed in the center of the first disc body, the area of the first disc body before the center hole is deducted is S1, the area of the center hole is S2, and the range of S2 / S1 is 4.2%-8.6%. The positive collector plate is matched with a negative collector plate structure capable of performing liquid injection on the negative side, negative side liquid injection or positive side liquid injection can be compatible, any structural change on the positive collector plate is not needed, a manufacturer can manufacture or purchase the positive collector plate as a general structural part, the design and manufacturing cost can be effectively reduced, and the production efficiency is improved. And material management in a factory is also facilitated. In addition, the S2 / S1 range is set to be 4.2%-8.6%, and the welding effect and the liquid injection efficiency of the positive collector plate and the pole can be both considered.

Description

Technical Field

[0001] The present application relates to the technical field of lithium-ion batteries, and in particular to a positive electrode current collecting disc and a cylindrical lithium-ion battery. Background Art

[0002] At present, when assembling 46 series cylindrical lithium-ion batteries, the solution of injecting liquid on the negative electrode side of the battery is usually adopted. In this case, in order to meet the demand of injecting liquid on the negative electrode side, the negative electrode collector plate will be designed with a corresponding structure. Correspondingly, since there is no need for injection on the positive electrode side of the battery, the positive electrode collector plate adopts a simple sheet structure design to reduce design and manufacturing costs. It is understandable that due to the limitations of the positive electrode collector plate structure, it is not possible to easily adjust the injection scheme to achieve injection on the positive electrode side during the manufacturing process. If the manufacturer needs to adjust the injection scheme, it is necessary to change and verify the structure of the positive electrode collector plate separately to meet the demand of injecting liquid on the positive electrode side of the battery. Therefore, the current positive electrode collector plate structure is difficult to meet the demand for injection on the positive electrode side of the battery, and further, it is difficult to meet the demand for flexible production of 46 series cylindrical lithium batteries.

[0003] In addition, the current positive electrode collector is difficult to position when being welded to the winding core due to structural limitations, which increases the difficulty of the welding process and makes it difficult to ensure the welding quality. Summary of the invention

[0004] The embodiments of the present application provide a positive electrode current collecting plate and a cylindrical lithium ion battery, so as to at least solve the technical problem that the existing cylindrical lithium ion battery cannot be conveniently injected at the positive electrode side during injection.

[0005] A first aspect of the present application provides a positive electrode current collector disk for a cylindrical lithium-ion battery, comprising a first disk body located in the center and a second disk body connected to the edge of the first disk body and extending radially outward, the first disk body being used to be welded to the pole of the cylindrical lithium-ion battery, the second disk body being used to be welded to the winding core of the cylindrical lithium-ion battery, a central hole penetrating the first disk body being provided at the center, the area of ​​the first disk body before deducting the central hole being S1, the area of ​​the central hole being S2, and the range of S2 / S1 being 4.2% to 8.6%.

[0006] The positive electrode current collecting disk according to the embodiment of the present application has at least the following beneficial effects:

[0007] By setting a center hole on the first plate body, for cylindrical lithium-ion batteries, with the negative electrode collector plate structure that can be injected on the negative electrode side, it can be compatible with negative electrode side injection or positive electrode side injection. Therefore, in the injection link, you can freely choose to inject liquid on the positive electrode side or the negative electrode side without making any structural changes to the positive electrode collector plate. Manufacturers can manufacture or purchase it as a general structural part, which can effectively reduce design and manufacturing costs and facilitate internal material management in the factory. In addition, by setting the range of S2 / S1 to 4.2% to 8.6%, the welding effect of the positive electrode collector plate and the pole and the injection efficiency can be taken into account.

[0008] In a possible implementation, along the thickness direction of the positive electrode current collecting disk, the first disk body is higher than the second disk body, and the height difference between the surface of the first disk body on one side higher than the second disk body and the surface of the second disk body on the same side is H, and the range of H is 0.6 to 1.4 mm.

[0009] By setting the first disk body to be higher than the second disk body, a chamber can be formed between the bottom of the first disk body and the positive end of the winding core. During liquid injection, the electrolyte flows out of the chamber to the surface of the second disk body and is injected into the interior of the winding core through the through-hole structure on the second disk body, thereby improving the liquid injection efficiency. The range of H is set to 0.6 to 1.4 mm, which can balance the battery performance and liquid injection efficiency.

[0010] In a possible implementation manner, the second disk body includes a connecting portion and a welding portion connected to each other, the welding portion is connected to an edge of the first disk body by the connecting portion, and the connecting portion is provided with a fuse groove at an edge along a length direction thereof.

[0011] By setting a fuse slot, the width of the connection part can be reduced. In the abnormal case of excessive current, when the current passes through this place, the heat increases and reaches the melting point, causing the connection part to fuse at this position, thereby achieving the effect of cutting off the current, thereby reducing the risk of thermal runaway of the battery cell.

[0012] In a possible implementation manner, the connecting portion has a first width W, and the connecting portion has a second width W1 in a region where the fuse groove is provided, and W1 / W is in a range of 42% to 63%.

[0013] By setting the range of W1 / W to 42% to 63%, the fusing effect of the connection portion 121 can be ensured, thereby ensuring the safety performance of the battery.

[0014] In a possible implementation manner, the connecting portion has a first edge extending along a length direction for forming the fuse slot, and the length of the first edge is L1, and the range of L1 is 2-4 mm.

[0015] By setting the range of L1 to 2 to 4 mm, the yield rate can be improved and the cost can be reduced while ensuring battery safety.

[0016] In a possible implementation, the connecting portion includes:

[0017] A plurality of first connection portions arranged at intervals along the circumference of the first disk body and extending radially outward from the edge thereof, wherein the fuse slot is provided at the first connection portion;

[0018] A second connection portion formed by extending the outer end portions of each of the first connection portions toward both sides along the circumferential direction;

[0019] There are a plurality of welding parts, each of which is arranged one by one in a region defined by two adjacent first connecting parts and the second connecting parts, and is formed by extending radially inwardly from the inner edge of the second connecting part.

[0020] By dividing the positive electrode current collector into a plurality of clearly defined welding areas, it is easy to position the area through tooling and to weld the area through welding equipment during welding. Moreover, after welding, it is convenient to judge whether the welding position is reasonable through visual observation, thereby reducing the difficulty of identification and the workload.

[0021] In a possible embodiment, the edges on both sides of the welding portion and the inner edge of the second connecting portion define a slit extending in the circumferential direction, the circumference of the outer edge of the second connecting portion is L, the total arc length of the slit is L2, and the range of L2 / L is 43% to 58%.

[0022] By setting the range of L2 / L to 43% to 58%, the injection efficiency can be improved while ensuring the welding effect of the positive electrode current collecting disk 100, and the yield rate can also be increased to reduce the cost.

[0023] In a possible implementation manner, the second connection portion is provided with a plurality of evenly distributed notches at an edge outside a position corresponding to the welding portion, the total arc length of the notches is L3, and the range of L3 / L is 4% to 9%.

[0024] By setting the range of L3 / L to 4% to 9%, both the welding effect and the injection efficiency of the positive electrode current collecting disk 100 can be achieved.

[0025] In a possible implementation manner, the maximum depth of the notch is L5, and the range of L5 is 0.9-2.1 mm.

[0026] By setting the range of L5 to 0.9 to 2.1 mm, both the welding effect and the injection efficiency of the positive electrode current collecting disk 100 can be achieved.

[0027] In a possible implementation manner, the width of the slit along the radial direction is L4, and the range of L4 is 0.4-1.5 mm.

[0028] By setting the range of L4 to 0.4 to 1.5 mm, both the welding effect and the liquid injection efficiency between the positive electrode current collecting disk 100 and the winding core 300 can be achieved.

[0029] In a possible implementation manner, the second connection portion has a width W2 in the radial direction in a region corresponding to the slit, and W2 is in the range of 1 to 3 mm.

[0030] By setting the range of W2 to 1 to 3 mm, it is possible to achieve both the welding effect between the positive electrode current collecting disk 100 and the winding core 300 and the safety of the battery.

[0031] The second aspect of the present application provides a cylindrical lithium-ion battery, comprising the positive current collector disk described in the first aspect, and also comprising a pole, a winding core and a shell, wherein the pole is installed in the shell, the winding core is located in the shell, the first disk body in the positive current collector disk is welded to the pole, and the second disk body is welded to the positive end of the winding core.

[0032] The cylindrical lithium-ion battery according to the embodiment of the present application has at least the following beneficial effects:

[0033] Since a center hole is provided on the first plate body of the positive electrode current collecting plate, combined with the negative electrode current collecting plate structure capable of liquid injection on the negative electrode side, it is compatible with negative electrode side liquid injection or positive electrode side liquid injection, and by setting the range of S2 / S1 at 4.2% to 8.6%, it is possible to take into account both the welding effect of the positive electrode current collecting plate and the pole and the liquid injection efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the description of the embodiments of the present application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0035] Figure 1 It is a structural schematic diagram of a positive electrode current collector provided in an embodiment of the present application;

[0036] Figure 2 yes Figure 1 A schematic diagram of the structure of a cylindrical lithium-ion battery assembled with a positive electrode current collecting plate;

[0037] Figure 3 yes Figure 1 Schematic diagram of area S1 in the positive electrode current collecting disk;

[0038] Figure 4 yes Figure 1 Schematic diagram of area S2 in the positive electrode current collecting disk;

[0039] Figure 5 yes Figure 3 Schematic cross-sectional view along the AA direction;

[0040] Figure 6 yes Figure 5 The local schematic diagram of point B in the middle;

[0041] Figure 7 yes Figure 1 A schematic top view of the positive electrode current collecting disk in FIG.

[0042] Figure 8 yes Figure 7 The local schematic diagram of the C in the middle;

[0043] Fig. 9 yes Figure 7 Partial schematic diagram at point D in the middle.

[0044] Reference numerals:

[0045] 100-positive electrode current collecting disc, 110-first disc body, 111-center hole, 120-second disc body, 121-connecting portion, 1211-first connecting portion, 1212-second connecting portion, 122-welding portion, 130-fuse groove, 131-first edge, 132-second edge, 133-third edge, 140-slit, 150-notch, 160-pit, 170-liquid outlet;

[0046] 200-pole, 210-liquid injection hole;

[0047] 300-winding core, 310-positive terminal, 320-winding core hole;

[0048] 400-housing. DETAILED DESCRIPTION

[0049] Embodiments of the present embodiment are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present embodiment, and should not be construed as limiting the present embodiment.

[0050] In the description of this embodiment, it should be understood that descriptions involving orientation, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing this embodiment and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on this embodiment.

[0051] In the description of this embodiment, "several" means one or more, "more" means more than two, "greater than", "less than", "exceed", etc. are understood to exclude the number itself, and "above", "below", "within", etc. are understood to include the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0052] In the description of this embodiment, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in this embodiment based on the specific content of the technical solution.

[0053] Figure 1 is a schematic structural diagram of a positive electrode current collecting disk 100 provided in an embodiment of the present application, Figure 2 yes Figure 1 The positive electrode current collecting plate 100 is assembled into a schematic diagram of the structure of a cylindrical lithium-ion battery, as shown in Figure 1 and Figure 2 As shown, the positive electrode current collecting disc 100 includes a first disc body 110 and a second disc body 120, wherein the first disc body 110 is used to connect with the pole 200, and the second disc body 120 is used to connect with the winding core 300, so as to form a passage between the winding core 300 and the pole 200. It can be understood that, as Figure 2 As shown, in the cylindrical lithium-ion battery, the pole 200 and the winding core 300 are respectively located in the thickness direction of the positive electrode current collecting disk 100 ( Figure 2 Therefore, the upper surface of the first disk body 110 is connected to the bottom of the pole 200, and the lower surface of the second disk body 120 is connected to the positive terminal 310 of the winding core 300.

[0054] It can be understood that the winding core 300 of the cylindrical lithium-ion battery is made by a winding process. After winding, the winding core 300 is cylindrical, and a circular winding core hole 320 is formed at the center, and the inner cavity of the shell 400 of the cylindrical lithium-ion battery is also a circular cross-section. In order to adapt to the circular cross-sectional shape of the winding core 300 and the shell 400, and to improve space utilization, the positive electrode collector disk 100 is in a circular thin disk shape, and can usually be made of materials such as aluminum. In addition, in order to correspond to the position of the pole 200 in the cylindrical lithium-ion battery, the first disk body 110 is located in the central area of ​​the positive electrode collector disk 100, and the second disk body 120 is located in the peripheral area of ​​the positive electrode collector disk 100, that is, when viewed in the radial direction, the second disk body 120 is formed by radially extending from the edge of the first disk body 110. As a result, the lower surface of the second disk body 120 can just correspond to the positive terminal 310 outside the winding core hole 320.

[0055] Furthermore, the pole 200 of the cylindrical lithium-ion battery is generally a columnar structure with a circular bottom surface. In order to match the circular bottom surface shape of the pole 200, in some embodiments, such as Figure 1 As shown, the first disk body 110 can be circular, and in order to match the circular end face shape of the positive terminal 310, the second disk body 120 can be circular, thereby, the required welding area can be formed between the first disk body 110 and the pole 200, and between the second disk body 120 and the positive terminal 310, so as to form a good welding connection between the two.

[0056] Continue to refer Figure 1 In the embodiment of the present application, a center hole 111 is provided at the center of the first plate body 110, and the center hole 111 is used for injecting liquid on the positive electrode side. Figure 2 On the positive electrode side of the cylindrical lithium-ion battery, by providing an injection hole 210 on the pole 200, the injection hole 210 can be aligned with and connected to the center hole 111, so that the electrolyte can be injected from the outside through the channel formed by the injection hole 210 and the center hole 111, so as to achieve injection on the positive electrode side. Further, in order to match the shape of the circular winding core hole 320, the center hole 111 is preferably a circular hole.

[0057] It can be understood that the positive electrode current collecting plate 100 provided in the embodiment of the present application is compatible with negative electrode side injection or positive electrode side injection by setting a center hole 111 on the first plate body 110 for cylindrical lithium-ion batteries, in combination with a negative electrode current collecting plate structure capable of injecting liquid on the negative electrode side. Therefore, in the injection process, it is possible to freely choose to inject liquid on the positive electrode side or the negative electrode side without making any structural changes to the positive electrode current collecting plate 100. Manufacturers can manufacture or purchase it as a general structural part, which can effectively reduce design and manufacturing costs and facilitate internal material management in the factory.

[0058] refer to Figure 3 and Figure 4 In the embodiment of the present application, the area of ​​the first plate body is S1, the area of ​​the center hole 111 is S2, and the range of S2 / S1 is 4.2% to 8.6%. For example, S2 / S1 can be 4.2%, 5%, 6.8%, 8.6%, etc. In some embodiments, the area S1 of the first plate body 110 is 107.51mm 2 , the area S2 of the center hole 111 is 7.51 mm 2 . If S2 / S1 is greater than 8.6%, the effective welding area of ​​the welding area of ​​the first disk body 110 will be reduced, thereby reducing the flow capacity of the weld, and will cause the flow temperature rise in the weld area to increase, which will increase the internal resistance of the battery and reduce the overall performance of the battery. On the contrary, if S2 / S1 is less than 4.2%, during the injection, the electrolyte inflow time is too long, which reduces the injection efficiency, and further reduces the production efficiency and increases the manufacturing cost of the battery. By setting the range of S2 / S1 to 4.2% to 8.6%, the welding effect and injection efficiency of the positive electrode current collector 100 and the pole 200 can be taken into account.

[0059] In some embodiments, the diameter of the center hole 111 is D, and the range of D is 2 to 4 mm. For example, the diameter of the center hole 111 is D, which is 2 mm, 3 mm or 4 mm. If D is greater than 4 mm, the effective welding area of ​​the welding area of ​​the first disk body 110 will be reduced, thereby reducing the flow capacity of the weld, and will cause the flow temperature rise in the weld area to increase, thereby increasing the internal resistance of the battery and reducing the overall performance of the battery. On the contrary, if D is less than 2 mm, during the injection, the electrolyte inflow time is too long, thereby reducing the injection efficiency, thereby reducing the production efficiency and increasing the manufacturing cost of the battery. By setting the range of D to 2 to 4 mm, the welding effect and injection efficiency of the positive electrode current collector 100 and the pole 200 can be taken into account.

[0060] In some embodiments, Figure 3 and Figure 4 As shown, combined with Figure 2 , along the thickness direction of the positive electrode current collecting disk 100 ( Figure 2In the height direction of the first plate 110, the first plate 110 and the second plate 120 are staggered, that is, the first plate 110 is higher than the second plate 120. It can be understood that at this time, a pit 160 is formed in the area corresponding to the first plate 110 at the bottom of the positive current collector 100. Therefore, after the positive current collector 100 is assembled to the cylindrical lithium-ion battery, the bottom of the first plate 110 can define a chamber with the positive terminal 310 of the winding core 300. When the liquid is injected, the chamber can temporarily store the electrolyte injected through the center hole 111. In addition, since the surface of the first plate 110 used for welding with the pole 200 is not coplanar with the upper surface of the second plate 120, its surface area is small. Therefore, the surface flatness of the first plate 110 can be better guaranteed, so that it can fit well with the bottom surface of the pole 200, thereby improving the welding effect.

[0061] Furthermore, a liquid outlet 170 is provided on the positive electrode current collecting disk 100 to connect the recess 160 with the upper surface of the second disk body 120. It is understandable that during liquid injection, the electrolyte entering the chamber can spread to the upper surface of the second disk body 120 through the liquid outlet 170, and be injected into the interior of the winding core 300 through the through-hole structure constructed on the second disk body 120, such as the slit 140 and the notch 150 to be described below, thereby effectively improving the liquid injection efficiency.

[0062] Furthermore, in some embodiments, the height difference between the side surface of the second plate 120 close to the first plate 110 and the surface of the first plate 110 is H, and the range of H is 0.6-1.4 mm. For example, H can be 0.6 mm, 0.8 mm, 1.1 mm or 1.4 mm. It should be noted that the surface of the first plate 110 described here refers to the surface used for welding with the pole 200, that is, Figure 3 and Figure 4 The upper surface of the second plate 120, and the side surface of the second plate 120 close to the first plate 110 refers to the surface located on the same side as the surface for welding with the pole 200, that is, Figure 3 and Figure 4. If H is greater than 1.4 mm, the positive electrode collector disk 100 will occupy the assembly space of the battery internal winding core 300, resulting in a decrease in the capacity and performance of the battery. On the contrary, if H is less than 0.6 mm, the height of the first disk body 110 relative to the second disk body 120 is too low, resulting in the chamber space formed between the bottom of the first disk body 110 and the positive terminal 310 of the winding core 300 being too small. During injection, the electrolyte flows out of the chamber to the surface of the second disk body 120, and the time for the electrolyte to flow into the interior of the winding core 300 through the through-hole structure on the second disk body 120 is too long, thereby reducing the injection efficiency, which in turn leads to reduced production efficiency and increased battery manufacturing costs. In addition, there is a high risk of electrolyte overflowing from the injection hole during injection. By setting the range of H to 0.6 to 1.4 mm, it is possible to balance battery performance and injection efficiency.

[0063] In some embodiments, Figure 1 , Figure 3 , Figure 4 as well as Figure 7 As shown, the second disk body 120 includes a connecting portion 121 and a welding portion 122 connected to each other, and the welding portion 122 is connected to the edge of the first disk body 110 by the connecting portion 121. It can be understood that, among the connecting portion 121 and the welding portion 122 constituting the second disk body 120, the welding portion 122 is used to be welded to the positive terminal 310 of the winding core 300, and the connecting portion 121 is used to connect the welding portion 122 to the first disk body 110. In this embodiment, a fuse slot 130 is provided at the edge of the connecting portion 121 along its length direction. Specifically, the fuse slot 130 is a structure formed by concavely forming the edge of the connecting portion 121 in the length direction along the width direction. The fuse slot 130 can reduce the width of the connecting portion 121. In the abnormal case of excessive current, when the current passes through this place, the heat rises and reaches the melting point, so that the connecting portion 121 is melted at this position, achieving the effect of cutting off the current, thereby reducing the risk of thermal runaway of the battery cell. It is understandable that when the second disk body 120 is provided with multiple groups of connection parts 121 and welding parts 122, each connection part 121 is provided with a fuse slot 130 so as to completely cut off the current flowing through the positive current collecting disk 100 in the abnormal situation of excessive current.

[0064] Specifically, the connection portion 121 is in the shape of an elongated strip and extends in the radial direction, with a certain width extending in the circumferential direction. A total of two fuse slots 130 are provided on each connection portion, and the two fuse slots 130 are symmetrically arranged on both sides of the width direction of the connection portion 121. In addition, since the positive electrode current collecting disk 100 itself is in the shape of a thin sheet, the connection portion 121 is also in the shape of a thin sheet in terms of thickness. Therefore, by arranging the fuse slots 130 on both sides in the width direction thereof, the cross-sectional area of ​​the section at this position can be significantly reduced, so that the connection portion 121 can be quickly blown in the abnormal situation of excessive current.

[0065] Further, refer to Figure 8 In some embodiments, the connection portion 121 has a first width W, and the connection portion 121 has a second width W1 in the area where the fuse slot 130 is provided, and the range of W1 / W is 42% to 63%. For example, W1 / W can be 42%, 48%, 56%, 63%, etc. In some embodiments, the first width W is 4 mm, and the second width W1 is 2 mm. The second width W1 in the embodiment of the present application means that due to the design of the fuse slot 130, the width of the connection portion 121 changes relative to the first width W. Based on the definition of the second width W1 in the embodiment of the present application, the first width W in the present application also refers to the width of the connection portion 121 at a position other than the fuse slot 130 on the connection portion 121. Furthermore, the first width W and the second width W1 are of equal width.

[0066] If W1 / W is greater than 63%, the second width W1 of the connection portion 121 at the corresponding fuse slot 130 is too wide, and it cannot be quickly fused under abnormal conditions of excessive current, increasing safety risks. On the contrary, if W1 / W is less than 42%, the second width W1 of the connection portion 121 at the corresponding fuse slot 130 is too small, which will make the fusing sensitivity too high, easily causing the battery to fail due to short circuit, and on the other hand, increase the internal resistance, affecting the normal use of the battery. By setting the range of W1 / W to 42% to 63%, the fusing effect of the connection portion 121 can be guaranteed, thereby ensuring the safety performance of the battery.

[0067] In some embodiments, the connection portion 121 has a first edge 131 extending along the length direction for forming the fuse slot 130, and the length of the first edge 131 is L1, and the range of L1 is 2 to 4 mm. For example, L1 is 2 mm, 3 mm or 4 mm. As mentioned above, the positive electrode collector 100 is usually made of aluminum, which is soft and has low strength. Therefore, if L1 is greater than 4 mm, the connection portion 121 is more likely to deform or even break at the location of the fuse slot 130, and the positive electrode collector 100 itself is easily scrapped, causing waste and increasing the difficulty of management. In addition, if the metal chips generated thereby fall into the battery, there will be a risk of battery short circuit, and the burrs and sharp corners at the cross section will also have the risk of piercing the diaphragm and causing the battery short circuit, thereby increasing the safety risk of the battery. On the contrary, if L1 is less than 2 mm, heat is easily transferred to the first plate 110 and the welding part 122, which will reduce the fusing sensitivity of the fusing slot 130 and prolong the fusing time, thereby increasing the safety risk of the battery. By setting the range of L1 to 2 to 4 mm, the yield rate can be improved while ensuring the safety of the battery, thereby reducing the cost.

[0068] It can be understood that, in this embodiment, both sides of the connecting portion 121 in the width direction are provided with the fuse slots 130, so the aforementioned second width W1 is the vertical distance between the first edges 131 of the two fuse slots 130. Figure 8 As shown, in addition to the first edge 131, the bottom of the fuse slot 130 also has a second edge 132 and a third edge 133 respectively connected to the two ends of the first edge 131, and the first edge 131, the second edge 132 and the third edge 133 together constitute the fuse slot 130 which is generally trapezoidal in shape.

[0069] Continue to refer Figure 1 , Figure 3 , Figure 4 as well as Figure 7In some embodiments, the second disk body 120 includes a connecting portion 121 and a welding portion 122. Further, the connecting portion 121 includes a first connecting portion 1211 and a second connecting portion 1212. There are multiple first connecting portions 1211, which are arranged at intervals along the circumference of the first disk body 110 and extend radially outward from its edge. In other words, these first connecting portions 1211 are distributed in a radial shape with the center of the first disk body 110 as the center. The second connecting portion 1212 is formed by the outer end of each first connecting portion 1211 extending to both sides along the circumference. In addition, there are multiple welding portions 122, each of which is correspondingly arranged in the area jointly defined by two adjacent first connecting portions 1211 and the second connecting portion 1212, and is formed by the inner edge of the second connecting portion 1212 extending radially inward. It can be understood that the second connection portion 1212 formed by the outer end of each first connection portion 1211 extending circumferentially constitutes an annular structure surrounding the periphery of the first disk body 110 , and the outer edge of this annular structure is used to define the boundary of the entire positive electrode current collecting disk 100 .

[0070] It is understandable that, in order to simplify the structure, the aforementioned fuse slot 130 can be disposed on the first connecting portion 1211 .

[0071] It can be understood that in the above structure, a plurality of welding portions 122 for welding with the positive terminal 310 are provided, and the number thereof corresponds to the number of the first connection portions 1211. For example, the number of the first connection portions 1211 is 3, and the number of the welding portions 122 is also 3 accordingly, and these welding portions 122 are arranged in a plurality of areas separated by the first connection portions 1211 along the circumferential direction, so that when observing from the top view of the positive electrode current collecting disk 100, it is divided into a plurality of welding areas, and the boundaries of these welding areas are clear. Therefore, during welding, it is easy to position by tooling and to weld by welding equipment, and after welding, it is convenient to judge whether the welding position is reasonable by visual observation or visual inspection equipment, which can reduce the difficulty of identification and workload.

[0072] It can be further understood that the welding portion 122 is formed by extending inward from the inner edge of the second connecting portion 1212. In some embodiments, in order to increase the welding area of ​​each welding portion 122 (refer to Figure 7The shaded portion E in the figure, the edge of the welding portion 122 extends close to the edge of the first disk body 110 and the edge of the first connecting portion 1211, thereby, there is a gap extending in the circumferential direction between the welding portion 122 and the first disk body 110, and the gap can be used as the aforementioned liquid outlet 170, so that when injecting liquid, the electrolyte entering the chamber can spread to the upper surface of the second disk body 120 through the liquid outlet 170. Further, there is a gap extending in the radial direction between the welding portion 122 and the first connecting portions 1211 located on both sides thereof, and the gap can be used as a through-hole structure for injecting liquid into the winding core 300. It can be understood that in the above structure, the gap formed between the welding portion 122 and the first disk body 110 and the first connecting portion 1211 is connected, so the electrolyte can flow along the two gaps, which can improve the injection efficiency.

[0073] Furthermore, in some embodiments, Figure 7 As shown, the edges on both sides of the welding portion 122 and the inner edges of the second connecting portion 1212 define a slit 140 extending in the circumferential direction. By defining the slit 140 extending in the circumferential direction on the edges on both sides of the welding portion 122 and the inner edges of the second connecting portion 1212, during liquid injection, at the far end away from the first disk body 110, the electrolyte can be injected into the interior of the winding core 300 through the slit 140, thereby improving the injection efficiency.

[0074] In some embodiments, the circumference of the outer edge of the second connecting portion 1212 is L, the total arc length of the slit 140 is L2, and the range of L2 / L is 43% to 58%. For example, L2 / L can be 43%, 50%, 58%, etc. For example, in some embodiments, L is 133.52 mm, the number of welding portions 122 is 3, the number of slits 140 is 6, and the total arc length L2 of the 6 slits 140 is 66.78 mm. It should be noted that the circumference L referred to in the embodiments of the present application refers to the circumference of the entire circle where the outer edge of the circular ring structure formed by the second connecting portion 1212 extending circumferentially from the outer end of each first connecting portion 1211 is located, that is, Figure 7 The circumference of the circle where the reference line F at the middle notch 150 is located is for ease of understanding. Figure 7 The outer edge of the second connection portion 1212 is indicated by a dotted line. Fig. 9Only a part of L2 is marked, that is, the arc length of a section of the slit 140, and L2 here also includes the arc length of the gap formed by the welding part 122 and the first connecting part 1211 connected to the slit 140. If L2 / L is greater than 58%, the structural strength of the connecting part between the welding part 122 and the second connecting part 1212 is low, and it is easy to deform, which is difficult to ensure the welding effect, and the low yield rate will also lead to increased costs. On the contrary, if L2 / L is less than 43%, when injecting liquid, the time required for the electrolyte to be injected into the inside of the winding core through the slit 140 is still relatively long, and the slit 140 does not significantly improve the injection efficiency. By setting the range of L2 / L to 43% to 58%, the injection efficiency can be improved while ensuring the welding effect of the positive electrode collector 100, and the yield rate can also be improved to reduce costs.

[0075] Further, in some embodiments, the width of the slit 140 in the radial direction is L4, and the range of L4 is 0.4 to 1.5 mm. For example, L4 is 0.4 mm, 0.8 mm, 1.2 mm or 1.5 mm, etc. If L4 is greater than 1.6 mm, the opening area of ​​the slit 140 will occupy the welding area between the welding portion 122 and the winding core 300, resulting in a reduction in the effective welding area, causing the flow capacity of the weld to decrease, and then causing the temperature rise of the weld to increase. On the contrary, if L4 is less than 0.4 mm, during liquid injection, the speed at which the electrolyte flows into the interior of the winding core 300 through the slit 140 is slow, and the slit 140 does not significantly improve the injection efficiency. By setting the range of L4 to 0.4 to 1.5 mm, the welding effect and injection efficiency of the positive electrode current collecting disk 100 and the winding core 300 can be taken into account.

[0076] Further, in some embodiments, the second connection portion 1212 has a width W2 in the radial direction in the area corresponding to the slit 140, and the range of W2 is 1 to 3 mm. For example, W2 can be 1 mm, 3 mm, etc. If W2 is greater than 3 mm, the second connection portion will excessively invade the central area of ​​the positive current collector 100, so that the effective welding area between the welding portion 122 and the winding core 300 is reduced, resulting in a decrease in the current capacity of the welding point, and then the temperature rise of the welding point will increase. On the contrary, if W2 is less than 1 mm, the structural strength of the second connection portion 1212 at this position is insufficient, and it is easy to break. If the metal chips generated thereby fall into the battery, there will be a risk of battery short circuit, and the burrs and sharp corners at the cross section will also have the risk of piercing the diaphragm and causing the battery short circuit, thereby increasing the safety risk of the battery. By setting the range of W2 to 1 to 3 mm, the welding effect of the positive current collector 100 and the winding core 300 and the safety of the battery can be taken into account.

[0077] In some embodiments, Figure 7As shown, the second connection portion 1212 is provided with a plurality of evenly distributed notches 150 on the outer edge. Specifically, for example, the notches 150 can be formed by the outer edge of the second connection portion 1212 being concave inwardly along the radial direction. Thus, the notches 150 are defined by the concave edge of the second connection portion 1212 and its reference line, wherein the reference line F can refer to Fig. 9 The dotted line at the notch 150 in the figure is used for illustration only. The dotted line represents the shape when the notch 113 is not formed on the outer edge of the second connecting portion 1212, that is, the dotted line is obtained by extending the outer edge of the second connecting portion 1212 according to its natural direction. By providing the notch 150, during liquid injection, the electrolyte that spreads along the upper surface of the second disk body 120 to its edge can flow into the inside of the winding core 300 along the notch 150, thereby further improving the liquid injection efficiency.

[0078] Further, in some embodiments, the position of the notch 150 in the circumferential direction of the second connecting portion 1212 corresponds to the welding portion 122, that is, along the radial direction, the center of the notch 150 is collinear with the center of the welding portion 122, and the total arc length of the notch 150 is L3, and the range of L3 / L is 4% to 9%. For example, L3 / L can be 4%, 6%, 9%, etc. For example, in some embodiments, the number of notches 150 is 3, and the total arc length L3 of the 3 notches 150 is 9 mm. It should be noted that the arc length of the notch 150 referred to in the embodiments of the present application refers to the arc length of the reference line F that defines the formation of the notch 150, therefore, Fig. 9 Only a portion of L3 is marked. If L3 / L is greater than 9%, the connection area between the second connection portion 1212 and the welding portion 122 is too small, which makes it difficult to ensure the flatness of the welding portion 122, and thus the welding effect is difficult to ensure. On the contrary, if L3 / L is less than 4%, during injection, the electrolyte flows into the interior of the winding core 300 through the notch 150 at a relatively slow speed, and the notch 150 does not significantly improve the injection efficiency. By setting the range of L3 / L to 4% to 9%, both the welding effect and the injection efficiency of the positive electrode current collector 100 can be taken into account.

[0079] Furthermore, in some embodiments, Fig. 9As shown, the maximum depth of the notch 150 is L5, and the range of L5 is 0.9 to 2.1 mm. For example, L5 is 0.9 mm, 1.5 mm or 2.1 mm. If L5 is greater than 2.1 mm, the notch 150 will occupy the welding area between the welding portion 122 and the core 300, resulting in a reduction in the effective welding area, causing the current capacity of the weld to decrease, and then causing the temperature rise of the weld to increase. On the contrary, if L5 is less than 0.9 mm, during liquid injection, the electrolyte flows into the core 300 through the notch 150 at a slow speed, and the notch 150 does not significantly improve the injection efficiency. By setting the range of L5 to 0.9 to 2.1 mm, the welding effect and injection efficiency of the positive electrode current collector 100 can be taken into account.

[0080] The effects of the present application are further described below with specific examples and comparative examples.

[0081] Embodiment 1:

[0082] Embodiment 1 provides a cylindrical lithium-ion battery, which includes a positive electrode current collector disk 100, the positive electrode current collector disk 100 includes a first disk body 110 and a second disk body 120 staggered in the thickness direction, the surface of the first disk body 110 higher than the second disk body 120 has a height difference H from the surface of the second disk body 110 on the same side, the first disk body 110 is provided with a circular center hole 111 at the center, the second disk body 120 includes three first connecting parts 1211 extending radially outward from the edge of the first disk body 110, and the two sides of the outer ends of the three first connecting parts 1211 extend circumferentially to form The second connection parts 1212, these second connection parts 1212 together form an annular structure, and, in each area formed by the three first connection parts 1211 in pairs in the circumferential direction, the inner edges of the second connection parts 1212 extend inwardly to form a welding part 122, and a slit 140 extending along the circumferential direction is defined between the edges on both sides of the welding part 122 and the inner edges of the second connection parts 1212, and a pair of trapezoidal fuse grooves 130 are provided on the edges in the length direction of each first connection part 1211, and a notch 150 is provided on the outer edge of the second connection part 1212 corresponding to the position of the welding part 122.

[0083] In addition, the positive electrode current collecting disk 100 also meets the following parameters:

[0084] The area S1 of the first plate 110 is 107.51 mm 2 , the area S2 of the center hole 111 is 7.07 mm 2, H=1mm, the first width W=4mm of the first connecting portion 1211, the second width W1=2mm of the first connecting portion 1211 at the position where the fuse slot 130 is set, the length L1=3mm of the first edge 131 at the bottom of the fuse slot 130, the circumference L=133.52mm of the outer edge of the second connecting portion 1212, the total arc length L2=66.78mm of the 6 slits 140, the width L4=0.8mm of the slit 140, the width W2=2mm of the second connecting portion 1212 in the area corresponding to the slit 140, the total arc length L3=9mm of the 3 notches 150, and the maximum depth L5=1.5mm of the notch 150.

[0085] From the above, it can be seen that in the positive electrode current collecting disk 100, S2 / S1=6.6%, W1 / W=50%, L2 / L=50%, and L3 / L=6.74%.

[0086] Comparative Example 1:

[0087] Comparative Example 1 provides a cylindrical lithium-ion battery, which includes a positive electrode current collecting disk 100 , and the difference between Comparative Example 1 and Example 1 is that S2 / S1 = 3%.

[0088] Comparative Example 2:

[0089] Comparative Example 2 provides a cylindrical lithium-ion battery, which includes a positive electrode current collecting disk 100 , and the difference between Comparative Example 2 and Example 1 is that S2 / S1 = 10%.

[0090] Comparative Example 3:

[0091] Comparative Example 3 provides a cylindrical lithium-ion battery, which includes a positive electrode current collecting disk 100 , which is different from Example 1 in that: H=0.3 mm.

[0092] Comparative Example 4:

[0093] Comparative Example 4 provides a cylindrical lithium-ion battery, which includes a positive electrode current collecting disk 100 , which is different from Example 1 in that: H=1.7 mm.

[0094] Comparative Example 5:

[0095] Comparative Example 5 provides a cylindrical lithium-ion battery, which includes a positive electrode current collecting disk 100, which is different from Example 1 in that: W1 / W=36%.

[0096] Comparative Example 6:

[0097] Comparative Example 6 provides a cylindrical lithium-ion battery, which includes a positive electrode current collecting disk 100, which is different from Example 1 in that: W1 / W=68%.

[0098] Comparative Example 7:

[0099] Comparative Example 7 provides a cylindrical lithium-ion battery, which includes a positive electrode current collecting disk 100, which is different from Example 1 in that: L1 = 1.5 mm.

[0100] Comparative Example 8:

[0101] Comparative Example 8 provides a cylindrical lithium-ion battery, which includes a positive electrode current collecting disk 100, which is different from Example 1 in that: L1 = 4.5 mm.

[0102] Comparative Example 9:

[0103] Comparative Example 9 provides a cylindrical lithium-ion battery, which includes a positive electrode current collecting disk 100, and the difference between the comparative example 9 and the embodiment 1 is that L2 / L=36%.

[0104] Comparative Example 10:

[0105] Comparative Example 10 provides a cylindrical lithium-ion battery, which includes a positive electrode current collecting disk 100, and the difference between the comparative example 1 and the embodiment 1 is that L2 / L=68%.

[0106] Comparative Example 11:

[0107] Comparative Example 11 provides a cylindrical lithium-ion battery, which includes a positive electrode current collecting disk 100, and the difference between the comparative example 1 and the embodiment 1 is that L3 / L=2%.

[0108] Comparative Example 12:

[0109] Comparative Example 12 provides a cylindrical lithium-ion battery, which includes a positive electrode current collecting disk 100, and the difference between the comparative example 1 and the embodiment 1 is that L3 / L=14%.

[0110] Comparative Example 13:

[0111] Comparative Example 13 provides a cylindrical lithium-ion battery, which includes a positive electrode current collecting disk 100, which is different from Example 1 in that: L4 = 0.3 mm.

[0112] Comparative Example 14:

[0113] Comparative Example 14 provides a cylindrical lithium-ion battery, which includes a positive electrode current collecting disk 100, which is different from Example 1 in that: L4 = 1.8 mm.

[0114] Comparative Example 15:

[0115] Comparative Example 15 provides a cylindrical lithium-ion battery, which includes a positive electrode current collecting disk 100, which is different from Example 1 in that: W2 = 0.7 mm.

[0116] Comparative Example 16:

[0117] Comparative Example 16 provides a cylindrical lithium-ion battery, which includes a positive electrode current collecting disk 100, which is different from Example 1 in that: W2 = 3.5 mm.

[0118] Comparative Example 17:

[0119] Comparative Example 17 provides a cylindrical lithium-ion battery, which includes a positive electrode current collecting disk 100, which is different from Example 1 in that: L5 = 0.6 mm.

[0120] Comparative Example 18:

[0121] Comparative Example 18 provides a cylindrical lithium-ion battery, which includes a positive electrode current collecting disk 100, which is different from Example 1 in that: L5 = 2.6 mm.

[0122] Comparative Example 19:

[0123] Comparative Example 19 provides a cylindrical lithium-ion battery, which includes a positive electrode current collecting disk 100, which differs from Example 1 in that the fuse slot 130 is not provided.

[0124] Comparative Example 20:

[0125] Comparative Example 20 provides a cylindrical lithium-ion battery, which includes a positive electrode current collecting disk 100 , which differs from Example 1 in that no notch 150 is provided.

[0126] Table 1 below shows the time (t) required for electrolyte injection into the battery, the maximum welding temperature (T1max) of the first plate body 110, the maximum welding temperature (T2max) of the second plate body 120, the maximum temperature (T3max) at the fuse slot 130, the number of times the first connection portion 1211 is folded in half at the fuse slot 130 to break (C1), the number of times the second connection portion 1212 is folded in half to break (C2), and the battery short circuit rate test for the positive electrode current collecting plate 100 manufactured in the above-mentioned embodiment and comparative example, wherein:

[0127] The test method for the time (t) required for the electrolyte to be injected into the battery is as follows: assemble the positive electrode current collecting plate 100 into a cylindrical lithium-ion battery. In the injection stage, inject 77g of electrolyte into the liquid holding cup, align the suction nozzle of the liquid holding cup with the injection hole 210 on the pole 200 and press it tightly. First, draw negative pressure in the liquid holding cup for 15s, and draw it to -90KPa. It can be observed from the liquid holding cup that the electrolyte height drops, and the electrolyte flows into the battery. After maintaining for 40s, positive pressure injection is performed, and nitrogen is flushed into the battery. The battery gradually becomes a positive pressure of 0.8MPa. The electrolyte in the liquid holding cup continues to flow into the battery, and the height of the electrolyte in the liquid holding cup gradually decreases, and then adjust to negative pressure injection, maintain, and then adjust to positive pressure injection, maintain, and the positive and negative pressure injection cycles are repeated many times until the electrolyte in the liquid holding cup completely flows into the battery, and the electrolyte height in the liquid holding cup is 0. The time t (unit: second) when the electrolyte completely flows into the battery is recorded at this time.

[0128] The test method for the maximum welding temperature (T1max) of the first disk body 110, the maximum welding temperature (T2max) of the second disk body 120, and the maximum temperature (T3max) at the fuse slot 130 is as follows: in the process of assembling the cylindrical lithium-ion battery, the temperature collection line is inserted into the battery through the injection hole 210 of the pole 200, one is attached to the welding point between the first disk body 110 and the pole 200, one is attached to the welding point between the second disk body 120 and the positive terminal 310 of the winding core 300, and the other is attached to the position where the fuse slot 130 is set on the first connecting part 1211, and then the normal process flow is followed to manufacture and finally obtain the finished battery, and then 10 cycles of charge and discharge are performed at a rate of 2C, and the maximum temperatures T1max, T2max and T3max (unit: Celsius) at the three positions obtained by the temperature collection line are recorded.

[0129] The test method for the number of folding times (C1) at which the first connection portion 1211 breaks after being folded at the fuse slot 130 is as follows: use scissors to cut along the radial direction from two adjacent notches 150 to obtain a 1 / 3 piece of the positive electrode current collecting disk 100 containing a first connection portion 1211, and fold this part of the disk along the center line of the fuse slot 130. After the two surfaces are completely fitted together, unfold them to 180° and count them as one fold. Continue until a break occurs at the crease, then stop folding and record the number of folding times.

[0130] The test method for the number of folding times (C2) at which the second connection portion 1212 breaks after being folded is as follows: use scissors to cut along the radial direction from a notch 150, and after cutting to the center hole 111, cut radially along the edge of a first connection portion 1211 until the second connection portion 1212 is broken, and fold the obtained fan-shaped partial positive electrode current collecting disk 100 into two fan-shaped parts. The two disk surfaces are completely closed and then unfolded to 180°, which is counted as one folding, until the first connection portion 1212 breaks, stop folding, and record the number of folding times.

[0131] The test method for the battery short-circuit rate is: prepare battery samples according to the same positive and negative electrode ratio, process method and parameters, continuously produce 200 pieces, use Hipot equipment to perform short-circuit tests on the 200 pieces of semi-finished batteries obtained, and determine them as defective according to the Hipot value ≤300MΩ to calculate the battery short-circuit defect rate.

[0132] Table 1

[0133]

[0134]

[0135]

[0136] It can be seen from Table 1 that when S2 / S1 is set to 6.6%, W1 / W is set to 50%, L2 / L is set to 50%, L3 / L is set to 6.74%, H is set to 1mm, L1 is set to 3mm, L4 is set to 0.8mm, W2 is set to 2mm, and L5 is set to 1.5mm, the injection time t of the electrolyte is 693 seconds, the maximum temperature T1max at the welding point between the first disk body 110 and the pole 200 is 56.4°C, the maximum temperature T2max at the welding point between the second disk body 120 and the winding core 300 is 68.9°C, the maximum temperature T3max at the fuse slot 130 is 73.6°C, the number of folding times C1 at which the first connecting portion 1211 is broken after being folded in half at the fuse slot 130 is 5 times, the number of folding times C2 at which the second connecting portion 1212 is broken after being folded in half is 5 times, and the battery short circuit rate is only 1%. It can be seen that within the above numerical range, the injection rate, welding temperature rise, structural strength and connection reliability of the positive electrode current collecting disc 100 can be well balanced, thereby effectively improving the safety and charge and discharge performance of the battery and reducing the production cost of the battery.

[0137] It can be seen from Table 1 that if S2 / S1 is too small, H is too small, W1 / W is too large, L2 / L is too small, L3 / L is too small, L4 is too small, L5 is too small, and no fuse slot 130 or notch 150 is provided, the electrolyte injection time t will increase to a certain extent.

[0138] It can be seen from Table 1 that if S2 / S1 is too large, the maximum temperature T1max at the welding point between the first plate 110 and the pole 200 will increase significantly.

[0139] It can be seen from Table 1 that excessively large L2 / L, L3 / L, L4, W2, and L5 will all lead to an increase in the maximum temperature T2max at the welding point between the second disk body 120 and the winding core 300.

[0140] As can be seen from Table 1, if W1 / W is too small, the maximum temperature T3max at the fuse slot 130 will increase significantly. If W1 / W is too large or L1 is too short, the maximum temperature T3max at the fuse slot 130 will be lower. It can be understood that for the location where the fuse slot 130 is located, if the temperature cannot rise to the critical value of the fuse, the first connection portion 1211 cannot be fused in time, and thus the safety protection effect cannot be produced.

[0141] It can be seen from Table 1 that if W1 / W is too small or L1 is too large, the number of folding times C1 at which the first connection portion 1211 is broken after being folded at the fuse slot 130 will be reduced.

[0142] It can be seen from Table 1 that if W2 is too small, the number of folding times C2 at which the second connection portion 1212 breaks after being folded in half will be significantly reduced, and the second connection portion 1212 will be more likely to break.

[0143] It can be seen from Table 1 that if H is too large, the probability of battery short circuit will increase significantly.

[0144] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present implementation. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0145] Although examples of the present embodiment have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present embodiment, and the scope of the present embodiment is defined by the claims and their equivalents.

Claims

1. A positive electrode current collector for a cylindrical lithium-ion battery, characterized in that: The invention comprises a first disk body (110) located at the center and a second disk body (120) connected to the edge of the first disk body (110) and extending radially outward, wherein the first disk body (110) is used for welding with the pole of the cylindrical lithium-ion battery, and the second disk body (120) is used for welding with the winding core of the cylindrical lithium-ion battery. A central hole (111) is provided at the center of the first disk body (110), the area of ​​the first disk body (110) is S1, the area of ​​the central hole (111) is S2, and the range of S2 / S1 is 4.2% to 8.6%.

2. The positive electrode current collecting disk according to claim 1, characterized in that: Along the thickness direction of the positive electrode current collecting disk, the first disk body (110) is higher than the second disk body (120), and the height difference between the surface of the first disk body (110) on the side higher than the second disk body (120) and the surface of the second disk body (110) on the same side is H, and the range of H is 0.6 to 1.4 mm.

3. The positive electrode current collecting disk according to claim 1, characterized in that: The second disk body (120) comprises a connecting portion (121) and a welding portion (122) connected to each other, the welding portion (122) being connected to the edge of the first disk body (110) via the connecting portion (121), and the connecting portion (121) is provided with a fuse groove (130) along its lengthwise edge.

4. The positive electrode current collecting disk according to claim 3, characterized in that: The connecting portion (121) has a first width W, and the connecting portion (121) has a second width W1 in a region where the fuse groove (130) is provided, and the range of W1 / W is 42% to 63%.

5. The positive electrode current collecting disk according to claim 4, characterized in that: The connecting portion (121) has a first edge (131) extending along the length direction for forming the fuse slot (130), and the length of the first edge (131) is L1, and the range of L1 is 2 to 4 mm.

6. The positive electrode current collecting disk according to any one of claims 3 to 5, characterized in that: The connecting portion (121) comprises: a plurality of first connection portions (1211) arranged at intervals along the circumference of the first disk body (110) and extending radially outward from the edge thereof, wherein the fuse slot (130) is provided at the first connection portion (1211); A second connection portion (1212) formed by extending the outer end portions of each of the first connection portions (1211) toward both sides along the circumferential direction; There are multiple welding parts (122), each of which is arranged one by one in an area jointly defined by two adjacent first connecting parts (1211) and the second connecting parts (1212), and is formed by the inner edge of the second connecting part (1212) extending radially inward.

7. The positive electrode current collecting disk according to claim 6, characterized in that: The edges on both sides of the welding portion (122) and the inner edge of the second connecting portion (1212) define a slit (140) extending in the circumferential direction, the circumference of the outer edge of the second connecting portion (1212) is L, the total arc length of the slit (140) is L2, and the range of L2 / L is 43% to 58%.

8. The positive electrode current collecting disk according to claim 7, characterized in that: The second connecting portion (1212) is provided with a plurality of evenly distributed notches (150) at an outer edge corresponding to a position of the welding portion (122); the total arc length of the notches (150) is L3, and the range of L3 / L is 4% to 9%.

9. The positive electrode current collecting disk according to claim 8, characterized in that: The maximum depth of the notch (150) is L5, and the range of L5 is 0.9-2.1 mm.

10. The positive electrode current collecting disk according to claim 6, characterized in that: The width of the slit (140) along the radial direction is L4, and the range of L4 is 0.4-1.5 mm.

11. The positive electrode current collecting disk according to claim 6, characterized in that: The second connection portion (1212) has a width W2 in the radial direction in a region corresponding to the slit (140), and the width W2 is in the range of 1 to 3 mm.

12. A cylindrical lithium-ion battery, characterized in that: A positive electrode current collecting disk (100) comprising any one of claims 1 to 11, further comprising a pole (200), a winding core (300) and a shell (400), wherein the pole (200) is mounted on the shell (400), the winding core (300) is located inside the shell (400), the first disk body (110) in the positive electrode current collecting disk (100) is welded to the pole (200), and the second disk body (120) is welded to the winding core (300).

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