Positive collector plate and cylindrical lithium ion battery

Abstract

The positive collector plate comprises a plate body and a tail body which are connected with each other, the tail body comprises a narrowing area and a main body area in the length direction of the tail body, the narrowing area is connected with the plate body, the narrowing area is located between the main body area and the plate body, and the width of the narrowing area is smaller than that of the main body area in the width direction of the tail body. The narrowing area is connected with the disc body, when the tail body is bent subsequently, the connecting position of the tail body and the disc body is bent firstly, namely, the bent tail body is closer to the center of the disc body, and the situation that the tail body stretches out of the disc body after being reversely bent subsequently for the second time, and entering a shell is affected is avoided. The narrowing area is directly arranged at the root part of the tail body, and the tail body is bent at the root part instead of the middle part of the tail body in the related technology, so that a working procedure is saved, and the implementation of mass production is facilitated. Meanwhile, experimental research finds that compared with the mode that the narrowing area is arranged in the middle of the tail body, the mode that the narrowing area is arranged at the root of the tail body is more beneficial to rapid fusing of the tail body so as to rapidly cut off the current.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of lithium ion batteries, in particular to a positive current collector and a cylindrical lithium ion battery. BACKGROUND

[0002] In the related art, a cylindrical lithium ion battery generally includes a shell, a winding core, a positive current collector, a negative current collector, and a cap. The positive current collector electrically connects the positive electrode of the winding core and the cap, and the negative current collector electrically connects the negative electrode of the winding core and the shell, so that the negative electrode is formed in the shell and the positive electrode is formed in the cap. The positive current collector generally includes a disc body and a tail body connected to each other. The tail body is generally a flat strip of metal and serves as a conductor between the disc body and the cap. In order to cut off the connection between the disc body and the cap in time when a short circuit occurs inside the battery, a groove (narrowing region) is generally provided on the long side of the tail body. The width of the groove is smaller than that of other parts to increase the resistance at the groove, so that the tail body is quickly fused at the groove when a short circuit occurs, thereby playing a safety role. In the related art, the groove is provided in the middle of the tail body. After the positive current collector and the winding core are welded, the tail body needs to be bent twice in opposite directions in a "z" shape. When bent the first time, the groove of the tail body is prone to bending. After the subsequent second reverse bending, the tail body may protrude from the disc body, affecting the subsequent entry of the disc body into the shell. CONTENT OF THE UTILITY MODEL

[0003] The embodiments of the present application provide a positive current collector and a cylindrical lithium ion battery to at least solve the technical problem that the middle of the tail body of the existing positive current collector is prone to bending when bent, which may cause the tail body to protrude from the disc body subsequently.

[0004] The first aspect of the present application provides a positive current collector, which includes a disc body and a tail body connected to each other. The disc body is used to connect with a winding core, and the tail body is used to connect with a cap to form a passage between the winding core and the cap. The tail body includes a narrowing region and a main body region along its length direction. The narrowing region is connected to the disc body and is located between the main body region and the disc body. Along the width direction of the tail body, the width of the narrowing region is smaller than that of the main body region.

[0005] The positive current collector according to the embodiments of the present application has at least the following beneficial effects:

[0006] The positive electrode current collector disc of the embodiment of the present application is connected with the disc body through the narrowing area. When the tail body is subsequently bent, the bending first occurs at the connection between the tail body and the disc body (the root), that is, the bent tail body is closer to the center of the disc body, avoiding the tail body extending out of the disc body after the second reverse bending, which affects the shell entering. In the embodiment, the groove (i.e. the narrowing area) is directly arranged at the root of the tail body. When the tail body is bent, the bending occurs at the root, not in the middle of the tail body in the related art, thereby saving a process and being conducive to mass production. At the same time, through experimental research, it is found that compared with arranging the groove in the middle of the tail body, arranging the groove (narrowing area) in the root of the tail body is more conducive to the rapid melting of the tail body to quickly cut off the current.

[0007] In a possible implementation, the narrowing area and the main body area further comprise a transition area, the transition area is connected with the narrowing area and the main body area respectively, and the width of the transition area gradually decreases in the direction from the main body area to the narrowing area. By arranging the transition area, the connection stress between the narrowing area and the main body area is reduced, and bending or even breaking at the connection between the narrowing area and the main body area during transportation is avoided.

[0008] In a possible implementation, the width of the narrowing area is L1, and the width of the main body area is L2 in the width direction of the tail body, and the range of L1 / L2 is 40% to 60%. By setting the range of L1 / L2 to 40% to 60%, the connection strength between the disc body and the tail body and the melting feature of the tail body are balanced.

[0009] In a possible implementation, the length of the narrowing area is L3, and the length of the tail body is L4 in the length direction of the tail body, and the range of L3 / L4 is 7% to 12%. By setting the range of L3 / L4 to 7% to 12%, the connection strength between the disc body and the tail body and the melting feature of the tail body are balanced.

[0010] In a possible implementation, the narrowing area comprises opposite first and second edges in the width direction of the tail body, the transition area comprises opposite third and fourth edges, the third and fourth edges form an included angle, the distance between the third and fourth edges gradually decreases in the direction from the main body area to the narrowing area, the first edge is connected with the third edge, the second edge is connected with the fourth edge, the first edge and the third edge form an included angle α, and the range of α is 120° to 135°. By setting the range of α to 120° to 135°, the melting feature of the tail body is balanced.

[0011] In a possible implementation, the shape of the disc body is an axisymmetric figure formed by a fifth edge, a circular arc and a sixth edge connected in sequence, the narrowing region includes opposite first and second edges in the width direction of the tail body, the fifth edge is connected with the first edge, the sixth edge is connected with the second edge, the first edge and the fifth edge form an included angle β, and β ranges from 70° to 90°. By setting the range of β to be from 70° to 90°, the connection strength between the disc body and the tail body and the welding effect of the disc body are balanced.

[0012] In a possible implementation, a tangent line at the connection between the circular arc and the fifth edge forms an included angle γ with the fifth edge, and γ ranges from 110° to 120°. By setting the range of γ to be from 110° to 120°, the welding effect of the disc body and the convenience of the positive current collecting disc into the shell are balanced.

[0013] In a possible implementation, the length of the fifth edge is L5, and the radius of the disc body is L6, and the range of L5 / L6 is from 45% to 55%.

[0014] In a possible implementation, the center of the disc body is further provided with a central hole and at least one peripheral hole, the at least one peripheral hole is located at the periphery of the central hole, the diameter of the central hole ranges from 4.5 mm to 5.5 mm, and the diameter of the peripheral hole ranges from 2.5 mm to 3.5 mm, which balances the electrolyte injection efficiency and the structural strength of the disc body.

[0015] The second aspect of the embodiments of the present application provides a cylindrical lithium ion battery, which includes a winding core, a cap and any one of the positive current collecting discs provided in the foregoing embodiments, a positive electrode of the winding core forms a passage with the cap through the positive current collecting disc; wherein the disc body is connected with the winding core, and the tail body is connected with the cap.

[0016] The cylindrical lithium ion battery according to the embodiments of the present application has at least the following beneficial effects:

[0017] By connecting the narrowing region with the disc body, when the tail body is subsequently bent, the bending first occurs at the connection between the tail body and the disc body, that is, the bent tail body is closer to the center of the disc body, avoiding the tail body extending out of the disc body after the subsequent second reverse bending, which affects the entry into the shell. In the embodiment, the groove (i.e., the narrowing region) is directly arranged at the root of the tail body, and the bending occurs at the root when the tail body is bent, rather than at the middle part of the tail body in the related art, thereby saving a process and being conducive to mass production. At the same time, through experimental research, it is found that, compared with arranging the groove (i.e., the narrowing region) at the middle part of the tail body, arranging the groove (narrowing region) at the root of the tail body is more conducive to rapid melting of the tail body to rapidly cut off the current. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the description of the embodiments of the present application will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor based on these drawings.

[0019] Figure 1 is a schematic diagram of a positive current collector disc provided by an embodiment of the present application;

[0020] Figure 2 is Figure 1 is a partial schematic diagram of A in FIG. 1;

[0021] Figure 3 is Figure 1 is a partial schematic diagram of B in FIG. 1;

[0022] Figure 4 is a schematic diagram of a cylindrical lithium ion battery provided by an embodiment of the present application.

[0023] Reference signs:

[0024] 100-positive current collector disc, 110-disc body, 111-fifth side, 112-circular arc, 113-sixth side, 114-tangent, 115-central hole, 116-peripheral hole, 120-tail body, 121-narrowed region, 1211-first side, 1212-second side, 122-main body region, 123-transition region, 1231-third side, 1232-fourth side;

[0025] 200-winding core;

[0026] 300-cap;

[0027] 400-outer shell. DETAILED DESCRIPTION

[0028] Embodiments of the present embodiment will be described in detail below, examples of which are shown in the drawings, wherein the same or similar reference signs represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary and are only used to explain the present embodiment, and cannot be understood as a limitation of the present embodiment.

[0029] In the description of the present embodiment, it should be understood that the orientation description, such as the orientation or position relationship indicated by up, down, front, back, left, right, etc. is based on the orientation or position relationship shown in the drawings, and is only for the convenience of describing the present embodiment and simplifying the description, and therefore cannot be understood as a limitation of the present embodiment.

[0030] In the description of the present embodiment, the meaning of several is one or more, the meaning of multiple is two or more, greater than, less than, more than, etc. are understood as not including the number, above, below, within, etc. are understood as including the number. If it is described as first, 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 indicated technical features or the sequence of indicated technical features.

[0031] In the description of the present embodiment, unless otherwise explicitly limited, the words such as setting, installing, connecting, etc. should be understood broadly, and those skilled in the art can reasonably determine the specific meaning of the above words in the present embodiment in combination with the specific content of the technical solution.

[0032] Please refer to Figure 1 The positive current collector disc 100 provided by the embodiment of the present application comprises a disc body 110 and a tail body 120 connected with each other, the disc body 110 is used to be connected with the winding core 200, and the tail body 120 is used to be connected with the cap 300, so as to form a passage between the winding core 200 and the cap 300. The tail body 120 comprises a narrowing region 121 and a main body region 122 along the length direction of the tail body 120, Figure 1 In the present embodiment, several regions on the tail body 120 are segmented by dashed lines to distinguish them. The narrowing region 121 is connected with the disc body 110, and the narrowing region 121 is located between the disc body 110 and the main body region 122. Along the width direction of the tail body 120, the width of the narrowing region 121 is smaller than the width of the main body region 122. The tail body 120 comprises the narrowing region 121 and the main body region 122 along the length direction of the tail body 120, the narrowing region 121 is connected with the disc body 110, and the narrowing region 121 is located between the main body region 122 and the disc body 110. Along the width direction of the tail body 120, the width of the narrowing region 121 is smaller than the width of the main body region 122. By connecting the narrowing region 121 with the disc body 110, when the tail body 120 is subsequently bent, the bending first occurs at the connection between the tail body 120 and the disc body 110, that is, the bent tail body 120 is closer to the center of the disc body 110, thereby avoiding the tail body 120 extending out of the disc body 110 after the subsequent second reverse bending, and affecting the entry of the positive current collector disc 100 into the shell.

[0033] It can be understood that, in the related art, when the tail body 120 is bent, the bending first occurs at the groove, in order to avoid affecting the entry of the positive current collector disc 100 into the shell, a process of bending the root of the tail body 120 (the connection between the tail body 120 and the disc body 110) is needed, and in the present embodiment, the groove (i.e. the narrowing region 121) is directly arranged at the root of the tail body 120, thereby saving a process and being conducive to mass production.

[0034] Meanwhile, through experimental research, it is found that, compared with setting the groove in the middle of the tail body 120, setting the groove (narrowing area 121) at the root of the tail body 120 is more conducive to the rapid melting of the tail body 120 and the disc body 110. The following describes that the melting time is shorter when the narrowing area 121 is set at the root of the tail body 120 through several schemes of setting the narrowing area 121 at different positions of the tail body 120. The test experiment includes four different positions of the narrowing area 121, which are respectively the narrowing area 121 of the embodiment A of the present application set at the connection between the disc body 110 and the tail body 120, marked as A, and the group includes three test samples, respectively marked as A1, A2 and A3.

[0035] Embodiment A: along the width direction of the tail body 120, the width of the narrowing area 121 is L1, and the width of the main body area 122 is L2; along the length direction of the tail body 120, the length of the narrowing area 121 is L3, and the length of the tail body 120 is L4; along the width direction of the tail body 120, the narrowing area 121 includes opposite first and second edges 1211 and 1212, and the narrowing area 121 and the main body area 122 further include a transition area 123 connected with the narrowing area 121 and the main body area 122, respectively, and the width of the transition area 123 gradually decreases in the direction from the main body area 122 to the narrowing area 121, the transition area 123 includes opposite third and fourth edges 1231 and 1232, the first edge 1211 is connected with the third edge 1231, and the second edge 1212 is connected with the fourth edge 1232, and the first edge 1211 and the third edge 1231 form an included angle α; the disc body 110 is in the shape of an axisymmetric figure formed by a fifth edge 111, a circular arc 112 and a sixth edge 113 connected in sequence, the fifth edge 111 is connected with the first edge 1211, and the first edge 1211 and the fifth edge 111 form an included angle β; the tangent line 114 of the circular arc 112 at the connection with the fifth edge 111 forms an included angle γ with the fifth edge 111; the length of the fifth edge 111 is L5, and the radius of the disc body 110 is L6; the center of the disc body 110 is further provided with a center hole 115 and at least one peripheral hole 116, and the at least one peripheral hole 116 is located at the periphery of the center hole 115; wherein L1 is 3 mm, L2 is 5 mm, L3 is 1.5 mm, L4 is 15 mm, the included angle α is 130°, the included angle β is 80°, the included angle γ is 112°, L5 is 4.5 mm, L6 is 9.1 mm, the diameter of the center hole 115 is 5 mm, and the diameter of the peripheral hole 116 is 3 mm.

[0036] The narrowing areas 121 of the remaining three groups are set with reference to the narrowing area parameters of embodiment A, and the difference lies in that the positions of the remaining three groups of narrowing areas are different, which are respectively set at the middle of the tail body 120 close to the disc body 110 (B), the middle of the tail body 120 (C) and the middle of the tail body 120 away from the disc body 110 (D). The specific setting positions are as follows:

[0037] Embodiment B: the narrowed region 121 is arranged at the middle of the tail body 120 close to the disc body 110 (B), specifically, at 1 / 4 of the tail body 120 close to the disc body 110.

[0038] Embodiment C: the narrowed region 121 is arranged at 1 / 2 of the middle of the tail body 120.

[0039] Embodiment D: the narrowed region 121 is arranged at the middle of the tail body 120 far away from the disc body 110 (D), specifically, at 3 / 4 of the tail body 120 far away from the disc body 110.

[0040] Similarly, each group includes 3 test samples, respectively recorded as B1, B2 and B3; C1, C2 and C3; D1, D2 and D3. The test method is to apply different intensity of current (unit: ampere / A) to the sample, and record the melting time (unit: second / S) of the narrowed region 121. Table 1 below is the test record table.

[0041] Table 1

[0042]

[0043] As can be seen from Table 1, under different intensity of current, arranging the narrowed region 121 at the connection between the disc body 110 and the tail body 120 can reduce the melting time of the narrowed region 121, thereby improving the safety of the cylindrical lithium ion battery.

[0044] In the embodiments of the present application, the connection between the disc body 110 and the winding core 200, and the connection between the tail body 120 and the disc body 110 can adopt any connection mode known to those skilled in the art, for example, welding. The connection between the tail body 120 and the disc body 110 can be any fixed connection mode, and in order to ensure the stability of the connection and the overall strength of the current collecting disc, the preferred connection mode is integral connection.

[0045] In the embodiments of the present application, the narrowed region 121 is formed by inwardly recessing the long side of the tail body 120 along the width direction of the tail body 120, that is, the tail body 120 further includes a groove at the narrowed region 121 of the tail body 120. It can be understood that the groove can be arranged on one long side of the tail body 120, or the grooves are arranged on both long sides of the tail body 120, and the arrangement positions correspond to each other. In the production process, according to the size of the groove, the material of the tail body 120 is cut off at the connection between the tail body 120 and the disc body 110 to form the groove, thereby obtaining the narrowed region 121.

[0046] Further, please continue to refer to Figure 1, the narrowed region 121 and the main body region 122 further comprise a transition region 123, the transition region 123 is connected with the narrowed region 121 and the main body region 122 respectively, and the width of the transition region 123 gradually decreases in the direction from the main body region 122 to the narrowed region 121. By setting the transition region 123, the connection stress between the narrowed region 121 and the main body region 122 is reduced, and the bending or even breaking of the connection between the narrowed region 121 and the main body region 122 during transportation is avoided. It can be understood that if the narrowed region 121 is provided with a groove only on one long side of the tail body 120, correspondingly, one long side of the tail body 120 is inclined at the transition region 123 from the main body region 122 to the narrowed region 121, that is, the long side of the tail body 120 is a bevel at the transition region 123. It can be understood that if the narrowed region 121 is provided with a groove on both long sides of the tail body 120, correspondingly, both long sides of the tail body 120 are inclined at the transition region 123 from the main body region 122 to the narrowed region 121, that is, both long sides of the tail body 120 are bevels at the transition region 123.

[0047] Further, please refer to Figure 2 , along the width direction of the tail body 120, the width of the narrowed region 121 is L1, the width of the main body region 122 is L2, and the range of L1 / L2 is 40% to 60%. According to actual needs, the ratio of L1 / L2 can be 40%, 45%, 50%, 55% or 60%. If L1 / L2 is less than 40%, the width of the narrowed region 121 is relatively narrow, and when the tail body 120 of the positive current collector 100 is bent, the narrowed region 121 is easy to break, thereby increasing the cost of manufacturing cylindrical lithium ion batteries. If L1 / L2 is greater than 60%, the current flowing through the narrowed region 121 is not easy to converge during charging and discharging of the cylindrical lithium ion battery, thereby making the narrowed region 121 not easy to melt and break, and it is difficult to ensure the safety of the cylindrical lithium ion battery. By setting the range of L1 / L2 to 40% to 60%, the connection strength between the disc body 110 and the tail body 120 and the melting and breaking characteristics of the tail body 120 are balanced.

[0048] Further, please refer to Figure 1 and Figure 2, along the length direction of the tail body 120, the length of the narrowed region 121 is L3, the length of the tail body 120 is L4, the range of L3 / L4 is 7%~12%, according to actual needs, the ratio of L3 / L4 can be 7%, 10% or 12%. If L3 / L4 is less than 7%, the length of the narrowed region 121 is too short, if the narrowed region 121 is too short, the corresponding resistance value is higher at this point, the cylindrical lithium ion battery may be fused during normal charging and discharging, thereby affecting the actual use of the cylindrical lithium ion battery. If L3 / L4 is greater than 12%, the length of the narrowed region 121 is too long, the overcurrent of the narrowed region 121 is not easy to converge during charging and discharging of the cylindrical lithium ion battery, thereby making the narrowed region 121 not easy to fuse, and it is difficult to ensure the safety of the cylindrical lithium ion battery. By setting the range of L3 / L4 to be 7%~12%, it is helpful to balance the connection strength between the disc body 110 and the tail body 120 and the fusing characteristics of the tail body 120.

[0049] Further, along the width direction of the tail body 120, the narrowed region 121 includes opposite first and second edges 1211 and 1212, the transition region 123 includes opposite third and fourth edges 1231 and 1232, the third and fourth edges 1231 and 1232 form an included angle, the distance between the third and fourth edges 1231 and 1232 gradually decreases in the direction from the main body region 122 to the narrowed region 121, the first edge 1211 is connected to the third edge 1231, and the second edge 1212 is connected to the fourth edge 1232, the first edge 1211 and the third edge 1231 form an included angle α, the range of α is 120°~135°, according to actual needs, the range of α can be 120°, 125°, 130° or 135°. If α is less than 120°, the current flows out of the narrowed region 121 faster, which is not conducive to heat collection and fusing of the narrowed region 121; if α is greater than 135°, the difference between the connection of the narrowed region 121 and the main body region 122 is reduced, the heat is not concentrated, resulting in a long fusing time, which is not conducive to ensuring the safety of the cylindrical lithium ion battery. By setting the range of α to be 120°~135°, it is helpful to balance the fusing characteristics of the tail body 120.

[0050] It can be understood that the first edge 1211 and the second edge 1212 of the narrowing region 121 are corresponding, the third edge 1231 and the fourth edge 1232 of the transition region 123 can be both bevels, or one of the third edge 1231 and the fourth edge 1232 is a bevel and the other is a straight edge parallel to the length direction of the tail body 120, and the bevel of the transition region 123 makes the width of the transition region 123 in the width direction of the tail body 120 gradually decrease from the main body region 122 to the narrowing region 121, which depends on the number of grooves of the narrowing region 121. It can be understood that the angle formed by the third edge 1231 and the fourth edge 1232 means that the extension lines of the third edge 1231 and the fourth edge 1232 intersect, so that the distance between the third edge 1231 and the fourth edge 1232 of the transition region 123 gradually changes.

[0051] Further, referring to Figure 1 and Figure 2 , the shape of the disc body 110 is an axisymmetric figure formed by the fifth edge 111, the circular arc 112 and the sixth edge 113 connected in sequence, and along the width direction of the tail body 120, the narrowing region 121 includes opposite first edge 1211 and second edge 1212, the fifth edge 111 is connected with the first edge 1211, the sixth edge 113 is connected with the second edge 1212, the first edge 1211 and the fifth edge 111 form an angle β, and the range of β is 70°-90°. According to actual needs, β can be 70°, 75°, 80°, 85° or 90°. If β is greater than 90°, the area of the disc body 110 part needs to be reduced accordingly to maintain a large angle of β while keeping the first edge 1211 unchanged, which will lead to the reduction of the area of the disc body 110, thereby reducing the welding area between the subsequent disc body 110 and the winding core 200, and affecting the welding effect. If β is less than 70°, the angle between the first edge 1211 and the fifth edge 111 is too small, which will lead to excessive stress between the first edge 1211 and the fifth edge 111, and the tail body 120 is easy to be torn or even broken under a large stress when it is bent. By setting the range of β to be 70°-90°, it is helpful to balance the connection strength between the disc body 110 and the tail body 120 and the welding effect of the disc body 110.

[0052] Further, the connection between the first edge 1211 and the fifth edge 111, and the connection between the second edge 1212 and the sixth edge 113 also includes a round chamfer, which helps to alleviate the stress between them. Further, the mutual relationship between the second edge 1212 and the sixth edge 113 is the same as that between the first edge 1211 and the fifth edge 111, which will not be described here.

[0053] Further, referring to Figure 1 and Figure 3, the tangent line 114 at the connection of the fifth side 111 and the circular arc 112 forms an angle γ with the fifth side 111, and the range of γ is 110°-120°. According to actual needs, the angle γ can be 110°, 112°, 115°, 117° or 120°. If the angle γ is too small, the connection between the tail body 120 and the disc body 110 is closer to the center of the disc body 110, resulting in a smaller area of the disc body 110, which is not conducive to the welding of the disc body 110 and the winding core 200. If the angle γ is too large, the connection area between the disc body 110 and the tail body 120 is limited, and after the tail body 120 is bent, the tail body 120 may protrude out of the disc body 110, affecting the subsequent entry of the disc body 110 into the shell 400. By setting the range of γ to be 110°-120°, the welding effect of the disc body 110 and the convenience of the positive current collecting disc 100 into the shell can be balanced.

[0054] Further, the length of the fifth side 111 is L5, and the radius of the disc body 110 is L6, and the range of L5 / L6 is 45%-55%. According to actual needs, L5 / L6 can be 45%, 50% or 55%. If L5 / L6 is less than 45%, the length of the fifth side 111 is too short, which will result in a too small area of the entire disc body 110, which is not conducive to the subsequent welding of the disc body 110 and the winding core 200. If L5 / L6 is greater than 55%, the length of the fifth side 111 is too long, and the fifth side 111 may touch the shell 400 and cause a short circuit.

[0055] Further, the angle of the circular arc 112 of the disc body 110 is greater than 180°, and the further range is 210°-300°. If the angle of the circular arc 112 is too small, the area of the entire disc body 110 will be too small, which is not conducive to the welding of the disc body 110 and the winding core 200. If the angle of the circular arc 112 is too large, the connection area between the disc body 110 and the tail body 120 is limited, and after the tail body 120 is bent, the tail body 120 may protrude out of the disc body 110, affecting the subsequent entry of the disc body 110 into the shell 400.

[0056] Further, the center of the disc body 110 is also provided with a center hole 115 and at least one peripheral hole 116, and the at least one peripheral hole 116 is located on the periphery of the center hole 115. The diameter of the center hole 115 ranges from 4.5 to 5.5 mm, and the diameter of the peripheral hole 116 ranges from 2.5 to 3.5 mm, which helps to balance the electrolyte injection efficiency and the structural strength of the disc body 110. In the production process of the cylindrical lithium ion battery, after the combination of the welded winding core 200 and the disc body 110 is loaded into the shell 400, electrolyte needs to be injected into the shell 400. By providing a center hole 115 in the center of the disc body 110, the electrolyte injection is facilitated. It can be understood that the center hole 115 is a circular hole, and the size of the center hole 115 can be selected according to the demand for electrolyte injection speed.

[0057] Further, the center hole 115 is further provided with at least one peripheral hole 116, which can assist in electrolyte filling and can also play a role in rapid exhaust to avoid the accumulation of internal pressure of the battery to cause explosion or damage. Further, the number of peripheral holes 116 is three, which helps to balance the structural strength of the disc body 110 and the efficiency of liquid injection and exhaust. Further, the center hole 115 and the peripheral hole 116 are both circular holes, which are convenient for processing, and the diameter of the center hole 115 is greater than that of the peripheral hole 116, so as to balance the safety of welding and the efficiency of liquid injection.

[0058] Please refer to Figure 4 The application further provides a cylindrical lithium ion battery, which comprises the positive current collector disc 100, the cap 300 and the winding core 200, the positive electrode of the winding core 200 passes through the positive current collector disc 100 to form a passage with the cap 300; wherein the disc body 110 is connected with the winding core 200, and the tail body 120 is connected with the cap 300. In the positive current collector disc 100, the narrowed region 121 is arranged at the connection between the disc body 110 and the tail body 120, so that a process is saved in the subsequent bending process of the tail body 120, which is helpful for mass production; at the same time, the narrowed region 121 arranged at the connection between the disc body 110 and the tail body 120 brings the benefit of shorter melting time, which guarantees the safety of the cylindrical lithium ion battery.

[0059] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "exemplary embodiment", "example", "specific example" or "some examples" means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present embodiment. In the present specification, the exemplary description of the above terms does not necessarily mean the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0060] Although the embodiments of the present embodiment have been shown and described, those skilled in the art can understand that various changes, modifications, replacements and variations can be made to the embodiments without departing from the principles and purposes 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, It includes a disk (110) and a tail (120) connected to each other. The disk (110) is used to connect to the core (200) of the cylindrical lithium-ion battery, and the tail (120) is used to connect to the cap (300) of the cylindrical lithium-ion battery, so that a passage is formed between the core (200) and the cap (300). The tail body (120) includes a narrowing region (121) and a main body region (122) along its length direction. The narrowing region (121) is connected to the disc body (110) and is located between the main body region (122) and the disc body (110). Along the width direction of the tail body (120), the width of the narrowing region (121) is smaller than the width of the main body region (122).

2. The positive current collector according to claim 1, characterized in that, The narrowing region (121) and the main body region (122) are further connected by a transition region (123). The transition region (123) is connected to the narrowing region (121) and the main body region (122) respectively. The width of the transition region (123) gradually decreases along the direction from the main body region (122) to the narrowing region (121).

3. The positive current collector according to claim 2, characterized in that, Along the width direction of the tail (120), the width of the narrowing region (121) is L1, and the width of the main body region (122) is L2, with L1 / L2 ranging from 40% to 60%.

4. The positive current collector according to claim 2, characterized in that, Along the length direction of the tail body (120), the length of the narrowing region (121) is L3, the length of the tail body (120) is L4, and the range of L3 / L4 is 7% to 12%.

5. The positive current collector according to claim 2, characterized in that, Along the width direction of the tail body (120), the narrowing region (121) includes a first side (1211) and a second side (1212) opposite each other, and the transition region (123) includes a third side (1231) and a fourth side (1232) opposite each other. The third side (1231) and the fourth side (1232) form an angle. Along the direction from the main body region (122) to the narrowing region (121), the distance between the third side (1231) and the fourth side (1232) gradually decreases. The first side (1211) is connected to the third side (1231), and the second side (1212) is connected to the fourth side (1232). The first side (1211) and the third side (1231) form an angle α, and the range of α is 120° to 135°.

6. The positive current collector according to claim 1, characterized in that, The disc body (110) is an axisymmetric figure formed by connecting the fifth side (111), the arc (112) and the sixth side (113) in sequence. Along the width direction of the tail body (120), the narrowing area (121) includes a first side (1211) and a second side (1212) opposite each other. The fifth side (111) is connected to the first side (1211), and the sixth side (113) is connected to the second side (1212). The first side (1211) and the fifth side (111) form an included angle β, and the range of β is 70° to 90°.

7. The positive current collector according to claim 6, characterized in that, The tangent (114) of the arc (112) at the point where it connects with the fifth side (111) forms an angle γ with the fifth side (111), where γ ranges from 110° to 120°.

8. The positive current collector according to claim 6, characterized in that, The length of the fifth side (111) is L5, the radius of the disk (110) is L6, and the ratio of L5 to L6 is in the range of 45% to 55%.

9. The positive current collector according to claim 1, characterized in that, The center of the disc body (110) is also provided with a central hole (115) and at least one peripheral hole (116). The at least one peripheral hole (116) is located on the periphery of the central hole (115). The diameter of the central hole (115) is in the range of 4.5 to 5.5 mm, and the diameter of the peripheral hole (116) is in the range of 2.5 to 3.5 mm.

10. A cylindrical lithium-ion battery, characterized in that, The device includes a core (200), a cap (300), and a positive current collector as described in any one of claims 1-9, wherein the positive electrode of the core (200) forms a passage with the cap (300) through the positive current collector; wherein the disk body (110) is connected to the core (200), and the tail body (120) is connected to the cap (300).

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