Cathode collector plate and cylindrical lithium battery

Abstract

The utility model provides a negative collector plate and a cylindrical lithium battery. The negative current collecting disc is used for conducting connection between a metal shell and a roll core pole group and comprises a circular disc body, the diameter of the disc body is D1, the diameter of the roll core pole group is D2, D1 / D2 = 90%-98%, the disc body is provided with a first end side and a second end side which are deviated from each other, the disc body is provided with a boss with a flat surface in the central area of the first end side, and the boss is provided with a first electrode and a second electrode. The surface of the boss is higher than the surface of the first end side, the surface area of the boss is smaller than the surface area of the first end side, and the surface of the boss is suitable for abutting against the inner surface of the shell bottom of the metal shell. As the boss with smaller area and flat surface is arranged on the first end side of the negative collector plate, the surface of the boss can be well attached to the inner surface of the bottom of the metal shell, reliable surface-to-surface contact connection can be formed between the boss and the inner surface of the bottom of the metal shell, and the electric connection effect is good. The battery using the negative collector plate has better performance and yield.

Description

Technical Field

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

[0002] According to the packaging form, lithium batteries can be divided into three forms: square, cylindrical and soft-pack. Among them, cylindrical lithium batteries have gradually become a hot spot in lithium battery research due to their good consistency, high production efficiency, and strong heat dissipation capacity at the system level. They have been promoted and applied in electric vehicles, energy storage and other fields.

[0003] In the related art, a cylindrical lithium battery with a full-ear structure includes a metal shell, a core electrode group, and a cap, among which the core electrode group is cylindrical, and the positive and negative electrode ears are flattened to form round and flat end faces at both ends. Therefore, a positive collector plate and a negative collector plate can be added to the positive and negative electrodes respectively. The full-ear structure and the addition of positive and negative collector plates allow electrons to be transmitted longitudinally from the collector to the collector plate, which can effectively improve the charge and discharge performance of the cylindrical lithium battery by increasing the current conduction area and shortening the current conduction distance. However, the negative electrode current collector disk needs to be welded to the core electrode group and the metal shell respectively. Therefore, in order to increase the welding area between the negative electrode current collector disk and the metal shell and the core electrode group, and at the same time increase the current conduction area, it is possible to consider increasing the diameter of the negative electrode current collector disk. However, when the diameter of the negative electrode current collector disk is larger, the flatness of its surface will deteriorate. Therefore, it is difficult to ensure that the negative electrode current collector disk can fit well with the metal shell. In the case of poor fit between the two, there is a risk of cold welding after welding, which will further cause defects such as short circuit of the lithium battery and inability to work normally. Utility Model Content

[0004] In order to solve the above problems, an embodiment of the present application provides a negative electrode current collector disc, which can achieve reliable contact connection with the metal shell of the cylindrical lithium battery to improve the electrical connection effect between the two.

[0005] The present application also provides a cylindrical lithium battery using the above-mentioned negative electrode current collector.

[0006] In a first aspect, an embodiment of the present application provides a negative electrode current collector for conductive connection between a metal shell and a wound core electrode group, comprising:

[0007] A disk body, wherein the disk body is circular, and the diameter of the disk body is D1, the diameter of the winding core pole group is D2, and the following conditions are satisfied: D1 / D2=90% to 98%, the disk body has a first end side and a second end side which are away from each other, and the second end side is used to be connected to the winding core pole group;

[0008] Among them, the disk body is provided with a flat boss on the first end side, the surface of the boss is higher than the surface of the first end side, and the surface area of ​​the boss is smaller than the surface area of ​​the first end side, and the surface of the boss is suitable for abutting against the inner surface of the bottom of the metal shell.

[0009] The negative electrode current collector according to the first aspect of the embodiment of the present application has at least the following beneficial effects:

[0010] Since the diameter of the negative electrode collector disk is set to match the diameter of the core electrode group, the weldable area between the negative electrode collector disk and the core electrode group is greatly improved, the welding processability is good, and the current conduction area is large. At the same time, a boss with a smaller area and a flat surface is provided on the first end side of the negative electrode collector disk. The surface of the boss as the top surface of the first end side can fit well with the inner surface of the shell bottom of the metal shell, and a reliable surface-to-surface contact connection can be formed between the two, and the electrical connection effect is good.

[0011] Furthermore, when the two are welded together by laser transmission, for example, welding quality problems such as cold welding between the two can be effectively avoided, and the battery using the negative electrode collector has better performance and yield rate.

[0012] In a possible implementation, the height difference between the surface of the boss and the surface of the first end side is H, and the thickness of the disk is T, which satisfies: H / T = 18% to 30%. If the boss is set too high, that is, H / T is too large, the winding core electrode group will squeeze and deform the periphery of the disk during assembly, and will also occupy additional longitudinal space of the battery; if the boss is set too low, that is, H / T is too small, the boss will be difficult to process.

[0013] In a possible implementation, the boss is located in the central area of ​​the first end side. After being assembled into the metal shell, the boss can be aligned with the central area of ​​the bottom of the metal shell, making it convenient to weld the metal shell and the boss by welding equipment.

[0014] In a possible implementation, the boss is circular, and the diameter of the boss is d, satisfying d / D1=28% to 38%. The boss is set to be circular, which is convenient for welding the metal shell and the boss by welding equipment. At the same time, if the diameter d of the boss is too small, it is easy to desolder during welding; conversely, if the diameter d of the boss is too large, its surface flatness will deteriorate, and its fit with the inner surface of the shell bottom will be poor.

[0015] In a possible implementation manner, the boss is integrally formed by stamping the disc body. The boss is stamped, which is easy to process, has low cost, high dimensional accuracy and good surface quality.

[0016] In a possible implementation, a recess is formed on the second end side at a position corresponding to the boss, and a welding area is formed on the second end side around the recess, wherein a surface of the welding area is suitable for abutting against an end surface of the winding core pole group.

[0017] In a possible implementation, the flatness of the boss surface is 0.01-0.05 mm. If the boss surface flatness is too large, the fit between the boss and the inner surface of the shell bottom will be poor; conversely, if the boss surface flatness is too small, it will be difficult to process and the cost will be too high.

[0018] In a possible implementation, the surface of the disc body is plated with a nickel layer, and the thickness of the nickel layer is 0.08 to 1.5 μm. By using the nickel plating layer, the nickel content in the negative electrode current collector can be reduced, and while ensuring the oxidation resistance, the resistance of the negative electrode current collector can be effectively reduced, which is beneficial to improving battery performance.

[0019] In a possible implementation, the disc body is made of copper. By using copper as the base material, the disc body has the characteristic of extremely low internal resistance.

[0020] A second aspect of an embodiment of the present application proposes a cylindrical lithium battery, comprising a metal shell, in which a core electrode group and the negative electrode current collector disk of the first aspect are arranged, the boss of the negative electrode current collector disk is abutted and connected to the inner surface of the shell bottom of the metal shell, and the second end side of the negative electrode current collector disk is abutted and connected to the core electrode group.

[0021] The cylindrical lithium battery according to the second aspect of the embodiment of the present application has at least the following beneficial effects:

[0022] Since the negative electrode current collecting disk has the beneficial effects as described above, the cylindrical lithium battery provided in the present application has better performance and yield rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] 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.

[0024] Figure 1 It is a cross-sectional schematic diagram of the structure after the negative electrode current collector, the metal shell and the core-wound electrode group are welded according to an embodiment of the present application;

[0025] Figure 2 yes Figure 1 The local schematic diagram of the A in the middle;

[0026] Figure 3is a structural schematic diagram of the first end side of the negative electrode current collector provided in an embodiment of the present application;

[0027] Figure 4 yes Figure 3 A schematic cross-sectional view of the middle negative electrode current collector;

[0028] Figure 5 yes Figure 4 Partial schematic diagram of point B in the middle.

[0029] Reference numerals:

[0030] 10-metal shell, 11-side wall, 12-shell bottom, 121-shell bottom inner surface, 122-shell bottom outer surface; 13-inner cavity;

[0031] 20- wound core pole group, 21- end surface;

[0032] 30 - negative electrode current collecting disk, 31 - disk body, 311 - first end side, 3111 - boss, 312 - second end side, 3121 - recessed portion, 3122 - welding area. DETAILED DESCRIPTION

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] In the related art, a cylindrical lithium battery with a full-ear structure includes components such as a metal shell, a core electrode group, and a cap, wherein the core electrode group is cylindrical, and the positive and negative electrode ears are flattened to form circular and flat end faces at both ends. Therefore, a positive electrode collector and a negative electrode collector can be added to the positive and negative electrodes, respectively. Specifically, on the positive electrode side, the end face formed by the flattened ear is welded to the positive electrode collector, and the positive electrode collector is welded to the cap, thereby forming a passage between the core electrode group, the positive electrode collector, and the cap; on the negative electrode side, the end face formed by the flattened ear is welded to the negative electrode collector, and the negative electrode collector is welded to the metal shell, thereby forming a passage between the core electrode group, the negative electrode collector, and the metal shell, and finally forming a positive electrode and a negative electrode outside the battery to provide power to electrical equipment.

[0038] It is understandable that the full-ear structure and the addition of positive and negative current collectors enable electrons to be transmitted longitudinally from the current collector to the current collector, thereby increasing the current conduction area and shortening the current conduction distance, thereby effectively improving the charge and discharge performance of the cylindrical lithium battery. However, as for the negative current collector, it needs to be welded to the core electrode group and the metal shell respectively. Therefore, in order to increase the welding area between the negative current collector and the metal shell and the core electrode group, and at the same time increase the current conduction area, it is possible to consider increasing the diameter of the negative current collector. However, when the diameter of the negative current collector is large, the flatness of its surface will deteriorate. Therefore, it is difficult to ensure that the negative current collector can fit well with the metal shell. In the case of poor fit between the two, the risk of cold welding is prone to occur after the two are welded, which will further cause defects such as short circuits in the lithium battery and inability to work normally.

[0039] The following combination Figures 1 to 5 The negative electrode current collecting disk and the cylindrical lithium battery according to the embodiments of the present application are described in detail.

[0040] refer to Figure 1 and Figure 2 , a negative electrode collector disc 30 of an embodiment of the present application is used for a cylindrical lithium battery, especially a large cylindrical lithium battery with a full-ear structure, such as a 21 series (cylindrical lithium battery with an outer diameter of 21 mm) and a 46 series (cylindrical lithium battery with an outer diameter of 46 mm) battery. In such cylindrical lithium batteries, the negative electrode collector disc 30 is used for conductive connection between the metal shell 10 and the core-wound electrode group 20, that is, to form a path between the core-wound electrode group 20, the negative electrode collector disc 30 and the metal shell 10.

[0041] It is understandable that, in addition to the negative electrode current collector 30, the metal shell 10, the core electrode group 20 and other components, the cylindrical lithium battery also includes other components such as the positive electrode current collector and the cap (not shown in the figure).

[0042] like Figure 1 and Figure 2 As shown, the metal shell 10 is cylindrical as a whole and is open at the positive terminal side. It includes an annular side wall 11 and a shell bottom 12 located at the bottom. The side wall 11 and the shell bottom 12 together define an inner cavity 13. The shell bottom 12 is in the shape of a circular sheet and has a shell bottom inner surface 121 and a shell bottom outer surface 122 that are separated from each other. The shell bottom inner surface 121 and the shell bottom outer surface 122 are both planes, wherein the shell bottom inner surface 121 is located on the side facing the inner cavity 13. In some embodiments, the metal shell 10 can be a nickel-plated steel shell, which has the advantages of high compressive strength, etc., of course, it is not limited to this.

[0043] like Figure 1 and Figure 2 As shown, the wound electrode group 20 formed by winding the positive electrode sheet, the negative electrode sheet and the separator is cylindrical, and in order to smoothly enter the inner cavity 13 of the metal shell 10 through the opening, its diameter is slightly smaller than the inner diameter of the metal shell 10. After the positive and negative pole ears of the wound electrode group 20 are flattened, circular end faces 21 with flat cross sections are formed at both ends. The upper end face 21 is the positive electrode of the wound electrode group 20, which is used for welding with the positive electrode collector, and the lower end face 21 is the negative electrode of the wound electrode group 20, which is used for connecting with the negative electrode collector 30.

[0044] like Figure 1 and Figure 2 As shown, the negative electrode current collector 30 includes a disc body 31, which is circular, and the diameter of the disc body 31 is D1, and the diameter of the core pole group 20 is D2, satisfying D1 / D2=90% to 98%. In this embodiment, the ratio of the diameter D1 of the disc body 31 to the diameter D2 of the core pole group 20 is 90% to 98%, so that the diameter D1 of the disc body is as close as possible to the diameter D2 of the core pole group 20, thereby greatly increasing the welding area between it and the core pole group 20, so as to adapt to various welding shapes and sizes, facilitate the design of welding jigs, and reduce manufacturing costs.

[0045] It can be understood that, for the disc body 31, along the axial direction (thickness direction) of the disc body 31, the disc body 31 has a first end side 311 and a second end side 312 that are separated from each other. Since the first end side 311 is provided with a boss 3111 described below, the first end side 311 and the second end side 312 are strictly distinguished in direction when being welded with the metal shell 10 and the winding core pole group 20. Figure 1 and Figure 2Specifically, the first end side 311 is welded to the metal shell 10 through the boss 3111, and the second end side 312 is welded to the core pole group 20, thereby realizing the welding connection between the core pole group 20, the negative electrode collector disk 30 and the metal shell 10, and a passage is formed between the three, that is, the negative electrode collector disk 30 indirectly connects the core pole group 20 and the metal shell 10 to optimize the flow path of electrons.

[0046] like Figure 1 and Figure 2 As shown, in this embodiment, the disk body 31 is provided with a boss 3111 with a flat surface on the first end side 311, the surface of the boss 3111 is higher than the surface of the first end side 311, and the surface area of ​​the boss 3111 is smaller than the surface area of ​​the first end side 311, and the surface of the boss 3111 is suitable for abutting against the inner surface 121 of the shell bottom of the metal shell 10. It can be understood that, since the surface of the boss 3111 is higher than the surface of the first end side 311, that is, the surface of the boss 3111 is the top surface of the first end side 311, after the negative electrode current collecting plate 30 is assembled into the metal shell 10, the surface of the boss 3111 will abut against the inner surface 121 of the bottom of the metal shell 10, that is, the surface of the boss 3111 and the inner surface 121 of the shell bottom of the metal shell 10 are tightly fitted to each other, and a surface-to-surface contact connection is formed between the two, and then the overlapping area of ​​the boss 3111 and the shell bottom 12 can be laser-welded through the outer surface 122 of the shell bottom, so that the boss 3111 is welded to the metal shell 10.

[0047] In the present embodiment, since the diameter of the negative electrode current collecting disk 30 is set to match the diameter of the core electrode group 20, the weldable area between the negative electrode current collecting disk 30 and the core electrode group 20 is greatly improved, and the welding processability is good. At the same time, a smaller boss 3111 is set on the first end side 311 of the negative electrode current collecting disk 30. Since the boss 3111 has a smaller area, it can ensure that it has good surface flatness during the processing process, so that the surface of the boss 3111 can better fit the inner surface 121 of the shell bottom of the metal shell 10, and can effectively avoid welding quality problems such as cold welding between the two. The battery using the negative electrode current collecting disk 30 has better performance and yield rate.

[0048] The welding process of the negative electrode current collecting disc 30 , the wound electrode group 20 and the metal shell 10 is described in detail below.

[0049] First, the negative electrode current collector disc 30 is welded to the core electrode group 20. In this process, the core electrode group 20 and the negative electrode current collector disc 30 can be positioned by a jig so that the second end side 312 of the disc body 31 abuts against the end face 21 of the core electrode group 20, that is, the surface of the second end side 312 of the disc body 31 fits the surface of the end face 21 of the core electrode group 20, and then the disc body 31 and the core electrode group 20 can be welded and connected by laser penetration welding, so that the negative electrode current collector disc 30 and the core electrode group 20 are welded to form a combination.

[0050] Secondly, the assembly obtained in the previous step is welded to the metal shell 10. In this process, the assembly formed by welding the negative electrode current collector 30 and the core-wound pole group 20 is first placed in the inner cavity 13 of the metal shell 10 with one end open, and is positioned by a jig so that the boss 3111 protruding from the first end side 311 abuts against the inner surface 121 of the shell bottom of the metal shell 10, that is, the surface of the boss 3111 fits with the inner surface 121 of the shell bottom of the metal shell 10, and then the boss 3111 can be welded to the shell bottom 12 at the outer surface 122 of the shell bottom of the metal shell 10 by laser penetration welding, so that the assembly formed by welding the negative electrode current collector 30 and the core-wound pole group 20 is further combined with the metal shell 10 to form a whole, which is further used in subsequent processes.

[0051] It should be noted that although the above description takes the example of the negative electrode current collector being connected to the core electrode group 20 and the metal shell 10 by welding, it is not limited to this. For example, the core electrode group 20, the negative electrode current collector 30, and the shell bottom 12 of the metal shell 10 can also be tightly contacted and connected through an assembly process to achieve electrical conduction, thereby omitting the welding step.

[0052] For the purpose of facilitating processing and reducing costs, in some embodiments, the boss 3111 is formed by the disc body 31 through a stamping process, that is, the boss 3111 is formed integrally with the disc body 31. Therefore, through a reasonable stamping die design, the negative electrode collector disc 30 of this embodiment can be efficiently processed, and the disc body 31 and the boss 3111 have high dimensional accuracy and good surface quality, which facilitates welding with the winding core pole group 20 and the metal shell 10. Of course, it is not limited to this, and the boss 3111 can also be formed in other ways. For example, the boss 3111 can be a sheet metal component with excellent welding performance and conductive performance, and the metal component can be combined with the surface of the first end side 311 of the disc body 31 by pressing, so as to form the boss 3111.

[0053] like Figure 3As shown, in some embodiments, the boss 3111 is formed in the central area of ​​the first end side 311, so that after the negative electrode current collecting plate 30 is assembled into the metal shell 10, the boss 3111 can be aligned with the central area of ​​the shell bottom 12, which facilitates welding the metal shell 10 and the boss 3111 by welding equipment.

[0054] Further, the shape of the boss 3111 is circular, so that the boss 3111 can be arranged co-centrically with the disc body 31, which is convenient for stamping by a stamping die. Of course, the shape of the boss 3111 is not limited to a circle, for example, the boss 3111 can also be a square, a triangle, etc.

[0055] like Figure 4 It can be understood that, through the stamping process, a boss 3111 is punched out on the first end side 311 of the disk body 31, and accordingly, a recessed portion 3121 is formed at a position corresponding to the boss 3111 on the second end side 312. For the purpose of conveniently welding the negative electrode current collector 30 and the core-wound electrode group 20, in some embodiments, the second end side 312 has an annular welding area 3122 around the recessed portion 3121, and the surface of the welding area 3122 is suitable for abutting against the end face 21 of the core-wound electrode group 20. For example, the welding area 3122 is also configured to have a flat surface so that the surfaces of the two can fit closely to each other to improve the welding quality. In this case, during the welding of the negative electrode collector disc 30 and the core electrode group 20, the core electrode group 20 and the negative electrode collector disc 30 are first positioned by a jig. At this time, the annular welding area 3122 is the top surface of the second end side 312, thereby abutting against the end surface 21 of the core electrode group 20, that is, the surface of the welding area 3122 is in contact with the surface of the end surface 21 of the core electrode group 20, and then the welding area 3122 can be welded to the core electrode group 20 by laser penetration welding at the first end side 311, so that the negative electrode collector disc 30 and the core electrode group 20 form a combination.

[0056] refer to Figure 4In some embodiments, the diameter of the disk 31 is D1, and the diameter of the boss 3111 is d, satisfying d / D1=28% to 38%. As mentioned above, the diameter D1 of the disk 31 is substantially consistent with the diameter of the winding core electrode group 20. For example, taking the 21 series battery as an example, the diameter D1 of the disk 31 can be set to 19 to 21 mm; taking the 46 series battery as an example, the diameter D1 of the disk 31 can be set to 42 to 44 mm. In this way, continuing to take the 21 series cylindrical lithium battery as an example, the diameter of the boss 3111 is set to 5.32 to 7.98 mm. It can be understood that if the diameter of the boss 3111 is too large, its surface flatness will deteriorate, and its fit with the inner surface 121 of the bottom of the metal shell 10 will not be good, thereby affecting the welding quality; on the contrary, if the diameter of the boss 3111 is too small, the weldable area of ​​the boss 3111 is small, and it is easy to desolder during welding, which will increase the difficulty of subsequent welding process and increase the cost.

[0057] like Figure 5 As shown, in some embodiments, the thickness T of the disc body 31 is 0.1-0.5 mm. It is understandable that if the thickness T of the disc body 31 is too small, the mechanical strength of the disc body 31 is insufficient and it is easy to deform; on the contrary, if the thickness T of the disc body 31 is too large, the internal resistance of the battery will increase, and more longitudinal space will be occupied, thereby increasing the height of the battery. In addition, setting the thickness T of the disc body 31 to 0.1-0.5 mm can also effectively improve the processing technology, for example, it is easy to perform stamping to form the disc body 31 and the boss 3111.

[0058] Furthermore, if Figure 5 As shown, in some embodiments, the height difference between the surface of the boss 3111 and the surface of the first end side 311 is H, and satisfies: H / T = 18% to 30%. It can be understood that if the boss 3111 is set too high, that is, H / T is too large, then during the assembly process, the winding core electrode group 20 will squeeze and deform the periphery of the disk body 31, and will also occupy additional longitudinal space of the battery; on the contrary, if the boss 3111 is set too low, that is, H / T is too small, the boss 3111 is difficult to process, for example, the boss 3111 cannot be formed by a stamping process.

[0059] In order to ensure that the boss 3111 forms a good fit with the surface of the metal shell 10, in some embodiments, the flatness of the surface of the boss 3111 is 0.01-0.05 mm. It is understandable that if the flatness of the boss 3111 is too large, the fit between it and the shell bottom inner surface 121 of the bottom of the metal shell 10 is not good, thereby affecting the welding quality; on the contrary, if the flatness of the boss 3111 is too small, it is difficult to process and the cost is too high.

[0060] In some embodiments, the material of the disc body 31 is copper, and a nickel layer is plated on the surface of the disc body 31. Compared with the negative electrode current collector disc made of copper-nickel alloy, the copper material as the base material has the characteristic of extremely low internal resistance. At the same time, by plating the nickel layer on the surface of the disc body 31, the corrosion resistance of the negative electrode current collector disc 30 can be effectively improved.

[0061] Furthermore, the thickness of the nickel layer is set to 0.08-1.5 μm, more preferably 0.9-1.1 μm. It is understandable that if the nickel layer is too thin, it cannot play an anti-oxidation role; on the contrary, if the nickel layer is too thick, on the one hand, it increases the difficulty of the nickel plating process and the cost, and on the other hand, it increases the hardness of the disk, resulting in a decrease in the plasticity of the disk, and also increases the internal resistance, resulting in a decrease in battery performance.

[0062] An embodiment of the present application also provides a cylindrical lithium battery, which includes a metal shell 10, in which the negative electrode current collector 30 and the core electrode group 20 in the above embodiment are arranged, and the boss 3111 of the negative electrode current collector 30 is abutted and connected with the inner surface 121 of the shell bottom of the metal shell 10, and the second end side 312 of the negative electrode current collector 30 is connected to the core electrode group 20.

[0063] It can be understood that, due to the use of the negative electrode current collecting disk 30 of the above embodiment, the cylindrical lithium battery of this embodiment has higher performance and yield rate.

[0064] 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.

[0065] 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 negative electrode current collector plate, used for conductive connection between a metal shell (10) and a wound core electrode group (20), characterized in that: include: A disk body (31), the disk body (31) is circular, and the diameter of the disk body (31) is D1, and the diameter of the winding core pole group (20) is D2, satisfying: D1 / D2=90%-98%, the disk body (31) has a first end side (311) and a second end side (312) that are separated from each other, and the second end side (312) is used for connecting to the winding core pole group (20); The disc body (31) is provided with a boss (3111) with a flat surface at the first end side (311), the surface of the boss (3111) is higher than the surface of the first end side (311), and the surface area of ​​the boss (3111) is smaller than the surface area of ​​the first end side (311), and the surface of the boss (3111) is suitable for abutting against the inner surface (121) of the shell bottom of the metal shell (10).

2. The negative electrode current collector according to claim 1, characterized in that: The height difference between the surface of the boss (3111) and the surface of the first end side (311) is H, and the thickness of the disk body (31) is T, which satisfies: H / T=18% to 30%.

3. The negative electrode current collector according to claim 1, characterized in that: The boss (3111) is located in a central area of ​​the first end side (311).

4. The negative electrode current collector according to claim 1, characterized in that: The boss (3111) is circular, and the diameter of the boss (3111) is d, satisfying d / D1=28% to 38%.

5. The negative electrode current collecting disk according to any one of claims 1 to 4, characterized in that: The boss (3111) is formed by integral stamping of the disc body (31).

6. The negative electrode current collecting disk according to any one of claims 1 to 4, characterized in that: The second end side (312) forms a recessed portion (3121) at a position corresponding to the boss (3111), and a welding area (3122) is formed around the recessed portion (3121). The surface of the welding area (3122) is suitable for abutting against the end surface (21) of the winding core pole group (20).

7. The negative electrode current collecting disk according to any one of claims 1 to 4, characterized in that: The flatness of the surface of the boss (3111) is 0.01 to 0.05 mm.

8. The negative electrode current collecting disk according to any one of claims 1 to 4, characterized in that: The surface of the disk body (31) is plated with a nickel layer, and the thickness of the nickel layer is 0.08 to 1.5 μm.

9. The negative electrode current collecting disk according to claim 8, characterized in that: The material of the disk body (31) is copper.

10. A cylindrical lithium battery, characterized in that: The invention comprises a metal shell (10), wherein a core-wound electrode group (20) and a negative electrode collector disk (30) as claimed in any one of claims 1 to 9 are arranged in the metal shell (10), the boss (3111) of the negative electrode collector disk (30) is abutted and connected with the inner surface (121) of the shell bottom of the metal shell (10), and the second end side (312) of the negative electrode collector disk (30) is connected with the end surface (21) of the core-wound electrode group (20).

Images