Cylindrical lithium battery

Abstract

The utility model provides a cylindrical lithium battery. The cylindrical lithium battery comprises a shell, a negative electrode cover plate and a negative electrode current collecting disc, the shell comprises a first wall part, the negative electrode cover plate comprises a second wall part, the negative electrode current collecting disc comprises a third wall part, the shell, the negative electrode cover plate and the negative electrode current collecting disc are connected in a mutually nested mode, and the third wall part is arranged along the axial direction of the shell. According to the cylindrical lithium battery, the first wall part, the second wall part and the third wall part are overlapped at the set height, and the first wall part, the second wall part and the third wall part are integrally and hermetically connected through laser penetration welding, so that the process of welding the negative electrode current collecting disc and the shell does not need to be independently carried out, namely, the cylindrical lithium battery has the advantage of simple welding process, and the production efficiency is improved. The manufacturing cost can be effectively reduced, and the manufacturing efficiency is improved.

Description

Technical Field

[0001] The present application relates to the technical field of lithium-ion batteries, and in particular to 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 are also widely used in electric vehicles, energy storage and other fields.

[0003] In the related art, cylindrical lithium batteries often adopt a shell design with an open negative terminal, and after the core is put into the shell, the shell is sealed by welding the negative cover plate at the open end. However, since negative current collectors are currently added to the positive and negative electrodes of the core, before the above-mentioned sealing process, it is necessary to weld the negative current collector and the core electrode group, and the negative current collector and the shell in sequence. The process is relatively cumbersome, which seriously affects the manufacturing efficiency of cylindrical lithium batteries. Utility Model Content

[0004] The embodiment of the present application provides a cylindrical lithium battery to at least solve the technical problem of complicated shell sealing welding process of cylindrical lithium batteries existing in the related art.

[0005] A cylindrical lithium battery according to an embodiment of the present application includes:

[0006] A shell defines an inner cavity, the shell includes a first wall portion located at an end portion, the first wall portion surrounds and forms a first receiving interface communicating with the inner cavity;

[0007] A negative electrode cover plate, comprising a cover plate body and a second wall portion formed at the periphery of the cover plate body, wherein the negative electrode cover plate is nested in the first receiving interface and closes the first receiving interface by contacting and connecting the outer wall surface of the second wall portion with the inner wall surface of the first wall portion, and the second wall portion surrounds and forms a second receiving interface on a side facing the inner cavity;

[0008] A negative electrode current collector, the negative electrode current collector comprising a current collector body and a third wall portion formed at the periphery of the current collector body, the negative electrode current collector being nested in the second receiving interface by the outer wall surface of the third wall portion being in contact and connected with the inner wall surface of the second wall portion;

[0009] Wherein, along the axial direction of the shell, the first wall portion, the second wall portion and the third wall portion overlap at a set height, and the first wall portion, the second wall portion and the third wall portion are integrally and hermetically connected by laser through-welding.

[0010] The cylindrical lithium battery according to the embodiment of the present application has at least the following beneficial effects:

[0011] Since the shell, the negative electrode cover plate and the negative electrode current collector are connected in a nested manner, the first wall portion, the second wall portion and the third wall portion overlap at a set height along the axial direction of the shell, that is, the first wall portion, the second wall portion and the third wall portion form an overlapping area with a set height in the axial direction of the shell. As a result, the first wall portion, the second wall portion and the third wall portion can be sealed and connected as a whole by welding the overlapping area in a radial direction by a laser beam from the outside of the shell, so there is no need to perform a separate welding process for the negative electrode current collector and the shell. That is, the cylindrical lithium battery in the embodiment of the present application has the advantage of a simple welding process, which can effectively reduce manufacturing costs and improve manufacturing efficiency.

[0012] In a possible implementation manner, a height H of the overlap between the first wall portion, the second wall portion, and the third wall portion satisfies 2 mm ≤ H ≤ 5 mm.

[0013] In a possible implementation manner, the thickness of the second wall portion is smaller than the thickness of the first wall portion.

[0014] In a possible implementation manner, the thicknesses of the first wall portion, the second wall portion, and the third wall portion are configured to decrease in sequence.

[0015] In a possible implementation manner, the thickness of the first wall portion is smaller than the wall thickness of other portions of the housing.

[0016] In a possible implementation manner, the thickness of the first wall portion gradually decreases toward the end portion.

[0017] In a possible implementation manner, an outer wall surface of the first wall portion is provided with a chamfered portion.

[0018] In a possible implementation manner, an annular joint is formed between the shell and the negative electrode cover plate, and a sealing weld is provided at the joint.

[0019] In a possible implementation manner, the negative electrode cover plate is integrally stamped from a metal sheet.

[0020] In a possible implementation manner, the negative electrode current collecting plate is integrally stamped from a metal sheet.

[0021] In a possible implementation manner, the negative electrode cover plate and the first receiving interface are loosely fitted.

[0022] In a possible implementation manner, the negative electrode current collecting plate and the second receiving port are loosely connected. 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 is a cross-sectional schematic diagram of a cylindrical lithium battery provided in an embodiment of the present application;

[0025] Figure 2 yes Figure 1 A partial schematic diagram of the negative electrode side of a medium cylindrical lithium battery;

[0026] Figure 3 It is a cross-sectional schematic diagram of the negative terminal side of the shell of a cylindrical lithium battery provided in an embodiment of the application;

[0027] Figure 4 is a front view of a negative electrode cover plate in a cylindrical lithium battery provided in an embodiment of the present application;

[0028] Figure 5 yes Figure 4 A top view of the middle negative electrode cover;

[0029] Figure 6 is a front view of a negative electrode current collecting disk in a cylindrical lithium battery provided in an embodiment of the present application;

[0030] Figure 7 yes Figure 6 Bottom view of the middle negative electrode current collector;

[0031] Figure 8 yes Figure 6 Schematic diagram of the structure in which the middle negative electrode collector is connected to the core electrode group.

[0032] Reference numerals:

[0033] 10-shell, 101-inner cavity, 102-first wall portion, 103-first receiving interface, 104-negative terminal, 105-chamfered portion, 106-positive terminal;

[0034] 20-negative electrode cover plate, 201-cover plate body, 202-second wall portion, 203-second receiving interface, 204-explosion-proof groove, 205-first liquid injection hole;

[0035] 30-negative electrode current collecting plate, 301-current collecting plate body, 302-third wall portion, 303-second liquid injection hole;

[0036] 40- wound core electrode group, 401- negative electrode ear;

[0037] 50-Seams;

[0038] 60-combination. DETAILED DESCRIPTION

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] The following combination Figures 1 to 8 The cylindrical lithium battery of the embodiment of the present application is described in detail.

[0044] like Figure 1 , Figure 2 and Figure 3 As shown, the cylindrical lithium battery includes a shell 10, a negative electrode cover plate 20, a negative electrode current collector plate 30 and a core electrode group 40, wherein the shell 10, the negative electrode cover plate 20, the negative electrode current collector plate 30 and the core electrode group 40 are assembled to form the negative electrode of the cylindrical lithium battery.

[0045] The housing 10 defines an inner cavity 101 . The housing 10 includes a first wall portion 102 located at an end portion. The first wall portion 102 surrounds and forms a first receiving port 103 communicating with the inner cavity 101 .

[0046] The negative electrode cover plate 20 includes a cover plate body 201 and a second wall portion 202 formed on the periphery of the cover plate body 201. The negative electrode cover plate 20 is nested in the first receiving port 103 and closes the first receiving port 103 by connecting the outer wall surface of the second wall portion 202 to the inner wall surface of the first wall portion 102, and on the side facing the inner cavity 101, the second wall portion 202 surrounds to form the second receiving port 203.

[0047] The negative electrode current collecting disc 30 comprises a current collecting disc body 301 and a third wall portion 302 formed at the periphery of the current collecting disc body 301 . The negative electrode current collecting disc 30 is nested in the second receiving opening 203 by the outer wall surface of the third wall portion 302 being in contact with the inner wall surface of the second wall portion 202 .

[0048] In which, along the axial direction of the housing 10 , the first wall portion 102 , the second wall portion 202 and the third wall portion 302 overlap at a set height, and the first wall portion 102 , the second wall portion 202 and the third wall portion 302 are integrally sealed and connected by laser through-welding.

[0049] It can be understood that since the shell 10, the negative electrode cover plate 20 and the negative electrode collector plate 30 are connected in a nested manner, the first wall portion 102, the second wall portion 202 and the third wall portion 302 overlap at a set height along the axial direction of the shell 10, that is, the first wall portion 102, the second wall portion 202 and the third wall portion 302 form an overlapping area A with a set height in the axial direction of the shell 10, thereby, the first wall portion 102, the second wall portion 202 and the third wall portion 302 can be sealed and connected as a whole by the laser beam L1 from the outside of the shell 10 through-welding the overlapping area A in the radial direction, so that there is no need to perform a separate welding process for the negative electrode collector plate 30 and the shell 10, that is, the cylindrical lithium battery in the embodiment of the present application has the advantage of a simple welding process, which can effectively reduce the manufacturing cost and improve the manufacturing efficiency.

[0050] It can also be understood that in the embodiment of the present application, the overlapping area A is composed of the first wall portion 102 formed on the shell 10, the second wall portion 202 formed on the negative electrode cover plate 20, and the third wall portion 302 formed on the negative electrode collector plate 30 in the radial direction from the outside to the inside. Therefore, by laser through-welding the overlapping area A, a molten pool will be formed at the connection interface between the first wall portion 102 and the second wall portion 202, and the connection interface between the second wall portion 202 and the third wall portion 302. These molten pools will form a dense metal phase after cooling, so that the shell 10, the negative electrode cover plate 20 and the negative electrode collector plate 30 are sealed and connected, thereby achieving the sealing of the shell 10. Through the above structure, after helium detection, the maximum leakage rate of the shell 10 after sealing is not more than 9.9×10 -7 Pa·m 3 / s, the airtightness of the housing 10 meets the requirements.

[0051] In order to facilitate laser transmission and reduce the difficulty of the process, in some embodiments, the height of the overlap of the first wall portion 102, the second wall portion 202 and the third wall portion 302, that is, the height H of the overlapping area A satisfies 2mm≤H≤5mm. Within this high dimension range, the existing laser welding equipment and process can better achieve the penetration welding of the first wall portion 102, the second wall portion 202 and the third wall portion 302 along the radial direction from the laser beam L1 outside the shell 10, and will not affect the internal space of the shell 10.

[0052] In addition, in order to ensure that the welding energy can reach the third wall portion 302, so that the second wall portion 202 and the third wall portion 302 can be sealed and welded, in some embodiments, the thickness of the second wall portion 202 is set to be less than the thickness of the first wall portion 102. Further, the thicknesses of the first wall portion 102, the second wall portion 202 and the third wall portion 302 are set to decrease in sequence, thereby, laser penetration welding is adopted from the outside of the housing 10, and good welding between the first wall portion 102, the second wall portion 202 and the third wall portion 302 can also be ensured.

[0053] The housing 10 is described in detail below.

[0054] like Figure 1 , Figure 2 and Figure 3 As shown, it can be understood that for a cylindrical lithium battery, its shell 10 is cylindrical, and the outer diameter of the shell 10 determines the outer diameter and size series of the cylindrical lithium battery. For example, the cylindrical lithium battery of this embodiment can be a 46 series large cylindrical battery, that is, a cylindrical lithium battery with an outer diameter of 46 mm for the shell 10. It can also be understood that the shell 10 is made of metal material, for example, it can be stamped from nickel-plated steel, which has the advantages of high compressive strength, and at the same time, it is easy to weld and connect with the negative electrode cover plate 20 and the negative electrode collector plate 30, and it can also be used as the negative electrode of the cylindrical lithium battery.

[0055] It can be understood that the inner cavity 101 defined by the shell 10 is also cylindrical to accommodate the cylindrical core electrode group 40 formed by winding the positive electrode sheet, the negative electrode sheet and the separator. Figure 1 , Figure 2 and Figure 3The housing 10 has a positive terminal 106 and a negative terminal 104 that are separated from each other, wherein the positive terminal 106 corresponds to the positive electrode of the core electrode group 40, and the negative terminal 104 corresponds to the negative electrode of the core electrode group 40. On the side of the negative terminal 104, the housing 10 includes a first wall portion 102 located at the end, and the first wall portion 102 surrounds and forms a first receiving port 103 that communicates with the inner cavity 101. It can be understood that, on the one hand, the first receiving port 103 itself is open, so that the core electrode group 40 and the negative electrode collector 30 can enter the housing 10 through the opening of the first receiving port 103, and on the other hand, the first receiving port 103 is used to nest the negative electrode cover plate 20.

[0056] like Figure 1 , Figure 2 and Figure 3 As shown, in some embodiments, the first wall portion 102 is the portion of the housing 10 at the end of the negative terminal 104, that is, the first wall portion 102 is a toroidal body with a certain height and thickness, and thus, the first wall portion 102 has an annular inner wall surface on the side located at the inner cavity 101, that is, the contour shape of the first receiving port 103 is cylindrical. It can be understood that a part of the housing 10 itself is used as the first wall portion 102, and thus, the first wall portion 102 can be directly obtained in the stamping process of the housing 10, avoiding complicated processes, and the negative electrode cover plate 20 can also be nested in the first receiving port 103 through a simple assembly movement, such as an insertion movement along the axial direction of the housing 10, which is very convenient.

[0057] In addition, since the shell 10 is cylindrical, it can be understood that the opening shape of the first receiving port 103 is circular and has a flat cross-section. Therefore, the diameter of the first receiving port 103 is equal to the inner diameter of the shell 10. Therefore, the outer diameter of the core pole group 40 can be designed to be close to the inner diameter of the shell 10 to effectively increase the utilization rate of the inner cavity 101.

[0058] It is understandable that in this embodiment, the laser light source on the outside of the shell 10 is used to achieve the sealed welding of the shell 10 by laser penetration welding. Therefore, if the thickness of the first wall portion 102 is too large, the energy of the laser penetration welding will be excessively weakened, affecting the welding effect. In order to have sufficient compressive strength, the shell 10 usually has a certain thickness. Therefore, in order to improve the quality and effect of welding, in some embodiments, the thickness of the first wall portion 102 is set to be less than the wall thickness of the rest of the shell 10. The actual thickness of the first wall portion 102 can be determined according to parameters such as welding power.

[0059] It is understandable that the thickness of the first wall portion 102 can be reduced by removing the surface material of the first wall portion 102. For example, a stepped hole is provided on the inner wall surface of the first wall portion 102, that is, the inner diameter of the first receiving port 103 is enlarged, which can also achieve the purpose of reducing the thickness of the first wall portion 102.

[0060] like Figure 1 , Figure 2 and Figure 3 As shown, in some embodiments, by chamfering the outer wall surface of the first wall portion 102, that is, providing a chamfered portion 105 there, the thickness of the first wall portion 102 gradually decreases toward the end of the first wall portion 102, so that the thickness of the first wall portion 102 is less than the wall thickness of the remaining parts of the housing 10. The chamfered portion 105 is easy to process and easy to implement. Of course, it is not limited to this, and the thickness of the first wall portion 102 can also be reduced in thickness.

[0061] The negative electrode cover plate 20 is described in detail below.

[0062] like Figure 4 and Figure 5 As shown, in some embodiments, the negative electrode cover plate 20 includes a cover plate body 201 and a second wall portion 202 formed at the periphery of the cover plate body 201. Specifically, since the opening shape of the first receiving port 103 of the shell 10 is circular, the negative electrode cover plate 20 is also circular as a whole, so as to close the first receiving port 103 after assembly, and the second wall portion 202 located at the periphery is an annular wall, and the second wall portion 202 has an annular outer wall surface that can be matched with the inner wall surface of the aforementioned first wall portion 102, thereby, in the process of pushing the negative electrode cover plate 20 to perform assembly movement along the direction of entering the inner cavity 101, the first wall portion 102 and the second wall portion 202 can fit well and can slide relative to each other, so as to achieve nesting between the two and form an overlapping area A with a set height, so as to facilitate through-welding connection to achieve sealing of the shell 10.

[0063] Further, in order to facilitate the smooth nesting of the first wall portion 102 and the second wall portion 202, in the present embodiment, the negative electrode cover plate 20 and the first receiving port 103 are loosely connected. Specifically, when the negative electrode cover plate 20 is nested in the first receiving port 103, there is a certain gap between the inner wall surface of the first wall portion 102 and the outer wall surface of the second wall portion 202. It should be noted that the loose fit described herein refers to a gap fit between the two components.

[0064] like Figure 1 and Figure 2As shown, it can be understood that after the first receiving port 103 is sealed by the negative electrode cover plate 20, in order to make the bottom of the negative terminal 104 of the cylindrical lithium battery flat, in some embodiments, the second wall portion 202 is set to bulge upward along the edge of the cover plate body 201, so that after the negative electrode cover plate 20 is pushed to move in the direction of entering the inner cavity 101 for assembly and accurate positioning, the bottom of the cover plate body 201 is flush with the end face of the first wall portion 102, and a ring-shaped seam 50 is formed between the two. Further, secondary welding can be performed at the seam 50, for example, the seam 50 is welded by the laser beam L2 at the bottom of the shell, and the sealing weld formed at the seam 50 can further enhance the sealing effect of the shell 10. It can be understood that, since in this embodiment, the negative electrode collector 30 is sealed inside the shell 10, the bottom of the cylindrical lithium battery has only one seam 50 between the shell 10 and the negative electrode cover plate 20, which can achieve a better sealing effect.

[0065] It can also be understood that the second wall portion 202 protrudes upward along the edge of the cover body 201, thereby defining a second receiving port 203 for nesting the negative electrode current collecting disc 30 around the circumferential direction of the cover body 201. It can be understood that, on the one hand, the second receiving port 203 itself is open, thereby, the negative electrode current collecting disc 30 can be embedded into the negative electrode cover 20 through the second receiving port 203. Figure 2 and Figure 3 As shown, in some embodiments, the second wall portion 202 is a toroidal body with a certain height and thickness, so that the second wall portion 202 has an annular inner wall surface on the inner circumference, that is, the contour shape of the second receiving port 203 is cylindrical. It can be understood that the negative electrode current collecting plate 30 can also be nested in the second receiving port 203 through a simple assembly movement, which is very convenient.

[0066] In some embodiments, for the purpose of facilitating processing, the negative electrode cover plate 20 can be integrally stamped from a metal sheet to form a cover plate body 201 and a second wall portion 202 protruding upward along an edge of the cover plate body 201 .

[0067] As shown in the figure, in some embodiments, the negative electrode cover plate 20 is further provided with an explosion-proof notch 204, so that when the cylindrical lithium battery is used due to internal pressure imbalance, the explosion-proof notch 204 can be broken and flipped to achieve rapid pressure relief inside the battery, which can improve the safety of the battery. Since the explosion-proof notch 204 is provided on the negative electrode cover plate 20, the gas inside the battery can be directional released from the bottom of the battery.

[0068] In addition, if Figure 4 and Figure 5 As shown, the negative electrode cover plate 20 is further provided with a first liquid injection hole 205, thereby facilitating the liquid injection process after the shell 10 passes the sealing test.

[0069] The negative electrode current collecting disk 30 is described in detail below.

[0070] like Figure 6 and Figure 7 As shown, in some embodiments, the negative electrode current collector 30 includes a current collector body 301 and a third wall portion 302 formed on the periphery of the current collector body 301. Specifically, since the opening shape of the second receiving port 203 formed on the negative electrode cover plate 20 is circular, the negative electrode current collector 30 is also circular as a whole, and the third wall portion 302 located on the periphery of the current collector body 301 is an annular wall, and the third wall portion 302 has an annular outer wall surface that can be matched with the inner wall surface of the aforementioned second wall portion 202, thereby, in the process of pushing the negative electrode cover plate 20 to move in the direction of entering the inner cavity 101 for assembly (at this time, the negative electrode current collector 30 has entered the inner cavity 101 of the shell 10 with the winding core electrode group 40), the second wall portion 202 and the third wall portion 302 can fit well and can slide relative to each other, so as to achieve nesting between the two and form an overlapping area A with a set height, so as to facilitate through-welding connection to achieve sealing of the shell 10.

[0071] It can be understood that the third wall portion 302 protrudes downward along the edge of the collector plate body 301, so that the third wall portion 302 has a certain height in the axial direction, thereby ensuring the height of the overlapping area A, and the negative electrode collector plate 30 is light. Of course, it is not limited to this. For example, the collector plate body 301 can also be set as a disc-shaped member with a suitable thickness, and the outer wall of the body can be directly used as the third wall portion 302 without setting a downward protrusion.

[0072] Furthermore, in order to facilitate the smooth nesting of the second wall portion 202 and the third wall portion 302, in this embodiment, the negative electrode current collecting disc 30 is loosely connected to the second receiving port 203. Specifically, when the negative electrode current collecting disc 30 is nested in the second receiving port 203, there is a certain gap between the inner wall surface of the second wall portion 202 and the outer wall surface of the third wall portion 302.

[0073] like Figure 6 and Figure 7 As shown, it can be understood that in some embodiments, the third wall portion 302 is configured to protrude downward along the edge of the collector plate body 301. In other words, the collector plate body 301 has a flat surface on the side facing the core electrode group 40, that is, on the side away from the negative electrode cover plate 20, so as to facilitate welding connection with the negative electrode of the core electrode group 40.

[0074] In some embodiments, for the purpose of facilitating processing, the negative electrode current collecting disc 30 can be integrally stamped from a metal sheet to form a current collecting disc body 301 and a third wall portion 302 protruding downward along an edge of the current collecting disc body 301 .

[0075] In addition, if Figure 6 and Figure 7 As shown, the negative electrode current collecting plate 30 is further provided with a second liquid injection hole 303, the position of which corresponds to the position of the first liquid injection hole 205 formed on the negative electrode cover plate 20, thereby facilitating the liquid injection process after the shell 10 passes the sealing test.

[0076] It is understandable that during the assembly of the cylindrical lithium battery, the negative electrode collector plate 30 must first be welded to the core electrode group 40. Specifically, during assembly, the core electrode group 40 and the negative electrode collector plate 30 are positioned using a jig so that the top surface of the negative electrode collector plate 30 is in good contact with the negative electrode (the flattened negative electrode tab 401) of the core electrode group 40, and are connected by, for example, laser welding to form a Figure 8 The assembly 60 shown. In the subsequent process, after the assembly 60 is installed into the housing 10 through the first receiving port 103, the first receiving port 103 can be sealed by the negative electrode cover plate 20. Through the above-mentioned assembly sequence and actions, the first wall portion 102, the second wall portion 202 and the third wall portion 302 are mutually nested and overlapped in the radial direction within the set height range, so that the first wall portion 102, the second wall portion 202 and the third wall portion 302 are integrally sealed and connected by the laser penetration welding process, that is, the housing 10, the negative electrode cover plate 20 and the negative electrode collector 30 are sealed and connected, so as to achieve the sealing of the housing 10.

[0077] 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.

[0078] 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 cylindrical lithium battery, characterized in that: include: A shell defines an inner cavity, the shell includes a first wall portion located at an end portion, the first wall portion surrounds and forms a first receiving interface communicating with the inner cavity; A negative electrode cover plate, comprising a cover plate body and a second wall portion formed at the periphery of the cover plate body, wherein the negative electrode cover plate is nested in the first receiving interface and closes the first receiving interface by contacting and connecting the outer wall surface of the second wall portion with the inner wall surface of the first wall portion, and the second wall portion surrounds and forms a second receiving interface on a side facing the inner cavity; A negative electrode current collector, the negative electrode current collector comprising a current collector body and a third wall portion formed at the periphery of the current collector body, the negative electrode current collector being nested in the second receiving interface by the outer wall surface of the third wall portion being in contact and connected with the inner wall surface of the second wall portion; Wherein, along the axial direction of the shell, the first wall portion, the second wall portion and the third wall portion overlap at a set height, and the first wall portion, the second wall portion and the third wall portion are integrally and hermetically connected by laser through-welding.

2. The cylindrical lithium battery according to claim 1, characterized in that: A height H of the first wall portion, the second wall portion, and the third wall portion overlapping each other satisfies 2 mm ≤ H ≤ 5 mm.

3. The cylindrical lithium battery according to claim 1, characterized in that: The thickness of the second wall portion is smaller than the thickness of the first wall portion.

4. The cylindrical lithium battery according to claim 3, characterized in that: The thicknesses of the first wall portion, the second wall portion, and the third wall portion are arranged to decrease in sequence.

5. The cylindrical lithium battery according to claim 3, characterized in that: The thickness of the first wall portion is smaller than the wall thickness of other parts of the housing.

6. The cylindrical lithium battery according to claim 5, characterized in that: The thickness of the first wall portion gradually decreases toward the end portion.

7. The cylindrical lithium battery according to claim 5, characterized in that: The outer wall surface of the first wall portion is provided with a chamfered portion.

8. The cylindrical lithium battery according to any one of claims 1 to 7, characterized in that: An annular joint is formed between the first wall portion and the negative electrode cover plate, and a sealing weld is provided at the joint.

9. The cylindrical lithium battery according to any one of claims 1 to 7, characterized in that: The negative electrode cover is integrally formed by stamping a metal sheet; and / or The negative electrode current collecting plate is integrally formed by stamping a metal sheet.

10. The cylindrical lithium battery according to any one of claims 1 to 7, characterized in that: The negative electrode cover plate and the first receiving interface are loosely connected; and / or The negative electrode current collecting plate and the second receiving port are loosely connected.

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