BATTERY COVER PLATE ASSEMBLY, BATTERY CELL, BATTERY, AND POWER CONSUMING DEVICE

Provided are a battery cover plate assembly, including: a cover plate provided with a filling port; and a sealing pin for sealing the filling port; wherein the sealing pin includes a main body portion and a welding portion, and the welding portion is located at a periphery of the main body portion and extends from the main body portion toward an outer circumferential side; and the cover plate is provided with a second recess and a first recess, which are sequentially arranged from the inside to the outside at a periphery of the filling port, the main body portion is located in the second recess, and the welding portion is welded to a bottom surface of the first recess. According to the present application, the main body portion is located in the second recess, and the welding portion is welded to the bottom surface of the first recess.

TECHNICAL FIELD

The present application relates to the field of batteries, and in particular to a battery cover plate assembly, a battery cell, a battery and a power consuming device.

BACKGROUND ART

In the existing battery manufacturing process, after a battery cell is filled with electrolyte, a filling port needs to be sealed with a sealing pin. However, there is a problem of electrolyte leakage of the battery cell during actual use. Therefore, the electrolyte leakage of battery cells has become an urgent problem to be solved.

SUMMARY OF THE INVENTION

Technical Problem

In view of the above problem, the present application proposes a battery cover plate assembly, in order to solve the above technical problem of electrolyte leakage of a battery cell.

Technical Solutions

To achieve the above objective, the present application provides a battery cover plate assembly, including: a cover plate provided with a filling port; and a sealing pin for sealing the filling port; wherein the sealing pin includes a main body portion and a welding portion, and the welding portion is located at a periphery of the main body portion and extends from the main body portion toward an outer circumferential side; and the cover plate is provided with a second recess and a first recess, which are sequentially arranged from the inside to the outside at a periphery of the filling port, the main body portion is located in the second recess, and the welding portion is welded to a bottom surface of the first recess.

Further, the diameter of the bottom surface of the first recess is greater than the diameter of the sealing pin.

In the above technical solution, the diameter of the bottom surface of the first recess is greater than the diameter of the sealing pin, which facilitates the welding of the welding portion to the bottom surface of the first recess, so as to prevent the affection on the welding quality due to the welding seam falling on the edge of the first recess.

Further, the depth of the first recess is greater than the thickness of the welding portion.

In the above technical solution, the main body portion is accommodated in the second recess, and the depth of the first recess is greater than the thickness of the welding portion, so that the top of the sealing pin is lower than an upper surface of the cover plate, reducing the affection on the sealing performance of the sealing pin by impact.

Further, a buffer portion is provided between the main body portion and the welding portion, and the buffer portion is arched in a thickness direction of the main body portion.

In the above technical solution, the buffer portion can absorb the stress generated during welding of the welding portion, so as to avoid the sealing failure of the sealing pin due to the welding stress.

Further, the buffer portion is arched from the main body portion toward the second recess.

In the above technical solution, the buffer portion is arched from the main body portion toward the second recess, so that the buffer portion is located in the second recess, which achieves a limiting effect when the sealing pin is aligned with the second recess so as to facilitate the alignment of the sealing pin during mounting, and the buffer portion being located in the second recess can avoid the deformation of the buffer portion by impact or the sealing failure of the sealing pin.

Further, a side wall of the second recess is an inclined surface, and the buffer portion has gaps from the inclined surface and a bottom surface of the second recess.

In the above technical solution, the side wall of the second recess is an inclined surface, which can avoid interference with the buffer portion; and the buffer portion has gaps from the inclined surface and the bottom surface of the second recess, which can ensure that the welding portion is in effective contact with the bottom surface of the first recess, and is also conducive to discharge of the vapor generated by the electrolyte during welding to the outside via the gaps, thereby ensuring the welding sealing performance of the sealing pin.

Further, one or more welding seams are welded between the welding portion and the bottom surface of the first recess.

In the above technical solution, more than one welding seam is welded between the welding portion and the welding surface, which can improve the welding sealing performance between the sealing pin and the filling port.

Further, the bottom surface of the first recess is a flat surface; orthe bottom surface of the first recess is an inclined surface, the inclined surface is inclined from high to low toward the filling port, and the bottom surface of the welding portion is attached to the inclined surface.

Further, an angle of the bottom surface of the first recess with respect to the horizontal plane is 0° to 10°.

In order to solve the above technical problem, the present application further provides another technical solution:a battery cell, including: a shell; an electrode assembly arranged in the shell; and a cover plate assembly, which is the battery cover plate assembly as described in any one of the above technical solutions and is connected to the shell in a sealing manner.

The present application further provides another technical solution:a battery, including: the battery cell as described in the above technical solution; and a case configured to accommodate the battery cell.

The present application further provides another technical solution:a power consuming device, including the battery as described in the above technical solution for supplying electric energy.

Compared with the prior art, in the above technical solutions, a second recess and a first recess are sequentially arranged from the inside to the outside at the periphery of the filling port, the main body portion is located in the second recess, and the welding portion is welded to the bottom surface of the first recess. The second recess is configured to receive the electrolyte, so as to reduce the residual electrolyte on the bottom surface of the first recess, and the bottom surface of the first recess is welded to the welding portion of the sealing pin, so as to prevent the sealing pin from being welded to the side wall of the filling port, thereby improving the welding sealing performance between the sealing pin and the filling port.

The above description is only an overview of the technical solutions of the present application. In order to more clearly understand the technical means of the present application to implement same according to the contents of the description, and in order to make the above and other objectives, features and advantages of the present application more obvious and understandable, specific implementations of the present application are exemplarily described below.

Beneficial Effects

In the above technical solutions, a second recess and a first recess are sequentially arranged from the inside to the outside at the periphery of the filling port, the main body portion is located in the second recess, and the welding portion is welded to the bottom surface of the first recess. The second recess is configured to receive the electrolyte, so as to reduce the residual electrolyte on the bottom surface of the first recess, and the bottom surface of the first recess is welded to the welding portion of the sealing pin, so as to prevent the sealing pin from being welded to the side wall of the filling port, thereby improving the welding sealing performance between the sealing pin and the filling port.

The reference signs in the Detailed Description of Embodiments are as follows:1Vehicle,10Battery,11Controller,12Motor;20Battery module,21Battery cell,211Cover plate,211aElectrode terminal,212Shell,213Cell assembly,214Sealing pin;2141Main body portion,2142Welding portion,2143Buffer portion,2144Welding seam;2111Filling port,2112First recess,2113Second recess;A Angle of bottom surface of first recess with respect to horizontal plane;30Case,301First portion,302Second portion.

DETAILED DESCRIPTION OF EMBODIMENTS

Embodiments of the technical solutions of the present application will be described in detail below with reference to the accompanying drawings. The following embodiments are merely intended to more clearly illustrate the technical solutions of the present application, so they merely serve as examples, but are not intended to limit the scope of protection of the present application.

It should be noted that, unless otherwise specified, the technical terms or scientific terms used in the embodiments of the present application shall have ordinary meanings understood by persons skilled in the art to which the embodiments of the present application belong.

In the description of the embodiments of the present application, the orientation or position relationship indicated by the technical terms “central”, “longitudinal”, “transverse”, “length”, “width”, “thickness”, “upper”, “lower”, “front”; “rear”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inner”, “outer”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential” and so on are based on the orientation or position relationship shown in the accompanying drawings and are merely intended to facilitate and simplify the description of the embodiments of the present application, rather than indicating or implying that the apparatus or element considered must have a particular orientation or be constructed and operated in a particular orientation, and therefore not to be construed as limiting the embodiments of the present application.

In addition, the technical terms “first”, “second” and so on are used for descriptive purposes only, and cannot be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. In the description of the embodiments of the present application, the phrase “a plurality of” means two or more, unless otherwise explicitly and specifically defined.

In the description of the embodiments of the present application, unless otherwise explicitly specified and defined, the technical terms such as “mounting”, “connecting”, “connection”, “fixing”, etc. should be understood in a broad sense, for example, they may be a fixed connection, a detachable connection, or an integrated connection; may be a mechanical connection or an electric connection; and may be a direct connection or an indirect connection by means of an intermediate medium, or may be internal communication between two elements or interaction between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to specific situations.

In the description of the embodiments of the present application, unless otherwise explicitly specified and defined, a first feature being “above” or “below” a second feature may be direct contact between the first feature and the second feature, or indirect contact between the first feature and the second feature by means of an intermediate medium. Moreover, the first feature being “on”, “above”, and “over” the second feature may be the first feature being directly above or obliquely above the second feature, or simply mean that the first feature is at a higher level than the second feature. The first feature being “under”, “below” and “underneath” the second feature may be the first feature being right below or obliquely below the second feature, or only means that the level height of the first feature being less than that of the second feature.

After the secondary filling of the lithium-ion battery, in order to ensure the negative pressure environment in the shell to prevent external gas and moisture from entering the cell, the filling port needs to be sealed. In the existing sealing process, initial sealing is performed with a sealing pin, then the residual electrolyte in and around the filling port is removed by means of manual cleaning and laser cleaning, and finally, the sealing pin is mounted, and laser welding is performed. However, it is difficult to thoroughly remove the residual electrolyte at the periphery of the filling port during filling, which will lead to defects such as welding burst points and pores.

The present application provides a battery case, a battery including such a case, and a power consuming device using the battery. Such a case is suitable for any batteries, such as battery modules and battery packs, or primary batteries and secondary batteries. For example, the secondary batteries include Ni-MH batteries, Ni-Cd batteries, lead acid batteries (or lead accumulators), lithium-ion batteries, sodium-ion batteries, polymer batteries, and the like. Such a battery is suitable for various power consuming devices using a battery, such as mobile phones, portable apparatuses, laptops, battery cars, electric toys, electric tools, electric vehicles, ships and spacecraft. For example, the spacecrafts include airplanes, rockets, space shuttles, space vehicles, etc.; and the battery is configured to provide electric energy for the power consuming device described above.

It should be understood that the technical solutions described in the embodiments of the present application are not only applicable to the battery and the power consuming device described above, but also applicable to all batteries each including a case and power consuming devices using batteries. However, for the brevity of description, in the following embodiments, the electric vehicle is used as an example for description.

Referring toFIG.1,FIG.1is a schematic structural diagram of a vehicle1according to some embodiments of the present application. The vehicle1may be a fuel vehicle, a gas vehicle, or a new energy vehicle. The new energy vehicle may be a battery electric vehicle, a hybrid electric vehicle, or an extended-range vehicle, etc. A battery10is provided inside the vehicle1, and the battery10may be arranged at the bottom, the front or the back of the vehicle1. The battery10may be configured to supply power to the vehicle1. For example, the battery10may serve as a power supply for operating the vehicle1. The vehicle1may further include a controller11and a motor12. The controller11is configured to control the battery10to supply power to the motor12, for example, to meet working power requirements during starting, navigation and traveling of the vehicle1.

In some embodiments of the present application, the battery10can not only serve as a power supply for operating the vehicle1, but also serve as a power supply for driving the vehicle1, instead of or partially instead of fuel or natural gas, to provide driving power for the vehicle1.

In order to satisfy different electricity requirements, the battery10may include a plurality of battery cells21. The battery cell21refers to the minimum unit of a battery module or a battery pack. The plurality of battery cells21may be connected in series and/or in parallel via electrode terminals (corresponding to electrode terminals211ainFIG.4, and not shown inFIG.1) for use in various application scenarios. The battery mentioned in the present application includes a battery module or a battery pack. The plurality of battery cells21may be connected in series or in parallel or in series-parallel. The series-parallel connection refers to a combination of serial connection and parallel connection. The battery10may also be referred to as a battery pack. In the embodiments of the present application, the plurality of battery cells21may directly form a battery pack, or may first form battery modules20, and then the battery modules20may form a battery pack.

FIG.2shows a schematic structural diagram of a battery10according to an embodiment of the present application. InFIG.2, the battery10may include a plurality of battery modules20and a case30, the plurality of battery modules20being accommodated in the case30. The case30is configured to accommodate the battery cells21or the battery modules20, so as to prevent a liquid or other foreign objects from affecting charging or discharging of the battery cells21. The case30may be of a simple three-dimensional structure such as an individual cuboid, cylinder or sphere, or of a complex three-dimensional structure composed of simple three-dimensional structures such as a cuboid, a cylinder or a sphere, which will not limited in the embodiments of the present application. The case30may be made of alloy such as aluminium alloy and iron alloy, or a polymer material such as polycarbonate and polyisocyanurate foam plastics, or a composite material such as glass fibers plus epoxy resin, which will not limited in the embodiments of the present application.

In some embodiments, the case30may include a first portion301and a second portion302. The first portion301and the second portion302are fitted together in a covering manner, and the first portion301and the second portion302jointly define a space for accommodating the battery cells21. The second portion302may be of a hollow structure with one end open, the first portion301may be of a plate-like structure, and the first portion301covers an open side of the second portion302, so that the first portion301and the second portion302jointly define the space for accommodating the battery cells21. The first portion301and the second portion302may also each be of a hollow structure with one side open, and the open side of the first portion301covers the open side of the second portion302.

FIG.3shows a schematic structural diagram of a battery module20according to an embodiment of the present application. InFIG.3, the battery module20may include a plurality of battery cells21. The plurality of battery cells21may be first connected in series or in parallel or in series-parallel to form a battery module20, and the plurality of battery modules20may be then connected in series or in parallel or in series-parallel to form a battery10. In the present application, the battery cell21may include a lithium-ion battery cell, a sodium-ion battery cell, a magnesium-ion battery cell, etc., which will not limited in the embodiments of the present application. The battery cell21may be cylindrical, flat, cuboid or in another shape, which will not limited in the embodiments of the present application. The battery cells21generally include three types depending on the way of package: cylindrical battery cells21, prismatic battery cells21and pouch battery cells21, which will also not be limited in the embodiments of the present application. However, for the sake of brevity, the following embodiments will be described by taking the prismatic battery cells21as an example.

FIG.4is a schematic structural exploded view of a battery cell21according to some embodiments of the present application. The battery cell21refers to the minimum unit of the battery10. As shown inFIG.4, the battery cell21includes a cover plate211, a shell212, and a cell assembly213.

The cover plate211refers to a component that covers an opening of the shell212to isolate an internal environment of the battery cell21from an external environment. Without limitation, the cover plate211may have a shape adapted to that of the shell212to fit with the shell212. Optionally, the cover plate211may be made of a material (such as aluminium alloy) with certain hardness and strength, and thus the cover plate211is less prone to deformation when subjected to compression or collision, so that the battery cell21can have a higher structural strength, and the safety performance can also be improved. The cover plate211may be provided with functional components such as electrode terminals211a.The electrode terminals211amay be configured to be electrically connected to the cell assembly213for output or input of electric energy for the battery cell21. In some embodiments, cover plate cover211may be further provided with a pressure relief mechanism configured for relieving internal pressure when the pressure or temperature inside the battery cell21reaches a threshold. The cover plate211may also be made of various materials, such as copper, iron, aluminium, stainless steel, an aluminium alloy, plastic, etc., which will not be particularly limited in the embodiments of the present application. In some embodiments, an insulating member may be further provided on an inner side of the cover plate211. The insulating member may be configured to isolate electrical connection components within the shell212from the cover plate211, so as to reduce the risk of short circuit. As an example, the insulating member may be made of plastic, rubber, etc.

The shell212is an assembly for fitting with the cover plate211to form the internal environment of the battery cell21, wherein the formed internal environment may be used for accommodating the cell assembly213, an electrolyte solution (not shown) and other components. The shell212and the cover plate211may be separate components, and the shell212may be provided with an opening, at which the cover plate211covers the opening to form the internal environment of the battery cell21. Without limitation, the cover plate211and the shell212may also be integrated. Specifically, the cover plate211and the shell212can firstly form a common connection surface before other components are placed into the shell, and then the cover plate211covers the shell212when the interior of the shell212needs to be packaged. The shell212may have various shapes and various sizes, for example, in the form of a cuboid, a cylinder, a hexagonal prism, etc. Specifically, the shape of the shell212may be determined according to the specific shape and dimensions of the cell assembly213. The shell212may be made of various materials, such as copper, iron, aluminium, stainless steel, an aluminium alloy, plastic, which will not particularly limited in the embodiments of the present application.

The cell assembly213is a component in the battery cell21where an electrochemical reaction takes place. The shell212may contain one or more cell assemblies213. The cell assembly213is mainly formed by winding or stacking a positive electrode plate and a negative electrode plate, and a separator is usually provided between the positive electrode plate and the negative electrode plate. Parts of the positive electrode plate and the negative electrode plate that contain active substances form a body portion of the cell assembly, and parts of the positive electrode plate and the negative electrode plate that do not contain active substances each form a tab (not shown). A positive electrode tab and a negative electrode tab may be both located at one end of the body portion or respectively at two ends of the body portion. In charge and discharge processes of a battery10, the positive active substance and the negative active substance react with the electrolyte, and the tabs are connected to the electrode terminals211asuch that a current loop is formed.

Referring toFIGS.5and6, the present application provides a battery cover plate assembly, including a cover plate211and a sealing pin214. The cover plate211is provided with a filling port2111.

The sealing pin214is configured to seal the filling port2111, and the sealing pin214includes a main body portion2141and a welding portion2142. The welding portion2142is located at a periphery of the main body portion2141, and protrudes from the main body portion2141toward an outer circumferential side. The cover plate211is provided with a second recess2113and a first recess2112, which are arranged from the inside to the outside at the periphery of the filling port2111, the main body portion2141is located in the first recess2112, and the welding portion2142is welded to a bottom surface of the first recess2112.

The filling port2111penetrates the upper surface and the lower surface of the cover plate211. The filling port2111may be a cylindrical hole, a tapered hole, or other structures.

The sealing pin214is configured to seal the filling port2111to prevent the electrolyte in the battery10from leaking from the filling port2111. The main body portion2141and the welding portion2142of the sealing pin214may be integrally formed. In order to ensure the sealing effect of the sealing pin214during sealing, the sealing pin214is made of a weldable material. Optionally, the sealing pin214may be made of stainless steel or aluminium alloy. When the sealing pin214is pressed, the sealing pin214will deform to a certain extent. Therefore, the sealing pin214may also be made of an elastic material, can return to the original state after deformed, and is less prone to damage when being pressed. The sealing pin214may be made of plastic or rubber.

The height of the bottom surface of the first recess2112is greater than that of the bottom surface of the second recess2113. The cross-sections of the first recess2112and the second recess2113may be circular, square or in other shapes. Optionally, the cross-sections of the first recess2112and the second recess2113are circular and have no dead corner, which facilitates removal of the residual electrolyte on the bottom surfaces of the recesses.

The second recess2113may be configured to accommodate the electrolyte, so as to reduce the residual electrolyte on the bottom surface of the first recess2112. The bottom surface of the first recess2112is welded to the welding portion2142of the sealing pin214, which prevents the sealing pin214from welding to the side wall of the filling port2111, thereby improving the welding sealing performance between the sealing pin214and the filling port2111.

In an optional embodiment, the diameter of the bottom surface of the first recess2112is greater than the diameter of the sealing pin214.

As shown inFIG.6, the first recess2112and the second recess2113have the filling port2111as the center of the circle, the diameter of the bottom surface of the first recess2112is the distance between two end points of the first recess2112in the radial direction of the filling port2111(i.e., the outer diameter of the first recess2112). The larger the diameter of the bottom surface of the first recess2112is, the larger the weldable area, which facilitates the welding of the welding portion2142to the bottom surface of the first recess2112, so as to avoid the affection on the welding quality due to the welding seam2144falling on the edge of the first recess2112. The distance between the welding point, where the bottom surface of the first recess2112is welded to the welding portion2142, and the side wall of the first recess2112should be set within a reasonable range, so that the heat during welding is not easily transferred to the region of the second recess2113where electrolyte is likely to leave residue, so as to prevent the electrolyte in the second recess2113from being heated to generate gas.

In an optional embodiment, the depth of the first recess2112is greater than the thickness of the welding portion2142.

The depth of the first recess2112refers to the difference between the height of the bottom surface of the first recess2112and the height of the upper surface of the cover plate211. During assembly, the bottom surface of the welding portion2142of the sealing pin214comes into contact with the bottom surface of the first recess2112, and the height of the top of the welding portion2142is the height of the bottom surface of the first recess2112plus the thickness of the welding portion2142. If the top of the welding portion2142is higher than the upper surface of the cover plate211, the welding portion2142is more “protruding” relative to the upper surface of the cover plate211and is more likely to be impacted, so as to cause the sealing pi'214to become loose and crack, thus affecting the sealing effect of the sealing pin214. If the depth of the first recess2112is greater than the thickness of the welding portion2142, the upper surface of the cover plate211is higher than the top of the welding portion2142, and the upper surface of the cover plate211will receive the main impact force. In this way, the affection on the sealing pin214when being impacted is greatly reduced, thereby reducing the affection on the sealing performance.

In an optional embodiment, a buffer portion2143is provided between the main body portion2141and the welding portion2142, and the buffer portion2143is arched in the thickness direction of the main body portion2141.

The shape of the buffer portion2143is not limited and may be upwardly arched or downwardly arched. A lot of heat will be generated during the welding process of the sealing pin214, so that the sealing pin214is heated to expand; and when the temperature of the sealing pin drops, the sealing pin214will shrink, so that the sealing pin214and the welding seam2144will generate great internal stress. The arched structure of the buffer portion2143can effectively absorb the stress that changes as the temperature changes during the welding process of the welding portion2142, so as to prevent the sealing pin214and the welding seam2144from being broken due to excessive stress. The internal stress generated in the weldment during welding and the welding thermal process will cause changes in the shape and size of the weldment. At this time, the heat at the welding seam2144is quickly transferred to the sealing pin214via the welding portion2142, and the sealing pin214is heated to expand the deform to a certain extent. After the welding is completed, the sealing pin214gradually cools down and begins to shrink, which easily causes rupture at the welding portion2142. In order to eliminate and reduce the welding residual stress, the buffer portion2143is provided at the sealing pin214, and the welding residual stress is absorbed by the buffer portion2143. When the sealing pin214cools and shrinks, the bent part of the buffer portion2143deforms toward the welding portion2142, which can alleviate the deformation of the welding portion2142. Such an arrangement can effectively prevent the sealing pin214from cracking, so as to avoid the sealing failure of the sealing pin214due to the welding stress.

In an optional embodiment, as shown inFIG.7, the buffer portion2143is arched from the main body portion2141toward the second recess2113.

The buffer portion2143is arched toward the second recess2113and located in the second recess2113, is engaged with the inner wall of the second recess2113, and can achieve the limiting effect when the sealing pin214is aligned with the second recess2113, which is convenient for the sealing pin214to quickly align with the second recess2113during mounting, thereby improving the production efficiency.

In an optional embodiment, the side wall of the second recess2113is an inclined surface, and the buffer portion2143has gaps from the inclined surface and the bottom surface of the second recess2113.

Since the buffer portion2143has gaps from the inclined surface and the bottom surface of the second recess2113, on the one hand, the gaps can relieve part of the stress when being impacted, so as to avoid interference with the buffer portion2143; and on the other hand, providing the gaps can also reduce the air pressure in the closed space between the sealing pin214and the cover plate211. The buffer portion2143having gaps from the inclined surface and the bottom surface of the second recess2113can ensure the welding portion2142to be in effective contact with the bottom surface of the first recess2112, and is also conducive to discharge of the vapor generated by the electrolyte during welding to the outside via the gaps, so as to avoid the influence of the waste gas on the welding to prevent the occurrence of false welding of the welding seam2144, thereby ensuring the welding sealing performance of the sealing pin214. The gap that is too small will not be sufficient to relieve the welding stress, and the gap that is too large will affect the welding. Therefore, the size of the gap needs to be defined.

In an optional embodiment, more than one welding seam2144is welded between the welding portion2142and the welding surface.

The welding seam2144is the joint formed at the welding part after welding. Considering that poor welding is easily caused by various factors during the welding process, in order to avoid poor welding sealing performance when one welding is provided, the space for more than two welding seams2144in width is reserved at the welding portion2142. If poor welding occurs at one welding seam2144, a further welding seam2144can be provided for repair welding on the inner side. That is to say, the welding portion2142may include two situations, one is that there is only one welding seam2144on the welding portion2142, and the other is that there are two welding seams2144on the welding portion2142. Providing more than two welding seams2144can improve the welding sealing performance between the sealing pin214and the filling port2111.

In an optional embodiment, the bottom surface of the first recess2112is a horizontal surface or an inclined surface. The bottom surface of the first recess2112is attached to the bottom surface of the welding portion2142, and the welding operation needs to be performed on the bottom surface of the first recess2112. The welding can be operated when the bottom surface of the first recess2112is a horizontal surface or an inclined surface. The horizontal surface has no dead corner to be cleaned and is thus easier to clean and has less residual electrolyte, which can avoid the affection on the welding quality due to the residual electrolyte absorbing the heat and generating gas during welding. The inclined surface refers to a surface that forms a certain angle with respect to the horizontal plane. In some other embodiments, the bottom surface of the first recess2112is an inclined surface which is inclined from high to low toward the filling port2111, and the bottom surface of the welding portion2142is attached to the inclined surface.

With this arrangement, part of the liquid metal and molten metal will flow toward the filling port2111, resulting in a larger welding area.

In an optional embodiment, the angle of the bottom surface of the first recess2112with respect to the horizontal plane is 0° to 10°. As shown inFIG.8, A is an angle of the bottom surface of the first recess2112with respect to the horizontal plane. In this case, the angle A of the bottom surface of the first recess2112with respect to the horizontal plane is 10°. Accordingly, the angle of the bottom surface of the welding portion2142with respect to the horizontal plane is also 10°. In general, the angle between a welding rod and the weldment will affect the welding quality to a certain extent. During welding of the bottom surface of the first recess2112and the bottom surface of the welding portion2142of the sealing pin214, allowing the bottom surface of the first recess2112to be nearly level facilitates controlling the welding angle, so as to control the temperature of the weld pool, which can achieve a flat shape after welding and also avoid the formation of weld beading or heaviness. Compared with welding on the inclined surface, the liquid slag and metal on the horizontal surface are not easy to flow, so that it is easy to control the shape and size of the welding seam2144to achieve good appearance and high quality. In addition, welding on a horizontal surface allows for larger currents and higher work efficiency. A larger weld pool may be formed during welding, and in the weld pool, the slag melt and the liquid metal react uniformly, which can produce a good crystal structure.

In the specific operation process, after the secondary filling of cells and the insertion of plastic pins, the residual electrolyte around the filling port2111is firstly removed with paper tape, and the filling port2111is further cleaned by means of laser. The plastic pins are inserted. At this time, since the welding portion2142is away from the heavily contaminated region at the bevel, pinholes and burst points can be reduced theoretically.

When a welding defect occurs in the main welding seam, the welding track may be reduced, and an alternative welding seam may be formed in the inner circle of the first recess2112. Providing the alternative welding seam can achieve good sealing, thereby improving the welding yield. If the main welding seam has good welding quality, there is no need to provide the alternative welding seam.

Finally, it should be noted that the above embodiments are merely used for illustrating rather than limiting the technical solutions of the present application. Although the present application has been illustrated in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features thereof may be equivalently substituted; and such modifications or substitutions do not make the essence of the corresponding technical solution depart from the scope of the technical solutions of the embodiments of the present application, and should fall within the scope of the claims and the description of the present application. In particular, the technical features mentioned in the embodiments can be combined in any manner, provided that there is no structural conflict. The present application is not limited to the specific embodiments disclosed herein but includes all the technical solutions that fall within the scope of the claims.