CN216354651U

CN216354651U - Utmost point ear welded structure, battery monomer and consumer

Info

Publication number: CN216354651U
Application number: CN202122639778.5U
Authority: CN
Inventors: 陈从胜; 林文法; 温耀铃; 林江; 唐鸣浩; 林嘉
Original assignee: Contemporary Amperex Technology Co Ltd
Current assignee: Contemporary Amperex Technology Co Ltd
Priority date: 2021-10-29
Filing date: 2021-10-29
Publication date: 2022-04-19
Anticipated expiration: 2031-10-29

Abstract

The embodiment of the application provides a utmost point ear welded structure, battery monomer and consumer belongs to battery technical field. The tab welding structure includes a conductive member and a tab formed by laminating a plurality of sheets in a first direction. The conductive piece is welded with the tab to form a fusion area. Wherein the fused region includes a first fused portion and a second fused portion. The first fusing part extends from the tab into the conductive member along a first direction. The second fusing part is located at a side of the first fusing part, and the second fusing part is configured to connect the first fusing part and the tab. The second fusion portion plays the effect of connecting first fusion portion and utmost point ear, and the portion of fusing that passes through the second in the same place is equivalent to first fusion portion and utmost point ear, reduces utmost point ear because of direct and the first risk that fuses and lead to the fracture that links to each other, improves utmost point ear and the fastness of electrically conductive after welding, has improved the free life of battery.

Description

Utmost point ear welded structure, battery monomer and consumer

Technical Field

The application relates to the technical field of batteries, in particular to a tab welding structure, a battery monomer and electric equipment.

Background

Energy conservation and emission reduction are the key points of sustainable development of the automobile industry, and electric vehicles become important components of the sustainable development of the automobile industry due to the advantages of energy conservation and environmental protection. For electric vehicles, battery technology is an important factor in its development.

For a general battery cell, a tab is welded to a conductive member (current collecting member, electrode terminal, etc.) so as to output electric energy of the battery cell. At present, the phenomenon that the lug and the conductive piece fall off easily occurs after the lug and the conductive piece are welded, and the service life of a battery monomer is influenced.

SUMMERY OF THE UTILITY MODEL

The embodiment of the application provides a utmost point ear welded structure, battery monomer and consumer can effectively improve utmost point ear and the fastness of the post-weld of electrically conductive piece.

In a first aspect, an embodiment of the present application provides a tab welding structure, including: a tab formed by laminating a plurality of sheets in a first direction; the conductive piece is welded with the lug to form a fusion area; wherein the fused region comprises: a first fusing part extending from the tab into the conductive member in the first direction; a second fusion part interfacing with the first fusion part, the second fusion part being located at a side of the first fusion part, the second fusion part being configured to connect the first fusion part and the tab.

Among the above-mentioned technical scheme, the second fusion portion is located the lateral part of first fusion portion, and the second fusion portion plays the effect of connecting first fusion portion and utmost point ear, and the part of fusing through the second is in the same place with utmost point ear in first fusion portion, reduces utmost point ear because of directly linking to each other with first fusion portion and lead to the risk of fracture, improves utmost point ear and the fastness of the welding back of leading to electrical, has improved the free life of battery.

In some embodiments, a fusion depth of the second fusion portion is less than a fusion depth of the first fusion portion in the first direction.

In the above technical solution, the fusion depth of the second fusion part is smaller than the fusion depth of the first fusion part, so that the first fusion part has a relatively long dimension in the first direction and the second fusion part has a relatively short dimension in the second direction. The size of the first fusion part in the first direction is relatively long, the depth of the fusion area is large, and the firmness of the tab and the conductive piece after welding is guaranteed. The size of the second fusion part in the first direction is relatively short, and the second fusion part plays a good role in connecting the first fusion part and the tab, so that the risk of cracking of the tab welding position is reduced.

In some embodiments, in the first direction, the second fusing part does not extend beyond the tab in a direction in which the tab faces the conductive member.

Among the above-mentioned technical scheme, the second fuses the portion and does not surpass utmost point ear along the utmost point ear to the direction that electrically conducts for the second fuses the portion and does not extend to electrically conduct in, reduces because of the too big risk that causes the fracture to appear between second fusion portion and the utmost point ear of second fusion portion degree of depth.

In some embodiments, the welding temperature at which the conductive member and the tab are welded to form the second fusion part is lower than the welding temperature at which the conductive member and the tab are welded to form the first fusion part.

Among the above-mentioned technical scheme, the welding temperature that forms the second fusion portion is less than the welding temperature that forms first fusion portion, can make the degree of depth of first fusion portion be greater than the degree of depth of second fusion portion, and the degree of depth in fusion district is great, guarantees the fastness after utmost point ear and the welding of electrically conductive piece. Because the welding temperature that forms the second fusion portion is lower relatively, at the in-process that forms the second fusion portion, the difficult expansion deformation of utmost point ear has reduced the risk that second fusion portion and utmost point ear hookup location appear the fracture.

In some embodiments, the second fused portion is disposed on an outer peripheral side of the first fused portion, the second fused portion being distributed along a circumferential extension of the first fused portion.

Among the above-mentioned technical scheme, the second fuses the portion and is located the periphery side of first fusion portion, and extends the distribution along the circumference of first fusion portion, and the utmost point ear is all difficult for splitting in a plurality of azimuths of first fusion portion, improves the fastness after utmost point ear and the welding of electrically conductive piece.

In some embodiments, the tab is stacked on the conductive member in the first direction, and the first fused portion penetrates the tab and partially extends into the conductive member.

Among the above-mentioned technical scheme, utmost point ear and the electric piece of conducting stack up the setting in the first direction, and first fusion portion pierces through utmost point ear and local extension to the electric piece in for utmost point ear and the electric piece of conducting have fine fastness after the welding. The tab and the conductive piece can be welded in a penetration welding mode to form a first fusion part and a second fusion part, and the welding difficulty is reduced.

In some embodiments, in a second direction, at least one side of the first fusion is provided with the second fusion; wherein the second direction is perpendicular to the first direction.

Among the above-mentioned technical scheme, first fusion portion is provided with the second fusion portion in at least one side of second side, and the second fusion portion plays the effect of connecting first fusion portion and utmost point ear in one side or both sides of first fusion portion in the second side, has simplified welding process, has improved welding efficiency.

In some embodiments, the conductive member includes: a body portion having an abutting surface; the convex part protrudes out of the abutting surface; the tab abuts against the abutting surface along the first direction, a welding seam is formed between the tab and the convex part in the second direction, the fusion area is formed in the welding seam, and the second direction is perpendicular to the first direction.

Among the above-mentioned technical scheme, utmost point ear supports by in the face of supporting of this somatic part, forms the weld joint between utmost point ear and the convex part, and the fusion district is formed in the weld joint, realizes the joint welding that strides of utmost point ear and electrically conductive. Because the fusion zone is formed at the welding seam between the welding lug and the convex part, the heat influence on the lug during welding is small, and the risk of cracking at the connecting position of the second fusion part and the lug is reduced.

In a second aspect, embodiments of the present application provide a battery cell, including the tab welding structure provided in any one of the above embodiments.

In some embodiments, the battery cell includes an electrode terminal electrically connected to the tab, the electrode terminal being the conductive member.

In some embodiments, the battery cell includes: an electrode terminal; and the current collecting component is used for connecting the electrode terminal and the lug so as to realize the electric connection of the electrode terminal and the lug, and the current collecting component is the conductive piece.

In a third aspect, an embodiment of the present application provides a battery, including: the battery cell provided in any one of the above embodiments; and the box body is used for accommodating the battery monomer.

In a fourth aspect, an embodiment of the present application provides an electric device, including the battery provided in any one of the above embodiments.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are required to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained from the drawings without inventive effort.

FIG. 1 is a schematic illustration of a vehicle according to some embodiments of the present application;

fig. 2 is a schematic structural diagram of a battery provided in some embodiments of the present application;

fig. 3 is an exploded view of a battery cell provided in some embodiments of the present application;

fig. 4 is a cross-sectional view of a tab welding structure provided in accordance with some embodiments of the present application;

fig. 5 is a plan view of the tab welding structure shown in fig. 4;

fig. 6 is a cross-sectional view of a tab welding structure provided in accordance with further embodiments of the present application;

fig. 7 is a plan view of the tab welding structure shown in fig. 6;

fig. 8 is a view illustrating a structure of welding a tab and an electrode terminal of a battery cell according to some embodiments of the present application;

fig. 9 is a view illustrating a structure of welding a tab and an electrode terminal of a battery cell according to still other embodiments of the present application;

fig. 10 is a flow chart of a method of welding a tab provided in accordance with some embodiments of the present application;

fig. 11 is a flow chart of a method of welding a tab according to further embodiments of the present application;

fig. 12 is a diagram illustrating welding traces of a conductive element and a tab according to some embodiments of the present application;

fig. 13 is a schematic block diagram of a tab welding apparatus provided in some embodiments of the present application.

Icon: 10-a box body; 11-a first part; 12-a second part; 20-a battery cell; 21-a housing; 22-an electrode assembly; 23-end caps; 231-electrode terminals; 24-a pressure relief mechanism; 25-tab welding structure; 251-a conductive member; 2511-body part; 2511 a-an abutment surface; 2512-a protrusion; 2513-welding a seam; 252-a tab; 253-a fused zone; 2531-first fused portion; 2532-second fuse section; 100-a battery; 200-a controller; 300-a motor; 1000-a vehicle; 2000-welding equipment; 2100-a first providing device; 2200-a second providing means; 2300-a welding device; a-auxiliary welding track; b-main welding track; z-a first direction; x-a second direction.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used in the description of the application in the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application; the terms "including" and "having," and any variations thereof, in the description and claims of this application and the description of the above figures are intended to cover non-exclusive inclusions. The terms "first," "second," and the like in the description and claims of this application or in the above-described drawings are used for distinguishing between different elements and not for describing a particular sequential or chronological order.

Reference in the specification to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the specification. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments.

In the description of the present application, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "attached" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art as appropriate.

In the embodiments of the present application, like reference numerals denote like parts, and a detailed description of the same parts is omitted in different embodiments for the sake of brevity. It should be understood that the thickness, length, width and other dimensions of the various components in the embodiments of the present application and the overall thickness, length, width and other dimensions of the integrated device shown in the drawings are only exemplary and should not constitute any limitation to the present application.

The appearances of "a plurality" in this application are intended to mean more than two (including two).

In the present application, the battery cell may include a lithium ion secondary battery, a lithium ion primary battery, a lithium sulfur battery, a sodium lithium ion battery, a sodium ion battery, a magnesium ion battery, or the like, which is not limited in the embodiments of the present application. The battery cell may be a cylinder, a flat body, a rectangular parallelepiped, or other shapes, which is not limited in the embodiments of the present application. The battery cells are generally divided into three types in an encapsulation manner: the cylindrical battery monomer, the square battery monomer and the soft package battery monomer are also not limited in the embodiment of the application.

Reference to a battery in embodiments of the present application refers to a single physical module that includes one or more battery cells to provide higher voltage and capacity. For example, the battery referred to in the present application may include a battery module or a battery pack, etc. Batteries generally include a case for enclosing one or more battery cells. The box can avoid liquid or other foreign matters to influence the charging or discharging of battery monomer.

The battery monomer comprises an electrode assembly and electrolyte, wherein the electrode assembly comprises a positive pole piece, a negative pole piece and an isolating membrane. The battery cell mainly depends on metal ions to move between the positive pole piece and the negative pole piece to work. The positive pole piece includes anodal mass flow body and anodal active substance layer, and anodal active substance layer coats in anodal mass flow body's surface, and the anodal mass flow body protrusion in the anodal mass flow body that has coated anodal active substance layer of uncoated anodal active substance layer, and the anodal mass flow body that does not coat anodal active substance layer is as anodal utmost point ear. Taking a lithium ion battery as an example, the material of the positive electrode current collector may be aluminum, and the positive electrode active material may be lithium cobaltate, lithium iron phosphate, ternary lithium, lithium manganate, or the like. The negative pole piece includes negative pole mass flow body and negative pole active substance layer, and the negative pole active substance layer coats in the surface of negative pole mass flow body, and the negative pole mass flow body protrusion in the negative pole mass flow body of coating the negative pole active substance layer not coating the negative pole active substance layer, and the negative pole mass flow body of not coating the negative pole active substance layer is as negative pole utmost point ear. The material of the negative electrode current collector may be copper, and the negative electrode active material may be carbon, silicon, or the like. In order to ensure that the fuse is not fused when a large current is passed, the number of the positive electrode tabs is multiple and the positive electrode tabs are stacked together, and the number of the negative electrode tabs is multiple and the negative electrode tabs are stacked together. The material of the isolation film may be PP (polypropylene) or PE (polyethylene). In addition, the electrode assembly may have a winding structure or a lamination structure, and the embodiment of the present application is not limited thereto.

In the battery cell, the tab is generally welded to a conductive member (current collecting member, electrode terminal, etc.) so as to output electric energy of the battery cell.

The inventors found that a sufficient depth is required for a fused portion formed by welding a tab to a conductive member in order to secure the good firmness of the tab after welding the tab to the conductive member. However, the deeper the depth of the fusion part is, the higher the heat quantity received by the tab during welding is, and because the tab is formed by laminating a plurality of layers of sheets, the higher the temperature received by the tab is, the more easily the tab is subjected to expansion and deformation, so that the situation that the position where the tab is connected with the fusion part is cracked is caused, and the phenomenon that the conductive piece and the tab fall off easily occurs after the tab is welded with the conductive piece, thereby influencing the service life of the battery monomer.

In view of this, the present disclosure provides a tab welding structure in which a tab is welded to a conductive member to form a fusion region including a first fusion portion and a second fusion portion that are delimited from each other, the first fusion portion extending from the tab into the conductive member in a first direction, the second fusion portion being delimited from the first fusion portion, the second fusion portion being located at a side portion of the first fusion portion, the second fusion portion being configured to connect the first fusion portion and the tab.

In such utmost point ear welded structure, the second fusion portion plays the effect of connecting first fusion portion and utmost point ear, and the part of fusing is in the same place through the second fusion portion with utmost point ear in being equivalent to first fusion portion, reduces utmost point ear because of direct and the first risk that fuses and lead to the fracture that links to each other, improves utmost point ear and the fastness of the welding back of electrically conductive piece, has improved the free life of battery. In addition, as the fusion zone formed by welding the tab and the conductive piece comprises the first fusion part and the second fusion part, the flow area between the conductive piece and the tab is increased.

The technical scheme described in the embodiment of the application is suitable for the battery and the electric equipment using the battery.

The electric equipment can be vehicles, mobile phones, portable equipment, notebook computers, ships, spacecrafts, electric toys, electric tools and the like. The vehicle can be a fuel oil vehicle, a gas vehicle or a new energy vehicle, and the new energy vehicle can be a pure electric vehicle, a hybrid electric vehicle or a range-extended vehicle and the like; spacecraft include aircraft, rockets, space shuttles, and spacecraft, among others; electric toys include stationary or mobile electric toys, such as game machines, electric car toys, electric ship toys, electric airplane toys, and the like; the electric power tools include metal cutting electric power tools, grinding electric power tools, assembly electric power tools, and electric power tools for railways, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, electric impact drills, concrete vibrators, and electric planers. The embodiment of the present application does not specifically limit the above-mentioned electric devices.

For convenience of explanation, the following embodiments will be described by taking an electric device as an example of a vehicle.

Referring to fig. 1, fig. 1 is a schematic structural diagram of a vehicle 1000 according to some embodiments of the present disclosure, a battery 100 is disposed inside the vehicle 1000, and the battery 100 may be disposed at a bottom portion, a head portion, or a tail portion of the vehicle 1000. The battery 100 may be used for power supply of the vehicle 1000, for example, the battery 100 may serve as an operation power source of the vehicle 1000.

The vehicle 1000 may further include a controller 200 and a motor 300, the controller 200 being configured to control the battery 100 to supply power to the motor 300, for example, for starting, navigation, and operational power requirements while the vehicle 1000 is traveling.

In some embodiments of the present application, the battery 100 may be used not only as an operating power source of the vehicle 1000, but also as a driving power source of the vehicle 1000, instead of or in part of fuel or natural gas, to provide driving power for the vehicle 1000.

Referring to fig. 2, fig. 2 is a schematic structural diagram of a battery 100 according to some embodiments of the present disclosure, where the battery 100 includes a case 10 and a battery cell 20, and the case 10 is used for accommodating the battery cell 20.

The case 10 is a component for accommodating the battery cell 20, the case 10 provides an accommodating space for the battery cell 20, and the case 10 may have various structures. In some embodiments, the case 10 may include a first portion 11 and a second portion 12, and the first portion 11 and the second portion 12 cover each other to define a receiving space for receiving the battery cell 20. The first and second portions 11 and 12 may be in various shapes, such as rectangular parallelepiped, cylindrical, etc. The first portion 11 may be a hollow structure with one side open, the second portion 12 may also be a hollow structure with one side open, and the open side of the second portion 12 is covered on the open side of the first portion 11, thereby forming the box body 10 with a receiving space. The first portion 11 may have a hollow structure with one side opened, the second portion 12 may have a plate-like structure, and the second portion 12 may cover the opened side of the first portion 11 to form the case 10 having an accommodating space. The first part 11 and the second part 12 may be sealed by a sealing element, which may be a sealing ring, a sealant or the like.

In the battery 100, one or more battery cells 20 may be provided. If there are a plurality of battery cells 20, the plurality of battery cells 20 may be connected in series, in parallel, or in series-parallel, where in series-parallel refers to that the plurality of battery cells 20 are connected in series or in parallel. A plurality of battery cells 20 may be connected in series, in parallel, or in series-parallel to form a battery module, and a plurality of battery modules may be connected in series, in parallel, or in series-parallel to form a whole, and may be accommodated in the case 10. Or all the battery cells 20 may be directly connected in series or in parallel or in series-parallel, and the whole of all the battery cells 20 is accommodated in the case 10.

In some embodiments, the battery 100 may further include a bus member, and the plurality of battery cells 20 may be electrically connected to each other through the bus member, so as to connect the plurality of battery cells 20 in series or in parallel or in series-parallel. The bus member may be a metal conductor, such as copper, iron, aluminum, stainless steel, aluminum alloy, or the like.

Referring to fig. 3, fig. 3 is an exploded view of a battery cell 20 according to some embodiments of the present disclosure, in which the battery cell 20 includes a case 21, an electrode assembly 22, an end cap 23, and a conductive member 251.

The case 21 is a member for accommodating the electrode assembly 22, and the case 21 may be a hollow structure having one end formed with an opening. The housing 21 may be in various shapes, such as a cylinder, a rectangular parallelepiped, or the like. The material of the housing 21 may be various, such as copper, iron, aluminum, steel, aluminum alloy, etc.

One or more electrode assemblies 22 may be provided in the case 21. For example, as shown in fig. 3, the electrode assembly 22 is plural, and the plural electrode assemblies 22 are arranged in a stack.

The electrode assembly 22 is a component in the battery cell 20 where electrochemical reactions occur. The electrode assembly 22 may include a positive electrode tab, a negative electrode tab, and a separator. The electrode assembly 22 may have a winding type structure formed by winding a positive electrode tab, a separator, and a negative electrode tab, or a lamination type structure formed by laminating a positive electrode tab, a separator, and a negative electrode tab.

The positive electrode sheet may include a positive electrode current collector and positive electrode active material layers coated on opposite sides of the positive electrode current collector. The negative electrode tab may include a negative electrode current collector and a negative electrode active material layer coated on opposite sides of the negative electrode current collector. The electrode assembly 22 has a tab 252, and the tab 252 is divided into a positive tab 252 and a negative tab 252, the positive tab 252 may be a portion of the positive electrode sheet on which the positive active material layer is not coated, and the negative tab 252 may be a portion of the negative electrode sheet on which the negative active material layer is not coated.

The end cap 23 is a member that covers an opening of the case 21 to isolate the internal environment of the battery cell 20 from the external environment. The cap 23 covers an opening of the case 21, and the cap 23 and the case 21 together define a space for accommodating the electrode assembly 22, the electrolyte, and other components. The shape of the end cap 23 can be adapted to the shape of the housing 21, for example, the housing 21 has a rectangular parallelepiped structure, the end cap 23 has a rectangular plate structure adapted to the housing 21, and for example, the housing 21 has a cylindrical structure, and the end cap 23 has a circular plate structure adapted to the housing 21. The end cap 23 may be made of various materials, such as copper, iron, aluminum, steel, aluminum alloy, etc., and the material of the end cap 23 may be the same as or different from that of the housing 21.

The conductive member 251 is a member welded with the tab 252 to have a conductive capability, and the conductive member 251 is welded with the tab 252 to form a tab welded structure 25 (not shown in fig. 3). The conductive member 251 may be an electrode terminal 231 disposed on the end cap 23, and the conductive member 251 may also be a current collecting member connected between the tab 252 and the electrode terminal 231. If the conductive member 251 is the electrode terminal 231, the tab 252 is directly connected to the electrode terminal 231. If the conductive member 251 is a current collecting member, the tab 252 and the electrode terminal 231 are indirectly connected through the current collecting member. The conductive member 251 may be a metal conductor, such as copper, iron, aluminum, steel, aluminum alloy, etc.

In some embodiments, the battery cell 20 may further include a pressure relief mechanism 24, the pressure relief mechanism 24 being a component that relieves pressure inside the battery cell 20. The pressure relief mechanism 24 is disposed on the end cap 23, and when the pressure or temperature inside the battery cell 20 reaches a threshold value, the pressure inside the battery cell 20 is relieved through the pressure relief mechanism 24. The pressure relief mechanism 24 may be a component such as an explosion proof valve, an explosion proof disc, a pressure relief valve, or the like.

In some embodiments, battery cell 20 may further include an insulating member, which is a member separating end cap 23 from electrode assembly 22, disposed on a side of end cap 23 facing electrode assembly 22, and insulating separation of end cap 23 from electrode assembly 22 is achieved by the insulating member. The insulating member is made of insulating material, and the insulating member can be made of plastic, rubber and the like.

Referring to fig. 4, fig. 4 is a cross-sectional view of a tab welding structure 25 according to some embodiments of the present disclosure, where the tab welding structure 25 includes a conductive member 251 and a tab 252 formed by laminating a plurality of layers of sheets in a first direction Z. The conductive member 251 is welded with the tab 252 to form a fusion zone 253.

Wherein the fused region 253 includes a first fused portion 2531 and a second fused portion 2532. The first fusion portion 2531 extends from the tab 252 into the conductive member 251 in the first direction Z. The second fusion portion 2532 and the first fusion portion 2531 are demarcated from each other, the second fusion portion 2532 is located at a side of the first fusion portion 2531, and the second fusion portion 2532 is configured to connect the first fusion portion 2531 and the tab 252.

The tab 252 has a multi-layer structure, and the tab 252 is formed by laminating a plurality of layers of sheets along a first direction Z, which is the thickness direction of the sheets. Taking the electrode assembly 22 (shown in fig. 3) as an example of a winding structure, the pole pieces (positive pole piece, negative pole piece) will form a plurality of sub-tabs arranged at intervals in a sheet shape on one side in the front width direction before winding, and after winding the pole pieces, the plurality of sub-tabs are laminated together to form the tab 252. The sub-tabs may be sheets forming the tabs 252. The tab 252 may be welded together by welding multiple layers of sheets in the tab 252 before welding with the conductive member 251.

The conductive member 251 is a member welded with the tab 252 to form a fusion zone 253. In the battery cell 20, the conductive member 251 may be the electrode terminal 231, the current collecting member, etc.

The fusion zone 253 is a part where the conductive member 251 and the tab 252 are welded and fused together. The first fusion portion 2531 is a portion where the fusion region 253 connects the tab 252 and the conductive member 251, and the second fusion region 253 is a portion where the fusion region 253 connects the second fusion portion 2532 and the tab 252. The first and

second fusion portions

2531 and 2532 are demarcated from each other, and an interface is formed at a position where they are connected, and the first and

second fusion portions

2531 and 2532 are formed by two times of welding, respectively. The first and second fused

portions

2531 and 2532 have various boundary forms. For example, it may be that both the first and second fused

portions

2531 and 2532 are different in color so as to be demarcated from each other; it is also possible that the surface roughness of both the first and second fused

portions

2531 and 2532 are different so that they are demarcated from each other.

The second fusion portion 2532 is located the lateral part of the first fusion portion 2531, and the second fusion portion 2532 plays a role in connecting the first fusion portion 2531 and the tab 252, which is equivalent to the first fusion portion 2531 and the tab 252 are fused together through the second fusion portion 2532, thereby reducing the risk of the tab 252 cracking at the welding position due to the direct connection with the first fusion portion 2531, improving the firmness of the tab 252 after being welded with the conductive member 251, and prolonging the service life of the battery cell 20. In addition, since the fusing region 253 formed by welding the tab 252 to the conductive member 251 includes the first fusing portion 2531 and the second fusing portion 2532, an area of flow between the conductive member 251 and the tab 252 is increased.

In some embodiments, with continued reference to fig. 4, in the first direction Z, the fusion depth of the second fusion portion 2532 is less than the fusion depth of the first fusion portion 2531.

The fusion depth of the first fusion portion 2531 is a dimension of the first fusion portion 2531 in the first direction Z, and the fusion depth of the second fusion portion 2532 is a dimension of the second fusion portion 2532 in the first direction Z. The fusion depth of the second fusion portion 2532 is smaller than that of the first fusion portion 2531, so that the bottom end of the first fusion portion 2531 is located at a deeper position than the bottom end of the second fusion portion 2532.

Since the fusion depth of the second fusion portion 2532 is smaller than that of the first fusion portion 2531, the welding temperature when the pole ear 252 and the conductive member 251 are welded to form the second fusion portion 2532 will be lower than that when the pole ear 252 and the conductive member 251 are welded to form the first fusion portion 2531, the heat influence on the pole ear 252 is small during the formation of the second fusion portion 2532, and the pole ear 252 is not easily expanded by heat.

The first fusion portion 2531 has a relatively long dimension in the first direction Z, and the depth of the fusion area 253 is large, so as to ensure the firmness of the welded tab 252 and the conductive member 251. The second fusion portion 2532 is relatively short in size in the first direction Z, and the second fusion portion 2532 plays a good role in connecting the first fusion portion 2531 with the tab 252, so that the risk of cracking at the welding position of the tab 252 is reduced.

In some embodiments, with continued reference to fig. 4, in the first direction Z, the second fusion portion 2532 does not extend beyond the tab 252 along a direction in which the tab 252 faces the conductor 251.

As shown in fig. 4, taking the tab 252 located at the upper side of the conductive member 251 as an example, the second fusing portion 2532 does not extend beyond the tab 252 in a direction in which the tab 252 faces the conductive member 251, i.e., the bottom end of the second fusing portion 2532 is located in the tab 252, so that the fusing depth of the second fusing portion 2532 in the first direction Z is not excessively large.

The greater the fusion depth of the second fusion portion 2532, the greater the thermal influence on the tab 252 during the process of welding the tab 252 and the conductive member 251 to form the second fusion portion 2532, and the greater the tendency for expansion and cracking.

In this embodiment, the second fusing portion 2532 does not extend beyond the tab 252 in a direction in which the tab 252 faces the conductive member 251, so that the second fusing portion 2532 does not extend into the conductive member 251, and the risk of cracking between the second fusing portion 2532 and the tab 252 due to an excessively large depth of the second fusing portion 2532 is reduced.

In some embodiments, the welding temperature of the conductor 251 and the tab 252 to form the second fusion portion 2532 is lower than the welding temperature of the conductor 251 and the tab 252 to form the first fusion portion 2531.

In the process of welding the electrode tab 252 and the conductive member 251, the welding temperature for forming the second fusion portion 2532 is lower than the welding temperature for forming the first fusion portion 2531, which can be achieved by the welding power for forming the second fusion portion 2532 being lower than the welding power for forming the first fusion portion 2531. Taking the example that the tab 252 and the conductive member 251 are laser welded, the welding power for forming the first fusion portion 2531 by the first laser welding of the tab 252 and the conductive member 251 is the first welding power, the welding power for forming the second fusion portion 2532 by the second laser welding of the tab 252 and the conductive member 251 is the second welding power, and the second welding power is smaller than the first welding power.

In this embodiment, the welding temperature for forming the second fusion portion 2532 is lower than the welding temperature for forming the first fusion portion 2531, so that the depth of the first fusion portion 2531 is greater than the depth of the second fusion portion 2532, the depth of the fusion region 253 is greater, and the firmness of the tab 252 welded to the conductive member 251 is ensured. Due to the fact that the welding temperature for forming the second fusion portion 2532 is relatively low, the tab 252 is not prone to expansion and deformation in the process of forming the second fusion portion 2532, and the risk of cracking at the connection position of the second fusion portion 2532 and the tab 252 is reduced.

In some embodiments, referring to fig. 5, fig. 5 is a top view of the tab welding structure 25 shown in fig. 4, the second fusing portion 2532 is disposed on an outer peripheral side of the first fusing portion 2531, and the second fusing portion 2532 extends along a circumferential direction of the first fusing portion 2531.

The second fusion portion 2532 is provided on the outer peripheral side of the first fusion portion 2531, that is, the first fusion portion 2531 is located inside the second fusion portion 2532. The second fusion portions 2532 are distributed along the circumferential extension of the first fusion portions 2531, and the second fusion portions 2532 may be a full-surrounding structure extending along the circumferential extension of the first fusion portions 2531 and connected end to end, or a half-surrounding structure extending along the circumferential extension of the first fusion portions 2531 and spaced end to end.

In this embodiment, since the second fusion portion 2532 is located at the outer periphery of the first fusion portion 2531 and extends along the circumferential direction of the first fusion portion 2531, the tab 252 is not easily cracked in a plurality of directions of the first fusion portion 2531, and the firmness of the tab 252 welded to the conductive member 251 is improved.

In some embodiments, as shown in fig. 4 and 5, the tab 252 is stacked on the conductive member 251 in the first direction Z, and the first fusion portion 2531 penetrates the tab 252 and partially extends into the conductive member 251.

Taking the tab 252 located on the upper side of the conductive member 251 as an example, the first fusing portion 2531 penetrates the tab 252 from top to bottom, and the bottom of the first fusing portion 2531 extends into the conductive member 251, so that the first fusing portion 2531 is connected to the conductive member 251.

In the embodiment, the tab 252 and the conductive member 251 are stacked in the first direction Z, and the first fusion portion 2531 penetrates through the tab 252 and partially extends into the conductive member 251, so that the tab 252 and the conductive member 251 have good firmness after being welded. The tab 252 and the conductive member 251 may be welded by penetration welding to form a first fusion portion 2531 and a second fusion portion 2532, which reduces the welding difficulty.

In some embodiments, referring to fig. 6 and 7, fig. 6 is a cross-sectional view of a welding structure of a tab 252 according to still other embodiments of the present disclosure, and fig. 7 is a top view of the tab welding structure 25 shown in fig. 6, and at least one side of the first fusion portion 2531 is provided with a second fusion portion 2532 in the second direction X. Wherein the second direction X is perpendicular to the first direction Z.

The second direction X is perpendicular to the first direction Z, the first direction Z may be consistent with a direction of a fusion depth of the first fusion portion 2531, and the second direction X may be consistent with a width direction of the first fusion portion 2531. At least one side of the first fusion portion 2531 is provided with a second fusion portion 2532, only one side of the first fusion portion 2531 close to the tab 252 may be provided with the second fusion portion 2532, or both one side of the first fusion portion 2531 close to the tab 252 and one side far away from the tab 252 may be provided with the second fusion portion 2532. Illustratively, in fig. 6 and 7, in the second direction, the side of the first fusion portion 2531 close to the tab 252 is provided with the second fusion portion 2532, and the side of the first fusion portion 2531 away from the tab 252 is not provided with the second fusion portion 2532.

In this embodiment, at least one side of the first fusion portion 2531 in the second direction X is provided with a second fusion portion 2532, and the second fusion portion 2532 plays a role in connecting the first fusion portion 2531 and the tab 252 at one side or both sides of the first fusion portion 2531 in the second direction X, so that the welding process is simplified, and the welding efficiency is improved.

In some embodiments, as shown in fig. 6 and 7, the conductive member 251 includes a body portion 2511 and a protrusion 2512. The body portion 2511 has an abutment surface 2511 a. The convex portion 2512 protrudes from the abutting surface 2511 a. The tab 252 abuts against the abutting surface 2511a in the first direction Z, a weld 2513 is formed between the tab 252 and the convex portion 2512 in the second direction X, the fusion zone 253 is formed at the weld 2513, and the second direction X is perpendicular to the first direction Z.

The abutting surface 2511a is a surface of the body 2511 against which the tab 252 abuts, and the abutting surface 2511a is a flat surface. The second direction X is perpendicular to the first direction Z, and the second direction X may be consistent with a width direction of the first fusion portion 2531.

Illustratively, as shown in fig. 6, the second fusing portion 2532 is located on one side of the first fusing portion 2531 adjacent to the tab 252 in the second direction X. In the first direction Z, the fusion depth of the second fusion portion 2532 is less than that of the first fusion portion 2531, the bottom end of the second fusion portion 2532 is located in the tab 252, and the bottom end of the first fusion portion 2531 extends into the conductive member 251.

In the present embodiment, the tab 252 abuts against the abutting surface 2511a of the body 2511, a weld 2513 is formed between the tab 252 and the protrusion 2512, and the fusion zone 253 is formed at the weld 2513, so that the tab 252 and the conductive member 251 are subjected to seam welding. Due to the formation of the fusion zone 253 at the weld joint 2513 between the welding tab 252 and the convex portion 2512, the tab 252 is subjected to a small thermal influence during welding, and the risk of cracking at the connection position of the second fusion portion 2532 and the tab 252 is reduced.

The embodiment of the present application provides a battery cell 20, which includes the tab welding structure 25 provided in any one of the above embodiments.

In some embodiments, referring to fig. 8 and 9, fig. 8 is a structural view illustrating a welding structure of a tab 252 and an electrode terminal 231 of a battery cell 20 according to some embodiments of the present disclosure, and fig. 9 is a structural view illustrating a welding structure of a tab 252 and an electrode terminal 231 of a battery cell 20 according to yet other embodiments of the present disclosure, where the battery cell 20 includes an electrode terminal 231, the electrode terminal 231 is electrically connected to the tab 252, and the electrode terminal 231 is a conductive member 251.

In fig. 8, a fusion zone 253 is formed between the tab 252 and the electrode terminal 231 by penetration welding. In fig. 9, the tab 252 and the electrode terminal 231 are formed into a fusion zone 253 by a stitch welding.

As shown in fig. 8 and 9, in the embodiment in which a plurality of electrode assemblies 22 (shown in fig. 3) are included in the battery cell 20, a tab 252 (e.g., a positive tab 252) of one portion of the electrode assemblies 22 is welded to the electrode terminal 231, and a tab 252 (e.g., a positive tab 252) of the other portion of the electrode assemblies 22 is welded to the electrode terminal 231.

In other embodiments, the battery cell 20 includes an electrode terminal 231 and a current collecting member for connecting the electrode terminal 231 and the tab 252 to electrically connect the electrode terminal 231 and the tab 252, and the current collecting member is a conductive member 251.

The embodiment of the application provides a battery 100, which comprises a box body 10 and a battery cell 20 provided by any one of the above embodiments. The case 10 is used to accommodate the battery cells 20.

The embodiment of the present application provides an electric device, including the battery 100 provided in any one of the above embodiments.

The powered device may be any of the devices described above that employ battery 100.

Referring to fig. 10, fig. 10 is a flowchart illustrating a method for welding a tab 252 according to some embodiments of the present application, where the method includes:

s100: providing the electrode assembly 22 having the tab 252, the tab 252 being formed by laminating a plurality of sheets in the first direction Z;

s200: providing a conductive member 251;

s300: the tab 252 is welded to the conductive member 251 and a fused region 253 is formed.

After the tab 252 is welded with the conductive piece 251 by the method, the first fusing part 2531 and the tab 252 are fused together through the second fusing part 2532, so that the risk of cracking of the welding position of the tab 252 caused by the fact that the tab 252 is directly connected with the first fusing part 2531 is reduced, the firmness of the welded tab 252 and the conductive piece 251 is improved, and the service life of the battery unit 20 is prolonged. In addition, since the fusing region 253 formed by welding the tab 252 to the conductive member 251 includes the first fusing portion 2531 and the second fusing portion 2532, an area of flow between the conductive member 251 and the tab 252 is increased.

In the above method, the sequence of step S100 and step S200 is not limited. Step S100 may be executed first, and then step S200 may be executed, or step S200 may be executed first, and then step S100 may be executed.

In some embodiments, referring to fig. 11, fig. 11 is a flowchart of a method for welding a tab 252 according to still other embodiments of the present application, and step S300 includes:

s310: performing main welding on the tab 252 and the conductive member 251 to form a first fusion portion 2531;

s320: the tab 252 is secondarily welded to the conductive member 251 to form a second fusion portion 2532.

Wherein the welding temperature of the auxiliary welding is lower than that of the main welding.

In the embodiment of the present application, the sequence of step S310 and step S320 is not limited. Step S310 may be performed first, and then step S320 may be performed, for example, first, the tab 252 and the conductive member 251 are primarily welded to form a first fusion portion 2531, and then, the edge of the first fusion portion 2531 is secondarily welded to form a second fusion portion 2532 connecting the first fusion portion 2531 and the tab 252 together; step S320 may be performed first, and step S310 may be performed second, for example, the tab 252 and the conductive member 251 are welded together to form the second fusion portion 2532, and then the edge of the second fusion portion 2532 is welded together to form the first fusion portion 2531 connecting the second fusion portion 2532 and the conductive member 251.

The welding temperature of the auxiliary welding is lower than that of the main welding, and the auxiliary welding can be realized by the welding power of the auxiliary welding being lower than that of the main welding. Taking the example that the tab 252 and the conductive member 251 are laser welded, the welding power for forming the second fusion portion 2532 by laser auxiliary welding is less than that for forming the first fusion portion 2531 by laser main welding.

In this embodiment, the welding temperature for the main welding of the tab 252 and the conductive member 251 is relatively high, so that the depth of the first fusion portion 2531 is relatively deep, and the firmness of the tab 252 and the conductive member 251 after welding is ensured. The welding temperature for auxiliary welding of the tab 252 and the conductive member 251 is relatively low, and in the process of forming the second fusion portion 2532, the tab 252 is not easy to expand and deform, so that the risk of cracking at the connection position of the second fusion portion 2532 and the tab 252 is reduced.

In some embodiments, the auxiliary welding of the conductor 251 and the tab 252 includes: the tab 252 and the conductive member 251 are welded several times from the inside to the outside in the circumferential direction to form a second fusion portion 2532.

Referring to fig. 12, fig. 12 is a diagram of welding tracks of a conductive element 251 and a tab 252 according to some embodiments of the present disclosure, when the conductive element 251 and the tab 252 are welded secondarily, the welding can be performed along a secondary welding track a from inside to outside; when the conductive member 251 and the tab 252 are primarily welded, welding may be performed in a spiral manner along the primary welding track B.

The tab 252 and the conductive member 251 are welded in a plurality of circles along the circumferential direction, so that a second fusion portion 2532 extending and distributed along the circumferential direction of the first fusion portion 2531 can be formed, the tab 252 is not prone to cracking in a plurality of directions of the first fusion portion 2531, and the firmness of the tab 252 and the conductive member 251 after welding is improved.

In some embodiments, the welding temperature of each turn is stepped down from inside to outside.

In the process of welding the tab 252 and the conductive member 251 for multiple circles from inside to outside along the circumferential direction to form the second fusion portion 2532, the welding temperature of each circle is gradually reduced from inside to outside, so that the fusion depth of the second welding portion is reduced in a step shape from inside to outside, the thermal influence on the tab 252 caused by each circle of welding from inside to outside is gradually reduced, and the risk of cracking at the connection position of the second fusion portion 2532 and the tab 252 is further reduced.

The embodiment of the present application also provides a welding apparatus 2000 for a tab 252, please refer to fig. 13, where fig. 13 is a schematic block diagram of the welding apparatus 2000 for the tab 252 provided in some embodiments of the present application, and the welding apparatus 2000 includes a first providing device 2100, a second providing device 2200, and a welding device 2300.

The first providing device 2100 is used to provide the electrode assembly 22 having the tab 252, and the tab 252 is formed by laminating a plurality of sheets in the first direction Z. The first providing device 2100 is used for providing the conductive member 251. The welding device 2300 is used to weld the tab 252 to the conductor 251 so that the tab 252 and the conductor 251 form a fused region 253.

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict.

The above embodiments are merely for illustrating the technical solutions of the present application and are not intended to limit the present application, and those skilled in the art can make various modifications and variations of the present application. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A tab welding structure, comprising:

a tab formed by laminating a plurality of sheets in a first direction;

the conductive piece is welded with the lug to form a fusion area;

wherein the fused region comprises:

a first fusing part extending from the tab into the conductive member in the first direction;

a second fusion part interfacing with the first fusion part, the second fusion part being located at a side of the first fusion part, the second fusion part being configured to connect the first fusion part and the tab.

2. The tab welding structure as claimed in claim 1, wherein the second fusing part has a fusing depth smaller than that of the first fusing part in the first direction.

3. The tab welding structure according to claim 1, wherein the second fusion portion does not extend beyond the tab in a direction in which the tab faces the conductive member in the first direction.

4. The tab welding structure according to claim 1, wherein a welding temperature at which the conductive member and the tab are welded to form the second fusion portion is lower than a welding temperature at which the conductive member and the tab are welded to form the first fusion portion.

5. The tab welding structure according to any one of claims 1 to 4, wherein the second fusion portion is provided on an outer peripheral side of the first fusion portion, the second fusion portion being distributed along a circumferential extension of the first fusion portion.

6. The tab welding structure according to claim 5, wherein the tab is stacked on the conductive member in the first direction, and the first fusion portion penetrates the tab and partially extends into the conductive member.

7. The tab welding structure according to any one of claims 1 to 4, wherein at least one side of the first fusion is provided with the second fusion in a second direction;

wherein the second direction is perpendicular to the first direction.

8. The tab welding structure according to claim 7, wherein the conductive member comprises:

a body portion having an abutting surface;

the convex part protrudes out of the abutting surface;

the tab abuts against the abutting surface along the first direction, a welding seam is formed between the tab and the convex part in the second direction, the fusion area is formed in the welding seam, and the second direction is perpendicular to the first direction.

9. A battery cell characterized by comprising the tab welding structure according to any one of claims 1 to 8.

10. The battery cell as set forth in claim 9, wherein the battery cell includes an electrode terminal electrically connected to the tab, the electrode terminal being the conductive member.

11. The battery cell of claim 9, wherein the battery cell comprises:

an electrode terminal;

and the current collecting component is used for connecting the electrode terminal and the lug so as to realize the electric connection of the electrode terminal and the lug, and the current collecting component is the conductive piece.

12. A battery, comprising:

a battery cell according to any one of claims 9-11;

and the box body is used for accommodating the battery monomer.

13. An electrical device comprising the battery of claim 12.