Tab welding structure, battery cell, power consumption device, tab welding method and tab welding device

Abstract

The embodiments of the present application provide a tab welding structure, a battery cell, and a power consumption device, which belong to the field of battery technology. The tab welding structure includes a conductive member and a tab formed by stacking a plurality of layers of sheets along a first direction. The conductive member and the tab are welded to form a fusion region. Here, the fusion region includes a first fusion portion and a second fusion portion. The first fusion portion extends from the tab into the conductive member along the first direction. The second fusion portion is partitioned from the first fusion portion, the second fusion portion is located on a side of the first fusion portion, and the second fusion portion is configured to connect the first fusion portion and the tab. The second fusion portion serves to connect the first fusion portion and the tab, which corresponds to the first fusion portion and the tab being fused through the second fusion portion, thereby reducing the risk of cracks caused by the tab being directly connected to the first fusion portion, improving the robustness after welding between the tab and the conductive member, and improving the service life of the battery cell.

Description

[Technical field]

[0001] The present application relates to the field of battery technology, in particular to tab welding structures, battery cells 、 power consumption equipment , tab welding method and tab welding equipment Regarding. [Background technology]

[0002] Energy conservation and emission reduction are key to the sustainable development of the automotive industry, and electric vehicles have become an important part of this due to their energy-saving and environmental advantages. Battery technology is a key element in the development of electric vehicles.

[0003] In a typical battery cell, the tab is welded to a conductive member (such as a current collector or electrode terminal) to output the electrical energy of the battery cell. Currently, after the tab and the conductive member are welded together, the tab and the conductive member are likely to fall off, which affects the service life of the battery cell. Summary of the Invention

[0004] The embodiments of the present application provide a tab welding structure, a battery cell, and a power consuming device that can effectively improve the robustness after welding between the tab and the conductive member.

[0005] According to a first aspect, an embodiment of the present application provides a tab welding structure, the tab welding structure including a tab formed by stacking multiple layers of sheets along a first direction, and a conductive member welded to the tab to form a fusion region, wherein the fusion region includes a first fusion portion extending from the tab into the conductive member along the first direction, and a second fusion portion mutually partitioned from the first fusion portion, located on a side of the first fusion portion, and configured to connect the first fusion portion and the tab.

[0006] In the above technical solution, the second fusion part is located on the side of the first fusion part, and the second fusion part serves to connect the first fusion part and the tab, which is equivalent to the first fusion part and the tab being fused through the second fusion part, thereby reducing the risk of cracks caused by the tab being directly connected to the first fusion part, improving the robustness after welding between the tab and the conductive member, and improving the service life of the battery cell.

[0007] In some embodiments, a blend depth of the second blend portion in the first direction is less than a blend depth of the first blend portion.

[0008] In the above technical solution, the fusion depth of the second fusion portion is smaller than the fusion depth of the first fusion portion, so that the size of the first fusion portion in the first direction is relatively long, and the fusion depth of the second fusion portion is relatively long. 1 The size in the first direction of the first fusion portion is relatively short. The size in the first direction of the first fusion portion is relatively long, and the depth of the fusion region is large, ensuring robustness after welding the tab and the conductive member. The size in the first direction of the second fusion portion is relatively short, and the second fusion portion serves to provide a good connection between the first fusion portion and the tab, reducing the risk of cracks at the tab welding position.

[0009] In some embodiments, in the first direction, the second blend portion does not extend beyond the tab along a direction in which the tab faces the conductive member.

[0010] In the above technical solution, the second fusion portion does not protrude from the tab in the direction toward the conductive member, so that the second fusion portion does not extend into the conductive member, reducing the risk of the second fusion portion being too deep and causing cracks to occur between the second fusion portion and the tab.

[0011] In some embodiments, a welding temperature at which the conductive member and the tab are welded to form the second fusion zone is less than a welding temperature at which the conductive member and the tab are welded to form the first fusion zone.

[0012] In the above technical solution, the welding temperature for forming the second fusion part is lower than the welding temperature for forming the first fusion part, so that the depth of the first fusion part is greater than the depth of the second fusion part, and the depth of the fusion area is large, so that the robustness after welding the tab and the conductive member can be ensured. Since the welding temperature for forming the second fusion part is relatively low, the tab is less likely to expand and deform in the process of forming the second fusion part, and the risk of cracks occurring at the connection position between the second fusion part and the tab is reduced.

[0013] In some embodiments, the second fusion portion is disposed on an outer peripheral side of the first fusion portion, and the second fusion portion is distributed extending along a circumferential direction of the first fusion portion.

[0014] In the above technical solution, the second fusion portion is located on the outer circumferential side of the first fusion portion and extends and distributes along the circumferential direction of the first fusion portion, making the tab less susceptible to cracking in multiple directions of the first fusion portion, thereby improving the robustness after welding between the tab and the conductive member.

[0015] In some embodiments, in the first orientation, the tab is positioned in a stacked relationship with the conductive member, and the first fusion portion extends locally through the tab and into the conductive member.

[0016] In the above technical solution, the tab is disposed in a stacked manner with the conductive member in a first direction, and the first fusion portion penetrates the tab and extends locally into the conductive member, so that the tab and the conductive member have good robustness after being welded together. The tab and the conductive member may be welded together by penetration welding, thereby forming the first fusion portion and the second fusion portion, and reducing the difficulty of welding.

[0017] In some embodiments, the second blend portion is located on at least one side of the first blend portion in a second direction, where the second direction is perpendicular to the first direction.

[0018] In the above technical solution, a second fusion portion is installed on at least one side of the first fusion portion in the second direction, and the second fusion portion serves to connect the first fusion portion and the tab on one or both sides of the first fusion portion in the second direction, simplifying the welding process and improving the welding efficiency.

[0019] In some embodiments, the conductive member includes a body portion having an abutment surface and a protrusion protruding from the abutment surface, the tab abuts the abutment surface along the first direction, a weld bead is formed between the tab and the protrusion in a second direction, the fusion region is formed in the weld bead, and the second direction is perpendicular to the first direction.

[0020] In the above technical solution, the tab abuts against the abutment surface of the main body, a weld bead is formed between the tab and the protrusion, and a fusion region is formed in the weld bead to realize seam welding between the tab and the conductive member. Since the fusion region is formed in the weld bead between the weld tab and the protrusion, the tab is less affected by heat during welding, and the risk of cracks occurring at the connection position between the second fusion region and the tab is reduced.

[0021] According to a second aspect, an embodiment of the present application provides a battery cell, the battery cell including a tab welding structure according to any one of the above embodiments.

[0022] In some embodiments, the battery cell includes an electrode terminal electrically connected to the tab, the electrode terminal being the conductive member.

[0023] In some embodiments, the battery cell includes an electrode terminal and a current collecting part that is the conductive member for connecting the electrode terminal and the tab to realize an electrical connection between the electrode terminal and the tab.

[0024] According to a third aspect, an embodiment of the present application provides a battery, the battery including a battery cell according to any one of the above embodiments, and a housing for housing the battery cell.

[0025] According to a fourth aspect, an embodiment of the present application provides a power consumer device, the power consumer device including a battery according to any one of the above embodiments.

[0026] According to a fifth aspect, an embodiment of the present application provides a method for welding a tab, the method including: providing an electrode assembly having a tab formed by stacking multiple layers of sheets along a first direction; providing a conductive member; and welding the tab and the conductive member to form a fusion region, wherein the fusion region includes a first fusion portion extending from the tab into the conductive member along the first direction, and a second fusion portion mutually spaced from the first fusion portion, located on a side of the first fusion portion, and configured to connect the first fusion portion and the tab.

[0027] In some embodiments, welding the tab and the conductive member to form the fused region includes primarily welding the tab and the conductive member to form the first fused portion and secondarily welding the tab and the conductive member to form the second fused portion, wherein a welding temperature of the secondary weld is less than a welding temperature of the primary weld.

[0028] In the above technical proposal, the welding temperature for the primary welding between the tab and the conductive member is relatively high, so that the depth of the first fusion part is relatively deep, and the robustness after welding between the tab and the conductive member is ensured. The welding temperature for the secondary welding between the tab and the conductive member is relatively low, so that the tab is less likely to expand and deform in the process of forming the second fusion part, and the risk of cracks occurring at the connection position between the second fusion part and the tab is reduced.

[0029] In some embodiments, the second welding of the tab and the conductive member includes circumferentially welding the tab and the conductive member in a multi-ring fashion from inside to outside to form the second fused portion.

[0030] In the above technical proposal, by welding the tab and the conductive member together in a circumferential direction by multiple ring welding, a second fusion portion extending and distributed along the circumferential direction can be formed, making the tab less susceptible to cracking in multiple directions of the first fusion portion, thereby improving the robustness after welding between the tab and the conductive member.

[0031] In some embodiments, the welding temperature of each ring is stepped down from the inside to the outside.

[0032] In the above technical proposal, the welding temperature of each ring is gradually reduced from the inside to the outside, and the thermal impact on the tab caused by the welding of each ring from the inside to the outside is gradually reduced, further reducing the risk of cracks occurring at the connection position between the second fusion part and the tab.

[0033] According to a sixth aspect, an embodiment of the present application further provides a tab welding machine, the welding machine including a first providing device for providing an electrode assembly having a tab formed by stacking a plurality of layers of sheets along a first direction, and a second providing device for providing a conductive member. 2 and a welding device for welding the tab and the conductive member such that the tab and the conductive member form a fusion region, wherein the fusion region includes a first fusion portion extending from the tab into the conductive member along the first direction, and a second fusion portion spaced apart from the first fusion portion, located on a side of the first fusion portion, and configured to connect the first fusion portion and the tab. [Brief description of the drawings]

[0034] In order to more clearly explain the technical solutions of the embodiments of the present application, the following provides a brief description of the drawings that need to be used in the embodiments. It should be understood that the following drawings are only for illustrating some embodiments of the present application and should not be regarded as limiting the scope. Those skilled in the art can further obtain other related drawings based on these drawings without exerting creative efforts. [Figure 1] 1 is a structural schematic diagram of a vehicle according to some embodiments of the present application. [Diagram 2] 1 is a structural schematic diagram of a battery according to some embodiments of the present application. [Diagram 3] FIG. 2 is an exploded view of a battery cell according to some embodiments of the present application. [Figure 4] 1 is a cross-sectional view of a tab weld structure according to some embodiments of the present application. [Diagram 5] FIG. 5 is a top view of the tab welding structure shown in FIG. 4. [Figure 6] 4 is a cross-sectional view of a tab weld structure according to some further embodiments of the present application. [Figure 7] FIG. 7 is a top view of the tab welding structure shown in FIG. [Figure 8] 1 is a welding structure diagram of a tab and an electrode terminal of a battery cell according to some embodiments of the present application. FIG. [Figure 9] 11 is a welding structure diagram of a tab and an electrode terminal of a battery cell according to still other embodiments of the present application. FIG. [Figure 10] 4 is a flow chart of a method for welding a tab according to some embodiments of the present application. [Figure 11] 5 is a flow chart of a method for welding a tab according to still further embodiments of the present application. [Figure 12] 4 is a welding track diagram of a conductive member and a tab according to some embodiments of the present application. [Figure 13] FIG. 2 is a schematic block diagram of a tab welding apparatus according to some embodiments of the present application. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0035] In order to clarify the purpose, technical solutions and advantages of the embodiments of the present application, the technical solutions in the embodiments of the present application will be clearly described below in conjunction with the drawings of the embodiments of the present application. It is clear that the described embodiments are only a part of the embodiments of the present application, and are not all of the embodiments. All other embodiments obtained based on the embodiments of the present application without the need for creative efforts by those skilled in the art are within the scope of protection of the present application.

[0036] Unless otherwise defined, all scientific and technical terms used in this application have the same meaning as commonly understood by those skilled in the art of this application. In this application, the terms used in the specification of the application are used only to describe specific embodiments and are not intended to limit the application. The terms "comprise", "have" and any variations thereof in the specification and claims of this application and the above drawings are intended to cover non-exclusive "comprise". The terms "first", "second", etc. in the specification and claims of this application or the above drawings are intended to distinguish different objects and are not intended to describe a specific order or a main-subordinate relationship.

[0037] The term "embodiment" as used herein means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearances of the phrase in various locations in the specification are not necessarily all referring to the same embodiment, nor are they mutually exclusive of other embodiments as separate or alternative embodiments.

[0038] In the description of this application, it should be explained that unless otherwise specified and limited, the terms "attached", "connected", "connected" and "attached" should be understood in a broad sense, for example, they may be fixedly connected, detachably connected, or integrally connected, may be directly connected, may be indirectly connected via an intermediate medium, or may communicate with the insides of two elements. Those skilled in the art can understand the specific meaning of the above terms in the present application according to the specific situation.

[0039] In the embodiments of the present application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components in different embodiments will be omitted. In addition, the dimensions such as thickness, length, width, etc. of each member in the embodiments of the present application shown in the drawings, and the overall dimensions such as thickness, length, width, etc. of the integrated device are merely illustrative and do not limit the present application.

[0040] In this application, "plurality" refers to two or more (including two).

[0041] 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, or a magnesium ion battery, etc., but is not limited thereto in the embodiments of the present application. The battery cell may be cylindrical, flat, rectangular, or other shapes, etc., but is not limited thereto in the embodiments of the present application. According to the packaging form, the battery cell is generally divided into three types, namely, a prismatic battery cell, a rectangular battery cell, and a soft pouch battery cell, but is not limited thereto in the embodiments of the present application.

[0042] The battery referred to in the 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. The battery generally includes a housing for packaging one or more battery cells. The housing can prevent liquid or other foreign matter from affecting the charging or discharging of the battery cells.

[0043] The battery cell includes an electrode assembly and an electrolyte, and the electrode assembly is composed of a positive electrode plate, a negative electrode plate, and a separator. The battery cell mainly operates by the movement of metal ions between the positive electrode plate and the negative electrode plate. The positive electrode plate includes a positive electrode collector and a positive electrode active material layer, and the positive electrode active material layer is coated on the surface of the positive electrode collector, and the positive electrode collector without the positive electrode active material layer protrudes from the positive electrode collector coated with the positive electrode active material layer, and the positive electrode collector without the positive electrode active material layer is called a positive electrode tab. Taking a lithium ion battery as an example, the material of the positive electrode collector may be aluminum, and the positive electrode active material may be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganate, etc. The negative electrode plate includes a negative electrode collector and a negative electrode active material layer, the negative electrode active material layer is coated on the surface of the negative electrode collector, the negative electrode collector not coated with the negative electrode active material layer protrudes from the negative electrode collector coated with the negative electrode active material layer, and the negative electrode collector not coated with the negative electrode active material layer is a negative electrode tab. The material of the negative electrode collector may be copper, and the negative electrode active material may be carbon or silicon, etc. The number of positive electrode tabs is stacked in a plurality, and the number of negative electrode tabs is stacked in a plurality, so that melting does not occur even when a large current is passed. The material of the separator may be PP (polypropylene) or PE (polyethylene), etc. In addition, the electrode assembly may be a wound type structure or a stacked type structure, and the embodiment of the present application is not limited thereto.

[0044] In a battery cell, the tab is generally welded to a conductive member (current collecting part, electrode terminal, etc.) to output the electrical energy of the battery cell.

[0045] The inventors discovered that in order to ensure good robustness after welding the tab and the conductive member, the fusion portion formed by welding the tab and the conductive member needs to be sufficiently deep. However, the deeper the fusion portion, the higher the heat the tab receives during welding, and since the tab is formed by stacking multiple sheets, the higher the temperature the tab receives, the more likely it is to expand and deform, which causes cracks to form at the position where the tab and the fusion portion are connected, making it easier for the conductive member and the tab to fall off after welding the tab and the conductive member, which affects the service life of the battery cell.

[0046] In view of this, an embodiment of the present application provides a tab welding structure, in which a tab and a conductive member are welded to form a fusion region, the fusion region including a first fusion portion and a second fusion portion separated from each other, the first fusion portion extending from the tab into the conductive member along a first direction, the second fusion portion being separated from the first fusion portion, the second fusion portion being located on a side of the first fusion portion, and the second fusion portion being configured to connect the first fusion portion and the tab.

[0047] In such a tab welding structure, the second fusion portion serves to connect the first fusion portion and the tab, which is equivalent to the first fusion portion and the tab being fused via the second fusion portion, reducing the risk of cracks caused by the tab being directly connected to the first fusion portion, improving the robustness of the tab and the conductive member after welding, and improving the service life of the battery cell. In addition, since the fusion region formed by welding the tab and the conductive member includes the first fusion portion and the second fusion portion, the overcurrent area between the conductive member and the tab is increased.

[0048] The technical solutions described in the embodiments of the present application are applicable to batteries and power-consuming devices that use batteries.

[0049] The power consumption devices may be vehicles, mobile phones, portable devices, notebook computers, steamships, spacecraft, electric toys and power tools, etc. The vehicles may be fuel oil vehicles, gas vehicles or new energy vehicles, the new energy vehicles may be pure electric vehicles, hybrid vehicles or range extender vehicles, etc., the spacecraft include airplanes, rockets, space shuttles and spaceships, etc., the electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric steamship toys, electric airplane toys, etc., and the electric tools include metal cutting electric tools, polishing electric tools, assembly electric tools and railway electric tools, such as electric drills, electric grinders, electric wrenches, electric drivers, electric hammers, hammer drills, concrete vibrators, electric planes, etc. The embodiments of the present application are not particularly limited to the above power consumption devices.

[0050] In the following embodiment, for ease of explanation, the power consuming device is a vehicle.

[0051] 1 is a structural schematic diagram of a vehicle 1000 according to some embodiments of the present application, in which a battery 100 is installed inside the vehicle 1000, and the battery 100 may be installed at the bottom, head or tail of the vehicle 1000. The battery 100 can be used to power the vehicle 1000, for example, the battery 100 can be an operating power source for the vehicle 1000.

[0052] The vehicle 1000 may further include a controller 200 and a motor 300, where the controller 200 is configured to control the battery 100 to power the motor 300 for use in, for example, starting, navigating, and running operating power needs of the vehicle 1000.

[0053] In some embodiments of the present application, the battery 100 can be used not only as an operating power source for the vehicle 1000, but also as a driving power source for the vehicle 1000, providing driving power to the vehicle 1000 in place of, or in place of, fuel oil or natural gas.

[0054] Referring to FIG. 2, FIG. 2 is a structural schematic diagram of a battery 100 according to some embodiments of the present application, the battery 100 includes a housing 10 and a battery cell 20, and the housing 10 is for housing the battery cell 20.

[0055] Here, the housing 10 is a member that houses the battery cells 20, and the housing 10 provides a housing space for the battery cells 20, and the housing 10 may adopt various structures. In some embodiments, the housing 10 may include a first portion 11 and a second portion 12, and the first portion 11 and the second portion 12 are covered with each other to define a housing space for housing the battery cells 20. The first portion 11 and the second portion 12 may have various shapes, for example, a rectangular parallelepiped, a cylindrical body, etc. The first portion 11 may be a hollow structure with one side open, and the second portion 12 may be a hollow structure with one side open, and the open side of the second portion 12 is covered with the open side of the first portion 11 to form the housing 10 having the housing space. The first part 11 may have a hollow structure with one side open, and the second part 12 may have a plate-like structure, and the second part 12 may be fitted over the open side of the first part 11 to form a housing 10 having an accommodation 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.

[0056] In the battery 100, the battery cell 20 may be one or more. If there are more than one battery cell 20, the battery cells 20 may be connected in series, parallel, or series-parallel, and the series-parallel connection means that the battery cells 20 are connected in series or parallel. The battery modules may first be connected in series, parallel, or series-parallel to form a battery module, and then the battery modules may be connected in series, parallel, or series-parallel to form a whole and housed in the housing 10. All the battery cells 20 may be directly connected in series, parallel, or series-parallel, and then the whole consisting of all the battery cells 20 may be housed in the housing 10.

[0057] In some embodiments, the battery 100 may further include a bus bar member, and the bus bar member may provide electrical connection between the multiple battery cells 20, thereby enabling series connection, parallel connection, or series-parallel connection of the multiple battery cells 20. The bus bar member may be a metal conductor, such as copper, iron, aluminum, stainless steel, or an aluminum alloy.

[0058] Referring to FIG. 3, FIG. 3 is an exploded view of a battery cell 20 according to some embodiments of the present application, where the battery cell 20 includes a case 21, an electrode assembly 22, an end cap 23, and a conductive member 251.

[0059] The case 21 is a member for housing the electrode assembly 22, and may be a hollow structure with an opening at one end. The case 21 may have various shapes, such as a cylinder or a rectangle. The material of the case 21 may be various, such as copper, iron, aluminum, steel, or an aluminum alloy.

[0060] There may be one or more electrode assemblies 22 in the case 21. For example, as shown in Fig. 3, there are multiple electrode assemblies 22, and the multiple electrode assemblies 22 are arranged in a stack.

[0061] The electrode assembly 22 is a member in which an electrochemical reaction occurs in the battery cell 20. The electrode assembly 22 may include a positive electrode plate, a negative electrode plate, and a separator. The electrode assembly 22 may have a wound structure formed by winding a positive electrode plate, a separator, and a negative electrode plate, or may have a stacked structure formed by stacking a positive electrode plate, a separator, and a negative electrode plate.

[0062] The positive electrode plate may include a positive electrode current collector and a positive electrode active material layer coated on both opposing sides of the positive electrode current collector. The negative electrode plate may include a negative electrode current collector and a negative electrode active material layer coated on both opposing sides of the negative electrode current collector. The electrode assembly 22 has a tab 252, which is divided into a positive electrode tab 252 and a negative electrode tab 252. The positive electrode tab 252 may be a portion of the positive electrode plate where the positive electrode active material layer is not coated, and the negative electrode tab 252 may be a portion of the negative electrode plate where the negative electrode active material layer is not coated.

[0063] The end cap 23 is a member that is placed over the opening of the case 21 to isolate the internal environment of the battery cell 20 from the external environment. The end cap 23 is placed over the opening of the case 21, and the end 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 may be adapted to the shape of the case 21. For example, the case 21 has a rectangular parallelepiped structure, and the end cap 23 has a rectangular plate-like structure that fits the case 21. Alternatively, for example, the case 21 has a cylindrical structure, and the end cap 23 has a circular plate-like structure that fits the case 21. The material of the end cap 23 may be various, for example, copper, iron, aluminum, steel, aluminum alloy, etc., and the material of the end cap 23 may be the same as or different from the material of the case 21.

[0064] The conductive member 251 is a conductive member welded to the tab 252, and the conductive member 251 and the tab 252 are welded to form a tab welded structure 25 (not shown in FIG. 3). The conductive member 251 may be an electrode terminal 231 installed on the end cap 23, and the conductive member 251 may be a current collecting part connected between the tab 252 and the electrode terminal 231. When the conductive member 251 is the electrode terminal 231, the tab 252 and the electrode terminal 231 are directly connected. When the conductive member 251 is a current collecting part, the tab 252 and the electrode terminal 231 are indirectly connected via the current collecting part. The conductive member 251 may be a metal conductor, for example, copper, iron, aluminum, steel, aluminum alloy, etc.

[0065] In some embodiments, the battery cell 20 may further include a pressure relief mechanism 24, which is a member that releases pressure inside the battery cell 20. The pressure relief mechanism 24 is installed on the end cap 23, and when the pressure or temperature inside the battery cell 20 reaches a threshold value, the pressure relief mechanism 24 releases the pressure inside the battery cell 20. The pressure relief mechanism 24 may be a member such as an explosion-proof valve, an explosion-proof sheet, or a pressure relief valve.

[0066] In some embodiments, the battery cell 20 may further include an insulating member, which is a member that separates the end cap 23 and the electrode assembly 22. The insulating member is installed on the side of the end cap 23 facing the electrode assembly 22, and the insulating member realizes insulation and isolation between the end cap 23 and the electrode assembly 22. The insulating member is an insulating material, and may be made of materials such as plastic, rubber, etc.

[0067] 4, which is a cross-sectional view of a tab welding structure 25 according to some embodiments of the present application, the embodiments of the present application provide a tab welding structure 25, which includes a conductive member 251 and a tab 252 formed by stacking multiple layers of sheets along a first direction Z. The conductive member 251 is welded to the tab 252 to form a fusion region 253.

[0068] Here, the fused region 253 includes a first fused portion 2531 and a second fused portion 2532. The first fused portion 2531 extends from the tab 252 into the conductive member 251 along the first direction Z. The second fused portion 2532 is partitioned from the first fused portion 2531, is located on a side of the first fused portion 2531, and is configured to connect the first fused portion 2531 and the tab 252.

[0069] The tab 252 has a multi-layer structure, and is formed by stacking multiple layers of sheets along a first direction Z, where the first direction Z is the thickness direction of the sheets. For example, in the case where the electrode assembly 22 (shown in FIG. 3) has a wound structure, the electrode plates (positive electrode plate, negative electrode plate) form multiple sheet-like subtabs spaced apart from one another on one side in the width direction before being wound, and after the electrode plates are wound, the multiple subtabs are stacked to form the tab 252. The subtabs may be a sheet forming the tab 252. Before the tab 252 is welded to the conductive member 251, the multiple layers of sheets in the tab 252 may be welded by welding.

[0070] The conductive member 251 is a member that is welded to the tab 252 to form a fused region 253. In the battery cell 20, the conductive member 251 may be an electrode terminal 231, a current collecting part, or the like.

[0071] The fusion region 253 is a portion 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 portion 2532 is a portion where the fusion region 253 connects the tab 252 and the conductive member 251. Department 253 2 The fusion region 253 is the 1 Fusion section 253 1 and the tab 252. The first fusion portion 2531 and the second fusion portion 2532 are partitioned from each other, and a partition surface is formed at the position where the first fusion portion 2531 and the second fusion portion 2532 are connected, and the first fusion portion 2531 and the second fusion portion 2532 are formed by two welding operations. The first fusion portion 2531 and the second fusion portion 2532 have various partition forms. For example, the first fusion portion 2531 and the second fusion portion 2532 may be partitioned from each other by having different colors, or the first fusion portion 2531 and the second fusion portion 2532 may be partitioned from each other by having different surface roughness.

[0072] The second fusion portion 2532 is located on the side of the first fusion portion 2531, and serves to connect the first fusion portion 2531 and the tab 252, which corresponds to the first fusion portion 2531 and the tab 252 being fused via the second fusion portion 2532, reducing the risk of cracks at the welding position of the tab 252 due to the tab 252 being directly connected to the first fusion portion 2531, improving the robustness after welding between the tab 252 and the conductive member 251, and improving the service life of the battery cell 20. In addition, since the fusion region 253 formed by welding the tab 252 and the conductive member 251 includes the first fusion portion 2531 and the second fusion portion 2532, the overcurrent area between the conductive member 251 and the tab 252 is increased.

[0073] In some embodiments, with continued reference to FIG. 4, the blend depth of second blend portion 2532 in first direction Z is less than the blend depth of first blend portion 2531 .

[0074] The fusion depth of first fusion portion 2531 is the size of first fusion portion 2531 in first direction Z, and the fusion depth of second fusion portion 2532 is the size of second fusion portion 2532 in first direction Z. Since the fusion depth of second fusion portion 2532 is smaller than the fusion depth of first fusion portion 2531, the lower end of first fusion portion 2531 is located at a position deeper than the lower end of second fusion portion 2532.

[0075] Since the fusion depth of second fusion portion 2532 is smaller than the fusion depth of first fusion portion 2531, the welding temperature when welding tab 252 and conductive member 251 to form second fusion portion 2532 is smaller than the welding temperature when welding tab 252 and conductive member 251 to form first fusion portion 2531. Therefore, in the process of forming second fusion portion 2532, tab 252 is less affected by heat and is less susceptible to thermal expansion.

[0076] The size of the first fusion portion 2531 in the first direction Z is relatively long and the depth of the fusion region 253 is large, ensuring robustness after welding between the tab 252 and the conductive member 251. The size of the second fusion portion 2532 in the first direction Z is relatively short and the second fusion portion 2532 serves to provide a good connection between the first fusion portion 2531 and the tab 252 and reduces the risk of cracks at the welding position of the tab 252.

[0077] In some embodiments, with continued reference to FIG. 4, in the first direction Z, the second blend portion 2532 does not extend beyond the tab 252 along the direction in which the tab 252 faces the conductive member 251 .

[0078] As shown in Figure 4, for example, in the case where tab 252 is located on the upper side of conductive member 251, second fusion portion 2532 does not protrude from tab 252 along the direction in which tab 252 approaches conductive member 251, i.e., the lower end of second fusion portion 2532 is located inside tab 252, so that the fusion depth of second fusion portion 2532 in first direction Z does not become too large.

[0079] The greater the fusion depth of second fusion portion 2532, the greater the thermal effect that tab 252 receives in the process of welding tab 252 and conductive member 251 to form second fusion portion 2532, making it more susceptible to expansion cracks.

[0080] On the other hand, in this embodiment, since the second fusion portion 2532 does not protrude from the tab 252 in the direction toward the conductive member 251, the second fusion portion 2532 does not extend into the interior of the conductive member 251, thereby reducing the risk of cracks occurring between the second fusion portion 2532 and the tab 252 due to the second fusion portion 2532 being too deep.

[0081] In some embodiments, the welding temperature at which the conductive member 251 and the tab 252 are welded to form the second fusion portion 2532 is lower than the welding temperature at which the conductive member 251 and the tab 252 are welded to form the first fusion portion 2531.

[0082] In the process of welding the 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 by making the welding power for forming the second fusion portion 2532 lower than the welding power for forming the first fusion portion 2531. Taking the example of laser welding the tab 252 and the conductive member 251 together, the welding power for laser welding the tab 252 and the conductive member 251 together the first time to form the first fusion portion 2531 is set as the first welding power, and the welding power for laser welding the tab 252 and the conductive member 251 together the second time to form the second fusion portion 2532 is set as the second welding power, and the second welding power is lower than the first welding power.

[0083] 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, and therefore the depth of the first fusion portion 2531 is greater than the depth of the second fusion portion 2532, and the depth of the fusion region 253 is large, thereby ensuring robustness after welding between the tab 252 and the conductive member 251. Since the welding temperature for forming the second fusion portion 2532 is relatively low, the tab 252 is less likely to expand and deform in the process of forming the second fusion portion 2532, thereby reducing the risk of cracks occurring at the connection position between the second fusion portion 2532 and the tab 252.

[0084] In some embodiments, referring to FIG. 5, FIG. 5 is a top view of the tab welding structure 25 shown in FIG. 4, where the second fusion portion 2532 is located on the outer circumferential side of the first fusion portion 2531, and the second fusion portion 2532 extends and distributes along the circumferential direction of the first fusion portion 2531.

[0085] The second fusion portion 2532 is disposed on the outer circumferential 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 portion 2532 extends and distributes along the circumferential direction of the first fusion portion 2531, and the second fusion portion 2532 may be a full surrounding structure extending along the circumferential direction of the first fusion portion 2531 and having a continuous end, or a semi-encircling structure extending along the circumferential direction of the first fusion portion 2531 and having a distance between its end.

[0086] In this embodiment, the second fusion portion 2532 is located on the outer circumferential side of the first fusion portion 2531 and extends and distributes along the circumferential direction of the first fusion portion 2531, so that the tab 252 is less susceptible to cracking in multiple directions of the first fusion portion 2531, thereby improving the robustness after welding between the tab 252 and the conductive member 251.

[0087] In some embodiments, as shown in Figures 4 and 5, in the first direction Z, the tab 252 is arranged in a stacked manner with the conductive member 251, and the first fusion portion 2531 extends locally through the tab 252 into the conductive member 251.

[0088] For example, in the case where tab 252 is located on the upper side of conductive member 251, first fusion portion 2531 penetrates tab 252 from top to bottom, and the bottom of first fusion portion 2531 extends into the interior of conductive member 251, thereby connecting first fusion portion 2531 and conductive member 251.

[0089] In this embodiment, the tab 252 is disposed in a stacked manner with the conductive member 251 in the first direction Z, and the first fusion portion 2531 penetrates the tab 252 and extends locally into the conductive member 251, thereby improving the robustness after welding between the tab 252 and the conductive member 251. The tab 252 and the conductive member 251 may also be welded by a penetration welding method, thereby forming the first fusion portion 2531 and the second fusion portion 2532, and reducing the difficulty of welding.

[0090] In some embodiments, referring to Figures 6 and 7, Figure 6 is a cross-sectional view of a welded structure of a tab 252 according to some other embodiments of the present application, and Figure 7 is a top view of the tab welded structure 25 shown in Figure 6, in which a second welded portion 2532 is disposed on at least one side of a first welded portion 2531 in a second direction X, where the second direction X is perpendicular to the first direction Z.

[0091] The second direction X may be perpendicular to the first direction Z, the first direction Z may coincide with the fusion depth direction of the first fusion portion 2531, and the second direction X may coincide with the width direction of the first fusion portion 2531. The second fusion portion 2532 may be provided only on the side of the first fusion portion 2531 that is closer to the tab 252, or may be provided on both the side of the first fusion portion 2531 that is closer to the tab 252 and the side of the first fusion portion 2531 that is farther from the tab 252. For example, in FIG. 6 and FIG. 7, the second fusion portion 2532 is provided on the side of the first fusion portion 2531 that is closer to the tab 252 in the second direction, and the second fusion portion 2532 is not provided on the side of the first fusion portion 2531 that is farther from the tab 252.

[0092] In this embodiment, a second fusion portion 2532 is provided on at least one side of the first fusion portion 2531 in the second direction X, and the second fusion portion 2532 serves to connect the first fusion portion 2531 and the tab 252 on one or both sides of the first fusion portion 2531 in the second direction X, thereby simplifying the welding process and improving the welding efficiency.

[0093] 6 and 7, the conductive member 251 includes a body portion 2511 and a protrusion 2512. The body portion 2511 has an abutment surface 2511a. The protrusion 2512 protrudes from the abutment surface 2511a. The tab 252 abuts against the abutment surface 2511a along a first direction Z, and a weld bead 2513 is formed between the tab 252 and the protrusion 2512 in a second direction X, and a fused region 253 is formed in the weld bead 2513, and the second direction X is perpendicular to the first direction Z.

[0094] The contact surface 2511a is a surface of the main body 2511 that contacts the tab 252, and illustratively, the contact surface 2511a is a flat surface. The second direction X is perpendicular to the first direction Z, and the second direction X may coincide with the width direction of the first fusion portion 2531.

[0095] 6 , the second fusion portion 2532 is located on a side of the first fusion portion 2531 closer to the tab 252 in the second direction X. In the first direction Z, the fusion depth of the second fusion portion 2532 is smaller than the fusion depth of the first fusion portion 2531, and the lower end of the second fusion portion 2532 is located inside the tab 252, and the lower end of the first fusion portion 2531 extends inside the conductive member 251.

[0096] In this embodiment, the tab 252 abuts against the abutment surface 2511a of the main body 2511, a weld bead 2513 is formed between the tab 252 and the protruding portion 2512, and the fusion region 253 is formed in the weld bead 2513, thereby realizing seam welding between the tab 252 and the conductive member 251. Since the fusion region 253 is formed in the weld bead 2513 between the weld tab 252 and the protruding portion 2512, the tab 252 is less affected by heat during welding, thereby reducing the risk of cracks occurring at the connection position between the second fusion portion 2532 and the tab 252.

[0097] An embodiment of the present application provides a battery cell 20, including a tab weld structure 25 according to any one of the embodiments described above.

[0098] In some embodiments, referring to FIG. 8 and FIG. 9 , FIG. 8 is a welding structure diagram of a tab 252 and an electrode terminal 231 of a battery cell 20 according to some embodiments of the present application, and FIG. 9 is a welding structure diagram of a tab 252 and an electrode terminal 231 of a battery cell 20 according to still another some embodiments of the present application, 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.

[0099] 8, the tab 252 and the electrode terminal 231 are welded to form a fusion region 253. In FIG 9, the tab 252 and the electrode terminal 231 are welded to form a fusion region 253. In FIG 8, the tab 252 and the electrode terminal 231 are welded to form a fusion region 253.

[0100] As shown in FIGS. 8 and 9, in an embodiment in which the battery cell 20 includes multiple electrode assemblies 22 (as shown in FIG. 3), the tabs 252 (e.g., positive very The tab 252) is welded to the electrode terminal 231, and the tab 252 (e.g., negative electrode The tab 252 is welded to the electrode terminal 231 .

[0101] In some other embodiments, the battery cell 20 includes an electrode terminal 231 and a current collecting part, the current collecting part is for connecting the electrode terminal 231 and the tab 252 to realize an electrical connection between the electrode terminal 231 and the tab 252, and the current collecting part is a conductive member 251.

[0102] An embodiment of the present application provides a battery 100, which includes a housing 10 and a battery cell 20 according to any one of the embodiments described above. The housing 10 is for housing the battery cell 20.

[0103] An embodiment of the present application provides a power consuming device including a battery 100 according to any one of the above embodiments.

[0104] The power consuming device may be any one of the devices described above that uses battery 100.

[0105] An embodiment of the present application provides a method for welding the tab 252. Referring to FIG. 10, FIG. 10 is a flow chart of a method for welding the tab 252 according to some embodiments of the present application, the method includes:

[0106] Providing an electrode assembly 22 having a tab 252 formed by stacking multiple layers of sheets along a first direction Z (S100);

[0107] S200 providing a conductive member 251;

[0108] and welding the tab 252 and the conductive member 251 to form a fused region 253 S300.

[0109] Here, the fused region 253 includes a first fused portion 2531 and a second fused portion 2532. The first fused portion 2531 extends from the tab 252 into the conductive member 251 along the first direction Z. The second fused portion 2532 is partitioned from the first fused portion 2531, is located on a side of the first fused portion 2531, and is configured to connect the first fused portion 2531 and the tab 252.

[0110] This corresponds to the first fusion portion 2531 and the tab 252 being fused via the second fusion portion 2532 after the tab 252 and the conductive member 251 are welded by the above method, and reduces the risk of cracks at the welding position of the tab 252 due to the tab 252 being directly connected to the first fusion portion 2531, improves the robustness after welding of the tab 252 and the conductive member 251, and increases the service life of the battery cell 20. In addition, since the fusion region 253 formed by welding the tab 252 and the conductive member 251 includes the first fusion portion 2531 and the second fusion portion 2532, the overcurrent area between the conductive member 251 and the tab 252 is increased.

[0111] In the above method, the order of steps S100 and S200 is not limited. Step S100 may be performed first and then step S200, or step S200 may be performed first and then step S100.

[0112] In some embodiments, referring to FIG. 11, FIG. 11 is a flow chart of a method for welding the tab 252 according to still another embodiment of the present application, in which step S300 includes:

[0113] A step S310 of primarily welding the tab 252 and the conductive member 251 to form a first fusion portion 2531;

[0114] The second welding step S320 is for forming a second fusion portion 2532 by secondarily welding the tab 252 and the conductive member 251 together.

[0115] Here, the welding temperature of the secondary welding is lower than the welding temperature of the primary welding.

[0116] In the embodiment of the present application, the order of steps S310 and S320 is not limited. Step S310 may be performed first, and then step S320 may be performed. For example, the tab 252 and the conductive member 251 may be primarily welded to form a first fusion portion 2531, and then the edge of the first fusion portion 2531 may be secondary welded to form a second fusion portion 2532 connecting the first fusion portion 2531 and the tab 252. Step S320 may be performed first, and then step S310 may be performed. For example, the tab 252 and the conductive member 251 may be secondary welded to form a second fusion portion 2532, and then the edge of the second fusion portion 2532 may be primarily welded to form the first fusion portion 2531 connecting the second fusion portion 2532 and the conductive member 251.

[0117] The welding temperature of the secondary welding is lower than that of the primary welding, which means that the welding power of the secondary welding is lower than that of the primary welding. electric power Taking the case of laser welding the tab 252 and the conductive member 251 as an example, the welding power for forming the second fused portion 2532 by the secondary laser welding is smaller than the welding power for forming the first fused portion 2531 by the primary laser welding.

[0118] In this embodiment, the welding temperature for the primary 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 robustness is ensured after welding of the tab 252 and the conductive member 251. The welding temperature for the secondary welding of the tab 252 and the conductive member 251 is relatively low, so that the tab 252 is less likely to expand and deform in the process of forming the second fusion portion 2532, and the risk of cracks occurring at the connection position between the second fusion portion 2532 and the tab 252 is reduced.

[0119] In some embodiments, the secondary welding of the conductive member 251 and the tab 252 includes multiple ring welding the tab 252 and the conductive member 251 circumferentially from the inside to the outside to form a second fusion portion 2532.

[0120] Referring to FIG. 12, FIG. 12 is a welding trajectory diagram of the conductive member 251 and the tab 252 according to some embodiments of the present application. When the conductive member 251 and the tab 252 are secondarily welded, they may be welded from the inside to the outside along the secondary welding trajectory A, and when the conductive member 251 and the tab 252 are primarily welded, they may be welded in a spiral manner along the primary welding trajectory B.

[0121] By multiple ring welding the tab 252 and the conductive member 251 along the circumferential direction, a second fusion portion 2532 extending and distributed along the circumferential direction of the first fusion portion 2531 is formed, making the tab 252 less susceptible to cracking in multiple directions of the first fusion portion 2531, and improving the robustness after welding between the tab 252 and the conductive member 251.

[0122] In some embodiments, the welding temperature of each ring is stepped down from the inside to the outside.

[0123] In the process of forming the second fusion portion 2532 by welding the tab 252 and the conductive member 251 together in the circumferential direction from the inside to the outside in multiple rings, the welding temperature of each ring gradually decreases from the inside to the outside, so that the fusion depth of the second fusion portion decreases in a stepped manner from the inside to the outside. As a result, the thermal effect on the tab 252 due to the welding of each ring from the inside to the outside gradually decreases, further reducing the risk of cracks occurring at the connection position between the second fusion portion 2532 and the tab 252.

[0124] An embodiment of the present application further provides a welding apparatus 2000 for the tab 252, and referring to FIG. 13, FIG. 13 is a schematic block diagram of a welding apparatus 2000 for the tab 252 according to some embodiments of the present application, the welding apparatus 2000 including a first providing device 2100, a second providing device 2200, and a welding apparatus 2300.

[0125] The first providing device 2100 is for providing an electrode assembly 22 having a tab 252 formed by stacking multiple layers of sheets along a first direction Z. 2 Provision of equipment 2 223.00 is for providing a conductive member 251. Welding apparatus 2300 is for welding tab 252 and conductive member 251 such that tab 252 and conductive member 251 form fused region 253.

[0126] Here, the fused region 253 includes a first fused portion 2531 and a second fused portion 2532. The first fused portion 2531 extends from the tab 252 into the conductive member 251 along the first direction Z. The second fused portion 2532 is partitioned from the first fused portion 2531, is located on a side of the first fused portion 2531, and is configured to connect the first fused portion 2531 and the tab 252.

[0127] It should be noted that, where there is no conflict, the embodiments and features in the embodiments in the present application can be combined with each other.

[0128] The above examples are only intended to explain the technical solution of the present application, and are not intended to limit the present application, and those skilled in the art may make various modifications and variations to the present application. All modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application shall be included within the protection scope of the present application. [Explanation of symbols]

[0129] 10-housing, 11-first part, 12-second part, 20-battery cell, 21-case, 22-electrode assembly, 23-end cap, 231-electrode terminal, 24-pressure relief mechanism, 25-tab welding structure, 251-conductive member, 2511-main body, 2511a-contact surface, 2512-protrusion, 2513-weld bead, 252-tab, 253-fusion region, 2531-first fusion portion, 2532-second fusion portion, 100-battery, 200-controller, 300-motor, 1000-vehicle, 2000-welding equipment, 2100-first providing device, 2200-second providing device, 2300-welding device, A-secondary welding trajectory, B-primary welding trajectory, Z-first direction, X-second direction.

Claims

1. A tab welded structure, A tab formed by laminating a plurality of sheets along a first direction; a conductive member welded to the tab to form a fused region; wherein the fusion region is a first blend portion extending from the tab into the conductive member along the first direction; a second fusion portion spaced apart from the first fusion portion, located on a side of the first fusion portion, and configured to connect the first fusion portion and the tab; A tab welding structure, wherein a welding temperature at which the conductive member and the tab are welded to form a second fusion portion is lower than a welding temperature at which the conductive member and the tab are welded to form a first fusion portion.

2. The tab weld structure of claim 1 , wherein a fusion depth of the second fusion portion is less than a fusion depth of the first fusion portion in the first direction.

3. The tab welding structure according to claim 1 or 2, wherein in the first direction, the second fusion portion does not protrude from the tab along a direction in which the tab faces the conductive member.

4. 4. The tab welding structure according to claim 1, wherein the second fusion portion is disposed on an outer circumferential side of the first fusion portion, and the second fusion portion is distributed extending along a circumferential direction of the first fusion portion.

5. 5. The tab welding structure according to claim 1, wherein in the first direction, the tab is disposed in a stacked manner with the conductive member, and the first fusion portion extends locally through the tab into the conductive member.

6. The second blending portion is provided on at least one side of the first blending portion in the second direction, The tab welding structure according to claim 1 , wherein the second direction is perpendicular to the first direction.

7. The conductive member is A main body having an abutment surface; a protrusion protruding from the contact surface, 7. The tab welding structure of claim 1, wherein the tab abuts against the abutment surface along the first direction and a weld bead is formed between the tab and the protrusion in a second direction, the fusion region is formed in the weld bead, and the second direction is perpendicular to the first direction.

8. A battery cell comprising the tab welding structure of any one of claims 1 to 7.

9. The battery cell according to claim 8 , wherein the battery cell includes an electrode terminal electrically connected to the tab, the electrode terminal being the conductive member.

10. The battery cell includes: An electrode terminal; The battery cell according to claim 8 , further comprising a current collecting part which is the conductive member for connecting the electrode terminal and the tab to realize an electrical connection between the electrode terminal and the tab.

11. A battery, A battery cell according to any one of claims 8 to 10; and a housing for housing the battery cell.

12. 12. A power consuming device comprising the battery of claim 11.

13. A method of welding a tab, comprising the steps of: providing an electrode assembly having a tab formed by stacking a plurality of layers of sheets along a first direction; Providing a conductive member; welding the tab and the conductive member to form a fused region; wherein the fusion region is a first blend portion extending from the tab into the conductive member along the first direction; a second fusion portion spaced apart from the first fusion portion, located on a side of the first fusion portion, and configured to connect the first fusion portion and the tab; said welding said tab and said conductive member to form a fused region comprises: primarily welding the tab and the conductive member to form the first fusion portion; and secondarily welding the tab and the conductive member to form the second fused portion. wherein the welding temperature of the secondary welding is lower than the welding temperature of the primary welding.

14. The secondary welding of the tab and the conductive member includes: The method for welding a tab according to claim 13, further comprising: performing multiple ring welding of the tab and the conductive member from inside to outside along a circumferential direction to form the second fusion portion.

15. 15. The method of claim 14, wherein the welding temperature of each ring decreases stepwise from the inside to the outside.

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