Battery, battery assembly and electric equipment

Abstract

The invention provides a battery, a battery assembly and electric equipment, the battery comprises a tab group, a polarity piece and a welding part, and the tab group comprises a plurality of tabs arranged in a stacked manner; in the thickness direction of the tab group, one side, deviating from the polar piece, of the tab group comprises a first side surface and at least one first welding mark, and the first welding mark is used for fixedly connecting a plurality of tabs; the first welding mark sinks towards the polar piece relative to the first side surface and comprises a bottom surface which is located at one end, close to the polar piece, of the first welding mark; the orthographic projection of the welding part is located in the orthographic projection of the bottom surface in the thickness direction of the tab group, and / or the orthographic projection of the welding part completely coincides with the orthographic projection of the bottom surface, and the welding part is fixedly connected with the tab group and the polar piece. According to the battery disclosed by the invention, the welding performance of the tab group and the polar piece is relatively good.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a battery, a battery assembly, and an electrical device. Background Art

[0002] In the related art, the battery includes a shell, an electrode column and an electrode core. The electrode core includes multiple layers of positive electrode sheets, diaphragms and negative electrode sheets stacked in sequence. Each layer of positive electrode sheets is provided with a positive electrode ear. Multiple positive electrode ears are stacked in sequence and welded to form a positive electrode ear group. Each layer of negative electrode sheets is provided with a negative electrode ear. Multiple negative electrode ears are stacked in sequence and welded to form a negative electrode ear group. The positive electrode ear group is welded to the positive electrode column through an adapter plate, and the negative electrode ear group is welded to the negative electrode column or the shell through an adapter plate.

[0003] Since the adapter takes up space in the battery and reduces the volume energy density of the battery, the adapter is eliminated in related technologies, and the tab group and the negative electrode column or shell are directly welded. However, the direct welding effect is not good, and the tab is prone to breakage. Summary of the Invention

[0004] Based on this, the present application provides a battery, a battery assembly and an electrical device to address the deficiencies in the related art.

[0005] In a first aspect, the present application provides a battery, comprising:

[0006] A tab group, the tab group including a plurality of tabs stacked in layers;

[0007] Polarized parts;

[0008] Along the thickness direction of the tab group, the side of the tab group facing away from the polar member includes a first side surface and at least one first weld mark, the first weld mark is used to fix and connect at least part of the tab, the first weld mark is recessed toward the polar member relative to the first side surface, and the first weld mark includes a bottom surface, which is located at one end of the first weld mark close to the polar member;

[0009] At least one welding portion has an orthographic projection located within an orthographic projection of the bottom surface along the thickness direction of the tab group, and / or the orthographic projection of the welding portion completely overlaps with the orthographic projection of the bottom surface, and the welding portion fixedly connects the tab group and the polar member.

[0010] In a possible implementation, the bottom surface is at least one of a flat surface and a curved surface.

[0011] In one possible implementation, the bottom surface is a plane, and the area of ​​the bottom surface is greater than or equal to 0.0078 mm. 2 .

[0012] In a possible implementation, the bottom surface is circular, and the radius of the bottom surface ranges from 0.05 mm to 0.15 mm.

[0013] In a possible implementation, the geometric center line of the welding portion coincides with the geometric center point of the bottom surface.

[0014] In a possible implementation, an angle is formed between a plane where a side of the polar element facing the tab group is located and a plane where the bottom surface is located, and a value range of the angle is: [0°, 5°].

[0015] In a possible implementation, the tab group includes a second side surface arranged opposite to the polar member, the second side surface is provided with at least one second weld mark, and the second weld mark is arranged corresponding to at least part of the first weld mark.

[0016] In one possible implementation, the first weld mark further includes a side surface, the side surface includes a first end portion and a second end portion oppositely disposed along the thickness direction of the tab group, the first end portion is connected to the first side surface, and the second end portion is connected to the bottom surface, the tab group includes a second side surface oppositely disposed to the polar member, and along the thickness direction of the tab group, the distance between the first side surface and the second side surface is the thickness T of the tab group;

[0017] Along the thickness direction of the tab group, the maximum distance D between the first end portion and the second end portion and the thickness T of the tab group satisfy the following relationship: 20%T≤D≤70%T.

[0018] In a possible implementation, along the thickness direction of the tab group, the orthographic projection of the second end portion is located within the orthographic projection of the first end portion.

[0019] In a possible implementation, the side of the tab group facing away from the polar member includes a plurality of first weld marks, the plurality of first weld marks are arranged at intervals, and the minimum spacing between two adjacent first weld marks is greater than or equal to 0.05 mm.

[0020] In a possible implementation, at least two welding portions are provided in at least a portion of the first weld mark.

[0021] In a possible implementation, there are multiple first weld marks, and each first weld mark is provided with at least one welding portion.

[0022] In a possible implementation, the tab group includes at least one first tab group and at least one second tab group, and the polarities of the first tab group and the second tab group are opposite;

[0023] The polar member includes a first polar member and a second polar member, and a first welding mark is provided on a side of the first tab group facing away from the first polar member, and the welding portion fixedly connects the first tab group and the first polar member;

[0024] A first weld mark is provided on a side of the second tab group facing away from the second polarity member, and the weld portion fixedly connects the second tab group and the second polarity member.

[0025] In a second aspect, the present application provides a battery assembly comprising at least one battery provided in the first aspect and a circuit structure, wherein the battery is electrically connected to the circuit structure.

[0026] In a third aspect, the present application provides an electrical device comprising the battery provided in the first aspect above, and / or the battery assembly provided in the second aspect above.

[0027] The battery, battery assembly and electrical equipment provided in the present application, the battery includes a tab group, a polar part and a welding part, the tab group includes multiple tabs and a first weld mark, the tab group and the polar part are provided for transmitting current, the first weld mark which is recessed toward the polar part and has a bottom surface is provided for pre-fixed connection of multiple tabs to eliminate the interlayer gaps of multiple tabs in the bottom area, and the welding part is provided for fixed connection of the tab group and the polar part so that the tab group and the polar part are conductive. In this way, in the thickness direction of the tab group, since the orthographic projection of the welding part is located within the orthographic projection of the bottom surface, and / or the orthographic projection of the welding part overlaps with the orthographic projection of the bottom surface, the interlayer gaps between the tab group and the parts corresponding to the bottom surface are smaller, thereby preventing the tabs from breaking due to welding stress when the tab group and the polar part are welded to form a welding part.

[0028] In addition to the technical problems solved by the embodiments of the present application described above, the technical features that constitute the technical solutions, and the beneficial effects brought about by the technical features of these technical solutions, other technical problems that can be solved by the batteries, battery assemblies, and electrical equipment provided by the present application, other technical features included in the technical solutions, and the beneficial effects brought about by these technical features will be further described in detail in the specific implementation methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0030] Figure 1 A schematic diagram of the structure of a battery provided in an embodiment of the present application;

[0031] Figure 2 A schematic diagram of welding the tab group and the electrode column in the battery provided in an embodiment of the present application;

[0032] Figure 3 Another schematic diagram of welding the tab group and the electrode column in the battery provided in an embodiment of the present application;

[0033] Figure 4 A schematic diagram of the structure of the tab group in the battery provided in an embodiment of the present application;

[0034] Figure 5 A microscope image of a battery provided in an embodiment of the present application;

[0035] Figure 6 A microscope image of a battery of related art.

[0036] Description of reference numerals:

[0037] 10-battery; 100-electrode core; 200-electrode tab group; 210-first weld mark; 211-bottom surface; 212-side surface; 2121-first end portion; 2122-second end portion; 220-first side surface; 230-second side surface; 240-second weld mark; 200a-first electrode tab group; 200b-second electrode tab group; 300-polarity part; 400-welding portion; 500-shell. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solutions and advantages of the present application clearer, the technical solutions in the embodiments of the present application will be described in more detail below in conjunction with the drawings in the preferred embodiments of the present application. In the drawings, the same or similar reference numerals throughout represent the same or similar parts or parts with the same or similar functions. The described embodiments are part of the embodiments of the present application, not all of the embodiments. The embodiments described below with reference to the drawings are exemplary and are intended to be used to explain the present application, and should not be understood as limitations on the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application. The embodiments of the present application are described in detail below in conjunction with the drawings.

[0039] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood broadly. For example, they may refer to a fixed connection, an indirect connection via an intermediate medium, internal communication between two components, or an interaction between two components. Those skilled in the art will understand the specific meanings of these terms in this application based on specific circumstances.

[0040] In the description of this application, it should be understood that the terms "upper", "lower", "front", "back", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are orientations or positional relationships based on the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on this application.

[0041] The terms "first," "second," and "third" (if any) in the specification and claims of this application and the accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a particular order or sequence. It should be understood that the terms used in this manner are interchangeable where appropriate, such that the embodiments of the application described herein can be practiced in orders other than those illustrated or described herein.

[0042] In addition, the terms "comprises" and "having" and any variations thereof are intended to cover a non-exclusive inclusion, for example, a process, method, system, product or display that includes a series of steps or elements is not necessarily limited to those steps or elements expressly listed but may include other steps or elements not expressly listed or inherent to such process, method, product or display.

[0043] In the related art, the battery includes a shell, a pole and a pole core. The pole core includes multiple layers of positive electrode sheets, diaphragms and negative electrode sheets stacked in sequence. Each layer of positive electrode sheets is provided with a positive electrode ear. Multiple positive electrode ears are stacked in sequence and welded to form a positive electrode ear group. Each layer of negative electrode sheets is provided with a negative electrode ear. Multiple negative electrode ears are stacked in sequence and welded to form a negative electrode ear group. The positive electrode ear group is welded to the positive pole through an adapter, and the negative electrode ear group is welded to the negative pole or shell through an adapter. The adapter will take up space in the battery, thereby reducing the volume energy density of the battery. Therefore, the related art eliminates the adapter and directly welds the pole ear group and the negative pole or shell. However, the direct welding effect is not good and the pole ear is prone to breakage.

[0044] In view of the above problems, embodiments of the present application provide a battery, a battery assembly, and an electrical device. After a plurality of tabs are fixedly connected by a first weld mark to form a tab group, the tab group and the polar member are fixedly connected by a welding portion. In addition, the plurality of tabs of the tab group are first welded to form a first weld mark on the tab group. When welding to form the weld portion, a laser can be applied to the bottom surface of the first weld mark, thereby causing the orthographic projection of the weld portion in the thickness direction of the tab group to overlap with the orthographic projection of the bottom surface in the thickness direction of the tab group, and / or causing the orthographic projection of the weld portion in the thickness direction of the tab group to be within the orthographic projection of the bottom surface in the thickness direction of the tab group. Since the plurality of tabs of the tab group have been connected by the first weld mark and the gaps between adjacent tabs have been eliminated, when the tab group and the polar member are laser welded, the tabs are not easily broken due to the gaps between the plurality of tabs. As a result, the battery provided by embodiments of the present application has a high volume energy density and good welding performance between the tab group and the polar member.

[0045] It should be noted that this application does not limit the welding method used to achieve the weld portion. That is, after welding, no weld mark may appear on the bottom surface due to welding, such as brazing or other welding methods. In this case, the weld portion is located between the tab group and the polar member. When the welding method is laser welding, a weld mark caused by the laser welding will appear on the bottom surface. In this case, the weld mark covers the bottom surface, that is, the weld mark covers the first weld mark. In this case, the weld portion can appear as a weld spot, and the weld mark caused by the laser welding spot can be seen by observing the bottom surface.

[0046] Furthermore, if multiple laser welding or continuous laser welding is performed on a bottom surface, the welding part formed on the bottom surface may be in the form of multiple stacked welding points or welds. It should be noted that the welding parts formed by laser welding are all within the scope of protection of this application, and there is no specific limitation on their shape characteristics.

[0047] The specific implementation methods of the battery, battery assembly and electrical equipment provided in the embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0048] Reference Figures 1 to 5 As shown, an embodiment of the present application provides a battery 10, which includes a core 100, two tab groups 200, and two polarity members 300. The two tab groups 200 are connected to the core 100, and the electrical polarities of the two tab groups 200 are opposite. Each tab group 200 includes a plurality of tabs arranged in a stacked manner.

[0049] Along the thickness direction of the tab group 200, the side of the tab group 200 facing away from the polar member 300 has at least one first weld mark 210 for fixedly connecting the multiple tabs of the tab group 200. The tab group 200 includes a first side surface 220 and a second side surface 230. The first side surface 220 is arranged away from the polar member 300 relative to the second side surface 230. The first weld mark 210 is recessed from the first side surface 220 toward the second side surface 230. The first weld mark 210 includes a bottom surface 211. The bottom surface 211 is located at one end of the first weld mark 210 near the second side surface 230.

[0050] The tab group 200 and the polar member 300 have at least one welded portion 400 formed by welding to securely connect the tab group 200 and the polar member 300. Along the thickness direction of the tab group 200, the orthographic projection of the welded portion 400 is located within the orthographic projection of the bottom surface 211, and / or the orthographic projection of the welded portion 400 completely overlaps with the orthographic projection of the bottom surface 211. That is, when the orthographic projection of the welded portion 400 is within the orthographic projection of the bottom surface 211, or overlaps with the orthographic projection of the bottom surface 211, the welded portion 400 will not be on the side surface 212, thereby preventing the tab from fracturing due to stress when the welded portion 400 is formed.

[0051] In this embodiment, the electrode core 100 may include a stacked electrode sheet and a separator. The electrode core 100 may be a laminated or wound type. The electrode sheets include a positive electrode sheet and a negative electrode sheet, so that the electrode core 100 can store and release electrical energy through electrochemical reactions. The two tab groups 200 are used to draw positive and negative currents from the electrode core 100. That is, one of the two tab groups 200 is a positive electrode and the other is a negative electrode. Each tab group 200 includes multiple tabs, each of which is connected to a corresponding electrode sheet. The multiple tabs are fixedly connected to form a tab group 200. The tab group 200 is then fixedly connected to the polar member 300, so that the current of the electrode core 100 is transmitted to the electrical device through the tab group 200 and the polar member 300. The polar member 300 may be a pole or a shell 500.

[0052] Therefore, the number of poles can be one or two. When there is one pole, one of the two tab groups 200 is connected to the polar part 300, and the other of the two tab groups 200 is connected to the shell 500. When there are two poles, the two tab groups 200 are connected to the two poles in a one-to-one correspondence.

[0053] It should be noted that the polar part 300 can be a pole, a shell 500, or other components that can transmit electrical energy to electrical equipment. The polar part 300 that can be welded with the tab group 200 and can transmit electrical energy to the electrical equipment is within the protection scope of this application. No specific restrictions are made here. This embodiment only takes the pole as an example.

[0054] A plurality of tabs can be pre-connected by ultrasonic welding to form a tab group 200, and a first weld mark 210 is formed on one side of the tab group 200. In this way, each tab has an area corresponding to the first weld mark 210. Since the ultrasonic wave acts on the area corresponding to the bottom surface 211 of each tab, the gaps between adjacent tabs can be eliminated. In this way, when the tab group 200 and the polar part 300 are subsequently welded by laser or brazing, the welding energy can be applied to the bottom surface 211, which can prevent the generated welding part 400 from generating welding pores and prevent the tab from breaking.

[0055] It should be noted that, referring to Figure 6 As shown, if ultrasonic pre-welding is not performed on the multiple tabs, the gaps between the multiple tabs are difficult to eliminate, which leads to the presence of gas in the gaps between the multiple tabs. When the tabs and the polar parts 300 are directly welded, welding pores are easily generated and the tabs are easily broken.

[0056] Alternatively, ultrasound is used to pre-weld multiple tabs. However, ultrasonic pre-welding does not form a bottom surface 211 suitable for welding at the bottom of the first weld mark 210. At this time, laser welding is performed, and the laser acts on the first weld mark 210. Since each tab is not completely compressed except for the part corresponding to the bottom surface 211, there is still a large interlayer gap between adjacent tabs. During laser welding, the gas in the interlayer gap cannot be removed, which can easily lead to welding pores in the welding part 400. Moreover, since the tabs are made of materials such as aluminum foil, the shrinkage rate of the aluminum foil during solidification is large, and the aluminum foil is relatively fragile, which can easily lead to the tabs breaking due to stress, resulting in reduced reliability of the welding between the tab group 200 and the polar part 300, thereby reducing the safety performance and reliability of the battery 10, and posing a safety hazard.

[0057] In this embodiment, reference Figure 2 When the tab group 200 has multiple first weld marks 210 and welding parts 400, the number of welding parts 400 can be equal to the number of first weld marks 210, that is, the welding parts 400 can be arranged in a one-to-one correspondence with the first weld marks 210, and the orthographic projection of each welding part 400 along the thickness direction of the tab group 200 is located within the orthographic projection of the corresponding bottom surface 211 along the thickness direction of the tab group 200, or, the number of welding parts 400 can also be less than the number of first weld marks 210, that is, the welding parts 400 are arranged in part of the first weld marks 210, and the orthographic projection of each welding part 400 along the thickness direction of the tab group 200 is located within the orthographic projection of the corresponding bottom surface 211 along the thickness direction of the tab group 200.

[0058] Therefore, when a first weld mark 210 is provided with a welding portion 400, the orthographic projection of the welding portion 400 can be located within the orthographic projection of the bottom surface 211, or the orthographic projection of the welding portion 400 can completely coincide with the orthographic projection of the bottom surface 211. As long as the welding portion 400 does not fall at any position other than the bottom surface 211, the tab will not be broken.

[0059] In this way, since the tab group 200 is welded in advance using ultrasound, a first weld mark 210 is generated, and a bottom surface 211 is formed at the bottom of the first weld mark 210. The interlayer gap between the tab group 200 and the corresponding parts of the bottom surface 211 is small. When the tab group 200 and the polar part 300 are subsequently welded, the welding energy acts on the bottom surface 211, which can effectively prevent the welding part 400 from generating welding pores and prevent the tab from breaking due to welding stress.

[0060] It should be noted that in order to improve the welding strength between the tab group 200 and the polar member 300, two or more welding portions 400 are provided in at least one first weld mark 210, or one or more welding portions 400 are provided in each first weld mark 210, thereby preventing a single welding portion 400 from being unable to reliably securely connect the tab group 200 and the polar member 300. Therefore, when two welding portions 400 are provided in a first weld mark 210, the orthographic projection of one welding portion 400 can be located within the orthographic projection of the bottom surface 211, and the orthographic projection of the other welding portion 400 can completely overlap with the orthographic projection of the bottom surface 211.

[0061] The battery 10 of the embodiment of the present application includes a pole core 100, a tab group 200, a polar member 300 and a welding portion 400, wherein the tab group 200 includes a plurality of tabs and a first weld mark 210. The pole core 100 is provided for storing and releasing electric energy, the tab group 200 and the polar member 300 are provided for conducting current from the pole core 100, the first weld mark 210 is provided for fixing and connecting the plurality of tabs and eliminating interlayer gaps between the plurality of tabs, and the welding portion 400 is provided for fixing and connecting the tab group 200 and the polar member 300, so that the tab group 200 and the polar member 300 are conductive. Because the first weld mark 210 is recessed from the first side surface 220 toward the polar member 300, the side of the tab group 200 facing away from the polar member 300 is formed. The concave first weld mark 210 has a relatively flat bottom surface 211, which can be used to position the welding portion 400. In this way, in the thickness direction of the tab group 200, because the orthographic projection of the welding portion 400 is located within the orthographic projection of the bottom surface 211, and / or the orthographic projection of the welding portion 400 overlaps with the orthographic projection of the bottom surface 211, the interlayer gap between the tab group 200 and the bottom surface 211 is small, thereby preventing the generation of welding pores when welding the tab group 200 and the polar member 300, and preventing the tab from breaking due to welding stress. As a result, the welding performance of the tab group 200 and the polar member 300 is better.

[0062] In a possible implementation, the tab group 200 includes a second side surface 230 close to the polar member 300 . The second side surface 230 is provided with at least one second weld mark 240 . The second weld mark 240 is arranged corresponding to at least a portion of the first weld mark 210 .

[0063] That is to say, while ultrasonic welding is performed on multiple tabs to form a first weld mark 210, ultrasonic welding can also form a second weld mark 240 on the other side of the tab group 200 in the thickness direction. In this way, before laser welding is performed on the polar member 300 and the tab group 200, the second weld mark 240 can be brought into contact with the polar member 300. The second weld mark 240 can increase the friction between the tab group 200 and the polar member 300 to prevent the tab group 200 and the polar member 300 from moving relative to each other during welding.

[0064] In some embodiments, the cross section of the second weld mark 240 may be serrated to enhance the roughness of the second weld mark 240 .

[0065] In some embodiments, the second weld mark 240 can be a frosted surface. The second weld mark 240 is relatively flat to reduce the assembly gap between the polar member 300 and the tab group 200 , which is beneficial for subsequent welding of the polar member 300 and the tab group 200 .

[0066] Reference Figure 3 and Figure 5 As shown, in one possible implementation, the geometric center point of the bottom surface 211 coincides with the geometric center line of the welding portion 400 to ensure that the orthographic projection of the welding portion 400 is located within the orthographic projection of the bottom surface 211, or to ensure that the orthographic projection of the welding portion 400 coincides with the orthographic projection of the bottom surface 211.

[0067] For example, spherical welding teeth can be used to ultrasonically weld multiple tabs, and a flat end face of the spherical welding tooth can be set on the side of the tab group 200. In this way, when the welding tooth welds the tab group 200, a pit can be formed on one side of the tab group 200, and the adjacent tabs can be effectively pressed to eliminate the interlayer gaps of the tab group 200, and the bottom of the pit has a relatively flat plane, which is conducive to positioning the welding energy at the center of the bottom surface 211 to generate a welding portion 400, so that the geometric center line of the welding portion 400 coincides with the geometric center point of the bottom surface 211.

[0068] In one possible implementation, the welding portions 400 are disposed one by one in the first weld marks 210. Thus, after ultrasonic welding is performed on a plurality of tabs to form the first weld marks 210, a laser can be subsequently used to spot weld each of the first weld marks 210, thereby forming a welding portion 400 in the first weld marks 210 to securely connect the tab group 200 and the polar member 300 without causing problems such as welding pores and tab breakage.

[0069] In some embodiments, the bottom surface 211 may be at least one of a flat surface and a curved surface. For example, the bottom surface 211 may be entirely flat, or entirely curved, or the center of the bottom surface 211 may be flat, while the edges of the bottom surface 211 may be curved. In this way, the bottom surface 211 is a relatively flat surface, which facilitates welding the tab group 200 and the polar member 300 on the bottom surface 211 by laser spot welding or brazing.

[0070] In some embodiments, the bottom surface 211 is a plane, and the area of ​​the bottom surface 211 may be greater than or equal to 0.0078 mm. 2 .

[0071] It should be noted that if the area of ​​the bottom surface 211 is less than 0.0078 mm 2 , the laser or electron beam cannot be accurately positioned on the bottom surface 211, which will cause the subsequently generated welding portion 400 to be located outside the bottom surface 211, thereby easily causing the tab group 200 to break.

[0072] In this embodiment, the area of ​​the bottom surface 211 is greater than or equal to 0.0078 mm. 2 , which is conducive to positioning the laser or electron beam on the bottom surface 211, and further conducive to the welding energy acting on the tab group 200 and the polar member 300, so that the generated weld portion 400 satisfies: along the thickness direction of the tab group 200, the orthographic projection of the weld portion 400 is located within the orthographic projection of the bottom surface 211, and / or, the orthographic projection of the weld portion 400 and the orthographic projection of the bottom surface 211 completely coincide with each other.

[0073] In some embodiments, the bottom surface 211 is circular, and the radius of the bottom surface 211 is greater than or equal to 0.05 mm, and the radius of the bottom surface 211 is less than or equal to 0.15 mm. In this way, when the radius of the bottom surface 211 is greater than or equal to 0.05 mm, the area of ​​the bottom surface 211 can be ensured to be greater than or equal to 0.0078 mm. 2 When the radius of the bottom surface 211 is less than or equal to 0.15 mm, it can prevent the single first weld mark 210 from being too large, which is conducive to forming multiple dispersed first weld marks 210 on the tab group 200, so as to improve the connection performance between multiple tabs.

[0074] That is, multiple first weld marks 210 can be formed on the tab group 200, with the minimum distance between two adjacent first weld marks 210 being greater than or equal to 0.05 mm to ensure that the multiple first weld marks 210 are spaced apart. If the minimum distance is less than 0.05 mm, the tab may break during the process of forming the first weld marks 210. Each of the multiple first weld marks 210 can be provided with a welding portion 400 to improve the connection reliability between the tab group 200 and the polar member 300.

[0075] In some embodiments, the side of the polar member 300 facing the tab group 200 is located in a first reference plane, and the bottom surface 211 is located in a second reference plane. There is an angle between the first reference plane and the second reference plane, which is greater than or equal to 0° and less than or equal to 5°.

[0076] That is to say, when the bottom surface 211 is a plane, the plane of the side of the polar member 300 facing the tab group 200 is parallel to the plane of the bottom surface 211, or the two are nearly parallel, which is conducive to welding the tab group 200 and the polar member 300.

[0077] Reference Figure 4As shown, it can be understood that since the first weld mark 210 is in a pit shape, the first weld mark 210 also includes a side surface 212, and the side surface 212 can be one of an outer convex spherical surface, a conical side surface or a cylindrical side surface. The side surface 212 includes a first end 2121 and a second end 2122 arranged opposite to each other, the first end 2121 is connected to the first side surface 220, and the second end 2122 is connected to the bottom surface 211.

[0078] Along the thickness direction of the tab group 200 , the maximum distance D between the first end portion 2121 and the second end portion 2122 and the thickness T of the tab group 200 satisfy the following relationship: 20%T≤D≤70%T.

[0079] That is to say, along the thickness direction of the tab group 200, the first end of the first weld mark 210 is open, and the second end of the first weld mark 210 is connected to the bottom surface 211. The maximum distance D between the first end 2121 and the second end 2122 can be understood as the maximum depth of the first weld mark 210, and the thickness T of the tab group 200 can be understood as the distance from the first side surface 220 to the second side surface 230.

[0080] If D is less than 0.2T, the depth of the first weld mark 210 will be smaller, and the first weld mark 210 will not be able to effectively connect multiple tabs in the tab group 200. If D is greater than 0.7T, the tabs will easily break during welding and the welding efficiency will be reduced.

[0081] Therefore, in this embodiment, D is between 0.2T and 0.7T, which is beneficial to improving the welding performance of the first weld mark 210 and improving the welding efficiency of the first weld mark 210 .

[0082] In some embodiments, along the thickness direction of the tab group 200, the orthographic projection of the second end 2122 is located within the orthographic projection of the first end 2121. Such a setting is conducive to the irradiation of the laser or electron beam from the first end 2121 toward the second end face, thereby facilitating the positioning of the laser or electron beam within the bottom surface 211, thereby facilitating the welding energy to act on the bottom surface 211.

[0083] It can be seen from this that the side surface 212 is not limited to one of the convex spherical surface, conical side surface or cylindrical side surface. The first weld mark 210 that is conducive to the irradiation of laser or electron beam from the first end 2121 toward the second end 2122 is within the scope of protection of this application and is not specifically limited here.

[0084] Reference Figure 1 As shown, in some embodiments, the two tab groups 200 include a first tab group 200a and a second tab group 200b, and the first tab group 200a and the second tab group 200a have opposite electrical polarities. The polarity piece 300 includes a first polarity piece and a second polarity piece, and the first polarity piece and the second polarity piece have opposite electrical polarities.

[0085] For example, the polarity member 300 includes a first electrode and a second electrode, the first electrode and the second electrode having opposite electrical polarities. A first electrode tab group 200a has a first weld mark 210 on the side facing away from the first electrode, and the first electrode tab group 200a and the first electrode are connected by a weld 400. A second electrode tab group 200b has a first weld mark 210 on the side facing away from the second electrode, and the second electrode group 200b and the second electrode are connected by a weld 400.

[0086] The first pole lug group 200a and the first pole are both positively charged, the second pole lug group 200b and the second pole are both negatively charged, the positive current of the pole core 100 can be transmitted to the electrical device through the first pole lug group 200a and the first pole, and the negative current of the pole core 100 can be transmitted to the electrical device through the second pole lug group 200b and the second pole.

[0087] The multiple tabs of the first tab group 200a are fixedly connected by first weld marks 210. The first tab group 200a is fixedly connected to the first terminal post via welds 400. Furthermore, for the first tab group 200a and the first terminal post, the orthographic projection of the welds 400 in the thickness direction of the first tab group 200a is located within the orthographic projection of the corresponding bottom surface 211 in the thickness direction of the first tab group 200a. This eliminates the need for a connecting piece between the first tab group 200a and the first terminal post, thereby increasing the volumetric energy density of the battery 10 and improving the welding performance between the first tab group 200a and the first terminal post.

[0088] The multiple tabs of the second tab group 200b are fixedly connected by the first weld mark 210. The second tab group 200b is fixedly connected to the second electrode via the weld portion 400. Furthermore, for the second tab group 200b and the second electrode, the orthographic projection of the weld portion 400 in the thickness direction of the second tab group 200b is located within the orthographic projection of the corresponding bottom surface 211 in the thickness direction of the second tab group 200b. In this way, the connecting piece between the second tab group 200b and the second electrode can be eliminated, thereby increasing the volumetric energy density of the battery 10 and improving the welding performance between the second tab group 200b and the second electrode.

[0089] Reference Figures 1 to 3As shown, in some embodiments, the two tab groups 200 include a first tab group 200a and a second tab group 200b, with the first tab group 200a and the second tab group 200b having opposite electrical polarities. The battery 10 also includes a housing 500, which has a receiving cavity in which the electrode core 100, the first tab group 200a, and the second tab group 200b are all accommodated. The polar member 300 includes a first electrode post. The first tab group 200a has a first weld mark 210 on the side facing away from the first electrode post. The first tab group 200a and the first electrode post are connected by a weld 400. The first electrode post is insulated and disposed in the housing 500. The second tab group 200b has a first weld mark 210 along the thickness direction of the second tab group 200b on the side facing away from the housing 500. The second tab group 200b and the housing 500 are connected by a weld 400.

[0090] For example, the housing 500 may include a first housing wall, the first electrode post is insulated and disposed on the first housing wall to prevent a short circuit in the battery 10, and the second electrode tab group 200b is fixedly connected to the first housing wall so that the second electrode tab group 200b is electrically connected to the housing 500. The first electrode tab group 200a and the first electrode post are both positively charged, and the second electrode tab group 200b and the housing 500 are both negatively charged. The positive current of the electrode core 100 can be transmitted to the electrical device through the first electrode tab group 200a and the first electrode post, and the negative current of the electrode core 100 can be transmitted to the electrical device through the second electrode tab group 200b and the housing 500.

[0091] The multiple tabs of the first tab group 200a are fixedly connected by first weld marks 210. The first tab group 200a is fixedly connected to the first terminal post via welds 400. Furthermore, for the first tab group 200a and the first terminal post, the orthographic projection of the welds 400 in the thickness direction of the first tab group 200a is located within the orthographic projection of the corresponding bottom surface 211 in the thickness direction of the first tab group 200a. This eliminates the need for a connecting piece between the first tab group 200a and the first terminal post, thereby increasing the volumetric energy density of the battery 10 and improving the welding performance between the first tab group 200a and the first terminal post.

[0092] The multiple tabs of the second tab group 200b are fixedly connected by first weld marks 210. The second tab group 200b is fixedly connected to the first shell wall via welds 400. With respect to the second tab group 200b and the first shell wall, the orthographic projection of the welds 400 in the thickness direction of the second tab group 200b is located within the orthographic projection of the corresponding bottom surface 211 in the thickness direction of the second tab group 200b. This eliminates the need for a connecting sheet between the second tab group 200b and the first shell wall, thereby increasing the volumetric energy density of the battery 10 and improving the welding performance between the second tab group 200b and the first shell wall.

[0093] Based on the above embodiments, the present application also provides a battery assembly, which includes a circuit structure and at least one battery 10 provided in the above embodiments, wherein the circuit structure is electrically connected to the battery 10. The structure and operating principle of the battery 10 have been described in detail in the above embodiments and will not be repeated here.

[0094] For example, the circuit structure may be a PCM (Protection Circuit Module) to provide charge and discharge protection, short circuit protection, etc. for the battery 10. The circuit structure may also be a connector for connecting multiple batteries 10 in series or in parallel. No specific limitation is imposed on the circuit structure herein.

[0095] Based on the above embodiments, the present application provides an electrical device, comprising an electrical device and the battery 10 or battery assembly provided in the above embodiments. The battery 10 or battery assembly is used to power the electrical device. The structure and operating principles of the battery 10 and battery assembly have been described in detail in the above embodiments and will not be further elaborated here.

[0096] Exemplarily, the power-consuming device may be an electronic device such as a mobile phone or a tablet computer. The electronic device such as a mobile phone or a tablet computer may include power-consuming devices such as a central processing unit and a display screen. The battery 10 is conductively connected to the power-consuming device, so that the current of the battery 10 is transmitted to the power-consuming device.

[0097] For another example, the electrical equipment may be a vehicle, the electrical device may be an electric motor, and the battery 10 may provide electrical energy to the motor, thereby driving the vehicle. The vehicle may be a pure electric vehicle, an extended-range electric vehicle, a hybrid electric vehicle, or any other vehicle having the battery 10.

[0098] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A battery, characterized in that: include: A tab group (200), the tab group (200) comprising a plurality of tabs stacked together; Polar piece (300); Along the thickness direction of the tab group (200), the side of the tab group (200) facing away from the polar member (300) includes a first side surface (220) and at least one first weld mark (210), wherein the first weld mark (210) is used to fixedly connect at least a portion of the tab; the first weld mark (210) is recessed toward the polar member (300) relative to the first side surface (220), and the first weld mark (210) includes a bottom surface (211), and the bottom surface (211) is located at one end of the first weld mark (210) close to the polar member (300); At least one welding portion (400), along the thickness direction of the tab group (200), the orthographic projection of the welding portion (400) is located within the orthographic projection of the bottom surface (211), and / or the orthographic projection of the welding portion (400) and the orthographic projection of the bottom surface (211) completely overlap, and the welding portion (400) fixedly connects the tab group (200) and the polar member (300).

2. The battery according to claim 1, characterized in that The bottom surface (211) is at least one of a flat surface and a curved surface.

3. The battery according to claim 2, characterized in that The bottom surface (211) is a plane, and the area of ​​the bottom surface (211) is greater than or equal to 0.0078 mm. 2 .

4. The battery according to claim 3, characterized in that The bottom surface (211) is circular, and the radius of the bottom surface (211) has a value range of [0.05 mm, 0.15 mm].

5. The battery according to claim 1, characterized in that The geometric center line of the welding portion (400) coincides with the geometric center point of the bottom surface (211).

6. The battery according to claim 1, characterized in that There is an angle between the plane where the side of the polar member (300) facing the tab group (200) is located and the plane where the bottom surface (211) is located, and the value range of the angle is: [0°, 5°].

7. The battery according to claim 1, characterized in that The tab group (200) comprises a second side surface (230) arranged opposite to the polar member (300), the second side surface (230) being provided with at least one second weld mark (240), and the second weld mark (240) and at least part of the first weld mark (210) being arranged correspondingly.

8. The battery according to claim 1, characterized in that The first weld mark (210) further includes a side surface (212), the side surface (212) including a first end portion (2121) and a second end portion (2122) arranged opposite to each other along the thickness direction of the tab group (200), the first end portion (2121) being connected to the first side surface (220), and the second end portion (2122) being connected to the bottom surface (211); The tab group (200) comprises a second side surface (230) disposed opposite to the polar member (300); along the thickness direction of the tab group (200), the distance between the first side surface (220) and the second side surface (230) is the thickness T of the tab group (200); Along the thickness direction of the tab group (200), the maximum distance D between the first end (2121) and the second end (2122) and the thickness T of the tab group (200) satisfy the following relationship: 20%T≤D≤70%T.

9. The battery according to claim 8, characterized in that Along the thickness direction of the tab group (200), the orthographic projection of the second end portion (2122) is located within the orthographic projection of the first end portion (2121).

10. The battery according to claim 1, characterized in that The side of the tab group (200) facing away from the polar member (300) includes a plurality of first weld marks (210), the plurality of first weld marks (210) are arranged at intervals, and the minimum spacing between two adjacent first weld marks (210) is greater than or equal to 0.05 mm.

11. The battery according to any one of claims 1 to 10, characterized in that: At least two welding portions (400) are provided in at least a portion of the first welding mark (210).

12. The battery according to any one of claims 1 to 10, characterized in that: There are a plurality of first welding marks (210), and each of the first welding marks (210) is provided with at least one welding portion (400).

13. The battery according to any one of claims 1 to 10, characterized in that: The tab group (200) comprises at least one first tab group (200a) and at least one second tab group (200b), wherein the first tab group (200a) and the second tab group (200b) have opposite polarities; The polar member (300) comprises a first polar member and a second polar member, the first tab group (200a) has the first welding mark (210) on a side facing away from the first polar member, and the welding portion (400) fixedly connects the first tab group (200a) and the first polar member; The second tab group (200b) has the first welding mark (210) on a side facing away from the second polarity member, and the welding portion (400) fixedly connects the second tab group (200b) and the second polarity member.

14. A battery assembly, characterized in that: The invention comprises at least one battery (10) according to any one of claims 1 to 13 and a circuit structure, wherein the battery (10) is electrically connected to the circuit structure.

15. An electrical device, characterized in that: Comprising the battery (10) according to any one of claims 1 to 13, and / or the battery assembly according to claim 14.

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