Battery and electronic device

Abstract

The utility model provides a battery and an electronic device, and relates to the technical field of batteries. The naked battery cell is arranged in the shell assembly, the naked battery cell comprises a positive plate, a negative plate and a diaphragm, the positive plate, the diaphragm and the negative plate are sequentially stacked and wound around a winding axis, and a tab is arranged at one end, along the winding axis, of the naked battery cell; the electrode adapter plate is welded with the tabs to form at least one continuous welding mark, at least part of the welding mark extends from the outer circumference of the naked battery cell to the inner circumference of the naked battery cell, the welding mark comprises an arc-shaped section, and the radius of curvature of any position of the welding mark is greater than or equal to 0.5 mm. According to the battery, the tabs of the naked battery core and the welding marks of the electrode adapter plates comprise the arc-shaped sections, and the curvature radius of any point on the welding marks is greater than or equal to 0.5 mm, so that the problems of welding energy concentration and welding point explosion caused by the welding energy concentration can be avoided, the welding heat is prevented from penetrating through the tabs to burn active substances in the battery, and the welding quality is ensured.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, in particular to a battery and an electronic device. Background Art

[0002] With the development of society, more and more electrical equipment uses batteries as energy storage and supply devices, such as new energy vehicles, communication base stations, energy storage containers, etc. A battery generally includes a bare battery cell inside and a housing assembly. The tabs of the bare battery cell are electrically connected to the electrode output terminals on the battery through electrode adapter plates.

[0003] Currently, for some models of batteries, wire welding is used for welding between the tabs and the electrode adapter plates. In order to increase the welding area, a wavy welding track is adopted. Due to the sharp change in the radius of curvature of the transition point area on the welding track, the welding energy will be concentrated in the transition point area, and the generated welding heat will accumulate and penetrate the tabs, resulting in the problem of burning the active substances inside the battery. Summary of the Utility Model

[0004] In view of the above problems, the utility model provides a battery and an electronic device, where the radius of curvature R at any point of the weld mark is greater than or equal to 0.5 mm, which can avoid the concentration of welding energy and the resulting welding explosion point problem, ensure the welding quality, and improve the product qualification rate.

[0005] The utility model provides a battery, including: a housing assembly; a bare battery cell disposed inside the housing assembly, the bare battery cell including: a positive electrode plate, a negative electrode plate, and a separator, the positive electrode plate, the separator, and the negative electrode plate are sequentially stacked and wound around a winding axis, and a tab is provided at one end of the bare battery cell along the winding axis; an electrode adapter plate, the electrode adapter plate is welded to the tab and forms at least one continuous weld mark, at least a part of the weld mark extends from the outer periphery of the bare battery cell to the inner periphery, the weld mark includes an arc segment, and the radius of curvature at any point of the weld mark is greater than or equal to 0.5 mm.

[0006] In some embodiments, the weld mark has an extension reference line, and the extension reference line divides the weld mark into a plurality of welding segments arranged in sequence along the extension direction of the extension reference line, and any two adjacent welding segments are respectively located on opposite sides of the extension reference line.

[0007] In some embodiments, the extension reference line is a straight line.

[0008] In some embodiments, among the plurality of welding segments, at least the welding segments other than those at both ends of the weld mark have transition points, the distance between the transition point and the extension reference line is greater than the distance between any point on both sides of the transition point and the extension reference line, and the transition point is located on the arc segment.

[0009] In some embodiments, the distances between the transition points of any two welding segments and the extension reference line are equal.

[0010] In some embodiments, any two adjacent welding segments are centrosymmetric about the connection point of the two welding segments.

[0011] In some embodiments, the welding segment is arc-shaped; alternatively, the welding segment includes an arc segment and non-arc segments on both sides of the arc segment.

[0012] In some embodiments, when the welding segment is arc-shaped, the welding segment is a part of a circle.

[0013] In some embodiments, the height-span ratio A of the welding segment satisfies: 0 < A < 3, where A = H / L, H is the distance between the transition point of the welding segment and the line connecting the two ends of the welding segment, and L is the length of the line connecting the two ends of the welding segment.

[0014] In some embodiments, the height-span ratio A of the welding segment satisfies: 0.25 ≤ A ≤ 1.

[0015] In some embodiments, the width w of the welding mark ranges from 0.2 mm to 0.8 mm.

[0016] In some embodiments, the radius of curvature R at the point with the minimum radius of curvature on the welding mark min satisfies: 2R min - w ≥ 0.5 mm.

[0017] In some embodiments, the welding mark has a first end close to the center of the bare battery cell and a second end far from the center of the bare battery cell along the extension reference line. The distance L1 between the first end and the second end satisfies: 6 mm ≤ L1 ≤ 15 mm; and / or, the distance L2 between the first end and the center of the bare battery cell in the direction of the extension reference line satisfies: 0 mm ≤ L2 ≤ 10 mm; and / or, the maximum distance L3 between the second end and the edge of the bare battery cell in the direction of the extension reference line satisfies: 0 mm ≤ L3 ≤ 10 mm.

[0018] In some embodiments, there are multiple welding marks, and the extension reference line of each welding mark extends along the radial direction of the bare battery cell, and the multiple welding marks are arranged at intervals along the circumferential direction of the bare battery cell.

[0019] In some embodiments, there are multiple welding marks, and the multiple welding marks are divided into several welding groups. The several welding groups are arranged at intervals along the circumferential direction of the bare battery cell. Each welding group includes several parallel and spaced welding marks. Moreover, the extension reference line of one of the welding marks in each welding group extends along the radial direction of the bare battery cell, and the distance L4 between two adjacent welding marks belonging to the same welding group satisfies: 0.5 mm ≤ L4 ≤ 5 mm.

[0020] In some embodiments, at one end of the bare battery cell along the winding axis, the end of the separator extends beyond the end of the positive electrode sheet, the end of the negative electrode sheet extends beyond the end of the separator, and the part of the negative electrode sheet extending beyond the separator includes a tab. The tab includes a plurality of independently bendable connecting pieces, and the plurality of connecting pieces are all bent towards the center of the bare battery cell. After bending, the plurality of connecting pieces form a tab end face. The value range of the distance D between the tab end face and the separator in the axial direction of the bare battery cell is: 1 mm ≤ D ≤ 2 mm.

[0021] In some embodiments, the tab is a copper tab and the electrode adapter piece is a copper sheet.

[0022] The second aspect of the present utility model provides an electronic device, including: the battery according to the first aspect of the present utility model.

[0023] According to the battery of the present utility model, the welding marks of the tab of the bare battery cell and the electrode adapter piece include an arc section, and the radius of curvature R at any point on the welding mark is greater than or equal to 0.5 mm. At least it can increase the distance between the parts on both sides of the transition point of the arc section, avoid the overlap of the heat affected zones on both sides of the transition point, avoid the concentration of welding energy and the resulting welding explosion point problem, thereby avoiding the welding heat from penetrating the tab and burning the active substances and the separator inside the bare battery cell, ensuring the welding quality, improving the product qualification rate, and being beneficial to large-scale production and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0025] Figure 1 It is a schematic structural diagram of a battery according to some embodiments of the present utility model;

[0026] Figure 2 For Figure 1 The sectional view along the middle section A-A;

[0027] Figure 3 It is a schematic structural diagram of a bare battery cell according to some embodiments of the present utility model;

[0028] Figure 4 It is a schematic diagram of the welding mark distribution of a battery according to some embodiments of the present utility model;

[0029] Figure 5 It is a schematic diagram of the welding mark distribution of a battery according to other embodiments of the present utility model;

[0030] Figure 6Schematic diagram of the welding mark structure of the battery according to some embodiments of the present utility model;

[0031] Figure 7 Schematic diagram of the structure of the welding mark according to some embodiments of the present utility model;

[0032] Figure 8 Schematic diagram of the structure of the welding mark according to some embodiments of the present utility model;

[0033] Figure 9 Schematic diagram of the structure of the welding mark according to some embodiments of the present utility model;

[0034] Figure 10 Schematic diagram of the structure of the welding mark according to some embodiments of the present utility model;

[0035] Figure 11 Schematic diagram of the structure of the welding mark according to some embodiments of the present utility model;

[0036] Figure 12 Schematic diagram of the structure of the welding mark according to some embodiments of the present utility model;

[0037] Figure 13 Schematic diagram of the formation process of the welding mark according to an embodiment of the present utility model;

[0038] Figure 14 Welding effect diagram when the height-width ratio of the welding mark is 0.25;

[0039] Figure 15 Welding effect diagram when the height-width ratio of the welding mark is 0.5;

[0040] Figure 16 Welding effect diagram when the height-width ratio of the welding mark is 1;

[0041] Figure 17 Welding effect diagram when the height-width ratio of the welding mark is 2;

[0042] Figure 18 Welding effect diagram when the height-width ratio of the welding mark is 3.

[0043] Explanation of reference numerals:

[0044] 100 - Battery;

[0045] 1 - Bare battery cell;

[0046] 111 - Positive electrode plate; 1111 - Positive current collector; 1112 - Positive active coating; 1113 - Positive tab;

[0047] 112 - Negative electrode plate; 1121 - Negative current collector; 1122 - Negative active coating;

[0048] 113 - Diaphragm; 114 - Tab; 1140 - Connecting piece; 1141 - Tab end face;

[0049] 2 - Electrode adapter piece;

[0050] 3 - Welding mark; 31 - Welding section; 32 - Arc section;

[0051] 4 - Welding group;

[0052] 5 - Housing assembly; 51 - Outer housing; 511 - Top wall; 512 - Side wall; 52 - Cover plate;

[0053] 6 - Positive current collector plate; 7 - Terminal post;

[0054] B - Welding focus; N - Extension reference line; G - Transition point;

[0055] 200 - Welding equipment. Detailed implementation manners

[0056] In order to make the above - mentioned objects, features, and advantages of the embodiments of the present application more obvious and understandable, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without making creative efforts shall fall within the scope of protection of the present application.

[0057] With the development of society, more and more electronic devices use batteries as energy storage and supply devices. The electronic devices can be vehicles, mobile phones, portable devices, laptop computers, ships, spacecrafts, electric toys, and power tools, etc. Vehicles can be fuel - powered vehicles, gas - powered vehicles, or new - energy vehicles. New - energy vehicles can be pure - electric vehicles, hybrid vehicles, or range - extender vehicles, etc. Spacecrafts include airplanes, rockets, space shuttles, and spaceships, etc. Electric toys include fixed or mobile electric toys, such as game consoles, electric vehicle toys, electric ship toys, and electric airplane toys, etc. Power tools include metal - cutting power tools, grinding power tools, assembly power tools, and railway - use power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact electric drills, concrete vibrators, and electric planers, etc. The electronic devices can also be battery packs, battery modules, etc. The embodiments of the present application do not make special limitations on the above - mentioned electronic devices.

[0058] The electronic device can include: a device main body and a battery. The device main body can include a battery compartment. The battery is arranged in the battery compartment and is electrically connected to the device main body. For example, a power supply interface can be arranged in the battery compartment, and the battery can be connected to the power supply interface.

[0059] In the embodiments of the present application, the battery can be a primary battery or a secondary battery. A primary battery refers to a battery that cannot be recharged and reused after discharging, and a secondary battery refers to a battery that can be activated by charging after discharging and can continue to be used. The battery can be a lithium-ion battery, a sodium-ion battery, a sodium-lithium-ion battery, a lithium metal battery, a sodium metal battery, a lithium-sulfur battery, a magnesium-ion battery, a nickel-cadmium battery, etc., and the embodiments of the present application are not limited thereto.

[0060] At present, for some models of batteries, wire welding is used for the welding between the tab and the electrode adapter. In order to increase the welding area, a wavy welding track is adopted. Since the curvature radius of some areas on the welding track changes sharply, it will cause the welding energy to concentrate in the corresponding areas, and the generated welding heat accumulates and penetrates the tab, resulting in the problem of burning the active substances inside the battery.

[0061] In view of this, this embodiment provides a battery and an electronic device. The radius of curvature R of any point on the welding mark satisfies R≥0.5 mm, which can increase the distance between any two points on the welding track, avoid the overlap of the heat affected zones of the front and rear welding areas, avoid the concentration of welding energy and the resulting welding explosion point problem, avoid the welding heat from penetrating the tab and burning the active substances and the separator inside the bare battery cell, ensure the welding quality, improve the product qualification rate, and is conducive to large-scale production and application. In addition, the radius of curvature R in this application refers to the radius of curvature of the line obtained by connecting the midpoints in the width direction of the welding mark.

[0062] Combined Figures 1-18 with

[0063] Reference Figure 1 and Figure 2 , the battery 100 of this embodiment includes: a housing assembly 5, a bare battery cell 1, and an electrode adapter 2.

[0064] The battery 100 may further include a positive current collector plate 6 and a terminal 7. The terminal 7 passes through the top wall 511, and the terminal 7 is welded to the positive current collector plate 6, and the terminal 7 serves as the positive output terminal of the battery 100.

[0065] Reference Figure 3, the bare battery cell 1 can be disposed in the accommodating cavity. The bare battery cell 1 may include a positive electrode sheet 111, a negative electrode sheet 112, and a separator 113. Among them, the positive electrode sheet 111 includes a positive electrode current collector 1111 and a positive electrode active coating 1112 coated on the surface of the positive electrode current collector 1111. The negative electrode sheet 112 includes a negative electrode current collector 1121 and a negative electrode active coating 1122 coated on the surface of the negative electrode current collector 1121. Taking the battery 100 as a cylindrical battery as an example, the positive electrode sheet 111, the separator 113, and the negative electrode sheet 112 are sequentially stacked and then wound around the winding axis to form a wound bare battery cell 1.

[0066] An electrode tab 114 may be provided at one end of the bare battery cell 1 along the winding axis. The electrode tab 114 may be the negative electrode tab of the bare battery cell 1. A positive electrode tab 1113 is provided at one end of the bare battery cell 1 facing the top wall 511. The positive electrode tab 1113 and the terminal post 7 are electrically connected through a positive electrode current collecting plate 6.

[0067] The electrode tab 114 may include a plurality of connecting pieces 1140, that is, a plurality of connecting pieces 1140 together form the electrode tab 114. Among them, each connecting piece 1140 is an uncoated active coating empty foil area of the current collector extending from the body of the bare battery cell 1. At least a part of the plurality of connecting pieces 1140 is distributed along the circumferential direction of the bare battery cell 1. For example, the plurality of connecting pieces 1140 may be arranged in an array along both the circumferential direction and the radial direction of the bare battery cell 1.

[0068] It can be understood that when the positive electrode sheet 111, the separator 113, and the negative electrode sheet 112 are stacked and then wound, on the negative electrode side of the bare battery cell 1, due to the part of the negative electrode current collector 1121 that exceeds the negative electrode active coating 1122, that is, when the empty foil area of the negative electrode current collector 1121 is a continuous surface, there will be more wrinkles when being flattened. And the plurality of connecting pieces 1140 in this embodiment are formed by dividing this empty foil area into multiple segments. In this way, the length of each connecting piece 1140 in the circumferential direction of the bare battery cell 1 can be reduced. When the connecting pieces 1140 are bent and stacked on each other, the generation of wrinkles can be reduced or even avoided, so that the electrode tab end face 1141 formed by bending the plurality of connecting pieces 1140 is flatter. It can be understood that the electrode tab end face 1141 is the surface at one end of the bare battery cell 1 after the plurality of connecting pieces 1140 are bent and stacked, which is beneficial to improving the welding effect between the electrode tab 114 and the electrode adapter piece 2. Correspondingly, on the positive electrode side of the bare battery cell 1, the empty foil area of the positive electrode current collector 1111 can also be divided into a plurality of connecting pieces.

[0069] Combined with Figures 1-3, the electrode adapter 2 can be a copper sheet to facilitate welding with the copper foil serving as the tab 114. The electrode adapter 2 is welded to the tab 114 and forms at least one continuous weld mark 3. The continuous weld mark 3 means that there is no breakpoint on a single weld mark 3. At least part of the weld mark 3 extends from the outer periphery to the inner periphery of the bare cell 1. Since the positive electrode sheet 111, the separator 113, and the negative electrode sheet 112 are wound around a winding needle to form the bare cell 1, a central hole is formed at the central position of the bare cell 1 along its radial direction, making the cross-section of the bare cell 1 perpendicular to the central axis annular. The outer periphery of the bare cell 1 is the outer contour position of the ring, and the inner periphery is the inner contour position of the ring. Thus, when the electrode adapter 2 is welded to the tab 114, the electrode adapter 2 can be welded to at least part of the plurality of connecting pieces 1140 to form the weld mark 3. Moreover, at least part of the weld mark 3 extends radially, enabling as many layers of tabs 114 as possible to be connected to the electrode adapter 2, increasing the connection area, and reducing the internal resistance of the battery. Among them, the welding method can be laser welding, ultrasonic welding, or other welding methods. Optionally, the electrode adapter 2 can also be connected to the housing 51 so that the housing 51 serves as the negative output terminal of the battery 100.

[0070] Combined with Figures 4-12 , the weld mark 3 includes an arc segment 32, and the radius of curvature at any point of the weld mark 3 is greater than or equal to 0.5 mm. For example, the weld mark 3 can be composed only of the arc segment 32, and at this time, the radius of curvature at any point on each arc segment 32 is greater than or equal to 0.5 mm; or the weld mark 3 can be composed of the arc segment 32 and a straight segment. At this time, the radius of curvature at any point on the arc segment 32 is greater than or equal to 0.5 mm, and the radius of curvature of the straight segment is infinite, that is, the radius of curvature of the straight segment satisfies being greater than or equal to 0.5 mm. In this way, the radius of curvature at any point of the weld mark 3 can also be greater than or equal to 0.5 mm.

[0071] When there is an arc segment 32 in the weld mark 3, during the welding process, the welding travel speed of the welding device 200 (such as the welding head of the laser welding device 200) at the point with the minimum radius of curvature of the arc segment 32 (i.e., the transition point G below) will decrease, and the parts on both sides of the transition point G are relatively close, resulting in the parts on either side of the transition point G being in the heat-affected zone of the other side, that is, the heat-affected zones on both sides of the transition point G overlap, thereby causing welding energy concentration at the transition point G and the surrounding area, and resulting in the problem of welding explosion points, as Figures 16-18As shown. To avoid the concentration of welding energy at the transition point G, in this embodiment, the weld mark 3 is configured such that the radius of curvature at any point is greater than or equal to 0.5 mm. Of course, the specific values of the radius of curvature at each part of the weld mark 3 can be reasonably selected according to needs. By making the radius of curvature meet the above range, at least it can ensure that the transition angle at the transition point G of the arc segment 32 becomes smaller, and the distance between the parts on both sides of the transition point G becomes larger, thereby avoiding the overlap of the heat affected zones on both sides of the transition point G, and further avoiding the problem of concentrated welding energy, as Figures 14-15 shown.

[0072] For the battery 100 according to the embodiment of the present utility model, the weld mark 3 between the tab 114 of the bare battery cell 1 and the electrode adapter 2 includes an arc segment 32, and the radius of curvature at any point on the weld mark 3 is greater than 1 mm. At least it can make the distance between the parts on both sides of the point with the minimum radius of curvature of the arc segment 32 become larger, avoid the overlap of the heat affected zones on both sides of the point with the minimum radius of curvature, avoid the problem of concentrated welding energy and the resulting welding explosion point problem, thereby avoiding the welding heat from penetrating the tab and burning the active material and the separator inside the bare battery cell 1, ensuring the welding quality, improving the product qualification rate, and being beneficial to large-scale production and application.

[0073] Combined with Figures 4-12 , the weld mark 3 has an extended reference line N. The extended reference line N is a virtual reference line, and the extended reference line N represents the overall extension direction of the welding track of the weld mark 3. The extended reference line N can be a straight line or a curve such as a U shape, a spiral shape, etc. The extended reference line N divides the weld mark 3 into multiple welding segments 31. The multiple welding segments 31 are arranged in sequence along the extension direction of the extended reference line N, and any two adjacent welding segments 31 are respectively located on opposite sides of the extended reference line N. In this way, at least it can make the other welding segments 31 except those at both ends of the weld mark 3 protrude away from the extended reference line N. At this time, the weld mark 3 between the tab 114 and the electrode adapter 2 is wavy, enabling the weld mark 3 to connect a plurality of connecting pieces 1140 distributed circumferentially and a plurality of connecting pieces 1140 distributed radially with the electrode adapter 2, increasing the welding area, improving the connection strength, and being beneficial to improving the reliability of welding.

[0074] In a specific example, combined with Figures 6-12 , the extended reference line N is a straight line. At this time, the multiple welding segments 31 can be distributed in sequence along the straight line. In this way, the structure of the weld mark 3 is simplified. Compared with the scheme where the extended reference line N is a curve, it can reduce the welding process difficulty and is beneficial to ensuring the welding quality.

[0075] Furthermore, combined with Figures 10-12, among the multiple welding segments 31, at least the welding segments 31 other than those located at both ends of the welding mark 3 have a transition point G, and the distance between the transition point G and the extension reference line N is greater than the distance between any point on both sides of the transition point G and the extension reference line N. In other words, the transition point G is the point on the welding segment 31 that is farthest from the extension reference line N, and at least the part of the welding segment 31 where the transition point G is located constitutes the arc segment 32 of the welding mark 3.

[0076] For example, among the multiple welding segments 31 arranged in a straight line, a welding segment 31 close to the outer periphery of the bare battery cell 1 is the head welding segment, and a welding segment 31 close to the inner periphery of the bare battery cell 1 is the tail welding segment. In this embodiment, the remaining welding segments other than the head welding segment and the tail welding segment have a transition point G, and the head welding segment and the tail welding segment may both not have a transition point G, as Figure 12 shown; or, at least one of the head welding segment and the tail welding segment may also have a transition point G, as Figure 10 and Figure 11 shown.

[0077] Optionally, referring to Figure 11 , in the case where the head welding segment and the tail welding segment have a transition point G, the head welding segment and the tail welding segment may have one intersection point with the extension reference line N. At this time, only the part of the head welding segment and the tail welding segment on one side of the transition point G extends to the extension reference line N, and the part on the other side of the transition point G does not intersect with the extension reference line N; or, referring to Figure 10 , both the head welding segment and the tail welding segment have two intersection points with the extension reference line N, that is, the parts on both sides of the transition point G extend to the extension reference line N.

[0078] Among them, the part of each welding segment 31 where the transition point G is located constitutes the arc segment 32. For example, each welding segment 31 may be integrally formed as an arc. At this time, the welding segment 31 is the above-mentioned arc segment 32; or, the area of the transition point G of each welding segment 31 is an arc, and the areas on both sides of the transition point G area may be other shapes. At this time, only the part of the welding segment 31 where the transition point G is located constitutes the above-mentioned arc segment 32.

[0079] In some embodiments, the distances between the transition points G of any two welding segments 31 and the extension reference line N are equal. In other words, the extension reference line N is at the middle of the welding mark 3 in its own height direction.

[0080] In some embodiments, referring to Figures 4-6 and Figure 10, any two adjacent welding segments 31 are centrosymmetric about the connection point of the two welding segments 31. Here, centrosymmetry means that for two adjacent welding segments 31, one of them coincides with the other after rotating 180° around their connection point. At this time, the opening directions of any two adjacent welding segments 31 are opposite. In this way, the solder mark 3 composed of multiple welding segments 31 is formed into a wavy shape as a whole, that is, the welding track of the electrode adapter 2 and the multiple tabs 114 is wavy. Since the extended shape of the solder mark 3 is not a straight line and has a certain span in the circumferential direction of the bare battery cell 1, each welding segment 31 of the solder mark 3 can be connected to several connection pieces 1140 distributed in the circumferential direction, and at the same time, the solder mark 3 as a whole can also be connected to several connection pieces 1140 distributed in the radial direction, thereby increasing the connection area between the electrode adapter 2 and the tab 114, improving the welding strength, reducing the current transmission path, and reducing the internal resistance of the battery 100.

[0081] In some embodiments, in combination with Figures 7-9 , the welding segment 31 can be arc-shaped. For example, the welding segment 31 can be circular arc-shaped or non-circular arc-shaped. At this time, the overall shape of the solder mark 3 is close to a sine track; alternatively, the welding segment 31 includes an arc segment 32 and non-arc segments 32 located on both sides of the arc segment 32. The non-arc segments 32 can be straight line segments or other shapes. In this way, it can be ensured that each welding segment 31 of the solder mark 3 has a certain span in the circumferential direction to connect multiple connection pieces 1140 distributed in the circumferential direction, and moreover, the form of the solder mark 3 is relatively diverse, the structure is relatively simple, and it is easy to implement.

[0082] Preferably, the welding segment 31 is formed as a part of a circle. Specifically, it can be a semi-circle, which can make the transition at the transition point G of the solder mark 3 smooth, and moreover, the curvature radii of all points on the solder mark 3 are the same, which is convenient for the smooth movement of the laser welding equipment, the welding quality of each point is good, the welding depth is uniform, and it can better avoid the problems of energy accumulation and generation of explosion points. And using a semi-circular track can enable the solder mark to weld multiple connected tabs 114, so that the welding tensile force is higher and the quality is more reliable. When the welding segment 31 is semi-circular, preferably, the diameter of the welding segment 31 is 1 mm - 2 mm to fully avoid the problems of energy accumulation and generation of explosion points at the transition point G of the solder mark 3.

[0083] In some embodiments, referring to Figure 7, the height-span ratio A of the welding section 31 satisfies: 0 < A < 3. Specifically, the height-span ratio A of the welding section 31 = H / L, where H is the distance between the transition point G of the welding section 31 and the connection line between the two ends of the welding section 31, that is, the height of the welding section 31; L is the length of the connection line between the two ends of the welding section 31, that is, the span of the welding section 31. Among them, the value of H affects the span of the welding section 31 in the circumferential direction of the bare battery cell 1, thereby affecting the welding area between the electrode adapter 2 and the tab 114 in the circumferential direction, as well as the current-carrying capacity at the weld mark 3, while L affects the size of the corner at the welding section 31.

[0084] For example, the height-span ratio of the welding section 31 can be 0.5, 1, 1.5, 2, 2.5, etc. Of course, the present invention does not limit this. In this way, it can be ensured that the height of the welding section 31 in the circumferential direction of the bare battery cell 1 is relatively large, so as to increase the number of connection pieces 1140 covered by the welding section 31 in the circumferential direction, increase the welding area, improve the current-carrying capacity, and make the transition point G of the welding section 31 smoother to avoid the concentration of welding energy.

[0085] Furthermore, the height-span ratio A of the welding section 31 satisfies: 0.25 ≤ A ≤ 1. For example, the height-span ratio of the welding section 31 can be 0.25, 0.5, 0.6, 0.7, 0.8, 0.9, etc. Of course, the present invention does not limit this. In this way, while ensuring the welding area of the welding section 31, the smoothness of the welding section 31 at the transition point G is further improved to avoid the concentration of welding energy and improve the welding quality.

[0086] Reference Figures 14-18 , among which Figure 14 shows the welding effect at the transition point G of the welding section 31 when the height-span ratio of the welding section 31 is 0.25; Figure 15 shows the welding effect at the transition point G of the welding section 31 when the height-span ratio of the welding section 31 is 0.5; Figure 16 shows the welding effect at the transition point G of the welding section 31 when the height-span ratio of the welding section 31 is 1; Figure 17 shows the welding effect at the transition point G of the welding section 31 when the height-span ratio of the welding section 31 is 2; Figure 18 shows the welding effect at the transition point G of the welding section 31 when the height-span ratio of the welding section 31 is 3. According to Figures 14-18It can be seen that when the height-width ratio is 3, due to the excessive transition angle at the transition point G of the welding section 31 and the short distance between the parts on both sides of the transition point G, the area around the transition point G is greatly affected by the welding heat, and there is a dark area caused by the concentration of welding heat. This area is not conducive to improving the welding quality between the tab 114 and the electrode adapter 2. When the height-width ratio is 2, the area around the transition point G of the welding section 31 is less affected by the welding heat, which can improve the welding quality between the tab 114 and the electrode adapter 2. When the height-width ratio is 0.25, 0.5, or 1, the problem of welding heat concentration in the area around the transition point G of the welding section 31 is small, and it is basically not affected by the concentration of welding heat, which can reliably ensure the welding quality between the tab 114 and the electrode adapter 2.

[0087] In some embodiments, the width w of the weld mark 3 ranges from 0.2 mm to 0.8 mm. That is to say, the width w of each welding section 31 in the direction perpendicular to its own extension ranges from 0.2 mm to 0.8 mm. For example, the width w of the weld mark 3 can be 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, or 0.8 mm. Of course, the present utility model does not limit this. In this way, it can be avoided that when the width of the weld mark 3 is too small, such as less than 0.2 mm, the welding area is too small, the welding reliability is low, and the resistance value at the weld mark 3 is large, which affects the overcurrent capacity. It can also be avoided that when the width of the weld mark 3 is too large, such as greater than 0.8 mm, the heat-affected zones on both sides of the transition point G of the welding section 31 overlap, resulting in the phenomenon of concentrated welding energy. In summary, it can not only ensure that the welding area at the weld mark 3 is large enough to ensure the overcurrent capacity, but also ensure as much as possible that there is no problem of concentrated welding energy affecting the welding quality.

[0088] In addition, referring to Figure 13 , when using laser welding, the closer the welding focus B is to the welding surface (i.e., the surface of the electrode adapter 2), the more concentrated the welding heat is, and the more likely it is to have the problem of welding explosion points. The farther the welding focus B is from the welding surface, the more dispersed the welding energy is, and it is difficult to penetrate the electrode adapter 2 to reach the tab 114, resulting in virtual welding and false welding. Therefore, in this embodiment, by keeping the welding focus B at an appropriate distance from the welding surface, the width range of the weld mark 3 can be maintained at 0.2 mm to 0.8 mm. In this way, it can not only avoid the problem of welding explosion points caused by concentrated welding energy, but also ensure the connection strength between the electrode adapter 2 and the tab 114, with better processability and higher reliability.

[0089] In some embodiments, referring to Figure 6, the value range of the diameter R2 of the bare battery cell 1 can be: 22 mm ≤ R2 ≤ 45.2 mm. For example, the diameter R2 of the bare battery cell 1 can be 22 mm, 25 mm, 28 mm, 30 mm, 35 mm, 40 mm, 45 mm or 45.2 mm. Of course, the present invention does not limit this, and the value of the diameter R2 of the bare battery cell 1 can be reasonably selected according to actual needs to fully ensure the energy storage effect of the battery 100.

[0090] In some embodiments, referring to Figure 6 , the solder mark 3 has a first end close to the center of the bare battery cell 1 and a second end far from the center of the bare battery cell 1 along the extension reference line. The distance L1 between the first end and the second end satisfies: 6 mm ≤ L1 ≤ 15 mm. For example, the distance L1 between the first end and the second end in the extension reference line direction can be 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm or 15 mm. Of course, the present invention does not limit this, and the value of the distance L1 between the first end and the second end can be reasonably selected according to actual needs. In this way, it can be ensured that the solder mark 3 covers more layers of connecting pieces 1140 in the radial direction to ensure the welding area at the solder mark 3, thereby improving the overcurrent capacity and connection stability.

[0091] In some embodiments, referring to Figure 6 , the distance L2 between the first end and the center of the bare battery cell 1 in the extension reference line direction satisfies: 0 mm ≤ L2 ≤ 10 mm. For example, the distance L2 between the first end and the center of the bare battery cell 1 in the extension reference line direction can be 0 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm or 10 mm. Of course, the present invention does not limit this, and the distance between the first end and the center of the bare battery cell 1 in the extension reference line direction can be reasonably selected according to actual needs. In this way, the first end can be made as close as possible to the center of the bare battery cell 1, so as to extend the width of the solder mark 3 in the reference direction, so that the electrode adapter 2 is welded to more connecting pieces 1140 in the radial direction, ensuring the welding area and improving the overcurrent capacity.

[0092] In some embodiments, referring to Figure 6, the maximum distance L3 between the second end and the edge of the bare battery cell 1 in the direction of the extension reference line satisfies: 0 mm ≤ L3 ≤ 10 mm. For example, the distance L2 between the second end and the edge of the bare battery cell 1 in the direction of the extension reference line can be 0 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm or 10 mm. Of course, the present invention does not limit this, and the distance between the second end and the edge of the bare battery cell 1 in the direction of the extension reference line can be reasonably selected according to actual needs. In this way, the second end can be made as close as possible to the edge of the bare battery cell 1, so as to extend the width of the welding mark 3 in the reference direction, so that the electrode adapter 2 is welded to more connecting pieces 1140 in the radial direction, ensuring the welding area and improving the current-carrying capacity.

[0093] In some embodiments, referring to Figure 4 , there are multiple welding marks 3, and the extension reference line N of each welding mark 3 extends along the radial direction of the bare battery cell 1, and the multiple welding marks 3 are arranged at intervals in the circumferential direction of the bare battery cell 1. At this time, the extension lines of the multiple welding marks 3 can intersect at the center of the bare battery cell 1. In this way, the distribution of the welding marks 3 in the circumferential direction of the bare battery cell 1 can be made relatively uniform to ensure that the current-carrying capacity at each point in the circumferential direction is relatively uniform. At the same time, the arrangement method is simple and easy to implement.

[0094] In other embodiments, referring to Figure 5 and Figure 6 , there are multiple welding marks 3, and the multiple welding marks 3 are divided into several welding groups 4. The several welding groups 4 are arranged at intervals in the circumferential direction of the bare battery cell 1. Each welding group 4 includes several welding marks 3 that are parallel and spaced from each other. And, in each welding group 4, the extension reference line N of one of the welding marks 3 extends along the radial direction of the bare battery cell 1, and the distance L4 between two adjacent welding marks 3 belonging to the same welding group 4 satisfies: 0.5 mm ≤ L4 ≤ 5 mm. For example, the distance L4 between two adjacent welding marks 3 belonging to the same welding group 4 can be 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm or 5 mm. Of course, the present invention does not limit this, and the distance between two adjacent welding marks 3 belonging to the same welding group 4 can be reasonably selected according to actual needs. In this way, it is possible to avoid the problem of concentrated welding energy generated between two adjacent welding marks 3 when the distance between two adjacent welding marks 3 is too close, for example, less than 0.5 mm; and it also avoids the problem that the distribution density of the welding marks 3 is small when the distance between two adjacent welding marks 3 is too far, for example, greater than 5 mm, which affects the current-carrying capacity between the tab 114 and the electrode adapter 2.

[0095] In some embodiments, referring to Figure 3, at one end of the bare battery cell 1 along the winding axis (for example, the negative electrode end of the bare battery cell 1), the end of the separator 113 extends beyond the end of the positive electrode plate 111, and the end of the negative electrode plate 112 extends beyond the end of the separator 113. Among them, the part of the negative electrode plate 112 that extends beyond the separator 113 includes a tab 114, and the tab 114 includes a plurality of independently bendable connecting pieces 1140. And, the plurality of connecting pieces 1140 of the separator are all bent towards the center of the bare battery cell 1, and the plurality of bent connecting pieces 1140 form a tab end face 1141. Among two adjacent connecting pieces 1140 in the radial direction, the connecting piece 1140 closer to the outside can overlap the connecting piece 1140 closer to the inside to ensure that two adjacent connecting pieces 1140 in the radial direction can be connected, so as to achieve current passing.

[0096] The value range of the distance D between the tab end face 1141 and the separator 113 in the axial direction of the bare battery cell 1 is: 1 mm ≤ D ≤ 2 mm. For example, D can be 1 mm, 1.2 mm, 1.4 mm, 1.6 mm, 1.8 mm, 2 mm. If the value of D is less than 1 mm, it will cause the distance between the tab end face 1141 and the welding part of the electrode adapter 2 to be too close to the separator 113, and the heat generated by welding is likely to cause the separator 113 to shrink, resulting in contact between the positive electrode plate 111 and the negative electrode plate 112, which is an internal short circuit. If D is greater than 2 mm, the area of the negative electrode active coating 1122 will be relatively reduced, reducing the energy density of the battery 100. Controlling D within the range of 1 mm ≤ D ≤ 2 mm can cooperate with the welding method of the present application to improve the welding yield and keep the battery 100 having a high energy density.

[0097] In some embodiments, the tab 114 is a copper tab 114, and the electrode adapter 2 is a copper sheet. Since copper has a stronger heat conduction and heat absorption ability, greater sensitivity to high temperature, and greater negative electrode heat influence; in addition, when the copper negative electrode tab 114 is welded, it is easy to be crushed, so it is closer to the separator 113 under the same pressure. Therefore, adopting the welding mark scheme of this embodiment can avoid problems such as welding explosion points, poor welding, and damage to the separator when the copper tab 114 and the electrode adapter 2 are welded.

[0098] The following provides a table of the morphology of the welding mark and the damage detection results of the bare battery cell when the inventor of the present application welds the tab 114 and the electrode adapter 2 to form welding marks of different sizes.

[0099] Table 1 Table of Welding Mark Morphology and Damage Detection Results of Bare Battery Cell

[0100]

[0101] Through the analysis of the above table and in combination with Examples 1-4, it can be seen that when the radius of curvature of the welding mark 3 is less than 0.5 mm, welding explosion points caused by concentrated welding energy are likely to appear in the peripheral area of the welding mark 3, which will cause damage to the separator of the bare battery cell 1. In combination with Examples 5-6, 8-9, and 11-16, when the radius of curvature of the welding mark 3 is greater than or equal to 0.5 mm, welding explosion points caused by concentrated welding energy in the peripheral area of the welding mark can be avoided, thereby avoiding damage to the separator 113 of the bare battery cell 1;

[0102] In combination with Examples 5-16, it can be concluded that the radius of curvature R at the point with the minimum radius of curvature on the welding mark 3 min and the width w of the welding mark satisfy: 2R min - w ≥ 0.5 mm, the morphology of the welding mark 3 is good, and the phenomenon of scalding the separator 113 will not occur. Through analysis, it can be considered that when the above relationship is satisfied, the overlapping of the mutual heat-affected zones between the welding marks 3 on both sides of the point with the minimum radius of curvature is small, and the phenomenon of scalding the separator 113 caused by secondary welding will not occur.

[0103] In summary, it can be seen that for the battery 100 of the present application, by adjusting the radius of curvature of any point on the welding mark 3 between the bare battery cell 1 and the electrode adapter 2 to be greater than or equal to 0.5 mm, the concentration of welding energy and the resulting welding explosion point problem can be avoided, thereby ensuring the welding quality and improving the product qualification rate of the battery 100.

[0104] Next, the electronic device according to the third aspect embodiment of the present invention will be described.

[0105] The electronic device of this embodiment includes: the battery 100 in the above embodiment.

[0106] According to the electronic device of the embodiment of the present invention, by providing the battery 100 in the above embodiment, the battery 100 can supply power to the electronic device more reliably, which is beneficial to improving the user experience.

[0107] It should be noted that "one embodiment", "embodiment", "exemplary embodiment", "some embodiments", etc. mentioned in the specification indicate that the embodiments may include specific features, structures or characteristics, but not necessarily every embodiment includes such specific features, structures or characteristics. In addition, such phrases do not necessarily refer to the same embodiment. Moreover, when combining an embodiment to describe a specific feature, structure or characteristic, it is within the knowledge scope of those skilled in the art to implement such a feature, structure or characteristic in combination with other embodiments, whether explicitly or implicitly described.

[0108] Generally, terms should be understood at least in part in light of their use in context. For example, at least in part depending on the context, the term "one or more" as used herein can be used to describe any feature, structure, or characteristic in the sense of a singular meaning, or can be used to describe a combination of features, structures, or characteristics in the sense of a plural meaning. Similarly, at least in part depending on the context, terms such as "a" or "the" can also be understood to convey a singular usage or a plural usage.

[0109] It should be readily understood that the terms "on", "above", and "over" in this disclosure should be construed in the broadest manner such that "on" not only means "directly on something", but also includes the meaning of "on something" with intervening features or layers therebetween, and "above" or "over" not only includes the meaning of "above" or "over something", but can also include the meaning of "above" or "over something" with no intervening features or layers therebetween (i.e., directly on something).

[0110] In addition, spatial relative terms may be used herein for ease of description, such as "below", "beneath", "under", "above", "over", etc., to describe the relationship of one element or feature to another as shown in the figures. Spatial relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation shown in the figures. The device may have other orientations (rotated 90 degrees or at other orientations), and the spatial relative descriptors used herein can be interpreted accordingly.

[0111] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and are not intended to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A battery, characterized in that: Comprising: A housing assembly; A bare battery cell, disposed within the housing assembly, the bare battery cell comprising: a positive electrode sheet, a negative electrode sheet, and a separator, the positive electrode sheet, the separator, and the negative electrode sheet being sequentially stacked and wound around a winding axis, and an electrode tab being provided at one end of the bare battery cell along the winding axis; An electrode transfer sheet, welded to the electrode tab and forming at least one continuous weld mark, at least a part of the weld mark extending from the outer periphery of the bare battery cell towards the inner periphery, the weld mark including an arc segment; The radius of curvature R at any point of the weld mark is greater than or equal to 0.5 mm.

2. The battery according to claim 1, characterized in that The weld mark has an extension reference line, and the extension reference line divides the weld mark into a plurality of welding segments arranged in sequence along the extension direction of the extension reference line, and any two adjacent welding segments are respectively located on opposite sides of the extension reference line.

3. The battery according to claim 2, characterized in that The extension reference line is a straight line.

4. The battery according to claim 3, characterized in that Among the plurality of welding segments, at least the welding segments other than those located at both ends of the weld mark have transition points; The distance from the transition point to the extension reference line is greater than the distance from any point on both sides of the transition point to the extension reference line; And, the transition point is located on the arc segment.

5. The battery according to claim 4, characterized in that The distances from the transition points of any two welding segments to the extension reference line are equal.

6. The battery according to claim 5, characterized in that Any two adjacent welding segments are centrosymmetric about the connection point of the two welding segments.

7. The battery according to claim 3, characterized in that The welding segment is arc-shaped; or, the welding segment includes an arc segment and non-arc segments located on both sides of the arc segment.

8. The battery according to claim 7, characterized in that When the welding segment is arc-shaped, the welding segment is a part of a circle.

9. The battery according to claim 5, characterized in that The height-span ratio A of the welding segment satisfies: 0 < A < 3, where A = H / L, H is the distance between the transition point and the extension reference line, and L is the length of the line connecting the two ends of the welding segment.

10. The battery according to claim 9, characterized in that The height-span ratio A of the welding segment satisfies: 0.25 ≤ A ≤ 1.

11. The battery according to claim 1, characterized in that The width w of the weld mark ranges from 0.2 mm to 0.8 mm.

12. The battery according to claim 11, characterized in that The radius of curvature R at the minimum point of the weld mark min Satisfies: 2R min -w≥0.5mm.

13. The battery according to claim 3, characterized in that The weld mark has a first end close to the center of the bare battery cell and a second end far from the center of the bare battery cell along the extension reference line, and the distance L1 between the first end and the second end satisfies: 6 mm ≤ L1 ≤ 15 mm; and / or, The distance L2 between the first end and the center of the bare battery cell in the direction of the extension reference line satisfies: 0 mm ≤ L2 ≤ 10 mm; and / or, The maximum distance L3 between the second end and the edge of the bare battery cell in the direction of the extension reference line satisfies: 0 mm ≤ L3 ≤ 10 mm.

14. The battery according to claim 3, characterized in that There are a plurality of weld marks, the extension reference lines of each weld mark extend along the radial direction of the bare battery cell, and the plurality of weld marks are arranged at intervals along the circumferential direction of the bare battery cell.

15. The battery according to claim 3, characterized in that There are a plurality of weld marks, and the plurality of weld marks are divided into several welding groups, and the several welding groups are arranged at intervals along the circumferential direction of the bare battery cell; Each welding group includes several weld marks arranged in parallel and at intervals, and, among them, the extension reference line of one of the weld marks in each welding group extends along the radial direction of the bare battery cell; The distance L4 between two adjacent weld marks belonging to the same welding group satisfies: 0.5 mm ≤ L4 ≤ 5 mm.

16. The battery according to any one of claims 1 to 15, characterized in that At one end of the bare cell along the winding axis, the end of the diaphragm exceeds the end of the positive electrode sheet, and the end of the negative electrode sheet exceeds the end of the diaphragm, and the portion of the negative electrode sheet that exceeds the diaphragm includes the pole ear, and the pole ear includes a plurality of independently bendable connecting sheets, and the plurality of connecting sheets are bent toward the center of the bare cell, and the bent plurality of connecting sheets form a pole ear end face, The value range of the distance D between the end surface of the pole tab and the diaphragm in the axial direction of the bare battery core is: 1mm≤D≤2mm.

17. The battery according to any one of claims 1 to 15, characterized in that The electrode tab is a copper electrode tab, and the electrode adapter sheet is a copper sheet.

18. An electronic device, characterized in that: include: The battery according to any one of claims 1 to 17.

Images