Battery and electronic device

Abstract

To provide a battery and an electronic apparatus capable of securing welding quality.SOLUTION: The battery includes a housing assembly, a bare cell disposed in the housing assembly and including a positive electrode plate, a negative electrode plate, and a separator, wherein the positive electrode plate, the negative electrode plate, and the separator are sequentially stacked and wound around a winding axis, and one end of the bare cell along the winding axis is provided with a tab, and an electrode adapter welded to the tab to form at least one continuous welding mark, wherein at least a part of the welding mark extends from an outer periphery to an inner periphery of the bare cell, the welding mark includes an arc segment, and a curvature radius of any portion of the welding mark is greater than or equal to 0.5 mm.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to the technical field of batteries, and in particular to batteries and electronic devices. [Background technology]

[0002] With the development of society and economy, more and more electrical devices, such as new energy vehicles, communication base stations, energy storage containers, etc., are adopting batteries as energy storage and supply devices. A battery usually includes an internal bare cell and a housing assembly, and the tabs of the bare cell are connected to the electrode output terminals on the battery via an electrode adapter to achieve electrical continuity.

[0003] Currently, some battery models use wire welding to weld the tabs and electrode adapters. A wavy welding path is used to increase the welding area. The sudden change in the radius of curvature at the transition point on the welding path causes welding heat to concentrate in the transition point area. The generated welding heat can accumulate and penetrate the tab, causing the active material inside the battery to burn. Summary of the Invention [Problem to be solved by the invention]

[0004] In view of the above problems, the present invention provides a battery and an electronic device in which the radius of curvature R at any part of the weld mark is 0.5 mm or more, thereby preventing the problem of welding heat concentration and the associated welding explosion points, ensuring welding quality, and improving the product acceptance rate. [Means for solving the problem]

[0005] The present invention provides a battery including: a housing assembly; a bare cell provided within the housing assembly and including a positive electrode sheet, a negative electrode sheet, and a separator, wherein the positive electrode sheet, the separator, and the negative electrode sheet are stacked in that order and wound around a winding axis, with a tab provided at one end along the winding axis; and an electrode adapter welded to the tab to form at least one continuous weld mark, at least a portion of which extends from the outer periphery to the inner periphery of the bare cell, and the weld mark includes a circular arc segment, wherein the radius of curvature at any part of the weld mark is 0.5 mm or greater.

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

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

[0008] In some embodiments, among the plurality of weld segments, all of the remaining weld segments except for at least those located at both ends of the weld mark have a transition point, the distance between the transition point and the extended reference line is greater than the distance between any point on either side of the transition point and the extended reference line, and further, the transition point is located on a circular arc segment.

[0009] In some embodiments, the distance from the transition point of any two weld segments to the extended reference line is equal.

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

[0011] In some embodiments, the weld segment is arc-shaped, or the weld segment includes an arc segment and non-arc segments located on either side of the arc segment.

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

[0013] In some embodiments, the span-depth 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 both ends of the welding segment, and L is the length of the line connecting the ends of the welding segment.

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

[0015] In some embodiments, the value range of the width w of the weld bead is 0.2 mm to 0.8 mm.

[0016] In some embodiments, at the minimum point of the radius of curvature on the weld bead, the radius of curvature R is 2R min - w ≥ 0.5 mm is satisfied.

[0017] In some embodiments, the weld bead has a first end close to the center of the bare cell and a second end far from the center of the bare cell along the extension reference line. The distance L1 between the first end and the second end satisfies 6 mm ≤ L1 ≤ 十五 mm; and / or, the distance L2 between the first end and the center of the bare cell in the direction of the extension reference line satisfies 0 mm ≤ L2 ≤ 十 mm; and / or, the maximum distance L3 between the second end and the edge of the bare cell in the direction of the extension reference line satisfies 0 mm ≤ L3 ≤ 十 mm.

[0018] In some embodiments, there are multiple weld beads. The extension reference lines of each weld bead extend along the radial direction of the bare cell, and the multiple weld beads are provided at intervals along the circumferential direction of the bare cell.

[0019] In some embodiments, there are multiple weld marks, and the multiple weld marks are divided into several weld groups, and the several weld groups are spaced apart along the circumferential direction of the bare cell, and each weld group includes several parallel weld marks that are spaced apart from each other, and further, the extension reference line of one weld mark in each weld group extends along the radial direction of the bare cell, and the spacing distance L4 between two adjacent weld marks belonging to the same weld group satisfies 0.5 mm≦L4≦5 mm.

[0020] In some embodiments, at one end of the bare 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 portion of the negative electrode sheet extending beyond the separator includes a tab, and the tab includes a plurality of independently foldable connecting sheets, each of which is folded toward the center of the bare cell, and the folded connecting sheets form a tab end surface, and the value of the gap D between the tab end surface and the separator in the axial direction of the bare cell is in the range of 1 mm≦D≦2 mm.

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

[0022] A second aspect of the present invention provides an electronic device including the battery according to the first aspect of the present invention. [Effects of the Invention]

[0023] In the battery of the present invention, the weld marks on the tabs and electrode adapters of the bare cell comprise arc segments, and the radius of curvature R at any point on the weld marks is 0.5 mm or more, thereby increasing the distance between the portions on both sides of the transition point of the arc segments and preventing overlapping of the heat-affected zones on both sides of the transition point, preventing the concentration of welding heat and the resulting problem of welding explosion points, and thus preventing the welding heat from penetrating the tabs and burning the active material and separator inside the bare cell, ensuring welding quality, improving the product pass rate, and being advantageous for large-scale production and application. [Brief explanation of the drawings]

[0024] In order to more clearly describe the embodiments of the present invention or the technical solutions in the prior art, the drawings necessary for use in the description of the embodiments or the prior art are briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technical personnel in this field, other drawings can be obtained based on these drawings without any creative work.

[0025] [Figure 1] 1 is a structural schematic diagram of a battery in some embodiments of the present invention. [Figure 2] FIG. 2 is a cross-sectional view taken along the line AA in FIG. [Figure 3] 1 is a structural schematic diagram of a bare cell in some embodiments of the present invention. FIG. [Figure 4] FIG. 2 is a schematic diagram showing the distribution of welding marks in a battery according to some embodiments of the present invention. [Figure 5] 10A to 10C are schematic diagrams showing distributions of welding marks in batteries according to some other embodiments of the present invention. [Figure 6] 1 is a structural schematic diagram of a weld mark of a battery in some embodiments of the present invention. FIG. [Figure 7] 1 is a structural schematic diagram of a weld mark in some embodiments of the present invention. [Figure 8] 1 is a structural schematic diagram of a weld mark in some embodiments of the present invention. [Figure 9] 1 is a structural schematic diagram of a weld mark in some embodiments of the present invention. [Figure 10] 1 is a structural schematic diagram of a weld mark in some embodiments of the present invention. [Figure 11] 1 is a structural schematic diagram of a weld mark in some embodiments of the present invention. [Figure 12] 1 is a structural schematic diagram of a weld mark in some embodiments of the present invention. [Figure 13] 3A to 3C are schematic diagrams illustrating a process for forming a welding mark in an embodiment of the present invention. [Figure 14]This is a welding effect diagram when the height-to-span ratio of the weld mark is 0.25. [Figure 15] This is a diagram of the welding effect when the height-to-span ratio of the weld mark is 0.5. [Figure 16] This is a welding effect diagram when the height-to-span ratio of the weld mark is 1. [Figure 17] This is a welding effect diagram when the height-to-span ratio of the weld mark is 2. [Figure 18] This is a diagram of the welding effect when the height-to-span ratio of the weld mark is 3. DETAILED DESCRIPTION OF THE INVENTION

[0026] In order to make the above-mentioned objectives, features and advantages of the embodiments of the present invention clearer and easier to understand, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings of the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments, not all of the embodiments of the present invention. All other embodiments obtained by ordinary skilled in the art based on the embodiments of the present invention without creative work shall fall within the scope of protection of the present invention.

[0027] With the development of society and the economy, more and more electrical appliances are adopting batteries as energy storage and supply devices. Electronic devices may be vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, power tools, etc. Vehicles may be fuel-powered vehicles, gas-powered vehicles, or new energy vehicles. New energy vehicles may be pure electric vehicles, hybrid vehicles, long-distance vehicles, etc. Spacecraft may be airplanes, rockets, space shuttles, spaceships, etc. Electric toys include stationary or mobile electric toys such as game consoles, electric car toys, electric boat toys, and electric airplane toys. Power tools include metal cutting tools, grinding tools, assembly tools, and railroad tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers. Electronic devices may also be battery packs, battery modules, etc. The embodiments of the present invention are not particularly limited to the above electronic devices.

[0028] The electronic device may include a device body and a battery. The device body may include a battery compartment. The battery is provided in the battery compartment and electrically connected to the device body. For example, a power interface may be provided in the battery compartment, and the battery may be connected to the power interface.

[0029] In an embodiment of the present invention, the battery may be a primary battery or a secondary battery. A primary battery refers to a battery that cannot be recharged after discharge, while a secondary battery refers to a battery that can be reused by recharging after discharge to reactivate the active material. The battery may 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, or the like, but the embodiment of the present application is not limited thereto.

[0030] Currently, some battery models use wire welding between the tab and the electrode adapter. To increase the welding area, a wavy welding path is used. However, due to the sudden change in the curvature radius in some areas of the welding path, the welding heat is concentrated in the corresponding area, and the generated welding heat accumulates and penetrates the tab, causing the active material inside the battery to burn.

[0031] In view of this, the present embodiment provides a battery and electronic device. The radius of curvature R at any point on the weld mark is 0.5 mm or greater. Increasing the distance between any two points on the weld path prevents the heat-affected zones of adjacent welds from overlapping, preventing the concentration of welding heat and the associated problem of welding explosions. This prevents the welding heat from penetrating the tab and burning the active material and separator inside the bare cell. This ensures welding quality and improves the product pass rate, which is advantageous for large-scale production and application. Furthermore, the radius of curvature R in this invention refers to the radius of curvature of the line obtained by connecting the midpoints of the weld marks in the width direction.

[0032] 1 to 18, the battery 100 of this embodiment includes a housing assembly 5, a bare cell 1, and an electrode adapter 2.

[0033] 1 and 2, the housing assembly 5 may include a shell 51 and a cover plate 52. An opening is provided at one end of the shell 51. The inner cavity of the shell 51 functions as a receiving cavity for the bare cell 1. The shell 51 includes a top wall 511 facing the cover plate 52 and a side wall 512 surrounding the top wall 511. The top wall 511 and the side wall 512 may be formed integrally or may be separate structures. The cover plate 52 may cover the opening of the shell 51.

[0034] The battery 100 may further include a positive current collector 6 and a terminal 7. The terminal 7 is inserted through the upper wall 511 and is connected to the positive current collector 6 by welding. The terminal 7 functions as a positive output terminal of the battery 100.

[0035] 3, the bare cell 1 may be provided in the receiving cavity, and may include a positive electrode sheet 111, a negative electrode sheet 112, and a separator 113. Here, the positive electrode sheet 111 includes a positive electrode current collector 1111 and a positive electrode active coating layer 1112 applied to 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 layer 1122 applied to the surface of the negative electrode current collector 1121. For example, if the battery 100 is a cylindrical battery, the positive electrode sheet 111, the separator 113, and the negative electrode sheet 112 are stacked in this order and wound to form the wound type bare cell 1.

[0036] The bare cell 1 may be provided with a tab 114 at one end along the winding axis. The tab 114 may be a negative electrode tab of the bare cell 1. The bare cell 1 is provided with a positive electrode tab 1113 at one end facing the upper wall 511, and electrical connection is established between the positive electrode tab 1113 and the terminal 7 via the positive electrode current collector plate 6.

[0037] The tab 114 may include multiple connecting sheets 1140, that is, multiple connecting sheets 1140 may collectively constitute the tab 114. Here, each connecting sheet 1140 is a blank foil area extending from the main body of the bare cell 1 and not coated with a fluid-collecting active coating layer, and at least some of the multiple connecting sheets 1140 are distributed along the circumferential direction of the bare cell 1. For example, multiple connecting sheets 1140 may be simultaneously arranged in an array along the circumferential direction and radial direction of the bare cell 1.

[0038] When the positive electrode sheet 111, separator 113, and negative electrode sheet 112 are stacked and then wound, the negative electrode side of the bare cell 1 has the negative electrode current collector 1121 extending beyond a portion of the negative electrode active coating layer 1122. This means that the blank foil region of the negative electrode current collector 1121 is a continuous surface, which can result in numerous wrinkles when flattened. In contrast, the multiple connection sheets 1140 of this embodiment divide the blank foil region into multiple segments, thereby reducing the length of each connection sheet 1140 in the circumferential direction of the bare cell 1. This reduces the occurrence of wrinkles when the connection sheets 1140 are folded and stacked on top of each other, and can further flatten the tab end surface 1141 formed by folding the multiple connection sheets 1140. The tab end surface 1141 is the surface at one end of the bare cell 1 after the multiple connection sheets 1140 are folded and stacked, and it can be seen that this contributes to improving the welding efficiency between the tab 114 and the electrode adapter 2. Correspondingly, on the positive electrode side of the bare cell 1, the blank foil area of ​​the positive electrode current collector 1111 can also be divided into a plurality of connection sheets.

[0039] 1 to 3, the electrode adapter 2 may be a copper sheet for welding to the copper foil of the tab 114. The electrode adapter 2 is welded to the tab 114, forming at least one continuous weld mark 3. A continuous weld mark 3 means that there are no interruptions in the single weld mark 3. At least a portion of the weld mark 3 extends from the outer periphery to the inner periphery of the bare cell 1. When the positive electrode sheet 111, separator 113, and negative electrode sheet 112 are wound around a winding needle to form the bare cell 1, a central hole is formed at the radial center of the bare cell 1 itself. A cross section perpendicular to the central axis of the bare cell 1 exhibits a circular ring shape, with the outer periphery of the bare cell 1 being located at the outer contour of the ring and the inner periphery being located at the inner contour of the ring. In this way, when the electrode adapter 2 is welded to the tab 114, the electrode adapter 2 is welded to at least a portion of the multiple connection sheets 1140, forming the weld mark 3. Furthermore, since at least a portion of the weld marks 3 extend radially, it is possible to connect as many layers of tabs 114 as possible to the electrode adapter 2, increase the connection area, and reduce the internal resistance of the battery 100. Here, the welding method may be laser welding, ultrasonic welding, or other welding methods. Optionally, the electrode adapter 2 may further be connected to a shell 51, which may function as a negative output terminal of the battery 100.

[0040] Combining Figures 4 to 12, the weld mark 3 includes arc segments 32. Furthermore, the radius of curvature at any portion of the weld mark 3 is 0.5 mm or more. For example, the weld mark 3 may be composed only of arc segments 32. In this case, the radius of curvature at any portion on each arc segment 32 is 0.5 mm or more. Alternatively, the weld mark 3 may be composed of arc segments 32 and straight line segments. In this case, the radius of curvature at any portion on the arc segments 32 is 0.5 mm or more, and the radius of curvature of the straight line segments is infinite; that is, the radius of curvature of the straight line segments satisfies the requirement of 0.5 mm or more. In this way, the radius of curvature at any portion of the weld mark 3 can be made 0.5 mm or more.

[0041] If the weld mark 3 includes an arc segment 32, the welding movement speed of the welding device 200 (e.g., the welding head of the laser welding device 200) decreases during the welding process at the point where the radius of curvature of the arc segment 32 is smallest (i.e., the transition point G below). Because the portions on both sides of the transition point G are close to each other, any portion on one side of the transition point G is located within the heat-affected zone of another side, meaning that the heat-affected zones on both sides of the transition point G overlap. As a result, as shown in FIGS. 16 to 18 , welding heat concentrates at the transition point G and the area surrounding the transition point G, resulting in the problem of a weld explosion point. To avoid the concentration of welding heat at the transition point G, in this embodiment, the radius of curvature at any portion of the weld mark 3 is set to 0.5 mm or more. Naturally, the specific value of the radius of curvature at each point of the weld mark 3 can be appropriately selected as needed. By having the radius of curvature satisfy the above range, the transition angle at least of the arc segment 32 at the transition point G becomes small, and the distance between the portions on both sides of the transition point G becomes large. This makes it possible to prevent the heat affected zones on both sides of the transition point G from overlapping as shown in FIGS. 14 and 15, and also to avoid the problem of welding heat concentration.

[0042] In the battery 100 according to the present embodiment, the weld mark 3 between the tab 114 of the bare 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. This increases the distance between the portions on either side of the point of the minimum radius of curvature of the arc segment 32, preventing overlapping of the heat-affected zones on either side of the point of the minimum radius of curvature. This prevents the concentration of welding heat and the resulting problem of welding explosion points, preventing the welding heat from penetrating the tab and burning the active material and separator inside the bare cell 1. This ensures welding quality and improves the product pass rate, which is advantageous for large-scale production and application.

[0043] 4 to 12, the weld mark 3 has an extension reference line N. The extension reference line N is a single imaginary reference line that indicates the extension direction of the entire welding trajectory of the weld mark 3. The extension reference line N may be a straight line or a curved line such as a U-shape or a spiral. The extension reference line N divides the weld mark 3 into a plurality of weld segments 31. The plurality of weld segments 31 are sequentially arranged along the extension direction of the extension reference line N, and any two adjacent weld segments 31 are located on opposite sides of the extension reference line N. As a result, all of the remaining weld segments 31, except for at least both ends of the weld mark 3, protrude in a direction away from the extension reference line N. In this case, the weld mark 3 between the tab 114 and the electrode adapter 2 is wavy. The weld mark 3 connects several connection sheets 1140 distributed circumferentially and several connection sheets 1140 distributed radially to the electrode adapter 2, increasing the weld area and improving connection strength, thereby contributing to improved welding reliability.

[0044] 6 to 12, in one specific example, the extension reference line N is a straight line. In this case, the plurality of weld segments 31 may be distributed sequentially along the straight line. This simplifies the structure of the weld mark 3, reduces the difficulty of the welding process compared to a technical solution in which the extension reference line N is a curved line, and contributes to ensuring welding quality.

[0045] 10 to 12, all of the multiple welded segments 31 except for at least both ends of the weld mark 3 have a transition point G. The distance between the transition point G and the extended reference line N is greater than the distance between any point on either side of the transition point G and the extended reference line N. In other words, the transition point G is the point on the welded segment 31 that is farthest from the extended reference line N. Furthermore, at least the portion of the welded segment 31 where the transition point G is located forms the arc segment 32 of the weld mark 3.

[0046] For example, among the multiple welded segments 31 arranged along a straight line, one welded segment 31 closer to the outer periphery of the bare cell 1 is a tip welded segment, and one welded segment 31 closer to the inner periphery of the bare cell 1 is an end welded segment. In this embodiment, as shown in Figure 12, all of the remaining welded segments other than the tip welded segment and the end welded segment have a transition point G, and neither the tip welded segment nor the end welded segment may have a transition point G. Alternatively, as shown in Figures 10 and 11, at least one of the tip welded segment and the end welded segment may have a transition point G.

[0047] Optionally, referring to Figure 11, when the tip weld segment and the end weld segment have a transition point G, the tip weld segment and the end weld segment may have one intersection with the extended reference line N. In this case, only the portions of the tip weld segment and the end weld segment located on one side of the transition point G extend to the extended reference line N, and the portions on the other side of the transition point G do not intersect with the extended reference line N. Alternatively, referring to Figure 10, the tip weld segment and the end weld segment each have two intersections with the extended reference line N, that is, both portions on both sides of the transition point G extend to the extended reference line N.

[0048] Here, the portion of each welded segment 31 where the transition point G is located constitutes the arc segment 32. For example, each welded segment 31 may be formed in an arc shape as a whole. In this case, the welded segment 31 becomes the arc segment 32. Alternatively, the transition point G region of each welded segment 31 may be arc-shaped, and both sides of the transition point G region may have other shapes. In this case, only the portion of the welded segment 31 where the transition point G is located constitutes the arc segment 32.

[0049] In some embodiments, the distances from the transition points G of any two weld segments 31 to the extended reference line N are equal. In other words, the extended reference line N is located at the center of the height of the weld mark 3 itself.

[0050] In some embodiments, referring to FIGS. 4 to 6 and 10 , any two adjacent welded segments 31 are symmetrical with respect to the connection point between the two welded segments 31. "Symmetrical" here refers to the fact that one of the two adjacent welded segments 31 rotates 180° around the connection point between the two and then overlaps with the other. In this case, the openings of any two adjacent welded segments 31 are in opposite directions. This results in a wave-shaped weld mark 3 formed as a whole, consisting of multiple welded segments 31. That is, the welding trajectory of the electrode adapter 2 and multiple tabs 114 is wave-shaped. Because the weld mark 3 does not extend in a straight line but has a certain span in the circumferential direction of the bare cell 1, each welded segment 31 of the weld mark 3 can be connected to several connection sheets 1140 distributed in the circumferential direction. At the same time, the entire weld mark 3 can also be connected to several connection sheets 1140 distributed along the radial direction. This increases the connection area between the electrode adapter 2 and the tabs 114, improves welding strength, shortens the current transmission path, and reduces the internal resistance of the battery 100.

[0051] In some embodiments, combining Figures 7 to 9, the welded segment 31 may be arc-shaped. For example, the welded segment 31 may be arc-shaped or non-arc-shaped. In this case, the overall shape of the welded mark 3 approximates a sinusoidal trajectory. Alternatively, the welded segment 31 includes an arc-shaped segment 32 and non-arc-shaped segments 32 located on both sides of the arc-shaped segment 32. The non-arc-shaped segments 32 may be straight segments or have other shapes. This ensures that each welded segment 31 of the welded mark 3 has a constant span in the circumferential direction and connects multiple connecting sheets 1140 distributed along the circumferential direction. Furthermore, the shape of the welded mark 3 is more diverse, and the structure is relatively simple, making it easy to implement.

[0052] Preferably, the welding segment 31 is formed as a part of a circle. Specifically, it may be semi-circular, and can smooth the transition at the transition point G of the weld mark 3. Further, since the radius of curvature at each point of the weld mark 3 is the same, the smooth movement of the laser welding device becomes easier, the welding quality at each point is good, the welding depth is uniform, and problems such as energy accumulation and occurrence of explosion points can be more effectively avoided. Further, by using a semi-circular locus, a plurality of tabs 114 connected in the weld mark can be welded, thereby improving the quality reliability. When the welding segment 31 is semi-circular, in order to sufficiently prevent problems such as energy accumulation and occurrence of explosion points at the transition point G of the weld mark 3, the diameter of the welding segment 31 is preferably 1 mm to 2 mm.

[0053] In some embodiments, referring to FIG. 7, the span depth ratio A of the welding segment 31 satisfies 0 < A < 3. Specifically, the height to span ratio A = H / L of the welding segment 31. Here, H is the distance between the transition point G of the welding segment 31 and the line connecting both ends of the welding segment 31, that is, the height of the welding segment 31. L is the length of the line connecting the ends of the welding segment 31, that is, the span of the welding segment 31. Here, the value of H affects the span of the welding segment 31 in the circumferential direction of the bare cell 1, thereby affecting the welding area of the electrode adapter 2 and the tab 114 in the circumferential direction, and the overcurrent resistance in the weld mark 3. L affects the size of the corner in the welding segment 31.

[0054] For example, the height to span ratio of the welding segment 31 may be 0.5, 1, 1.5, 2, 2.5, etc., but of course, the present invention is not limited thereto. In this way, the height of the welding segment 31 in the circumferential direction of the bare cell 1 can be ensured to be relatively high, thereby increasing the number of connection sheets 1140 covered by the welding segment 31 in the circumferential direction, increasing the welding area, improving the overcurrent resistance, further improving the smoothness of the transition point G of the welding segment 31, and avoiding the concentration of welding heat.

[0055] Furthermore, the height-to-span ratio A of the welded segment 31 satisfies 0.25≦A≦1. For example, the height-to-span ratio of the welded segment 31 may be 0.25, 0.5, 0.6, 0.7, 0.8, 0.9, etc., but the present invention is not limited to this. In this way, the weld area of ​​the welded segment 31 is secured, while the smoothness of the welded segment 31 at the transition point G is further improved, welding heat concentration is avoided, and welding quality is improved.

[0056] Please refer to Figures 14 to 18. Here, Figure 14 shows the welding effect at the transition point G of the welded segment 31 when the height-to-span ratio of the welded segment 31 is 0.25. Figure 15 shows the welding effect at the transition point G of the welded segment 31 when the height-to-span ratio of the welded segment 31 is 0.5. Figure 16 shows the welding effect at the transition point G of the welded segment 31 when the height-to-span ratio of the welded segment 31 is 1. Figure 17 shows the welding effect at the transition point G of the welded segment 31 when the height-to-span ratio of the welded segment 31 is 2. Figure 18 shows the welding effect at the transition point G of the welded segment 31 when the height-to-span ratio of the welded segment 31 is 3. 14 to 18, when the height-to-span ratio is 3, the transition angle at the transition point G of the welding segment 31 is excessively large and the distance between the portions on both sides of the transition point G is short. This results in a large effect of the welding heat on the area surrounding the transition point G, resulting in a dark area caused by the concentration of the welding heat. This area is detrimental to the quality of the weld between the tab 114 and the electrode adapter 2. On the other hand, when the height-to-span ratio is 2, the area surrounding the transition point G of the welding segment 31 is only slightly affected by the welding heat, improving the quality of the weld between the tab 114 and the electrode adapter 2. On the other hand, when the height-to-span ratio is 0.25, 0.5, or 1, the problem of welding heat concentration in the area surrounding the transition point G of the welding segment 31 is minimal and is essentially unaffected by the concentration of welding heat, ensuring reliable welding quality between the tab 114 and the electrode adapter 2.

[0057] In some embodiments, the width w of the weld mark 3 ranges from 0.2 mm to 0.8 mm. That is, the width w of each welded segment 31 perpendicular to the extension direction ranges from 0.2 mm to 0.8 mm. For example, the width w of the weld mark 3 may be 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, or 0.8 mm, but the present invention is not limited thereto. In this way, it is possible to avoid a decrease in welding reliability due to an excessively small weld area, which would occur if the width of the weld mark 3 were too small, e.g., less than 0.2 mm. Because a high resistance value at the weld mark 3 affects overcurrent resistance, an excessively large width at the weld mark 3, e.g., greater than 0.8 mm, can prevent the heat-affected zones on both sides of the transition point G of the welded segment 31 from overlapping, resulting in welding heat concentration. In summary, the weld area at the weld mark 3 is sufficiently large, thereby ensuring overcurrent resistance and minimizing the occurrence of welding heat concentration, which would affect welding quality.

[0058] 13, when laser welding is employed, the closer the welding focal point B is to the welding surface (i.e., the surface of the electrode adapter 2), the more concentrated the welding heat becomes, making it more likely that problems with welding explosion points will occur. On the other hand, the farther the welding focal point B is from the welding surface, the more the welding heat disperses, penetrating the electrode adapter 2 and reaching the tab 114, making it less likely that false welding or pseudo welding will occur. Therefore, in this embodiment, by maintaining an appropriate distance between the welding focal point B and the welding surface, the width of the welding mark 3 can be maintained at 0.2 mm to 0.8 mm. In this way, problems with welding explosion points due to the concentration of welding heat can be prevented, the connection strength between the electrode adapter 2 and the tab 114 can be ensured, and both workability and reliability are improved.

[0059] 6, in some embodiments, the value range of the diameter R2 of the bare cell 1 may be 22 mm≦R2≦45.2 mm. For example, the diameter R2 of the bare cell 1 may be 22 mm, 25 mm, 28 mm, 30 mm, 35 mm, 40 mm, 45 mm, or 45.2 mm, but the present invention is not limited thereto. The value of the diameter R2 of the bare cell 1 may be appropriately selected according to actual needs to ensure sufficient energy storage effect of the battery 100.

[0060] In some embodiments, referring to FIG. 6 , the weld mark 3 has a first end close to the center of the bare cell 1 along the extension reference line and a second end farther from the center of the bare cell 1. 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 along the extension reference line may be 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, or 15 mm, but the present invention is not limited thereto. The value of the distance L1 between the first end and the second end can be appropriately selected according to actual needs. In this way, the weld mark 3 can cover more layers in the radial direction of the connection sheet 1140, ensuring a larger welding area at the weld mark 3, thereby improving overcurrent resistance and connection stability.

[0061] In some embodiments, referring to FIG. 6 , the distance L2 between the first end and the center of the bare cell 1 in the direction of the reference line satisfies 0 mm≦L2≦10 mm. For example, the distance L2 between the first end and the center of the bare cell 1 in the direction of the reference line may be 0 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, or 10 mm, but the present invention is not limited thereto. The distance between the first end and the center of the bare cell 1 in the direction of the reference line may be appropriately selected according to actual needs. In this way, by bringing the first end as close as possible to the center of the bare cell 1, the width of the weld mark 3 in the reference direction can be increased, and the electrode adapter 2 can be welded to a larger number of connection sheets 1140 in the radial direction, ensuring a larger welding area and improving overcurrent resistance.

[0062] In some embodiments, referring to FIG. 6 , the maximum gap distance L3 between the second end and the edge of the bare cell 1 in the extension reference line direction satisfies 0 mm≦L3≦10 mm. For example, the gap distance L2 between the second end and the edge of the bare cell 1 in the extension reference line direction may be 0 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, or 10 mm, but the present invention is not limited thereto. The gap distance between the second end and the edge of the bare cell 1 in the extension reference line direction can be appropriately selected according to actual needs. In this way, by bringing the second end as close as possible to the edge of the bare cell 1, the width of the weld mark 3 in the reference direction can be increased, allowing the electrode adapter 2 to be welded to more of the connection sheet 1140 in the radial direction, ensuring a larger welding area and improving overcurrent resistance.

[0063] In some embodiments, referring to FIG. 4, there are multiple weld marks 3, and the extension reference line N of each weld mark 3 extends along the radial direction of the bare cell 1, with the multiple weld marks 3 being spaced apart along the circumferential direction of the bare cell 1. In this case, the extension lines of the multiple weld marks 3 can intersect at the center of the bare cell 1. In this way, the distribution of the weld marks 3 around the circumferential direction of the bare cell 1 can be made more uniform, and the overcurrent resistance at each position around the circumferential direction can be made more uniform. At the same time, the arrangement method is simple and easy to implement.

[0064] 5 and 6 , in some other embodiments, there are multiple weld marks 3, and the multiple weld marks 3 are divided into several weld groups 4. The several weld groups 4 are spaced apart along the circumferential direction of the bare cell 1, and each weld group 4 includes several parallel weld marks 3 spaced apart from one another. Furthermore, in each weld group 4, the extension reference line N of one weld mark 3 extends along the radial direction of the bare cell 1, and the spacing distance L4 between two adjacent weld marks 3 belonging to the same weld group 4 satisfies 0.5 mm≦L4≦5 mm. For example, the spacing distance L4 between two adjacent weld marks 3 belonging to the same weld group 4 may 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, but the present invention is not limited thereto. The spacing distance between two adjacent weld marks 3 belonging to the same weld group 4 can be appropriately selected according to actual needs. In this way, it is possible to avoid the problem of welding heat concentration between two adjacent weld marks 3 when the two adjacent weld marks 3 are too close, for example, when the distance between the two adjacent weld marks 3 is 0.5 mm. It is also possible to avoid the effect on the overcurrent resistance between the tab 114 and the electrode adapter 2 due to a decrease in the distribution density of the weld marks 3 when the distance between the two adjacent weld marks 3 is too far, for example, when the distance exceeds 5 mm.

[0065] In some embodiments, referring to FIG. 3 , at one end of the bare cell 1 along the winding axis (e.g., the negative electrode end of the bare cell 1), the end of the separator 113 extends beyond the end of the positive electrode sheet 111, and the end of the negative electrode sheet 112 extends beyond the end of the separator 113. Here, the portion of the negative electrode sheet 112 that extends beyond the separator 113 includes a tab 114. The tab 114 includes a plurality of independently foldable connection sheets 1140. Furthermore, the plurality of connection sheets 1140 of the separator 113 are all folded toward the center of the bare cell 1, and the folded plurality of connection sheets 1140 form tab end surfaces 1141. Of two radially adjacent connection sheets 1140, the connection sheet 1140 closer to the outside overlaps the connection sheet 1140 closer to the inside, thereby ensuring connection between the two radially adjacent connection sheets 1140 and thereby realizing current flow.

[0066] The range of the distance D between the tab end surface 1141 and the separator 113 in the axial direction of the bare cell 1 is 1 mm≦D≦2 mm. For example, D may be 1 mm, 1.2 mm, 1.4 mm, 1.6 mm, 1.8 mm, or 2 mm. If D is less than 1 mm, the welding point between the tab end surface 1141 and the electrode adapter 2 becomes close to the separator 113. This can cause the separator 113 to shrink due to heat generated by welding, potentially causing contact between the positive electrode sheet 111 and the negative electrode sheet 112 and resulting in an internal short circuit. If D exceeds 2 mm, the area of ​​the negative electrode active coating layer 1122 is relatively reduced, resulting in a decrease in the energy density of the battery 100. By controlling D within the range of 1 mm≦D≦2 mm and combining it with the welding method of the present invention, it is possible to improve welding yield while maintaining a high energy density of the battery 100.

[0067] In some embodiments, the tab 114 is a copper tab 114, and the electrode adapter 2 is a copper sheet. Copper has excellent thermal conductivity and heat absorption properties, is highly sensitive to high temperatures, and is subject to significant thermal impact on the negative electrode. Furthermore, the copper negative electrode tab 114 is easily crushed during welding, so it is closer to the separator 113 with the same pressure. Therefore, by adopting the solution to the welding marks of this embodiment, it is possible to avoid the occurrence of welding explosion points, welding defects, and separator burnout when welding the copper tab 114 and the electrode adapter 2.

[0068] Below, the inventors of the present invention provide a table showing the shape of the weld marks and the results of measuring burn damage to bare cells when welding the tab 114 and the electrode adapter 2 to form weld marks of different sizes.

[0069] [Table 1] JPEG2026015223000003.jpg42160

[0070] According to the analysis of the above table, when embodiments 1 to 4 are combined, if the radius of curvature of the weld mark 3 is less than 0.5 mm, welding explosion points due to the concentration of welding heat are likely to occur in the peripheral area of ​​the weld mark 3, and burning of the separator 113 of the bare cell 1 is likely to occur. When embodiments 5 to 6, 8 to 9, and 11 to 16 are combined, if the radius of curvature of the weld mark 3 is 0.5 mm or more, it is possible to prevent welding explosion points due to the concentration of welding heat from occurring in the peripheral area of ​​the weld mark, and thereby prevent burning of the separator 113 of the bare cell 1.

[0071] When the fifth to sixteenth embodiments are combined, the radius of curvature R at the minimum point of the radius of curvature on the weld mark 3 min and the width of the weld mark w is 2R minIt can be seen that when -w≧0.5 mm is satisfied, the shape of the weld mark 3 is better and the phenomenon of burnout of the separator 113 does not occur. From analysis, it can be seen that when the above relationship is satisfied, the overlap of the heat-affected zones between the weld marks 3 on both sides of the point of the minimum radius of curvature can be reduced and the phenomenon of burnout of the separator 113 due to secondary welding does not occur.

[0072] In summary, the battery 100 of the present invention can prevent the concentration of welding heat and the associated problem of welding explosion points by adjusting the radius of curvature at any one point on the weld mark 3 between the bare cell 1 and the electrode adapter 2 to 0.5 mm or more, thereby ensuring welding quality and improving the product acceptance rate of the battery 100.

[0073] An electronic device according to a third embodiment of the present invention will now be described.

[0074] The electronic device of this embodiment includes the battery 100 of the above embodiment.

[0075] The electronic device according to the embodiment of the present invention includes the battery 100 according to the above embodiment, so that the battery 100 can supply power to the electronic device more reliably, thereby contributing to an improved user experience.

[0076] It should be noted that while the embodiments represented by terms such as "one embodiment," "embodiment," "exemplary embodiment," "some embodiments," etc., referred to herein, may include a particular feature, structure, or characteristic, not all embodiments necessarily include the particular feature, structure, or characteristic. Furthermore, such terms do not necessarily refer to the same embodiment. Furthermore, when a particular feature, structure, or characteristic is described in conjunction with an embodiment, it is within the knowledge of one skilled in the art to implement such feature, structure, or characteristic in conjunction with other embodiments, whether or not explicitly described.

[0077] In general, terms should be understood, at least in part, by their usage in the context in which they are used. For example, depending, at least in part, on the context, the term "one or more" as used herein may be used in the singular sense to describe any feature, structure, or characteristic, or may be used in the plural sense to describe a combination of features, structures, or characteristics. Similarly, terms such as "a," "the," and "said" may be interpreted as referring to the singular or the plural, depending on the context.

[0078] It should be readily understood that "on...", "above..." and "on..." in this disclosure should be interpreted in the broadest sense, and that "on..." not only means "directly on top of something" but also includes the meaning of "on top of something" with an intervening feature or layer, and that "above..." or "on..." not only means "above..." or "on top of..." but can also include the meaning of "above..." or "on..." without an intervening feature or layer (i.e., directly on top of something).

[0079] Also, for convenience of description, spatially relative terms, such as "below," "below," "directly below," "above," "up," etc., may be used to describe the relationship of one element or feature to another, such as the relationship shown in the drawings. The spatially relative terms are intended to encompass various orientations of the device in use or operation in addition to the orientation depicted in the drawings. The device may have other orientations (rotated 90 degrees or at other orientations) and the spatially relative terms used herein should be interpreted accordingly.

[0080] Finally, it should be noted that the above embodiments are used solely to describe the technical solutions of the present application, and are not intended to limit the same. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions described in the above embodiments can be modified, or some or all of the technical features therein can be equivalently replaced. 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. [Industrial Applicability]

[0081] The battery and electronic device of the present invention can be applied to the field of battery technology. [Explanation of symbols]

[0082] 1: Bare Cell 2: Electrode adapter 3: Weld marks 31: Welded segment 32: Arc segment 4: Welding group 5: Housing assembly 51: Shell 511: Upper wall 512: Side wall 52: cover plate; 6: Positive current collector plate 7: Terminal 100:Battery 111: Positive electrode sheet 1111: Positive electrode current collector 1112: Positive electrode active coating layer 1113: Positive electrode tab 112: Negative electrode sheet 1121: Negative electrode current collector 1122: Negative electrode active coating layer 113: Separator 114: Tab 1140: Connection sheet 1141: Tab end face 200: Welding equipment B: Welding focus N: Extend the baseline G: Migration Point L1: Distance L2, L3, L4: Spacing R: Radius of curvature R2: Diameter

Claims

1. a housing assembly; a bare cell provided within the housing assembly, the bare cell including a positive electrode sheet, a negative electrode sheet, and a separator, the positive electrode sheet, the separator, and the negative electrode sheet being stacked in order and wound around a winding axis, the bare cell having a tab at one end along the winding axis; an electrode adapter welded to the tab to form at least one continuous weld mark, at least a portion of the weld mark extending from an outer periphery to an inner periphery of the bare cell, the weld mark including a circular arc segment; Including, The radius of curvature R at any part of the weld mark is 0.5 mm or more. A battery characterized by:

2. The weld mark has an extension reference line, the extension reference line divides the weld mark into a plurality of weld segments arranged sequentially along an extension direction of the extension reference line, and any two adjacent weld segments are located on opposite sides of the extension reference line, respectively.

2. The battery of claim 1 .

3. The extended reference line is a straight line.

3. The battery according to claim 2 .

4. Among the plurality of welded segments, at least the remaining welded segments other than both ends of the weld mark all have a transition point, the distance between the transition point and the extended reference line is greater than the distance between any one point on either side of the transition point and the extended reference line; Furthermore, the transition point is located on the arc segment.

4. The battery according to claim 3 .

5. The distances from the transition points of any two of the weld segments to the extended reference line are equal.

5. The battery according to claim 4.

6. Any two adjacent welded segments are symmetrical with respect to a connection point of the two welded segments.

6. The battery according to claim 5 .

7. The welding segment is arc-shaped, or the welding segment includes the arc segment and non-arc segments located on both sides of the arc segment.

4. The battery according to claim 3 .

8. When the weld segment is arc-shaped, the weld segment is a portion of a circle.

8. The battery according to claim 7.

9. a span-depth ratio A of the weld segment satisfies 0<A<3, where A=H / L, H is the distance between the transition point of the weld segment and a line connecting both ends of the weld segment, and L is the length of the line connecting the ends of the weld segment; 6. The battery according to claim 5 .

10. a height-to-span ratio A of the welded segment satisfies 0.25≦A≦1; 10. The battery according to claim 9.

11. The width w of the weld mark ranges from 0.2 mm to 0.8 mm.

2. The battery of claim 1 .

12. The radius of curvature R at the minimum point of the radius of curvature on the weld mark ｍｉｎ is 2R ｍｉｎ -w≧0.5mm is satisfied, 12. The battery of claim 11 .

13. The welding mark has a first end close to the center of the bare cell along the extension reference line and a second end far from the center of the bare cell, and a distance L1 between the first end and the second end satisfies 6 mm≦L1≦15 mm; and / or A distance L2 between the first end and the center of the bare cell in the direction of the extension reference line satisfies 0 mm≦L2≦10 mm; and / or a maximum gap distance L3 between the second end and the edge of the bare cell in the direction of the extension reference line satisfies 0 mm≦L3≦10 mm; 4. The battery according to claim 3 .

14. a plurality of the welding marks are provided, an extension reference line of each of the welding marks extends along a radial direction of the bare cell, and the plurality of welding marks are provided at intervals along a circumferential direction of the bare cell; 4. The battery according to claim 3 .

15. the weld marks are plural, the plural weld marks are divided into several weld groups, and the several weld groups are provided at intervals along the circumferential direction of the bare cell; Each of the welding groups includes several welding marks that are parallel to each other and spaced apart, and further, an extension reference line of one of the welding marks in each of the welding groups extends along a radial direction of the bare cell; The interval distance L4 between two adjacent weld marks belonging to the same weld group satisfies 0.5 mm≦L4≦5 mm.

4. The battery according to claim 3 .

16. At one end of the bare cell along the winding axis, an end of the separator extends beyond the end of the positive electrode sheet, and an end of the negative electrode sheet extends beyond the end of the separator; further, the portion of the negative electrode sheet extending beyond the separator includes the tab, and the tab includes a plurality of connecting sheets that can be bent independently, and each of the plurality of connecting sheets is folded toward the center of the bare cell, and the folded plurality of connecting sheets form a tab end surface, and a value range of a gap D between the tab end surface and the separator in the axial direction of the bare cell is 1 mm≦D≦2 mm.

2. The battery of claim 1 .

17. The tab is a copper tab and the electrode adapter is a copper sheet.

2. The battery of claim 1 .

18. 18. An electronic device comprising the battery according to claim 1.

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