Ultrasonic welding head, wear detection method, single battery, battery device and power utilization device

Abstract

The invention discloses an ultrasonic welding head, a wear detection method, a single battery, a battery device and a power utilization device, and belongs to the technical field of batteries, and the ultrasonic welding head comprises a welding head main body, a first welding tooth structure and a second welding tooth structure. The welding head body is provided with a welding face, the first welding tooth structure is arranged on the welding face in a protruding mode, the second welding tooth structure is arranged on the side, away from the welding face, of the first welding tooth structure in a protruding mode, the second welding tooth structure comprises at least one second welding tooth, and the second welding tooth extends in a long-strip-shaped mode in the extending direction of the welding face. According to the ultrasonic welding head disclosed by the embodiment of the invention, the second welding tooth structure is additionally arranged on one side, far away from the welding surface, of the first welding tooth structure of the ultrasonic welding head, so that the multi-layer foil can be subjected to multi-stage upsetting and pressing, and the overall compaction effect of the first welding tooth structure and the second welding tooth structure on the welding of the multi-layer foil is enhanced; and gaps among the multiple layers of foils are reduced, so that the welding quality of a subsequent welding procedure is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and in particular to an ultrasonic welding head and a wear detection method, a battery cell, a battery device and an electrical device. Background Art

[0002] In the related art, in order to further improve the energy density of the battery cell, the adapter for connecting the tab and the electrode terminal is omitted, and the tab of the electrode assembly is directly connected to the electrode terminal on the shell of the battery cell without an adapter. The connection process of the tab of the electrode assembly and the electrode terminal is as follows: firstly, the multi-layer tab sheet is pre-welded by ultrasonic so that the multi-layer tab sheet is welded and connected to form an integral tab, and then the tab and the electrode terminal are connected by laser welding.

[0003] However, in the related art, the process of laser welding the tabs and electrode terminals is prone to welding defects such as explosion points and collapse, and it is easy to produce many welding defects such as cracks on the tabs. The welding quality of the laser welding process is poor, which affects the service stability of the battery. Therefore, how to improve the laser welding quality of the tabs and electrode terminals and improve the service stability of the battery is a technical problem that needs to be solved urgently. Summary of the invention

[0004] The present invention provides an ultrasonic welding head and a wear detection method, a battery cell, a battery device and an electrical device. When the ultrasonic welding head is used to weld a workpiece of multi-layer foil such as a tab, it can be compacted to reduce the gap between the multi-layer foils, thereby helping to improve the welding quality of subsequent welding processes.

[0005] In a first aspect, the present invention provides an ultrasonic welding head, comprising: a welding head body, the welding head body having a welding surface; a first welding tooth structure, the first welding tooth structure being protruded from the welding surface; a second welding tooth structure, the second welding tooth structure being protruded from a side of the first welding tooth structure away from the welding surface, the second welding tooth structure comprising at least one second welding tooth, and the second welding tooth extending in a long strip shape in the extension direction of the welding surface.

[0006] In the above technical solution, by adding a second tooth structure on the side of the first tooth structure of the ultrasonic welding head away from the welding surface, multi-stage upsetting can be performed on multi-layer foils, the compaction effect of the overall welding of the multi-layer foils by the first tooth structure and the second tooth structure can be enhanced, the gap between the multi-layer foils can be reduced, which helps to improve the welding quality of subsequent welding processes. For example, when the subsequent welding process is a laser welding process, welding defects such as blowholes and collapses generated during laser welding can be reduced, and welding cracks can also be reduced. Moreover, due to the reduction of the gap between the multi-layer foils, it is beneficial to improve the heat dissipation uniformity of the laser welding joint, thereby facilitating the improvement of the foil cracking problem caused by excessive local stress of the foil; and, by setting the second tooth to extend in a long strip shape in the extending direction of the welding surface, the contact length between the second tooth structure and the surface of the multi-layer foils can be increased, further enhancing the compaction effect between the multi-layer foils, so that the gap between the multi-layer foils can be further reduced, which is more conducive to improving the welding quality of subsequent welding processes. For example, when the subsequent welding process is a laser welding process, since the compaction between the multi-layer foils at the weld mark position corresponding to the second tooth is tighter and the gap is smaller, laser welding can be performed at the weld mark position corresponding to the second tooth, which can better reduce laser welding defects and better improve the laser welding quality. When the ultrasonic welding head is used to weld multi-layer foils of the tab, it helps to improve the subsequent laser welding quality between the tab and the electrode terminal, which is beneficial to improving the service stability of the battery.

[0007] In some embodiments, both ends of the second tooth in the length direction extend to opposite ends of the welding surface.

[0008] In the above technical solution, by extending both ends of the second tooth in the length direction to opposite ends of the welding surface, the length of the second tooth can be increased. During ultrasonic welding, the contact length between the second tooth structure and the surface of the multi-layer foils is relatively long, further enhancing the compaction effect of the second tooth structure on the multi-layer foils; and, due to the relatively long length of the second tooth, the weld mark corresponding to the second tooth is relatively long. In this way, when laser welding is performed on the weld mark position corresponding to the second tooth in the subsequent welding process, the length of the laser welding can be relatively long, which is beneficial to improving the reliability and stability of subsequent welding connections; for example, after the ultrasonic welding head is used to weld multi-layer foils of the tab, when the subsequent welding process is a laser welding process, the laser weld between the tab and the electrode terminal can be relatively long, which helps to improve the stability and reliability of the welding connection between the tab and the electrode terminal.

[0009] In some embodiments, the second tooth extends along the length direction of the welding surface.

[0010] In the above technical solution, by extending the second welding tooth along the length direction of the welding surface, the space in the length direction of the welding surface can be utilized, the length of the second welding tooth can be increased, and when ultrasonic welding is performed, the contact length between the second welding tooth structure and the surface of the multi-layer foil is longer, enhancing the compaction effect of the second welding tooth structure on the multi-layer foil.

[0011] In some embodiments, the second welding tooth extends along the width direction of the welding surface.

[0012] In the above technical solution, by extending the second welding tooth along the width direction of the welding surface, the space in the width direction of the welding surface can be utilized, and it is also beneficial to increase the arrangement number of the second welding teeth. When ultrasonic welding is performed, the contact area between the second welding tooth structure and the surface of the multi-layer foil is larger, enhancing the compaction effect of the second welding tooth structure on the multi-layer foil.

[0013] In some embodiments, the second welding tooth extends along a straight line.

[0014] In the above technical solution, by providing the second welding tooth extending along a straight line, the structure of the second welding tooth can be made simple and convenient for processing and forming; moreover, the welding marks corresponding to the second welding tooth extending along a straight line also basically extend along a straight line. In this way, in the subsequent welding process, welding connection can be carried out along a straight line, making the design of the subsequent welding process relatively simple.

[0015] In some embodiments, the second welding teeth are multiple and arranged at intervals.

[0016] In the above technical solution, by providing multiple second welding teeth arranged at intervals, the multiple second welding teeth can compact multiple different positions of multiple multi-layer foils, so that the gaps at multiple different positions of the multi-layer foils can be reduced, which helps to improve the quality of the subsequent welding process.

[0017] In some embodiments, the multiple second welding teeth are arranged side by side along the width direction of the second welding tooth.

[0018] In the above technical solution, by arranging the multiple second welding teeth side by side along the width direction of the second welding tooth, the contact area between the second welding tooth structure and the surface of the multi-layer foil can be increased, enhancing the compaction effect on the multi-layer foil, so that the gaps at different positions in the width direction of the second welding tooth of the multi-layer foil can be reduced, which helps to improve the quality of the subsequent welding process.

[0019] In some embodiments, the second welding tooth extends along the length direction of the welding surface, and the multiple second welding teeth are arranged along the width direction of the welding surface.

[0020] In the above technical solution, by extending the second welding teeth along the length direction of the welding surface, the space in the length direction of the welding surface can be fully utilized, so that the extension length of the second welding teeth is longer, and a plurality of second welding teeth are arranged along the width direction of the welding surface, and the distribution of the plurality of second welding teeth is relatively uniform, which can increase the contact length and contact area between the second welding teeth structure and the workpiece surface, make the contact between the second welding teeth structure and the workpiece surface more uniform, and make the heat inside the workpiece more evenly distributed, and can enhance the compaction effect on the workpiece surface.

[0021] In some embodiments, in the arrangement direction of the plurality of second welding teeth, the distance between two adjacent second welding teeth is d1, and the maximum width of the second welding teeth is W2, and W2 < d1.

[0022] In the above technical solution, by making the maximum width W2 of the second welding teeth less than the distance d1 between two adjacent second welding teeth, the width of the second welding teeth can be made smaller. Under a certain welding pressure, the second welding teeth can generate a larger pressure on the multi-layer foils, and further enhance the compaction effect between the multi-layer foils.

[0023] In some embodiments, the ratio range of W2 to d1 is 0.2 to 0.8.

[0024] In the above technical solution, by setting the ratio of the maximum width W2 of the second welding teeth to the distance d1 between two adjacent second welding teeth within the range of 0.2 to 0.8, while being able to generate a larger pressure on the multi-layer foils under a certain welding pressure, the contact area between the second welding teeth structure and the surface of the multi-layer foils is larger, and the compaction effect between the multi-layer foils is enhanced.

[0025] In some embodiments, in the arrangement direction of the plurality of second welding teeth, the minimum distance between the second welding teeth and the edge of the welding surface is d2, and the maximum width of the second welding teeth is W2, and d2 > W2.

[0026] In the above technical solution, by making the minimum distance d2 between the second welding teeth and the edge of the welding surface greater than the maximum width W2 of the second welding teeth, a certain distance can be provided between the second welding teeth and the edge of the welding surface, which can enable the second welding teeth to better compact the multi-layer foils, thereby enhancing the compaction effect between the multi-layer foils.

[0027] In some embodiments, the cross-section of the second welding teeth is a second cross-section, and the second cross-section has a tapered portion, and the tapered portion extends to the side of the second welding teeth away from the welding surface, and in the direction from the welding surface to the second welding teeth, the width of the tapered portion gradually decreases.

[0028] In the above technical solution, by making the width of the tapered portion of the second welding tooth gradually decrease in the direction from the welding surface to the second welding tooth, under a certain welding pressure, the second welding tooth can have a relatively large pressure on the multi-layer foil, thereby enhancing the compaction effect between the second welding tooth and the multi-layer foil.

[0029] In some embodiments, in the extending direction of the second welding tooth, the cross-sectional areas of at least some portions of the second welding tooth are the same.

[0030] In the above technical solution, by making the cross-sectional areas of at least some portions of the second welding tooth in the extending direction the same, it is possible to keep the compaction of the second welding tooth on the multi-layer foil relatively uniform in the extending direction, thereby enhancing the compaction effect between the second welding tooth and the multi-layer foil, and the width dimension of the weld mark corresponding to the second welding tooth in its extending direction is relatively uniform, facilitating the subsequent welding connection operation at the weld mark corresponding to the second welding tooth.

[0031] In some embodiments, the cross-section of the second welding tooth is bow-shaped, circular or elliptical.

[0032] In the above technical solution, by setting the cross-section of the second welding tooth to a shape such as bow-shaped, circular or elliptical, the surface of the second welding tooth is not likely to scratch the foil when it contacts the multi-layer foil.

[0033] In some embodiments, the second welding tooth includes one tooth portion.

[0034] In the above technical solution, by making the second welding tooth include one tooth portion, the structure of the second welding tooth can be simple and convenient for processing and forming.

[0035] In some embodiments, the second welding tooth includes a plurality of tooth portions. The surface of the tooth portion on the side away from the welding surface constitutes the tooth portion end face. The plurality of tooth portions are respectively the first tooth portion to the mth tooth portion arranged in sequence along the protruding direction of the second welding tooth. The nth tooth portion is provided on the tooth portion end face of the (n - 1)th tooth portion. The projection of the nth tooth portion on the tooth portion end face of the (n - 1)th tooth portion is located within the tooth portion end face of the (n - 1)th tooth portion, where 2 ≤ n ≤ m.

[0036] In the above technical solution, by setting the second welding tooth to include a plurality of tooth parts, and the plurality of tooth parts are respectively the first tooth part to the m-th tooth part arranged in sequence along the protruding direction of the second welding tooth, the n-th tooth part is arranged on the tooth end face of the (n - 1)-th tooth part, and the projection of the n-th tooth part on the tooth end face of the (n - 1)-th tooth part is located within the tooth end face of the (n - 1)-th tooth part, so that the part of the tooth end face of the (n - 1)-th tooth part on the side away from the welding surface exceeding the n-th tooth part can form a welding pier pressing surface. Thus, when the ultrasonic welding head welds the multi-layer foils, each tooth part can tamp and press the multi-layer foils, so as to realize multi-layer pressing and tamping of the welding material, further enhance the compaction effect between the multi-layer foils, better reduce the gap between the multi-layer foils, and further reduce the welding energy loss and the influence on the subsequent welding process easily caused by the too large interlayer gap of the multi-layer foils, which helps to better improve the welding quality of the subsequent welding process.

[0037] In some embodiments, the first welding tooth structure includes a first welding tooth, the surface of the first welding tooth on the side away from the welding surface constitutes a tooth end face, the second welding tooth is arranged on the tooth end face, and the projection of the second welding tooth on the tooth end face is located within the tooth end face.

[0038] In the above technical solution, by arranging the second welding tooth within the tooth end face of the first welding tooth, this can make the boundary between the second welding tooth and the first welding tooth obvious, which is more conducive to forming a multi-stage welding tooth structure between the first welding tooth and the second welding tooth, and is more conducive to realizing multi-stage pressing of the multi-layer foils, and the compaction effect is better.

[0039] In some embodiments, in the protruding direction of the first welding tooth relative to the welding surface, the tooth height of the first welding tooth is h1, the tooth height of the second welding tooth is h2, and the ratio range of h2 to h1 is 0.3 - 0.8.

[0040] In the above technical solution, by making the ratio of the tooth height h2 of the second welding tooth to the tooth height h1 of the first welding tooth not less than 0.3, the second welding tooth can have a relatively high tooth height, so that the second welding tooth has a good compaction effect on the multi-layer foils; and by making the ratio of the tooth height h2 of the second welding tooth to the tooth height h1 of the first welding tooth not greater than 0.8, it can be ensured that the second welding tooth will not affect the welding effect of the first welding tooth due to too high a tooth height. In this way, it can better avoid the influence on the contact between the first welding tooth and the multi-layer foils due to too high a tooth height of the second welding tooth. Thus, when the ultrasonic welding head welds the multi-layer foils, both the first welding tooth and the second welding tooth can fully contact the multi-layer foils, and the contact area between the first welding tooth and the second welding tooth and the multi-layer foils is relatively large, which can improve the compaction effect on the multi-layer foils.

[0041] In some embodiments, in the protruding direction of the first welding tooth relative to the welding surface, the tooth height of the first welding tooth is h1, and the value range of h1 is 0.2 mm to 0.6 mm.

[0042] In the above technical solution, by making the tooth height h2 of the second welding tooth not less than 0.2 mm, the second welding tooth can have a relatively high tooth height, so that the second welding tooth has a better compaction effect on the multi-layer foil; and, by making the tooth height h2 of the second welding tooth not greater than 0.6 mm, it can be ensured that the second welding tooth will not affect the welding effect of the first welding tooth due to excessive tooth height. In this way, it can better avoid the influence of the excessive tooth height of the second welding tooth on the contact between the first welding tooth and the multi-layer foil. Therefore, when the ultrasonic welding head welds the multi-layer foil, the first welding tooth and the second welding tooth can both fully contact the multi-layer foil, resulting in a relatively large contact area between the first welding tooth and the second welding tooth and the multi-layer foil, which can improve the compaction effect on the multi-layer foil.

[0043] In some embodiments, the end face of the welding tooth is a plane.

[0044] In the above technical solution, by setting the end face of the first welding tooth as a plane, the contact area between the first welding tooth and the multi-layer foil can be increased, and the compaction area for the multi-layer foil can be enlarged, which is beneficial to improving the compaction effect on the multi-layer foil.

[0045] In some embodiments, the structure of the first welding tooth includes a third welding tooth, and the third welding tooth is arranged between adjacent first welding teeth.

[0046] In the above technical solution, by arranging the third welding tooth between adjacent first welding teeth, the part of the multi-layer foil located between adjacent first welding teeth can be compacted by the third welding tooth, so that the multi-layer foil is compacted more evenly, which is beneficial to improving the welding quality of subsequent welding processes.

[0047] In some embodiments, the structure of the first welding tooth includes a fourth welding tooth, and the fourth welding tooth is arranged between the first welding tooth and the edge of the welding surface.

[0048] In the above technical solution, by arranging the fourth welding tooth between the first welding tooth and the edge of the welding surface, the part of the multi-layer foil located between the first welding tooth and the edge of the welding surface can be compacted by the fourth welding tooth, so that the multi-layer foil is compacted more evenly, which is beneficial to improving the welding quality of subsequent welding processes; and, the fourth welding tooth can also reduce the situation of the edge of the first welding tooth scratching the multi-layer foil.

[0049] In some embodiments, the first welding tooth includes a welding tooth body and a plurality of welding tooth branches. The welding tooth body extends in a strip shape in the extending direction of the welding surface. The plurality of welding tooth branches are connected to at least one side in the width direction of the welding tooth body. The second welding tooth is arranged on the welding tooth body and is consistent with the extending direction of the welding tooth body.

[0050] In the above technical solution, by setting the first welding tooth to include a welding tooth body and a plurality of welding tooth branches, and connecting the plurality of welding tooth branches to at least one side in the width direction of the welding tooth body, the contact area between the first welding tooth and the multi-layer foil can be increased, which is beneficial to enhancing the compaction uniformity and compaction effect on the multi-layer foil. By arranging the second welding tooth on the welding tooth body and being consistent with the extending direction of the welding tooth body, the contact length between the second welding tooth structure and the surface of the multi-layer foil is increased, and the compaction effect between the multi-layer foils by the second welding tooth is enhanced.

[0051] In some embodiments, the width of the second welding tooth is W2, and the width of the welding tooth body is W1, and W2 ≤ W1.

[0052] In the above technical solution, by making the width W2 of the second welding tooth less than or equal to the width W1 of the welding tooth body, the width of the welding tooth body of the first welding tooth can be made larger, which can provide a sufficient support area for the second welding tooth, and make the contact area between the first welding tooth and the multi-layer foil larger, and can further enhance the compaction effect of the second welding tooth on the multi-layer foil.

[0053] In some embodiments, the ratio range of W2 to W1 is 0.5 to 0.9.

[0054] In the above technical solution, by making the ratio of the width W2 of the second welding tooth to the width W1 of the welding tooth body not less than 0.5, the contact area between the second welding tooth and the multi-layer foil can be made larger, the compaction range can be larger, and the compaction effect can be better. And by making the ratio of the width W2 of the second welding tooth to the width W1 of the welding tooth body not greater than 0.9, a multi-stage welding tooth structure can be better formed between the second welding tooth and the first welding tooth, which is more beneficial to realizing multi-stage upset pressing on the multi-layer foil and has a better compaction effect.

[0055] In some embodiments, the first welding tooth structure includes a third welding tooth. A plurality of receiving grooves are defined between adjacent two of the first welding teeth. The plurality of receiving grooves are arranged at intervals along the extending direction of the welding tooth body. The welding tooth branches are located between adjacent two of the receiving grooves. The third welding tooth is located in the receiving groove.

[0056] In the above technical solution, by defining a plurality of receiving grooves between two adjacent first welding teeth, the plurality of receiving grooves are arranged at intervals along the extending direction of the welding tooth body, and third welding teeth are arranged in the receiving grooves, the contact area between the first welding tooth structure and the multi-layer foil can be further increased, so that the portion of the multi-layer foil located between adjacent first welding teeth can be compacted by the third welding teeth, thereby making the multi-layer foil compacted more evenly, which is beneficial to improving the welding quality of subsequent welding processes.

[0057] In some embodiments, the third welding teeth are in the shape of a frustum of a pyramid.

[0058] In the above technical solution, by making the third welding teeth in the shape of a frustum of a pyramid, a larger contact area and better compaction effect can be achieved between the third welding teeth and the multi-layer foil, and a welding pier pressing surface can be formed on the contact surface between the third welding teeth and the multi-layer foil, providing a larger heat transfer area, which is beneficial to reducing welding cracks caused by local stress concentration in the multi-layer foil.

[0059] In some embodiments, the first welding tooth structure includes fourth welding teeth, the fourth welding teeth are arranged between the first welding teeth and the edge of the welding surface, and there are a plurality of the fourth welding teeth, and the plurality of the fourth welding teeth located on the same side of the first welding teeth are arranged at intervals along the extending direction of the welding tooth body.

[0060] In the above technical solution, by arranging the fourth welding teeth between the first welding teeth and the edge of the welding surface, the portion of the multi-layer foil located between the first welding teeth and the edge of the welding surface can be compacted by the fourth welding teeth, thereby making the multi-layer foil compacted more evenly, which is beneficial to improving the welding quality of subsequent welding processes; moreover, the fourth welding teeth can also reduce the situation that the edges of the first welding teeth scratch the multi-layer foil; and by arranging the fourth welding teeth at intervals along the extending direction of the welding tooth body, the compaction of the fourth welding teeth on the multi-layer foil is more uniform and the compaction effect is better.

[0061] In a second aspect, the present invention provides an ultrasonic welding device, including: an ultrasonic welding head according to the embodiment of the first aspect.

[0062] In the above technical solution, by providing the above ultrasonic welding head, and by adding a second tooth structure on the side of the first tooth structure of the ultrasonic welding head away from the welding surface, multi-stage upsetting can be performed on multi-layer foils, the compaction effect of the overall welding of the multi-layer foils by the first tooth structure and the second tooth structure can be enhanced, the gap between the multi-layer foils can be reduced, which helps to improve the welding quality of subsequent welding processes. For example, when the subsequent welding process is a laser welding process, welding defects such as blowholes and collapses generated during the laser welding process can be reduced, and welding cracks can also be reduced. Moreover, since the gap between the multi-layer foils is reduced, it is beneficial to improve the heat dissipation uniformity of the laser welding joint, thereby helping to improve the problem of foil cracking caused by excessive local stress of the foil. Additionally, by setting the second teeth to extend in a strip shape in the extending direction of the welding surface, the contact length between the second tooth structure and the surface of the multi-layer foils can be increased, further enhancing the compaction effect between the multi-layer foils, so that the gap between the multi-layer foils can be further reduced, which is more conducive to improving the welding quality of subsequent welding processes. For example, when the subsequent welding process is a laser welding process, since the compaction between the multi-layer foils at the weld mark position corresponding to the second teeth is tighter and the gap is smaller, laser welding can be performed at the weld mark position corresponding to the second teeth, which can better reduce laser welding defects and better improve the laser welding quality. When the ultrasonic welding head is used to weld multi-layer foils of the tab, it helps to improve the subsequent laser welding quality between the tab and the electrode terminal, which is beneficial to improving the service stability of the battery.

[0063] In a third aspect, the present invention provides a method for detecting wear of an ultrasonic welding head. The ultrasonic welding head is the ultrasonic welding head according to the embodiments of the first aspect. The method for detecting wear of the ultrasonic welding head includes: Performing ultrasonic pre-welding on a workpiece sample by using the ultrasonic welding head, and the weld mark on the workpiece sample corresponding to the second teeth is the second weld mark; Identifying the second weld mark formed on the workpiece sample; Calculating the weld mark area of a single second weld mark; Judging the wear condition of the ultrasonic welding head according to the weld mark area of a single second weld mark.

[0064] In the above technical solution, by calculating the weld mark area of a single second weld mark on the workpiece sample corresponding to the second teeth, the wear condition of the second teeth in the ultrasonic welding head can be judged more intuitively and accurately, so that the ultrasonic welding head can be replaced in time or repaired, reducing the situation of poor welding of multi-layer foils and poor compaction effect caused by wear of the ultrasonic welding head, which affects subsequent welding processes, and helping to improve the compaction effect of the ultrasonic welding head on multi-layer foils.

[0065] In some embodiments, identifying the second welding mark formed on the workpiece sample includes: Collecting a welding mark image of the side of the workpiece sample where the welding mark is formed; Identifying the second welding mark in the welding mark image.

[0066] In the above technical solution, by collecting the welding mark image of the side of the workpiece sample where the welding mark is formed and identifying the second welding mark in the welding mark image, the second welding mark can be conveniently identified and found.

[0067] In some embodiments, calculating the welding mark area of a single second welding mark includes: Identifying the outer contour of a single second welding mark; Calculating the area of the figure enclosed by the outer contour of the second welding mark.

[0068] In the above technical solution, by first identifying the outer contour of a single second welding mark and then calculating the area of the figure enclosed by the outer contour of the second welding mark, the welding mark area of the second welding mark can be conveniently calculated. The calculation method of the welding mark area is simple and the calculation result is relatively accurate.

[0069] In some embodiments, judging the wear condition of the ultrasonic welding head according to the welding mark area of a single second welding mark includes: Judging the wear condition of the ultrasonic welding head according to the ratio of the welding mark area of a single second welding mark to the designed area of a single second welding mark.

[0070] In the above technical solution, by the magnitude relationship of the ratio of the welding mark area of a single second welding mark to the designed area of a single second welding mark, the amount by which the current welding mark area of the second welding mark is reduced relative to the designed area of the second welding mark can be obtained. The amount by which the welding mark area of the second welding mark is reduced relative to the designed area of the second welding mark can more intuitively reflect the wear condition of the second welding tooth, and thus can reflect the wear condition of the ultrasonic welding head, which helps to improve the accuracy of judging the wear condition of the ultrasonic welding head.

[0071] In some embodiments, judging the wear condition of the ultrasonic welding head according to the ratio of the welding mark area of a single second welding mark to the designed area of a single second welding mark includes: The welding mark area of a single second welding mark is Sx, and the designed area of a single second welding mark is S0. When the ratio of Sx to S0 is less than 0.2, it is judged that the life of the ultrasonic welding head has reached.

[0072] In the above technical solution, by determining whether the ratio of the welding area Sx of a single second weld mark to the designed area S0 of the single second weld mark is less than 0.2, it is possible to determine whether the life of the ultrasonic welding head has reached, and it is possible to simply and accurately determine whether the ultrasonic welding head should be replaced or repaired.

[0073] Fourthly, the present invention provides a battery cell, including: a housing provided with electrode terminals; an electrode assembly disposed in the housing and including tab ears, the tab ears being connected to the electrode terminals, the tab ears including a plurality of tab ear pieces stacked and welded together, a weld mark area being formed on the tab ears, the weld mark area being formed by welding with the ultrasonic welding head according to the embodiments of the first aspect, the weld mark area including a first weld mark and a second weld mark, both the first weld mark and the second weld mark being formed in a groove structure, and the second weld mark being formed on the bottom wall of the first weld mark and extending in a long strip shape.

[0074] In the above technical solution, by welding on the multi-layer tab ear pieces of the tab ear to form the first weld mark and the second weld mark both in groove structures, during the welding process of the multi-layer tab ear pieces, the multi-layer tab ear pieces can be compacted, the air between the multi-layer tab ear pieces can be discharged, the gap between the multi-layer tab ear pieces is reduced, and problems such as explosion points, collapse, welding cracks, and tab ear piece cracking caused by the existence of air between the multi-layer tab ear pieces in the subsequent welding process are reduced; by the second weld mark being formed on the bottom wall of the first weld mark and extending in a long strip shape, the second weld mark and the first weld mark can form a multi-stage weld mark structure and the length of the second weld mark is relatively large. During the welding process of the multi-layer tab ear pieces, the compaction effect on the multi-layer tab ear pieces can be further enhanced, thereby further reducing the gap between the multi-layer tab ear pieces, which is more conducive to improving the welding quality of the subsequent welding process. For example, when the subsequent welding process is a laser welding process, the compaction between the multi-layer tab ear pieces at the position of the second weld mark is tighter and the gap is smaller. In this way, laser welding can be performed at the position of the second weld mark, which can better reduce laser welding defects, better improve the laser welding quality, contribute to improving the laser welding quality of the subsequent tab ear and the electrode terminal, and is beneficial to improving the service stability of the battery.

[0075] In some embodiments, the first weld mark includes a weld mark main body and a plurality of weld mark branches, the weld mark main body is in a long strip shape, and the plurality of weld mark branches are connected to at least one side in the width direction of the weld mark main body, and the second weld mark is formed on the bottom wall of the weld mark main body and is consistent with the extending direction of the weld mark main body.

[0076] In the above technical solution, by making the first weld mark on the tab include a weld mark body and a plurality of weld mark branches, and making the weld mark body strip-shaped, the weld mark area and weld mark length of the first weld mark can be increased, which is beneficial to enhancing the compaction uniformity and compaction effect on the multi-layer tab pieces. By forming the second weld mark on the bottom wall of the weld mark body and in the same extension direction as the weld mark body, the weld mark length and weld mark area of the second weld mark can be increased, which is beneficial to enhancing the compaction effect between the multi-layer tab pieces.

[0077] In some embodiments, the weld mark area includes a third weld mark, and the third weld mark is located between adjacent first weld marks.

[0078] In the above technical solution, by arranging a third weld mark between adjacent first weld marks, the weld mark area can be further increased, so that the part of the multi-layer tab pieces located between adjacent first weld marks can be compacted by the third weld mark, thereby making the multi-layer tab pieces compacted more uniformly, which is beneficial to improving the welding quality of subsequent welding processes.

[0079] In some embodiments, the weld mark area includes a fourth weld mark, and the fourth weld mark is located between the first weld mark and the edge of the tab.

[0080] In the above technical solution, by printing a fourth weld mark in the weld mark area between the first weld mark of the tab and the edge of the tab, the part of the multi-layer tab pieces located between the first weld mark and the edge of the tab can be compacted by the fourth weld mark, thereby making the multi-layer tab pieces compacted more uniformly, which is beneficial to improving the welding quality of subsequent welding processes.

[0081] In some embodiments, the multi-layer tab pieces of the tab are connected by ultrasonic welding, and the tab is connected to the electrode terminal by laser welding to form a laser weld seam, and the laser weld seam and the second weld mark are oppositely arranged in the stacking direction of the multi-layer tab pieces.

[0082] In the above technical solution, by connecting the multi-layer tab pieces of the tab by ultrasonic welding, the above-mentioned weld mark area is formed on the tab during ultrasonic welding, and the weld mark area includes the above-mentioned first weld mark and second weld mark. During ultrasonic welding, the multi-layer tab pieces can be compacted, the gap between the multi-layer tab pieces can be reduced, which is convenient for laser welding connection between the tab and the electrode terminal, and the generation of situations such as tab piece explosion points and collapse during laser welding can be reduced, the laser welding quality between the tab and the electrode terminal can be improved, and it is beneficial to improve the service stability of the battery.

[0083] In a fifth aspect, the present invention provides a battery device, including: a box body; a battery cell according to the embodiments of the fourth aspect, disposed in the box body.

[0084] In the above technical solution, by providing the above battery cell, first weld marks and second weld marks both having a groove structure are formed by welding on the multi-layer tab pieces of the tab. During the welding process of the multi-layer tab pieces, the multi-layer tab pieces can be compacted, the air between the multi-layer tab pieces can be discharged, the gap between the multi-layer tab pieces is reduced, and problems such as explosion points, collapse, welding cracks, and tab piece cracking caused by the existence of air between the multi-layer tab pieces in the subsequent welding process are reduced. Since the second weld mark is formed on the bottom wall of the first weld mark and extends in a long strip shape, the second weld mark and the first weld mark can form a multi-stage weld mark structure and the length of the second weld mark is relatively large. During the welding process of the multi-layer tab pieces, the compaction effect on the multi-layer tab pieces can be further enhanced, so that the gap between the multi-layer tab pieces can be further reduced, which is more helpful for improving the welding quality of the subsequent welding process. For example, when the subsequent welding process is a laser welding process, the compaction between the multi-layer tab pieces at the position of the second weld mark is tighter and the gap is smaller. In this way, laser welding can be performed at the position of the second weld mark, which can better reduce laser welding defects, better improve the laser welding quality, help improve the laser welding quality between the subsequent tab and the electrode terminal, and is beneficial to improving the service stability of the battery.

[0085] In a sixth aspect, the present invention provides an electrical device including the battery device of the embodiment of the fifth aspect.

[0086] In the above technical solution, by providing the above battery device, the battery cell provided in the battery device, first weld marks and second weld marks both having a groove structure are formed by welding on the multi-layer tab pieces of the tab. During the welding process of the multi-layer tab pieces, the multi-layer tab pieces can be compacted, the air between the multi-layer tab pieces can be discharged, the gap between the multi-layer tab pieces is reduced, and problems such as explosion points, collapse, welding cracks, and tab piece cracking caused by the existence of air between the multi-layer tab pieces in the subsequent welding process are reduced. Since the second weld mark is formed on the bottom wall of the first weld mark and extends in a long strip shape, the second weld mark and the first weld mark can form a multi-stage weld mark structure and the length of the second weld mark is relatively large. During the welding process of the multi-layer tab pieces, the compaction effect on the multi-layer tab pieces can be further enhanced, so that the gap between the multi-layer tab pieces can be further reduced, which is more helpful for improving the welding quality of the subsequent welding process. For example, when the subsequent welding process is a laser welding process, the compaction between the multi-layer tab pieces at the position of the second weld mark is tighter and the gap is smaller. In this way, laser welding can be performed at the position of the second weld mark, which can better reduce laser welding defects, better improve the laser welding quality, help improve the laser welding quality between the subsequent tab and the electrode terminal, and is beneficial to improving the service stability of the battery.

[0087] The additional aspects and advantages of the present invention will be partly given in the following description, partly will become obvious from the following description, or will be understood through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0088] The above and / or additional aspects and advantages of the present invention will become apparent and be readily understood from the following description of embodiments in conjunction with the accompanying drawings, where: Figure 1 is a schematic diagram of an ultrasonic welding head according to some embodiments of the present invention; Figure 2 is Figure 1 a partial schematic diagram of the ultrasonic welding head in Figure 3 is Figure 1 a schematic diagram of another angle of the ultrasonic welding head in Figure 4 is Figure 1 a side view of Figure 5 is Figure 4 an enlarged view of part A in Figure 6 is a schematic diagram of the ultrasonic welding head welding the tab of a battery cell according to some embodiments of the present invention; Figure 7 is Figure 6 an enlarged view of part B in Figure 8 is a schematic diagram of the first weld mark and the second weld mark on a workpiece sample according to some embodiments of the present invention; Figure 9 is a schematic diagram of a battery cell according to some embodiments of the present invention; Figure 10 is a schematic diagram of a battery device according to some embodiments of the present invention; Figure 11 is a schematic diagram of an electrical device according to some embodiments of the present invention.

[0089] Reference numerals: 100, ultrasonic welding head; 10, head body; 11, welding surface; 12, tooth end surface; 13, receiving groove; 20, first weld tooth structure; 21, first weld tooth; 211, weld tooth body; 212, weld tooth branch; 22, weld tooth end surface; 23, third weld tooth; 24, fourth weld tooth; 30, second weld tooth structure; 31, second weld tooth; 200, battery device; 201, box body; 40, battery cell; 41, housing; 401, electrode terminal; 42, tab; 43, weld mark area; 44, first weld mark; 45, second weld mark; 46, electrode assembly; 50, sample workpiece; 300, Electrical device; 60, Vehicle body. Detailed implementation manners

[0090] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0091] Unless otherwise defined, all technical and scientific terms used in the present invention have the same meanings as commonly understood by those skilled in the technical field to which the present invention belongs; the terms used in the description of the present invention in the specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention; the terms "comprising" and "having" and any variations thereof in the description and claims of the present invention and the above drawings are intended to cover non-exclusive inclusion. The terms "first", "second", etc. in the description and claims of the present invention or the above drawings are used to distinguish different objects and are not used to describe a specific order or primary-secondary relationship.

[0092] Referring to "embodiments" in the present invention means that specific features, structures or characteristics described in connection with the embodiments can be included in at least one embodiment of the present invention. The phrase appears in various positions in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments.

[0093] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected to", and "attached to" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0094] The term "and / or" in the present invention is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in the present invention generally represents an "or" relationship between the front and rear associated objects.

[0095] In the embodiments of the present invention, the same reference numerals denote the same components, and for the sake of brevity, in different embodiments, the detailed description of the same components is omitted. It should be understood that the thickness, length, width and other dimensions of various components in the embodiments of the present invention shown in the drawings, as well as the overall thickness, length, width and other dimensions of the integrated device are only for illustrative purposes and should not constitute any limitation to the present invention.

[0096] The "plurality" mentioned in the present invention refers to two or more (including two).

[0097] In the embodiments of the present invention, if there is no special instruction, all embodiments and optional embodiments of the present invention can be combined with each other to form a new technical solution.

[0098] In the embodiments of the present invention, if there is no special instruction, all technical features and optional technical features of the present invention can be combined with each other to form a new technical solution.

[0099] In the embodiments of the present invention, the battery apparatus may include one or more battery cell assemblies for providing voltage and capacity. The battery cell assembly may include a plurality of battery cells, and the plurality of battery cells are connected in series, parallel or in a hybrid connection through a bus bar component. For example, the battery cell assembly is usually formed by arranging a plurality of battery cells; the battery cell assembly may be a battery module, and the battery module is formed by arranging and fixing a plurality of battery cells to form an independent module. As an example, the battery module may be formed by bundling a plurality of battery cells with cable ties.

[0100] The battery apparatus may be a battery pack, and the battery pack includes a box body and one or more battery cell assemblies, and the battery cell assemblies are accommodated in the box body. The battery cell assembly may be a battery module, and the battery cell assembly may be accommodated in the box body by fixing the battery module in the box body; the battery cell assembly may also be accommodated in the box body by directly fixing a plurality of battery cells to the box body.

[0101] In the embodiments of the present invention, the box body may include a first box body and a second box body. The first box body and the second box body are snapped together so that a closed space is formed inside the box body to accommodate the battery cell assembly. The "closed" here means covering or closing, which may be sealed or non-sealed. The first box body may be a top cover or a bottom plate. For example, the box body may include a top cover, a frame and a bottom plate. The top cover and the bottom plate are respectively connected to the frame so that a closed space is formed inside the box body to accommodate the battery cell assembly.

[0102] In an embodiment of the present invention, the box body can be part of the chassis structure of a vehicle. For example, part of the box body can form at least part of the floor of the vehicle, or part of the box body can form at least part of the cross beams and longitudinal beams of the vehicle.

[0103] In an embodiment of the present invention, the battery cell can be a secondary battery, which refers to a battery cell that can be activated by charging after discharging so that the active material can be reused; the battery cell 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-metal hydride battery, a nickel-cadmium battery, a lead-acid battery, etc., and the embodiments of the present invention are not limited thereto. The battery cell can be in the shape of a cylinder, a flat body, a cuboid or other shapes, etc., and the embodiments of the present invention are not limited thereto either. Generally, the battery cells are divided into three types according to the encapsulation method: cylindrical battery cells, square battery cells and soft-pack battery cells, and the embodiments of the present invention are not limited thereto either.

[0104] As the smallest energy unit of the battery device, the battery cell includes a housing and an electrode assembly disposed in the housing. The electrode assembly is the component in the battery cell where an electrochemical reaction occurs. One or more electrode assemblies can be included in the housing. The electrode assembly is mainly formed by winding or laminating a positive electrode sheet and a negative electrode sheet, and a separator is usually disposed between the positive electrode sheet and the negative electrode sheet. The parts of the positive electrode sheet and the negative electrode sheet having active materials constitute the main body of the electrode assembly, and the parts of the positive electrode sheet and the negative electrode sheet without active materials respectively constitute the electrode tabs.

[0105] The positive electrode sheet can include a positive electrode current collector and a positive electrode film layer disposed on at least one surface of the positive electrode current collector, and the positive electrode film layer includes a positive electrode active material.

[0106] As an example, the positive electrode current collector has two surfaces opposite to each other in its own thickness direction, and the positive electrode film layer is disposed on any one or both of the two opposite surfaces of the positive electrode current collector.

[0107] As an example, the positive electrode current collector can be made of a metal foil or a composite current collector.

[0108] The negative electrode sheet can include a negative electrode current collector and a negative electrode film layer disposed on at least one surface of the negative electrode current collector, and the negative electrode film layer includes a negative electrode active material.

[0109] As an example, the negative electrode current collector has two surfaces opposite to each other in its own thickness direction, and the negative electrode film layer is disposed on any one or both of the two opposite surfaces of the negative electrode current collector.

[0110] As an example, the negative electrode current collector can be made of a metal foil, a foam metal or a composite current collector.

[0111] At present, from the perspective of market development, the application of batteries is becoming more and more extensive. Batteries are not only used in energy storage power systems such as hydropower, thermal power, wind power and solar power stations, but also widely used in electric vehicles such as electric bicycles, electric motorcycles, electric cars, as well as aerospace and other fields. With the continuous expansion of the application field of power batteries, the market demand is also constantly expanding.

[0112] In the related art, in order to further improve the energy density of the battery cell, the adapter for connecting the tab and the electrode terminal is omitted, and the tab of the electrode assembly is directly connected to the electrode terminal on the shell of the battery cell without an adapter. The connection process of the tab of the electrode assembly and the electrode terminal is as follows: firstly, the multi-layer tab sheet is pre-welded by ultrasonic so that the multi-layer tab sheet is welded and connected to form an integral tab, and then the tab and the electrode terminal are connected by laser welding.

[0113] However, in the related art, the process of laser welding the tabs and electrode terminals is prone to welding defects such as explosion points and collapse, and it is easy to produce many welding defects such as cracks on the tabs. The welding quality of the laser welding process is poor, which affects the service stability of the battery. Therefore, how to improve the laser welding quality of the tabs and electrode terminals and improve the service stability of the battery is a technical problem that needs to be solved urgently.

[0114] Based on this, the present invention proposes an ultrasonic welding head, which includes: a welding head body, a first welding tooth structure and a second welding tooth structure. The welding head body has a welding surface, the first welding tooth structure is convexly arranged on the welding surface, the second welding tooth structure is convexly arranged on a side of the first welding tooth structure away from the welding surface, and the second welding tooth structure includes at least one second welding tooth, and the second welding tooth extends in a long strip shape in the extension direction of the welding surface.

[0115] In the above ultrasonic welding head, by adding a second tooth structure on the side of the first tooth structure of the ultrasonic welding head away from the welding surface, multi-stage upsetting can be performed on multi-layer foils, the compaction effect of the overall welding of the multi-layer foils by the first tooth structure and the second tooth structure can be enhanced, the gap between the multi-layer foils can be reduced, which helps to improve the welding quality of subsequent welding processes. For example, when the subsequent welding process is a laser welding process, welding defects such as blowholes and collapses generated during the laser welding process can be reduced, and welding cracks can also be reduced. And because the gap between the multi-layer foils is reduced, it is beneficial to improve the heat dissipation uniformity of the laser welding joint, thus helping to improve the problem of foil cracking caused by excessive local stress of the foil. And, by setting the second tooth to extend in a strip shape in the extending direction of the welding surface, the contact length between the second tooth structure and the surface of the multi-layer foils can be increased, further enhancing the compaction effect between the multi-layer foils, so that the gap between the multi-layer foils can be further reduced, which is more helpful to improve the welding quality of subsequent welding processes. For example, when the subsequent welding process is a laser welding process, since the compaction between the multi-layer foils at the weld mark position corresponding to the second tooth is tighter and the gap is smaller, laser welding can be performed at the weld mark position corresponding to the second tooth, which can better reduce laser welding defects and better improve the laser welding quality. When the ultrasonic welding head is used to weld the multi-layer foils of the tab, it helps to improve the subsequent laser welding quality between the tab and the electrode terminal, which is beneficial to improving the service stability of the battery.

[0116] The battery device disclosed in the embodiment of the present invention can be used in an electrical device using the battery device as a power source or various energy storage systems using the battery device as an energy storage element. In addition to being used in vehicles, the battery device can also be used in, but not limited to, mobile phones, tablets, laptop computers, electric toys, power tools, battery cars, electric vehicles, ships, spacecraft, and so on. Among them, the electric toy can include fixed or mobile electric toys, such as game consoles, electric vehicle toys, electric ship toys, and electric aircraft toys, etc. The spacecraft can include airplanes, rockets, space shuttles, and spaceships, etc.

[0117] The electrical device disclosed in the embodiment of the present invention can be a fuel vehicle, a gas vehicle, or a new energy vehicle. The new energy vehicle can be a pure electric vehicle, a hybrid electric vehicle, or an extended-range electric vehicle, etc. The battery device is arranged inside the vehicle, and the battery device can be arranged at the bottom, head, or tail of the vehicle. The battery device can be used for power supply of the vehicle. For example, the battery device can be used as the operating power source of the vehicle. The vehicle can also include a controller and a motor. The controller is used to control the battery device to supply power to the motor. For example, it is used for the working power requirements during the start, navigation, and driving of the vehicle. In some embodiments of the present invention, the battery device can not only be used as the operating power source of the vehicle, but also be used as the driving power source of the vehicle, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle.

[0118] Reference is made below Figures 1-9 to describe the ultrasonic welding head 100 according to an embodiment of the present invention.

[0119] Reference Figures 1-3 , in a first aspect, the present invention provides an ultrasonic welding head 100, comprising: a welding head body 10, a first welding tooth structure 20 and a second welding tooth structure 30. The welding head body 10 has a welding surface 11, the first welding tooth structure 20 protrudes from the welding surface 11, the second welding tooth structure 30 protrudes from a side of the first welding tooth structure away from the welding surface 11, the second welding tooth structure 30 includes at least one second welding tooth 31, and the second welding tooth 31 extends in a strip shape in the extending direction of the welding surface 11.

[0120] The ultrasonic welding head 100 is the part in the welded part that contacts the multi-layer foil during the welding process of the ultrasonic welding device. Usually, the high-frequency vibration energy generated by the transducer is adjusted in amplitude through the horn and finally transmitted to the ultrasonic welding head 100. The ultrasonic welding head 100 then concentrates the received vibration energy on the bonding part of the multi-layer foil. Under the condition of applying pressure, it is converted into heat energy through friction to weld the welding parts together.

[0121] Among them, the welding head body 10 has a welding surface 11, and the welding surface 11 can be a plane where the welding head body 10 contacts the multi-layer foil. For example, the welding head body 10 can be made of materials with good thermal conductivity and corrosion resistance such as aluminum alloy, titanium alloy or stainless steel.

[0122] The first welding tooth structure 20 protruding from the welding surface 11 means that the first welding tooth structure 20 is provided on the welding surface 11 and protrudes relative to the welding surface 11.

[0123] The first welding tooth structure 20 is provided on the welding surface 11. The first welding tooth 21 can effectively transmit the vibration energy to the welding part, and at the same time transmit the pressure and amplitude. Under the condition of applying pressure, it is converted into heat energy through friction to weld the welding parts together.

[0124] The second welding tooth structure 30 protrudes from a side of the first welding tooth structure away from the welding surface 11. The second welding tooth structure 30 compacts the multi-layer foil during ultrasonic welding of the multi-layer foil, reduces the gap between the multi-layer foils, and improves the quality of the subsequent welding process. If there is still a gap between the multi-layer foils after ultrasonic welding, it will cause uneven heat dissipation problems in the subsequent welding process, resulting in excessive local pressure on the multi-layer foils and cracking.

[0125] For example, the direction in which the first welding tooth structure protrudes from the welding surface 11 can refer to the e3 direction in the figure.

[0126] The second welding tooth structure 30 includes at least one second welding tooth 31. It can be that the second welding tooth structure 30 includes one second welding tooth 31, or it can be that the second welding tooth structure 30 includes multiple second welding teeth 31. By making the second welding tooth structure 30 include at least one second welding tooth 31 and making the second welding tooth 31 extend in a strip shape in the extending direction of the welding surface 11, the contact length between the second welding tooth structure 30 and the surface of the multi-layer foil is longer, enhancing the compaction effect of the second welding tooth structure 30 on the surface of the multi-layer foil.

[0127] In the above technical solution, by adding the second welding tooth structure 30 on the side of the first welding tooth structure 20 of the ultrasonic welding head 100 away from the welding surface 11, multi-stage upsetting can be performed on the multi-layer foil, the compaction effect of the overall first welding tooth structure 20 and second welding tooth structure 30 on the welding of the multi-layer foil can be enhanced, the gap between the multi-layer foils can be reduced, which helps to improve the welding quality of the subsequent welding process. For example, when the subsequent welding process is a laser welding process, welding defects such as blowholes and collapses generated during the laser welding process can be reduced, and welding cracks can also be reduced. And because the gap between the multi-layer foils is reduced, it is beneficial to improve the heat dissipation uniformity of the laser welding joint, thus being beneficial to improving the problem of foil cracking caused by excessive local stress of the foil; moreover, by setting the second welding tooth 31 to extend in a strip shape in the extending direction of the welding surface 11, the contact length between the second welding tooth structure 30 and the surface of the multi-layer foil can be increased, further enhancing the compaction effect between the multi-layer foils, thereby further reducing the gap between the multi-layer foils, and more helping to improve the welding quality of the subsequent welding process. For example, when the subsequent welding process is a laser welding process, since the compaction between the multi-layer foils at the weld mark position corresponding to the second welding tooth 31 is tighter and the gap is smaller, laser welding can be performed at the weld mark position corresponding to the second welding tooth 31, which can better reduce laser welding defects and better improve the laser welding quality. When the ultrasonic welding head 100 is used to weld the multi-layer foil of the tab 42, it helps to improve the subsequent laser welding quality between the tab 42 and the electrode terminal 401, and is beneficial to improving the service stability of the battery.

[0128] Reference Figures 1-5 , in some embodiments, both ends in the length direction of the second welding tooth 31 respectively extend to the opposite ends of the welding surface 11.

[0129] For example, both ends in the length direction of the second welding tooth 31 can respectively extend to both ends in the length direction of the welding surface 11.

[0130] In the above technical solution, by extending both ends of the second welding tooth 31 in the length direction to the opposite ends of the welding surface 11, the length of the second welding tooth 31 can be increased. During ultrasonic welding, the contact length between the second welding tooth structure 30 and the surface of the multi-layer foil is relatively long, further enhancing the compaction effect of the second welding tooth structure 30 on the multi-layer foil; moreover, since the length of the second welding tooth 31 is relatively long, the weld mark corresponding to the second welding tooth 31 is relatively long. In this way, when laser welding is performed on the weld mark position corresponding to the second welding tooth 31 in the subsequent welding process, the length of the laser welding can be relatively long, which is beneficial to improving the reliability and stability of the subsequent welding connection. For example, after the ultrasonic welding head 100 is used to weld the multi-layer foil of the tab 42, when the subsequent welding process is a laser welding process, the laser weld between the tab 42 and the electrode terminal 401 can be relatively long, which helps to improve the stability and reliability of the welded connection between the tab 42 and the electrode terminal 401.

[0131] Reference Figures 2-3 , in some embodiments, the second welding tooth 31 extends along the length direction of the welding surface 11.

[0132] For example, the welding surface 11 can be rectangular.

[0133] For example, the length direction of the welding surface 11 can refer to the e1 direction in the attached drawing.

[0134] In the above technical solution, by making the second welding tooth 31 extend along the length direction of the welding surface 11, the space in the length direction of the welding surface 11 can be utilized, and the length of the second welding tooth 31 can be increased. During ultrasonic welding, the contact length between the second welding tooth structure 30 and the surface of the multi-layer foil is relatively long, enhancing the compaction effect of the second welding tooth structure 30 on the multi-layer foil.

[0135] Reference Figures 2-3 , in some embodiments, the second welding tooth 31 extends along the width direction of the welding surface 11.

[0136] For example, the welding surface 11 can be rectangular.

[0137] For example, the width direction of the welding surface 11 can refer to the e2 direction in the attached drawing.

[0138] In the above technical solution, by making the second welding tooth 31 extend along the width direction of the welding surface 11, the space in the width direction of the welding surface 11 can be utilized, and it is also beneficial to increase the arrangement quantity of the second welding teeth 31. During ultrasonic welding, the contact area between the second welding tooth structure 30 and the surface of the multi-layer foil is relatively large, enhancing the compaction effect of the second welding tooth structure 30 on the multi-layer foil.

[0139] ReferenceFigures 2-3 , in some embodiments, the second welding teeth 31 extend along a straight line.

[0140] In the above technical solution, by setting the second welding teeth 31 that extend along a straight line, the structure of the second welding teeth 31 can be simplified, which is convenient for processing and forming; moreover, the welding marks corresponding to the second welding teeth 31 that extend along a straight line also basically extend along a straight line. In this way, in the subsequent welding process, welding connections can be made along a straight line, making the design of the subsequent welding process relatively simple.

[0141] Reference Figures 2-3 , in some embodiments, there are multiple second welding teeth 31 arranged at intervals.

[0142] For example, the second welding teeth 31 can be two, three, four, etc. arranged at intervals.

[0143] In the above technical solution, by setting multiple second welding teeth 31 arranged at intervals, the multiple second welding teeth 31 can compact multiple different positions of multiple multi-layer foils, so that the gaps at multiple different positions of the multi-layer foils can be reduced, which helps to improve the quality of the subsequent welding process.

[0144] Reference Figures 2-3 , in some embodiments, the multiple second welding teeth 31 are arranged side by side along the width direction of the second welding teeth 31.

[0145] Among them, the width direction of the second welding teeth 31 is perpendicular to the extending direction of the second welding teeth 31.

[0146] In the above technical solution, by arranging the multiple second welding teeth 31 side by side along the width direction of the second welding teeth 31, the contact area between the second welding tooth structure 30 and the surface of the multi-layer foil can be increased, and the compaction effect between the multi-layer foils can be enhanced. Thus, the gaps at different positions in the width direction of the second welding teeth 31 of the multi-layer foils can be reduced, which helps to improve the quality of the subsequent welding process.

[0147] Reference Figures 2-3 , in some embodiments, the second welding teeth 31 extend along the length direction of the welding surface 11, and the multiple second welding teeth 31 are arranged along the width direction of the welding surface 11.

[0148] In the above technical solution, by extending the second welding teeth 31 along the length direction of the welding surface 11, the space in the length direction of the welding surface 11 can be fully utilized, so that the extension length of the second welding teeth 31 is relatively long, and a plurality of second welding teeth 31 are arranged along the width direction of the welding surface 11, and the distribution of the plurality of second welding teeth 31 is relatively uniform, which can increase the contact length and contact area between the second welding teeth structure 30 and the surface of the multi-layer foil, make the contact between the second welding teeth structure 30 and the surface of the multi-layer foil relatively uniform, and make the heat between the multi-layer foils more evenly distributed, and can enhance the compaction effect between the multi-layer foils.

[0149] Reference Figure 2 , in some embodiments, in the arrangement direction of the plurality of second welding teeth 31, the distance between two adjacent second welding teeth 31 is d1, and the maximum width of the second welding teeth 31 is W2, and W2 < d1.

[0150] In the direction in which the second welding teeth 31 protrude from the welding surface 11, when the width of the second welding teeth 31 is consistent, the width of the second welding teeth 31 is the maximum width of the second welding teeth 31. In the direction in which the second welding teeth 31 protrude from the welding surface 11, when the width of the second welding teeth 31 changes, the width at the maximum width of the second welding teeth 31 is the maximum width of the second welding teeth 31.

[0151] In the above technical solution, by making the maximum width W2 of the second welding teeth 31 less than the distance d1 between two adjacent second welding teeth 31, the width of the second welding teeth 31 can be made smaller, and under a certain welding pressure, the second welding teeth 31 can generate a larger pressure on the multi-layer foil, further enhancing the compaction effect of the second welding teeth 31 on the multi-layer foil.

[0152] Reference Figure 2 , in some embodiments, the ratio range of W2 to d1 is 0.2 to 0.8.

[0153] For example, the ratio of the maximum width W2 of the second welding teeth 31 to the distance d1 between two adjacent second welding teeth 31 can be 0.2, 0.4, 0.6, 0.8, etc.

[0154] In the above technical solution, by setting the ratio of the maximum width W2 of the second welding teeth 31 to the distance d1 between two adjacent second welding teeth 31 within the range of 0.2 to 0.8, it is possible to generate a larger pressure on the multi-layer foil under a certain welding pressure while making the contact area between the second welding teeth structure 30 and the surface of the multi-layer foil larger, and enhancing the compaction effect between the multi-layer foils.

[0155] Reference Figure 2, in some embodiments, in the arrangement direction of the plurality of second welding teeth 31, the minimum distance between the second welding teeth 31 and the edge of the welding surface 11 is d2, the width of the second welding teeth 31 is W2, and d2 > W2.

[0156] In the above technical solution, by making the minimum distance d2 between the second welding teeth 31 and the edge of the welding surface 11 greater than the maximum width W2 of the second welding teeth 31, a certain distance can be provided between the second welding teeth 31 and the edge of the welding surface 11, enabling the second welding teeth 31 to better compact the multi-layer foil, thereby enhancing the compaction effect between the multi-layer foils.

[0157] Reference Figure 7 , in some embodiments, the cross-section of the second welding teeth 31 is a second cross-section, the second cross-section has a tapered portion, and the tapered portion extends to the side of the second welding teeth 31 away from the welding surface 11. In the direction from the welding surface 11 to the second welding teeth 31, the width of the tapered portion gradually decreases.

[0158] Wherein, the cross-section obtained by cutting the second welding teeth 31 with a plane perpendicular to the length direction of the second welding teeth 31 is the cross-section of the second welding teeth 31.

[0159] The width of the tapered portion refers to the dimension of the tapered portion in the width direction of the second welding teeth 31.

[0160] It can be that part of the second welding teeth 31 forms the tapered portion, or the entire second welding teeth 31 forms the tapered portion.

[0161] In the above technical solution, by making the width of the tapered portion of the second welding teeth 31 gradually decrease in the direction from the welding surface 11 to the second welding teeth 31, under a certain welding pressure, the second welding teeth 31 can have a greater pressure on the multi-layer foil, thereby enhancing the compaction effect between the second welding teeth 31 and the multi-layer foils.

[0162] Reference Figures 2-7 , in some embodiments, in the extending direction of the second welding teeth 31, the cross-sectional areas of at least part of the second welding teeth 31 are the same.

[0163] The cross-section obtained by cutting the second welding teeth 31 with a plane perpendicular to the length direction of the second welding teeth 31 is the cross-section of the second welding teeth 31.

[0164] For example, in the extending direction of the second welding teeth 31, it can be that the cross-sectional areas of part of the second welding teeth 31 are the same, or the cross-sectional areas of all of the second welding teeth 31 are the same.

[0165] In the above technical solution, by making the cross-sectional areas of at least part of the second welding teeth 31 in the extending direction the same, it is possible to keep the compaction of the second welding teeth 31 on the multi-layer foil in the extending direction relatively uniform, thereby enhancing the compaction effect of the second welding teeth 31 on the multi-layer foil, and the width dimensions of the weld imprints corresponding to the second welding teeth 31 in their extending direction are relatively uniform, facilitating the subsequent welding connection operation at the weld imprints corresponding to the second welding teeth 31.

[0166] Reference Figure 7 , in some embodiments, the cross-section of the second welding teeth 31 is arcuate, circular or elliptical.

[0167] For example, the cross-section of the second welding teeth 31 can be one of arcuate, circular or elliptical.

[0168] In the above technical solution, by setting the cross-section of the second welding teeth 31 to shapes such as arcuate, circular or elliptical, it is possible to prevent the surface of the second welding teeth 31 from scratching the foil when contacting the multi-layer foil.

[0169] Reference Figure 2 , in some embodiments, the second welding teeth 31 include one tooth part.

[0170] For example, the second welding teeth 31 including one tooth part can be the second tooth part formed by the second welding teeth 31 themselves.

[0171] In the above technical solution, by making the second welding teeth 31 include one tooth part, the structure of the second welding teeth 31 can be simple and convenient for processing and forming.

[0172] Reference Figures 2-7 , in some embodiments, the second welding teeth 31 include multiple tooth parts. The surfaces of the tooth parts on the side away from the welding surface 11 constitute the tooth part end faces 12. The multiple tooth parts are respectively the first tooth part to the mth tooth part arranged in sequence along the protruding direction of the second welding teeth 31. The nth tooth part is arranged on the tooth part end face 12 of the (n - 1)th tooth part, and the projection of the nth tooth part on the tooth part end face 12 of the (n - 1)th tooth part is located within the tooth part end face 12 of the (n - 1)th tooth part, where 2 ≤ n ≤ m.

[0173] For example, the value of n can be 2, 3, 4, 5, etc., and the value of m can be 2, 3, 4, 5, etc., and 2 ≤ n ≤ m is satisfied.

[0174] In the above technical solution, by setting the second welding tooth 31 to include a plurality of tooth parts, and the plurality of tooth parts are respectively the first tooth part to the m-th tooth part arranged in sequence along the protruding direction of the second welding tooth 31, the n-th tooth part is arranged on the tooth end face 12 of the (n - 1)-th tooth part, and the projection of the n-th tooth part on the tooth end face 12 of the (n - 1)-th tooth part is located within the tooth end face 12 of the (n - 1)-th tooth part, so that the part of the tooth end face 12 of the (n - 1)-th tooth part on the side away from the welding surface 11 that exceeds the n-th tooth part can form a welding pier pressing surface. Thus, when the ultrasonic welding head 100 welds the welding material, each tooth part can compact and pier the multi-layer foil materials, so as to realize multi-layer pressing and compaction of the welding material, further enhance the compaction effect between the multi-layer foil materials, better reduce the gap between the multi-layer foil materials, and further reduce the welding energy loss and the influence on the subsequent welding process easily caused by the too large inter-layer gap of the multi-layer foil materials, which helps to better improve the welding quality of the subsequent welding process.

[0175] Reference Figures 2-3 , in some embodiments, the first welding tooth structure 20 includes a first welding tooth 21, the surface of the first welding tooth 21 on the side away from the welding surface 11 constitutes a tooth end face 22, the second welding tooth 31 is arranged on the tooth end face 22, and the projection of the second welding tooth 31 on the tooth end face 22 is located within the tooth end face 22.

[0176] In the above technical solution, by arranging the second welding tooth 31 within the tooth end face 22 of the first welding tooth 21, this can make a distinct boundary between the second welding tooth 31 and the first welding tooth 21, which is more conducive to forming a multi-stage welding tooth structure between the first welding tooth 21 and the second welding tooth 31, and is more conducive to realizing multi-stage pressing of the multi-layer foil materials, with a better compaction effect.

[0177] Reference Figure 5 , in some embodiments, in the protruding direction of the first welding tooth 21 relative to the welding surface 11, the tooth height of the first welding tooth 21 is h1, the tooth height of the second welding tooth 31 is h2, and the ratio range of h2 to h1 is 0.3 - 0.8.

[0178] Among them, the protruding direction of the first welding tooth 21 relative to the welding surface 11 can refer to the e3 direction in the attached drawing.

[0179] For example, the ratio of h2 to h1 can be 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, etc.

[0180] In the above technical solution, by making the ratio of the tooth height h2 of the second welding tooth 31 to the tooth height h1 of the first welding tooth 21 not less than 0.3, the second welding tooth 31 can have a relatively high tooth height, so that the second welding tooth 31 has a better compaction effect on the multi-layer foil; and by making the ratio of the tooth height h2 of the second welding tooth 31 to the tooth height h1 of the first welding tooth 21 not greater than 0.8, it can be ensured that the second welding tooth 31 will not affect the welding effect of the first welding tooth 21 due to excessive tooth height. In this way, it can be better avoided that the contact between the first welding tooth 21 and the multi-layer foil is affected due to the excessive tooth height of the second welding tooth 31. Therefore, when the ultrasonic welding head 100 welds the multi-layer foil, the first welding tooth 21 and the second welding tooth 31 can both fully contact the multi-layer foil, resulting in a relatively large contact area between the first welding tooth 21 and the second welding tooth 31 and the multi-layer foil, and the compaction effect on the multi-layer foil can be improved.

[0181] Reference Figure 5 , in some embodiments, in the protruding direction of the first welding tooth 21 relative to the welding surface 11, the tooth height of the first welding tooth 21 is h1, and the value range of h1 is 0.2 mm to 0.6 mm.

[0182] For example, the tooth height h1 of the first welding tooth 21 can be 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, etc.

[0183] In the above technical solution, by making the tooth height h2 of the second welding tooth 31 not less than 0.2 mm, the second welding tooth 31 can have a relatively high tooth height, so that the second welding tooth 31 has a better compaction effect on the multi-layer foil; and by making the tooth height h2 of the second welding tooth 31 not greater than 0.6 mm, it can be ensured that the second welding tooth 31 will not affect the welding effect of the first welding tooth 21 due to excessive tooth height. In this way, it can be better avoided that the contact between the first welding tooth 21 and the multi-layer foil is affected due to the excessive tooth height of the second welding tooth 31. Therefore, when the ultrasonic welding head 100 welds the multi-layer foil, the first welding tooth 21 and the second welding tooth 31 can both fully contact the multi-layer foil, resulting in a relatively large contact area between the first welding tooth 21 and the second welding tooth 31 and the multi-layer foil, and the compaction effect on the multi-layer foil can be improved.

[0184] Reference Figure 2 , in some embodiments, the tooth end surface 22 of the welding tooth is a flat surface.

[0185] In the above technical solution, by setting the tooth end surface 22 of the first welding tooth 21 as a flat surface, the contact area between the first welding tooth 21 and the multi-layer foil can be increased, and the compaction area for the multi-layer foil can be increased, which is beneficial to improving the compaction effect on the multi-layer foil.

[0186] Reference Figures 2-3, in some embodiments, the first solder tooth structure 20 includes a third solder tooth 23, and the third solder tooth 23 is disposed between adjacent first solder teeth 21.

[0187] For example, the third solder tooth 23 is located between adjacent first solder teeth 21, and it can be that the third solder tooth 23 is located in the middle of two adjacent first solder teeth 21.

[0188] In the above technical solution, by disposing the third solder tooth 23 between adjacent first solder teeth 21, the portion of the multi-layer foil between adjacent first solder teeth 21 can be compacted by the third solder tooth 23, so that the multi-layer foil is more evenly compacted, which is beneficial to improving the welding quality of subsequent welding processes.

[0189] Reference Figures 2-3 , in some embodiments, the first solder tooth structure 20 includes a fourth solder tooth 24, and the fourth solder tooth 24 is disposed between the first solder tooth 21 and the edge of the welding surface 11.

[0190] For example, the fourth solder tooth 24 can be disposed between the first solder tooth 21 and the edge of the welding surface 11 extending along the length direction of the welding surface 11.

[0191] In the above technical solution, by disposing the fourth solder tooth 24 between the first solder tooth 21 and the edge of the welding surface 11, the portion of the multi-layer foil between the first solder tooth 21 and the edge of the welding surface 11 can be compacted by the fourth solder tooth 24, so that the multi-layer foil is more evenly compacted, which is beneficial to improving the welding quality of subsequent welding processes; moreover, the fourth solder tooth 24 can also reduce the situation that the edge of the first solder tooth 21 scratches the multi-layer foil.

[0192] Reference Figures 2-3 , in some embodiments, the first solder tooth 21 includes a solder tooth main body 211 and a plurality of solder tooth branches 212. The solder tooth main body 211 extends in a long strip shape in the extending direction of the welding surface 11, and the plurality of solder tooth branches 212 are connected to at least one side in the width direction of the solder tooth main body 211. The second solder tooth 31 is disposed on the solder tooth main body 211 and is consistent with the extending direction of the solder tooth main body 211.

[0193] For example, the first solder tooth 21 can include two, three, four, five or other multiple solder tooth branches 212.

[0194] The plurality of solder tooth branches 212 are connected to at least one side in the width direction of the solder tooth main body 211, and it can be that the plurality of solder tooth branches 212 are connected to one side in the width direction of the solder tooth main body 211, or the plurality of solder tooth branches 212 are connected to both sides in the width direction of the solder tooth main body 211.

[0195] In the above technical solution, by setting the first welding tooth 21 to include a welding tooth main body 211 and a plurality of welding tooth branches 212, and connecting the plurality of welding tooth branches 212 to at least one side in the width direction of the welding tooth main body 211, the contact area between the first welding tooth 21 and the multi-layer foil can be increased, which is beneficial to enhancing the compaction uniformity and compaction effect on the multi-layer foil. By arranging the second welding tooth 31 on the welding tooth main body 211 and in the same extension direction as the welding tooth main body 211, the contact length between the second welding tooth structure 30 and the surface of the multi-layer foil is increased, and the compaction effect of the second welding tooth 31 on the multi-layer foil is enhanced.

[0196] Reference Figure 2 , in some embodiments, the width of the second welding tooth 31 is W2, and the width of the welding tooth main body 211 is W1, and W2 ≤ W1.

[0197] For example, the width direction of the second welding tooth 31 and the width direction of the welding tooth main body 211 may refer to the e2 direction in the attached drawing.

[0198] In the above technical solution, by making the width W2 of the second welding tooth 31 less than or equal to the width W1 of the welding tooth main body 211, the width of the welding tooth main body 211 of the first welding tooth 21 can be made larger, which can provide a sufficient support area for the second welding tooth 31, and make the contact area between the first welding tooth 21 and the multi-layer foil larger, and can further enhance the compaction effect of the second welding tooth 31 on the multi-layer foil.

[0199] Reference Figure 2 , in some embodiments, the ratio range of W2 to W1 is 0.5 to 0.9.

[0200] For example, the ratio of the width W2 of the second welding tooth 31 to the width W1 of the welding tooth main body 211 can be 0.5, 0.7, 0.9, etc.

[0201] In the above technical solution, by making the ratio of the width W2 of the second welding tooth 31 to the width W1 of the welding tooth main body 211 not less than 0.5, the contact area between the second welding tooth 31 and the multi-layer foil can be made larger, the compaction range can be larger, and the compaction effect can be better. And by making the ratio of the width W2 of the second welding tooth 31 to the width W1 of the welding tooth main body 211 not greater than 0.9, a multi-stage welding tooth structure can be better formed between the second welding tooth 31 and the first welding tooth 21, which is more conducive to realizing multi-stage upsetting of the multi-layer foil and has a better compaction effect.

[0202] Reference Figures 2-3, in some embodiments, the first solder tooth structure 20 includes a third solder tooth 23. A plurality of receiving grooves 13 are defined between two adjacent first solder teeth 21. The plurality of receiving grooves 13 are arranged at intervals along the extending direction of the solder tooth body 211. The solder tooth branch 212 is located between two adjacent receiving grooves 13, and the third solder tooth 23 is located in the receiving groove 13.

[0203] For example, each receiving groove 13 may accommodate a third solder tooth 23, or some of the receiving grooves 13 may accommodate a third solder tooth 23.

[0204] In the above technical solution, by defining a plurality of receiving grooves 13 between two adjacent first solder teeth 21, the plurality of receiving grooves 13 are arranged at intervals along the extending direction of the solder tooth body 211, and a third solder tooth 23 is arranged in the receiving groove 13, the contact area between the first solder tooth structure 20 and the multi-layer foil can be further increased, so that the portion of the multi-layer foil located between two adjacent first solder teeth 21 can be compacted by the third solder tooth 23, so that the multi-layer foil is compacted more evenly, which is beneficial to improving the welding quality of subsequent welding processes.

[0205] Reference Figures 2-3 , in some embodiments, the third solder tooth 23 is in the shape of a frustum of a pyramid.

[0206] In the above technical solution, by making the third solder tooth 23 in the shape of a frustum of a pyramid, the third solder tooth 23 can have a larger contact area with the multi-layer foil and a better compaction effect, and a welding pier pressing surface can be formed on the contact surface between the third solder tooth 23 and the multi-layer foil, providing a larger heat transfer area, which is beneficial to reducing welding cracks caused by local stress concentration of the multi-layer foil.

[0207] Reference Figures 2-3 , in some embodiments, the first solder tooth structure 20 includes a fourth solder tooth 24. The fourth solder tooth 24 is arranged between the first solder tooth 21 and the edge of the welding surface 11. There are a plurality of fourth solder teeth 24, and the plurality of fourth solder teeth 24 located on the same side of the first solder tooth 21 are arranged at intervals along the extending direction of the solder tooth body 211.

[0208] In the above technical solution, by arranging the fourth solder tooth 24 between the first solder tooth 21 and the edge of the welding surface 11, the portion of the multi-layer foil located between the first solder tooth 21 and the edge of the welding surface 11 can be compacted by the fourth solder tooth 24, so that the multi-layer foil is compacted more evenly, which is beneficial to improving the welding quality of subsequent welding processes; moreover, the fourth solder tooth 24 can also reduce the situation that the edge of the first solder tooth 21 scratches the multi-layer foil; and by arranging the fourth solder teeth 24 at intervals along the extending direction of the solder tooth body 211, the fourth solder teeth 24 compact the multi-layer foil more evenly and have a better compaction effect.

[0209] ReferenceFigures 1-7 Second, the present invention provides an ultrasonic welding device, including: an ultrasonic welding head 100 according to the embodiment of the first aspect.

[0210] In the above technical solution, by providing the above ultrasonic welding head 100, and by adding a second tooth structure 30 on the side of the first tooth structure 20 of the ultrasonic welding head 100 away from the welding surface 11, multi-stage upsetting can be performed on multi-layer foils, the compaction effect of the overall welding of the first tooth structure 20 and the second tooth structure 30 on the multi-layer foils can be enhanced, the gap between the multi-layer foils can be reduced, which helps to improve the welding quality of subsequent welding processes. For example, when the subsequent welding process is a laser welding process, welding defects such as blowholes and collapses generated during the laser welding process can be reduced, welding cracks can also be reduced, and since the gap between the multi-layer foils is reduced, it is beneficial to improve the heat dissipation uniformity of the laser welding joint, thereby being beneficial to improving the problem of foil cracking caused by excessive local stress of the foil; and, by setting the second teeth 31 to extend in a long strip shape in the extending direction of the welding surface 11, the contact length between the second tooth structure 30 and the surface of the multi-layer foils can be increased, further enhancing the compaction effect between the multi-layer foils, thereby further reducing the gap between the multi-layer foils, and more helping to improve the welding quality of subsequent welding processes. For example, when the subsequent welding process is a laser welding process, since the compaction between the multi-layer foils at the weld mark position corresponding to the second teeth 31 is tighter and the gap is smaller, laser welding can be performed at the weld mark position corresponding to the second teeth 31, which can better reduce laser welding defects and better improve the laser welding quality. When the ultrasonic welding head 100 is used to weld the multi-layer foils of the tab 42, it helps to improve the subsequent laser welding quality between the tab 42 and the electrode terminal 401, and is beneficial to improving the service stability of the battery.

[0211] Reference Figure 8 Third, the present invention provides a method for detecting the wear of an ultrasonic welding head 100. The ultrasonic welding head 100 is the ultrasonic welding head 100 according to the embodiment of the first aspect. The method for detecting the wear of the ultrasonic welding head 100 includes: Performing ultrasonic pre-welding on a workpiece sample by using the ultrasonic welding head 100, and the weld mark on the workpiece sample corresponding to the second teeth 31 is the second weld mark 45; Identifying the second weld mark 45 formed on the workpiece sample; Calculating the weld mark area of a single second weld mark 45; Judging the wear condition of the ultrasonic welding head 100 according to the weld mark area of a single second weld mark 45.

[0212] Wherein, the workpiece sample can be multi-layer foils.

[0213] Among them, the weld mark corresponding to the second welding tooth 31 on the workpiece sample is the second weld mark 45, and the shape and area of the second weld mark 45 depend on the shape and size of the second welding tooth 31. The weld mark area of the second weld mark 45 can reflect the wear condition of the second welding tooth 31, and thus can reflect the wear condition of the ultrasonic welding head 100.

[0214] For example, the second weld mark 45 formed on the workpiece sample can be identified manually or by a machine.

[0215] In the above technical solution, by calculating the single weld mark area of the second weld mark 45 corresponding to the second welding tooth 31 formed on the workpiece sample, the wear condition of the second welding tooth 31 in the ultrasonic welding head 100 can be judged more intuitively and accurately. Thus, the ultrasonic welding head 100 can be replaced in time or repaired, reducing the occurrence of poor multi-layer foil welding and poor compaction effect caused by the wear of the ultrasonic welding head 100, which affects the subsequent welding process, and helping to improve the compaction effect of the ultrasonic welding head 100 on the multi-layer foil.

[0216] In some embodiments, identifying the second weld mark 45 formed on the workpiece sample includes: Collecting the weld mark image on the side of the workpiece sample where the weld mark is formed; Identifying the second weld mark 45 in the weld mark image.

[0217] For example, the weld mark image on the side of the workpiece sample where the weld mark is formed can be collected by a camera. Among them, the camera can be a CCD camera.

[0218] For example, a calibration plate can be used to calibrate the camera to convert the camera pixels into actual distances; the second weld mark 45 in the weld mark image can be identified by the software find_circle tool.

[0219] In the above technical solution, by collecting the weld mark image on the side of the workpiece sample where the weld mark is formed and identifying the second weld mark 45 in the weld mark image, the second weld mark 45 can be conveniently identified and found.

[0220] In some embodiments, calculating the weld mark area of a single second weld mark 45 includes: Identifying the outer contour of a single second weld mark 45; Calculating the area of the figure enclosed by the outer contour of the second weld mark 45.

[0221] Among them, the area of the figure enclosed by the outer contour of the second weld mark 45 is the weld mark area of the second weld mark 45.

[0222] For example, the software uses the Distance_PP operator to calculate the area of the figure enclosed by the outer contour of the second weld mark 45.

[0223] In the above technical solution, by first identifying the outer contour of a single second weld mark 45 and then calculating the area of the figure enclosed by the outer contour of the second weld mark 45, the weld mark area of the second weld mark 45 can be conveniently calculated. The calculation method of the weld mark area is simple and the calculation result is relatively accurate.

[0224] In some embodiments, according to the weld mark area of a single second weld mark 45, the wear condition of the ultrasonic welding head 100 is judged, including: Judging the wear condition of the ultrasonic welding head 100 according to the ratio of the weld mark area of a single second weld mark 45 to the designed area of the single second weld mark 45.

[0225] Wherein, the designed area of a single second weld mark 45 refers to the weld mark area formed by the second welding tooth 31 on the foil material when the ultrasonic welding head 100 is first tried out. This weld mark area can be obtained by using the above calculation method.

[0226] Wherein, during the long-term use of the ultrasonic welding head 100, the second welding tooth 31 will be gradually worn, and the weld mark area of the second weld mark 45 corresponding to the second welding tooth 31 will also gradually decrease. According to the ratio relationship between the weld mark area of a single second weld mark 45 and the designed area of the single second weld mark 45, the wear condition of the second welding tooth 31 can be judged relatively accurately, and the wear degree of the ultrasonic welding head 100 can also be judged.

[0227] In the above technical solution, by the magnitude relationship of the ratio of the weld mark area of a single second weld mark 45 to the designed area of the single second weld mark 45, the reduced amount of the weld mark area of the current second weld mark 45 relative to the designed area of the second weld mark 45 can be obtained. The reduced amount of the weld mark area of the second weld mark 45 relative to the designed area of the second weld mark 45 can relatively intuitively reflect the wear condition of the second welding tooth 31, and thus can reflect the wear condition of the ultrasonic welding head 100, which helps to improve the accuracy of judging the wear condition of the ultrasonic welding head 100.

[0228] In some embodiments, judging the wear condition of the ultrasonic welding head 100 according to the ratio of the weld mark area of a single second weld mark 45 to the designed area of the single second weld mark 45 includes: The weld mark area of a single second weld mark 45 is Sx, and the designed area of a single second weld mark 45 is S0. When the ratio of Sx to S0 is less than 0.2, it is judged that the life of the ultrasonic welding head 100 has reached the end.

[0229] For example, when the ratio of Sx to S0 is 0.3, it is judged that the life of the ultrasonic welding head 100 has not reached the end and it can continue to be used; when the ratio of Sx to S0 is 0.18, it is judged that the life of the ultrasonic welding head 100 has reached the end and the continued use is stopped.

[0230] In the above technical solution, by determining whether the ratio of the welding mark area Sx of a single second welding mark 45 to the designed area S0 of the single second welding mark 45 is less than 0.2, it is possible to determine whether the life of the ultrasonic welding head 100 has reached, and it is possible to simply and accurately determine whether the ultrasonic welding head 100 should be replaced or repaired.

[0231] Reference Figure 9 Fourthly, the present invention provides a battery cell 40, including: a housing 41 and an electrode assembly 46. The housing 41 is provided with an electrode terminal 401. The electrode assembly 46 is disposed in the housing 41 and includes a tab 42. The tab 42 is connected to the electrode terminal 401. The tab 42 includes a plurality of tab pieces stacked and welded together. A welding mark area 43 is formed on the tab 42. The welding mark area 43 is formed by welding with the ultrasonic welding head 100 according to the embodiment of the first aspect of the present invention. The welding mark area 43 includes a first welding mark 44 and a second welding mark 45. Both the first welding mark 44 and the second welding mark 45 are formed in a groove structure. The second welding mark 45 is formed on the bottom wall of the first welding mark 44 and extends in a long strip shape.

[0232] The housing 41 of the battery cell 40 is usually at least partially made of a metal material. For example, the housing 41 can be an aluminum case or a steel case.

[0233] For example, a plurality of tab pieces can be welded by ultrasonic welding.

[0234] The welding mark area 43 includes a first welding mark 44 and a second welding mark 45. Both the first welding mark 44 and the second welding mark 45 are formed in a groove structure. The second welding mark 45 is formed on the bottom wall of the first welding mark 44 and extends in a long strip shape. By forming the first welding mark 44 and the second welding mark 45, it is possible to compact the multi-layer tab pieces, discharge the air between the multi-layer tab pieces, reduce the gap between the multi-layer tab pieces, and facilitate the subsequent connection between the tab 42 and the electrode terminal 401.

[0235] For example, the welding mark area 43 of the tab piece can be formed by welding a plurality of tab pieces with the ultrasonic welding head 100 according to the embodiment of the first aspect of the present application. At this time, the welding mark area 43 can correspond to the welding surface 11, the first welding mark 44 can correspond to the first welding tooth 21, and the second welding mark 45 can correspond to the second welding tooth 31. That is, during the welding process, the first welding tooth 21 of the ultrasonic welding head 100 can form the first welding mark 44 on the tab piece, and the second welding tooth 31 of the ultrasonic welding head 100 can form the second welding mark 45 on the tab piece.

[0236] In the above technical solution, by welding on the multi-layer tab pieces of the tab 42 to form the first weld mark 44 and the second weld mark 45 both of which are groove structures, during the welding process of the multi-layer tab pieces, the multi-layer tab pieces can be compacted, the air between the multi-layer tab pieces can be discharged, the gap between the multi-layer tab pieces is reduced, and problems such as explosion points, collapse, welding cracks, and tab piece cracking caused by the air between the multi-layer tab pieces in the subsequent welding process are reduced; by the second weld mark 45 being formed on the bottom wall of the first weld mark 44 and extending in a long strip shape, in this way, the second weld mark 45 and the first weld mark 44 can form a multi-stage weld mark structure and the length of the second weld mark 45 is relatively large. During the welding process of the multi-layer tab pieces, the compaction effect on the multi-layer tab pieces can be further enhanced, so that the gap between the multi-layer tab pieces can be further reduced, which is more helpful for improving the welding quality of the subsequent welding process. For example, when the subsequent welding process is a laser welding process, the compaction between the multi-layer tab pieces at the position of the second weld mark 45 is tighter and the gap is smaller. In this way, laser welding can be performed at the position of the second weld mark 45, which can better reduce laser welding defects, better improve the laser welding quality, help improve the laser welding quality between the subsequent tab 42 and the electrode terminal 401, and is beneficial to improving the service stability of the battery.

[0237] In some embodiments, the first weld mark 44 includes a weld mark main body and a plurality of weld mark branches. The weld mark main body is in a long strip shape, and the plurality of weld mark branches are connected to at least one side in the width direction of the weld mark main body. The second weld mark 45 is formed on the bottom wall of the weld mark main body and is consistent with the extending direction of the weld mark main body.

[0238] For example, the plurality of weld mark branches being connected to at least one side in the width direction of the weld mark main body may be that the plurality of weld mark branches are connected to one side in the width direction of the weld mark main body, or may be that the plurality of weld mark branches are connected to both sides in the width direction of the weld mark main body.

[0239] In the above technical solution, by making the first weld mark 44 on the tab piece include a weld mark main body and a plurality of weld mark branches, and making the weld mark main body in a long strip shape, the weld mark area and weld mark length of the first weld mark 44 can be increased, which is beneficial to enhancing the compaction uniformity and compaction effect on the multi-layer tab pieces. By forming the second weld mark 45 on the bottom wall of the weld mark main body and being consistent with the extending direction of the weld mark main body, the weld mark length and weld mark area of the second weld mark 45 can be increased, which is beneficial to enhancing the compaction effect of the second weld mark 45 on the multi-layer tab pieces.

[0240] Reference Figure 7 Referring to

[0241] For example, the third weld mark being located between adjacent first weld marks 44 may be that the third weld mark is located in the middle of two adjacent first weld marks 44.

[0242] In the above technical solution, by providing a third weld mark between adjacent first weld marks 44, the weld mark area can be further increased, so that the portion of the multi-layer tab between adjacent first weld marks 44 can be compacted by the third weld mark, thereby making the multi-layer tab more evenly compacted, which is beneficial to improving the welding quality of subsequent welding processes.

[0243] Reference Figure 7 , in some embodiments, the weld mark area 43 includes a fourth weld mark, and the fourth weld mark is located between the first weld mark 44 and the edge of the tab 42.

[0244] For example, the fourth weld mark can be provided between the first weld mark 44 and multiple edges of the tab 42.

[0245] In the above technical solution, by printing a fourth weld mark in the weld mark area 43 between the first weld mark 44 of the tab 42 and the edge of the tab 42, the portion of the multi-layer tab between the first weld mark 44 and the edge of the tab 42 can be compacted by the fourth weld mark, thereby making the multi-layer tab more evenly compacted, which is beneficial to improving the welding quality of subsequent welding processes.

[0246] In some embodiments, the multi-layer tabs of the tab 42 are connected by ultrasonic welding, and the tab 42 is connected to the electrode terminal 401 by laser welding to form a laser weld seam, and the laser weld seam and the second weld mark 45 are oppositely arranged in the stacking direction of the multi-layer tabs.

[0247] Among them, laser welding is an efficient and precise welding method that uses a laser beam with a high energy density as a heat source to connect workpieces by melting materials.

[0248] In the above technical solution, by ultrasonically welding the multi-layer tabs of the tab 42, the ultrasonic welding forms the above-mentioned weld mark area 43 on the tab 42, and the weld mark area 43 includes the above-mentioned first weld mark 44 and second weld mark 45. During ultrasonic welding, the multi-layer tabs can be compacted, reducing the gap between the multi-layer tabs, facilitating the laser welding connection between the tab 42 and the electrode terminal 401, reducing the occurrence of tab explosion points, collapse and other situations during laser welding, improving the laser welding quality between the tab 42 and the electrode terminal 401, and being beneficial to improving the service stability of the battery.

[0249] Reference Figure 10 , in a fifth aspect, the present invention provides a battery device 200, including: a box body 201 and a battery cell 40 according to the embodiment of the fourth aspect, and the battery cell 40 is arranged in the box body 201.

[0250] In the above technical solution, by providing the above battery cell 40, the first weld mark 44 and the second weld mark 45 which are both groove structures are formed by welding on the multi-layer tab pieces of the tab 42. During the welding process of the multi-layer tab pieces, the multi-layer tab pieces can be compacted, the air between the multi-layer tab pieces can be discharged, the gap between the multi-layer tab pieces is reduced, and problems such as explosion points, collapse, welding cracks, and tab piece cracking caused by the air between the multi-layer tab pieces in the subsequent welding process are reduced; the second weld mark 45 is formed on the bottom wall of the first weld mark 44 and extends in a long strip shape. In this way, the second weld mark 45 and the first weld mark 44 can form a multi-stage weld mark structure and the length of the second weld mark 45 is relatively large. During the welding process of the multi-layer tab pieces, the compaction effect on the multi-layer tab pieces can be further enhanced, so that the gap between the multi-layer tab pieces can be further reduced, which is more conducive to improving the welding quality of the subsequent welding process. For example, when the subsequent welding process is a laser welding process, the compaction between the multi-layer tab pieces at the position of the second weld mark 45 is tighter and the gap is smaller. In this way, laser welding can be performed at the position of the second weld mark 45, which can better reduce laser welding defects and better improve the laser welding quality, helping to improve the laser welding quality between the subsequent tab 42 and the electrode terminal 401, and being beneficial to improving the service stability of the battery.

[0251] Reference Figure 11 , in a sixth aspect, the present invention provides an electrical device 300, including the battery device 200 of the fifth aspect embodiment.

[0252] For example, the electrical device 300 can be a vehicle, and the battery device 200 can be installed at the bottom of the vehicle body 60.

[0253] In the above technical solution, by providing the above battery device 200, the battery cells 40 provided in the battery device 200 are welded on the multi-layer tab pieces of the tab 42 to form a first weld mark 44 and a second weld mark 45 that are both groove structures. During the welding process of the multi-layer tab pieces, the multi-layer tab pieces can be compacted, the air between the multi-layer tab pieces can be discharged, the gap between the multi-layer tab pieces is reduced, and problems such as explosion points, collapse, welding cracks, and tab piece cracking caused by the air between the multi-layer tab pieces in the subsequent welding process are reduced; the second weld mark 45 is formed on the bottom wall of the first weld mark 44 and extends in a long strip shape. In this way, the second weld mark 45 and the first weld mark 44 can form a multi-stage weld mark structure and the length of the second weld mark 45 is relatively large. During the welding process of the multi-layer tab pieces, the compaction effect on the multi-layer tab pieces can be further enhanced, so that the gap between the multi-layer tab pieces can be further reduced, which is more conducive to improving the welding quality of the subsequent welding process. For example, when the subsequent welding process is a laser welding process, the compaction between the multi-layer tab pieces at the position of the second weld mark 45 is tighter and the gap is smaller. In this way, laser welding can be performed at the position of the second weld mark 45, which can better reduce laser welding defects, better improve the laser welding quality, help improve the laser welding quality between the subsequent tab 42 and the electrode terminal 401, and is beneficial to improving the service stability of the battery.

[0254] The following refers to Figures 1-7 Describe the ultrasonic welding head 100 according to some embodiments of the present invention.

[0255] In this embodiment, the ultrasonic welding head 100 includes: a welding head body 10, a first welding tooth structure 20, and a second welding tooth structure 30.

[0256] The welding head body 10 has a welding surface 11. The first welding tooth structure 20 protrudes from the welding surface 11. The second welding tooth structure 30 protrudes from the side of the first welding tooth structure away from the welding surface 11. The second welding tooth structure 30 includes two second welding teeth 31 that are spaced apart and extend in a long strip shape in the extending direction of the welding surface 11. The two second welding teeth 31 are arranged side by side along the width direction of the second welding teeth 31. The two ends in the length direction of the second welding teeth 31 respectively extend to the opposite ends of the welding surface 11.

[0257] The first welding tooth structure 20 includes a first welding tooth 21, a third welding tooth 23, and a fourth welding tooth 24. Among them, the first welding tooth 21 includes a tooth main body 211 that extends in a long strip shape in the extending direction of the welding surface 11 and tooth branches 212 formed on both sides in the width direction of the tooth main body 211. The third welding tooth 23 is arranged between adjacent first welding teeth 21, and the fourth welding tooth 24 is arranged between the first welding tooth 21 and the edge of the welding surface 11.

[0258] A plurality of receiving grooves 13 are defined between two adjacent first welding teeth 21. The plurality of receiving grooves 13 are arranged at intervals along the extending direction of the welding tooth body 211. The welding tooth branch 212 is located between two adjacent receiving grooves 13. The third welding tooth 23 is located in the receiving groove 13 and is in the shape of a frustum of a pyramid.

[0259] The fourth welding teeth 24 are arranged between the first welding teeth 21 and the edge of the welding surface 11. The plurality of fourth welding teeth 24 are arranged at intervals along the extending direction of the welding tooth body 211.

[0260] One side surface of the first welding tooth 21 away from the welding surface 11 constitutes a flat welding tooth end surface 22. The second welding tooth 31 is arranged in the welding tooth end surface 22 and is consistent with the extending direction of the welding tooth body 211. The projection of the second welding tooth 31 in the welding tooth end surface 22 is located within the welding tooth end surface 22. The cross-section of the second welding tooth 31 is a second cross-section, and the second cross-section has a tapered portion. The tapered portion extends to the side of the second welding tooth 31 away from the welding surface 11. In the direction from the welding surface 11 to the second welding tooth 31, the width of the tapered portion gradually decreases. In the extending direction of the second welding tooth 31, the cross-sectional area of the second welding tooth 31 is the same, and the cross-section of the second welding tooth 31 is bow-shaped.

[0261] In the description of this specification, the descriptions with reference to terms such as "one embodiment", "some embodiments", "schematic embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0262] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the claims and their equivalents.

Claims

1. An ultrasonic welding head, characterized in that, Comprising: A soldering head body having a soldering surface; A first soldering tooth structure protruding from the soldering surface; A second soldering tooth structure protruding from a side of the first soldering tooth structure away from the soldering surface, the second soldering tooth structure including at least one second soldering tooth, and the second soldering tooth extending in a strip shape in an extending direction of the soldering surface.

2. The ultrasonic welding head according to claim 1, wherein, Two ends in a length direction of the second soldering tooth respectively extend to opposite ends of the soldering surface.

3. The ultrasonic welding head according to claim 1, wherein The second soldering tooth extends along a length direction or a width direction of the soldering surface.

4. The ultrasonic welding head according to claim 1, wherein The second soldering tooth extends in a straight line.

5. The ultrasonic welding head according to claim 1, characterized in that, The second soldering teeth are multiple and arranged at intervals.

6. The ultrasonic welding head according to claim 5, characterized in that, The multiple second soldering teeth are arranged side by side along a width direction of the second soldering tooth.

7. The ultrasonic welding head according to claim 6, wherein, The second soldering tooth extends along the length direction of the soldering surface, and the multiple second soldering teeth are arranged along the width direction of the soldering surface.

8. The ultrasonic welding head according to claim 6, wherein In a arranging direction of the multiple second soldering teeth, a distance between two adjacent second soldering teeth is d1, and a maximum width of the second soldering tooth is W2, and W2 < d1.

9. The ultrasonic welding head according to claim 8, wherein, A ratio range of W2 to d1 is 0.2 to 0.

8.

10. The ultrasonic welding head according to claim 6, characterized in that, In a arranging direction of the multiple second soldering teeth, a minimum distance between the second soldering tooth and an edge of the soldering surface is d2, and a maximum width of the second soldering tooth is W2, and d2 > W2.

11. The ultrasonic welding head according to claim 1, wherein, A cross-section of the second soldering tooth is a second cross-section, and the second cross-section has a tapered portion extending to a side of the second soldering tooth away from the soldering surface, and in a direction from the soldering surface to the second soldering tooth, a width of the tapered portion gradually decreases.

12. The ultrasonic welding head according to claim 1, wherein, In an extending direction of the second soldering tooth, a cross-sectional area of at least a part of the second soldering tooth is the same.

13. The ultrasonic welding head according to claim 1, wherein The cross-section of the second soldering tooth is arcuate, circular or elliptical.

14. The ultrasonic welding head according to any one of claims 1-13, characterized in that, The second soldering tooth includes one tooth portion; or the second soldering tooth includes multiple tooth portions, a surface of the tooth portion away from the soldering surface constitutes a tooth portion end surface, the multiple tooth portions are respectively a first tooth portion to an m-th tooth portion sequentially arranged along a protruding direction of the second soldering tooth, an n-th tooth portion is arranged on the tooth portion end surface of the (n - 1)-th tooth portion, and a projection of the n-th tooth portion on the tooth portion end surface of the (n - 1)-th tooth portion is located within the tooth portion end surface of the (n - 1)-th tooth portion, where 2 ≤ n ≤ m.

15. The ultrasonic welding head according to any one of claims 1-13, characterized in that, The first soldering tooth structure includes a first soldering tooth, a surface of the first soldering tooth away from the soldering surface constitutes a soldering tooth end surface, the second soldering tooth is arranged on the soldering tooth end surface, and a projection of the second soldering tooth on the soldering tooth end surface is located within the soldering tooth end surface.

16. The ultrasonic welding head according to claim 15, characterized in that, In a protruding direction of the first soldering tooth relative to the soldering surface, a tooth height of the first soldering tooth is h1, and a tooth height of the second soldering tooth is h2, and a ratio range of h2 to h1 is 0.3 to 0.

8.

17. The ultrasonic welding head according to claim 15, characterized in that, In a protruding direction of the first soldering tooth relative to the soldering surface, a tooth height of the first soldering tooth is h1, and a value range of h1 is 0.2 mm to 0.6 mm.

18. The ultrasonic welding head according to claim 15, characterized in that, The soldering tooth end surface is a plane.

19. The ultrasonic welding head according to claim 15, characterized in that, The first welding tooth structure includes a third welding tooth, and the third welding tooth is disposed between adjacent first welding teeth; and / or, the first welding tooth structure includes a fourth welding tooth, and the fourth welding tooth is disposed between the first welding tooth and the edge of the welding surface.

20. The ultrasonic welding head according to claim 15, characterized in that, The first welding tooth includes a welding tooth main body and a plurality of welding tooth branches. The welding tooth main body extends in a long strip shape in the extending direction of the welding surface. The plurality of welding tooth branches are connected to at least one side in the width direction of the welding tooth main body. The second welding tooth is disposed on the welding tooth main body and is consistent with the extending direction of the welding tooth main body.

21. The ultrasonic welding head according to claim 20, wherein, The width of the second welding tooth is W2, the width of the welding tooth main body is W1, and W2 ≤ W1.

22. The ultrasonic welding head according to claim 20, wherein, The ratio range of W2 to W1 is 0.5 to 0.

9.

23. The ultrasonic welding head according to claim 20, wherein, The first welding tooth structure includes a third welding tooth. A plurality of accommodating grooves are defined between adjacent first welding teeth. The plurality of accommodating grooves are arranged at intervals along the extending direction of the welding tooth main body. The welding tooth branches are located between adjacent two of the accommodating grooves, and the third welding tooth is located in the accommodating groove.

24. The ultrasonic welding head according to claim 23, wherein The third welding tooth is in the shape of a frustum of a pyramid.

25. The ultrasonic welding head according to claim 20, wherein, The first welding tooth structure includes a fourth welding tooth. The fourth welding tooth is disposed between the first welding tooth and the edge of the welding surface. The fourth welding tooth is plural, and the plurality of fourth welding teeth on the same side of the first welding tooth are arranged at intervals along the extending direction of the welding tooth main body.

26. An ultrasonic welding device, characterized in that, Comprising: The ultrasonic welding head according to any one of claims 1-25.

27. A method for detecting wear of an ultrasonic welding head, characterized in that, The ultrasonic welding head is the ultrasonic welding head according to any one of claims 1-25. The method for detecting the wear of the ultrasonic welding head includes: Performing ultrasonic pre-welding on a workpiece sample by using the ultrasonic welding head. The weld mark corresponding to the second welding tooth on the workpiece sample is a second weld mark; Identifying the second weld mark formed on the workpiece sample; Calculating the weld mark area of a single second weld mark; Judging the wear condition of the ultrasonic welding head according to the weld mark area of a single second weld mark.

28. The method for detecting wear of an ultrasonic welding head according to claim 27, wherein, Identifying the second weld mark formed on the workpiece sample includes: Collecting a weld mark image of the side of the workpiece sample where the weld mark is formed; Identifying the second weld mark in the weld mark image.

29. The method for detecting wear of an ultrasonic welding head according to claim 27, wherein, Calculating the weld mark area of a single second weld mark includes: Identifying the outer contour of a single second weld mark; Calculating the area of the figure enclosed by the outer contour of the second weld mark.

30. The method for detecting wear of an ultrasonic welding head according to claim 27, characterized in that, Judging the wear condition of the ultrasonic welding head according to the weld mark area of a single second weld mark includes: Judging the wear condition of the ultrasonic welding head according to the ratio of the weld mark area of a single second weld mark to the designed area of a single second weld mark.

31. The ultrasonic welding head wear detection method according to claim 30, characterized in that, Judging the wear condition of the ultrasonic welding head according to the ratio of the weld mark area of a single second weld mark to the designed area of a single second weld mark includes: The weld mark area of a single second weld mark is Sx, the designed area of a single second weld mark is S0. When the ratio of Sx to S0 is less than 0.2, it is judged that the service life of the ultrasonic welding head has reached.

32. A battery cell, characterized in that, Comprising: A housing, and the housing is provided with electrode terminals; An electrode assembly, the electrode assembly is disposed in the housing and includes a tab, the tab is connected to the electrode terminal, the tab includes a plurality of tab pieces stacked and welded together, a welding mark area is formed on the tab, the welding mark area is formed by welding with an ultrasonic welding head according to any one of claims 1-25, the welding mark area includes a first welding mark and a second welding mark, both the first welding mark and the second welding mark are formed as groove structures, and the second welding mark is formed on the bottom wall of the first welding mark and extends in a long strip shape.

33. The battery cell according to claim 32, wherein, The first welding mark includes a welding mark main body and a plurality of welding mark branches, the welding mark main body is in a long strip shape, and the plurality of welding mark branches are connected to at least one side in the width direction of the welding mark main body, and the second welding mark is formed on the bottom wall of the welding mark main body and is consistent with the extending direction of the welding mark main body.

34. The battery cell according to claim 32, wherein, The welding mark area includes a third welding mark, and the third welding mark is located between adjacent first welding marks; and / or, the welding mark area includes a fourth welding mark, and the fourth welding mark is located between the first welding mark and the edge of the tab.

35. The battery cell according to any one of claims 32 - 34, characterized in that, The plurality of tab pieces of the tab are ultrasonically welded and connected, the tab is laser welded and connected to the electrode terminal to form a laser welding seam, and the laser welding seam is disposed opposite to the second welding mark in the stacking direction of the plurality of tab pieces.

36. A battery device, characterized in that, Comprising: A box body; A battery cell according to any one of claims 32-35, the battery cell is disposed in the box body.

37. An electrical device, characterized in that, Including the battery device according to claim 36.

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