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. The ultrasonic welding head comprises a welding head body, main welding teeth and auxiliary welding teeth. The welding head body is provided with a welding face, the main welding teeth are arranged on the welding face in a protruding mode at intervals, in the protruding direction of the welding teeth relative to the welding face, the tooth height of the main welding teeth is h1, the auxiliary welding teeth are arranged on the welding face in a protruding mode and located between the adjacent main welding teeth, in the protruding direction of the welding teeth relative to the welding face, the tooth height of the auxiliary welding teeth is h2, and the ratio of h2 to h1 ranges from 0.2 to 0.8. According to the ultrasonic welding head, when the ultrasonic welding head is used for welding workpieces of multiple layers of foils such as multiple layers of electrode lug pieces and switching pieces, the problems of insufficient welding and insufficient electrode lug overcurrent area caused by insufficient welding can be solved, the welding quality of the multiple layers of electrode lug pieces and the switching pieces can be improved, and the service stability of a battery can be 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, the tab is an important part of the battery cell and plays an important role in current flow. Usually, an adapter is used to connect the tab to the electrode terminal of the battery cell, thereby realizing the electrical connection between the tab and the electrode terminal. Ultrasonic welding is usually used in the battery to realize the welding connection between the multi-layer tab sheet and the adapter.

[0003] However, during the ultrasonic welding of the multi-layer tabs and adapters, poor welding problems such as cold welding are prone to occur. Cold welding will weaken the tab's current capacity, greatly reducing the battery's charge and discharge capacity. In serious cases, excessive heat may be generated in the welding area between the tabs and adapters, causing local ablation of the battery tabs, thereby affecting the battery's service reliability. Therefore, how to improve the welding quality of the multi-layer tabs and adapters and improve the battery's service stability is a technical problem that needs to be solved urgently. Summary of the invention

[0004] In view of the above problems, 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 multi-layer foil workpieces such as multi-layer pole tabs and adapters, the problem of cold welding and the problem of insufficient pole tab flow area caused by cold welding can be reduced, the welding quality of the multi-layer pole tabs and adapters can be improved, and the service stability of the battery can be improved.

[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; main welding teeth, the main welding teeth are protruding from the welding surface and are arranged in a plurality of intervals, and the tooth height of the main welding teeth in the protruding direction of the welding teeth relative to the welding surface is h1; auxiliary welding teeth, the auxiliary welding teeth are protruding from the welding surface and are located between adjacent main welding teeth, and the tooth height of the auxiliary welding teeth in the protruding direction of the welding teeth relative to the welding surface is h2; wherein the ratio range of h2 to h1 is 0.2 to 0.8.

[0006] In the above technical solution, by providing a plurality of main welding teeth arranged at intervals on the welding surface, when using this ultrasonic welding head to weld workpieces such as multi-layer tab pieces and adapter pieces, the main welding teeth can play a major role in welding connection. By adding auxiliary welding teeth between the main welding teeth and the tooth height of the auxiliary welding teeth being less than or equal to that of the main welding teeth, the auxiliary welding teeth can perform local strengthening welding on the un-welded areas between the layers of the multi-layer foil, reducing the problem of local virtual welding of the tab and the problem of insufficient current-carrying area of the tab caused by the local virtual welding problem of the tab, improving the welding quality of the multi-layer tab piece and the adapter piece, and since the welding area of the tab and the adapter piece is increased, the risk of local ablation of the battery electrode caused by over-concentrated heat generation in the welding area of the tab and the adapter piece during the operation of the battery can be reduced, which is beneficial to improving the service stability of the battery.

[0007] In the above technical solution, by making the ratio of the tooth height h2 of the auxiliary welding teeth to the tooth height h1 of the main welding teeth not less than 0.2, the auxiliary welding teeth can perform effective local strengthening welding on the un-welded areas between the layers of the multi-layer foil, enhancing the local strengthening welding effect; by making the ratio of the tooth height h2 of the auxiliary welding teeth to the tooth height h1 of the main welding teeth not greater than 0.8, the influence of the auxiliary welding teeth on the main welding teeth can be reduced. While the main welding teeth play a major welding role, the auxiliary welding teeth cooperate with the main welding teeth to perform effective local strengthening welding on the un-welded areas between the main welding teeth, which can better reduce the virtual welding problem and better improve the welding quality of the multi-layer foil.

[0008] In some embodiments, the projection of a single main welding tooth on the welding surface is a first projection, and the projection of a single auxiliary welding tooth on the welding surface is a second projection, and the ratio of the area of the second projection to the area of the first projection is less than 1.

[0009] In the above technical solution, by making the ratio of the area of the projection of a single auxiliary welding tooth on the welding surface to the area of the projection of a single main welding tooth on the welding surface less than 1, the contact area between the main welding teeth and the multi-layer foil is greater than the contact area between the auxiliary welding teeth and the multi-layer foil, which can make the main welding teeth play a major welding role better relative to the auxiliary welding teeth. The auxiliary welding teeth cooperate with the main welding teeth to perform effective local strengthening welding on the un-welded areas between the main welding teeth, which can make the cooperation effect between the auxiliary welding teeth and the main welding teeth better, better reduce the virtual welding problem, and better improve the welding quality of the multi-layer foil.

[0010] In some embodiments, the ratio of the area of the second projection to the area of the first projection is 0.1 - 0.8.

[0011] In the above technical solution, by making the ratio of the area of the projection of a single auxiliary welding tooth on the welding surface to the area of the projection of a single main welding tooth on the welding surface not less than 0.1, the auxiliary welding tooth can effectively perform local strengthening welding on the interlayer unwelded area of the multi-layer foil. The local strengthening area is relatively large, which helps to improve the local strengthening welding effect. By making the ratio of the area of the projection of a single auxiliary welding tooth on the welding surface to the area of the projection of a single main welding tooth on the welding surface not greater than 0.8, the influence of the auxiliary welding tooth on the main welding tooth can be reduced. While the main welding tooth plays a major welding role, the auxiliary welding tooth cooperates with the main welding tooth to effectively perform local strengthening welding on the unwelded area between the main welding teeth, which can better reduce the problem of false soldering and better improve the welding quality of the multi-layer foil.

[0012] In some embodiments, the projection of a single auxiliary welding tooth on the welding surface is a second projection, and the surface of the main welding tooth away from the welding surface forms a tooth end surface. The projection of a single tooth end surface on the welding surface is a third projection, and the ratio of the area of the second projection to the area of the third projection is less than 1.

[0013] In the above technical solution, by making the ratio of the area of the projection of a single auxiliary welding tooth on the welding surface to the area of the projection of the tooth end surface of a single main welding tooth on the welding surface less than 1, and the contact area between the main welding tooth and the multi-layer foil is greater than the contact area between the auxiliary welding tooth and the multi-layer foil, the main welding tooth can play a major welding role better than the auxiliary welding tooth. The auxiliary welding tooth cooperates with the main welding tooth to effectively perform local strengthening welding on the unwelded area between the main welding teeth, which can make the cooperation effect between the auxiliary welding tooth and the main welding tooth better, can better reduce the problem of false soldering, and better improve the welding quality of the multi-layer foil.

[0014] In some embodiments, the ratio of the area of the second projection to the area of the third projection is 0.3 to 0.8.

[0015] In the above technical solution, by making the ratio of the area of the projection of a single auxiliary welding tooth on the welding surface to the area of the projection of the tooth end surface of a single main welding tooth on the welding surface not less than 0.3, the auxiliary welding tooth can effectively perform local strengthening welding on the interlayer unwelded area of the multi-layer foil. The local strengthening area is relatively large, which helps to improve the local strengthening welding effect. By making the ratio of the area of the projection of a single auxiliary welding tooth on the welding surface to the area of the projection of the tooth end surface of a single main welding tooth on the welding surface not greater than 0.8, the influence of the auxiliary welding tooth on the main welding tooth can be reduced. While the main welding tooth plays a major welding role, the auxiliary welding tooth cooperates with the main welding tooth to effectively perform local strengthening welding on the unwelded area between the main welding teeth, which can better reduce the problem of false soldering and better improve the welding quality of the multi-layer foil.

[0016] In some embodiments, the projection of a single main welding tooth on the welding surface is a first projection, and the projection of a single auxiliary welding tooth on the welding surface is a second projection, and the second projection is spaced from the first projection.

[0017] In the above technical solution, by arranging the projection of a single auxiliary welding tooth on the welding surface to be spaced from the projection of a single main welding tooth on the welding surface, a gap can be formed between the auxiliary welding tooth and the main welding tooth. In this way, when using this ultrasonic welding head to weld workpieces such as multi-layer tab pieces and adapter pieces (multi-layer foil materials), the gap between the auxiliary welding tooth and the main welding tooth can reserve an overflow space for the overflow material during the welding process, reducing the problem of large local stress caused by overly concentrated overflow material and resulting in welding cracks, which is beneficial to further improving the welding quality.

[0018] In some embodiments, the minimum distance between the second projection and the first projection is d, the equivalent diameter of the second projection is D0, and the ratio of d to D0 is less than 0.35.

[0019] In the above technical solution, by making the distance d between the projection of a single auxiliary welding tooth on the welding surface and the projection of a single main welding tooth on the welding surface and the equivalent diameter D0 of the projection of a single main welding tooth on the welding surface satisfy: the ratio of d to D0 is less than 0.35, the distance between the projection of a single auxiliary welding tooth on the welding surface and the projection of a single main welding tooth on the welding surface can be made smaller. While reserving an overflow space for the overflow material during the welding process, it can enable the auxiliary welding tooth to locally strengthen a larger area of the un-welded area between the main welding teeth, further reducing the area of the un-welded area between the multi-layer foils, thereby further reducing the position or area of the virtual welding, better reducing the virtual welding problem, and better improving the welding quality of the multi-layer foils.

[0020] In some embodiments, the ratio range of d to D0 is 0.1 - 0.25.

[0021] In the above technical solution, by making the ratio of the distance d between the projection of a single auxiliary welding tooth on the welding surface and the projection of a single main welding tooth on the welding surface to the equivalent diameter D0 of the projection of a single main welding tooth on the welding surface not less than 0.1, a relatively sufficient overflow space can be reserved for the overflow material during the welding process to better reduce the problem of large local stress caused by overly concentrated overflow material and resulting in welding cracks; and, by making the ratio of the distance d between the projection of a single auxiliary welding tooth on the welding surface and the projection of a single main welding tooth on the welding surface to the equivalent diameter D0 of the projection of a single main welding tooth on the welding surface not greater than 0.25, the auxiliary welding tooth can locally strengthen a larger area of the un-welded area between the main welding teeth, further reducing the area of the un-welded area between the multi-layer foils, thereby further reducing the position or area of the virtual welding, better reducing the virtual welding problem, and better improving the welding quality of the multi-layer foils.

[0022] In some embodiments, multiple main welding teeth are arranged in multiple rows and columns. The multiple columns of main welding teeth are arranged along a first direction, and the multiple rows of main welding teeth are arranged along a second direction. The first direction intersects the second direction. A first channel is formed between adjacent two columns of main welding teeth, and a second channel is formed between adjacent two rows of main welding teeth. The first channel intersects the second channel. The first channel and / or the second channel is provided with auxiliary welding teeth.

[0023] In the above technical solution, by arranging multiple main welding teeth in multiple rows and columns, the welding connections of main welding teeth can be obtained at different positions of multiple layers of foils, reducing the area of the un-welded area between layers of multiple layers of foils, which is beneficial to reducing the problem of false soldering. Moreover, by arranging the auxiliary welding teeth between adjacent two columns or adjacent two rows of main welding teeth, the auxiliary welding teeth can perform local strengthening welding on the un-welded area between adjacent two columns or adjacent two rows of main welding teeth, reducing the problem of false soldering and improving the welding quality of multiple layers of foils.

[0024] In some embodiments, the projection of a single auxiliary welding tooth on the welding surface is a second projection, the projection of a single first channel on the welding surface is a fourth projection, and the projection of a single second channel on the welding surface is a fifth projection. The maximum dimension of the second projection in the first direction is D1, the maximum dimension of the second projection in the second direction is D2, the width dimension of the fourth projection in the first direction is W1, and the width dimension of the fifth projection in the second direction is W2. Wherein, the ratio of D1 to W1 is greater than 0.8 and / or the ratio of D2 to W2 is greater than 0.8.

[0025] In the above technical solution, by making the ratio of the dimension of the projection of the auxiliary welding tooth on the welding surface in the arrangement direction of multiple main welding teeth to the width dimension of the first channel or the second channel formed between multiple main welding teeth in the arrangement direction of multiple main welding teeth greater than 0.8, the size of the auxiliary welding tooth can be made larger, so that the auxiliary welding tooth can perform local strengthening welding on a larger area of the un-welded area between adjacent two columns or adjacent two rows of main welding teeth, better reducing the problem of false soldering and further improving the welding quality of multiple layers of foils.

[0026] In some embodiments, the auxiliary welding teeth are arranged at the intersection of the first channel and the second channel.

[0027] In the above technical solution, during the welding process of multi-layer foils using the ultrasonic welding head, the overflow of materials is relatively serious and the material arch is relatively high at the intersection of the first channel and the second channel in the multi-layer foils. Therefore, the risk of false soldering is relatively high. By providing auxiliary welding teeth at the intersection of the first channel and the second channel formed between multiple main welding teeth, the auxiliary welding teeth can compact the position where the overflow of materials is relatively serious and the material arch is relatively high. By locally strengthening the welding of the area with a relatively high risk of false soldering through the auxiliary welding teeth, the problem of false soldering can be better reduced, and further the welding quality of the multi-layer foils can be improved.

[0028] In some embodiments, the projection of a single auxiliary welding tooth on the welding surface is the second projection, the projection of a single first channel on the welding surface is the fourth projection, and the projection of a single second channel on the welding surface is the fifth projection. The maximum dimension of the second projection in the first direction is D1, the maximum dimension of the second projection in the second direction is D2, the width dimension of the fourth projection in the first direction is W1, and the width dimension of the fifth projection in the second direction is W2. The ratio of W1 to W2 is greater than 1; wherein, the auxiliary welding tooth provided at the intersection of the first channel and the second channel satisfies: the ratio of D2 to W2 is greater than 1.

[0029] In the above technical solution, by making the width ratio of the first channel and the second channel formed between multiple main welding teeth greater than 1, and making the auxiliary welding tooth provided at the intersection of the first channel and the second channel satisfy: the ratio of the maximum D2 of the projection of the auxiliary welding tooth on the welding surface in the second direction to the width W2 of the second channel in the second direction is greater than 1, the relatively large width space of the first channel can be fully utilized, so that the size of the auxiliary welding tooth can be set larger, so that the auxiliary welding tooth can perform local strengthening welding on a relatively large area of the un-welded area between multiple main welding teeth, better reduce the problem of false soldering, and further improve the welding quality of the multi-layer foils.

[0030] In some embodiments, the auxiliary welding tooth provided at the intersection of the first channel and the second channel satisfies: the ratio range of D2 to W2 is 1.5 to 3.

[0031] In the above technical solution, by making the auxiliary welding teeth provided at the intersection of the first channel and the second channel satisfy that the ratio of the maximum D2 in the second direction of the projection of the auxiliary welding teeth on the welding surface to the width W2 in the second direction of the second channel is not less than 1.5, the relatively large width space of the first channel can be fully utilized, so that the size of the auxiliary welding teeth can be set larger. Thus, the auxiliary welding teeth can perform local strengthening welding on a relatively large area of the interlayer unwelded area between multiple main welding teeth, better reducing the problem of false soldering and further improving the welding quality of the multi-layer foil. By making the auxiliary welding teeth provided at the intersection of the first channel and the second channel satisfy that the ratio of the maximum D2 in the second direction of the projection of the auxiliary welding teeth on the welding surface to the width W2 in the second direction of the second channel is not greater than 3, while fully utilizing the relatively large width space of the first channel and making the size of the auxiliary welding teeth larger, the adhesion problem caused by the too large contact area between the ultrasonic welding head and the workpiece due to the too large size of the auxiliary welding teeth can be reduced. Therefore, while taking into account that the auxiliary welding teeth perform local strengthening welding on a relatively large area of the interlayer unwelded area between multiple main welding teeth, better reducing the problem of false soldering and further improving the welding quality of the multi-layer foil, the adhesion problem between the ultrasonic welding head and the workpiece can be reduced.

[0032] In some embodiments, the auxiliary welding teeth provided at the intersection of the first channel and the second channel satisfy that the ratio of D1 to W1 is less than 1.

[0033] In the above technical solution, by making the auxiliary welding teeth provided at the intersection of the first channel and the second channel satisfy that the ratio of the maximum D1 in the first direction of the projection of the auxiliary welding teeth on the welding surface to the width W1 in the first direction of the first channel is less than 1, while fully utilizing the relatively large width space of the first channel and making the size of the auxiliary welding teeth larger, a gap can be left between the auxiliary welding teeth and the main welding teeth in the first direction to provide an overflow space for the overflow material generated during the welding process. In this way, it is possible to take into account that the auxiliary welding teeth perform local strengthening welding on a relatively large area of the interlayer unwelded area between multiple main welding teeth, better reducing the problem of false soldering and further improving the welding quality of the multi-layer foil, and the problem of welding cracks caused by too large local stress due to too concentrated overflow material can be reduced, further improving the welding quality.

[0034] In some embodiments, the number of columns of the main welding teeth is greater than the number of rows of the main welding teeth.

[0035] In the above technical solution, by making the number of columns of the main welding teeth greater than the number of rows of the main welding teeth, a relatively large number of first channels can be formed between multiple main welding teeth. Since the number of first channels with a relatively large width is relatively large, more layout space can be provided for more auxiliary welding teeth and the size of the auxiliary welding teeth can be made relatively large, which is more conducive to the auxiliary welding teeth cooperating with the main welding teeth to effectively perform local strengthening welding on the unwelded area between the main welding teeth, better reducing the problem of virtual welding and better improving the welding quality of multi-layer foils.

[0036] In some embodiments, there are multiple auxiliary welding teeth. The multiple auxiliary welding teeth include a first auxiliary welding tooth disposed at the intersection of the first channel and the second channel. The multiple auxiliary welding teeth further include at least one of a second auxiliary welding tooth and a third auxiliary welding tooth. The second auxiliary welding tooth is disposed in the first channel and is offset from the intersection position of the first channel and the second channel. The third auxiliary welding tooth is disposed in the second channel and is offset from the intersection position of the first channel and the second channel. Wherein, in the protruding direction of the welding teeth relative to the welding surface, the tooth height of the second auxiliary welding tooth and the third auxiliary welding tooth is less than the tooth height of the first auxiliary welding tooth.

[0037] In the above technical solution, by setting the auxiliary welding teeth to be multiple, local strengthening welding can be performed on the interlayer unwelded areas at multiple different positions, better reducing the problem of virtual welding. Moreover, the multiple auxiliary welding teeth include a first auxiliary welding tooth disposed at the intersection of the first channel and the second channel. The first auxiliary welding tooth can compact the position where the overflow of materials is relatively serious and the material arching is relatively high. By performing local strengthening welding on the area with a relatively high risk of virtual welding through the auxiliary welding teeth, the problem of virtual welding can be better reduced, further improving the welding quality of multi-layer foils. Additionally, the multiple auxiliary welding teeth further include at least one of a second auxiliary welding tooth and a third auxiliary welding tooth. The second auxiliary welding tooth is disposed in the first channel and is offset from the intersection position of the first channel and the second channel. The second auxiliary welding tooth can perform local strengthening welding on the interlayer unwelded area between two adjacent columns of main welding teeth. The third auxiliary welding tooth is disposed in the second channel and is offset from the intersection position of the first channel and the second channel. The third auxiliary welding tooth can perform local strengthening welding on the interlayer unwelded area between two adjacent rows of main welding teeth.

[0038] In addition, at the intersection position of the multi-layer foil corresponding to the first channel and the second channel, compared with other positions of the first channel and the second channel, the overflow of materials is more serious and the arching height is higher. The tooth height of the first auxiliary welding tooth is relatively high, while the tooth heights of the second auxiliary welding tooth and the third auxiliary welding tooth are relatively small. This can better match the specific conditions of the corresponding positions of the multi-layer foil, achieve local strengthening welding of the multiple interlayer unwelded areas between multiple main welding teeth, better reduce the problem of false soldering, further improve the welding quality of the multi-layer foil, and can reduce the problem of large local stress caused by overly concentrated overflow of materials, which may lead to welding crack problems, and further improve the welding quality.

[0039] In some embodiments, there are multiple auxiliary welding teeth. The multiple auxiliary welding teeth include a first auxiliary welding tooth disposed at the intersection of the first channel and the second channel. The multiple auxiliary welding teeth further include at least one of a second auxiliary welding tooth and a third auxiliary welding tooth. The second auxiliary welding tooth is disposed in the first channel and is offset from the intersection position of the first channel and the second channel. The third auxiliary welding tooth is disposed in the second channel and is offset from the intersection position of the first channel and the second channel. Among them, the projected area of a single second auxiliary welding tooth and a single third auxiliary welding tooth on the welding surface is smaller than the projected area of a single first auxiliary welding tooth on the welding surface.

[0040] In the above technical solution, by setting the auxiliary welding teeth to be multiple, local strengthening welding can be performed on the interlayer unwelded areas at multiple different positions, which can better reduce the problem of false soldering. Moreover, the multiple auxiliary welding teeth include a first auxiliary welding tooth disposed at the intersection of the first channel and the second channel. The first auxiliary welding tooth can compact the position where the overflow of materials is more serious and the material arching is higher. By performing local strengthening welding on the area with a relatively high risk of false soldering through the auxiliary welding teeth, the problem of false soldering can be better reduced, and the welding quality of the multi-layer foil can be further improved. Additionally, the multiple auxiliary welding teeth further include at least one of a second auxiliary welding tooth and a third auxiliary welding tooth. The second auxiliary welding tooth is disposed in the first channel and is offset from the intersection position of the first channel and the second channel. The second auxiliary welding tooth can perform local strengthening welding on the interlayer unwelded area between two adjacent columns of main welding teeth. The third auxiliary welding tooth is disposed in the second channel and is offset from the intersection position of the first channel and the second channel. The third auxiliary welding tooth can perform local strengthening welding on the interlayer unwelded area between two adjacent rows of main welding teeth.

[0041] In addition, at the intersection position of the multi-layer foil corresponding to the first channel and the second channel, compared with other positions of the first channel and the second channel, the overflow of materials is more serious and the arch height is higher. The projected area of the first auxiliary welding tooth on the welding surface is larger, while the projected areas of the second auxiliary welding tooth and the third auxiliary welding tooth on the welding surface are smaller, which can better match the specific conditions of the corresponding positions of the multi-layer foil. It can achieve local strengthening welding of the multiple interlayer unwelded areas between multiple main welding teeth, better reduce the problem of false soldering, further improve the welding quality of the multi-layer foil, and can reduce the problem of large local stress caused by too concentrated overflow of materials, resulting in welding crack problems, and further improve the welding quality. Moreover, it can also reduce the adhesion problem caused by the too large contact area between the ultrasonic welding head and the workpiece. Therefore, while taking into account that the auxiliary welding teeth perform large-area local strengthening welding on the interlayer unwelded areas between multiple main welding teeth, better reducing the problem of false soldering and further improving the welding quality of the multi-layer foil, the adhesion problem between the ultrasonic welding head and the workpiece can be reduced.

[0042] In some embodiments, in the protruding direction of the welding tooth relative to the welding surface, the cross-sectional area of the main welding tooth gradually decreases.

[0043] In the above technical solution, by making the cross-sectional area of the main welding tooth gradually decrease in the protruding direction of the welding tooth relative to the welding surface, under a certain welding pressure, the pressure of the main welding tooth on the multi-layer foil can be made larger, which is beneficial to enhancing the welding connection strength between the multi-layer foils and improving the firmness of the welding connection between the multi-layer foils.

[0044] In some embodiments, in the protruding direction of the welding tooth relative to the welding surface, the cross-sectional area of the auxiliary welding tooth gradually decreases.

[0045] In the above technical solution, by making the cross-sectional area of the auxiliary welding tooth gradually decrease in the protruding direction of the welding tooth relative to the welding surface, under a certain welding pressure, the pressure of the auxiliary welding tooth on the multi-layer foil can be made larger, which can better achieve local strengthening welding of the interlayer unwelded areas between the main welding teeth, reduce the problem of false soldering, and improve the welding quality of the multi-layer foil.

[0046] In some embodiments, the main welding tooth is frustum-shaped or spherical.

[0047] In the above technical solution, by setting the main welding tooth to be frustum-shaped or spherical, the structure of the main welding tooth can be made simple and convenient for processing and manufacturing; moreover, under a certain welding pressure, the main welding tooth of this structural form can have a larger pressure on the multi-layer foil, which is beneficial to enhancing the welding connection strength between the multi-layer foils and improving the firmness of the welding connection between the multi-layer foils.

[0048] In some embodiments, the auxiliary welding tooth is spherical.

[0049] In the above technical solution, by setting the auxiliary welding teeth as spherical, the structure of the auxiliary welding teeth can be simple, which is convenient for processing and manufacturing; moreover, the shape of the overflow area between the spherical auxiliary welding teeth and the adjacent main welding teeth is relatively matched, and the overflow area between the adjacent main welding teeth can be better compacted, which can improve the overflow problem and the cracking problem caused by the overflow problem. And the overflow area also belongs to the interlayer non-welded area, and the local strengthening welding of the overflow area can also be better carried out.

[0050] In some embodiments, an avoidance surface is formed on the welding head body. The avoidance surface is located on the outer peripheral side of the welding surface and is connected to the welding surface. The included angle between the avoidance surface and the welding surface is an obtuse angle, and the avoidance surface and the welding surface are smoothly transitioned through an arc surface. A shaping welding tooth is provided at the connection between the avoidance surface and the welding surface.

[0051] In the above technical solution, by providing an inclined avoidance surface at the position on the outer peripheral side of the welding surface of the welding head body, and the included angle between the avoidance surface and the welding surface is an obtuse angle, the avoidance surface can be used to avoid the warping of the edge area of the multi-layer foil caused by the local pressurization of the multi-layer foil by the welding head body during the welding process, and the acting force between the welding head body and the upper edge area of the multi-layer foil can be reduced, so that the welding head body is not easy to cut the multi-layer foil during the welding process, and the welding cracking problem of the multi-layer foil can be effectively improved; moreover, a shaping welding tooth is provided at the connection between the avoidance surface and the welding surface, and the shaping welding tooth has a pre-pressing and shaping effect on the multi-layer foil, which is convenient for the main welding teeth and the auxiliary welding teeth on the welding surface to contact the surface of the multi-layer foil.

[0052] In a second aspect, the present invention provides an ultrasonic welding device, including: the ultrasonic welding head of the first aspect embodiment of the present invention above.

[0053] In the above technical solution, by providing the above ultrasonic welding head, the ultrasonic welding head is provided with a plurality of main welding teeth arranged at intervals on the welding surface. When using the ultrasonic welding head to weld workpieces such as multi-layer tab pieces and transfer pieces, the main welding teeth can play a main welding connection role. By adding auxiliary welding teeth between the main welding teeth and the tooth height of the auxiliary welding teeth is less than or equal to that of the main welding teeth, the auxiliary welding teeth can perform local strengthening welding on the interlayer non-welded area of the multi-layer foil, which can reduce the problem of local virtual welding of the tab and the problem of insufficient overcurrent area of the tab caused by the local virtual welding of the tab, improve the welding quality of the multi-layer tab piece and the transfer piece, and since the welding area of the tab and the transfer piece is increased, the risk of local ablation of the battery electrode caused by excessive heat generation in the welding area of the tab and the transfer piece during the operation of the battery can be reduced, which is beneficial to improving the service stability of the battery.

[0054] In a third aspect, the present invention provides a method for detecting wear of an ultrasonic welding head, where the ultrasonic welding head is the ultrasonic welding head of the first aspect embodiment of the present invention. The method for detecting wear of the ultrasonic welding head includes: performing ultrasonic pre-welding on a workpiece sample using the ultrasonic welding head. The welding mark corresponding to the main welding teeth on the workpiece sample is the first welding mark, and the welding mark corresponding to the auxiliary welding teeth on the workpiece sample is the second welding mark; identifying the first welding mark and / or the second welding mark formed on the workpiece sample; calculating the welding mark area of a single first welding mark and / or calculating the welding mark area of a single second welding mark; and determining the wear condition of the ultrasonic welding head based on the welding mark area of a single first welding mark and / or the welding mark area of a single second welding mark.

[0055] In the above technical solution, by calculating the welding mark area of a single first welding mark corresponding to the main welding teeth formed on the workpiece sample and / or calculating the welding mark area of a single second welding mark corresponding to the auxiliary welding teeth formed on the workpiece sample, the wear condition of the main welding teeth and / or the auxiliary welding teeth in the ultrasonic welding head can be judged more intuitively and accurately. Thus, the ultrasonic welding head can be replaced in time or repaired, reducing problems such as poor welding of multi-layer foils caused by wear of the ultrasonic welding head, such as false welding. Therefore, effective monitoring of false welding can be achieved, which helps to improve the welding quality of the ultrasonic welding head for multi-layer foils, and thus can improve the quality reliability and stability of ultrasonic welding marks, and further improve the service reliability of the battery.

[0056] In some embodiments, identifying the first welding mark and / or the second welding mark formed on the workpiece sample includes: collecting a welding mark image on the side of the workpiece sample where the welding mark is formed; and identifying the first welding mark and / or the second welding mark in the welding mark image.

[0057] In the above technical solution, by collecting the welding mark image on the side of the workpiece sample where the welding mark is formed and identifying the first welding mark and / or the second welding mark in the welding mark image, the first welding mark and / or the second welding mark can be conveniently identified and found.

[0058] In some embodiments, calculating the welding mark area of a single first welding mark includes: identifying the outer contour of a single first welding mark; and calculating the area of the figure enclosed by the outer contour of the first welding mark.

[0059] In the above technical solution, by first identifying the outer contour of a single first welding mark and then calculating the area of the figure enclosed by the outer contour of the first welding mark, the welding mark area of the first welding mark can be conveniently calculated. This calculation method of the welding mark area is simple and the calculation result is relatively accurate.

[0060] In some embodiments, 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.

[0061] In the above technical solution, by first identifying the outer contour of a single second weld mark and then calculating the area of the figure enclosed by the outer contour of the second weld mark, the weld mark area of the second weld mark can be conveniently calculated. The calculation method of the weld mark area is simple and the calculation result is relatively accurate.

[0062] In some embodiments, determining the wear condition of the ultrasonic welding head according to the weld mark area of a single first weld mark includes: determining the wear condition of the ultrasonic welding head according to the ratio of the weld mark area of a single first weld mark to the designed area of a single first weld mark.

[0063] In the above technical solution, by the size relationship of the ratio of the weld mark area of a single first weld mark to the designed area of a single first weld mark, the reduced amount of the weld mark area of the current first weld mark relative to the designed area of the first weld mark can be obtained. The reduced amount of the weld mark area of the first weld mark relative to the designed area of the first weld mark can more intuitively reflect the wear condition of the main welding teeth, and thus can reflect the wear condition of the ultrasonic welding head, which helps to improve the accuracy of determining the wear condition of the ultrasonic welding head.

[0064] In some embodiments, determining the wear condition of the ultrasonic welding head according to the weld mark area of a single second weld mark includes: determining 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.

[0065] In the above technical solution, by the size relationship of the ratio of the weld mark area of a single second weld mark to the designed area of a single second weld mark, the reduced amount of the weld mark area of the current second weld mark relative to the designed area of the second weld mark can be obtained. The reduced amount of the weld mark area of the second weld mark relative to the designed area of the second weld mark can more intuitively reflect the wear condition of the auxiliary welding teeth, and thus can reflect the wear condition of the ultrasonic welding head, which helps to improve the accuracy of determining the wear condition of the ultrasonic welding head.

[0066] In some embodiments, determining the wear condition of the ultrasonic welding head according to the ratio of the weld mark area of a single first weld mark to the designed area of a single first weld mark includes: the weld mark area of a single first weld mark is Sx, the designed area of a single first weld mark is S1, and when the ratio of Sx to S1 is less than 0.2, it is determined that the life of the ultrasonic welding head has reached.

[0067] In the above technical solution, by determining whether the ratio of the weld area Sx of a single first weld mark to the designed area S1 of the single first weld mark is less than 0.2, the wear degree of the main welding teeth can be judged, so that it can be judged whether the life of the ultrasonic welding head has reached, and it is possible to simply and accurately judge whether the ultrasonic welding head should be replaced or repaired.

[0068] In some embodiments, according to the ratio of the weld area of a single second weld mark to the designed area of the single second weld mark, the wear condition of the ultrasonic welding head is judged, including: the weld area of the single second weld mark is Sy, the designed area of the single second weld mark is S2, and when the ratio of Sy to S2 is less than 0.2, it is judged that the life of the ultrasonic welding head has reached.

[0069] In the above technical solution, by judging whether the ratio of the weld area S y of a single second weld mark to the designed area S2 of the single second weld mark is less than 0.2, the wear degree of the auxiliary welding teeth can be judged, so that it can be judged whether the life of the ultrasonic welding head has reached, and it is possible to simply and accurately judge whether the ultrasonic welding head should be replaced or repaired.

[0070] 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 including a first weld mark and a second weld mark, both the first weld mark and the second weld mark being formed as groove structures, the second weld mark being located between adjacent first weld marks, and the ratio range of the groove depth of the second weld mark to the groove depth of the first weld mark being 0.2 to 0.8.

[0071] In the above technical solution, by welding on the multi-layer tab ear pieces of the tab ears to form a first weld mark and a second weld mark that are both groove structures, during the welding process of the multi-layer tab ear pieces, the first weld mark and the second weld mark can weld and connect the multi-layer tab ear pieces, and make the second weld mark located between adjacent first weld marks and the groove depth of the second weld mark less than or equal to the groove depth of the first weld mark. When using this ultrasonic welding head to weld the multi-layer tab ear pieces, the first weld mark can play a main welding and connecting role. By adding a second weld mark between the first weld marks and the groove depth of the second weld mark being less than or equal to the groove depth of the first weld mark, the second weld mark can perform local strengthening welding on the un-welded areas between the layers of the multi-layer tab ear pieces, and can reduce the problem of local virtual welding of the tab ears and the problem of insufficient over-current area of the tab ears caused by the local virtual welding problem of the tab ears, which is beneficial to improving the service stability of the battery.

[0072] In the above technical solution, by making the ratio of the groove depth of the second weld mark to the groove depth of the first weld mark not less than 0.2, the second weld mark can effectively locally strengthen the welding of the un-welded area between layers of the multi-layer tab, improving the local strengthening welding effect; by making the ratio of the groove depth of the second weld mark to the groove depth of the first weld mark not greater than 0.8, the influence of the second weld mark on the first weld mark can be reduced. While the first weld mark plays a major welding role, the second weld mark cooperates with the first weld mark to effectively locally strengthen the welding of the un-welded area between the first weld marks, which can better reduce the problem of virtual welding and better improve the welding quality of the multi-layer tab.

[0073] In some embodiments, the weld mark area of a single second weld mark is smaller than the weld mark area of a single first weld mark.

[0074] In the above technical solution, by making the weld mark area of a single second weld mark smaller than the weld mark area of a single first weld mark, and the weld mark area of a single first weld mark being larger, a single first weld mark can play a better major welding role relative to a single second weld mark. The second weld mark cooperates with the first weld mark to effectively locally strengthen the welding of the un-welded area between the first weld marks, which can make the cooperation effect between the second weld mark and the first weld mark better, can better reduce the problem of virtual welding, and better improve the welding quality of the multi-layer tab.

[0075] In some embodiments, the ratio of the weld mark area of a single second weld mark to the weld mark area of a single first weld mark is 0.1 to 0.8.

[0076] In the above technical solution, by making the ratio of the weld mark area of a single second weld mark to the weld mark area of a single first weld mark not less than 0.1, the second weld mark can effectively locally strengthen the welding of the un-welded area between layers of the multi-layer tab, and the local strengthening area is larger, which helps to improve the local strengthening welding effect; by making the ratio of the weld mark area of a single second weld mark to the weld mark area of a single first weld mark not greater than 0.8, the influence of the second weld mark on the first weld mark can be reduced. While the first weld mark plays a major welding role, the second weld mark cooperates with the first weld mark to effectively locally strengthen the welding of the un-welded area between the first weld marks, which can better reduce the problem of virtual welding and better improve the welding quality of the multi-layer tab.

[0077] In some embodiments, the tab is connected to the electrode terminal through a connecting piece, and multiple layers of the tab are ultrasonically welded to the connecting piece.

[0078] In the above technical solution, the tab is connected to the electrode terminal through a connecting piece, which can facilitate the electrical connection between the tab and the electrode terminal. Moreover, by connecting the multi-layer tab pieces and the connecting piece through ultrasonic welding, the first weld mark can play a major role in the welding connection, and the second weld mark can perform local strengthening welding on the un-welded area between the layers of the multi-layer tab pieces, which can reduce the problem of local virtual welding of the tab and the problem of insufficient current-carrying area of the tab caused by the local virtual welding problem of the tab, improve the welding quality between the multi-layer tab pieces and the connecting piece, and since the welding area of the tab and the connecting piece is increased, the risk of local ablation of the battery electrode caused by excessive heat generation concentrated in the welding area of the tab and the connecting piece during the operation of the battery can be reduced, which is beneficial to improving the service stability of the battery.

[0079] In a fifth aspect, the present invention provides a battery device, comprising: a box body; a battery cell according to the battery cell of the fourth aspect embodiment of the present invention, and the battery cell is disposed in the box body.

[0080] In the above technical solution, by providing the above battery cell, the battery cell forms a first weld mark and a second weld mark both in a groove structure by welding on the multi-layer tab pieces of the tab. During the welding process of the multi-layer tab pieces, the first weld mark and the second weld mark can weld and connect the multi-layer tab pieces, and the second weld mark is located between adjacent first weld marks and the groove depth of the second weld mark is less than or equal to the groove depth of the first weld mark. When using the ultrasonic welding head to weld the multi-layer tab pieces, the first weld mark can play a major role in the welding connection. By adding the second weld mark between the first weld marks and the groove depth of the second weld mark is less than or equal to the groove depth of the first weld mark, the second weld mark can perform local strengthening welding on the un-welded area between the layers of the multi-layer tab pieces, which can reduce the problem of local virtual welding of the tab and the problem of insufficient current-carrying area of the tab caused by the local virtual welding problem of the tab, and is beneficial to improving the service stability of the battery.

[0081] In a sixth aspect, the present invention provides an electrical device, comprising the battery device according to the fifth aspect embodiment of the present invention.

[0082] In the above technical solution, by providing the above-mentioned electrical device, the battery cells of the electrical device are welded on the multi-layer tab pieces of the tab to form a first weld mark and a second weld mark that are both groove structures. During the welding process of the multi-layer tab pieces, the first weld mark and the second weld mark can weld and connect the multi-layer tab pieces, and the second weld mark is located between adjacent first weld marks and the groove depth of the second weld mark is less than or equal to the groove depth of the first weld mark. When using this ultrasonic welding head to weld the multi-layer tab pieces, the first weld mark can play a major role in welding and connecting. By adding the second weld mark between the first weld marks and the groove depth of the second weld mark is less than or equal to the groove depth of the first weld mark, the second weld mark can perform local strengthening welding on the un-welded areas between the layers of the multi-layer tab pieces, which can reduce the problem of local virtual welding of the tab and the problem of insufficient current-carrying area of the tab caused by the local virtual welding problem of the tab, and is beneficial to improving the service stability of the battery.

[0083] Additional aspects and advantages of the present invention will be given in part in the following description, become apparent in part from the following description, or be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0084] The above and / or additional aspects and advantages of the present invention will become apparent and be readily understood from the description of the embodiments in conjunction with the following drawings, in which: Figure 1 is a schematic diagram of an ultrasonic welding head according to some embodiments of the present invention; Figure 2 is Figure 1 an enlarged view of E in Figure 3 is Figure 1 the front view of the ultrasonic welding head in Figure 4 is Figure 3 an enlarged view of F in Figure 5 is Figure 1 a schematic diagram of the ultrasonic welding head welding the tab and the adapter plate in Figure 6 is Figure 5 an enlarged view of G in Figure 7 is Figure 1 the front view of the partial structure of the ultrasonic welding head in Figure 8 is Figure 7 an enlarged view of H in Figure 9 is the front view of the partial structure of an ultrasonic welding head according to some other embodiments of the present invention; Figure 10 is a schematic diagram of a battery cell according to some embodiments of the present invention; Figure 11Schematic diagram of a battery device according to some embodiments of the present invention; Figure 12 Schematic diagram of an electrical device according to some embodiments of the present invention.

[0085] Reference numerals: 100, ultrasonic welding head; 10, welding head body; 11, welding surface; 12, avoidance surface; 14, first channel; 15, second channel; 20, main welding teeth; 30, auxiliary welding teeth; 31, first auxiliary welding teeth; 32, second auxiliary welding teeth; 40, shaping welding teeth; 200, battery cell; 21, housing; 22, electrode terminal; 23, electrode assembly; 231, tab; 24, welding mark area; 241, first welding mark; 242, second welding mark; 25, adapter plate; 300, battery device; 50, box body; 400, electrical device; 60, vehicle body. Detailed implementation manners

[0086] 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.

[0087] Unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs; the terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention; the terms "including" and "having" and any variations thereof in the specification and claims of the present invention and the above drawings are intended to cover non-exclusive inclusion. The terms "first", "second", etc. in the specification 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.

[0088] 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 places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments.

[0089] In the description of the present invention, it should be noted that, unless otherwise clearly specified and defined, the terms "installed", "connected", "linked", and "attached" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be directly connected, or indirectly connected through an intermediate medium, and it may 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 circumstances.

[0090] The term "and / or" in the present invention is merely a correlative relationship describing the 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 associated objects before and after.

[0091] In the embodiments of the present invention, the same reference numerals represent 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 illustrative and should not constitute any limitation to the present invention.

[0092] The term "a plurality of" appearing in the present invention refers to two or more (including two).

[0093] In the embodiments of the present invention, if there is no special indication, all the embodiments and optional embodiments of the present invention can be combined with each other to form a new technical solution.

[0094] In the embodiments of the present invention, if there is no special indication, all the technical features and optional technical features of the present invention can be combined with each other to form a new technical solution.

[0095] 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 busbar 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 can be formed by bundling a plurality of battery cells with cable ties.

[0096] The battery device may be a battery pack, which 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 in the box body.

[0097] In an embodiment 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 buckled so that a closed space is formed inside the box body to accommodate the battery cell assembly. Here, "closed" 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.

[0098] In an embodiment of the present invention, the box body may be part of the chassis structure of a vehicle. For example, part of the box body may become at least part of the floor of the vehicle, or part of the box body may become at least part of the cross beam and longitudinal beam of the vehicle.

[0099] In an embodiment of the present invention, the battery cell may be a secondary battery, which refers to a battery cell that can be activated by charging after discharging to continue to be used; the battery cell may be a lithium-ion battery, a sodium-ion battery, a sodium-lithium-ion battery, a lithium metal battery, a sodium metal battery, a lithium-sulfur battery, a magnesium-ion battery, a nickel-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 may be in the shape of a cylinder, a flat body, a cuboid or other shapes, and the embodiments of the present invention are not limited thereto either. Generally, the battery cells are divided into three types according to the packaging method: cylindrical battery cells, square battery cells, and soft-pack battery cells, and the embodiments of the present invention are not limited thereto either.

[0100] As the smallest energy unit of the battery device, the battery cell includes a housing and an electrode assembly disposed inside the housing. The electrode assembly is a component in the battery cell where an electrochemical reaction occurs. The housing may contain one or more electrode assemblies. The electrode assembly is mainly formed by winding or laminating a positive electrode sheet and a negative electrode sheet, and generally a separator is provided between the positive electrode sheet and the negative electrode sheet. The parts of the positive electrode sheet and the negative electrode sheet having active substances constitute the main body of the electrode assembly, and the parts of the positive electrode sheet and the negative electrode sheet not having active substances respectively constitute the electrode tabs.

[0101] The positive electrode sheet may include a positive electrode current collector and a positive electrode film layer provided on at least one surface of the positive electrode current collector, and the positive electrode film layer includes a positive electrode active material.

[0102] As an example, the positive 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 current collector.

[0103] As an example, the positive current collector can be a metal foil or a composite current collector.

[0104] The negative electrode sheet may include a negative current collector and a negative electrode film layer disposed on at least one surface of the negative current collector, and the negative electrode film layer includes a negative active material.

[0105] As an example, the negative 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 current collector.

[0106] As an example, the negative current collector can be a metal foil, a foam metal or a composite current collector.

[0107] Currently, from the perspective of the development of the market situation, 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 plants, but also widely used in electric transportation tools such as electric bicycles, electric motorcycles, electric vehicles, and many fields such as aerospace. With the continuous expansion of the application field of power batteries, the market demand is also continuously increasing.

[0108] In the related art, the tab is an important component of the battery cell and plays an important role in carrying current. Usually, a connecting piece is used to connect the tab and the electrode terminal of the battery cell, so as to realize the electrical connection between the tab and the electrode terminal. Usually, ultrasonic welding is used in the battery to realize the welding connection between the multi-layer tab pieces and the connecting piece.

[0109] However, during the ultrasonic welding process of the multi-layer tab pieces and the connecting piece, poor welding problems such as virtual welding are likely to occur. Virtual welding will cause the current-carrying capacity of the tab to weaken, greatly reducing the charge and discharge capacity of the battery. Seriously, excessive heat may be generated in the welding area between the tab and the connecting piece, causing local ablation of the battery electrode sheet, and then affecting the service reliability of the battery. Therefore, how to improve the welding quality of the multi-layer tab pieces and the connecting piece and improve the service stability of the battery is a technical problem to be solved urgently.

[0110] Based on this, the present invention proposes an ultrasonic welding head, including: a welding head body, main welding teeth and auxiliary welding teeth. The welding head body has a welding surface. The main welding teeth protrude from the welding surface and the main welding teeth are a plurality of spaced apart. In the protruding direction of the welding teeth relative to the welding surface, the tooth height of the main welding teeth is h1. The auxiliary welding teeth protrude from the welding surface and the auxiliary welding teeth are located between adjacent main welding teeth. In the protruding direction of the welding teeth relative to the welding surface, the tooth height of the auxiliary welding teeth is h2; wherein, the ratio range of h2 to h1 is 0.2 to 0.8.

[0111] In the above ultrasonic welding head, by providing a plurality of main welding teeth arranged at intervals on the welding surface, when using the ultrasonic welding head to weld workpieces such as multi-layer tab pieces and adapter pieces, the main welding teeth can play a main welding connection role. By adding auxiliary welding teeth between the main welding teeth and the tooth height of the auxiliary welding teeth being less than or equal to that of the main welding teeth, the auxiliary welding teeth can perform local strengthening welding on the un-welded areas between the layers of the multi-layer foil, reducing the problem of local virtual welding of the tab and the problem of insufficient current-carrying area of the tab caused by the local virtual welding problem of the tab. The welding quality of the multi-layer tab piece and the adapter piece can be improved, and since the welding area of the tab and the adapter piece is increased, the risk of local ablation of the battery electrode caused by excessive heat concentration in the welding area of the tab and the adapter piece during the operation of the battery can be reduced, which is beneficial to improving the service stability of the battery.

[0112] In the above technical solution, by making the ratio of the tooth height h2 of the auxiliary welding teeth to the tooth height h1 of the main welding teeth not less than 0.2, the auxiliary welding teeth can perform effective local strengthening welding on the un-welded areas between the layers of the multi-layer foil, improving the local strengthening welding effect; by making the ratio of the tooth height h2 of the auxiliary welding teeth to the tooth height h1 of the main welding teeth not greater than 0.8, the influence of the auxiliary welding teeth on the main welding teeth can be reduced. While the main welding teeth play a main welding role, the auxiliary welding teeth cooperate with the main welding teeth to perform effective local strengthening welding on the un-welded areas between the main welding teeth, better reducing the virtual welding problem and better improving the welding quality of the multi-layer foil.

[0113] The battery device disclosed in the embodiments of the present invention can be used in electrical equipment 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, etc. 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.

[0114] The electrical device disclosed in the embodiments 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 vehicle, or an extended-range 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.

[0115] The following will refer to Figures 1 - 9 describe the ultrasonic welding head 100 according to an embodiment of the present invention.

[0116] Referring to Figures 1 - 4 , in a first aspect, the present invention provides an ultrasonic welding head 100, including: a welding head body 10, main welding teeth 20, and auxiliary welding teeth 30. The welding head body 10 has a welding surface 11. The main welding teeth 20 protrude from the welding surface 11 and are multiple and spaced apart. In the protruding direction of the welding teeth relative to the welding surface 11, the tooth height of the main welding teeth 20 is h1. The auxiliary welding teeth 30 protrude from the welding surface 11 and the auxiliary welding teeth 30 are located between adjacent main welding teeth 20. In the protruding direction of the welding teeth relative to the welding surface 11, the tooth height of the auxiliary welding teeth 30 is h2; wherein, the ratio of h2 to h1 is less than or equal to 1.

[0117] 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 amplitude-adjusted by 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 pressure, it is converted into heat energy through friction, so that the software in the welded part area is joined and welded together.

[0118] 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.

[0119] The main welding teeth 20 protruding from the welding surface 11 means that the main welding teeth 20 are provided on the welding surface 11 and protrude relative to the welding surface 11.

[0120] The auxiliary welding teeth 30 protruding from the welding surface 11 means that the auxiliary welding teeth 30 are provided on the welding surface 11 and protrude relative to the welding surface 11.

[0121] The auxiliary welding teeth 30 can be one or more, and the auxiliary welding teeth 30 can be arranged in the gaps between adjacent main welding teeth 20.

[0122] For example, the tooth height h2 of the auxiliary welding teeth 30 can be less than the tooth height h1 of the main welding teeth 20, that is, the ratio of the tooth height h2 of the auxiliary welding teeth 30 to the tooth height h1 of the main welding teeth 20 can be less than 1.

[0123] For example, the tooth height h2 of the auxiliary welding teeth 30 can be equal to the tooth height h1 of the main welding teeth 20, that is, the ratio of the tooth height h2 of the auxiliary welding teeth 30 to the tooth height h1 of the main welding teeth 20 can be equal to 1.

[0124] For example, the ratio of the tooth height h2 of the auxiliary welding teeth 30 to the tooth height h1 of the main welding teeth 20 can be matched according to the hardness of the foil to be welded. For example, for the welding of relatively soft foils such as aluminum foil / copper foil, the relationship between the tooth height h2 of the auxiliary welding teeth 30 and the tooth height h1 of the main welding teeth 20 can satisfy: (0.2 - 0.5)h1 ≤ h2 ≤ (0.6 - 1)h1; for the ultrasonic welding of relatively hard foils such as stainless steel / titanium foil, the relationship between the tooth height h2 of the auxiliary welding teeth 30 and the tooth height h1 of the main welding teeth 20 can satisfy: (0.2 - 0.5)h1 ≤ h2 ≤ h1.

[0125] In the above technical solution, by arranging a plurality of main welding teeth 20 spaced apart on the welding surface 11, when using the ultrasonic welding head 100 to weld workpieces of multi-layer tab 231 sheets and adapter plates 25 and other multi-layer foils, the main welding teeth 20 can play a main welding connection role. By adding auxiliary welding teeth 30 between the main welding teeth 20 and the tooth height of the auxiliary welding teeth 30 being less than or equal to that of the main welding teeth 20, the auxiliary welding teeth 30 can perform local strengthening welding on the un-welded areas between the multi-layer foils, which can reduce the problem of local virtual welding of the tab 231 and the problem of insufficient current-carrying area of the tab 231 caused by the local virtual welding problem of the tab 231, improve the welding quality of the multi-layer tab 231 sheets and the adapter plate 25, and since the welding area of the tab 231 and the adapter plate 25 increases, the risk of local ablation of the battery electrode sheet caused by over-concentrated heat generation in the welding area of the tab 231 and the adapter plate 25 during the operation of the battery can be reduced, which is beneficial to improving the service stability of the battery.

[0126] In some embodiments, referring to Figures 1 - 4 , the ratio range of h2 to h1 is 0.2 - 0.8.

[0127] For example, the ratio of the tooth height h2 of the auxiliary welding teeth 30 to the tooth height h1 of the main welding teeth 20 can be 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, etc.

[0128] In the above technical solution, by making the ratio of the tooth height h2 of the auxiliary welding teeth 30 to the tooth height h1 of the main welding teeth 20 not less than 0.2, the auxiliary welding teeth 30 can perform effective local strengthening welding on the un-welded areas between the multi-layer foils, improving the local strengthening welding effect; by making the ratio of the tooth height h2 of the auxiliary welding teeth 30 to the tooth height h1 of the main welding teeth 20 not greater than 0.8, the influence of the auxiliary welding teeth 30 on the main welding teeth 20 can be reduced. While the main welding teeth 20 play a main welding role, the auxiliary welding teeth 30 cooperate with the main welding teeth 20 to perform effective local strengthening welding on the un-welded areas between the main welding teeth 20, which can better reduce the virtual welding problem and better improve the welding quality of the multi-layer foils.

[0129] In some embodiments, referring to Figures 7 - 8, the projection of a single main welding tooth 20 on the welding surface 11 is the first projection, and the projection of a single auxiliary welding tooth 30 on the welding surface 11 is the second projection. The ratio of the area of the second projection to the area of the first projection is less than 1.

[0130] Among them, the projections of a single main welding tooth 20 and a single auxiliary welding tooth 30 on the welding surface 11 are both orthographic projections.

[0131] In the above technical solution, by making the ratio of the area of the projection of a single auxiliary welding tooth 30 on the welding surface 11 to the area of the projection of a single main welding tooth 20 on the welding surface 11 less than 1, the contact area between the main welding tooth 20 and the multi-layer foil is greater than the contact area between the auxiliary welding tooth 30 and the multi-layer foil. This can enable the main welding tooth 20 to play a better main welding role relative to the auxiliary welding tooth 30. The auxiliary welding tooth 30 cooperates with the main welding tooth 20 to perform effective local strengthening welding on the unwelded area between the main welding teeth 20, which can make the cooperation effect between the auxiliary welding tooth 30 and the main welding tooth 20 better, can better reduce the problem of false soldering, and can better improve the welding quality of the multi-layer foil.

[0132] In some embodiments, referring to Figures 7 - 8 , the ratio of the area of the second projection to the area of the first projection is 0.1 to 0.8.

[0133] For example, the ratio of the area of the second projection to the area of the first projection is 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, etc.

[0134] In the above technical solution, by making the ratio of the area of the projection of a single auxiliary welding tooth 30 on the welding surface 11 to the area of the projection of a single main welding tooth 20 on the welding surface 11 not less than 0.1, the auxiliary welding tooth 30 can perform effective local strengthening welding on the interlayer unwelded area of the multi-layer foil, and the local strengthening area is relatively large, which helps to improve the local strengthening welding effect. By making the ratio of the area of the projection of a single auxiliary welding tooth 30 on the welding surface 11 to the area of the projection of a single main welding tooth 20 on the welding surface 11 not more than 0.8, the influence of the auxiliary welding tooth 30 on the main welding tooth 20 can be reduced. While the main welding tooth 20 plays a main welding role, the auxiliary welding tooth 30 cooperates with the main welding tooth 20 to perform effective local strengthening welding on the unwelded area between the main welding teeth 20, which can better reduce the problem of false soldering and better improve the welding quality of the multi-layer foil.

[0135] In some embodiments, referring to Figures 7 - 8 , the projection of a single auxiliary welding tooth 30 on the welding surface 11 is the second projection. The surface of the main welding tooth 20 away from the welding surface 11 constitutes the tooth end face. The projection of a single tooth end face on the welding surface 11 is the third projection. The ratio of the area of the second projection to the area of the third projection is less than 1.

[0136] Among them, the projection of the end face of a single welding tooth on the welding surface 11 and the projection of a single auxiliary welding tooth 30 on the welding surface 11 are both orthographic projections.

[0137] In the above technical solution, by making the ratio of the area of the projection of a single auxiliary welding tooth 30 on the welding surface 11 to the area of the projection of the end face of a single main welding tooth 20 on the welding surface 11 less than 1, the contact area between the main welding tooth 20 and the multi-layer foil is greater than the contact area between the auxiliary welding tooth 30 and the multi-layer foil, so that the main welding tooth 20 can play a better main welding role relative to the auxiliary welding tooth 30. The auxiliary welding tooth 30 cooperates with the main welding tooth 20 to effectively locally strengthen the welding of the non-welded area between the main welding teeth 20, which can make the cooperation effect between the auxiliary welding tooth 30 and the main welding tooth 20 better, better reduce the problem of false soldering, and better improve the welding quality of the multi-layer foil.

[0138] In some embodiments, referring to Figures 7 - 8 , the ratio of the area of the second projection to the area of the third projection is 0.3 to 0.8.

[0139] For example, the ratio of the area of the second projection to the area of the third projection is 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, etc.

[0140] In the above technical solution, by making the ratio of the area of the projection of a single auxiliary welding tooth 30 on the welding surface 11 to the area of the projection of the end face of a single main welding tooth 20 on the welding surface 11 not less than 0.3, the auxiliary welding tooth 30 can effectively locally strengthen the welding of the non-welded area between the layers of the multi-layer foil, and the local strengthening area is large, which helps to improve the local strengthening welding effect; by making the ratio of the area of the projection of a single auxiliary welding tooth 30 on the welding surface 11 to the area of the projection of the end face of a single main welding tooth 20 on the welding surface 11 not greater than 0.8, the influence of the auxiliary welding tooth 30 on the main welding tooth 20 can be reduced. While the main welding tooth 20 plays a main welding role, the auxiliary welding tooth 30 cooperates with the main welding tooth 20 to effectively locally strengthen the welding of the non-welded area between the main welding teeth 20, which can better reduce the problem of false soldering and better improve the welding quality of the multi-layer foil.

[0141] In some embodiments, referring to Figures 7 - 8 , the projection of a single main welding tooth 20 on the welding surface 11 is the first projection, the projection of a single auxiliary welding tooth 30 on the welding surface 11 is the second projection, and the second projection and the first projection are arranged at intervals.

[0142] The second projection and the first projection being arranged at intervals means that there is no overlapping part and there is a gap between the second projection and the first projection.

[0143] In the above technical solution, by arranging the projection of a single auxiliary welding tooth 30 on the welding surface 11 at intervals from the projection of a single main welding tooth 20 on the welding surface 11, a gap can be formed between the auxiliary welding tooth 30 and the main welding tooth 20. When using the ultrasonic welding head 100 to weld workpieces such as multiple layers of tab 231 sheets and adapter sheets 25, the gap between the auxiliary welding tooth 30 and the main welding tooth 20 can reserve an overflow space for the overflow material during the welding process, reducing the problem of large local stress caused by overly concentrated overflow material and resulting in welding cracks, which is beneficial to further improving the welding quality.

[0144] In some embodiments, referring to Figures 7 - 8 , the minimum distance between the second projection and the first projection is d, the equivalent diameter of the second projection is D0, and the ratio of d to D0 is less than 0.35.

[0145] Wherein, the equivalent diameter of the second projection refers to the diameter of a circle having the same area as the second projection. For example, when the second projection is a circle, the diameter of the second projection is the equivalent diameter of the second projection.

[0146] For example, the ratio of d to D0 is 0.34, 0.32, 0.30, 0.28, 0.26, 0.24, 0.22, 0.20, 0.18, 0.16, 0.14, 0.12, 0.10, 0.08, 0.06, etc.

[0147] In the above technical solution, by making the distance d between the projection of a single auxiliary welding tooth 30 on the welding surface 11 and the projection of a single main welding tooth 20 on the welding surface 11 satisfy: the ratio of d to the equivalent diameter D0 of the projection of a single main welding tooth 20 on the welding surface 11 is less than 0.35, the distance between the projection of a single auxiliary welding tooth 30 on the welding surface 11 and the projection of a single main welding tooth 20 on the welding surface 11 can be made smaller. While reserving an overflow space for the overflow material during the welding process, it can enable the auxiliary welding tooth 30 to locally strengthen a larger area of the interlayer unwelded area between the main welding teeth 20, further reducing the area of the interlayer unwelded area of the multiple-layer foil, thereby further reducing the position or area of the virtual welding, and better reducing the virtual welding problem and better improving the welding quality of the multiple-layer foil.

[0148] In some embodiments, referring to Figures 7 - 8 , the ratio range of d to D0 is 0.1 - 0.25.

[0149] For example, the ratio of d to D0 is 0.25, 0.24, 0.22, 0.20, 0.18, 0.16, 0.14, 0.12, 0.10, etc.

[0150] In the above technical solution, by making the ratio of the distance d between the projection of a single auxiliary welding tooth 30 on the welding surface 11 and the projection of a single main welding tooth 20 on the welding surface 11 to the equivalent diameter D0 of the projection of a single main welding tooth 20 on the welding surface 11 not less than 0.1, a relatively sufficient overflow space can be reserved for the overflow material during the welding process, so as to better reduce the problem of large local stress caused by overly concentrated overflow material and resulting in welding cracks; and, by making the ratio of the distance d between the projection of a single auxiliary welding tooth 30 on the welding surface 11 and the projection of a single main welding tooth 20 on the welding surface 11 to the equivalent diameter D0 of the projection of a single main welding tooth 20 on the welding surface 11 not greater than 0.25, the auxiliary welding tooth 30 can locally strengthen a larger area of the interlayer unwelded area between the main welding teeth 20, further reducing the area of the interlayer unwelded area of the multi-layer foil, thereby further reducing the position or area of the virtual welding, and better reducing the problem of virtual welding and better improving the welding quality of the multi-layer foil.

[0151] In some embodiments, referring to Figures 7 - 8 , a plurality of main welding teeth 20 are arranged in multiple rows and columns. The multiple columns of main welding teeth 20 are arranged along a first direction, and the multiple rows of main welding teeth 20 are arranged along a second direction. The first direction intersects the second direction. A first channel 14 is formed between adjacent two columns of main welding teeth 20, and a second channel 15 is formed between adjacent two rows of main welding teeth 20. The first channel 14 intersects the second channel 15, and the first channel 14 and / or the second channel 15 are provided with auxiliary welding teeth 30.

[0152] For example, the first direction may refer to the e1 direction in the attached drawing, and the second direction may refer to the e2 direction in the attached drawing.

[0153] For example, the welding surface 11 may be rectangular, the first direction may be the length direction of the welding surface 11, and the second direction may be the width direction of the welding surface 11.

[0154] In the above technical solution, by arranging a plurality of main welding teeth 20 in multiple rows and columns, the welding connections of the main welding teeth 20 can be made at different positions of the multi-layer foil, reducing the area of the interlayer unwelded area of the multi-layer foil, which is beneficial to reducing the problem of virtual welding; and, by arranging the auxiliary welding teeth 30 between adjacent two columns or adjacent two rows of main welding teeth 20, the auxiliary welding teeth 30 can locally strengthen the welding of the interlayer unwelded area between adjacent two columns or adjacent two rows of main welding teeth 20, reducing the problem of virtual welding and improving the welding quality of the multi-layer foil.

[0155] In some embodiments, referring to Figures 7 - 8, the projection of a single auxiliary welding tooth 30 on the welding surface 11 is the second projection, the projection of a single first channel 14 on the welding surface 11 is the fourth projection, the projection of a single second channel 15 on the welding surface 11 is the fifth projection, the maximum dimension of the second projection in the first direction is D1, the maximum dimension of the second projection in the second direction is D2, the width dimension of the fourth projection in the first direction is W1, and the width dimension of the fifth projection in the second direction is W2; wherein, the ratio of D1 to W1 is greater than 0.8 and / or the ratio of D2 to W2 is greater than 0.8.

[0156] Among them, the ratio of D1 to W1 being greater than 0.8 and / or the ratio of D2 to W2 being greater than 0.8 can include the following situations: for example, the ratio of D1 to W1 is greater than 0.8; for example, the ratio of D2 to W2 is greater than 0.8; for example, the ratio of D1 to W1 is greater than 0.8 and the ratio of D2 to W2 is greater than 0.8.

[0157] For example, the ratio of D1 to W1 can be 0.82, 0.84, 0.86, 0.88, 0.9, 0.92, 0.94, 0.96, 0.98, 1.0, 1.2, 1.4, 1.6, 1.8, 2.0, 2.2, 2.4, 2.6, 2.8, 3.0, etc.

[0158] For example, the ratio of D2 to W2 can be 0.82, 0.84, 0.86, 0.88, 0.9, 0.92, 0.94, 0.96, 0.98, 1.0, 1.2, 1.4, 1.6, 1.8, 2.0, 2.2, 2.4, 2.6, 2.8, 3.0, etc.

[0159] In the above technical solution, by making the ratio of the dimension of the projection of the auxiliary welding tooth 30 on the welding surface 11 in the arrangement direction of the plurality of main welding teeth 20 to the width dimension of the first channel 14 or the second channel 15 formed between the plurality of main welding teeth 20 in the arrangement direction of the plurality of main welding teeth 20 greater than 0.8, the size of the auxiliary welding tooth 30 can be made larger, and the auxiliary welding tooth 30 can perform local strengthening welding on a larger area of the interlayer unwelded area between two adjacent columns or two adjacent rows of main welding teeth 20, better reducing the problem of false welding and further improving the welding quality of the multi-layer foil.

[0160] In some embodiments, referring to Figures 7 - 8 , an auxiliary welding tooth 30 is provided at the intersection of the first channel 14 and the second channel 15.

[0161] An auxiliary welding tooth 30 is provided at the intersection of the first channel 14 and the second channel 15, which can be that an auxiliary welding tooth 30 is provided at a partial intersection of the first channel 14 and the second channel 15, or an auxiliary welding tooth 30 is provided at all intersections of the first channel 14 and the second channel 15.

[0162] In the above technical solution, during the welding process of multiple-layer foils using the ultrasonic welding head 100, the overflow of materials is relatively severe and the material arch is relatively high at the position corresponding to the intersection of the first channel 14 and the second channel 15 in the multiple-layer foils. Therefore, the risk of false soldering is relatively high. By providing auxiliary welding teeth 30 at the intersection of the first channel 14 and the second channel 15 formed between multiple main welding teeth 20, the auxiliary welding teeth 30 can compact the position where the overflow of materials is relatively severe and the material arch is relatively high. Through local strengthening welding of the area with a relatively high risk of false soldering by the auxiliary welding teeth 30, the problem of false soldering can be better reduced, and further the welding quality of the multiple-layer foils can be improved.

[0163] In some embodiments, referring to Figures 7 - 8 , the projection of a single auxiliary welding tooth 30 on the welding surface 11 is the second projection, the projection of a single first channel 14 on the welding surface 11 is the fourth projection, and the projection of a single second channel 15 on the welding surface 11 is the fifth projection. The maximum dimension of the second projection in the first direction is D1, the maximum dimension of the second projection in the second direction is D2, the width dimension of the fourth projection in the first direction is W1, and the width dimension of the fifth projection in the second direction is W2. The ratio of W1 to W2 is greater than 1; wherein, the auxiliary welding teeth 30 provided at the intersection of the first channel 14 and the second channel 15 satisfy that the ratio of D2 to W2 is greater than 1.

[0164] For example, the ratio of W1 to W2 can be 1.2, 1.4, 1.6, 1.8, 2.0, 2.2, 2.4, 2.6, 2.8, 3.0, 3.2, 3.4, 3.6, 3.8, 4.0, 4.2, 4.4, 4.6, 4.8, 5.0, etc.

[0165] For example, the ratio of D2 to W2 can be 1.2, 1.4, 1.6, 1.8, 2.0, 2.2, 2.4, 2.6, 2.8, 3.0, 3.2, 3.4, 3.6, 3.8, 4.0, etc.

[0166] In the above technical solution, by making the width ratio of the first channel 14 and the second channel 15 formed between multiple main welding teeth 20 greater than 1, and making the auxiliary welding teeth 30 provided at the intersection of the first channel 14 and the second channel 15 satisfy that the ratio of the maximum D2 of the projection of the auxiliary welding teeth 30 on the welding surface 11 in the second direction to the width W2 of the second channel 15 in the second direction is greater than 1, the relatively large width space of the first channel 14 can be fully utilized, so that the size of the auxiliary welding teeth 30 can be set larger. Thus, the auxiliary welding teeth 30 can perform local strengthening welding on a relatively large area of the interlayer non-welded area between multiple main welding teeth 20, better reducing the problem of false soldering and further improving the welding quality of the multiple-layer foils.

[0167] In some embodiments, referring to Figures 7 - 8, the auxiliary welding teeth 30 provided at the intersection of the first channel 14 and the second channel 15 satisfy that the ratio range of D2 to W2 is 1.5 to 3.

[0168] For example, the ratio of D2 to W2 can be 1.5, 1.6, 1.8, 2.0, 2.2, 2.4, 2.6, 2.8, 3.0, etc.

[0169] In the above technical solution, by making the auxiliary welding teeth 30 provided at the intersection of the first channel 14 and the second channel 15 satisfy that the ratio of the maximum D2 in the second direction of the projection of the auxiliary welding teeth 30 on the welding surface 11 to the width W2 of the second channel 15 in the second direction is not less than 1.5, the relatively large width space of the first channel 14 can be fully utilized, so that the size of the auxiliary welding teeth 30 can be set larger, thereby enabling the auxiliary welding teeth 30 to perform local strengthening welding on a relatively large area of the interlayer unwelded area between multiple main welding teeth 20, better reducing the problem of virtual welding, and further improving the welding quality of the multi-layer foil; by making the auxiliary welding teeth 30 provided at the intersection of the first channel 14 and the second channel 15 satisfy that the ratio of the maximum D2 in the second direction of the projection of the auxiliary welding teeth 30 on the welding surface 11 to the width W2 of the second channel 15 in the second direction is not greater than 3, while fully utilizing the relatively large width space of the first channel 14 and setting the size of the auxiliary welding teeth 30 larger, the adhesion problem caused by the excessive contact area between the ultrasonic welding head 100 and the workpiece due to the too large size of the auxiliary welding teeth 30 can be reduced. Thus, while taking into account that the auxiliary welding teeth 30 perform local strengthening welding on a relatively large area of the interlayer unwelded area between multiple main welding teeth 20, better reducing the problem of virtual welding, and further improving the welding quality of the multi-layer foil, the adhesion problem between the ultrasonic welding head 100 and the workpiece can be reduced.

[0170] In some embodiments, referring to Figures 7 - 8 , the auxiliary welding teeth 30 provided at the intersection of the first channel 14 and the second channel 15 satisfy that the ratio of D1 to W1 is less than 1.

[0171] For example, the ratio of D1 to W1 can be 0.76, 0.78, 0.80, 0.82, 0.84, 0.86, 0.88, 0.9, 0.92, 0.94, 0.96, 0.98.

[0172] In the above technical solution, the auxiliary welding tooth 30 arranged at the intersection of the first channel 14 and the second channel 15 satisfies: the ratio of the maximum D1 of the projection of the auxiliary welding tooth 30 on the welding surface 11 in the first direction to the width W1 of the first channel 14 in the first direction is less than 1. In this way, the larger width space of the first channel 14 is fully utilized to make the size of the auxiliary welding tooth 30 larger. At the same time, a gap can be left between the auxiliary welding tooth 30 and the main welding tooth 20 in the first direction to provide an overflow space for the overflow generated during the welding process. In this way, the auxiliary welding tooth 30 can be used to perform local strengthening welding of a larger area of the unwelded area between the layers of multiple main welding teeth 20, so as to better reduce the problem of cold welding, further improve the welding quality of multi-layer foils, and reduce the problem of welding cracks caused by excessive concentration of overflow.

[0173] In some embodiments, reference Figures 7 - 8 , the number of columns of the main welding teeth 20 is greater than the number of rows of the main welding teeth 20.

[0174] For example, the number of columns of the main welding teeth 20 may be eleven columns, and the number of rows of the main welding teeth 20 may be three rows.

[0175] In the above technical solution, by making the number of columns of the main welding teeth 20 greater than the number of rows of the main welding teeth 20, the number of first channels 14 formed between the multiple main welding teeth 20 can be larger. Since the number of first channels 14 with larger widths is larger, more arrangement space can be provided for more auxiliary welding teeth 30 and the size of the auxiliary welding teeth 30 can be larger, which is more conducive to the auxiliary welding teeth 30 cooperating with the main welding teeth 20, and effective local strengthening welding is performed on the unwelded areas between the main welding teeth 20, which can better reduce the problem of cold welding and better improve the welding quality of multi-layer foil.

[0176] In some embodiments, reference Figure 9 There are multiple auxiliary welding teeth 30, and the multiple auxiliary welding teeth 30 include a first auxiliary welding tooth 31, which is arranged at the intersection of the first channel 14 and the second channel 15. The multiple auxiliary welding teeth 30 also include at least one of a second auxiliary welding tooth 32 and a third auxiliary welding tooth, the second auxiliary welding tooth 32 is arranged in the first channel 14 and is staggered with the intersection position of the first channel 14 and the second channel 15, and the third auxiliary welding tooth is arranged in the second channel 15 and is staggered with the intersection position of the first channel 14 and the second channel 15; wherein, in the protruding direction of the welding teeth relative to the welding surface 11, the tooth heights of the second auxiliary welding teeth 32 and the third auxiliary welding teeth are both smaller than the tooth height of the first auxiliary welding tooth 31.

[0177] Among them, in the protruding direction of the welding teeth relative to the welding surface 11, the tooth heights of the second auxiliary welding teeth 32 and the third auxiliary welding teeth are both smaller than the tooth height of the first auxiliary welding teeth 31, which means that in the protruding direction of the welding teeth relative to the welding surface 11, the tooth height of the second auxiliary welding teeth 32 is smaller than the tooth height of the first auxiliary welding teeth 31, and the tooth height of the third auxiliary welding teeth is smaller than the tooth height of the first auxiliary welding teeth 31.

[0178] In the above technical solution, by providing multiple auxiliary welding teeth 30, local strengthening welding can be performed on the interlayer unwelded areas at multiple different positions, which can better reduce the problem of false soldering. Moreover, the multiple auxiliary welding teeth 30 include the first auxiliary welding teeth 31 provided at the intersection of the first channel 14 and the second channel 15. The first auxiliary welding teeth 31 can compact the position where the overflow is relatively serious and the material bulges relatively high. By locally strengthening the welding of the areas with a relatively high risk of false soldering through the auxiliary welding teeth 30, the problem of false soldering can be better reduced, and the welding quality of the multi-layer foil can be further improved. In addition, the multiple auxiliary welding teeth 30 further include at least one of the second auxiliary welding teeth 32 and the third auxiliary welding teeth. The second auxiliary welding teeth 32 are provided in the first channel 14 and are staggered from the intersection position of the first channel 14 and the second channel 15. The second auxiliary welding teeth 32 can perform local strengthening welding on the interlayer unwelded area between two adjacent columns of main welding teeth 20. The third auxiliary welding teeth are provided in the second channel 15 and are staggered from the intersection position of the first channel 14 and the second channel 15. The third auxiliary welding teeth can perform local strengthening welding on the interlayer unwelded area between two adjacent rows of main welding teeth 20.

[0179] In addition, at the intersection position of the multi-layer foil corresponding to the first channel 14 and the second channel 15, compared with other positions of the first channel 14 and the second channel 15, the overflow is more serious and the arching height is higher. The tooth height of the first auxiliary welding teeth 31 is relatively high, and the tooth heights of the second auxiliary welding teeth 32 and the third auxiliary welding teeth are relatively small, which can better match the specific conditions of the corresponding positions of the multi-layer foil. While realizing local strengthening welding of multiple interlayer unwelded areas between multiple main welding teeth 20, the problem of false soldering can be better reduced, and the welding quality of the multi-layer foil can be further improved. Moreover, the problem of welding cracks caused by excessive local stress due to overly concentrated overflow can be reduced, and the welding quality can be further improved.

[0180] In some embodiments, refer to Figure 9There are multiple auxiliary welding teeth 30, and the multiple auxiliary welding teeth 30 include a first auxiliary welding tooth 31, which is arranged at the intersection of the first channel 14 and the second channel 15. The multiple auxiliary welding teeth 30 also include at least one of a second auxiliary welding tooth 32 and a third auxiliary welding tooth, the second auxiliary welding tooth 32 is arranged in the first channel 14 and is staggered with the intersection position of the first channel 14 and the second channel 15, and the third auxiliary welding tooth is arranged in the second channel 15 and is staggered with the intersection position of the first channel 14 and the second channel 15; wherein the projection area of a single second auxiliary welding tooth 32 and a single third auxiliary welding tooth on the welding surface 11 are both smaller than the projection area of a single first auxiliary welding tooth 31 on the welding surface 11.

[0181] Among them, the projection area of a single second auxiliary welding tooth 32 and a single third auxiliary welding tooth on the welding surface 11 are both smaller than the projection area of a single first auxiliary welding tooth 31 on the welding surface 11, which means that the projection area of a single second auxiliary welding tooth 32 on the welding surface 11 is smaller than the projection area of a single first auxiliary welding tooth 31 on the welding surface 11, and the projection area of a single third auxiliary welding tooth on the welding surface 11 is smaller than the projection area of a single first auxiliary welding tooth 31 on the welding surface 11.

[0182] In the above technical solution, by providing a plurality of auxiliary welding teeth 30, local reinforcement welding can be performed on the unwelded areas between layers at multiple different positions, which can better reduce the problem of cold welding; and the plurality of auxiliary welding teeth 30 include a first auxiliary welding tooth 31 provided at the intersection of the first channel 14 and the second channel 15. The first auxiliary welding tooth 31 can compact the position where the overflow is more serious and the material is arched higher. By using the auxiliary welding teeth 30, local reinforcement welding is performed on the position where the risk of cold welding is higher, which can better reduce the problem of cold welding and further improve the reliability of the multi-layer foil. Welding quality; and, the plurality of auxiliary welding teeth 30 further include at least one of a second auxiliary welding tooth 32 and a third auxiliary welding tooth, the second auxiliary welding tooth 32 being arranged in the first channel 14 and being staggered with the intersection position of the first channel 14 and the second channel 15, the second auxiliary welding tooth 32 can perform local strengthening welding on the interlayer unwelded area between two adjacent rows of main welding teeth 20, the third auxiliary welding tooth being arranged in the second channel 15 and being staggered with the intersection position of the first channel 14 and the second channel 15, the third auxiliary welding tooth can perform local strengthening welding on the interlayer unwelded area between two adjacent rows of main welding teeth 20.

[0183] In addition, at the intersection position of the multi-layer foil corresponding to the first channel 14 and the second channel 15, compared with other positions of the first channel 14 and the second channel 15, the overflow of materials is more serious and the arching height is higher. The projected area of the first auxiliary welding tooth 31 on the welding surface 11 is larger, while the projected areas of the second auxiliary welding tooth 32 and the third auxiliary welding tooth on the welding surface 11 are smaller, which can better match the specific conditions of the corresponding positions of the multi-layer foil. It can realize local strengthening welding of the interlayer unwelded areas between multiple main welding teeth 20, better reduce the problem of false welding, further improve the welding quality of the multi-layer foil, and can reduce the problem of large local stress caused by too concentrated overflow of materials, resulting in welding crack problems, and further improve the welding quality. Moreover, it can also reduce the adhesion problem caused by the too large contact area between the ultrasonic welding head 100 and the workpiece. Therefore, while taking into account that the auxiliary welding teeth 30 perform large-area local strengthening welding on the interlayer unwelded areas between multiple main welding teeth 20, better reduce the problem of false welding, and further improve the welding quality of the multi-layer foil, the adhesion problem between the ultrasonic welding head 100 and the workpiece can be reduced.

[0184] In some embodiments, referring to Figures 3 - 6 , in the protruding direction of the welding teeth relative to the welding surface 11, the cross-sectional area of the main welding teeth 20 gradually decreases.

[0185] Wherein, the cross-sectional area of the main welding teeth 20 refers to the cross-section obtained by cutting the main welding teeth 20 with a plane parallel to the welding surface 11.

[0186] In the above technical solution, by making the cross-sectional area of the main welding teeth 20 gradually decrease in the protruding direction of the welding teeth relative to the welding surface 11, when the welding pressure is constant, the pressure of the main welding teeth 20 on the multi-layer foil can be made larger, which is beneficial to enhancing the welding connection strength between the multi-layer foils and improving the firmness of the welding connection between the multi-layer foils.

[0187] In some embodiments, referring to Figures 3 - 6 , in the protruding direction of the welding teeth relative to the welding surface 11, the cross-sectional area of the auxiliary welding teeth 30 gradually decreases.

[0188] Wherein, the cross-sectional area of the auxiliary welding teeth 30 refers to the cross-section obtained by cutting the auxiliary welding teeth 30 with a plane parallel to the welding surface 11.

[0189] In the above technical solution, by making the cross-sectional area of the auxiliary welding teeth 30 gradually decrease in the protruding direction of the welding teeth relative to the welding surface 11, when the welding pressure is constant, the pressure of the auxiliary welding teeth 30 on the multi-layer foil can be made larger, which can better realize local strengthening welding of the interlayer unwelded areas between the main welding teeth 20, reduce the problem of false welding, and improve the welding quality of the multi-layer foil.

[0190] In some embodiments, referring to Figure 2, the main welding tooth 20 is in the shape of a frustum or a sphere.

[0191] In the above technical solution, by setting the main welding tooth 20 to be in the shape of a frustum or a sphere, the structure of the main welding tooth 20 can be made simple, which is convenient for processing and manufacturing; moreover, under a certain welding pressure, the main welding tooth 20 of this structural form can generate a relatively large pressure on the multi-layer foil, which is beneficial to enhancing the welding connection strength between the multi-layer foils and improving the firmness of the welding connection between the multi-layer foils.

[0192] In some embodiments, referring to Figure 2 , the auxiliary welding tooth 30 is spherical.

[0193] In the above technical solution, by setting the auxiliary welding tooth 30 to be spherical, the structure of the auxiliary welding tooth 30 can be made simple, which is convenient for processing and manufacturing; moreover, the shape of the overflow area between the spherical auxiliary welding tooth 30 and the adjacent main welding tooth 20 is relatively matched, which can better compact the overflow area between the adjacent main welding teeth 20. The overflow area also belongs to the non-welded area between layers, and can also better perform local strengthening welding on the overflow area.

[0194] In some embodiments, referring to Figure 2 , an avoidance surface 12 is formed on the welding head body 10. The avoidance surface 12 is located on the outer peripheral side of the welding surface 11 and is connected to the welding surface 11. The angle between the avoidance surface 12 and the welding surface 11 is an obtuse angle, and the avoidance surface 12 and the welding surface 11 are smoothly transitioned through an arc surface. A shaping welding tooth 40 is provided at the connection between the avoidance surface 12 and the welding surface 11.

[0195] In the above technical solution, by providing an inclined avoidance surface 12 on the welding head body 10 at the position on the outer peripheral side of the welding surface 11, and the angle between the avoidance surface 12 and the welding surface 11 is an obtuse angle, the avoidance surface 12 can be used to avoid the warping of the edge area of the multi-layer foil caused by the local pressurization of the multi-layer foil by the welding head body 10 during the welding process, and can reduce the acting force between the welding head body 10 and the upper edge area of the multi-layer foil, so that the welding head body 10 is not easy to cut the multi-layer foil during the welding process, and can effectively improve the problem of welding cracking of the multi-layer foil; moreover, a shaping welding tooth 40 is provided at the connection between the avoidance surface 12 and the welding surface 11, and the shaping welding tooth 40 has a pre-pressing and shaping effect on the multi-layer foil, which is convenient for the main welding tooth 20 and the auxiliary welding tooth 30 on the welding surface 11 to contact the surface of the multi-layer foil.

[0196] In the second aspect, the present invention provides an ultrasonic welding device, including: the ultrasonic welding head 100 of the first aspect embodiment of the present invention above.

[0197] In the above technical solution, by providing the ultrasonic welding head 100 described above, the ultrasonic welding head 100 is provided with a plurality of main welding teeth 20 arranged at intervals on the welding surface 11. When using the ultrasonic welding head 100 to weld workpieces such as multiple layers of tab 231 sheets and adapter sheets 25, the main welding teeth 20 can play a main welding connection role. By adding auxiliary welding teeth 30 between the main welding teeth 20 and the tooth height of the auxiliary welding teeth 30 being less than or equal to that of the main welding teeth 20, the auxiliary welding teeth 30 can perform local strengthening welding on the un-welded areas between the multiple layers of foils, reducing the problem of local false soldering of the tab 231 and the problem of insufficient current-carrying area of the tab 231 caused by the local false soldering of the tab 231, improving the welding quality of the multiple layers of tab 231 sheets and the adapter sheet 25, and since the welding area of the tab 231 and the adapter sheet 25 is increased, the risk of local ablation of the battery electrode plate caused by excessive heat concentration in the welding area of the tab 231 and the adapter sheet 25 during the operation of the battery can be reduced, which is beneficial to improving the service stability of the battery.

[0198] In a third aspect, referring to Figures 5 - 6 , the present invention provides a method for detecting wear of an ultrasonic welding head 100. The ultrasonic welding head 100 is the ultrasonic welding head 100 in the first aspect embodiment of the present invention. The method for detecting wear of the ultrasonic welding head 100 includes: Using the ultrasonic welding head 100 to perform ultrasonic pre-welding on a workpiece sample. The weld mark corresponding to the main welding tooth 20 on the workpiece sample is the first weld mark 241, and the weld mark corresponding to the auxiliary welding tooth 30 on the workpiece sample is the second weld mark 242; Identifying the first weld mark 241 and / or the second weld mark 242 formed on the workpiece sample; Calculating the weld mark area of a single first weld mark 241 and / or calculating the weld mark area of a single second weld mark 242; Judging the wear condition of the ultrasonic welding head 100 according to the weld mark area of the single first weld mark 241 and / or the weld mark area of the single second weld mark 242.

[0199] Among them, the workpiece sample can be multiple layers of foils.

[0200] The weld mark corresponding to the main welding tooth 20 on the workpiece sample is the first weld mark 241. The shape and area of the first weld mark 241 depend on the shape and size of the main welding tooth 20. The weld mark area of the first weld mark 241 can reflect the wear condition of the main welding tooth 20, and thus can reflect the wear condition of the ultrasonic welding head 100.

[0201] The weld mark corresponding to the auxiliary welding tooth 30 on the workpiece sample is the second weld mark 242. The shape and area of the second weld mark 242 depend on the shape and size of the auxiliary welding tooth 30. The weld mark area of the second weld mark 242 can reflect the wear condition of the auxiliary welding tooth 30, and thus can reflect the wear condition of the ultrasonic welding head 100.

[0202] For example, the second weld mark 242 formed on the workpiece sample can be identified manually or by a machine.

[0203] The first weld mark 241 and / or the second weld mark 242 refer to at least one of the first weld mark 241 and the second weld mark 242.

[0204] Calculating the weld mark area of a single first weld mark 241 and / or calculating the weld mark area of a single second weld mark 242 means calculating the weld mark area of at least one of the single first weld mark 241 and the single second weld mark 242.

[0205] In the above technical solution, by calculating the weld mark area of a single first weld mark 241 corresponding to the main welding tooth 20 formed on the workpiece sample and / or calculating the weld mark area of a single second weld mark 242 corresponding to the auxiliary welding tooth 30, the wear condition of the main welding tooth 20 and / or the auxiliary welding tooth 30 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 problems such as poor welding of multi-layer foils caused by wear of the ultrasonic welding head 100, such as false welding. Therefore, effective monitoring of false welding can be achieved, which helps to improve the welding quality of the ultrasonic welding head 100 for multi-layer foils, and thus can improve the quality reliability and stability of ultrasonic weld marks, and further improve the service reliability of the battery.

[0206] In some embodiments, identifying the first weld mark 241 and / or the second weld mark 242 formed on the workpiece sample includes: Collecting a weld mark image on the side of the workpiece sample where the weld mark is formed; Identifying the first weld mark 241 and / or the second weld mark 242 in the weld mark image.

[0207] For example, a 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.

[0208] For example, a calibration plate can be used to calibrate the camera to convert camera pixels into actual distances; the first weld mark 241 and / or the second weld mark 242 in the weld mark image can be identified by the software find_circle tool.

[0209] In the above technical solution, by collecting a weld mark image on the side of the workpiece sample where the weld mark is formed and identifying the first weld mark 241 and / or the second weld mark 242 in the weld mark image, the first weld mark 241 and / or the second weld mark 242 can be conveniently identified and found.

[0210] In some embodiments, calculating the weld mark area of a single first weld mark 241 includes: identifying the outer contour of the single first weld mark 241; calculating the area of the figure enclosed by the outer contour of the first weld mark 241.

[0211] Among them, the area of the figure enclosed by the outer contour of the first weld mark 241 is the weld mark area of the first weld mark 241.

[0212] For example, the software uses the Distance_PP operator to calculate the area of the figure enclosed by the outer contour of the first weld mark 241.

[0213] In the above technical solution, by first identifying the outer contour of the single first weld mark 241 and then calculating the area of the figure enclosed by the outer contour of the first weld mark 241, the weld mark area of the first weld mark 241 can be conveniently calculated. The calculation method of this weld mark area is simple and the calculation result is relatively accurate.

[0214] In some embodiments, calculating the weld mark area of a single second weld mark 242 includes: identifying the outer contour of the single second weld mark 242; calculating the area of the figure enclosed by the outer contour of the second weld mark 242.

[0215] Among them, the area of the figure enclosed by the outer contour of the second weld mark 242 is the weld mark area of the second weld mark 242.

[0216] 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 242.

[0217] In the above technical solution, by first identifying the outer contour of the single second weld mark 242 and then calculating the area of the figure enclosed by the outer contour of the second weld mark 242, the weld mark area of the second weld mark 242 can be conveniently calculated. The calculation method of this weld mark area is simple and the calculation result is relatively accurate.

[0218] In some embodiments, judging the wear condition of the ultrasonic welding head 100 according to the weld mark area of a single first weld mark 241 includes: judging the wear condition of the ultrasonic welding head 100 according to the ratio of the weld mark area of the single first weld mark 241 to the designed area of the single first weld mark 241.

[0219] Among them, during the long-term use of the ultrasonic welding head 100, the main welding teeth 20 will be gradually worn, and the weld mark area of the first weld mark 241 corresponding to the main welding teeth 20 will also gradually decrease. According to the ratio relationship between the weld mark area of a single main weld mark and the designed area of a single main weld mark, the wear condition of the main welding teeth 20 can be relatively accurately judged, and the wear degree of the ultrasonic welding head 100 can also be judged.

[0220] In the above technical solution, by comparing the ratio of the welding area of a single first weld mark 241 to its designed area, the reduction in the welding area of the current first weld mark 241 relative to its designed area can be obtained. The reduction in the welding area of the first weld mark 241 relative to its designed area can intuitively reflect the wear condition of the main welding teeth 20, thereby reflecting the wear condition of the ultrasonic welding head 100, which helps improve the accuracy of judging the wear condition of the ultrasonic welding head 100.

[0221] In some embodiments, to judge the wear condition of the ultrasonic welding head 100 based on the welding area of a single second weld mark 242, it includes: judging the wear condition of the ultrasonic welding head 100 according to the ratio of the welding area of a single second weld mark 242 to its designed area.

[0222] During the long-term use of the ultrasonic welding head 100, the auxiliary welding teeth 30 will be gradually worn, and the welding area of the second weld mark 242 corresponding to the auxiliary welding teeth 30 will also gradually decrease. According to the ratio relationship between the welding area of a single second weld mark 242 and its designed area, the wear condition of the auxiliary welding teeth 30 can be accurately judged, and the wear degree of the ultrasonic welding head 100 can also be judged.

[0223] In the above technical solution, by comparing the ratio of the welding area of a single second weld mark 242 to its designed area, the reduction in the welding area of the current second weld mark 242 relative to its designed area can be obtained. The reduction in the welding area of the second weld mark 242 relative to its designed area can intuitively reflect the wear condition of the auxiliary welding teeth 30, thereby reflecting the wear condition of the ultrasonic welding head 100, which helps improve the accuracy of judging the wear condition of the ultrasonic welding head 100.

[0224] In some embodiments, to judge the wear condition of the ultrasonic welding head 100 according to the ratio of the welding area of a single first weld mark 241 to its designed area, it includes: when the welding area of a single first weld mark 241 is Sx and the designed area of a single first weld mark 241 is S1, if the ratio of Sx to S1 is less than 0.2, it is judged that the life of the ultrasonic welding head 100 has reached.

[0225] The designed area of a single first weld mark 241 refers to: when the ultrasonic welding head 100 is first tested, the welding area formed by the main welding teeth 20 on the workpiece sample, and this welding area can be obtained by using the above calculation method.

[0226] For example, when the ratio of Sx to S1 is 0.3, it is determined that the lifespan of the ultrasonic welding head 100 has not reached its end, and it can continue to be used; when the ratio of Sx to S1 is 0.18, it is determined that the lifespan of the ultrasonic welding head 100 has reached its end, and its continued use is stopped.

[0227] For example, when the lifespan of the ultrasonic welding head 100 has not reached its end and it can continue to be used, the relationship between Sx and S1 can be matched and designed according to the hardness of the foil material. For example, for welding of relatively soft foil materials such as aluminum foil / copper foil, the relationship formula between Sx and S1 is: (0.5 - 0.8)S1 ≤ Sx ≤ S1; for ultrasonic welding of relatively hard foil materials such as stainless steel / titanium foil, the relationship formula between Sx and S1 is: (0.6 - 0.8)S1 ≤ Sx ≤ S1. It should be noted that the above size design relationship is an empirical value, and the specific implementation effect depends on the material selection strength / hardness, number of layers, and preset lifespan of the welding head and the foil material to be welded.

[0228] In the above technical solution, by determining whether the ratio of the welding area Sx of a single first weld mark 241 to the designed area S1 of the single first weld mark 241 is less than 0.2, the wear degree of the main welding teeth 20 can be determined, and thus whether the lifespan of the ultrasonic welding head 100 has reached its end can be determined, enabling a relatively simple and accurate judgment of whether the ultrasonic welding head 100 should be replaced or repaired.

[0229] In some embodiments, the wear condition of the ultrasonic welding head 100 is determined according to the ratio of the welding area of a single second weld mark 242 to the designed area of the single second weld mark 242, including: the welding area of the single second weld mark 242 is Sy, the designed area of the single second weld mark 242 is S2, and when the ratio of Sy to S2 is less than 0.2, it is determined that the lifespan of the ultrasonic welding head 100 has reached its end.

[0230] Among them, the designed area of the single second weld mark 242 refers to: when the ultrasonic welding head 100 is first tested, the welding area formed by the auxiliary welding teeth 30 on the workpiece sample, and this welding area can be obtained by using the above calculation method.

[0231] For example, when the ratio of Sy to S2 is 0.3, it is determined that the lifespan of the ultrasonic welding head 100 has not reached its end and it can continue to be used; when the ratio of Sy to S2 is 0.18, it is determined that the lifespan of the ultrasonic welding head 100 has reached its end and its continued use is stopped.

[0232] For example, if the lifespan of the ultrasonic welding head 100 has not been reached and it can still be used, the relationship between Sy and S2 can be designed according to the hardness of the foil material. For example, for welding softer foil materials such as aluminum foil / copper foil, the relationship between Sy and S2 is: (0.5 - 0.8)S2 ≤ Sy ≤ S2; for ultrasonic welding of harder foil materials such as stainless steel / titanium foil, the relationship between Sy and S2 is: (0.6 - 0.8)S2 ≤ Sy ≤ S2. It should be noted that the above size design relationship is an empirical value, and the specific implementation effect depends on the selected material strength / hardness, number of layers, and preset lifespan of the welding head and the foil material to be welded.

[0233] In the above technical solution, by judging whether the ratio of the welding area Sy of a single second weld mark 242 to the designed area S2 of the single second weld mark 242 is less than 0.2, the wear degree of the auxiliary welding teeth 30 can be judged, and thus whether the lifespan of the ultrasonic welding head 100 has reached can be judged, and it can be simply and accurately judged whether the ultrasonic welding head 100 should be replaced or repaired.

[0234] Fourth aspect, referring to Figure 10 and combining Figures 5 - 6 , the present invention provides a battery cell 200, including: a housing 21, the housing 21 is provided with electrode terminals 22; an electrode assembly 23, the electrode assembly 23 is arranged in the housing 21 and includes tab ears 231, the tab ears 231 are connected to the electrode terminals 22, the tab ears 231 include a plurality of tab ear pieces 231 stacked and welded together, a weld mark area 24 is formed on the tab ears 231, the weld mark area 24 includes a first weld mark 241 and a second weld mark 242, both the first weld mark 241 and the second weld mark 242 are formed as groove structures, the second weld mark 242 is located between adjacent first weld marks 241, and the groove depth of the second weld mark 242 is less than or equal to the groove depth of the first weld mark 241.

[0235] The housing 21 of the battery cell 200 is usually at least partially made of a metal material. For example, the housing 21 can be an aluminum case or a steel case.

[0236] For example, multiple tab ear pieces 231 can be welded by ultrasonic welding.

[0237] For example, the weld mark area 24 of the tab ear pieces 231 can be formed by welding a plurality of tab ear pieces 231 with the ultrasonic welding head 100 according to the first aspect embodiment of the present application. At this time, the weld mark area 24 can correspond to the welding surface 11, the first weld mark 241 can correspond to the main welding teeth 20, and the second weld mark 242 can correspond to the auxiliary welding teeth 30. That is, during the welding process, the main welding teeth 20 of the ultrasonic welding head 100 can form the first weld mark 241 on the tab ears 231, and the auxiliary welding teeth 30 of the ultrasonic welding head 100 can form the second weld mark 242 on the tab ears 231.

[0238] In the above technical solution, the first weld mark 241 and the second weld mark 242, both of which are groove structures, are formed by welding on multiple layers of tab 231 sheets. During the welding process of the multiple layers of tab 231 sheets, the first weld mark 241 and the second weld mark 242 can weld and connect the multiple layers of tab 231 sheets, and the second weld mark 242 is located between adjacent first weld marks 241 and the groove depth of the second weld mark 242 is less than or equal to the groove depth of the first weld mark 241. When using the ultrasonic welding head 100 to weld the multiple layers of tab 231 sheets, the first weld mark 241 can play a main welding and connecting role. By adding the second weld mark 242 between the first weld marks 241 and the groove depth of the second weld mark 242 is less than or equal to the groove depth of the first weld mark 241, the second weld mark 242 can perform local strengthening welding on the un-welded area between the layers of the multiple layers of tab 231 sheets, which can reduce the problem of local virtual welding of the tab 231 and the problem of insufficient over-current area of the tab 231 caused by the local virtual welding problem of the tab 231, and is beneficial to improving the service stability of the battery.

[0239] In some embodiments, referring to Figures 5 - 6 , the ratio range of the groove depth of the second weld mark 242 to the groove depth of the first weld mark 241 is 0.2 to 0.8.

[0240] For example, the ratio of the groove depth of the second weld mark 242 to the groove depth of the first weld mark 241 can be 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, etc.

[0241] In the above technical solution, by making the ratio of the groove depth of the second weld mark 242 to the groove depth of the first weld mark 241 not less than 0.2, the second weld mark 242 can perform effective local strengthening welding on the un-welded area between the layers of the multiple layers of tab 231 sheets, improving the local strengthening welding effect; by making the ratio of the groove depth of the second weld mark 242 to the groove depth of the first weld mark 241 not greater than 0.8, the influence of the second weld mark 242 on the first weld mark 241 can be reduced. While the first weld mark 241 plays a main welding role, the second weld mark 242 cooperates with the first weld mark 241 to perform effective local strengthening welding on the un-welded area between the first weld marks 241, which can better reduce the virtual welding problem and better improve the welding quality of the multiple layers of tab 231 sheets.

[0242] In some embodiments, referring to Figures 5 - 6 , the weld mark area of a single second weld mark 242 is smaller than the weld mark area of a single first weld mark 241.

[0243] Among them, the weld mark area of a single second weld mark 242 and the weld mark area of a single first weld mark 241 can be obtained by using the calculation method in the third aspect embodiment above.

[0244] In the above technical solution, by making the welding area of a single second weld mark 242 smaller than that of a single first weld mark 241, and the welding area of a single first weld mark 241 being larger, a single first weld mark 241 can play a better main welding role relative to a single second weld mark 242. The second weld mark 242 cooperates with the first weld mark 241 to effectively locally strengthen the welding of the un-welded area between the first weld marks 241, so that the cooperation effect between the second weld mark 242 and the first weld mark 241 can be better, the problem of false soldering can be better reduced, and the welding quality of the multi-layer tab 231 can be better improved.

[0245] In some embodiments, referring to Figures 5 - 6 , the ratio of the welding area of a single second weld mark 242 to the welding area of a single first weld mark 241 is 0.1 to 0.8.

[0246] For example, the ratio of the welding area of a single second weld mark 242 to the welding area of a single first weld mark 241 can be 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, etc.

[0247] In the above technical solution, by making the ratio of the welding area of a single second weld mark 242 to the welding area of a single first weld mark 241 not less than 0.1, the second weld mark 242 can effectively locally strengthen the welding of the un-welded area between the layers of the multi-layer tab 231, and the local strengthening area is large, which helps to improve the local strengthening welding effect; by making the ratio of the welding area of a single second weld mark 242 to the welding area of a single first weld mark 241 not more than 0.8, the influence of the second weld mark 242 on the first weld mark 241 can be reduced. While the first weld mark 241 plays a main welding role, the second weld mark 242 cooperates with the first weld mark 241 to effectively locally strengthen the welding of the un-welded area between the first weld marks 241, so that the problem of false soldering can be better reduced, and the welding quality of the multi-layer tab 231 can be better improved.

[0248] In some embodiments, referring to Figures 5 - 6 , the tab 231 is connected to the electrode terminal 22 through the adapter piece 25, and the multi-layer tab 231 is ultrasonically welded to the adapter piece 25.

[0249] For example, after the multi-layer tab 231 is ultrasonically welded to the adapter piece 25, the adapter piece 25 is then welded to the electrode terminal 22. For example, the adapter piece 25 and the electrode terminal 22 are laser welded.

[0250] In the above technical solution, the tab 231 is connected to the electrode terminal 22 through the adapter piece 25, which can facilitate the electrical connection between the tab 231 and the electrode terminal 22. Moreover, by ultrasonic welding the multi-layer tab 231 sheets to the adapter piece 25, the first weld mark 241 can play a major role in the welding connection, and the second weld mark 242 can perform local strengthening welding on the un-welded areas between the layers of the multi-layer tab 231 sheets. This can reduce the problem of local virtual soldering of the tab 231 and the problem of insufficient current-carrying area of the tab 231 caused by the local virtual soldering problem of the tab 231, improve the welding quality between the multi-layer tab 231 sheets and the adapter piece 25, and since the welding area of the tab 231 and the adapter piece 25 is increased, it can reduce the risk of local ablation of the battery electrode sheet caused by over-concentrated heat generation in the welding area of the tab 231 and the adapter piece 25 during the operation of the battery, which is beneficial to improving the service stability of the battery.

[0251] Fifthly, referring to Figure 11 , the present invention provides a battery device 300, including: a box body 50; a battery cell 200 according to the fourth aspect embodiment of the present invention above, and the battery cell 200 is arranged inside the box body 50.

[0252] In the above technical solution, by arranging the above battery cell 200, the first weld mark 241 and the second weld mark 242, both of which are groove structures, are formed by welding on the multi-layer tab 231 sheets of the tab 231. During the welding process of the multi-layer tab 231 sheets, the first weld mark 241 and the second weld mark 242 can weld and connect the multi-layer tab 231 sheets, and the second weld mark 242 is located between adjacent first weld marks 241 and the groove depth of the second weld mark 242 is less than or equal to the groove depth of the first weld mark 241. When using the ultrasonic welding head 100 to weld the multi-layer tab 231 sheets, the first weld mark 241 can play a major role in the welding connection. By adding the second weld mark 242 between the first weld marks 241 and the groove depth of the second weld mark 242 is less than or equal to the groove depth of the first weld mark 241, the second weld mark 242 can perform local strengthening welding on the un-welded areas between the layers of the multi-layer tab 231 sheets, which can reduce the problem of local virtual soldering of the tab 231 and the problem of insufficient current-carrying area of the tab 231 caused by the local virtual soldering problem of the tab 231, and is beneficial to improving the service stability of the battery.

[0253] Sixthly, referring to Figure 12 , the present invention provides an electrical device 400, including the battery device 300 according to the fifth aspect embodiment of the present invention above.

[0254] Among them, the electrical device 400 can be a vehicle, and the battery device 300 can be installed at the bottom of the vehicle body 60.

[0255] In the above technical solution, by providing the above-mentioned electrical device 400, the battery cells 200 of the electrical device 400 are welded on the multi-layer tab 231 sheets of the tab 231 to form a first weld mark 241 and a second weld mark 242 both having a groove structure. During the welding process of the multi-layer tab 231 sheets, the first weld mark 241 and the second weld mark 242 can weld and connect the multi-layer tab 231 sheets, and the second weld mark 242 is located between adjacent first weld marks 241 and the groove depth of the second weld mark 242 is less than or equal to the groove depth of the first weld mark 241. When using the ultrasonic welding head 100 to weld the multi-layer tab 231 sheets, the first weld mark 241 can play a main role in welding and connecting. By adding the second weld mark 242 between the first weld marks 241 and the groove depth of the second weld mark 242 is less than or equal to the groove depth of the first weld mark 241, the second weld mark 242 can perform local strengthening welding on the un-welded areas between the layers of the multi-layer tab 231 sheets, which can reduce the problem of local virtual welding of the tab 231 and the problem of insufficient over-current area of the tab 231 caused by the local virtual welding problem of the tab 231, and is beneficial to improving the service stability of the battery.

[0256] The following refers to Figures 1 - 8 Describe the ultrasonic welding head 100 according to some embodiments of the present invention.

[0257] In this embodiment, the ultrasonic welding head 100 includes a welding head body 10, main welding teeth 20, and auxiliary welding teeth 30. The welding head body 10 has a welding surface 11. The main welding teeth 20 protrude from the welding surface 11 and are a plurality of spaced-apart. In the protruding direction of the welding teeth relative to the welding surface 11, the tooth height of the main welding teeth 20 is h1. The auxiliary welding teeth 30 protrude from the welding surface 11 and the auxiliary welding teeth 30 are located between adjacent main welding teeth 20. In the protruding direction of the welding teeth relative to the welding surface 11, the tooth height of the auxiliary welding teeth 30 is h2; wherein, the ratio of h2 to h1 is less than 1. The projection of a single main welding tooth 20 on the welding surface 11 is a first projection, the projection of a single auxiliary welding tooth 30 on the welding surface 11 is a second projection, the second projection and the first projection are spaced apart, and the ratio of the area of the second projection to the area of the first projection is less than 1. The projection of the end surface of a single welding tooth on the welding surface 11 is a third projection, and the ratio of the area of the second projection to the area of the third projection is less than 1. The minimum distance between the second projection and the first projection is d, the equivalent diameter of the second projection is D0, and the ratio of d to D0 is less than 0.35.

[0258] A plurality of main welding teeth 20 are arranged in multiple rows and columns. The multiple columns of main welding teeth 20 are arranged along a first direction, and the multiple rows of main welding teeth 20 are arranged along a second direction. The first direction intersects the second direction, and the number of columns of the main welding teeth 20 is greater than the number of rows of the main welding teeth 20. A first channel 14 is formed between two adjacent columns of main welding teeth 20, and a second channel 15 is formed between two adjacent rows of main welding teeth 20. The first channel 14 intersects the second channel 15. An auxiliary welding tooth 30 is provided at the intersection of the first channel 14 and the second channel 15. The main welding tooth 20 is in the shape of a frustum of a pyramid, and the auxiliary welding tooth 30 is spherical.

[0259] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples", etc. means 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 may be combined in any one or more embodiments or examples in a suitable manner.

[0260] 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 welding head body having a welding surface; Main welding teeth protruding from the welding surface and arranged at intervals. In the protruding direction of the teeth relative to the welding surface, the tooth height of the main welding teeth is h1; Auxiliary welding teeth protruding from the welding surface and located between adjacent main welding teeth. In the protruding direction of the teeth relative to the welding surface, the tooth height of the auxiliary welding teeth is h2; Wherein, the ratio range of h2 to h1 is 0.2 - 0.

8.

2. The ultrasonic welding head according to claim 1, wherein The projection of a single main welding tooth on the welding surface is the first projection, and the projection of a single auxiliary welding tooth on the welding surface is the second projection. The area ratio of the second projection to the first projection is less than 1.

3. The ultrasonic welding head according to claim 2, wherein The area ratio of the second projection to the first projection is 0.1 - 0.

8.

4. The ultrasonic welding head according to claim 1, characterized in that, The projection of a single auxiliary welding tooth on the welding surface is the second projection. The surface on the side of the main welding tooth away from the welding surface constitutes the tooth end surface. The projection of a single tooth end surface on the welding surface is the third projection. The area ratio of the second projection to the third projection is less than 1.

5. The ultrasonic welding head according to claim 4, characterized in that, The area ratio of the second projection to the third projection is 0.3 - 0.

8.

6. The ultrasonic welding head according to claim 1, wherein, The projection of a single main welding tooth on the welding surface is the first projection, and the projection of a single auxiliary welding tooth on the welding surface is the second projection. The second projection and the first projection are arranged at intervals.

7. The ultrasonic welding head according to claim 6, wherein, The minimum distance between the second projection and the first projection is d, and the equivalent diameter of the second projection is D0. The ratio of d to D0 is less than 0.

35.

8. The ultrasonic welding head according to claim 7, wherein, The ratio range of d to D0 is 0.1 - 0.

25.

9. The ultrasonic welding head according to claim 1, wherein, A plurality of the main welding teeth are arranged in multiple rows and multiple columns. The multiple columns of main welding teeth are arranged along a first direction, and the multiple rows of main welding teeth are arranged along a second direction. The first direction intersects with the second direction. A first channel is formed between adjacent two columns of main welding teeth, and a second channel is formed between adjacent two rows of main welding teeth. The first channel intersects with the second channel. The first channel and / or the second channel are provided with the auxiliary welding teeth.

10. The ultrasonic welding head according to claim 9, characterized in that, The projection of a single auxiliary welding tooth on the welding surface is the second projection. The projection of a single first channel on the welding surface is the fourth projection. The projection of a single second channel on the welding surface is the fifth projection. The maximum dimension of the second projection in the first direction is D1, the maximum dimension of the second projection in the second direction is D2, the width dimension of the fourth projection in the first direction is W1, and the width dimension of the fifth projection in the second direction is W2; Wherein, the ratio of D1 to W1 is greater than 0.8 and / or the ratio of D2 to W2 is greater than 0.

8.

11. The ultrasonic welding head according to claim 9, characterized in that, The auxiliary welding teeth are arranged at the intersection of the first channel and the second channel.

12. The ultrasonic welding head according to claim 11, characterized in that, The projection of a single auxiliary welding tooth on the welding surface is a second projection, the projection of a single first channel on the welding surface is a fourth projection, and the projection of a single second channel on the welding surface is a fifth projection. The maximum dimension of the second projection in the first direction is D1, the maximum dimension of the second projection in the second direction is D2, the width dimension of the fourth projection in the first direction is W1, and the width dimension of the fifth projection in the second direction is W2. The ratio of W1 to W2 is greater than 1; Among them, the auxiliary welding tooth provided at the intersection of the first channel and the second channel satisfies that the ratio of D2 to W2 is greater than 1.

13. The ultrasonic welding head according to claim 12, characterized in that, The auxiliary welding tooth provided at the intersection of the first channel and the second channel satisfies that the ratio range of D2 to W2 is 1.5 to 3.

14. The ultrasonic welding head according to claim 12, wherein, The auxiliary welding tooth provided at the intersection of the first channel and the second channel satisfies that the ratio of D1 to W1 is less than 1.

15. The ultrasonic welding head according to claim 12, wherein, The number of columns of the main welding teeth is greater than the number of rows of the main welding teeth.

16. The ultrasonic welding head according to claim 11, wherein, There are multiple auxiliary welding teeth, and the multiple auxiliary welding teeth include a first auxiliary welding tooth provided at the intersection of the first channel and the second channel. The multiple auxiliary welding teeth further include at least one of a second auxiliary welding tooth and a third auxiliary welding tooth. The second auxiliary welding tooth is provided in the first channel and is offset from the intersection position of the first channel and the second channel, and the third auxiliary welding tooth is provided in the second channel and is offset from the intersection position of the first channel and the second channel; Among them, in the protruding direction of the welding teeth relative to the welding surface, the tooth heights of the second auxiliary welding tooth and the third auxiliary welding tooth are both less than the tooth height of the first auxiliary welding tooth; and / or, the projected area of a single second auxiliary welding tooth and a single third auxiliary welding tooth on the welding surface is both less than the projected area of a single first auxiliary welding tooth on the welding surface.

17. The ultrasonic welding head according to any one of claims 1-16, characterized in that, In the protruding direction of the welding teeth relative to the welding surface, the cross-sectional area of the main welding teeth gradually decreases and / or the cross-sectional area of the auxiliary welding teeth gradually decreases.

18. The ultrasonic welding head according to any one of claims 1-16, characterized in that, The main welding teeth are frustum-shaped or spherical; and / or, the auxiliary welding teeth are spherical.

19. The ultrasonic welding head according to any one of claims 1-16, characterized in that, An avoidance surface is formed on the welding head body. The avoidance surface is located on the outer peripheral side of the welding surface and is connected to the welding surface. The angle between the avoidance surface and the welding surface is an obtuse angle, and the avoidance surface and the welding surface are smoothly transitioned through an arc surface. A shaping welding tooth is provided at the connection between the avoidance surface and the welding surface.

20. An ultrasonic welding device, characterized in that, Including: The ultrasonic welding head according to any one of claims 1-19.

21. 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 1-19. The wear detection method of the ultrasonic welding head includes: Using the ultrasonic welding head to perform ultrasonic pre-welding on a workpiece sample. The weld mark corresponding to the main welding tooth on the workpiece sample is the first weld mark, and the weld mark corresponding to the auxiliary welding tooth on the workpiece sample is the second weld mark; Identifying the first weld mark and / or the second weld mark formed on the workpiece sample; Calculating the weld mark area of a single first weld mark and / or calculating the weld mark area of a single second weld mark; Judge the wear condition of the ultrasonic welding head according to the welding mark area of a single said first welding mark and / or the welding mark area of a single said second welding mark.

22. The wear detection method of the ultrasonic welding head according to claim 21, wherein, Identify the said first welding mark and / or the said second welding mark formed on the workpiece sample, including: Collect the welding mark image of the side of the workpiece sample where the welding mark is formed; Identify the said first welding mark and / or the said second welding mark in the welding mark image.

23. The method for detecting wear of an ultrasonic welding head according to claim 21, wherein Calculate the welding mark area of a single said first welding mark and / or calculate the welding mark area of a single said second welding mark, including: Identify the outer contour of a single said first welding mark and / or identify the outer contour of a single said second welding mark; Calculate the area of the figure enclosed by the outer contour of the first welding mark and / or calculate the area of the figure enclosed by the outer contour of the second welding mark.

24. The method for detecting wear of an ultrasonic welding head according to claim 21, wherein, Judge the wear condition of the ultrasonic welding head according to the welding mark area of a single said first welding mark and / or the welding mark area of a single said second welding mark, including: Judge the wear condition of the ultrasonic welding head according to the ratio of the welding mark area of a single said first welding mark to the designed area of a single said first welding mark; And / or, judge the wear condition of the ultrasonic welding head according to the ratio of the welding mark area of a single said second welding mark to the designed area of a single said second welding mark.

25. The wear detection method of the ultrasonic welding head according to claim 24, characterized in that, Judge the wear condition of the ultrasonic welding head according to the ratio of the welding mark area of a single said first welding mark to the designed area of a single said first welding mark, including: The welding mark area of a single said first welding mark is Sx, and the designed area of a single said first welding mark is S1. When the ratio of Sx to S1 is less than 0.2, judge that the service life of the ultrasonic welding head has reached.

26. The method for detecting the wear of an ultrasonic welding head according to claim 24, characterized in that, Judge the wear condition of the ultrasonic welding head according to the ratio of the welding mark area of a single said second welding mark to the designed area of a single said second welding mark, including: The welding mark area of a single said second welding mark is Sy, and the designed area of a single said second welding mark is S2. When the ratio of Sy to S2 is less than 0.2, judge that the service life of the ultrasonic welding head has reached.

27. A battery cell, characterized in that, Include: A housing, and the housing is provided with electrode terminals; An electrode assembly, the electrode assembly is arranged in the housing and includes a tab, the tab is connected to the electrode terminal, the tab includes a plurality of tab pieces arranged in a stacked manner and connected by welding, a welding mark area is formed on the tab, 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, the second welding mark is located between adjacent said first welding marks, and the ratio range of the groove depth of the second welding mark to the groove depth of the first welding mark is 0.2-0.

8.

28. The battery cell according to claim 27, characterized in that, The welding mark area of a single said second welding mark is smaller than the welding mark area of a single said first welding mark.

29. The battery cell according to claim 28, wherein The ratio of the welding mark area of a single said second welding mark to the welding mark area of a single said first welding mark is 0.1-0.

8.

30. The battery cell according to any one of claims 27-29, characterized in that The tab is connected to the electrode terminal through an adapter plate, and multiple layers of the tab pieces are ultrasonically welded to the adapter plate.

31. A battery device, characterized in that, Include: A box body; The battery cell according to any one of claims 27-30 is arranged in the box body.

32. An electrical device, characterized in that, Include the battery device according to claim 31.

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