Battery and method of manufacturing a battery

Abstract

The application relates to the technical field of batteries, and discloses a battery and a battery manufacturing method. The battery comprises a battery core, the battery core comprises a battery core body and a tab, the tab extends out of the battery core body, the tab comprises a first welding mark and a second welding mark, the second welding mark covers the first welding mark, and the second welding mark forms a circumferentially closed space to expose the first welding mark. That is, the tab is welded twice when the tab and a cover plate assembly are welded, and a hollow second welding mark is formed, welding energy can be better controlled, heat dissipation can be better realized, welding heat is not concentrated, heat distribution is more uniform, the welding quality is improved, and the service performance of the battery is improved.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and more particularly to a battery and a method for manufacturing the battery. Background Technology

[0002] In related technologies, the cover plate assembly is connected to the electrode tab of the battery cell. The connection between the electrode tab and the cover plate assembly is achieved directly by welding. Due to the limitations of the electrode tab's own structure, damage to the electrode tab or poor welding quality may occur during welding, thus affecting the reliability of the connection. Summary of the Invention

[0003] This invention provides a battery and a method for manufacturing the battery to improve battery performance.

[0004] According to a first aspect of the present invention, a battery is provided, comprising a cell, the cell including a cell body and a tab, the tab extending from the cell body, the tab including a first solder mark and a second solder mark, the second solder mark covering the first solder mark, and the second solder mark forming a circumferentially closed space to expose the first solder mark.

[0005] The battery of this invention includes a cell, which includes a cell body and a tab extending from the cell body. A first solder mark and a second solder mark are formed on the tab, with the second solder mark covering the first solder mark and forming a circumferentially enclosed space to expose a portion of the first solder mark. That is, when welding the tab to the cover plate assembly, the tab is welded twice, and a hollow second solder mark is formed. This allows for better control of welding energy and better heat dissipation, resulting in less concentrated welding heat and a more uniform heat distribution, thereby improving welding quality and thus improving the battery's performance.

[0006] According to a second aspect of the present invention, a method for manufacturing a battery is provided, comprising:

[0007] Multiple single-piece tabs on the main body of the battery cell are pre-welded to form the first solder mark on the tabs;

[0008] The electrode post assembly and the electrode tab of the cover plate assembly are welded to form a second solder mark on the electrode tab, such that the second solder mark covers the first solder mark, and the second solder mark forms a circumferentially closed space to expose the first solder mark; or,

[0009] The adapter piece of the cover plate assembly is welded to the electrode tab to form a second solder mark on the electrode tab, such that the second solder mark covers the first solder mark, and the second solder mark forms a circumferentially closed space to expose the first solder mark.

[0010] The battery manufacturing method of this invention pre-welds the tabs to form a first weld mark, and then welds the cover plate assembly and the tabs on the first weld mark to form a second weld mark. That is, the tabs are welded twice, and the second weld mark forms a circumferentially closed space, thereby exposing a part of the first weld mark, thus forming a hollow second weld mark. This allows for better control of welding energy and better heat dissipation, resulting in less concentrated welding heat and a more uniform heat distribution, thereby improving welding quality. Attached Figure Description

[0011] To better understand this disclosure, reference may be made to the embodiments shown in the following figures. Components in the figures are not necessarily to scale, and related elements may be omitted to emphasize and clearly illustrate the technical features of this disclosure. Additionally, related elements or components may have different arrangements as known in the art. Furthermore, in the figures, the same reference numerals denote the same or similar components in various figures. Wherein:

[0012] Figure 1 This is a schematic diagram of the structure of a battery tab according to an exemplary embodiment;

[0013] Figure 2 This is a partial structural schematic diagram of a battery according to an exemplary embodiment;

[0014] Figure 3 This is a partial structural schematic diagram of a battery according to an exemplary embodiment;

[0015] Figure 4 This is a partial structural schematic diagram of a battery according to another exemplary embodiment;

[0016] Figure 5 This is a partial structural schematic diagram of a battery pack according to an exemplary embodiment;

[0017] Figure 6 This is a schematic flowchart illustrating a battery manufacturing method according to an exemplary embodiment.

[0018] The annotations in the attached figures are explained as follows:

[0019] 1. Battery housing; 2. Battery module; 10. Battery cell; 11. Battery cell body; 12. Terminal tab; 121. First weld mark; 122. Second weld mark; 123. Space; 20. Cover plate; 30. Terminal post assembly; 40. Adapter piece; 41. Fusible link; 50. Housing component. Detailed Implementation

[0020] The technical solutions in the exemplary embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. The exemplary embodiments described herein are for illustrative purposes only and are not intended to limit the scope of protection of this disclosure. Therefore, it should be understood that various modifications and changes can be made to the exemplary embodiments without departing from the scope of protection of this disclosure.

[0021] In the description of this disclosure, unless otherwise expressly specified and limited, the terms “first” and “second” are used for descriptive purposes only and should not be construed as indicating or implying relative importance; the term “multiple” refers to two or more; and the term “and / or” includes any and all combinations of one or more associated listed items. In particular, references to “the / described” object or “a” object are also intended to indicate one of a possible plurality of such objects.

[0022] Unless otherwise specified or stated, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, an integral connection, an electrical connection, or a signal connection; "connection" can be a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this disclosure according to the specific circumstances.

[0023] Furthermore, it should be understood that the directional terms such as "upper," "lower," "inner," and "outer" described in the exemplary embodiments of this disclosure are used to describe the angles shown in the accompanying drawings and should not be construed as limiting the exemplary embodiments of this disclosure. It should also be understood that, in the context of a reference to an element or feature being connected to another element(s) "upper," "lower," "inner," or "outer," it can be directly connected to the other element(s) "upper," "lower," "inner," or "outer," or indirectly connected to the other element(s) "upper," "lower," "inner," or "outer" through an intermediate element.

[0024] One embodiment of the present invention provides a battery, please refer to... Figures 1 to 4 The battery includes a cell 10, which includes a cell body 11 and a tab 12. The tab 12 extends from the cell body 11 and includes a first solder mark 121 and a second solder mark 122. The second solder mark 122 covers the first solder mark 121 and forms a circumferentially closed space 123 to expose the first solder mark 121.

[0025] A battery according to one embodiment of the present invention includes a cell 10, the cell 10 including a cell body 11 and a tab 12 extending from the cell body 11. By forming a first solder mark 121 and a second solder mark 122 on the tab 12, the second solder mark 122 covers the first solder mark 121 and forms a circumferentially closed space 123 in the second solder mark 122, thereby exposing a part of the first solder mark 121. That is, when welding the tab 12 to the cover plate assembly, the tab 12 is welded twice and a hollow second solder mark 122 is formed. This can better control the welding energy, better achieve heat dissipation, make the welding heat less concentrated, and make the heat distribution more uniform, thereby improving the welding quality and thus improving the performance of the battery.

[0026] It should be noted that the second weld mark 122 covers the first weld mark 121. That is, after the first weld mark 121 is formed by the first weld, the second weld is still performed within the area of ​​the first weld mark 121, thus forming the second weld mark 122 on the first weld mark 121. Furthermore, since the second weld mark 122 forms a circumferentially enclosed space 123, i.e., the second weld mark 122 is a hollow weld mark, heat dissipation is better achieved, resulting in less concentrated welding heat and a more uniform heat distribution, thereby improving welding quality and appearance. The second weld mark 122 covering the first weld mark 121 can be considered as the orthographic projection of the second weld mark 122 being located within the first weld mark 121, while the space 123 can expose the first weld mark 121. Of course, the outer circumferential side of the second weld mark 122 can also expose the first weld mark 121. In some embodiments, it is not excluded that the outer circumferential side of the second weld mark 122 does not expose the first weld mark 121.

[0027] The second solder mark 122 is a hollow solder mark, and the space 123 of the hollow solder mark can serve as a heat dissipation space. Moreover, the weld width is relatively smaller than that of the solid solder mark, which is conducive to uniform temperature distribution and thus makes it less likely to cause delamination and unevenness of the solder mark surface. In this way, a high-quality solder mark can be obtained through the hollow solder mark.

[0028] In one embodiment, space 123 is circular, that is, the middle part of the second solder mark 122 forms a circle, which not only facilitates the design of the welding trajectory of the welding head to form the second solder mark 122, but also ensures the welding quality of the tab 12 and the cover plate assembly, and ensures that the second solder mark 122 covers the area of ​​the first solder mark 121, thereby ensuring the welding stability of the tab 12 and the cover plate assembly.

[0029] In one embodiment, the second weld mark 122 is an annular ring, thereby forming a circular space 123. The annular second weld mark 122 is easier to form during the forming process because the corners are rounded. Furthermore, the welding trajectory for forming the second weld mark 122 is relatively simple. This improves welding efficiency while enhancing the welding stability between the tab 12 and the cover plate assembly.

[0030] In one embodiment, the area of ​​space 123 accounts for 5%-30% of the sum of the area of ​​the second solder mark 122 and the area of ​​space 123. This ensures that the space 123 of the hollow solder mark can serve as a heat dissipation space, while also ensuring that the second solder mark 122 has sufficient area, thereby guaranteeing the reliability of the soldering.

[0031] When the area of ​​space 123 occupies less than 5% of the sum of the areas of the second solder mark 122 and space 123, it is not conducive to heat dissipation and may cause heat concentration. When the area of ​​space 123 occupies more than 30% of the sum of the areas of the second solder mark 122 and space 123, the area of ​​the second solder mark 122 is not large enough, which will cause poor connection stability and affect the stability of the battery. In addition, insufficient welding area leads to insufficient overcurrent capacity of the overcurrent battery, affecting battery performance.

[0032] The area of ​​space 123 can be a, the area of ​​the second solder mark 122 can be b, and a / (a+b) can be 5%, 6%, 7%, 8%, 10%, 12%, 15%, 16%, 20%, 22%, 23%, 25%, 26%, 27%, 29%, or 30%, etc.

[0033] In one embodiment, the area of ​​the second solder mark 122 is 10 mm². 2 -200 mm 2 This ensures that the area of ​​the second weld mark 122 is relatively reasonable, and without taking up too much area, thus affecting welding efficiency, while ensuring connection stability.

[0034] The area of ​​the second solder mark 122 can be 10mm². 2 11mm 2 15mm 2 20mm 2 30mm 2 40mm 2 50mm 2 55mm 2 60mm 2 70mm 2 75mm 2 80mm 2 90mm 2 100mm 2 120mm 2 150mm 2 155mm 2 165mm 2 170mm 2 175mm 2 180mm2 185mm 2 190mm 2 195mm 2 199mm 2 Or 200mm 2 etc.

[0035] In one embodiment, the weld width of the second solder mark 122 is 1.5mm-6mm, thereby ensuring that the second solder mark 122 can reliably connect to the tab 12 and preventing the second solder mark 122 from being too wide.

[0036] The second weld mark 122 can be a ring, and the weld width of the second weld mark 122 is the ring diameter. The weld width of the second weld mark 122 can be 1.5mm, 1.6mm, 1.7mm, 2mm, 2.5mm, 2.8mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, 5.5mm, 5.8mm, 5.9mm, or 6mm, etc.

[0037] It should be noted that the weld width of the second solder mark 122 can be considered as the weld width of the tab 12 when the second solder mark 122 is formed. Furthermore, in combination with... Figure 1 As shown, the second solder mark 122 is a ring, and the weld width of the second solder mark 122 is the ring diameter, which is the difference between the outer diameter and the inner diameter of the ring.

[0038] In one embodiment, the first solder mark 121 is rectangular, which not only has a simple structure and is easy to form, but also ensures that the tab 12 has reliable connection quality.

[0039] In one implementation, the first solder mark 121 is square, and the size of the first solder mark 121 is 5mm×5mm-20mm×20mm. While facilitating welding and forming, it can avoid the first solder mark 121 being too large, which would cause damage to the tab 12 and would not be conducive to improving welding efficiency. Furthermore, it can avoid the first solder mark 121 being too small, which would not guarantee the connection stability of the tab 12.

[0040] The dimensions of the first solder mark 121 are 5mm×5mm-20mm×20mm, that is, the length dimension of the first solder mark 121 is equal to the width dimension. The dimensions of the first solder mark 121 can be 5mm×5mm, 6mm×6mm, 7mm×7mm, 10mm×10mm, 15mm×15mm, 16mm×16mm, 17mm×17mm, 19mm×19mm or 20mm×20mm, etc.

[0041] In one embodiment, the second solder marks 122 are all located within the first solder marks 121, thus minimizing damage to the tab 12. It should be noted that since the second solder marks 122 are all located within the first solder marks 121, after the first solder marks 121 are formed, a second soldering is required. It is necessary to ensure that the soldering area aligned for the second soldering is within the first solder marks 121. This mainly refers to the soldering area of ​​the tab 12, not the soldering area of ​​the cover plate assembly. That is, using the tab 12 as a soldering reference, the second solder marks 122 can be formed during the soldering of the tab 12 and the cover plate assembly.

[0042] In one embodiment, the second solder mark 122 is located in the middle of the first solder mark 121, thereby ensuring that the tab 12 will not be damaged during the second welding and ensuring the welding stability of the tab 12 and the cover plate assembly.

[0043] It should be noted that "middle" does not specifically refer to the center position, but rather to the outer circumferential edge of the first solder mark 121. That is, if the second solder mark 122 does not intersect with the outer circumferential edge of the first solder mark 121, then the second solder mark 122 is located in the middle of the first solder mark 121.

[0044] In one embodiment, the second solder mark 122 is located at the center of the first solder mark 121.

[0045] In one embodiment, the first solder mark 121 can be a polygon, such as a rectangle. The first solder mark 121 can also be a circle, an ellipse, or an irregular shape, etc.

[0046] In one embodiment, the first solder mark 121 occupies at least a portion of the tab 12. The first solder mark 121 is formed by pre-welding the tab 12, that is, the tab 12 is pre-treated by welding before the tab 12 is connected to the cover plate assembly, so that the multiple single tabs forming the tab 12 are reliably connected.

[0047] In one embodiment, the tab 12 includes multiple individual tabs. A first solder mark 121 is formed by pre-welding the tab 12 to combine the multiple individual tabs. The first solder mark 121 can be formed by directly pre-welding the tab 12, that is, pre-welding the tab 12 before welding it to the cover plate assembly, thereby combining two or more individual tabs of the tab 12 together, which also improves the structural strength of the tab 12 to a certain extent. That is, all the individual tabs in the tab 12 are combined together, thus increasing the strength of the tab 12. The strength is relatively high, so when welding the tab 12 to the cover plate assembly, even if the welding energy is relatively large, the presence of the first weld mark 121 and the second weld mark 122 on the basis of the first weld mark 121 greatly reduce the probability of damage to the tab 12 during the second welding. Furthermore, considering that the second weld mark 122 is a hollow weld mark, although the energy concentration in the welding process is high, the presence of the first weld mark 121 will also greatly reduce the probability of damage to the tab 12.

[0048] The single electrode tab can be a metal sheet, which can be a thin metal sheet. The thin metal sheet can be part of the current collector, or other options are also possible, without specific limitations here.

[0049] In one embodiment, the tab 12 includes multiple individual tabs, the number of which is 100-200. That is, the tab 12 can be composed of a relatively large number of individual tabs. In order to improve the energy density of the battery, the cell 10 is made thicker, which results in more layers of individual tabs. In order to make the welding strength of the large number of individual tabs and the cover plate assembly, a high welding energy is usually required. However, if the heat is too concentrated, it will lead to poor welding quality. Therefore, by forming a first solder mark 121 and a second solder mark 122 on the tab 12, the welding reliability of the tab 12 can be guaranteed and the welding quality can be improved.

[0050] The number of individual electrodes that the tab 12 may include is 100, 101, 110, 115, 120, 125, 130, 140, 145, 150, 155, 160, 170, 180, 185, 190, 195, 199, or 200, etc.

[0051] In one embodiment, the first solder mark 121 and the second solder mark 122 are formed sequentially. That is, during the formation of the second solder mark 122, since it is carried out within the first solder mark 121, even if the welding energy is relatively large, the first solder mark 121 enhances the strength of the tab 12, thus avoiding damage to the tab 12.

[0052] In one embodiment, the first solder mark 121 and the second solder mark 122 are both laser solder marks; or, the first solder mark 121 and the second solder mark 122 are both ultrasonic solder marks.

[0053] In one embodiment, the first solder mark 121 and the second solder mark 122 are formed using different welding methods. The electrode tab includes a single electrode tab, which can be a thin metal sheet. The metal sheet is relatively thin. Welding method one is used to pre-weld the metal sheet, forming a stable connection between adjacent metal sheets, enhancing the strength of the electrode tab 12 and preventing damage to it. Then, welding method two is used to weld the electrode tab 12 and the cover plate assembly, enhancing the connection strength between the electrode tab 12 and the cover plate assembly while also preventing damage to the electrode tab 12. Different welding methods can involve different types of welding energy, or the same type of welding energy but different intensities.

[0054] The first weld mark 121 is an ultrasonic weld mark, and the second weld mark 122 is a laser weld mark; or, the first weld mark 121 is a laser weld mark, and the second weld mark 122 is an ultrasonic weld mark.

[0055] Specifically, the first welding creates a first weld mark 121, and the second welding creates a second weld mark 122. The first welding can be performed using either ultrasonic welding or laser welding. Similarly, the second welding can be performed using either ultrasonic welding or laser welding, as long as the stability of the connection is guaranteed and the tab 12 is not damaged during the first welding.

[0056] In one embodiment, the first weld mark 121 is an ultrasonic weld mark, and the second weld mark 122 is a laser weld mark. The first weld forms the first weld mark 121, and the second weld forms the second weld mark 122. The first weld uses ultrasonic welding, where multiple metal sheets of the tab 12 are bonded together as a whole through ultrasonic action. This can be considered as multiple metal sheets forming a single, thicker metal plate, enhancing the strength of the tab 12 and preventing damage to the tab. Correspondingly, the second weld uses laser welding, forming the second weld mark 122 on the first weld mark 121. This welds the cover plate assembly and the metal plate formed in the first weld. The laser action fixes the metal plate and cover plate assembly together, enhancing the connection strength. Furthermore, the space 123 formed in the second weld mark 122 allows for more concentrated laser energy, thereby improving the welding quality of the metal plate and cover plate assembly.

[0057] In one embodiment, there may be at least two first solder marks 121, with adjacent first solder marks 121 spaced apart. That is, during pre-welding, at least two first solder marks 121 are formed by separate welding. There may be one or at least two second solder marks 122. The second solder marks 122 may correspond one-to-one with the first solder marks 121, or there may be fewer second solder marks 122 than the first solder marks 121, that is, the second solder marks 122 are not covered on part of the first solder marks 121.

[0058] In one embodiment, the battery further includes a cover assembly, and a second solder mark 122 is formed by welding the tab 12 and the cover assembly to connect the tab 12 and the cover assembly, thereby making the cover assembly serve as an electrode lead-out terminal of the cell 10, and the hollow second solder mark 122 can improve the connection quality between the tab 12 and the cover assembly.

[0059] The cover plate assembly may include a cover plate 20 and a pole assembly 30, wherein the pole assembly 30 is disposed on the cover plate 20, and the tab 12 may be electrically connected to the pole assembly 30. Alternatively, the cover plate assembly may include a cover plate 20, wherein the tab 12 may be electrically connected to the cover plate 20.

[0060] In one embodiment, such as Figure 2 and Figure 3 As shown, the cover plate assembly includes a cover plate 20 and a pole post assembly 30. The pole post assembly 30 is disposed on the cover plate 20. The second weld mark 122 is formed by welding the tab 12 and the pole post assembly 30 to connect the tab 12 and the pole post assembly 30. Due to the presence of the first weld mark 121, the subsequently formed second weld mark 122 can not only avoid damage to the tab 12, but also ensure the connection stability of the tab 12 and the pole post assembly 30, thereby improving the welding quality of the tab 12 and the pole post assembly 30.

[0061] The pole assembly 30 can be directly welded to the tab 12, eliminating the need for the adapter piece in related technologies, reducing material costs and simplifying the process.

[0062] In one embodiment, such as Figure 2 and Figure 4 As shown, the cover plate assembly includes a cover plate 20, a pole assembly 30, and an adapter plate 40. The pole assembly 30 is disposed on the cover plate 20, and the adapter plate 40 is connected to the pole assembly 30. The second solder mark 122 is formed by welding the tab 12 and the adapter plate 40 to connect the tab 12 and the adapter plate 40. The tab 12 is electrically connected to the pole assembly 30 through the adapter plate 40, which not only facilitates the position arrangement of the pole assembly 30, but also facilitates the connection of the adapter plate 40 to the tab 12 and the pole assembly 30.

[0063] The first part of the adapter piece 40 is connected to the terminal assembly 30, while the second part of the adapter piece 40 is connected to the tab 12. At this time, the first and second parts do not need to overlap. Therefore, the first part of the adapter piece 40 can be welded or riveted to the terminal assembly 30, while the second part of the adapter piece 40 is welded to the tab 12, forming a second solder mark 122. The adapter piece 40 can be welded to both the terminal assembly 30 and the tab 12 simultaneously; that is, when the adapter piece 40 is welded to both the terminal assembly 30 and the tab 12 simultaneously, a second solder mark 122 can be formed.

[0064] In one embodiment, such as Figure 4 As shown, the adapter piece 40 includes a fuse part 41, so that after the current reaches a certain value, the adapter piece 40 can be disconnected at the position of the fuse part 41, thereby breaking the electrical connection between the tab 12 and the adapter piece 40. The fuse part 41 may be a through hole.

[0065] The adapter piece 40 includes a fused portion 41. Therefore, the space for connecting the tab 12 and the terminal assembly 30 in the adapter piece 40 is reduced. The welding area between the adapter piece 40 and the tab 12 determines the current carrying capacity of the battery. In this embodiment, by forming the first solder mark 121 and the second solder mark 122 in sequence, and the second solder mark 122 is formed on the first solder mark 121, the hollow second solder mark 122 can better control the welding energy and better achieve heat dissipation, so that the welding heat is not concentrated and the heat distribution is more uniform. Therefore, it can be ensured that the adapter piece 40 and the tab 12 can have a reliable welding area, thereby forming a stable connection in a limited space, thus ensuring the current carrying capacity of the battery.

[0066] The battery includes a cell 10 and an electrolyte, and is the smallest unit capable of electrochemical reactions such as charging / discharging. The cell 10 refers to a unit formed by winding or laminating stacked portions, which include a first electrode, a separator, and a second electrode. When the first electrode is a positive electrode, the second electrode is a negative electrode. The polarities of the first and second electrodes can be interchanged. The battery also includes a housing 20, to which a cover assembly is connected to achieve a reliable seal of the cell 10. There can be two cover assemblies, each disposed at opposite ends of the housing 20, and two terminal post assemblies 30 can be disposed on two separate cover 20s. In some embodiments, there can be a single cover assembly disposed on the housing 20, and both terminal post assemblies 30 can be simultaneously disposed on a single cover 20.

[0067] The battery cell 10 includes two tabs 12, which are a positive tab and a negative tab, respectively. Either the positive tab or the negative tab may have a first solder mark 121 and a second solder mark 122. The positive tab and the negative tab can be connected to the terminal assembly 30 through a corresponding adapter piece 40. The adapter piece 40 connected to the positive tab or the negative tab may include a fusible part 41.

[0068] The cell 10 can be a stacked cell, which is not only convenient to assemble, but also allows for the production of longer batteries. The cell 10 has a first electrode sheet stacked on top of each other, a second electrode sheet with the opposite electrical charge to the first electrode sheet, and a separator sheet disposed between the first electrode sheet and the second electrode sheet, so that multiple pairs of first electrode sheets and second electrode sheets are stacked to form a stacked cell.

[0069] The battery cell 10 can also be a wound battery cell, which is obtained by winding the first electrode, the second electrode with the opposite electrical polarity to the first electrode, and the separator between the first electrode and the second electrode.

[0070] In one embodiment, the cross-sectional discontinuity of the overlapping area of ​​the first solder mark 121 and the second solder mark 122 of the tab 12 is no greater than 30%, thereby ensuring that multiple individual tabs of the tab 12 can form reliable contact, thus ensuring the current carrying capacity of the tab 12 and the welding stability of the tab 12 and the cover plate assembly, thereby improving the current carrying capacity of the battery. The second solder mark 122 is a hollow solder mark, and the space 123 of the second solder mark 122 can serve as a heat dissipation space. Although the heat of the hollow solder mark is more concentrated, the space 123 can serve as a heat dissipation space, and the first solder mark 121 improves the strength of the tab 12. Therefore, the hollow solder mark is heated more evenly, thereby reducing the discontinuity phenomenon of the hollow solder mark and improving the connection capability of the tab 12.

[0071] It should be noted that the tab 12 may include m individual tabs. By performing metallographic testing on the cross-section of the overlapping area of ​​the first solder mark 121 and the second solder mark 122, and observing one cross-section, the number of adjacent individual tabs that do not form a connection can be calculated as n, that is, the number of individual tabs that do not form a connection with the first solder mark 121 and the second solder mark 122 is n. The tomographic rate of the cross-section of the overlapping area of ​​the first solder mark 121 and the second solder mark 122 of the tab 12 is n / m. Alternatively, the tab 12 may include m individual tabs. By performing metallographic testing on the cross-section of the overlapping area of ​​the first solder mark 121 and the second solder mark 122, and observing two cross-sections, the number of adjacent individual tabs that do not form a connection can be calculated as n1 from one cross-section and as n2 from the other cross-section. The tomographic rate of the cross-section of the overlapping area of ​​the first solder mark 121 and the second solder mark 122 of the tab 12 is (n1+n2) / 2m. Specifically, the tabs 12 forming the first weld mark 121 and the second weld mark 122 are cut, and only the sample formed by the welded area is retained. The sample is placed in a mold, and high-definition crystal glue can be mixed in a ratio of 40:1:1 and poured into the mold. After curing, the sample is removed. The sample is cut open using a cutting machine, exposing at least the cross-section of the overlapping area of ​​the first weld mark 121 and the second weld mark 122. For example, a sample is cut in the middle, thus forming two samples that can be observed, i.e., two cross-sections can be observed. The sample is then polished, etched, and the fracture is observed using a microscope, and the number of fractures is recorded.

[0072] An embodiment of the present invention also provides a battery pack including the battery described above.

[0073] A battery pack according to one embodiment of the present invention includes a battery, the battery including a cell 10, the cell 10 including a cell body 11 and a tab 12 extending from the cell body 11. By forming a first solder mark 121 and a second solder mark 122 on the tab 12, the second solder mark 122 covers the first solder mark 121, and the second solder mark 122 forms a circumferentially closed space 123 to expose a part of the first solder mark 121. That is, when welding the tab 12 to the cover plate assembly, the tab 12 is welded twice, and a hollow second solder mark 122 is formed. This can better control the welding energy and better achieve heat dissipation, so that the welding heat is not concentrated and the heat distribution is more uniform, thereby improving the welding quality and thus improving the performance of the battery pack.

[0074] Adjacent batteries can be connected via a busbar.

[0075] In one embodiment, the battery pack is a battery module or a battery pack.

[0076] The battery module includes multiple batteries, and may also include end plates and side plates for securing the batteries. The batteries can be prismatic, meaning they can be square.

[0077] It should be noted that, in combination Figure 5 As shown, multiple batteries can be assembled into a battery module 2 and then placed inside the battery housing 1. The multiple batteries can be fixed using end plates and side plates. Alternatively, multiple batteries can be directly placed inside the battery housing, eliminating the need to group them together; in this case, the end plates and side plates can be removed.

[0078] An embodiment of the present invention also provides a battery manufacturing method, please refer to... Figure 6 Battery manufacturing methods include:

[0079] S101, pre-weld multiple single-piece tabs on the battery cell body 11 to form a first solder mark 121 on the tab 12;

[0080] S103, the pole post assembly 30 of the cover plate assembly is welded to the pole tab 12 to form a second solder mark 122 on the pole tab 12, such that the second solder mark 122 covers the first solder mark 121, and the second solder mark 122 forms a circumferentially closed space 123 to expose the first solder mark 121; or,

[0081] The adapter piece 40 of the cover plate assembly is welded to the tab 12 to form a second solder mark 122 on the tab 12, such that the second solder mark 122 covers the first solder mark 121, and the second solder mark 122 forms a circumferentially closed space 123 to expose the first solder mark 121.

[0082] In one embodiment of the present invention, a battery manufacturing method forms a first solder mark 121 by pre-welding the tab 12, and then welds the cover plate assembly to the tab 12 on the first solder mark 121 to form a second solder mark 122. That is, the tab 12 is welded twice, and the second solder mark 122 forms a circumferentially closed space 123, thereby exposing a part of the first solder mark 121, that is, forming a hollow second solder mark 122. This allows for better control of welding energy and better heat dissipation, resulting in less concentrated welding heat and a more uniform heat distribution, thereby improving welding quality.

[0083] In one embodiment, the first weld mark 121 can be formed by pre-welding the tab 12 directly. That is, before welding the tab 12 to the cover plate assembly, the tab 12 is pre-welded, which combines the individual tabs of the tab 12 together and improves the structural strength of the tab 12 to a certain extent. Therefore, when welding the tab 12 to the cover plate assembly, even if the welding energy is relatively large, the presence of the first weld mark 121 and the second weld mark 122 based on the first weld mark 121 greatly reduce the probability of damage to the tab 12 during secondary welding. Furthermore, the second weld mark 122 is a hollow weld mark, and the space 123 of the hollow weld mark can serve as a heat dissipation space. The weld width is smaller than that of a solid weld mark, which is conducive to uniform temperature distribution and reduces the likelihood of delamination and uneven weld mark surface. Thus, a high-quality weld mark is obtained through the hollow weld mark.

[0084] In one embodiment, the first solder mark 121 may be a pre-welding of the tab 12 and the cover plate assembly, that is, by a first welding with relatively low welding energy, the individual tabs of the tab 12 are combined together, and of course, the tab 12 and the cover plate assembly are also connected. Then, by a second welding with relatively high welding energy, the tab 12 and the cover plate assembly are stably connected, and a second solder mark 122 is formed on the first solder mark 121.

[0085] In one embodiment, the first welding forms a first weld mark 121, and the second welding forms a second weld mark 122. The first welding method can be either ultrasonic welding or laser welding. Correspondingly, the second welding method can be either ultrasonic welding or laser welding, as long as the stability of the connection can be guaranteed and the tab 12 will not be damaged during the first welding.

[0086] In one embodiment, a first solder mark 121 is formed on the tab 12 by ultrasonic welding, and a second solder mark 122 is formed by laser welding of the tab 12 and the pole assembly 30.

[0087] In one embodiment, a first solder mark 121 is formed on the tab 12 by ultrasonic welding, and a second solder mark 122 is formed by laser welding of the tab 12 and the adapter piece 40.

[0088] In one embodiment, a fused portion 41 is formed on the adapter piece 40, which reduces the space in the adapter piece 40 for connecting the tab 12 and the terminal assembly 30. The welding area between the adapter piece 40 and the tab 12 determines the current carrying capacity of the battery. In this embodiment, by forming the first solder mark 121 and the second solder mark 122 sequentially, and the second solder mark 122 being formed on the first solder mark 121, the hollow second solder mark 122 can better control the welding energy and better achieve heat dissipation, making the welding heat less concentrated and the heat distribution more uniform. Therefore, it can be ensured that the adapter piece 40 and the tab 12 can have a reliable welding area, thereby forming a stable connection in some space, thus ensuring the current carrying capacity of the battery.

[0089] In one embodiment, the second weld mark 122 is formed by a circular spiral welding path, which not only facilitates the formation of the circular second weld mark 122, but also ensures welding quality and avoids the delamination rate of the tab 12 from exceeding 30%.

[0090] In one embodiment, the second weld mark 122 is formed using a sinusoidal welding path or a cosine welding path, which not only facilitates the formation of a circular second weld mark 122, but also ensures welding quality and prevents the delamination rate of the tab 12 from exceeding 30%.

[0091] In one embodiment, forming the second weld mark 122 includes: establishing a welding trajectory; and welding along the welding trajectory using a sinusoidal or cosine welding path to form the second weld mark 122. That is, when welding with the welding head, a welding trajectory can be established first. This welding trajectory is the approximate shape of the final formed second weld mark 122, so that when the welding head welds along the welding trajectory, it can fill the welding trajectory with a sinusoidal or cosine welding path to form the second weld mark 122.

[0092] Specifically, a welding trajectory can be established through a control program. The welding trajectory can be considered as a preset virtual welding path, and the actual path of the welding head is the welding trajectory. However, the welding is carried out in the form of a sine or cosine line. It can be further understood that the welding trajectory is ultimately formed by splicing together multiple sine or cosine lines.

[0093] In one embodiment, establishing a welding trajectory includes: determining the radius value of a first direction; determining the radius value of a second direction, wherein the first direction is perpendicular to the second direction, which can be considered as determining the approximate shape of the welding trajectory; and determining the starting angle and ending angle of the welding, wherein the starting angle and ending angle are 0° and 360° respectively, so that the welding trajectory is a circumferentially closed trajectory, and ultimately a circumferentially closed second weld mark 122 can be formed.

[0094] The radius values ​​in the first and second directions roughly determine the shape of the welding trajectory. If the radius value in the first direction is equal to the radius value in the second direction, the welding trajectory is circular, ultimately forming a ring-shaped second weld mark 122. If the radius value in the first direction is not equal to the radius value in the second direction, the welding trajectory is elliptical.

[0095] In one embodiment, welding is performed along the welding trajectory using a sinusoidal or cosine welding path, including: determining the pulse width of the sinusoidal or cosine line to control the travel path of the welding head and thus control the weld density; determining the frequency of the sinusoidal or cosine line to control the weld width of the formed second weld mark 122, thereby ensuring that the second weld mark 122 can reliably connect to the tab 12; and controlling the operation of the welding head, i.e., the welding head can travel along the welding trajectory in a sinusoidal or cosine manner.

[0096] In one embodiment, the battery manufacturing method is used to form the battery described above. The relevant structures and dimensions in the battery manufacturing method can be referenced to the battery described above, and will not be repeated here.

[0097] Other embodiments of this disclosure will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This disclosure is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not disclosed herein. The specification and exemplary embodiments are to be considered exemplary only, and the true scope and spirit of this disclosure are indicated by the appended claims.

[0098] It should be understood that this disclosure is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of protection of this disclosure is limited only by the appended claims.

Claims

1. A battery, characterized in that, The device includes a battery cell (10), which comprises a battery cell body (11) and a tab (12). The tab (12) extends from the battery cell body (11) and includes a first solder mark (121) and a second solder mark (122). The second solder mark (122) covers the first solder mark (121) and forms a circumferentially enclosed space (123) to expose the first solder mark (121). The area of ​​the space (123) occupies 5%-30% of the sum of the area of ​​the second solder mark (122) and the area of ​​the space (123). The area of ​​the second solder mark (122) is 10 mm². 2 -200 mm 2 The electrode tab (12) includes multiple single electrode tabs, the number of which is 100-200. The cross-sectional area of ​​the overlapping region of the first solder mark (121) and the second solder mark (122) of the electrode tab (12) has a tortuosity of no more than 30%.

2. The battery according to claim 1, characterized in that, The space (123) is circular.

3. The battery according to claim 2, characterized in that, The second solder mark (122) is a ring.

4. The battery according to any one of claims 1 to 3, characterized in that, The weld width of the second weld mark (122) is 1.5mm-6mm.

5. The battery according to any one of claims 1 to 3, characterized in that, The first solder mark (121) is square.

6. The battery according to claim 5, characterized in that, The size of the first solder mark (121) is 5mm×5mm-20mm×20mm.

7. The battery according to any one of claims 1 to 3, characterized in that, The second solder mark (122) is located in the middle of the first solder mark (121).

8. The battery according to any one of claims 1 to 3, characterized in that, The tab (12) includes multiple single tabs, and the first solder mark (121) is formed by pre-soldering the tab (12) to combine the multiple single tabs; The first weld mark (121) and the second weld mark (122) are formed sequentially. The first weld mark (121) is an ultrasonic weld mark, and the second weld mark (122) is a laser weld mark.

9. The battery according to any one of claims 1 to 3, characterized in that, The battery also includes a cover assembly, and the second solder mark (122) is formed by welding the tab (12) and the cover assembly to connect the tab (12) and the cover assembly.

10. The battery according to claim 9, characterized in that, The cover plate assembly includes a cover plate (20) and a pole post assembly (30), the pole post assembly (30) being disposed on the cover plate (20), and the second solder mark (122) being formed by welding the tab (12) and the pole post assembly (30) to connect the tab (12) and the pole post assembly (30).

11. The battery according to claim 9, characterized in that, The cover plate assembly includes a cover plate (20), a pole assembly (30), and an adapter plate (40). The pole assembly (30) is disposed on the cover plate (20), and the adapter plate (40) is connected to the pole assembly (30). The second solder mark (122) is formed by welding the tab (12) and the adapter plate (40) to connect the tab (12) and the adapter plate (40).

12. The battery according to claim 11, characterized in that, The adapter piece (40) includes a fusible part (41).

13. A method for manufacturing a battery, characterized in that, include: Multiple single-piece tabs on the battery cell body (11) are pre-welded to form a first solder mark (121) on the tab (12). The pole post assembly (30) of the cover plate assembly is welded to the pole lug (12) to form a second solder mark (122) on the pole lug (12), such that the second solder mark (122) covers the first solder mark (121), and the second solder mark (122) forms a circumferentially closed space (123) to expose the first solder mark (121); or, The adapter piece (40) of the cover plate assembly is welded to the tab (12) to form a second solder mark (122) on the tab (12), such that the second solder mark (122) covers the first solder mark (121), and the second solder mark (122) forms a circumferentially closed space (123) to expose the first solder mark (121). The area of ​​the space (123) occupies 5%-30% of the sum of the area of ​​the second solder mark (122) and the area of ​​the space (123), and the area of ​​the second solder mark (122) is 10 mm. 2 -200 mm 2 The electrode tab (12) includes multiple single electrode tabs, the number of which is 100-200. The cross-sectional area of ​​the overlapping region of the first solder mark (121) and the second solder mark (122) of the electrode tab (12) has a tortuosity of no more than 30%.

14. The battery manufacturing method according to claim 13, characterized in that, A fusible portion (41) is formed on the adapter piece (40).

15. The battery manufacturing method according to claim 13 or 14, characterized in that, The second weld mark (122) is formed using a sinusoidal welding path, or the second weld mark (122) is formed using a cosine welding path.

16. The battery manufacturing method according to claim 15, characterized in that, Forming the second solder mark (122) includes: Establish welding trajectory; Welding is performed along the welding trajectory using either the sine or cosine welding path to form the second weld mark (122).

17. The battery manufacturing method according to claim 16, characterized in that, Establishing the welding trajectory includes: Determine the radius value in the first direction; Determine the radius value of the second direction, wherein the first direction is perpendicular to the second direction; The starting angle and the ending angle of the welding are determined, wherein the starting angle and the ending angle are 0° and 360°, respectively.

18. The battery manufacturing method according to claim 17, characterized in that, The radius value in the first direction is equal to the radius value in the second direction.

19. The battery manufacturing method according to claim 16, characterized in that, Welding is performed along the welding trajectory using either the sinusoidal welding path or the cosine welding path, including: Determine the pulse width of the sine or cosine line; Determine the frequency of the sine or cosine line; Control the operation of the welding head.

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