Battery cell, battery welding method, battery device, and electric device

Abstract

The application discloses a battery monomer, a battery welding method, a battery device and a power utilization device, and relates to the technical field of batteries. The battery monomer comprises a first workpiece and a second workpiece, the first workpiece is located above the second workpiece, and the overlap area of the first workpiece and the second workpiece is welded and connected and has a welding seam. A first welding track of the battery monomer extends along the length direction of the welding seam and reciprocally extends along the width direction of the welding seam, the first welding track comprises a first welding section and a second welding section, and a second welding track of the battery monomer coincides with at least one of the first welding section and the second welding section. The technical scheme of the application can reduce the generation of welding slag in the process of welding two workpieces of the battery monomer.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a battery cell, a battery welding method, a battery device, and an electrical device. Background Technology

[0002] Energy conservation and emission reduction are key to the sustainable development of the automotive industry, and electric vehicles, due to their energy-saving and environmentally friendly advantages, have become an important component of this sustainable development. For electric vehicles, battery technology is a crucial factor in their development.

[0003] During battery assembly, the terminals and current collector need to be welded together. During the welding process, weld slag is easily formed, resulting in a high product defect rate. If the weld slag falls into the filling hole, it will increase the risk of battery self-discharge and seriously affect the battery performance. Summary of the Invention

[0004] The main objective of this application is to provide a battery cell, a battery welding method, a battery device, and an electrical device, which aim to reduce the generation of welding slag during the welding process of two workpieces of a battery cell.

[0005] To achieve the above objectives, the present application proposes a battery cell comprising a first workpiece and a second workpiece, wherein the first workpiece is located above the second workpiece, and the overlapping area of ​​the first workpiece and the second workpiece is welded together to form a weld seam.

[0006] The first welding trajectory of the battery cell extends along the length direction of the weld and reciprocates along the width direction of the weld. The first welding trajectory includes a first welding segment and a second welding segment. The second welding trajectory of the battery cell coincides with at least one of the first welding segment and the second welding segment.

[0007] In the process of welding the first and second workpieces of the battery cell, the laser beam moves along the first and second welding paths respectively, and the second welding path coincides with at least one of the first welding segment in the starting area and the second welding segment in the ending area of ​​the first welding path. This allows for two welding processes at the arc-starting segment and / or the ending segment of the weld. With this setup, the slag generated during the first welding will be remelted during the second welding to form a molten pool, which can avoid the generation and residue of slag at the arc-starting point.

[0008] In addition, by making the first welding trajectory of the first and second workpieces an oscillating welding trajectory, the laser beam can be oscillating during welding, which can make the weld meet the requirements of surface weld width and effective weld width. At the same time, it can reduce the flow rate and temperature gradient of the molten pool, improve the uniformity of energy distribution, thereby improving welding stability, reducing the occurrence of pinhole bursts, and reducing the defect rate of weld slag. This reduces the generation of weld slag, thereby reducing the risk of weld slag falling into the liquid injection hole of the battery cell and ensuring the performance of the battery cell.

[0009] In one embodiment, the second welding trajectory includes a third welding segment, the weld includes an arc-starting segment, the arc-starting segment includes the first welding segment and the third welding segment located below the first welding segment, the starting end of the third welding segment coincides with the first welding trajectory, and the ending end of the third welding segment is located at the same end of the weld as the starting end of the first welding segment.

[0010] Using the above method, during the welding of the first and second workpieces, the laser beam moves sequentially along the third welding segment and the first welding trajectory. The third welding segment of the second welding trajectory serves as the arc-starting trajectory, and the starting end of the third welding segment is the arc-starting position for welding. Thus, as the laser beam moves along the first welding trajectory, it will pass through the arc-starting position again. This allows the weld slag generated at the arc-starting position to be remelted to form a molten pool, thus avoiding the generation and residue of weld slag at the arc-starting point.

[0011] In one embodiment, the depth of the arc-starting segment increases progressively along the direction from the first welding segment to the second welding segment.

[0012] In this configuration, during the two welding processes of the laser beam on the arc-starting segment, the laser energy of the laser beam increases as it moves along the third welding segment of the second welding trajectory. This avoids the generation of excessive welding slag as the laser beam moves along the third welding segment, and the depth of the arc-starting segment is set to increase gradually.

[0013] In one embodiment, the second welding trajectory includes a fourth welding segment, and the weld further includes a finishing segment, which includes the second welding segment and a fourth welding segment located above the second welding segment, wherein the end of the second welding segment and the beginning of the fourth welding segment are located at the same end of the weld.

[0014] This setup involves controlling the laser beam to move along the first welding trajectory to the end of the weld, and then controlling the laser beam to move in the opposite direction along the fourth welding segment. This extends the existence time of the molten pool in the finishing arc crater, allowing the molten pool at the welding end position a longer time to solidify. This prevents the molten pool from shrinking too slowly during solidification, ensuring that the metal can fully retract to fill the middle area of ​​the weld, and reducing the risk of cracks, pinholes, and weld slag.

[0015] In one embodiment, the fourth welding segment is arranged in a spiral shape.

[0016] This setup ensures uniform energy distribution in the finishing arc crater area during the reflow process, and helps extend the solidification time of the molten pool, reducing the risk of cracks, pinholes, and weld slag, thus improving the welding effect.

[0017] In one embodiment, the first workpiece has a remelting layer on the side opposite to the second workpiece, and the remelting layer is formed at the edge of the weld.

[0018] This setup involves remelting the edges of the weld after welding to form a remelted layer. This allows the generated slag to be remelted to form a molten pool, thus avoiding the generation and residue of slag.

[0019] In one embodiment, the grain size in the remelted layer is smaller than the grain size in the weld.

[0020] Using the above method, the nucleation rate of the remelted layer is much greater than the growth rate due to the extremely high cooling rate of the molten pool, resulting in finer equiaxed crystals. The fine grain structure has higher strength and better plasticity, improving the impact toughness of the welded joint and reducing the risk of brittle fracture.

[0021] In one embodiment, the remelting layer is disposed around the weld area.

[0022] By using the above method, the periphery of the weld can be remelted, effectively cleaning the welding slag generated during the welding process and reducing the risk of welding slag entering the injection hole and flowing to the next process.

[0023] In one embodiment, the first workpiece is configured as an electrode post, the second workpiece is configured as a current collector, the battery cell is provided with a liquid injection hole penetrating the electrode post and the current collector, and the weld extends circumferentially along at least a portion of the liquid injection hole.

[0024] This configuration allows the pole and collector plate to be welded and fixed in place more effectively.

[0025] In one embodiment, when a remelting layer is provided, the width of the remelting layer located on the side of the weld near the injection hole is not less than the width of the remelting layer located on the side of the weld away from the injection hole.

[0026] This setup allows for thorough remelting of the area near the injection hole, effectively cleaning the weld slag on the side of the weld closest to the injection hole and reducing the risk of weld slag falling into the injection hole.

[0027] In one embodiment, the weld includes a first fusion zone and a second fusion zone along the width direction of the weld.

[0028] Wherein, the grain size in the first fusion zone is smaller than the grain size in the second fusion zone; this setting method, that is, through the reciprocating oscillating welding method, makes a part of the weld seam form relatively fine equiaxed grains. The fine grain structure has higher strength and better plasticity, which is beneficial to improving the impact toughness of the welded joint and reducing the risk of brittle fracture.

[0029] And / or, the grain orientation in the first fusion zone is different from that in the second fusion zone. With this arrangement, the grains are spatially distributed in a multi-directional staggered manner, and the grain boundaries are tortuous, which can hinder the straight propagation of cracks and improve the toughness of the weld.

[0030] This application also proposes a battery welding method for welding a first workpiece and a second workpiece of a battery cell as described in any of the foregoing embodiments. The battery welding method includes the following steps:

[0031] The laser beam is controlled to weld a first welding trajectory and a second welding trajectory at the overlap position of the first workpiece and the second workpiece to form a weld. The first welding trajectory includes a first welding segment located at the arc initiation section and a second welding segment located at the end section. The second welding trajectory coincides with at least one of the first welding segment and the second welding segment.

[0032] The step of controlling the laser beam to weld the first welding trajectory includes:

[0033] The laser beam is controlled to move along the length of the preset weld and oscillate back and forth along the width of the weld to perform welding on the overlapping area of ​​the first workpiece and the second workpiece.

[0034] In the technical solution of this application, during the welding process of the first workpiece and the second workpiece, the laser beam moves along the first welding trajectory and the second welding trajectory respectively, and makes the second welding trajectory coincide with at least one of the first welding segment in the starting area and the second welding segment in the ending area of ​​the first welding trajectory, so that two welding processes can be performed in the arc-starting segment and / or the ending segment of the weld. With this setting, the slag generated during the first welding will be remelted during the second welding to form a molten pool, which can avoid the generation and residue of slag at the arc-starting point.

[0035] In addition, during the welding process of the first and second workpieces, the laser beam is used to perform oscillating welding, which can make the weld meet the requirements of surface weld width and effective weld width, while reducing the flow rate and temperature gradient of the molten pool, improving the uniformity of energy distribution, thereby improving welding stability, reducing the occurrence of pinholes and bursts, and reducing the defect rate of weld slag.

[0036] In one embodiment, the first welding trajectory is set as a sinusoidal oscillating trajectory.

[0037] By using the above method, the effective weld width can be maximized under the same surface weld width and effective weld depth, thereby ensuring that the weld meets the requirements of surface weld width and effective weld width.

[0038] In one embodiment, the second welding trajectory includes a third welding segment located at the arc initiation segment, the end of which is connected to the starting position of the first welding trajectory;

[0039] The laser beam moves sequentially along the third welding segment and the first welding trajectory, with the third welding segment located in the molten pool region formed during welding along the first welding trajectory.

[0040] Using the above method, the laser beam will also pass through the third welding section when it moves along the first welding trajectory. This allows the weld slag generated at the arc initiation position of the third welding section to be remelted to form a molten pool, thus avoiding the generation and residue of weld slag at the arc initiation point.

[0041] In one embodiment, the laser energy of the laser beam at the arc-starting position of the third welding segment does not exceed 50% of the laser energy of the laser beam during its movement along the first welding trajectory.

[0042] By adopting the above method, welding slag at the arc initiation point can be avoided or reduced, thus preventing defects such as pinholes and bursts.

[0043] In one embodiment, the laser energy gradually increases as the laser beam moves along the third welding segment.

[0044] By using the above method, excessive welding slag can be avoided during the process of the laser beam moving along the third welding section.

[0045] In one embodiment, the oscillation amplitude of the laser beam reciprocating along the width direction of the weld is not less than the ratio between the welding speed and the oscillation frequency of the laser beam.

[0046] By using the above method, it can be ensured that the final weld meets the requirements for surface weld width and effective weld width.

[0047] In one embodiment, the second welding trajectory further includes a fourth welding segment located at the end segment, and the step of controlling the laser beam to weld the first welding trajectory and the second welding trajectory at the overlap position of the first workpiece and the second workpiece respectively includes:

[0048] Control the laser beam to weld along the first welding trajectory;

[0049] The laser beam is controlled to move from the end of the first welding trajectory along the fourth welding segment to perform a re-welding process above the second welding segment.

[0050] By adopting the above method, the existence time of the molten pool in the finishing arc crater can be extended, so that the molten pool at the welding end position has a longer time to solidify. This avoids the molten pool shrinking in time during solidification, ensuring that the metal can fully shrink back to fill the middle area of ​​the weld, and reducing the risk of cracks, pinholes, and weld slag.

[0051] In one embodiment, the fourth welding segment has a spiral trajectory.

[0052] By adopting the above method, the energy distribution in the finishing arc crater area can be made uniform during the reflow process, and it is beneficial to extend the solidification time of the molten pool, reduce the risk of cracks, pinholes, and weld slag, and improve the welding effect.

[0053] In one embodiment, the laser energy of the laser beam is gradually reduced during the reflow process.

[0054] Using the above method avoids excessive laser energy during the reflow process, which could burn through the finishing arc crater and also helps reduce the amount of welding slag generated in the finishing arc crater.

[0055] In one embodiment, after the step of controlling the laser beam to move along the length direction of a preset weld and oscillate back and forth along the width direction of the weld to weld the overlapping area of ​​the first workpiece and the second workpiece to form a weld, the method further includes:

[0056] The laser beam is controlled to remelt the electrode surface at the edge of the weld.

[0057] This setup involves remelting the edges of the weld after welding, which allows the generated slag to reform into a molten pool, thus preventing the formation and residue of slag.

[0058] In one embodiment, the remelting trajectory of the laser beam is arranged around the weld.

[0059] By using the above method, the edges of the weld can be remelted, effectively cleaning the welding slag generated during the welding process and reducing the risk of welding slag entering the injection hole and flowing to the next process.

[0060] In one embodiment, the battery cell is provided with a liquid injection hole that passes through the first workpiece and the second workpiece, and the laser beam performs multiple remelting processes on the edge of the weld near the liquid injection hole.

[0061] Using the above method, the area near the injection hole can be fully remelted, and the weld slag on the side of the weld near the injection hole can be thoroughly cleaned, reducing the risk of weld slag falling into the injection hole.

[0062] In one embodiment, before the step of controlling the laser beam to move along the length direction of a preset weld and oscillate back and forth along the width direction of the weld to weld the overlapping area of ​​the first workpiece and the second workpiece, the method further includes:

[0063] Impurities on the surface of the electrode column are removed by negative pressure dust removal.

[0064] By adopting the above method, particulate impurities or other contaminants on the electrode surface can be avoided, maintaining the cleanliness of the electrode surface and reducing the welding slag generated during the welding process. Furthermore, the electrode can be cleaned without direct contact with the surface, and impurities on the electrode surface, once absorbed, will not be scattered to the welding location or other parts of the production line, minimizing the impact on the production line and process.

[0065] In one embodiment, the dust extraction duct is inclined upward relative to the horizontal direction.

[0066] Using the above method, the flow of air driven by the dust removal process from the welding area into the dust collection duct is relatively smooth, which is conducive to improving the dust removal effect, and the dust collection duct does not occupy much space in the vertical direction.

[0067] In one embodiment, the battery cell is provided with a liquid injection hole that passes through the first workpiece and the second workpiece. The weld extends circumferentially along at least a portion of the liquid injection hole. The liquid injection hole is blocked by a sealing structure. A protective gas channel is provided in the sealing structure. The outlet of the protective gas channel is oriented toward the welding area.

[0068] The battery welding method also includes blowing protective gas into the welding area during the welding process.

[0069] In one embodiment, the sealing structure includes:

[0070] A pressure block, wherein the pressure block is disposed opposite to the electrode post and is provided with a vent port disposed opposite to the injection hole; the surface of the pressure block facing away from the electrode post is provided with a vent groove communicating with the vent port; and

[0071] The plug includes a mounting plate and a sealing part. The mounting plate is located on the side of the pressure block facing away from the pole post. The sealing part passes through the vent and is inserted into the injection hole to block the injection hole. The sealing part is spaced apart from the edge of the vent, and an air outlet gap is formed between the sealing part and the edge of the vent.

[0072] The gas guide groove and the gas outlet gap are connected to form the protective gas channel, and the protective gas passes through the gas guide groove and the gas outlet gap in sequence to be blown toward the welding area.

[0073] By using the above method, the injection hole can be effectively sealed using the sealing structure, preventing welding slag or other impurities from entering the welding area, and ensuring that the shielding gas is accurately blown towards the welding area, while also reducing the leakage of shielding gas.

[0074] In one embodiment, the pressure block is provided with at least two air guide grooves, which are arranged circumferentially along the air inlet.

[0075] This configuration helps to increase the amount of air entering the protective air channel and improve the blowing effect.

[0076] In one embodiment, the pressure block and the plug are separate components.

[0077] Using the above method, when the plug needs to be cleaned or replaced, it is not necessary to remove the entire sealing structure; only the plug itself needs to be removed, thus improving ease of use.

[0078] In one embodiment, the air guide groove is tangent to the air inlet.

[0079] This configuration allows the shielding gas to flow out along the edge of the vent when it flows from the gas guide groove, creating a ring-blowing effect. This ensures that the shielding gas is blown evenly into the welding area. Furthermore, it prevents the gas from blowing against the airflow flowing into the vent from other gas guide grooves, thereby reducing mutual interference between airflows and preventing a decrease in airflow velocity, thus ensuring both the blowing effect and the welding effect.

[0080] This application also proposes a battery device comprising the battery cell described in any of the foregoing embodiments.

[0081] This application also proposes an electrical device, including a battery cell or battery device as described in any of the foregoing embodiments.

[0082] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the other objects, features and advantages of this application more obvious and understandable, specific embodiments of this application are given below. Attached Figure Description

[0083] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0084] Figure 1 A cross-sectional view of an embodiment of a battery cell provided in this application;

[0085] Figure 2 An exploded view of one embodiment of the battery cell provided in this application;

[0086] Figure 3 This is a schematic diagram of the laser beam movement trajectory in the battery welding method provided in this application;

[0087] Figure 4 A cross-sectional view showing the welding positions of the electrode posts and current collectors in the battery cell provided in this application;

[0088] Figure 5 This is a schematic diagram showing the welding positions of the battery cells in this application;

[0089] Figure 6 IPF diagrams of weld interface regions in some embodiments of this application;

[0090] Figure 7 A schematic diagram of an embodiment of the sealing structure used in the battery welding method provided in this application;

[0091] Figure 8 for Figure 7 A schematic diagram of an embodiment of the plug structure of the central sealing structure;

[0092] Figure 9 A structural diagram of an embodiment of the battery device provided in this application;

[0093] Figure 10 A structural diagram of an embodiment of the vehicle provided in this application.

[0094] Explanation of icon numbers:

[0095] 10. Battery cell; 11. Terminal post; 12. Current collector; 13. Housing; 14. Core; 16. Weld; 161. Finishing section; 162. First fusion zone; 163. Second fusion zone; 164. Arc initiation section; 17. Remelted layer; 18. Injection hole; 101. First welding trajectory; 1011. First welding segment; 1012. Second welding segment; 102. Second welding trajectory; 1021. Third welding segment; 1022. Fourth welding segment; 103. Remelted trajectory;

[0096] 1000, Vehicle; 100, Battery unit; 20, Housing; 21, First part; 22, Second part; 200, Controller; 300, Motor; 3000, Sealing structure; 3001, Pressure block; 3002, Plug; 3003, Mounting plate; 3004, Sealing part; 3005, Vent; 3006, Air guide channel.

[0097] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0098] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0099] It should be noted that if the embodiments of this application involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indicators will also change accordingly.

[0100] Furthermore, if the embodiments of this application involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or" or "and / or" throughout the text includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution that simultaneously satisfies A and B. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed in this application.

[0101] Energy conservation and emission reduction are key to the sustainable development of the automotive industry, and electric vehicles, due to their energy-saving and environmentally friendly advantages, have become an important component of this sustainable development. For electric vehicles, battery technology is a crucial factor in their development.

[0102] During battery assembly, the terminals and current collector need to be welded together. During the welding process, weld slag is easily formed, resulting in a high product defect rate. If the weld slag falls into the filling hole, it will increase the risk of battery self-discharge and seriously affect the battery performance.

[0103] Based on the above considerations, this application proposes a battery cell, which includes a first workpiece and a second workpiece. The first workpiece is located above the second workpiece, and the overlapping area of ​​the first workpiece and the second workpiece is welded together to form a weld. The first welding trajectory of the battery cell extends along the length direction of the weld and extends back and forth along the width direction of the weld. The first welding trajectory includes a first welding segment and a second welding segment. The second welding trajectory of the battery cell partially overlaps with the first welding segment or the second welding segment.

[0104] In the process of welding the first and second workpieces of the battery cell, the laser beam moves along the first and second welding paths respectively, and the second welding path coincides with at least one of the first welding segment in the starting area and the second welding segment in the ending area of ​​the first welding path. This allows for two welding processes at the arc-starting segment and / or the ending segment of the weld. With this setup, the slag generated during the first welding will be remelted during the second welding to form a molten pool, which can avoid the generation and residue of slag at the arc-starting point.

[0105] The battery cell 10 and battery device 100 mentioned in the embodiments of this application will be described below.

[0106] The battery device 100 mentioned in the embodiments of this application may include one or more battery cell assemblies for providing voltage and capacity. A battery cell assembly may include multiple battery cells 10, which are connected in series, parallel, or mixed connections via busbars.

[0107] In some embodiments, the battery cell assembly is typically formed by arranging a plurality of battery cells 10.

[0108] As an example, a battery cell assembly can be a battery module, which is formed by arranging and fixing multiple battery cells 10 together to form an independent module. As an example, a battery module can be formed by bundling multiple battery cells 10 together with cable ties.

[0109] Please refer to Figure 9 In some embodiments, the battery device 100 may be a battery pack, which includes a housing 20 and one or more battery cell assemblies housed within the housing 20. As an example, the battery cell assembly may be a battery module, which can be housed within the housing 20 by securing the battery module to the housing 20. Alternatively, as an example, the battery cell assembly may be housed within the housing 20 by directly securing multiple battery cells 10 to the housing 20.

[0110] The housing 20 provides installation space for the battery cell 10, and the housing 20 can adopt various structures. In some embodiments, the housing 20 may include a first part 21 and a second part 22, which overlap each other, and together define an installation space for accommodating the battery cell 10. The second part 22 may be a hollow structure with one end open, and the first part 21 may be a plate-like structure, with the first part 21 covering the open side of the second part 22 so that the first part 21 and the second part 22 together define the installation space; alternatively, the first part 21 and the second part 22 may both be hollow structures with one side open, with the open side of the first part 21 covering the open side of the second part 22. Of course, the housing 20 formed by the first part 21 and the second part 22 can be of various shapes, such as a cylinder, a cuboid, etc.

[0111] In the battery device 100, there can be multiple battery cells 10, which can be connected in series, parallel, or in a mixed configuration. A mixed configuration means that multiple battery cells 10 are connected in both series and parallel connections. Multiple battery cells 10 can be directly connected in series, parallel, or in a mixed configuration, and then the entire assembly of the multiple battery cells 10 is housed within the housing 20. Alternatively, multiple battery cells 10 can first be connected in series, parallel, or in a mixed configuration to form a battery module, and then multiple battery modules can be connected in series, parallel, or in a mixed configuration to form a whole, which is also housed within the housing 20. The battery device 100 may also include other structures; for example, it may include a busbar component for electrical connection between the multiple battery cells 10.

[0112] Each battery cell 10 can be a secondary battery or a primary battery; a secondary battery refers to a battery cell 10 that can be recharged to activate the active materials and continue to be used after it has been discharged.

[0113] The battery cell 10 may include, but is not limited to, lithium-ion battery cell 10, sodium-ion battery cell 10, sodium-lithium-ion battery cell 10, lithium metal battery cell 10, sodium metal battery cell 10, lithium-sulfur battery cell 10, magnesium-ion battery cell 10, nickel-metal hydride battery cell 10, nickel-cadmium battery cell 10, lead-acid battery cell 10, etc.

[0114] As an example, the battery cell 10 can be a cylindrical battery cell, a prismatic battery cell, or a battery cell 10 of other shapes. Prismatic battery cells include square battery cells, blade-shaped battery cells, and multi-prismatic batteries, such as hexagonal prismatic batteries.

[0115] Please refer to Figure 1 and Figure 2The battery cell 10 includes a housing 13, a core 14 and a current collector 12 located within the housing 13. The current collector 12 includes a positive current collector and a negative current collector located at both ends of the core 14. The core 14 is formed by winding a positive electrode sheet, a negative electrode sheet, and a separator. One end of the core 14 has a positive electrode tab connected to the positive electrode sheet, and the other end has a negative electrode tab connected to the negative electrode sheet. The current collector 12 is used to collect and conduct current, with the positive current collector connected to the positive electrode tab and the negative current collector connected to the negative electrode tab. The battery cell 10 also includes a terminal post 11 welded to the current collector 12. The terminal post 11 is at least partially exposed on the outside of the housing 13, serving as one of the connection points between the battery cell 10 and external devices, allowing current to be conducted from the inside of the battery cell 10 to the outside.

[0116] The battery device 100 in this application can be used as a power source or power system for an electrical device. The battery device 100 refers to a single physical module that includes one or more battery cells 10 to provide higher voltage and capacity. This is beneficial to improving the overall performance of the battery device 100 and facilitates the promotion of the battery device 100.

[0117] The aforementioned electrical devices may include, but are not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, rail trains, ships, spacecraft, etc. Among them, electric toys may include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc., and spacecraft may include airplanes, rockets, space shuttles, and spacecraft, etc.

[0118] Please refer to Figure 1 and Figure 3 The battery cell 10 proposed in this application includes a first workpiece and a second workpiece. The first workpiece is located above the second workpiece. The overlapping area of ​​the first workpiece and the second workpiece is welded together to form a weld 16. The first welding trajectory 101 of the weld 16 extends along the length direction of the weld 16 and includes a first welding segment 1011 and a second welding segment 1012. The second welding trajectory 102 of the battery cell 10 coincides with at least one of the first welding segment 1011 and the second welding segment 1012.

[0119] In this embodiment, the first workpiece and the second workpiece can be respectively set as pole post 11 and collector plate 12, the first workpiece and the second workpiece can also be respectively set as cover and shell 13, or the first workpiece and the second workpiece can be respectively set as explosion-proof valve and cover, etc.

[0120] The first workpiece and the second workpiece are welded together by laser penetration welding. The laser penetrates the first workpiece and acts on the second workpiece to form a molten pool at the overlap position of the first and second workpieces. After the molten pool solidifies, a weld 16 is formed to weld the first workpiece and the second workpiece together.

[0121] In this application, during the welding of the first and second workpieces of the battery cell 10, the laser beam moves along the first welding trajectory 101 and the second welding trajectory 102, respectively, and the second welding trajectory 102 coincides with at least one of the first welding segment 1011 in the starting region and the second welding segment 1012 in the ending region of the first welding trajectory 101. For example, the second welding trajectory 102 may include a third welding segment 1021 that coincides with the first welding segment 1011, or it may include a fourth welding segment 1022 that coincides with the second welding segment 1012. That is, when welding the first and second workpieces, two welding processes are performed at the arc-starting segment 164 and / or the ending segment 161 of the weld 16; with this arrangement, the slag generated during the first welding will re-form a molten pool through remelting during the second welding, which can avoid the generation and residue of slag at the arc-starting point.

[0122] Please refer to Figure 3 In one embodiment, the first welding trajectory 101 extends along the length direction of the weld 16 and is provided to extend back and forth along the width direction of the weld 16.

[0123] In this embodiment, during the welding of the first and second workpieces, the laser beam forms a first welding trajectory 101 for oscillating welding. The laser beam moves along the length of the expected weld 16 and simultaneously oscillates along the width of the expected weld 16, causing the first welding trajectory 101 to form a broken line or sinusoidal trajectory. This configuration ensures a uniform distribution of laser energy in the welding area, which helps reduce the molten pool velocity and temperature gradient, improves the uniformity of energy distribution, thereby enhancing welding stability, reducing pinholes and bursts, and lowering the risk of undercut and slag defects in the weld 16. Furthermore, the oscillating laser beam along the width of the weld 16 ensures that the weld 16 meets the requirements for surface weld width and effective weld width.

[0124] Please refer to Figure 3 In one embodiment, the second welding trajectory 102 includes a third welding segment 1021, and the weld 16 includes an arc-starting segment 164. The arc-starting segment 164 includes a first welding segment 1011 and a third welding segment 1021 located below the first welding segment 1011. The starting end of the third welding segment 1021 coincides with the first welding trajectory 101, and the ending end of the third welding segment 1021 is located at the same end of the weld 16 as the starting end of the first welding segment 1011.

[0125] In this embodiment, the laser beam begins welding from the third welding segment 1021 of the second welding trajectory 102. When it moves along the third welding segment 1021 to the end of the first welding trajectory 101, it is at the starting position of the first welding trajectory 101, and then continues welding along the first welding trajectory 101. This ensures that the arc-starting position of the third welding segment 1021 is located within the first welding trajectory 101. Therefore, when the laser beam moves along the first welding trajectory 101, it will also pass through the third welding segment 1021. This allows the weld slag generated at the arc-starting position of the third welding segment 1021 to be remelted to form a molten pool, thus avoiding the generation and residue of weld slag at the arc-starting point.

[0126] In one embodiment, the depth of the arc-starting segment 164 increases progressively along the direction from the first welding segment 1011 to the second welding segment 1012.

[0127] In this embodiment, during the two welding processes of the laser beam on the arc-initiating segment 164, the laser energy of the laser beam can be increased as it moves along the third welding segment 1021. This causes the depth of the arc-initiating segment 164 to increase progressively along the direction from the beginning to the end of the first welding trajectory 101. This progressively increasing depth avoids the generation of excessive weld slag during the arc-initiating welding process as the laser beam moves along the third welding segment 1021.

[0128] Please refer to Figure 3 In one embodiment, the second welding trajectory 102 includes a fourth welding segment 1022, and the weld 16 further includes a finishing segment 161, which includes a second welding segment 1012 and a fourth welding segment 1022 located above the second welding segment 1012. The end of the second welding segment 1012 and the beginning of the fourth welding segment 1022 are located at the same end of the weld 16.

[0129] This setup extends the duration of the molten pool in the finishing arc crater, allowing the molten pool at the welding end position more time to solidify. This prevents the molten pool from shrinking too slowly during solidification, ensuring that the metal can fully retract to fill the central area of ​​weld 16, thus reducing the risk of cracks, pinholes, and weld slag.

[0130] Please refer to Figure 3 In one embodiment, the fourth welding segment 1022 has a spiral trajectory.

[0131] In this embodiment, the fourth welding segment 1022 forms a spiral trajectory, which makes the laser beam move simultaneously along the length and width directions of the weld 16. This can make the energy distribution in the end arc crater area uniform during the back welding process, and it is also beneficial to extend the solidification time of the molten pool, reduce the risk of problems such as undercut and pinhole bursts, and also help to reduce the generation of welding slag and improve the welding effect.

[0132] Please refer to Figure 3 and Figure 5 In one embodiment, a remelting layer 17 is provided on the side of the first workpiece facing away from the second workpiece, and the remelting layer 17 is formed at the edge of the weld 16. In this embodiment, after welding is completed, controlling the laser beam to move along the edge of the weld 16 can remelt all edges of the weld 16, effectively cleaning the welding slag generated during the welding process and reducing the risk of welding slag entering the injection hole 18 and flowing to the next process.

[0133] Please refer to Figure 6 In one embodiment, the grain size in the remelted layer 17 is smaller than the grain size in the weld 16.

[0134] By using the above method, the extremely high cooling rate of the molten pool of the remelted layer 17 during the remelting process leads to a nucleation rate that is much greater than the growth rate, resulting in finer equiaxed crystals. The fine grain structure has higher strength and better plasticity, improving the impact toughness of the welded joint and reducing the risk of brittle fracture.

[0135] Please refer to Figure 3 and Figure 5 In one embodiment, the remelted layer 17 is provided around the weld 16.

[0136] In this embodiment, after welding is completed, the laser beam is controlled to move around the edge of the weld 16, which can remelt all edges of the weld 16, effectively cleaning the welding slag generated during the welding process and reducing the risk of welding slag entering the injection hole 18 and flowing to the next process.

[0137] Please refer to Figure 5 The first workpiece is set as a pole post 11, the second workpiece is set as a current collector 12, the battery cell 10 is provided with a liquid injection hole 18 that passes through the pole post 11 and the current collector 12, and the weld 16 extends circumferentially along at least part of the liquid injection hole 18.

[0138] In this embodiment, the terminal post 11 and current collector 12 of the battery cell 10 are connected by welding. The terminal post 11 and current collector 12 are provided with interconnected injection holes 18. The injection holes 18 are used to inject electrolyte into the battery. The welding area of ​​the terminal post 11 and current collector 12 surrounds the injection hole 18, which can form a closed-loop weld 16 or an open-loop weld 16.

[0139] Optionally, in the overlapping direction of the pole post 11 and the collector plate 12, the thickness of the pole post 11 is greater than the thickness of the collector plate 12. Optionally, the material of both the collector plate 12 and the pole post 11 can be set to, but is not limited to, aluminum.

[0140] In one embodiment, the width of the remelted layer 17 located on the side of the weld 16 near the injection hole 18 is not less than the width of the remelted layer 17 located on the side of the weld 16 away from the injection hole 18.

[0141] In this embodiment, the welding area can be positioned as far away from the injection hole 18 as possible to reduce the risk of weld slag falling into the injection hole 18. This arrangement provides a larger blank area on the side of the weld 16 closest to the injection hole 18. During the remelting process after welding, the laser beam is controlled to perform multiple remelting processes on the edge of the weld 16 closest to the injection hole 18. Two, three, or more remelting operations can be performed, the number of which can be determined based on the distance between the weld 16 and the injection hole 18. Multiple remelting operations can be performed without affecting the helium inspection area and the injection hole 18. This arrangement effectively cleans the weld slag on the side of the weld 16 closest to the injection hole 18, reducing the risk of weld slag falling into the injection hole 18.

[0142] Please refer to Figure 6 In one embodiment, along the width direction of the weld 16, the weld 16 includes a first fusion zone 162 and a second fusion zone 163.

[0143] The grain size in the first fusion zone 162 is smaller than that in the second fusion zone 163. This arrangement, through the reciprocating oscillating welding method, forms relatively fine equiaxed grains in a portion of the weld 16. The fine grain structure has higher strength and better plasticity, which is beneficial to improving the impact toughness of the welded joint and reducing the risk of brittle fracture.

[0144] Please refer to Figure 6 In one embodiment, the grain orientation in the first fusion zone 162 is different from that in the second fusion zone 163; with this arrangement, the grains are spatially distributed in a multi-directional manner, and the grain boundaries are tortuous, which can hinder the straight propagation of cracks and improve the toughness of the weld 16.

[0145] Please refer to Figure 3 This application proposes a battery welding method for welding a first workpiece and a second workpiece in a battery cell 10, the battery welding method comprising the following steps:

[0146] The laser beam is controlled to weld a first welding trajectory 101 and a second welding trajectory 102 at the overlap position of the first workpiece and the second workpiece to form a weld 16. The first welding trajectory 101 includes a first welding segment 1011 located at the arc initiation segment 164 and a second welding segment 1012 located at the end segment 161. The second welding trajectory 102 coincides with at least one of the first welding segment 1011 and the second welding segment 1012.

[0147] In this application, during the welding of the first and second workpieces of the battery cell 10, the laser beam moves along the first welding trajectory 101 and the second welding trajectory 102, respectively, and the second welding trajectory 102 coincides with at least one of the first welding segment 1011 in the starting region and the second welding segment 1012 in the ending region of the first welding trajectory 101. For example, the second welding trajectory 102 may include a third welding segment 1021 that coincides with the first welding segment 1011, or it may include a fourth welding segment 1022 that coincides with the second welding segment 1012. That is, when welding the first and second workpieces, two welding processes are performed at the arc-starting segment 164 and / or the ending segment 161 of the weld 16; with this arrangement, the slag generated during the first welding will re-form a molten pool through remelting during the second welding, which can avoid the generation and residue of slag at the arc-starting point.

[0148] In one embodiment, the step of controlling the laser beam to weld the first welding trajectory 101 includes:

[0149] The laser beam is controlled to move along the length of the preset weld 16 and oscillate back and forth along the width of the weld 16 to weld the overlapping area of ​​the first workpiece and the second workpiece to form the weld 16.

[0150] In this embodiment, during the welding of the first and second workpieces, the laser beam forms a first welding trajectory 101 for oscillating welding. The laser beam moves along the length of the expected weld 16 and simultaneously oscillates along the width of the expected weld 16, causing the first welding trajectory 101 to form a broken line or sinusoidal trajectory. This configuration ensures a uniform distribution of laser energy in the welding area, reducing molten pool velocity and temperature gradient, improving energy distribution uniformity, thereby enhancing welding stability, reducing pinholes and bursts, and lowering the risk of undercut and slag defects in the weld 16. Furthermore, the oscillating laser beam along the width of the weld 16 ensures that the weld 16 meets the requirements for surface weld width and effective weld width. Optionally, in the welding process outside the positive electrode, the surface weld width of the weld 16 is required to be less than 1.5 mm to avoid interference with the helium detection area. The effective weld width is required to be greater than 0.4 mm to ensure sufficient flow area.

[0151] Optionally, the movement of the laser beam can be controlled by controlling the swing angle of the galvanometer in the laser generator, or by controlling the movement of the entire laser generator.

[0152] Please refer to Figure 3 In one embodiment, the first welding trajectory 101 is set as a sinusoidal oscillating trajectory.

[0153] In this embodiment, the welding trajectory of the laser beam in the welding area is similar to a sine wave or a sawtooth shape, which can maximize the effective weld width under the same surface weld width and effective weld depth, so that the weld 16 meets the requirements of surface weld width and effective weld width.

[0154] Please refer to Figure 3 In one embodiment, the second welding trajectory 102 includes a third welding segment 1021 located in the arc-starting segment 164, and the end of the third welding segment 1021 is connected to the starting position of the first welding trajectory 101; the laser beam moves sequentially along the third welding segment 1021 and the first welding trajectory 101; the arc-starting position of the third welding segment 1021 is located in the molten pool area formed when welding along the first welding trajectory 101.

[0155] In this embodiment, the laser beam begins welding from the third welding segment 1021 of the second welding trajectory 102. When welding reaches the end of the third welding segment 1021, it is at the starting position of the first welding trajectory 101, and then continues welding along the first welding trajectory 101. The arc-starting position of the third welding segment 1021 is located within the first welding trajectory 101, so that the laser beam will pass through the third welding segment 1021 as it moves along the first welding trajectory 101. This allows the weld slag generated at the arc-starting position of the third welding segment 1021 to be remelted to form a molten pool, thus avoiding the generation and residue of weld slag at the arc-starting point.

[0156] In one embodiment, the laser energy of the laser beam at the arc-starting position of the third welding segment 1021 does not exceed 50% of the laser energy of the laser beam during its movement along the first welding trajectory 101.

[0157] In this embodiment, the laser energy of the laser beam as it moves along the first welding trajectory 101 is set such that the laser beam can penetrate the first workpiece but not the second workpiece, and can be used to weld the first and second workpieces together. The laser energy at the arc-starting position of the third welding segment 1021 is relatively small; at this point, the laser energy may or may not penetrate the first workpiece, without limitation. This setting, by reducing the laser energy at the arc-starting position, can avoid or reduce the generation of weld slag at the arc-starting position, and prevent processing defects such as pinholes and bursts at the arc-starting position.

[0158] In one embodiment, the laser energy gradually increases as the laser beam moves along the third welding section 1021.

[0159] In this embodiment, the laser energy of the laser beam gradually increases. When the laser beam moves to the end of the third welding segment 1021, i.e., the starting position of the first welding trajectory 101, the energy of the laser beam just reaches the welding energy range that can penetrate the first workpiece but will not penetrate the second workpiece. Alternatively, before the laser beam reaches the end of the third welding segment 1021, the laser energy reaches the welding energy range that can penetrate the first workpiece but will not penetrate the second workpiece. This ensures that the laser beam can meet the welding requirements when moving along the first welding trajectory 101, and avoids generating excessive weld slag during the movement of the laser beam along the third welding segment 1021.

[0160] In one embodiment, the amplitude of the laser beam oscillating back and forth along the width direction of the weld 16 is not less than the ratio between the welding speed and the oscillation frequency of the laser beam.

[0161] In this embodiment, during the welding process of the laser beam onto the electrode 11 and the collector plate 12, the first welding trajectory 101 of the laser beam is a triangular wave or a sine wave trajectory. The amplitude of the laser beam's reciprocating oscillation is the distance between the crest and trough of the toothed wave or sine wave. The welding speed of the laser beam is the speed at which the laser beam moves along the length of the weld 16, and the oscillation frequency of the laser beam is the number of reciprocating oscillations per unit time. Ensuring that the oscillation amplitude of the laser beam is not less than the ratio between the welding speed and the oscillation frequency guarantees that the final weld 16 meets the requirements for surface weld width and effective weld width.

[0162] Please refer to Figure 3 In one embodiment, the second welding trajectory 102 further includes a fourth welding segment 1022 located at the termination segment 161. The step of controlling the laser beam to weld the first welding trajectory 101 and the second welding trajectory 102 at the overlap position of the first workpiece and the second workpiece respectively includes:

[0163] The laser beam is controlled to weld along the first welding trajectory 101; the laser beam is controlled to move from the end of the first welding trajectory 101 along the fourth welding segment 1022 to perform re-welding above the second welding segment 1012.

[0164] In this embodiment, after the laser beam moves to the end of the first welding trajectory 101, the laser beam is controlled to move along the fourth welding segment 1022 to extend the existence time of the molten pool in the finishing arc crater, so that the molten pool at the welding end position has a longer time to solidify, avoiding the metal shrinkage not in time when the molten pool solidifies, ensuring that the metal can fully shrink back to fill the middle area of ​​the weld 16, reducing the risk of problems such as undercut and pinhole bursts, and also helping to reduce the generation of welding slag.

[0165] Please refer to Figure 3 In one embodiment, the fourth welding segment 1022 has a spiral trajectory.

[0166] In this embodiment, the fourth welding segment 1022 of the laser beam forms a spiral trajectory, so that the laser beam moves simultaneously along the length and width directions of the weld 16. This can make the energy distribution in the end-of-weld crater area uniform during the re-welding process, and is conducive to extending the solidification time of the molten pool, reducing the risk of problems such as undercut and pinhole bursts, and also helps to reduce the generation of welding slag and improve the welding effect.

[0167] In one embodiment, the laser energy of the laser beam is gradually reduced during the reflow process.

[0168] In this embodiment, when controlling the laser beam to perform re-welding in the end region of weld 16, the power of the laser beam is gradually reduced to avoid excessive laser energy during the re-welding process, which would burn through the end arc crater. This also helps to reduce or avoid the generation of welding slag at the end arc crater.

[0169] Please refer to Figure 3 In one embodiment, after controlling the laser beam to move along the length direction of a preset weld 16 and oscillate back and forth along the width direction of the weld 16 to weld the overlapping area of ​​the first workpiece and the second workpiece to form the weld 16, the method further includes:

[0170] The laser beam is controlled to remelt the surface of the pole post 11 at the edge of the weld 16.

[0171] In this embodiment, after the weld 16 is formed, the edge of the weld 16 is remelted. The generated weld slag can be remelted to form a molten pool, avoiding the generation and residue of weld slag. The laser energy used in the remelting process is relatively small, so that the thickness of the remelted layer 17 formed by remelting does not exceed the thickness of the pole post 11, thereby avoiding burning through the manifold 12.

[0172] Please refer to Figure 3 In one embodiment, the remelting trajectory 103 of the laser beam is arranged around the weld 16.

[0173] In this embodiment, after welding is completed, the laser beam is controlled to move around the edge of the weld 16, which can remelt all edges of the weld 16, effectively cleaning the welding slag generated during the welding process and reducing the risk of welding slag entering the injection hole 18 and flowing to the next process.

[0174] Please refer to Figure 3 In one embodiment, the battery cell 10 is provided with a liquid injection hole 18 that passes through the first workpiece and the second workpiece, and the weld 16 is arranged around at least part of the circumference of the liquid injection hole 18; the laser beam performs multiple remelting processes on the edge of the weld 16 near the liquid injection hole 18.

[0175] In the battery cell 10, the electrolyte injection holes 18 on the electrode post 11 and the current collector 12 are used to inject electrolyte into the battery. The welding area of ​​the electrode post 11 and the current collector 12 surrounds the electrolyte injection hole 18, which can form a closed-loop weld 16 or an open-loop weld 16. In this embodiment, during the remelting process after welding, the laser beam is controlled to remelt the edge of the weld 16 near the electrolyte injection hole 18 multiple times. Two, three, or more remeltings can be performed. The number of remeltings can be determined according to the distance between the weld 16 and the electrolyte injection hole 18. Multiple remeltings can be performed without affecting the helium detection area and the electrolyte injection hole 18. This setting can effectively clean the welding slag on the side of the weld 16 near the electrolyte injection hole 18, reducing the risk of welding slag falling into the electrolyte injection hole 18.

[0176] In one embodiment, before the step of controlling the laser beam to move along the length direction of a preset weld 16 and oscillate back and forth along the width direction of the weld 16 to weld the overlapping area of ​​the first workpiece and the second workpiece to form the weld 16, the method further includes:

[0177] Step S01: Remove impurities from the surface of the electrode post 11 by negative pressure dust removal.

[0178] During the welding process of the electrode post 11 and the collector plate 12, since the laser first acts on the electrode post 11, if there is dust, water stains or other impurities on the surface of the electrode post 11, pinholes and welding slag are likely to occur. By cleaning the impurities on the surface of the electrode post 11 before welding, particulate impurities or other impurities can be avoided on the surface of the electrode post 11, maintaining the cleanliness of the electrode post 11 surface and reducing the welding slag generated during the welding process.

[0179] A negative pressure dust collection device can be installed on the production line. The electrode post 11 is cleaned by the negative pressure dust collection device without direct contact with the surface of the electrode post 11. The impurities on the surface of the electrode post 11 are sucked away and will not fly to the welding position or other positions on the production line, reducing the impact on the production line and production process.

[0180] In one embodiment, the dust extraction duct is inclined upward relative to the horizontal direction.

[0181] In this embodiment, the dust extraction duct is inclined upward from the end near the welding area to the end away from the welding area, so that the airflow driven during the dust removal process flows smoothly from the welding area into the dust extraction duct, which is conducive to improving the dust removal effect, and the dust extraction duct does not occupy a lot of space in the vertical direction.

[0182] Please refer to Figure 3 and Figure 5 In one embodiment, the weld 16 extends at least part of the circumferential direction along the injection hole 18 of the battery cell 10, the injection hole 18 is blocked by a sealing structure 3000, the sealing structure 3000 is provided with a protective gas channel, and the outlet of the protective gas channel is arranged facing the welding area; the battery welding method also includes blowing protective gas into the welding area during the welding process.

[0183] In this embodiment, before welding, the injection hole 18 is sealed by the sealing structure 3000. This protects the injection hole 18 and its surrounding area, and also prevents welding slag from falling directly into the injection hole 18. Simultaneously, the sealing structure 3000 also includes a shielding gas channel. During welding, the shielding gas is blown towards the welding area through this channel, preventing oxidation or nitriding of the weld 16, reducing spatter and pinholes, and ensuring uniform cooling and solidification of the molten pool, thus improving the welding effect.

[0184] Please refer to Figure 7 and Figure 8 In one embodiment, the sealing structure 3000 includes a pressure block 3001 and a plug 3002. The pressure block 3001 is disposed opposite to the electrode post 11 and has a vent 3005 disposed opposite to the injection hole 18. The surface of the pressure block 3001 facing away from the electrode post 11 has a venting groove 3006 communicating with the vent 3005. The plug 3002 includes a mounting plate 3003 and a sealing part 3004. The mounting plate 3003 is disposed on the pressure block 3002. On the side opposite to the pole post 11, the sealing part 3004 passes through the vent 3005 and is inserted into the injection hole 18 to seal the injection hole 18. The sealing part 3004 and the edge of the vent 3005 are spaced apart, and an air outlet gap is formed between the sealing part 3004 and the edge of the vent 3005. The air guide groove 3006 and the air outlet gap are connected to form a protective gas channel. The protective gas passes through the air guide groove 3006 and the air outlet gap in sequence to be blown toward the welding area.

[0185] In this embodiment, the sealing structure 3000 includes a pressure block 3001 and a plug 3002. The pressure block 3001 is disposed opposite to the pole post 11, and the plug 3002 passes through the pressure plate to better seal the injection hole 18. The pressure block 3001 can play a certain shielding role, preventing welding slag or other impurities from entering the welding area, and can also ensure that the protective gas is accurately blown to the welding area, and can also reduce the leakage of protective gas.

[0186] Please refer to Figure 8 In one embodiment, the pressure block 3001 is provided with at least two air guide grooves 3006, which are arranged circumferentially along the air vent 3005.

[0187] This configuration helps to increase the amount of air entering the protective gas channel and ensures that the protective gas is evenly distributed within the channel, thereby improving the blowing effect.

[0188] Please refer to Figure 8 In one embodiment, the air guide groove 3006 is tangent to the air vent 3005.

[0189] In this embodiment, when the protective gas flows from the gas guide groove 3006 into the gas vent 3005, it can flow out along the edge of the gas vent 3005 to form a ring blowing effect, which can blow uniform protective gas into the welding area; and it can avoid mutual blowing with the airflow flowing into the gas vent 3005 from other gas guide grooves 3006, thereby reducing mutual interference of airflow and avoiding a decrease in airflow velocity, ensuring the blowing effect and welding effect.

[0190] In one embodiment, the pressure block 3001 and the plug 3002 are separately configured.

[0191] This configuration allows for easy cleaning or replacement of the plug 3002 without disassembling the entire sealing structure 3000; only the plug 3002 needs to be removed, thus improving ease of use.

[0192] Optionally, a cleaning device for the plug 3002 can be installed in the production line for automatic cleaning of the plug 3002. The cleaning method of the plug 3002 cleaning device can be, but is not limited to, at least one method such as vacuum cleaning, air blowing cleaning, or wiping cleaning, and is not limited here.

[0193] Please refer to Figure 9This application also proposes a battery device 100, including the battery cell 10 in any of the foregoing embodiments, the specific structure of which refers to the above embodiments. The battery device 100 may include one or more battery cell assemblies for providing voltage and capacity, and can serve as a power source or power system for an electrical device. The battery cell assembly may include multiple battery cells 10, which are connected in series, parallel, or mixed connections via a busbar.

[0194] In some embodiments, the battery cell assembly is typically formed by arranging a plurality of battery cells 10.

[0195] As an example, a battery cell assembly can be a battery module, which is formed by arranging and fixing multiple battery cells 10 together to form an independent module. As an example, a battery module can be formed by bundling multiple battery cells 10 together with cable ties.

[0196] In some embodiments, the battery device 100 may be a battery pack, which includes a housing 20 and one or more battery cell assemblies housed within the housing 20. As an example, the battery cell assembly may be a battery module, which can be housed within the housing 20 by securing the battery module to the housing 20. Alternatively, the battery cell assembly may be housed within the housing 20 by directly securing multiple battery cells 10 to the housing 20.

[0197] Since the battery device 100 proposed in this application can adopt all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, and will not be described in detail here.

[0198] This application also proposes an electrical device, including a battery cell 10 or a battery device 100 as described in any of the foregoing embodiments. The specific structures of the battery cell 10 and the battery device 100 are as described in the above embodiments. Since the electrical device proposed in this application can adopt all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, and will not be described in detail here.

[0199] For ease of explanation, the following embodiments will be described using a vehicle 1000 as an example of an electrical device according to an embodiment of this application.

[0200] Please refer to Figure 10 , Figure 9 This is a structural schematic diagram of a vehicle 1000 provided in some embodiments of this application.

[0201] Vehicle 1000 can be a rail train, a fuel-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. A battery device 100 is installed inside vehicle 1000, and the battery can be located at the bottom, front, or rear of vehicle 1000. The battery can be used to power vehicle 1000; for example, battery device 100 can serve as the operating power source for vehicle 1000. Vehicle 1000 may also include a controller 200 and a motor 300. Controller 200 controls the battery device 100 to supply power to motor 300, for example, to meet the power needs of vehicle 1000 during starting, navigation, and driving. In some embodiments of this application, battery device 100 can also serve as the driving power source for vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for vehicle 1000, and can also be used to power electrical appliances on vehicle 1000.

[0202] The above description is merely an exemplary embodiment of this application and does not limit the patent scope of this application. Any equivalent structural transformations made based on the technical concept of this application and the contents of the specification and drawings of this application, or direct / indirect applications in other related technical fields, are included within the patent protection scope of this application.

Claims

1. A battery cell, characterized in that, The battery cell includes a first workpiece and a second workpiece, the first workpiece being located above the second workpiece, and the overlapping area of ​​the first workpiece and the second workpiece being welded together to form a weld. The first welding trajectory of the battery cell extends along the length direction of the weld and reciprocates along the width direction of the weld. The first welding trajectory includes a first welding segment located at the arc initiation section and a second welding segment located at the end section. The second welding trajectory of the battery cell coincides with at least one of the first welding segment and the second welding segment.

2. The battery cell as described in claim 1, characterized in that, The second welding trajectory includes a third welding segment, the weld includes an arc-starting segment, the arc-starting segment includes the first welding segment and the third welding segment located below the first welding segment, the starting end of the third welding segment coincides with the first welding trajectory, and the ending end of the third welding segment is located at the same end of the weld as the starting end of the first welding segment.

3. The battery cell as described in claim 2, characterized in that, The depth of the arc-starting segment increases progressively from the end of the first welding segment to the end of the second welding segment.

4. The battery cell as described in claim 1, characterized in that, The second welding trajectory includes a fourth welding segment, and the weld includes a finishing segment. The finishing segment includes the second welding segment and the fourth welding segment located above the second welding segment. The end of the second welding segment and the beginning of the fourth welding segment are located at the same end of the weld.

5. The battery cell as described in claim 4, characterized in that, The fourth welding section is arranged in a spiral shape.

6. The battery cell as described in claim 1, characterized in that, The first workpiece has a remelting layer on the side opposite to the second workpiece, and the remelting layer is formed at the edge of the weld.

7. The battery cell as described in claim 6, characterized in that, The grain size in the remelted layer is smaller than the grain size in the weld.

8. The battery cell as described in claim 6, characterized in that, The remelted layer is provided around the weld.

9. The battery cell according to any one of claims 1 to 8, characterized in that, The first workpiece is configured as an electrode post, the second workpiece is configured as a current collector, the battery cell is provided with a liquid injection hole that passes through the electrode post and the current collector, and the weld extends circumferentially along at least part of the liquid injection hole.

10. The battery cell as described in claim 9, characterized in that, When a remelting layer is provided, the width of the remelting layer on the side of the weld near the injection hole is not less than the width of the remelting layer on the side of the weld away from the injection hole.

11. The battery cell according to any one of claims 1 to 8, characterized in that, Along the width direction of the weld, the weld includes a first fusion zone and a second fusion zone; Wherein, the grain size in the first fusion region is smaller than the grain size in the second fusion region; And / or, the grain orientation in the first fusion region is different from the grain orientation in the second fusion region.

12. A battery welding method for welding battery cells as described in any one of claims 1 to 11, characterized in that, The battery welding method includes the following steps: The laser beam is controlled to weld a first welding trajectory and a second welding trajectory at the overlap position of the first workpiece and the second workpiece to form a weld. The first welding trajectory includes a first welding segment located at the arc initiation section and a second welding segment located at the end section. The second welding trajectory coincides with at least one of the first welding segment and the second welding segment. The step of controlling the laser beam to weld the first welding trajectory includes: The laser beam is controlled to move along the length of the preset weld and oscillate back and forth along the width of the weld to perform welding on the overlapping area of ​​the first workpiece and the second workpiece.

13. The battery welding method as described in claim 12, characterized in that, The first welding trajectory is set as a sinusoidal oscillating trajectory.

14. The battery welding method as described in claim 12, characterized in that, The second welding trajectory includes a third welding segment located at the arc initiation segment, and the end of the third welding segment is connected to the starting position of the first welding trajectory; The laser beam moves sequentially along the third welding segment and the first welding trajectory, and the second welding trajectory is located in the molten pool region formed when welding along the first welding trajectory.

15. The battery welding method as described in claim 14, characterized in that, The laser energy of the laser beam at the arc-starting position of the third welding segment does not exceed 50% of the laser energy of the laser beam during its movement along the first welding trajectory; And / or, the laser energy gradually increases as the laser beam moves along the third welding segment.

16. The battery welding method as described in claim 12, characterized in that, The amplitude of the laser beam oscillating back and forth along the width of the weld is not less than the ratio between the welding speed and the oscillation frequency of the laser beam.

17. The battery welding method as described in claim 12, characterized in that, The second welding trajectory further includes a fourth welding segment located at the end section. The step of controlling the laser beam to weld the first welding trajectory and the second welding trajectory at the overlap position of the first workpiece and the second workpiece respectively includes: Control the laser beam to weld along the first welding trajectory; The laser beam is controlled to move from the end of the first welding trajectory along the fourth welding segment to perform a re-welding process above the second welding segment.

18. The battery welding method as described in claim 17, characterized in that, The fourth welding segment has a spiral trajectory; And / or, during the reflow process, the laser energy of the laser beam gradually decreases.

19. The battery welding method according to any one of claims 12 to 18, characterized in that, After the step of controlling the laser beam to weld the first welding trajectory and the second welding trajectory at the overlap position of the first workpiece and the second workpiece respectively, the method further includes: The laser beam is controlled to remelt the surface of the first workpiece facing away from the second workpiece at the edge region of the weld.

20. The battery welding method as described in claim 19, characterized in that, The remelting trajectory of the laser beam is set around the weld; And / or, the battery cell is provided with a liquid injection hole that passes through the first workpiece and the second workpiece, and the laser beam performs multiple remelting processes on the edge of the weld near the liquid injection hole.

21. The battery welding method according to any one of claims 12 to 18, characterized in that, Before the step of controlling the laser beam to move along the length of the preset weld seam, move along the width of the weld seam in a first direction, and oscillate back and forth in a second direction to weld the overlapping area of ​​the first workpiece and the second workpiece, the method further includes: Impurities on the electrode surface are cleaned by negative pressure dust removal.

22. The battery welding method as described in claim 21, characterized in that, The dust extraction duct is set at an upward angle relative to the horizontal direction.

23. The battery welding method according to any one of claims 12 to 18, characterized in that, The battery cell is provided with a liquid injection hole that passes through the first workpiece and the second workpiece. The weld extends circumferentially along at least part of the liquid injection hole. The liquid injection hole is blocked by a sealing structure. A protective gas channel is provided in the sealing structure. The outlet of the protective gas channel is oriented towards the welding area. The battery welding method also includes blowing protective gas into the welding area during the welding process.

24. The battery welding method as described in claim 23, characterized in that, The sealing structure includes: A pressure block, wherein the pressure block is disposed opposite to the battery and has a vent port disposed opposite to the liquid injection hole; the surface of the pressure block opposite to the electrode post has a vent groove communicating with the vent port; and The plug includes a mounting plate and a sealing part. The mounting plate is located on the side of the pressure block facing away from the pole post. The sealing part passes through the vent to block the injection hole. The sealing part is spaced apart from the edge of the vent, and an air outlet gap is formed between the sealing part and the edge of the vent. The gas guide groove and the gas outlet gap are connected to form the protective gas channel, and the protective gas passes through the gas guide groove and the gas outlet gap in sequence to be blown toward the welding area.

25. The battery welding method as described in claim 24, characterized in that, The pressure block is provided with at least two air guide grooves, and the at least two air guide grooves are arranged circumferentially along the air inlet; And / or, the air guide groove is tangent to the air inlet; And / or, the pressure block and the plug are separate components.

26. A battery device, characterized in that, Includes the battery cell as described in any one of claims 1 to 11.

27. An electrical appliance, characterized in that, Includes the battery cell as described in any one of claims 1 to 11 or the battery device as described in claim 26.

Images