Aluminum row welding method and battery module

Abstract

The invention discloses an aluminum row welding method and a battery module, and the aluminum row welding method comprises the following steps: providing a battery which comprises a pole; an aluminum bar is provided, the aluminum bar comprises a working face and an appearance face which are opposite, a welding hole penetrating through the working face and the appearance face is formed in the aluminum bar, the diameter of the welding hole on the working face is a first diameter D1, the diameter of the welding hole on the appearance face is a second diameter D0, and D1 is smaller than D0; and fitting the working surface with the pole, heating and melting the hole wall of the welding hole, and welding the aluminum bar with the battery. Compared with the prior art, the aluminum row is not prone to collapse in the welding process, and the welding seam quality is good.

Description

Technical Field

[0001] The present invention relates to the technical field of battery processing, and in particular to an aluminum bar welding method and a battery module. Background Art

[0002] Battery packs and battery modules usually include multiple single cells, which are usually connected in series or in parallel or both through aluminum bars. Welding is one of the main ways to connect the aluminum bar with the pole of the single cell. Specifically, a welding hole is opened on the aluminum bar to expose part of the pole, and the hole wall is melted by laser. After cooling, the aluminum bar and the pole are welded.

[0003] In the process of partial melting and subsequent solidification of the existing aluminum bar, there is a non-negligible flow of the aluminum bar material. On the one hand, this brings uncertainty to the specific shape of the weld. On the other hand, the molten metal flowing to the surface of the pole forms oxidized slag in the process of contact with the air, which greatly deteriorates the welding effect of the weld. Summary of the invention

[0004] An object of the present invention is to provide an aluminum bar welding method and a battery module, which are intended to solve the technical problem of poor quality of welds formed by aluminum bar welding.

[0005] In order to achieve the above object, the present invention provides a solution: an aluminum bar welding method, the aluminum bar welding method comprising the following steps:

[0006] Providing a battery, the battery including a terminal;

[0007] An aluminum bar is provided, the aluminum bar comprises a working surface and an appearance surface opposite to each other, a welding hole penetrating the working surface and the appearance surface is opened on the aluminum bar, a diameter of the welding hole on the working surface is a first diameter D1, a diameter of the welding hole on the appearance surface is a second diameter D0, and D1<D0;

[0008] The working surface is fitted with the pole, the pole is partially exposed to the welding hole, the hole wall of the welding hole is heated and melted, and the aluminum busbar is welded to the battery.

[0009] In some embodiments of the present application, heating and melting the hole wall of the welding hole includes:

[0010] Provide a heat source; make the heat source scan and heat along the hole wall of the welding hole, the scanning path includes multiple first paths and multiple second paths, the first path points from the working surface to the appearance surface, and the second path points from the appearance surface to the working surface, and the multiple first paths and the second paths are alternately cycled to achieve melting of the welding hole.

[0011] In some embodiments of the present application, a plurality of first paths and second paths are performed alternately and cyclically, including: an included angle between an extension direction of the first path and an extension direction of the weld is α, 60°≤α<90°.

[0012] The angle between the hole wall of the welding hole and the working surface is β, α+β<140°.

[0013] In some embodiments of the present application, multiple first paths and second paths are performed alternately and cyclically, including:

[0014] When the heat source scans along the first path, the heat source works to heat and melt the hole wall of the welding hole. When the heat source scans along the second path, the heat source stops heating.

[0015] In some embodiments of the present application, scanning and heating the heat source along the hole wall of the welding hole includes:

[0016] The scanning speed of the heat source is between 5 m / min and 20 m / min; and / or the welding speed is between 1 m / min and 5 m / min.

[0017] In some embodiments of the present application, a heat source is provided, comprising:

[0018] The working power of the heat source is P, 500W≤P≤4000W.

[0019] In some embodiments of the present application, an aluminum bar is provided, comprising:

[0020] Provide aluminum sheet;

[0021] Conical drill bits are available;

[0022] Use a conical drill bit to open welding holes on the aluminum plate to obtain the aluminum row.

[0023] In some embodiments of the present application, a tapered drill bit is provided, including: a taper of the tapered drill bit is between 0.5 and 2.

[0024] In some embodiments of the present application, an aluminum bar is provided, comprising:

[0025] 15mm≤D1≤20mm; and / or, the thickness of the aluminum bar is L, 2mm≤L≤3mm; and / or, the angle between the hole wall of the welding hole and the working surface is β, 30°<β<60°.

[0026] To achieve the above object, another solution provided by the present invention is: a battery module, the battery module includes batteries and aluminum bars, and the batteries and the aluminum bars are welded together by any of the aluminum bar welding methods described above.

[0027] The beneficial effects of the present invention are:

[0028] The aluminum bar welding method of the present invention provides an aluminum bar in the step of providing an aluminum bar, wherein the aluminum bar comprises a relative working surface and an appearance surface, and a welding hole penetrating the working surface and the appearance surface is provided on the aluminum bar, wherein the diameter of the welding hole on the working surface is a first diameter D1, and the diameter of the welding hole on the appearance surface is a second diameter D2, wherein D1<D2, i.e., the cross-sectional size of the welding hole increases from the working surface to the appearance surface. When the hole wall of the welding hole is melted and has a certain fluidity, because the hole wall of the welding hole is inclined and the diameter of the welding hole at one end of the working surface is smaller, i.e., the hole wall is thicker, it has a stability similar to that of a dam, and it is difficult for the molten metal to flow significantly before solidification, so that during the entire welding process, the risk of oxidation of the connection surface between the pole and the aluminum bar is smaller, and the weld shape is stable.

[0029] The hole wall of the welding hole in the prior art will collapse after melting, which causes the hole wall of the welding hole to contact the air under high temperature, and the inclusions will be rolled into the lower end of the weld as the collapse progresses. The inclusions will be retained between the weld and the pole, which will cause the inclusions to be retained between the weld and the pole, and this part of the inclusions will seriously deteriorate the performance of the weld. However, the aluminum bar processing method of the present application does not have the phenomenon of collapse. Therefore, it is only necessary to clean the area where the working surface contacts the pole. In the subsequent welding process, the bonding area is kept in contact throughout the process, and air is difficult to invade. The risk of oxidation of the connection surface is small. Even if welding is performed in an air environment, welding quality similar to gas shielded welding can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0031] Figure 1 This is the overall schematic diagram of the aluminum row in the prior art:

[0032] Figure 2 is along Figure 1 Schematic diagram of the cross section along the AA line;

[0033] Figure 3 1 is a schematic flow chart of an aluminum bar welding method provided by an embodiment of the present invention;

[0034] Figure 4 This is an overall schematic diagram of the aluminum bar provided in an embodiment of the present invention:

[0035] Figure 5 is along Figure 4 Schematic diagram of the cross section of the middle BB line;

[0036] Figure 6 Schematic diagram of the matching relationship between the aluminum bar and the battery in an embodiment of the present invention;

[0037] Figure 7 is a flow chart of step S300 of the aluminum bar welding method provided in an embodiment of the present invention;

[0038] Figure 8 Schematic diagram of the heat source moving path of step S300 of the aluminum bar welding method provided in an embodiment of the present invention;

[0039] Fig. 9 1 is a flow chart of step S200 of the aluminum bar welding method provided in an embodiment of the present invention;

[0040] Fig.10 is a schematic diagram of the aluminum bar structure in step S200 of the aluminum bar welding method provided in an embodiment of the present invention;

[0041] Fig.11 It is a flow chart of step S200 of the aluminum bar welding method provided in another embodiment of the present invention.

[0042] Description of Figure Numbers:

[0043] 10. Battery; 11. Pole; 20. Aluminum bar; 2a. Working surface; 2b. Appearance surface; 21. Welding hole; 211. First hole; 212. Second hole; 213. Third hole; 31. First path; 32. Second path. DETAILED DESCRIPTION

[0044] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0045] See also Figure 1 and Figure 2 As shown, Figure 1 This is the overall schematic diagram of the aluminum row in the prior art: Figure 2 is along Figure 1 Schematic diagram of the cross section along line AA.

[0046] At present, the welding of aluminum bars and poles is commonly achieved by laser welding. Unlike brazing, which relies on the filling of brazing material to make welds, the formation of laser welding welds relies on the cladding of the workpiece material itself. In the existing aluminum bar welding process, the welding hole is usually perpendicular to the surface of the aluminum bar. Therefore, the entire laser welding process is usually accompanied by the overflow of molten metal and the collapse of the welding hole wall. With the collapse of the hole wall, the surface layer of molten metal that was originally in contact with the air is drawn between the weld and the pole. This part of the surface layer is inevitably severely oxidized at high temperature, which leads to the deterioration of the quality of the weld and the pole, and has adverse effects on the connection strength and conductivity.

[0047] See also Figures 3 to 6 As shown, Figure 3 1 is a schematic flow chart of an aluminum bar welding method provided by an embodiment of the present invention; Figure 4 This is an overall schematic diagram of the aluminum bar 20 provided in an embodiment of the present invention: Figure 5 is along Figure 4 Schematic diagram of the cross section of the middle BB line; Figure 6 Schematic diagram of the matching relationship between the aluminum bar 20 and the battery 10 according to an embodiment of the present invention.

[0048] In order to solve the above technical problems, the present invention provides an aluminum bar welding method, which comprises the following steps:

[0049] S100 , providing a battery 10 , wherein the battery 10 includes a pole 11 .

[0050] S200, provide an aluminum bar 20, the aluminum bar 20 includes a relative working surface 2a and an appearance surface 2b, and a welding hole 21 penetrating the working surface 2a and the appearance surface 2b is opened on the aluminum bar 20, the diameter of the welding hole 21 on the working surface 2a is a first diameter D1, and the diameter of the welding hole 21 on the appearance surface 2b is a second diameter D0, D1<D0.

[0051] S300 , the working surface 2 a is fitted to the pole 11 , the pole 11 is partially exposed to the welding hole 21 , the hole wall of the welding hole 21 is heated and melted, and the aluminum bus 20 is welded to the battery 10 .

[0052] At the welding angle, that is, when the aluminum bar 20 is placed above the battery 10, with the working surface 2a at the bottom and the appearance surface 2b at the top, the cross-sectional area of ​​the welding hole 21 of the aluminum bar 20 provided in step S200 of the present invention decreases from top to bottom, and the cross-sectional shape of the hole wall of the welding hole 21 on the plane passing through its axis is similar to a dam. In step S300, the aluminum bar 20 is welded to the battery 10. From a microscopic perspective, the upper hole wall is blocked by the lower hole wall during the downward flow after melting, and it is difficult to have obvious displacement in the short time before solidification; from a macroscopic perspective, the surface of the welding hole 21 of the aluminum bar 20 and a certain depth area under the surface are melted and solidified to form a weld. Near the welding hole 21, part of the aluminum bar 20 on the working surface 2a is adhered and fixed to the pole 11, realizing the welding of the aluminum bar 20 and the battery 10.

[0053] Compared with the prior art, the shape of the aluminum bar 20 of this embodiment, especially the shape of the welding hole 21, does not change significantly before and after the welding process. The shape of the hole wall of the welding hole 21 before welding is the surface shape of the weld after welding, so the shape of the weld is stable and controllable.

[0054] From the perspective of weld performance, during the melting of the aluminum bar 20, the metal layer on the surface of the molten pool comes into direct contact with the air at high temperature, which will undoubtedly produce serious oxidized slag. In the flat welding state, the surface layer of the weld formed by the solidification of this part of the degraded molten pool will be polished or knocked off to ensure the purity of the weld composition. During the welding process of the aluminum bar 20, the welding method of the prior art will cause the hole wall of the welding hole 21 to collapse. As the collapse proceeds, the oxide scale and inclusions on the surface layer will be rolled into the lower end of the weld and eventually stay between the weld and the pole 11. These inclusions will seriously degrade the performance of the weld. However, in this embodiment, it is only necessary to clean the area where the working surface 2a contacts the pole 11. In the subsequent welding process, the working surface 2a and the area where the pole 11 is about to be connected are kept in contact throughout the process, air is difficult to intrude, and the risk of oxidation of the connection surface is relatively small. Even if welding is performed in an air environment, welding quality similar to that of gas shielded welding can be achieved.

[0055] It should be noted that the cross-sections of most welding holes 21 perpendicular to their axes are circular, so in this embodiment, the cross-sectional dimensions of the welding holes 21 are defined by diameter, and for a small number of special-shaped holes, the diameter here should be understood as the longest section length that can be obtained inside the cross-sectional figure. For example, in one technical solution, the edge shape of the welding hole 21 on the working surface 2a is a square, and the diagonal length of the square is the first diameter; for another example, in another technical solution, the edge shape of the welding hole 21 on the appearance surface 2b is an ellipse, and the long axis length of the ellipse is the second diameter.

[0056] In addition, in this embodiment, only the case where the aluminum bar 20 is melted is analyzed. In some processing techniques, in addition to the hole wall of the welding hole 21 being melted, the heat source will further sink, causing the surface of the pole 11 to melt to a certain extent. This difference in process will expand the molten pool and enhance the connection between the weld and the pole 11. The technical effect of this embodiment still holds. Specifically, in the processing technique where the molten pool spans the aluminum bar 20 and the pole 11, if the hole wall of the welding hole 21 collapses, although no obvious inclusion layer will be formed between the weld and the pole 11, the collapsed oxide slag will still be mixed into the molten pool, and the inclusions will be dispersed in the molten pool, resulting in the deterioration of the weld. However, the shape of the aluminum bar 20 provided in this embodiment makes it difficult for collapse to occur, so the composition of the molten pool is relatively pure and the weld quality is good.

[0057] Please also read Figure 7 and Figure 8 As shown, Figure 7 is a flow chart of step S300 of the aluminum bar welding method provided in an embodiment of the present invention; Figure 8 It is a schematic diagram of the heat source moving path of step S300 of the aluminum bar welding method provided in an embodiment of the present invention.

[0058] In some embodiments of the present application, heating and melting the hole wall of the welding hole 21 includes:

[0059] S301, providing a heat source; illustratively, the heat source may be a laser, an electric arc, etc.

[0060] S302, scanning and heating the heat source along the first path 31 of the wall of the welding hole 21, wherein the first path 31 is directed from the working surface 2a to the appearance surface 2b.

[0061] S303, scanning and heating the heat source along the second path 32 of the hole wall of the welding hole 21, wherein the second path 32 is directed from the appearance surface 2b to the working surface 2a.

[0062] S304 , looping through step S302 and step S303 until the welding hole 21 is melted.

[0063] Alternating and cycling multiple first paths 31 and second paths 32 can increase the energy density along the extension direction of the weld. Compared with simply increasing the power of the heat source or slowing down the movement speed of the heat source, the zigzag heating achieved by alternating along the first path 31 and the second path 32 can alleviate the heat enrichment caused by the energy increase and avoid overburning of the molten pool.

[0064] It should be noted that the scanning path of the heat source including the first path 31 and the second path 32 should not be understood as "the scanning path of the heat source only includes the first path 31 and the second path 32". The first path 31 and the second path 32 can be connected in sequence, or can be arranged at intervals with the third path, the fourth path, etc. interspersed therebetween. Moreover, the heat source can heat the hole wall of the welding hole 21 along the first path 31 and the second path 32 throughout the entire process, or can input energy to the welding hole 21 intermittently.

[0065] Exemplarily, the scanning speed of the heat source is between 5 m / min and 20 m / min.

[0066] Too fast a scanning speed can lead to technical failures such as insufficient heating and failure to form a molten pool. The scanning speed of the heat source is between 5m / min and 20m / min. The scanning speed can be increased as much as possible while ensuring good formation of the molten pool, thereby improving productivity.

[0067] Exemplarily, the welding speed is between 1 m / min and 5 m / min.

[0068] Too high a welding speed will increase the control cost of automatic processing, and may even cause the heat source to completely melt the entire wall of the welding hole 21, while the initially melted area has not yet solidified. This end-to-end molten pool will increase the risk of the wall of the welding hole 21 collapsing, and the metal that is still in a molten state will be heated again and easily cause overburning. A welding speed between 1m / min and 5m / min is a relatively safe welding speed range under the premise of ensuring processing efficiency.

[0069] Exemplarily, the operating power of the heat source is P, 500W≤P≤4000W.

[0070] Too small a welding power will prolong the formation time of the molten pool, resulting in low production efficiency. Too large a welding power will cause the aluminum bar 20 to be easily overburned. The power range of 500W≤P≤4000W is a safe range where overburning is not likely to occur while ensuring processing efficiency. It can provide better protection for the aluminum bar 20, especially the starting area of ​​the weld.

[0071] Further, in step S303, the angle between the extension direction of the first path 31 and the extension direction of the weld is α, 60°≤α<90°.

[0072] The angle between the extension direction of the first path 31 and the extension direction of the weld is an acute angle, that is, in step S302, the heat source moves obliquely upward in the direction of gravity when scanning along the first path 31, and there is still a solid area below the newly melted area, which can further curb the sliding trend of the welding hole 21 and maintain the stability of the weld shape.

[0073] Furthermore, the angle between the hole wall of the welding hole 21 and the working surface 2a is β, and α+β<140°.

[0074] As mentioned above, the first path 31 is tilted so that there is still a solid area below the newly melted area of ​​the heat source. Therefore, when the tilt of the hole wall of the welding hole 21 increases, that is, β decreases, the tilt of the first path 31 can be appropriately reduced, that is, α increases. Setting α+β<140° can more conveniently balance the tilt of the first path 31 and the hole wall of the welding hole 21.

[0075] Optionally, in step S300 , when the heat source scans along the first path 31 , the heat source works to heat and melt the hole wall of the welding hole 21 , and when the heat source scans along the second path 32 , the heat source stops heating.

[0076] Since the input of heat requires a medium, during the welding process, the particle flow that transports heat will also blow the molten pool so that the metal in the molten pool has a tendency to flow, which is particularly obvious in laser welding. In this embodiment, the heat source works only when it is along the first path 31, that is, scanning upward, which makes the molten pool have a tendency to move slightly upward while the heat is input, especially the oxide scale on the surface of the molten pool, which is difficult to fall off under the blowing of the particle flow. Even if the shape of the welding hole 21 changes slightly, this part of the oxide scale is not easy to be rolled into the weld and the pole 11, so the composition purity of the weld is further guaranteed.

[0077] Please also read Fig. 9 and Fig.10 As shown, Fig. 9 1 is a flow chart of step S200 of the aluminum bar welding method provided in an embodiment of the present invention; Fig.10 It is a structural schematic diagram of the aluminum bar 20 in step S200 of the aluminum bar welding method provided in an embodiment of the present invention.

[0078] In some embodiments of the present application, step S200 includes:

[0079] S201. Provide aluminum plate.

[0080] S202, providing a first drill bit with a diameter of D1, and opening a first hole 211 penetrating the exterior surface 2b and the working surface 2a in the aluminum plate.

[0081] S203, providing a second drill bit with a diameter of D2, and drilling a second hole 212 with a depth of l 2 from the exterior surface 2b, the second hole 212 being coaxial with the first hole 211, and D2>D1.

[0082] S204, provide a third drill bit with a diameter of D3, and open a second hole 212 with a depth of l 3 from the appearance surface 2b. The third hole 213 is coaxial with the first hole 211, D3>D2, and the first hole 211, the second hole 212, and the third hole 213 are interconnected to form a welding hole 21.

[0083] This embodiment provides an optional processing method for the aluminum bar 20. For the welding holes 21 with larger apertures, this processing method performs the cutting work in steps, which can avoid chipping of the cutting edge or excessive wear of the cutting tool caused by excessive cutting.

[0084] Further, the first hole 211, the second hole 212 and the third hole 213 satisfy: l 3*(D2-D1)>(l 2-l 3)(D3-D2).

[0085] In the aluminum bar 20 processed in this embodiment, the slope of the welding hole 21 on the side close to the working surface 2a is relatively gentle, and the slope on the side close to the appearance surface 2b is relatively gentle, which makes it more difficult for the side of the welding hole 21 close to the working surface 2a to collapse while the apertures on both sides of the welding hole 21 remain unchanged. Even if a part of the welding hole 21 collapses, the collapsed metal is difficult to reach the working surface 2a, so as not to affect the performance of the weld. In addition, compared with the common configuration of D3-D2=D2-D1, l 3*(D2-D1)>(l 2-l 3)(D3-D2) makes the cutting amount of the second drill bit and the third drill bit similar, avoiding excessive cutting amount of the third drill bit and extra wear.

[0086] Please also read Fig.11 As shown, Fig.11 It is a flow chart of step S200 of the aluminum bar welding method provided in another embodiment of the present invention.

[0087] In some other embodiments of the present application, step S200 includes:

[0088] S201. Provide aluminum plate.

[0089] S202: Provide a tapered drill bit.

[0090] S203, using a conical drill bit to open a welding hole 21 on the aluminum plate to obtain an aluminum row 20.

[0091] For the aluminum bars 20 with smaller welding holes 21 , the processing method provided in this embodiment can be used for efficient batch processing to provide the aluminum bars 20 .

[0092] Furthermore, the taper of the tapered drill bit in step S202 is between 0.5 and 2.

[0093] The larger the angle between the hole wall of the welding hole 21 and the working surface 2a, the greater the risk of the hole wall sliding and collapsing. On the contrary, the smaller the angle between the hole wall of the welding hole 21 and the working surface 2a, the greater the energy consumption required to penetrate the hole wall. Experimental verification shows that the welding hole 21 processed by a tapered drill with a taper between 0.5 and 2 can reduce the consumption of welding energy as much as possible without sliding and collapsing.

[0094] In some embodiments of the present application, in step S202, 15 mm ≤ D1 ≤ 20 mm.

[0095] If D1 is too small, the welding strength will be insufficient and the resistance at the connection will be too large. If D1 is too large, the welding time required for each aluminum row 20 will be too long. 15mm≤D1≤20mm is the only option that can shorten the welding time while ensuring functionality.

[0096] In some embodiments of the present application, in step S202 , the thickness of the aluminum bar 20 is L, 2 mm ≤ L ≤ 3 mm.

[0097] The thicker the aluminum bar 20 is, the stronger its current load capacity is, but the worse its weld penetration is. 2mm≤L≤3mm can meet the load requirements of the aluminum bar 20 in general scenarios, and weld penetration can be achieved without additional improvements to the welding equipment.

[0098] In some embodiments of the present application, in step S202, the angle between the hole wall of the welding hole 21 and the working surface 2a is β, 30°<β<60°.

[0099] If β is too large, the risk of collapse of the welding hole 21 during welding will increase. If β is too small, the weld penetration of the welding hole 21 will deteriorate. 30°<β<60° is an angle selection that is not prone to collapse while ensuring weld penetration.

[0100] In order to solve the above technical problems, the present invention further discloses a battery module, which includes a battery 10 and an aluminum bar 20, and the battery 10 and the aluminum bar 20 are welded together by the aluminum bar welding method disclosed in any of the above embodiments.

[0101] Because the processing of the battery module uses the above-mentioned aluminum bar welding method, the battery module also has the above-mentioned technical effects, that is, the weld shape is stable, the connection strength of the aluminum bar 20 and the battery 10 is high, and the current load capacity is strong. It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiment of the present invention are only used to explain the relative position relationship and movement of various components in a certain posture. If the specific posture changes, the directional indication will also change accordingly.

[0102] It should also be noted that when an element is referred to as being "fixed on" or "disposed on" another element, it may be directly on the other element or there may be an intermediate element at the same time. When an element is referred to as being "connected to" another element, it may be directly connected to the other element or may be indirectly connected to the other element through an intermediate element.

[0103] In addition, the descriptions of "first", "second", etc. in the present invention are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0104] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the design concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A method for welding an aluminum bar, characterized in that: include: Providing a battery, the battery comprising a terminal; An aluminum bar is provided, the aluminum bar comprising a working surface and an appearance surface opposite to each other, a welding hole penetrating the working surface and the appearance surface is opened on the aluminum bar, the diameter of the welding hole on the working surface is a first diameter D1, the diameter of the welding hole on the appearance surface is a second diameter D0, and D1<D0; The working surface is fitted with the pole, the pole is partially exposed to the welding hole, the hole wall of the welding hole is heated and melted, and the aluminum row is welded to the battery.

2. The aluminum bar welding method according to claim 1, characterized in that: The step of heating and melting the hole wall of the welding hole comprises: Provide a heat source; The heat source is made to scan and heat along the hole wall of the welding hole, and the scanning path includes a plurality of first paths and a plurality of second paths, wherein the first path points from the working surface to the appearance surface, and the second path points from the appearance surface to the working surface, and the plurality of the first paths and the second paths are alternately cycled to achieve melting of the welding hole.

3. The aluminum bar welding method according to claim 2, characterized in that: The alternating cycle of performing a plurality of the first paths and the second paths comprises: The included angle between the extending direction of the first path and the extending direction of the weld is α, 60°≤α<90°.

4. The aluminum bar welding method according to claim 3, characterized in that: The included angle between the hole wall of the welding hole and the working surface is β, and α+β<140°.

5. The aluminum bar welding method according to claim 2, characterized in that: The alternating cycle of performing a plurality of the first paths and the second paths comprises: When the heat source scans along the first path, the heat source works to heat and melt the hole wall of the welding hole. When the heat source scans along the second path, the heat source stops heating.

6. The aluminum bar welding method according to claim 2, characterized in that: The step of scanning and heating the heat source along the hole wall of the welding hole comprises: The scanning speed of the heat source is between 5m / min and 20m / min; and / or The welding speed is between 1 m / min and 5 m / min.

7. The aluminum bar welding method according to claim 2, characterized in that: The providing of a heat source comprises: The working power of the heat source is P, 500W≤P≤4000W.

8. The aluminum bar welding method according to claim 1, characterized in that: The aluminum bar provided comprises: Provide aluminum sheet; Conical drill bits are available; The welding holes are opened on the aluminum plate using the conical drill bit to obtain the aluminum bar.

9. The aluminum bar welding method according to claim 8, characterized in that: The conical drill bit provided comprises: The taper of the conical drill bit is between 0.5 and 2.

10. The aluminum bar welding method according to any one of claims 1 to 9, characterized in that: The aluminum bar provided comprises: 15mm≤D1≤20mm; and / or The thickness of the aluminum bar is L, 2mm≤L≤3mm; and / or The included angle between the hole wall of the welding hole and the working surface is β, 30°<β<60°.

11. A battery module, characterized in that: The battery module comprises a battery and an aluminum bar, and the battery and the aluminum bar are welded together by the aluminum bar welding method according to any one of claims 1 to 10.

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