Welding equipment, welding method, battery manufacturing equipment, and automobile manufacturing equipment

Abstract

The present invention provides a welding apparatus and a welding method capable of improving welding efficiency in a battery manufacturing process, and a battery manufacturing apparatus and an automobile manufacturing apparatus including the welding apparatus. The welding apparatus according to one aspect of the present invention includes a laser irradiation unit configured to irradiate a laser, and a laser output control unit configured to control the laser irradiation unit to irradiate a peak power laser and a base power laser to a welding portion.

Description

[Technical Field]

[0001] The present invention relates to welding apparatus, welding method, battery manufacturing apparatus, and automobile manufacturing apparatus, and more particularly to welding apparatus and welding method capable of improving welding efficiency, and battery manufacturing apparatus and automobile manufacturing apparatus including such welding apparatus.

[0002] This application claims priority under Korean Patent Application No. 10-2022-0084677 filed on 8 July 2022 and Korean Patent Application No. 10-2022-0136866 filed on 21 October 2022, and all content disclosed in the specifications and drawings of said applications is incorporated into this application. [Background technology]

[0003] Generally, welding equipment includes a laser light source and optical components such as a focusing lens to increase the energy density of the laser emitted from the laser light source.

[0004] Such welding equipment can be used, for example, to join components that make up a battery module. As an example, a battery module can be constructed by superimposing or stacking multiple battery cells (e.g., secondary batteries) in themselves or mounted on cartridges to create a dense structure that provides high voltage and high current, and then electrically connecting these.

[0005] In such battery modules, good welding is crucial for constructing a stable battery module structure, specifically between the module case containing the battery cells and the end plate, which is configured to cover the busbars electrically connecting the battery cells. As an example, a welding device can be configured to weld keyholes in the welded area (e.g., between the module case and the end plate).

[0006] On the other hand, in conventional welding equipment, welding between the module case and the end plate is performed using the CW (Continuous Wave) laser welding method. In this type of CW laser welding, the accumulation of heat input energy in the weld area may increase with welding time. In this case, there is a problem that welding defects may occur in the weld area due to the excessive accumulation of heat input energy in the weld area. [Overview of the project] [Problems that the invention aims to solve]

[0007] The present invention was made to solve the above-mentioned problems, and aims to provide a welding apparatus and welding method that can improve welding efficiency, as well as a battery manufacturing apparatus and an automobile manufacturing apparatus including such a welding apparatus.

[0008] However, the technical problems that this invention aims to solve are not limited to those described above, and other problems not mentioned will be clearly understood by those skilled in the art from the description of the invention below. [Means for solving the problem]

[0009] A welding apparatus according to one aspect of the present invention includes a laser irradiation unit configured to irradiate a laser, and a laser output control unit configured to control the laser irradiation unit to irradiate a peak output laser and a base output laser onto the welding area.

[0010] Preferably, the laser output control unit may be configured to control the laser irradiation unit so that the weld area remains in a liquid state.

[0011] Preferably, the laser output control unit may be configured to control the laser irradiation unit so that the peak output laser and the base output laser are alternately irradiated onto the weld.

[0012] Preferably, the peak-power laser may have an output capable of forming a keyhole in the weld, and the base-power laser may have an output that does not form a penetration in the weld.

[0013] Preferably, the base output laser may have an output capable of maintaining the weld in a liquid state.

[0014] Preferably, the laser output control unit may be configured to control the pulse width of the base output laser.

[0015] Preferably, the laser output control unit may be configured to control the pulse frequency of the base output laser.

[0016] Preferably, the laser output control unit may be configured to control the output of the base output laser.

[0017] Preferably, the welding apparatus further includes an inspection unit configured to inspect the welding condition at the weld after welding is completed by the welding apparatus, and the laser output control unit may be configured to control the output of the base output laser in accordance with welding condition inspection information provided by the inspection unit.

[0018] Preferably, the welding apparatus further includes an inspection unit configured to inspect the welding condition at the weld during welding by the welding apparatus, and the laser output control unit may be configured to control the output of the base output laser in accordance with welding condition inspection information provided by the inspection unit.

[0019] A welding method according to one aspect of the present invention includes the steps of irradiating the welding area with a peak-power laser and irradiating the welding area with a base-power laser.

[0020] A battery manufacturing apparatus according to one aspect of the present invention may include a welding apparatus according to one aspect of the present invention as described above.

[0021] An automobile manufacturing apparatus according to an aspect of the present invention can include a welding apparatus according to an aspect of the present invention as described above.

Advantages of the Invention

[0022] According to an embodiment of the present invention, compared with the prior art, it is possible to prevent excessive accumulation of heat input energy at the welding portion to minimize welding defects, and to maintain the liquid state of the welding portion during the welding process to increase the laser absorption rate of the welding portion, thereby maintaining the same welding speed and welding productivity as the prior art.

[0023] Furthermore, according to various embodiments of the present invention, various other additional effects can be achieved. Such various effects of the present invention will be described in detail in each embodiment, or the description will be omitted for effects that can be easily understood by those skilled in the art.

[0024] The following drawings attached to this specification illustrate preferred embodiments of the present invention and serve to further understand the technical idea of the present invention together with the detailed description of the invention. Therefore, the present invention should not be construed as being limited only to the matters described in the drawings.

Brief Description of the Drawings

[0025] [Figure 1] It is a diagram showing a welding apparatus according to an embodiment of the present invention. [Figure 2] It is a diagram showing a change in laser output by the welding apparatus of FIG. 1. [Figure 3] It is a diagram showing the generation of a keyhole in the welding portion due to a change in laser output in FIG. 2. [Figure 4] It is a diagram showing the difference in energy accumulation amount in the welding portion according to the laser oscillation mode. [[ID=�5]] [Figure 5] It is a diagram showing a change in laser output due to the oscillation of a conventional pulsed laser. [Figure 6] It is a diagram showing the laser absorption rate of pure aluminum due to temperature change. [[ID=四十]] <0000 [Figure 7]This figure shows the simulation results for the boundary values ​​between heat conduction welding and keyhole welding. [Figure 8] This figure illustrates the change in laser pulse width controlled by the laser output control unit in the welding apparatus shown in Figure 1. [Figure 9] This figure illustrates the change in the laser pulse frequency caused by the control of the laser output control unit in the welding apparatus shown in Figure 1. [Figure 10] This figure illustrates the change in laser output controlled by the laser output control unit installed in the welding apparatus shown in Figure 1. [Figure 11] This figure shows another control method for the laser using the welding apparatus of the present invention. [Figure 12] This figure shows another control method for the laser using the welding apparatus of the present invention. [Modes for carrying out the invention]

[0026] Preferred embodiments of the present invention will be described in detail below with reference to the attached drawings. Prior to this, terms and words used in this specification and in the claims shall not be interpreted in their usual and dictionary sense, but rather in a sense and concept appropriate to the technical idea of ​​the present invention, in accordance with the principle that the inventor himself may appropriately define the concept of terms in order to best describe the invention.

[0027] Figure 1 shows a welding apparatus 10 according to one embodiment of the present invention, Figure 2 shows the change in laser output by the welding apparatus 10 of Figure 1, and Figure 3 shows the generation of a keyhole K in the welded part W due to the change in laser output in Figure 2.

[0028] Referring to Figures 1 to 3, the welding apparatus 10 according to one embodiment of the present invention may be configured to perform welding at the welding area W by irradiating it with a laser.

[0029] The welded joint W may, for example, represent a joint between components of a battery module (not shown). In this case, the battery module may contain at least one secondary battery.

[0030] For example, welding between components of a battery module can be performed using a known keyhole welding method. More specifically, the welding apparatus 10 can, but is not limited to, welding between a module case (not shown) and an end plate (not shown) of a battery module for housing a secondary battery.

[0031] For example, the module case and end plate may be made of aluminum. That is, the welded joint W may be made of aluminum. However, the welded joint W is not limited to aluminum, and may also include aluminum and its alloys.

[0032] As shown in Figure 1, the welding apparatus 10 may include a laser irradiation unit 100 and a laser output control unit 200. A portion of the laser irradiation unit 100 may be housed within the housing H. The laser output control unit 200 may be provided on the outer surface of the housing H.

[0033] The laser irradiation unit 100 may be configured in the form of an optical system to irradiate with a laser. Although not shown in detail, the laser may be irradiated onto W in the form of a beam.

[0034] In one embodiment, the laser irradiation unit 100 may include a laser light source (not shown) and a focusing lens (not shown).

[0035] The aforementioned laser light source is capable of generating the aforementioned laser.

[0036] The aforementioned focusing lens can improve the energy density of the laser generated by the laser light source. In this case, the laser can pass through the focusing lens and irradiate the welded area W.

[0037] As shown in Figure 2, the laser output control unit 200 can control the laser irradiation unit 100 to irradiate the weld W with a laser of peak power and a laser of base power. Here, the base power may be an output with a lower magnitude than the peak power. In other words, the laser output control unit 200 can control the laser irradiation unit 100 to irradiate the same weld W with outputs of different magnitudes. As an example, the laser output control unit 200 may include a processor.

[0038] Furthermore, as shown in Figure 3, the laser irradiation unit 100 can irradiate the weld W with a peak power laser and a base power laser under the control of the laser power control unit 200 so that two or more keyholes K are superimposed on a single weld line. Here, the keyholes K are formed using energy multiple reflection and absorption in the focal section of the laser beam and can be formed in a roughly keyhole shape. At this time, the housing H can be moved by a separate moving stage (not shown) so that the laser irradiation unit 100 moves along a single weld line while irradiating the weld W with the laser.

[0039] Furthermore, after welding is completed on one welding line, the housing H containing the laser irradiation unit 100 may move to other welding lines on the welding area W. Subsequently, the laser irradiation unit 100 can repeat the above operation for other welding lines on the welding area W under the control of the laser output control unit 200.

[0040] As shown in Figure 4(a), in the conventional CW (Continuous Wave) laser welding method, excess energy accumulates in the weld as the laser irradiation time to the weld increases. In this case, the area shown in the graph in Figure 4(a) represents the heat input energy accumulated in the weld due to the laser irradiation time.

[0041] In this case, excessive melting of the weld metal (the portion of metal that melts and solidifies during welding) can occur in the weld, potentially leading to a localized melt-down phenomenon where the weld metal detaches.

[0042] On the other hand, referring to Figure 4(b), in the laser welding method using the welding apparatus 10 of the present invention, the laser irradiation unit 100 irradiates the welding area W with a peak output laser and a base output laser. As a result, compared to the conventional CW laser welding method, the accumulation of heat input energy in the welding area W in accordance with the laser irradiation time occurs relatively slowly. This laser welding method using the welding apparatus 10 of the present invention is a method of irradiating a laser in a form that combines the CW laser welding method and the PW (Pulse Wave) laser welding method, and can be called a quasi-pulse laser welding method.

[0043] In other words, the welding method using the welding apparatus 10 of the present invention includes the steps of irradiating the welding area W with a peak-power laser and irradiating the welding area W with a base-power laser.

[0044] When irradiating the weld area W with a laser in a quasi-pulse mode in this way, a base-power laser with a relatively lower output than the peak-power laser can be irradiated onto the weld area W during the interval in which the peak-power laser is irradiated onto the weld area W. Therefore, in the case of the welding apparatus 10 of the present invention, welding defects can be minimized by preventing excessive accumulation of heat input energy in the weld area W.

[0045] Figure 5 shows the change in laser output due to the oscillation of a conventional pulsed laser, and Figure 6 shows the laser absorption rate of pure aluminum due to temperature changes.

[0046] Referring to Figure 5, in the conventional PW laser welding method, the pulsed laser is irradiated onto the welding area in a manner that periodically turns on and off (On / Off).

[0047] In the PW laser welding method described above, as shown by the arrow in Figure 5(a), during the section where the pulsed laser is oscillating, the weld area melts due to the irradiation of the pulsed laser, changing from a solid state to a liquid state. At this time, it can be said that a keyhole is formed in the weld area.

[0048] On the other hand, as shown by the arrow in Figure 5(b), in the section where the pulsed laser is off, there is no energy supplied to the weld, so it can be said that the weld changes back from a liquid state to a solid state.

[0049] Referring to Figure 6, when a pulsed laser at a constant wavelength (e.g., 1.06 μm) is oscillated with pure aluminum, the laser absorption rate in the solid state of the weld may be at least 3.8 times lower than that in the liquid state, relative to the melting point temperature of pure aluminum.

[0050] Therefore, as shown by the arrow in Figure 5(c), in the section where the pulsed laser oscillation is turned on again, the weld, which had turned into a solid state in the section shown in Figure 5(b), may need to be melted again. As a result, the laser absorption rate in the solid state of the weld is relatively lower than that in the liquid state of the weld, reducing the melting efficiency. This leads to the problem of a slower welding speed.

[0051] On the other hand, the laser output control unit 200 provided in the welding apparatus 10 of the present invention may have a configuration that controls the laser irradiation unit 100 so that the welding area W maintains a liquid state.

[0052] In other words, in the welding apparatus 10 of the present invention, the laser output control unit 200 controls the laser irradiation unit 100 to sequentially irradiate the welding area W with the peak output laser and the base output laser, thereby guiding the welding area W to maintain a liquid state without changing from a liquid state to a solid state. For this reason, in the welding apparatus 10 of the present invention, unlike the conventional PW laser welding method, it is possible to prevent the occurrence of a period in which the laser oscillation is completely off.

[0053] Specifically, referring to the part indicated by the arrow in Figure 2(a), the laser irradiation unit 100 can irradiate the weld W with a peak-power laser under the control of the laser output control unit 200. As a result, the weld W can melt and change from a solid state to a liquid state. At this time, a keyhole K may be formed in the weld W, as shown in Figure 3(a).

[0054] Furthermore, referring to the part indicated by the arrow in Figure 2(b), the laser irradiation unit 100 can irradiate the weld W with a base-power laser under the control of the laser output control unit 200. In this way, by irradiating the weld W with a base-power laser having an output relatively lower than the peak output, it is possible to suppress the weld W from changing back from a liquid state to a solid state.

[0055] In this case, further penetration may not occur in the weld W, as shown in Figure 3(b). This will be explained in more detail in the related explanations below.

[0056] Furthermore, referring to the portion indicated by the arrow in Figure 2(c), the laser irradiation unit 100 can irradiate the weld W with a peak-power laser again under the control of the laser output control unit 200. At this time, since the liquid state of the weld W is maintained by the irradiation of the base-power laser in Figure 2(b), the formation of a keyhole K in the weld W is made easier when the peak-power laser is irradiated as in Figure 2(c). On the other hand, a keyhole K may be formed in the weld W such that at least a portion of it overlaps with the keyhole K generated in Figure 3(a), as shown in Figure 3(c).

[0057] According to this embodiment, compared to the conventional method, excessive accumulation of heat input energy in the weld W is prevented, minimizing welding defects. Furthermore, by maintaining the liquid state of the weld W during the welding process and increasing the laser absorption rate of the weld W, the same welding speed and welding productivity as the conventional method can be maintained.

[0058] Referring again to Figure 2, the laser output control unit 200 can control the laser irradiation unit 100 so that the peak output laser and the base output laser are alternately irradiated onto the weld W.

[0059] Specifically, the laser irradiation unit 100 can alternately and continuously irradiate the weld area W with a peak output laser and a base output laser under the control of the laser output control unit 200.

[0060] This allows for less energy to be applied to the weld area W compared to conventional methods, while ensuring that there are no periods where the laser irradiation is turned off, thereby more reliably maintaining the liquid state of the weld area W during the welding process.

[0061] Figure 7 shows the simulation results for the boundary values ​​between heat conduction welding and keyhole welding.

[0062] Referring to Figure 7, in the welding apparatus 10 of the present invention, the peak output laser may have an output capable of forming a keyhole K in the weld W. Furthermore, the base output laser may have an output that does not form penetration in the weld W. That is, as shown in Figure 7, the base output laser may have an output that does not form a penetration depth in the weld W. Therefore, as shown in Figure 7, the base output laser may have an output that does not form a penetration depth in the weld W, and thus it can be said that it has an output that does not form penetration in the weld W. On the other hand, if the output of the laser irradiated from the laser irradiation unit 100 is less than the output value required to form a keyhole K, the weld W may be welded in the form of heat conduction welding.

[0063] As an example, the peak output of the welding apparatus 10 of the present invention is 2.2 kW / mm². 2 The above can be set. The peak output value may be the minimum value at which a keyhole K can be formed in the weld W containing aluminum material. Furthermore, the base output of the welding apparatus 10 of the present invention is approximately 0.92 kW / mm². 2 ~1.42kW / mm 2 It can be set within the range.

[0064] In other words, in the welding apparatus 10 of the present invention, even with a low-power base output laser that does not cause penetration of the weld W in the section where the base output laser is irradiated onto the weld W, the weld W can be maintained in a liquid state. This is because, as shown in Figure 7, the base output (e.g., 0.92 kW / mm²) 2 ~1.42kW / mm 2 When a laser within the specified output range is irradiated onto the weld W, it can be confirmed that no penetration depth occurs in the weld W, or that the penetration depth of the weld W is extremely small.

[0065] Therefore, the penetration depth of the keyhole K formed in the laser irradiation section of Figure 3(c) may be approximately the same as the penetration depth of the keyhole K formed in the laser irradiation section of Figure 3(a).

[0066] According to this embodiment, by alternately irradiating the weld W with a peak power laser and a base power laser, it is possible to achieve the same welding speed as in the conventional method while preventing penetration from forming in the weld W in the section where the base power laser is irradiated, thereby preventing excessive penetration in a specific area of ​​the weld W. This minimizes welding defects caused by burn-through.

[0067] In particular, the base output laser may have an output that allows the welded area W to maintain a liquid state.

[0068] In other words, the base power laser may have the minimum power output required to maintain the weld W in a liquid state during the process of alternately irradiating the weld W with the peak power laser and the base power laser.

[0069] Figure 8 is an illustrative diagram showing the change in the laser pulse width controlled by the laser output control unit 200 provided in the welding apparatus 10 of Figure 1. In this case, Figure 8(a) shows the state before the pulse width of the base output laser is adjusted, and Figure 8(b) shows the state after the pulse width of the base output laser is adjusted.

[0070] Referring to Figure 8, the laser output control unit 200 of the welding apparatus 10 of the present invention may be configured to control the pulse width of the base output laser.

[0071] In one embodiment of the present invention, if the weld W includes a material that is more sensitive to the laser (e.g., a metallic material with a lower melting point than aluminum), the exemplified power range (0.92 kW / mm²) 2 ~1.42kW / mm 2 In the section where the base output laser (within the output range) is irradiated onto the weld W, there is a possibility that penetration may occur in the weld W.

[0072] In this case, the laser output control unit 200 can prevent penetration into the weld W in the section where the base output laser is irradiated onto the weld W by adjusting the pulse width of the base output laser according to the characteristics of the weld W. For example, if the weld W contains a material that is more sensitive to the laser, the laser output control unit 200 can adjust the pulse width of the base output laser to be smaller, as shown by the arrows and diagonal lines in Figure 8(b).

[0073] According to this embodiment, by controlling the pulse width of the base output laser according to the characteristics of the weld W, excessive penetration in a specific area of ​​the weld W can be prevented. This minimizes welding defects caused by burn-through.

[0074] Figure 9 is an illustrative diagram showing the change in the laser pulse frequency controlled by the laser output control unit 200 provided in the welding apparatus 10 of Figure 1. In this case, Figure 9(a) shows the state before the pulse frequency of the base output laser is adjusted, and Figure 9(b) shows the state after the pulse frequency of the base output laser is adjusted.

[0075] Referring to Figure 9, the laser output control unit 200 may be configured to control the pulse frequency of the base output laser.

[0076] As described above, the laser irradiation unit 100 can irradiate the weld area W with a peak output laser and a base output laser under the control of the laser output control unit 200, as shown in Figure 3, so that two or more keyholes K are superimposed on a single welding line.

[0077] In the welding apparatus 10 of the present invention, when adjusting the pulse frequency of the base output laser, the overlapping area between at least two keyholes K at the welding part W can change. At this time, since the laser irradiation unit 100 irradiates the welding part W alternately with the peak output laser and the base output laser, when adjusting the pulse frequency of the base output laser, the pulse frequency of the peak output laser can also be adjusted together.

[0078] As an example, as shown in (b) of FIG. 9, the laser output control unit 200 can adjust so that the pulse frequency of the base output laser increases. At this time, the pulse frequency of the peak output laser can also be adjusted to increase together.

[0079] According to such an embodiment, when increasing the pulse frequency of the base output laser, the overlapping area of the keyholes K at the welding part W can be increased, so that welding at the welding part W can be performed more stably. Further, when the welding part at the welding part W is small, while increasing the welding speed by increasing the pulse frequency of the base output laser, excessive accumulation of heat input energy at the welding part W can be minimized.

[0080] FIG. 10 is a diagram exemplarily showing changes in the laser output under the control of the laser output control unit 200 provided in the welding apparatus 10 of FIG. At this time, (a) of FIG. 10 shows the state before the output of the base output laser is adjusted, and (b) of FIG. 10 shows the state after the output of the base output laser is adjusted.

[0081] Referring to FIG. 10, the laser output control unit 200 can be configured to control the output of the base output laser.

[0082] In one embodiment of the present invention, when the welding part W contains a material that reacts more sensitively to the laser (for example, a metal material with a lower melting point than aluminum, etc.), the exemplified output range (0.92 kW / mm 2 ~1.42 kW / mm 2In the section where the base output laser (within the output range) is irradiated onto the weld W, there is a possibility that penetration may occur in the weld W.

[0083] In this case, the laser output control unit 200 can prevent penetration into the weld W in the section where the base output laser is irradiated onto the weld W by adjusting the output of the base output laser according to the characteristics of the weld W. For example, if the weld W contains a material that is more sensitive to the laser, the laser output control unit 200 can adjust the output of the base output laser to be lower, as shown by the arrow and diagonal lines in Figure 10(b).

[0084] According to this embodiment, by controlling the output of the base output laser according to the characteristics of the weld W, excessive penetration in a specific area of ​​the weld W can be prevented. This minimizes welding defects caused by burn-through.

[0085] Referring to Figure 1, the welding apparatus 10 of the present invention may further include an inspection unit 300.

[0086] The inspection unit 300 may be configured to inspect the welding condition of the welded joint W after welding is completed by the welding apparatus 10. For example, the inspection unit 300 may include a processor, a camera (e.g., an infrared camera), an X-ray transmission device, etc. The inspection unit 300 may also be provided on the outer surface of the housing H described above.

[0087] For example, if the inspection unit 300 detects that excessive penetration has occurred in a specific area of ​​the weld W after welding has been completed by the welding device 10, the inspection unit 300 can transmit such welding condition inspection information to the laser output control unit 200.

[0088] In this case, the laser output control unit 200 may be configured to control the output of the base output laser according to the welding condition inspection information provided by the inspection unit 300. That is, the laser output control unit 200 can control the output of the base output laser so that welding defects and other problems do not occur when the welding apparatus 10 performs welding again.

[0089] On the other hand, the laser output control unit 200 can also be configured to control the pulse width or pulse frequency of the base output laser according to the welding condition inspection information provided by the inspection unit 300.

[0090] On the other hand, the inspection unit 300 can also be configured to inspect the welding condition at the weld W during welding by the welding device 10.

[0091] For example, if the inspection unit 300 detects that excessive penetration has occurred in a specific area of ​​the weld W during welding by the welding device 10, the inspection unit 300 can transmit such welding condition inspection information to the laser output control unit 200.

[0092] In this case, the laser output control unit 200 may be configured to control the output of the base output laser according to the welding condition inspection information provided by the inspection unit 300. That is, the laser output control unit 200 can control the output of the base output laser during welding by the welding apparatus 10 to prevent further welding defects from occurring.

[0093] On the other hand, the laser output control unit 200 can also be configured to control the pulse width or pulse frequency of the base output laser according to the welding condition inspection information provided by the inspection unit 300.

[0094] Figures 11 and 12 show other control methods for the laser using the welding apparatus 10 of the present invention.

[0095] In the present invention, since the base power laser is irradiated onto the weld W during the interval in which the peak power laser is irradiated onto the weld W, the liquid state of the weld W can be maintained throughout the entire welding process.

[0096] In the case of the welding apparatus 10 of the present invention, as shown in Figure 11, the laser output control unit 200 can also control the irradiation of the laser by the laser irradiation unit 100 so that the output of the peak output laser and the base output laser decreases over time. Alternatively, in the case of the welding apparatus 10 of the present invention, as shown in Figure 12, the laser output control unit 200 can also control the irradiation of the laser by the laser irradiation unit 100 so that the pulse width of the peak output laser and the base output laser decreases over time. Furthermore, in the case of the welding apparatus 10 of the present invention, the laser output control unit 200 can also control the irradiation of the laser by the laser irradiation unit 100 so that both the output and pulse width of the peak output laser and the base output laser decrease over time.

[0097] Thus, in the case of the welding apparatus 10 of the present invention, even if the laser irradiation is controlled as shown in Figure 11 or Figure 12, the liquid state of the weld W can be maintained by irradiating the weld W with the base output laser. Therefore, compared to conventional methods, welding defects can be minimized while inputting less energy to the weld W.

[0098] The effects of the welding apparatus 10 of the present invention will be more specifically illustrated below with reference to examples and comparative examples. However, the examples of the present invention can be modified into various other forms, and the scope of the present invention should not be construed as being limited to the examples described below.

[0099] (Examples 1 to 10) As shown in Figure 1, welding was performed on the weld area W using a welding apparatus (model name: laser (Trumpf TruDiode 4006), optical system (Trumpf BEO D70 0°K200 F200 T950)).

[0100] In all embodiments, the weld W was constructed from pure aluminum, with the top and bottom thicknesses of the pressed Mono-frame AL6063 being 2.0 mm and the side thickness being 3.2 mm. The die-cast Endplate ADC12 was machined to correspond to the thickness of each face of the Mono-frame. The total length of the weld W was 562 mm on one side and 1124 mm on both sides. The total width of the weld W was set to a bead width of 2.0 mm to 4.0 mm. The length of a single weld line was 80 mm on the top side, 96 mm on the side side, and 210 mm on the bottom side. The weld W served as a joint between components of a battery module (not shown). Specifically, the weld W served as a joint between a module case (not shown) and an end plate (not shown).

[0101] Furthermore, as shown in Figure 2, the welding apparatus was configured to alternately and continuously irradiate the weld area W with a peak power laser and a base power laser. At this time, the output of the peak power laser was set to 3300W ± 200W in the 2.0mm thick section on the top / bottom side and 3600W ± 200W in the 3.2mm thick section on the side. The output of the base power laser was set to 1200W ± 200W in the 2.0mm thick section on the top / bottom side and 2000W ± 200W in the 3.2mm thick section on the side. In addition, the number of welds per welding line was 1, the welding speed per welding line was 60mm / sec, the total welding length was 1124mm, and the total welding time was 18.7 seconds. Furthermore, the number of welds for each weld W containing at least one weld line was one, and the total welding time for each weld W was 1.33 seconds for the 80mm section on the top side, 1.6 seconds for the 96mm section on the side side, and 3.5 seconds for the 210mm section on the bottom side. In addition, the irradiation time of the peak power laser and the irradiation time of the base power laser were kept at the same ratio.

[0102] Furthermore, the welding apparatus was configured to alternately irradiate the welding line with a peak-power laser and a base-power laser so that two or more keyholes K are superimposed on a single welding line, as shown in Figure 3.

[0103] In an embodiment of the present invention, a welded joint W was formed by welding in the manner described above, and the quality of the weld was measured for the formed welded joint W. More specifically, multiple samples were produced in the manner described above every week for 10 weeks, and the number of samples in which welding defects occurred in the welded joint W was counted, and the results are shown in Table 1. That is, Table 1 shows the data from the experiment conducted over a total of 10 weeks, labeled as Example 1 to Example 10 for each week, and for each embodiment, it shows the number of battery modules produced in one week and the number of welding defects (e.g., burn-through) in the welded joint W included in the produced battery modules, i.e., each sample.

[0104] (Comparative example) On the other hand, the comparative example shows a case where welding was performed by irradiating the weld area with only the peak power laser using the conventional PW (Pulse Wave) laser welding method shown in Figure 5. In this case, the weld area was made of pure aluminum material, and the thickness of the top / bottom of the pressed Mono-frame AL6063 was set to 2.0 mm, and the thickness of the side was set to 3.2 mm. The die-cast Endplate ADC12 was processed to correspond to the thickness of each side of the Mono-frame. The total length of the weld area was 562 mm on one side and 1124 mm on both sides. The total width of the weld area was set to a bead width of 2.0 mm to 4.0 mm. The length of one welding line was 80 mm on the top side, 96 mm on the side side, and 210 mm on the bottom side. The weld area was a joint between components of a battery module (not shown). Specifically, the weld area was a joint between a module case (not shown) and an end plate (not shown).

[0105] Furthermore, the peak power laser output was set to 3300W ± 200W in the 2.0mm thick section on the Top / Bottom side, and 3600W ± 200W in the 3.2mm thick section on the Side side. The number of welds per welding line was 1, the welding speed per welding line was 10mm / sec, the total weld length was 1124mm, and the total welding time was 112.4 seconds. Additionally, the number of welds per weld section, including at least one welding line, was 1, and the total welding time per weld section was 8 seconds for the 80mm section on the Top side, 9.6 seconds for the 96mm section on the Side side, and 21 seconds for the 210mm section on the Bottom side. The irradiation time of the peak power laser and the time in sections where the laser was not irradiated were kept at the same ratio.

[0106] [Table 1]

[0107] Referring to the results in Table 1 above, it can be seen that the incidence of welding defects was very low in Examples 1 to 10, while the incidence of welding defects was far higher in the comparative example compared to Examples 1 to 10.

[0108] To examine this in more detail, in Example 1, 2,560 battery modules were produced in one week, and in this case, there was only one welding defect at the weld W. In this case, the welding defect rate was only about 0.04%.

[0109] In Example 2, 15,285 battery modules were produced in one week, and in this case, there were 6 welding defects in the weld W. In this case, the welding defect rate was only about 0.04%.

[0110] In Example 3, 16,987 battery modules were produced in one week, and in this case, there were 7 welding defects in the weld W. In this case, the welding defect rate was only about 0.04%.

[0111] In Example 4, 20,200 battery modules were produced in one week, and in this case, there were 0 welding defects in the welded area W.

[0112] In Example 5, 20,416 battery modules were produced in one week, and in this case, there were 7 welding defects in the weld W. In this case, the welding defect rate was only about 0.03%.

[0113] In Example 6, 20,421 battery modules were produced in one week, and in this case, there were 8 welding defects in the weld W. In this case, the welding defect rate was only about 0.04%.

[0114] In Example 7, 30,562 battery modules were produced in one week, and in this case, there were 9 welding defects in the weld W. In this case, the welding defect rate was only about 0.03%.

[0115] In Example 8, 28,093 battery modules were produced in one week, and in this case, there were 6 welding defects in the weld W. In this case, the welding defect rate was only about 0.02%.

[0116] In Example 9, 34,220 battery modules were produced in one week, and in this case, there were 9 welding defects at the weld W. In this case, the welding defect rate was only about 0.03%.

[0117] In Example 10, 23,889 battery modules were produced in one week, and in this case, there were 3 welding defects in the weld W. In this case, the welding defect rate was only about 0.01%.

[0118] In other words, as can be seen in Table 1 above, in each embodiment, regardless of the production volume of the battery module, the number of welding defects in the welded area W was almost zero (less than 10 times).

[0119] In particular, while one welding defect occurred when 2,560 products were produced in week 22 of Example 1, only nine welding defects occurred when 30,562 products were produced in week 28 of Example 7, despite increasing the product production volume by more than tenfold compared to Example 1.

[0120] On the other hand, referring to Table 1 above, the comparative example shows the number of welding defects in the welded parts of battery modules produced in one week during the mass production process of battery modules.

[0121] Specifically, in the comparative example, 10,040 products were produced in one week, and in this case, the number of welding defects in the welded joints was 27. In this case, the welding defect rate was approximately 0.27%. Furthermore, this welding defect rate is significantly higher than the average welding defect rate of 0.028% in Examples 1 to 10.

[0122] In particular, it was found that the comparative example had more welding defects than Example 1, which had approximately 20% of the number of products produced in the comparative example.

[0123] Furthermore, in the comparative example, it was found that more welding defects occurred than in Example 2, which produced approximately 5,000 more products than the comparative example.

[0124] As can be seen from these results, in the case of the welding apparatus 10 according to the embodiment of the present invention, welding defects in the welded area W can be minimized compared to the conventional laser welding method.

[0125] The battery manufacturing apparatus according to the present invention may include the welding apparatus 10 described above. In addition, the battery manufacturing apparatus according to the present invention may further include various known devices for manufacturing battery modules (e.g., battery module inspection apparatus) in addition to the welding apparatus 10 described above.

[0126] The automobile manufacturing apparatus according to the present invention may include the welding apparatus 10 described above. Furthermore, the automobile manufacturing apparatus according to the present invention may further include various known apparatuses for manufacturing automobiles (e.g., automobile inspection apparatus) in addition to the welding apparatus 10 described above.

[0127] As described above, the present invention has been explained with limited embodiments and drawings, but the present invention is not limited thereto, and it goes without saying that any person with ordinary skill in the art to which the present invention belongs can make various modifications and variations within the equivalent scope of the technical idea of ​​the present invention and the following claims.

[0128] On the other hand, while terms indicating directions such as up, down, left, right, front, and back are used in this invention, these terms are for convenience of explanation and it will be obvious to those skilled in the art that they can change depending on the position of the object in question, the position of the observer, etc. [Explanation of Symbols]

[0129] 10 Welding equipment 100 Laser irradiation area 200 Laser output control unit 300 Inspection Department

Claims

1. A laser irradiation unit configured to emit a laser, A laser output control unit configured to control the laser irradiation unit so as to irradiate the welding area with a peak output laser and a base output laser, Includes, The aforementioned peak-power laser is Having an output capable of forming a keyhole in the welded portion, The aforementioned base output laser is Having an output smaller than the aforementioned peak output laser, The laser output control unit, The laser irradiation unit is configured to control the peak output laser and the base output laser to irradiate the weld area alternately and continuously in time. The laser output control unit, A welding apparatus configured to control the laser irradiation unit such that the welded area remains in a liquid state, and both the output and pulse width of the peak output laser and the base output laser decrease over time.

2. The laser output control unit, The welding apparatus according to claim 1, configured to control the pulse frequency of the output laser of the base.

3. The welding apparatus is The system further includes an inspection unit configured to inspect the welding condition at the welded area after welding is completed by the welding apparatus, The laser output control unit, The welding apparatus according to claim 1, configured to control the output of the base output laser in accordance with welding condition inspection information provided by the inspection unit.

4. The welding apparatus is The device further includes an inspection unit configured to inspect the welding condition at the welded area during welding by the welding apparatus, The laser output control unit, The welding apparatus according to claim 1, configured to control the output of the base output laser in accordance with welding condition inspection information provided by the inspection unit.

5. The steps include: irradiating the weld area with a peak-power laser, The steps include irradiating the welding area with a base output laser, Includes, The aforementioned peak-power laser is Having an output capable of forming a keyhole in the welded portion, The aforementioned base output laser is Having an output smaller than the aforementioned peak output laser, The peak power laser and the base power laser are configured to irradiate the weld area alternately and continuously over time. A welding method in which the welded area remains in a liquid state, and both the output and pulse width of the peak output laser and the base output laser are configured to decrease over time.

6. A battery manufacturing apparatus comprising a welding apparatus according to any one of claims 1 to 4.

7. An automobile manufacturing apparatus comprising a welding apparatus according to any one of claims 1 to 4.

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