Electrode lead welding method

Abstract

The present invention relates to an electrode lead welding method for welding electrode leads of a cell assembly composed of a plurality of cells, the method comprising the steps of: preparing a cell stack in which a plurality of cells, each having an electrode lead extending therefrom, are stacked; preparing a bus bar frame having a lead connection portion including a pair of lead slits spaced a predetermined distance apart; coupling the cell stack and the bus bar frame together so that the electrode leads of the cell stack are inserted through the lead slits; bending the electrode leads that have passed through the lead slits of the lead connection portion toward each other so that they overlap; and welding the pair of overlapped electrode leads, wherein the lead connection portion includes an insertion groove between the pair of lead slits, and the method further comprises the step of inserting a weld prevention bar into the insertion groove so that the weld prevention bar is spaced a predetermined distance apart from a rear surface of the electrode lead.

Description

[Technical Field]

[0001] The present invention relates to an electrode lead welding method for welding electrode leads of a cell assembly composed of a plurality of cells, and is characterized by providing a method for welding electrode leads using a weld prevention bar to prevent a bus bar frame from being damaged by welding when welding to electrically connect the electrode leads.

[0002] This application claims the benefit of priority based on Korean Patent Application No. 10-2023-0088782, filed on July 10, 2023, and all contents disclosed in the documents of said Korean patent application are incorporated herein by reference. [Background technology]

[0003] FIG. 1 shows a cell assembly 1 including a cell stack 10 in which a plurality of cells 11 are stacked, each having an electrode lead 12 extending from both sides.

[0004] The cell assembly 1 includes a cell stack 10 and a bus bar frame 20 coupled to at least one side of the cell stack 10 .

[0005] In the case of the conventional cell assembly 1, a bus bar 21 was used to electrically connect the stacked cells 11 to each other, and multiple electrode leads 12 drawn out from each of the multiple cells 11 were positioned on the bus bar 21 and then welded.

[0006] At this time, the bus bars 21 are positioned on the bus bar frame 20 at predetermined intervals, and the welding is performed by a welding unit that is provided so as to be freely movable on the bus bar frame 20 .

[0007] The welding can be performed toward the surface of the electrode lead 12 that is led out to the front surface of the bus bar frame 20 and bent, as shown in FIG.

[0008] The above welding completes the electrical connection between the electrode lead 12 and the bus bar 21 .

[0009] However, there may be a problem that the heat generated during the welding is transferred to the bus bar frame 20.

[0010] Since the conventional bus bar frame 20 may be made of plastic material, the high temperature generated by the welding may have a fatal effect. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] Korean Patent Publication No. 10-2015-0038930 Summary of the Invention [Problem to be solved by the invention]

[0012] Therefore, the present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a welding method that can prevent damage to a bus bar frame when welding an electrode lead.

[0013] Another object of the present invention is to provide a welding method that can prevent contact damage to electrode leads by using a welding prevention bar that is provided to prevent damage to the bus bar frame during the welding process.

[0014] Other objects and advantages of the present invention can be understood from the following description and become more apparent from the embodiments of the present invention, and it is easily understood that the objects and advantages of the present invention can be realized by the means and combinations thereof as set forth in the claims. [Means for solving the problem]

[0015] According to the present invention, there is provided an electrode lead welding method, comprising the steps of: preparing a cell stack in which a plurality of cells, each having an electrode lead drawn therethrough, are stacked; preparing a bus bar frame having a lead connection portion including a pair of lead slits spaced apart by a predetermined interval; coupling the cell stack and the bus bar frame together so that the electrode leads of the cell stack are inserted through the lead slits; bending the electrode leads that have passed through the lead slits of the lead connection portion toward each other so that they overlap; and welding the pair of overlapped electrode leads, wherein the lead connection portion includes an insertion groove between the pair of lead slits, and the method further comprises the step of inserting a weld prevention bar into the insertion groove so that the weld prevention bar is spaced apart by a predetermined interval from a rear surface of the electrode lead.

[0016] The welding can be performed by laser welding.

[0017] The insertion groove may be formed to extend along the longitudinal direction of the lead slit.

[0018] The bus bar frame may include a plurality of lead connections.

[0019] The bus bar frame may include a bus bar mounted on the insertion groove so as to be in contact with the bent electrode lead, and the bus bar and the electrode lead may be joined to each other by welding in a welding step.

[0020] The bus bar frame may include a bus bar insertion portion supporting a rear surface of the bus bar, and the bus bar insertion portion may be located at an end of the insertion groove in a longitudinal direction of the bus bar frame and at an upper portion of the insertion groove in a thickness direction of the bus bar frame.

[0021] At least one electrode lead can pass through the lead slit.

[0022] Electrode leads of different polarities may pass through a pair of lead slits included in the lead connection portion.

[0023] The temperature of the heat generated by the welding is 2000°C or higher, The weld prevention bar may include a heat-resistant material capable of withstanding the heat generated by the welding.

[0024] a plurality of the weld prevention bars are provided at the end of a prevention bar frame configured to be reciprocally movable back and forth toward the bus bar frame; The weld prevention bars may be spaced apart at predetermined intervals at the ends of the prevention bar frame.

[0025] The weld prevention bars may be positioned at the end of the prevention bar frame in correspondence with the spacing of the insertion grooves of the bus bar frame.

[0026] The thickness of the weld prevention bar may be smaller than the depth of the insertion groove.

[0027] The weld prevention bar may be inserted into the insertion groove in the step of preparing the bus bar frame.

[0028] The weld prevention bar can be inserted into the insertion groove during the step of bending the electrode lead.

[0029] A plate-shaped weld filler that melts during the welding can be interposed between the pair of overlapping electrode leads and the insertion groove of the bus bar frame. [Effects of the Invention]

[0030] According to the present invention, electrode leads, bus bars, etc. can be welded without damaging the components.

[0031] Furthermore, according to the present invention, the electrode leads can be prevented from being damaged by contact with the welding prevention bar used to prevent the bus bar frame from being damaged during welding. [Brief explanation of the drawings]

[0032] [Figure 1] FIG. 1 is a perspective view of a conventional cell assembly. [Figure 2] 2 is an enlarged view of a portion of the cell assembly shown in FIG. 1. [Figure 3] 1 shows a flowchart of an electrode lead welding method according to a first embodiment of the present invention. [Figure 4] Each step in the flowchart of FIG. 3 is shown using a cell stack and a bus bar frame. [Figure 5] FIG. 2 is a perspective view of the bus bar frame of the present invention. [Figure 6] 6 is a diagram showing the bus bar frame of FIG. 5 cut horizontally. [Figure 7] FIG. 7 is a plan view of FIG. 6. [Figure 8] This is the bus bar frame shown in Figure 7, to which a weld prevention bar has been applied. [Figure 9] FIG. 9 is a front view of the bus bar frame of FIG. 8. [Figure 10] This is an enlarged view of a part of FIG. 8. [Figure 11] 1 shows a weld prevention bar coupled to a prevention bar frame. [Figure 12] 1 shows a portion of a bus bar frame with bent electrode leads. [Figure 13] 13 is a cross-sectional view of the bus bar frame of FIG. 12, in which a part of the bus bar frame is cut away. [Figure 14] 1 shows a cross section of a portion of a busbar frame with weld filler applied. [Figure 15] 10 is a simplified illustration of the process of removing the weld prevention bar after welding. [Figure 16]10 shows a flowchart of an electrode lead welding method according to a second embodiment of the present invention. [Figure 17] Some of the steps in the flowchart of FIG. 16 are shown using a cell stack and a bus bar frame. DETAILED DESCRIPTION OF THE INVENTION

[0033] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Before that, the terms and words used in the specification and claims are not to be construed as being limited to their ordinary or dictionary meanings, but are to be construed as meanings and concepts that are consistent with the technical idea of ​​the present invention, based on the principle that the inventor can appropriately define the concepts of the terms in order to best describe his own invention.

[0034] Therefore, the embodiments described in this specification and the configurations shown in the drawings are merely the most preferred embodiments of the present invention and do not represent the entire technical idea of ​​the present invention, and there may be various equivalents and modifications that can replace them at the time of this application.

[0035] Furthermore, in the description of the present invention, if it is determined that a detailed description of related publicly known structures or functions may obscure the gist of the present invention, the detailed description will be omitted.

[0036] The embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art, and therefore the shapes and sizes of components in the drawings may be exaggerated, omitted, or shown in a schematic manner for clearer explanation. Therefore, the sizes and proportions of each component do not completely reflect the actual sizes and proportions.

[0037] The present invention relates to an electrode lead welding method for welding electrode leads of a cell assembly composed of a plurality of cells, and is characterized by providing a method for welding electrode leads using a weld prevention bar to prevent a bus bar frame from being damaged by welding when welding to electrically connect the electrode leads.

[0038] 3 to 15 relate to an electrode lead welding method according to a first embodiment of the present invention, and FIGS. 16 and 17 relate to an electrode lead welding method according to a second embodiment of the present invention.

[0039] The electrode lead welding method of the present invention will be described below with reference to the drawings.

[0040] (First embodiment) Fig. 3 shows a flowchart of a method for welding an electrode lead 111 according to the first embodiment of the present invention. Fig. 4 shows each step of the flowchart of Fig. 3 using a cell stack 100 and a bus bar frame 200.

[0041] As shown in FIG. 3, the welding method for the electrode lead 111 according to the first embodiment of the present invention basically comprises a cell stack 100 preparation step S1, a bus bar frame 200 preparation step S2, a joining step S3, a bending step S4, and a welding step S5, with an insertion step S2' being further added to the above basic configuration.

[0042] Each step will be described below with reference to FIGS.

[0043] <Cell stack 100 preparation step S1> This is a step for preparing a cell stack 100 in which a plurality of cells 110, each having an electrode lead 111, are stacked.

[0044] The cell 110 includes an electrode assembly formed by stacking electrodes and a separator, an electrode lead 111 electrically connected to the electrode assembly, a case that encloses and seals the electrode assembly so that the electrode lead 111 is led out, and an electrolyte filled inside the case together with the electrode assembly.

[0045] The cell 110 of the present invention includes a pair of electrode leads 111 having opposite polarities.

[0046] The cell stack 100 includes a plurality of cells 110 stacked in one direction so that electrode leads 111 can be arranged side by side at predetermined intervals.

[0047] <Bus bar frame 200 preparation step S2> This is a step of preparing a bus bar frame 200 having a lead connection portion 200p including a pair of lead slits 230 spaced apart at a predetermined interval.

[0048] The bus bar frame 200 includes bus bars 210 that can be electrically connected to the electrode leads 111 of the cell stack 100 .

[0049] The bus bar frame 200 is coupled to the cell stack 100 to fix the cell stack 100, and at the same time supports the rear surfaces of the electrode leads 111 led out from the cell stack 100 so that the electrode leads 111 can be fixed to the bus bar 210.

[0050] FIG. 5 is a perspective view of a bus bar frame 200 of the present invention, FIG. 6 is a horizontally cut view of the bus bar frame 200 of FIG. 5, and FIG. 7 is a plan view of FIG.

[0051] The lead connection portion 200p is composed of a pair of lead slits 230 and an insertion groove 220 formed between the lead slits 230.

[0052] The bus bar frame 200 may have a plurality of lead connection portions 200p formed thereon in accordance with the number of electrode leads 111 of the cell stack 100 to be coupled thereto.

[0053] The lead slit 230 is opened so that the electrode lead 111 can pass through.

[0054] The lead slit 230 is formed in a shape that allows the electrode lead 111 of the cell stack 100 to be coupled with the bus bar frame 200 to pass through.

[0055] The lead slit 230 of the present invention is formed to extend along the shorter width direction of the bus bar frame 200.

[0056] The insertion groove 220 is formed in a recessed shape with a certain depth in the thickness direction of the bus bar frame 200 .

[0057] The insertion groove 220 prevents the bus bar frame 200 from coming into direct contact with heat generated by welding and also serves as a passageway for gases and by-products generated by welding. In particular, in the present invention, the insertion groove 220 is an area into which a weld prevention bar 310 is inserted, which is used to protect the surface of the bus bar frame 200 from the welding heat.

[0058] The insertion groove 220 is formed to extend along the longitudinal direction of the lead slit 230 .

[0059] The bus bar 210 is mounted on the insertion groove 220 so as to be in electrical contact with the electrode lead 111 passing through the lead slit 230. That is, one lead connection portion 200p may include one bus bar 210.

[0060] The bus bar frame 200 further includes a bus bar 210 insertion portion formed to be recessed in a thickness direction of the bus bar frame 200 so that the bus bar 210 can be inserted therein.

[0061] The insertion portion of the bus bar 210 may be formed at an end of the insertion groove 220. That is, the insertion portion of the bus bar 210 is located at an end of the insertion groove 220 in the shorter width direction of the bus bar frame 200.

[0062] The bus bar 210 insertion portion may be formed to overlap the insertion groove 220. That is, the bus bar 210 insertion portion may be located above the insertion groove 220 in the thickness direction of the bus bar frame 200.

[0063] The bus bar 210 is inserted into the bus bar 210 insertion portion so that the rear surface thereof can be supported.

[0064] <Insertion step S2'> This is a step of inserting the weld prevention bar 310 into the insertion groove 220 of the bus bar frame 200.

[0065] The weld prevention bar 310 of the present invention can be inserted into the insertion groove 220 in the step of preparing the bus bar frame 200. Therefore, the step S2 of preparing the bus bar frame 200 of the present invention can include an inserting step S2'.

[0066] The weld prevention bar 310 is used to prevent the bus bar frame 200 from being directly damaged by high heat generated by welding. That is, the weld prevention bar 310 is installed on the surface of the area to be protected from welding.

[0067] The weld prevention bar 310 preferably includes a heat-resistant material that can withstand the heat generated by welding, for example, the weld prevention bar may include carbon steel.

[0068] In the method for welding the electrode lead 111 according to the first embodiment of the present invention, in the step of preparing the bus bar frame 200, the weld prevention bar 310 is coupled to the bus bar frame 200.

[0069] The weld prevention bar 310 is detachably inserted into the insertion groove 220 in various forms.

[0070] FIG. 8 shows the bus bar frame 200 of FIG. 5 to which a weld prevention bar 310 has been applied, FIG. 9 is a front view of the bus bar frame 200 of FIG. 8, and FIG. 10 is an enlarged view of a portion of FIG. 8.

[0071] The weld prevention bar 310 includes a bar-shaped prevention portion 310a that is elongated so that it can be inserted into the insertion groove 220, and a protrusion 310b that has a width greater than that of the prevention portion 310a at the end of the prevention portion 310a so that it can be caught in the entrance of the insertion groove 220.

[0072] The weld prevention bar 310 is coupled to the bus bar frame 200 by sliding the prevention portion 310a into the insertion portion of the bus bar frame 200 and hooking the protrusion 310b onto the end of the bus bar frame 200 in a protruding shape.

[0073] The weld prevention bar 310 is inserted into the insertion groove 220 so as to contact the bottom of the insertion groove 220 .

[0074] The above-mentioned multiple weld prevention bars 310 may be inserted into the required insertion grooves 220 independently as shown in Figures 8 and 9, or may be combined with one prevention bar frame 300 and inserted into each insertion groove 220 simultaneously.

[0075] FIG. 11 shows a weld prevention bar 310 coupled to a prevention bar frame 300 .

[0076] The weld prevention bar 310 is provided in plurality at the end of the prevention bar frame 300 configured to be reciprocable back and forth toward the bus bar frame 200. Specifically, the protrusion 310b of the weld prevention bar 310 is coupled to the end of the prevention bar frame 300.

[0077] The plurality of weld prevention bars 310 coupled to the prevention bar frame 300 are arranged to face in one direction from one side of the prevention bar frame 300 .

[0078] As shown in FIG. 11, the weld prevention bars 310 are positioned at the ends of the prevention bar frame 300 at predetermined intervals.

[0079] Each of the weld prevention bars 310 is located at an end of the prevention bar frame 300 in accordance with the spacing of the insertion grooves 220 of the bus bar frame 200. That is, the position of each of the weld prevention bars 310 coupled to the prevention bar frame 300 is affected by the spacing of the insertion grooves 220.

[0080] The thickness of the weld prevention bar 310 used in the electrode lead 111 welding method of the present invention is preferably smaller than the depth of the insertion groove 220. If the thickness of the weld prevention bar 310 is the same as or smaller than the depth of the insertion groove 220, a problem may occur in that the weld prevention bar 310 comes into contact with the electrode lead 111 when sliding in the insertion groove 220.

[0081] <Combining step S3> This is a step of joining the cell stack 100 and the bus bar frame 200 so that the electrode leads 111 of the cell stack 100 are inserted through the lead slits 230 .

[0082] A plurality of electrode leads 111 extending from one side of the cell stack 100 are inserted through a plurality of lead slits 230 formed in the bus bar frame 200 .

[0083] At least one electrode lead 111 passes through one lead slit 230 .

[0084] Electrode leads 111 of mutually opposite polarities pass through a pair of lead slits 230 included in the lead connection portion 200p.

[0085] <Folding step S4> This is a step in which the electrode leads 111 that have passed through the lead slits 230 of the lead connection portion 200p are bent toward each other so as to overlap each other.

[0086] FIG. 12 shows a part of bus bar frame 200 in which electrode leads 111 are bent.

[0087] The electrode leads 111 that pass vertically through the lead slits 230 are bent at approximately right angles and overlap each other so that they can be supported on the front surface of the bus bar frame 200 .

[0088] FIG. 13 is a cross-sectional view of the bus bar frame 200 of FIG. 12, in which a part of the bus bar frame 200 is cut away.

[0089] As shown in Fig. 13, the electrode lead 111 welding method of the present invention is characterized in that the weld prevention bar 310 is spaced apart from the rear surface of the electrode lead 111 by a predetermined distance and does not come into contact with the rear surface. That is, it is preferable that the rear surface of the bent electrode lead 111 is supported only by the bus bar frame 200. At this time, the front surface of the bus bar 210 is in contact with and connected to the rear surface of the bent electrode lead 111, as shown in Fig. 13.

[0090] A welding filler 400 that melts by welding can be interposed between the pair of overlapping electrode leads 111 and the insertion groove 220 of the bus bar frame 200 .

[0091] FIG. 14 shows a cross section of a portion of the bus bar frame 200 to which the weld filler 400 has been applied.

[0092] The weld filler 400 may be plate-shaped, and both ends may be bent toward the bus bar frame 200 as shown in FIG.

[0093] Both ends of the bent weld filler 400 can be inserted into the lead slits 230 of the lead connection portion 200p.

[0094] <Welding step S5> This is a step of welding a pair of overlapping electrode leads 111 together.

[0095] The welding can be performed by laser welding.

[0096] The temperature of the heat generated at the welded portion by the above welding is 2000°C or higher.

[0097] The electrode leads 111 can be joined to each other or the electrode leads 111 and the bus bar 210 can be joined by the welding.

[0098] <Removal step S6> The method for welding the electrode lead 111 of the present invention may further include a step of removing the weld prevention bar 310 inserted into the insertion groove 220.

[0099] The weld prevention bar 310 has no additional purpose other than protecting the bus bar frame 200 from welding, and is therefore preferably removed to reduce the weight of the cell 110 assembly.

[0100] Therefore, the inserted weld prevention bar 310, or the weld prevention bar 310 and the prevention bar frame 300, are retracted and removed from the bus bar frame 200.

[0101] FIG. 15 shows a simplified process of removing the weld prevention bar 310 after welding.

[0102] The weld prevention bar 310 is tightly coupled to the bottom of the insertion groove 220 to protect the bottom of the insertion groove 220 from the welding heat. At this time, the weld prevention bar 310 is not joined to the electrode lead 111, the weld filler 400, etc. by welding.

[0103] Referring to FIG. 15, after the welding is completed, the weld prevention bar 310 is separated from the insertion groove 220 and removed.

[0104] (Second embodiment) The step of inserting the weld prevention bar 310 may be included in the step of preparing the bus bar frame 200, or may be included in any step between the step of preparing the bus bar frame 200 and the welding step.

[0105] Fig. 16 shows a flowchart of a method for welding an electrode lead 111 according to a second embodiment of the present invention. Fig. 17 shows some of the steps in the flowchart of Fig. 16 using a cell stack 100 and a bus bar frame 200.

[0106] The electrode lead 111 welding method according to the second embodiment of the present invention basically comprises a cell stack 100 preparation step S1, a bus bar frame 200 preparation step S2, a joining step S3, a bending step S4, and a welding step S5, with an insertion step S4' being further added to the above basic configuration.

[0107] The method for welding the electrode lead 111 according to the second embodiment of the present invention is different from the method for welding the electrode lead 111 according to the first embodiment in that the weld prevention bar 310 is not prepared by being inserted into the insertion groove 220 in the step of preparing the bus bar frame 200. In other words, the weld prevention bar 310 is inserted in the step immediately before each welding step.

[0108] Referring to FIG. 16, the weld prevention bar 310 is inserted into the insertion groove 220 during the step of bending the electrode lead 111 .

[0109] However, the thickness of the weld prevention bar 310 is smaller than the depth of the insertion groove 220. Therefore, when the weld prevention bar 310 is slid and inserted into the insertion groove 220, the weld prevention bar 310 and the bent electrode lead 111 do not come into contact with each other.

[0110] The method for welding the electrode lead 111 according to the second embodiment of the present invention may further include a step of removing the weld prevention bar 310 inserted into the insertion groove 220, as in the first embodiment.

[0111] The weld prevention bar 310 has no additional purpose other than protecting the bus bar frame 200 from welding, and is therefore preferably removed to reduce the weight of the cell 110 assembly.

[0112] Therefore, the inserted weld prevention bar 310, or the weld prevention bar 310 and the prevention bar frame 300, are retracted and removed from the bus bar frame 200.

[0113] The weld prevention bar 310 is tightly coupled to the bottom of the insertion groove 220 to protect the bottom of the insertion groove 220 from the welding heat. At this time, the weld prevention bar 310 is not joined to the electrode lead 111, the weld filler 400, etc. by welding.

[0114] After the welding is completed, the weld prevention bar 310 is separated from the insertion groove 220 and removed.

[0115] The present invention has been described in more detail above with reference to the drawings and embodiments, etc. However, the configurations shown in the drawings or embodiments in this specification are merely one embodiment of the present invention and do not represent all of the technical ideas of the present invention, and therefore, at the time of filing this application, there may be various equivalents and modifications that can replace them. [Explanation of symbols]

[0116] 1: (Prior Art) Cell Assembly 10: (Conventional technology) Cell stack 11: (Prior Art) Cell 12: (Prior Art) Electrode Lead 20: (Prior Art) Busbar Frame 21: (Conventional technology) Busbar 100: Cell stack 110: Cell 111: Electrode lead 200: Busbar frame 200p: Lead connection part 210: Busbar 220: Insertion groove 230: Lead slit 300: Prevention bar frame 310: Weld prevention bar 310a: Prevention part 310b:Protrusion 400: Welding filler S1: Cell stack preparation step S2: Busbar frame preparation step S3: Combination step S4: Folding step S2', S4': Insertion steps S5: Welding step S6: Withdrawal step W: Welding

Claims

1. 1. An electrode lead welding method for welding electrode leads of a cell assembly composed of a plurality of cells, comprising: preparing a cell stack in which a plurality of cells having electrode leads led out therefrom are stacked; preparing a bus bar frame having a lead connection portion including a pair of lead slits spaced apart by a predetermined distance; coupling the cell stack and the bus bar frame together so that the electrode leads of the cell stack are inserted through the lead slits; bending the electrode leads so that the electrode leads passing through the lead slits of the lead connection portion overlap each other; and welding the pair of overlapping electrode leads together. the lead connection portion includes an insertion groove between a pair of lead slits, The electrode lead welding method includes: The method further includes inserting a weld prevention bar into the insertion groove before the welding step; The welding prevention bar is inserted into the insertion groove so as to be spaced a predetermined distance from the rear surface of the electrode lead.

2. The electrode lead welding method according to claim 1 , wherein the welding is performed by laser welding.

3. The electrode lead welding method according to claim 1 , wherein the insertion groove is formed to extend along the longitudinal direction of the lead slit.

4. The electrode lead welding method according to claim 1 , wherein the bus bar frame includes a plurality of lead connection portions.

5. the bus bar frame includes a bus bar mounted on the insertion groove so as to be in contact with the bent electrode lead, The electrode lead welding method according to claim 1 , wherein the bus bar and the electrode lead are joined to each other by welding in the welding step.

6. the bus bar frame includes a bus bar insertion portion that supports a rear surface of the bus bar, The bus bar insertion portion is the bus bar frame is positioned at an end of the insertion groove in a width direction of the bus bar frame; The electrode lead welding method according to claim 5 , wherein the electrode lead is located above the insertion groove with respect to the thickness direction of the bus bar frame.

7. The electrode lead welding method according to claim 1 , wherein at least one electrode lead passes through the lead slit.

8. The electrode lead welding method according to claim 1 , wherein electrode leads of different polarities pass through a pair of lead slits included in the lead connection portion.

9. The temperature of the heat generated by the welding is 2000°C or higher, The electrode lead welding method according to claim 1 , wherein the weld prevention bar includes a heat-resistant material that can withstand heat generated by the welding.

10. a plurality of the weld prevention bars are provided at the end of a prevention bar frame configured to be reciprocally movable back and forth toward the bus bar frame; 2. The electrode lead welding method of claim 1, wherein each of the weld prevention bars is spaced apart at a predetermined interval from an end of the prevention bar frame.

11. The electrode lead welding method according to claim 10 , wherein each of the weld prevention bars is located at an end of the prevention bar frame corresponding to a spacing between the insertion grooves of the bus bar frame.

12. The electrode lead welding method according to claim 1 , wherein the thickness of the weld prevention bar is smaller than the depth of the insertion groove.

13. The electrode lead welding method according to claim 1 , wherein the weld prevention bar is inserted into the insertion groove in the step of preparing a bus bar frame.

14. The electrode lead welding method according to claim 1 , wherein the weld prevention bar is inserted into the insertion groove during the step of bending the electrode lead.

15. The electrode lead welding method according to claim 1 , wherein a plate-shaped weld filler that melts during the welding is interposed between the pair of overlapping electrode leads and the insertion groove of the bus bar frame.

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