Electrode lead welding method

Abstract

The present invention relates to an electrode lead welding method for welding an electrode lead of a cell assembly comprising a plurality of cells. The electrode lead welding method comprises the following steps: preparing a battery cell stack in which a plurality of battery cells from which electrode leads are led out are stacked; preparing a bus bar frame having a lead connection unit including a pair of lead slits spaced apart from each other by a predetermined distance; coupling the cell stack and the bus bar frame such that an electrode lead of the cell stack is inserted through the lead slit; bending the electrode leads passing through the lead slits of the lead connection unit so as to face each other; and welding the overlapping pair of electrode leads, in which the lead connection unit includes an insertion groove located between the pair of lead slits, the method further including a step of inserting an anti-welding rod into the insertion groove before the welding step, and the anti-welding rod is inserted into the insertion groove to be spaced apart from the rear surfaces of the electrode leads by a predetermined distance.

Description

Technical Field

[0001] The present invention relates to an electrode lead welding method for welding electrode leads of a battery cell assembly composed of multiple battery cells, wherein when welding the electrode leads to electrically connect the electrode leads, it provides a method for welding the electrode leads using a welding prevention rod to prevent a busbar frame from being damaged by welding.

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2023-0088782, filed on Jul. 10, 2023, and all contents disclosed in the document of the Korean Patent Application are incorporated as a part of this specification. Background Art

[0003] Figure 1 A cell assembly 1 including a cell stack 10 in which a plurality of cell 11 are stacked is shown, and each cell 11 has electrode leads 12 extending from both sides.

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

[0005] In the case of the conventional battery cell assembly 1 , the bus bar 21 is employed for electrical connection of the stacked battery cells 11 to each other, and a plurality of electrode leads 12 drawn from each of the plurality of battery cells 11 are positioned on the bus bar 21 and welding is performed.

[0006] In this case, a plurality of bus bars 21 are positioned on the bus bar frame 20 at a predetermined distance, and welding is performed by a welding unit provided to freely move on the bus bar frame 20 .

[0007] like Figure 2 As shown, welding may be directed toward the surface of the electrode lead 12 that is led out and bent toward the front surface of the bus bar frame 20 .

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

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

[0010] Since the conventional bus bar frame 20 is typically made of a plastic material, the high temperature heat generated by welding may have a destructive effect.

[0011] [Patent Document] Korean Patent Publication No. 10-2015-0038930 Summary of the invention

[0012] Technical issues

[0013] Therefore, the present invention has been invented to solve the above-mentioned problems, and aims to provide a welding method which can prevent damage to a bus bar frame when welding an electrode lead.

[0014] The present invention also aims to provide a welding method capable of preventing contact damage to electrode leads by a welding prevention rod provided to prevent a bus bar frame from being damaged during a welding process.

[0015] Other objects and advantages of the present invention will be understood from the following description and will become more apparent from the embodiments of the present invention. It will also be apparent that the objects and advantages of the present invention can be achieved by the devices disclosed in the patent claims and their combinations.

[0016] Technical Solution

[0017] According to the present invention, there is provided an electrode lead welding method, which comprises the following steps: preparing a battery cell stack having a plurality of stacked battery cells, and leading electrode leads from the plurality of stacked battery cells; preparing a busbar frame provided with a lead connection portion, the lead connection portion comprising a pair of lead slits spaced apart by a predetermined distance; connecting the battery cell stack and the busbar frame so that the electrode leads of the battery cell stack are inserted through the lead slits; bending the electrode leads passing through the lead slits of the lead connection portion so that the electrode leads overlap each other; and welding the overlapping pair of electrode leads, wherein the lead connection portion comprises an insertion groove between a pair of lead slits, wherein the method further comprises the following steps: inserting an anti-welding rod into the insertion groove before the welding step, wherein the anti-welding rod is inserted into the insertion groove so as to be spaced apart from the rear surface of the electrode lead by a predetermined distance.

[0018] The welding may be performed by laser welding.

[0019] The insertion groove may be formed to extend along a longitudinal direction of the lead slit.

[0020] The bus bar frame may include a plurality of lead connection parts.

[0021] The bus bar frame includes a bus bar mounted on the insertion groove to contact the bent electrode lead, wherein the bus bar and the electrode lead may be coupled to each other by welding in a welding step.

[0022] The busbar frame includes a busbar insertion portion supporting a rear surface of the busbar, wherein the busbar insertion portion may be located at an end of the insertion slot relative to a short width direction of the busbar frame, and the busbar insertion portion may be located on an upper portion of the insertion slot relative to a thickness direction of the busbar frame.

[0023] The lead slit may be penetrated by at least one electrode lead.

[0024] The pair of lead slits included in the lead connection portion may be respectively penetrated by electrode leads of different polarities.

[0025] The temperature of the heat generated by the welding is 2000°C or higher, wherein

[0026] The welding prevention rod may include a heat-resistant material capable of withstanding heat generated from the welding.

[0027] The welding prevention rod is provided in plurality at the end of the protection rod frame so as to be able to reciprocate forward and backward toward the busbar frame, wherein

[0028] Each of the welding prevention bars may be spaced apart by a predetermined distance at an end of the protection bar frame.

[0029] Each of the welding prevention bars may be located at an end of the protection bar frame and correspond to an interval of the insertion groove in the bus bar frame.

[0030] The thickness length of the welding prevention bar may be smaller than the depth of the insertion groove.

[0031] In the step of preparing the bus bar frame, the welding prevention bar may be inserted into the insertion groove.

[0032] In the step of bending the electrode lead, the welding prevention bar may be inserted into the insertion groove.

[0033] A plate-shaped welding filler melted by the welding may be interposed between the overlapped pair of electrode leads and the insertion groove in the busbar frame.

[0034] Beneficial effects

[0035] According to the present invention, electrode leads, bus bars, and the like can be welded without damaging the components.

[0036] Furthermore, according to the present invention, contact damage of the electrode leads can be prevented by the welding prevention rod for preventing the bus bar frame from being damaged during welding. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a perspective view of a conventional battery cell assembly.

[0038] Figure 2 yes Figure 1 An enlarged view of a portion of a battery cell assembly.

[0039] Figure 31 is a flowchart of an electrode lead welding method according to a first embodiment of the present invention.

[0040] Figure 4 The use of a cell stack and busbar frame is shown based on Figure 3 of the flowchart for each step.

[0041] Figure 5 is a perspective view of a busbar frame of the present invention.

[0042] Figure 6 yes Figure 5 The horizontal portion of the busbar frame.

[0043] Figure 7 yes Figure 6 Floor plan.

[0044] Figure 8 Shows the application of anti-welding rods to Figure 7 busbar frame.

[0045] Fig. 9 yes Figure 8 Front view of the busbar frame.

[0046] Fig.10 yes Figure 8 An enlarged view of a portion of.

[0047] Fig.11 An anti-weld bar is shown coupled to a protective bar frame.

[0048] Fig.12 A portion of a busbar frame with bent electrode leads is shown.

[0049] Fig.13 yes Fig.12 A cutaway cross-sectional view of a portion of a busbar frame.

[0050] Fig.14 A partial cross section of a busbar frame with weld filler applied is shown.

[0051] Fig.15 The process of removing the anti-welding rod after welding is simply shown.

[0052] Fig.16 1 is a flowchart of an electrode lead welding method according to a second embodiment of the present invention.

[0053] Fig.17 The use of a cell stack and busbar frame is shown based on Fig.16 A part of each step of the flowchart. DETAILED DESCRIPTION

[0054] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, it should be noted that the terms or words used in this specification and claims should not be interpreted as their ordinary or dictionary meanings, but should be understood in accordance with the meanings and concepts consistent with the technical concept of the present invention based on the principle that the inventor can appropriately define the concepts of the terms to best describe his / her invention.

[0055] Therefore, it should be understood that the embodiments described herein and the configurations shown in the drawings are only the most preferred embodiments of the present invention and are not intended to exhaust the technical concept of the present invention, and that there may be various equivalents and modifications that may replace them upon submission.

[0056] Furthermore, in describing the present invention, detailed descriptions of related known configurations or features are omitted if it is determined that such detailed descriptions would obscure the essence of the present invention.

[0057] Because the embodiments of the present invention are provided to more fully explain the present invention to those skilled in the art, the shapes and sizes of the components in the drawings may be exaggerated, omitted or shown for clarity. Therefore, the size or ratio of each component does not necessarily indicate its actual size or ratio.

[0058] The present invention relates to an electrode lead welding method for welding electrode leads of a battery cell assembly composed of a plurality of battery cells, wherein when welding the electrode leads to electrically connect them, the present invention provides a method for welding the electrode leads using a welding prevention rod to prevent a busbar frame from being damaged by welding.

[0059] Figures 3 to 15 It relates to an electrode lead welding method according to a first embodiment of the present invention, and Figure 16 to Figure 17 The present invention relates to an electrode lead welding method according to a second embodiment of the present invention.

[0060] Hereinafter, an electrode lead welding method of the present invention will be described with reference to the various drawings.

[0061] (First Embodiment)

[0062] Figure 3 1 is a flowchart of a method for welding an electrode lead 111 according to a first embodiment of the present invention. Figure 4 The invention shows a method of using the battery cell stack 100 and the busbar frame 200. Figure 3 of the flowchart for each step.

[0063] The electrode lead 111 welding method according to the first embodiment of the present invention fundamentally includes a cell stack 100 preparation step S1, a busbar frame 200 preparation step S2, a connection step S3, a bending step S4 and a welding step S5. Figure 3As shown, an inserting step S2' is added to the basic structure.

[0064] Below, refer to Figure 3 and Figure 4 Describe each step.

[0065] Cell stack 100 preparation step S1

[0066] This is a step of preparing the battery cell stack 100 having the plurality of battery cells 110 stacked, with electrode leads 111 led out from the plurality of battery cells 110 .

[0067] The battery cell 110 includes an electrode assembly formed by stacking electrodes and separators, etc., an electrode lead 111 electrically connected to the electrode assembly, a case that closes and seals the electrode assembly so that the electrode lead 111 is led outward, and an electrolyte filled with the electrode assembly in the case.

[0068] The battery cell 110 of the present invention includes a pair of electrode leads 111 having different polarities.

[0069] The battery cell stack 100 includes a plurality of battery cells 110 stacked in one direction such that electrode leads 111 may be disposed side by side at a predetermined distance.

[0070] Busbar frame 200 preparation step S2

[0071] This is a step of preparing the bus bar frame 200 having the lead connection part 200 p including a pair of lead slits 230 spaced apart by a predetermined distance.

[0072] The bus bar frame 200 is provided with bus bars 210 which may be electrically connected to the electrode leads 111 of the battery cell stack 100 .

[0073] The bus bar frame 200 is coupled to the cell stack 100 to fix the cell stack 100 , and simultaneously supports rear surfaces of the electrode leads 111 so that the electrode leads 111 drawn out from the cell stack 100 can be fixed to the bus bars 210 .

[0074] Figure 5 is a perspective view of a busbar frame 200 of the present invention, Figure 6 yes Figure 5 A horizontal cross-sectional view of the busbar frame 200, and Figure 7 yes Figure 6 Floor plan.

[0075] The lead connection portion 200 p includes a pair of lead slits 230 and an insertion groove 220 formed between the lead slits 230 .

[0076] The bus bar frame 200 may have a plurality of lead connection parts 200 p formed to match the number of electrode leads 111 of the cell stack 100 coupled thereto.

[0077] The lead slit 230 is opened to allow the electrode lead 111 to pass therethrough.

[0078] The lead slit 230 is formed in a shape through which the electrode lead 111 of the cell stack 100 coupled to the busbar frame 200 may pass.

[0079] The lead slit 230 of the present invention is formed to extend along the short width direction of the busbar frame 200 .

[0080] The insertion groove 220 is formed in a shape recessed at a certain depth in the thickness direction of the busbar frame 200 .

[0081] The insertion groove 220 allows the busbar frame 200 to avoid direct contact with the heat generated by welding, and can also serve as a migration path for gases, byproducts, etc. generated by welding. In particular, in the present invention, the insertion groove 220 becomes a region into which the welding prevention rod 310 is inserted, which is used to protect the surface of the busbar frame 200 from the influence of welding heat.

[0082] The insertion groove 220 is formed to extend along the longitudinal direction of the lead slit 230 .

[0083] The bus bar 210 is installed in 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 part 200p may include one bus bar 210.

[0084] The bus bar frame 200 further includes a bus bar 210 insertion portion formed in a shape recessed in a thickness direction of the bus bar frame 200 , into which the bus bar 210 may be inserted.

[0085] The bus bar 210 insertion portion may be formed at an end of the insertion groove 220. That is, the bus bar 210 insertion portion is located at an end of the insertion groove 220 with respect to the short width direction of the bus bar frame 200.

[0086] The insertion portion of the bus bar 210 may also be formed to overlap the insertion groove 220. That is, the insertion portion of the bus bar 210 may be located on an upper portion of the insertion groove 220 with respect to the thickness direction of the bus bar frame 200.

[0087] The bus bar 210 is inserted into the bus bar 210 insertion portion so that the rear surface thereof is supported.

[0088] Insert step S2'

[0089] This is a step of inserting the welding prevention bar 310 into the insertion groove 220 of the bus bar frame 200 .

[0090] During the step of preparing the bus bar frame 200, the welding prevention bar 310 of the present invention may be inserted into the insertion groove 220. Therefore, the step S2 of preparing the bus bar frame 200 of the present invention may include an inserting step S2'.

[0091] The welding prevention bar 310 is used to prevent the bus bar frame 200 from being directly damaged by high temperature heat generated by welding. That is, the welding prevention bar 310 is installed on the surface of the area not affected by welding.

[0092] Preferably, the welding prevention rod 310 comprises a heat-resistant material capable of withstanding the heat generated by welding. For example, the welding prevention rod may comprise carbon steel.

[0093] The method of welding the electrode lead 111 according to the first embodiment of the present invention includes coupling the welding prevention bar 310 to the bus bar frame 200 in the step of preparing the bus bar frame 200 .

[0094] The welding prevention bar 310 is inserted into the insertion groove 220 in such a manner that it can be removed in various forms.

[0095] Figure 8 Is to apply the anti-welding rod 310 to Figure 5 An illustration of the busbar frame 200 , Fig. 9 yes Figure 8 A front view of the busbar frame 200, and Fig.10 yes Figure 8 An enlarged view of a portion of.

[0096] The welding prevention bar 310 includes a bar-shaped protection portion 310 a formed to extend and be inserted into the insertion groove 220 , and a protrusion 310 b having a width longer than that of the protection portion 310 a at an end thereof to be caught at an entrance of the insertion groove 220 .

[0097] The welding prevention bar 310 is coupled to the bus bar frame 200 such that the protection portion 310 a is slidably inserted into the insertion portion of the bus bar frame 200 and the protrusion 310 b is engaged in a protruding shape from the end of the bus bar frame 200 .

[0098] The welding prevention rod 310 is inserted against the bottom of the insertion groove 220 .

[0099] A plurality of welding prevention rods 310 can be independently inserted into the desired insertion slots 220, such as Figure 8 and Fig. 9 As shown, or may be coupled to one protection rod frame 300 and inserted into each insertion groove 220 at the same time.

[0100] Fig.11 An anti-weld bar 310 is shown coupled to the protection bar frame 300 .

[0101] The welding prevention bar 310 is provided in plural at the end of the protection bar frame 300 . It is configured to be able to reciprocate forward and backward toward the bus bar frame 200 . Specifically, the protrusion 310 b of the welding prevention bar 310 is coupled to the end of the protection bar frame 300 .

[0102] A plurality of welding prevention bars 310 coupled to the protection bar frame 300 are provided on one side of the protection bar frame 300 , all facing in one direction.

[0103] Each of the welding prevention bars 310 is spaced apart at a predetermined distance at the end of the protection bar frame 300, such as Fig.11 shown.

[0104] Each of the welding prevention bars 310 is located at an end of the protection bar frame 300 and corresponds to the interval of the insertion groove 220 of the bus bar frame 200. That is, the position of each welding prevention bar 310 coupled to the protection bar frame 300 is affected by the interval of the insertion groove 220.

[0105] Preferably, the length of the thickness of the welding prevention bar 310 used in the electrode lead 111 welding method of the present invention is shorter than the depth of the insertion groove 220. Here, if the length of the thickness of the welding prevention bar 310 is the same as or longer than the depth of the insertion groove 220, when the welding prevention bar 310 moves by sliding in the insertion groove 220, there may be a problem of contact with the electrode lead 111.

[0106] Join step S3

[0107] This is a step of coupling 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 .

[0108] A plurality of electrode leads 111 led out to one side of the cell stack 100 are inserted through a plurality of lead slits 230 formed in the busbar frame 200 .

[0109] At least one lead slit 230 is penetrated by at least one electrode lead 111 .

[0110] The pair of lead slits 230 included in the lead connection portion 200 p are each penetrated by the electrode leads 111 of different polarities.

[0111] Bending step S4

[0112] This is a step of bending the electrode leads 111 passing through the lead slits 230 of the lead connection portion 200 p so as to overlap the electrode leads 111 toward each other.

[0113] Fig.12 A portion of the bus bar frame 200 where the electrode lead 111 is bent is shown.

[0114] The electrode leads 111 vertically penetrating the lead slits 230 are bent at almost a right angle and overlap each other to be supported on the front surface of the bus bar frame 200 .

[0115] Fig.13 yes Fig.12 FIG. 2 is a cutaway sectional view of a portion of a busbar frame 200 .

[0116] The electrode lead 111 welding method of the present invention is characterized in that the welding prevention rod 310 is spaced apart from the rear surface of the electrode lead 111 by a predetermined distance and does not contact each other. Fig.13 In other words, the rear surface of the bent electrode lead 111 is preferably supported only by the busbar frame 200. In this case, as shown in FIG. Fig.13 As shown, the rear surface of the bent electrode lead 111 is connected by contacting the front surface of the bus bar 210 .

[0117] A welding filler 400 melted by welding may be interposed between the overlapped pair of electrode leads 111 and the insertion groove 220 of the bus bar frame 200 .

[0118] Fig.14 A partial cross-section of the busbar frame 200 with the weld filler 400 applied is shown.

[0119] The welding filler 400 may be in a plate shape and may be bent at both ends toward the bus bar frame 200, as shown in FIG. Fig.14 shown.

[0120] Both ends of the bent solder filler 400 may be respectively inserted into the lead slit 230 of the lead connection part 200 p .

[0121] Welding step S5

[0122] This is a step of welding the overlapped pair of electrode leads 111 .

[0123] The welding may be performed by laser welding.

[0124] The temperature of heat generated in the welding area by welding is 2000° C. or higher.

[0125] The electrode leads 111 may be joined together by welding, or the electrode leads 111 and the bus bars 210 may be joined together by welding.

[0126] Remove step S6

[0127] The electrode lead 111 welding method of the present invention may further include a step of removing the welding prevention rod 310 inserted in the insertion groove 220 .

[0128] Since the welding prevention bars 310 have no additional purpose other than protecting the bus bar frame 200 from welding, it is desirable to remove them to reduce the weight of the battery cell 110 assembly.

[0129] Therefore, the inserted welding prevention bar 310 , or the welding prevention bar 310 and the protection bar frame 300 are retracted and removed from the bus bar frame 200 .

[0130] Fig.15 is a simplified representation of the process of removing the anti-weld bar 310 after welding.

[0131] The welding prevention bar 310 is coupled in close contact with the bottom of the insertion groove 220 to protect the bottom of the insertion groove 220 from welding heat. In this case, the welding prevention bar 310 is not joined to the electrode lead 111, the welding filler 400, etc. by welding.

[0132] Reference Fig.15 After the welding is completed, the welding prevention rod 310 is separated from the insertion groove 220 and removed.

[0133] (Second Embodiment)

[0134] The step of inserting the welding prevention rod 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.

[0135] Fig.16 1 is a flowchart of a method for welding an electrode lead 111 according to a second embodiment of the present invention. Fig.17 The present invention shows a method of using the battery cell stack 100 and the bus bar frame 200. Fig.16 Some steps in the flowchart.

[0136] The electrode lead 111 welding method according to the second embodiment of the present invention basically includes a cell stack 100 preparation step S1 , a busbar frame 200 preparation step S2 , a coupling step S3 , a bending step S4 , and a welding step S5 , wherein an inserting step S4 ′ is added to the basic configuration.

[0137] The electrode lead 111 welding method according to the second embodiment of the present invention is different from the electrode lead 111 welding method according to the first embodiment in that the welding prevention bar 310 is not prepared by inserting it into the insertion groove 220 in the preparation step of the bus bar frame 200. That is, the welding prevention bar 310 is inserted in a step immediately before each welding step.

[0138] Reference Fig.16 In the step of bending the electrode lead 111 , the welding prevention rod 310 is inserted into the insertion groove 220 .

[0139] However, the thickness length of the welding prevention bar 310 is shorter than the depth of the insertion groove 220 , so that the bent electrode lead 111 does not contact the welding prevention bar 310 during the process of slidingly inserting the welding prevention bar 310 into the insertion groove 220 .

[0140] The electrode lead 111 welding method according to the second embodiment of the present invention may further include, as in the first embodiment, a step in which the welding prevention bar 310 inserted in the insertion groove 220 is removed.

[0141] Since the welding prevention bars 310 have no additional purpose other than protecting the bus bar frame 200 from welding, it is desirable to remove them to reduce the weight of the battery cell 110 assembly.

[0142] Therefore, the inserted welding prevention bar 310 , or the welding prevention bar 310 and the protection bar frame 300 are retracted and removed from the bus bar frame 200 .

[0143] The welding prevention bar 310 is coupled in close contact with the bottom of the insertion groove 220 to protect the bottom of the insertion groove 220 from welding heat. In this case, the welding prevention bar 310 is not joined to the electrode lead 111 and the welding filler 400 by welding.

[0144] After welding is completed, the welding prevention bar 310 is separated from the insertion groove 220 and removed.

[0145] The present invention is described in more detail above with reference to the accompanying drawings and embodiments. However, it should be understood that the configuration shown in the accompanying drawings or embodiments described herein is only one embodiment of the present invention and does not represent all technical concepts of the present invention, and various equivalents and modifications that can replace them when submitting this application may exist.

[0146] [reference numerals]

[0147] 1: (Prior art) battery cell assembly

[0148] 10: (Prior art) Battery stack

[0149] 11: (Prior Art) Battery Cell

[0150] 12: (Prior Art) Electrode Lead

[0151] 20: (Prior Art) Busbar Frame

[0152] 21: (Prior Art) Bus Bar

[0153] 100: Battery cell stack

[0154] 110: Battery Cell

[0155] 111: Electrode lead

[0156] 200: Busbar frame

[0157] 200p: Lead connection part

[0158] 210: Busbar

[0159] 220: Insert slot

[0160] 230: Lead Slit

[0161] 300: Protection bar frame

[0162] 310: Anti-welding rod

[0163] 310a: Protection Department

[0164] 310b: protrusion

[0165] 400: Welding filler

[0166] S1: Cell stack preparation steps

[0167] S2: Busbar frame preparation step

[0168] S3: Join Step

[0169] S4: Bending Step

[0170] S2', s4': Insertion step

[0171] S5: Welding Step

[0172] S6: Removal Steps

[0173] W: Welding

Claims

1. An electrode lead welding method for welding electrode leads of a battery cell assembly composed of multiple battery cells, the electrode lead welding method comprising the following steps: preparing a battery cell stack in which a plurality of battery cells are stacked and electrode leads are led out from them; A busbar frame provided with a lead connection portion including a pair of lead slits spaced apart by a predetermined distance is prepared coupling the cell stack and the busbar frame so that the electrode leads of the cell stack are inserted through the lead slits; bending the electrode leads passing through the lead slits of the lead connection portion so that the electrode leads overlap toward each other; and A pair of overlapping electrode leads are welded, wherein The lead connection portion includes an insertion groove between a pair of lead slits, wherein The method further comprises the following steps: before the welding step, inserting the welding prevention rod into the insertion groove, wherein The welding prevention bar is inserted into the insertion groove to be spaced apart from a rear surface of the electrode lead by a predetermined distance.

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 a longitudinal direction of the lead slit.

4. The electrode lead welding method according to claim 1, wherein The busbar frame includes a plurality of lead connection parts.

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

6. The electrode lead welding method according to claim 5, wherein The bus bar frame includes a bus bar insertion portion supporting a rear surface of the bus bar, wherein The bus bar insertion portion is located at an end of the insertion groove with respect to a short width direction of the bus bar frame, and The bus bar insertion portion is located on an upper portion of the insertion groove with respect to a thickness direction of the bus bar frame.

7. The electrode lead welding method according to claim 1, wherein The lead slit is penetrated by at least one electrode lead.

8. The electrode lead welding method according to claim 1, wherein A pair of lead slits included in the lead connection portion are respectively penetrated by electrode leads of different polarities.

9. The electrode lead welding method according to claim 1, wherein The temperature of the heat generated by the welding is 2000°C or higher, wherein The welding prevention rod includes a heat-resistant material capable of withstanding heat generated from the welding.

10. The electrode lead welding method according to claim 1, wherein The welding prevention rod is provided in plurality at the end of the protection rod frame so as to be able to reciprocate forward and backward toward the busbar frame, wherein Each of the welding prevention bars is spaced apart by a predetermined distance at an end of the protection bar frame.

11. The electrode lead welding method according to claim 10, wherein Each of the welding prevention bars is located at an end of the protection bar frame and corresponds to an interval of the insertion groove in the bus bar frame.

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

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

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

15. The electrode lead welding method according to claim 1, wherein A plate-shaped welding filler melted by the welding is interposed between the overlapped pair of electrode leads and the insertion groove in the bus bar frame.

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