Laser welding fixtures, laser welding systems, and welding methods using these fixtures.

Abstract

The invention relates to a laser welding fixture applicable to a battery cell assembly comprising multiple stacked battery cells and a side frame covering at least part of multiple battery cells, in which two adjacent conductors are bent and welded, and the laser welding fixture comprises: a support frame constructed to allow the battery cell assembly to be placed within it; and a protective fixture positioned between two adjacent conductors.

Description

Laser welding jig, laser welding system and welding method using the same

[0001] The present invention relates to a laser welding jig, a laser welding system, and a welding method using the same.

[0002] Secondary batteries, which can be recharged and discharged, are widely used in mobile devices such as digital cameras, mobile phones, and laptops. They have recently attracted attention as an energy source for electric vehicles and energy storage systems (ESS). Meanwhile, as electric vehicles and ESS demand large capacity and high output, medium- to large-sized battery devices, such as battery modules housing multiple secondary batteries within a housing or battery packs comprising multiple battery modules, are becoming widely used.

[0003] Since mid- to large-sized battery devices are preferably manufactured with the smallest possible size and weight, square and pouch-shaped battery cells, which can be stacked with high integration and have a small weight-to-capacity ratio, are primarily used as battery cells (unit cells). In particular, pouch-shaped battery cells, which utilize aluminum laminate sheets as external components, have recently attracted significant attention due to their advantages, including light weight, low manufacturing costs, and ease of shape modification.

[0004] Meanwhile, these medium and large-sized battery devices can be formed by assembling multiple battery cells, in which case the multiple battery cells must be electrically connected.

[0005] Previously, the leads of adjacent battery cells were welded on a bus bar, but the metal bus bar had disadvantages in terms of the weight and cost of the battery pack.

[0006] Therefore, there is a need to develop a laser welding jig configured to omit a busbar and a laser welding method using the same.

[0007] The present invention was created in consideration of the above-described problems, and its primary purpose is to provide a laser welding jig configured to omit a bus bar in a laser welding process for electrical connection of a battery cell lead.

[0008] A laser welding jig according to one embodiment of the present invention is a laser welding jig applied to a battery cell assembly in which two adjacent leads are bent and welded, including a plurality of stacked battery cells and a side frame covering at least a portion of the plurality of battery cells, and may include a pallet configured to allow the battery cell assembly to be seated and a protective jig disposed between the two adjacent leads.

[0009] The protective jig can be positioned at the rear of two adjacent leads.

[0010] The protective jig may contain carbon steel.

[0011] The protective jig can have one end connected to the pallet to form a fixed end, and the other end can form a free end.

[0012] The pallet may include a plate portion on which a battery cell assembly is mounted; a pressing portion configured to pressurize the battery cell assembly mounted on the plate portion; and a connecting portion extending from the plate portion to which a protective jig is connected.

[0013] The connection member may be configured to be vertically spaced or accessible from one side of the battery cell assembly having the side frame.

[0014] It may further include an insulating block connecting the connecting portion and the protective jig.

[0015] The insulating block may have a sliding joint configured to allow the protective jig to move in a direction parallel to the stacking direction of the plurality of battery cells.

[0016] The plate portion may further include a fixing portion configured to fix a side frame of the battery cell assembly.

[0017] A laser welding system according to one embodiment of the present invention may further include a laser welding jig; and a moving part configured to move a battery cell assembly.

[0018] The pallet may have a movable portion receiving portion on which at least a portion of the battery cell assembly is unsettled so that the movable portion can be received.

[0019] A laser welding method according to one embodiment of the present invention is a laser welding method for joining leads of a plurality of battery cells using a laser welding jig, the method including: a step of placing a battery cell assembly on a laser welding jig; a step of bending leads of a plurality of battery cells; and a step of welding the bent leads.

[0020] In the step of mounting the battery cell assembly on the laser welding jig, the battery cell assembly can be mounted by a moving part configured to move the battery cell assembly.

[0021] In the step of mounting the battery cell assembly on the laser welding jig, the battery cell assembly can be fixed by a fixing member provided on the laser welding jig.

[0022] The side frame may include a protection jig storage portion for accommodating a protection jig; a first support portion provided on one side of the protection jig storage portion and supporting a lead of a battery cell; and a second support portion provided on the other side of the protection jig storage portion and supporting a lead of a battery cell.

[0023] In the step of bending the leads of the plurality of battery cells, the bent leads can be bent to include a first region supported by the first support and a second region supported by the second support.

[0024] A pallet of a laser welding jig includes a plate portion on which a battery cell assembly is mounted; a pressing portion configured to pressurize the battery cell assembly mounted on the plate portion; and a connecting portion extending from the plate portion to which a protection jig is connected, wherein the connecting portion can be configured to be vertically spaced from or accessible to one surface of a battery cell assembly having a side frame.

[0025] The welding method may further include, prior to the step of seating the battery cell assembly on the laser welding jig, the step of moving the connecting portion so as to be spaced apart in a vertical direction from one side of the battery cell assembly having the side frame.

[0026] The welding method may further include, after the step of seating the battery cell assembly on the laser welding jig, the step of moving the connecting portion so as to approach vertically one surface of the battery cell assembly having the side frame.

[0027] The welding method may further include, after the step of welding the bent lead, a step of releasing the battery cell assembly from its mounting position by a moving member configured to move the battery cell assembly.

[0028] According to one aspect of the present invention, a battery cell assembly can be protected from welding plasma generated at the rear of the area where laser welding of a bent lead is performed. This is because a protective jig is positioned at the rear of the area where laser welding is performed, thereby preventing welding plasma from damaging the side frame or battery cells. This enables a battery pack configuration that omits busbars, thereby reducing the weight and cost of the battery pack.

[0029] According to another aspect of the present invention, insulation can be satisfied between adjacent protective jigs. Therefore, the welding process can be smoothly performed in any electrical connection relationship between multiple battery cells, including series, parallel, or both. This prevents problems such as short circuits occurring due to battery cells that should not be electrically connected, or failure to satisfy the desired electrical connection relationship, depending on the electrical connection relationship between the multiple battery cells. In addition, a protective jig receiving portion is provided to stably accommodate the protective jig in the insulating block.

[0030] According to another aspect of the present invention, a battery cell assembly can be stably secured to a laser welding jig. Furthermore, it can be easily aligned with a protective jig between the leads of adjacent battery cells.

[0031] According to another aspect of the present invention, by securing the battery cell assembly to the plate portion while moving the connection portion outward, the battery cell assembly can be prevented from being damaged by the protective jig.

[0032] According to another aspect of the present invention, since the protection jig is moved while the battery cell assembly is pressurized by the pressurizing portion, it is easy to align the protection jig to an appropriate position of the battery cell assembly.

[0033] FIG. 1 is a drawing showing a laser welding jig according to one embodiment of the present invention.

[0034] FIG. 2 is a drawing showing a laser welding jig and a battery cell assembly according to one embodiment of the present invention.

[0035] FIG. 3 is a drawing showing a protective jig included in a laser welding jig according to one embodiment of the present invention.

[0036] FIG. 4 is a drawing showing a partial cross-section of a laser welding jig and a battery cell assembly according to one embodiment of the present invention.

[0037] FIG. 5 is a partially enlarged view of a laser welding jig according to another embodiment of the present invention.

[0038] FIG. 6 is a partially enlarged view of a laser welding jig according to another embodiment of the present invention.

[0039] FIG. 7 is a drawing showing a partial cross-section of a laser welding jig and a battery cell assembly according to one embodiment of the present invention.

[0040] FIG. 8 is a drawing showing a state before a battery cell assembly is mounted on a laser welding jig according to another embodiment of the present invention.

[0041] FIG. 9 is a drawing showing the appearance of a battery cell assembly after it has been mounted on a laser welding jig according to another embodiment of the present invention.

[0042] FIG. 10 is a drawing showing a bending of a lead of a battery cell assembly mounted on a laser welding jig according to one embodiment of the present invention.

[0043] FIG. 11 is a drawing showing a state in which a battery cell assembly is released from a laser welding jig according to another embodiment of the present invention.

[0044] FIG. 12 is a drawing showing a state in which a lead of a battery cell assembly mounted on a laser welding jig according to one embodiment of the present invention is laser welded.

[0045] FIG. 13 is a drawing showing a bent state of a lead of a battery cell assembly mounted on a laser welding jig according to another embodiment of the present invention.

[0046] FIG. 14 is a drawing showing a laser welding jig according to another embodiment of the present invention.

[0047] FIG. 15 is a drawing showing a state before a battery cell assembly is mounted on a laser welding jig according to another embodiment of the present invention.

[0048] FIG. 16 is a drawing showing the appearance of a battery cell assembly after it has been mounted on a laser welding jig according to another embodiment of the present invention.

[0049] Before going into the detailed description of the present invention, it should be noted that the terms and words used in this specification and claims should not be interpreted as limited to their usual or dictionary meanings, but should be interpreted with meanings and concepts that conform to the technical idea of ​​the present invention based on the principle that the inventor can appropriately define the concept of the term in order to explain his own invention in the best way. Therefore, the embodiments described in this specification and the configurations illustrated in the drawings are only the most preferred embodiments of the present invention and do not represent all of the technical idea of ​​the present invention. Therefore, it should be understood that there may be various equivalents and modified examples that can replace them at the time of this application.

[0050] The same reference numbers or symbols used in each drawing attached to this specification represent parts or components that perform substantially the same functions. For convenience of explanation and understanding, the same reference numbers or symbols may be used in different embodiments. In other words, even if components with the same reference numbers are depicted in multiple drawings, they do not necessarily represent a single embodiment.

[0051] In the following description, singular expressions include plural expressions unless the context clearly indicates otherwise. Terms such as "comprises" or "comprises" should be understood to indicate the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification, but do not preclude the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0052] In addition, in the description below, expressions such as top, upper, lower, lower, side, front, and rear are expressed based on the direction shown in the drawing, and it is noted in advance that they may be expressed differently if the direction of the object in question changes.

[0053] Additionally, terms including ordinal numbers, such as "first," "second," etc., may be used in this specification and claims to distinguish between components. These ordinal numbers are used to distinguish identical or similar components from each other, and the use of these ordinal numbers should not be interpreted in a limited manner. For example, components associated with these ordinals should not be interpreted in a restricted manner, such as in the order of use or arrangement, based on their numbers. If necessary, each ordinal number may be used interchangeably.

[0054] Hereinafter, embodiments of the present invention will be described with reference to the attached drawings. However, the spirit of the present invention is not limited to the presented embodiments. For example, those skilled in the art who understand the spirit of the present invention may propose other embodiments within the spirit of the present invention by adding, modifying, or deleting components, etc., but such embodiments will also be considered to be within the spirit of the present invention. The shapes and sizes of elements in the drawings may be exaggerated for clarity.

[0055] FIG. 1 is a drawing showing a laser welding jig (1) according to one embodiment of the present invention. FIG. 2 is a drawing showing a laser welding jig (1) and a battery cell assembly (100) according to one embodiment of the present invention. FIG. 3 is a drawing showing a protection jig (20) included in the laser welding jig (1) according to one embodiment of the present invention. FIG. 4 is a drawing showing a partial cross-section of a laser welding jig (1) and a battery cell assembly (100) according to one embodiment of the present invention.

[0056] Referring to FIGS. 1 to 4, a laser welding jig (1) according to the present invention may include a pallet (10) and a protective jig (20).

[0057] Before describing the laser welding jig (1), a description will be given of the battery cell assembly (100) mounted on the laser welding jig (1).

[0058] A battery cell assembly (100) may include a plurality of battery cells (110) and a side frame (120). The battery cell assembly (100) may be formed by stacking a plurality of battery cells (110) in one direction. The battery cell assembly (100) may not include a bus bar.

[0059] The battery cell (110) may be a pouch cell. The battery cell (110) may include an electrode assembly, an electrolyte, and a pouch outer case. The electrode assembly may be formed by folding or winding a laminate including a first electrode, a second electrode, and a separator. The battery cell (110) may include a first lead electrically connected to a first electrode of the electrode assembly and protruding outward from the pouch outer case, and a second lead electrically connected to a second electrode of the electrode assembly and protruding outward from the pouch outer case. The first lead and the second lead may protrude in both directions as illustrated in FIG. 2, but may also protrude in one direction. The first lead may be made of copper. The first lead may have a negative electrode. The second lead may be made of aluminum. The second lead may have a positive electrode.

[0060] The side frame (120) can cover at least a portion of a plurality of battery cells (110). The side frame (120) can include a plurality of structures (supporting members and protective jig receiving members, which will be described later) corresponding to the number of leads (L) of the battery cells (110). For example, each structure of the side frame (120) can be provided corresponding to two adjacent leads (L).

[0061] Two adjacent leads (L) can be bent by overlapping each other, and at this time, the side frame (120) can be configured with supports on both sides to support the bent leads (L) by contacting the bent leads (L). Depending on the support structure of the supports, the leads (L) can be bent consistently, and the occurrence of a gap between the overlapping leads (L) can be minimized.

[0062] A protective jig receiving portion for receiving a protective jig (20) may be provided between the two protrusions of the side frame (120), and the protective jig receiving portion may be opened on at least one side for insertion of the protective jig (20). The lead (L) of the battery cell (110) may penetrate the receiving space of the side frame (120) in its longitudinal direction.

[0063] When the first and second leads of the battery cell (110) protrude in different directions (e.g., a bidirectional cell), a plurality of side frames (120) may be provided to cover different sides of the plurality of battery cells (110). However, unlike as illustrated in FIG. 2, when the first and second leads of the battery cell (110) protrude in one direction (e.g., a unidirectional cell), the side frame may cover only one side of the battery cell assembly (100).

[0064] The side frame (120) may include an electrically insulating material.

[0065] The pallet (10) may be configured to allow a battery cell assembly (100) to be installed. The pallet (10) may be configured to support the battery cell assembly (100) in a direction perpendicular to the direction in which a plurality of battery cells (110) are stacked.

[0066] A protection jig (20) may be provided between leads (L) of adjacent battery cells among a plurality of battery cells (110). The protection jig (20) may be connected to a pallet (10). The protection jig (20) may be positioned at the rear of the leads (L) of the bent battery cells (i.e., in a direction facing the inside of the battery cell assembly (100).

[0067] According to this configuration of the present invention, the battery cell assembly (100) can be protected from welding plasma generated at the rear of the area where laser welding of the bent lead (L) is performed. This is because the positioning of the protection jig (20) at the rear of the area where laser welding of the bent lead (L) is performed prevents the welding plasma from damaging the side frame (120) or the battery cell (110). In particular, even if the battery pack does not include a bus bar, the provision of the protection jig (20) to the laser welding jig (1) can prevent the battery cell assembly (100) from being damaged during the welding process of the bent lead (L). Therefore, electrical connection of a plurality of battery cells (110) in which bus bars are omitted in the battery pack is possible, which can lead to weight and cost reduction of the battery pack.

[0068] Referring back to FIG. 1, the palette (10) may include a plate portion (13), a pressure portion (15), and a connecting portion (17).

[0069] The plate portion (13) provides a mounting area for the battery cell assembly (100). The plate portion (13) can support the battery cell assembly (100) in a direction perpendicular to the direction in which the plurality of battery cells (110) are stacked.

[0070] The pressurizing portion (15) can pressurize the battery cell assembly (100) mounted on the plate portion (13). The pressurizing portion (15) can pressurize the side of the battery cell assembly (100) in a direction parallel to the direction in which the plurality of battery cells (110) are stacked. In particular, the pressurizing portion (15) can pressurize both sides of the battery cell assembly (100).

[0071] The pressurization method of the pressurization unit (15) can be manual through the operator's operation, or it can be automatically operated by an electric signal by being connected to an actuator.

[0072] The connecting portion (17) can be extended from the plate portion (13) at one end and a protective jig (20) can be connected at the other end. The connecting portion (17) can be connected to the lower end of the protective jig (20).

[0073] Referring back to FIGS. 1 to 4, the protective jig (20) may have a cantilever beam shape. One end of the protective jig (20) may be connected to the pallet (10) to form a fixed end (21). The other end of the protective jig (20) may form a free end (23). The lower end of the protective jig (20) may be connected to the pallet (10) by a bolt. Since the protective jig (20) is erected in a direction perpendicular to the ground, it can be prevented from sagging due to its own weight. The protective jig (20) is damaged due to the laser welding process and must be replaced after a certain number of laser processes. Therefore, according to this configuration, since the protective jig (20) does not sag due to its own weight, the replacement process of the protective jig (20) is easy and the replacement cycle can be extended. In addition, since the protective jigs (20) are individually provided between the leads (L) of adjacent battery cells among a plurality of battery cells (110), each protective jig (20) can be individually replaced.

[0074] The protective jig (20) is provided in a roughly stick shape and can penetrate the space between two leads (L) of two adjacent battery cells. The free end of the protective jig (20) is provided to protrude further than one edge of the two bent leads (L) to minimize the possibility of damage to the battery cell (110) due to welding.

[0075] The width of the protective jig (20) may vary depending on the location. For example, the fixed end of the protective jig (20) may be formed with a wider width than other parts to ensure smooth connection with the pallet (10), thereby increasing the area in contact with the pallet (10) and securing rigidity.

[0076] The other end of the protective jig (20) can be chamfered. Even if the protective jig (20) comes into contact with the battery cell assembly (100) during the process of mounting and dismounting the battery cell assembly (100) on the laser welding jig (1), damage caused thereby can be minimized.

[0077] The protective jig (20) may include carbon steel, for example, S45C material. The protective jig (20) may additionally include an insulating coating layer on the outside to prevent short circuiting of the battery cell (110).

[0078] Referring again to FIG. 4, the protective jig (20) may be positioned so as not to touch the bent lead (L). The clearance between the protective jig (20) and the bent lead (L) may be approximately twice or more the sum of the thicknesses of the bent and overlapping leads (L). This prevents the lead (L) and the protective jig (20) from being fused together during the laser welding process.

[0079] The protective jig (20) may be at least 2.5 times the sum of the thicknesses of the bent and overlapping leads (L). This prevents the protective jig (20) from being thermally deformed by welding plasma.

[0080] The protective jig (20) may be positioned so as not to come into contact with the side frame (120). The clearance between the protective jig (20) and the side frame (120) may be greater than the sum of the thicknesses of the bent and overlapping leads (L). Through this, even if heat caused by the welding plasma is conducted toward the side frame (120) through the protective jig (20), thermal deformation of the side frame (120) can be prevented. In addition, the protective jig (20) can be prevented from coming into contact with the battery cell assembly (100) during the process of mounting and detaching the battery cell assembly (100) on the laser welding jig (1).

[0081] Fig. 5 is a partially enlarged view of a laser welding jig (1) according to another embodiment of the present invention. Fig. 6 is a partially enlarged view of a laser welding jig (1) according to another embodiment of the present invention.

[0082] Referring to FIGS. 5 and 6, the laser welding jig (1) may further include an insulating block (30).

[0083] An insulating block (30) can connect a connecting portion (17) and a protective jig (20). The insulating blocks (30) can be arranged in multiples together with the protective jig (20) along the stacking direction of the battery cell assembly (100). The insulating blocks (30) can be arranged corresponding to the lower portion of the lead (L) of the battery cell.

[0084] The insulating block (30) may be provided with a protective jig receiving portion (31). The protective jig receiving portion (31) may be configured to receive a protective jig (20). The protective jig receiving portion (31) may be a groove formed on one surface of the protective jig (20) so as to be approximately equal to or greater than the thickness, width, and length of the fixed end (21) of the protective jig (20) so as to receive the fixed end (21) of the protective jig (20).

[0085] The insulating block (30) may be provided with a sliding joint (33) configured to allow the protective jig (20) to move in a direction parallel to the stacking direction of the plurality of battery cells (110). The sliding joint (33) is formed on the outer surface of the insulating block (30) and may be a groove extending along the stacking direction of the plurality of battery cells so that a bolt connected to the protective jig (20) can be inserted and moved.

[0086] The connection part where the protection jig (20) and the insulation block (30) are connected on the insulation block (30) may be variable. Referring to Fig. 6, the protection jig (20) may be moved on the insulation block (30) to a desired position, and then the bolt may be inserted into the sliding joint (33) and the nut may be tightened to fix the protection jig (20). However, the movable structure of the insulation block (30) is not limited to this, and for example, a rail may be provided on the insulation block (30) so that the protection jig (20) moves on the rail and the spacing of the protection jig (20) may be adjusted. According to this configuration, it is possible to adjust the spacing of the protection jig (20). The size of the battery cells (110) included in the battery cell assembly (100) may vary depending on the size, voltage, etc., and thus the spacing between the battery cells (110) may vary. In this case, a laser welding jig must be manufactured for each different battery cell assembly, but according to the present invention, by variably adjusting the spacing of the protection jig (1), one laser welding jig can be used for different battery cell assemblies (100).

[0087] According to this configuration of the present invention, insulation can be satisfied between adjacent protection jigs (20). Therefore, the welding process can be smoothly performed in any electrical connection relationship including series, parallel, and all of these between the plurality of battery cells (110). It is possible to prevent problems such as short circuits occurring due to battery cells that should not be electrically connected being connected to each other or failure to satisfy the desired electrical connection relationship depending on the electrical connection relationship between the plurality of battery cells (110). In addition, the protection jig receiving portion (31) is provided so that the protection jig (20) can be stably received in the insulating block (30).

[0088] FIG. 7 is a drawing showing a partial cross-section of a laser welding jig and a battery cell assembly according to one embodiment of the present invention.

[0089] Referring to FIGS. 5 and 7, the laser welding jig (1) may further include a fixing member (P).

[0090] The fixing member (P) may be configured to fix the side frame (120) of the battery cell assembly (100). The fixing member (P) may be in the form of a pin. The fixing member (P) may be fitted into a hole formed in the lower portion of the side frame (120). Through this, the battery cell assembly (100) can be stably fixed to the laser welding jig (1). In addition, the protection jig (20) can be easily aligned between the leads (L) of adjacent battery cells.

[0091] FIG. 8 is a drawing showing the appearance of a battery cell assembly (100) before being mounted on a laser welding jig (1) according to one embodiment of the present invention. FIG. 9 is a drawing showing the appearance of a battery cell assembly (100) after being mounted on a laser welding jig (1) according to one embodiment of the present invention.

[0092] Referring to FIGS. 8 and 9, the laser welding system according to the present invention may further include a moving part (50).

[0093] The moving unit (50) may be configured to move the battery cell assembly (100). The moving unit (50) may move the battery cell assembly (100) while receiving the battery cell assembly (100). The moving unit (50) may include a first part (51) that supports the battery cell assembly (100) at the bottom of the battery cell assembly (100) and a second part (53) that extends from the first part (51) and covers a side of the battery cell assembly (100). The moving unit (50) may be a robotic arm including the first part (51) and the second part (53). The moving unit (50) may include four robotic arms, and may move the battery cell assembly (100) while receiving the battery cell assembly (100) with two robotic arms on each of the two sides of the battery cell assembly (100). The moving part (50) may include a driving part that generates power to move the robot arm. However, the moving part (50) may also be manually moved by a worker, in which case the driving part may not be provided.

[0094] The pallet (10) may be provided with a movable unit receiving portion (11) on which at least a portion of the battery cell assembly (100) is unsettled so that the movable unit (50) can be received. The movable unit receiving portion (11) may be a portion configured to open the battery cell assembly (100) toward the ground. By providing the movable unit receiving portion (11) on the pallet (10), it may be configured so that interference with the movable unit (50) does not occur as the movable unit (50) moves.

[0095] FIG. 10 is a drawing showing a state in which a lead (L) of a battery cell assembly (100) mounted on a laser welding jig (1) according to one embodiment of the present invention is bent. FIG. 11 is a drawing showing a state in which a battery cell assembly (100) is released from a laser welding jig (1) according to another embodiment of the present invention. FIG. 12 is a drawing showing a state in which a lead (L) of a battery cell assembly (100) mounted on a laser welding jig (1) according to one embodiment of the present invention is laser welded. FIG. 13 is a drawing showing a state in which a lead (L) of a battery cell assembly (100) mounted on a laser welding jig (1) according to another embodiment of the present invention is bent.

[0096] Referring again to FIGS. 8 to 13, the laser welding method according to the present invention may include a step of mounting a battery cell assembly (100) on a laser welding jig (1), a step of bending leads (L) of a plurality of battery cells, and a step of welding the bent leads (L).

[0097] The battery cell assembly (100) can be mounted on the laser welding jig (1) from the top toward the bottom of the laser welding jig (1).

[0098] In the step of mounting the battery cell assembly (100) on the laser welding jig (1), the battery cell assembly (100) can be mounted by a moving part (50) configured to move the battery cell assembly (100).

[0099] In the step of mounting the battery cell assembly (100) on the laser welding jig (1), the battery cell assembly (100) can be fixed by a fixing member (P) provided on the laser welding jig (1). A pin-shaped fixing member (P) formed on the plate portion (13) can be inserted into a hole formed at the bottom of the side frame (120) of the battery cell assembly (100) to be fixed. In this process, the battery cell assembly (100) can be pressed or its position adjusted so that the protection jig (20) is positioned between the leads (L) of adjacent battery cells.

[0100] The laser welding method according to the present invention may further include, after the step of welding the bent lead (L), a step of releasing the mounting by a moving part (50) configured to move the battery cell assembly (100).

[0101] The side frame (120) may include a protective jig storage portion (123), a first support portion (125), and a second support portion (127).

[0102] The protection jig storage unit (123) can accommodate the protection jig (20). The first support unit (125) is provided on one side of the protection jig storage unit (123) and can support the lead (L) of the battery cell. The second support unit (127) is provided on the other side of the protection jig storage unit (123) and can support the lead (L) of the battery cell.

[0103] The leads (L) of the plurality of battery cells can be bent toward the side frame (120) according to the electrical connection relationship required in the battery pack. The bent leads (L) can be pressed with a certain pressure while being supported by the first support member (125) and the second support member (127). In the step of bending the leads (L) of the plurality of battery cells, the bent leads (L) can be bent to include a first region (L1) supported by the first support member (125) and a second region (L2) supported by the second support member (127). The bent leads (L) can be stably supported by the two support members.

[0104] The bent and overlapping leads (L) can be joined by laser welding while being pressed toward the side frame (120). A protective jig (20) can be positioned at the rear of the area where the laser welding of the bent leads (L) is performed. The area where the laser welding of the bent leads (L) is performed can be between the first support member (125) and the second support member (127).

[0105] Laser welding can be performed with a power lower than the power at which a hole is drilled in the lead (L) and higher than the power at which a weak weld is produced between the bent leads (L) that is less than the desired weld strength.

[0106] After laser welding is completed, the battery cell assembly (100) can be separated from the laser welding jig (1) by moving from the lower part to the upper part of the laser welding jig (1).

[0107] Fig. 14 is a drawing showing a laser welding jig (1) according to another embodiment of the present invention.

[0108] Referring to Fig. 14, the connecting portion (17) may be configured to be movable in the direction extending from the plate portion (13) to the laser welding jig (1) and in the opposite direction. That is, the protective jig (20) connected to the connecting portion (17) may be configured to be vertically spaced from or approachable to one side of the battery cell assembly (100) having the side frame (120).

[0109] The connecting portion (17) can slide and move through a rail or groove formed in the plate portion (13). The connecting portion (17) is connected to a cylinder and can move by the operation of the cylinder.

[0110] According to this configuration of the present invention, by moving the connecting portion (17) to which the protection jig (20) is connected and the battery cell assembly (100) is seated on the plate portion (13) in an expanded state, and then the protection jig (20) is seated laterally on the battery cell assembly (100), the possibility of interference between the protection jig (20) and the battery cell assembly (100), specifically, the protection jig (20) and the lead (L) can be minimized.

[0111] A pad for swelling absorption, etc. may be provided between the plurality of battery cells (110) constituting the battery cell assembly (100). If such a pad is not pressurized, it may expand and increase in volume. If the battery cell assembly (100) is not pressurized, the position where the protection jig should be provided may change as the pad expands. Therefore, when a movable mechanism is implemented in which the protection jig (20) is inserted laterally into the battery cell assembly (100), there is an advantage in that no interference problem occurs between the protection jig (20) and the battery cell assembly (100) even if the battery cell assembly (100) is placed on the plate portion (13) and then pressurized by the pressurizing portion (15).

[0112] Fig. 15 is a drawing showing the appearance of a battery cell assembly (100) before being mounted on a laser welding jig (1) according to another embodiment of the present invention. Fig. 16 is a drawing showing the appearance of a battery cell assembly (100) after being mounted on a laser welding jig (1) according to another embodiment of the present invention.

[0113] Referring to FIG. 15, the laser welding method may further include a step of moving the connecting portion (17) in a direction in which the connecting portion (17) extends from the plate portion (13). That is, the laser welding method may further include a step of moving the connecting portion (17) so as to be spaced apart in a vertical direction from one surface of the battery cell assembly (100) having the side frame (120) before the step of seating the battery cell assembly (100) on the laser welding jig (1).

[0114] Referring to FIG. 16, the laser welding method may further include a step of moving the connecting portion (17) in the opposite direction to the direction in which the connecting portion (17) extends from the plate portion (13). That is, after the step of seating the battery cell assembly (100) on the laser welding jig (1), the laser welding method may further include a step of moving the connecting portion (17) so as to approach in a vertical direction one surface of the battery cell assembly (100) provided with the side frame (120).

[0115] While the present invention has been described with reference to the accompanying drawings, focusing on preferred embodiments, it will be apparent to those skilled in the art that numerous obvious modifications can be made without departing from the scope of the present invention. Therefore, the scope of the present invention should be construed as encompassing the many examples of such modifications within the scope of the claims.

Claims

1. A laser welding jig applied to a battery cell assembly in which two adjacent leads are bent and welded, comprising a plurality of stacked battery cells and a side frame covering at least a portion of the plurality of battery cells, A pallet configured to allow the above battery cell assembly to be seated; and A protective jig placed between the two adjacent leads; Laser welding jig including.

2. In paragraph 1, The above protective jig is, A laser welding jig characterized by being positioned at the rear of the two adjacent leads.

3. In paragraph 1, The above protective jig is, A laser welding jig characterized by comprising carbon steel.

4. In paragraph 1, The above protective jig is, A laser welding jig characterized in that one end is connected to a pallet to form a fixed end, and the other end forms a free end.

5. In paragraph 1, The above palette is, A plate portion on which the above battery cell assembly is mounted; A pressurizing unit configured to pressurize the battery cell assembly mounted on the plate portion; and A laser welding jig characterized by including a connecting portion extending from the plate portion and to which the protective jig is connected.

6. In paragraph 5, The above connecting part, A laser welding jig characterized in that one side of a battery cell assembly having the side frame is configured to be vertically spaced or accessible.

7. In paragraph 5, A laser welding jig characterized by further comprising an insulating block connecting the above connecting portion and the above protective jig.

8. In paragraph 7, The above insulating block, A laser welding jig characterized in that the above-mentioned protective jig has a sliding joint configured to move in a direction parallel to the stacking direction of the plurality of battery cells.

9. In paragraph 6, The above plate portion, A laser welding jig further characterized by comprising a fixing member configured to fix a side frame of the battery cell assembly.

10. Laser welding jig according to paragraph 1; and A laser welding system further characterized by comprising a moving part configured to move the battery cell assembly.

11. In clause 10, The above palette is, A laser welding system characterized by having a movable portion receiving portion on which at least a portion of the battery cell assembly is unsettled so that the movable portion can be received.

12. A laser welding method for joining leads of multiple battery cells using a laser welding jig according to Article 1, Step of mounting the battery cell assembly on the laser welding jig; A step of bending leads of multiple battery cells; and A welding method characterized by comprising a step of welding a bent lead.

13. In paragraph 12, In the step of mounting the above battery cell assembly on the laser welding jig, A welding method, characterized in that the battery cell assembly is secured by a moving member configured to move the battery cell assembly.

14. In paragraph 12, In the step of mounting the above battery cell assembly on the laser welding jig, A welding method, characterized in that the battery cell assembly is fixed by a fixing member provided on the laser welding jig.

15. In paragraph 12, The above side frame, A protective jig storage section for accommodating the above protective jig; A first support member provided on one side of the above protective jig storage section and supporting the lead of the battery cell; and A welding method characterized in that the battery cell includes a second support member provided on the other side of the protective jig receiving portion and supporting the lead.

16. In paragraph 15, In the step of bending the leads of the above plurality of battery cells, A welding method, characterized in that the bent lead is bent to include a first region supported by the first support member and a second region supported by the second support member.

17. In paragraph 12, The above pallet of the above laser welding jig, A plate portion on which the above battery cell assembly is mounted; A pressurizing unit configured to pressurize the battery cell assembly mounted on the plate portion; and It includes a connecting portion extending from the above plate portion and to which the protective jig is connected, The above connecting part, A welding method characterized in that one side of a battery cell assembly having the side frame is configured to be vertically spaced or accessible.

18. In paragraph 17, The above welding method, Prior to the step of mounting the above battery cell assembly onto the laser welding jig, A welding method further comprising the step of moving the connecting portion so as to be spaced apart in a vertical direction from one surface of the battery cell assembly having the side frame.

19. In paragraph 18, The above welding method, After the step of mounting the above battery cell assembly on the laser welding jig, A welding method further comprising the step of moving the connecting portion so as to approach vertically one surface of the battery cell assembly having the side frame.

20. In paragraph 12, The above welding method, After the step of welding the above bent lead, A welding method further comprising a step of releasing the mounting of the battery cell assembly by a moving member configured to move the battery cell assembly.

Images