Welding mask and welding method

Abstract

Welding mask and welding method. A welding mask of one embodiment of the present invention includes a welding mask body provided with a laser passage portion and covering an open portion of one side of a case of a battery cell, a laser irradiated to the inside of the case of the battery cell being able to pass through the laser passage portion, and an insertion guide provided with a hollow structure, connected to the laser passage portion, and inserted into a winding center hole of an electrode assembly housed in the inside of the case.

Description

Technical Field

[0001] This invention relates to welding masks and welding methods. Background Technology

[0002] In the manufacturing of battery cells, ultrasonic welding is used, for example, in the bonding of electrode assemblies to current collectors and the bonding of current collectors to terminals. Figure 1 As shown, ultrasonic welding is a welding method in which the workpiece 3 is separated by an ultrasonic welding head 1 and an anvil 2 on both sides, and welding is performed by the vibration of the ultrasonic welding head 1.

[0003] Reference Figure 2 In battery cell 4, when it is desired to weld the current collector 3a and terminal 3b located on the closed side of the battery can 5 opposite to the open portion formed on one side of the battery can 5, the welding nozzle of the ultrasonic welding head 1 needs to be inserted through the take-up center hole of the electrode assembly 6. As a result, the extension length of the welding nozzle of the welding head 1 can only increase, which can cause the welding nozzle of the ultrasonic welding head 1 to bend or break during ultrasonic welding.

[0004] Furthermore, when vibrations for ultrasonic welding are applied in the narrow space within the coiling center hole of the electrode assembly 6, the electrode assembly 6 is damaged due to interference between the inner wall surface of the coiling center hole and the ultrasonic welding head 1.

[0005] Thus, in order to weld the workpiece 3 located on the closed side of the battery can 5, a welding tool needs to be inserted through the take-up center hole of the electrode assembly 6. Therefore, there are many limitations when welding, and this difficulty exists not only in the case of ultrasonic welding, but also in the case of resistance welding.

[0006] With this in mind, it is conceivable that a laser welding scheme could be performed even without inserting the welding tool through the take-up center hole of the electrode assembly 6. However, there are limitations in such laser welding.

[0007] That is, in such Figure 2When laser welding is applied to the battery cell 4 shown to weld the workpiece 3 located on the closed side of the battery can 5, it is necessary to prevent the inner wall surface of the winding center hole from contacting the laser as the laser passes from the inlet of the narrow-width electrode assembly 6 to near the outlet. Furthermore, if welding spatter, welding fumes, or other foreign matter generated during laser welding are scattered onto the inner wall surface of the electrode assembly 6, physical damage to the electrode assembly 6 may occur. Additionally, short circuits may occur inside the battery cell 4 due to metallic foreign matter. Therefore, a solution is needed to prevent damage to the electrode assembly 6 when welding the workpiece 3 located inside the battery cell 4 using laser welding.

[0008] On the other hand, during laser welding, it is necessary to remove the oxygen environment near the workpiece 3. Therefore, a solution is needed where the purge gas used to remove the oxygen environment can easily flow into the vicinity of the workpiece during laser welding.

[0009] Furthermore, when welding the workpiece 3 using laser welding, if foreign matter generated during the welding process is not properly removed, interference from the foreign matter and the laser can prevent proper alignment of the laser focus, making welding difficult. Therefore, a solution is needed that can properly remove foreign matter generated during laser welding. Summary of the Invention

[0010] The problem that the invention aims to solve

[0011] The present invention was developed in view of the above-mentioned problems, and its purpose is to prevent damage to electrode components when welding the welded body located inside the battery cell by laser welding.

[0012] In another aspect, the object of the present invention is to facilitate the flow of purge gas into the vicinity of the workpiece during laser welding in order to remove the oxygen environment near the workpiece.

[0013] In another aspect, the object of the present invention is to properly remove foreign matter generated when welding the workpiece located inside the battery cell by laser welding.

[0014] However, the technical problems to be solved by the present invention are not limited to the above-mentioned problems. Those skilled in the art can clearly understand other problems not mentioned herein from the following description of the invention.

[0015] Methods for solving problems

[0016] To address the aforementioned issues, one embodiment of the present invention provides a welding mask comprising: a welding mask body having a laser-passing portion and an open portion covering one side of the housing of a battery cell, wherein laser light irradiating the interior of the housing of the battery cell can pass through the laser-passing portion; and an insertion guide having a hollow structure, connected to the laser-passing portion, and inserted into a take-up center hole of an electrode assembly housed inside the housing.

[0017] The width of the inlet of the laser passage is wider than the width of the outlet.

[0018] The aforementioned insertion guide is inserted through the inlet of the aforementioned take-up center hole and extends to the outlet of the aforementioned take-up center hole located on the opposite side of the aforementioned inlet.

[0019] The aforementioned welding shield body has a gas injection section, which can inject purging gas into the interior of the outer shell through the aforementioned welding shield body.

[0020] The aforementioned insertion guide is configured separately from the inner wall surface of the aforementioned winding center hole.

[0021] The aforementioned welding shield also includes a gas guide that guides the flow of the purging gas toward the gap between the inner wall surface of the aforementioned take-up center hole and the aforementioned insertion guide.

[0022] The aforementioned insertion guide allows purge gas that flows into the space between the inner wall of the aforementioned take-up center hole and the aforementioned insertion guide to flow into the interior.

[0023] The aforementioned insertion guide has at least one air inlet.

[0024] The aforementioned air inlet has a groove extending upwards from the lowest end of the aforementioned insertion guide.

[0025] The aforementioned air inlet is positioned such that it is separated from the bottom of the aforementioned insertion guide by a predetermined distance upwards.

[0026] The aforementioned welding shield also includes a mesh component configured to cover the aforementioned air inlet.

[0027] The lowermost end of the aforementioned insertion guide is positioned separately from the workpiece being welded.

[0028] The aforementioned welding shield also includes a sealing component, which is used to improve the airtightness of the joint between the welding shield body and the outer shell.

[0029] The aforementioned welding shield body also includes a suction section, which communicates with the internal space of the aforementioned insertion guide.

[0030] Furthermore, one embodiment of the welding method of the present invention, as a method for welding a workpiece located inside the casing of a battery cell, includes: a welding mask placement step, i.e., step A, in which a welding mask including a welding mask body and an insertion guide extending downward from the welding mask body is lowered to cover the open portion formed in the casing of the battery cell and the insertion guide is inserted into the take-up center hole of an electrode assembly disposed inside the casing; and a welding step, i.e., step B, in which a laser is irradiated through a laser passage provided in the welding mask body and the insertion guide to weld a workpiece located on the closed portion side of the casing disposed on the opposite side of the open portion.

[0031] The above welding method also includes a gas injection step, namely step C, in which purge gas is injected into the interior of the outer shell through the above welding shield body.

[0032] Step C above is as follows: the purge gas injected into the interior of the housing flows into the space between the inner wall of the take-up center hole and the insertion guide, and then flows into the interior of the insertion guide.

[0033] Step C above consists of the following steps:

[0034] The purging gas that flows in through the space between the inner wall of the winding center hole and the insertion guide flows into the interior of the insertion guide through the air inlet formed in the insertion guide.

[0035] Step C above consists of the following steps:

[0036] The purge gas flows into the interior of the insertion guide through an air inlet formed at the lower end of the insertion guide.

[0037] Step C above consists of the following steps:

[0038] The purging gas that flows in through the space between the inner wall surface of the winding center hole and the insertion guide flows into the interior of the insertion guide through the gap between the lowermost end of the insertion guide and the workpiece to be welded.

[0039] The above welding method also includes step D, which involves sucking out at least one of the foreign matter, including welding spatter and welding fumes, generated inside the insertion guide when welding the workpiece through the welding shield body.

[0040] Step D above consists of the following steps:

[0041] The foreign object is suctioned out through a suction section that is connected to the aforementioned insertion guide.

[0042] Step D above consists of the following steps:

[0043] Suction is performed through a suction section that is connected to the aforementioned laser passage section.

[0044] Invention Effects

[0045] According to one aspect of the invention, damage to electrode assemblies can be prevented when welding a workpiece located inside a battery cell by laser welding.

[0046] According to another aspect of the invention, during laser welding, a purge gas used to remove the oxygen environment near the workpiece can easily flow into the vicinity of the workpiece.

[0047] According to another aspect of the invention, foreign matter generated during the welding of the workpiece located inside the battery cell by laser welding can be appropriately removed.

[0048] However, the advantageous effects derived from the present invention are not limited to those described above, and those skilled in the art will clearly understand from the following embodiments other advantageous effects not mentioned herein. Attached Figure Description

[0049] The accompanying drawings, which are attached to this specification, illustrate preferred embodiments of the invention and, together with the embodiments described below, help to understand the technical concept of the invention. Therefore, the invention is not limited to the matters described in these drawings.

[0050] Figure 1 and Figure 2 This diagram illustrates the process of welding the workpiece inside a battery cell using ultrasonic welding.

[0051] Figure 3 This is a diagram showing the appearance of the welding mask of the present invention.

[0052] Figure 4 This is a diagram showing the internal structure of the assembly formed by combining the battery cell and the welding shield of the present invention.

[0053] Figure 5 This is a diagram used to illustrate an embodiment in which the welding shield body of the present invention includes a gas guide.

[0054] Figure 6 and Figure 7 This is a diagram illustrating an embodiment of the insertion guide of the present invention having an air inlet in the form of a notch formed at its lower end.

[0055] Figure 8 This is a diagram illustrating an embodiment of the insertion guide of the present invention having an air inlet with a hole shape.

[0056] Figure 9 This is a diagram illustrating an embodiment of the welding shield of the present invention having a mesh component configured to cover an air inlet.

[0057] Figure 10 This is a diagram used to illustrate an embodiment of the present invention in which the insertion guide is separated from the welded body by a specified distance.

[0058] Figure 11 and Figure 12 This is a diagram illustrating an embodiment of the welding shield of the present invention having a sealing component.

[0059] Figure 13 This is a diagram used to illustrate an embodiment in which the suction section and the insertion guide of the welding shield provided in this invention are directly connected.

[0060] Figure 14 This diagram illustrates the circulation path of the purge gas and the path for discharging foreign matter generated during welding when the welding shield of the present invention includes a laser-passing section, a purge gas injection section, and a suction section.

[0061] (Symbol Explanation)

[0062] 100: Welding mask; 110: Welding mask body; 111: Laser passage section; 112: Gas injection section; 113: Suction section; 114: Gas guide; 115: Body extension section; 120: Insertion guide; 121: Air inlet; M: Mesh component; G: Sealing component; L: Laser; 200: Battery cell; 210: Electrode assembly; 211: First uncoated section; 212: Second uncoated section; 220: Housing; 230: Current collector (first current collector); 240: Terminal; 250: Current collector (second current collector). Detailed Implementation

[0063] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings. Before proceeding, the terms and words used in this specification and claims should not be limited to their ordinary or dictionary meanings. Given the principle that inventors may appropriately define terms and concepts in order to best illustrate their invention, they should be interpreted as conforming to the meaning and concept of the present invention. Therefore, the embodiments described in this specification and the structures shown in the accompanying drawings are merely one of the most preferred embodiments of the present invention and do not represent the entirety of the present invention's technical concept. It should be understood that at the time of filing this application, various equivalents and modifications could exist that could replace these.

[0064] Before describing the welding mask 100 of the present invention, an exemplary form of a battery cell 200 including an object to be laser welded using the welding mask 100 of the present invention will first be described.

[0065] Figure 3 This is a diagram showing the appearance of the welding mask of the present invention. Figure 4 This is a diagram showing the internal structure of the assembly formed by combining the battery cell and the welding shield of the present invention.

[0066] Reference Figure 3 and Figure 4 In one embodiment of the present invention, a welding mask 100 serves as a tool for laser welding of a workpiece located inside a battery cell 200, descending from the upper part of the battery cell 200 and attaching to the upper end of the battery cell 200. The laser welding process using the welding mask 100 of the present invention can be performed with one side of the outer casing 220 of the battery cell 200 open and unsealed.

[0067] The battery cell 200 described above is, for example, a cylindrical battery cell 200. The battery cell 200 includes an electrode assembly 210, a housing 220, a current collector (first current collector) 230, and terminals 240. The electrode assembly 210 is a jelly-roll type electrode assembly having a centrally formed take-up hole. The housing 220 houses the electrode assembly 210 through an opening formed at its upper end. The current collector (first current collector) 230 is attached to the lower end of the electrode assembly 210. The current collector (first current collector) 230 is attached to a first uncoated portion 211 located at the lower end of the electrode assembly 210. In this case, the current collector (first current collector) 230 is sandwiched between the closed portion of the housing 220, located on the opposite side of the open portion of the housing 220, and the electrode assembly 210.

[0068] The laser welding process using the welding mask 100 of the present invention is a welding process for joining the current collector plate (first current collector plate) 230 and the terminal 240 of the battery cell 200. That is, in the present invention, the welded body includes the current collector plate (first current collector plate) 230 and the terminal 240. The terminal 240 is fixed to the housing 220, for example, by passing through a closed portion at the lower end of the housing 220. In this case, the electrode assembly 210 and the current collector plate (first current collector plate) 230 are inserted into the interior of the housing 220 through the upper open portion of the housing 220, and the current collector plate (first current collector plate) 230 and the terminal 240 are welded by irradiating the current collector plate (first current collector plate) 230 with a laser through the take-up center hole of the electrode assembly 210.

[0069] On the other hand, the battery cell 200 also includes a current collector (second current collector) 250. The current collector (second current collector) 250 is attached to the upper end of the electrode assembly 210. The current collector (second current collector) 250 is attached to a second uncoated portion 212 provided at the lower end of the electrode assembly 210. The current collector (second current collector) 250 has a current collector hole formed at a position corresponding to the winding center hole of the electrode assembly 210 in a manner that does not obstruct the winding center hole of the electrode assembly 210. In this case, for example, after inserting the electrode assembly 210 and the pair of current collectors 230, 250 into the housing 220 through the upper opening of the housing 220, as described above, the current collector (first current collector) 230 and the terminal 240 are welded by irradiating a laser through the winding center hole of the electrode assembly 210.

[0070] The above describes the battery cell 200, including the workpiece, in the laser welding process using the welding mask 100 of the present invention. However, in laser welding using the welding mask 100 of the present invention, the workpiece is not limited to the current collector plate (first current collector plate) 230 and the current collector plate (second current collector plate) 250 of the battery cell 200 having the structure described above. That is, any workpiece that has a take-up center hole formed in the electrode assembly 210 of the battery cell 200 and is located on the exit side of the take-up center hole provided on the opposite side of the entrance of the take-up center hole for laser incidence can be the workpiece for laser welding using the welding mask 100 of the present invention.

[0071] Reference Figure 3 and Figure 4 According to one embodiment of the present invention, the welding mask 100 includes a welding mask body 110 and an insertion guide 120.

[0072] The aforementioned welding mask body 110 includes a laser passage portion 111, through which laser light irradiating the interior of the housing 220 of the battery cell 200 can pass. The welding mask body 110 is configured to cover an opening formed on one side of the housing 220. The aforementioned insertion guide 120 has a hollow structure to allow laser light to pass through its interior. The aforementioned insertion guide 120 is connected to the laser passage portion 111. The interior space of the aforementioned insertion guide 120 communicates with the interior space of the laser passage portion 111. The aforementioned insertion guide 120 is inserted into the take-up center hole of the electrode assembly 210 housed inside the housing 220.

[0073] According to the structure of the welding shield 100 described above, the laser irradiated from the outside of the battery cell 200 passes through the laser passage portion 111 and the insertion guide 120, passes through the take-up center hole of the electrode assembly 210, and reaches the workpiece to be welded. Furthermore, the insertion guide 120 can be used as a shield between the laser and the inner wall surface of the take-up center hole, thus preventing damage to the electrode assembly 210 caused by errors in the installation of the laser irradiation device. In addition, it can prevent foreign objects such as welding spatter and welding fumes generated during laser welding from reaching the inner wall surface of the take-up center hole and causing damage to the electrode assembly 210, and / or short circuits caused by metal foreign objects within the electrode assembly 210.

[0074] The laser passage 111 described above can be a hole extending through the welding mask body 110. The width of the inlet of the laser passage 111 is wider than the width of the outlet. With this structure of the welding mask 100, a laser irradiation device (not shown) can be easily inserted into the laser passage 111. On the other hand, the width of the inlet of the laser passage 111 refers to the maximum width of the inlet of the laser passage 111. Similarly, the width of the outlet of the laser passage 111 refers to the maximum width of the outlet of the laser passage 111. If the inlet and / or outlet of the laser passage 111 are approximately circular, the width of the inlet and / or the width of the outlet can be defined as the inner diameter of the inlet and / or the inner diameter of the outlet.

[0075] The laser passage portion 111 is provided at approximately the center of the welding mask body 110. The laser passage portion 111 is located at a position corresponding to the take-up center hole of the electrode assembly 210 when the upper opening of the outer shell 220 is covered by the welding mask body 110. This structure of the welding mask 100 facilitates preventing the laser light passing through the laser passage portion 111 from reaching the inner wall surface of the insertion guide 120 inserted into the take-up center hole of the electrode assembly 210.

[0076] Reference Figure 4 The insertion guide 120 is inserted through the inlet of the take-up center hole of the electrode assembly 210 and extends to the outlet of the take-up center hole located on the opposite side of the inlet. According to this structure of the welding shield 100, the electrode assembly 210 is protected from damage by the laser and foreign matter generated by laser welding throughout the entire region along the extending direction of the take-up center hole of the electrode assembly 210 (parallel to the Z-axis). The foreign matter generated by welding includes at least one of welding spatter and welding fumes.

[0077] Reference Figure 3 and Figure 4The aforementioned welding shield body 110 includes a gas injection section 112. The gas injection section 112 injects purging gas into the interior of the housing 220 via the welding shield body 110. This structure of the welding shield 100 allows for easy injection of purging gas into the interior of the housing 220. By injecting purging gas into the interior of the housing 220, the oxygen concentration inside the housing 220 of the battery cell 200 can be reduced. During laser welding, reducing the oxygen concentration inside the housing 220 to a certain level prevents internal fires. Furthermore, when purging gas is supplied to the welding area of ​​the workpiece, corrosion caused by oxidation of the workpiece can be prevented.

[0078] The gas injection section 112 described above can be a hole that penetrates the welding shield body 110. For example, a gas injection device (not shown) can be inserted into the gas injection section 112. Multiple gas injection sections 112 are provided, and in this case, the multiple gas injection sections 112 are arranged around the laser passage section 111. For example, N2 gas can be used as the purge gas. However, the type of purge gas is not limited to this, and various inert gases can be used as purge gases.

[0079] Reference Figure 3 and Figure 4 The insertion guide 120 is disposed separately from the inner wall surface of the winding center hole of the electrode assembly 210. For example, when both the winding center hole of the electrode assembly 210 and the insertion guide 120 are approximately cylindrical, the inner diameter of the winding center hole of the electrode assembly 210 is larger than the outer diameter of the insertion guide 120. For example, the inner diameter of the winding center hole of the electrode assembly 210 is approximately in the range of 5 mm to 8 mm, and the outer diameter of the insertion guide 120 is approximately 1 mm to 2 mm smaller than the winding center hole of the electrode assembly 210.

[0080] In this way, with a space separating the inner wall of the take-up center hole of the electrode assembly 210 from the outer peripheral surface of the insertion guide 120, the purge gas flowing into the interior of the housing 220 through the opening is supplied to the workpiece side through the aforementioned space. Thus, the purge gas supplied to the workpiece reduces the oxygen concentration near the workpiece during laser welding.

[0081] Figure 5 This is a diagram used to illustrate an embodiment in which the welding shield body of the present invention includes a gas guide.

[0082] Reference Figure 5The aforementioned welding shield 100 includes a gas guide 114 that guides the flow of purge gas. The gas guide 114 guides the flow of purge gas toward the gap between the inner wall surface of the take-up center hole formed in the electrode assembly 210 and the insertion guide 120.

[0083] In this way, when the welding shield 100 is equipped with the gas guide 114, the purging gas injected into the interior of the housing 220 through the gas injection section 112 is concentratedly supplied to the space between the inner wall of the take-up center hole and the insertion guide 120. Therefore, the oxygen concentration near the workpiece can be reduced more effectively.

[0084] On the other hand, such as Figure 5 As shown, the welding mask body 110 may have a main body extension 115 extending from its lower surface toward the interior space of the housing 220. In this case, the main body extension 115 is configured to be separate from the electrode assembly 210 or the current collector (second current collector) 250 when the welding mask body 110 is in close contact with the upper end of the housing 220. Thus, when the welding mask body 110 has the main body extension 115, the gas guide 114 extends from the outlet of the gas injection section 112 and through the space formed between the main body extension 115 and the current collector (second current collector) 250 or between the main body extension 115 and the electrode assembly 210, extending to the vicinity of the take-up center hole inlet of the electrode assembly 210.

[0085] Figure 6 and Figure 7 This is a diagram used to illustrate an embodiment of the insertion guide of the present invention having an air inlet with a notch formed at its lower end. Figure 8 This is a diagram illustrating an embodiment of the insertion guide of the present invention having an air inlet with a hole shape. Additionally, Figure 9 This is a diagram used to illustrate an embodiment of the welding shield of the present invention having a mesh component configured to cover an air inlet. Figure 10 This is a diagram used to illustrate an embodiment of the present invention in which the insertion guide is separated from the welded body by a specified distance.

[0086] Reference Figure 3 and Figure 4 , Figures 6 to 10 The aforementioned insertion guide 120 allows purge gas that flows into the space between the inner wall of the take-up center hole formed in the electrode assembly 210 and the insertion guide 120 to flow into the interior of the insertion guide 120. Figures 6 to 10 The figure shows an exemplary configuration of such a structure as the insertion guide 120.

[0087] According to the structure of the insertion guide 120 described above, the purge gas flowing into the interior of the housing 220 through the gas injection section 112 flows into the interior of the insertion guide 120 through the space formed between the take-up center hole and the insertion guide 120. Thus, the purge gas can reduce the oxygen concentration in the welding area of ​​the workpiece irradiated by the laser L.

[0088] Reference Figure 6 The insertion guide 120 has at least one air inlet 121. In this case, purge gas flowing in through the space between the inner wall of the winding center hole and the outer peripheral surface of the insertion guide 120 flows into the internal space of the insertion guide 120 through the air inlet 121. The air inlet 121 has, for example, a notching shape extending upwards from the lower end of the insertion guide 120. Thus, with the air inlet 121 formed at the lowermost end of the insertion guide 120, the purge gas flowing into the interior of the insertion guide 120 is concentratedly supplied to the welding area of ​​the workpiece irradiated by the laser L, thereby effectively creating an inert environment in the welding area.

[0089] Reference Figure 7 The aforementioned air inlets 121 are provided in multiple locations. These multiple air inlets 121 are arranged separately from each other around the lower end of the insertion guide 120. Thus, by providing multiple air inlets 121, the purge gas can flow more smoothly into the interior space of the insertion guide 120.

[0090] Reference Figure 8 ,and Figure 6 and Figure 7 In a different configuration than illustrated, the air inlet 121 is positioned a predetermined distance H upward from the lowermost end of the insertion guide 120. In this case, the phenomenon of foreign matter generated during laser welding splashing onto the outside of the insertion guide 120 can be minimized. Multiple air inlets 121 are provided, and in this case, the multiple air inlets 121 are arranged apart from each other along the circumference of the insertion guide 120.

[0091] On the other hand, in such an embodiment, it is preferable to limit the formation height H of the air inlet 121 (i.e., a predetermined distance) to below a certain level. Increasing the formation height H of the air inlet 121 is more advantageous when considering only its function as a protective cover for the insertion guide 120. However, if the formation height H of the air inlet 121 is too high, the purge gas circulation speed may not be able to reach the lowermost end of the insertion guide 120 if the purge gas circulation speed is not reduced to below a certain level. Therefore, if the formation height of the air inlet 121 exceeds a certain level, the purge gas circulation speed must be reduced in order to supply purge gas effectively to the welding area, which leads to a decrease in productivity. Therefore, the air inlet 121 is preferably located at a height approximately 0 to 10 mm above the lowermost end of the insertion guide 120, preferably at a height approximately 0 to 15 mm above the lowermost end, and more preferably at a height approximately 0 to 20 mm above the lowermost end.

[0092] On the other hand, such as Figures 6 to 8 As shown, when the insertion guide 120 of the present invention has an air inlet 121, the lowermost end of the insertion guide 120 contacts the workpiece to be welded. In this case, the insertion guide 120 serves as a shield to prevent foreign matter generated during laser welding from splashing onto the electrode assembly 210 side in all areas except the area where the air inlet 121 is formed, thereby effectively preventing damage to the electrode assembly 210. Of course, the lowermost end of the insertion guide 120 may also be separate from the workpiece to be welded without contact, but in this case, considering the function of the insertion guide 120 as a shield, it is preferable that only a very small gap is formed between the lowermost end of the insertion guide 120 and the workpiece to be welded.

[0093] Reference Figure 9 The welding mask 100 of the present invention (see reference) Figure 4 It also includes a mesh component M. The mesh component M covers the air inlet 121. Thus, with the air inlet 121 covered by the mesh component M, the purge gas flows smoothly into the interior of the insertion guide 120 through the tiny holes formed in the mesh component M, while foreign matter, including welding spatter and / or welding fumes, generated in the welding area inside the insertion guide 120 does not easily flow out to the outside of the insertion guide 120. Therefore, an inert environment in the welding area can be created, and damage to the electrode assembly 210 can be prevented.

[0094] On the other hand, refer to Figure 10The lowermost end of the aforementioned insertion guide 120 is disposed separately from the workpiece to be welded. The aforementioned insertion guide 120 may not have a separate air inlet 121 as described above. In this case, the aforementioned purging gas flows into the interior of the insertion guide 120 only through the gap formed between the lowermost end of the insertion guide 120 and the workpiece to be welded.

[0095] Figure 11 and Figure 12 This is a diagram illustrating an embodiment of the welding shield of the present invention having a sealing component.

[0096] Reference Figure 11 and Figure 12 The welding mask 100 also includes a sealing member G for improving the airtightness of the joint between the welding mask body 110 and the outer casing 220. With the sealing member G, the interior of the outer casing 220 of the battery cell 200 can be sealed during the laser welding process. Therefore, it is possible to prevent the purge gas supplied to the interior of the outer casing 220 from leaking to the outside through the joint interface between the welding mask body 110 and the upper end of the outer casing 220.

[0097] The aforementioned sealing member G is, for example, made of an elastic rubber material. However, the material of the sealing member G is not limited to this; any material that improves airtightness when sandwiched between objects can be used as the sealing member G of the present invention. On the other hand, the accompanying drawings of the present invention only illustrate the case where the sealing member G is tightly attached to the outer peripheral surface of the upper region of the housing 220 (see reference). Figure 13 The case where it is formed by adhering to the inner peripheral surface of the upper region of the outer casing 220 (see reference). Figure 14 However, the present invention is not limited to such embodiments. The sealing member G described above can be configured to be closely attached to the inner and outer peripheral surfaces of the upper region of the housing 220. In addition, the sealing member G can also be configured to be sandwiched between the uppermost end of the housing 220 and the lower surface of the welding shield body 110.

[0098] Reference Figure 3 and Figure 4 The welding mask body 110 of the present invention includes a suction section 113. The suction section 113 is configured to communicate with the internal space of the insertion guide 120. When the welding mask body 110 includes such a suction section 113, foreign matter, including welding spatter and / or welding fumes, generated inside the insertion guide 120 during laser welding can be smoothly discharged to the outside.

[0099] The suction section 113 described above can be a hole that penetrates the welding shield body 110. For example, a suction device can be inserted into the suction section 113. When purge gas is injected through the gas injection section 112 as described above, and suction is performed through the suction section 113, foreign matter generated during laser welding is discharged through the suction section 113, and the purge gas can also be circulated. Multiple suction sections 113 are provided. In this case, multiple suction sections 113 are arranged around the laser passage section 111. In this way, when foreign matter generated during laser welding is discharged to the outside through a separate suction section 113 instead of through the laser passage section 111, the device for laser irradiation and the device for suction are provided at different positions on the welding shield body 110, thus preventing interference between the two devices.

[0100] Reference Figure 4 The suction section 113 is directly connected to the laser passage section 111. In this case, foreign matter generated during laser welding passes through the internal space of the insertion guide 120 and the internal space of the laser passage section 111, and is discharged to the outside through the suction section 113.

[0101] Figure 13 This is a diagram used to illustrate an embodiment in which the suction section and the insertion guide of the welding shield provided in this invention are directly connected.

[0102] Reference Figure 13 ,and Figure 4 In a different configuration, the suction section 113 is directly connected to the insertion guide 120. In this case, foreign matter generated by laser welding is discharged from the interior space of the insertion guide 120 through the interior space of the suction section 113 without passing through the laser passage section 111. This prevents problems such as laser focus misalignment caused by interference between foreign matter and the laser, thus ensuring that foreign matter generated by laser welding is discharged without passing through the laser passage section 111.

[0103] Figure 14 This diagram illustrates the circulation path of the purge gas and the path for discharging foreign matter generated during welding when the welding shield of the present invention includes a laser-passing section, a purge gas injection section, and a suction section.

[0104] Reference Figure 14When the welding shield body 110 independently comprises a laser transmission section 111, a gas injection section 112, and a suction section 113, the purge gas flows into the interior of the housing 220 and is discharged through paths ① to ④. That is, the purge gas is injected into the interior of the housing 220 along path ①, flows into the space between the inner wall of the winding center hole and the insertion guide 120 along path ②, flows into the interior of the insertion guide 120 along path ③, and is discharged to the exterior of the welding shield 100 and the battery unit 200 along path ④. On the other hand, foreign matter, including welding spatter and / or welding fumes, generated at the lowermost end of the winding center hole of the electrode assembly 210, is discharged to the exterior of the welding shield 100 and the battery unit 200 along path ④.

[0105] According to the structure of the present invention, the purge gas is supplied to the welding area in a concentrated manner, thereby minimizing the oxygen concentration in the welding area. It also prevents foreign matter generated during laser welding from damaging the electrode assembly 210 and prevents the accumulation of foreign matter in the welding area from causing a decrease in welding quality.

[0106] Below, with reference to this application Figures 3 to 14 The method of welding the workpiece disposed on the battery cell 200 using the welding mask 100 of the present invention described above will be explained.

[0107] One embodiment of the welding method of the present invention relates to a method for welding a workpiece located inside the housing 220 of a battery cell 200. The welding method includes: a welding mask placement step (step A) of placing a welding mask into an opening formed in the housing 220 of the battery cell 200; and a welding step (step B) of welding the workpiece inside the housing 220 through the welding mask 100.

[0108] Step A above is as follows: the welding mask 100, including the welding mask body 110 and the insertion guide 120 extending downward from the welding mask body 110, is lowered to cover the open portion of the housing 220 formed in the battery cell 200, and the insertion guide 120 is inserted into the take-up center hole of the electrode assembly 210 provided inside the housing 220. Step B above is as follows: laser L is irradiated by the laser passage 111 provided in the welding mask body 110 and the insertion guide 120 to weld the workpiece located on the closed portion side of the housing 220 provided on the opposite side of the open portion.

[0109] Therefore, the laser irradiated from the outside of the battery cell 200 passes through the laser passage 111 and the insertion guide 120, passes through the take-up center hole of the electrode assembly 210, and reaches the workpiece to be welded. Furthermore, the insertion guide 120 acts as a shield between the laser and the inner wall surface of the take-up center hole, thus preventing damage to the electrode assembly 210 caused by laser transmission errors, such as when the device for irradiating the laser is installed. In addition, it prevents foreign objects such as welding spatter and welding fumes generated during laser welding from reaching the inner wall surface of the take-up center hole and damaging the electrode assembly 210, and / or preventing short circuits caused by metal foreign objects within the electrode assembly 210.

[0110] In addition to the two steps described above, the welding method also includes a gas injection step (step C). Step C is a step of injecting purge gas into the interior of the casing 220 by welding the shield body 110. This reduces the oxygen concentration inside the casing 220 of the battery cell 200.

[0111] Step C above is as follows: the purge gas injected into the interior of the housing 220 flows into the space between the inner wall of the take-up center hole and the insertion guide 120, and then into the interior of the insertion guide 120. This effectively reduces the oxygen concentration in the welding area of ​​the workpiece irradiated by the laser L.

[0112] Step C above is as follows: purge gas flowing in through the space between the inner wall of the take-up center hole and the insertion guide 120 flows into the interior of the insertion guide 120, for example, through the air inlet 121 formed in the insertion guide 120. Alternatively, step C above can also be as follows: purge gas flowing in through the space between the inner wall of the take-up center hole and the insertion guide 120 flows into the interior of the insertion guide 120 through the gap formed between the lowermost end of the insertion guide 120 and the workpiece to be welded.

[0113] The above welding method also includes a suction step (step D) to remove foreign matter generated during laser welding. That is, the above welding method includes steps A and B, or includes steps A, B and C, or includes steps A, B and D, or includes steps A, B, C and D.

[0114] Step D above can be as follows: when welding the workpiece through the welding shield body 110, foreign matter generated inside the insertion guide 120, including at least one of welding spatter and welding fumes, is sucked out. Thus, foreign matter, including welding spatter and / or welding fumes, generated inside the insertion guide 120 during laser welding, can be smoothly discharged to the outside.

[0115] Step D described above can be a step of suctioning foreign objects through a suction section 113 configured to communicate with the insertion guide 120. For example, step D can be a step of suction performed through a suction section 113 configured to directly communicate with the laser passage section 111. In contrast, step D can be a step of suction performed through a suction section 113 configured to directly communicate with the insertion guide 120. In this way, by suctioning out foreign objects without passing through the laser passage section 111, problems such as laser focus misalignment caused by interference between foreign objects and the laser can be prevented.

[0116] While the present invention has been described above with reference to specific embodiments and accompanying drawings, the present invention is not limited thereto. Of course, those skilled in the art can make various modifications and variations within the equivalent scope of the technical concept of the present invention and the claims described below.

Claims

1. A welding mask, characterized in that, It includes: The welding shield body has a laser-passing part and an opening covering one side of the battery cell's outer casing, allowing laser light irradiating the interior of the battery cell's outer casing to pass through the laser-passing part. The welding shield further includes an insertion guide with a hollow structure, which is connected to the laser passage portion and inserted into the take-up center hole of the electrode assembly housed inside the housing. The aforementioned welding mask body includes a gas injection section capable of injecting purge gas into the interior of the outer casing through the welding mask body. Furthermore, the insertion guide is disposed separately from the inner wall surface of the winding center hole. The aforementioned insertion guide allows purge gas that flows into the space between the inner wall surface of the aforementioned take-up center hole and the aforementioned insertion guide to flow into the interior.

2. The welding mask according to claim 1, characterized in that, The width of the inlet of the laser passage is wider than the width of the outlet.

3. The welding mask according to claim 1, characterized in that, The aforementioned insertion guide is inserted through the inlet of the aforementioned take-up center hole and extends to the outlet of the aforementioned take-up center hole located on the opposite side of the aforementioned inlet.

4. The welding mask according to claim 1, characterized in that, The aforementioned welding shield also includes a gas guide that guides the flow of the purging gas toward the gap between the inner wall surface of the aforementioned take-up center hole and the aforementioned insertion guide.

5. The welding mask according to claim 1, characterized in that, The aforementioned insertion guide has at least one air inlet.

6. The welding mask according to claim 5, characterized in that, The aforementioned air inlet has a groove extending upwards from the lowest end of the aforementioned insertion guide.

7. The welding mask according to claim 5, characterized in that, The aforementioned air inlet is positioned such that it is separated from the bottom of the aforementioned insertion guide by a predetermined distance upwards.

8. The welding mask according to claim 5, characterized in that, The aforementioned welding shield also includes a mesh component configured to cover the aforementioned air inlet.

9. The welding mask according to claim 1, characterized in that, The lowermost end of the aforementioned insertion guide is positioned separately from the workpiece being welded.

10. The welding mask according to claim 1, characterized in that, The aforementioned welding shield also includes a sealing component, which is used to improve the airtightness of the joint between the welding shield body and the outer shell.

11. The welding mask according to claim 1, characterized in that, The aforementioned welding shield body also includes a suction section, which communicates with the internal space of the aforementioned insertion guide.

12. The welding mask according to claim 11, characterized in that, The aforementioned suction section is directly connected to the internal space of the aforementioned laser passage section.

13. A welding method for welding a workpiece located inside the casing of a battery cell, characterized in that, include: The welding mask placement step, namely step A, involves lowering the welding mask, which includes the welding mask body and the insertion guide extending downward from the welding mask body, to cover the opening of the housing formed on the battery cell, and inserting the insertion guide into the take-up center hole of the electrode assembly provided inside the housing. The welding step, or step B, involves irradiating the welded object located on the closed portion side of the outer casing, opposite to the open portion, with a laser through the laser-passing portion and the insertion guide provided in the welding shield body; and The gas injection step, or step C, involves injecting purge gas into the interior of the outer casing through the aforementioned welding shield body. The above-mentioned step C is as follows: the purge gas injected into the interior of the housing flows into the space between the inner wall surface of the winding center hole and the insertion guide, and then flows into the interior of the insertion guide.

14. The welding method according to claim 13, characterized in that, Step C above consists of the following steps: The purging gas that flows in through the space between the inner wall of the winding center hole and the insertion guide flows into the interior of the insertion guide through the air inlet formed in the insertion guide.

15. The welding method according to claim 13, characterized in that, Step C above consists of the following steps: The purge gas flows into the interior of the insertion guide through an air inlet formed at the lower end of the insertion guide.

16. The welding method according to claim 13, characterized in that, Step C above consists of the following steps: The purging gas that flows in through the space between the inner wall surface of the winding center hole and the insertion guide flows into the interior of the insertion guide through the gap between the lowermost end of the insertion guide and the workpiece to be welded.

17. The welding method according to claim 13, characterized in that, The above welding method also includes step D, which involves sucking out at least one of the foreign matter, including welding spatter and welding fumes, generated inside the insertion guide when welding the workpiece through the welding shield body.

18. The welding method according to claim 17, characterized in that, Step D above consists of the following steps: The foreign object is suctioned out through a suction section that is connected to the aforementioned insertion guide.

19. The welding method according to claim 17, characterized in that, Step D above consists of the following steps: Suction is performed through a suction section that is connected to the aforementioned laser passage section.

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