Secondary battery electrode notching method and secondary battery electrode notching device

Abstract

The present invention relates to a method for notching a secondary battery coated electrode having a coated portion and an insulating layer on an electrode current collector, the method comprising a notching step of notching the insulating layer on the electrode current collector of the coated electrode using a femtosecond laser. In the notching step, the femtosecond laser is used to perform cutting from the insulating layer toward the electrode current collector.

Description

Electrode notching method for secondary batteries and electrode notching device for secondary batteries

[0001] The present invention relates to a method and an electrode notching device for a secondary battery, and more specifically, to a method and an electrode notching device for a secondary battery capable of precisely and efficiently notching an insulating layer of a coated electrode using a femtosecond laser.

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2024-0107924, filed August 12, 2024, and Korean Patent Application No. 10-2025-0110201, filed August 11, 2025, the entire contents of which are incorporated herein by reference.

[0003] Secondary batteries are a key energy storage device in modern industries. Their importance is growing, particularly in the automotive industry. With the proliferation of electric and hybrid vehicles, demand for secondary batteries is skyrocketing.

[0004] The secondary battery electrode manufacturing process involves multiple steps, of which the tab formation process is a crucial one that directly impacts the battery's performance and safety. The tab connects the electrode to the external circuit, and the accuracy of its length and shape influences the battery's internal resistance, charge / discharge efficiency, and lifespan.

[0005] Figure 1 is a plan view schematically showing the process of notching a coating electrode (10) for manufacturing a general secondary battery electrode.

[0006] In this document, the x-axis may represent the driving direction of the coating electrode, and the y-axis may represent the electric field direction of the coating electrode.

[0007] Referring to Fig. 1, the coated electrode (10) includes an electrode current collector (1), an active material coating portion (3), and an insulating coating portion (2). The laser notching process includes a process of forming an electrode tab (5) by removing a first insulating coating portion (2a) coated on one end of the coating electrode (10) in the electric field direction (Y-axis direction) using a laser notching device (30), and a process of forming the other end of the electrode by removing a second insulating coating portion (2b) coated on the other end of the coating electrode (10) using a laser.

[0008] In this laser notching process, the pulse duration of the pulse-shaped signal of IR wavelength (1030 nm to 1064 nm) is nanoseconds (10 -9 seconds) or picoseconds (10 -12 Insulating coating laser notching is performed using a laser.

[0009] However, these existing laser notching technologies have the following limitations:

[0010] Figures 2 and 3 are cross-sectional views schematically showing an IR laser notching device notching a coating electrode. The insulating layer (4) illustrated in Figures 2 and 3 may be a first insulating coating portion (2a) or a second insulating coating portion (2b).

[0011] First, due to the long pulse width of the IR laser, a heat-affected zone is generated around the processing area, which weakens the mechanical properties, and excessive heat generated in the notched cross-section forms dross or residue, which ultimately deteriorates the electrode quality. Second, as shown in FIGS. 2 and 3, when processing with an IR laser, the laser penetrates the insulating layer (4), concentrating heat on the electrode current collector (1), causing the electrode current collector (1) to vaporize and expand, breaking the insulating layer (4). This weakens the adhesive strength between the insulating layer (4) and the electrode current collector (1), making it easy for peeling to occur. Third, due to the relatively large spot size of the IR laser, there is a significant limitation in performing precise processing of fine areas.

[0012] These problems degrade the performance and lifespan of electrodes and affect the overall quality of secondary batteries. Furthermore, increased defect rates lead to lower productivity and higher costs.

[0013] Therefore, there is an urgent need to develop a new laser notching technology that enables precise processing while minimizing thermal effects.

[0014] The present invention aims to solve problems occurring in conventional electrode notching processes.

[0015] Specifically, through one embodiment of the present invention, the purpose is to provide a secondary battery electrode notching device and notching method that can secure high cross-sectional quality while minimizing heat influence by notching an insulating layer of a coated electrode using a femtosecond laser.

[0016] In addition, the present invention aims to provide a secondary battery electrode notching device and notching method capable of precise processing by notching with a smaller focus size using a femtosecond laser of a green wavelength or a UV wavelength through one embodiment of the present invention.

[0017] In addition, the present invention aims to provide a secondary battery electrode notching device and notching method that can effectively focus laser energy on a transparent or translucent insulating layer to achieve high-precision cutting by utilizing the multi-photon absorption phenomenon through one embodiment of the present invention.

[0018] In order to achieve the above-described purpose, according to one embodiment of the present invention, a method for notching a coated electrode for a secondary battery having a coating portion and an insulating layer on an electrode current collector is provided, the method including a notching step of notching an insulating layer on the electrode current collector of the coated electrode using a femtosecond laser, and characterized in that, in the notching step, cutting is performed in a direction toward the electrode current collector from the insulating layer using the femtosecond laser.

[0019] The pulse width of the femtosecond laser may be 100 fs to 5 ps.

[0020] Additionally, the wavelength of the femtosecond laser may be a green wavelength or a UV wavelength.

[0021] Additionally, the Green wavelength may have a range of 515 nm to 532 nm.

[0022] Additionally, the UV wavelength may range from 343 nm to 355 nm.

[0023] In the above notching step, the average output energy of the femtosecond laser can be in the range of 10 W to 200 W.

[0024] In the above notching step, when the femtosecond laser is irradiated onto the insulating layer, the insulating layer can be cut by directly absorbing the laser wavelength through a multi-photon absorption phenomenon.

[0025] In the above notching step, the insulating layer can be cut before the electrode collector is vaporized by the femtosecond laser.

[0026] The above-described coated electrode may have a first insulating layer and a second insulating layer formed on each of both sides of the electrode current collector, and in this case, in the notching step, the first insulating layer, the electrode current collector, and the second insulating layer may be sequentially notched using the femtosecond laser.

[0027] Additionally, in the above notching step, it may be provided to shape the electrode tab on the continuously transported coating electrode.

[0028] In addition, according to another embodiment of the present invention, a device for manufacturing an electrode for a secondary battery having a coating portion and an insulating layer on an electrode current collector is provided, the device including a notching portion for notching the insulating layer of the coated electrode using a femtosecond laser, and the notching portion is characterized in that it is arranged to perform cutting in a direction from the insulating layer toward the electrode current collector using the femtosecond laser.

[0029] The above-mentioned coated electrode has a first insulating layer and a second insulating layer formed on each side of the electrode current collector, and the notching portion may be provided to sequentially notch the first insulating layer, the electrode current collector, and the second insulating layer using the femtosecond laser.

[0030] Additionally, the pulse width of the femtosecond laser may be 100 fs to 5 ps.

[0031] Additionally, the wavelength of the femtosecond laser may be a green wavelength or a UV wavelength.

[0032] Additionally, the Green wavelength may have a range of 515 nm to 532 nm.

[0033] Additionally, the UV wavelength may range from 343 nm to 355 nm.

[0034] Additionally, the notching part may be arranged to adjust the average output energy of the femtosecond laser in the range of 10 W to 200 W.

[0035] The above notching part can be provided to shape an electrode tab on a continuously transported coating electrode.

[0036] The above notching part may be provided so that when the femtosecond laser is irradiated onto the insulating layer, the insulating layer directly absorbs the laser wavelength through a multi-photon absorption phenomenon and is cut.

[0037] The above notching portion may be provided so that the insulating layer is cut before the electrode collector is vaporized by the femtosecond laser.

[0038] The electrode notching device and notching method for a secondary battery according to one embodiment of the present invention improves problems in the prior art by notching the insulating layer of a coated electrode using a femtosecond laser, thereby enabling precise and efficient shape processing.

[0039] In particular, the short pulse width (100 fs to 5 ps) of the femtosecond laser allows for high energy to be instantly concentrated on the insulating coating without thermal effects, thereby ensuring high cross-sectional quality.

[0040] In addition, the present invention can notch with a smaller focus size by using a femtosecond laser of green wavelength or UV wavelength, and can obtain a focus size more than twice smaller than that of a conventional IR wavelength laser, thereby enabling more precise processing.

[0041] In addition, the notching method related to one embodiment of the present invention utilizes the multi-photon absorption phenomenon to cause the insulating layer to directly absorb the laser wavelength, thereby effectively concentrating the laser energy even on a transparent or translucent insulating layer, thereby enabling high-precision cutting.

[0042] Figure 1 is a schematic plan view showing the process of notching a coated electrode to manufacture a general secondary battery electrode.

[0043] Figures 2 and 3 are cross-sectional views schematically showing an IR laser notching device notching a coating electrode.

[0044] Figure 4 is a partial schematic diagram schematically showing the connection structure of an electrode assembly including an electrode for a secondary battery of the present invention and an electrode lead portion.

[0045] Figure 5 is a schematic diagram showing the configurations of a notching device for a secondary battery electrode according to one embodiment of the present invention.

[0046] Figure 6 is a schematic diagram schematically showing a process of notching a coated electrode using a notching device for a secondary battery electrode according to one embodiment of the present invention.

[0047] FIG. 7 is a partial plan view schematically showing the appearance of a coating electrode showing a notching area of ​​a coating electrode for a secondary battery according to one embodiment of the present invention.

[0048] FIGS. 8 and 9 are cross-sectional views schematically showing a process of notching a coated electrode using a notching device for a secondary battery electrode according to one embodiment of the present invention.

[0049] Figure 10 shows a flow chart of a method for notching an electrode for a secondary battery according to one embodiment of the present invention.

[0050] Figure 11 is a plan view schematically showing a secondary battery according to one embodiment of the present invention.

[0051] Fig. 12 is a cross-sectional photograph of a coating electrode according to a notching method according to one embodiment of the present invention and a cross-sectional photograph of a coating electrode according to a comparative example.

[0052] Hereinafter, a secondary battery electrode notching device (100), a secondary battery electrode notching method (200), and a secondary battery (300) according to one embodiment of the present invention will be described in detail with reference to the attached drawings.

[0053] In addition, regardless of the drawing symbol, identical or corresponding components are given identical or similar reference numbers and redundant descriptions thereof are omitted, and for the convenience of explanation, the size and shape of each component depicted may be exaggerated or reduced.

[0054] Fig. 4 is a partial schematic diagram schematically showing the connection structure of an electrode assembly (320) including an electrode (323) for a secondary battery of the present invention and an electrode lead portion (331). Fig. 5 is a schematic diagram showing the configurations of a notching device (100) for a secondary battery electrode (323) according to an embodiment of the present invention. Fig. 6 is a schematic diagram schematically showing a state of notching a coated electrode using a notching device (100) for a secondary battery electrode (323) according to an embodiment of the present invention. And, Fig. 7 is a partial plan view schematically showing a state of a coated electrode indicating a notching area of ​​a coated electrode for a secondary battery according to an embodiment of the present invention.

[0055] Referring to FIGS. 5 and 6, a notching device (100) for a secondary battery electrode according to one embodiment of the present invention notches a coated electrode (20) running on a roll-to-roll device.

[0056] Referring to FIGS. 1 and 7, the coated electrode (10) includes a coating portion (3) in which an electrode active material (positive electrode active material or negative electrode active material) is coated on the surface of an electrode current collector (1), and an insulating layer (2: 2a, 2b) in which an insulating liquid is coated on the edge of the coating portion (3). The insulating layer (2) may be provided on each of both sides of the coating portion (3) along the electric field direction (Y-axis direction) of the coated electrode (10). In this document, the coated electrode (10) may include a holding portion in which the coating portion (3) and the insulating layer (2) are formed on the electrode current collector (1), and a non-conductive portion which is an area other than the holding portion.

[0057] Referring to FIG. 4, the electrode (323) for a secondary battery is a part of an electrode assembly (320). Specifically, the electrode assembly (320) may include a positive electrode (321) and a negative electrode (322) as electrodes (323), and may include a separator (326) interposed between the positive electrode (321) and the negative electrode (322). The secondary battery (300) may be provided with a positive electrode tab (351) and a negative electrode tab (not shown) provided on each of the positive electrode (321) and the negative electrode (322). In addition, each of the positive electrode tab (351) and the negative electrode tab may be connected to a positive electrode lead (331) and a negative electrode lead (not shown) by welding or the like. For example, a bundle (327) of positive electrode tabs (351) may be welded to the positive electrode lead (331).

[0058] In addition, the coated electrode formed by the electrode notching device (100) can ultimately be used as a part of the positive or negative electrode (323) of the electrode assembly (320).

[0059] Referring to FIGS. 5 and 6, the electrode notching device (100) for a secondary battery of the present invention includes a notching unit (110). For example, the notching unit (110) may be equipped with a laser source, an optical box, a scanner, an F-theta lens, a pattern jig, etc. for laser notching.

[0060] Referring to Fig. 6, while the coating electrode (20) is traveling through the traveling rollers (21), the notching part (110) of the notching device (100) can irradiate the laser (L) to notch the coating electrode (20). At this time, the notching part (110) may be positioned on the upper portion of the coating electrode (20), and a support (30) may be provided on the lower portion of the coating electrode (20) to support the coating electrode (20) upward during notching.

[0061] Referring to Fig. 7, the notching portion (110) is provided to notch the insulating layer (2a, 2b) of the coating electrode (10) using a femtosecond laser. At this time, the notching portion (110) may be provided to perform cutting in a direction from the insulating layer (2) toward the electrode current collector (1) using the femtosecond laser.

[0062] Referring to FIGS. 5 and 7, the notching portion (110) can notch the insulating layer (2a) along the first notching line (S1) of the coating electrode (10). In addition, the notching portion (110) can notch the insulating layer (2b) along the second notching line (S2) of the coating electrode (10) to form and process the other end of the coating electrode (10) in the electric field direction (Y-axis direction) with high cross-sectional quality.

[0063] FIG. 8 and FIG. 9 are cross-sectional views schematically showing a process of notching a coating electrode (20) using a notching device for a secondary battery electrode according to one embodiment of the present invention.

[0064] Referring to FIG. 8, the notching portion (110) may be provided to sequentially notch the first insulating layer (11) formed on the upper surface of the electrode current collector (12) of the coating electrode (20), the electrode current collector (12), and the second insulating layer (13) formed on the lower surface of the electrode current collector (12) using a femtosecond laser (L).

[0065] The above-mentioned notching part (110) can be arranged to perform cutting in the direction from the first insulating layer (11), which is the uppermost layer, toward the electrode current collector (12) using a femtosecond laser (L). Unlike a conventional IR wavelength laser, this can secure cross-sectional quality like plasma cutting by instantly concentrating high energy on the material without thermal influence due to the very high output for a short time of the femtosecond laser (L).

[0066] Referring to FIGS. 6, 8, and 9, the pulse width of the femtosecond laser (L) used in the present invention may be 100 fs to 5 ps. Such ultra-short pulses provide high peak power while minimizing the thermal influence of the insulating coating portion (2), thereby enabling precise processing. For example, when a laser with a pulse width of 1 ps is used, the laser ablation efficiency can be increased because high energy is transferred in a very short period of time, so that the surface of the material is rapidly heated and removed by evaporation or transformation into plasma.

[0067] In general, peak power increases as the pulse width decreases. High peak power is required for direct notching of the insulating layer. For example, for direct notching of an insulating layer containing a mixed composition of boehmite, SBR, and PVDF, experimental results show that direct notching of the insulating layer is possible at 5 ps based on an average output energy of 10 W, and the notching efficiency increases as the pulse width approaches femtoseconds. That is, when the pulse width exceeds 5 ps, the absorption of the laser in the insulating layer decreases and most of the laser passes through the insulating layer, resulting in thermal diffusion in the aluminum current collector.

[0068] The wavelength of the femtosecond laser (L) may be a green wavelength or a UV wavelength. The femtosecond laser (L) may preferably have a green wavelength in the range of 515 nm to 532 nm, and a UV wavelength in the range of 343 nm to 355 nm. Such short-wavelength lasers provide a smaller focus size, enabling more precise processing.

[0069] Meanwhile, at wavelengths below 343 nm, the complexity and cost of laser systems increase dramatically. Conversely, at wavelengths exceeding 532 nm, the light absorption in the insulating coating decreases, reducing processing efficiency. Furthermore, the focal spot size increases, reducing cutting precision. Furthermore, beyond the 343 nm to 532 nm wavelength range, the efficiency of multiphoton absorption decreases, making direct processing of transparent or translucent insulating coatings difficult.

[0070] The above-described notching portion (110) may be provided to adjust the average output energy of the femtosecond laser (L) to a range of 10 W to 200 W in order to secure a laser intensity greater than a predetermined level. Preferably, the average output energy may be adjusted to a range of 50 W to 80 W based on a cutting speed of 1.5 m / s. Alternatively, the average output energy may be adjusted to a range of 100 W to 130 W based on a cutting speed of 3 m / s.

[0071] At outputs below 10 W, it is difficult to secure sufficient energy density to effectively remove the insulating coating (2), which significantly reduces the processing speed and may result in incomplete notching. Furthermore, at outputs exceeding 200 W, the heat-affected zone expands due to excessive heat generation, increasing the risk of damage to the electrode current collector (12).

[0072] Through this configuration, the electrode notching device (100) for a secondary battery of the present invention enables precise and efficient shape processing.

[0073] Referring to FIGS. 5 and 7, the notching device (100) of the present invention operates at a laser intensity higher than a certain threshold value when a femtosecond laser is irradiated onto an insulating layer (2) on an electrode current collector (1), and when the femtosecond laser is irradiated, a multi-photon absorption phenomenon occurs in the insulating layer (2), so that the insulating layer (2) directly absorbs the laser wavelength. Here, the multi-photon absorption phenomenon is one of the nonlinear optical effects, and refers to a process in which a material absorbs two or more photons simultaneously. That is, unlike general light absorption, multi-photon absorption occurs at a very high light intensity, and is mainly observed when using an ultra-short pulse laser such as a femtosecond laser.

[0074] Accordingly, the present invention enables high-precision cutting by effectively focusing laser energy on an insulating layer (2) on an electrode current collector (1) using a femtosecond laser (L). At this time, the insulating layer (2) may include a ceramic material and a binder. The insulating layer (2) may be a transparent or translucent material.

[0075] Additionally, the notching portion (110) can be designed so that the insulating layer (2) is cut before the electrode current collector (1) is vaporized by the femtosecond laser. This allows the insulating layer (2) to be effectively removed while minimizing damage to the electrode current collector (1).

[0076] Referring to FIGS. 8 and 9, in one embodiment of the present invention, a coating electrode (20) may have a first insulating layer (11) and a second insulating layer (13) formed on both sides of an electrode current collector (12), respectively. At this time, the notch (110) may be provided to irradiate a laser from above the first insulating layer (11). When the femtosecond laser (L) is irradiated to the first insulating layer (11), which is the uppermost layer on the electrode current collector (1), a multi-photon absorption phenomenon occurs in the first insulating layer (11), so that the insulating layer (2) directly absorbs the laser wavelength.

[0077] The present invention effectively focuses laser energy on a first insulating layer (11) using a femtosecond laser (L), thereby enabling high-precision cutting. At this time, the first insulating layer (11) may include a ceramic material and a binder. The first insulating layer (11) may be a transparent or translucent material. The second insulating layer (13) may have the same composition as the first insulating layer (11).

[0078] In one embodiment of the present invention, the coated electrode (20) may be formed by coating an insulating layer on both sides of the electrode current collector (12) to form a first insulating layer (11) and a second insulating layer (13). In this case, the notching portion (110) may be provided to sequentially notch the first insulating layer (11), the electrode current collector (12), and the second insulating layer (13) using a femtosecond laser (L). This structure provides uniform insulating properties on both sides of the coated electrode (20), and enables precise processing of each layer through sequential notching.

[0079] Next, a method for notching an electrode for a secondary battery according to one embodiment of the present invention will be described.

[0080] The method for manufacturing a secondary battery electrode (200) of the present invention relates to a method for notching a coated electrode for a secondary battery having a coating portion and an insulating layer on an electrode current collector.

[0081] Figure 10 shows a flow chart of a method (200) for notching an electrode for a secondary battery according to one embodiment of the present invention.

[0082] Referring to FIGS. 5, 7, and 10, the method (200) for manufacturing an electrode for a secondary battery of the present invention includes a notching step (M01). In the notching step (M01), an insulating layer (2) is notched on the electrode collector (1) of the coated electrode (10) using a femtosecond laser.

[0083] As described above, in the notching step (M01), cutting can be performed in the direction from the insulating layer (2) toward the electrode current collector (1) using a femtosecond laser.

[0084] At this time, the pulse width of the femtosecond laser used in the notching method (200) of the present invention may be 100 fs to 5 ps. At this time, the wavelength of the femtosecond laser may be a green wavelength or a UV wavelength.

[0085] Preferably, the femtosecond laser may have a green wavelength in the range of 515 nm to 532 nm, and a UV wavelength in the range of 343 nm to 355 nm.

[0086] In the above notching step (M01), the average output energy of the femtosecond laser (L) may be in the range of 10 W to 200 W. For example, the average traveling speed of the femtosecond laser (L) on the coating electrode (20) may be in the range of 100 mm / s to 2,000 mm / s.

[0087] In addition, in the above-described notching step (M01), when a femtosecond laser is irradiated onto the insulating layer (2), it operates at a laser intensity higher than a certain threshold value, and when such a femtosecond laser is irradiated, a multi-photon absorption phenomenon occurs in the insulating layer (2), so that the insulating layer (2) directly absorbs the laser wavelength. This effectively focuses the laser energy onto a transparent or translucent insulating layer (2), enabling high-precision cutting.

[0088] Accordingly, the present invention can effectively notch the insulating layer of a coated electrode using a femtosecond laser by this configuration. In particular, precise processing is possible even for transparent or translucent insulating layers through the multiphoton absorption phenomenon, and high-quality notching can be performed while minimizing damage to the electrode current collector.

[0089] Additionally, the insulating layer (2) can be cut before the electrode current collector (1) is vaporized by the femtosecond laser (L) in the notching step (M01).

[0090] Referring to FIGS. 8 and 9, in the case of a coated electrode (20) in which a first insulating layer (11) and a second insulating layer (13) are formed on each of both sides of an electrode current collector (12), the first insulating layer (11), the electrode current collector (12), and the second insulating layer (13) can be sequentially notched using a femtosecond laser (L) in the notching step (M01).

[0091] As the femtosecond laser (L) is irradiated on the upper part of the coating electrode (20), a process of sequentially cutting from the first insulating layer (11), which is the uppermost layer, to the electrode current collector (12), and the second insulating layer (13) can be observed.

[0092] Meanwhile, a secondary battery according to one embodiment of the present invention will be described.

[0093] Figure 11 is a plan view schematically showing a secondary battery (300) according to one embodiment of the present invention.

[0094] Referring to FIGS. 4 and 11, the secondary battery (300) of the present invention includes an electrode assembly (320) and a pouch (360). Specifically, the electrode assembly (320) includes an electrode manufactured using the electrode manufacturing method of the present invention. This electrode is precisely shaped and processed through a notching process using a femtosecond laser, thereby providing excellent electrical characteristics and stability.

[0095] The pouch (360) is provided to accommodate the electrode assembly (320). The pouch (360) protects the electrode assembly (320) from the external environment and serves to stably maintain the electrolyte.

[0096] The secondary battery (300) includes a lead portion (330). In addition, the lead portion (330) includes a positive electrode lead (331) and a negative electrode lead (333). The positive electrode lead (331) protrudes outward from the top of the pouch (360), and the negative electrode lead (333) protrudes outward from the bottom. The lead portion (330) can electrically connect the electrode assembly (320) and an external circuit.

[0097] Additionally, a protective film (340) is provided between the pouch (360) and the lead portion (330). This ensures electrical insulation between the lead portion (330) and the pouch (360). A receiving portion (362) for receiving the electrode assembly (320) is formed in the pouch (360).

[0098]

[0099] <Example>

[0100] Fig. 12 is a cross-sectional photograph of a coating electrode according to a notching method according to one embodiment of the present invention and a cross-sectional photograph of a coating electrode according to a comparative example.

[0101] A coated electrode was prepared in which a positive electrode active material was coated on both sides of an aluminum foil electrode current collector having a thickness of 15 μm, and a first insulating layer (15 μm) and a second insulating layer (15 μm) were coated on the edges of the coated portion of the positive electrode active material. The first and second insulating layers have a composition of a mixture of boehmite, styrene-butadiene-rubber (SBR), and polyvinylidene fluoride (PVDF).

[0102] The coating electrode was notched by performing a notching process on the first insulating layer of the coating electrode using a laser device with a wavelength of 515 nm (Green) and an output of 100 W with a femtosecond pulse width (800 fs). At this time, the spot size was less than 15 μm.

[0103] <Comparative Example>

[0104] A coated electrode identical to that in the example was prepared. However, unlike the example, the notching process was performed using a laser device set to a wavelength of 1064 nm (IR) with a picosecond pulse width (more than 10 ps) to notch the coated electrode. At this time, the spot size was less than 30 μm. Other conditions were the same.

[0105] Example Comparison Wavelength 515 nm (Green) 1064 nm (IR) Output 100 W 100 W Spot size Less than 15 μm Less than 30 μm Pulse width 800 fs 10 ps or more

[0106] Referring to Table 1 above and (b) of Fig. 12, in the comparative example, when the coating electrode was notched with an IR wavelength laser having a picosecond pulse width, laser absorption was not sufficiently performed in the first insulating layer, so that excessive heat was concentrated on the electrode current collector, causing vaporization of the electrode current collector, and before the first insulating layer was cut, as in Figs. 2 and 3, a phenomenon occurred in which the first insulating layer swelled and peeled off due to vaporization of the electrode current collector (see A of (b) of Fig. 12).

[0107] Unlike the comparative example, in the femtosecond laser-notched example of the present invention, the first insulating layer was cut before vaporization of the electrode current collector occurred due to direct absorption of the insulating layer by multi-photon absorption in the first insulating layer, and then the electrode current collector and the second insulating layer were sequentially cut. Accordingly, it was confirmed that the cutting profile of the coated electrode in which the first insulating layer, the electrode current collector, and the second insulating layer were sequentially laminated in the example was excellent, and that no peeling phenomenon of the first and second insulating layers occurred (see Fig. 12 (a)).

[0108] The various embodiments of the present invention described above are provided for illustrative purposes and should not be construed as limiting the scope of the present invention. Therefore, the scope of the present invention should be determined not by the described embodiments but by the claims.

[0109] According to an electrode notching device and method for a secondary battery according to one embodiment of the present invention, precise and efficient shape processing is possible by notching the insulating layer of a coated electrode using a femtosecond laser.

Claims

1. A method for notching a coated electrode for a secondary battery having a coating portion and an insulating layer on an electrode current collector, A notching step of notching an insulating layer on an electrode collector of a coated electrode using a femtosecond laser; A method for notching an electrode for a secondary battery, characterized in that, in the notching step, cutting is performed in a direction toward the electrode current collector from the insulating layer using the femtosecond laser.

2. In paragraph 1, A method for notching an electrode for a secondary battery, characterized in that the pulse width of the femtosecond laser is 100 fs to 5 ps.

3. In paragraph 1, The wavelength of the above femtosecond laser is green wavelength, A method for notching an electrode for a secondary battery, characterized in that the green wavelength has a range of 515 nm to 532 nm.

4. In paragraph 1, The wavelength of the above femtosecond laser is a UV wavelength, A method for notching an electrode for a secondary battery, characterized in that the UV wavelength has a range of 343 nm to 355 nm.

5. In paragraph 1, A method for notching an electrode for a secondary battery, characterized in that in the above notching step, the average output energy of the femtosecond laser is in the range of 10 W to 200 W.

6. In the first paragraph, in the notching step, A method for notching an electrode for a secondary battery, characterized in that when the femtosecond laser is irradiated, the insulating layer is cut by directly absorbing the laser wavelength through a multi-photon absorption phenomenon.

7. In paragraph 1, The above-mentioned coated electrode has a first insulating layer and a second insulating layer formed on each of both sides of the electrode current collector, A method for notching an electrode for a secondary battery, characterized in that, in the above notching step, the first insulating layer, the electrode current collector, and the second insulating layer are sequentially notched using the femtosecond laser.

8. In a device for manufacturing an electrode for a secondary battery having a coating portion and an insulating layer on an electrode collector, A notching section for notching an insulating layer of a coating electrode using a femtosecond laser; An electrode notching device for a secondary battery, characterized in that the notching part is configured to perform cutting in a direction from the insulating layer toward the electrode current collector using the femtosecond laser.

9. In paragraph 8, The above-mentioned coated electrode has a first insulating layer and a second insulating layer formed on each side of the electrode current collector, An electrode notching device for a secondary battery, characterized in that the notching part is provided to sequentially notch a first insulating layer, an electrode current collector, and a second insulating layer using the femtosecond laser.

10. In paragraph 8, A secondary battery electrode notching device characterized in that the pulse width of the femtosecond laser is 100 fs to 5 ps.

11. In paragraph 8, The wavelength of the above femtosecond laser is green wavelength, An electrode notching device for a secondary battery, characterized in that the above green wavelength has a range of 515 nm to 532 nm.

12. In paragraph 8, The wavelength of the above femtosecond laser is a UV wavelength, A secondary battery electrode notching device characterized in that the UV wavelength has a range of 343 nm to 355 nm.

13. In paragraph 8, The above notching part is, An electrode notching device for a secondary battery, characterized in that the average output energy of the femtosecond laser is adjusted to a range of 10 W to 200 W.

14. In paragraph 8, The above notching part is, An electrode notching device for a secondary battery, characterized in that it is provided to shape an electrode tab on a continuously transported coating electrode.

15. In paragraph 8, The above notching part is, A secondary battery electrode notching device characterized in that when the femtosecond laser is irradiated, the insulating layer is cut by directly absorbing the laser wavelength through a multi-photon absorption phenomenon.

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