JP7586136B2 - Electrode assembly manufacturing method and electrode assembly manufacturing device - Google Patents

Description

This disclosure relates to an electrode assembly manufacturing method and an electrode assembly manufacturing device.

JP 2000-353514 A (Patent Document 1) discloses a coating line in which a paste material for an electrode active material is applied to one side of an electrode sheet unwound by a winding section using a surface coating device. In the coating line, the paste material is dried in a drying chamber.

JP 2000-353514 A

However, Patent Document 1 does not take into consideration drying the paste material by laser heating in order to dry the applied paste material more efficiently. When drying the paste material by laser, steam evaporated from the paste material may interfere with the laser irradiation, which may reduce the efficiency of drying by laser irradiation. Therefore, it is desirable to suppress the reduction in drying efficiency when drying the paste material (electrode material) by laser.

The present disclosure has been made to solve the above problems, and its purpose is to provide an electrode body manufacturing method and electrode body manufacturing device that can suppress a decrease in drying efficiency when drying an electrode material with a laser.

The electrode body manufacturing method according to a first aspect of the present disclosure includes a conveying step of conveying an electrode body coated with at least one electrode material by a conveying unit, and a drying step of drying the electrode material while conveying the electrode body by the conveying unit. The drying step includes an irradiation step of drying the electrode material by irradiating the electrode material with a laser when the electrode body is conveyed to at least one first position in the conveying direction of the conveying unit, and a recovery step of recovering steam generated due to the laser irradiation of the electrode material by a steam recovery unit provided at at least one second position adjacent to the first position in the conveying direction.

In the electrode body manufacturing method according to the first aspect of the present disclosure, as described above, the vapor generated due to the laser irradiation of the electrode material is collected by a vapor recovery section provided at least one second position adjacent to the first position in the conveying direction. This allows the amount of vapor at the first position to be reduced, since the vapor generated at the first position is collected by the vapor recovery section at the second position. As a result, the laser can be prevented from being blocked by the vapor, and therefore the drying efficiency by the laser can be prevented from decreasing.

In the electrode body manufacturing method according to the first aspect, the recovery step preferably includes recovering the vapor generated from the electrode material by the vapor recovery unit while the electrode material is being irradiated with the laser. With this configuration, the vapor around the electrode material can be recovered during the laser irradiation, so that the vapor can be easily prevented from blocking the laser irradiation of the electrode material.

In the electrode body manufacturing method according to the first aspect, the irradiation step is preferably a step of irradiating the electrode material with a laser at each of a plurality of first positions spaced apart from one another in the conveying direction. The recovery step is a step of recovering steam by a steam recovery section disposed at each of a plurality of second positions located between adjacent first positions in the conveying direction. With this configuration, the steam generated at each of the plurality of first positions can be recovered by the steam recovery section. As a result, a decrease in the drying efficiency by the laser can be suppressed at each of the plurality of first positions.

In the electrode body manufacturing method according to the first aspect, the electrode material preferably includes a first portion near one end in the conveying direction, a second portion near the other end in the conveying direction, and a third portion between the first and second portions, and the irradiation step is a step of making the energy of the laser when at least one of the first and second portions is located within the laser irradiation area and the third portion is located outside the irradiation area smaller than the energy of the laser when the third portion is located within the irradiation area. Here, when a liquid electrode material is applied to a surface, the thickness of the electrode material near the end (near the edge) is smaller than the thickness of the portion other than the near the end. Therefore, by adjusting the energy of the laser as described above, it is possible to prevent the relatively thin near the end from being excessively dried by the laser. Note that the near the end means an area including both the end itself and the portion near the end.

In the electrode body manufacturing method according to the first aspect, the irradiation step is preferably a step of irradiating the electrode material with a laser while aligning the laser irradiation area with the electrode material arrangement area in the width direction of the conveying section perpendicular to the conveying direction. With this configuration, it is possible to prevent the laser from being irradiated to areas other than the electrode material.

In this case, the irradiation step is preferably a step of irradiating the electrode material with a laser in a state in which the energy of the laser corresponding to the vicinity of both ends in the width direction of the irradiation area is smaller than the energy of the laser corresponding to the center part in the width direction of the irradiation area. In this configuration, it is possible to prevent the both ends, which have a relatively small thickness, from being excessively dried by the laser. Note that the vicinity of both ends means the areas including both the ends themselves and the parts near the both ends.

In the electrode body manufacturing method according to the first aspect, the irradiation step is preferably a step of heating the electrode material to 150 degrees or more by a laser. Here, when the electrode material is heated to 150 degrees or more, the fluorine component (adhesive component) in the electrode material tends to migrate from the adhesive surface between the electrode material and the foil portion (the member to which the electrode material is adhered) to the surface side of the electrode material. Therefore, by heating the electrode material to 150 degrees steeply (in a short time) by a laser, the heating time is shortened, and the migration of the fluorine component can be suppressed.

In the electrode body manufacturing method according to the first aspect, the electrode body preferably includes a foil portion and a plurality of electrode materials arranged side by side along a predetermined direction on the surface of the foil portion, the conveying step is a step of conveying the electrode body so that the plurality of electrode materials are conveyed side by side along the conveying direction, and the irradiating step is a step of setting the laser energy to zero when a portion of the foil portion between the electrode materials passes through the laser irradiation area. With this configuration, it is possible to suppress consumption of laser energy by setting the energy of the laser irradiated to the foil portion to zero.

The electrode body manufacturing apparatus according to a second aspect of the present disclosure includes a conveying section that conveys an electrode body coated with at least one electrode material, a laser irradiation section that irradiates the electrode material with a laser to dry the electrode material when the electrode body is conveyed to at least one first position in the conveying direction of the conveying section, and a vapor recovery section that is provided at at least one second position adjacent to the first position in the conveying direction and that recovers vapor generated as a result of the electrode material being irradiated with the laser.

In the electrode body manufacturing apparatus according to the second aspect of the present disclosure, as described above, the vapor generated due to the laser irradiation of the electrode material is collected by a vapor recovery section provided in at least one second position adjacent to the first position in the conveying direction. This allows the amount of vapor at the first position to be reduced, since the vapor generated at the first position is collected by the vapor recovery section at the second position. As a result, it is possible to prevent the laser from being blocked by the vapor, and therefore it is possible to provide an electrode body manufacturing apparatus capable of preventing a decrease in the drying efficiency by the laser.

According to the present disclosure, when drying electrode materials using a laser, it is possible to suppress a decrease in drying efficiency.

FIG. 1 is a diagram showing a configuration of an electrode assembly manufacturing apparatus according to an embodiment. FIG. 2 is a partially enlarged perspective view of FIG. 1 . 3 is a diagram showing a cross-sectional view taken along line III-III in FIG. 2 and the spatial distribution of laser energy. 1A and 1B are diagrams showing a laser irradiation area and a spatial distribution of laser energy. FIG. 2 is a flow diagram showing a method for manufacturing an electrode assembly according to one embodiment. FIG. 1 is a diagram showing the relationship between a laser irradiation area and laser energy in an electrode material. FIG. 4 is a diagram showing a temperature change on the surface of an electrode material due to laser irradiation. FIG. 13 is a diagram showing the distribution of fluorine components in an electrode material after laser irradiation. FIG. 13 is a diagram showing the peel strength of an electrode material after laser irradiation and the peel strength after drying in a drying oven (Comparative Example).

Embodiments of the present disclosure will now be described in detail with reference to the drawings. In the drawings, identical or corresponding parts are designated by the same reference numerals and their description will not be repeated.

In this specification, the X direction and the Y direction are examples of the "conveying direction" and the "width direction" of the present disclosure, respectively. The Z direction is a direction perpendicular to both the X direction and the Y direction. The laser irradiation unit 40 described below irradiates the laser in the Z2 direction.

Figure 1 is a diagram showing the configuration of an electrode body manufacturing apparatus 100 according to this embodiment. In the electrode body manufacturing apparatus 100, an electrode material 1 (positive electrode material or negative electrode material) (see Figure 2) is applied to a metal foil 2 (aluminum foil or copper foil) (see Figure 2) to manufacture an electrode body 10 (see Figure 2). A plurality of electrode materials 1 are arranged in a line on the surface 2a of the metal foil 2 along a predetermined direction (the left-right direction in Figure 2). The electrode body 10 is used, for example, in an on-board lithium-ion battery. The metal foil 2 is an example of the "foil portion" of this disclosure.

(Electrode body manufacturing equipment)
As shown in Fig. 1, the electrode body manufacturing apparatus 100 includes a coating unit 20, a conveying unit 30, a plurality of laser irradiation units 40, and a plurality of steam suction units 50. In the example shown in Fig. 1, the conveying unit 30 conveys the electrode body 10 to the X2 side. The conveying unit 30 conveys the electrode body 10 at a constant speed. The steam suction unit 50 is an example of a "steam recovery unit" in the present disclosure.

The coating unit 20 is configured to be able to eject the liquid electrode material 1. The coating unit 20 coats (applies) the liquid electrode material 1 onto the surface 2a of the metal foil 2.

The conveying section 30 includes a first roll section 31, a second roll section 32, a winding section 33, and a belt section 34. The belt section 34 is tensioned by the first roll section 31 and the second roll section 32. The belt section 34 is also wound up by the winding section 33. As a result, the electrode body 10 (metal foil 2) placed on the belt section 34 is moved toward the winding section 33.

The first roll unit 31 is provided upstream of the conveying unit 30. The second roll unit 32 is provided downstream of the conveying unit 30 from the first roll unit 31. The coating unit 20 applies the electrode material 1 to the metal foil 2 passing through the first roll unit 31.

The multiple laser irradiation units 40 are arranged at intervals from each other along the direction in which the conveying unit 30 (belt unit 34) extends. The multiple laser irradiation units 40 may be arranged at equal intervals from each other.

Each of the multiple laser irradiation units 40 is arranged to be able to irradiate a laser toward the belt unit 34. Each of the multiple laser irradiation units 40 irradiates the electrode material 1 with a laser when the electrode body 10 (electrode material 1) is transported to position P1 in the X direction. Therefore, the electrode material 1 is repeatedly irradiated with a laser. As a result, the liquid electrode material 1 is dried by the heat of the laser. Note that position P1 corresponds to the position of the irradiation region R where the laser of each of the multiple laser irradiation units 40 is irradiated.

Each of the multiple steam suction units 50 is provided at position P2 adjacent to position P1 in the X direction. The most upstream steam suction unit 50 of the multiple steam suction units 50 is provided upstream (X1 side) of the most upstream position P1. The most downstream steam suction unit 50 of the multiple steam suction units 50 is provided downstream (X2 side) of the most downstream position P1. The multiple steam suction units 50 other than the above two steam suction units 50 are each arranged one by one between adjacent positions P1 (laser irradiation units 40).

Each of the multiple steam suction units 50 sucks in steam V (see FIG. 2) that is generated when the electrode material 1 is irradiated with a laser at the adjacent position P1. The steam V is a gas that contains water vapor and other gases. The distance between positions P1 and P2 is such that the steam suction unit 50 can suck in the steam V (the suction force can reach it).

Each of the multiple steam suction units 50 includes a suction port 51 for steam V and a flow pipe 52 for steam V. The flow pipe 52 allows the steam V introduced from the suction port 51 to flow. The width W1 of the suction port 51 in the X direction gradually increases toward the conveying unit 30 side (Z2 side). Specifically, the suction port 51 has a cone shape that widens toward the conveying unit 30 side. In other words, the suction port 51 has a shape that narrows toward the opposite side (Z1 side) from the conveying unit 30. This makes it easier for the steam V generated at the adjacent position P1 to be sucked in through the suction port 51. The suction port 51 and the conveying unit 30 (belt unit 34) are spaced apart by a predetermined distance D in the Z direction.

Also, as shown in FIG. 3, in the Y direction, the laser irradiation area R coincides with the arrangement area of the electrode material 1. In other words, the position in the Y direction of the end R1 on the Y1 side of the laser irradiation area R coincides with the position in the Y direction of the end 1a on the Y1 side of the electrode material 1. Also, the position in the Y direction of the end R2 on the Y2 side of the laser irradiation area R coincides with the position in the Y direction of the end 1b on the Y2 side of the electrode material 1. Therefore, the width W2 in the Y direction of the laser irradiation area R is equal to the width W3 in the Y direction of the electrode material 1.

In addition, in the Y direction, the thickness t of the electrode material 1 in the Z direction is not uniform. Specifically, the thickness t near both ends (1a, 1b) of the electrode material 1 is smaller than the thickness t of the central portion 1c of the electrode material 1 in the Y direction. Specifically, in a cross-sectional view along the Y direction (cross-sectional view of Figure 3), the cross-section of the electrode material 1 has a mountain-like shape with a flat center.

Here, the laser energy corresponding to the vicinity of both ends (R1, R2) in the Y direction of the laser irradiation region R is smaller than the laser energy corresponding to the center R3 in the Y direction of the irradiation region R. Specifically, in a graph showing the relationship between the position in the Y direction and the amount of laser energy as shown in FIG. 3, the waveform of the laser energy is a mountain-shaped waveform with a flat center that corresponds to the cross-sectional shape of the electrode material 1 in the Y direction.

Also, as shown in FIG. 4, the laser energy corresponding to the vicinity of both ends (R4, R5) in the X direction of the laser irradiation region R is smaller than the laser energy corresponding to the center R6 in the X direction of the irradiation region R. Specifically, in the graph showing the relationship between the position in the X direction and the amount of laser energy as shown in FIG. 4, the waveform of the laser energy is a mountain-shaped waveform that corresponds to the cross-sectional shape (not shown) of the electrode material 1 along the X direction. Also, the waveform of the laser energy may be a triangular or square waveform, etc.

The width W4 of the laser irradiation area R in the X direction is smaller than the width W2 of the irradiation area R in the Y direction (see FIG. 3). The irradiation area R is fixed and does not move. The width W5 of the electrode material 1 in the X direction (see FIG. 2) is larger than the width W3 of the electrode material 1 in the Y direction (see FIG. 2).

(Electrode body manufacturing method)
Next, a method for manufacturing the electrode assembly 10 using the electrode assembly manufacturing apparatus 100 will be described with reference to FIGS.

First, in step S10 shown in FIG. 5, the metal foil 2 is placed on the conveying section 30 (belt section 34), and the metal foil 2 is conveyed by the conveying section 30 (conveyance is started).

Next, in step S20, the coating unit 20 (see FIG. 1) applies a plurality of electrode materials 1 to the surface 2a of the metal foil 2 being transported by the transport unit 30. At this time, the plurality of electrode materials 1 are arranged on the surface 2a at intervals from each other. As a result, the plurality of electrode materials 1 are transported side by side along the X direction on the surface 2a of the metal foil 2.

Next, in step S30, the electrode material 1 is dried while the electrode body 10 is transported by the transport unit 30. Specifically, in step S30, a drying process (step S31) is performed in which the electrode material 1 is dried by irradiating a laser onto the electrode material 1 when the electrode body 10 (electrode material 1) is transported to each of the multiple positions P1. In addition, in step S30, a suction process (step S32) is also performed in which the steam V is sucked in by the steam suction units 50 provided at multiple positions P2 adjacent to the position P1 in the X direction. The suction process is an example of the "recovery process" of the present disclosure.

In the suction step (S32), while the electrode material 1 is being irradiated with a laser, the vapor V generated from the electrode material 1 is sucked in by the vapor suction unit 50. That is, the period during which the irradiation step (S31) is performed and the period during which the suction step (S32) is performed overlap with each other. Note that the suction of the vapor V by the vapor suction unit 50 is not performed intermittently but is performed continuously.

As shown in FIG. 6, in the irradiation step (S31), the laser irradiation unit 40 irradiates the laser intermittently. Specifically, when the portion 2b of the metal foil 2 between the electrode materials 1 passes through the laser irradiation region R (see FIG. 2), the laser energy is set to 0. Then, the laser is output (the laser energy is made greater than 0) only when the electrode material 1 passes through the laser irradiation region R.

Here, the electrode material 1 includes a first portion 1e near the end 1d on the X1 side. The electrode material 1 also includes a second portion 1g near the end 1f on the X2 side. The electrode material 1 also includes a third portion 1h between the first portion 1e and the second portion 1g. The third portion 1h is adjacent to each of the first portion 1e and the second portion 1g in the X direction. The width W4 of the first portion 1e in the X direction is equal to the width W5 of the second portion 1g in the X direction. The width W6 of the third portion 1h in the X direction is larger (for example, 10 times or more) than the width W4 and the width W5.

In the irradiation step (S31), the energy of the laser when the first portion 1e or the second portion 1g is located within the laser irradiation region R and the third portion 1h is located outside the irradiation region R is made smaller than the energy of the laser when the third portion 1h is located within the irradiation region R.

Specifically, when the first portion 1e or the second portion 1g is located within the laser irradiation region R and the third portion 1h is located outside the irradiation region R, the laser energy is set to 0. Note that in this case, the laser energy may be set to a value greater than 0.

When the third portion 1h is located within the irradiation region R, the laser energy is made greater than 0. In detail, when a portion 1i of the third portion 1h on the second portion 1g side passes through the irradiation region R, the laser energy is increased from 0 to E. When a portion 1j of the third portion 1h on the first portion 1e side passes through the irradiation region R, the laser energy is reduced from E to 0. When a portion 1k of the third portion 1h between portions 1i and 1j passes through the irradiation region R, the laser energy is fixed at E. In the example shown in FIG. 6, the laser energy is increased (reduced) linearly (linearly), but may be increased (reduced) quadratically.

Note that the width W7 of portion 1i in the X direction is equal to the width W8 of portion 1j in the X direction. Therefore, the time required to increase the laser energy and the time required to decrease the laser energy are equal to each other.

In the irradiation step (S31), as shown in FIG. 7, the electrode material 1 is heated to 150° C. or higher by the laser. Specifically, the surface temperature of the electrode material 1 reaches 150° C. or higher (for example, about 155° C.) within a few seconds of the start of the laser irradiation. The surface temperature of the electrode material 1 rises and falls repeatedly in short cycles (for example, about 0.1 second cycles), gradually rising over the above few seconds. The surface temperature of the electrode material 1 rises and falls repeatedly in short cycles due to the alternating cooling caused by the suction of the steam V by the steam suction unit 50 and heating caused by the laser irradiation.

(Evaluation Results)
FIG. 8 is a diagram showing the distribution of fluorine components on the surface of the electrode material 1 (opposite the bonding surface between the electrode material 1 and the metal foil 2) (left side of FIG. 8) and the distribution of fluorine components on the bonding surface between the electrode material 1 and the metal foil 2 (right side of FIG. 8). In FIG. 8, the hatched area indicates the area where the fluorine components are present. As shown in FIG. 8, it was confirmed that the distribution of the fluorine components does not vary significantly (is uniform) for each part of the electrode material 1. Therefore, it was confirmed that the excessive decrease in the adhesion between the electrode material 1 and the metal foil 2 due to the excessive decrease in the amount of fluorine components on the bonding surface between the electrode material 1 and the metal foil 2 was suppressed. In addition, it was confirmed that the excessive bias of the fluorine components on the surface side of the electrode material 1 was suppressed, and therefore the electrical resistance between the surface and the layer laminated on the surface was suppressed from becoming excessively large.

Figure 9 shows the peel strength of the electrode material 1 for each laser scanning speed (0.2 m/s, 0.3 m/s, and 0.5 m/s) and the peel strength (comparative example) when the electrode material 1 is dried in a drying oven. The scanning speed corresponds to the conveying speed of the conveying section 30 in the above embodiment. It was confirmed that the peel strength at each scanning speed was greater than the peel strength obtained in the drying oven. It was also confirmed that the peel strength was greatest when the laser scanning speed was 0.5 m/s, which was the highest. The peel strength means the adhesive strength of the electrode material 1 to the metal foil 2.

As described above, in this embodiment, the drying process (S30) includes an irradiation process (S31) in which the electrode material 1 is dried by irradiating the electrode body 10 (electrode material 1) with a laser when the electrode body 10 (electrode material 1) is transported to position P1, and a suction process (S32) in which the steam V is sucked in by the steam suction unit 50 provided at position P2. This allows the steam V generated at position P1 to be sucked in toward position P2, thereby preventing the steam V from accumulating at position P1. As a result, it is possible to prevent the steam V from interfering with the laser irradiation of the electrode material 1.

In addition, when a laser is used to dry (heat) the electrode material 1, the temperature of the tool (in this case, the laser irradiation unit 40) itself does not rise, unlike when a heater or the like is used. This eliminates the need to provide a mechanism for cooling the tool (for example, a water-cooling mechanism or an air-cooling mechanism), making it possible to simplify the configuration of the device (equipment) and reduce the number of parts.

In addition, when drying electrode material 1 using an infrared heater, infrared rays having a wavelength that can be measured by a pyrosensor are output from the infrared heater, making it impossible to measure the temperature of electrode material 1. In contrast, when a laser is used, there is no output of infrared rays as described above, making it possible to measure the temperature of electrode material 1. This allows feedback control based on the measured temperature, making it possible to precisely adjust the temperature of electrode material 1.

In addition, in the above embodiment, an example is shown in which the electrode material 1 is irradiated with a laser at multiple positions P1 and the steam suction unit 50 is provided at multiple positions P2, but the present disclosure is not limited to this. The laser may be irradiated at one position P1, and the steam suction unit 50 may be provided at one position P2 adjacent to the one position P1.

The configurations described in the above embodiments and the various modifications described above may be implemented in any combination.

The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present disclosure is indicated by the claims rather than the description of the embodiments above, and is intended to include all modifications within the meaning and scope of the claims.

1 electrode material, 1d, 1f end (end of electrode material), 1e first part, 1g second part, 1h third part, 2 metal foil (foil part), 2a surface (surface of metal foil), 2b part (metal foil part), 10 electrode body, 30 transport part, 40 laser irradiation part, 50 steam suction part (steam recovery part), 100 electrode body manufacturing device, P1 position (first position), P2 position (second position), R irradiation area, R1, R2 end (end of irradiation area), R3 center (center of irradiation area), V steam, X direction (transport direction), Y direction (width direction).

Claims (9)

a conveying step of conveying the electrode body coated with at least one electrode material by a conveying unit;
A drying process of drying the electrode material while transporting the electrode body by the transport unit,
The drying step includes:
an irradiation step of drying the electrode material by irradiating the electrode material with a laser when the electrode body is transported to at least one first position in a transport direction of the transport section;
a recovery process for recovering vapor generated due to the laser being irradiated onto the electrode material by a vapor recovery section provided at at least one second position adjacent to the first position in the transport direction. The electrode body manufacturing method according to claim 1, wherein the recovery process includes recovering the vapor generated from the electrode material by the vapor recovery unit while the electrode material is being irradiated with the laser. the irradiation step is a step of irradiating the electrode material with the laser at each of a plurality of first positions spaced apart from each other in the transport direction;
3. The electrode body manufacturing method according to claim 1, wherein the recovery process is a process of recovering the vapor by the vapor recovery section disposed at each of a plurality of the second positions located between the first positions adjacent to each other in the transport direction. the electrode material includes a first portion near an end portion on one side in the transport direction, a second portion near an end portion on the other side in the transport direction, and a third portion between the first portion and the second portion,
3. The electrode body manufacturing method according to claim 1 or 2, wherein the irradiation process is a process of making the energy of the laser smaller when at least one of the first portion and the second portion is located within an irradiation area of the laser and the third portion is located outside the irradiation area than the energy of the laser when the third portion is located within the irradiation area. The electrode body manufacturing method according to claim 1 or 2, wherein the irradiation process is a process of irradiating the electrode material with the laser while aligning the irradiation area of the laser with the arrangement area of the electrode material in the width direction of the conveying section perpendicular to the conveying direction. The electrode body manufacturing method according to claim 5, wherein the irradiation step is a step of irradiating the electrode material with the laser in a state in which the energy of the laser corresponding to the vicinity of both ends in the width direction of the irradiation area is smaller than the energy of the laser corresponding to the center part in the width direction of the irradiation area. The electrode body manufacturing method according to claim 1 or 2, wherein the irradiation process is a process of heating the electrode material to 150 degrees or more by the laser. the electrode body includes a foil portion and a plurality of the electrode materials arranged side by side along a predetermined direction on a surface of the foil portion;
the conveying step is a step of conveying the electrode body such that the plurality of electrode materials are conveyed side by side along the conveying direction,
3. The electrode body manufacturing method according to claim 1, wherein the irradiation step is a step of setting energy of the laser to zero when a portion of the foil portion between the electrode materials passes through an area irradiated with the laser. A conveying unit that conveys an electrode body coated with at least one electrode material;
a laser irradiation unit that irradiates the electrode material with a laser to dry the electrode material when the electrode body is transported to at least one first position in a transport direction of the transport unit;
a vapor recovery section provided in at least one second position adjacent to the first position in the transport direction, which recovers vapor generated due to the electrode material being irradiated with the laser.

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