JP2022160077A - Method of manufacturing electrode foil - Google Patents

Abstract

To provide a method of manufacturing an electrode foil in which the productivity of the electrode foil with a plating layer formed on one side is improved.SOLUTION: A method of manufacturing an electrode foil comprises: a superimposing step of superimposing a first side 11a of a first metal foil 11A and a first side 11a of a second metal foil 11B to form a workpiece W; a joining step of joining one ends 11c, 11c and the other ends 11d, 11d in a width direction of the first metal foil 11A and the second metal foil 11B in the workpiece W; a forming step of plating the workpiece W having undergone the joining step to form a plating layer 12 on a second side 11b of the first metal foil 11A and on the second side 11b of the second metal foil 11B; and a separation step of separating the first side 11a of the first metal foil 11A from the first side 11a of the second metal foil 11B in the workpiece W having undergone the forming step.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to methods for manufacturing electrode foils.

An electrode foil that constitutes a power storage device is manufactured, for example, by forming a plating layer on one side of a metal foil. A technique called hoop plating, for example, is used to form the plating layer. In hoop plating, a long metal foil base material is fed out from a reel, and a plating layer is continuously formed on the metal foil base material by plating the base material conveyed by the reel at a predetermined speed. be able to.

As a technology related to hoop plating, there is a plating apparatus described in Patent Document 1, for example. This conventional plating apparatus is an apparatus for forming a plating layer on a long conductive substrate. In this plating apparatus, an insoluble anode is placed in a plating tank filled with a plating solution, and a conductive substrate is conveyed by a reel so as to face the insoluble anode in the plating tank.

JP 2017-14540 A

From the viewpoint of cost reduction of power storage devices, there is a demand for improved productivity of electrode foils having a plated layer formed on one side.

The present disclosure has been made to solve the above problems, and an object of the present disclosure is to provide a method for manufacturing an electrode foil that can improve the productivity of electrode foil having a plating layer formed on one side.

A method for manufacturing an electrode foil according to one aspect of the present disclosure is a method for manufacturing an electrode foil in which plating is performed while a long first metal foil and a second long metal foil are conveyed, Each of the first metal foil and the second metal foil has a first side and a second side opposite the first side, and the first side of the first metal foil and the second side of the metal foil A stacking step of stacking the first surface to form a work, and a bonding step of bonding one end portions and the other end portions of the first metal foil and the second metal foil in the width direction of the work, respectively. , a forming step of plating the work that has undergone the joining step and forming a plating layer on the second surface of the first metal foil and the second surface of the second metal foil, respectively; and the work that has undergone the forming step, a separating step of separating the first surface of the first metal foil and the first surface of the second metal foil.

In this electrode foil manufacturing method, the first metal foil and the second metal foil are separated from each other after forming plating layers on the first metal foil and the second metal foil that are superimposed on each other. , two electrode foils each having a plated layer formed on one side thereof can be obtained at the same time. As a result, the productivity of the electrode foil having the plated layer formed on one side can be improved.

In the work that has undergone the forming step, a removing step of removing the joined portion between the one end portions and the joined portion between the other end portions may be provided before the separating step. Thereby, in the separation step, the first surface of the first metal foil and the first surface of the second metal foil can be easily separated.

In the overlapping step, the work may be formed by rolling the first metal foil and the second metal foil. As a result, the adhesion between the first surface of the first metal foil and the first surface of the second metal foil is improved, and in the joining step, one end portion in the width direction of the first metal foil and the second metal foil It is possible to suppress the occurrence of joint failure due to separation between the ends and between the other ends.

In the stacking step, the work may be formed by stacking the first surface of the first metal foil and the first surface of the second metal foil via a long core material. In this case, interposing the core material between the two metal foils further increases the strength of the workpiece, so that the metal foil can be more reliably prevented from being distorted or broken when forming the plated layer.

In the joining step, the one end portions and the other end portions of the first metal foil and the second metal foil in the width direction are connected to each other in a state in which no core material is sandwiched between the one end portions and the other end portions. May be joined. Thereby, in the separation step, the first surface of the first metal foil and the first surface of the second metal foil can be easily separated from the core material. In addition, since the core material is not joined to the metal foil, the core material can be reused.

As the core material, a core material having a thickness greater than that of the first metal foil and the second metal foil may be used. As a result, the strength of the workpiece is further increased, so that it is possible to more reliably suppress the occurrence of distortion and breakage of the metal foil when forming the plating layer.

According to the present disclosure, it is possible to improve the productivity of the electrode foil having the plated layer formed on one side.

4 is a flow chart showing a method of manufacturing an electrode foil according to an embodiment of the present disclosure; FIG. 2 is a schematic diagram showing a manufacturing apparatus that implements the electrode foil manufacturing method shown in FIG. 1 ; FIG. 4 is a cross-sectional view showing the state of the workpieces that have undergone a stacking process; It is a perspective view which shows a joining process. FIG. 10 is a cross-sectional view showing the state of the work that has undergone a joining process; FIG. 10 is a cross-sectional view showing the state of the work that has undergone a forming process; It is a perspective view which shows a removal process. FIG. 10 is a cross-sectional view showing the state of the work that has undergone a separation process; (a) is a schematic diagram showing a main part of a manufacturing apparatus for realizing a method for manufacturing an electrode foil according to a modification, and (b) is a cross-sectional view showing the state of a workpiece that has undergone a joining step in the modification. .

Hereinafter, a preferred embodiment of a method for manufacturing an electrode foil according to one aspect of the present disclosure will be described in detail with reference to the drawings.

FIG. 1 is a flow chart showing a method of manufacturing an electrode foil according to one embodiment of the present disclosure. The electrode foil manufactured by this electrode foil manufacturing method is a member that constitutes a power storage device such as a nickel-hydrogen secondary battery or a lithium-ion secondary battery. A power storage device is a device used as a battery for industrial vehicles such as electric vehicles, hybrid vehicles, or forklifts, for example. The electrode foil is constructed by forming a plating layer 12 on one side of a metal foil 11 (see FIG. 8). Here, the case where the metal foil 11 is aluminum foil and the plating layer 12 is copper plating is illustrated. An electrode foil composed of such a metal foil 11 can be configured as a bipolar electrode by applying a negative electrode active material layer on one side and a positive electrode active material layer on the other side.

As shown in FIG. 1, the method of manufacturing the electrode foil includes a step of superimposing two metal foils 11, 11 (step S01), and joining both ends of the metal foils 11, 11 in the width direction. a joining step (step S02), a forming step (step S03) of forming the plating layers 12 on both surfaces of the joined body of the metal foils 11, 11, and a joined portion between both ends in the width direction of the metal foils 11, 11 and a separation step (step S05) for separating the metal foils 11, 11.

FIG. 2 is a schematic diagram showing a manufacturing apparatus for realizing the electrode foil manufacturing method shown in FIG. The manufacturing apparatus 1 shown in FIG. 2 is a so-called hoop-plating (reel-to-reel) electroplating apparatus that carries out plating while conveying a long metal foil 11 between a feed reel 2 and a take-up reel 3 . be. In the transport path of the metal foil 11 between the supply reel 2 and the take-up reel 3, there are a plurality of transport reels 4 for assisting transport while applying necessary tension to the metal foil 11, and a pair of rolling reels 5,5. , a pair of power supply reels 6A and 6B, a plating bath 7, and a pair of separation reels 8 and 8 are arranged.

The manufacturing apparatus 1 is provided with a pair of supply reels 2A, 2B and a pair of take-up reels 3A, 3B. A long first metal foil 11A is fed out from the feeding reel 2A toward the take-up reel 3A. A long second metal foil 11B is fed from the feeding reel 2B toward the take-up reel 3B. The first metal foil 11A and the second metal foil 11B respectively have a first surface 11a and a second surface 11b (see FIG. 3). The width F1 of the first metal foil 11A and the width F2 of the second metal foil 11B are equal here.

In the pair of rolling reels 5, 5, the stacking process of step S01 is performed. Rolling reels 5, 5 are arranged one above the other. By conveying the first metal foil 11A and the second metal foil 11B between the rolling reels 5, 5, as shown in FIG. The first surfaces 11a of the metal foils 11B are overlapped to form a workpiece W of the two metal foils 11. As shown in FIG.

As shown in FIGS. 2 and 4, a joining device 14 is arranged on the transport path of the workpiece W between the rolling reels 5, 5 and the power supply reel 6A in the preceding stage of the plating tank 7. As shown in FIG. In the bonding apparatus 14, the bonding process of step S02 is performed. In this embodiment, the welding device 14 is a rotary ultrasonic welding device 15, and includes a horn 16 that oscillates ultrasonic waves while pressurizing the workpiece W in the thickness direction, and an anvil 17 that serves as a receiving jig for the horn 16. has a pair with The pairs of the horn 16 and the anvil 17 extend across the width of the workpiece W so as to sandwich the widthwise ends 11c, 11c and the other widthwise ends 11d, 11d of the first metal foil 11A and the second metal foil 11B, respectively. are spaced apart in each direction.

By this ultrasonic welding device 15, in the workpiece W that has passed through the rolling reels 5, 5, as shown in FIGS. , 11c and the other end portions 11d and 11d are continuously joined. Here, since the pairs of the horn 16 and the anvil 17 are spaced apart in the width direction of the workpiece W, the central portions in the width direction of the first metal foil 11A and the second metal foil 11B are not joined. , and only the one ends 11c, 11c and the other ends 11d, 11d are continuously joined. The width F3 of the joint portion 13A between the one end portions 11c and 11c and the width F4 of the joint portion 13B between the other end portions 11d and 11d are not particularly limited. It is preferable that the width is about 1/1000 to 1/100 of the width F2 of the foil 11B.

By setting the width F3 of the joint portion 13A and the width F4 of the joint portion 13B to 1/1000 or more of the width F1 of the first metal foil 11A and the width F2 of the second metal foil 11B, the joint portion 13A and the joint portion 13B can be suppressed, and the separation of the first surface 11a of the first metal foil 11A and the first surface 11a of the second metal foil 11B before the separation step can be suitably suppressed. In addition, by setting the width F3 of the joint portion 13A and the width F4 of the joint portion 13B to 1/100 or less of the width F1 of the first metal foil 11A and the width F2 of the second metal foil 11B, the joint to be removed later can be removed. The area of the portion 13A and the joint portion 13B can be sufficiently suppressed, and most of the first metal foil 11A and the second metal foil 11B can be effectively used.

In the pair of power supply reels 6A and 6B and the plating tank 7, the formation process of step S03 is performed. The power supply reels 6A and 6B are both arranged outside the plating tank 7 (above the liquid surface). The work W that has undergone the joining process is conveyed into the plating tank 7 by one of the power supply reels 6A. The work W is reversed in the conveying direction by the conveying reels 4, 4 arranged on the bottom side of the plating tank 7, and conveyed outside the plating tank 7. As shown in FIG. The work transported out of the plating tank 7 is transported to the take-up reel 3 side by the other power supply reel 6B.

The plating bath 7 is filled with a plating solution 21 . As the plating solution 21, for example, a solution containing copper sulfate or copper pyrophosphate is used. A pair of anodes 22A, 22A and a pair of anodes 22B, 22B are arranged in the plating bath 7. As shown in FIG. The anodes 22A and 22B are made of a metal material that is insoluble in the plating solution 21, such as platinum or platinum-plated titanium. The anodes 22A, 22A extend along the conveying direction of the workpiece W from the power supply reel 6A to one of the conveying reels 4, the second surface 11b of the first metal foil 11A and the second surface 11B of the second metal foil 11B. It faces each of the surfaces 11b. The anodes 22B, 22B extend along the conveying direction of the workpiece W from the other conveying reel 4 to the power supply reel 6B, and extend along the second surface 11b of the first metal foil 11A and the second surface 11b of the second metal foil 11B. It faces each of the surfaces 11b.

A voltage from a power supply (not shown) is applied to the anodes 22A, 22A and the power supply reel 6A. A voltage from the same power supply is applied to the anodes 22B, 22B and the power supply reel 6B. As a result, a potential difference is generated between the work W and the anodes 22A and 22B, respectively, and the work W is electroplated. Since the work W has undergone the overlapping process and the joining process before the forming process, the first surface 11a of the first metal foil 11A and the first surface 11a of the second metal foil 11B are exposed to the plating solution 21. I can't touch it. Therefore, as shown in FIG. 6, on the workpiece W that has undergone the forming process, the plating layers 12 are simultaneously formed on the second surface 11b of the first metal foil 11A and the second surface 11b of the second metal foil 11B. be done.

After the plating layer 12 is formed, the workpiece W is transferred to a cleaning device and a drying device (not shown), and a cleaning process and a drying process are performed. As shown in FIGS. 2 and 7, a cutting device 25 is arranged on the conveying path of the work W between the washing device and the drying device and the separation reels 8,8. In the cutting device 25, the removal process of step S04 is performed. In this embodiment, the cutting device 25 is a rotary cutter and has a disc-shaped pair of slit upper blade 26 and slit lower blade 27 . The pair of the slit upper blade 26 and the slit lower blade 27 are arranged at one end side and the other end side in the width direction of the first metal foil 11A and the second metal foil 11B, respectively. Here, the pair of the slit upper blade 26 and the slit lower blade 27 are arranged corresponding to the inner edge of the joint portion 13A between the one end portions 11c and 11c and the inner edge of the joint portion 13B between the other end portions 11d and 11d. It is The cutting device 25 removes from the work W the joined portion 13A between the one end portions 11c and 11c and the joined portion 13B between the other end portions 11d and 11d.

The pair of separation reels 8, 8 are subjected to the separation step of step S05. Between the separation reels 8, 8 and the take-up reel 3A, and between the separation reels 8, 8 and the take-up reel 3B, the transport paths of the first metal foil 11A and the second metal foil 11B are different from each other. there is Thereby, as shown in FIG. 8, the first surface 11a of the first metal foil 11A and the first surface 11a of the second metal foil 11B are separated. The first metal foil 11A with the plating layer 12 formed on the second surface 11b is taken up by the take-up reel 3A, and the second metal foil 11B with the plating layer 12 formed on the second surface 11b is taken up. It is taken up by the take-up reel 3B. After winding, the metal foil 11 with the plating layer 12 is cut into a desired size to obtain the electrode foil that constitutes the power storage device.

As described above, in this electrode foil manufacturing method, after the plating layers 12 are formed on the first metal foil 11A and the second metal foil 11B that are superimposed on each other, the first metal foil and the second metal foil 11B are formed. By separating the metal foil, two electrode foils each having the plating layer 12 formed on one side thereof can be obtained by a single plating process. As a result, the productivity of the electrode foil having the plated layer formed on one side can be improved. In addition, in this electrode foil manufacturing method, the strength of the workpiece W is increased by overlapping the two metal foils 11, so that the metal foil 11 can be prevented from being distorted or broken when the plating layer 12 is formed. In order to join the widthwise ends 11c and 11c of the first metal foil 11A and the second metal foil 11B and the other ends 11d and 11d in the width direction, the first surface of the first metal foil 11A 11a and the first surface 11a of the second metal foil 11B). By suppressing the occurrence of these defects, it becomes unnecessary to add a process for correcting the defects, and the time required for manufacturing the electrode foil can be further shortened.

In this electrode foil manufacturing method, since the one end portions 11c and 11c and the other end portions 11d and 11d are joined together, the center portion of the first metal foil 11A and the center of the second metal foil 11B used as electrode foils are joined together. Parts are not affected by joining or separation. In addition, in this electrode foil manufacturing method, since the work W does not need to be masked, a masking process is not required, which improves productivity. It is also possible to avoid the occurrence of residual adhesive or the like after removing the masking material. Furthermore, damage to the plated layer 12 due to bonding and separation is suppressed in the central portion of the electrode foil coated with the active material layer and capable of being incorporated into the power storage device. Therefore, in manufacturing the electrode foil having the plating layer 12 on one side, the productivity of the electrode foil having the plating layer formed on one side is improved while suppressing the quality deterioration of the electrode foil caused by the damage of the plating layer 12. is planned.
Further, when the one end portions 11c and 11c and the other end portions 11d and 11d are joined to each other by another member such as a masking material or an adhesive, not only the manufacturing cost increases but also the first There is a possibility that the metal foil 11A and the second metal foil 11B are misaligned. On the other hand, in this embodiment, the one ends 11c, 11c and the other ends 11d, 11d are joined by ultrasonic welding. Therefore, it is possible to suppress an increase in the manufacturing cost due to another member for joining, and to suppress the positional deviation of the first metal foil 11A and the second metal foil 11B at the time of attachment. In addition, since the second surface 11b of the first metal foil 11A and the second surface 11b of the second metal foil 11B are not covered with another member for attachment, the plating surface can be maximized. can be secured.

In this embodiment, a removing step is provided before the separating step to remove the joint portion 13A between the one end portions 11c and 11c and the joint portion 13B between the other end portions 11d and 11d. Thereby, in the separation step, the first surface 11a of the first metal foil 11A and the first surface 11a of the second metal foil 11B can be easily separated. In this embodiment, the separation process is performed using a pair of separation reels 8,8. The method using the separation reels 8, 8 is simpler than other methods such as manual work, and can suppress deformation of the first metal foil 11A and the second metal foil 11B.

In this embodiment, the workpiece W is formed by rolling the first metal foil 11A and the second metal foil 11B in the overlapping process. As a result, the adhesion between the first surface 11a of the first metal foil 11A and the first surface 11a of the second metal foil 11B is improved. It is possible to suppress the occurrence of joint failure due to separation of the widthwise ends 11c, 11c and the separation of the other ends 11d, 11d of the second metal foil 11B. Therefore, it is possible to more reliably prevent the plating from reaching the first surface 11a side where the plating layer 12 is not formed.

In addition, by improving the adhesion between the first surface 11a of the first metal foil 11A and the first surface 11a of the second metal foil 11B, for example, when passing through the power supply reels 6A and 6B, the first Deformation of the metal foil 11A and the second metal foil 11B can be suppressed. In the work W, the first metal foil 11A and the second metal foil 11B are overlapped. Therefore, for example, when the work W is conveyed along the power supply reel 6A, the metal foil 11 (here, the second metal foil 11B) on the power supply reel 6A side and the metal foil (here, the second metal foil 11B) overlapping the metal foil 11 1), there is a slight difference in diameter when passing through the power supply reels 6A and 6B. By improving the adhesion between the first surface 11a of the first metal foil 11A and the first surface 11a of the second metal foil 11B, the first metal foil 11A and the second metal foil 11A pass through the reel. Lifting from the foil 11B can be suppressed, and deformation of the first metal foil 11A and the second metal foil 11B can be preferably suppressed.

The present disclosure is not limited to the above embodiments. For example, in the above-described embodiment, the first surface 11a of the first metal foil 11A and the first surface 11a of the second metal foil 11B are directly superimposed in the superimposing step, but as shown in FIG. Then, the long core material 31 is delivered from the delivery roller 2C, and the first surface 11a of the first metal foil 11A and the first surface 11a of the second metal foil 11B are overlapped via the long core material 31. You can match.

The core material 31 is formed in a foil shape from a conductive material such as metal. The core material 31 may be formed in a foil shape from a non-conductive material such as resin. Here, the same aluminum as the metal foil 11 is used as the forming material of the core material 31 . By using the same material for forming the core material 31 as that for forming the metal foil 11 , it is possible to prevent corrosion from occurring on the contact surface between the core material 31 and the metal foil 11 . The thickness T3 of the core material 31 is preferably larger than the thickness T1 of the first metal foil 11A and the thickness T2 of the second metal foil 11B.

According to such a method, the strength of the workpiece W can be increased by interposing the core material 31 between the two metal foils 11 . Further, when the thickness T3 of the core material 31 is made larger than the thickness T1 of the first metal foil 11A and the thickness T2 of the second metal foil 11B, the strength of the workpiece W can be further increased. Become. As a result, it is possible to more reliably suppress the occurrence of distortion and breakage of the metal foil 11 when forming the plating layer 12 .

When the core material 31 is used, the width F5 of the core material 31 may be slightly smaller than the width F1 of the first metal foil 11A and the width F2 of the second metal foil 11B (see FIG. 5). In this case, as shown in FIG. 9(b), in the joining step, the widthwise ends 11c and 11c of the first metal foil 11A and the second metal foil 11B and the other ends 11d and 11d are The one end portions 11c, 11c and the other end portions 11d, 11d can be joined together without the core material 31 being sandwiched therebetween. The core material 31 is a state in which the first metal foil 11A and the second metal foil 11B are not joined to each other, and the first metal foil 11A and the second metal foil 11A and the second metal foil 11A and the second metal foil 11A and the second metal foil 11A and the second metal foil 11A and the second metal foil 11A and the second metal foil 11A and the second metal foil 11A and the second metal foil 11B are formed into a bag shape by the joint portions 13A and 13B. It is held inside the foil 11B.

According to such a method, the first surface 11a of the first metal foil 11A and the first surface B of the second metal foil 11B can be easily separated from the core material 31 in the separation step. Further, since the core material 31 is not joined to the first metal foil 11A and the second metal foil 11B, the core material 31 can be reused. The core material 31 that has undergone the separation step can be recovered, for example, using a take-up reel different from the take-up reels 3A and 3B.

In the above embodiment, the joint portion 13A between the one end portions 11c and 11c and the joint portion 13B between the other end portions 11d and 11d are formed by ultrasonic welding. It is not limited to sonic welding. For example, other joining methods such as adhesive, thermocompression bonding, and laser welding may be used to form the joining portion 13A between the one end portions 11c and 11c and the joining portion 13B between the other end portions 11d and 11d.

In the overlapping process, the gap between the first surface 11a of the first metal foil 11A and the first surface 11a of the second metal foil 11B is sufficiently suppressed to the extent that it does not affect the bonding process. If so, it is not always necessary to roll the first metal foil 11A and the second metal foil 11B. Alternatively, the overlapping process and the bonding process may be performed simultaneously. In this case, for example, the rolling reels 5, 5 may be omitted, and the overlapping process and the joining process may be performed simultaneously by the horn 16 and the anvil 17. The method of plating treatment in the forming process is not limited to electroplating, and other methods such as electroless plating may be used.

In the joining step, joining portions may be formed at portions other than the one end portions 11c and 11c and the other end portions 11d and 11d. Also, the removing step does not necessarily have to be performed. In this case, the entire width of the first metal foil 11A and the second metal foil 11B can be used as the electrode foils, and waste materials can be reduced in manufacturing the electrode foils.

2... delivery reel, 3... take-up reel, 11A... first metal foil, 11B... second metal foil, 11a... first surface, 11b... second surface, 11c... one end, 11d... other end, 12...plated layer, 13A, 13B...joint portion, 31...core material, W...work.

Claims (6)

A method for manufacturing an electrode foil in which plating is performed while a long first metal foil and a second long metal foil are conveyed,
each of the first metal foil and the second metal foil has a first surface and a second surface opposite to the first surface;
a superposing step of superimposing the first surface of the first metal foil and the first surface of the second metal foil to form a workpiece;
a joining step of joining one end portions and the other end portions of the first metal foil and the second metal foil in the width direction of the workpiece;
a forming step of plating the work that has undergone the joining step to form plating layers on the second surface of the first metal foil and the second surface of the second metal foil;
and a separation step of separating the first surface of the first metal foil from the first surface of the second metal foil in the work that has undergone the forming step. 2. The method for manufacturing an electrode foil according to claim 1, further comprising, before the separation step, removing a joint portion between the one end portions and a joint portion between the other end portions of the work that has undergone the forming step. 3. The method of manufacturing an electrode foil according to claim 1, wherein in said overlapping step, said first metal foil and said second metal foil are rolled to form said workpiece. 2. In the overlapping step, the work is formed by overlapping the first surface of the first metal foil and the first surface of the second metal foil via a long core material. 4. A method for producing an electrode foil according to any one of -3. In the bonding step, the core material is sandwiched between the one end portions and the other end portions in the width direction of the first metal foil and the second metal foil. 5. The method for producing an electrode foil according to claim 4, wherein the two parts are joined without being separated. 6. The method of manufacturing an electrode foil according to claim 4, wherein the core material is thicker than the first metal foil and the second metal foil.

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