JP2018081858A - Device and method for removing active material mixture layer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To remove a part of an active material mixture layer from an electrode material without imparting moisture.SOLUTION: A device 50 for removing an active material mixture layer includes: a supply nozzle 61 for supplying liquefied gas whose temperature is equal to or less than the glass transition temperature of a binder contained in an active material mixture layer 32; and a scraper 51. When the active material mixture layer 32 is removed, the active material mixture layer 32 is made brittle by liquefied gas to remove the active material mixture layer 32 by the scraper 51.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an active material mixture layer removing apparatus and an active material mixture layer removing method.

  A power storage device such as a lithium ion secondary battery includes positive and negative electrodes. The electrode is manufactured by forming an electrode material having an active material mixture layer on both sides of a long strip-shaped metal foil and cutting the electrode material in accordance with the shape of the electrode.

  The electrode material is manufactured by applying an active material mixture to the belt-shaped metal foil being conveyed. The active material mixture is a paste in which an active material, a conductive agent, a solvent, and a binder are mixed. After manufacturing the electrode material, the defective portion is inspected. The defective portion is, for example, a portion where the thickness of the active material mixture layer that is the active material mixture applied to the belt-shaped metal foil is insufficient. When a defective portion is detected, the defective portion is removed from the electrode material. For this reason, although electrode material is parted, the other part is not a defective part but a part which can manufacture an electrode. Therefore, after removing the defective part, the divided electrode materials are joined to each other for use in manufacturing the electrode.

  When joining the divided electrode materials, the strip-shaped metal foils are generally joined together. In this case, it is necessary to remove the active material mixture layer from the electrode material to obtain an exposed portion where the strip-shaped metal foil is exposed. A method for removing the active material mixture layer is described in Patent Document 1, for example. Patent Document 1 describes that the active material mixture layer applied to the band-shaped metal foil by ultrasonic treatment is partially removed.

JP-A-1-251555

  By the way, when the active material mixture layer is removed by ultrasonic waves, it is necessary to impart moisture to the active material mixture layer in order to propagate ultrasonic waves to the active material mixture layer using moisture as a medium. Moisture causes a SEI film to form on the surface of the active material mixture layer, and the performance of the resulting electrode deteriorates.

  An object of the present invention is to provide an active material mixture layer removal apparatus and an active material mixture layer removal method capable of removing a part of an active material mixture layer from an electrode material without applying moisture. There is to do.

  An apparatus for removing an active material mixture layer that solves the above-described problem is an active material from an electrode material in which an active material mixture layer formed by applying an active material mixture containing a binder is provided on at least one surface of a strip-shaped metal foil. An active material mixture layer removing apparatus for removing a part of a mixture layer, comprising: a supply unit that supplies a liquefied gas having a temperature not higher than a glass transition temperature of the binder; and a liquefied gas supplied from the supply unit And a scraper that removes the active material mixture layer that has become a temperature equal to or lower than the glass transition temperature of the binder.

  When the temperature of the active material mixture layer becomes equal to or lower than the glass transition temperature of the binder by the liquefied gas supplied from the supply unit, the binder is vitrified and the active material mixture layer becomes brittle. Moreover, a strip | belt-shaped metal foil and an active material mixture layer shrink | contract because an electrode material is cooled with the liquefied gas from a supply part. At this time, due to the difference between the linear expansion coefficient of the active material mixture layer and the linear expansion coefficient of the strip metal foil, a difference occurs between the contraction amount of the strip metal foil and the contraction amount of the active material mixture layer. Thereby, the force which peels mutually acts on the interface of a strip | belt-shaped metal foil and an active material mixture layer.

  Therefore, a part of the active material mixture layer can be easily removed from the electrode material by scraping the portion where the temperature of the active material mixture layer is equal to or lower than the glass transition temperature of the binder with the liquefied gas. . As described above, when the temperature of the active material mixture layer is set to be equal to or lower than the glass transition temperature of the binder with the liquefied gas, the active material mixture layer can be removed without providing moisture.

About the removal apparatus of the said active material mixture layer, you may provide the heating part which heats the residual part which is not removed by the said scraper among the said active material mixture layers.
The remaining portion that is not removed by the scraper is a portion that is used as an electrode material and becomes an electrode. By heating the remaining portion, it is possible to suppress the remaining portion from being cooled by the liquefied gas, and to prevent the remaining portion from peeling off from the strip-shaped metal foil.

  About the said active material mixture layer removal apparatus, when removing the said active material mixture layer, the surface of the said scraper which opposes the said remaining part is provided with a Peltier device, and the said Peltier device has an endothermic surface to the said scraper. And the heat generating surface may serve as the heating unit.

According to this, the remaining portion can be heated on the heat generating surface while the scraper is cooled by the heat absorbing surface of the Peltier element.
An active material mixture layer removing method that solves the above problems is based on an electrode material in which an active material mixture layer formed by applying an active material mixture containing a binder is provided on at least one surface of a strip-shaped metal foil. An active material mixture layer removing method for removing a part of a mixture layer, wherein a liquefied gas having a temperature equal to or lower than a glass transition temperature of the binder is supplied, and the glass transition temperature of the binder or less is supplied by the supplied liquefied gas The active material mixture layer having a temperature of 5 is removed with a scraper.

  According to this, a part of the active material mixture layer is easily removed from the electrode material by scraping the portion where the temperature of the active material mixture layer is equal to or lower than the glass transition temperature of the binder by the liquefied gas. be able to. By making the temperature of the active material mixture layer below the glass transition temperature of the binder with the liquefied gas, the active material mixture layer can be removed without providing moisture.

  According to the present invention, a part of the active material mixture layer can be removed from the electrode material without applying moisture.

(A) is a schematic block diagram of an electrode material manufacturing apparatus, (b) is a figure which shows the electrode material from which the defective part was removed with the cutting device, (c) is the 1st electrode material from which the active material mixture layer was removed, and The figure which shows a 2nd electrode material, (d) is a schematic block diagram which shows the electrode material which joined the 1st electrode material and the 2nd electrode material. The schematic block diagram which shows the removal apparatus of an active material mixture layer. The perspective view of a scraper. (A) is a figure which shows the effect | action of the removal apparatus of an active material mixture layer, (b) is a figure which shows the electrode material from which the removal part was removed with the removal apparatus of the active material mixture layer. (A) is sectional drawing which shows the electrode material which joined the 1st electrode material which has not removed the active material mixture layer, and the 2nd electrode material, (b) is the 1st electrode material which removed the active material mixture layer Sectional drawing which shows the electrode material which joined 2nd electrode material and. The schematic block diagram which shows the modification of the removal apparatus of an active material mixture layer.

Hereinafter, an embodiment of an active material mixture layer removal apparatus and an active material mixture layer removal method will be described.
The electrode material is used for manufacturing positive and negative electrodes used in lithium ion secondary batteries. The electrode material is formed by applying an active material mixture to a long strip-shaped metal foil. An electrode can be obtained by cutting the electrode material according to the shape of the electrode.

  As shown in FIG. 1A, the electrode material manufacturing apparatus 10 includes a supply device 12 that supplies a long strip-shaped metal foil 31, and a coating device 16 that applies an active material mixture to the strip-shaped metal foil 31. And a winding device 14 that winds up the electrode material 33.

  The supply device 12 includes a supply reel 13. A strip-shaped metal foil 31 is wound around the supply reel 13. The supply reel 13 rotates to send out the strip-shaped metal foil 31. As the strip-shaped metal foil 31, for example, a copper foil is used when a negative electrode is manufactured, and an aluminum foil is used when a positive electrode is manufactured. The winding device 14 includes a winding reel 15. The take-up reel 15 rotates to take up the electrode material 33. The strip-shaped metal foil 31 is conveyed from the supply reel 13 toward the take-up reel 15 by the rotation of the take-up reel 15 and the supply reel 13.

  Two coating apparatuses 16 are provided with the band-shaped metal foil 31 interposed therebetween. Each coating apparatus 16 forms the active material mixture layer 32 on both surfaces of the strip metal foil 31 by applying the active material mixture continuously in the longitudinal direction of the strip metal foil 31. The active material mixture is obtained by kneading an active material, a solvent, a thickener, a conductive aid, a binder and the like. Polyvinylidene fluoride is used as the binder of this embodiment.

  The electrode material manufacturing apparatus 10 is arranged downstream of the coating apparatus 16 in the transport direction of the strip-shaped metal foil 31, and inspects the defective portion 34 of the electrode material 33, and in the transport direction of the strip-shaped metal foil 31, And a cutting device 18 that is disposed downstream of the inspection device 17 and cuts the defective portion 34. The defective portion 34 of the electrode material 33 is, for example, a portion where the thickness of the active material mixture layer 32 applied to the strip-shaped metal foil 31 is insufficient or a portion where the thickness of the active material mixture layer 32 is excessive. . The inspection device 17 is, for example, a device that performs inspection by image processing or a device that performs inspection by X-rays. When the defective portion 34 is detected by the inspection device 17, the cutting device 18 cuts the two portions sandwiching the defective portion 34 from the longitudinal direction of the electrode material 33 over the entire short direction. The defective portion 34 is removed by cutting with the cutting device 18.

  The electrode material manufacturing apparatus 10 includes a roll press 19 downstream of the cutting device 18 in the transport direction of the strip-shaped metal foil 31. The roll press 19 includes a pair of rollers 20. When the electrode material 33 passes between the rollers 20, the density of the active material mixture layer 32 is increased. The interval between the rollers 20 is set so that the active material mixture layer 32 can have a predetermined thickness.

  The electrode material 33 taken up by the take-up device 14 is then supplied to an electrode manufacturing apparatus that cuts the electrode material 33 into an electrode shape. The electrode manufacturing apparatus manufactures an electrode by cutting the electrode material 33 being conveyed.

  By the way, as shown in FIG.1 (b), when the electrode material 33 is cut | disconnected by the cutting device 18, the electrode material 33 will be divided | segmented into the 1st electrode material 41 and the 2nd electrode material 42 in the cut | disconnected location. In the present embodiment, in the conveying direction of the strip-shaped metal foil 31, the portion upstream of the cut portion is the first electrode material 41, and the portion downstream of the cut portion is the second electrode material 42. And

  When the electrode material 33 is divided, the first electrode material 41 cannot be taken up by the take-up reel 15 and the strip-shaped metal foil 31 cannot be conveyed. For this reason, it is necessary to join the first electrode material 41 and the second electrode material 42 after removing the defective portion 34. In order to join the electrode materials 41, 42, as shown in FIG. 1C, the active material mixture layer removal device 50 (removal device 50 in the figure) includes each of the active material mixture layers 32. By removing a portion located at one end in the longitudinal direction of the electrode materials 41 and 42, an exposed portion 43 is formed in each electrode material 41 and 42. Therefore, in this embodiment, the electrode materials from which the active material mixture layer 32 is removed are the electrode materials 41 and 42. In addition, the exposed part 43 of this embodiment is a part which both surfaces of the strip | belt-shaped metal foil 31 exposed.

  After the exposed portion 43 is formed, the first electrode material 41 and the second electrode material 42 are joined by the joining device 81 as shown in FIG. Thereby, the electrode material 33 in which the first electrode material 41 and the second electrode material 42 are joined can be obtained. As the joining device 81, it is sufficient if the exposed portions 43 can be joined together. For example, a device that performs electrical resistance welding, solid phase joining, ultrasonic welding, joining by caulking, brazing, or the like is used. Hereinafter, the removal device 50 for the active material mixture layer will be described. In addition, in the active material mixture layer 32 of each electrode material 41 and 42, the part removed by the active material mixture layer removing apparatus 50, that is, the active material provided at one end in the longitudinal direction of each electrode material 41 and 42. The mixture layer 32 is a removal portion 44, and the portion that is not removed by the active material mixture layer removal apparatus 50 is a residual portion 45.

  As shown in FIGS. 2 and 3, the active material mixture layer removing apparatus 50 includes two scrapers 51 and a first actuator 53 that moves each scraper 51. The scraper 51 is made of metal and has a flat plate shape. The scraper 51 includes a rectangular main body 54 and a tip 52 that is continuous with one side of the main body 54. The distal end portion 52 becomes thinner from the main body portion 54 toward the distal end of the distal end portion 52. Of the directions along the thickness direction end faces of the main body 54, the width W1 of the front end 52 is the short direction of the strip-shaped metal foil 31 when the direction perpendicular to the direction from the main body 54 toward the front end 52 is the width direction. The active material mixture layer 32 has a dimension W2 or more.

  Each scraper 51 is provided with the electrode materials 41 and 42 sandwiched so that the width direction of the scraper 51 and the short direction of the strip-shaped metal foil 31 are the same direction. Each scraper 51 is arranged such that the tip 52 faces the active material mixture layer 32 and the thickness direction of the scraper 51 and the thickness direction of the strip-shaped metal foil 31 cross each other at an angle. Thereby, the scraper 51 is disposed so as to be inclined toward the remaining portion 45.

  The first actuator 53 moves the scraper 51 in a direction along the surface of the strip-shaped metal foil 31. The first actuator 53 of this embodiment moves the scraper 51 in the longitudinal direction of the strip-shaped metal foil 31. When the scraper 51 moves in the longitudinal direction of the strip-shaped metal foil 31, the tip end portion 52 is bitten to the vicinity of the strip-shaped metal foil 31.

  The active material mixture layer removing apparatus 50 includes two supply nozzles 61 as supply units, and a second actuator 63 that moves the supply nozzle 61. A supply source 62 that supplies liquefied gas to the supply nozzle 61 is connected to the supply nozzle 61. The supply source 62 includes a control unit. The control unit controls the supply and stop of the liquefied gas to the supply nozzle 61, the flow rate of the liquefied gas supplied to the supply nozzle 61, and the like. The supply source 62 supplies the supply nozzle 61 with a liquefied gas that is equal to or lower than the glass transition temperature (glass transition temperature) of the binder contained in the active material mixture layer 32. As the liquefied gas, a liquefied gas having a temperature equal to or lower than the glass transition temperature (−39 ° C.) of polyvinylidene fluoride used as a binder is used. As the liquefied gas, for example, liquid nitrogen (−196 degrees), liquid helium (−269 degrees), or the like is used.

  Each supply nozzle 61 is disposed with the electrode materials 41 and 42 sandwiched from both sides in the thickness direction of the strip-shaped metal foil 31. The supply nozzle 61 is disposed at a position where the liquefied gas can be supplied toward the removal portion 44.

  The second actuator 63 moves the supply nozzle 61 in the same direction as the moving direction of the scraper 51. The second actuator 63 is driven together with the driving of the first actuator 53 to move the supply nozzle 61 in the same direction as the scraper 51. As described above, when the scraper 51 moves in the longitudinal direction of the strip-shaped metal foil 31, the leading end 52 is bitten to the vicinity of the strip-shaped metal foil 31.

  The active material mixture layer removing apparatus 50 includes a heating unit 71 that heats the remaining portion 45. The heating unit 71 is, for example, an electronic heater. The heating unit 71 is disposed along the surface of the remaining portion 45. Specifically, the heating unit 71 is disposed at a position where the portion of the residual portion 45 where the temperature decreases due to the influence of the liquefied gas can be warmed.

Next, the active material mixture layer removing method using the active material mixture layer removing apparatus 50 of the present embodiment will be described together with the operation.
When the active material mixture layer 32 is removed from each electrode material 41, 42, liquefied gas is supplied from the supply nozzle 61 to the removal portion 44. Thereby, the temperature of the removal part 44 becomes below the glass transition temperature of a binder. When the binder is vitrified, the removed portion 44 becomes brittle.

  Furthermore, the electrode materials 41 and 42 contract by cooling with the liquefied gas. At this time, due to the difference between the linear expansion coefficient of the strip-shaped metal foil 31 and the linear expansion coefficient of the active material mixture layer 32, the contraction amount of the strip metal foil 31 and the contraction amount of the active material mixture layer 32 are reduced. There is a difference. Thereby, the force which is going to peel mutually acts on the interface of the strip | belt-shaped metal foil 31 and the active material mixture layer 32. FIG.

  Next, the leading end 52 of the scraper 51 is inserted into the removal portion 44 by a moving mechanism (for example, an actuator or the like) not shown. And the front-end | tip part 52 of the scraper 51 is located near the strip | belt-shaped metal foil 31. FIG.

  Next, as shown in FIG. 4A, the scraper 51 is moved in the direction opposite to the remaining portion 45 in the longitudinal direction of the strip-shaped metal foil 31 by the first actuator 53. The removal portion 44 is scraped off from the strip-shaped metal foil 31 by being pushed by the scraper 51. And the removal part 44 is extruded from the short edge of the strip | belt-shaped metal foil 31, and the removal part 44 is removed from the strip | belt-shaped metal foil 31. FIG. As shown in FIG. 4B, when the removal portion 44 is removed, exposed portions 43 in which both surfaces of the strip-shaped metal foil 31 are exposed are formed in the electrode materials 41 and 42.

  As the scraper 51 is moved by the first actuator 53, the supply nozzle 61 is also moved in the same direction by the second actuator 63. While the removal by the scraper 51 is being performed, the liquefied gas is continuously supplied from the supply nozzle 61 to the removal portion 44.

  While supplying the liquefied gas from the supply nozzle 61, the heating unit 71 heats the remaining portion 45. Thereby, it is suppressed that the temperature of the residual part 45 falls. By heating the residual portion 45 that is used as the electrode material 33 and becomes an electrode, the residual portion 45 is prevented from being cooled by the liquefied gas, and the linear expansion coefficient of the active material mixture layer 32 and the strip-shaped metal foil 31 are suppressed. It is possible to suppress the remaining portion 45 from peeling off from the strip-shaped metal foil 31 due to the difference from the linear expansion coefficient.

Therefore, according to the above embodiment, the following effects can be obtained.
(1) Since the active material mixture layer 32 is made brittle by the liquefied gas, the active material mixture layer 32 can be easily removed by the scraper 51. Since the active material mixture layer 32 can be removed without applying moisture to the active material mixture layer 32 as in the case of removing the active material mixture layer 32 by ultrasonic waves, the electrode material 33 of the present embodiment. In the electrode obtained from the above, the formation of the SEI film due to moisture is suppressed, and the deterioration of the performance is suppressed.

  (2) Heating the remaining portion 45 with the heating unit 71 prevents the remaining portion 45 from being cooled by the influence of the liquefied gas. Therefore, it can suppress that the residual part 45 peels from the strip | belt-shaped metal foil 31 by cooling, and can suppress that the part which can be used as an electrode decreases.

  (3) As shown to Fig.5 (a), the electrode material 100 is comprised by joining the 1st electrode material 41 and the 2nd electrode material 42 which have not removed the active material mixture layer 32 with an adhesive agent. It is also possible. However, when the first electrode material 41 and the second electrode material 42 are joined without removing the active material mixture layer 32, each electrode material 41 is a part where the first electrode material 41 and the second electrode material 42 overlap. , 42 are overlapped with each other. Therefore, the maximum thickness T1 in the electrode material 100 obtained by joining the first electrode material 41 and the second electrode material 42 from which the active material mixture layer 32 has not been removed is greater than the thickness of each electrode material 41, 42.

  As shown in FIG. 5B, when the exposed portions 43 are joined as in the present embodiment, the active material mixture layer 32 does not overlap at the portion where the first electrode material 41 and the second electrode material 42 overlap. . The maximum thickness T2 of the electrode material 33 obtained by joining the first electrode material 41 and the second electrode material 42 from which the active material mixture layer 32 has been removed is the same as that of the electrode materials 41 and 42.

  It is possible to suppress the maximum thickness of the electrode material 33 from becoming excessively large, and to suppress damage to the roller 20 when the electrode material 33 is passed between the rollers 20. Further, when the electrode is cut out from the electrode material 33 being conveyed by the rotary die cutter, the rotary die cutter can be prevented from being damaged.

In addition, you may change embodiment as follows.
As shown in FIG. 6, the active material mixture layer removing apparatus 50 may include a Peltier element 90 having a first surface 91 and a second surface 92 that perform opposite actions of heat absorption and heat generation. The first surface 91 of the Peltier device 90 is fixed to the surface facing the remaining portion 45 when the active material mixture layer 32 is removed, among the surfaces in the thickness direction of the scraper 51, so that the Peltier device 90 is made of the scraper 51. Is attached. In a state where the tip 52 of the scraper 51 is inserted into the active material mixture layer 32, the second surface 92 of the Peltier element 90 faces the remaining portion 45. When the active material mixture layer 32 is removed by the scraper 51, the Peltier element 90 is driven to cause the first surface 91 to absorb heat and cause the second surface 92 to generate heat. As a result, the first surface 91 becomes an endothermic surface, and the second surface 92 becomes an exothermic surface. The scraper 51 is cooled by the first surface 91 absorbing heat. Thereby, in addition to the liquefied gas, the active material mixture layer 32 can be cooled via the scraper 51. Further, the second surface 92 functions as a heating unit and can heat the remaining portion 45.

O The liquefied gas may be supplied from the supply nozzle 61 toward the scraper 51, and the temperature of the removal portion 44 may be made equal to or lower than the glass transition temperature of the binder via the scraper 51.
O When removing the active material mixture layer 32, the supply of the liquefied gas may be stopped after supplying the liquefied gas and setting the temperature of the active material mixture layer 32 to be equal to or lower than the glass transition temperature of the binder. Then, the removal portion 44 may be removed by the scraper 51 while the supply of the liquefied gas is stopped. That is, it is not necessary to supply the liquefied gas during the removal of the active material mixture layer 32 by the scraper 51. In this case, since it is not necessary to move the supply nozzle 61, the second actuator 63 may not be provided.

  When removing the removal portion 44 by the scraper 51, the removal portion 44 is removed by moving the electrode materials 41 and 42 in the longitudinal direction while the scraper 51 and the supply nozzle 61 are fixed at a fixed position. May be.

  The active material mixture layer removing device 50 may have a configuration in which one supply nozzle 61 and one scraper 51 are provided. In this case, using one supply nozzle 61 and the scraper 51, the removal portions 44 provided on both surfaces of the strip-shaped metal foil 31 are sequentially removed.

  Each electrode material 41, 42 may include an active material mixture layer 32 on one side of the strip-shaped metal foil 31. In this case, the active material mixture layer removing apparatus 50 includes one supply nozzle 61 and one scraper 51.

  O You may remove the removal part 44 from only one among the active material mixture layers 32 provided in both surfaces of the strip | belt-shaped metal foil 31. FIG. In this case, the exposed portions 43 of the electrode materials 41 and 42 are portions where only one surface of the strip-shaped metal foil 31 is exposed. In this case, the surfaces of the exposed portion 43 from which the removed portion 44 is removed are faced to each other.

  As the binder, polytetrafluoroethylene, styrene butadiene rubber or the like may be used. In this case, a liquefied gas having a temperature not higher than the glass transition temperature of each binder is supplied.

  The first actuator 53 may move the scraper 51 in the short direction of the strip-shaped metal foil 31. In this case, the scraper 51 extrudes a part of the removal portion 44 from one long edge of the strip-shaped metal foil 31 and then extrudes the remaining portion of the removal portion 44 from the other long edge of the strip-shaped metal foil 31.

-The heating part 71 does not need to be provided. In this case, it is only necessary not to use a portion of the remaining portion 45 close to the exposed portion 43 as an electrode.
O Although the removal apparatus 50 of the active material mixture layer of embodiment formed the exposed part 43 in order to join each electrode material 41 and 42, it is not restricted to this. An electrode provided with an active material layer on at least one surface of a metal foil is an uncoated material that does not include an active material layer for the purpose of electrically joining a plurality of electrodes or electrically connecting to a terminal of a power storage device. The part is provided on a part of the metal foil. In order to form an uncoated part, for example, an exposed part is provided along the long edge of the strip-shaped metal foil 31, and the exposed part is punched to form an uncoated part. In order to form an exposed portion to be used as an uncoated portion, after applying the active material mixture over both surfaces of the strip-shaped metal foil 31, the strip-shaped metal foil 31 using the active material mixture layer removing device 50 is applied. The active material mixture layer 32 may be removed from the portion along the long edge.

  DESCRIPTION OF SYMBOLS 31 ... Strip | belt-shaped metal foil, 32 ... Active material mixture layer, 41 ... 1st electrode material, 42 ... 2nd electrode material, 44 ... Removal part, 45 ... Residual part, 50 ... Removal apparatus of active material mixture layer, 51 ... scraper, 61 ... supply nozzle (supply part), 71 ... heating part, 90 ... Peltier element, 91 ... first surface (heat-absorbing surface), 92 ... second surface (heat-generating surface).

Claims (4)

An active material mixture layer for removing a part of the active material mixture layer from an electrode material provided with an active material mixture layer formed by applying an active material mixture containing a binder on at least one surface of the strip-shaped metal foil. A removal device,
A supply unit for supplying a liquefied gas having a temperature equal to or lower than the glass transition temperature of the binder;
An apparatus for removing an active material mixture layer, comprising: a scraper that removes the active material mixture layer having a temperature equal to or lower than a glass transition temperature of the binder by the liquefied gas supplied from the supply unit.   The removal apparatus of the active material mixture layer of Claim 1 provided with the heating part which heats the remaining part which is not removed by the said scraper among the said active material mixture layers. A Peltier element is provided on the surface of the scraper that faces the remaining portion when the active material mixture layer is removed,
The apparatus for removing an active material mixture layer according to claim 2, wherein the Peltier element has a heat absorption surface thermally coupled to the scraper, and a heat generation surface serves as the heating unit. An active material mixture layer for removing a part of the active material mixture layer from an electrode material provided with an active material mixture layer formed by applying an active material mixture containing a binder on at least one surface of the strip-shaped metal foil. A removal method,
Supplying a liquefied gas having a temperature equal to or lower than the glass transition temperature of the binder;
A method for removing an active material mixture layer, wherein a scraper removes the active material mixture layer having a temperature equal to or lower than a glass transition temperature of the binder by a supplied liquefied gas.

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