Roll press apparatus and method for producing compressed strip-shaped electrode sheet
A roll press apparatus includes a first press roll and a second press roll. The first press roll includes a first contact part configured to contact an active material portion of a strip-shaped electrode sheet and a second contact part configured to contact an active-material absent portion of the strip-shaped electrode sheet. The second contact part has a large frictional-force generating form that causes a larger frictional force to be generated between the second contact part and the active-material absent portion of the strip-shaped electrode sheet than an imaginary frictional force which would be generated if the active-material absent portion of the strip-shaped electrode sheet were made to contact the first contact part.
1 . A roll press apparatus configured to roll-press an uncompressed strip-shaped electrode sheet, which is provided with: a strip-shaped current collecting foil; and an uncompressed strip-shaped active material layer located on the strip-shaped current collecting foil and extended in a longitudinal direction of the strip-shaped current collecting foil, while conveying the uncompressed strip-shaped electrode sheet in the longitudinal direction to compress uncompressed strip-shaped the active material layer of the uncompressed strip-shaped electrode sheet,
the uncompressed strip-shaped electrode sheet including:
an uncompressed strip-shaped active material portion extended in the longitudinal direction and including the uncompressed strip-shaped active material layer in a thickness direction of the strip-shaped current collecting foil; and
a strip-shaped active-material absent portion extended in the longitudinal direction and arranged adjacent to the uncompressed strip-shaped active material portion in a width direction of the strip-shaped current collecting foil, wherein the strip-shaped active-material absent portion does not include the uncompressed strip-shaped active material layer in the thickness direction and has a thinner thickness than the uncompressed strip-shaped active material portion,
wherein the roll press apparatus comprises a first press roll and a second press roll, which are arranged in parallel to each other with a gap,
the first press roll is placed in contact with the uncompressed strip-shaped electrode sheet so that the uncompressed strip-shaped electrode sheet is wrapped around the first press roll at a wrap angle larger than a zero degree and includes:
a first contact part, around which the uncompressed strip-shaped active material portion of the uncompressed strip-shaped electrode sheet is wrapped at the wrap angle; and
a second contact part, around which the strip-shaped active-material absent portion of the uncompressed strip-shaped electrode sheet is wrapped at the wrap angle, and
the second contact part of the first press roll is configured, differently from the first contact part, to have a large frictional-force generating form that causes a larger frictional force to be generated between the second contact part and the strip-shaped active-material absent portion of the uncompressed strip-shaped electrode sheet than an imaginary frictional force which would be generated if the first contact part of the first press roll were made to contact the active-material absent portion of the strip-shaped electrode sheet, and
while only the second contact part of the first press roll is in direct contact with the strip-shaped active-material absent portion of the uncompressed strip-shaped electrode sheet at the wrap angle, the uncompressed strip-shaped active material portion of the uncompressed strip-shaped electrode sheet is roll-pressed by the first contact part of the first press roll and the second press roll.
2 . The roll press apparatus according to claim 1 , wherein the second contact part of the first press roll has the large frictional-force generating form with a larger roll diameter than a roll diameter of the first contact part.
3 . The roll press apparatus according to claim 1 , wherein the second contact part of the first press roll has the large frictional-force generating form with a larger surface roughness than a surface roughness of the first contact part.
4 . The roll press apparatus according to claim 3 , wherein the second contact part of the first press roll has the large frictional-force generating form with a larger roll diameter than a roll diameter of the first contact part.
5 . A method for producing a compressed strip-shaped electrode sheet including a strip-shaped current collecting foil and a compressed strip-shaped active material layer compressed in a thickness direction of the current collecting foil, wherein
the method comprises:
electrode-sheet forming of forming an uncompressed strip-shaped electrode sheet provided with the strip-shaped current collecting foil and an uncompressed strip-shaped active material layer located on the strip-shaped current collecting foil and extended in a longitudinal direction of the strip-shaped current collecting foil, the uncompressed strip-shaped electrode sheet including:
an uncompressed strip-shaped active material portion extended in the longitudinal direction and including the uncompressed strip-shaped active material layer in the thickness direction of the strip-shaped current collecting foil; and
a strip-shaped active-material absent portion extended in the longitudinal direction and arranged adjacent to the uncompressed strip-shaped active material portion in a width direction of the strip-shaped current collecting foil, wherein the strip-shaped active-material absent portion does not include the uncompressed strip-shaped active material portion in the thickness direction and has a thinner thickness than the uncompressed strip-shaped active material portion; and
pressing of roll-pressing the uncompressed strip-shaped electrode sheet by a first press roll and a second press roll, which are arranged in parallel to each other with a roll gap, while conveying the uncompressed strip-shaped electrode sheet in the longitudinal direction to form the compressed strip-shaped electrode sheet provided with the compressed strip-shaped active material layer,
the first press roll is placed in contact with the uncompressed strip-shaped electrode sheet so that the uncompressed strip-shaped electrode sheet is wrapped around the first press roll at a wrap angle larger than a zero degree and includes:
a first contact part, around which the uncompressed strip-shaped active material portion of the uncompressed strip-shaped electrode sheet is wrapped at the wrap angle; and
a second contact part, around which the strip-shaped active-material absent portion of the uncompressed strip-shaped electrode sheet is wrapped at the wrap angle,
the second contact part of the first press roll is configured, differently from the first contact part, to have a large frictional-force generating form that causes a larger frictional force to be generated between the second contact part and the strip-shaped active-material absent portion of the uncompressed strip-shaped electrode sheet than an imaginary frictional force which would be generated if the first contact part of the first press roll were made to contact the strip-shaped active-material absent portion of the uncompressed strip-shaped electrode sheet, and
the pressing is performed to roll-press the uncompressed strip-shaped active material portion of the uncompressed strip-shaped electrode sheet with the first contact part of the first press roll and the second press roll in which the second contact part of the first press roll is located apart from the uncompressed strip-shaped active-material portion of the uncompressed strip-shaped electrode sheet, while the second press roll is placed apart from the strip-shaped active-material absent portion of the uncompressed strip-shaped electrode sheet, and only the second contact part of the first press roll is in direct contact with the strip-shaped active-material absent portion of the uncompressed strip-shaped electrode sheet at the wrap angle.
6 . The method for producing a compressed strip-shaped electrode sheet according to claim 5 , wherein the second contact part of the first press roll has the large frictional-force generating form with a larger roll diameter than a roll diameter of the first contact part.
7 . The method for producing a compressed strip-shaped electrode sheet according to claim 5 , wherein the second contact part of the first press roll has the large frictional-force generating form with a larger surface roughness than a surface roughness of the first contact part.
8 . The method for producing a compressed strip-shaped electrode sheet according to claim 7 , wherein the second contact part of the first press roll has the large frictional-force generating form with a larger roll diameter than a roll diameter of the first contact part.