JP2018020298A - Roll film forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a roll film forming device which can reduce a degree of unevenness (a maximum dimension of the unevenness) in a width direction at both end parts of a film-like coating material.SOLUTION: A coating material 6 stored in a storage part 4 is drawn to a clearance of a pair of rolls 1, 2 by rotation of the pair of rolls 1, 2 and is supplied to the clearance of the pair of rolls 1, 2 while restricting a width dimension E by a pair of side wall parts 4b, 4c, and is formed in a film shape by passing through the clearance of the pair of rolls 1, 2. The coating material 6 formed in the film shape coats a surface of an object to be coated 7. A roll film forming device 20 includes pressing parts 30, 40 which apply a load F toward sides of the pair of rolls 1, 2 on coating materials 6b, 6c on both end parts, which are positioned on both end parts in the storage part 4 in a width direction DW, out of the coating material 6 stored in the storage part 4.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a roll film forming apparatus having a pair of rolls.

  In Patent Document 1, a pair of rolls arranged in parallel with each other with a predetermined gap and rotating, and a plurality of wet granulation bodies (for example, electrode active materials bound together) are arranged immediately above the pair of rolls. A roll film forming apparatus is disclosed that includes an accommodating portion that accommodates a coating material (electrode mixture) made of a material and a solvent and granulated. The accommodating portion is a pair of side wall portions that are spaced apart from each other in the width direction of the roll, and regulates the dimension in the width direction (coinciding with the axial direction of the roll) of the coating material supplied to the gap between the pair of rolls. It has a pair of side wall parts. In this roll film forming apparatus, a pair of rolls is formed such that the coating material accommodated in the accommodating part is drawn into the gap between the pair of rolls by the rotation of the pair of rolls while the width dimension is regulated by the pair of side wall parts. The film is formed into a film by passing through the gap between the pair of rolls, and the coating material formed into a film is applied onto the surface of the object to be coated (current collector foil).

Japanese Patent Laid-Open No. 2006-112754

  By the way, among the coating materials accommodated in the accommodating part, it is located at both ends in the accommodating part in the width direction (coincident with the axial direction of the pair of rolls) (in other words, adjacent to each of the pair of side wall parts). The both-end coating material tended to have a higher porosity than the coating material located between them (intermediate portion). When there is a gap in the coating material at both ends, the supply of the coating material to the gap between the pair of rolls may be interrupted at the gap.

  The portion where the supply of the coating material at both ends to the gap between the pair of rolls is interrupted does not exist in the coating material formed into a film by passing through the gap between the pair of rolls (referred to as a film-like coating material). It becomes a space | gap part and becomes a recessed part (part dented inside the film-form coating material about the width direction) about the width direction. For this reason, in the film-form coating material, both end portions in the width direction may be uneven in the width direction.

  Specifically, the larger the voids present in the coating material at both ends (the higher the porosity), the greater the degree of unevenness in the width direction at both ends of the film-like coating material, The maximum value of the distance in the width direction between the two). When the degree of unevenness in the width direction (maximum unevenness dimension) at both ends of the film-shaped coating material is large, film formation is poor. For this reason, there has been a demand for a roll film forming apparatus that can reduce the degree of unevenness in the width direction (maximum unevenness dimension) at both ends of the film-form coating material.

  The present invention has been made in view of the present situation, and the degree of unevenness in the width direction at both ends of a film-shaped coating material (coating material formed into a film by passing through a gap between a pair of rolls) ( An object of the present invention is to provide a roll film forming apparatus capable of reducing the maximum unevenness dimension).

  One aspect of the present invention includes a pair of rolls that are arranged in parallel with each other with a gap therebetween and rotate, and a container that is disposed immediately above the pair of rolls and accommodates a coating material composed of a plurality of wet granules. And the accommodating portion is a pair of side wall portions spaced apart in the width direction of the roll, and the dimension in the width direction of the coating material supplied to the gap between the pair of rolls The coating material that has a pair of side walls to be regulated and is accommodated in the gap between the pair of rolls by rotation of the pair of rolls while the width of the coating material is regulated by the pair of side walls. It is supplied to the gap between the pair of rolls so as to be drawn into a film by passing through the gap between the pair of rolls, and the coating material formed into a film is applied onto the surface of the object to be coated. Roll film forming equipment And the press which adds a load toward the pair of roll side with respect to the both ends coating material located in the both ends in the said accommodating part about the said width direction among the said coating materials accommodated in the said accommodating part 1 is a roll film forming apparatus including a section.

  The roll film forming apparatus described above is positioned at both end portions in the accommodating portion in the width direction (coincident with the axial direction of the pair of rolls) of the coating material accommodated in the accommodating portion (in other words, a pair of side wall portions) A pressing portion for applying a load toward the pair of rolls (from the upper side to the lower side) with respect to the both-end coating material (adjacent to each other). By applying a load toward the pair of rolls (from the upper side to the lower side) with respect to the coating material at both ends by this pressing part, the porosity of the coating material at both ends is reduced and accommodated in the accommodating part. It is possible to reduce (reduce) the gaps in the applied material at both ends.

  Thereby, the space | gap in the both-ends coating material supplied to the gap | interval of a pair of rolls can be made small, and the magnitude | size of the space | gap (gap width dimension) which interrupts supply to the gap | interval of a pair of rolls is made small. be able to. Thereby, in the coating material (film-shaped coating material) formed into a film by passing through the gap between the pair of rolls, the width direction dimension (width direction dimension of the width-direction recess) where the coating material does not exist is reduced. can do. Accordingly, with respect to the coating material (film-shaped coating material) formed into a film by passing through the gap between the pair of rolls, the degree of unevenness in the width direction (maximum unevenness dimension) at both ends in the width direction can be reduced. . The maximum unevenness dimension means the maximum value of the distance in the width direction between the recess and the protrusion.

  The wet granulated body refers to a substance (granular body) in which the solvent is held (absorbed) by solute particles and these are aggregated (bound). Examples of the wet granulated material include those obtained by mixing and granulating an electrode active material, a binder, and a solvent. This wet granulated body is a substance (granular body) in which the solvent is held (absorbed) by the electrode active material particles and the binder, and these are aggregated (bound). In this case, the coating material is an electrode mixture composed of a plurality of wet granulation bodies that are granulated by mixing an electrode active material, a binder, and a solvent, and the coating object is a current collector foil.

1 is a schematic side view of a roll film forming apparatus according to an embodiment. It is a perspective view of the roll film-forming apparatus. It is a top view of the roll film forming apparatus. It is a correlation diagram of the width dimension of a pressing member, and an uneven | corrugated maximum dimension. It is a correlation diagram of the load by a press part, and uneven | corrugated largest dimension. It is a figure explaining the space | gap when the negative electrode compound material (coating material) which consists of a wet granulation body is formed into a film, and is equivalent to the A section enlarged view of FIG. It is a figure explaining the unevenness | corrugation in the both ends of the width direction of a film-form negative electrode compound material (film-form coating material), and is equivalent to the B view enlarged view of FIG. It is another figure explaining the unevenness | corrugation in the both ends of the width direction of a film-form negative electrode compound material (film-form coating material).

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, embodiments of the invention will be described in detail with reference to the drawings.
In this embodiment, the example which used the roll film-forming apparatus for manufacture of the electrode sheet (specifically negative electrode sheet) of a lithium ion secondary battery is shown. More specifically, as will be described later, the roll film forming apparatus of the present embodiment is used in the film forming process in the manufacturing process of the negative electrode sheet of the lithium ion secondary battery.

  Therefore, in this embodiment, the wet granulated body becomes the wet granulated body 16 obtained by granulating the electrode active material (specifically, the negative electrode active material), the binder, and the solvent. The wet granulated body 16 is a substance (granular body) in which the solvent is held (absorbed) by the particles of the electrode active material (negative electrode active material) and the binder (aggregated). In the present embodiment, the coating material is an electrode mixture (specifically, the negative electrode mixture 6) made of the wet granulated body 16. Further, the object to be coated becomes the current collector foil 7.

  In this embodiment, a powdery carbon material (for example, graphite) is used as the negative electrode active material. Moreover, water is used as a solvent. Moreover, CMC (carboxymethylcellulose) is used as a binder.

FIG. 1 is a schematic side view of a roll film forming apparatus 20 according to the embodiment. FIG. 2 is a perspective view of the roll film forming apparatus 20. FIG. 3 is a top view of the roll film forming apparatus 20. 3, illustration of the connection part 32 of the 1st press part 30 and the connection part 42 of the 2nd press part 40 is abbreviate | omitted.
As shown in FIG. 1, the roll film forming apparatus 20 of the present embodiment includes a pair of rolls (first roll 1 and second roll 2) that are arranged in parallel with each other with a gap therebetween, and a pair of rolls ( The first roll 1 and the second roll 2) are disposed immediately above the housing 4 and the third roll 3 is provided for housing the negative electrode mixture 6 (coating material) composed of a plurality of wet granulation bodies 16. Yes.

  The 1st roll 1 and the 2nd roll 2 are arrange | positioned along with the horizontal direction (left-right direction in FIG. 1). On the other hand, the second roll 2 and the third roll 3 are arranged side by side in the vertical direction (vertical direction in FIG. 1). Further, the first roll 1 and the second roll 2 face each other with a slight gap. Similarly, the second roll 2 and the third roll 3 face each other with a slight gap.

  Further, the rotation directions of these three rolls 1 to 3 are set so that the rotation directions of two adjacent (facing) rolls are opposite to each other as shown by arrows in FIGS. These two rolls are set to rotate in the forward direction. And in the facing location of the 1st roll 1 and the 2nd roll 2, the surface of these rolls moves downward by rotation. Moreover, in the facing location of the 2nd roll 2 and the 3rd roll 3, the surface of these rolls moves rightward by rotation. Regarding the rotation speed, the moving speed of the surface of the roll due to the rotation is set to be the slowest in the first roll 1, the fastest in the third roll 3, and intermediate between them in the second roll 2.

  The accommodating part 4 has a pair of side wall parts (a first side wall part 4b and a second side wall part) that are spaced apart in the width direction DW (axial direction, vertical direction in FIG. 3) of the first roll 1 and the second roll 2. 4c), and a third side wall portion 4d and a fourth side wall portion 4e that are spaced apart from each other in the arrangement direction DL (left and right direction in FIG. 3) of the first roll 1 and the second roll 2. The housing 4 is an upper surface surrounded by the first side wall 4b, the second side wall 4c, the third side wall 4d, and the fourth side wall 4e (the surfaces of the first roll 1 and the second roll 2). A rectangular-shaped accommodation space is formed.

  The 1st side wall part 4b and the 2nd side wall part 4c are the same shape, comprise flat plate shape, and are arrange | positioned in parallel with the arrangement direction DL (left-right direction in FIG. 3) of the 1st roll 1 and the 2nd roll 2. FIG. . In addition, the lower end part of the 1st side wall part 4b and the 2nd side wall part 4c is circular arc shape along the surface of the 1st roll 1 and the 2nd roll 2, and contacts the surface of the 1st roll 1 and the 2nd roll 2 doing. The first side wall portion 4b and the second side wall portion 4c (a pair of side wall portions) are in the width direction of the negative electrode mixture 6 (coating material) supplied to the gap between the first roll 1 and the second roll 2 (a pair of rolls). The dimension E of the DW is restricted to a separation distance between the first side wall part 4b and the second side wall part 4c (an inner dimension in the width direction DW of the housing part 4).

  Moreover, the 3rd side wall part 4d and the 4th side wall part 4e are the same shape, comprise a rectangular flat plate shape, and are arrange | positioned in parallel with the width direction (up-down direction in FIG. 3) of the 1st roll 1 and the 2nd roll 2. ing. Note that the lower end portions of the third side wall portion 4d and the fourth side wall portion 4e are slightly separated from the surfaces of the first roll 1 and the second roll 2.

  A current collector foil 7 is stretched over the third roll 3. The current collector foil 7 is a metal foil (copper foil), and passes through the facing portion of the second roll 2 and the third roll 3 along with the rotation of the third roll 3, from the lower right to the upper right of the third roll 3. It is designed to be transported. Moreover, in the state where the current collector foil 7 is passed through the facing portion between the second roll 2 and the third roll 3, there is a slight gap between the second roll 2 and the current collector foil 7. Has been. That is, the gap between the second roll 2 and the third roll 3 (gap in the state where the current collector foil 7 is not present) is slightly wider than the thickness of the current collector foil 7.

  In such a roll film forming apparatus 20, the negative electrode mixture 6 (coating material) accommodated in the accommodating portion 4 has a width dimension E by the first side wall portion 4 b and the second side wall portion 4 c (a pair of side wall portions). The first roll is drawn into the gap between the first roll 1 and the second roll 2 by the rotation of the first roll 1 and the second roll 2 (a pair of rolls) while being regulated (the dimension in the width direction DW). It is supplied into the gap between the facing portions of the first roll 2 and the second roll 2. And it passes through the gap | interval of the 1st roll 1 and the 2nd roll 2, and is made into a film form, and becomes the film-form negative electrode compound material 8 (film-form coating material) (refer FIG. 1, FIG. 2).

  At this time, since the rotation speed of the second roll 2 is faster than that of the first roll 1, the wet granulated body 16 included in the negative electrode mixture 6 is more on the surface of the second roll 2 than the surface of the first roll 1. The surface of the second roll 2 is supported on the surface of the second roll 2 by being stretched to a greater extent and having a liquid crosslinking area on the surface of the second roll 2 that is larger than the surface of the first roll 1.

  The film-like negative electrode mixture 6 (film-like negative electrode mixture 8) carried on the surface of the second roll 2 is conveyed along with the rotation of the second roll 2 (see FIGS. 1 and 2). Then, the current collector foil 7 and the film-like negative electrode mixture 8 meet at the facing portion between the second roll 2 and the third roll 3. Thereby, the film-like negative electrode mixture 8 is transferred (attached) from the second roll 2 onto the surface of the current collecting foil 7 rotating together with the third roll 3 having a higher moving speed. In this way, the film-like negative electrode mixture 8 (coating material made into a film) is applied onto the surface of the current collector foil 7 (object to be applied). Thereby, the current collector foil 9 with the film-like negative electrode mixture in which the film-like negative electrode mixture 8 is formed on the current collector foil 7 is obtained.

  By the way, in the conventional roll film-forming apparatus, among the negative electrode mixture 6 (coating material) accommodated in the accommodating portion 4, the accommodating portion 4 in the width direction DW (coincides with the axial direction of the pair of rolls 1 and 2). Both end negative electrode composites 6b and 6c (both end coating materials) located at both ends (in other words, adjacent to each of the pair of side wall portions 4b and 4c) are positioned between them in the width direction DW (intermediate) The void ratio tended to be higher than that of the negative electrode mixture 6 (coating material) located in the part). For this reason, a relatively large gap 10A (a space in which the wet granulated body 16 does not exist) may exist inside the negative electrode composites 6b and 6c at both ends in the accommodating portion 4 (see FIG. 6).

As shown in FIG. 6, when the gap 10A exists inside the negative electrode composites 6b and 6c at both ends, the gap between the pair of rolls (the first roll 1 and the second roll 2) is located at the gap 10A. The supply of the negative electrode mixture 6 (coating material) may be temporarily interrupted.
FIG. 6 is a view corresponding to the enlarged view of part A in FIG. 1, in which both end negative electrode composites 6 b and 6 c (one end negative mix 6 b and the other end negative mix 6 c) are paired. It is a figure which shows a mode when passing the gap | interval of a roll (1st roll 1 and 2nd roll 2).

As shown in FIG. 6 and FIG. 7, the locations where the supply of both end negative electrode composites 6 b and 6 c (both end coating materials) to the gap between the pair of rolls (the first roll 1 and the second roll 2) are interrupted. In the negative electrode mixture 6 (film-like negative electrode mixture 8) formed into a film by passing through the gap between the pair of rolls 1 and 2, a gap portion 10B in which the negative electrode mixture 6 (wet granulated body 16) does not exist is formed. In the width direction DW, a concave portion G (a part of the end portion of the film-like negative electrode mixture 8 in the width direction DW that is recessed toward the center of the film-like negative electrode mixture 8 in the width direction DW).
FIG. 7 is a view corresponding to the enlarged view of B in FIG. 1, and is carried on the surface of the second roll 2 through a gap between a pair of rolls (first roll 1 and second roll 2). 3 is a plan view of the film-like negative electrode composite material 8. FIG.

  Therefore, as shown in FIGS. 7 and 8, in the film-like negative electrode mixture 8 (film-form coating material), both end portions 8b and 8c in the width direction DW (one end portion 8b in the width direction and the other end portion 8c in the width direction). ) May be uneven in the width direction DW. Specifically, the larger the gap 10A existing in the both-end negative electrode mixture 6b, 6c (both-end coating material) accommodated in the accommodating portion 4 (the higher the porosity), the more the membrane-like negative electrode mixture 8 tended to increase the degree of unevenness in the width direction DW at both ends 8b and 8c.

  Specifically, the maximum irregularity dimension D (the maximum value of the distance in the width direction DW between the concave portion G and the convex portion H at both ends 8b and 8c of the film-shaped negative electrode mixture 8 is shown in FIGS. 7 and 8. Tend to be large). If the maximum unevenness dimension D at both ends 8b, 8c of the film-like negative electrode mixture 8 is large, film formation is poor and the negative electrode sheet 19 (applied product) cannot be used properly. For this reason, there has been a demand for a roll film forming apparatus that can reduce the degree of unevenness (unevenness maximum dimension D) in the width direction DW at both ends 8b and 8c of the film-like negative electrode mixture 8.

  On the other hand, the roll film-forming apparatus 20 of this embodiment is a pair of roll 1 with respect to the both-ends negative electrode mixture 6b, 6c accommodated in the accommodating part 4, as shown in FIGS. , Pressing portions 30 and 40 for applying a load F (pressing load) toward the second side (from the top to the bottom). Specifically, one end negative electrode composite material 6b located inside the housing portion 4 (the negative electrode composite material 6 located at the lower end of the negative electrode composite material 6 housed inside the housing portion 4 in FIG. 3, 3 is provided with a first pressing portion 30 that applies a load F toward the pair of rolls 1 and 2 (from the upper side to the lower side). Furthermore, the other end negative electrode mixture 6c located inside the housing portion 4 (the negative electrode mixture 6 located at the upper end of the negative electrode mixture 6 housed inside the housing portion 4 in FIG. 3, in FIG. A second pressing portion 40 that applies a load F toward the pair of rolls 1 and 2 (from the upper side to the lower side) is provided for the portion indicated by the broken line.

  The first pressing part 30 has a rectangular flat plate-shaped pressing member 31 that contacts the one end negative electrode mixture 6b and presses it downward, and a cylindrical connecting part 32 that connects to the pressing member 31 and extends upward. Have An upper end portion (not shown) of the connection portion 32 is connected to an actuator (not shown). By driving the actuator, the first pressing portion 30 can move in the vertical direction, and a desired (arbitrarily set) load F can be applied to the one-end negative electrode mixture 6b (load F). Can be set arbitrarily).

  The second pressing portion 40 is a rectangular flat plate-shaped pressing member 41 that contacts and presses the other end negative electrode mixture 6c downward, and a columnar connecting portion 42 that is connected to the pressing member 41 and extends upward. Have An upper end portion (not shown) of the connection portion 42 is connected to an actuator (not shown). By driving the actuator, the second pressing portion 40 is movable in the vertical direction, and a desired (arbitrarily set) load F can be applied to the other end negative electrode mixture 6c (load F). Can be set arbitrarily).

  In the roll film forming apparatus 20 of this embodiment, the negative electrode mixture 6 (coating material) accommodated in the accommodating portion 4 is continuously in the gap between the facing portions of the first roll 1 and the second roll 2. The negative electrode mixture 6 (coating material) is continuously charged (supplied) into the accommodating portion 4 in accordance with the supply speed supplied to the container. As a result, the amount of the negative electrode mixture 6 in the housing portion 4 is kept substantially constant, and the first and second pressing portions 30 and 40 allow the negative electrode composites 6b and 6c (one end negative electrode compound) A substantially constant load F (set load) can be applied to the material 6b and the other end negative electrode mixture 6c).

  In such a roll film forming apparatus 20, the first pressing portion 30 and the second pressing portion 40 are directed toward the pair of rolls 1 and 2 with respect to the negative electrode composites 6 b and 6 c (both end coating materials). By applying a load F (from the top to the bottom), the porosity of both end negative electrode composites 6b and 6c (both end coating materials) is reduced, and both end negative electrodes accommodated in the accommodating portion 4 The gaps in the composite materials 6b and 6c can be reduced (reduced).

  Thereby, the space | gap 10A in the both-ends negative electrode compound materials 6b and 6c (both-ends coating material) supplied to the clearance gap between a pair of rolls 1 and 2 can be made small, The size of the gap 10A that interrupts the supply (the width dimension of the gap) can be reduced. Thereby, in the negative electrode mixture 6 (film-like negative electrode mixture 8) formed into a film by passing through the gap between the pair of rolls 1 and 2, the widthwise dimension (B) of the void portion 10B where the negative electrode mixture 6 does not exist ( The width direction dimension of the recess G in the width direction DW can be reduced. Therefore, the negative electrode mixture 6 (film negative electrode mixture 8) formed into a film by passing through the gap between the pair of rolls 1 and 2 has unevenness in the width direction DW at both ends 8b and 8c in the width direction DW. The degree (maximum unevenness dimension D) can be reduced.

Next, the manufacturing method of the negative electrode sheet 19 (electrode sheet, coated material) according to the present embodiment will be described.
First, in step S1 (electrode mixture preparation process), a negative active material (carbon material), a binder (CMC), and a solvent (water) are mixed and granulated to produce a large number of wet granules 16. At the same time, the negative electrode mixture 6 composed of a large number of wet granules 16 is produced. In the present embodiment, the negative electrode active material, the binder and the solvent are mixed (dispersed) in a known agitation granulator (not shown) by introducing the negative electrode active material, the binder and the solvent and stirring them. While granulating, a large number of wet granules 16 are formed. As a result, the negative electrode mixture 6 composed of a large number of wet granules 16 is obtained. The negative electrode mixture 6 is an aggregate of wet granulated bodies 16. In the present embodiment, the solid content of the negative electrode mixture 6 is set to 65 wt% or more (specifically, 71 wt%).

  Next, the process proceeds to step S2 (film formation process), and the negative electrode mixture 6 produced in step S1 is passed through a gap between opposing rolls (first roll 1 and second roll 2) to form a film. The negative electrode composite material 6 made to adhere is adhered on the surface of the current collector foil 7 (see FIGS. 1 to 3).

  Specifically, first, a predetermined amount of the negative electrode mixture 6 produced in step S <b> 1 is put into the accommodation space of the accommodation unit 4 of the roll film forming apparatus 20. Next, the first pressing portion 30 and the second pressing portion 40 are driven by actuators (not shown) to move the first pressing portion 30 and the second pressing portion 40 downward from above, so that both end negative electrode composites 6b, 6c ( A predetermined value (set from the top to the bottom) toward the pair of rolls 1 and 2 with respect to the negative electrode mixture 6 located at both ends in the width direction DW of the negative electrode mixture 6 in the housing portion 4. Value) load F. As a result, both end negative electrode composites 6b and 6c (both end coating materials) are compressed to reduce the porosity of both end negative electrode composites 6b and 6c, and the both end negative electrodes accommodated in the accommodating portion 4 The gaps in the composite materials 6b and 6c are reduced (reduced).

  Next, the first roll 1, the second roll 2, and the third roll 3 of the roll film forming apparatus 20 are driven to rotate. A current collector foil 7 is stretched over the third roll 3. Then, the negative electrode mixture 6 in the housing part 4 is regulated in width dimension E (dimension in the width direction DW) by the first side wall part 4b and the second side wall part 4c (a pair of side wall parts) of the housing part 4, In the gap between the facing positions of the first roll 1 and the second roll 2 so as to be drawn into the gap between the first roll 1 and the second roll 2 by the rotation of the first roll 1 and the second roll 2 (a pair of rolls). To be supplied. And it passes through the gap | interval of the 1st roll 1 and the 2nd roll 2, and is made into a film form, and becomes the film-form negative electrode compound material 8 (film-form coating material) (refer FIGS. 1-3, FIG. 6).

  At this time, since the rotation speed of the second roll 2 is faster than that of the first roll 1, the wet granulated body 16 included in the negative electrode mixture 6 is more on the surface of the second roll 2 than the surface of the first roll 1. Since the liquid bridge area on the surface of the second roll 2 becomes larger than the surface of the first roll 1, it is supported on the surface of the second roll 2 (see FIG. 6).

  Further, in accordance with the supply speed at which the negative electrode mixture 6 (coating material) housed in the housing portion 4 is continuously fed into the gap between the facing portions of the first roll 1 and the second roll 2, The negative electrode mixture 6 (coating material) is continuously charged into the housing part 4. As a result, the amount of the negative electrode mixture 6 in the housing portion 4 is kept substantially constant, and the first and second pressing portions 30 and 40 allow the negative electrode composites 6b and 6c (one end negative electrode compound) A substantially constant load F (set load) can be continuously applied to the material 6b and the other end negative electrode mixture 6c).

  The film-like negative electrode mixture 6 (film-like negative electrode mixture 8) carried on the surface of the second roll 2 is conveyed along with the rotation of the second roll 2 (see FIGS. 1 and 2). Then, the current collector foil 7 and the film-like negative electrode mixture 8 meet at the facing portion between the second roll 2 and the third roll 3. Thereby, the film-like negative electrode mixture 8 is transferred (attached) from the second roll 2 onto the surface of the current collecting foil 7 rotating together with the third roll 3 having a higher moving speed. In this way, the film-like negative electrode mixture 8 (coating material made into a film) is applied onto the surface of the current collector foil 7 (object to be applied). Thereby, the current collector foil 9 with the film-like negative electrode mixture in which the film-like negative electrode mixture 8 is formed on the current collector foil 7 is obtained.

Then, it progresses to step S3 (electrode mixture layer formation process), and the current collection foil 9 with a film-like negative electrode mixture is dried (the film-like negative electrode mixture 8 is dried). As a result, the solvent (water) absorbed (retained) in the film-like negative electrode mixture 8 (wet granulated body 16) is removed (evaporated), and the film-like negative electrode mixture 8 becomes the negative electrode mixture layer 18. (Electrode mixture layer). Thereby, the negative electrode sheet 19 having the negative electrode mixture layer 18 on the surface of the current collector foil 7 is obtained.
The film-like negative electrode mixture 8 (negative electrode mixture layer 18) may be formed only on one side of the current collector foil 7, or may be formed on both sides.

  The produced negative electrode sheet 19 is then combined with a positive electrode sheet and a separator to form an electrode body. Subsequently, after attaching a terminal member to this electrode body, an electrode body and electrolyte solution are accommodated in a battery case. Thereby, a lithium ion secondary battery is completed.

(Examples 1-5)
In Examples 1 to 5, in step S2 (film formation step), the negative electrode composite material 8b having a predetermined length is formed by changing the pressing conditions for the negative electrode composite materials 6b and 6c at both ends in the housing portion 4. A current collector foil 9 with a film-like negative electrode mixture having a predetermined length was produced. Specifically, in Examples 1 to 5, the width dimension J of the pressing member 31 of the first pressing part 30 (the dimension in the width direction DW, see FIG. 3) and the width dimension J of the pressing member 41 of the second pressing part 40. The load F is applied to the negative electrode composite materials 6b and 6c at both ends in the housing portion 4 in a different manner. In Examples 1 to 5, the load F (set load) applied to the negative electrode composites 6b and 6c by the first pressing portion 30 and the second pressing portion 40 is equal. The width dimension J and the load F of the pressing members 31 and 41 in Examples 1 to 5 are as shown in Table 1.

  In addition, as for the press members 31 and 41 of Examples 1-5, as for all, the edge part concerning the width direction DW is made into the position which adjoins to a pair of side wall part 4b, 4c of the accommodating part 4. FIG. That is, when the width dimension J of the pressing members 31 and 41 is increased, the pressing members 31 and 41 are enlarged to the center side in the width direction DW of the housing portion 4.

In Example 1, the width dimension J of the pressing members 31 and 41 was 5 mm. Further, the load F (set load) applied to the negative electrode composites 6b, 6c by the pressing members 31, 41 (the first pressing portion 30 and the second pressing portion 40) was set to 2N.
In the second embodiment, the width dimension J of the pressing members 31 and 41 is 8 mm unlike the first embodiment. Also, the load F (set load) applied to the negative electrode composites 6b, 6c by the pressing members 31, 41 (the first pressing portion 30 and the second pressing portion 40) was set to 2N as in the first embodiment. .

In the third embodiment, unlike the first embodiment, the width dimension J of the pressing members 31 and 41 is 10 mm. Also, the load F (set load) applied to the negative electrode composites 6b, 6c by the pressing members 31, 41 (the first pressing portion 30 and the second pressing portion 40) was set to 2N as in the first embodiment. .
In the fourth embodiment, the width dimension J of the pressing members 31 and 41 is 15 mm unlike the first embodiment. Also, the load F (set load) applied to the negative electrode composites 6b, 6c by the pressing members 31, 41 (the first pressing portion 30 and the second pressing portion 40) was set to 2N as in the first embodiment. .
In the fifth embodiment, the width dimension J of the pressing members 31 and 41 is 20 mm unlike the first embodiment. Also, the load F (set load) applied to the negative electrode composites 6b, 6c by the pressing members 31, 41 (the first pressing portion 30 and the second pressing portion 40) was set to 2N as in the first embodiment. .

(Examples 6 to 13)
Also in Examples 6 to 13, in step S2 (film formation step), the negative electrode composite material 8 having a predetermined length is formed by changing the pressing conditions for the negative electrode composite materials 6b and 6c at both ends in the housing portion 4. A current collector foil 9 with a film-like negative electrode mixture having a predetermined length was produced. Specifically, in Examples 6 to 13, the first pressing part 30 and the second pressing part 40 differ in the load F (set load) applied to the both-end negative electrode composites 6b and 6c. In Examples 6 to 13, the width dimension J of the pressing members 31 and 41 is the same. The width dimension J and the load F of the pressing members 31 and 41 in Examples 6 to 13 are as shown in Table 1.

In Example 6, the width dimension J of the pressing members 31 and 41 was 20 mm. Further, the load F (set load) applied to the negative electrode composite materials 6b, 6c by the pressing members 31, 41 (the first pressing portion 30 and the second pressing portion 40) was set to 5N.
In Example 7, the width dimension J of the pressing members 31 and 41 was set to 20 mm as in Example 6. Also, the load F (set load) applied to the negative electrode composites 6b, 6c by the pressing members 31, 41 (the first pressing portion 30 and the second pressing portion 40) is set to 6N, unlike the sixth embodiment. .

In Example 8, the width dimension J of the pressing members 31 and 41 was set to 20 mm as in Example 6. Also, the load F (set load) applied to the negative electrode composites 6b, 6c by the pressing members 31, 41 (the first pressing portion 30 and the second pressing portion 40) is set to 7N, unlike the sixth embodiment. .
In Example 9, the width dimension J of the pressing members 31 and 41 was set to 20 mm as in Example 6. Also, the load F (set load) applied to the negative electrode composites 6b, 6c by the pressing members 31, 41 (the first pressing portion 30 and the second pressing portion 40) is set to 8N, unlike the sixth embodiment. .

In Example 10, the width dimension J of the pressing members 31 and 41 was set to 20 mm as in Example 6. Also, the load F (set load) applied to the negative electrode composites 6b, 6c by the pressing members 31, 41 (the first pressing portion 30 and the second pressing portion 40) is 9N, unlike the sixth embodiment. .
In Example 11, the width dimension J of the pressing members 31 and 41 was set to 20 mm as in Example 6. Also, unlike the example 6, the load F (set load) applied to the negative electrode composites 6b, 6c by the pressing members 31, 41 (the first pressing part 30 and the second pressing part 40) was set to 10N. .

In Example 12, the width dimension J of the pressing members 31 and 41 was set to 20 mm as in Example 6. Further, the load F (set load) applied to the negative electrode composites 6b, 6c by the pressing members 31, 41 (the first pressing portion 30 and the second pressing portion 40) is set to 12N, unlike the sixth embodiment. .
In Example 13, the width dimension J of the pressing members 31 and 41 was set to 20 mm as in Example 6. Also, the load F (set load) applied to the negative electrode composites 6b, 6c by the pressing members 31, 41 (the first pressing portion 30 and the second pressing portion 40) is set to 14N, unlike the sixth embodiment. .

(Comparative Example 1)
In Comparative Example 1, unlike Examples 1 to 13 (similar to the prior art), in Step S2 (film formation step), no load is applied to the negative electrode composites 6b and 6c at both ends in the housing portion 4. The film-like negative electrode mixture 8 having a predetermined length is formed (without using the first pressing part 30 and the second pressing part 40), and the current-collecting foil 9 with the film-like negative electrode mixture having a predetermined length is formed. Was made.

(Evaluation of membrane negative electrode composite)
About the film-like negative electrode composite material 8 of Examples 1 to 13 and Comparative Example 1 produced as described above, the maximum unevenness dimension D (see FIGS. 7 and 8) was investigated. In addition, the uneven | corrugated largest dimension D is the maximum value of the distance concerning the width direction DW between the recessed part G and the convex part H in the film-form negative electrode compound material 8 of predetermined length (refer FIG.7 and FIG.8). The results are shown in Table 1.

  As shown in Table 1, in Comparative Example 1, the maximum unevenness dimension D was 5.0 mm. On the other hand, in Examples 1-13, the uneven | corrugated maximum dimension D became 3.0 mm or less, and compared with the comparative example 1, the uneven | corrugated maximum dimension D was able to be made small enough.

  From the above results, the first pressing portion 30 and the second pressing portion 40 make a pair of rolls 1 and 2 in the negative electrode composites 6b and 6c (both ends coating material) accommodated in the accommodating portion 4. By applying a load F toward the second side (from the top to the bottom), the degree of unevenness in the width direction (film-like negative electrode composite) at both ends in the width direction of the film-like negative electrode mixture 8 (film-form coating material) It can be said that the maximum unevenness dimension D) of the material 8 can be reduced.

  By the first pressing portion 30 and the second pressing portion 40, toward the pair of rolls 1, 2 toward the inside of the negative electrode composites 6 b, 6 c at both ends housed in the housing portion 4 (from above to below) The load F is applied to greatly reduce the porosity of both end negative electrode composites 6b and 6c (both end coating materials), and both end negative mixes 6b and 6c accommodated in the accommodating portion 4 are applied. It is considered that the internal voids could be reduced (reduced). Thereby, the space | gap 10A in the both-ends negative electrode compound materials 6b and 6c (both-ends coating material) supplied to the clearance gap between a pair of rolls 1 and 2 can be made small, It is considered that the size of the gap 10A that interrupts the supply (the width dimension of the gap) could be reduced.

  Thereby, in the negative electrode mixture 6 (film-like negative electrode mixture 8) formed into a film by passing through the gap between the pair of rolls 1 and 2, the widthwise dimension (B) of the void portion 10B where the negative electrode mixture 6 does not exist ( The width-direction dimension of the concave portion G in the width direction DW can be reduced, and the degree of unevenness in the width direction DW at the both end portions 8b, 8c in the width direction DW (maximum unevenness dimension D) of the film-like negative electrode composite 8 It is thought that it was possible to make it smaller.

(Examination of width of pressing member)
As described above, the concavo-convex maximum dimension D (see Table 1) was examined for the film-like negative electrode mixture 8 of Examples 1 to 5 manufactured using the pressing members 31 and 41 having different width dimensions J. Moreover, based on the result of Examples 1-5, the correlation diagram of the width dimension J of an pressing member and the uneven | corrugated largest dimension D was produced. This correlation diagram is shown in FIG.

  As shown in Table 1, in Example 1 in which the width dimension J of the pressing members 31 and 41 was 5 mm, the maximum unevenness dimension was 3.0 mm. In Example 2 in which the width dimension J of the pressing members 31 and 41 was 8 mm, the maximum unevenness dimension was 2.0 mm. Further, in Example 3 in which the width dimension J of the pressing members 31 and 41 was 10 mm, the maximum unevenness dimension was 1.4 mm. In Example 4 in which the width dimension J of the pressing members 31 and 41 was 15 mm, the maximum unevenness dimension was 0.9 mm. In Example 5 in which the width dimension J of the pressing members 31 and 41 was 20 mm, the maximum unevenness dimension was 0.8 mm.

  Further, as shown in FIG. 4, as the width dimension J of the pressing members 31 and 41 is increased, the maximum unevenness dimension is reduced, and by setting the width dimension J of the pressing members 31 and 41 to 15 mm or more, The maximum unevenness dimension could be reduced to 1.0 mm or less.

  From these results, by setting the width dimension J of the pressing members 31 and 41 to 15 mm or more, the porosity of the both-end negative electrode composites 6b and 6c (both-end coating material) is greatly reduced, and the inside of the accommodating portion 4 is reduced. It is considered that the voids in the negative electrode composites 6b and 6c accommodated at both ends could be made extremely small (reduced). As a result, the gap 10A in the negative electrode composites 6b and 6c (both end coating materials) supplied to the gap between the pair of rolls 1 and 2 can be made extremely small. It is considered that the size of the gap 10A (the width dimension of the gap) that interrupts the supply of the gas can be made extremely small.

  Thereby, in the negative electrode mixture 6 (film-like negative electrode mixture 8) formed into a film by passing through the gap between the pair of rolls 1 and 2, the widthwise dimension (B) of the void portion 10B where the negative electrode mixture 6 does not exist ( The width-direction dimension of the recess G in the width direction DW can be made extremely small, and the degree of unevenness in the width direction DW at the both end portions 8b, 8c in the width direction DW (the maximum unevenness dimension D) is obtained. ) Can be reduced.

  From the above, it can be said that the width dimension J of the pressing members 31 and 41 is preferably 15 mm or more. That is, with respect to the negative electrode mixture 6 (coating material) accommodated in the accommodating portion 4, the load is applied toward the pair of rolls 1, 2 (downward) from the pair of side wall portions 4b, 4c over a width dimension of 15 mm or more. It can be said that it is preferable to add.

(Examination of load by pressing part)
As described above, the uneven maximum dimension D (see Table 1) is examined for the film-like negative electrode mixture 8 of Examples 5 to 13 manufactured by varying the load F by the first pressing portion 30 and the second pressing portion 40. did. Moreover, based on the result of Examples 5-13, the correlation diagram of the load F and the uneven | corrugated largest dimension D was produced. This correlation diagram is shown in FIG.

  As shown in Table 1, in Example 5 where the load F was 2N, the maximum unevenness dimension D was 0.8 mm. In Example 6 in which the load F was 5 N, the maximum unevenness dimension D was 0.6 mm. In Example 7 in which the load F was 6N, the maximum unevenness dimension D was 0.5 mm. In Example 8 in which the load F was 7 N, the maximum unevenness dimension D was 0.4 mm. In Example 9 in which the load F was 8 N, the maximum unevenness dimension D was 0.6 mm. In Example 10 in which the load F was 9 N, the maximum unevenness dimension D was 0.8 mm. In Example 11 in which the load F was 10 N, the maximum unevenness dimension D was 0.9 mm. In Example 12 in which the load F was 12 N, the maximum unevenness dimension D was 1.2 mm. In Example 13 in which the load F was 14N, the maximum unevenness dimension D was 1.5 mm.

  Further, as shown in FIG. 5, as the load F is increased from 2N, the maximum unevenness dimension D decreases, and when the load F is 7N, the maximum unevenness dimension D can be minimized. It was. As the load F is increased from 7N, the maximum unevenness dimension D increases. However, in the range where the load F is 10N or less, the maximum unevenness dimension D can be reduced to 0.9 mm or less. On the other hand, when the load F was 12 N or more, the maximum unevenness dimension D was 1.2 mm or more.

  From these results, it is considered that by increasing the load F, it is possible to reduce (reduce) the gaps in the both-end negative electrode composites 6b and 6c accommodated in the accommodating portion 4. However, if the load F is excessively increased (specifically, 12N or more), the wet granulated body 16 included in the negative electrode composite materials 6b and 6c at both ends is crushed, and the maximum unevenness dimension D is caused by the influence. Is considered to be as large as 1.2 mm or more.

  From the above, it can be said that the load F is preferably set to a value in the range of 2N to 10N. That is, of the negative electrode mixture 6 (coating material) housed in the housing part 4, both end negative electrode composites 6 b and 6 c (both end part coating material) positioned at both ends in the housing part 4 in the width direction DW. On the other hand, it can be said that the magnitude of the load F applied toward the pair of rolls 1 and 2 is preferably set to a value in the range of 2N to 10N.

In the above, the present invention has been described with reference to the embodiments (Examples 1 to 13). However, the present invention is not limited to the above-described embodiments, and can be appropriately modified and applied without departing from the gist thereof. Needless to say, it can be done.
For example, in the embodiment, an example in which the roll film forming apparatus is used for manufacturing a negative electrode sheet of a battery is shown. However, you may make it use the roll film-forming apparatus of this invention for manufacture of the positive electrode sheet of a battery.

1 First roll (a pair of rolls)
2 Second roll (a pair of rolls)
3 3rd roll 4 accommodating part 4b 1st side wall part (a pair of side wall part)
4c 2nd side wall part (a pair of side wall part)
6 Negative electrode mixture (coating material)
6b One end negative electrode mixture (both ends negative electrode mixture, both ends coating material)
6c Negative electrode mixture at the other end (negative electrode mixture at both ends, coating material at both ends)
7 Current collector foil (Subject to be coated)
8 Film-like negative electrode mixture (coating material made into a film)
16 Wet granulated body 18 Negative electrode composite material layer (electrode composite material layer)
19 Negative electrode sheet (electrode sheet)
20 roll film forming apparatus 30 first pressing part 31 pressing member 40 second pressing part 41 pressing member D unevenness maximum dimension G recessed part H protruding part DW width direction E width dimension F load

Claims (1)

A pair of rolls arranged in parallel to each other with a gap and rotating;
An accommodation portion that is disposed immediately above the pair of rolls and accommodates a coating material composed of a plurality of wet granulation bodies,
The accommodating portion is a pair of side wall portions that are spaced apart in the width direction of the roll, and a pair of side walls that regulate the width direction dimension of the coating material supplied to the gap between the pair of rolls Part
While the width of the coating material accommodated in the accommodating portion is regulated by the pair of side wall portions, the coating material is drawn into the gap between the pair of rolls by the rotation of the pair of rolls. A roll film forming apparatus in which the coating material formed into a film by being supplied to the gap and passing through the gap between the pair of rolls is coated on the surface of the object to be coated,
Of the coating material accommodated in the accommodating portion, a pressing portion is provided that applies a load toward the pair of rolls with respect to both end portion coating materials positioned at both end portions in the accommodating portion in the width direction. Roll film forming equipment.

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