APPARATUS FOR MANUFACTURING ELECTRODE ACTIVE MATERIAL LAYER

A production apparatus of an electrode active material layer, comprising: a support unit; a feeding unit feeding prescribed granulated particles on or above the support unit; a first conveying unit; a squeegee unit; a first stock guide; a second stock guide; a first position measurement unit; a second position measurement unit; a rolling unit; a first gap adjustment unit; a second gap adjustment unit; and a control unit. The first position measurement unit measures a distance D1. The second position measurement unit measures a distance D2. The control unit causes the first gap adjustment unit to adjust a gap G1 based on a difference between the gap G1 obtained based on the distance D1 and a gap threshold T1 and causes the second gap adjustment unit to adjust a gap G2 based on a difference between the gap G2 obtained based on the distance D2 and a gap threshold T2.

TECHNICAL FIELD

The present invention relates to a production apparatus of an electrode active material layer.

BACKGROUND ART

Electrode sheets, which are components of batteries such as a lithium ion rechargeable battery, can include an electrode active material layer. The electrode active material layer is usually formed on a substrate that is a current collector. As an apparatus for forming an electrode active material layer, an apparatus that deposits granulated particles containing an electrode active material as a layer on a substrate and rolls the layer of the granulated particles has been known. To uniformize the thickness of the granulated particle layer, the production apparatus of an electrode active material layer includes a member (squeegee unit) that levels the granulated particles deposited on the widthwise midsection of the granulated particle layer and guides the granulated particles to both widthwise end portions. Techniques for reducing the conveyance of the granulated particles guided to both widthwise end portions beyond the specified width of the granulated particle layer downstream in the conveyance direction of the granulated particle layer have been known (see Patent Literatures 1 to 4).

CITATION LIST

Patent Literature

SUMMARY OF THE INVENTION

Technical Problem

The granulated particles that are leveled and guided to both widthwise end portions of the granulated particle layer by the squeegee unit may possibly go beyond both widthwise end portions of the squeegee unit and may be conveyed downstream depending on the production conditions, such as when the amount of granulated particles fed is excessive. The excess granulated particles that have been conveyed downstream can get into a rolling unit such as a rolling roll and cause defective formation of the electrode active material layer.

To remove the excess granulated particles that have been conveyed downstream, a production apparatus of Patent Literature 1 includes jigs and a dust suction device for removing both end portions of the granulated particle layer formed beyond a specified width. A production apparatus of Patent Literature 2 includes an air purge device for removing both end portions of the granulated particle layer by blowing gas.

However, the production apparatus of Patent Literature 1 and the production apparatus of Patent Literature 2 may have difficulty in stably producing an electrode active material layer because of excess granulated particles conveyed downstream beyond both widthwise end portions of the squeegee unit. In addition, the occurrence of excess granulated particles increases production costs.

Production apparatuses of Patent Literatures 3 and 4 include guide members for forming areas where granulated particles are not deposited. However, such guide members physically contact the surface where the granulated particles are deposited. If, for example, the granulated particles are deposited on the substrate, and the relative positions of the substrate and the guide members in the width direction vary due to factors such as tension fluctuations during substrate conveyance, the substrate can therefore be distorted and break. If, for example, the granulated particles are directly deposited on a support unit such as a roll, the guide members wear due to the contact of the support unit and the guide members. In such a case, the guide units can fail to serve their function because of the increased gaps between the substrate area and the guide units.

As a result, it has sometimes been difficult to stably produce the electrode active material layer.

A production apparatus capable of stably producing an electrode active material layer is thus desired.

Solution to Problem

The inventor has made an intensive study to solve the foregoing problem, and as a result found that the problem can be solved by a production apparatus including certain stock guides and a certain control unit, and completed the present invention.

More specifically, the present invention provides the following.

<1> A production apparatus of an electrode active material layer, comprising:a support unit;a feeding unit that feeds granulated particles on or above the support unit, the granulated particles containing an electrode active material and a binder;a first conveying unit that conveys the granulated particles that have been fed on or above the support unit;a squeegee unit that levels the granulated particles which are conveyed to form a granulated particle layer;a first stock guide having a plate shape, the first stock guide having a first surface facing the support unit, the first stock guide being disposed in parallel with a first end face of the squeegee unit;a second stock guide having a plate shape, the second stock guide having a second surface facing the support unit, the second stock guide being disposed in parallel with a second end face of the squeegee unit; anda rolling unit that rolls the granulated particle layer to form an electrode active material layer,wherein:the production apparatus further comprises a first position measurement unit fixed to the first stock guide, a second position measurement unit fixed to the second stock guide, a first gap amount adjustment unit, a second gap amount adjustment unit, and a control unit;the first stock guide and the second stock guide are disposed so that a distance between a main surface of the first stock guide and a main surface of the second stock guide is equivalent to a width of the electrode active material layer;the first position measurement unit is capable of measuring a distance D1between the first position measurement unit and a surface that faces the first surface of the first stock guide and to which the granulated particles are fed;the second position measurement unit is capable of measuring a distance D2between the second position measurement unit and a surface that faces the second surface of the second stock guide and to which the granulated particles are fed;the first gap amount adjustment unit is capable of adjusting a gap amount G1between the first surface of the first stock guide and the surface to which the granulated particles are fed;the second gap amount adjustment unit is capable of adjusting a gap amount G2between the second surface of the second stock guide and the surface to which the granulated particles are fed;the control unit causes the first gap amount adjustment unit to adjust the gap amount G1based on a difference between the gap amount G1obtained based on the distance D1and a gap amount threshold T1that has been set to be greater than 0 μm; andthe control unit causes the second gap amount adjustment unit to adjust the gap amount G2based on a difference between the gap amount G2obtained based on the distance D2and a gap amount threshold T2that has been set to be greater than 0 μm.

<2> The production apparatus of an electrode active material layer according to <1>, wherein:the first position measurement unit is fixed to a first end face of the first stock guide opposite to the first surface of the first stock guide;the first stock guide has a first through-hole that runs through from the first end face of the first stock guide, to which the first position measurement unit is fixed, to the first surface;the first position measurement unit is configured to be capable of measuring the distance D1through the first through-hole;the second position measurement unit is fixed to a second end face of the second stock guide opposite to the second surface of the second stock guide;the second stock guide has a second through-hole that runs through from the second end face of the second stock guide, to which the second position measurement unit is fixed, to the second surface; andthe second position measurement unit is configured to be capable of measuring the distance D2through the second through-hole.

<3> The production apparatus of an electrode active material layer according to <1> or <2>, further comprising a second conveying unit that conveys a substrate to the rolling unit, wherein the rolling unit rolls the granulated particle layer that has been overlaid on the conveyed substrate.

<4> The production apparatus of an electrode active material layer according to <1> or <2>, further comprising a third conveying unit that conveys a substrate to the support unit, wherein:the support unit supports the substrate;the feeding unit feeds the granulated particles on the substrate that has been supported by the support unit;the first position measurement unit is configured to be capable of measuring the distance D1between the first position measurement unit and a main surface of the substrate that faces the first surface of the first stock guide;the second position measurement unit is configured to be capable of measuring the distance D2between the second position measurement unit and a main surface of the substrate that faces the second surface of the second stock guide;the control unit obtains the gap amount G1based on the distance D1and causes the first gap amount adjustment unit to adjust the gap amount G1based on a difference between the gap amount G1and the gap amount threshold T1that has been set so that a distance between the first surface of the first stock guide and the main surface of the substrate becomes greater than 0 μm; andthe control unit obtains the gap amount G2based on the distance D2and causes the second gap amount adjustment unit to adjust the gap amount G2based on a difference between the gap amount G2and the gap amount threshold T2that has been set so that a distance between the second surface of the second stock guide and the main surface of the substrate becomes greater than 0 μm.

<5> The production apparatus of an electrode active material layer according to any one of <1> to <4>, wherein a single roll serves as the support unit and the first conveying unit.

<6> The production apparatus of an electrode active material layer according to any one of <1> to <5>, wherein:the support unit is a rotatable roll;the control unit acquires a data set A1on the distance D1during a period in which the support unit rotates two revolutions or more, analyzes the data set A1, predicts the distance D1, which varies depending on the rotation of the support unit, and causes the first gap amount adjustment unit to adjust the gap amount G1based on the predicted distance D1; andthe control unit acquires a data set A2on the distance D2during a period in which the support unit rotates two revolutions or more, analyzes the data set A2, predicts the distance D2, which varies depending on the rotation of the support unit, and causes the second gap amount adjustment unit to adjust the gap amount G2based on the predicted distance D2.

Advantageous Effects of Invention

According to the present invention, a production apparatus of an electrode active material layer capable of stably producing an electrode active material layer can be provided.

DESCRIPTION OF EMBODIMENTS

Hereinafter, the present invention will be described in detail with reference to embodiments and examples. However, the present invention is not limited to embodiments and examples described below, and may be freely modified for implementation without departing from the scope of claims of the present invention and the scope of their equivalents. Components of embodiments described below may be combined as appropriate. In the drawings, the same components are denoted by the same reference numerals, and descriptions thereof may be omitted.

In the following description, a “long-length” film refers to a film with the length that is 5 times or more the width of the film, and preferably a film with the length that is 10 times or more the width thereof, and specifically refers to a film having a length that allows a film to be wound up into a rolled shape for storage or transportation. The upper limit of the length of a film relative to the width of the film may be, but not particularly limited to, for example, 100,000 times or less the width.

In the following description, a direction of an element being “parallel”, “perpendicular” or “orthogonal” may allow an error within the range of not impairing the advantageous effects of the present invention, for example, within a range of +3°, +2°, or +1° unless otherwise specified.

In the following description, “on” or “above” an element covers a case where a direct contact is made with the element and a case where an indirect contact is made with the element.

An electrode active material layer produced by a production apparatus that is an embodiment of the present invention is obtained by rolling a layer of granulated particles. The electrode active material layer is preferably formed on a substrate. The substrate is preferably a long-length one.

Examples of the substrate may include: metal foils formed of aluminum, platinum, nickel, tantalum, titanium, stainless steel, copper, and other alloys; films containing electroconductive materials (such as carbon and electroconductive macromolecular materials); paper; fabric cloths formed of natural fibers, synthetic fibers, and the like; and resin films containing polymers. Examples of the polymers that can be contained in the resin films may include: a polyester such as polyethylene terephthalate and polyethylene naphthalate; a polyimide; a polypropylene; a polyphenylene sulfide; a polyvinyl chloride; an aramid; PEN; and PEEK. Such materials can be selected as appropriate depending on the intended purposes.

Among these, the preferable substrate may be a metal foil, a film containing a carbon material, and a film containing an electroconductive macromolecular material, more preferably a metal foil, and still more preferably a copper foil, an aluminum foil, and an aluminum alloy foil from the viewpoint of electroconductivity and withstand voltage. Such substrates are suitable for the production of electrode sheets for lithium ion batteries.

The substrate may be subjected to a surface treatment such as a coating film treatment, a punching process, a buffing process, a sand blasting process, or an etching process, or may be subjected to multiple surface treatments.

The thickness of the substrate is not particularly limited. The thickness is preferably 1 μm or more, and more preferably 5 μm or more, and is preferably 1000 μm or less, and more preferably 800 μm or less. The substrate may have any given width.

The granulated particles usually contain the electrode active material and a binder, and, as necessary, may contain optional components such as a dispersant, an electroconductive material, and an additive.

The electrode active material contained in the granulated particles may be a positive electrode active material or a negative electrode active material. Examples of the positive electrode active material and the negative electrode active material may include materials that can be used as an electrode active material for lithium ion batteries. Examples of the positive electrode active material may include a metal oxide that can be reversibly doped and undoped with lithium ions. Examples of such metal oxides may include lithium cobalt oxide (LiCoO2), lithium nickel oxide (LiNiO), lithium manganese oxide (LiMn2O4), lithium iron phosphate (LiFePO4), and ternary active materials obtained by substituting nickel and manganese for a part of lithium cobalt oxide (for example, LiCo1/3Ni1/3Mn1/3O2). As the positive electrode active material, one type thereof may be solely used, and two or more types thereof may also be used in combination.

Examples of the negative electrode active material may include: low crystallizable carbons (amorphous carbons) (e.g., easily graphitizable carbon, non-graphitizable carbon, and pyrolytic carbon); graphite (e.g., natural graphite and synthetic graphite); alloy-based materials containing tin, silicon, and the like; and oxides (e.g., silicon oxide, tin oxide, and lithium titanate). As the negative electrode active material, one type thereof may be solely used, and two or more types thereof may also be used in combination.

The electrode active material is preferably in a granular form. With the granular particle form, the electrode active material can be shaped into a high-density electrode.

The volume-average particle diameter (D50) of the electrode active material is preferably 0.1 μm or more and 100 μm or less, more preferably 0.3 μm or more and 50 μm or less, and still more preferably 0.5 μm or more and 30 μm or less. When the volume-average particle diameter (D50) of the electrode active material falls within the above-described range, the electrode active material can be suitably used as a material for a lithium ion battery electrode.

The binder contained in the granulated particles is preferably a compound capable of binding the electrode active materials to each other. The binder is more preferably a dispersive binder having a property of dispersing when in a solvent. Examples of the dispersive binder may include macromolecular compounds such as a silicon atom-containing polymer, a fluorine atom-containing polymer, a conjugated diene-based polymer, an acrylate-based polymer, a polyimide, a polyamide, and a polyurethane.

The shape of the dispersive binder is not particularly limited, and preferably particulate. A particulate dispersive binder can improve the binding property and can reduce a drop in the capacity of the produced electrode and the deterioration of the produced electrode due to repetitive charging and discharging. Examples of the particulate binder may include an aqueous dispersion of binder particles such as latex, and a particulate binder obtained by drying such an aqueous dispersion.

The amount of the binder, based on dry weight, is preferably 0.1 part by weight or more and 50 parts by weight or less, more preferably 0.5 part by weight or more and 20 parts by weight or less, and still more preferably 1 part by weight or more and 15 parts by weight or less, relative to 100 parts by weight of the electrode active material, from the viewpoint of sufficiently ensuring adhesion between the obtained electrode active material layer and the substrate and reducing the internal resistance.

The granulated particles may contain a dispersant as an optical component. Examples of the dispersant may include cellulosic polymers such as carboxymethylcellulose and methylcellulose, and ammonium or alkali metal salts thereof. As these dispersants, one type thereof may be solely used, and two or more types thereof may also be used in combination.

The granulated particles may contain an electroconductive material as an optional component. Examples of the electroconductive material may include electroconductive carbon blacks such as furnace black, acetylene black, and Ketjen black (registered trademark of Akzo Nobel Chemicals B.V.). Acetylene black and Ketjen black are preferable. Vapor-grown carbon fibers such as VGCF (registered trademark) and carbon nanotubes; graphite-based carbon materials such as expanded graphite and graphite; and graphene can also be used as the electroconductive material. As these electroconductive materials, one type thereof may be solely used, and two or more types thereof may also be used in combination.

The granulated particles can be produced by granulating the electrode active material and the binder, and optional component(s) that may be included as needed. Examples of the method for producing the granulated particles may include, but are not limited to, known granulation methods such as a fluidized bed granulation method, a spray drying granulation method, and a tumbling bed granulation method.

Each of the granulated particles is preferably in the form of a secondary particle formed by aggregation of a plurality of primary particles.

Specifically, each of the granulated particles is preferably a secondary particle formed by binding a plurality (preferably, several to several tens) of electrode active materials and optional components with the binder.

The volume-average particle diameter (D50) of the granulated particles is preferably 0.1 μm or more, more preferably 1 μm or more, still more preferably 20 μm or more, and further more preferably 30 μm or more, and is preferably 1000 μm or less, more preferably 500 μm or less, and still more preferably 250 μm or less, from the viewpoint of easily obtaining an electrode active material layer having the desired thickness.

The volume-average particle diameter (D50) of the granulated particles is a 50% volume-average particle diameter measured in a dry manner and calculated using a laser scattering and diffraction-based particle size distribution measurement device (for example, Microtrac MT3300EX II; manufactured by MicrotracBEL Corp). The 50% volume-average particle diameter is the particle diameter at a point where the cumulative frequency accumulated from the smaller diameter side on the obtained particle size distribution (volume basis) reaches 50%.

The number-average particle diameter of the granulated particles to be described below is a particle diameter measured in a dry manner and calculated using a laser scattering and diffraction-based particle size distribution measurement device (for example, Microtrac MT3300EX II; manufactured by MicrotracBEL Corp). For example, a 50% number-average particle diameter (D50) is the particle diameter at a point where the cumulative frequency accumulated from the smaller diameter side on the obtained particle size distribution (number basis) reaches 50%.

1. First Embodiment

A production apparatus of an electrode active material layer according to a first embodiment will be described below with reference to the drawings.

FIG.1is a schematic diagram illustrating the production apparatus of an electrode active material layer according to the first embodiment.FIG.2is a top view schematically illustrating a part of the production apparatus according to the first embodiment.FIG.3is a side view schematically illustrating a part of the production apparatus according to the first embodiment.FIG.4is a schematic diagram illustrating a configuration of a control unit of the production apparatus according to the first embodiment.

As illustrated inFIG.1, a production apparatus100according to the present embodiment includes a forming roll101, a feeding unit103, a third conveying unit104, a squeegee roll105serving as a squeegee unit, a first stock guide110a, a second stock guide110b, a first position measurement unit120a, a second position measurement unit120b, a rolling roll130a, a first gap amount adjustment unit131a, a second gap amount adjustment unit131b, and a control unit140. The forming roll101functions as a support unit, as a first conveying unit, and with the rolling roll130a, as a rolling unit130.

In the present embodiment, the production apparatus100includes one squeegee roll and two stock guides. In another embodiment, a production apparatus may include two or more, n squeegee rolls and (n+1) stock guides. The n squeegee rolls and the (n+1) stock guides may be alternately disposed so that a stock guide is located at each end of a squeegee roll. An electrode active material layer of stripe shape can thereby be stably produced.

The forming roll101is a cylindrical member and is supported to be rotatable about an axis R101in a direction DR101. The third conveying unit104conveys a substrate1to the forming roll101serving as the support unit. The forming roll101conveys the substrate1downstream while rotating in the direction DR101. An example of the third conveying unit104is a conveying roll.

The feeding unit103feeds granulated particles P, onto a main surface of the substrate1supported by the forming roll101and above the forming roll101. An optional powder feeding device may be used as the feeding unit103. Examples of the powder feeding mechanism may include a pressure-feeding type, a rotary vane type, a screw type, and a rotary drum type.

The feeding unit103of the present embodiment includes a hopper unit having a granulated particle inlet and a granulated particle outlet. The granulated particles P are loaded from the granulated particle inlet. The granulated particles P are fed through the granulated particle outlet onto the main surface of the substrate1supported by the forming roll101. That is, in the present embodiment, the surface to which the granulated particles P are fed is the main surface of the substrate1.

The forming roll101serving as the first conveying unit rotates in the direction DR101to thereby convey the granulated particles P, which have been fed onto the main surface of the substrate1, downstream together with the substrate1.

The squeegee roll105serving as the squeegee unit is a cylindrical member and supported to be rotatable about the axis R105in a direction DR105opposite to the direction DR101. A not-shown driving device is attached to the squeegee roll105, and rotates the squeegee roll105in the direction DR105.

The rotation of the squeegee roll105in the direction DR105opposite to the conveyance direction of the substrate1levels the granulated particles P fed onto and conveyed on the main surface of the substrate1supported by the forming roll101to a predetermined thickness, whereby a granulated particle layer2is formed.

The squeegee roll105is provided with a not-shown position adjustment mechanism so that the distance between the peripheral surface of the squeegee roll105and the peripheral surface of the forming roll101serving as the first conveying unit can be adjusted. The thickness of the granulated particle layer2can be adjusted by adjusting the distance. As a result, the weight per unit area (basis weight) of an electrode active material layer3obtained by rolling the granulated particle layer2can be adjusted.

As shown inFIG.2, the squeegee roll105has a first end face105E1and a second end face105E2perpendicular to the axis R105.

The first stock guide110ahaving a plate shape is disposed in parallel with the first end face105E1of the squeegee roll105. The second stock guide110bhaving a plate shape is disposed in parallel with the second end face105E2of the squeegee roll105.

A distance W110between the main surface of the first stock guide110aon the squeegee roll105side and the main surface of the second stock guide110bon the squeegee roll105side is equivalent to the width of the electrode active material layer3to be produced.

The material constituting the first stock guide110aand the second stock guide110bis not limited in particular. Examples of the material of the stock guide may include: resins such as poly(tetrafluoroethylene) (PTFE), poly(acrylonitrile butadiene styrene) (ABS), polypropylene (PP), polystyrene (PS), polyethylene (PE), ultra-high-molecular-weight polyethylene, monomer casting nylon (UMC), poly(vinyl chloride) (PVC), polyacetal, and a methacrylic resin; and metals such as aluminum and stainless steel. Since the coefficient of dynamic friction of the stock guides can be reduced, the material of the stock guide is preferably a resin, and more preferably a fluororesin such as PTFE.

The first stock guide110aand the second stock guide110bpreferably have low dynamic friction with the substrate1. Specifically, the first stock guide110aand the second stock guide110bpreferably have a coefficient of dynamic friction of 0.50 or lower, and more preferably 0.40 or lower. The coefficient of dynamic friction of the first stock guide110aand the second stock guide110bis ideally 0, and the lower limit can be 0.04 or higher. The coefficient of dynamic friction of the first stock guide110aand the second stock guide110bwith the substrate1can be measured in accordance with JIS K7125.

The lower the coefficient of dynamic friction of the stock guide is, the more the adhesion between the granulated particles and the stock guide is likely to decrease. As a result, the decrease in the smoothness of the end portion of the electrode active material layer due to the adhesion of the granulated particles to the stock guide can be suppressed.

In addition, the stock guide may be subjected to a surface treatment in order to reduce the coefficient of dynamic friction. Examples of such a surface treatment may include a fluororesin coating treatment, application of a lubricant, and a plating treatment.

The first stock guide110a, the second stock guide110b, and the squeegee roll105constitute a squeegee device, to respective end portions of which fixing members for restricting the movement of the first stock guide110aand the second stock guide110bin the axial direction of the rotation shaft may be attached. For example, the fixing members may include a fixing plate fixed to the rotation shaft and an elastic member including an elastic body such as a coil spring, a leaf spring, and a rubber plate. Specifically, the fixing members may be configured so that the elastic members press the first stock guide110aand the second stock guide110bdisposed at both end portions of the squeegee roll105toward the center of the squeegee roll105in the axial direction, whereby the first stock guide110aand the second stock guide110bare fixed to not move in the axial direction of the rotation shaft. Such a configuration of the fixing members makes the first stock guide110aand the second stock guide110bfreely rotatable about the rotation shaft. Since the fixing members fix the first stock guide110aand the second stock guide110bso that the first stock guide110aand the second stock guide110bcan rotate freely about the rotation shaft and do not move in the axial direction of the rotation shaft, the positions of both the first stock guide110aand the second stock guide110bin the lengthwise direction of the squeegee device are less likely to vary due to vibrations during production, or the like. This suppresses a change in the distance between the main surfaces of the first stock guide110aand the second stock guide110b, and the electrode active material layer3with a predetermined width can be stably produced.

The fixing members may be configured to be detachably attachable to the rotation shaft, and the first stock guide110a, the second stock guide110b, and the squeegee roll105can be detached from the squeegee device as needed. If the first stock guide110a, the second stock guide110b, or the squeegee roll105needs to be replaced due to wear or other reasons, only the member to be replaced can thus be replaced easily. This reduces the effort for member replacement and increases the continuous operation period of the production apparatus100, whereby the electrode active material layer3can be stably produced.

As shown inFIG.3, the first stock guide110ahas a first surface111afacing the peripheral surface of the forming roll101, which serves as a support unit, via the substrate1.

The second stock guide110balso has a second surface111bfacing the peripheral surface of the forming roll101, which serves as a support unit, via the substrate1.

The first surface111aand the second surface111bboth have a shape that conforms to the peripheral surface of the forming roll101serving as the support unit. In the present embodiment, the first surface111aand the second surface111bare concave curved surfaces having substantially the same radius of curvature as that of the forming roll101, and preferably a radius of curvature that is 95% or more and 110% or less of the radius of curvature of the forming roll101. Since the first surface111aand the second surface111bhave a shape that conforms to the peripheral surface of the forming roll101, it is possible to reduce the leakage of the granulated particles P, which have been fed above the forming roll101, from a gap between the first surface111aof the first stock guide110aand the main surface of the substrate1supported by the peripheral surface of the forming roll101, and from a gap between the second surface111bof the second stock guide110band the main surface of the substrate1supported by the peripheral surface of the forming roll101, to the outer side in the direction of the axis R101of the forming roll101. The gap amount G1between the first surface111aof the first stock guide110aand the main surface of the substrate1to which the granulated particles P are fed and the gap amount G2between the second surface111bof the second stock guide110band the main surface of the substrate1to which the granulated particles P are fed can be adjusted by the first gap amount adjustment unit131aand the second gap amount adjustment unit131b, to be described below, respectively.

The first position measurement unit120ais fixed to a first end face112aof the first stock guide110aopposite to the first surface111a. The second position measurement unit120bis fixed to a second end face112bof the second stock guide110bopposite to the second surface111b. The first position measurement unit120aand the second position measurement unit120bcan be measuring instruments such as a laser displacement meter. Since the first position measurement unit120ais fixed to the first stock guide110a, the first position measurement unit120amoves up and down with the first stock guide110awhen the first gap amount adjustment unit131ato be described below moves the first stock guide110aup and down. Similarly, since the second position measurement unit120bis fixed to the second stock guide110b, the second position measurement unit120balso moves up and down with the second stock guide110bwhen the second gap amount adjustment unit131bto be described below moves the second stock guide110bup and down. The first position measurement unit120acan thus measure a distance (distance D1) corresponding to the gap amount G1. The second position measurement unit120bcan measure a distance (distance D2) corresponding to the gap amount G2.

A first slit113aserving as a first through-hole is provided in the first stock guide110ato run through from the first end face112a, to which the first position measurement unit120ais fixed, to the first surface111a. The first slit113ais provided to be parallel to the main surface of the first stock guide110a. In the present embodiment, the first position measurement unit120aemits laser light from a not-shown laser emission port. The emitted laser light passes through the first slit113aand is reflected by the surface, to which the granulated particles P are fed, opposite to the first surface111a. In another embodiment, the first slit113adoes not need to be parallel to the main surface of the first stock guide110a.

The reflected laser light passes through the first slit113aand is received by a not-shown photoreceptor unit of the first position measurement unit120a, whereby the distance D1between the first position measurement unit120aand the surface to which the granulated particles P are fed can be measured.

Like the first stock guide110a, the second stock guide110bhas a second slit113bserving as a second through-hole, which runs through from the second end face112b, to which the second position measurement unit120bis fixed, to the second surface111b. The second slit113bis provided to be parallel to the main surface of the second stock guide110b. The second position measurement unit120bcan measure the distance D2between the second position measurement unit120band the surface to which the granulated particles P are fed. In another embodiment, the second slit113bdoes not need to be parallel with the main surface of the second stock guide110b.

In the present embodiment, the first through-hole and the second through-hole both have a slit shape. However, in another embodiment, the first through-hole and the second through-hole may have a cylindrical shape each.

The first position measurement unit120aand the second position measurement unit120bare fixed to the first stock guide110aand the second stock guide110b, respectively, and the first slit113aand the second slit113bare provided to measure the distance D1and the distance D2. This can reduce rattling of the first position measurement unit120aand the second position measurement unit120band improve the measurement accuracy of the distances D1and D2.

The first position measurement unit120aand the second position measurement unit120bare both electrically connected to the control unit140to be described below.

As shown inFIG.1, the first stock guide110ais provided with the first gap amount adjustment unit131afor adjusting the gap amount G1. The second stock guide110bis provided with the second gap amount adjustment unit131bfor adjusting the gap amount G2. An optional mechanism such as an elevating mechanism including a servo motor and a ball screw may be used as the mechanism for adjusting the gap amount G1or the gap amount G2. In the present embodiment, a nut is fixed to each of the first stock guide110aand the second stock guide110b. A ball screw to mesh with the nut is situated along a direction orthogonal to the axis R101of the forming roll101. A servo motor is attached to the end portion of the ball screw so that the ball screw can be driven to rotate.

As described above, the squeegee roll105is provided with the position adjustment mechanism so that the distance between the peripheral surface of the squeegee roll105and the peripheral surface of the forming roll101serving as the first conveying unit can be adjusted. The first gap amount adjustment unit131aand the second gap amount adjustment unit131bare configured so that the gap amount G1and the gap amount G2can be adjusted, respectively, independent of the adjustment of the distance between the peripheral surface of the squeegee roll105and the peripheral surface of the forming roll101.

The first gap amount adjustment unit131aand the second gap amount adjustment unit131bare both electrically connected to the control unit140to be described below. The first gap amount adjustment unit131aand the second gap amount adjustment unit131beach receive a control signal from the control unit140. Based on the signal from the control unit140, the first gap amount adjustment unit131aadjusts the gap amount G1, and the second gap amount adjustment unit131badjusts the gap amount G2. In the present embodiment, the first gap amount adjustment unit131athat is a servo motor rotates the ball screw in a specified direction of rotation by a specified amount of rotation based on the signal from the control unit140. The second gap amount adjustment unit131bthat is a servo motor rotates the ball screw in a specified direction of rotation by a specified amount of rotation based on the signal from the control unit140. The gap amount G1and the gap amount G2can thus be independently adjusted by independently moving the first stock guide110aand the second stock guide110bup and down.

The rolling unit130includes the forming roll101functioning as a rolling roll and the rolling roll130a. The rolling roll130ais a cylindrical member, and is driven to rotate about the axis R130aat a constant speed in a direction in which the substrate1and the granulated particle layer2are conveyed downstream. The axis R101and the axis R130aare disposed to be parallel to each other. A gap is provided between the peripheral surface of the forming roll101and the peripheral surface of the rolling roll130a. The granulated particle layer2is guided into the gap between the forming roll101and the rolling roll130a. In the present embodiment, the granulated particle layer2is formed on the substrate1, and the stacked body of the substrate1and the granulated particle layer2is guided into the gap between the forming roll101and the rolling roll130a. The granulated particle layer2stacked on the substrate1is rolled to be brought into close contact with the substrate1when passing through the gap between the forming roll101and the rolling roll130a, whereby the electrode active material layer3having a predetermined thickness is formed on the substrate1.

The gap (distance) between the peripheral surface of the forming roll101and the peripheral surface of the rolling roll130acan be adjusted as appropriate depending on the desired thickness, porosity, etc., of the electrode active material layer3.

Examples of the material constituting the peripheral surfaces of the forming roll101and the rolling roll130amay include a rubber, metal, and an inorganic material.

The rolling roll130amay have a mechanism for heating the peripheral surface thereof. This configuration can roll the granulated particle layer2while heating it. By rolling the granulated particle layer2while heating, the binder contained in the granulated particles P can be softened or melted. As a result, the granulated particles P can be more firmly bound to each other.

As illustrated inFIG.4, the control unit140is electrically connected to the first position measurement unit120a, the second position measurement unit120b, the first gap amount adjustment unit131a, and the second gap amount adjustment unit131b.FIGS.5and6are flowcharts for describing processing performed by the control unit140according to the first embodiment.

As shown inFIG.4, the control unit140includes a data acquisition unit141, a gap amount calculation unit142, a storage unit143, a gap amount adjustment amount determination unit144, an adjustment determination unit145, and a gap amount adjustment instruction unit146.

The data acquisition unit141acquires data on the distance D1from the first position measurement unit120a(step S11).

The gap amount calculation unit142calculates the gap amount G1between the first surface111aof the first stock guide110aand the main surface of the substrate1, which is a surface to which the granulated particles P are fed, based on the data on the distance D1and dimension data on the first stock guide110astored in the storage unit143(step S12).

The gap amount adjustment amount determination unit144determines the adjustment amount ΔG1for the gap amount G1based on a difference between the calculated gap amount G1and a gap amount threshold T1stored in the storage unit143(step S13). A value greater than 0 μm is set as the gap amount threshold T1.

The adjustment determination unit145determines whether the adjustment amount ΔG1for the gap amount G1is 0 (whether the gap amount G1needs to be adjusted) (step S14). If ΔG1is 0 (step S14: Yes), the processing returns to step S11.

If ΔG1is not 0 (step S14: No), the gap amount adjustment instruction unit146instructs the first gap amount adjustment unit131ato make an adjustment by the determined adjustment amount ΔG1(step S15).

The first gap amount adjustment unit131amoves the first stock guide110aup or down based on the instructed adjustment amount ΔG1to adjust the gap amount G1(step S16).

Similarly, the data acquisition unit141acquires data on the distance D2from the second position measurement unit120b(step S21).

The gap amount calculation unit142calculates the gap amount G2between the second surface111bof the second stock guide110band the main surface of the substrate1, i.e., the surface to which the granulated particles P are fed based on the data on the distance D2and dimension data on the second stock guide110bstored in the storage unit143(step S22).

The gap amount adjustment amount determination unit144determines the adjustment amount ΔG2for the gap amount G2based on a difference between the calculated gap amount G2and a gap amount threshold T2stored in the storage unit143(step S23). A value greater than 0 μm is set as the gap amount threshold T2.

The adjustment determination unit145determines whether the adjustment amount ΔG2for the gap amount G2is 0 (whether the gap amount G2needs to be adjusted) (step S24). If ΔG2is 0 (step S24: Yes), the processing returns to step S21.

If ΔG2is not 0 (step S24: No), the gap amount adjustment instruction unit146instructs the second gap amount adjustment unit131bto make an adjustment by the determined adjustment amount ΔG2(step S25).

The second gap amount adjustment unit131bmoves the second stock guide110bup or down based on the instructed adjustment amount ΔG2to adjust the gap amount G2(step S26).

The control unit140may perform the processing for causing the first gap amount adjustment unit131ato adjust the gap amount G1and the processing for causing the second gap amount adjustment unit131bto adjust the gap amount G2in parallel or in sequence.

The control unit140may include a distance prediction unit150.

FIG.7is a schematic diagram showing a configuration of the control unit140including the distance prediction unit150according to the first embodiment. The control unit140includes the distance prediction unit150in addition to the data acquisition unit141, the gap amount calculation unit142, the storage unit143, the gap amount adjustment amount determination unit144, the adjustment determination unit145, and the gap amount adjustment instruction unit146. The control unit140is electrically connected to the first position measurement unit120a, the second position measurement unit120b, the first gap amount adjustment unit131a, and the second gap amount adjustment unit131b.

The distance prediction unit150includes a data set acquisition unit151, a data set analysis unit152, and a predicted distance data storage unit153.

FIGS.8and9are flowcharts for describing processing performed by the control unit140including the distance prediction unit150.

The data set acquisition unit151acquires a data set A1on the distance D1during a period in which the forming roll101serving as the support unit rotates two revolutions or more (step S101).

The data set analysis unit152analyzes the acquired data set A1and predicts the distance D1, which varies depending on the rotation of the forming roll101(step S102).

The predicted distance data storage unit153stores the predicted distance D1in the storage unit143(step S103).

The gap amount calculation unit142calculates the gap amount G1between the first surface111aof the first stock guide110aand the main surface of the substrate1, i.e., the surface to which the granulated particles P are fed based on the data on the predicted distance D1and the dimension data on the first stock guide110a, stored in the storage unit143(step S104).

The gap amount adjustment amount determination unit144determines the adjustment amount ΔG1for the gap amount G1based on a difference between the calculated gap amount G1and the gap amount threshold T1stored in the storage unit143(step S105). A value greater than 0 μm is set as the gap amount threshold T1.

The adjustment determination unit145determines whether the adjustment amount ΔG1for the gap amount G1is 0 (whether the gap amount G1needs to be adjusted) (step S106). If ΔG1is 0 (step S106: Yes), the processing returns to step S104.

If ΔG1is not 0 (step S106: No), the gap amount adjustment instruction unit146instructs the first gap amount adjustment unit131ato make an adjustment by the determined adjustment amount ΔG1(step S107).

The first gap amount adjustment unit131amoves the first stock guide110aup or down to adjust the gap amount G1based on the instructed adjustment amount ΔG1(step S108).

The data set acquisition unit151acquires a data set A2on the distance D2during a period in which the forming roll101serving as the support unit rotates two revolutions or more (step S201).

The data set analysis unit152analyzes the acquired data set A2and predicts the distance D2, which varies depending on the rotation of the forming roll101(step S202).

The predicted distance data storage unit153stores the predicted distance D2in the storage unit143(step S203).

The gap amount calculation unit142calculates the gap amount G2between the second surface111bof the second stock guide110band the main surface of the substrate1, i.e., the surface to which the granulated particles P are fed based on the data on the predicted distance D2and the dimension data on the second stock guide110b, stored in the storage unit143(step S204).

The gap amount adjustment amount determination unit144determines the adjustment amount ΔG2for the gap amount G2based on a difference between the calculated gap amount G2and the gap amount threshold T2stored in the storage unit143(step S205). A value greater than 0 μm is set as the gap amount threshold T2.

The adjustment determination unit145determines whether the adjustment amount ΔG2for the gap amount G2is 0 (whether the gap amount G2needs to be adjusted) (step S206). If ΔG2is 0 (step S206: Yes), the processing returns to step S204.

If ΔG2is not 0 (step S206: No), the gap amount adjustment instruction unit146instructs the gap amount adjustment unit131bto make an adjustment by the determined adjustment amount ΔG2(step S207).

The second gap amount adjustment unit131bmoves the second stock guide110bup or down to adjust the gap amount G2based on the instructed adjustment amount ΔG2(step S208).

The control unit140including the distance prediction unit150predicts the variable distances D1and D2, and causes the first gap amount adjustment unit131ato adjust the gap amount G1and causes the second gap amount adjustment unit131bto adjust the gap amount G2based on the predicted distances D1and D2. The adjustment amounts ΔG1and ΔG2can thus easily follow variations in the distances D1and D2. This reduces the leakage of the granulated particles P, which have been fed above the forming roll101, from the gap between the first surface111aof the first stock guide110aand the main surface of the substrate1supported by the peripheral surface of the forming roll101, and from the gap between the second surface111bof the second stock guide110band the main surface of the substrate1supported by the peripheral surface of the forming roll101, to the outer side in the direction of the axis R101of the forming roll101. This can also prevent the gap amount G1and the gap amount G2from being 0 μm, and thereby reduce the first stock guide110aand the second stock guide110bcoming into contact with the substrate1and distorting the substrate1. The reduced distortion of the substrate1can suppress breakage of the substrate1and improve the production stability of the electrode active material layer3.

The control unit140may perform the processing for predicting the distance D1and the processing for predicting the distance D2in parallel or in sequence.

The data set analysis unit152can analyze the data set A1or the data set A2using a conventional known method. Examples of the analysis method may include time series analysis. The variable distance D1or D2can be predicted by analyzing the acquired data set A1or A2with the circumferential length of the forming roll101as a unit of repetition.

The predicted distances D1and D2may be predicted as a function with the rotation angle of the forming roll101as a variable, for example.

The functions of the control unit140may be implemented by a computer including an input interface, an output interface, a CPU (Central Processing Unit), and a storage device (such as a ROM (Read Only Memory) and a RAM (Random Access Memory)). The first position measurement unit120aand the second position measurement unit120bare connected to the input interface. The first gap amount adjustment unit131aand the second gap amount adjustment unit131bare connected to the output interface. The CPU and the storage device are connected to each other by buses. The storage device stores programs. The CPU executes the programs stored in the storage device.

The production apparatus100is configured so that the gap amount G1between the first surface111aof the first stock guide110aand the surface to which the granulated particles P are fed (in the present embodiment, the main surface of the substrate1) and the gap amount G2between the second surface111bof the second stock guide110band the surface to which the granulated particles P are fed (in the present embodiment, the main surface of the substrate1) become both larger than 0 μm. As a result, it is possible to reduce occurrence of distortion in the substrate1due to contact of the first stock guide110aand the second stock guide110bwith the substrate1. As a result of reducing distortion in the substrate1, breakage of the substrate1can be suppressed, and production stability of the electrode active material layer3can be improved.

The gap amount threshold T1and the gap amount threshold T2can be both set to any value greater than 0 μm. For example, the gap amount threshold T1and the gap amount threshold T2each can be preferably less than or equal to a 10% number-average particle diameter (D10) of the granulated particles P, more preferably less than or equal to a 5% number-average particle diameter (D5), and further preferably less than or equal to a 38 number-average particle diameter (D3). The lower limit value is greater than 0% of the volume-average particle diameter (D50) the granulated particles P usually have.

With both the gap amount thresholds T1and T2less than or equal to the above-mentioned upper limit value, the leakage of the granulated particles P, which has been fed above the forming roll101, from the gap between the first surface111aof the first stock guide110aand the main surface of the substrate1supported by the peripheral surface of the forming roll101, and from the gap between the second surface111bof the second stock guide110band the main surface of the substrate1supported by the peripheral surface of the forming roll101, to the outer side in the direction of the axis R101of the forming roll101can be effectively reduced. This can effectively reduce the leaked granulated particles P being conveyed to the rolling unit130and rolled with the granulated particle layer2. Defective formation of the resulting electrode active material layer3can thereby be effectively suppressed. Since the leakage of the granulated particles P can be effectively reduced, the yield of the granulated particles P can be improved to reduce the production costs of the electrode active material layer3.

In another embodiment, the production apparatus may further include a height sensor for measuring the height of the fed granulated particles upstream of the squeegee device, and a control unit for adjusting the amount of granulated particles to be fed from the feeding unit based on information from the height sensor. Fluctuations in the weight per unit area (basis weight) of the electrode active material layer3obtained by rolling the granulated particle layer2can thereby be reduced to adjust the basis weight with high precision.

In the production apparatus according to the present invention, an optional configuration may be disposed as necessary in addition to the above-described configuration.

For example, a coating unit that is disposed upstream of the feeding unit of the production apparatus and that applies a binder coating liquid onto the substrate can be included as an optional configuration. If the production apparatus includes the coating unit, the binder coating liquid can be applied onto the substrate to form a binder coating liquid layer and the granulated particles can be fed onto the binder coating liquid layer. This can make the granulated particles come into close contact with the substrate. Examples of the coating unit may include a slot die head, a gravure head, a bar coat head, and a knife coat head.

The production apparatus can include a collection unit that collects the substrate on which the electrode active material layer has been formed, downstream of the rolling unit. Examples of the collection unit may include a roll for winding up the substrate.

2. Second Embodiment

Next, a production apparatus of an electrode active material layer according to a second embodiment will be described.

FIG.10is a schematic diagram illustrating the production apparatus of an electrode active material layer according to the second embodiment.

A production apparatus200according to the present embodiment includes a forming roll201, a feeding unit103, a second conveying unit202, a squeegee roll105serving as a squeegee unit, a first stock guide110a, a second stock guide110b, a first position measurement unit120a, a second position measurement unit120b, a rolling roll230b, a first gap amount adjustment unit131a, a second gap amount adjustment unit131b, and a control unit140. The forming roll201functions as a support unit, a first conveying unit, and a rolling unit.

The feeding unit103feeds granulated particles P onto the forming roll201of the production apparatus200, or more specifically, onto the peripheral surface of the forming roll201serving as the support unit. The forming roll201serving as the first conveying unit rotates in a direction DR201to thereby convey the granulated particles P downstream. The squeegee roll105rotates in a direction DR105opposite to the direction DR201, whereby the granulated particles P fed onto and conveyed on the peripheral surface of the forming roll201are leveled to a predetermined thickness to form a granulated particle layer2.

The forming roll201is paired with the rolling roll230bto form the rolling unit230. The rolling roll230bis a cylindrical member and is driven to rotate about an axis R230bat a constant speed in the direction in which the substrate1and the granulated particle layer2are conveyed downstream. An axis R201of the forming roll201and the axis R230bof the rolling roll230bare disposed to be parallel to each other. A gap is provided between the peripheral surface of the forming roll201and the peripheral surface of the rolling roll230b. As the forming roll201rotates, the granulated particle layer2conveyed by the peripheral surface of the forming roll201is guided into the gap between the forming roll201and the rolling roll230b.

The second conveying unit202is a conveying roll, for example, and conveys the substrate1to the rolling unit230. Specifically, the second conveying unit202conveys the substrate1to the peripheral surface of the rolling roll230bconstituting the rolling unit230. As the rolling roll230brotates, the substrate1is guided into the gap between the forming roll201and the rolling roll230b.

The granulated particle layer2and the substrate1are guided into the gap between the forming roll201and the rolling roll230b, and stacked. When passing through the gap between the forming roll201and the rolling roll230b, the granulated particle layer2and the substrate1are rolled to form an electrode active material layer3having a predetermined thickness on the substrate1.

The gap between the peripheral surface of the forming roll201and the peripheral surface of the rolling roll230bcan be adjusted as appropriate depending on the desired thickness, porosity, etc., of the electrode active material layer3. Examples of the material constituting the peripheral surface of the rolling roll230bmay include the materials mentioned in the description of the rolling roll130b. The rolling roll230bmay include a mechanism for heating its peripheral surface.

Like the production apparatus100, the production apparatus200is configured so that the gap amount G1between the first surface111aof the first stock guide110aand the surface to which the granulated particles P are fed (in the present embodiment, the peripheral surface of the forming roll201serving as the support unit) and the gap amount G2between the second surface111bof the second stock guide110band the surface to which the granulated particles P are fed (in the present embodiment, the peripheral surface of the forming roll201serving as the support unit) become both larger than 0 μm. This reduces the first stock guide110aand the second stock guide110bcoming into contact with the forming roll201and being worn by the same. As a result, the production stability of the electrode active material layer3can be improved.

The production apparatus200includes the first stock guide110a, the second stock guide110b, the first position measurement unit120a, the second position measurement unit120b, the first gap amount adjustment unit131a, the second gap amount adjustment unit131b, and the control unit140, which are configured the same as those of the production apparatus100. Like the production apparatus100, the production apparatus200can thus effectively reduce the leakage of the granulated particles P, which have been fed onto the forming roll201, from the gap between the first surface111aof the first stock guide110aand the peripheral surface of the forming roll201, and from the gap between the second surface111bof the second stock guide110band the peripheral surface of the forming roll201, to the outer side in the direction of the axis R201of the forming roll201. This can effectively reduce the leaked granulated particles P being conveyed to the rolling unit230and rolled together with the granulated particle layer2. Defective formation of the resulting electrode active material layer3can thereby be effectively suppressed. Since the leakage of the granulated particles P can be effectively reduced, the yield of the granulated particles P can be improved to reduce the production costs of the electrode active material layer3.

Next, a production apparatus of an electrode active material layer according to a third embodiment will be described.

FIG.11is a schematic diagram showing the production apparatus of an electrode active material layer according to the third embodiment.FIG.12is a top view schematically showing a part of the production apparatus according to the third embodiment.FIG.13is a side view schematically showing a part of the production apparatus according to the third embodiment.

A production apparatus300according to the present embodiment includes a support unit301, a feeding unit103, a third conveying unit104, a pair of rolling rolls330aand330bserving as a first conveying unit and a rolling unit, a squeegee roll105serving as a squeegee unit, a first stock guide310a, a second stock guide310b, a first position measurement unit120a, a second position measurement unit120b, a first gap amount adjustment unit131a, a second gap amount adjustment unit131b, and a control unit140.

In the present embodiment, the support unit301has a board-like shape. The feeding unit103feeds the granulated particles P onto the main surface of a substrate1supported by the support unit301above the support unit301. In other words, the surface to which the granulated particles P are fed is the main surface of the substrate1. The rolling rolls330aand330bserving as the first conveying unit rotate in opposite directions to thereby convey the substrate1and the granulated particles P fed onto the main surface of the substrate1downstream.

The squeegee roll105is configured so that the distance between the peripheral surface of the squeegee roll105and the support unit301can be adjusted.

As shown inFIG.12, the first stock guide310ahaving a plate shape is disposed in parallel with a first end face105E1of the squeegee roll105. The second stock guide310bhaving a plate shape is disposed in parallel with a second end face105E2of the squeegee roll105.

A distance W310between the main surface of the first stock guide310aon the squeegee roll105side and the main surface of the second stock guide310bon the squeegee roll105side corresponds to the width of the electrode active material layer3to be produced.

As shown inFIG.13, the first stock guide310ahas a first surface311afacing the main surface of the support unit301via the substrate1.

The second stock guide310bhas a second surface311bfacing the main surface of the support unit301via the substrate1.

The first surface311aand the second surface311bboth have a flat shape conforming to the main surface of the support unit301.

The first stock guide310aand the second stock guide310bare provided so that the first surface311aand the second surface311bare parallel to the main surface of the support unit301, respectively.

A first slit313aserving as a first through-hole is provided in the first stock guide310ato run through from a first end face312a, to which the first position measurement unit120ais fixed, to the first surface311a. The first slit313ais provided to be parallel to the main surface of the first stock guide310a. Like the first stock guide310a, the second stock guide310bhas a second slit313bserving as a second through-hole, which runs through from a second end face312b, to which the second position measurement unit120bis fixed, to the second surface311b. The second slit313bis provided to be parallel to the main surface of the second stock guide310b. The first position measurement unit120aand the second position measurement unit120bare fixed to the first stock guide310aand the second stock guide310b, respectively, and the first slit313aand the second slit313bare provided to measure the distance D1and the distance D2. This can reduce rattling of the first position measurement unit120aand the second position measurement unit120band improve the measurement accuracy of the distances D1and D2.

In the present embodiment, the first through-hole and the second through-hole both have a slit shape. However, in another embodiment, the first through-hole and the second through-hole may have a cylindrical shape each.

In another embodiment, the first slit313adoes not need to be parallel to the main surface of the first stock guide310a. The second slit313bdoes not need to be parallel to the main surface of the second stock guide310b.

The paired rolling rolls330aand330bare configured to function as the first conveying unit and the rolling unit as well. The paired rolling rolls330aand330bare disposed so that the rotation axes R330a, R330bare parallel to each other. In the present embodiment, the support unit301and the paired rolling rolls330a,330bare disposed so that a plane including the rotation axis R330aof the rolling roll330aand the rotation axis R330bof the rolling roll330bis orthogonal to a plane including the main surface of the support unit301.

Like the production apparatus100, the production apparatus300is configured so that the gap amount G1between the first surface311aof the first stock guide310aand the surface to which the granulated particles P are fed (in the present embodiment, the main surface of the substrate1) and the gap amount G2between the second surface311bof the second stock guide310band the surface to which the granulated particles P are fed (in the present embodiment, the main surface of the substrate1) become both larger than 0 μm. This reduces occurrence of distortion in the substrate1due to the contact of the first stock guide310aand the second stock guide310bwith the substrate1. The reduced distortion of the substrate1can suppress breakage of the substrate1and improve the production stability of the electrode active material layer3.

<4. Modification of Third Embodiment>

Next, a production apparatus of an electrode active material layer according to a modification of the third embodiment will be described.

FIG.14is a schematic diagram illustrating the production apparatus according to the modification of the third embodiment.

A production apparatus400includes the support unit301and the pair of rolling rolls330aand330b, which are disposed so that the plane including the rotation axis R330aof the rolling roll330aand the rotation axis R330bof the rolling roll330bis parallel to the plane including the main surface of the support unit301.

Like the production apparatus300, the production apparatus400reduces occurrence of distortion in the substrate1due to the contact of the first stock guide310aand the second stock guide310bwith the substrate1. The reduced distortion of the substrate1can suppress breakage of the substrate1and improve the production stability of the electrode active material layer3.

REFERENCE SIGN LIST