JP7154807B2 - METHOD FOR MANUFACTURING ELECTRODE SHEET FOR LITHIUM ION SECONDARY BATTERY - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing an electrode sheet for lithium ion secondary batteries.

Secondary batteries, which are a type of electrochemical device, are widely used as power sources for portable electronic devices such as mobile phones, digital cameras, and laptop computers, power sources for vehicles, and power sources for households. An electrochemical device has an electrode laminate in which two types of electrode sheets (a positive electrode sheet and a negative electrode sheet) are laminated via a separator. Each electrode sheet is formed by forming an active material layer on a metallic collector foil.

In particular, with the increasing demand for electric vehicles in light of environmental problems in recent years, there is a demand for higher energy density and higher capacity for secondary batteries, which are the driving source of these vehicles. Laminated type batteries, which are easy to increase in size, have come to be selected.

An electrode for a secondary battery is produced from an electrode sheet obtained by applying a slurry containing an active material onto a sheet-like collector foil made of aluminum, copper, or the like, and drying the applied slurry. Specifically, a current collector foil on which an active material layer is formed by applying and drying a slurry is once wound into a roll, and then the current collector foil is cut into predetermined lengths to produce a plurality of electrode sheets. ing. The method of applying the slurry containing the active material can be broadly classified into an intermittent coating method and a continuous coating method.
In the above-described laminated type battery, when the electrode area is increased, a coated region formed by coating a sheet-shaped current collector foil with a slurry containing an active material and a non-coated region where the slurry is not coated are divided into current collectors. An electrode sheet manufactured by an intermittent coating method, in which the electrodes are alternately formed at predetermined intervals in the winding direction of the foil, is often used.

In addition, electrodes used in secondary batteries designed to have a high energy density require high-density compression of the active material layer. There is a tendency to design thin thickness.

Japanese Patent Application Laid-Open No. 2004-214140 JP-A-2003-223899 Japanese Patent No. 4284760 JP-A-2002-124249 Japanese Patent Application Laid-Open No. 2003-208890 JP 2007-172878 A

In a method for producing an electrode sheet for an electrochemical device (for example, a lithium ion secondary battery) that has been widely used in recent years, as described in Patent Documents 1 to 6, an active material is applied to both sides of a sheet-like current collector foil, respectively. After forming the layer, pressing (rolling) processing is performed to compress the active material layer formed on the current collector foil in the thickness direction. As a result, an electrode sheet having active material layers with a desired density and thickness on both sides of the current collector foil can be formed.

When manufacturing an electrode sheet having active material layers on both sides of a current collector foil, a slurry containing an active material is applied to both sides of the current collector foil. When the slurry is applied to the current collector foil using the above-described intermittent coating method, the coating start point, that is, the formation start point (starting end) of the active material layer, may locally swell and become thick. . If pressing (rolling) is performed in this state, there is a risk of cracking or chipping of the active material layer at the thick portion of the active material layer. Therefore, in the method described in Patent Document 1, the leading edge of one surface of the current collector foil and the leading edge of the other surface are positioned apart from each other by 0.5 to 2.9 mm in the length direction of the current collector foil. Slurry application start points are shifted on both sides of the current collector foil. As a result, the positions of the protrusions (starting ends) of the active material layers on both sides of the current collector foil are displaced in the length direction. As a result, it is possible to avoid a state in which the bulges on both sides of the current collector foil are pressed at the same time. In the methods described in Patent Documents 2 to 4, the traveling direction of the current collector foil when applying the active material to one surface of the current collector foil and the movement direction of the current collector foil when the active material is applied to the other surface. The direction of travel is reversed. As a result, the starting end of one surface of the current collecting foil and the starting end of the other surface of the current collecting foil are positioned apart from each other in the length direction of the current collecting foil. It is possible to suppress a decrease in adhesion strength between the active material layer of the negative electrode and the current collector foil, which is caused by swelling of the starting end portion of the active material layer.

In the method described in Patent Document 5, the density of the active material layer at the raised start end is 1.02 to 1.50 times higher than the density at the portion other than the start end. In the structure described in Patent Document 6, the density of the positive electrode active material layer decreases from the starting end to the terminal end, and the density of the negative electrode active material layer increases from the starting end to the terminal end.

According to the methods described in Patent Literatures 1 to 4, extremely high pressure is not applied to the collector foil and part of the active material layer, and the possibility that the active material layer is severely damaged is reduced. However, this alone does not eliminate manufacturing defects in electrode sheets. For example, pieces of the active material may adhere to the collector foil in the non-applied area, causing problems. In addition, in the method described in Patent Document 5, since the raised starting end of the active material layer is particularly strongly compressed, the possibility of damaging the active material layer is rather high. In the method described in Patent Document 6, the depth of discharge is balanced in a state in which the positive electrode and the negative electrode are laminated. However, no consideration is given to the possibility of breakage occurring during the manufacture of the individual electrodes themselves (particularly during the compression process). Thus, it is desired to more reliably suppress the occurrence of problems such as breakage and scattering of the active material layer during the manufacture of individual electrodes.

Accordingly, an object of the present invention is to provide a method for producing an electrode sheet for a lithium ion secondary battery, which is less likely to cause problems during production.

In the method of manufacturing an electrode sheet in which an active material layer is formed on a sheet-like current collector foil of the present invention, a slurry containing an active material is intermittently applied to the sheet-like current collector foil, and a slurry application region and a A coating step of winding the current collector foil along the winding direction while alternately forming the non-coated regions in the winding direction of the sheet-like current collector foil; and an active material layer formed on the current collector foil. In the compression step, the active material layer is compressed from the formation start point side to the formation end point side in the formation direction of the active material layer in the coating step. After the coating process is completed, the current collecting foil having the active material layer formed thereon is wound into a roll, and then the current collecting foil having the active material layer formed thereon is rewound to form a secondary roll; A compression step is performed on the current collector foil on which the active material layer is formed, which is unwound from the next roll.

According to the present invention, the possibility of causing problems during the production of the electrode sheet is reduced.

FIG. 4 is a front view schematically showing the first half of the coating step in the method for manufacturing an electrode sheet according to one embodiment of the present invention; 1B is a front view schematically showing the second half of the coating step in the method for manufacturing the electrode sheet shown in FIG. 1A; FIG. It is a front view which shows typically the compression process of the manufacturing method of the electrode sheet shown to FIG. 1A and 1B. FIG. 10 is a front view schematically showing a state in which a problem has occurred due to breakage of the active material layer in the compression step; It is a front view which shows the compression process of the 1st Embodiment of this invention. FIG. 11 is a front view showing first stage compression of the compression process of the second embodiment of the present invention; It is a front view which shows the state following FIG. 4A. FIG. 11 is a front view showing the second stage compression of the compression process of the second embodiment of the invention; It is a front view which shows the state following FIG. 4C. 4 is a graph showing the relationship between the linear pressure in the compression process and the density of the compressed active material layer.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings.
The electrode sheet manufactured by the method according to the present invention is used in lithium ion secondary batteries. A lithium-ion secondary battery has a configuration in which an electrode laminate, in which two kinds of electrode sheets (a positive electrode and a negative electrode) are alternately laminated via a separator, is housed in an outer container together with an electrolytic solution. A specific manufacturing method of this electrode sheet is shown only for the negative electrode 1 in FIGS. 1A to 4D. However, although illustration and description are omitted, the positive electrode can also be manufactured in the same manner as the negative electrode 1 .

As shown in FIG. 1A, a slurry containing an active material is applied to one surface of a sheet-like collector foil 1a to form an active material layer 1b. Then, as shown in FIG. 1B, the same slurry is applied to the other surface of the current collector foil 1a to form an active material layer 1b. Thus, the active material layers 1b are formed on both surfaces of the current collector foil 1a (coating step). At this time, the current collector foil 1a on which the active material layer 1b is formed by applying and drying the slurry is once wound into a roll, and then the current collector foil 1a is cut into predetermined lengths to form a plurality of electrode sheets (negative electrode sheets). 1) is produced. The position of the starting end 1b1 of the active material layer 1b in the winding direction of the current collector foil 1a is substantially the same on both sides of the current collector foil 1a.

After performing the coating process shown in FIGS. 1A and 1B, the compression process is performed. In the compression step, as shown in FIG. 1C, the current collector foil 1a and the active material layer 1b are sandwiched between a pair of rollers 2, and the rollers 2 are rotated to send out the current collector foil 1a and the active material layer 1b. At this time, since the gap between the pair of rollers 2 is constant, the active material layer 1b sandwiched between the pair of rollers 2 is pressed by both rollers 2 and compressed to a predetermined density (for example, 1. 66 g/cc). In the manufacturing method of such an electrode sheet, in the present embodiment, the active material coating starting point in the coating step, that is, the active material layer formation starting point (starting end), the active material coating ending point, that is, the active material layer and the direction from the compression start point (press start point) of the active material layer in the compression step to the compression end point (press end point) of the active material layer coincides. there is As a result, it is possible to suppress the occurrence of defective products at the time of manufacturing the electrode sheet. The reason for this and the technical significance of the present invention will be described below.

Electrode 1 used in a lithium ion secondary battery is generally manufactured by forming active material layer 1b on collector foil 1a and then compressing active material layer 1b to a desired density. Therefore, when manufacturing a large number of electrodes 1, the active material layer 1b is formed continuously or intermittently on the sheet-like collector foil 1a. At this time, the formation starting point (starting end) of the active material layer is locally raised and thickened. For example, the roller 2 feeding the sheet-like current collector foil 1a so that the length of the coating area of each active material layer 1b intermittently formed in the coating process is 227 mm and the basis weight is 12.7 mg/cm ² . The rotation speed was set to 30 m/min. Then, a slurry containing water as a dispersion medium and styrene-butadiene copolymer rubber (SBR) as a binder was measured with a Brookfield viscometer (Rotational viscometer manufactured by Brookfield) at a shear rate of 3 at 25°C. The viscosity was adjusted to be in the range of 5,000 mPa·s to 10,000 mPa·s when measured under the condition of .4 s ⁻¹ . Under these conditions, when the slurry is applied using a die coater, the average thickness of the range within 10 mm, which corresponds to 4.4% of the length of the application area of each active material layer 1b from the formation start point, is Thicker in the range of 2% or more and 5% or less than the average thickness in the range exceeding 10 mm from the formation start point in the process (in each drawing, the swell at the formation start point is exaggerated for clarity) there). After that, the current collector foil 1a with the active material layer 1b formed thereon is conveyed to a pressure member (for example, a pair of rollers 2) to press and compress the active material layer 1b. Defects may occur in the compression step of compressing the active material layer 1b by applying pressure. When the applicant of the present invention considered the cause of this defect, as schematically shown in FIG. , the problem that it sometimes adheres to the current collector foil 1a in the non-coated area was found. When the active material layer piece 1b2 (see FIG. 2) adheres to the current collector foil 1a in the non-coated area in this way, it may damage other current collector foils overlapping this current collector foil 1b, and the required size, shape, It may become impossible to manufacture the electrode 1 with performance. 2 to 4D, for the sake of convenience, the active material layer 1b located on the lower side of the drawing is omitted.

In contrast, the applicant devised the feeding direction of the current collector foil 1a having the active material layer 1b formed thereon, which was pressed in the compression step, so that when the active material layer 1b was pressed, the active material layer was compressed. It was found that it is possible to prevent a part of the particles from scattering and adhering to the current collector foil 1a in the non-application area. This point will be described by taking the negative electrode 1 shown in FIG. 2 as an example. Usually, when the active material layer 1b is formed on the sheet-like current collector foil 1a, the current collector foil 1a is generally wound into a roll and stored. Then, in the subsequent compression step, the rolled current collector foil 1a is unwound again and conveyed to a pressure member (for example, a pair of rollers) 2 for pressing. That is, when the current collecting foil 1a wound into a roll shape is paid out in order from the start end portion 1b1 in the coating step, the current collector foil 1a is paid out in order from the end portion side. Therefore, the pressure member 2 is supplied from the end portion side, and is sequentially compressed from the end portion side of the current collector foil 1a toward the start end portion 1b1. At this time, if the pressing member 2 comes into contact with the raised portion of the starting end portion 1b1 of the active material layer 1b, and part of the active material layer 1b is chipped off and scattered, the starting end portion 1b1 of the active material layer 1b and the next active material layer 1b are separated from each other. An active material layer piece 1b2 is adhered onto the current collector foil 1a in the non-coated region between the end portion of the material layer 1b. In this way, the above-described problem occurs due to the active material layer piece 1b2 adhering to the current collector foil 1a in the non-applied area. At this time, the rate of defective adhesion of active material pieces to non-coated regions (defective rate) was about 39%. Even if the bulge of the starting end portion 1b1 was reduced to form a relatively gentle shape, this method resulted in about 17% of the non-coated regions having poor adhesion of the active material pieces.

On the other hand, in the present embodiment, when the active material layer 1b is formed on the sheet-like current collector foil 1a, the current collector foil 1a is wound into a roll shape, and then the current collector foil 1a is once rewound to perform a secondary roll. Form a roll (second roll). Then, the current collector foil 1 a is unwound from the second roll and supplied to the pressure member 2 . In this way, by adding the step of once rewinding the current collector foil 1a, it is possible to sequentially supply the current collector foil 1a to the pressure member 2 from the side of the start end 1b1 in the coating step and perform press working. In this case, as shown in FIG. 3, when the pressing member 2 comes into contact with the protruding portion of the starting end 1b1 of the active material layer 1b and part of the active material layer 1b is chipped off and scattered, the non-coated area is concentrated. The active material layer 1b2 adheres not to the electric foil 1a but to the active material layer 1b in the application area. That is, according to this method, the active material layer piece 1b2 does not adhere to the current collector foil 1a in the non-applied area, so that the above-described problems can be avoided. In addition, since the portions to which the active material pieces 1b2 adhere are subjected to press work after that, the active material layer pieces 1b2 adhere to the active material layer 1b in the application region, and the thickness of the active material layer 1b is locally reduced. Even if it increases slightly, it does not have much effect. As described above, in the present embodiment, the process of once rewinding the current collector foil 1a wound into a roll is added to prevent problems from occurring due to chipping of the active material layer 1b that is raised at the start end 1b1. can be suppressed. Similar effects can be obtained by performing similar processing on the positive electrode as well.

More specific examples of the method for manufacturing the electrode 1 of the present invention described above will now be described. In this example, a negative electrode 1 for an electrochemical device such as a secondary battery is manufactured. An example of processing conditions (condition 1) is as follows. The collector foil 1a is a copper foil with a thickness of 8 μm. The active material layer 1b generally contains an active material, a conductive agent (not shown), and a binder. In one example, the active material contains natural graphite, the conductive agent contains carbon black in which primary particles of about 30 nm are aggregated in a chain, and the binders are SBR (styrene-butadiene copolymer rubber) and CMC (carboxymethyl cellulose powder, Japan). Sunrose (registered trademark) MAC series manufactured by Paper Manufacturing Co., Ltd.). Their composition is 96.4 wt % active material, 0.4 wt % conductive agent, 2 wt % SBR, and 1 wt % CMC. The basis weight is 11.15 mg/cm ² and the density of the active material layer 1b is 1.55 g/cc.

In another example, electrodes were manufactured under the following processing conditions (Condition 2). The collector foil 1a is a copper foil with a thickness of 6 μm. It contains natural graphite and artificial graphite as an active material, carbon black in which primary particles of about 30 nm are aggregated in chain form as a conductive agent, and SBR and CMC as a binder. Their compositions are 77.1 wt% natural graphite, 19.3 wt% artificial graphite, 0.4 wt% conductive agent, 1.5 wt% SBR, and 1 wt% CMC. The basis weight is 12.70 mg/cm ² and the density of the active material layer 1b is 1.63 g/cc.

This time, an experiment was conducted to manufacture the negative electrode 1 based on the condition 2. An active material layer 1b was formed by intermittently applying slurry, which is a mixture (active material + conductive agent + binder), to both surfaces of a sheet-like collector foil (copper foil) 1a. On both sides of the current collector foil 1a, the formation positions of the active material layers 1b in the winding direction of the sheet-like current collector foil were substantially the same. The sheet-like collector foil 1a having the active material layers 1b formed on both sides thereof is wound into a roll (not shown).

Then, the current collector foil 1a wound into a roll is unwound and rewound to form a secondary roll. Then, the collector foil is unwound from the secondary roll and passed through the gap between the pair of rollers 2 shown in FIG. 1C. Since the gap between the pair of rollers 2 is kept constant, the active material layer 1b is compressed (static press). According to this method, the current collector foil 1a is wound into a roll, then rewound once, and then compressed while being fed out again. That is, the active material layer 1b is compressed from the same side (starting end side) as the starting end portion 1b1. As a result, as shown in FIG. 3, even if the active material layer 1b is chipped due to the roller 2 coming into contact with the raised portion of the starting end 1b1 of the active material layer 1b, the active material layer 1b is chipped, not on the current collector foil 1a in the non-coated area. Since the active material layer piece 1b2 adheres to the active material layer 1b in the application region and is subjected to pressing after the adhesion, there is almost no problem. Note that the feeding speed when feeding the current collector foil 1a from the secondary roll was 80 m/min, and the linear pressure applied from the roller 2 to the active material layer 1b was 0.36 t/cm. Thus, a negative electrode 1 having an active material layer 1b with a density of 1.65 g/cc was obtained. After compression, when the current collector foil 1a was cut into predetermined lengths, the rate (defective rate) of defective adhesion of the active material pieces to the non-applied regions was 1.8%.

In Condition 2, a mixture of natural graphite and artificial graphite is used as the active material, but only one of them may be included. The active material of the negative electrode 1 preferably contains graphite as a main component regardless of whether it is natural or artificial, and may be amorphous carbon such as hard carbon or soft carbon. Also, the active material may contain a metal or metal compound (eg, Si, SiOx, Sn, etc.) capable of intercalating and deintercalating lithium. The binder is not limited to SBR or the like, and may contain an acrylic resin containing acrylic acid or methacrylic acid as a unit structure, an amide resin, or an imide resin.

Next, as another embodiment, a method of dividing the compression process into two stages will be described. In the first embodiment, the current collector foil 1a wound into a roll after the coating process is once rewound and then subjected to the compression process. On the other hand, in the present embodiment, as shown in the negative electrode 1 in FIGS. 4A and 4B, the current collector foil 1a wound into a roll after the coating process is unwound and supplied to the pressure member 2, and press working is performed. conduct. However, the pressing at this stage is such that the pressure is so small that the active material layer 1b does not have a desired density (for example, a density of 1.55 g/cc). This first-stage compression is performed from the opposite side (terminal side) of the active material layer 1b to the starting end portion 1b1. However, since the pressing pressure is small, the active material layer 1b is not damaged, and the active material layer piece 1b2 does not adhere to the collector foil 1a in the non-applied area.

Then, the current collector foil 1a that has been subjected to the first-stage compression may or may not be wound into a roll again. In any case, as shown in FIGS. 4C to 4D, the current collector foil 1a in which the active material layer 1b has been somewhat compressed is supplied again to the pressure member 2, and the second stage of compression is performed. In the second-stage compression, the active material layer 1b is pressed from the starting end portion 1b1 side. Since the bulging of the starting end portion 1b1 is flattened to some extent in the first-stage compression, it is unlikely that the starting end portion 1b1 is chipped and the active material layer pieces 1b2 are scattered in the second-stage compression. In addition, even if the active material layer 1b is chipped by the compression in the second stage, the scattered active material layer pieces 1b2 adhere to the active material layer 1b in the applied area instead of the current collector foil 1a in the non-applied area. Since the press work is applied after adhesion, there is almost no problem. This second-stage compression gives the active material layer 1b a desired density (eg, 1.65 g/cc).

The graph shown in FIG. 5 shows the relationship between the linear pressure applied from the roller 2 to the active material layer 1b and the density of the compressed active material layer 1b in this example. Referring to this graph, it is preferable to set the linear pressure to about 0.25 t/cm in the first stage compression and to about 0.36 t/cm in the second stage compression. That is, in the first-stage compression, the linear pressure is about 69% of the linear pressure in the second-stage compression.

The simplest form of the invention will now be described. In the method of the present embodiment, a slurry containing an active material is intermittently applied onto a sheet-like current collector foil 1a, and the slurry-applied area and the non-applied area are separated from each other in the winding direction of the sheet-like current collector foil. A coating step of forming the active material layer 1b by winding the current collector foil along the winding direction while alternately forming the and a compression step. The compression step includes compressing the active material layer 1b from the formation start point (starting end) 1b1 in the formation direction of the active material layer 1b in the coating step toward the formation end point (terminal end). According to this method, even if the active material layer piece 1b2 scatters when the raised portion of the starting end portion 1b1 of the active material layer 1b is compressed, the active material in the applied area is not on the current collector foil 1a in the non-applied area. Since it adheres on layer 1b, no problem arises.

In the method for producing an electrode sheet of the present invention, a slurry containing an active material is intermittently applied to a sheet-shaped current collector foil, and a slurry-applied region and a non-applied region are formed into a sheet. A coating step of winding the current collector foil along the winding direction while alternately forming a shape of the current collector foil in the winding direction, and compressing the active material layer formed on the current collector foil in the thickness direction. and a compression step, and providing an electrode sheet with a low possibility of producing a defective product and a good yield in the case of producing an electrode for a secondary battery designed to have a high energy density by this method. becomes possible.

1 negative electrode (electrode sheet)
1a Current collector 1b Active material layer 1b1 Start end (formation start point)
1b2 active material layer piece 2 roller (pressure member)

Claims (13)

A method for manufacturing an electrode sheet in which an active material layer is formed on a sheet-like current collector foil,
A slurry containing an active material is intermittently applied onto the sheet-shaped current collector foil to alternately form areas coated with the slurry and non-coated areas in the winding direction of the sheet-shaped current collector foil. a coating step of winding the current collector foil along the winding direction; and a compression step of compressing the active material layer formed on the current collector foil in a thickness direction,
The compression step includes compressing the active material layer from the formation start point side toward the formation end point side in the formation direction of the active material layer in the coating step ,
After the coating step is completed, the current collecting foil having the active material layer formed thereon is wound into a roll, and then the current collecting foil having the active material layer formed thereon is rewound to form a secondary roll, A method for producing an electrode sheet for a lithium ion secondary battery, wherein the current collecting foil on which the active material layer is formed and unwound from the secondary roll is subjected to the compression step . In the compression step, the active material layer is compressed once,
In the application step, the slurry is sequentially applied along the winding direction of the sheet-like current collector foil, and in the compression step, the slurry is applied along the winding direction of the sheet-like current collector foil. 2. The method for manufacturing an electrode sheet for a lithium ion secondary battery according to claim 1, wherein the current collecting foil and the active material layer are sequentially compressed in the same direction. A method for manufacturing an electrode sheet in which an active material layer is formed on a sheet-like current collector foil,
A slurry containing an active material is intermittently applied onto the sheet-shaped current collector foil to alternately form areas coated with the slurry and non-coated areas in the winding direction of the sheet-shaped current collector foil. a coating step of winding the current collector foil along the winding direction; and a compression step of compressing the active material layer formed on the current collector foil in a thickness direction,
The compression step includes compressing the active material layer from the formation start point side toward the formation end point side in the formation direction of the active material layer in the coating step,
In the compression step, the active material layer is compressed in two stages, and in the application step, the slurry is sequentially applied along the winding direction of the sheet-like current collector foil, and the first In the step compression, the direction in which the current collector foil and the active material layer are sequentially compressed along the winding direction of the sheet-shaped current collector foil is opposite to the direction in which the sheet-shaped current collector foil is compressed in the coating step. The direction in which the slurry is sequentially applied along the winding direction of the electrical foil, and the current collector foil and the active material layer along the winding direction of the sheet-like current collector foil in the second stage compression. A method for producing an electrode sheet for a lithium ion secondary battery, wherein the direction of sequential compression is the same. 4. The method for producing an electrode sheet for a lithium ion secondary battery according to claim 3 , wherein in said first stage compression, said active material layer is compressed at a pressure that is 69% or less of the pressure in said second stage compression. A method for manufacturing an electrode sheet in which an active material layer is formed on a sheet-like current collector foil,
A slurry containing an active material is intermittently applied onto the sheet-shaped current collector foil to alternately form areas coated with the slurry and non-coated areas in the winding direction of the sheet-shaped current collector foil. a coating step of winding the current collector foil along the winding direction; and a compression step of compressing the active material layer formed on the current collector foil in a thickness direction,
The compression step includes compressing the active material layer from the formation start point side toward the formation end point side in the formation direction of the active material layer in the coating step,
The active material layers are formed on both sides of the sheet-like current collector foil, and the formation start points of the active material layers on both sides of the current collector foil are aligned in the winding direction of the sheet-like current collector foil. A method for manufacturing an electrode sheet for a lithium ion secondary battery, which has substantially the same position on both sides of the current collector foil. A method for manufacturing an electrode sheet in which an active material layer is formed on a sheet-like current collector foil,
A slurry containing an active material is intermittently applied onto the sheet-shaped current collector foil to alternately form areas coated with the slurry and non-coated areas in the winding direction of the sheet-shaped current collector foil. a coating step of winding the current collector foil along the winding direction; and a compression step of compressing the active material layer formed on the current collector foil in a thickness direction,
The compression step includes compressing the active material layer from the formation start point side toward the formation end point side in the formation direction of the active material layer in the coating step,
After the application step and before the compression step, the active material layer is intermittently formed from the starting point of forming the active material layer in the application step. The thickness of the active material layer formed within 4.4% of the length is 4% of the total length of each active material layer intermittently formed from the formation start point of the active material layer. A method for manufacturing an electrode sheet for a lithium ion secondary battery, which is thick in the range of 2% or more and 5% or less with respect to the thickness of the active material layer formed in the range of more than 4%. A method for manufacturing an electrode sheet in which an active material layer is formed on a sheet-like current collector foil,
A slurry containing an active material is intermittently applied onto the sheet-shaped current collector foil to alternately form areas coated with the slurry and non-coated areas in the winding direction of the sheet-shaped current collector foil. a coating step of winding the current collector foil along the winding direction; and a compression step of compressing the active material layer formed on the current collector foil in a thickness direction,
The compression step includes compressing the active material layer from the formation start point side toward the formation end point side in the formation direction of the active material layer in the coating step,
A method for producing an electrode sheet for a lithium ion secondary battery, wherein the density of the active material layer is set to 1.65 g/cm ³ or more in the compression step. A method for manufacturing an electrode sheet in which an active material layer is formed on a sheet-like current collector foil,
A slurry containing an active material is intermittently applied onto the sheet-shaped current collector foil to alternately form areas coated with the slurry and non-coated areas in the winding direction of the sheet-shaped current collector foil. a coating step of winding the current collector foil along the winding direction; and a compression step of compressing the active material layer formed on the current collector foil in a thickness direction,
The compression step includes compressing the active material layer from the formation start point side toward the formation end point side in the formation direction of the active material layer in the coating step,
The slurry contains at least the active material and an aqueous binder,
A method for producing an electrode sheet for a lithium ion secondary battery, wherein the content of the water-based binder is 0.01 parts by mass or more and 3 parts by mass or less in the slurry containing the active material. 2. The linear pressure applied to the active material layer and the current collector foil in the central portion of the application region where the slurry is applied in the compressing step is 0.1 t/cm or more and 0.5 t/cm or less. 9. The method for producing the electrode sheet for a lithium ion secondary battery according to any one of 8 . The lithium ion secondary battery according to any one of claims 1 to 9 , wherein the compression step is performed by inserting the current collector foil on which the active material layer is formed between a pair of rollers. A method for manufacturing an electrode sheet. The manufacturing method of the electrode sheet for lithium ion secondary batteries as described in any one of Claims 1-10 which manufactures the negative electrode sheet of a lithium ion secondary battery. The method for producing an electrode sheet for a lithium ion secondary battery according to any one of claims 1 to 11 , wherein said slurry contains at least graphite as said active material. 13. The method of manufacturing an electrode sheet for a lithium ion secondary battery according to claim 12 , wherein said slurry contains at least artificial graphite as said active material.

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