JP2015187961A - Manufacturing apparatus of power storage device and manufacturing method of power storage device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the manufacturing cost of a power storage device such as a lithium ion battery.SOLUTION: A knife-over-roll coater RC included in a manufacturing apparatus of electrode plate has a knife roll NRL arranged on the surface side of a current collector foil PEP traveling in a first direction, and a back roll BRL arranged on the back side of the current collector foil PEP oppositely to the knife roll NRL. Furthermore, the knife-over-roll coater RC has a first liquid supply section LS1, a second liquid supply section LS2, and a third liquid supply section LS3 arranged, in order, in a second direction perpendicular to the first direction on the surface of the current collector foil PEP. The first liquid supply section LS1 supplies a solution containing an insulating material (a first insulator IF1) to the surface of the current collector foil PEP, the second liquid supply section LS2 supplies an electrode material (a positive electrode material PAS) to the surface of the current collector foil PEP, and the third liquid supply section LS3 supplies a solution containing an insulating material (the first insulator IF1) to the surface of the current collector foil PEP.

Description

  The present invention relates to a manufacturing apparatus and a manufacturing method for an electricity storage device, and can be suitably used for, for example, a step of applying an electrode material for an electricity storage device.

  As a background art of this technical field, there is JP-A-2003-045491 (Patent Document 1). This publication includes a positive electrode sheet delivery mechanism, a positive electrode material coating mechanism, a positive electrode forming heating mechanism, an electrolysis and insulating material coating mechanism, an electrolysis and insulator forming heating mechanism, and a negative electrode sheet. Secondary equipped with a state material delivery mechanism, a negative electrode material coating mechanism, a negative electrode formation heating mechanism, an electrolysis / insulation material coating mechanism, an electrolysis / insulator formation heating mechanism, and a winding mechanism A battery manufacturing apparatus is described. The winding mechanism is formed by laminating a positive electrode sheet material to which a positive electrode material and electrolysis and an insulating material are fixed, and a negative electrode sheet material to which a negative electrode material and an electrolysis and insulating material are fixed, to form a predetermined shape. It is a rotating mechanism.

JP 2003-054991 A

  For example, a lithium ion battery representing an electricity storage device includes a positive electrode plate coated with a positive electrode material containing a positive electrode active material on the surface of a current collector metal foil (hereinafter referred to as a current collector foil), and a current collector foil. A negative electrode plate containing a negative electrode active material is applied to the surface of the electrode, and a dried negative electrode plate and a separator for preventing contact between the positive electrode plate and the negative electrode plate are provided. In the lithium ion battery, the electrode winding body is inserted into the battery can, and an electrolyte is injected into the battery can. That is, in the lithium ion battery, the positive electrode plate and the negative electrode plate are wound in a cross-sectional spiral shape via the separator so that the electrode winding body is formed so as not to contact directly.

  By the way, when a positive electrode material or a negative electrode material is applied to the surface of the current collector foil, both side portions (both end portions) of the applied portion swell like a mountain shape. The raised portion is removed before the electrode winding body is formed. The raised portions of the positive electrode material and the negative electrode material to be removed are included in the manufacturing cost of the lithium ion battery as material costs. For this reason, removing the raised portions of the positive electrode material and the negative electrode material is one factor that makes it difficult to reduce the manufacturing cost of the lithium ion battery.

  Other problems and novel features will become apparent from the description of the specification and the accompanying drawings.

  An apparatus for manufacturing an electricity storage device according to an embodiment includes a knife roll disposed on a front surface side of a current collector foil traveling in a first direction, and a back roll disposed on a rear surface side of the current collector foil so as to face the knife roll. And a first liquid supply part, a second liquid supply part, and a third liquid supply part that are sequentially arranged in a second direction orthogonal to the first direction and the surface of the current collector foil. Equipped with a coating machine. The first liquid supply unit includes a first solution containing an insulating material, the second liquid supply unit includes an electrode material, and the third liquid supply unit includes a second solution containing an insulating material between the knife roll and the back roll. To the surface of the current collector foil.

  In one embodiment, a method of manufacturing an electricity storage device includes applying a slurry-like electrode material containing an active material to the surface of a current collector foil that travels in a first direction. Applying a solution containing an insulating material to the surface of the current collector foil on both sides of the electrode material in the second direction orthogonal to each other, and applying a slurry-like insulating material containing an insulating material to the upper surface of the electrode material and the solution The process of carrying out.

  According to one embodiment, the manufacturing cost of an electricity storage device such as a lithium ion battery can be reduced.

It is sectional drawing which shows the internal structure of the lithium ion battery in this Embodiment. It is the schematic of the manufacturing apparatus of the electrode plate of the lithium ion battery in this Embodiment. It is a figure explaining the coating machine with which the manufacturing apparatus of the electrode plate of the lithium ion battery in this Embodiment is equipped. (A) is a top view of the coating machine, and (b) is a cross-sectional view of the coating machine (a cross-sectional view taken along line AA of FIG. 1 (a)). It is sectional drawing which shows typically the positive electrode material apply | coated to the surface of the current collection foil in this Embodiment. It is sectional drawing which shows typically the coating film which laminated | stacked the positive electrode material apply | coated on the surface of the current collection foil in this Embodiment, and the insulating material used as the separator apply | coated on it. It is process drawing which put together the specific manufacturing process of the lithium ion battery in this Embodiment. It is a figure explaining the coating machine with which the manufacturing apparatus of the electrode plate of the lithium ion battery which the present inventors examined prior to this invention is equipped. (A) is a top view of the coating machine, (b) is a cross-sectional view of the coating machine (cross-sectional view taken along line BB in FIG. 1 (a)). It is sectional drawing which shows typically the coating film which laminated | stacked the electrode material apply | coated on the surface of the current collector foil which the present inventors examined prior to this invention, and the insulating material used as the separator apply | coated on it. .

  In the following embodiments, when referring to the number of elements, etc. (including the number, numerical value, quantity, range, etc.), unless otherwise specified, the principle is clearly limited to a specific number, etc. The number is not limited to the specific number, and may be a specific number or more.

  Further, in the following embodiments, the constituent elements (including element steps and the like) are not necessarily indispensable unless otherwise specified and apparently essential in principle. Needless to say.

  In addition, when referring to “consisting of A”, “consisting of A”, “having A”, and “including A”, other elements are excluded unless specifically indicated that only that element is included. It goes without saying that it is not what you do. Similarly, in the following embodiments, when referring to the shapes, positional relationships, etc. of the components, etc., the shapes are substantially the same unless otherwise specified, or otherwise apparent in principle. And the like are included. The same applies to the above numerical values and ranges.

  Further, in the drawings used in the following embodiments, hatching is given to make the drawings easy to see even if they are plan views. In all the drawings for explaining the following embodiments, parts having the same function are denoted by the same reference numerals, and repeated explanation thereof is omitted. Hereinafter, embodiments will be described in detail with reference to the drawings.

  In the following description, the positive electrode material and the negative electrode material are collectively referred to as “electrode material”, the film made of the positive electrode material after the drying process is called “positive electrode film”, and the film made of the negative electrode material after the drying process is called “negative electrode film”. The positive electrode film and the negative electrode film are collectively referred to as “electrode film”. Moreover, in the following description, the positive electrode material, the negative electrode material, and the insulating material before the drying step are substances having fluidity including a liquid such as a binder solution and an organic solvent. In the following description, the current collector foil on which the positive electrode film is formed is referred to as “positive electrode plate (also referred to as positive electrode sheet)”, and the current collector foil on which the negative electrode film is formed is referred to as “negative electrode plate (also referred to as negative electrode sheet)”. The positive electrode plate and the negative electrode plate are collectively referred to as an “electrode plate (also referred to as an electrode sheet)”. In the following description, “the surface of the current collector foil” refers to only the front surface, not the entire surface including the front surface and the back surface of the current collector foil. In the following description, a direction in which the current collector foil travels is referred to as a “first direction”, and a direction orthogonal to the first direction on the surface of the current collector foil is referred to as a “second direction”.

(Production apparatus and production method of lithium ion battery which the present inventors have conducted a comparative study)
First, since it seems that the manufacturing apparatus and manufacturing method of a lithium ion battery in this Embodiment will become clearer, as a comparative example, the lithium ion battery before the present invention was examined by the present inventors. A manufacturing apparatus and a manufacturing method will be described.

  FIG. 7 is a diagram for explaining a coating machine provided in an apparatus for manufacturing an electrode plate of a lithium ion battery examined by the present inventors prior to the present invention. FIG. 7A is a top view of the coating machine, and FIG. 7B is a cross-sectional view of the coating machine (a cross-sectional view taken along line BB in FIG. 7A).

  As shown in FIGS. 7A and 7B, a roll knife coater RC0 that is a coating machine includes a back roll (also referred to as a backup roll) BRL, a knife roll NRL, and a liquid supply unit (liquid retainer, dam). It is also composed of LS.

  The back roll BRL and the knife roll NRL are rolls extending in a first direction in which the current collector foil PEP travels and a second direction orthogonal to the surface of the current collector foil PEP. The back roll BRL and the knife roll NRL are current collectors. Opposite the foil PEP. The back roll BRL rotates in the direction in which the current collector foil PEP travels in the first direction, but the knife roll NRL is fixed.

  The back roll BRL and the current collector foil PEP are in contact with each other, but the knife roll NRL and the current collector foil PEP are not in contact with each other, so that there is a gap between the knife roll NRL and the current collector foil PEP. BRL and knife roll NRL are installed. That is, the thickness of the electrode material EM is adjusted by the gap between the back roll BRL and the knife roll NRL.

  The liquid supply unit LS is installed on the upstream side of the position where the back roll BRL and the knife roll NRL face each other. Walls WA are formed on both sides of the liquid supply part LS in the second direction, and an electrode material EM containing an active material is stored in the liquid supply part LS. When the current collector foil PEP travels in the first direction, the electrode material EM is drawn from the liquid supply unit LS to a position where the back roll BRL and the knife roll NRL face each other. Thereby, the electrode material EM is applied to the surface of the current collector foil PEP traveling in the first direction.

  FIG. 8 schematically shows a coating film obtained by laminating an electrode material applied to the surface of a current collector foil investigated by the inventors prior to the present invention and an insulating material to be a separator applied thereon. It is sectional drawing.

  As shown in FIG. 8, the electrode material EM is applied to the surface of the current collector foil PEP running in the first direction to form the electrode material EM having a substantially constant thickness. However, both side portions (both ends) in the second direction orthogonal to the first direction of the electrode material EM and the surface of the current collector foil PEP are raised like a mountain shape. The raised portion of the electrode material EM is caused by the viscosity and surface tension of the electrode material EM. The difference between the apex of the raised portion of the electrode material EM and the flat portion of the electrode material EM is, for example, about several μm, but the insulating material that becomes a separator on the electrode material EM while leaving the raised portion of the electrode material EM When IF is applied, there is a problem that the insulating material IF flows downward from the top of the raised portion of the electrode material EM, and the raised portion of the electrode material EM is exposed.

  The above problem similarly occurs in the positive electrode material and the negative electrode material. Then, when the electrode winding body is formed using the positive electrode plate that leaves the raised portion of the positive electrode material and the negative electrode plate that leaves the raised portion of the negative electrode material, the raised portions overlap and a gap is generated, It becomes difficult to insert the positive electrode plate and the negative electrode plate into the battery can without any gap.

  Therefore, in order to insert the positive electrode plate and the negative electrode plate into the battery can without any gaps, the positive electrode plate and the negative electrode plate are cut into a predetermined strip size, and the raised portions generated on both sides of the positive electrode material and the negative electrode material are formed. After removal, an electrode winding body is formed. That is, the electrode winding body uses a positive electrode plate in which the positive electrode material is uniformly applied to the surface of the current collector foil PEP and a negative electrode plate in which the negative electrode material is uniformly applied to the surface of the current collector foil PEP. ing.

  However, in order to cut the positive electrode plate and the negative electrode plate into a predetermined band size and discard the bulged portion of the positive electrode material and the negative electrode material, the positive electrode material or the negative electrode material applied to the surface of the current collector foil PEP in the application process Not all can be used effectively. Moreover, the bulging part of the discarded positive electrode material and negative electrode material is also included in the manufacturing cost of the lithium ion battery. For this reason, discarding the rising portions of the positive electrode material and the negative electrode material is one of the causes that make it difficult to reduce the manufacturing cost of the lithium ion battery. In addition, not only the electrode winding type lithium ion battery but also a laminate type lithium ion battery has the same problem.

(Embodiment)
In this embodiment, a lithium ion battery is exemplified as a secondary battery that is an electricity storage device, and a manufacturing apparatus and a manufacturing method thereof will be described. The lithium ion battery is a kind of non-aqueous electrolyte secondary battery, and is a secondary battery in which lithium ions in the electrolyte bear electric conduction.

For example, a lithium-containing composite oxide is used for the positive electrode, and a carbonaceous material is used for the negative electrode. As the electrolyte, for example, an electrolytic solution made of an organic solvent such as ethylene carbonate or a lithium salt such as lithium hexafluorophosphate (LiPF ₆ ) is used. In a lithium ion battery, lithium ions exit from the positive electrode during charging and enter the negative electrode, and conversely during discharge, lithium ions exit from the negative electrode and enter the positive electrode.

≪Lithium-ion battery structure≫
The internal structure of the lithium ion battery in this embodiment will be described with reference to FIG. FIG. 1 is a cross-sectional view showing the internal structure of the lithium ion battery in the present embodiment.

  As shown in FIG. 1, a lithium ion battery includes, for example, a positive electrode plate PE in which a positive electrode film (positive electrode film) is formed on the surface of a current collector foil (eg, Al (aluminum) foil), and a current collector foil (eg, Cu A negative electrode plate NE on which a negative electrode film (negative electrode film) is formed on the surface of (copper) foil. And the electrode winding body which wound separator SP, such as a polymer film which prevents contact with positive electrode plate PE, negative electrode plate NE, and positive electrode plate PE and negative electrode plate NE, is a cylindrical battery can (exterior can). , Also referred to as a container). That is, in the lithium ion battery, a positive electrode plate PE in which a positive electrode film is formed on the surface of the current collector foil and a negative electrode plate NE in which a negative electrode film is formed on the surface of the current collector foil are formed in a band shape, and the positive electrode formed in the band shape The plate PE and the negative electrode plate NE are wound in a cross-sectional spiral shape via the separator SP so that the positive electrode film and the negative electrode film are not in direct contact with each other, thereby forming an electrode winding body.

  In the lithium ion battery, the electrode winding body is inserted into the battery can CO, and the battery can CO is filled with an electrolyte. One end of the battery can CO is sealed with a positive terminal PET, and the other end is sealed with a negative terminal NET. The positive electrode plate PE is electrically connected to a positive electrode terminal PET having a gas discharge structure via a positive electrode lead PEL made of a metal film, and the negative electrode plate NE is connected to a negative electrode lead (not shown) made of a metal film. Are electrically connected to the negative terminal NET.

≪Method of manufacturing electrode sheet for lithium ion battery≫
The manufacturing method of the electrode plate of the lithium ion battery in this Embodiment is demonstrated using FIGS. FIG. 2 is a schematic diagram of an apparatus for manufacturing an electrode plate of a lithium ion battery in the present embodiment. 3A and 3B are diagrams for explaining a coating machine provided in an apparatus for manufacturing an electrode plate of a lithium ion battery according to the present embodiment. FIG. 3A is a top view of the coating machine, and FIG. It is sectional drawing (AA sectional drawing of the AA line of the figure (a)) of a construction machine. FIG. 4 is a cross-sectional view schematically showing the positive electrode material applied to the surface of the current collector foil in the present embodiment. FIG. 5 is a cross-sectional view schematically showing a coating film obtained by laminating a positive electrode material applied to the surface of the current collector foil in the present embodiment and an insulating material to be a separator applied thereon.

  In the present embodiment, a method for producing a positive electrode film formed in one row on the surface of a current collector foil traveling in the first direction is exemplified. In the present embodiment, a method for manufacturing one side of the positive electrode plate is illustrated, but the method for manufacturing one side of the negative electrode plate is also the same.

  As shown in FIG. 2, in the manufacturing apparatus M1 for an electrode plate of a lithium ion battery, a current collector foil (also referred to as a metal foil, an electrode plate, a substrate, a substrate, a sheet-like material) PEP is fed from an unwinding roll SL1. It is fed out and conveyed to the take-up roll SL2 by a plurality of rollers. A roll knife coater RC, a slit coater (also referred to as a slit die coater) DC and a drying chamber (also referred to as a drying furnace, a drying mechanism, etc.) DRY are sequentially installed from the unwinding roll SL1 to the winding roll SL2. .

1. First application step (positive electrode material and first insulating material application step)
First, as shown in FIG. 2, the positive electrode material PAS and the first insulating material IF1 are simultaneously applied to the surface of the current collector foil PEP fed from the unwinding roll SL1 and traveling in the first direction using the roll knife coater RC. Applied.

  As shown in FIGS. 3A and 3B, a roll knife coater RC that is a coating machine includes a back roll BRL, a knife roll NRL, a first liquid supply unit LS1, and a second liquid supply unit LS2. And the third liquid supply unit LS3.

  The back roll BRL and the knife roll NRL are opposed to each other with the current collector foil PEP traveling in the first direction interposed therebetween. The length in the second direction orthogonal to the first direction of the back roll BRL and the surface of the current collector foil PEP is longer than the width in the second direction of the current collector foil PEP, and the cross section along the first direction of the back roll BRL is It is circular. Further, the back roll BRL has a rotating function, and rotates so that the current collector foil PEP travels in the first direction around the center of the cross section along the first direction. Similar to the back roll BRL, the length of the knife roll NRL in the second direction is longer than the width of the current collector foil PEP in the second direction. However, the cross section along the first direction of the knife roll NRL is substantially circular. However, unlike the back roll BRL, the knife roll NRL adjusts the thicknesses of the positive electrode material PAS and the first insulating material IF1, so that The part to be scraped off is provided along the second direction. The knife roll NRL is fixed.

  The back roll BRL and the current collector foil PEP are in contact with each other, but the knife roll NRL and the current collector foil PEP are not in contact with each other, so that there is a gap between the knife roll NRL and the current collector foil PEP. BRL and knife roll NRL are installed. That is, the thicknesses of the positive electrode material PAS and the first insulating material IF1 are adjusted by the gap between the back roll BRL and the knife roll NRL. The distance between the back roll BRL and the knife roll NRL is, for example, about 50 μm to 200 μm.

  The first liquid supply unit LS1, the second liquid supply unit LS2, and the third liquid supply unit LS3 are arranged side by side in the second direction on the upstream side of the position where the back roll BRL and the knife roll NRL face each other. Yes. In other words, the first liquid supply unit LS1 and the third liquid supply unit LS3 are installed with the second liquid supply unit LS2 sandwiched in the second direction.

  The first liquid supply unit LS1 and the third liquid supply unit LS3 are dams that store the first insulating material IF1, and the second liquid supply unit LS2 is a dam that stores the positive electrode material PAS. The positive electrode material PAS has a high viscosity obtained by kneading and dispersing a positive electrode active material powder capable of releasing and occluding lithium ions by charge / discharge and a conductive auxiliary powder with a binder and a solvent for binding these powders. This is a slurry liquid. The first insulating material IF1 is a solution containing an insulating substance. The first insulating material IF1 may be made of the same material as the second insulating material IF2 serving as a separator described later.

  When the current collector foil PEP travels in the first direction, the current collector foil PEP passing through the back roll BRL draws the positive electrode material PAS from the second liquid supply unit LS2 to a position where the back roll BRL and the knife roll NRL face each other. The first insulating material IF1 is drawn out from the first liquid supply part LS1 and the third liquid supply part LS3, respectively. Then, the excess positive electrode material PAS and the first insulating material IF1 exceeding the target amount are scraped off by the knife roll NRL. Thereby, the positive electrode material PAS is applied to the surface of the current collector foil PEP traveling in the first direction, and at the same time, the positive electrode material PAS is sandwiched in the second direction on the surface of the current collector foil PEP traveling in the first direction. In addition, the first insulating material IF1 is applied to both sides of the positive electrode material PAS in the second direction. In other words, the positive electrode material PAS is applied to the surface of the current collector foil PEP traveling in the first direction, and at the same time, the first insulating material IF1 is in contact with both side surfaces of the positive electrode material PAS in the second direction, The positive electrode material PAS is applied to the surface of the current collector foil PEP outside in the second direction.

  Walls WA are provided on both sides in the second direction of each of the first liquid supply unit LS1, the second liquid supply unit LS2, and the third liquid supply unit LS3, and the first insulating material of the first liquid supply unit LS1 is provided. IF1 and the positive electrode material PAS of the second liquid supply unit LS2, and the first insulating material IF1 of the third liquid supply unit LS3 and the positive electrode material PAS of the second liquid supply unit LS2 are partitioned so as not to mix.

  By the way, since the positive electrode material PAS is a slurry liquid, it spreads when passing through the gap between the back roll BRL and the knife roll NRL, and the width in the second direction of the positive electrode material PAS applied to the surface of the current collector foil PEP. W1 is larger than the width W2 in the second direction of the liquid supply port of the second liquid supply unit. The spread of the positive electrode material PAS when passing through the gap between the back roll BRL and the knife roll NRL depends on the gap gap between the back roll BRL and the knife roll NRL, the viscosity of the positive electrode material PAS, the conveying speed of the current collector foil PEP, etc. Because it changes, it is not a constant spread.

  Therefore, if the width of the wall WA provided between the first liquid supply part LS1 and the second liquid supply part LS2 and between the third liquid supply part LS3 and the second liquid supply part LS2 is too thin, the back When the positive electrode material PAS and the first insulating material IF1 pass through the gap between the roll BRL and the knife roll NRL, they are mixed together. On the other hand, if the width of the wall WA provided between the first liquid supply part LS1 and the second liquid supply part LS2 and between the third liquid supply part LS3 and the second liquid supply part LS2 is too thick, the back When the positive electrode material PAS and the first insulating material IF1 pass through the gap between the roll BRL and the knife roll NRL, they do not come into contact with each other, and both side portions (both ends) of the positive electrode material PAS rise like a mountain shape. End up.

  Therefore, it is preferable that the wall WA formed on both sides in the second direction of each of the first liquid supply unit LS1, the second liquid supply unit LS2, and the third liquid supply unit LS3 has an optimum width. Therefore, the roll knife coater RC is provided with a mechanism capable of adjusting the width of the wall WA according to the coating conditions. By adjusting the width of the wall WA, the positive electrode material PAS and the first insulating material IF1 are provided. The positive electrode material PAS and the first insulating material IF1 are in contact with each other without being mixed.

  FIG. 4 shows a cross-sectional view in the second direction of the current collector foil PEP coated with the positive electrode material PAS and the first insulating material IF1.

  As shown in FIG. 4, the thickness of the positive electrode material PAS applied to the surface of the current collector foil PEP is substantially constant. On the other hand, the first insulating material IF1 coated on the surface of the current collector foil PEP so as to sandwich the positive electrode material PAS in the second direction is raised like a mountain. This raised portion is caused by the viscosity and surface tension of the first insulating material IF1. However, the region to which the first insulating material IF1 is applied is a region that is cut after the positive electrode plate is completed, and the raised portion is discarded later.

2. Second coating process (second insulating material (separator material) coating process)
Next, as shown in FIG. 2, the slurry-like second insulating material IF2 supplied from the slit coater DC is applied to the surface of the current collector foil PEP traveling in the first direction.

  The second insulating material IF2 is applied to the upper surfaces of the first insulating material IF1 and the positive electrode material PAS along the first direction in which the current collector foil PEP travels. The thickness of the second insulating material IF2 is, for example, about 10 μm to 40 μm. The thickness of the second insulating material IF2 can be adjusted, for example, by adjusting the height of the die of the slit die coater DC and feeding the second insulating material IF2.

  FIG. 5 shows a cross-sectional view in the second direction of the current collector foil PEP in which the second insulating material IF2 is applied to the upper surfaces of the positive electrode material PAS and the first insulating material IF1.

  As shown in FIG. 5, since the upper surface of the positive electrode material PAS applied to the surface of the current collector foil PEP is a substantially flat surface, the thickness of the second insulating material IF2 applied to the upper surface of the positive electrode material PAS is It becomes almost constant. In contrast, the first insulating material IF1 coated on the surface of the current collector foil PEP so as to sandwich the positive electrode material PAS in the second direction has a chevron-like raised portion. For this reason, the second insulating material IF2 applied to the upper surface of the raised portion of the first insulating material IF1 becomes thinner than the thickness of the second insulating material IF2 applied to the upper surface of the flat portion of the first insulating material IF1, The raised portion of the first insulating material IF1 is exposed. However, the region to which the first insulating material IF1 is applied is a region that is cut after the positive electrode plate is completed, and since this raised portion is discarded later, there is no problem even if the first insulating material IF1 is raised. .

  Moreover, the price of the insulating material contained in the first insulating material IF1 that is cut and the raised portion is discarded is lower than the price of the positive electrode active material contained in the positive electrode material PAS. Therefore, it is possible to reduce the manufacturing cost of the lithium ion battery by discarding a part of the first insulating material IF1 instead of discarding a part of the positive electrode material PAS.

3. Next, as shown in FIG. 2, by passing through the drying chamber DRY, the positive electrode material PAS and the first insulating material IF1 applied to the surface of the current collector foil PEP, and the second insulating material applied to the upper surface thereof The entire coating film laminated with the material IF2 is dried, and the current collector foil PEP, on which the positive electrode film made of the positive electrode material PAS and the separator made of the second insulating material IF2 are formed, is taken up by the take-up roll SL2. .

≪Specific manufacturing process of lithium-ion battery≫
A specific manufacturing process of the lithium ion battery according to the present embodiment will be described with reference to FIG. FIG. 6 is a process diagram summarizing a specific manufacturing process of the lithium ion battery in the present embodiment.

  As shown in FIG. 6, the manufacturing process of a lithium ion battery includes a positive electrode plate manufacturing process, a negative electrode plate manufacturing process, a battery cell assembly process, and a battery module assembly process.

  In the positive electrode plate manufacturing process, first, a positive electrode material containing a slurry-like positive electrode active material is applied to the surface of a film-like current collector foil that runs in the first direction, and at the same time, a film-like shape that runs in the first direction. A first insulating material containing a slurry-like insulating material is applied to the surface of the current collector foil so that the positive electrode material is sandwiched in a second direction perpendicular to the first direction and the surface of the current collector foil (the positive electrode material and the first material). 1 insulating material application process). The positive electrode material and the first insulating material are produced by mixing and preparing various materials as raw materials. For example, as shown in FIG. 4, the first insulating material has a mountain-shaped raised portion, but the thickness of the positive electrode material is substantially constant.

  Subsequently, a slurry-like second insulating material serving as a separator is applied to the upper surface of the positive electrode material and the first insulating material applied to the surface of the film-like current collector foil (separator material applying step). The second insulating material is produced by mixing and mixing various materials as raw materials. For example, as shown in FIG. 5, the thickness of the second insulating material is reduced at the raised portion of the first insulating material, and the upper surface of the first insulating material may be exposed, but the upper surface of the positive electrode material is uniform. The second insulating material having a sufficient thickness is applied, and the upper surface of the first insulating material is not exposed.

  Then, after drying the whole coating film which laminated | stacked the positive electrode material and 1st insulating material which were apply | coated to the surface of film-form current collection foil, and the 2nd insulating material apply | coated to these upper surfaces (drying process) The current collector foil on which the coating film is formed is subjected to processing such as compression and cutting (processing step). Thus, a film in which a positive electrode film made of a positive electrode material and an insulating film made of a first insulating material and a separator made of a second insulating material formed on the upper surface of the film-like current collector foil are laminated. A positive electrode plate is produced. Here, when cutting the current collector foil on which the coating film is formed, the region where the insulating film made of the first insulating material is formed is cut, and the raised portion of the insulating film (for example, shown in FIG. The raised portion of the first insulating material IF1 is removed. As a result, a positive electrode plate having a uniform thickness composed of the positive electrode plate and the insulating film (part of the insulating film remaining without being removed) and the separator formed on the upper surface thereof is manufactured.

  On the other hand, in the negative electrode plate manufacturing process, various materials used as raw materials are different from those of the positive electrode plate manufacturing process, but the procedure until the negative electrode plate is manufactured is the same as the positive electrode plate manufacturing process. First, a negative electrode material containing a slurry-like negative electrode active material is applied to the surface of a film-like current collector foil that runs in the first direction, and simultaneously, on the surface of the film-like current collector foil that runs in the first direction. The first insulating material containing the slurry-like insulating material is applied so that the negative electrode material is sandwiched between the first direction and the second direction orthogonal to the surface of the current collector foil (negative electrode material and first insulating material application step). . The negative electrode material and the first insulating material are produced by mixing and preparing various materials as raw materials. For example, as shown in FIG. 4, the first insulating material has a mountain-shaped raised portion, but the thickness of the negative electrode material is substantially constant.

  Subsequently, a slurry-like second insulating material serving as a separator is applied to the upper surface of the negative electrode material and the first insulating material applied to the surface of the film-like current collector foil (separator material applying step). The second insulating material is produced by mixing and mixing various materials as raw materials. For example, as shown in FIG. 5, the thickness of the second insulating material is reduced at the raised portion of the first insulating material and the upper surface of the first insulating material may be exposed, but the upper surface of the negative electrode material is uniform. The second insulating material having a sufficient thickness is applied, and the upper surface of the first insulating material is not exposed.

  Then, after drying the whole coating film which laminated | stacked the negative electrode material and 1st insulating material which were apply | coated on the surface of film-form current collection foil, and the 2nd insulating material apply | coated to these upper surfaces (drying process) The current collector foil on which the coating film is formed is subjected to processing such as compression and cutting (processing step). Thus, a film in which a negative electrode film made of a negative electrode material and an insulating film made of a first insulating material and a separator made of a second insulating material formed on the upper surface of the film-like current collector foil are laminated. A negative electrode plate is produced. Here, when cutting the current collector foil on which the coating film is formed, the region where the insulating film made of the first insulating material is formed is cut, and the raised portion of the insulating film (for example, shown in FIG. The raised portion of the first insulating material IF1 is removed. As a result, a negative electrode plate having a uniform thickness composed of the negative electrode plate and the insulating film (part of the insulating film remaining without being removed) and the separator formed on the upper surface thereof is manufactured.

  Next, in the battery cell assembly process, a positive electrode having a size necessary for the battery cell is cut out from the film-like positive electrode plate, and a negative electrode having a size necessary for the battery cell is cut out from the film-like negative electrode plate. Are wound and stacked together to form an electrode winding body (a group of positive and negative electrode pairs that are wound together) (winding step). Since the separator is already formed on the positive electrode plate and the negative electrode plate, in this winding process, it is not necessary to sandwich the separator between the positive electrode and the negative electrode, and the manufacturing cost of the lithium ion battery is reduced. can do. Moreover, since the thickness of a positive electrode plate and a negative electrode plate is substantially uniform, a positive electrode and a negative electrode can be tied together without gap.

  Next, the electrode winding body is assembled and welded (welding / assembly process). Subsequently, the welded electrode winding body is placed in the battery can into which the electrolytic solution has been injected (liquid injection process), and then the battery can is completely sealed (sealing process) to produce a battery cell. In the electrode winding body, since the positive electrode and the negative electrode are wound together without any gap, the electrode winding body can be easily inserted into the battery can without any gap.

  Next, the manufactured battery cell is repeatedly charged / discharged (charging / discharging process), and inspections regarding the performance and reliability of the battery cell (for example, the capacity and voltage of the battery cell, and the current during charging or discharging of the battery cell) And inspection of voltage etc.) (single cell inspection process). Thereby, a battery cell is completed and a battery cell assembly process is complete | finished.

  Next, in the battery module assembly process, a battery module is configured by combining a plurality of battery cells in series, and a battery system is configured by connecting a controller for charge / discharge control (module assembly process). Subsequently, an inspection regarding performance and reliability of the assembled battery module (for example, inspection of capacity and voltage of the battery module and current and voltage at the time of charging or discharging the battery module) is performed (module inspection step). Thereby, a battery module is completed and a battery module assembly process is complete | finished.

≪Each material of lithium ion battery≫
Each material which comprises the lithium ion battery in this Embodiment, and each material used when manufacturing a lithium ion battery is demonstrated in detail.

  As the positive electrode active material used in this embodiment, for example, a lithium-containing composite oxide having a spinel structure containing lithium cobaltate or Mn (manganese) can be used. As the positive electrode active material, a composite oxide containing Ni (nickel), Co (cobalt), and Mn (manganese), or an olivine type compound represented by olivine type iron phosphate can be used. However, the material used for the positive electrode active material is not limited to these.

Since a lithium-containing composite oxide having a spinel structure containing Mn (manganese) is excellent in thermal stability, a lithium ion battery with high safety can be formed by forming a positive electrode sheet containing this. . Further, as the positive electrode active material, only a lithium-containing composite oxide having a spinel structure containing Mn (manganese) may be used, but other positive electrode active materials may be used in combination. Examples of such other positive electrode active materials include olivine type represented by Li _{1 + x} MO ₂ (−0.1 <x <0.1, M: Co, Ni, Mn, Al, Mg, Zr, Ti, etc.), for example. Compound etc. are mentioned. Further, specific examples of the lithium-containing transition metal oxide having a layered structure include LiCoO ₂ or LiNi _1-x Co _xy Al _y O ₂ (0.1 ≦ x ≦ 0.3, 0.01 ≦ y ≦ 0). .2) can be used. Further, the lithium-containing transition metal oxide having a layered structure includes an oxide containing at least Ni (nickel), Co (cobalt), and Mn (manganese) (LiMn _1/3 Ni _1/3 Co _1/3 O ₂ , LiMn _5/12 Ni _5/12 Co _1/6 O ₂ , LiNi _3/5 Mn _1/5 Co _1/5 O _2, etc.) can be used.

  As the negative electrode active material used in the present embodiment, for example, a graphite material such as natural graphite (flaky graphite), artificial graphite, or expanded graphite can be used. Further, as the negative electrode active material, an easily graphitizable carbonaceous material such as coke obtained by firing pitch can be used. Further, a non-graphitizable carbonaceous material such as amorphous carbon obtained by low-temperature firing of furfuryl alcohol resin (PFA), polyparaphenylene (PPP), phenol resin, or the like may be used as the negative electrode active material. Good. In addition to the carbon material, Li (lithium) or a lithium-containing compound can also be used as the negative electrode active material.

  Examples of the lithium-containing compound include a lithium alloy such as Li—Al, or an alloy containing an element capable of alloying Si (silicon) or Sn (tin) with Li (lithium). Furthermore, an oxide-based material such as Sn oxide or Si oxide can also be used.

  The conductive auxiliary agent used in the present embodiment is used as an electronic conductive auxiliary agent to be contained in the positive electrode film. For example, a carbon material such as carbon black, acetylene black, ketjen black, graphite, carbon fiber, or carbon nanotube is preferable. Among the carbon materials, acetylene black or ketjen black is particularly preferable from the viewpoint of the amount of addition and conductivity, and the productivity of the coating positive electrode mixture slurry. The conductive auxiliary agent can be contained in the negative electrode film, and may be preferable.

  The binder used in this embodiment preferably also contains a binder for binding the active material and the conductive additive. As the binder, for example, a polyvinylidene fluoride-based polymer (a polymer of a fluorine-containing monomer group containing 80% by mass or more of vinylidene fluoride as a main component monomer) or a rubber-based polymer is preferably used. Two or more of the above polymers may be used in combination. The binder is preferably provided in the form of a solution dissolved in a solvent.

  Examples of the fluorine-containing monomer group for synthesizing the polyvinylidene fluoride-based polymer include vinylidene fluoride, or a mixture of vinylidene fluoride and another monomer, and a monomer mixture containing 80% by mass or more of vinylidene fluoride. Can be mentioned. Examples of other monomers include vinyl fluoride, trifluoroethylene, trifluorochloroethylene, tetrafluoroethylene, hexafluoropropylene, and fluoroalkyl vinyl ether.

  Examples of the rubber polymer include styrene butadiene rubber (SBR), ethylene propylene diene rubber, and fluorine rubber.

  Content of the binder in an electrode film is 0.1 mass% or more on the basis of the electrode film after drying, More preferably, it is 0.3 mass% or more, 10 mass% or less, Furthermore, it is 5 mass% or less. More desirable. If the binder content is too small, not only is the solidification in the drying process insufficient, but the mechanical strength of the electrode film after drying is insufficient, and the electrode film may peel from the current collector foil. Moreover, when there is too much content of a binder, there exists a possibility that the amount of active materials in an electrode film may reduce and battery capacity may become low.

As the insulating material used in this embodiment, an inorganic oxide such as Al ₂ O ₃ (alumina) or SiO ₂ (silica) can be used. Moreover, a slurry in which fine particles of polypropylene or polyethylene are confused may be used, and shutdown performance can be provided by using this slurry. In order to bind the inorganic oxide particles used for the insulating material, a resin is used as a binder. The binder used for the electrode film is preferably used as the binder.

  The current collector foil used in the present embodiment is not limited to a sheet-like foil. As the substrate, for example, pure metal or alloy conductive material such as Al (aluminum), Cu (copper), stainless steel or Ti (titanium) is used, and the shape thereof is a net, punched metal, foam metal or plate. A foil processed into a shape is used. As the thickness of the current collector foil, for example, 5 μm to 30 μm, more preferably 8 μm to 16 μm is selected. Moreover, the thickness of the electrode film formed on one surface (surface) of the current collector foil is a thickness after drying, for example, about 50 μm to 200 μm.

  In addition, the lithium ion battery in this Embodiment can be manufactured similarly to the conventional lithium ion battery except including the positive electrode and negative electrode which are manufactured by the method mentioned above. There is no particular limitation on the structure or size of the battery can or the structure of the electrode body having the positive electrode and the negative electrode as main components.

  Thus, according to the present embodiment, the first insulating material IF1 applied to the surface of the current collector foil PEP so as to sandwich the electrode material (the positive electrode material and the negative electrode material) in the second direction has a mountain shape. However, the upper surface of the electrode material applied to the surface of the current collector foil PEP is substantially flat. Therefore, the electrode film (positive electrode film and negative electrode film) and insulating film are removed by cutting and removing the region where the raised portion of the first insulating material IF1 is formed after the electrode plate (positive electrode plate and negative electrode plate) is completed. An electrode plate (a positive electrode plate and a negative electrode plate) having a uniform thickness composed of (a part of the insulating film remaining without being removed) and a separator formed on the upper surface thereof is manufactured. Thereby, a positive electrode and a negative electrode can be tied together without gap, and also an electrode winding body can be easily inserted into a battery can without gap.

  Further, the price of the insulating material contained in the first insulating material IF1 that is cut and the raised portion is discarded is lower than the price of the active material contained in the electrode material (positive electrode material and negative electrode material). Therefore, instead of discarding part of the electrode material (positive electrode material and negative electrode material), discarding a part of the first insulating material IF1 can reduce the manufacturing cost of the lithium ion battery.

  As mentioned above, the invention made by the present inventor has been specifically described based on the embodiment. However, the present invention is not limited to the embodiment, and various modifications can be made without departing from the scope of the invention. Needless to say.

  In the said embodiment, although the lithium ion battery was illustrated as a secondary battery which is an electrical storage device, and the manufacturing apparatus and the manufacturing method were demonstrated, it is not limited to this.

BRL Back roll CO Battery can DC Slit coater DRY Drying chamber EM Electrode material IF Insulating material IF1 First insulating material IF2 Second insulating material LS Liquid supply part LS1 First liquid supply part LS2 Second liquid supply part LS3 Third liquid supply part M1 Electrode plate manufacturing apparatus NE Negative electrode plate NET Negative electrode terminal NRL Knife roll PAS Positive electrode material PE Positive electrode plate PEL Positive electrode lead PEP Current collector PET Positive electrode terminal RC Roll knife coater RC0 Roll knife coater SL1 Unwinding roll SL2 Winding roll SP Separator WA wall

Claims (11)

A transport mechanism for transporting the current collector foil in the first direction;
A first coating mechanism for applying a slurry-like electrode material containing an active material to the surface of the current collector foil;
With
The first coating mechanism is
A first roll disposed on the surface side of the current collector foil;
A second roll facing the first roll and disposed on the back side of the current collector foil;
A first liquid supply section for supplying a first solution containing an insulating material to the surface of the current collector foil between the first roll and the second roll;
A second liquid supply unit for supplying the electrode material to the surface of the current collector foil between the first roll and the second roll;
A third liquid supply unit for supplying a second solution containing an insulating material to the surface of the current collector foil between the first roll and the second roll;
With
The electricity storage device, wherein the first liquid supply unit and the third liquid supply unit are arranged across the second liquid supply unit in a second direction orthogonal to the first direction and the surface of the current collector foil Manufacturing equipment. The apparatus for manufacturing an electricity storage device according to claim 1,
Walls are provided between the first liquid supply unit and the second liquid supply unit, and between the second liquid supply unit and the third liquid supply unit, respectively, and the second direction of the wall An apparatus for manufacturing an electricity storage device that can adjust the thickness of the battery. In the manufacturing apparatus of the electrical storage device according to claim 1 or 2,
The electrical storage device manufacturing apparatus, wherein the first solution, the electrode material, and the second solution are simultaneously supplied to the surface of the current collector foil between the first roll and the second roll. In the electrical storage device manufacturing apparatus according to any one of claims 1 to 3,
The electrical storage device manufacturing apparatus, wherein an interval between the first roll and the second roll is 50 μm to 200 μm. In the electrical storage device manufacturing apparatus according to any one of claims 1 to 4,
The first roll is fixed;
The said 2nd roll is a manufacturing apparatus of the electrical storage device which has the rotation function to drive the said current collection foil to the said 1st direction. In the manufacturing apparatus of the electrical storage device of any one of Claims 1-5,
An apparatus for manufacturing an electricity storage device, further comprising a second coating mechanism for applying a slurry-like insulating material containing an insulating material on top surfaces of the first solution, the electrode material, and the second solution. The power storage device manufacturing apparatus according to claim 6,
A drying mechanism for drying the first solution, the electrode material, the second solution, and the insulating material;
An apparatus for manufacturing an electricity storage device, further comprising: (A) Applying a slurry-like electrode material containing an active material to the surface of the current collector foil traveling in the first direction, the electrode in the second direction orthogonal to the first direction and the surface of the current collector foil Applying a solution containing an insulating substance to the surface of the current collector foil on both sides of the material;
(B) After the step (a), applying a slurry-like insulating material containing an insulating substance on the electrode material and the upper surface of the solution;
(C) after the step (b), drying the electrode material, the solution and the insulating material;
A method for manufacturing an electricity storage device. In the manufacturing method of the electrical storage device of Claim 8,
The method for manufacturing an electricity storage device, wherein the electrode material and the solution are simultaneously applied to the surface of the current collector foil. In the manufacturing method of the electrical storage device of Claim 8 or Claim 9,
The method for manufacturing an electricity storage device, wherein the electrode material and the solution are in contact with each other on the surface of the current collector foil. In the manufacturing method of the electrical storage device according to any one of claims 8 to 10,
The method for manufacturing an electricity storage device, wherein the upper surface of the electrode material is flat.

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