KR100301996B1 - Manufacture of lithium ion secondary battery - Google Patents

Abstract

A battery composed of a positive electrode 1, a negative electrode 4, a separator 7 and an electrolyte, with an object of providing a method for manufacturing a lithium ion battery having a compact, high performance and stable characteristics, which can take any shape such as thin shape. In the manufacturing method of the present invention, after applying a binder resin solution containing fluorine-based resin or polyvinyl alcohol as a main component to the separator 7, the laminated body 12 having each of the positive electrode 1 and the negative electrode 4 superimposed on the separator 7 A battery laminate having a plurality of layers) is formed, the battery laminate is pressurized and dried to form a flat battery laminate, and then the flat battery laminate is impregnated with an electrolyte solution.

Description

Manufacturing method of lithium ion secondary battery {MANUFACTURE OF LITHIUM ION SECONDARY BATTERY}

In order to cope with the miniaturization and light weight of portable electronic devices, the improvement of electric capacity in a battery is the most important performance improvement problem, and various batteries have been developed and improved.

Lithium-ion secondary batteries are secondary batteries that are expected to have the highest capacity among the batteries so far, and improvements are actively being made.

A lithium ion secondary battery has a positive electrode, a negative electrode, and the ion conductive layer which fits in this positive electrode and a negative electrode as a main component.

In the lithium ion secondary battery currently provided for practical use, this ion conductive layer is used in which only an electrolyte solution is layered on a separator made of a porous film such as polypropylene.

Lithium ion secondary batteries, which have been put to practical use at present, use a rigid outer tube made of stainless steel, and are pressurized to maintain electrical bonding between the positive electrode, the ion conductive layer, and the negative electrode.

However, the outer tube increases the weight of the lithium ion secondary battery, making it difficult to reduce the size and weight of the lithium ion secondary battery, and also make it difficult to form an arbitrary shape due to the rigidity of the outer tube.

In order to reduce the size, weight, and arbitrary shape of a lithium ion secondary battery, it is necessary to join a positive electrode, an ion conductive layer, a negative electrode, and an ion conductive layer, and to maintain the state without pressurizing from the outside.

In this method, US Pat. No. 5,437,692 discloses bonding a positive electrode and a negative electrode to an ion conductive layer using a lithium ion conductive polymer as the ion conductive layer and using an adhesive layer containing a lithium compound.

In addition, WO 95 / 15,589 discloses forming a plastic ion conductive layer and joining a positive electrode and a negative electrode in the plastic ion conductive layer.

However, in the method disclosed in U.S. Patent No. 5,437,692, sufficient bonding strength is not obtained, it cannot be made thin enough as a battery, high ion conductivity resistance between the ion conductive layer, the positive electrode and the negative electrode, and the battery characteristics such as charge and discharge characteristics are practical. It was a mountain problem.

Further, in WO 95 / 15,589, there is a problem in that sufficient bonding strength is not obtained because the plastic ion conductive layer is bonded, and it cannot be made sufficiently thin as a battery.

The present invention has been made to solve the above problems, the positive electrode and the negative electrode and the ion conductive layer (separator) is in close contact with the adhesive resin to ensure sufficient bonding strength between the electrode and the separator, and at the same time the ion conduction between the positive electrode, negative electrode and the separator It is to provide a method for producing a lithium ion secondary battery that can ensure the resistance of a battery using a conventional outer tube.

[Initiation of invention]

The method for producing a first lithium ion secondary battery of the present invention is a step of forming each electrode formed by forming a positive electrode and a negative electrode active material layer on a positive electrode and a negative electrode current collector, and a fluorine resin or polyvinyl alcohol as a main component. The process of apply | coating the binder resin solution melt | dissolved in the solvent to a separator, The process of forming the several layers of the laminated body which alternately laminated each said electrode between these separators, The several layers of this laminated body are dried, pressing and drying, and evaporating a solvent. To form a plate-shaped battery laminate and a step of impregnating an electrolyte solution to the plate-shaped battery laminate.

The manufacturing method of the 2nd lithium ion secondary battery of this invention is a method in which the several layers of a laminated body are formed through the separator which separated in the manufacturing method of said 1st lithium ion secondary battery.

In the method of manufacturing a third lithium ion secondary battery of the present invention, in the method of manufacturing the first lithium ion secondary battery, a method in which a plurality of layers of the laminate are wound is formed through a separator.

The manufacturing method of the 4th lithium ion secondary battery of this invention is a method in which the several layers of a laminated body are formed through the folded separator in the manufacturing method of said 1st lithium ion secondary battery.

According to the method of manufacturing the first to fourth lithium ion secondary batteries, it is possible to prevent peeling between the electrode and the separator made of the positive electrode and the negative electrode active material, the positive electrode and the negative electrode current collector bonded to each of the active materials, and the separator. Since the structure as a battery can be maintained even without one body, the battery can be made lighter and thinner, and the charge and discharge characteristics are improved by the binder resin solution applied to the separator, and the multilayer body has a compact structure, thereby making it compact. A stable lithium ion secondary battery is obtained.

In addition, when an external force or internal thermal stress acting on the formed battery is applied, it is not a separator but is destroyed between the active material layer of the electrode and the current collector, so that stability can be maintained.

In the fifth method of manufacturing a lithium ion secondary battery of the present invention, in the first lithium ion secondary battery, the binder resin solution contains dimethylformamide as a solvent, and the solution contains fluorine resin or polyvinyl alcohol. It is a solution that is.

In the manufacturing method of the sixth lithium ion secondary battery of the present invention, in the manufacturing method of the fifth lithium ion secondary battery, 3 to 25 parts by weight of fluorine resin or polyvinyl alcohol in dimethyl formamide, preferably It is the method of the solution contained 5-15 weight part.

Thereby, the process of evaporating a solvent becomes short time and the lithium ion secondary battery excellent in the charge / discharge characteristic is obtained.

The manufacturing method of the 7th lithium ion secondary battery of this invention is a method of drying in 80 degreeC or less airflow in the manufacturing method of the said 1st lithium ion secondary battery.

Thereby, time required for drying can be shortened.

The manufacturing method of the 8th lithium ion secondary battery of this invention is a method of plasma-processing the separator surface before apply | coating a binder resin solution to a separator in the manufacturing method of said 1st lithium ion secondary battery.

Thereby, adhesiveness can be improved further.

The present invention relates to a method for producing a lithium ion secondary battery.

More specifically, the present invention relates to a method for manufacturing a lithium ion secondary battery that can be thinner and lighter in any shape.

1, 2, and 3 are main cross-sectional schematic diagrams showing one embodiment of a lithium ion secondary battery obtained by the manufacturing method of the present invention.

4 is a cross-sectional view schematically showing the configuration of a single laminate shown in FIGS. 1, 2, and 3.

Best Mode for Carrying Out the Invention

EMBODIMENT OF THE INVENTION Below, embodiment of this invention is described according to drawing.

1, 2, and 3 are schematic cross-sectional views of an essential part showing an embodiment of a lithium ion secondary battery obtained by the manufacturing method of the present invention, and FIG. 4 is shown in FIGS. 1, 2, and 3. It is sectional drawing which shows typically the structure of a single laminated body.

In each figure, 12 is a laminated body, and this laminated body 12 is the positive electrode 1 formed by shape | molding the positive electrode active material layer 3 on the positive electrode collector 2 which consists of metals, such as aluminum foil, and the same metal. The negative electrode 4 formed by molding the negative electrode active material 6 on the negative electrode current collector 5, the separator 7 having the electrolyte containing lithium ions, the separator 7, the positive electrode 1, and the separator 7. ) And the negative electrode 4 are constituted by a binder resin layer 8.

The binder resin layer 8 has fine pores, and these fine pores hold the electrolyte solution.

As the positive electrode current collector 2 and the negative electrode current collector 5, any metal that is stable in a lithium ion secondary battery can be used, and aluminum is preferably used as the positive electrode current collector 2 and copper as the negative electrode current collector.

The shape of the current collectors 2 and 5 can be used for both foil and reticulated expanded metal, but the bonding strength with the active material layers 3 and 6 is greater in surface area such as reticulated and expanded metal. It is preferable to obtain and to facilitate the impregnation of the electrolytic solution after bonding.

The active material included in the positive electrode active material layer 3 includes, for example, a composite oxide of a transition metal such as lithium, cobalt, manganese or nickel, a composite oxide of lithium and a chalcogenide, or a transition metal in the composite oxide. Composite oxides, those having various microaddition elements in these composite oxides, etc. are used and are not particularly limited.

Although the carbonaceous material is preferably used for the active material included in the negative electrode active material 6, the battery of the present invention can be used irrespective of chemical characteristics, shape, and the like.

The material used for the separator 7 can be used as long as sufficient strength can be obtained while impregnating the electrolyte solution with an insulating porous membrane, a net, a nonwoven fabric, and the like. The use of a porous membrane made of polypropylene, polyethylene, or the like ensures adhesion and safety. It is preferable at the point of view.

As the binder resin for forming the binder resin layer 8, for example, a mixture containing fluorine resin or fluorine resin as a main component, or a mixture containing polyvinyl alcohol or polyvinyl alcohol as a main component is used.

Specific examples of the fluorine resin include polymers or copolymers having fluorine atoms such as vinylidene fluoride and 4-fluoroethylene in a molecular structure, polymers or copolymers having vinyl alcohol in a molecular skeleton, or polymethyl methacrylate, polystyrene, polyethylene , Polypropylene, polyvinylidene chloride, polyvinyl chloride, polyacrylonitrile, mixtures with polyethylene oxide and the like can be used.

In particular, polyvinylidene fluoride of fluororesin is suitable.

As a solvent used for forming the binder resin layer 8, a solvent with high polarity, such as N-methylpyrrolidone, NN'- dimethylformamide, dimethyl sulfooxide, can be used, for example.

In particular, from the viewpoint of safety, N-methylpyrrolidone is suitable.

The electrolyte solution may be prepared by mixing LiPF ₆ , LiClO ₄ , LiBF ₄ , and LiCF ₃ SO _{3 in a} mixture or a mixture of ether-based solvents such as dimethoxyethane, diethoxyethane, dimethyl ether diethyl ethene, and ester-based solvents such as ethylene carbonate and propylene carbonate. It is possible to use electrolytes such as LiN (CF ₃ SO ₂ ) ₂ , LiC (CF ₃ SO ₂ ) _3, and the like.

Next, the manufacturing method of the laminated body of the lithium ion secondary battery shown in FIG. 1 is demonstrated.

First, an appropriate amount of binder resin is mixed with each of the active materials of the positive electrode 1 and the negative electrode 4 (the conductive material such as graphite powder is further mixed into the active material of the positive electrode 1) to form a paste, and each of the paste-like active materials Is applied to the positive electrode current collector 2 and the negative electrode current collector 5, and dried to form the electrodes of the positive electrode 1 and the negative electrode 4, respectively.

As the binder resin used herein, various kinds of polyethylene and the like can be used in addition to the same main components as those used for the binder resin layer 8.

Next, the coating binder resin solution is uniformly applied to the entire surface of the separator 7.

For the application, a pulling method drawn up through the binder resin solution, a bar coater method of dropping the binder resin onto the separator and applying it uniformly to the bar coater, a spray method of applying the binder resin to the separator by the spray method, and the like can be used.

In addition, when a fluororesin is used for the separator, the surface can be plasma treated to ensure adhesion.

When the binder resin solution is applied to the electrode instead of the separator, the binder resin solution soaks in the electrode and the adhesive strength between the separator and the electrode decreases.

In addition, as the binder resin solution soaks in the electrode, the conduction path of lithium ions decreases and battery characteristics decrease.

Moreover, when the binder resin for electrode formation contains polyvinylidene fluoride or polyvinyl alcohol as a component, it melt | dissolves with the binder resin solution for application | coating, and the intensity | strength of an electrode falls.

Application of the binder resin solution to the separator prevents dissolution of the binder resin solution into the electrode, preventing dissolution of the binder resin for forming the electrode by the binder resin solution, increasing the adhesion between the separator and the electrode, and decreasing the strength of the electrode. Can be suppressed.

Moreover, the binder resin layer suitably formed in the interface with a separator improves the utilization efficiency of the active material in electrode inside with respect to dope and undoping of lithium ion.

That is, since the mobility of lithium ions is the same in the electrolyte, the dope and dedope of lithium ions are inclined in the active material portion adjacent to the separator, and there is a problem that the active material in the electrode is not effectively utilized. The surface of the active material in the vicinity of the separator is covered by the binder resin liquid and the active portion is smaller than the active material in the electrode, so that the doping and de-doping speeds of the active material in the vicinity of the separator and the active material in the electrode are uniform and the charge and discharge efficiency is improved.

As the binder resin solution, an N-methylpyrrolidone solution containing 3 to 25 parts by weight, preferably 5 to 15 parts by weight of polyvinylidene fluoride or polyvinyl alcohol as a main component is used well.

When the binder resin solution is too thin, sufficient resin is not applied and the adhesive strength is insufficient. When the solution is too thick, the amount of resin to be applied is too great to reduce the ion conductivity between the electrodes, resulting in poor battery characteristics.

Next, before the binder resin solution is dried between the separators to which the binder resin solution is applied, one of the electrodes is stacked, heated and dried by applying pressure on both sides with a pressure roller or the like, and then cut to a certain size to sandwich the one electrode. Applying the binder resin solution to the outer surface of the separator and superimposing the other electrode cut to a certain size, and repeating the step of overlapping the separator sandwiching one electrode coated with the binder resin solution on the outer surface, the battery laminated body Several layers of the laminate are prepared, and are heated and tempered while pressing several layers of the battery laminate to form a flat battery laminate.

As for the heating temperature at this time, 60-100 degreeC is preferable.

At temperatures lower than 60 ° C, it takes a very long time to dry and is unsuitably fair. At temperatures higher than 100 ° C, there is a possibility of adversely affecting separators and the like, which is not preferable.

Thereafter, it may be necessary to continue heating to remove the residual solvent, but in this case, it is not necessary to apply pressure in particular.

Decompression at the time of heating is effective under a short time of drying time, but it is not a requirement.

A flat plate battery laminate having a plurality of layers of a laminate in which the positive electrode 1 and the negative electrode 4 formed as described above are attached to the separator 7 is inserted into an alumina laminate, and the electrolytic solution is impregnated under reduced pressure. By heat-sealing according to a laminate film, a lithium ion secondary battery is completed.

As described above, peeling between the positive electrode and the negative electrode active material and each electrode made of the positive electrode and the negative electrode current collector bonded to each of the active materials and the separator can be prevented, and the structure as the battery can be maintained even without the rigid body. Therefore, the battery can be made compact, the battery can be made thinner and thinner, and the lithium ion secondary battery with good charge and discharge characteristics can be obtained by the binder resin solution coated on the separator.

In addition, when an external force or internal thermal stress that is likely to deform the formed battery acts, it is not a separator but is destroyed between the active material layer of the electrode and the current collector, so that safety can be maintained.

In addition, dimethylformamide is used as the solvent for the binder resin solution, which has a lower boiling point than N-methylpyrrolidone (boiling point of 202 ° C.) and is capable of dissolving a fluororesin such as polyvinylidene fluoride or a binder resin containing polyvinyl alcohol as a main component. As a result, the step of evaporating the solvent is shortened.

The binder resin mainly containing polyvinylidene fluoride or polyvinyl alcohol in dimethylformamide is 3 to 25 parts by weight, preferably 5 to 15 parts by weight.

Moreover, the time required for drying can be shortened by performing heat drying after overlapping each electrode on the separator which apply | coated the binder resin solution to airflow below 80 degreeC.

The embodiment is shown below including the examples of FIGS. 2 and 3 and the present invention is explained in more detail.

Example 1

(Production of positive electrode)

A positive electrode active material paste prepared by dispersing 87 parts by weight of LiCoO ₂ , 8 parts by weight of graphite powder and 5 parts by weight of polyvinylidene fluoride in N-methylpyrrolidone (hereinafter referred to as NMP) was prepared using a doctor braiding method to a thickness of 300 μm. It applied and the positive electrode active material thin film was formed.

An aluminum mesh having a thickness of 30 μm to be the positive electrode current collector 2 was placed on the upper portion thereof, and a positive electrode active material paste adjusted to a thickness of 300 μm by the doctor braid method was further applied thereon.

This was allowed to stand for 60 minutes in a dryer at 60 deg. C to obtain a semi-dried state to form an integrated body of the positive electrode current collector 92) and the positive electrode active material.

The laminated body was rolled to 400 micrometers, and the positive electrode 1 in which the positive electrode active material layer 3 was formed was produced.

After immersing this positive electrode 1 in electrolyte solution, the peeling strength of the positive electrode active material layer 3 and the positive electrode collector 2 was measured, and the value of 20-25 gf / cm was displayed.

(Production of negative electrode)

A negative electrode active material paste prepared by dispersing 95 parts by weight of mesophase microbeads (manufactured by Osaka Gas) and 5 parts by weight of polyvinylidene fluoride in NMP was applied to a thickness of 300 mu m by a doctor braid method to form a negative electrode active material film.

A band-like copper wire having a thickness of 20 μm to be the negative electrode current collector 5 was placed on the upper portion thereof, and a negative electrode active material paste adjusted to a thickness of 300 μm by the doctor braid method was further applied on the upper portion thereof.

This was left to stand for 60 minutes in a 60 degreeC dryer to make it semi-dry, and the electrical power collector of the negative electrode collector 5 and the negative electrode active material was formed.

By rolling this laminated body at 400 micrometers, the negative electrode 4 in which the negative electrode active material layer 6 was formed was produced.

After immersing this negative electrode 4 in electrolyte solution, the peeling strength of the negative electrode active material layer 6 and the negative electrode collector 5 was measured, and the value of 5-10 gf / cm was displayed.

(Production of battery)

A binder resin solution was prepared by mixing 5 parts by weight of polyvinylidene fluoride and 95 parts by weight of NMP with a composition ratio and sufficiently stirring to obtain a uniform solution.

Next, the binder resin was added dropwise to each one side of two continuous elongated porous polyflohylene sheets (trade name Celgard # 2400 manufactured by Hext) used as the separator 7, and a filament having a diameter of 0.5 mm was used. The binder resin solution was apply | coated uniformly to the whole surface of a separator by moving the separator image the bar coater wound on the 1 cm glass tube finely.

Next, before the binder resin is dried, the positive electrode 1, which is one electrode, is brought into close contact with the coated surface of the polypropylene sheet, and pressure is applied from both sides with a pressure roller or the like. A binder resin solution is also applied to the uncoated surface of the cut polypropylene sheet using a bar coater, and the negative electrode 4, which is the other electrode cut to a predetermined size, is overlapped and adhered to the coated surface. The binder resin solution was apply | coated to the uncoated surface of the polypropylene sheet | stacked using the bar coater, and this coated surface was superimposed on the said negative electrode.

This fixing was repeated, and several layers of the laminated body were produced.

The plate-shaped battery laminated body shown in FIG. 1 was formed by evaporating and removing NMP which is a solvent by heating to 60 degreeC no-weather in a dryer, pressing the multiple layers of this laminated body.

As the NMP evaporates, the inverter resin becomes a porous membrane having continuous holes.

Subsequently, the plate-shaped battery laminate formed into a certain size was inserted into an aluminate film stand, and under reduced pressure, a mixed solvent of ethylene carbonate (manufactured by Kanto Kagaku Co., Ltd.) and 1,2-dimethocycital (manufactured by Wako Pure Chemical Industries, Ltd.). After impregnating an electrolytic solution dissolved at a concentration of LiPF ₆ (manufactured by Toyosei Co., Ltd.) at a concentration of 1.0 ml / dm ^{3 in} a molar ratio of 1: 1, and carrying out a treatment with a hydride, the battery laminate shown in FIG. A lithium ion secondary battery was produced.

Example 2

Only the binder resin solution in Example 1 was changed as follows, and in the same manner as in Example 1, a lithium ion secondary battery having the battery laminate shown in FIG. 1 was produced.

5 parts by weight of polyvinyl alcohol was mixed at a composition ratio of 95 parts by weight of NMP, and sufficiently stirred to form a uniform solution, thereby preparing a binder resin solution.

Example 3

Dimethyl formamide was used in place of NMP, which is a solvent of the binder resin solution in Examples 1 and 2, and the others were the same as those of Example 1, and the lithium ion secondary battery having the flat plate cell laminate shown in FIG. Got it.

In this case, the process of evaporating a solvent could be shortened compared with Example 1.

Example 4

Instead of NMP, which is the solvent of the binder resin solution in Examples 1 and 2, dimethylformamide was used, and the step of evaporating the solvent was exposed to a 60 ° C air stream. Got it.

In this case, the process of drying a solvent was shortened compared with Example 1, 2, and 3.

Peel strength measurement of the lithium ion secondary batteries obtained in Examples 1 to 4 was carried out.

The adhesion strength between the positive electrode 1 and the separator 7, the negative electrode 4 and the separator 7 is 23 gf / cm and 12 gf / cm, respectively, and the active material layers 3 and 6 and the current collector ( It was more than the adhesive strength of 2) and (5).

Example 5

The flat plate cell laminated body which has several layers of a laminated body was formed through the several separator which isolate | separated the said Example 1.

In the present Example, the flat battery laminated body which has multiple layers of a laminated body was formed through the separator wound up, and the others were obtained like the Example 1, and the lithium ion secondary battery which has the battery laminated body shown in FIG.

(Production of battery)

A binder resin solution was applied to one side of each of the two strip-shaped separators 7 made of porous polypropylene sheet (trade name Celgard # 2400), and the strip-shaped negative electrode 4 was formed between the coated surfaces. Or positive electrode), and brought into close contact with each other, followed by heating and drying while pressing.

A binder resin solution is applied to one of the strip-shaped separators in which the negative electrode 4 (or the positive electrode) is bonded therebetween, and one end of the separator is bent a certain amount to sandwich the positive electrode 1 (or negative electrode) at the bent portion, and the sheet is passed through the laminator. I was.

Subsequently, a binder resin solution is applied to the other side of the strip-shaped separator, and the other positive electrode 1 (or negative electrode) is placed at a position opposite to the positive electrode 1 (or negative electrode) which is bent and folded into the folded portion, and the separator is long. It winds up in a state, repeats the process of winding up a separator while abutting another positive electrode 1 (or negative electrode), and forms several layers of a laminated body, and it drys, pressing several layers of this laminated body, and FIG. The flat plate cell laminated body as shown was produced.

In the present embodiment, an example of winding up the separator 7 is shown. However, the separator is formed while folding the strip-shaped separator bonded between the negative electrode 4 (or the positive electrode) and abutting the positive electrode 1 (or negative electrode). You may repeat a folding process.

Example 6

Only the point of simultaneously winding a strip-shaped separator, a positive electrode, and a negative electrode is different from Example 5, and others are the same as Example (1) and (5). Lithium ion 2 which has a flat plate battery laminated body shown in FIG. A battery was produced.

(Production of battery)

A strip-shaped negative electrode 4 (or a cathode) is disposed between two strip-shaped separators 7 made of porous polypropylene sheet (trade name Celgard # 2400), and the strip-shaped positive electrode 1 (or The negative electrode) is arranged to protrude a certain amount to the outside of one separator 7.

Binder resin is applied to the inner surface of each separator 7 and the outer surface of the separator 7 on which the positive electrode 1 (or negative electrode) is disposed, and the positive electrode 1 (or negative electrode) and the two separators 7 are separated. And the negative electrode 4 (or the positive electrode) are piled up and laminated, and then binder resin is applied to the outer surface of the other separator 7, and the protruding positive electrode 1 (or negative electrode) is folded and joined to this coated surface. The laminated separator is rolled up in a mandatory state, as if the folded positive electrode 1 (or negative electrode) is wrapped inside, to form several layers of the laminate, and dried while pressing several of the laminates to form a flat battery laminate. Produced.

In addition, the battery characteristics of the lithium ion secondary batteries obtained in Examples 1 to 6 were evaluated, and 100 Wh / kg was obtained by weight energy density, and after 200 charge / discharge cycles were performed at the current value C / 2, 75% were maintained.

It is used as a secondary battery for portable electronic devices such as portable personal computers and mobile phones, and it is possible to improve the performance of the battery and to make it compact, lightweight, and arbitrarily shaped.

Claims (12)

Forming each electrode formed on each of a positive electrode and a negative electrode active material layer on a positive electrode and a negative electrode current collector; applying a binder resin solution obtained by dissolving a fluororesin or polyvinyl alcohol in a solvent as a main component to a separator; Alternately superimposing each of the electrodes, forming a plurality of layers of the positive electrode, the negative electrode, and the separator, and drying the various layers of the laminate while pressing to evaporate a solvent to form a flat electrode laminate. And a step of impregnating an electrolyte solution into the plate-shaped electrode laminate, the method for producing a lithium ion secondary battery. The manufacturing method of the lithium ion secondary battery of Claim 1 formed in the laminated body through the separator isolate | separated. A method for producing a lithium ion secondary battery according to claim 1, wherein a plurality of layers of the laminate are formed through a separator wound up. A method for producing a lithium ion secondary battery according to claim 1, wherein a plurality of layers of the laminate are formed through folded separators. A method for producing a lithium ion secondary battery according to claim 1, wherein the binder resin solution is a solution containing dimethylformamide as a solvent and a fluorine resin or polyvinyl alcohol contained in the solvent. The lithium ion secondary material according to claim 5, wherein the binder resin solution is a solution containing 3 to 25 parts by weight, preferably 5 to 15 parts by weight, of fluorine resin or polyvinyl alcohol in dimethylformamide. Method for producing a battery. Drying is performed in airflow of 80 degrees C or less, The manufacturing method of the lithium ion secondary battery of Claim 1 characterized by the above-mentioned. The method for producing a lithium ion secondary battery according to claim 1, wherein the surface of the separator is subjected to plasma treatment before the binder resin solution is applied to the separator. The method of claim 1, The step of saturating further comprises the step of drying the laminate upon heating. The method of claim 1, The saturation step is a method for producing a lithium ion secondary battery characterized in that it comprises the step of exhausting. The method of claim 1, In addition, the method comprises the steps of covering the laminate with a flexible packaging and sealing the flexible packaging method of producing a lithium ion secondary battery. The method of claim 11, The flexible packaging is made of resin laminated aluminum, and the step of sealing the flexible packaging comprises a heating compression step.