JP2003092142A - Nonaqueous electrolyte battery and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain good battery characteristics by suppressing the internal resistance of a battery. SOLUTION: This nonaqueous electrolyte battery is equipped with a positive electrode 2 in which a positive mix layer 8 is formed on the main surface of a positive current collector 7 and a solid electrolyte 9 is impregnated in the positive mix layer 8; a negative electrode 3 in which a negative mix layer 11 is formed on the main surface of a negative current collector 10 and the solid electrolyte 9 is impregnated in the negative mix layer 11; and a separator 4 arranged between the positive electrode 3 and the negative electrode 4, and a void volume of the positive mix layer 8 and the negative mix layer 11 to the total volume is in a range of 25-35%, the solid electrolyte 9 is impregnated in 60% or more of each pore volume, and thereby, the electrical contact between the positive mix layer 8 and the solid electrolyte 9 and between the negative mix layer 11 and the solid electrolyte 9 is made good, the internal resistance of the battery is suppressed, and battery characteristics are enhanced.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a non-aqueous electrolyte battery having a separator interposed between a positive electrode and a negative electrode, and a method for manufacturing the same.

[0002]

2. Description of the Related Art In recent years, for example, a notebook type portable computer, a mobile phone, a camera-integrated VTR (Vi
Development of lightweight and high-energy-density secondary batteries is underway as a power source for portable electronic devices such as deo tape recorders.

As a secondary battery having this high energy density, for example, a positive electrode in which a positive electrode mixture layer containing a positive electrode active material such as a metal oxide or a metal sulfide is formed on the main surface of a positive electrode current collector, , A negative electrode on which a negative electrode mixture layer containing a negative electrode active material such as a carbon material capable of doping and dedoping lithium ions is formed on the main surface of the negative electrode current collector is laminated via a separator There are lithium-ion secondary batteries and the like that are charged and discharged accordingly.

With respect to this lithium ion secondary battery, a small battery with high safety without leakage is required with the spread of portable electronic devices, and the miniaturization and the safety are improved. In order to realize such a thing, research on a solid electrolyte in which an electrolytic solution is solidified is actively conducted. Specifically, there are solid electrolytes in which a lithium salt is dissolved in a polymer, gel-like solid electrolytes containing a non-aqueous solvent together with a lithium salt (hereinafter referred to as gel electrolytes), and the like, which have received attention. There is.

In a lithium ion secondary battery using these solid electrolytes, for example, charge and discharge are performed by stacking a positive electrode and a negative electrode, each having a solid electrolyte formed on each mixture layer, with a separator interposed therebetween. Therefore, it is possible to realize a demand that a battery using an electrolytic solution is difficult to realize and that leakage is prevented.

[0006]

However, in the lithium ion secondary battery using the solid electrolyte as described above, the solid electrolyte does not have fluidity like an electrolytic solution and has a high viscosity. It was difficult to penetrate into the agent layer and the positive electrode mixture layer.

Therefore, in this lithium-ion secondary battery, the internal resistance is increased due to the poor electrical contact between the mixture layers in the positive and negative electrodes and the solid electrolyte.
There is a problem that the battery characteristics such as large current discharge load characteristics and low temperature characteristics are deteriorated.

Further, in the lithium ion secondary battery using the solid electrolyte, when the positive electrode and the negative electrode having the solid electrolyte formed on the respective mixture layers are laminated via the separator, the solid electrolyte and the separator are separated. There was a gap between them.

Therefore, in this lithium ion secondary battery, since the distance between the positive electrode and the negative electrode is increased due to the gap between the solid electrolyte and the separator, the internal resistance is increased and the movement of lithium ions is facilitated. This makes it difficult to carry out the process, and the charge and discharge efficiency decreases.

Therefore, the present invention has been proposed in view of such a conventional situation, and provides a non-aqueous electrolyte battery and a method for manufacturing the same which can obtain good battery characteristics by suppressing the internal resistance of the battery. The purpose is to provide.

[0011]

In the non-aqueous electrolyte battery of the present invention, a positive electrode mixture layer containing a positive electrode active material is formed on the main surface of a positive electrode current collector, and the non-aqueous electrolyte is formed in the positive electrode mixture layer. Between the impregnated positive electrode and the negative electrode active material-containing negative electrode mixture layer formed on the main surface of the negative electrode current collector, the negative electrode mixture layer impregnated with the non-aqueous electrolyte, and between the positive electrode and the negative electrode. And a separator composed of a porous film interposed between the positive electrode mixture layer and the negative electrode mixture layer, and the pore volume of the total volume of each layer is 25%.
˜35%, and 60% or more of the pore volume of each is impregnated with the non-aqueous electrolyte.

In this non-aqueous electrolyte battery, the positive electrode mixture layer and the negative electrode mixture layer each have a pore volume in the range of 25% to 35% with respect to the total volume thereof, so that the non-aqueous electrolyte is easily impregnated. can do. Further, in this non-aqueous electrolyte battery, since the non-aqueous electrolyte is impregnated into 60% or more of the pore volume of each of the positive electrode mixture layer and the negative electrode mixture layer, the positive electrode mixture layer and the negative electrode mixture layer The electrical contact between the electrolyte and the non-aqueous electrolyte can be improved, and the internal resistance of the battery can be suppressed.

In the non-aqueous electrolyte battery of the present invention, the positive electrode mixture layer containing the positive electrode active material is formed on the main surface of the positive electrode current collector,
The positive electrode in which the positive electrode mixture layer was impregnated with the non-aqueous electrolyte and the negative electrode mixture layer containing the negative electrode active material were formed on the main surface of the negative electrode current collector, and the negative electrode mixture layer was impregnated with the non-aqueous electrolyte. It is provided with a negative electrode and a separator made of a porous film interposed between the positive electrode and the negative electrode, and the positive electrode and the negative electrode are laminated and integrated via the separator by being pressed.

In this non-aqueous electrolyte battery, the positive electrode and the negative electrode are laminated and integrated by being pressed through the separator, and a gap is prevented from being formed between the non-aqueous electrolyte and the separator. As a result, the distance between the positive electrode and the negative electrode is reduced, so that the internal resistance of the battery can be suppressed.

In the method for producing a non-aqueous electrolyte battery of the present invention, a positive electrode mixture layer containing a positive electrode active material is formed on the main surface of a positive electrode current collector, and the positive electrode mixture layer is impregnated with the non-aqueous electrolyte. A first step of producing a positive electrode and a step of producing a negative electrode in which a negative electrode mixture layer containing a negative electrode active material is formed on the main surface of a negative electrode current collector, and the negative electrode mixture layer is impregnated with a non-aqueous electrolyte. The method has a second step and a third step of interposing a separator made of a porous film between the positive electrode and the negative electrode, and the first step and the second step include the positive electrode mixture layer and the negative electrode mixture. The agent layer is formed so that the void volume with respect to each total volume is in the range of 25% to 35%, and the void volume of the positive electrode mixture layer and the negative electrode mixture layer is 6%.
Non-aqueous electrolyte is impregnated to 0% or more.

In this method for producing a non-aqueous electrolyte battery, in the positive electrode mixture layer and the negative electrode mixture layer, the pore volume relative to the total volume of each layer is set in the range of 25% to 35%, whereby the non-aqueous electrolyte is formed. It can be easily impregnated and has 60% of the pore volume of each of the positive electrode mixture layer and the negative electrode mixture layer.
By impregnating the non-aqueous electrolyte above, to improve the electrical contact between the positive electrode mixture layer and the negative electrode mixture layer and the non-aqueous electrolyte, the non-aqueous electrolyte battery suppressed battery internal resistance Manufactured.

In the method for producing a non-aqueous electrolyte battery of the present invention, a positive electrode mixture layer containing a positive electrode active material is formed on the main surface of a positive electrode current collector, and the positive electrode mixture layer is impregnated with the non-aqueous electrolyte. A first step of producing a positive electrode and a step of producing a negative electrode in which a negative electrode mixture layer containing a negative electrode active material is formed on the main surface of a negative electrode current collector, and the negative electrode mixture layer is impregnated with a non-aqueous electrolyte. It has a second step and a third step in which the positive electrode and the negative electrode are laminated and integrated by applying pressure through a separator made of a porous film.

In this method for producing a non-aqueous electrolyte battery, since the positive electrode and the negative electrode are laminated and integrated by pressing through the separator, it is possible to prevent a gap from being formed between the non-aqueous electrolyte and the separator. Since the distance between the positive electrode and the negative electrode is shortened, a non-aqueous electrolyte battery with suppressed battery internal resistance is manufactured.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION A non-aqueous electrolyte battery to which the present invention is applied will be described below with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing a configuration example of a lithium ion secondary battery (hereinafter, referred to as a battery) 1 that is charged and discharged by the movement of lithium ions as a non-aqueous electrolyte battery to which the present invention is applied. .

In the battery 1 shown in FIG. 1, a film-shaped positive electrode 2 and a film-shaped negative electrode 3 are laminated and integrated by being pressed through a film-shaped separator 4 made of a porous film. The wound battery element 5 is inserted into the battery can 6 and hermetically sealed.

Thus, in the battery 1 to which the present invention is applied, since the positive electrode 2 and the negative electrode 3 are laminated and integrated with the separator 4 interposed therebetween, a gap is formed between the positive electrode 2 and the negative electrode 3 and the separator 4. This is prevented from occurring and the distance between the positive electrode 2 and the negative electrode 3 is reduced, so that the internal resistance of the battery can be suppressed.

Further, in the battery 1, since the distance between the positive electrode 2 and the negative electrode 3 is shortened, lithium ions are smoothly moved between the positive electrode 2 and the negative electrode 3, so that the charge / discharge efficiency is improved. be able to.

Further, in the battery 1, since the gap is prevented from being formed between the positive electrode 2 and the negative electrode 3 and the separator 4, the battery element 5 has a high density and the battery capacity can be improved.

In this battery 1, the positive electrode 2 is a positive electrode current collector 7, and a positive electrode mixture coating liquid containing a positive electrode active material is applied to both main surfaces of the positive electrode current collector 7, dried, and pressed. Thus, the positive electrode mixture layer 8 formed under pressure and a solid electrolyte solution containing an electrolyte salt or the like are applied to the positive electrode mixture layer 8, impregnated, and dried to form a layer on the positive electrode mixture layer 8. And the solid electrolyte 9 formed. In the positive electrode current collector 7,
For example, a metal foil such as aluminum is used.

The positive electrode mixture layer 8 contains a positive electrode active material doped / dedoped with lithium ions, a predetermined binder for binding the positive electrode active material to the positive electrode current collector 7, and the like. The positive electrode mixture layer 8 has a pressure of 300 kgf / cm ^{2 to} 600 k.
By performing pressure molding at a pressure in the range of gf / cm ^2, the pore volume with respect to the total volume is in the range of 25% to 35%.

At this time, when the positive electrode mixture layer 8 is formed under pressure at a pressure lower than 300 kgf / cm ² , the pressure is too small, so that the pore volume of the total volume of the positive electrode mixture layer 8 is 35%. When the battery 1 is obtained, the amount of the positive electrode active material decreases and the battery capacity decreases. On the other hand, when the positive electrode mixture layer 8 is formed under pressure at a pressure higher than 600 kgf / cm ² , the pressure is too large, and the pore volume relative to the total volume of the positive electrode mixture layer 8 becomes smaller than 25%. Therefore, when the battery 1 is formed, the space for impregnating the positive electrode mixture layer 8 with the solid electrolyte 9 is reduced, and the electric resistance on the positive electrode 2 side is increased. Therefore, in the positive electrode mixture layer 8, the pressure for forming pressure is 30
It is in the range of ^{0kgf / cm 2 ~600kgf / cm 2} .

As the positive electrode active material, a metal oxide containing lithium, a metal sulfide, a specific polymer, or the like can be used depending on the type of battery. Specifically, Li _x MO
₂ (where M represents one or more transition metals, x varies depending on the charge / discharge state of the battery, and usually 0.05 or more, 1.10 or more).
It is the following. It is possible to use a lithium composite oxide mainly containing). Co, Ni, Mn and the like are preferable as the transition metal constituting the lithium composite oxide.
Specifically, LiCoO ₂ , LiNiO ₂ , LiNi _y
Co _1-y O ₂ (in the formula, 0 <y <1), LiM
Examples thereof include n ₂ O ₄ . The positive electrode active material may be a mixture of a plurality of the above-mentioned lithium composite oxides.

As the binder contained in the positive electrode material mixture layer 8, a binder which is usually used in a positive electrode material mixture of a battery can be used, and a conductive material is used in the positive electrode material mixture layer 8. Additives such as can be added.

The solid electrolyte 9 is obtained by uniformly coating the solid electrolyte solution on the positive electrode mixture layer 8 when the positive electrode mixture layer 8 is impregnated with the solid electrolyte solution, and then leaving it to stand for a predetermined time. 60% or more of the pore volume of the mixture layer 8 will be impregnated.

At this time, when the solid electrolyte 9 impregnated with the pore volume of the positive electrode mixture layer 8 is less than 60% of the pore volume, when the battery 1 is formed, the electric resistance on the positive electrode 2 side is increased. Will become bigger. Note that the impregnation amount of the solid electrolyte 9 with respect to the pore volume of the positive electrode mixture layer 8 is determined by the ratio of the pore volume to the total volume of the positive electrode mixture layer 8 when the amount of the applied solid electrolyte solution is constant. .

Examples of the solid electrolyte 9 include a polymer solid electrolyte containing an electrolyte salt, a gel electrolyte in which a matrix polymer is impregnated with a plasticizer composed of a non-aqueous solvent and an electrolyte salt, and the like. it can.

As an electrolyte salt contained in the solid electrolyte 9
Is a well-known lithium battery that is commonly used in non-aqueous battery electrolytes.
Um salts and the like can be used. Specifically, LiP
F₆, LiBF_Four, LiAsF₆, LiClO_Four, Li
CF_ThreeSO_Three, LiN (SO _TwoCF_Three)_Two, LiC (S
O_TwoCF_Three)_Three, LiAlCl_Four, LiSiF₆Etc.
Thallium salts can be used and these lithium salts
Use one kind or a mixture of two or more kinds. inside that
Also as a lithium salt, especially LiPF₆, LiBF_FourBut
It is desirable from the viewpoint of oxidative stability.

As the non-aqueous solvent, various non-aqueous solvents conventionally used for non-aqueous electrolytes can be used. For example, cyclic carbonic acid esters such as propylene carbonate and ethylene carbonate, chain carbonic acid esters such as diethyl carbonate and dimethyl carbonate, carboxylic acid esters such as methyl propionate and methyl butyrate, γ-butyl lactone, sulfolane, and 2-methyltetrahydrofuran. Ethers such as dimethoxyethane can be used. These non-aqueous solvents may be used alone or in combination of two or more. Among them, especially from the viewpoint of oxidation stability,
It is preferable to use a carbonate ester.

As the polymer solid electrolyte, both inorganic solid electrolytes and polymer solid electrolytes can be used as long as they are materials having lithium ion conductivity. Examples of the inorganic solid electrolyte include lithium nitride and lithium iodide. On the other hand, the polymer solid electrolyte is composed of the above-described electrolyte salt and a polymer compound that dissolves the electrolyte salt. As the polymer compound, for example, an ether polymer such as poly (ethylene oxide) or a cross-linked product thereof, a poly (methacrylate) ester polymer, an acrylate polymer, etc. may be polymerized alone or in the molecule, or mixed. Can be used.

As the matrix polymer of the gel electrolyte, various polymers can be used as long as they absorb the plasticizer in which the above-mentioned electrolyte salt is dissolved in the above-mentioned non-aqueous solvent and gelate. For example, poly (vinylidene fluorolide)
Or a fluoropolymer such as poly (vinylidene fluoride-co-hexafluoropropylene), an ether polymer such as poly (ethylene oxide) or a crosslinked product thereof, or
Nylon-based, urethane-based polymers, polyurea-based, polyacrylic acid derivatives, polymethacrylic acid derivatives, poly (acrylonitrile), cross-linked products having ether / ester / carbonate structures, etc., alone or in mixture. You can In particular, it is preferable to use a fluoropolymer because of its redox stability. Then, the gel electrolyte imparts ionic conductivity by containing an electrolyte salt.

The negative electrode 3 is formed by applying a negative electrode current collector 10 and a negative electrode mixture coating liquid containing a negative electrode active material on both main surfaces of the negative electrode current collector 10, drying and pressurizing. The formed negative electrode mixture layer 11 and a solid electrolyte solution similar to that used for the positive electrode 2 were applied to the negative electrode mixture layer 11, impregnated, and dried to form a layer on the negative electrode mixture layer 11. And the solid electrolyte 9. A metal foil such as copper is used for the negative electrode current collector 10.

The negative electrode mixture layer 11 contains a negative electrode active material doped / dedoped with lithium ions, a predetermined binder for binding the negative electrode active material to the negative electrode current collector 10, and the like.
And the negative electrode mixture layer 11 has 300 kgf / cm ^{2 to} 6
By pressure molding at a pressure in the range of 00 kgf / cm ^2, the volume of pores relative to the total volume is 25% to 35%.
Has been in the range.

At this time, when the negative electrode mixture layer 11 is pressure-formed at a pressure of less than 300 kgf / cm ² , the pressure is too small, so that the pore volume with respect to the total volume of the negative electrode mixture layer 11 is 35%. When the battery 1 is obtained, the amount of the negative electrode active material becomes small and the battery capacity becomes small. On the other hand, when the negative electrode mixture layer 11 is formed under pressure at a pressure higher than 600 kgf / cm ² , the pressure is too large, and the pore volume relative to the total volume of the negative electrode mixture layer 11 becomes smaller than 25%. Therefore, when the battery 1 is formed, the space for impregnating the negative electrode mixture layer 11 with the solid electrolyte 9 is reduced, and the electric resistance on the negative electrode 3 side is increased. Therefore, in the negative electrode mixture layer 11, the pressure for pressure formation is 300 kgf / cm ^{2 to} 600 kgf / cm.
The range is ² .

For the negative electrode active material, it is preferable to use lithium, a lithium alloy, or a carbon material that can be doped or dedoped with lithium. Examples of the carbon material that can be doped or dedoped with lithium include, for example, a low crystalline carbon material obtained by firing at a relatively low temperature of 2000 ° C. or lower, artificial graphite obtained by firing a raw material that easily crystallizes at a high temperature of around 3000 ° C., and the like. Highly crystalline carbon materials and the like can be used. Specifically, pyrolytic carbons, cokes, graphites,
A carbon material such as glassy carbon fiber, organic polymer compound fired body, carbon fiber or activated carbon can be used. The above cokes include pitch coke, needle coke,
There is petroleum coke, etc. Further, the above-mentioned organic polymer compound fired body refers to one obtained by firing a phenol resin, a furan resin or the like at an appropriate temperature to carbonize.

In addition to the above-mentioned carbon material, a polymer such as polyacetylene or polypyrrole or an oxide such as SnO ₂ can be used as a material that can be doped or dedoped with lithium. Further, as the lithium alloy, a lithium-aluminum alloy or the like can be used.

As the binder contained in the negative electrode mixture layer 11, a binder usually used in a positive electrode mixture of a battery can be used, and a conductive agent or the like can be used in the negative electrode mixture layer 11. Additives can be added.

As in the case of the positive electrode 2, the solid electrolyte 9 impregnated in the negative electrode mixture layer 11 is uniformly applied to the negative electrode mixture layer 11 and then left standing for a predetermined time. By doing so, 60% or more of the pore volume of the negative electrode mixture layer 11 is impregnated. At this time, when the amount of the solid electrolyte 9 impregnated in the pore volume of the negative electrode mixture layer 11 is less than 60% of the pore volume, the electric resistance on the negative electrode 3 side becomes large when the battery 1 is formed. Will end up. The impregnation amount of the solid electrolyte 9 with respect to the pore volume of the negative electrode mixture layer 11 is determined by the ratio of the pore volume to the total volume of the negative electrode mixture layer 11 when the amount of the applied solid electrolyte solution is constant. .

As the solid electrolyte 9 impregnated in the negative electrode mixture layer 11, the same solid electrolyte as that impregnated in the positive electrode mixture layer 8 described above can be used.

The battery 1 having the above-described structure has the positive electrode material mixture layer 8 and the negative electrode material mixture layer 11 each having a pore volume in the range of 25% to 35% with respect to the total volume thereof.
The solid electrolyte 9 is used in 60% or more of the pore volume of each of these.
The structure is impregnated with.

As a result, in the battery 1 to which the present invention is applied, the pore volume in the positive electrode mixture layer 8 and the negative electrode mixture layer 11 is in the range of 25% to 35% with respect to the total volume of each. The solid electrolyte 9 can be easily impregnated. Further, in the battery 1, since the solid electrolyte 9 is impregnated into 60% or more of the pore volume of each of the positive electrode mixture layer 8 and the negative electrode mixture layer 11, the positive electrode mixture layer 8 and the negative electrode mixture layer It is possible to improve the electrical contact between 11 and the solid electrolyte 9 and suppress the internal resistance of the battery.

Therefore, according to the present invention, the positive electrode mixture layer 8 and the negative electrode mixture layer 11 can be easily impregnated with the solid electrolyte 9 and the internal resistance of the battery is suppressed. A battery 1 having good battery characteristics such as characteristics can be obtained.

By the way, the positive electrode mixture layer 8 and the negative electrode mixture layer 1
When the pore volume with respect to each total volume of 1 is less than 25%, the solid electrolyte 9 impregnated into each pore volume of the positive electrode material mixture layer 8 and the negative electrode material mixture layer 11 decreases, and the positive electrode material mixture layer 8 and It becomes difficult to make good electrical contact between the negative electrode mixture layer 11 and the solid electrolyte 9. On the other hand, when the pore volume with respect to the total volume of each of the positive electrode mixture layer 8 and the negative electrode mixture layer 11 is larger than 35%, the electrode active material contained in each of the positive electrode mixture layer 8 and the negative electrode mixture layer 11 is The amount becomes small, and it becomes difficult to obtain an appropriate battery capacity.

Therefore, in the battery 1 to which the present invention is applied, the positive electrode material mixture layer 8 and the negative electrode material mixture layer 11 each have a pore volume in the range of 25% to 35% with respect to the total volume of the positive electrode material mixture layer 8 and the negative electrode material mixture layer 11. Between the positive electrode mixture layer 8 and the negative electrode mixture layer 11 and the solid electrolyte 9, the solid electrolyte 9 impregnated in the pore volumes of the mixture layer 8 and the negative electrode mixture layer 11 has an appropriate amount. The electrical contact can be improved. Further, in the battery 1, the positive electrode mixture layer 8 and the negative electrode mixture layer 1
Since the amount of the electrode active material contained in each of 1 is appropriate, the capacity can be increased.

When the solid electrolyte 9 is impregnated in the range of less than 60% with respect to the pore volume of each of the positive electrode mixture layer 8 and the negative electrode mixture layer 11, the positive electrode mixture layer 8 and the negative electrode are formed. The amount of the solid electrolyte 9 impregnated into each pore volume of the mixture layer 11 decreases, and it becomes difficult to improve the electrical contact between the positive electrode mixture layer 8 and the negative electrode mixture layer 11 and the solid electrolyte 9. Become.

Therefore, in the battery 1 to which the present invention is applied, the solid electrolyte 9 is impregnated into 60% or more of the pore volume of each of the positive electrode mixture layer 8 and the negative electrode mixture layer 11, so that By improving the electrical contact between the agent layer 8 and the negative electrode mixture layer 11 and the solid electrolyte 9 and suppressing the battery internal resistance, it is possible to improve battery characteristics such as large current discharge load characteristics and low temperature characteristics. it can.

The battery 1 to which the present invention having the above-mentioned structure is applied is manufactured as follows. When manufacturing the battery 1 to which the present invention is applied, first, the positive electrode 2 is manufactured.

In producing the positive electrode 2, first, a positive electrode mixture coating liquid containing a positive electrode active material made of a lithium composite oxide, a conductive agent, and a binder is applied from, for example, an aluminum metal foil or the like. The resulting positive electrode current collector 7 is evenly coated on both main surfaces, dried, and then pressure-molded at a predetermined pressure to form the positive electrode mixture layer 8. At this time, the positive electrode mixture layer 8 is 3
By pressurizing at a pressure in the range of 00 kgf / cm ^{2 to} 600 kgf / cm ² , the pore volume with respect to the total volume is in the range of 25% to 35%.

Next, a predetermined amount of lithium salt is dissolved in a non-aqueous solvent to prepare an electrolytic solution, and a predetermined amount of matrix polymer is added to this electrolytic solution and dissolved by heating to prepare a solid electrolyte solution. Next, this solid electrolyte solution is uniformly applied onto the positive electrode mixture layer 8 and left to stand for a predetermined time in order to impregnate the positive electrode mixture layer 8 with the solid electrolyte solution. Next, the solid electrolyte solution applied to the positive electrode mixture layer 8 is dried to form a layered solid electrolyte 9 on the positive electrode mixture layer 8.
At this time, the impregnated amount of the solid electrolyte 9 with respect to the pore volume of the positive electrode mixture layer 8 depends on the ratio of the pore volume to the total volume of the positive electrode mixture layer 8 when the amount of the applied solid electrolyte solution is constant. The positive electrode mixture layer 8 is impregnated with 60% or more of the pore volume of the positive electrode mixture layer 8.

As described above, the positive electrode 2 in which the solid electrolyte 9 is contained in the positive electrode mixture layer 8 is manufactured. As the conductive agent and the binder contained in the positive electrode mixture layer 8, a commonly used conductive agent and binder can be used, and an additive or the like may be added to the positive electrode mixture layer 8. it can.

Next, the negative electrode 3 is prepared. In producing the negative electrode 3, first, a negative electrode mixture coating liquid containing a carbon material serving as a negative electrode active material and a binder is applied to both main electrodes of the negative electrode current collector 10 made of, for example, a copper metal foil. The negative electrode mixture layer 11 is formed by evenly coating the surface and drying. At this time, the negative electrode mixture layer 11 is 300 kgf / cm ^{2 to} 600 kgf /
By pressure forming at a pressure in the range of cm ² ,
The pore volume with respect to the total volume is set in the range of 25% to 35%.

Next, the solid electrolyte solution used for producing the positive electrode 2 is uniformly applied on the negative electrode mixture layer 11, and the solid electrolyte solution is impregnated into the negative electrode mixture layer 11. To place. Next, the solid electrolyte solution applied to the negative electrode mixture layer 11 is dried to form the layered solid electrolyte 9 on the negative electrode mixture layer 11. At this time, the impregnation amount of the solid electrolyte 9 with respect to the pore volume of the negative electrode mixture layer 11 depends on the ratio of the pore volume to the total volume of the negative electrode mixture layer 11 when the amount of the applied solid electrolyte solution is constant. That is, 60% or more of the pore volume of the negative electrode mixture layer 11 is impregnated.

As described above, the negative electrode 3 in which the solid electrolyte 9 is contained in the negative electrode mixture layer 11 is manufactured. As the conductive agent and the binder contained in the negative electrode mixture layer 11, commonly used conductive agents and binders can be used, and additives and the like can be added to the negative electrode mixture layer 11. it can.

Next, using the press winding device 30 shown in FIG. 2, 5.0 kgf / cm ^{2 to} 30.0 kg of the obtained positive electrode 2 and negative electrode 3 are separated by a separator 4 made of a porous film.
By pressurizing at a pressure within the range of f / cm ² to laminate and integrate,
The battery element 5 is manufactured by winding a large number of spirals.

For example, the pressure for the lamination and integration is 5.0.
When it is smaller than kgf / cm ^2, the pressure for stacking and integrating the positive electrode 2 and the negative electrode 3 via the separator 4 is small, so that these stacked products cannot be integrated, and the positive electrode 2 and the negative electrode 3 are not integrated. It becomes difficult to reduce the electrical resistance between them. On the other hand, the pressure for stacking and integrating is 30.0 kgf
If it is larger than / cm ^2, the solid electrolyte 9 impregnated in each of the positive electrode 2 and the negative electrode 3 will exude due to the pressure of stacking and integration, and the electrical resistance between the positive electrode 2 and the negative electrode 3 will be reduced. Will be difficult.

As a result, in the press winding device 30, the pressure for laminating and integrating the positive electrode 2 and the negative electrode 3 via the separator 4 is 5.0 kgf / cm ^{2 to} 30.0 kgf / cm ^2.
By setting the above range, it is possible to prevent a gap from being generated between the positive electrode 2 and the negative electrode 3 and the separator 4, and to reduce the distance between the positive electrode 2 and the negative electrode 3 so that the positive electrode 2 and the negative electrode 3 are shortened.
It can be wound in a state of being laminated and integrated with the separator 4 interposed therebetween. Therefore, the electric resistance of the battery element 5 manufactured by the press winding device 30 is suppressed when the battery element 5 becomes the battery 1.

The press winding device 30 includes the positive electrode 2, the separator 4, and the separator 4 which are supplied from the supply rolls 31a to 31d.
In a state where the negative electrode 3 and the separator 4 are sequentially laminated, the negative electrode 3 and the separator 4 are drawn between the pair of press rolls 32a and 32b, and the pair of press rolls 32a and 32b are rotated to thereby remove the positive electrode 2, the separator 4, the negative electrode 3, and the separator 4. The positive electrodes 2 that are laminated and integrated in this order, and are laminated and integrated,
The negative electrode 3 and the plurality of separators 4 are wound around the winding shaft 33 in a spiral shape to produce the battery element 5.

When the battery element 5 is manufactured by the press winding device 30, first, the supply rolls 31a are supplied.
The positive electrode 2, the separator 4, the negative electrode 3, and the separator 4, which are supplied from 31 d to 31 d, are drawn in order between the pair of press rolls 32 a and 32 b in a state of being sequentially laminated. Next, the positive electrode 2, the negative electrode 3, and the plurality of separators 4 drawn in a state of being stacked on the pair of press rolls 32a and 32b are inserted between the supply rolls 31a to 31d and the winding shaft 33 by an arrow A in FIG.
While traveling in the direction indicated by, the pair of press rolls 32
The positive electrode 2, the separator 4, the negative electrode 3, and the separator 4 are pressure-bonded in this order by rotating and driving a and 32b in the direction shown by the arrow B in FIG. Next, the laminated positive electrode 2, negative electrode 3, and a plurality of separators 4
The winding shaft 33 winds up in a spiral shape. As described above,
The electronic element 5 is manufactured.

In the battery element 5 thus manufactured by the press winding device 30, it is possible to prevent a gap from being formed between the positive electrode 2 and the negative electrode 3 and the separator 4. When the positive and negative electrodes 2 and 3 are laminated and integrated by the press winding device 30 with the separator 4 interposed therebetween, the positive electrode 2 and the negative electrode 3 are interposed between the pair of rotating press rolls 32a and 32b.
It is performed by pulling in the negative electrode 3 and the plurality of separators 4 and pressure-bonding them, but the present invention is not limited to this. For example, the positive electrode 2 and the negative electrode 3 are interposed between a pair of rotating press rolls heated to a predetermined temperature. Alternatively, a plurality of separators 4 may be pulled in and thermocompression bonded.

Next, in the obtained battery element 5, one end of a positive electrode terminal 12 made of, for example, aluminum is joined to the positive electrode 2 and the negative electrode 3 is collected in order to collect the positive electrode 2. For this purpose, one end of the negative electrode terminal 13 made of nickel or the like is joined to the negative electrode 3.

Next, insulating plates 14a and 14b are installed on both end faces of the battery element 5 in a direction substantially orthogonal to the winding direction,
Battery element 5 with these insulating plates 14a, 14b installed
Are housed in a battery can 6 made of iron with nickel plated inside. Then, the other end portion of the positive electrode terminal 12 that is not joined to the positive electrode 2 is welded to the current interruption thin plate 15 to electrically connect to the battery lid 16 through the current interruption thin plate 15. As a result, the battery lid 16 becomes conductive with the positive electrode 2 and serves as an external positive electrode of the battery 1. It should be noted that the current interrupting thin plate 15 and the current are interrupted in accordance with the internal pressure of the battery. Further, the other end of the negative electrode terminal 13 which is not joined to the negative electrode 3 is welded to the battery can 6. As a result, the battery can 6 is
It becomes conductive with the negative electrode 3 and becomes an external negative electrode of the battery 1.

Next, the battery lid 16 is fixed by caulking the battery can 6 via the insulating sealing gasket 17 coated with asphalt. As described above, the cylindrical battery 1 is manufactured.

As shown in FIG. 1, the battery 1 is provided with a center pin 18 connected to the positive electrode terminal 12 and the negative electrode terminal 13, and when the internal pressure of the battery becomes higher than a predetermined value. A safety valve 19 for venting internal gas and a PTC (Positive Temperature Coefficient) element 20 for preventing temperature rise inside the battery
Is provided.

In the battery 1 obtained as described above, since the positive electrode 2 and the negative electrode 3 are laminated and integrated with the separator 4 interposed therebetween, a gap is generated between the positive electrode 2 and the negative electrode 3 and the separator 4. This is prevented and the distance between the positive electrode 2 and the negative electrode 3 is shortened, so that the internal resistance of the battery can be suppressed.

Therefore, in the method of manufacturing the battery 1,
Since the distance between the positive electrode 2 and the negative electrode 3 is shortened and the lithium ions are smoothly moved between the positive electrode 2 and the negative electrode 3,
The battery 1 with improved charge / discharge efficiency can be obtained. In the method of manufacturing the battery 1 to which the present invention is applied, the gap between the positive electrode 2 and the negative electrode 3 and the separator 4 is prevented from occurring, so that it is possible to improve the density of the battery element 5. The battery 1 having an improved battery capacity can be obtained.

Further, according to the method for manufacturing the battery 1, the pore volume of the positive electrode mixture layer 8 and the negative electrode mixture layer 11 is in the range of 25% to 35% with respect to the total volume of each, so that the solid mixture is solid. The battery 1 in which the electrolyte 9 is easily impregnated can be obtained. Therefore, according to the method for manufacturing the battery 1, since 60% or more of the pore volume of each of the positive electrode mixture layer 8 and the negative electrode mixture layer 11 is impregnated with the solid electrolyte 9, the positive electrode mixture layer 8 and the negative electrode mixture layer 11 and the solid electrolyte 9 have good electrical contact, and the battery 1 in which the battery internal resistance is suppressed can be obtained.

Therefore, in the method of manufacturing the battery 1, the positive electrode mixture layer 8 and the negative electrode mixture layer 11 can be easily impregnated with the solid electrolyte 9 and the internal resistance of the battery can be suppressed. The battery 1 having good battery characteristics such as low temperature characteristics can be obtained.

In the above-described embodiment, a solid electrolyte using a solid electrolyte containing an electrolyte salt or a gel electrolyte obtained by impregnating a matrix polymer with a non-aqueous solvent and an electrolyte salt is used as the non-aqueous electrolyte. However, the present invention is not limited to this, and is also applicable to a non-aqueous electrolytic solution prepared by dissolving an electrolyte salt in a non-aqueous solvent as the non-aqueous electrolyte. is there.

The battery to which the present invention is applied is not particularly limited in its shape such as a cylindrical shape, a rectangular shape, a coin shape, a button shape, and various sizes such as a thin shape and a large size. It is also possible to

[0074]

EXAMPLES Examples in which a lithium ion secondary battery to which the present invention is applied are actually manufactured will be described below. Also,
A comparative example prepared for comparison with these examples will be described.

Example 1 When the lithium-ion secondary battery in Example 1 was manufactured, first, the positive electrode was manufactured.
When manufacturing this positive electrode, first, Li was used as the positive electrode active material.
91 parts by weight of Mn ₂ O ₄ , 3 parts by weight of polyvinylidene fluoride resin (hereinafter referred to as PVDF) as a binder, 6 parts by weight of graphite as a conductive agent, and N-methyl-2- as a solvent. Pyrrolidone (hereinafter referred to as NMP) was added, and the mixture was kneaded and dispersed by a planetary mixer to prepare a positive electrode coating liquid.

Next, the obtained positive electrode coating liquid was uniformly applied to both main surfaces of a strip-shaped aluminum foil having a thickness of 20 μm to be a positive electrode current collector using a die coater as a coating device, and after drying. Then, the positive electrode material mixture layer was compression-molded by applying pressure with a roll press. At this time, the positive electrode mixture layer is 600 kgf / c
The void volume was set to 25% with respect to the total volume by pressure forming with m ² .

Next, 42.5 parts by weight of ethylene carbonate (EC) and 42.5 parts by weight of propylene carbonate (PC),
30 parts by weight of a plasticizer obtained by mixing 15 parts by weight of LiPF ₆ which is an electrolyte salt, 10 parts by weight of poly (vinylidene fluoride-co-hexafluoropropylene) which is a matrix polymer, and dimethyl carbonate 60 parts by weight were mixed and dissolved by heating to prepare a solid electrolyte solution.

Next, the obtained solid electrolyte solution was uniformly applied onto the positive electrode mixture layer and left standing for a predetermined time for impregnation. Next, dimethyl carbonate was vaporized and removed in a drying furnace to form a layered solid electrolyte on the positive electrode mixture layer. At this time, when the solid electrolyte is impregnated with the solid electrolyte solution in the positive electrode mixture layer, the solid electrolyte solution is coated on the positive electrode mixture layer and then left to stand for a predetermined time so that the positive electrode mixture layer has an empty space. The impregnation was made to 60% of the pore volume. The positive electrode was produced as described above.

Next, a negative electrode was prepared. When manufacturing this negative electrode, first, 90 parts by weight of graphite as a negative electrode active material, 10 parts by weight of PVDF as a binder, and NMP as a solvent were added, and kneading and dispersing were performed by a planetary mixer, A negative electrode coating liquid was prepared.

Next, the obtained negative electrode coating solution was uniformly applied to both main surfaces of a strip-shaped copper foil having a thickness of 20 μm to be a negative electrode current collector by using a die coater as a coating device and dried. Then, the negative electrode mixture layer was pressed by a roll press machine to be compression-molded. At this time, the negative electrode mixture layer was formed under pressure at 600 kgf / cm ² , so that the pore volume with respect to the total volume was 25%.

Next, a solid electrolyte solution similar to that for the positive electrode was uniformly applied on the negative electrode mixture layer, and left standing for a predetermined time for impregnation. Next, dimethyl carbonate was vaporized and removed in a drying furnace to form a layered solid electrolyte on the negative electrode mixture layer. At this time, as with the positive electrode, the solid electrolyte is impregnated into 60% of the pore volume of the negative electrode mixture layer by applying the solid electrolyte solution on the negative electrode mixture layer and then leaving it to stand for a predetermined time. I chose The negative electrode was produced as described above.

Next, by using a press winding device, the obtained positive electrode and negative electrode were laminated and integrated by pressurizing at 5.0 kgf / cm ² through a separator made of a polyethylene microporous film, and then swirling. A battery element was manufactured by winding it in a number of times.

Specifically, when manufacturing a battery element using a press winding device, first, a pair of press rolls in a state where a positive electrode, a separator, a negative electrode, and a separator supplied from a plurality of supply rolls are sequentially laminated. By pulling between the positive electrode, the negative electrode and a plurality of separators while running between the respective supply rolls and the winding shaft, by rotationally driving a pair of press rolls, the positive electrode, the separator,
Apply pressure to the negative electrode and separator in this order at 5.0 kgf /
It was pressure-bonded as cm ² , and laminated and integrated. Next, the positive electrode, the negative electrode, and the plurality of separators, which are laminated and integrated, are wound into a spiral winding shaft. The electronic device was manufactured as described above.

Next, in the obtained battery element, in order to collect the positive electrode, one end of a positive electrode terminal made of aluminum was joined to the positive electrode, and in order to collect the negative electrode,
One end of a nickel negative electrode terminal was joined to the negative electrode.

Next, an insulating plate is provided on each of both end surfaces of the battery element in a direction substantially orthogonal to the winding direction, and the battery element provided with the insulating plate is made of an iron battery can with a nickel plating inside. Stored in. Then, the other end of the positive electrode terminal, which is not joined to the positive electrode, is welded to a current interrupting thin plate, electrically connected to the battery lid through this current interrupting thin plate, and bonded to the negative electrode of the negative electrode terminal. The other end side, which was not present, was welded to the battery can.

Next, the battery lid was fixed by caulking the battery can through the insulating sealing gasket coated with asphalt. As described above, the diameter is 18 mm and the height is 65.
A mm-shaped cylindrical lithium ion secondary battery was produced. In the following description, the lithium-ion secondary battery is simply referred to as a battery for convenience.

<Example 2> In Example 2, the pressure for forming the positive electrode mixture layer and the negative electrode mixture layer under pressure was 300 kgf /
A battery was produced in the same manner as in Example 1 except that a positive electrode and a negative electrode each having a void volume of 35% with respect to the total volume of each mixture layer were produced as cm ² .

Example 3 In Example 3, when the positive electrode mixture layer and the negative electrode mixture layer were impregnated with the solid electrolyte solution, 70% of the pore volume of each mixture layer was impregnated with the solid electrolyte. A battery was produced in the same manner as in Example 1 except that the positive electrode and the negative electrode thus prepared were produced.

Example 4 In Example 4, when the positive electrode mixture layer and the negative electrode mixture layer were impregnated with the solid electrolyte solution, 90% of the pore volume of each mixture layer was impregnated with the solid electrolyte. A battery was produced in the same manner as in Example 1 except that the positive electrode and the negative electrode thus prepared were produced.

Example 5 In Example 5, when the positive electrode mixture layer and the negative electrode mixture layer were impregnated with the solid electrolyte solution, 100% of the pore volume of each mixture layer was impregnated with the solid electrolyte. A battery was produced in the same manner as in Example 1 except that the positive electrode and the negative electrode thus prepared were produced.

Comparative Example 1 In Comparative Example 1, the pressure for forming the positive electrode mixture layer and the negative electrode mixture layer under pressure was 700 kgf /
A battery was produced in the same manner as in Example 1 except that a positive electrode and a negative electrode each having a void volume of 20% with respect to the total volume of each mixture layer as a cm ² were produced.

<Comparative Example 2> In Comparative Example 2, the pressure for forming the positive electrode mixture layer and the negative electrode mixture layer under pressure was 200 kgf /
A battery was produced in the same manner as in Example 1 except that the positive electrode and the negative electrode each having a void volume of 40% with respect to the total volume of each mixture layer were produced as cm ² .

Comparative Example 3 In Comparative Example 3, when the positive electrode mixture layer and the negative electrode mixture layer were impregnated with the solid electrolyte solution, 50% of the pore volume of each mixture layer was impregnated with the solid electrolyte. A battery was produced in the same manner as in Example 1 except that the positive electrode and the negative electrode thus prepared were produced.

<Comparative Example 4> In Comparative Example 4, a positive electrode, a negative electrode and a plurality of separators which are not laminated and integrated by pressure are wound by pressurization without using a press winding machine when producing a battery element. A battery was manufactured in the same manner as in Example 1 except that the battery element was manufactured.

Next, with respect to the batteries of Examples 1 to 5 and Comparative Examples 1 to 4 produced as described above, the discharge capacity and the capacity retention rate at 2C discharge were measured.

The initial charging conditions were set such that the charging current was 0.5 CmA, which is the rated capacity, and the charging voltage was 4.2 V, and the charging was carried out at a constant current and constant voltage for 5 hours in an atmosphere of 23 ° C. The initial discharge conditions were set so that the discharge current was set to 1 CmA, which is the rated capacity, in the atmosphere of 23 ° C., and discharge was performed up to the discharge end voltage of 3.0 V. The charging and discharging conditions for the second and subsequent times were set to charge and discharge in the same manner as the initial charging and discharging conditions, except that the charging current was 1 CmA, which is the rated capacity.

The discharge capacities in Examples 1 and 2 as well as Comparative Examples 1 and 2 in which the state of the pore volume with respect to the total volume of each of the positive electrode mixture layer and the negative electrode mixture layer were compared, Table 1 shows the evaluation results of the capacity retention rate during 2C discharge.

[0098]

[Table 1]

In Table 1, the discharge capacity indicates the second discharge capacity. In addition, the capacity retention ratio during 2C discharge indicates the ratio of the discharge capacity when the discharge current is discharged to the discharge end voltage of 3.0V with the discharge current being 2CmA of the rated capacity, with respect to the second discharge capacity.

From the evaluation results shown in Table 1, Example 1 and Example 2 in which the pore volume in the positive electrode mixture layer and the negative electrode mixture layer were in the range of 25% to 35% with respect to each total volume
Then, the discharge capacity and the discharge capacity retention rate at the time of 2C discharge were higher than those of Comparative Example 1 in which the pore volume of the positive electrode mixture layer and the negative electrode mixture layer was 20% with respect to each total volume,
It can be seen that the battery characteristics such as charge / discharge efficiency characteristics and large current load characteristics are improved.

Comparative Example 1 in which the positive electrode mixture layer and the negative electrode mixture layer each have a void volume of 20% with respect to the total volume of each.
Then, in the positive electrode mixture layer and the negative electrode mixture layer, the pore volume with respect to the total volume of each is small, the solid electrolyte impregnated in the pore volume of each of the positive and negative electrodes is reduced, and the positive electrode mixture layer and the negative electrode mixture layer It becomes difficult to make good electrical contact with the solid electrolyte.

On the other hand, in the positive electrode material mixture layer and the negative electrode material mixture layer, the pore volume with respect to each total volume is 25% to 35%.
In Example 1 and Example 2 in which the content of the positive electrode material mixture layer and the negative electrode material mixture layer are within the appropriate range, the pore volume relative to the total volume of each of the positive electrode material mixture layer and the negative electrode material mixture layer is set to an appropriate range. The amount of the solid electrolyte impregnated into each void volume of the layer becomes appropriate, and good electrical contact can be achieved between the positive electrode mixture layer and the negative electrode mixture layer and the solid electrolyte. Therefore, in Example 1 and Example 2, the battery characteristics such as charge / discharge efficiency characteristics and large current load characteristics can be made better than Comparative Example 1.

Further, from the evaluation results shown in Table 1, in Example 1 and Example 2 in which the pore volume of the positive electrode mixture layer and the negative electrode mixture layer was in the range of 25% to 35% with respect to each total volume. The discharge capacity and the discharge capacity retention rate at 2C discharge are higher than those of Comparative Example 2 in which the pore volume of the positive electrode mixture layer and the negative electrode mixture layer is 40% with respect to the total volume of the positive electrode mixture layer and the negative electrode mixture layer. It can be seen that the battery characteristics such as and high current load characteristics are improved.

Comparative Example 2 in which the positive electrode material mixture layer and the negative electrode material mixture layer each had a void volume of 40% with respect to each total volume.
Then, in the positive electrode mixture layer and the negative electrode mixture layer, the pore volume with respect to each total volume is large, and since the amount of the electrode active material contained in each of the positive electrode mixture layer and the negative electrode mixture layer is small, It becomes difficult to obtain an appropriate battery capacity.

On the other hand, in the positive electrode material mixture layer and the negative electrode material mixture layer, the void volume relative to the total volume of each is 25% to 35%.
In Example 1 and Example 2 in which the content of the positive electrode material mixture layer and the negative electrode material mixture layer are within the appropriate range, the pore volume relative to the total volume of each of the positive electrode material mixture layer and the negative electrode material mixture layer is set to an appropriate range. A high capacity battery can be obtained by appropriately adjusting the amount of the electrode active material contained in each of the layers. Therefore,
In Example 1 and Example 2, the battery characteristics such as charge / discharge efficiency characteristics and large current load characteristics can be made better than Comparative Example 2.

From the above, when the battery is manufactured, it is necessary to set the pore volume of the positive electrode mixture layer and the negative electrode mixture layer in the range of 25% to 35% with respect to the total volume of each of the positive electrode mixture layer and the negative electrode mixture layer. It is very effective in producing batteries with good battery characteristics such as high current load characteristics.

Next, Example 1 and Examples 3 to 5 comparing the impregnated states of the solid electrolyte impregnated in the respective pore volumes of the positive electrode mixture layer and the negative electrode mixture layer, and the comparison Table 2 shows the evaluation results of the discharge capacity and the capacity retention rate at 2 C discharge in Example 3.

[0108]

[Table 2]

The evaluation criteria for each item in Table 2 are the same as those in Table 1 described above. In addition, Example 1
And in Examples 3 to 5 and Comparative Example 3,
The impregnation rate of the solid electrolyte impregnated into the respective pore volumes of the positive electrode mixture layer and the negative electrode mixture layer, the discharge capacity, and 2
FIG. 3 shows the relationship with the capacity retention rate during C discharge. In FIG. 3, the horizontal axis represents the solid electrolyte impregnation rate, the vertical axis represented by S1 represents the discharge capacity, and the vertical axis represented by S2 represents the capacity retention rate at 2C discharge, and each measurement point of the discharge capacity is indicated by a triangle mark. Shows,
Each measuring point of the capacity retention rate at 2C discharge is indicated by a circle.

From the evaluation results shown in Table 2, Example 1 and Examples 3 to 5 in which 60% or more of the pore volume of each of the positive electrode mixture layer and the negative electrode mixture layer are impregnated with the solid electrolyte are shown. The discharge capacity and the discharge capacity retention rate at 2C discharge were higher than those of Comparative Example 3 in which 50% of the pore volume of each of the positive electrode mixture layer and the negative electrode mixture layer was impregnated with the solid electrolyte. It can be seen that battery characteristics such as efficiency characteristics and large current load characteristics are improved.

Further, when comparing Example 1 and Examples 3 to 5 with Comparative Example 3 from FIG. 3, 60% of the pore volume of each of the positive electrode material mixture layer and the negative electrode material mixture layer is 60%. It can be seen that if the solid electrolyte is impregnated beyond the range, a high discharge capacity and a good capacity retention rate during 2C discharge can be obtained.

In Comparative Example 3 in which the solid electrolyte to be impregnated in each of the pore volumes of the positive electrode mixture layer and the negative electrode mixture layer was 50%, the positive electrode mixture layer and the negative electrode mixture layer each had Since the amount of the solid electrolyte impregnated with respect to the pore volume is small, it becomes difficult to make good electrical contact between the positive electrode mixture layer and the negative electrode mixture layer and the solid electrolyte.

On the other hand, the solid electrolyte to be impregnated in each of the pore volumes of the positive electrode mixture layer and the negative electrode mixture layer was
In Example 1 and Examples 3 to 5 in which the content is 0% or more, the amount of the solid electrolyte to be impregnated is appropriate for each pore volume of the positive electrode mixture layer and the negative electrode mixture layer,
It is possible to improve the electrical contact between the positive electrode material mixture layer and the negative electrode material mixture layer and the solid electrolyte, and suppress the internal resistance of the battery. Therefore, in Example 1 and Examples 3 to 5, the battery characteristics such as charge / discharge efficiency characteristics and large current load characteristics can be made better than Comparative Example 3.

From the above, when manufacturing a battery, it is necessary to impregnate 60% or more of the pore volume of each of the positive electrode material mixture layer and the negative electrode material mixture layer with the solid electrolyte, which means that charge and discharge efficiency characteristics and It is very effective in producing a battery having good battery characteristics such as large current load characteristics.

Next, the evaluation results of discharge capacity and capacity retention ratio at 2C discharge in Example 1 and Comparative Example 4 in which the presence and absence of the positive electrode and the negative electrode laminated and integrated through the separator were compared are shown. 3 shows.

[0116]

[Table 3]

The evaluation criteria for each item in Table 3 are the same as those in Table 1 above.

From the evaluation results shown in Table 3, in Example 1 in which the battery element in which the positive electrode and the negative electrode were pressed through the separator to be laminated and integrated and wound, the discharge capacity and the discharge at 2C discharge were used. The capacity retention rate is higher than that of Comparative Example 4 using a battery element in which a positive electrode and a negative electrode are not laminated and integrated by pressure via a separator, and the battery has charge / discharge efficiency characteristics and large current load characteristics. It can be seen that the characteristics are greatly improved.

In Comparative Example 5 in which the positive electrode and the negative electrode are not laminated and integrated by pressure via the separator, a gap is generated between the positive electrode and the negative electrode and the separator, and the distance between the positive electrode and the negative electrode is large. As a result, the internal resistance increases, and it becomes difficult to move lithium ions smoothly, and the charge / discharge efficiency decreases.

On the other hand, in Example 1 in which the positive electrode and the negative electrode are laminated and integrated by applying pressure through the separator, a gap is prevented from being formed between the positive electrode and the negative electrode, and the positive electrode and the negative electrode are separated. Since the distance between them decreases, the internal resistance of the battery can be suppressed. In Example 1, the distance between the positive electrode and the negative electrode was shortened,
Since lithium ions move smoothly between the positive electrode and the negative electrode, the charge / discharge efficiency can be improved.
Furthermore, in Example 1, since a gap is prevented from being formed between the positive electrode and the negative electrode, and the separator, it is possible to improve the density of the battery element and the battery capacity. Therefore, in Example 1,
The battery characteristics such as charge / discharge efficiency characteristics and large current load characteristics can be made better than in Comparative Example 4.

From the above, when manufacturing a battery, it is advantageous to press the positive electrode and the negative electrode together through the separator to integrate them into a laminated body, which has good battery characteristics such as charge / discharge efficiency characteristics and large current load characteristics. It is very effective in producing

[0122]

As is apparent from the above description, according to the present invention, in the positive electrode material mixture layer and the negative electrode material mixture layer, the pore volume with respect to each total volume is in the range of 25% to 35%. Therefore, the non-aqueous electrolyte can be easily impregnated. Further, according to the present invention, since the nonaqueous electrolyte is impregnated into 60% or more of the respective pore volumes of the positive electrode mixture layer and the negative electrode mixture layer, the positive electrode mixture layer and the negative electrode mixture layer are It is possible to improve the electrical contact with the non-aqueous electrolyte and suppress the internal resistance of the battery. Further, according to the present invention, the positive electrode and the negative electrode are laminated and integrated by being pressed through the separator, a gap is prevented from being generated between the non-aqueous electrolyte and the separator, and Since the distance between them is shortened, the charging / discharging efficiency can be improved. Further, according to the present invention, a gap is prevented from being formed between the non-aqueous electrolyte and the separator, and the positive electrode and the negative electrode are brought into close contact with each other to have a high density, so that the battery capacity can be improved. Therefore, according to the present invention, the ratio of the pore volume to the total volume of each of the positive electrode mixture layer and the negative electrode mixture layer, and the impregnation rate of the non-aqueous electrolyte with which the respective pore volumes are impregnated are controlled. Then, by stacking and integrating the positive electrode and the negative electrode via the separator, it is possible to obtain a battery having good battery characteristics such as large current discharge load characteristics, low temperature characteristics, charge / discharge efficiency characteristics, and battery capacity characteristics.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an internal structure of a battery according to the present invention.

FIG. 2 is a schematic side view showing a configuration example of a press winding device.

FIG. 3 is a characteristic diagram showing the relationship between the solid electrolyte impregnation ratio with respect to the respective pore volumes of the positive electrode mixture layer and the negative electrode mixture layer, and the discharge capacity and the capacity retention rate during 2C discharge.

[Explanation of symbols]

1 lithium-ion secondary battery, 2 positive electrode, 3 negative electrode, 4
Separator, 5 Battery element, 6 Battery can, 7 Positive electrode current collector, 8 Positive electrode mixture layer, 9 Solid electrolyte, 10 Negative electrode current collector, 11 Negative electrode mixture layer, 12 Positive electrode terminal, 13 Negative electrode terminal, 14a, 14b Insulation Plate, 15 thin plate for current interruption,
16 battery lid, 17 insulation sealing gasket, 18 center pin, 19 safety valve, 20 PTC element, 30 press winding device, 31a, 31b, 31c, 31d supply roll, 32a, 32b press roll, 33 winding shaft

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 5H029 AJ02 AJ06 AJ15 AK03 AK18                       AL02 AL06 AL07 AL08 AL12                       AL16 AM03 AM04 AM05 AM07                       AM12 AM16 BJ02 BJ14 CJ03                       CJ06 CJ07 CJ22 CJ23 HJ01                       HJ09                 5H050 AA02 AA06 AA12 BA15 CA08                       CA09 CA29 CB02 CB07 CB08                       CB09 CB12 CB20 DA02 DA03                       GA03 GA08 GA22 GA23 HA01                       HA09

Claims (10)

[Claims] 1. A positive electrode mixture layer containing a positive electrode active material is formed on a main surface of a positive electrode current collector, the positive electrode mixture layer is impregnated with a non-aqueous electrolyte, and the negative electrode active material is contained. A negative electrode mixture layer is formed on the main surface of the negative electrode current collector, and the negative electrode mixture layer is impregnated with the nonaqueous electrolyte, and a porous film interposed between the positive electrode and the negative electrode. In the positive electrode mixture layer and the negative electrode mixture layer, the pore volume with respect to each total volume is in the range of 25% to 35%, and 60% or more of each pore volume is A non-aqueous electrolyte battery impregnated with a non-aqueous electrolyte. 2. The non-aqueous electrolyte battery according to claim 1, wherein the positive electrode and the negative electrode are laminated and integrated via the separator by being pressed. 3. The non-aqueous electrolyte battery according to claim 1, wherein the non-aqueous electrolyte is an organic polymer compound containing a lithium salt and a non-aqueous solvent. 4. A positive electrode mixture layer containing a positive electrode active material is formed on the main surface of a positive electrode current collector, and the positive electrode mixture layer contains a positive electrode in which a non-aqueous electrolyte is impregnated, and a negative electrode active material. A negative electrode mixture layer is formed on the main surface of the negative electrode current collector, and the negative electrode mixture layer is impregnated with the nonaqueous electrolyte, and a porous film interposed between the positive electrode and the negative electrode. A non-aqueous electrolyte battery in which the positive electrode and the negative electrode are laminated and integrated via the separator by being pressed. 5. The non-aqueous electrolyte battery according to claim 4, wherein the non-aqueous electrolyte is an organic polymer compound containing a lithium salt and a non-aqueous solvent. 6. A first step of forming a positive electrode mixture layer containing a positive electrode active material on the main surface of a positive electrode current collector, and producing a positive electrode in which the positive electrode mixture layer is impregnated with a non-aqueous electrolyte, A second step of forming a negative electrode mixture layer containing a negative electrode active material on the main surface of a negative electrode current collector, and manufacturing a negative electrode in which the negative electrode mixture layer is impregnated with the non-aqueous electrolyte; And a third step of interposing a separator made of a porous film between the negative electrode and the negative electrode, wherein the first step and the second step include forming the positive electrode mixture layer and the negative electrode mixture layer, respectively. And forming the void volume with respect to the total volume of each of them in the range of 25% to 35%, and by adding 60% or more of the void volume of the positive electrode mixture layer and the negative electrode mixture layer to the non-water. A method for manufacturing a non-aqueous electrolyte battery in which an electrolyte is impregnated. 7. The method for producing a non-aqueous electrolyte battery according to claim 6, wherein in the third step, the positive electrode and the negative electrode are laminated and integrated by pressurizing via the separator. 8. The first step and the second step are:
The method for producing a non-aqueous electrolyte battery according to claim 6, wherein an organic polymer compound containing a lithium salt and a non-aqueous solvent is used as the non-aqueous electrolyte. 9. A first step of forming a positive electrode mixture layer containing a positive electrode active material on the main surface of a positive electrode current collector, and producing a positive electrode in which the positive electrode mixture layer is impregnated with a non-aqueous electrolyte, A second step of forming a negative electrode mixture layer containing a negative electrode active material on the main surface of a negative electrode current collector, and manufacturing a negative electrode in which the negative electrode mixture layer is impregnated with the non-aqueous electrolyte; And a third step in which the negative electrode and the negative electrode are laminated and integrated by pressurizing the negative electrode through a separator made of a porous film. 10. The production of a non-aqueous electrolyte battery according to claim 9, wherein in the first step and the second step, an organic polymer compound containing a lithium salt and a non-aqueous solvent is used in the non-aqueous electrolyte. Method.