JP2003045486A - Manufacturing method for non-aqueous electrolyte battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method for realizing high discharging voltages or large discharging capacities matching the excellent characteristics of a non-aqueous electrolyte battery such as a lithium ion secondary battery. SOLUTION: A composition which is expected to vaporize when dripping and impregnating the composition into an electrode laminated body 7 in a reduced pressure or a vacuum is beforehand included in a non-aqueous electrolyte (not shown in Fig.) in a larger mix ratio with the volume expected to vaporize increased. By dripping the non-aqueous electrolyte into the electrode laminated body 7 for a predetermined period of time, the predetermined composition is impregnated into the electrode laminated body 7 in a prescribed mix ratio.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for manufacturing a non-aqueous electrolyte battery.

[0002]

2. Description of the Related Art In recent years, portable electronic devices such as video cameras, electronic notebooks, and portable personal computers (portable personal computers) have become widespread, and such electronic devices have been improved in performance, size, weight, and portability. Although progress is being made, there is a strong demand for batteries that are used as power sources for such small electronic devices to be small, lightweight and have a large capacity. As a battery to be used, there is an increasing demand for a secondary battery that can be repeatedly used by recharging, instead of a primary battery that is disposable after discharging.

Conventionally, a secondary battery generally used as a secondary battery is a nickel cadmium (NiCd; NiCd) battery using an alkaline electrolyte or a lead storage battery.
However, in such a conventional secondary battery, the discharge voltage per cell is limited to about 1.2 [V], and various researches and developments have been conducted to further improve the discharge capacity and the output voltage. However, there is a feeling that the improvement of its performance is already reaching its limit, and by further improving the energy density of nickel cadmium batteries and lead storage batteries, we have achieved further compact, lightweight and large capacity characteristics. It is practically difficult to do. In addition, nickel-cadmium batteries, lead-acid batteries, etc. generally have a high self-discharge rate of 20% or more in one month at a normal temperature, and after being charged once, let them be used for a predetermined period and then start using them again. If so, the problem that the apparent discharge amount has decreased due to natural discharge, and that the additional charge is required before restarting use, and the management of the charge amount becomes complicated. There was a problem.

Therefore, by using a non-aqueous solvent for the electrolytic solution and a light metal such as lithium for the negative electrode, the discharge voltage can be increased to 3 [V] or more, and the energy density is increased by the high discharge voltage characteristic. A non-aqueous electrolyte secondary battery has been proposed which has an excellent characteristic that it can be increased and has a low self-discharge rate. More specifically,
A substance capable of doping / dedoping lithium ions such as lithium, a lithium alloy, carbon, or a carbon-based material is used as the negative electrode, and LiCo ₂ or Li _x N _{1 -y} Co _y O ₂ or LiMn is used as the positive electrode. A non-aqueous electrolyte secondary battery using a lithium composite oxide such as ₂ O ₄ has been proposed, and research and development on it have been promoted.

Such a so-called lithium-ion secondary battery, in addition to the portable electronic equipment such as the portable personal computer as described above, continues to store data such as an electronic wrist watch continuously used for a long time and a D-RAM. There is great expectation for demand as a power source for backing up various memory elements that are required to hold the memory for a long time, and a power source for electronic devices such as calculators, cameras, and radios in which long-term charge cycle life is important.

However, in such a lithium-ion secondary battery, metallic lithium or the like used for the negative electrode grows in a dendrite form due to repeated charging and discharging and comes into contact with the positive electrode, and as a result, a short circuit occurs inside the battery to shorten its service life. Was found to have a shortcoming, and it was difficult to put it into practical use. As a countermeasure against that,
A non-aqueous electrolytic secondary battery in which lithium is alloyed with another metal and this alloy is used as a negative electrode has been studied. However, also in this case, it has been found that there is a disadvantage that the alloy may become fine particles due to repeated charging and discharging, and the life may be shortened.

Therefore, two kinds of carbon raw materials having different calcination temperatures are prepared using mesophase carbon as a raw material, and the two kinds of carbon raw materials are mixed at a predetermined mixing ratio,
The present applicant has described a technique of using a method for producing a negative electrode active material which is a sintered body in an inert gas or vacuum after granulating and forming a molded body, for example, in Japanese Patent Application Laid-Open No. 09-306492. Proposed. According to this technique, a carbonaceous material can be used to produce a high-capacity negative electrode active material for a secondary battery. By using this negative electrode active material for a negative electrode, a high energy density and a long battery life can be obtained. A water electrolyte secondary battery can be realized.

By the way, a so-called coin-shaped or card-shaped thin battery has conventionally been mainly used as a backup power source for a memory element, and therefore a rated output of a current of 1 to 2 [mA] or more is required. Was unsuitable. However, with the recent progress in further miniaturization, thinning, and weight reduction of electronic devices, it has been desired to use a coin-shaped thin secondary battery as a main power source of an ultrathin portable personal computer, for example. This is a relatively large current for light electrical equipment or portable electronic equipment.
There has been a demand for the realization of a coin-shaped thin secondary battery capable of outputting a current pulse of [mA] or more.

[0009]

However, according to the technology of the lithium ion secondary battery proposed by the present applicant in, for example, Japanese Patent Laid-Open No. 09-306492, a high discharge voltage and a large discharge capacity can be achieved. However, there is a problem that the target discharge voltage and discharge capacity may not be achieved in some lithium ion secondary battery products manufactured in an actual manufacturing line. Also,
Using a positive electrode or a negative electrode or a non-aqueous electrolyte made of the above materials, the positive electrode and the negative electrode are laminated through a separator to produce a normal correct structure, but the discharge voltage of the product or In some cases, the discharge capacity was reduced by 10% or more from the target value.

Moreover, according to the conventional techniques and knowledge, the reason why the target discharge voltage and discharge capacity cannot be achieved despite the fact that the positive electrode and the negative electrode inside the battery are manufactured in the correct structure is as follows. It is unclear that the excellent characteristics originally possessed by the lithium ion secondary battery as described above could not be fully exhibited.

The present invention has been made in view of the above problems, and an object thereof is to provide a non-aqueous electrolysis device such as a lithium ion secondary battery having a high discharge voltage and a large discharge capacity corresponding to original excellent characteristics. It is an object of the present invention to provide a method for producing a non-aqueous electrolyte battery, which makes it possible to produce a liquid battery.

[0012]

According to the method of manufacturing a non-aqueous electrolyte battery of the present invention, an electrode laminate is formed by laminating a positive electrode and a negative electrode made of a material capable of inserting and extracting lithium through a separator. And a step of dripping the non-aqueous electrolyte solution into the electrode laminate to impregnate the non-aqueous electrolyte solution containing predetermined composition components in a predetermined prescribed mixing ratio, and sealing the electrode laminate in an outer container. A method for manufacturing a non-aqueous electrolyte battery comprising a step, wherein a composition ratio of composition components expected to be volatilized when the non-aqueous electrolyte solution is dropped and impregnated into the electrode laminate is higher than a specified mixing ratio. The non-aqueous electrolyte solution contained in, by dropping into the electrode laminate in a reduced pressure state or a vacuum state, after impregnating the electrode laminate with a predetermined composition component in a prescribed mixing ratio, the electrode laminate in an outer container It is to seal it.

In the method for producing a non-aqueous electrolyte battery according to the present invention, a composition component which is expected to be volatilized when dropped and impregnated in the electrode laminate in a reduced pressure state or a vacuum state is previously prepared in an amount corresponding to the volatilized amount. A large amount (high mixing ratio) of the non-aqueous electrolyte is included with a margin, and the non-aqueous electrolyte is actually added dropwise to the electrode laminate for a predetermined time to obtain a predetermined composition component. Is impregnated into the electrode laminate at a specified mixing ratio.

Here, the amount of the composition component that is expected to be volatilized when the non-aqueous electrolyte is dropped and impregnated into the electrode laminate is confirmed in advance by an experimental rule or a statistical empirical rule, and It is desirable to set the mixing ratio of the non-aqueous electrolyte solution to be dropped in accordance with the amount confirmed to be volatilized.

As the above-mentioned experimental rule, for example, various environmental conditions such as humidity and temperature of the production line of the non-aqueous electrolyte battery to be produced, and the same conditions as the composition components and the prescribed mixing ratio thereof are set. In the trial production line, we conducted an experiment in which the non-aqueous electrolyte was dropped onto the electrode laminate for a predetermined time to actually obtain a sufficient impregnation state, and by that experiment, how much of which composition component volatilized It is effective to confirm that the loss will occur.

Alternatively, non-aqueous electrolysis may also be performed based on empirical rules based on statistical data of occurrence records of defective composition components, defective mixing ratios, etc. in the past many types of non-aqueous electrolyte battery production lines or production lots. It is possible to confirm the types of composition components that volatilize when the liquid is dropped on the electrode laminate and the amount of the volatile components.

Further, the above non-aqueous electrolytic solution contains a mixed solvent of a cyclic carbonate and a chain carbonate, and LiPF ₆ , LiBF ₄ , LiCF ₃ SO ₃ and Li are used as electrolytes.
By containing any one of N (C _n F _{2n + 1} SO ₃ ) ₂ , it is possible to further improve the original characteristics of the non-aqueous electrolyte solution itself.

Further, the above non-aqueous electrolytic solution contains dimethyl carbonate as a chain carbonate in a mixed solvent in a volume fraction of 60% or more and 90% or less, whereby the original characteristics of the non-aqueous electrolytic solution itself are obtained. May be further improved.

In the above electrode laminate, the positive electrode is formed by using a composite compound containing lithium, and the negative electrode is made of lithium or a lithium alloy, or a material or a carbon-based material which can be combined with lithium and lithium. By forming at least one of them as an active material, it is possible to further improve the original characteristics of the electrode laminate itself.

Alternatively, in the above electrode laminate, the positive electrode is represented by the general formula LiMO ₂ (M is one or more transition metal elements selected from all transition metal elements),
The negative electrode may be formed using a composite oxide of lithium and a transition metal, and the negative electrode may be formed using a carbon-based material. As a binderless electrode structure formed by mixing the system materials in a prescribed mixing ratio, granulating, forming a molded body, and then self-sintering in an inert gas or vacuum Good. By doing so, the original characteristics of the non-aqueous electrolytic solution itself are further improved.

The above non-aqueous electrolyte battery may be a rechargeable secondary battery. Also,
Among such secondary batteries, particularly in a thin secondary battery such as a so-called coin-shaped battery, for example, the mixing ratio of the composition components of the non-aqueous electrolyte and the error in the liquid amount are smaller than those in the case of a cylindrical secondary battery or the like. The present invention is particularly effective for a thin primary battery or a thin secondary battery using a non-aqueous electrolyte solution, because the influence on the discharge characteristics and the like tends to appear remarkably.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a schematic structure of a coin-shaped lithium ion secondary battery manufactured by a method for manufacturing a non-aqueous electrolyte battery according to an embodiment of the present invention. This lithium ion secondary battery includes a positive electrode pellet (positive electrode) 1, a negative electrode pellet (negative electrode) 2, and a separator 3.
The positive electrode can 4, the negative electrode can 5, and the gasket 6 constitute a main part thereof.

As the positive electrode pellet 1, for example, LiCoO ₂ is used, and graphite powder is used as a conductive material.
And as a binder polytetrafluoroethylene (PTF
E) The positive electrode active material is formed using powder.
An aluminum net (not shown) as a current collector is in close contact with the surface of the positive electrode active material.

The negative electrode pellet 2 is prepared, for example, by mixing two kinds of carbonaceous materials having different roasting temperatures at a predetermined mixing ratio, granulating the mixture to prepare a molded body, and then self-processing in an inert gas or in a vacuum. It is desirable to use a negative electrode active material having a binder-free structure formed by sintering. This is because it is possible to further improve the original characteristics of the electrode laminate 7 itself. An aluminum net (not shown) as a current collector is in close contact with the surface of the positive electrode active material. However, it goes without saying that the present invention is not limited to this.

A separator 3 made of, for example, a microporous polypropylene film is interposed between the positive electrode pellet 1 and the negative electrode pellet 2.

The positive electrode pellet 1 and the negative electrode pellet 2 are laminated (overlapped) with the separator 3 interposed therebetween,
The main part of the electrode stack 7 is configured. The electrode laminated body 7 is impregnated with a non-aqueous electrolytic solution (not shown) containing a predetermined composition component in a predetermined prescribed mixing ratio.

The outer container 8 is constructed by assembling the positive electrode can 4 and the negative electrode can 5 and sealing the surrounding portion with a gasket 6 made of polypropylene, for example. In this outer container 8, the electrode laminate 7 impregnated with the non-aqueous electrolytic solution is housed. Negative electrode can 5 of this outer container 8
Is made of, for example, stainless steel, and the positive electrode can 4 is
For example, it is possible to stack a total of three layers of thin plates or foils of aluminum, stainless steel, and nickel. The outer shape of the outer container 8, in other words, the outer shape of the lithium ion secondary battery is, for example, 20 [m
m] and a height of 2.5 [mm], such as a so-called coin type or button battery type.

More specifically, the main part of the lithium ion secondary battery having the above structure is manufactured by the manufacturing method described below. That is, for example, the above-mentioned LiCoO ₂ can be obtained by mixing 1 mol of cobalt oxide (.), Which is a raw material of the positive electrode active material, and 0.5 mol of lithium carbonate, and firing the mixture in air at 900 ° C. for 5 hours. Then, 91 parts by weight of this LiCoO ₂ , 6 parts by weight of graphite powder, and 3 parts by weight of PTFE powder are mixed so as to be homogeneous, thereby producing a positive electrode active material. After filling 500 [mg] of this positive electrode active material and preforming,
An aluminum net as a current collector was placed on the surface of the positive electrode active material, and pressure molding was performed to obtain a diameter of 15.5 [mm],
A positive electrode pellet 1 having a height of 0.7 [mm] is produced.

For the negative electrode pellet 2, for example, two kinds of carbonaceous materials having different roasting temperatures as disclosed in Japanese Patent Application Laid-Open No. 09-306492 filed by the present applicant are mixed at a predetermined mixing ratio, After granulating and producing a molded body,
A negative electrode active material having a structure without a binder, which is formed by self-sintering in an inert gas or in a vacuum, is adhered with, for example, an aluminum net as a current collector. The negative electrode pellet 2 has, for example, a diameter of 15.6 [m
m], height 0.8 [mm], weight 180 [mg], so-called coin-shaped battery specifications are possible.

The separator 3 inserted between the positive electrode pellet 1 and the negative electrode pellet 2 has a thickness of, for example, 50 [μ
[m] composed of a microporous polypropylene film can be used.

The outer dimensions of the above-mentioned materials are 20 mm in diameter.
In manufacturing a coin-shaped lithium-ion secondary battery having a [mm] height and a height of 15.6 [mm], it is expected that it will volatilize when the electrode laminate 7 is dropped and impregnated in a reduced pressure state or a vacuum state. The composition components are contained in the non-aqueous electrolyte solution in a large amount (at a high mixing ratio) with a margin for the volatilized amount in advance, and the non-aqueous electrolyte solution is actually applied to the electrode laminate 7 for a predetermined time. It is possible to impregnate the electrode laminate 7 with a predetermined composition ratio by dripping over and impregnating it.

FIG. 2 shows a process of manufacturing a lithium ion secondary battery having the above-mentioned material and structure at 20 ° C.
In a working atmosphere of 1 mol / mol of LiPF ₆ as an electrolyte
In the case of using ethylene carbonate (EC) as a high-boiling-point solvent in 1 (liter), the conductivity (longitudinal axis) of the non-aqueous electrolyte solution with respect to the amount of addition of dimethyl carbonate (DMC) as a low-boiling-point solvent (horizontal axis). It shows the experimental results of measuring the (axis).

According to the results of this experiment, the maximum conductivity of the non-aqueous electrolyte in the prepared battery was that the composition ratio of dimethyl carbonate and ethylene carbonate was 7%.
It turns out that this is the case at 0:30. However, a non-aqueous electrolyte solution having a composition ratio (mixing ratio) of dimethyl carbonate and ethylene carbonate of 70:30 is dropped on the electrode laminate 7 and is allowed to stand for a predetermined time such as 100 minutes. Despite being impregnated, the conductivity of the non-aqueous electrolyte in the battery that is completed by impregnation with the non-aqueous electrolyte does not reach the maximum value as described above, and a remarkable decrease may occur. is there.

Regarding the cause of such a decrease in conductivity,
As a result of various experiments and consideration, the present inventors have found that in the process of dropping and impregnating the electrode laminate 7 with the non-aqueous electrolyte in a reduced pressure atmosphere or in a vacuum state, the composition components of the non-aqueous electrolyte are It was confirmed that the conductivity of the non-aqueous electrolytic solution of the finally obtained battery is decreased due to the particularly remarkable volatilization of the low melting point solvent.

That is, even if the mixing ratio of the composition components of the non-aqueous electrolytic solution to be dropped onto the electrode laminate 7 is set to 70:30 which is the optimum value at the time of impregnation, the non-aqueous electrolysis will be performed. In the process of actually dropping and impregnating the liquid into the electrode laminate 7, the low-melting point solvent evaporates by, for example, about 10%, so that the composition components of the non-aqueous electrolyte solution finally impregnated in the electrode laminate 7 are The mixing ratio deviates from the optimum value of 70:30 or a suitable value within the allowable error range centered on the optimum value, for example, 60:40 or 50:50.

Here, the non-aqueous electrolyte is actually used for the electrode laminate 7
In order to prevent the low-melting point solvent from volatilizing during the step of dropping and impregnating into the electrode, it is possible to take measures such as quickly impregnating the dropping and impregnating without taking time. In order to achieve a desired electromotive property by sufficiently spreading the temperature, a predetermined impregnation time such as 80 minutes or 100 minutes is required. Therefore, in order to prevent the low-melting point solvent from volatilizing, if the electrode laminate 7 is impregnated with the non-aqueous electrolyte in a short time such as 20 minutes, the impregnation rate of the non-aqueous electrolyte is 40%. However, it becomes impossible to achieve a sufficient impregnation rate of the non-aqueous electrolyte solution into the electrode laminate 7.

FIG. 3 shows 14.6 [kPa] (gauge pressure p
= -650 [mmHg]) in a reduced pressure atmosphere, the time spent for dripping and impregnating the non-aqueous electrolytic solution into the electrode laminate 7 (horizontal axis) and the non-aqueous electrolytic solution impregnation rate (vertical axis). It represents the experimental result of measuring the correspondence relationship with. In this experiment, the electrolyte impregnation rate was estimated based on the ratio between the volume of voids inside the battery and the liquid amount of the dropped (injected) non-aqueous electrolyte. It can be seen that the necessary and sufficient impregnation time (pressure reduction time) to obtain an electrolytic solution impregnation rate close to (100%) is 100 minutes or more. Therefore, the impregnation time must be at least 100 minutes or longer.

However, it is unavoidable that the low melting point solvent volatilizes while the non-aqueous electrolyte solution is impregnated into the electrode laminate 7 for 100 minutes or more. For example,
In the case of the lithium-ion secondary battery having the above-mentioned material and structure, the vacuum impregnation time (the time spent for dripping the non-aqueous electrolyte solution into the electrode laminate 7 in the reduced pressure atmosphere to impregnate it; As shown in FIG. 4, the relationship between the axis) and the volatilization rate of the low melting point solvent (vertical axis) is almost linear with the vacuum impregnation time, and the volatility rate of the low melting point solvent increases. The present inventors confirmed that they would go.

In the case of the experimental results shown in FIG. 4, at the time of vacuum impregnation time of 100 minutes, the volatilization rate of the low melting point solvent (the ratio of the volatilization loss to the whole non-aqueous electrolyte) is about 10.
%. That is, since dimethyl carbonate, which is a low melting point solvent, volatilizes (losses) about 10% of the entire non-aqueous electrolyte, the mixing ratio of the composition components is the best prescribed mixing ratio at which the maximum conductivity is obtained, 70:30. (Dimethyl carbonate is 70%) or significantly deviates from the area within the allowable error range around it, for example, 60:40
It becomes like. Due to this, the electrode laminate 7
The electrical conductivity of the non-aqueous electrolyte solution impregnated in will be lower than the target value.

FIG. 5 shows the experimental results of the transition of the mixing ratio of dimethyl carbonate and ethylene carbonate which changes due to such volatilization loss. From the experimental results shown in FIG. 5, the ratio of ethylene carbonate is 1 each time the ratio of dimethyl carbonate decreases by 10%.
You can see that it has increased by 0%.

Therefore, in the manufacturing method of the present embodiment, a low melting point solvent (dimethyl carbonate), which is a composition component which is expected to volatilize when dropped and impregnated into the electrode laminate 7 in a reduced pressure state or a vacuum state. In order to allow a large margin in advance by the amount of volatilization (10%), a prescribed mixing ratio of 70:30 (dimethyl carbonate 7
The mixing ratio is 80:20, which is higher than 0%: ethylene carbonate 30%). That is, the mixing ratio of dimethyl carbonate is set to 80%, the mixing ratio of ethylene carbonate is set to 20%, and they are contained in the non-aqueous electrolytic solution, and the non-aqueous electrolytic solution is actually used for a predetermined time (for example, By dropping and impregnating the electrode laminated body 7 over 100 minutes, the high-melting point solvent and the low-melting point solvent, which are predetermined composition components of the non-aqueous electrolyte, are impregnated at a prescribed mixing ratio of 70:30. It is possible to manufacture a lithium ion secondary battery having a high discharge voltage characteristic and a large discharge capacity characteristic corresponding to the originally excellent characteristics by including the electrode laminated body 7 formed as described above.

[Example] 1 mol of cobalt oxide (.), Which is a raw material of the positive electrode active material, and 0.5 mol of lithium carbonate were mixed and baked in air at 900 ° C for 5 hours to obtain LiCoO 2.
Got ₂ Further, 91 parts by weight of this LiCoO ₂ , 6 parts by weight of graphite powder, and 3 parts by weight of PTFE powder were mixed so as to be homogeneous to produce a positive electrode active material.

The positive electrode active material thus obtained was mixed with 50
0 [mg] was used to preform the outer shape, an aluminum net was placed on the surface as a current collector, and pressure molding was performed to obtain a diameter of 15.5 [mm] and a height of 0.7 [m.
m] of the positive electrode pellet 1 was produced.

On the other hand, two kinds of carbonaceous materials, which are mesophase carbons having different roasting temperatures, are mixed in a predetermined mixing ratio and granulated to prepare a molded body, which is then placed in an inert gas or in a vacuum. By self-sintering to form a negative electrode active material having a structure without a binder, and an aluminum net as a current collector is adhered to the surface of the negative electrode active material to have a diameter of 15.6 [m
m], a height of 0.8 [mm], and a weight of 180 [mg], a negative electrode pellet 2 having specifications corresponding to the shape of a coin-shaped battery was produced. Subsequently, the negative electrode pellet 2 was dropped into a negative electrode can 5 made of stainless steel and punched into a predetermined outer dimension.

In order to form the electrode laminate 7 having a structure in which the negative electrode pellets 2, the separator 3 and the positive electrode pellets 1 are laminated, a microporous polypropylene film having a thickness of 50 [μm] is formed on the upper surface of the negative electrode pellets 2. The separator 3 was placed. At this time, needless to say, the separator 3 and the negative electrode pellet 2 are not yet impregnated with the non-aqueous electrolyte. Then, a gasket 6 made of polypropylene was placed around the periphery of the negative electrode can 5 as a sealing packing material.

[0047] Subsequently, the volume mixing ratio of dimethyl carbonate in a solvent a volume mixing ratio of ethylene carbonate were mixed in 20% while 80%, further LiPF ₆
Is dissolved at a rate of 1 mol / l (liter) to prepare a non-aqueous electrolytic solution for dropping, which is placed in a negative electrode can 5 on which the negative electrode pellet 2 and the separator 3 are placed in an overlapping manner. , 14.6 [kPa] in a reduced pressure atmosphere for 100 minutes for dropwise addition to impregnate. At this time, it was confirmed from experimental rules or statistical empirical rules that dimethyl carbonate volatilized by about 10% in volume ratio when the electrode laminate 7 was dropped and impregnated in a reduced pressure atmosphere (prediction), as described above.
Therefore, the volume mixing ratio of dimethyl carbonate and ethylene carbonate in the non-aqueous electrolyte solution in the electrode laminate 7 finally obtained after the dropping and impregnation steps is 80:20 to 70: Change to 30.

Subsequently, the positive electrode pellets 1 are placed on the separator 3, the positive electrode can 4 is further covered thereon, and the combined portion of the positive electrode can 4 and the negative electrode can 5 is caulked.
The sealed outer container 8 is used.

The composition ratio of the non-aqueous electrolytic solution in the electrode laminate 7 finally obtained by the above manufacturing method is
A prescribed mixing ratio of 70: which can obtain the best characteristics.
30 can be managed. As a result, as shown in FIG. 6, the lithium ion secondary battery of this example was set to 4.0.
When a heavy load discharge experiment was conducted with charging at [V] and 5 [mA] for 24 hours and at a discharge current of 10 [mA] and an end voltage of 2.0 [V], the discharge end voltage was reached. The discharge capacity was about 22 [mAh], and it was confirmed that sufficient discharge characteristics satisfying the target value were achieved.

[Comparative Example 1] The structure and dimensions of the secondary battery were the same as those in the above-described example, and the negative electrode pellet 2 was used.
The volume mixing ratio of dimethyl carbonate and ethylene carbonate in the non-aqueous electrolytic solution dropped on the separator 3 is set to 90:10, and other specifications and steps are the same as those in the above-mentioned embodiment, and the lithium ion secondary A battery was manufactured. That is, in the case of Comparative Example 1,
The volume mixing ratio of dimethyl carbonate was set to 80% of that of the example.
90%, which is even higher than that.

As a result, after the volatilization loss of about 10% of dimethyl carbonate, the volume mixture ratio of dimethyl carbonate and ethylene carbonate of the non-aqueous electrolyte finally impregnated in the electrode laminate 7 was about 80:20. When a heavy load discharge experiment similar to that of the example was performed, the discharge capacity up to the discharge end voltage was about 19 [mAh], and the discharge characteristics were 13.5% or more compared to the case of the example. It was confirmed to be low.

[Comparative Example 2] The structure and dimensions of the secondary battery were the same as those in the above-described Example, and the negative electrode pellet 2 was used.
The volumetric mixing ratio of dimethyl carbonate and ethylene carbonate in the non-aqueous electrolytic solution dropped onto the separator 3 is set to 70:30, and other specifications and steps are the same as those in the above-mentioned embodiment, and the lithium ion secondary A battery was manufactured. That is, in the case of Comparative Example 2,
The volume mixing ratio of dimethyl carbonate was set to 80% of that of the example.
70%, which is 10% lower than this (this is the same value as the “specified mixing ratio 70%” of the non-aqueous electrolyte solution to be dropped in the conventional manufacturing method).

As a result, after the volatilization loss of about 10% of dimethyl carbonate, the volume mixing ratio of dimethyl carbonate and ethylene carbonate of the non-aqueous electrolyte finally impregnated in the electrode laminate 7 was about 60:40. When a heavy load discharge experiment similar to that of the example was conducted, the discharge capacity up to the discharge end voltage was about 20 [mAh], and the discharge characteristics were reduced by 10% or more compared with the case of the example. It has been confirmed that it has occurred.

[Comparative Example 3] The structure and dimensions of the secondary battery were the same as those in the above-mentioned Example, and the negative electrode pellet 2 was used.
The volume mixing ratio of dimethyl carbonate and ethylene carbonate in the non-aqueous electrolytic solution dropped on the separator 3 is set to 60:40, and other specifications and steps are the same as those in the above-mentioned embodiment, and the lithium ion secondary A battery was manufactured. That is, in the case of Comparative Example 3,
The volume mixing ratio of dimethyl carbonate was set to 80% of that of the example.
60%, which is 20% lower than the above.

As a result, after the volatilization loss of about 10% of dimethyl carbonate, the volume mixing ratio of dimethyl carbonate and ethylene carbonate of the non-aqueous electrolyte finally impregnated in the electrode laminate 7 was about 50:50. When a heavy load discharge experiment similar to that of the example is performed, the discharge capacity up to the discharge end voltage is about 18 [mAh], and the discharge characteristics are reduced by 18% or more as compared with the case of the example. It was confirmed.

As is clear from the results of comparison between the above example and Comparative Examples 1, 2, and 3, it is expected that the electrode laminate 7 will be volatilized when dropped and impregnated in the electrode laminate 7. The low-melting-point solvent dimethyl carbonate, which is a composition component, is added in advance to the non-aqueous electrolyte with a mixing ratio as high as 80%, with a 10% increase from the prescribed mixing ratio of 70% with a margin in advance. By mixing the non-aqueous electrolyte solution, the non-aqueous electrolyte solution is actually added dropwise to the electrode laminate 7 for a predetermined period of time to finally mix the composition ratio of the non-aqueous electrolyte solution with which the electrode laminate body 7 is impregnated. Is an optimum value of 70:30
The specified mixing ratio can be set. By managing the mixture ratio of the composition components to the optimum prescribed mixture ratio in this way, it is possible to realize a high discharge voltage and a large discharge capacity that match the original excellent characteristics as a lithium ion secondary battery. Becomes

The composition component of the non-aqueous electrolyte is not limited to the above-mentioned combination of dimethyl carbonate and ethylene carbonate having different boiling points. In addition to this, for example, when a lithium salt is dissolved in a solvent as an electrolyte, as a combination of solvents having different boiling points, for example, propylene carbonate, ethylene carbonate,
2-dimethoxyethane, γ-butyl lactone, diethyl ether, tetrahydrofuran, 2-methyl-tetrahydrofuran, 1,3-dioxolane, solfuran, acetonitrile, dimethyl carbonate, diethyl carbonate, dipropyl carbonate, methyl ethyl carbonate, methyl propyl carbonate, etc. It is possible to select and mix two or more kinds of composition components from the above.

As the non-aqueous electrolyte, for example, LiC
lO ₄ , LiAsF ₆ , LiPF ₆ , LiBF ₄ , Li
B (C ₆ H ₅ ), LiCl, LiBr, LiSO ₃ CH
₃ , LiSO ₃ CF ₃ , LiN (SO ₂ CF ₃ ) ₂ , L
It is possible to use iC (SO ₂ CF ₃ ) or the like.

Further, in the above-mentioned embodiment and examples,
I explained about the case of coin-shaped thin secondary battery,
In addition to the above, for example, a thin secondary battery in which an electrode laminated body is sealed in an outer container having a thin card shape or a thin casing shape in which a metal material is not a disc shape such as a coin, and the like can be manufactured by the present invention. The method is applicable. Alternatively, it goes without saying that the manufacturing method of the present invention can be applied to a lithium secondary battery used as a primary battery.

[0060]

As described above, according to the first to ninth aspects.
According to the method for producing a non-aqueous electrolyte battery according to any one of the above, a composition component that is expected to be volatilized when the non-aqueous electrolyte is dropped into the electrode laminate in a reduced pressure state or a vacuum state and impregnated is Preliminarily, a large amount of the volatilized amount is provided in advance, and the non-aqueous electrolytic solution is contained in the non-aqueous electrolytic solution at a high mixing ratio, and the non-aqueous electrolytic solution is actually dropped into the electrode laminate over a predetermined time. As a result, since the electrode laminate is impregnated with the predetermined composition components at the specified mixing ratio, the error and variation of the mixing ratio caused by the volatilization of the composition components are eliminated, and the original excellent characteristics are achieved. It is possible to manufacture a non-aqueous electrolyte battery having a correspondingly high discharge voltage and a large discharge capacity.

Further, according to the method for producing a non-aqueous electrolyte battery according to claim 2, the amount of the composition component which is expected to volatilize when the non-aqueous electrolyte solution is dropped and impregnated into the electrode laminate. Is confirmed in advance by an experimental rule or a statistical empirical rule, and the mixing ratio of the non-aqueous electrolyte to be dropped should be set in advance so that the amount of the composition component confirmed to be volatilized can be replenished. Therefore, it is possible to accurately grasp the amount of the composition component that is expected to be volatilized when the non-aqueous electrolytic solution is dropped and impregnated into the electrode laminate, and further, it is possible to volatilize the specific composition component. It is possible to more reliably eliminate the error or variation in the mixing ratio caused by the production, and it is possible to manufacture a non-aqueous electrolyte battery having a high discharge voltage and a large discharge capacity corresponding to the originally excellent characteristics.

Further, according to the method for producing a non-aqueous electrolyte battery of claim 3, the non-aqueous electrolyte contains a mixed solvent of a cyclic carbonate and a chain carbonate, and LiPF ₆ , LiBF ₄ , as an electrolyte, LiCF ₃ SO ₃ , LiN
By containing any one of (C _n F _{2n + 1} SO ₃ ) ₂ , the non-aqueous electrolyte solution is further improved in its original characteristics. The characteristics such as the original discharge voltage and discharge capacity of the battery can be further improved, and the characteristics can be derived very effectively by the invention according to claim 1. As a result, it is possible to realize a non-aqueous electrolyte battery having a high discharge voltage and a large discharge capacity.

Further, according to the method for producing a non-aqueous electrolyte battery of claim 4, dimethyl carbonate is used as the chain carbonate in the non-aqueous electrolyte, and the volume fraction of the dimethyl carbonate is 6 in the mixed solvent.
By containing 0% or more and 90% or less, the original characteristics of the non-aqueous electrolytic solution itself are further improved. Therefore, the characteristics such as the original discharge voltage and discharge capacity of the non-aqueous electrolytic cell are improved. Can be further improved, and it can be brought out very effectively, and as a result, it is possible to realize a non-aqueous electrolyte battery having a high discharge voltage and a large discharge capacity.

Further, according to the method of manufacturing a non-aqueous electrolyte battery of claim 5, the positive electrode is formed by using the composite compound containing lithium, and the negative electrode is lithium or a lithium alloy or lithium and lithium. By using at least one of a material that can be combined with a carbon-based material as an active material,
Since the original properties of the electrode laminate itself are further improved, good properties such as the original discharge voltage and discharge capacity of the non-aqueous electrolyte battery can be very effectively brought out, resulting in high It becomes possible to realize a non-aqueous electrolyte battery having a discharge voltage and a large discharge capacity.

Further, according to the method for producing a non-aqueous electrolyte battery according to claim 6, the positive electrode contains M as one or more kinds of transition metal elements selected from all transition metal elements.
It is formed by using iMO ₂ , and the negative electrode is formed by using a carbon-based material.
Since the original properties of the electrode laminate itself are further improved, good properties such as the original discharge voltage and discharge capacity of the non-aqueous electrolyte battery can be very effectively brought out, resulting in high It becomes possible to realize a non-aqueous electrolyte battery having a discharge voltage and a large discharge capacity.

Further, according to the method for producing a non-aqueous electrolyte battery of claim 7, two kinds of carbonaceous materials having different roasting temperatures are mixed in a predetermined mixing ratio for the negative electrode, granulated and molded. Further improve the intrinsic properties of the electrode stack itself by using an electrode structure that does not have a binder and is formed by self-sintering in an inert gas or vacuum after making the body. Therefore, the characteristics such as the original discharge voltage and discharge capacity of the non-aqueous electrolyte battery can be further improved, and the characteristics can be extremely effectively derived by the invention according to claim 1. As a result, a non-aqueous electrolyte battery having a high discharge voltage and a large discharge capacity can be realized.

Further, according to the method for producing a non-aqueous electrolyte battery according to claim 7 or 8, a rechargeable secondary battery, or among them, a thin secondary battery such as a coin-shaped battery, may be, for example, a cylinder. Since the influence of the mixing ratio of the composition components of the non-aqueous electrolytic solution and the error of the liquid amount on the discharge characteristics tends to appear remarkably more than in the case of the secondary battery of the shape described above, such a thin secondary battery is particularly preferable. By applying the technique of the present invention to, the occurrence of errors and variations in the mixing ratio due to volatilization of the composition components is eliminated, and a high discharge voltage and a large discharge capacity corresponding to the original excellent characteristics are provided. A non-aqueous electrolyte battery can be realized.

[Brief description of drawings]

FIG. 1 is a diagram showing a schematic configuration of a coin-shaped lithium ion secondary battery manufactured by a method for manufacturing a non-aqueous electrolyte battery according to an embodiment of the present invention.

FIG. 2 is a graph showing the conductivity of the non-aqueous electrolyte (vertical axis) with respect to the addition amount of dimethyl carbonate as a low boiling point solvent (horizontal axis) in the process of manufacturing the lithium-ion secondary battery having the structure shown in FIG. It is a figure showing the experiment result.

FIG. 3 shows the correspondence relationship between the time (horizontal axis) and the nonaqueous electrolytic solution impregnation rate (vertical axis) that are spent for dropping and impregnating a nonaqueous electrolytic solution into an electrode laminate in a reduced pressure atmosphere. It is a figure showing the measured experimental result.

FIG. 4 is a diagram showing an experimental result of measuring a relationship between a vacuum impregnation time (horizontal axis) and a volatilization rate of a low melting point solvent (vertical axis).

FIG. 5 is a diagram showing experimental results of changes in the mixing ratio of dimethyl carbonate and ethylene carbonate that change due to volatilization loss.

FIG. 6 is a graph showing that the lithium ion secondary batteries of Examples and Comparative Examples 1, 2, and 3 are charged at 4.0 [V] and 5 [mA] for 24 hours and terminated at a discharge current of 10 [mA]. The voltage is 2.
It is a figure showing the result of performing a heavy load discharge experiment as 0 [V].

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Positive electrode pellet, 2 ... Negative electrode pellet, 3 ... Separator, 4 ... Positive electrode can, 5 ... Negative electrode can, 6 ... Gasket, 7 ... Electrode laminated body, 8 ... Exterior container

Continued front page    (72) Inventor Kenichi Suzuki             Soni, 2 Hinoguchi, Motomiya-cho, Adachi-gun, Fukushima Prefecture             -In Fukushima Co., Ltd. (72) Inventor Yasuo Ota             Soni, 2 Hinoguchi, Motomiya-cho, Adachi-gun, Fukushima Prefecture             -In Fukushima Co., Ltd. F-term (reference) 5H029 AJ02 AJ03 AK03 AL06 AM03                       AM05 AM07 BJ03 BJ04 CJ13                       DJ09 HJ02 HJ10                 5H050 AA02 AA08 BA17 CA07 CA08                       CB07 DA02 DA03 EA09 GA02                       GA06 GA10 GA27 HA14

Claims (9)

[Claims] 1. A step of laminating a positive electrode and a negative electrode made of a material capable of inserting and extracting lithium through a separator to form an electrode laminated body, and dropping a non-aqueous electrolytic solution into the electrode laminated body. A method for producing a non-aqueous electrolyte battery comprising a step of impregnating a non-aqueous electrolyte containing a predetermined composition component at a predetermined prescribed mixing ratio, and a step of sealing the electrode laminate in an outer container, wherein A non-aqueous electrolyte containing a composition component that is expected to be volatilized when the non-aqueous electrolyte is dropped and impregnated into the electrode laminate at a mixing ratio higher than the specified mixing ratio, in a reduced pressure state or a vacuum state. Non-aqueous electrolysis, characterized in that the electrode composition is sealed in the outer container after the electrode composition is impregnated with the prescribed composition ratio in the electrode composition at a prescribed mixing ratio. Liquid battery manufacturing method. 2. The amount of the composition component predicted to be volatilized when the non-aqueous electrolyte is dropped and impregnated into the electrode laminate is confirmed in advance by an experimental rule or a statistical empirical rule, The method for producing a non-aqueous electrolyte battery according to claim 1, wherein the mixing ratio of the non-aqueous electrolyte solution to be dripped is set according to the amount of the non-aqueous electrolyte solution confirmed to be volatilized. 3. The nonaqueous electrolytic solution contains a mixed solvent of a cyclic carbonate and a chain carbonate, and L is used as an electrolyte.
iPF ₆ , LiBF ₄ , LiCF ₃ SO ₃ , LiN (C
_The method for producing a non-aqueous electrolyte battery according to claim 1, which contains any _{one of n} F _{2n + 1} SO ₃ ) ₂ . 4. The nonaqueous electrolytic solution contains dimethyl carbonate as the chain carbonate in a mixed solvent in a volume fraction of 6
The method for producing a non-aqueous electrolyte battery according to claim 3, wherein the content is 0% or more and 90% or less. 5. The positive electrode is formed using a composite compound containing lithium, and the negative electrode is at least one of lithium, a lithium alloy, a material capable of combining lithium and lithium, or a carbon-based material. The method for producing a non-aqueous electrolyte battery according to claim 1, which is formed by using any one of them as an active material. 6. The positive electrode is formed of a material of the general formula LiMO ₂ (M is one or more transition metal elements selected from all transition metal elements), and the negative electrode is a carbon-based material. The method for producing a non-aqueous electrolyte battery according to claim 1, which is formed using a material. 7. The negative electrode is prepared by mixing two kinds of carbonaceous materials having different roasting temperatures at a predetermined mixing ratio, granulating the mixture to prepare a molded body, and then performing self-treatment in an inert gas or in a vacuum. The method for producing a non-aqueous electrolyte battery according to claim 1, wherein the electrode structure has no binder and is formed by sintering. 8. The method for producing a non-aqueous electrolyte battery according to claim 1, wherein the non-aqueous electrolyte battery is a rechargeable secondary battery. 9. The method for producing a non-aqueous electrolyte battery according to claim 1, wherein the non-aqueous electrolyte battery is a thin battery or a thin secondary battery.