JPH0760687B2 - Organic electrolyte battery - Google Patents

Description

TECHNICAL FIELD The present invention relates to an organic electrolyte battery including an anode to which a metal reducing agent is added, a cathode, and an electrolytic solution.

[Outline of Invention]

The present invention is an organic electrolyte battery comprising an anode to which a metal reducing agent is added, a cathode, and an electrolytic solution, a compound that reacts with the metal reducing agent in the electrolytic solution to generate a chelate compound (hereinafter, chelate It is intended to provide an organic electrolyte battery having no capacity loss by preventing an internal short circuit between the positive electrode and the negative electrode which occurs during storage of the organic electrolyte battery by blending the agent).

[Conventional technology]

Using lithium or a lithium alloy as the cathode active material, using an organic electrolyte solution as an electrolyte solution, a so-called organic electrolyte battery has a high energy density, excellent leakage resistance, less self-discharge, excellent storage stability, etc. In recent years, it has attracted particular attention as a battery excellent in various characteristics and has been widely put into practical use as a power source for memory backup of various small electronic devices such as electronic wrist watches and calculators.

However, since this type of organic electrolyte battery has an open circuit voltage after manufacture or a voltage at the beginning of discharge that is higher than the discharge flat voltage, when it is used as it is in various electronic devices, There is a risk of malfunction. Therefore, a method of preventing malfunction of an electronic device or the like is usually performed by performing constant load discharge of about several percent of the total discharge capacity on the manufactured organic electrolyte battery and removing the high voltage part in advance. . This method
It is a very good method because it does not affect the inside of the battery and can perform good processing, but it has the drawback of increasing the manufacturing cost of the battery due to the large number of steps such as constant load discharge. Have

On the other hand, a method has been proposed in which a simple metal such as zinc, aluminum, magnesium, tin, or an alloy thereof is added to the anode active material and the anode active material is reduced to remove the high voltage portion. This method is advantageous in terms of manufacturing cost because it is the same as the normal battery manufacturing process except that a metal reducing agent is added when the anode active material is mixed and manufactured.

[Problems to be solved by the invention]

However, when the high-voltage portion is removed by adding the above-mentioned metal reducing agent, there is a problem that a battery that causes capacity loss occurs during storage of the organic electrolyte battery. This is because a part of the metal reducing agent added along with the battery reaction in the anode is eluted into the electrolytic solution as metal ions, and the metal ions are reduced on the surface of the cathode and redeposited as metal. it is conceivable that. That is, the metal precipitate re-precipitated on the cathode surface continues to grow dendriticly with the passage of time, passes through the pores of the separator, and reaches the anode surface. Then, the metal precipitate reaching the surface of the anode causes an internal short circuit between both electrodes, resulting in a capacity loss.

Therefore, the present invention has been proposed to solve the above-mentioned conventional problems, and prevents an internal short circuit between a positive electrode and a negative electrode that occurs during storage of an organic electrolyte battery, and an organic electrolyte without capacity loss. It is intended to provide a battery.

[Means for solving problems]

The inventors of the present invention have earnestly studied to achieve the above-mentioned object, and as a result, by mixing a chelating agent in an electrolytic solution constituting an organic electrolyte battery to generate a chelate compound, an internal short circuit between a positive electrode and a negative electrode can be achieved. It has been found that can be prevented.

The present invention has been completed based on the above findings,
In an organic electrolyte battery comprising an anode to which a metal reducing agent is added, a cathode, and an electrolytic solution, a compound that reacts with the metallic reducing agent to form a chelate compound is blended in the electrolytic solution. It is a thing.

In the present invention, as the anode active material constituting the organic electrolyte battery, manganese dioxide, iron dioxide, titanium disulfide,
Molybdenum disulfide, carbon fluoride (CF _x ), copper oxide,
Molybdenum trioxide, lithium composite oxide (LiMO ₂ , M is Co
Represents a metal element such as. ), Etc., as long as they can be usually used as the anode active material.

On the other hand, as the cathode active material, in addition to lithium, a lithium aluminum alloy, an alloy of lithium and one or more of lead, tin, bismuth, cadmium, copper, iron and the like can be used.

The anode active material, a metal reducing agent is added for the purpose of removing the initial high-voltage portion, the added metal reducing agent, zinc, vanadium, manganese, chromium, iron,
Cadmium, indium, tin, lead, zirconium, titanium, lithium, sodium, potassium, magnesium,
Examples include one kind or a mixture of two or more kinds selected from aluminum, bismuth, cobalt, calcium and the like.
The amount of the metal reducing agent added to the positive electrode active material is preferably 0.5% by weight or more. When the amount of the metal reducing agent added is less than 0.5% by weight, the effect of adding the metal reducing agent cannot be expected.

As the electrolytic solution used in the organic electrolyte battery, a non-aqueous organic electrolyte in which a lithium salt is used as an electrolyte and which is dissolved in an organic solvent is used.

Here, as the organic solvent, esters, ethers, 3
Substituted-2-oxazolidinones and mixed solvents of two or more of these may be mentioned.

Examples of the esters include alkylene carbonate (ethylene carbonate, propylene carbonate, γ-butyl lactone, 2-methyl-γ-butyl lactone, etc.) and the like.

Examples of ethers include diethyl ether, cyclic ethers such as ethers having a 5-membered ring [tetrahydrofuran; substituted (alkyl, alkoxy) tetrahydrofuran such as 2-methyltrahydrofuran, 2,5-dimethyltetrahydrofuran, 2-ethyltetrahydrofuran, 2, 2'-
Dimethyltetrahydrofuran, 2-methoxytetrahydrofuran, 2,5-dimethoxytetrahydrofuran, etc .; dioxolane, etc.], ether having a 6-membered ring [1,4-dioxane, pyran, dihydropyran, tetrahydropyran],
Dimethoxyethane and the like can be mentioned.

Examples of 3-substituted-2-oxazolidinones include 3-alkyl-2-oxazolidinone (3-methyl-2-oxazolidinone, 3-ethyl-2-oxazolidinone, etc.), 3-cycloalkyl-2-oxazolidinone (3-cyclohexyl-2). -Oxazolidinone, etc.), 3-aralkyl-2-
Examples thereof include oxazolidinone (3-benzyl-2-oxozaridinone and the like) and 3-aryl-2-oxazolidinone (3-phenyl-2-oxazolidinone and the like).

Among them, propylene carbonate, ether having a 5-membered ring (particularly tetrahydrofuran, 2-methyltetrahydrofuran, 2-ethyltetrahydrofuran, 2,5-dimethoxytetrahydrofuran, 2-methoxytetrahydrofuran), 3-methyl-2-oxazolidinone and the like are preferable.

As the electrolyte, lithium perchlorate, lithium borofluoride, lithium phosphofluoride, lithium chloroaluminate, lithium halide, lithium trifluoromethanesulfonate and the like can be used, and lithium perchlorate and lithium borofluoride are preferable.

Examples of chelating agents to be mixed in the electrolytic solution include 8-hydroxyquinoline (oxine), diphenylthiocarbazone (dithizone), 2-carboxy-2′-hiddleoxy-
5'-sulfoform azylbenzene (Zincon), diethyldithiocarbamic acid, dimethylglyoxime and the like can be mentioned. It is preferable to select and use a suitable chelating agent depending on the kind of the metal reducing agent added to the anode active material. The amount of the chelating agent mixed in the electrolytic solution is preferably 0.1 to 10 w / v%. When the chelating agent is blended in an amount of 10 w / v% or more, the impedance and discharge capacity of the organic electrolyte battery are adversely affected, and the electrolyte may expand to cause leakage from the battery.

[Action]

By adding a metal reducing agent to the anode active material, the initial high voltage portion of the organic electrolyte battery can be removed.

When a metal reducing agent is added to the positive electrode active material and a chelating agent is added to the electrolytic solution, when the added metal is eluted into the electrolytic solution after the reaction in the desired anode, the metal ions are captured and chelated. It is possible to prevent the metal ions from precipitating as a compound and causing the internal short circuit of the battery to be reprecipitated as a metal, and to prevent the capacity loss due to the internal short circuit between the anode and the cathode.

〔Example〕

Hereinafter, specific examples of the present invention will be described with reference to the drawings, but it goes without saying that the present invention is not limited to the following examples.

Example 1 To 86 parts by weight of iron disulfide, 9 parts by weight of graphite as a conductive agent, 3 parts by weight of polytetrafluoroethylene as a binder, and 2 parts by weight of zinc as a metal reducing agent were added.
Anode pellets were produced by pressure molding by a predetermined method so as to have a predetermined diameter and height.

On the other hand, metallic lithium having a lithium-aluminum alloy layer was used as a cathode active material, and processed into a predetermined diameter and height to obtain a cathode pellet.

Next, a sample battery was prepared using the above anode pellet and cathode pellet. That is, as shown in FIG. 1, a cathode pellet (2) prepared in advance is spot-welded to a cathode can (1) made of nickel-plated stainless steel, and an electrolyte solution is further contained on the cathode pellet (2). A separator (3) made of polypropylene non-woven fabric is overlaid, and a polypropylene gasket (4) coated with asphalt on the surface is fitted and then the prepared anode pellet (5)
Is placed on top of it through the separator (3), and the anode can (6) made of stainless steel with nickel plating is put on the anode can (1) and the end is caulked and sealed to keep the airtightness inside the battery. Then, a 1.5V class sample battery having a diameter of 9.5 mm and a height of 2.7 mm was produced. As the electrolytic solution, 1% of lithium perchlorate was added to a solvent in which propylene carbonate and 1,2-dimethoxyethane were mixed at a volume ratio of 3: 2.
An organic electrolytic solution was used which was dissolved at a ratio of mol / l, and further 8-hydroxyquinoline (hereinafter referred to as oxine) was dissolved as a chelating agent at a ratio of 1 g in 100 ml of the electrolytic solution.

Example 2 A sample battery was prepared in the same manner as in Example 1 except that the proportion of oxine in the electrolytic solution was 0.2 g in 100 ml of the electrolytic solution.

Example 3 In Example 1 above, diphenylthiocarbazone was used instead of oxine as the chelating agent, and Example 1 was used otherwise.
A sample battery was prepared in the same manner as in.

Comparative Example 1 A sample battery was prepared in the same manner as in Example 1 except that the chelating agent was not added to the electrolytic solution of the organic electrolyte battery prepared in Example 1.

The sample batteries produced in Examples 1 to 3 and Comparative Example 1 were stored at room temperature for one month, and the number of defective batteries due to the internal short circuit of the batteries during that period was examined. The results are shown in Table 1.

As is clear from Table 1, in the organic electrolyte battery in which the chelating agent was added to the electrolytic solution, the occurrence of internal short circuit failure was not observed.

Example 4 To 86.9 parts by weight of manganese dioxide, 9.3 parts by weight of graphite as a conductive agent, 1.8 parts by weight of polytetrafluoroethylene as a binder, and 2 parts by weight of zinc as a metal reducing agent were added, followed by a predetermined method. Anode pellets were produced by pressure molding so as to have a predetermined diameter and height.

On the other hand, metallic lithium having a lithium-aluminum alloy layer was used as a cathode active material, and processed into a predetermined diameter and height to obtain a cathode pellet.

Next, using the above anode pellets and cathode pellets, having the same structure as in Example 1 above, a 3V having a diameter of 20 mm and a height of 2.5 mm was used.
-Grade sample batteries were prepared. As the electrolytic solution, 1% of lithium perchlorate was added to a solvent in which propylene carbonate and 1,2-dimethoxyethane were mixed at a volume ratio of 3: 2.
An organic electrolytic solution was used which was dissolved at a ratio of mol / l and further oxine was dissolved as a chelating agent at a ratio of 4 g in 100 ml of the electrolytic solution.

Example 5 To 88.7 parts by weight of manganese dioxide, 9.3 parts by weight of graphite as a conductive agent, 1.8 parts by weight of polytetrafluoroethylene as a binder, and 0.2 parts by weight of magnesium as a metal reducing agent were added, followed by a predetermined method. Anode pellets were produced by pressure molding so as to have a predetermined diameter and height.

On the other hand, metallic lithium having a lithium-aluminum alloy layer was used as a cathode active material, and processed into a predetermined diameter and height to obtain a cathode pellet.

Next, using the above-mentioned anode pellets and the anode pellets, having the same structure as in Example 1 above, a 3V having a diameter of 20 mm and a height of 2.5 mm was used.
-Grade sample batteries were prepared. As the electrolytic solution, 1% of lithium perchlorate was added to a solvent in which propylene carbonate and 1,2-dimethoxyethane were mixed at a volume ratio of 3: 2.
An organic electrolytic solution was used which was dissolved at a ratio of mol / l and further oxine was dissolved as a chelating agent at a ratio of 2 g in 100 ml of the electrolytic solution.

Comparative Example 2 A sample battery was manufactured by the same method as in Example 4 except that the chelating agent was not added to the electrolytic solution of the organic electrolyte battery manufactured in Example 4.

Comparative Example 3 A sample battery was prepared in the same manner as in Example 5, except that the chelating agent was not added to the electrolytic solution of the organic electrolyte battery prepared in Example 5.

The sample batteries prepared in Example 4, Example 5, Comparative Example 2, and Comparative Example 3 were stored at room temperature for one month, and the number of defective batteries due to internal short circuit of the batteries during that period was examined. The results are shown in Table 2.

As is clear from Table 2, in the organic electrolyte battery in which the chelating agent was added to the electrolytic solution, the occurrence of internal short circuit failure was not observed.

In each of the above-mentioned examples, it is suitable to capture the metal ion when eluted as a metal reducing agent and metal ion added to the anode active material for removing the steel voltage part of the organic electrolyte battery, and Although an example of the combination of the chelating agents that can be dissolved in the electrolytic solution used has been disclosed, any combination of the metal reducing agent and the chelating agent may be used as long as the same effect can be obtained.

〔The invention's effect〕

As is clear from the above description, the initial high voltage portion of the organic electrolyte battery can be removed by adding the metal reducing agent to the anode active material.

In addition, by adding a metal reducing agent to the anode active material and compounding a chelating agent in the electrolytic solution, the chelating agent dissolved in the electrolytic solution captures metal ions partially eluted after the reaction in the anode and chelate. It can be precipitated as a compound and can prevent the metal ions from being re-precipitated on the cathode surface as a metal, which causes an internal short circuit of the battery. This can eliminate the internal short circuit of the battery and prevent the capacity loss.

Therefore, it is possible to provide an organic electrolyte battery having a low open circuit voltage and excellent long-term reliability. In addition, the organic electrolyte battery of the present invention is advantageous in terms of productivity because it is sufficient to add a chelating agent to the electrolytic solution.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing a configuration example of an organic electrolyte battery. 1 …… Cathode can 2 …… Cathode pellet 3 …… Separator 4 …… Gasket 5 …… Anode pellet 6 …… Anode can

Claims (1)

[Claims] 1. An anode to which a metal reducing agent is added, a cathode,
An organic electrolyte battery comprising an electrolytic solution, wherein the electrolytic solution contains a compound that reacts with the metal reducing agent to generate a chelate compound.