JP4913699B2 - Electrolytic capacitor - Google Patents

Description

The present invention relates to an electrolytic capacitor to be mounted on various electric and electronic devices. In particular, it relates to the prevention of the appearance of the electrolytic capacitor abnormality.

In general, an aluminum electrolytic capacitor is formed by etching a high-purity aluminum foil, an anode electrode foil having its surface anodized, and a cathode electrode foil having an aluminum foil etched so that electrolytic paper is interposed between these electrode foils. The wound capacitor element is impregnated with an electrolytic solution, and then the capacitor element is housed in an aluminum case and sealed with an elastic sealing member. Here, the electrolytic paper for an electrolytic capacitor is mainly composed of cellulose, hemicellulose, and lignin. Among these components, hemicellulose has a high reactivity and tends to decompose and generate gas (see, for example, Patent Document 1).
JP-A-9-213573

  In recent years, in order to reduce the size and weight of electronic devices, electronic components are also required to be smaller and lighter, and electrolytic capacitors are also being reduced in size. As a result, the excess space in the case becomes narrow, so if it is used for a long time under high temperature conditions, the appearance of gas such as the internal pressure will increase due to the generation of gas in the case and the explosion-proof valve will expand. It becomes easy. For this reason, the gas generated when the electrolytic paper reacts with the electrolytic solution to decompose the electrolytic paper also greatly affects the increase in internal pressure and the appearance defect.

  In addition, as a technology to suppress the increase in internal pressure, conventionally, a hydrogen gas absorbent such as a nitro compound has been used in the electrolyte, but the gas absorbed by the nitro compound is a reaction between the cathode electrode foil and the electrolyte. The nitro compound cannot be expected to absorb the decomposition gas of the electrolytic paper.

In view of the above problems, an object of the present invention is to provide suppress gas generation due to reaction with the electrolyte sheet, the electrolyte capacitor capable of preventing abnormal appearance such as explosion-proof valve expansion .

In order to solve the above problems, the engagement Ru electrolytic capacitor of the present invention, the solute in the solvent, xylanase, lignin peroxidase, blended least one enzyme selected from cellulases, whole electrolyte amount of enzyme Capacitor element impregnated with driving electrolytic solution and a plurality of electrode foils wound or laminated via electrolytic paper and being in a range of 0.1 to 10.0 wt% with respect to And a case for storing the capacitor element, wherein the capacitor element is impregnated with the driving electrolyte in a state where at least one of the capacitor element and the driving electrolyte is heated to 20 to 60 ° C. And

  According to the results of experiments conducted repeatedly by the inventors of the present application, when the electrolytic solution according to the present invention is used, the reaction between the electrolytic solution and the electrolytic paper is suppressed, and the generation of gas due to the decomposition of the electrolytic paper is suppressed and prevented. Can do. Therefore, according to the present invention, it is possible to suppress an increase in internal pressure and an appearance defect of the electrolytic capacitor.

  Enzymes used in the present invention are cellulose degrading enzymes, hemicellulose degrading enzymes, and lignin degrading enzymes. Each of these enzymes is a polymer degrading enzyme. Depending on the enzyme, the mode of action can be broadly divided into endo-type and exo-type, but any type of enzyme may be used in carrying out the present invention, and both types of enzymes may be used in combination. Also good.

  The enzyme is characterized by substrate specificity, working pH range, and working temperature range depending on its origin, but there are no particular limitations on the nature or origin of the enzyme in carrying out the present invention. The electrolytic paper to be treated can be used without distinction between natural fibers and regenerated cellulose fibers as long as the fibers can be used as electrolytic paper. In the case of natural fibers, there are no limitations on the freeness of the fibers, whether the pulp is bleached or unbleached, and whether wood pulp or specific wood pulp is used. In the case of regenerated cellulose, its production method, fiber diameter, and fiber length are not limited.

In the present invention, for example, the solvent is γ-butyrolactone or ethylene glycol, and the solute is at least a carboxylic acid and / or a salt thereof. In the solute, as the main solute, for example, an organic acid, an inorganic acid and / or a salt thereof can be used. Here, as the solute, carboxylic acids such as azelaic acid, adipic acid and 1,6-decanedicarboxylic acid, aromatic carboxylic acids such as benzoic acid, salicylic acid and phthalic acid, inorganic acids such as boric acid or salts thereof are used. be able to.
The solvent is a mixed solvent of ethylene glycol and γ-butyrolactone, water as a main solvent, glycols such as propylene glycol as a co-solvent, γ-butyrolactone, γ-valerolactone, δ-valerolactone, N- Lactones such as methyl-2-pyrrolidone, N-methylformamide, N, N-dimethylformamide, N-ethylformamide, N, N-diethylformamide, N-methylacetamide, N, N-dimethylacetamide, N-ethylacetamide Amides such as N, N-diethylacetamide and hexamethylphosphoric amide, carbonates such as ethylene carbonate, propylene carbonate and isobutylene carbonate, nitriles such as acetonitrile, oxides such as dimethyl sulfoxide, ethers, keto S, esters may be mixed sulfolane, etc., as the solute, improving the withstand voltage may be mixed with known additives for the purpose of suppressing such a gas generation.

In the present invention, the amount of the enzyme, area by (0.1~10.0wt%) der to 0.1wt% ~10.0wt% with respect to the total electrolyte. Although the amount of the enzyme depends on the type of enzyme, it is preferably within the above range from the viewpoint of effectively degrading the hemicellulose of the electrolytic paper regardless of the type, the type of solvent, and the like.
That is, when the amount of the enzyme is less than 0.1 wt%, the action of the enzyme on the electrolytic paper becomes insufficient and the effect is small. On the other hand, if it exceeds 10.0 wt%, the concentration of other solutes tends to decrease, leading to an increase in specific resistance.

In the present invention, when impregnated with the electrolyte in the capacitor element, often to warm at least one of the electrolyte or the capacitor elements, the temperature in this case has Mashiku is 20 to 60 ° C., particularly preferably Is 40-60 ° C. If one or more of the above enzymes are allowed to act in such a temperature range, the fiber can be treated.

  The present invention is characterized in that an enzyme is blended in the electrolytic solution, and the blending of the enzyme reduces the reaction between the electrolytic solution and the electrolytic paper and suppresses gas generation due to the decomposition of the electrolytic paper. Therefore, the electrolytic capacitor to which the present invention is applied has such an effect that the expansion of the explosion-proof valve is reduced over a long period of time in a high temperature atmosphere.

Examples of electrolytic capacitors according to the present invention will be described. Each of the following examples is an example in which the basic configuration is applied to an electrolytic capacitor having the most general winding structure. For this reason, although illustration and detailed description of the structure of the electrolytic capacitor are omitted, the electrolytic capacitor is generally manufactured by the following steps.

In producing the electrolytic capacitor of this example, first, the aluminum foil for the anode was subjected to an electrochemical etching treatment, and then anodized in a neutral or weakly acidic aqueous solution of an inorganic acid salt. Then, an oxide film is formed, and then a lead tab for drawing is attached to form an aluminum anode foil. On the other hand, the aluminum foil for cathode is etched, and a lead tab for drawing is attached to produce an aluminum cathode foil. Next, the anode foil, the cathode foil, and the electrolytic paper are overlapped and wound so that the electrolytic paper is interposed between the anode foil and the cathode foil, thereby producing a capacitor element.
Next, the capacitor element is impregnated with an electrolytic solution under heating, and then stored in a bottomed cylindrical aluminum case, and then the case opening is sealed with an elastic sealing body. Then, a rated voltage is applied to the capacitor in order to form the unformed part of the end face of the anode electrode foil with the electrolytic solution. In addition, you may implement the formation with respect to the unformed part of the end surface of the anode electrode foil used for the capacitor | condenser element before storing in a bottomed cylindrical aluminum case, after storing, or both.

  In the electrolytic capacitor manufactured by such a method, in the present invention, an electrolytic solution having the composition shown in Table 1 is used as the electrolytic solution.

Here, the main solvent of the electrolytic solution is a mixed solvent of ethylene glycol and water, and uses ammonium adipate as a solute. Of the electrolytic solutions shown in Table 1, Sample A is an electrolytic solution according to Conventional Example 1, and an electrolytic solution (samples C, D, E, F, H, I, J) containing an enzyme based on this composition. , K) is an electrolytic solution according to an example of the present invention, and an electrolytic solution (samples B and G) is an electrolytic solution according to a comparative example .

  In this example, an electrolytic solution having the composition shown in Table 2 was also examined in an electrolytic capacitor having the same structure as described above.

  In the electrolytic solution shown in Table 2, ethylene glycol is the main solvent and ammonium benzoate is the solute. Of the electrolytic solutions shown in Table 2, Sample L is an electrolytic solution according to Conventional Example 2, and an electrolytic solution (samples L, M, N, O, P, Q, R) containing an enzyme based on this composition. ) Is an electrolytic solution according to an example of the present invention.

Next, an electrolytic capacitor having a rating of 35 V to 1000 μF was produced using the electrolytic solutions of the conventional example , the comparative example, and the example shown in Table 1. In addition, electrolytic capacitors having a rating of 200 V to 100 μF were manufactured using the electrolytic solutions of the conventional examples and examples shown in Table 2. At that time, an aluminum case having an explosion-proof valve at the bottom was used. Such an explosion-proof valve bulges outward when the internal pressure of the capacitor rises, and further opens to release the gas when the internal pressure rises, thereby preventing the electrolytic capacitor from bursting.

  With these test capacitors, a rated DC voltage was applied for 5000 hours in a thermostat maintained at 105 ° C., and the valve expansion rate of the explosion-proof valve (the rate of increase in the length of the capacitor before and after the test) was investigated. The electrical characteristics after the test were measured. The results are shown in Tables 3 and 4. The electrical characteristics were measured by measuring the current (leakage current) flowing through the electrolytic capacitor at 20 ° C. after applying the electrostatic capacity at 120 Hz, tan δ, and the rated voltage for 1 minute.

  As can be seen from the results shown in Tables 3 and 4, the electrolytic capacitors using the conventional electrolytes (Samples A and L) are the expansion coefficient of the explosion-proof valve after 5000 hours in the load test in the 105 ° C. atmosphere. Is in the 105% range.

In contrast, electrolytic solution (samples B~K and sample M～R) a valve expansion of the explosion-proof valve after 5000 hours elapsed in the rated voltage application test of the electrolytic capacitor in 105 ° C. atmosphere using is reduced In comparison with the electrolytic capacitor using the conventional electrolytic solution (samples A and L), it was confirmed that the stability at high temperature was excellent.

  Therefore, according to the electrolytic capacitor using the electrolytic solution to which the present invention is applied, it is possible to prevent the appearance failure such as the expansion of the explosion-proof valve over a long period of time even when the surrounding parts generate heat. In addition, it is possible to obtain electrical characteristics equal to or higher than those obtained when a conventional electrolytic solution is used.

Further, as can be seen from a comparison of the respective examples, the effect of reducing the valve expansion rate of the explosion-proof valve is great when xylanase is used for the type of enzyme. Moreover, about the density | concentration of an enzyme, the effect which reduces the valve expansion rate of an explosion-proof valve is recognized by 0.1 wt% with respect to the whole electrolyte solution, The effect tends to become so large that the compounding quantity increases.
Here, when the compounding amount of the enzyme is less than 0.1 wt%, the effect is small ( Comparative Example 1-1), whereas when the compounding amount exceeds 10.0 wt%, the specific resistance of the electrolyte tends to increase ( Comparative Example). 1-6). Therefore, the amount of the enzyme is preferably in the range of 0.1 to 10.0 wt% with respect to the entire electrolyte solution. As for the impregnation temperature, comparing 20 ° C., 40 ° C., and 60 ° C., the expansion coefficient of the explosion-proof valve tended to be relatively small at 40 ° C. and 60 ° C.

Claims (1)

For driving in which at least one enzyme selected from xylanase, lignin peroxidase and cellulase is blended with a solute in a solvent, and the blending amount of the enzyme is in a range of 0.1 to 10.0 wt% with respect to the entire electrolyte. An electrolyte,
A plurality of electrode foils are wound or laminated via electrolytic paper, and a capacitor element impregnated with the driving electrolyte, and
A case for housing the capacitor element;
With
An electrolytic capacitor, wherein the capacitor element is impregnated with the driving electrolyte in a state where at least one of the capacitor element and the driving electrolyte is heated to 20 to 60 ° C.