JP6035029B2 - Separator material for alkaline battery, separator, alkaline battery, method for producing separator material for alkaline battery - Google Patents

Description

The present invention separator material for alkaline batteries, separators over data, alkaline batteries, and a method for producing an alkaline battery separator material.

  An alkaline battery such as the LR6 type has an alkaline power generation element composed of a positive electrode mixture, a separator, and a negative electrode mixture housed in a bottomed cylindrical metal battery can, and the opening of the battery can has a resin gasket. It is based on a structure that is hermetically sealed using. FIG. 1 shows the structure of the LR6 type alkaline battery 1. The battery 1 is disposed inside a bottomed cylindrical metal battery can (positive electrode can) 2 having a bottom portion, a positive electrode mixture 3 formed into a ring-shaped core, and the positive electrode mixture 3. Consists of a bottomed cylindrical separator 4, a negative electrode gel 5 containing a zinc alloy and filled inside the separator 4, a negative electrode current collector 6 inserted in the negative electrode gel 5, a negative electrode terminal plate 7, a sealing gasket 8, and the like. Is done. In this structure, the positive electrode mixture 3, the separator 4, and the negative electrode gel 5 form the power generation element of the alkaline dry battery 1 in the presence of the electrolytic solution.

  The positive electrode can 2 is a battery case, and when the positive electrode mixture 3 is press-fitted, the positive electrode can 2 is in direct contact with the positive electrode mixture 3 and serves as the positive electrode current collector and the positive electrode terminal 9. The positive electrode mixture 3 is formed, for example, into a ring-shaped core obtained by kneading a conductive material (such as graphite) and a binder (such as polyacrylic acid) using electrolytic manganese dioxide as an active material.

  The negative electrode gel 5 is usually configured to include an electrolytic solution composed of zinc powder, a gelling agent, zinc oxide, and an aqueous potassium hydroxide solution, and a rod-shaped metal negative electrode current collector 6 is inserted into the negative electrode gel 5. ing. The negative electrode current collector 6 is fixed upright by being welded to the inner surface of a plate-shaped metal negative electrode terminal plate 7 at its upper end. The negative electrode terminal plate 7, the negative electrode current collector 6 and the sealing gasket 8 are combined together in advance. Then, the outer peripheral portion of the sealing gasket 8 is placed with the beading portion 10 formed below the opening of the positive electrode can 2 as a seat, and the opening of the positive electrode can 2 is caulked in this state, whereby the negative electrode terminal plate 7 is fitted into the opening via the edge of the gasket 8. Thereby, the positive electrode can 2 is hermetically sealed.

  By the way, in the configuration of the above alkaline dry battery, the separator 4 is formed into a bottomed cylindrical shape by heat-sealing a nonwoven fabric cut into a predetermined shape. The purpose is to insulate the gap (3-5) to prevent an internal short circuit and to absorb ions between the positive and negative electrodes (3-5) by absorbing the electrolyte. Polyolefins (polypropylene, etc.) with excellent alkali resistance are well known as non-woven fabrics used in alkaline battery separators. However, polyolefins have poor liquid absorption and low heat resistance, so that they are bottomed. There is a possibility of damage due to heat when forming into a cylindrical shape. The following Patent Document 1 describes a separator using a nonwoven fabric in which a metal compound is fixed to a base material made of polyolefin. Patent Document 2 describes a separator using a nonwoven fabric made of metal fibers.

JP-A-11-283604 Japanese Patent Laid-Open No. 05-325931

  As a separator material for alkaline batteries, there is a nonwoven fabric using polyolefin as described above. Polyolefin is excellent in alkali resistance, but it cannot be said that it has sufficient performance with respect to heat resistance and liquid absorption. In the invention described in Patent Document 1, liquid absorption is improved by fixing metal compounds (oxides, hydroxides, oxyhydroxides) to polyolefins. It is insufficient. In addition, when the inventor actually manufactured and tested a separator having the same configuration as that of the invention described in Patent Document 1 in the process leading to the present invention, the performance improvement as expected for liquid absorption Was not recognized.

  In the invention described in Patent Document 2, the separator is made of a nonwoven fabric itself of a short fiber mixture made of potassium titanate fibers and alumina fibers for the purpose of improving alkali resistance, heat resistance, wettability with an electrolytic solution, and the like. It is composed. However, with this configuration, the nonwoven fabric is composed only of a metal compound, and there is a problem that it is difficult to process the separator into a bottomed cylindrical shape, resulting in extremely high manufacturing costs. Moreover, when the test regarding a liquid absorptivity was done also about the nonwoven fabric of the said patent document 2, it was not the performance which can be satisfied.

  By the way, as a material used for the separator of an alkaline battery, vinylon and cellulose are well known. When the characteristics of vinylon and cellulose are evaluated relative to each other, vinylon is excellent in heat resistance and cellulose is excellent in liquid absorption. That is, vinylon and cellulose have a problem that both heat resistance and liquid absorption properties are contradictory, and in a separator using a nonwoven fabric in which both materials are mixed, heat resistance and absorption are dependent on the mixing ratio. There was a problem that one of the liquid properties deteriorated.

  Then, this invention aims at providing the separator material excellent in both heat resistance and liquid absorption property, the separator using the material, and the alkaline dry battery using the said separator.

The present invention for achieving the above object is a material used for a separator for an alkaline dry battery, and a non-woven fabric containing vinylon and cellulose as main components, and titanium of any one of titanium hydroxide and titanium oxyhydroxide. The separator material for an alkaline battery is characterized in that a compound is adhered .

Ranges separator also of the present invention using the separator material the alkaline dry battery, the separator is directed to that the material which is cut into a predetermined shape is formed in which heat-sealed cylindrical shape with a bottom. Furthermore, the present invention extends to an alkaline dry battery in which the separator formed in the bottomed cylindrical shape is used.
In addition, the method for producing the separator material for alkaline dry batteries is also within the scope of the present invention, and the production method comprises adding a titanium compound of titanium hydroxide or titanium oxyhydroxide to a nonwoven fabric mainly containing vinylon and cellulose. And a step of irradiating the non-woven fabric to which the titanium compound is added with an ultraviolet ray.

  According to the separator material for an alkaline battery of the present invention, heat resistance is improved, and problems such as opening of holes when forming into a bottomed cylindrical separator can be prevented by heat sealing. That is, manufacture of a separator becomes easy. Further, the liquid absorbency is improved, and the performance of the alkaline battery can be improved.

It is a structural diagram of an alkaline battery.

=== Structure of alkaline battery and separator material ===
The separator using the separator material according to the embodiment of the present invention has the same structure as that incorporated in the conventional alkaline battery 1 shown in FIG. That is, the nonwoven fabric is heat-sealed so as to have a bottomed cylindrical shape. However, the separator material itself constituting the separator has a composition different from that of the conventional material, and due to the difference, the separator material is superior in heat resistance and liquid absorption. In the following, the separator material according to the present invention will be described with reference to more specific examples. Further, in the description, when referring to each part of the alkaline battery, the reference numerals shown in FIG. 1 are used as necessary.

=== First Embodiment ===
The separator material according to the first embodiment of the present invention is a non-woven fabric made of vinylon and cellulose as a base material, and a metal compound is adhered to the base material. Here, a titanium compound is employed as the metal compound. Specifically, a vinylon fiber in a state where powder or granular TiO ₂ , Ti (OH) ₄ , TiO (OH) ₂ , and Na ₂ TiO ₃ are dissolved or suspended in water as a medium. And a nonwoven fabric mainly composed of cellulose fibers are made by a wet method, and water is evaporated by a drying process to adhere each metal compound to the nonwoven fabric.

Of the types of titanium compounds that adhere to the nonwoven fabric, TiO ₂ , Ti (OH) ₄ , and TiO (OH) ₂ can be used to control any of these titanium compounds by controlling the temperature and time in the drying process. It is attached to the nonwoven fabric. For example, when the temperature of the drying process is kept constant, Ti (OH) ₄ , TiO (OH) ₂ , and TiO ₂ adhere in this order as the drying time elapses.

  Samples were made of various separator materials with different vinylon and cellulose mixing ratios and different types of attached metal compounds, nonwoven fabrics made of polyolefin as conventional separator materials, and nonwoven fabrics made of potassium titanate fibers and alumina fibers. Each sample was evaluated for heat resistance and liquid absorption.

<Performance evaluation test>
Each sample is a test piece cut to be a square having a basis weight of 40 g / m ² , a thickness of 0.12 mm, and a length and width of 56 mm. And for heat resistance, the test piece is double-wound so as to form a hollow cylinder with an outer diameter of 9 mm, one end surface of the hollow cylinder is pressed against a heater at a constant temperature, and the edge of the test piece is heat-sealed. The sample is produced under the same conditions, and a plurality of separators 4 are produced by changing the temperature of the heater for the sample produced under the same conditions. The maximum temperature when the hole was not opened (heat-resistant temperature) was evaluated.

On the other hand, the liquid absorptivity was evaluated by immersing the test piece in a 40 wt% KOH aqueous solution, which is the electrolyte of the alkaline dry battery 1, and determining the mass ratio (liquid retention) before and after immersion. In addition, if the mass before immersion is W1, the mass after immersion is W2, and the liquid retention is R,
R (%) = (W2−W1) / W1 × 100
It becomes.

<Sample conditions>
Table 1 below shows the production conditions for each sample and the test results for each sample.

  As shown in Table 1, the vinylon and cellulose nonwoven fabrics to which any of the above titanium compounds (hereinafter referred to as titanium compounds) are not attached are Samples A1, A6, and A11. The ratio is different. The heat resistance and the liquid retention ratio were inconsistent depending on the ratio of the vinylon and cellulose, and the heat resistance and the liquid retention ratio were 250 ° C. and 350%, respectively, in the sample A1 having the same vinylon / cellulose ratio. On the other hand, in sample A6 where vinylon is 70% and cellulose is 30%, the heat resistance and the liquid retention are 300 ° C. and 300%, respectively. Declined. Conversely, in sample A11 with 30% vinylon and 70% cellulose, the heat resistance and liquid retention were 200 ° C. and 400%, respectively.

Samples A16 to A18 are conventional separator materials, sample A16 is a nonwoven fabric made of metal compound fibers, and sample A17 is a nonwoven fabric made of polypropylene, which is a typical polyolefin. Sample A18 is a separator material was deposited Ti0 ₂ in polypropylene. Samples A2 to A5, A7 to A10, and A12 to A15 are separator materials according to the first embodiment of the present invention, and a titanium compound is adhered to a nonwoven fabric made of vinylon and cellulose. And in sample A2-A5, A7-A10, A12-A15, the mixing ratio of the vinylon and cellulose contained in the nonwoven fabric used as a base material, and the kind of the attached titanium compound differ, respectively.

<Test results>
From the results shown in Table 1, it can be seen that samples A16 to A18 made of the conventional separator material are inferior in the liquid retention rate to the basic samples A1, A6, A11. Sample A16 made of a metal compound non-woven fabric cannot be heat-sealed as a matter of course, so heat resistance has not been confirmed. Of course, since the sample A16 is composed of only a metal compound, the heat-resistant temperature is expected to be extremely high. However, since it is difficult to form a bottomed cylindrical separator, it is practically an alkaline dry battery. Cannot be used as a separator material. Moreover, in sample A17 which consists only of a nonwoven fabric of polypropylene, heat resistance with a liquid retention rate is very inferior to basic sample A1, A6, A11. Sample A18 in which TiO ₂ was adhered to a polypropylene nonwoven fabric also showed some improvement in performance, but both heat resistance and liquid retention were inferior to basic samples A1, A6, and A11.

  On the other hand, in the samples A2 to A5, A7 to A10, and A12 to A15 according to the first example, if the ratio of vinylon and cellulose is the same, both the heat resistant temperature and the liquid retention rate are obtained by adding a titanium compound. It was confirmed that it improved. Moreover, even when the ratio of vinylon and cellulose is changed, by adding a titanium compound, the performance of either the heat resistant temperature or the liquid retention rate is improved over the basic samples A1, A6, A11, while the other Maintained equivalent performance. For example, when the sample A1 and the samples A7 to A10 are compared, the liquid retention rate is the same, but the heat resistant temperature is improved. When the sample A1 and the samples A12 to A15 are compared, the heat-resistant temperature is the same, but the liquid retention rate is improved. This is because, in the samples A2 to A5, A7 to A10, and A12 to A15 according to the first embodiment, even if the ratio of vinylon and cellulose is changed, deterioration of one characteristic of heat resistance and liquid absorption is suppressed, and the other It can be considered that the characteristics of

  Specifically, in the sample according to the first example, the high heat resistance in the metal compound and the permeability (wettability) of the electrolytic solution complement the deterioration of the heat resistance when the ratio of vinylon is low, and cellulose On the contrary, when the ratio of cellulose is low, it can be considered that deterioration of the liquid absorbability is complemented and the heat resistance of vinylon is enhanced.

== Second Embodiment ===
In the first example, the heat resistance and the liquid retention rate were improved by adding a titanium compound to a nonwoven fabric made of vinylon and cellulose. Next, an attempt was made to further improve the wettability of the electrolytic solution by mainly modifying the surface properties of the titanium compound by utilizing the characteristics of titanium as a photocatalyst. Here, the separator 4 is produced using the separator material produced under the same conditions as the samples A1 to A5 in Table 1 and the separator material according to the second embodiment of the present invention in which the samples A2 to A5 are irradiated with ultraviolet rays. At the same time, the separator 4 was incorporated into the battery can 2 to produce various alkaline batteries 1. And using the produced alkaline dry battery 1, the liquid absorption property of the electrolyte solution in the separator 4 and the discharge performance of the alkaline dry battery 1 were evaluated. Further, as a comparative example for the separator material according to the second example, a separator material produced under the same conditions as those of the samples A16 to A18 as the separator material of the first example, and a separator material irradiated with ultraviolet rays on the sample 18 were used. Prepared, separators using these separator materials were incorporated into alkaline batteries, and their liquid absorbency and discharge performance were also evaluated.

<About the sample>
As in the first example, the separator 4 using the separator material according to the second example and the comparative example is a square having a basis weight of 40 g / m ² , a thickness of 0.12 mm, and a length and width of 56 mm. The test piece cut into two is wound in a hollow cylinder shape having an outer diameter of 9 mm, and one end face of the hollow cylinder is pressed against a heater at a constant temperature to thermally bond the edge, thereby a height of 48 mm. It is a bottomed cylinder. Then, using the separator 4, an LR6 type alkaline dry battery 1 having the structure shown in FIG. 1 was produced, and the liquid absorbency and the discharge performance were evaluated using the alkaline dry battery 1 as a sample.

<Performance evaluation test>
The liquid absorption is the weight when the positive electrode mixture 3 and the separator 4 are impregnated with an electrolytic solution composed of a 37 wt% potassium hydroxide aqueous solution in the manufacturing process of the alkaline dry battery 1 and the excess electrolytic solution is sucked out after 20 minutes. Rated by increase. In the evaluation, the relative value when the weight increase in the sample prepared using the separator material of the basic sample A1 in Table 1 is 100 was adopted.

  In addition, regarding the discharge performance, for the assembled alkaline dry battery 1 as a sample, after discharging 1500 mW of power in 2 seconds and then discharging 650 mW of power in 28 seconds, this operation is performed every hour. Ten cycles were performed, and the time until the end voltage reached 1.05 V was evaluated. The discharge characteristics were also evaluated relative to the test result of the alkaline dry battery 1 using the separator material of sample A1 in Table 1 as 100.

<Test results>
Table 2 below shows the production conditions for each sample and the test results for each sample.

  In the said Table 2, the preparation conditions of the material used for the separator 4, and the test result of liquid absorptivity and discharge performance are shown. Samples using separator materials with the same production conditions are given the same numbers as in Table 1. That is, the samples B1 to B5 and B16 to B18 in Table 2 use the separator materials (A1 to A5 and A16 to A18) indicated by the same numbers in Table 1, and the evaluation results of each test are basic. The value is relative to the sample B1. And the separator material in sample B19-B22 has irradiated the ultraviolet-ray to the nonwoven fabric which consists of vinylon and the cellulose which adhered the titanium compound. Sample B23 is a separator material obtained by irradiating polypropylene with a titanium compound attached thereto with ultraviolet rays.

  From the results shown in Table 2, with respect to sample B1 using a nonwoven fabric made of vinylon and cellulose as a separator material, in samples B2 to B4 in which a titanium compound was adhered to the nonwoven fabric of this sample B1, the liquid absorbency was improved. The discharge performance was improved with the improvement of liquid absorption. And the separator material which irradiated the ultraviolet-ray to the separator material used by sample B2-B4 is a 2nd Example of this invention, In sample B19-B22 using the separator material which concerns on the 2nd Example, Even in the same structure, both liquid absorbency and discharge performance were further improved as compared with Samples B2 to B4 using separator materials that were not irradiated with ultraviolet rays.

  On the other hand, sample B16 using a non-woven fabric made of potassium titanate and alumina fibers as a separator material cannot be formed into a bottomed cylindrical separator 4 as in the results shown in Table 1, and an LR6 type alkaline battery 1 could not be incorporated, and liquid absorption and discharge performance could not be evaluated. Even if it can be formed into a bottomed cylindrical shape, it is expected from the results shown in Table 1 above that the possibility of improving the liquid absorbency and the discharge performance with respect to the sample B1 is extremely low. Of course, even if the separator material of Sample B16 is irradiated with ultraviolet rays, no significant performance improvement can be expected.

Further, sample B17 using a separator material made of a polypropylene nonwoven fabric which is polyolefin, and sample B18 using a separator material in which TiO ₂ is adhered to the polypropylene nonwoven fabric are also compared with samples B1 to B5 and B19 to B22. As a result, both the liquid absorbability and the discharge performance were greatly inferior. The same applies to Sample B23 using the separator material obtained by irradiating the separator material of Sample 18 with ultraviolet rays. Although this sample 23 was the same as the sample B2 using the separator material of the second example except for the configuration of the nonwoven fabric, the effect of improving the characteristics by irradiating ultraviolet rays was slight. That is, the separator material in which a titanium compound is added to a non-woven fabric made of vinylon and cellulose has a remarkable effect of improving the characteristics due to ultraviolet irradiation, and becomes a base material, rather than a separator material in which a titanium compound is added to a non-woven fabric made of polyolefin. The material was confirmed to be significant.

=== Other Embodiments ===
In the first and second embodiments, the titanium compound is added as a metal compound to the nonwoven fabric made of vinylon and cellulose. However, in the case of the first embodiment only, metals other than titanium may be used. Good. It is non-conductive and does not cause gas or internal short circuit even when it comes into contact with the positive electrode or negative electrode. Oxides such as magnesium, aluminum, silicon, calcium, zinc, zirconium, hydroxide, oxyhydroxide, and Oxo acid salts are possible. In the metal compound containing these metals, improvement in heat resistance and liquid absorption is expected as in the first embodiment.

DESCRIPTION OF SYMBOLS 1 Alkaline battery, 2 battery can, 3 positive electrode mixture, 4 separator, 5 negative electrode gel 6 negative electrode current collector, 7 negative electrode terminal board, 8 sealing gasket, 9 positive electrode terminal

Claims (4)

A material used for alkaline battery separators,
A non-woven fabric containing vinylon and cellulose as main components is attached with a titanium compound of either titanium hydroxide or titanium oxyhydroxide .
A separator material for alkaline dry batteries. A separator with a separator material for alkaline dry battery of claim 1, a separator, characterized in that the material which has been cut into a predetermined shape is formed in which heat-sealed cylindrical shape with a bottom. An alkaline battery using the separator according to claim 2 . It is a manufacturing method of the separator material for alkaline dry batteries of Claim 1,
Adding a titanium compound of titanium hydroxide or titanium oxyhydroxide to a non-woven fabric containing vinylon and cellulose as main components;
Irradiating the nonwoven fabric to which the titanium compound is added with ultraviolet rays;
The manufacturing method of the separator material for alkaline dry batteries characterized by including.

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