KR0152262B1 - Battery separator - Google Patents

Abstract

The present invention is a stand-up separator and is a stand-up separator to improve the absorption rate by fixing a surfactant such as the following formula with an ultrasonic processor.

Description

Base Separator

The present invention relates to a bed separator. More specifically, the present invention relates to a membrane separator having a high absorption rate, high absorption rate, and low electrical resistance by fixing a surfactant to a porous sheet.

Manufacturing methods for the base separator are disclosed in several patents (US Pat. Nos. 3,351,495, 4,024,323, 4,237,083, 4,335,193, UK Patent 2,027,637, 2,083,823). The technique shown in the patent is a method for producing a sheet having a porosity by extracting the plasticizer after molding by mixing a polyolefin resin, a silica and a plasticizer. However, the patent separator of the patent has a drawback that usually shows a slow speed of 2 hours or more in the wettability analysis, which measures the time of absorption by dropwise addition of 0.5 ml of sulfuric acid aqueous solution.

SUMMARY OF THE INVENTION An object of the present invention is to provide a secondary separator with improved absorption rate by adhering a surfactant of the following formula to the surface of a porous sheet composed of polyolefin resin, silica and a plasticizer and the surface of micropores by sonication.

Polyolefin resins suitable for the present invention may be polyethylene, polypropylene, and silica may be a product having a high specific surface area and high plasticizer dioctylphthalate (DOP) oil absorption. Silica is hydrophilic and absorbs water well. Polyolefin resin is hydrophobic and serves to resist water absorption, thereby achieving balance.

The higher the rate of absorption, the better the start-up even in cold weather. The absorption rate can be increased simply by the addition of hydrophilic additives, but if used incorrectly, it can increase the electrical resistance by generating bubbles on the surface of the separator.

Nonylphenoxypolyethyleneoxyethanol to be used as the surfactant of the present invention may have a hydrophilic-lipophilic balance (HLB) of 5 to 12, preferably 7 to 10.

1 to 5% by weight of the surfactant is added to an alcoholic solution having an alcohol content of 20 to 60% by weight to prepare a solution, followed by ultrasonication while passing through the porous sheet in the solution, and the surfactant is coated on the surface of the micropores. To be. The amount to be coated is 0.1 to 1% by weight of the weight ratio of the film, and to control the coating amount, the sonication time should be appropriately adjusted.

The absorption rate of the base separator according to the present invention was greatly improved. The absorption rate before the surface treatment of nonylphenoxypolyethyleneoxyethanol was 120 to 150 minutes, whereas the absorption rate was shortened to about 60 to 80 minutes after the surface treatment. In addition, when the water absorption was compared, it was improved to 100 to 110 wt% before treatment and 120 to 130 wt% after treatment.

Electrical resistance was the beam is lowered effect, decreased from 130 to 140mΩ ^-1 cm ² at 80 to 90mΩ ^-1 cm ^2. This can be confirmed by Table 1 according to Examples and Comparative Examples to be described later.

The following Examples and Comparative Examples will be described.

[Production example]

A plasticizer (dioctylphthalate, mineral oil, polyethylene glycol, etc.) is absorbed into silica (NIPSIL E-220A; specific surface area 130 m ² / g, average particle size 1 μm), and a polyethylene resin (high density polyethylene, MI = 0.1 or less, specific gravity 0.956), and then extruder is taken out into a sheet shape. This is extracted in a solvent in which the plasticizer dissolves well, and then the solvent is blown off in a drier to prepare a sheet-shaped specimen.

Example 1

After preparing in the form of a sheet with silica (NIPSIL E-220A), polyethylene resin HDPE (HIVOREX 7000F), and plasticizer (DOP), extracting the plasticizer from trichloroethylene and drying to prepare a specimen as in the preparation example. It is dried in an aqueous solution of 50 wt% of ethanol to dissolve nonylphenoxypolyethyleneoxyethanol (HLB = 7) in 5 wt%. After soaking the prepared sheet specimen in this solution, it is sonicated for 5 minutes and then taken out and dried (100 ° C. or lower) to prepare a stand-up separator. The physical properties of these separators are shown in Table 1.

Example 2

Prepared similarly to Example 1, except that the mineral oil as a plasticizer (hereinafter referred to as MO), the sonication time in a nonylphenoxypolyethyleneoxyethanol (hereinafter referred to as NPOE) aqueous solution of 5 minutes to prepare a separator, the physical properties 1 is shown.

Example 3

Prepared in the same manner as in Example 1, polyethylene glycol (PEG) as a plasticizer to prepare a separator with a sonication time of 5 minutes in an aqueous solution of NPOE to prepare a separator and the physical properties are shown in Table 1.

Example 4

Prepared similarly to Example 1, but prepared as a plasticizer with a sonication time of 10 minutes M.O.

Example 5

Prepared similarly to Example 4, but prepared a separator with a sonication time of 20 minutes and the physical properties are shown in Table 1.

Example 6

Prepared similarly to Example 4, but prepared as a separator with a sonication time of 30 minutes and shown in Table 1 physical properties.

Comparative Example 1

Prepared in a similar manner to Example 1 but not sonicated in an aqueous solution of NPOE aqueous solution treated for 5 minutes to prepare a separator and the physical properties are shown in Table 1.

Comparative Example 2

Prepared in a similar manner to Example 2 but not sonicated with an aqueous solution of NPOE aqueous solution for 5 minutes to prepare a separator and the physical properties are shown in Table 1.

Comparative Example 3

Prepared in a similar manner to Example 3 but not sonicated in an aqueous solution of NPOE aqueous solution for 5 minutes to prepare a separator and the physical properties are shown in Table 1.

[How to measure]

Claims (1)

In the support membrane consisting of high density polyethylene, silica and a plasticizer, the surface is coated with a coating solution made by dissolving 1 to 5 wt% of nonylphenoxypolyethyleneoxyethanol having a HLB of 7 to 8 in an aqueous solution of 20 to 60 wt% of the following formula: Stand separator, characterized in that.