ORGANIC EXPANDER FOR LEAD STORAGE BATTERIES, AND METHOD FOR PRODUCING SAME

Abstract

An organic expander for lead storage batteries and a method for producing the same wherein: an organic expander for lead storage batteries containing lignosulfonate, in which a content of reducing sugars per solid content is 5% by mass or less of the total, and a content of a substance with a molecular weight of 5,000 or less per solid content is 30% by mass or less of the total; and a method for producing the organic expander for lead storage batteries, the method including a step of subjecting a sulfite cooking black liquor to ultrafiltration treatment using an ultrafiltration membrane to recover a concentrated liquor of the sulfite cooking black liquor obtained.

Claims

1. A method for producing an organic expander for lead storage batteries containing lignosulfonate, the method comprising a step of subjecting a sulfite cooking black liquor to ultrafiltration treatment using an ultrafiltration membrane to recover a concentrated liquor of the sulfite cooking black liquor obtained.

2. An organic expander for lead storage batteries containing lignosulfonate, wherein a content of reducing sugars per solid content is 5% by mass or less of the total, and a content of a substance with a molecular weight of 5,000 or less per solid content is 30% by mass or less of the total.

Description

EXAMPLES

[0088] Hereinafter, the present invention will be described in detail with reference to Examples. The following examples are intended to suitably illustrate the present invention, and do not limit the present invention.

<Ultrafiltration Treatment of Black Liquor>

[0089] Sun X M100 (manufactured by NIPPON PAPER INDUSTRIES CO., LTD., concentration: 12%, main ingredient: lignosulfonate) was subjected to ultrafiltration treatment (molecular weight cut off: 20,000) to be 4 times concentrated and make it 1.0 time constant volume, and the obtained concentrated liquor was pulverized in a vacuum dryer (105° C., 24 h) to obtain lignosulfonate powder (Lignin 1). Further, Sun X M100 was subjected to ultrafiltration treatment (molecular weight cut off: 12,000) to be 4 times concentrated and make it 1.0 time constant volume, and the obtained concentrated liquor was pulverized in a vacuum dryer (105° C., 24 h) to obtain lignosulfonate powder (Lignin 2). Furthermore, Sun X M100 was pulverized without performing ultrafiltration treatment to obtain lignosulfonate powder (Lignin 3).

[0090] Physical property values of Lignins 1 to 3 are shown in Table 1 below. Note that % in Table 1 represents % with respect to the solid content.

TABLE-US-00001 TABLE 1 Weight Content of average molecular molecular weight of Reducing weight 5,000 Sample sugars Mw or less name (%) (RI) (%) Lignin 1 2.6 31000 9.0 Lignin 2 2.8 21000 22.0 Lignin 3 15.8 9000 65.0

<Preparation of Lead Storage Battery>

[0091] The lead storage battery positive electrode active material pastes of the present examples and comparative example were produced as follows in accordance with JP H09-237632 A. First, a lead powder containing 70 to 80% by weight of lead monoxide, 13% by mass of dilute sulfuric acid (specific gravity 1.26: 20° C.) based on the lead powder, and 12% by mass of water based on the lead powder were kneaded to prepare a positive electrode active material paste. About 25 g of the paste-like positive electrode active material was filled in a current collector made of a lead alloy grid, and then left (cured) in an undried state at 80° C. for 24 hours in a nitrogen atmosphere to obtain an unformed positive electrode plate.

[0092] Next, a lead powder containing 70 to 80% by weight of lead monoxide, 13% by mass of dilute sulfuric acid (specific gravity 1.26: 20° C.) based on the lead powder, 12% by mass of water based on the lead powder, 1.2% by mass of barium sulfate, and 0.3% by mass of an organic expander were added and kneaded to prepare a negative electrode active material paste. About 25 g of the negative electrode active material paste was filled in a current collector made of a lead alloy grid, and then left (cured) in an undried state at 80° C. for 24 hours in a nitrogen atmosphere to obtain an unformed negative electrode plate.

[0093] The negative electrode plate and the positive electrode plate obtained by the above production method were combined to prepare a lead storage battery with a rated capacity of 28 Ah-2 V.

(High-Rate Discharge Characteristic Test)

[0094] A high-rate discharge characteristic test at 150 A was performed in accordance with JIS D5301. Discharge duration time was evaluated. The longer the discharge duration time is, the better the evaluation is.

(Charge Acceptance Test)

[0095] A charge acceptance test was performed in accordance with JIS D5301. Charging current in 10 minutes after the start of charging was evaluated. The higher the current value is, the better the evaluation is.

(5-Hour Rate Capacity Test)

[0096] A 5-hour rate capacity test was performed in accordance with JIS D5301. Discharge duration time was evaluated. The longer the discharge duration time is, the better the evaluation is.

[0097] The test result is shown in Table 2.

TABLE-US-00002 TABLE 2 High-rate 5-Hour Organic discharge Charge rate expander characteristic acceptance capacity (lignin) test test test Example 1 Lignin 1 3.5 min 12.6 A 5.4 h Example 2 Lignin 2 3.4 min 11.8 A 5.3 h Comparative Lignin 3 3.4 min  9.4 A 4.8 h Example

[0098] As shown in Table 2, the organic expanders for lead storage batteries of the present invention in Examples 1 and 2 had almost the same high-rate discharge characteristics and excellent charge acceptance as compared with the organic expander for lead storage batteries of Comparative Example. In addition, the organic expanders for lead storage batteries of the present invention in Examples 1 and 2 were also excellent in 5-hour rate capacity as compared with the organic expander for lead storage batteries of Comparative Example.