| 摘要 |
PROBLEM TO BE SOLVED: To restrain generation of gas when abnormally overheated by adding polysaccharide in a nonaqueous electrolyte or a positive electrode active material. SOLUTION: Polysaccharide to be added is a kind of curdlan of polysaccharide produced by microorganism, constitutive sugar is a bonded one of only glucose, and is composed of only a β-1, 3 glucoside bond in a structure, and a chemical structure is expressed by the formula. When abnormal heat is applied from the outside, since the curdlan in a nonaqueous electrolyte is gelatinized by taking a large quantity of nonaqueous electrolytes in a molecule and hinders electrode reaction in a battery, heat from the battery can be reduced. Gelatinization is not caused at 130 deg.C or less. An added quantity is desirably 0.1 to 5 wt.%. The curdlan shows high biodegrdability of almost the same degree as corn starch. When adpoted in a structure for dispersing a binder in an active material tank of a lead-acid battery, the curdlan plays a role of a hole creating agent, enhances porosity of a surface part of a plate, and enhances internal strength of the active material tank. |
