| abstract |
A non-aqueous secondary battery which comprises a negative electrode comprising a material which can be doped and dedoped with lithium as a negative electrode active material, a positive electrode comprising a lithium-containing transition metal oxide as a positive electrode active material, and a non-aqueous electrolyte as an electrolyte. The separator includes in the inside thereof a net-work-like support and is comprised of a porous film of an organic polymer which swells with the electrolyte to hold the electrolyte, the net-work-like support has an average film thickness of 10-30 mum, a basis weight of 6-20 g/m<2>, a Gurley value (JIS P8117) of 10 sec./100 cc or less, a MacMullin number of 10 or smaller at 25 DEG C and a MacMullin number x average film thickness value of 200 mum or less, the separator has an average film thickness of 10-35 mum, a basis weight of 10-25 g/m<2> and a Gurley value (JIS P8117) of 60 sec./100 cc or less or over 60 sec./100 cc up to 500 sec./100 cc, and where Qp (mAh/mg) is a value obtained by calculating a total amount of lithium contained in the positive electrode active material in terms of an electric charge, Qpr (mAh/mg) is a value obtained by calculating an amount of lithium utilized for a charging and discharging reaction of lithium contained in the positive electrode active material in terms of an electric charge, Qn (mAh/mg) is a value obtained by calculating an amount of lithium capable of being doped into the negative electrode active material, qm (mAh/cm<2>) is a characteristic value for an overcharging-preventing function of the separator, Wp (mg/cm<2>) is a weight of the positive electrode active material and Wn (mg/cm<2>) is a weight of the negative electrode active material, a relationship of QprWp < qm+QnWn < 1.3 QpWp is satisfied. |