Non-aqueous liquid electrolyte secondary cell

A non-aqueous liquid electrolyte secondary cell comprising:

• a non-aqueous liquid electrolyte made by dissolving LiPF.sub.6 in a mixed solvent of propylene carbonate, dimethyl carbonate and diethyl carbonate;
• a positive electrode including a positive collector and a positive active material layer formed on the positive collector, the positive active material layer comprising a positive active material represented by LixCoO.sub.2, where x is between 0.05 and 1.10 (0.05.ltoreq.x.ltoreq.1.10), and an additive selected from the group consisting of lithium phosphate and cobalt (II) phosphate;
• a negative electrode including a negative collector and a negative active material layer formed on the negative collector, the negative active material layer comprising a negative active material consisting of amorphous carbon having lithium ion occluding and releasing properties;
• a current breaking device for interrupting electrical connection between said electrodes and cell terminals when an internal pressure of said cell is excessively increased;
• and
• a relief valve for releasing a pressure in said cell when an internal pressure of said cell reaches a predetermined level or above;
• said phosphate compound being contained in an amount equal of 0.2 to 15% by weight based on said positive active material;
• said phosphate compound having an average particle diameter of 30 .mu.m or less;
• said positive electrode and negative electrode being spirally wound up while interposing an electrolyte layer containing said electrolyte therebetween.