NOVELTY - A non-aqueous electrolyte battery comprises a positive electrode active material layer stack. At least one layer other than the outermost positive electrode layer contains as its main active material a positive electrode active material having the highest resistance increase rate during overcharge among the positive electrode active materials. The layer containing as its main active material the positive electrode active material having the highest resistance increase rate contains a fibrous carbon material as a conductivity enhancing agent.    USE - As e.g. lithium-ion battery and polymer battery.    ADVANTAGE - When at least one layer other than the outermost positive electrode layer contains as its main active material the positive electrode active material having the highest resistance increase rate during overcharge, the current collection performance lowers in the outermost positive electrode layer that has a high reactivity during overcharge. Consequently, the active material of the outermost positive electrode layer is not easily charged to the charge depth that should reach otherwise. Accordingly, the amount of lithium deintercalated from the positive electrode in the overcharge region decreases, reducing the total amount of lithium deposited on the negative electrode. Consequently, the amount of heat produced due to the reaction between the electrolyte solution and the lithium deposited on the negative electrode correspondingly reduces, preventing the deposition of dendrite. The thermal stability of the positive electrode active material (particularly the active material in the outermost positive electrode layer that becomes unstable because of the extraction of lithium from the crystals) is also kept relatively high because the charge depth does not become deep. The reaction between the positive electrode active material and the excessive electrolyte solution existing in the separator can be inhibited. The tolerance of the battery to overcharging can be improved. The use of the fibrous carbon material as the conductivity enhancing agent in the layer containing as the main active material the positive electrode active material having the highest resistance increase rate enables the battery to improve the tolerance of the battery to overcharging more effectively while preventing the battery capacity from degrading.    DETAILED DESCRIPTION - A non-aqueous electrolyte battery comprises a positive electrode including a positive electrode active material (2) layer stack and a positive electrode current collector (1); a negative electrode including a negative electrode active material layer; and a separator interposed between the electrodes. The positive electrode active material layer stack is formed on a surface of the positive electrode current collector. It comprises layers respectively having different positive electrode active materials. Among the layers, at least one layer other than the outermost positive electrode layer contains as its main active material a positive electrode active material having the highest resistance increase rate during overcharge among the positive electrode active materials. The layer containing as its main active material the positive electrode active material having the highest resistance increase rate contains a fibrous carbon material as a conductivity enhancing agent.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic diagram of a heat transfer passage.    Positive electrode current collector (1)    Positive electrode active material (2)    Lower layer (2a)    Upper layer (2b)