Abstract: Based on a voltage of a secondary battery detected by a voltage measurement unit, a residual capacity is acquired from a correlation between the voltage and the residual capacity of the secondary battery stored in a memory, and a state of charge (SOC) which is a ratio of the residual capacity to a reference capacity is obtained. The reference capacity is set to a prescribed amount less than a residual capacity at full charge. Further, an information processing unit determines an abnormality of a module based on a comparison between the SOC and an SOC obtained by another method.

Abstract: Based on a voltage of a secondary battery detected by a voltage measurement unit, a residual capacity is acquired from a correlation between the voltage and the residual capacity of the secondary battery stored in a memory, and a state of charge (SOC) which is a ratio of the residual capacity to a reference capacity is obtained. The reference capacity is set to a prescribed amount less than a residual capacity at full charge. Further, an information processing unit determines an abnormality of a module based on a comparison between the SOC and an SOC obtained by another method.

Abstract: An object is to provide a positive active material for nonaqueous electrolyte secondary battery, which is capable of providing a battery with excellent cycle performance. Provided are a positive active material for nonaqueous electrolyte secondary battery, which includes an Fe-containing lithium vanadium phosphate compound having a NASICON-type structure, wherein in the Fe-containing lithium vanadium phosphate compound, the percentage of iron atoms relative to the sum of vanadium and iron atoms is 2% or more and 20% or less; and the like.

Abstract: The present invention provides a Li3V2(PO4)3-based positive active material for a lithium secondary battery, which has high discharge capacity and excellent storage performance, particularly high-temperature storage performance; and a lithium secondary battery made using the positive active material. The positive active material for a lithium secondary battery has general formula Li3V2(PO4)3?x(BO3)x (0<x?2?2). It is preferable that x be 2?7?x?2?3. Also provided are a positive electrode for a lithium secondary battery containing the positive active material; and a lithium secondary battery including the positive electrode.

Abstract: The invention provides a polyanion-based positive active material which can improve storage stability (especially, high temperature storage stability), charge and discharge cycle performance and the like of a lithium secondary battery, and a lithium secondary battery using the same. The positive active material for a lithium ion secondary battery contains lithium iron cobalt phosphate represented by the general formula: LiyFe(1-x)CoxPO4(0<x?0.019, 0?y?1.2). By using the positive active material for a lithium secondary battery, high temperature storage stability and charge and discharge cycle performance can be improved in comparison with a case where LiyFePO4 containing no Co is used. By using the positive active material, a lithium ion secondary battery can be suitable for applications in fields of electric automobiles and industrial batteries in which long lives, high capacities, and high output powers are required.

Abstract: An object is to provide a positive active material for nonaqueous electrolyte secondary battery, which is capable of providing a battery with excellent cycle performance. Provided are a positive active material for nonaqueous electrolyte secondary battery, which includes an Fe-containing lithium vanadium phosphate compound having a NASICON-type structure, wherein in the Fe-containing lithium vanadium phosphate compound, the percentage of iron atoms relative to the sum of vanadium and iron atoms is 2% or more and 20% or less; and the like.

Abstract: The present invention provides a Li3V2(PO4)3-based positive active material for a lithium secondary battery, which has high discharge capacity and excellent storage performance, particularly high-temperature storage performance; and a lithium secondary battery made using the positive active material. The positive active material for a lithium secondary battery has general formula Li3V2(PO4)3-x(BO3)x (0<x?2?2). It is preferable that x be 2?7?x?2?3. Also provided are a positive electrode for a lithium secondary battery containing the positive active material; and a lithium secondary battery including the positive electrode.

Abstract: The invention provides a polyanion-based positive active material which can improve storage stability (especially, high temperature storage stability), charge and discharge cycle performance and the like of a lithium secondary battery, and a lithium secondary battery using the same. The positive active material for a lithium ion secondary battery contains lithium iron cobalt phosphate represented by the general formula: LiyFe(1-x)CoxPO4 (0<x?0.019, 0?y?1.2). By using the positive active material for a lithium secondary battery, high temperature storage stability and charge and discharge cycle performance can be improved in comparison with a case where LiyFePO4 containing no Co is used. By using the positive active material, a lithium ion secondary battery can be suitable for applications in fields of electric automobiles and industrial batteries in which long lives, high capacities, and high output powers are required.