Nonaqueous electrolyte secondary battery

A nonaqueous electrolyte secondary battery comprising:

• a positive electrode;
• a negative electrode;
• and
• a separator that is interposed between the positive electrode and the negative electrode, wherein
• the positive electrode comprises a positive electrode current collector, a first positive electrode mixture layer that is provided on the positive electrode current collector, and a second positive electrode mixture layer that is provided on the first positive electrode mixture layer to face the separator,
• the first positive electrode mixture layer comprises a first positive electrode active material and a first conductive material,
• the second positive electrode mixture layer comprises a second positive electrode active material and a second conductive material,
• the first positive electrode active material comprises a lithium composite oxide having a layered crystal structure,
• the second positive electrode active material consists of LiFePO4 as a lithium composite phosphate having an olivine-type crystal structure in an amount of 20 mass % to 75 mass % of an entire weight of the second positive electrode active material and a lithium composite oxide having a layered crystal structure as the rest of the weight of the second positive electrode active material,
• the second conductive material comprises a conductive material having a crushing strength that is more than 1 time and 3 times or less higher than the lithium composite phosphate having the olivine-type crystal structure, and
• the crushing strength is measured according to JIS Z 8841-1993.

A nonaqueous electrolyte secondary battery comprising:

• a positive electrode;
• a negative electrode;
• and
• a separator that is interposed between the positive electrode and the negative electrode, wherein
• the positive electrode comprises a positive electrode current collector, a first positive electrode mixture layer that is provided on the positive electrode current collector, and a second positive electrode mixture layer that is provided on the first positive electrode mixture layer to face the separator,
• the first positive electrode mixture layer comprises a first positive electrode active material and a first conductive material,
• the second positive electrode mixture layer comprises a second positive electrode active material and a second conductive material,
• the first positive electrode active material comprises a lithium composite oxide having a layered crystal structure,
• the second positive electrode active material consists of LiFePO4 as a lithium composite phosphate having an olivine-type crystal structure in an amount of 20 mass % to 75 mass % of an entire weight of the second positive electrode active material and a lithium composite oxide having a layered crystal structure as the rest of the weight of the second positive electrode active material,
• the second conductive material comprises a conductive material having a crushing strength that is more than 1 time and 3 times or less higher than the lithium composite phosphate having the olivine-type crystal structure,
• the crushing strength is measured according to JIS Z 8841-1993, and
• a content of the LiFePO4 is 5 mass % to 20 mass % with respect to a sum of a content of the first positive electrode active material and a content of the second positive electrode active material.