Prime Planet Energy & Solutions, Inc.

Sanyo Electric Co., Ltd.

Hirofusa Tanaka

Toshiyuki Nohma

Yasuhiro Yamauchi

Yasuyuki Kusumoto

Toyoki Fujihara

Shigeki Matsuta

Seiji Omura

Masahide Miyake

Tetsuya Okado

Masahiro Iyori

Takeshi Yoshida

Masashi Muraoka

Kazuki Takeno

Keisuke Minami

Yuji Ogishima

Naoki Terada

Mio Nosaka

In a cross section parallel to a thickness direction of a negative electrode active material layer, an average tortuosity ratio is 1.5 to 2.5. The average tortuosity ratio is calculated by the following formula: 'R=B/A'. In the formula, “R” represents the average tortuosity ratio. “B” represents an average value of lengths of shortest routes each extending from a contact point between a negative electrode substrate and a negative electrode active material particle to a surface of the negative electrode active material layer along contour lines of a plurality of negative electrode active material particles. “A” represents an average value of a thicknesses of the negative electrode active material layer.

Nonaqueous electrolyte secondary battery including negative electrode active material layer with reasonable large tortuosity ratio

A nonaqueous electrolyte secondary battery includes an electrode assembly and an electrolyte solution. The electrode assembly is impregnated with at least part of the electrolyte solution. The electrode assembly includes a positive electrode, a negative electrode, and a separator. The separator separates the positive electrode and the negative electrode from each other. The negative electrode includes a negative electrode active material. The negative electrode active material includes graphite. The following relation of a formula (1) is satisfied: '1.60&#x2264;NPR/AAR&#x2264;2.55'. 'NPR' represents a ratio of a negative electrode charging capacity to a positive electrode charging capacity. &#x201c;AAR&#x201d; represents a ratio of an effective discharging capacity of the negative electrode to a total of a capacity corresponding to an amount of inactive lithium adhered to the negative electrode and the effective discharging capacity of the negative electrode.

Nonaqueous electrolyte secondary battery

A nonaqueous secondary battery includes a current cutoff mechanism that cuts off a current in a short period of time in response to a rise in pressure inside a battery outer body in at least one of a conductive path through which a current is taken out from a positive electrode plate to outside of the battery and a conductive path through which a current is taken out from a negative electrode plate to outside of the battery. At least one type selected from an oligomer containing a cyclohexyl group and a phenyl group, a modified product of the oligomer containing a cyclohexyl group and a phenyl group, a polymer containing a cyclohexyl group and a phenyl group, and a modified product of the polymer containing a cyclohexyl group and a phenyl group is present on the surface of the positive electrode plate.

Nonaqueous electrolyte secondary battery and method for manufacturing the same

Growing community of inventors

Kasai, Japan

Hirofusa Tanaka