| 摘要 |
In a lithium ion secondary battery, a negative electrode sheet is made of a metal foil and an active material layer containing active material particles. The negative active material layer includes a facing portion that faces a positive active material layer and a non-facing portion that does not face the same. The negative active material particles can be oriented in a magnetic field direction. When an angle between an extending direction of a major axis of the cross section of each particle and the metal foil is θ, the number of particles with the angle θ of 60°-90° is MA, the number of negative active material particles with the angle θ of 0°-30° is MB, and a value MA/MB is assumed to be an orientation degree (AL) of particles, the negative active material layer is made such that an orientation degree (AL1) in the non-facing portion is 1.2 or more. |
