Secondary batteries

Abstract

To provide a secondary battery that suppresses the decrease in liquid flow and improves high-rate performance. [Solution] The device comprises an electrode body 20 housed inside a housing and battery terminals electrically connected to the electrode body 20. The electrode body 20 has a flat shape formed by stacking and winding a positive electrode plate 4 and a negative electrode plate 5 with a separator 6 in between, and has arc portions on both sides in the longitudinal direction when viewed in the winding axis direction. The separator 6 consists of at least two layers, and the outermost layer facing outwards from the electrode body 20 has greater residual stress than the layers located inside the electrode body 20.

Claims

1. The electrode body housed inside the casing, The electrode body comprises a battery terminal electrically connected to it, The electrode body has a flat shape formed by stacking a positive electrode plate and a negative electrode plate with a separator in between and winding them, and has arc portions on both sides in the longitudinal direction when viewed in the winding axis direction. The aforementioned separator is, It consists of at least two layers, A secondary battery in which the outermost layer facing outward of the electrode body has greater residual stress than the layers located inside the electrode body.

2. The secondary battery according to claim 1, wherein the separator consists of three or more layers, and the residual stress decreases in stages from the outermost layer toward the innermost layer facing inward of the electrode body.

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