A battery cell, a battery unit, an electrical device, and an energy storage device

Abstract

A battery cell comprising a casing and a stacking cell, wherein the stacking cell is housed in the casing, the casing comprising a soft packaging material; wherein the stacked cell comprises a positive electrode plate, a negative electrode plate and a membrane, wherein the positive electrode plate comprises a positive current collector and a positive membrane layer arranged on at least one side of the positive current collector, wherein the positive membrane layer comprises lithium-containing transition metal phosphate particles that are at least partially coated with carbon material; where, in the fully discharged state of the battery cell, the thickness of the positive membrane layer on one side is denoted by H, where H is 70 µm to 120 µm; wherein the positive membrane layer comprises a first region extending from the surface on a side of the positive membrane layer facing away from the current collector to a distance of 20 ± 5 µm within the positive membrane layer, wherein in a cross-section of the first region along the thickness direction of the positive electrode plate the area fraction of the particles with a particle size R1 satisfying R1 ≥ 1000 nm is 10% to 40% in the first region, based on the total area of ​​the particles in the first region; wherein the membrane comprises a base and an adhesive layer arranged on at least one side of the base, which is located between the base and the positive electrode plate and / or the negative electrode plate and is a continuous layer with a pore structure.

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