SECONDARY BATTERY, BATTERY MODULE, BATTERY PACK AND ELECTRIC DEVICE

Provided are a secondary battery, a battery module, a battery pack and an electric device. The secondary battery includes an electrode assembly and an electrolytic solution configured to infiltrate the electrode assembly, wherein the electrode assembly includes a negative electrode plate, a separation film and a positive electrode plate, and the negative electrode plate includes a negative electrode current collector and a negative electrode material layer located on at least one surface of the negative electrode current collector; and by setting a tortuosity of the negative electrode plate as τ, the τ satisfies Formula I below: τ=0.5(ε) Formula I (2τ)+6≤σ≤(2τ)+10 Formula II. Therefore, the secondary battery has an excellent fast-charging performance.