Battery cell, battery and electric device

A battery cell, comprising:

• a casing, comprising a bottom wall and first side walls connected with the bottom wall, wherein an inner surface of the bottom wall is connected with an inner surface of each of the first side walls by a first circular arc transition surface;
• an electrode assembly, accommodated in the casing, wherein the electrode assembly comprises electrode plates and a separator;
• a first insulating member, comprising first partition portions configured to separate the electrode assembly from the first side walls;
• and
• a second insulating member configured for separating the electrode assembly from the bottom wall,
• wherein:
• in a thickness direction of the second insulating member, the separator has a stacked part located between the electrode plate and the second insulating member;
• and
• a radius R1 of the first circular arc transition surface, a thickness a1 of each of the first partition portions, a thickness b of the stacked part, and a thickness c of the second insulating member satisfy following relationship:
• R
• ⁢
• 1
• ≤
• (
• c
• +
• b
• )
• 2
• +
• 4
• ⋆
• (
• a
• ⁢
• 1
• )
• 2
• +
• [
• (
• a
• ⁢
• 1
• )
• ⋆
• (
• c
• +
• b
• )
• ]
• 1
• /
• 2
• .