Power storage device binder composition, power storage device electrode slurry, power storage device electrode, and power storage device

A binder composition for an electrical storage device, comprising:

• a polymer (A);
• and
• a liquid medium (B),
• wherein, with respect to 100 mass % in total of repeating units contained in the polymer (A), the polymer (A) contains:
• 15 mass % to 60 mass % of a repeating unit (a1) derived from a conjugated diene compound;
• and
• 1 mass % to 10 mass % of a repeating unit (a2) derived from an unsaturated carboxylic acid,
• wherein tan δ (loss elastic modulus/storage elastic modulus) in dynamic viscoelasticity of the polymer (A) has one peak top in a range of from −40° C. or more to less than 50° C., and has one peak top in a range of from 50° C. or more to 150° C. or less, and
• wherein, when the tan δ at the peak top in the range of from −40° C. or more to less than 50° C. is represented by tan δ(Tp1), and the tan δ at the peak top in the range of from 50° C. or more to 150° C. or less is represented by tan δ(Tp2), a relationship of the following expression (1) is satisfied,
• tan δ(Tp2)/tan δ(Tp1)≥0.5 (1).