POWER STORAGE DEVICE BINDER COMPOSITION, POWER STORAGE DEVICE ELECTRODE SLURRY, POWER STORAGE DEVICE ELECTRODE, AND POWER STORAGE DEVICE

Provided is a binder composition for an electrical storage device, which is excellent in adhesiveness and can improve the charge-discharge durability characteristic of an electrical storage device. The binder composition for an electrical storage device includes: a polymer (A); and a liquid medium (B), wherein when a total of repeating units in the polymer (A) is defined as 100 mass %, the polymer (A) contains 1 mass % to 40 mass % of a repeating unit (a1) derived from an unsaturated carboxylic acid ester having an alicyclic hydrocarbon group, and 45 mass % to 90 mass % of a repeating unit (a2) derived from an unsaturated carboxylic acid ester having an aliphatic hydrocarbon 10 group excluding the unsaturated carboxylic acid ester having an alicyclic hydrocarbon group, and wherein the polymer (A) shows a swelling ratio of 120 mass % or more and 200 mass % or less when immersed in a solvent, which is formed of propylene carbonate and diethyl carbonate at a volume fraction of 1:1, under conditions of 70° C. and 24 hours.