Rechargeable electrical energy storage device

Claim 1

In an electrically rechargeable electric energy storage system having (a) an electrode compartment means having an inlet means and an outlet means, said electrode compartment means having at least one cell having a positive halogen electrode and a negative metal electrode, wherein during the charge metal ions from an aqueous metal halide electrolyte are deposited onto the metal electrode and halogen is generated at the halogen electrode from the halide ions in the electrolyte, and during discharge the metal and halogen are converted back to the respective ions; (b) a storage compartment means having an inlet means and an outlet means and adapted to contain a halogen hydrate formed during the charging of the system; (c) a conduit means connecting the electrode compartment means and the storage compartment means, whereby electrolyte circulates between the electrode compartment means and the storage compartment means, the improvement which comprises valve controlled bypass means for said conduit means, said by-pass means having heat transfer means and halogen hydrate formation means serially included therein so as to cool the electrolyte which is circulating between the electrode compartment means and the storage compartment means through said conduit means, the halogen hydrate formation means being adapted to form halogen hydrate from the halogen and cool aqueous metal halide electrolyte solution during charging, said by-pass means being adapted to be disconnected from said conduit means after charging.