(JP10308210-A)      In a battery containing positive electrode and collector films, a host metal foil for forming a negative electrode, an alkali metal ion conductive electrolyte (preferably a polymer electrolyte) and an alkali metal ion source, the host metal foil includes voids in a number and disposition providing local accommodation of foil expansion and thus prevention of any cumulative change in the foil plane during initial alloy formation between the host metal and the alkali metal provided by the alkali metal ions. Also claimed is a process for producing the above battery.    USE -   Especially as a polymer electrolyte battery of lithium ion type.    ADVANTAGE -   The negative electrode alloy is in a dense (non-composite) form and provides local stress relaxation during alloy formation preferably after initial operation of the battery. The design allows optimisation of the energy density per unit volume, due to the dense zones, and of the battery power by control of the anode void density and the presence of polymer in the residual anode spaces after alloy formation and expansion. Additionally, when a polymer electrolyte is used, electrolyte penetration into the dense parts of the anode is minimised to maintain high electrical contact quality within the alloyed structure.    (EP872902-B1)      In a battery containing positive electrode and collector films, a host metal foil for forming a negative electrode, an alkali metal ion conductive electrolyte (preferably a polymer electrolyte) and an alkali metal ion source, the host metal foil includes voids in a number and disposition providing local accommodation of foil expansion and thus prevention of any cumulative change in the foil plane during initial alloy formation between the host metal and the alkali metal provided by the alkali metal ions. Also claimed is a process for producing the above battery.    USE -   Especially as a polymer electrolyte battery of lithium ion type.    ADVANTAGE -   The negative electrode alloy is in a dense (non-composite) form and provides local stress relaxation during alloy formation preferably after initial operation of the battery. The design allows optimisation of the energy density per unit volume, due to the dense zones, and of the battery power by control of the anode void density and the presence of polymer in the residual anode spaces after alloy formation and expansion. Additionally, when a polymer electrolyte is used, electrolyte penetration into the dense parts of the anode is minimised to maintain high electrical contact quality within the alloyed structure.    (US6265099-B1)      In a battery containing positive electrode and collector films, a host metal foil for forming a negative electrode, an alkali metal ion conductive electrolyte (preferably a polymer electrolyte) and an alkali metal ion source, the host metal foil includes voids in a number and disposition providing local accommodation of foil expansion and thus prevention of any cumulative change in the foil plane during initial alloy formation between the host metal and the alkali metal provided by the alkali metal ions. Also claimed is a process for producing the above battery.    USE -   Especially as a polymer electrolyte battery of lithium ion type.    ADVANTAGE -   The negative electrode alloy is in a dense (non-composite) form and provides local stress relaxation during alloy formation preferably after initial operation of the battery. The design allows optimisation of the energy density per unit volume, due to the dense zones, and of the battery power by control of the anode void density and the presence of polymer in the residual anode spaces after alloy formation and expansion. Additionally, when a polymer electrolyte is used, electrolyte penetration into the dense parts of the anode is minimised to maintain high electrical contact quality within the alloyed structure.