Medical device having lithium-ion battery

A medical device comprising:

• a rechargeable lithium-ion battery for providing power to the medical device, the lithium-ion battery comprising:
• a positive electrode comprising a current collector and a first active material;
• a negative electrode comprising a current collector and a second active material;
• and
• an auxiliary electrode comprising a current collector and a third active material, the auxiliary electrode configured for repeated, selective electrical connections to the negative electrode when the potential of the negative electrode exceeds the potential of the auxiliary electrode by a predetermined value, the third active material providing excess capacity to the negative electrode when the auxiliary electrode is electrically connected to the negative electrode;
• wherein the first active material, second active material, and third active material are configured to allow doping and undoping of lithium-ions;
• and
• wherein the third active material exhibits charging and discharging capacity below a corrosion potential of the current collector of the negative electrode and above a decomposition potential of the first active material.

A medical device comprising:

• a rechargeable lithium-ion battery for providing power to the medical device, the lithium-ion battery comprising:
• a positive electrode comprising a current collector and a first active material;
• a negative electrode comprising a current collector and a second active material;
• and
• an auxiliary electrode comprising a current collector and a third active material, the auxiliary electrode configured for repeated, selective electrical connections to the positive electrode when the potential of the positive electrode falls below the potential of the auxiliary electrode by a predetermined value, the third active material providing excess capacity to the positive electrode when the auxiliary electrode is electrically connected to the positive electrode;
• wherein the first active material, second active material, and third active material are configured to allow doping and undoping of lithium-ions;
• and
• wherein the third active material exhibits charging and discharging capacity below a corrosion potential of the current collector of the negative electrode and above a decomposition potential of the first active material.