Abstract
We evaluated four kinds of rechargeable batteries (a Ni-MH battery, a Ni-Cd battery, a Li-ion battery using a graphite electrode, and a Li-ion battery using a non-graphitizable carbon electrode) by a life-cycle experiment using them as implanted back-up batteries in a totally implantable artificial heart system. Each of the batteries was charge/discharge cycled at 37-39°C using a charge current of 1CA, and fully discharged under either pulsatile discharge loads, which mimicked a systole and a diastole, or a nonpulsatile load equivalent to the average of the pulsatile load. The results showed that the Li-ion battery with a non-graphitizable carbon electrode provided a longer operating period (up to 2500 cycles) and a lower by 3°C than those of other batteries regardless of the discharge pattern, while each of the batteries had operating cycles of over 800, which is enough battery life to apply to the totally implantable artificial heart system.
