Okamoto E, Yoshida T, Fujiyoshi M, Shimanaka M, Takeuchi A, Mitamura Y, Mikami T
Department of Electronic and Information Engineering, School of Engineering, Hokkaido Tokai University, Sapporo, Japan.
ASAIO J. 1996 Sep-Oct;42(5):M332-7. doi: 10.1097/00002480-199609000-00005.
An implantable rechargeable battery is one of the key technologies for totally implantable artificial hearts. The nickel-metal hydride (Ni-MH) battery is promising for its high energy density of 1.5-2.0 times that of a nickel-cadmium battery. In this study, the effects of pulsatile discharge loads on the operating time and cycle life of Ni-MH batteries at 39 degrees C were studied. Two battery cells (TH-3M, 1,200 mAh, phi 14.5 x 49 mm; Toshiba, Tokyo, Japan) in series were charge/discharge cycled at 39 degrees C using a charge current of 1CA (1,200 mA) and then were fully discharged to 1.0 V/cell under either pulsatile discharge loads, which mimicked a systole (1 A for 0.3 sec) and a diastole (0.4 A for 0.3 sec), or a non pulsatile discharge load equivalent to the average of the pulsatile loads (0.7 A). Each cycle life test was interrupted on the 482nd cycle under pulsatile load, and on the 423rd cycle under non pulsatile load, because of malfunction of each battery charger. The tests showed that the pulsatile discharge cells had significantly (p < 0.001) less operating time (74.0 +/- 7.15 min) throughout the test period (up to 482 days) compared to the cells under equivalent non pulsatile discharge loads (93.7 +/- 7.74 min). The pulsatile-discharged Ni-MH cells provide significantly less operating time than the constantly discharged cells; the Ni-MH battery has an operating time of over 78 min and a cycle life of almost 500 cycles at 39 degrees C. In conclusion, the Ni-MH battery is feasible as an implantable back-up battery for a totally implantable artificial heart system.
可植入式可充电电池是完全植入式人工心脏的关键技术之一。镍氢（Ni-MH）电池因其能量密度比镍镉电池高1.5至2.0倍而颇具前景。在本研究中，研究了脉动放电负载对39摄氏度下Ni-MH电池工作时间和循环寿命的影响。将两个串联的电池单元（TH-3M，1200 mAh，φ14.5 x 49 mm；东芝，日本东京）在39摄氏度下以1CA（1200 mA）的充电电流进行充放电循环，然后在模拟收缩期（1 A持续0.3秒）和舒张期（0.4 A持续0.3秒）的脉动放电负载或相当于脉动负载平均值（0.7 A）的非脉动放电负载下完全放电至每单元1.0 V。由于每个电池充电器出现故障，脉动负载下的每个循环寿命测试在第482个循环中断，非脉动负载下在第423个循环中断。测试表明，在整个测试期间（长达482天），与等效非脉动放电负载下的电池单元（93.7 +/- 7.74分钟）相比，脉动放电的电池单元工作时间显著缩短（p < 0.001）（74.0 +/- 7.15分钟）。脉动放电的Ni-MH电池单元的工作时间明显少于持续放电的电池单元；Ni-MH电池在39摄氏度下的工作时间超过78分钟，循环寿命近500次。总之，Ni-MH电池作为完全植入式人工心脏系统的可植入备用电池是可行的。
