Abstract: The present invention discloses a type of novel material compositions for hydrogen storage. The material compositions includes a hydrogen storage Laves-phase alloy which has a material composition represented by A.sub.1-X B.sub.X C.sub.Y where A=(Zr or Hf).sub.1-X1 Ti.sub.X1 and X1 has a value between zero to one, B=La, Ce, Pr, Nd and mixed rare earth, alkaline, or alkaline earth metallic element, C=V.sub.Y1 Ni.sub.Y2, where Y1 has a value between zero to 0.8, Y2 has a value between 1.3 to 3.0, and X has a value between zero to 0.2 and Y has a value between 2.0 to 3.0. In a preferred embodiment, when the value of X is greater than zero, the Laves-phase alloy includes a plurality of B--Ni clusters.

Abstract: The present invention discloses a thermal protection device which includes a temperature limiting switch such as a thermostat to switch off a charging loop to a rechargeable battery to prevent overheating in the cells of the rechargeable battery. The thermal protection device further includes a parallel loop for continuously conducting a discharging current when the charging loop is switched off. The parallel loop include a diode which allows current to flow only in the opposite direction of the charging current through the temperature limiting switch. The power output from the rechargeable batteries is therefore not affected by the switching on and off of the temperature limiting switch for controlling the charging operations.

Abstract: A rechargeable battery pack which includes several battery cells. Each cell has a positive electrode and a negative electrode connected in series. Each of the battery cells further includes a reverse polarity protection device. The protection device includes a low voltage switch connected between the positive electrode and the negative electrode of the battery cell. The low voltage switch is switched on to become a short circuit when a voltage difference between the positive electrode and the negative electrode for each of the battery cells is lower than a threshold switch-on voltage such that the each of the battery cells is bypassed and protected by conducting a current through the short circuit in the low voltage switch.