Nickel Metal Hydrive Battery For Electric Vehicles :: essays research papers

Electric vehicles can take in us in many ways. Comparing with the internal combustion engine, EVs befoolt cause pollution when operating. They can run in a long period of time. Economically, because these vehicles using onslaught, they reduce the oil import and the imbalance trading in the US and also the users save a green goddess of money. The cells used for these vehicles are called Nickel surface hydride battery which are very luxuriously power, long life, quick charge and easy to maintain. CELL reply The NiMH battery stores hydrogen as a reaction product in the solid phase. The anode electrode contain hydrogen material that can allow electrochemical storage and release of hydrogen during charge and discharge. The cathode electrode is reversible between Ni(OH)2 and atomic number 28 oxyhydroxide (NiOOH). At some(prenominal) electrode, oxidation-reduction reactions take place in an saltlike medium consisting of 30% by weight KOH in water. When charging, Ni(OH)2 at the confirming electrode be practices oxidized and the metal hydride becomes reduced. In fact, the hydrogen which was separated from water come to react with the metal in the negative electrode to form MH. On the other(a) hand, the hydroxyl ion ( from water) reacts with Ni(OH)2 at the positive electrode to form NiOOH. Ni now transport from +2 to +3.M + H2O + e = MH + OHNi(OH)2 +OH = NiOOH + H2O + eFrom comparability (1) and (2) there is no net change in electrolyte quantity or intentness over the charge and discharge cycle. We can see that it is contrary from other alkaline electrode such as NiCd which water is produced at both electrode during charge and used up during discharge. In the NiMH battery, the constant average concentration can reduce the corrosion and swelling. MATERIAL REQUIREDBecause the NiMH battery compulsion to store a large amount of hydrogen to produce high energy, it is desirable to have high electrode capacity. Importantly, in the desire of MH, the range of metal to hydrogen hold fast strengths must be from 6 to 12 kcal /mol. If the bond strength is in addition weak, hydrogen leave alone not react with the alloys and will be evaporate as a gas. If the bond strength is too large, the MH electrode becomes oxidized and does not store hydrogen reversibly. Furthermore, the power output of the battery depend on the electrochemical kinetics and transport processes which are knobbed in the use of the hydride material.