Overcharge ZEBRA

The second electrolyte, the melt of sodium aluminum chloride, provides another advantage for the ZEBRA system. This second electrolyte makes the system tolerant to overcharge and overdischarge. In the overcharge reaction NaAlCl4 reacts with nickel to form sodium, nickel chloride, and... 

The safety of the ZEBRA battery has been proven extensively by abuse testing overheating, overcharging, short-circuiting of battery terminals and of cell groups, crash tests on the battery itself by dropping it at 50 km h 1 onto a pole or spike, and crash tests of cars with built-in ZEBRA batteries at 50 kmh-1 [10]. The results of abuse testing prove the ZEBRA battery to be a safe battery system. 

Zebra batteries have been subjected to a series of tests to demonstrate their ruggedness and safety. These include overcharge, short circuit, overheating and vibration and shock. Drop testing to simulate the effect of a... 

Battery safety is so important for mobile and vehicle apphcations. Especially for vehicles, on the road, accident likely becomes heavy, and the crash accident should not bring more danger by release of the energy stored in the cells. And various tests are usually conducted. In ZEBRA battery case, test results were reported. Crash of an operative battery against a pole with 50 km/h, overcharge test, overdischarge test, short circuit test, vibration test, external fire test, and submersion of the battery in water have been specified and performed [6]. The ZEBRA battery did pass all these tests owing to its four-barrier safety concept [7, 8] chemical aspects, cell case, thermal structure, and battery controller. 

Overcharge reaction. The charge capacity of the ZEBRA cell is determined by the quantity of salt (NaCl) available in the cathode. In case a cell is fully charged and the charge voltage continues to be applied to the cell for whatever reasons, the liquid salt NaAlCU supplies a sodium reserve following the reversible reaction... 

Figure 21.3 Overcharge and overdischarge reactions of the ZEBRA cell.

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