ZEBRA open-circuit voltage

Figure 10.5 ZEBRA open circuit voltage (OCV) depending on the status of charge (SOC).

ZEBRA cells have a high open-circuit voltage (OCV) of 2.58 V at 300 °C. The temperature dependency of the OCV is shown in Fig. 2. 

Figure 2. Open-circuit voltage of the Zebra cell versus temperature.

Electrical Networking. During the lifetime of a battery, individual cells may fail. Such an occurrence will result only in the reduction of the open circuit voltage by 2.58 V per cell failure because the failure mode of ZEBRA cells is an internal short (due to the reaction of the secondary liquid electrolyte with sodium forming a solid aluminum shunt). Because of this characteristic, long series chains with 216 cells and 557 V can be built. Intercell connections or voltage taps are not necessary. 

The zebra cell is a related cell that possesses much less damage potential in this respect [695]. The solid electrolyte is the same as in the Na-S battery, and the operating temperature is similar. However, the cell reaction comprises the reaction of Na with NiCl2 to Ni and NaCl, which is contained in a NaAlCU melt (open circuit voltage per cell 2.6V). If the electrolyte ceramic breaks, Na reacts with NaAlC to yield Al. The short circuit that occurs ensmres that the cell chain maintains its function even if 5% of the cell has been destroyed in this manner. 

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See also in sourсe #XX -- [ ]

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