End-of-charge voltage

If a complete cell is charged to, e.g., 4.1 V, then the potential Z carbon of the fully lithiated negative electrode will be about 0.1 V vs. Li/Li+. Therefore, the potential Eoxiie of the fully charged positive electrode in this example will be 4.2 V vs. Li/Li+. Needless to say that this trivial relationship must be remembered when data for half cells (vs. metallic lithium) are compared to the data for complete cells. An important consequence of this trivial relationship is the potential excursion of the counterelectrode in the case of an anomalous behavior of the carbon electrode (and vice versa). Imagine that, in the previous example the potential of the carbon would shift to 0.3 V vs. Li/Li+ due to a malfunction of the carbon electrode. If the end-of-charge voltage of the complete cell would be the same, namely 4.1V, then the potential of the positive electrode would be 4.4 V vs. Li/Li+. In such a case, the safety of the entire cell could be compromised. 

Fig. 9.17. End-of-charge voltage (CC finishing step) and end-of-charge current (CV step) as function of cycle-life for 12-V/50-Ah VRLA battery using the standard Optima lUI recharge algorithm.

Figure 1 depicts the increase in capacity of the cylindrical 18,650 cell (18 mm in diameter and 65.0 mm long) from 1992 to 2006. The early LIBs had a capacity of 800 mAh and an end-of-charge voltage of 4.1 V. The initial cells used hard-carbon anode materials which had a capacity of about 200 mAh/g, and the LiCoO had a capacity of nearly 130 mAh/g due to 4.1 V charging voltage. The early lithium-ion cells used a propylene carbonate-based electrolyte. However, energy density of LIB... 

Is based on electrochemical characteristics energy, capacity, EMF, internal resistance, end of charge voltage, etc... 

In low-cost systems, there might be some differences in the requirements or functions for the BMS. Especially for a low number of cells in series (e.g. 12 V systems with four cells in series), some battery system manufacturers propose a simple external undervoltage shutoff circuit and a charger with controlled end-of-charge voltage. 

Therefore, the voltage evolution during the charge process is represented by Equation 9.38, up to the start of gassing Ug J and by Equation 9.42 for overcharging > Uga) until the end of charge voltage is reached. 

The voltage profile of a sealed nickel-cadmium batteries is different from the one for a vented one, as illustrated in Fig. 28.26 The end-of-charge voltage for the sealed battery is lower. The negative plate does not reach as high a state of charge as it does in the vented construction because of the oxygen recombination reaction. 

Electrical Continuous chaige Chaige at 2(TC per manufacturers recommendation, hold at end of charge voltage for 28 days. 

End Voltage The prescribed voltage at which the discharge (or charge, if end-of-charge voltage) of a battery may be considered complete (also cutoff voltage). 

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