A Model-Based Virtual Sensor for Condition Monitoring of Li-Ion Batteries in Cyber-Physical Vehicle Systems

Figure 1

ICA (a) and DVA (b) curves of a new LiFePO₄ battery are drawn in black. These curves are superimposed in red for the same battery after 3000 charge-discharge cycles. The diagnostic of the battery is immediate when these curves are available. (c) Current and voltage during the experimental OCV determination by voltage relaxation of a typical LiFePO₄ battery. The relaxation time between partial charges is on 4 h. Pulses are of 10% of the battery capacity (42 Ah). OCV, IVA, and DVA can be measured at the laboratory, but the procedure is long, lasting more than four days in batteries with higher capacities. A soft sensor is sought that produces these curves through data sampled with on-vehicle sensors.

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