Europe took a different tack. The Eurobat Guide for the Specification of Valve Regulated Lead-Acid Stationary Cells and Batteries defines design life as follows: “The design life is the estimated life determined under laboratory conditions, and is quoted at 20°C using the manufacturer’s recommended float voltage conditions.” 6
Second-life batteries (SLBs) can be used for a variety of applications. For example, the retired batteries can be used to provide charging services for an EV charging station [7, 8]. However, their use as stationary battery energy storage systems (BESSs) is more common.
The continuous, dotted and dashed lines represent the cases without batteries, with lead-acid batteries, and with second-life Li-ion batteries, respectively It can be observed that the emission’s slope changes after the first life of the battery in the vehicle (year 10 in Fig. 3) proving how it strongly depends on the second-life application.
Such batteries may achieve routinely 1500 cycles, to a depth-of-discharge of 80 % at C /5. With valve-regulated lead–acid batteries, one obtains up to 800 cycles. Standard SLI batteries, on the other hand, will generally not even reach 100 cycles of this type. 4. Irreversible formation of lead sulfate in the active mass (crystallization, sulfation)
On the other hand, at very high acid concentrations, service life also decreases, in particular due to higher rates of self-discharge, due to gas evolution, and increased danger of sulfation of the active material. 1. Introduction The lead–acid battery is an old system, and its aging processes have been thoroughly investigated.
In this sense, it is important to note that the capability of a battery to be used in a second-life application strongly depends on the degradation of the battery at the end of the EV life (i.e., for a capacity below 80 %).