SOC estimation algorithm for Li-ion battery in electric or hybrid vehicles

Abstract

As over-charging and over-discharging can cause damage to batteries, to guarantee the stability and duration of batteries, it is necessary to avoid being over-charged and over-discharged. Therefore, knowing the batteries' state of charge (SOC) is essential. In this paper, the author describes in detail the procedure of building a SOC estimation algorithm. The SOC estimation algorithm is based on unscented Kalman filter. Moreover, changes of battery capacity and internal resistance are considered. The impact of these changes on the estimation accuracy is explored. Experiments on an Iron Phosphate Li-ion battery cell with real load were conducted to justify this method. This method was verified to be not only precise but also stable.

Recycling Strategies for Spent Consumer Lithium-Ion Batteries

“…After leaching, the solution is first cleaned by hydroxide precipitation. In this process, copper and aluminum impurities are precipitated with the addition of, e.g., NaOH [97]. For the subsequent extraction of precious metals from the solution, either further precipitation steps or solvent extraction are used [98].…”

“…Here, separation can be achieved by the unequal distribution of the two phases, where solvent extraction agents with high selectivity are used after leaching to separate specific transition metals from the leach solution [105][106][107]. The lithium then remains in the solution and can be precipitated, e.g., as lithium carbonate, by adding sodium carbonate [97].…”

Synthesis and Recyclability of Sheet-like Cobalt Carbonate Recovered from Spent Li-Ion Batteries Using a Simple Hydrometallurgy Process

“…In this process, H 2 O 2 is generally used as a reducing agent to convert Co 3+ to readily acid soluble Co 2+ ions [17,18]. A purification step is then generally needed to remove metal impurities dissolved at the leaching step, such as Al and Cu [19]. In order to separate the metals from each other, the solvent extraction method is used.…”

“…In contrast, chemical precipitation, which is based on the selective precipitation of the metal of interest by adjusting the pH of the leaching solution with a precipitating agent, is scalable, simpler and more environmentally-friendly compared to the solvent extraction method [25][26][27]. In the literature, NaOH is typically used as the precipitating agent to recover Co as Co(OH) 2 , while Na 2 CO 3 is used to precipitate Li + as Li 2 CO 3 [19,25]. However, the selective precipitation of CoCO 3 from a leaching Co/Li solution using Na 2 CO 3 is poorly described in the literature.…”