Generation 2 Lithium-Ion battery systems – Technology trends and KPIs

Abstract

Currently in series produced Lithium-Ion batteries – so called Generation 1 Lithium- Ion batteries – are used in high voltage battery applications in Hybrid, Plug-In-Hybrid and Electric vehicles. These Generation 1 battery systems proved already in series that Lithium-Ion batteries fulfill the high requirements regarding safety and electrical power in automotive applications. The real proof of the requested minimum 10 years life time requirement is not done yet. However, based on results from accelerated aging tests in laboratories one can expect that the Lithium-Ion batteries will fulfill the requested life time requirements of automotive field usage, too. Main targets of the development of the second generation of Lithium-Ion battery systems are decreased specific cost in EUR per kWh as well as increased volumetric and gravimetric energy density. Especially cost down will be the barrier to overcome in order to enable a wide use of electric drives in vehicles. Starting with a short overview of the actual status of Lithium-Ion battery technology this paper gives prognoses how the requirements to and the Key Performance Indicators of Generation 2 batteries will develop. Besides the already established high voltage systems used in Hybrid, Plug-In-Hybrid and Electric vehicles applications also new applications with a voltage level lower than 60 V are described. Such systems will be relevant for Boost-Recuperation-Systems (BRS) or Recuperation-Systems (RS). These systems are in direct competition to optimizing measures of conventional combustion engine powertrains. Hence an increased usage of such systems will only be possible when the demanding cost targets will be met. Focus of the paper will be batteries for the applications in Plug-In-Hybrids (PHEV), Electric vehicles (EV) and Boost-Recuperation-Systems (BRS).