Accelerated lifetime assessment and estimation

 

The aim of the BALd project in the Battery Utilization Concepts competence cluster under the BMBF concept of the Battery Research Factory is to achieve accelerated lifetime prediction of lithium-ion batteries (LIB) by combining different laboratory tests for real-world applications. LIBs are reaching increasingly longer lifetimes, which leads to classic battery tests taking up to several years. This is too long to be able to support development processes sufficiently. Within this project's scope, a concept is being developed that will make it possible to use accelerated aging measurements on lithium-ion cells after two weeks, after six weeks, and after three months to provide a qualitative forecast of future aging behavior in direct relation to the usage scenario. The aim is to achieve rapid feedback into the development process and a considerable acceleration of the latter. Aging tests serve as a basis, which on the one hand are accelerated by aggravating various stress factors (temperature, relaxation times, cycle depth, etc.) and on the other hand provide early results through the detailed investigation of aging indicators. The concepts are developed and designed together by different outstanding research institutes within Germany.

Critical points in the project are:

• Development of methodologies for accelerated lifetime prediction (e.g. stochastic based step-stress methods).
• Accelerated life characterization of different stress factors (temperature, pressure, cycle depth, pause times etc.)
• Exploration of valid transfer rules between accelerated and real aging
• Investigation of path dependence between stress factor
• Accurate detection of side reactions by novel methods such as float current measurement and high-precision coulombmetry
• Development of a holistic aging and failure model taking into account all gained knowledge

With the results of BALd, development cycles can be shortened, innovation can be evaluated faster, and prototype production efforts can be reduced. The set of parameters generated will become part of the "electronic cell passport" developed in collaboration with the other clusters. The methods developed here can additionally be applied directly in the research factory. To facilitate the establishment, an investigation of LIB from the research factory or other FFB research production lines with the methods developed in this project is planned.

 

The aim of the BALd project in the Battery Utilization Concepts competence cluster under the BMBF concept of the Battery Research Factory is to achieve accelerated lifetime prediction of lithium-ion batteries (LIB) by combining different laboratory tests for real-world applications. LIBs are reaching increasingly longer lifetimes, which leads to classic battery tests taking up to several years. This is too long to be able to support development processes sufficiently. Within this project's scope, a concept is being developed that will make it possible to use accelerated aging measurements on lithium-ion cells after two weeks, after six weeks, and after three months to provide a qualitative forecast of future aging behavior in direct relation to the usage scenario. The aim is to achieve rapid feedback into the development process and a considerable acceleration of the latter. Aging tests serve as a basis, which on the one hand are accelerated by aggravating various stress factors (temperature, relaxation times, cycle depth, etc.) and on the other hand provide early results through the detailed investigation of aging indicators. The concepts are developed and designed together by different outstanding research institutes within Germany.

Critical points in the project are:

• Development of methodologies for accelerated lifetime prediction (e.g. stochastic based step-stress methods).
• Accelerated life characterization of different stress factors (temperature, pressure, cycle depth, pause times etc.)
• Exploration of valid transfer rules between accelerated and real aging
• Investigation of path dependence between stress factor
• Accurate detection of side reactions by novel methods such as float current measurement and high-precision coulombmetry
• Development of a holistic aging and failure model taking into account all gained knowledge

With the results of BALd, development cycles can be shortened, innovation can be evaluated faster, and prototype production efforts can be reduced. The set of parameters generated will become part of the "electronic cell passport" developed in collaboration with the other clusters. The methods developed here can additionally be applied directly in the research factory. To facilitate the establishment, an investigation of LIB from the research factory or other FFB research production lines with the methods developed in this project is planned.

 

Duration

1st December 2020 to 30th November 2023

 

Funding

The BALd project is funded by the German Federal Ministry of Education and Research (BMBF) under the funding code 03XP0320A as part of the BMBF competence cluster "Battery Utilization Concepts".

 

Partners

• Institute for Thermal Process Engineering (TVT) KIT in Karlsruhe

• Research Group for Electromobility and Adaptive Systems (ILS) at Ingolstadt University of Technology

• Chair of Electrical Energy Storage Technology (EES) and the Chair of Vehicle Technology (FTM) at the Technical University of Munich

• Accumulators Group at the Centre for Solar Energy and Hydrogen Research (ZSW)

• Institute for Statistics and Business Mathematics (ISW) at RWTH Aachen University