Batteries

Summary

Durable and safe battery systems

We answer our customers´ thermal inquiries into battery cells, modules, and systems with a focus on thermal management, aging, and safety. We specialize in analyses of lithium-ion batteries for application in electric vehicles and stationary storage systems.

Thermal Management

Evaluation of battery thermal management systems for electric vehicles

Thermal management is a crucial factor for the performance, lifetime, and charging speed of batteries in electric vehicles. Thermal simulation enables quick evaluation of battery thermal management systems (BTMS) in terms of maximum temperatures and temperature gradients across a module, stack, or system during the design phase. 

 

We use 0D/1D-models (Modelica / Simulink) of batteries and their components and combine them with thermal fluid models from our model library TIL. We offer services using the following modeling methods:

  • Depiction of ohmic losses via impedance-based and simplified equivalent circuits
  • Calculation of multidimensional temperature fields and heat sources by suitable interconnection of 0D/1D models 
  • Use of battery models to evaluate different cooling and heating concepts (air, water, oil, refrigerant, heat pipes)
  • Integration into complete vehicle models

CFD and field calculation methods (Star CCM+, Ansys, OpenFOAM) are used for high-resolution, detailed evaluation of new cooling and heating concepts. For our customers, we perform detailed investigations into the following:

  • Promising cold plate designs with respect to heat transfer and pressure losses
  • Electronics and high-voltage components
  • Novel cooling concepts and structures

Using model reduction methods, we can convert 3D models into models that can be used in system simulations. Here, we draw on our experience in modeling and simulating typical cell types (pouch, prismatic, cylindrical) and various cell chemistries (NMC, NMCA, LFP, NCA). We develop models in close cooperation with our customers and research partners. The development of our models is based on measurement data, manufacturer data, or scientific publications.

Figure 1: Left: 3D temperature and velocity distribution for an exemplary battery module including cooling plate; right: 0D/1D modeling approaches and the resulting temperature distribution for a prismatic cell with bottom cooling

Thermal Safety

Thermal Runaway and Thermal Propagation

Fault-induced combustion of battery cells (thermal runaway) is a hazard associated with the use of lithium-ion batteries. The proliferation of thermal runaway in a module, stack, or system is called thermal propagation.

 

With physical as well as simplified empirical 0D/1D/3D models, we represent the following effects:

  • Relevant heat conduction paths

  • Released heat

  • Reactions taking place

  • Degassing flows

This enables us to evaluate various concepts, measures, and materials for preventing and limiting thermal runaway and thermal propagation. The corresponding models can then be used to optimize passive and active measures for safe modules and stacks using suitable algorithms.

 

Together with our research partners, we experimentally investigate the aging and thermal runaway of different battery cells and individual cell components. Using these results, we can derive, calibrate, and validate reaction and cell models, and identify physical and chemical mechanisms.

Contact

Your contact partner

If you have any questions regarding 3D-modeling of batteries, please contact:

Dr.-Ing. Björn Flieger

+49/531/390 76 - 255

Contact

Your contact partner

If you have any questions regarding 0D/1D-modeling of batteries, please contact:

Dr.-Ing. Andreas Varchmin

+49/531/390 76 - 263