PLöPSS - Development of passive solutions to inhibit propagation in stationary storage systems

Duration: 01/2021 - 12/2023
Contracting Authority/ Sponsors:
Bundesministerium für Wirtschaft und Energie (BMWi)
Project Partners: RRC power solutions GmbH; Stöbich technology GmbH
Project Focus:
Thermisches Durchgehen einer 18650er Zelle in einem Batteriepack
© RRC power solutions GmbH
Thermal runaway of a 18650 cell in a battery pack.
Simulationsergebnisse einer Pouchbag-Zelle (Verteilung der volumetrischen Wärmeerzeugungsrate)
© Fraunhofer ISE
Simulation results of a pouchbag cell (distribution of volumetric heat generation rate).

The conversion of the power supply to renewable, mostly fluctuating energies requires temporary intermediate storage. Due to their specific advantageous properties, lithium-ion battery storage systems are particularly suitable for this purpose. However, the topics of safety and reliability for these batteries must be brought into the focus of development work. This is where the "PLöPSS" project comes in, in which the safety of lithium-ion battery storage systems is investigated, and propagation-inhibiting solutions are developed.

Specifically, design measures are to be taken to reduce the probability of thermal runaway, slow down the safety-critical processes and prevent leakage from the system housing in the event of an accident. For this purpose, the rapid heat and pressure developments are systematically treated experimentally and simulatively. Further the requirements for propagations-inhibiting materials and flame-retardant components, the housing and the gas flow paths are deduced.
 

The increasing conversion of the power supply to fluctuating renewable energies makes the offset between energy supply and energy demand more pronounced. The best way to compensate for these gaps is through intermediate storage. Various storage technologies can be considered, but the most widespread at present are electrical energy storage systems, led by lithium-ion battery systems due to their advantageous specific characteristics such as high efficiencies, high achievable cyclic and calendar lifetimes, and relatively high gravimetric and volumetric energy densities.

Due to the high energy density of lithium-ion cells, however, incorrect handling, failure of the control electronics, late manufacturing defects or age-related degradation or increase in internal resistance can cause a thermal runaway of single celland briefly emit very large amounts of heat, hot, partly toxic gases and a destructive pressure wave. The subsequent impact on the neighboring cells can also put them into critical states and thus cause so-called propagation.

Within the framework of this project, the partners involved are working on these highly relevant safety issues and developing solutions for stationary battery storage systems. For this purpose, the topics of rapid heat and pressure development will be systematically addressed using FEM simulations and experiments under defined laboratory conditions. To tackle heat generation, parameter studies on insulation materials, additional heat dissipating components and PCM (phase change materials) will be performed. The influences of ambient components such as conductor, emitted gases and possibly ejected solids will be taken into account. For the analysis of pressure wave propagation, the reference topologies of the storage are defined and the pressure development in this environment is simulated. This makes it possible to determine the requirements for the flame-retardant components, the housing and the gas flow paths. The validation is carried out both on test specimens of individual modules and on functional samples of the overall storage system. Finally, the operational neutrality of the safety measures used will be verified. The partners expect that the results of these investigations and developments will lead to a battery storage system whose safety level is significantly higher than today's standard. The understanding gained of the processes and the results obtained on propagation inhibition will be transferable to many other areas of application and will make a significant contribution to increasing safety in all areas of application of lithium-ion batteries.

More Information on this Topic:

Research Topic

Battery System Technology

Research Topic

Heat and Cold Storage

Business Area

Hydrogen Technologies and Electrical Energy Storage

Business Area

Energy-Efficient Buildings