Cooling agent extends service life of traction batteries
Lithium-ion batteries are quite sensitive to temperature variations. Their optimum temperature range is between 20 and 35°C. But already during a short summer ride the battery can heat up beyond this limit, potentially causing significant damage. If such a battery is operated at 45°C instead of 35°C, the service life will be reduced by 50%. For this reason, traction batteries require a temperature management. Today's batteries are either not cooled at all - with the abovementioned consequences. Or they are cooled by air, which however is not regarded as a satisfying solution. Air has a low thermal capacity and is a poor thermal conductor. In addition, the battery cells need a relatively large distance between each other to enable the designers to implement air conducts.
Researchers from the Fraunhofer Institute for environmental, safety and energy technology (UMSICHT) in Oberhausen (Germany) have developed a cooling agent with excellent properties to cool batteries. CryoSolplus is a dispersion, consisting of water, paraffin, stabilizing surfactants and small quantities of the antifreeze agent glycol. Since its thermal capacity is three times higher than water, the storage tank can be much smaller than the tank of a water-cooled system with comparable performance. In addition, CrySolplus features good thermal conduction; the heat can be transported away from the battery calls quickly. The additional costs are moderate; according to UMSICHT they amount to some 50 to 100 euros per vehicle.
The cooling agent functions as follows: As CryoSolplus absorbs heat, the paraffin globules melt - they become drops and store the heat. As soon as the solution cools off, the globules solidify again. Thus, the effect of CryoSolplus is based on a phase change. "The challenge was to get the dispersion stable enough", said UMSICHT scientist Tobias Kappels. The globules must not clump and, since they are lighter than water, they must not concentrate at the surface. This is why the researchers added surfactants: They accumulate at the globules and thus form a protecting cover.
The next research step will be to equip a test vehicle with the new cooling agent.
- Reinvented Li-ion cell costs 50% less to produce
- Electrolyte additives prevent fires in next-generation lithium batteries
- NiZn battery is validated for 12-V automotive use
- Vehicle energy test system is optimised for 48 volts
- Bosch adjusts course for future mobility requirements
- Four-quadrant, bipolar operation voltage drop simulation of vehicle batteries
- MOST – a gigabit data backbone for future car generations?
- Automotive chip reliability: A matter of design methods
- LG Chem clinches lithium-ion battery contract for the e-Smart
- Verification tool automatically generates test cases
- Fraunhofer launches test centre for high-voltage batteries
- Scalable electric powertrain targets utility vehicles
- Are next generation EV batteries a step closer?
- General Motors targets Tesla with EV launches
- Daimler invests € 100 million in battery expansion
- Continental puts together holistic car HMI
- Continental demos new generation of e-powertrains
- Jaguar taps into brain waves to ensure driver attention
- Innovative brake concept cuts stopping distance
- Pedestrian Protection Assistance Systems - Meeting a testing challenge
- “Autosar should reflect electromobility challenges”
- SDK targets InfoADAS development
- Atmel on the Block
- 'Transparent' truck lets drivers behind it see road ahead
- Automotive King Redefines Future
- Synopsys IP speeds automotive SoC development
- Sensata climbs automotive MEMS ranking
- HMI design tool now available in a free version
- Do head-up displays lead the wrong way to safety?
- Ford in home stretch for automated driving
- A Smart Way to Drive ECU Consolidation
- Autonomous Driving: An Eye on the Road Ahead
- Automotive Designs Demand Low EMI Synchronous Buck Converters
- Intel helps to Turbocharge Infotainment Systems Designs
- Making cars safer through technology innovation
- Supplying DC input power for HEV testing
- NSR Noise Suppressors: Wirewound Resistors