Additives and Synthetic Base Oils Designed
for E-Mobility Lubricants
Battery Thermal Fluids
When Li-ion batteries get hot
Consumers are demanding BEVs that can be driven farther between charges and recharged quickly. BEV manufacturers are responding by using more Li-ion cells and higher voltages and currents to allow faster recharging. The increased heat generated during battery fast charging and discharging is problematic because Li-ion cells are sensitive to heat. The more powerful the batteries are designed, the more important it is to use the relatively complex cooling and refrigerant-based circuit.
For long life and reliability, it is essential that Li-ion batteries operate in their optimum temperature range of approximately 15-35 °C (60-95 °F). Their maximum tolerable temperature is around 60 °C (140°F), and Li-ion batteries undergo irreversible damage and break down near 90 °C (195 °F).
A solution for battery cooling: immersion cooling
EV battery thermal management using a non-conductive fluid in direct contact with the battery cells, commonly known as Direct Immersion Cooling, allows improved heat flow both into and out of the EV battery cells. Direct immersion cooling makes faster charging times possible by optimum pre-conditioning of the EV battery temperature prior to charging in cold conditions and then by removal of excess heat from the battery once the charging process is under way.
LANXESSThe success of direct immersion cooling depends on the quality of the thermal/cooling fluid which needs to be non-hazardous, non-conductive, chemically stable, easily pumped over a wide temperature range and compatible with all battery materials of construction. In addition the fluid should resist combustion if the battery is damaged by impact.
Important requirements:
- High flash point and low flammability
- Low viscosity and pour point
- High heat capacity and thermal conductivity
- Low electrical conductivity and high breakdown voltage
- Compatibility with metals, plastics, and elastomers
- Environmental profile: non-hazardous, biodegradable and recyclable
LANXESS
LANXESS offers a portfolio of different fluid technologies as immersion coolants.
- Polyalphaolefin (PAO) fluids which are of high purity, chemically inert, synthetic hydrocarbon fluids offering a good combination of thermal and electrical properties
- Polyol ester (POE) fluids based on LANXESS Hatcol® high purity ester fluid technology which, in addition to superior thermal and electrical properties, offer high fire resistance
- Phosphate ester (PE) fluids, based on the same fire resistant phosphate ester fluid technology as our industry leading LANXESS Reolube® fire resistant hydraulic fluids, offer the ultimate in fire and combustion protection in the event of accident damage or electrical failure
E-driveline fluids
The main challenge for EV drivelines is achieving a balance between decreasing wear and preventing copper corrosion. Both performance properties are critical to vehicle efficiency and range as well as fluid longevity.
'Wet' e-motor designs
Wet e-drivelines will dominate in the future, and the operating conditions will be more severe (higher temperatures, voltages, currents, and gear box speeds). Moreover, there are expectations for fluids with longer, even “lubed-for-life”, service.
BEVs with gear boxes that operate at higher speeds with no clutches require transmission fluids with much greater thermal stability, heat transfer, and electric properties than current products. Fluids need to provide even more protection from friction, wear and foaming in gear boxes plus be compatible with copper and insulating materials. Material compatibility is a major concern in wet designs as the transmission fluid will be in contact with the insulation protecting the copper windings of the e-motor.
Research and development
LANXESS focuses on developing a new generation of EP additives that are less reactive toward copper and have better stability to withstand high temperatures and provide long service life. With 65 technical staff members with approximately 200 test methods in our four laboratories and technical centers around the globe, we are working on product innovations that serve the future needs of the automotive industry.