DuPont Mobility & Materials has introduced new eCool technology for extrusion of multilayer cooling lines positioned inside and outside the high voltage battery pack in xEV. It has also launched a combined material-process-service solution for overmolding bus bars with Zytel HTN material.

At the upcoming K 2022, DuPont Mobility & Materials will showcase these and other cutting-edge solutions and technology innovations.

New technology delivers performance and sustainability for cooling lines

The new eCool technology addresses the challenge posed by increased cooling line requirements in xEVs, a direct result of the vital need to manage heat and energy for maximum battery operation, safety, and range.

Electric vehicles can require up to three times the length of cooling lines found in ICE systems. For these large components, engineers are challenged with finding a more sustainable solution that will still hold up to cooling fluids.

Innovative multilayer construction offers significantly improved design freedom and lower GWP for xEV cooling lines.

DuPont eCool technology, based on the company’s Zytel LCPA Long Chain Polyamide grades co-extruded with thermoplastic olefin elastomer, presents an alternative to current, heavier options such as thick EPDM rubber hoses and other thermoplastic assemblies. The solution not only removes weight but also better resists a wide range of EV cooling fluids while remaining cost competitive.

In addition, DuPont has assessed that its eCool solution can significantly reduce Global Warming Potential (GWP) of these cooling tubes by over half compared to monolayer PA12 tubes. It can be easily processed via extrusion and thermoforming as well.

Production-level support for eCool technology is available at DuPont’s Center of Excellence in Geneva, as well as at other application development centers throughout the globe.

This includes advanced CAE/FEA simulation, extrusion trials, support for post-processing, welding and testing for burst pressure, mechanical evaluation of properties before and after air and chemical aging, salt stress cracking, cold impact resistance, and bend testing.

Solution streamlines bus bar overmolding for high voltage components

DuPont Mobility & Materials is breaking new ground for manufacturers of xEV components with a combined material-process-service solution for overmolding bus bars with Zytel HTN material.

Bus bars are a workhorse component essential for distributing power in xEV batteries, motors, and power electronics. With the right materials, a bus bar can enhance a battery’s thermal management and power distribution systems. However, it must be adequately insulated if the battery overheats, a condition known as thermal runaway.

Bus bars within xEV batteries must meet several requirements, including:

•Resistance to thermal runaway without loss of function

•Qualification via demanding thermal cycling and electrical tests

•Efficient production to reduce manufacturing time and cost

•Stable orange color to indicate high voltage, even after prolonged exposure to high temperatures

Utilizing a host of production equipment, lab testing, and engineering capabilities at these facilities, the company has fine-tuned an overmolding process for bus bars that incorporates Zytel HTN material along with robust technical and processing support.

Zytel HTN raises the performance of bus bars for xEV high voltage components.

Zytel HTN has been identified as a material solution in this area. For example, safety standards dictate that bus bars maintain a stable orange color indicating high voltage, even after repeated exposure to high heat. Zytel HTN accelerated aging testing shows no noticeable color shifts, even at 130°C. It also contributes insulative properties for safer thermal runaway, and easily overmolds onto aluminum or copper, the most common bus bar metals.

Additionally, Zytel HTN insulation materials for bus bars resist multiple thermal shock cycles (typically 1000 cycles) at the temperatures (-40°C to 150°C) normally needed for motors and power electronics applications. This means the material resists cracks after being overmolded onto metal conductors.

Further, the material has excellent chemical resistance to the fluids used for thermal management and a high comparative tracking index (CTI) at elevated temperatures.