M-ERA.NET 2021 COOL BATMAN

Battery thermal management system based on high power density digital microfluidic magnetocaloric cooling

In recent decades, the increase in lithium battery production has resulted in an 85% reduction in price, making electric vehicles and energy storage viable for the first time in history. In addition, lithium batteries are expected to be important in decreasing dependence on fossil fuels.

However, a major drawback lies in the narrow temperature range in which batteries operate at maximum efficiency without degrading.

There are two important aspects to battery thermal management (BTMS): the cooling technology has to be efficient and compact.

Most BTMS are still based on vapour compression technology, which involves environmentally harmful gases. There is a huge scientific effort to find more environmentally friendly and efficient cooling systems, and among them are those based on the magnetocaloric effect.

In spite of the numerous studies carried out to date, the devices based on this effect present problems due to inefficient heat transfer and hydraulic losses (linked to the cooling fluid).

The objective of the COOL BATMAN project is to get a basic understanding of the dynamic thermal behaviour of two different physical effects that will be coupled with the aim of achieving an efficient and compact cooling device.

For this purpose, a magnetocaloric material will be coupled to a dielectric substrate with electro-wetting properties (EWOD).

The EWOD phenomenon is based on wettability of liquid droplets on a dielectric solid surface: by varying the applied potential it is possible to manipulate (even move) small fluid droplets.

Fast manipulation with subsequent movement of a small volume of liquid serving to transport heat through the magnetocaloric material (instead of a continuous fluid flow) can result in a drastic reduction of hydraulic losses and a significant reduction of the amount of magnetocaloric material required, resulting in a more compact and efficient cooling device.

In this device, the liquid droplets would operate as thermal switches in which the droplet would absorb heat at a given location in the magnetocaloric material and through a fast movement would release it at another given location (heat sink).

Thus, the main goal of the project is to design, develop and test a compact cooling device based on the coupling of magnetocaloric and electromotive effects (MC/EWOD) that is suitable for integration as a temperature control device for lithium batteries.

The project concept enables the use of energy-efficient magnetocaloric cooling as a disruptive and green technology for battery applications as one of the sustainable energy supply technologies.

Magnetocaloric systems help to drastically reduce greenhouse gas emissions once established as an alternative to vapour compression.

The main result is the development of a new magnetocaloric cooling principle through the application of EWOD (digital microfluidic) thermal switches.

The results of the COOL BATMAN project are of immediate interest to the BTMS, since battery thermal management is one of the bottlenecks for the efficient operation of modern batteries.

Direct impact on the future production line

Miniaturisation will reduce the amount of magnetocaloric and magnetic materials needed per kilowatt of power.

Solid magnetocaloric materials can be recycled and reused.

COOL BATMAN could replace the ubiquitous vapour compression technology.

More efficient battery operation and extended battery life.

COOL BATMAN would impact and support the growing production of lithium-ion batteries.

It is expected that in the future the research results of the COOL BATMAN project could be used in the e-mobility sector (automotive, marine, rail, etc.).

If you are interested in finding out more about the COOL BATMAN project and its application, please send an email to
functionalmaterials@ub.edu

Contact information

The COOL BATMAN consortium consists of specialists in complementary fields, specially qualified to achieve the main objective of the project.

The consortium is made up of four institutions, where LAHDE —the Urban Refrigeration and Energy Laboratory— acts as a leading organization.

The members of the consortium are: