New Energy is changing transportation rapidly. Our coating technology enables better fire protection of energy sources for electric vehicles.
The ecological sustainability crisis is driving innovation in all industries. In transportation a big change is happening in the area of energy sources. Fully electric cars using batteries, as well as heavy-goods vehicles and buses equipped with hydrogen pressure vessels are being rapidly introduced into the market.
Composites play a key role in the light-weighting of vehicles and they are increasingly used in applications regarding renewable energy. However, one of the priority problems that needs to be solved is the poor fire safety of composites. At the same time, new standards and requirements for ensuring sufficient fire performance are expected to be introduced to the market. China is currently very much in the driving seat when it comes to fire safety of new energy sources for the automotive industry, for both battery use and hydrogen cylinders.
The duration, intensity and location of a fire in an electric vehicle can make it harder to put the fire out compared to a traditional car. Fire can be caused by an extreme sudden heat build-up in lithium-ion battery systems (called thermal runaway). The main issue is ensuring that the battery housing remains structurally sound for as long as possible during a fire event. This needs to be taken into account when designing the vehicle, to allow sufficient time for passengers to escape. Traditional battery casings are made of aluminium, but the use of composites is increasing to lower the cost and weight. Manufacturers are evaluating how thick the composite needs to be, what should it be made of (thermoset or thermoplastic), and whether it can be used for the whole casing, or in combination with other materials.
One commercially-viable option to solve the problem with fire safety of composite battery casings is to use our innovative fire protective coatings. The results of our experiments show that our RED coating system can help to better protect a car battery casing against fire, for longer periods of time and to higher temperatures.
Composite Overwrapped Pressure Vessels (COPVs), currently used in electric-powered heavy-goods vehicles and in future for cars, form a potential risk for explosion. In the case of a fire event, a sudden thermal shock to the gas should be avoided and the pressure release valves should be allowed to function properly. The current European fire safety regulation is insufficient for vessels containing hydrogen as the current standard has been defined for natural gas (where the pressure and the risk of an explosion is far lower).
In the case of pressure vessels, our research focus has been on thermal insulation, and the results of our experiments show that thermal protection in the form of coatings applied to the vessel itself can provide the necessary structural integrity and temperature management for the gas.
Our R&D team have been testing different coating solutions on different substrates. The key target is to find a solution with optimal coating thickness in line with the selected substrate. We have already achieved promising results with both thermosets and thermoplastics. As an example, in the attached chart you can see the result of one of our recent experiments with, which makes us especially proud. We managed to control the heat transfer through a 3 mm PMMA glassfibre composite panel for a duration of 30 minutes when exposed to temperatures from 600-1000 ⁰C. Only a 1 mm thick 2-layer coating system was required to maintain and stabilise the temperature of the unexposed face of the panel to around 200 ⁰C.
Our RED coating system is based on two coating technologies complementing each other to offer unbeatable fire protection, both in terms of reaction and resistance to fire. hybridRED is a revolutionary ceramifying topcoat, and pureRED is a controlled intumescent primer-basecoat.
When exposed to fire, pureRED forms a thick and stable foamed char to control both heat release and heat transfer. On top of this char, hybridRED forms a self-supporting barrier – a ceramic shield, which can withstand temperatures up to 1000 °C. The attached pictures show how our RED fire protection coating system behaves under extreme heat.
Our next webinar on Thursday 11th November will focus on the fire protection of composite materials for New Energy applications in the transport industries. Please join by sending a message to our Technical Business Manager Trevor Fielding, contact information below.
If you are interested in our previous webinars with focus on Railways & Rolling Stock and Construction, you can find recordings at www.finnesteri.fi/news-and-events/webinars.