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Readers may recall an article in the magazine last year, entitled “EV batteries pushed to their limits and beyond at Millbrook Proving Ground,” in which I discussed some of the durability and abuse testing that UTAC CERAM Millbrook carries out on electric vehicle batteries. Such is the scope and scale of battery testing at UTAC CERAM Millbrook that I was barely able to scratch the surface in just one article, so here I am again to cover some additional topics.
I’d like to focus this time on the evolution of safety testing, particularly in relation to battery abuse. At UTAC CERAM Millbrook we’ve been doing safety testing for 50 years, and over that period we’ve adapted our approach to accommodate new battery technologies. Much of the testing that we carry out today is in support of manufacturers’ green agendas, helping them to get more EVs safely to market.
To give manufacturers peace of mind, it is essential that we put their batteries through varied and rigorous test procedures. So the suite of battery safety testing at UTAC CERAM Millbrook includes mechanical impact and shock testing, altitude testing, turnover testing and drop testing.
Mechanical impact and shock testing
A mechanical battery shock test simulates sudden acceleration or deceleration due to an impact. This enables battery manufacturers to determine safety in the event of extreme scenarios on the road.
UTAC CERAM Millbrook has the capability to safely perform these dynamic impact tests on battery cells, modules and packs up to 2m x 1.4m x 1.5m indoors, and up to any size outdoors.
Altitude testing
Altitude testing is also important for determining battery safety, but from a different perspective. This testing is about ensuring that batteries will remain safe when transported by land, sea and air. Indeed, all lithium batteries must meet UN38.3 criteria before they are transported by any of these means. UTAC CERAM Millbrook's battery altitude test chamber, opened last year, has the ability to simulate unpressurised aeroplane space at altitudes up to 15,000m.
During a UN38.3 altitude test, the battery is stored in the chamber at 11.6kPa for an extended period (longer than six hours) to simulate the product shipping process. It is then inspected against a set list of criteria, including checking for any mass loss, leaking, rupture or venting.
Turnover
The opening of UTAC CERAM Millbrook's battery turnover facility – the first of its kind in the world – was in response to the growing demand from the electric vehicle market for safer batteries, as well as longer battery life and higher power output. Again, this serves to highlight the growing importance placed upon sustainable battery power that is safe and proven in as many different complex scenarios as possible.
Battery turnover testing simulates a rollover crash scenario on an electric vehicle battery pack. The facility brings to bear UTAC CERAM Millbrook's crash test experience, built over 50 years, in combination with battery testing know-how. The test itself can be combined with a simulated or real coolant leak to test the impact of the battery coolant in this situation.
Drop testing
The most recent addition to UTAC CERAM Millbrook's suite of battery test facilities is a 10m drop tower. The facility is located outdoors as an additional safety measure. Hopefully you’re beginning to see the picture emerging, with safety at the centre.
The drop tower is used to determine whether products are safe and operable after being dropped from heights of up to 10m. Users can simulate a fall from a forklift truck or from storage racking.
Strip down
After completing tests such as the ones outlined above, UTAC CERAM Millbrook's team safely strips the battery down to its component parts, measuring key parameters and removing the risks associated with customers doing this themselves.
For more information, visit millbrook.co.uk/ev-battery-testing
Read more from Peter in his white paper entitled “The impact of coolant choice on lithium-ion batteries” at millbrook.co.uk/ev-battery-testing/#coolants
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Content published by Professional Engineering does not necessarily represent the views of the Institution of Mechanical Engineers.