Lithium-lon batteries – the risks and what can be done about it

Whilst earlier this year the Government postponed its target to ban the sale of new petrol and diesel powered cars and vans from 2030 to 2035, it is clear that electric vehicles, and therefore Li-ion batteries, are here to stay. In 2022 new EV registrations were 40% higher than the year before, accounting for around 17% of all new cars sold in the UK, compared to 2% in 2019.

Not surprisingly therefore, risks associated with Li-ion batteries feature on most insurers’ ‘hot topics’ list, but why do they present a risk and what can be done about it?

First introduced in the early 1990s, Li-ion batteries are a type of rechargeable battery used in a range of consumer electronic products such as laptops, phones and power tools, as well as EVs, E-bikes and E-scooters.

Li-ion batteries offer many advantages, including lighter weight, ability to hold an increased level of charge and ability to hold charge for longer than other rechargeable batteries. They are not inherently unsafe, however they can pose a risk if damaged or managed incorrectly during manufacture, installation, charging, transportation or disposal.

The risk arises because Li-ion batteries use flammable liquid electrolytes to transport positively charged ions between the battery terminals.  Exposure to high heat (either externally, as a result of overcharging or short circuit due to damage) can cause a chemical reaction in the battery resulting in a process called thermal runaway.  This is a phenomenon in which the battery enters an uncontrollable self-heating state reaching temperatures of greater than 300°C, potentially resulting in explosion and release of toxic gas.

As well as burning quickly and very hot, Li-ion battery fires are difficult to extinguish. Because of the chemical nature of the fire standard methods do not work and the primary way to extinguish a lithium battery fire is to flood it or submerge it in water for many hours or, in some cases, days. Whilst this might seem like an easy option on a vessel, sea water is corrosive and can compound the problem. Other forms of extinguishment used for chemical fires can work but, for example, a fire blanket can be difficult to apply given the speed and intensity of fire. The fire service is still learning how to manage Li-ion battery fires and understanding of the risk, guidelines and good practice are still developing.

Whilst the most significant losses have involved car carriers, the number of fires involving E-scooters, E-bikes and other Li-ion powered devices has increased. A Freedom of Information request by Zurich showed that E-bikes and E-scooters were responsible for 167 fires in the UK in 2022, a 250% increase from 2020.

Whilst Li-ion batteries are becoming more regulated, particularly in relation to transportation (for example a ban on power banks being stowed in the holds of planes and a ban on electric scooters on the London underground systems, along with requirements for identification of batteries in carriage) the feeling is we are still on a learning curve in relation to the management of devices containing Li-ion batteries.

The general advice to consumers is to keep devices dry, avoid storing them at extreme temperatures and avoid charging them overnight. Also, products should only be purchased from reputable retailers and should display a valid UKCA or CE mark. They should not be used if the battery appears to be damaged. For retailers, consideration must be given to the quantity of devices kept together, and the conditions in which they are stored.

Managing the risk presented by EVs being transported or stored in high numbers is potentially a much more complex matter, however, detailed fire risk assessment should be undertaken and documented, and a formal emergency response procedure reflecting the risks specific to the environment in which the batteries are contained is key.

In the longer term, there may be a potential alternative that mitigates many of these risks in the shape of solid-state Li-ion batteries. As the name suggests, a solid-state battery would replace the flammable liquid electrolyte with a solid electrolyte that is more stable and can withstand more extreme temperatures. There are also other potential benefits of solid-state batteries in faster and longer charge, greater efficiency and the ability to hold more power for the same weight.

Car manufacturers are leading the way in this development, and they may be in a position to launch commercially available batteries within the next 4 – 5 years. Ultimately, it’s reasonable to expect that solid-state batteries could be used in e-bikes as well as larger commercial and transport vehicles.

In the meantime, careful and detailed management is essential to mitigate the risks of the existing design.