Vital safety considerations of battery storage in electric vehicles

Vital safety considerations of battery storage in electric vehicles

The world of motor vehicles is rapidly changing, as technologies continue to advance and research of safer, more efficient alternatives progresses. The number of electric vehicles on the road is increasing at significant rates, and this trend will continue to grow as traditional petrol-based vehicles are phased out in the run up to the ban of petrol and diesel cars that starts to roll-out globally from 2030. 

Battery storage in electric vehicles is a major topic of discussion in the current climate; researchers are constantly discovering new ways of improving the efficiency of electric batteries. From vehicle performance to environmental implications, there are many aspects to consider when developing an electric vehicle battery (EVB). 

For many years, lithium-ion batteries were the focus of manufacturers, however there has been a shift towards the use of hydrogen fuel cells to power electric vehicles instead. There are important differences between the two, with hydrogen fuel cells having a much greater weight ratio when compared to lithium-ion batteries (further details on the differences between lithium-ion batteries and hydrogen fuel cells can be found here). 

While electric vehicles help cut down on emissions, and begin to reduce our dependence on fossil fuels, it’s worth noting that there are some battery storage safety implications of this relatively new technology, specifically in relation to the battery storage itself. Here we’ll discuss the vital safety considerations of battery storage in electric vehicles.

 

Combustion

The first battery storage safety consideration for EVBs is the risk of combustion, particularly in lithium-ion batteries. It’s important to firstly recognise that problems are highly unlikely to occur if the vehicle is being looked after responsibly. Using correct voltages to charge the batteries, for a suitable amount of time will help mitigate the probability of any hazards occurring. 

When overcharging the batteries, or charging them too fast, the batteries are at risk of short-circuiting which can lead to fires and even explosions. Short-circuiting essentially causes the cell to overheat, which can be exacerbated by a lithium-ion battery’s flammable electrolyte liquid. This electrolyte liquid can be a further complication to most issues that occur within an EVB, due to issues with the batteries often involving some degree of overheating and therefore increasing the risk of electrolyte liquid being set alight. 

Hydrogen fuel cells unfortunately share the risk of combustion as well. Hydrogen is a highly flammable gas so it is of no surprise that damage to these batteries can cause serious problems. Unforeseen damage to a vehicle, for example in an accident, may lead to the EVB becoming crushed or penetrated. If this occurs, the risk of liquid or gas from within the fuel cells leaking out of the storage casing increases. Any form of ignition from a spark for example, could then lead to the liquid combusting. The good news however, is that modern electric vehicles and the batteries within them are tested vigorously and technology has meant that the risk of any fire hazards is minimal.

Elmelin’s work using mica as an insulation material can help mitigate these safety concerns. Mica has natural mineral properties which mean it can function as excellent insulation, whilst also being highly durable and adaptable to many different products and scenarios. In multiple forms, from pure to microporous, mica will offer solutions to car battery overheating. The storage of these batteries can be made safer using mica insulation, helping mitigate the risk of fires igniting within EVBs. Mica is a key component of heat shields which can be implemented in electric vehicles in order to reduce the spread of heat and possibly fire.

 

Electrolyte Liquid

An EVB will contain a form of electrolyte liquid, which allows for electrical charges to pass through the battery and into the vehicle. As mentioned above, these liquids are flammable and can become a fire hazard within an electric vehicle. However, there are more safety concerns related specifically to this liquid. Due to the nature of liquid, there will always be a risk of leakage. When this occurs within the EVB, specifically lithium-ion batteries, there is a chance for the formation of hydrofluoric acid.

Hydrofluoric acid can be produced by combustion or interaction with air moisture or water, within the vehicle. Once this occurs, major health and safety implications arise. Hydrofluoric acid is highly corrosive and toxic, so having it within the EVB and/or vehicle becomes dangerous. In regards to the corrosivity, this can lead to physical damage to the vehicle, wherever it is located. If produced within the EVB, there is a possibility for degradation to the battery casing, which could lead to holes forming and leakage to other parts of the vehicle.

Furthermore, due to these corrosive characteristics and toxicity, serious risk to health arises if someone were to be in contact with hydrofluoric acid. It’s known to cause severe chemical burns to the skin and permanent damage to eyes, and urgent treatment is required to avoid longer-lasting effects on the body. If an electric vehicle suffers from the leakage of electrolyte fluid and formation of hydrofluoric acid, it may prompt a driver or mechanic to take a look at the engine and internal components. This is where the risk to safety becomes concerning, where the acid may have spread to these parts of the vehicle and lead to somebody touching it with their hands. Additionally, many electrolyte liquids contain either sulphuric acid or potassium hydroxide, which similarly to hydrofluoric acid, are highly corrosive. All 3 of these chemicals are also poisonous to humans when swallowed. 

While all of this may sound concerning, the risk is extremely low, and the safety measurements that are in place with vehicle production are very strict. The likelihood of coming into contact with any dangerous chemicals within or surrounding a battery only becomes slightly higher when removing the battery for disposal, which will almost always be carried out by professionals. If you are concerned about touching vehicle components yourself, such as under the hood of the car, the safest thing to do is wear sturdy gloves designed to protect against hazardous or acidic chemicals, and wear eye protection.

 

Thermal Runaway

Another battery storage safety consideration for EVBs is the occurrence of thermal runaway. This is a process where heat continues to build within a vehicle due to the formation of a negative feedback loop. The reaction is essentially when temperature changes within the battery cause it to expand and contract, which then leads to an unbalanced flow of electricity, eventually resulting in rapid temperature rises. These rapid increases in temperature can be extremely dangerous to the driver and passengers inside.

Elmelin offer compression pads to help slow down thermal propagation which in turn reduces the risk of accidents and fatalities. Elmelin’s compression pads  maintain thermal and electrical connections, whilst also effectively managing battery expansion when they become overcharged or exposed to extreme temperatures. Find out more about the work Elmelin does in reducing the risk of thermal runaway here.

 

Conclusion

As the number of electric vehicles on the road increases, so will the development of safer and more efficient battery storage technology. The risks discussed in this article, while serious, are also very rare. This is due to the rigorous testing and in-depth research that takes place to keep them as commercially viable as possible. Moreover, it should be recognised that there are also significant dangers associated with petrol-based vehicle engines. As with any piece of machinery, when handling any components of an electric vehicle, you should always take care in wearing gloves and washing your hands after. This can help avoid contact with any potentially harmful chemicals that may have leaked, no matter how rare this can be. 

Elmelin are working to help reach the net zero target and improve both the efficiency and safety of battery technology in electric vehicles through innovative mica-based solutions. If you’d like to find out more, get in touch