Something you probably didn’t know about EVs
Posted on 24th November 2021
Electric vehicles (EVs) are becoming more popular as a sustainable transport option, but there’s something you might not know.
Manufacturers are releasing more affordable EV models and the government is pushing ahead with change through legislation to end sales of fossil fuelled vehicles from 2030.
The EV battery problem
Although the system is less than perfect, our traditional carbon-emitting vehicles use lead-acid batteries which are widely collected and recycled. However, EV lithium-ion batteries are another matter.
The raw materials for EV batteries often include cobalt, nickel, and manganese. Mining these materials has an environmental impact and elements released into the atmosphere during the process can contaminate soil. The batteries themselves are more difficult to recycle creating a disposal problem at the end of their life.
Despite the drive to increase EV use, lithium-ion batteries are also in short supply. Although worldwide production capacity is expected to increase massively it still won’t be enough to meet the expected demand.
New recycling methods are being explored, but the short-term solution will be to significantly increase the life of the batteries, currently expected to be around 11 years.
Longer lasting batteries
Designers are looking at regenerative braking to slow battery ageing by reducing the build-up of metallic lithium on the battery’s anodes. This problem is worsened by long charging periods.
An EV can recover energy when it’s slowing down using its electric motor as a generator. This energy can be stored in the battery, increasing the vehicle’s range and efficiency between charges. Recharging the battery with small amounts of energy each time the vehicle brakes will reduce the length of the charging period, helping to cut the build-up of metallic lithium. As a safety measure, resistors are needed to remove excess energy from the system if the battery is already fully charged, preventing overcharging that would damage the system.
Both long and short-term solutions to the EV battery problem will be needed before EVs can fully deliver their sustainable transport promise. We will be interested to see what happens next.
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