Engineers Contemplate Lithium-ion Safety

 

By Quintus Potgieter

Lithium-ion batteries power our world more than we realize. They’re in our cell phones, our laptops, pacemakers, watches, e-cigarettes, and cars. More recently, they have been built into energy storage units that power entire houses and businesses and those pesky “hoverboards” the kids are driving. There are even lithium-ion battery systems inside aircraft and NASA astronaut spacesuits. The batteries play a big part in the future of global clean, renewable energy due to their integrability with power grids around the world. A report by Goldman Sachs called lithium “the new gasoline”, indicating that the electric vehicle boom the world is about to see, is going to drive demand for lithium all the way up. So, a healthy market for a healthy battery, right? Not exactly. On the odd occasion, lithium-ion batteries can be a fire hazard.

Firstly, those aforementioned “hoverboards”. According to the United States’ Consumer Product Safety Commission, as of July 2016, the lithium-ion-powered hoverboards have caused up to $2 million in property damage as a result of 60 different fires. The CPSC’ Chairman Elliot Kaye said: “After months of excellent, round-the-clock work by our engineers, investigators and compliance officers, CPSC has secured the recall of more than a half-million hoverboards by 10 different companies.” The chairman further warned companies designing the hoverboards that more needed to be done in the implementation of the electrical systems and the battery packs the products use. The engineers working for the CPSC tested the hoverboards to try and explain why they explode the way they do. What they found is that the multicell battery pack - that houses 20 lithium ion cells -  are a fire hazard because if one catches fire, they all do. One explanation is that the heat threshold of the lithium batteries inside is surpassed and causes a fire due to cheaply made lithium-ion components.

Earlier in 2016, a photo of an exploded lithium-ion household energy storage battery made its round on Australian social media. The exploded battery raised questions in engineering circles about the safety and market-readiness of lithium-ion batteries. The Clean Energy Council of Australia then underlined the problem with current home energy systems being sold and installed in consumers’ homes. It was revealed that battery storage installers with zero education about lithium-ion batteries could install the energy storage systems inside households. As a result, the council released installation guidelines for grid-connected energy systems that would encourage safety measures when lithium-ion technologies were installed.

The Dean of Engineering at the Engineering Institute of Technology, Steve Mackay, spoke about the general training that installers should get when installing energy storage solutions. He said: “With training not only do you need to have basic electrical theory, you need to look at safe working with photovoltaic cells, batteries, connecting to the grid and finally the financial and economic aspects of connecting to the grid.”

The cause of the exploded energy storage unit battery is a widely known issue with lithium-ion batteries called thermal runaway. Does this mean that the energy storage units released by companies like Tesla, Daimler AG etcetera are dangerous to use? Not by a long mile. Thermal runaway is a rare occurrence in lithium-ion battery technology. It is the cheaply manufactured energy storage units bought for a bargain that might be exploding on you. The temperature threshold for lithium-ion batteries is 250 degrees celsius (482 Fahrenheit). However, there have been some cases where it occurs. What happens is, a battery gets overheated to the point where the heat reaches temperatures it can no longer contain. Once the battery gets hotter at a faster pace than it can produce and absorb heat, a fire or explosion is sometimes likely.

To further combat thermal runaway, researchers at Stanford developed a battery sensitive to overheating issues. Using an engineered polymer that would expand with heightened temperatures, the battery would shut down once the heat reached 160 degrees (320 Fahrenheit). It is clear that engineers will continue to problem solve when it comes to lithium-ion technologies so that the technology can truly grow to be the “next gasoline”.

Engineers in companies that produce premium lithium-ion batteries use nickel manganese cobalt technology. The technology is used for LG Chem and Tesla energy storage units - and most recently electric vehicles -  purely for its ability to withstand temperatures of up to 210 degrees celsius (410 Fahrenheit) before thermal runaway occurs. The nickel manganese cobalt technology is one of the most cost-effective lithium technologies, making it the best suited for energy storage applications.

According to Bloomberg's New Energy Finance New Energy Outlook Report of 2016, the energy storage market will be valued at $250 billion by 2040. A lot of that energy storage will be thanks to lithium-ion batteries due to the cost effectiveness of Li-on technology. Technavio estimates that Li-on battery costs have dropped at 23% per year since 2010, and they are bound to become cheaper. In a world desperate for clean, renewable energy, it seems that lithium is in big demand and is here to stay.