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Li-ion Batteries: Friend Or Foe?

The story and science behind the tech industries' favorite batteries

16Sep

If smart devices were humans, their technical features would be a brain, whereas batteries would be a heart - a powerful accumulator that keeps it all going. The importance of reliable batteries is paramount, as smartphones, transport, computers, and other technologies are useless if they can't last long enough.

At the moment, most major technology producers use Lithium-ion batteries - long lasting enough to support new features, but there have been some question marks over their safety. There have been incidents, where Li-ions exploded, caught fire, injured people, and even brought a plane down (UPS Airlines Flight 6 crash, 2010). Being concerned with safety, the Federal Aviation Association (FAA) questioned the use of Li-ions on board. So when Samsung's new tablets Note-7 started exploding during charging, the FAA issued a warning, encouraging users to not operate Note-7s during flights.

So what is going wrong with some Lithium batteries, and why can’t companies sacrifice it for the sake of safety?

Lithium-ion batteries consist of two electrodes which are separated by an electrolyte, and the latter is a solution for lithium salts and organic solvents. When the battery is charged, Li-ions are driven into a carbon anode - the process that provides power to the battery. Once discharged, ions flow back and create a balance between electrons in a circuit that powers a device. In well-made electronics, safety measures are used to provide a stable performance, but these are not always enough. Li- ion batteries are extremely sensitive when exposed to external environments. Manufacturers try ensuring these batteries exist in safe conditions and minimize potential hazards using a 'hazard control' scheme, which includes a reduction of sensitivity, reaction, and breaking a reaction chain.

However, when batteries are faulty, there is a danger when they are quickly discharged or overcharged - both can be a recipe for a potential explosion. The overheat can create air bubbles inside the battery, and it can catch fire and explode. Likewise, when over-discharged, batteries can still be flammable because Li-ions don't shut off when the power is too low. In the case with Samsung, an investigation of the problem is still ongoing, but we know that devices caught fire when they were charging. The reason why tech companies continue taking such risk is no real alternative to the industry's favorite power source.

Li-ion batteries are everywhere - phones, laptops, electric cars, and even e-cigarettes. Alternatives may provide increased safety, although would be nowhere near as powerful and cheap, meaning technology would need to take a big step back, sacrificing features that demand increased energy. Li-ions require low maintenance, they don't have a 'charging memory' (no need to fully charge and discharge to keep them fresh), and their density capacity is currently the highest.

According to Professor Clare Grey, from the University of Cambridge, Chemistry department, the closest rival in the sector is nickel-cadmium batteries, but they require multiple cells and provide less power: 'There are cathode materials out there already, such as LiFePO4 which are safer and less prone to O2 loss,' but again, consumers would have to accept a lower energy density with this type. If there is no chance to replace Li-ions, can battery makers make them safer?

Yes, and tech businesses are already looking for relevant providers. One of the ways to make Li-ions safer is to replace flammable liquid electrolytes, so they are more stable in various environments - the approach is called 'solid-state'. Whilst still having Lithium as a core, these batteries have greater energy density and are more compact in size. Dyson has recently acquired Sakti3, a solid-state battery company, and Bosch has recently bought Seeo, a developer of a polymer solid-state batteries, orientated for electric vehicles and power grids.

Another innovation may also come in the form of Lithium-air batteries, with automotive companies like BMW and Toyota already investing in their research and development. These would also provide more energy, and are a goldmine for electric vehicles which have suffered from several documented battery failures. Considering companies are not giving up on Li-ions, the industry of Lithium-iron phosphate will continue growing, supported by high demand. According to Markets and Research report, the analysts forecast the global Lithium iron phosphate battery market to grow at a CAGR (compound annual growth rate) 20.5% in the period of 2016-2020, helped in part by the construction of Tesla’s Gigafactory which is predicted to create more li-ion batteries in one year than the entire world created in 2013.  

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