It seems like a month does not go by, without hearing news reports about battery explosions in e-cigs, headphones, smartphones or other electronic gadgets. Granted that stories about explosions are considered newsworthy, but has the statistical rate of battery failures actually gone up in the last few years? Has the impact of battery failures increased and if so, why? And, I am of course talking about Lithium ion batteries, the go-to battery chemistry in rechargeable electronic devices owing to their high energy density. I am certain you do not want to be carrying around a brick for a smartphone.
Has the Statistical Rate of Lithium Ion Battery Failures Actually Increased Recently?
The battery marketplace has evolved significantly in the last couple of decades. Battery suppliers have been under pressure to move to higher energy density, sometimes with thinner separators. This lowers the tolerance for manufacturing defects even more. With the emergence of Internet of Things (IOT) and M2M (Machine to Machine) applications, many smaller device manufacturers that do not have core battery expertise have started to buy and use COTS (commercial off the shelf) lithium-ion batteries. Safely using lithium-ion batteries today requires insight into the cradle to grave battery lifecycle, including manufacturing, transportation, warehousing, device integration, use, and recycling. Not having this knowledge puts these companies and consumers of their products at somewhat elevated risk.
Market share has also started to move from large Japanese companies that have traditionally dominated lithium-ion battery manufacturing, to competitors in China, South Korea and other Asian countries. Many smaller players, some with questionable manufacturing quality, have entered the fray.
Overall, even though Lithium-ion market trends may appear to be moving towards higher field failure rates, statistically these are still fairly low. Of the billions of lithium-ion batteries produced annually worldwide, the rate of field failures is roughly between 1 and 10 ppm. However, the impact of these energetic failures can be so severe as to be life changing.
So that brings us to the next question.
Has the Impact of Lithium Ion Battery Failures Increased Recently?
I would answer yes, and market conditions are mostly to blame. Each of us owns at least 10 gadgets that have a lithium ion battery in it. With the emergence of IOT (Internet of Things), these devices have been creeping closer to the human body, creating an elevated impact if catastrophic failure does occur. We carry around our cell phones all day, wear our smartwatches, and bring E-cigs in contact with the face. While high energy and power densities are great for our smartphones and smartphones, this also means the impact in case of thermal runaway is higher.
Explosions and fires caused by lithium-ion batteries have resulted in billions of dollars’ worth of damage, and even deaths. A 2017 report from CPSC reports 3 deaths from battery fires in hoverboard applications. Violent explosions from E-cig failures have been reported to cause loss of body parts, disfigurement and third-degree burns . The first E-cig related death was reported this month in 2018 .
The economic impact of battery failures for the companies involved has also been massive. Samsung recalled 2.5 million Galaxy Note 7 phones in 2016 eventually scrapping the entire product line, with a total loss of 5 billion dollars . Nokia recalled 46 million cell phone batteries in 2007 due a manufacturing defect, that created a risk of explosion. Sony’s 2006 battery failures stemming from a manufacturing defect, caused it to recall 10 million laptop batteries. In a majority of these cases, the statistical rate of field failures is still below 10 ppm.
What can you do as a consumer to be proactive about Lithium-ion battery safety? Remember that the battery protection system comprises of circuitry on the battery as well as the charger and is optimized for the specific Li ion chemistry. Any time you use a cheap charger, or buy cells of questionable quality, that protection system is comprised, and puts you at elevated risk. Always use the charger provided with your electronic device, and do not buy cells on the internet.
How can you be proactive about Lithium-ion battery safety if you are a host device assembler? Have a supplier qualification program in place. Conduct CT scans and cell teardowns on a handful of cells to assess manufacturing quality. Review the adequacy of your battery protection system. Make it hard for a consumer to use an authorized charger by using a custom connector.