Batteries for storing solar energy have recently gained a surge in popularity. With this hype, it is common for misleading or confusing information to become widespread. If batteries can help keep the lights on during an outage and save you money during times when the grid charges higher rates, they are an important investment, and navigating through the nuances of new technologies with a variety of prices and features can be overwhelming.
Cobalt is used as a cathode in lithium-ion batteries. To store energy, all batteries need a cathode, anode, and an electrolyte. Lithium-ion batteries, like the ones in your smartphone, laptop, or most electric vehicle, use lithium as their electrolyte and usually graphite or silicon as an anode. The choice of cathode makes a big difference in the characteristics of the battery, as well as its environmental impact. Many lithium-ion batteries use cobalt as a component because it allows for a high energy density. Storing a lot of energy in a small space is important for a battery, especially for uses in cell phones and other small consumer electronics. Cobalt is also useful for releasing a large amount of electricity at once, like for accelerating a Tesla 0-60 in 2.5 seconds.
Anything that is installed in your home needs to come with a strong guarantee that it will keep you and your family safe. Lithium-ion batteries are generally safe, especially when compared to alternatives like lead acid batteries or diesel generators traditionally used during power outages. However, the chemistry of different lithium-ion batteries can cause some to be safer than others.
Home batteries have been around for quite some time, but what really created a surge in popularity was the release of the Tesla Powerwall back in 2015. Tesla for sure knows how to create new needs and home storage is no exception. Quickly after the launch of the Powerwall 1, other big names such as LG released their own home batteries.
If the synergies between the car battery and home battery markets seemed to make sense to most, the fact that a car does not operate like a home seemed eclipsed. Indeed, when a car needs strong accelerations, a home’s appliances thrive on steady uniform power.
Although most batteries live under the “Lithium-ion technology” appellation, other metals and chemicals are used to complete their chemistry. Most home batteries on the market use one of the following two chemistries: Lithium Nickel Manganese Cobalt Oxide (NMC) and Lithium Ferro Phosphate (LFP). While LFP batteries tend to be slightly larger in size, they have major safety advantages over NMC.
The most important factor in battery safety is the risk of thermal runaway. This is when batteries short-circuit and heat up so fast that they catch fire. Batteries with cobalt in them risk thermal runaway while LFP batteries’ chemistry make this virtually impossible under normal conditions.
After a series of fire catching electric vehicles, massive recalls for batteries posing fire risk and a million dollar lawsuits between GM Motors and LG that made the news headline last fall, the safety risk associated with NMC batteries and Cobalt is now well known.
Probably one of the reasons why Tesla announced last October that they’ll be switching its normal range vehicles (entry-level Tesla Model 3 and Tesla Model Y versions) to cobalt-free LFP batteries. Early this year, during the Q&A session related to the Q4 2021 financial report, Tesla CEO Elon Musk said that he expects a transition of all stationary energy storage products to LFP battery chemistry.
Avoidance of thermal runaway is not the only safety feature of iron phosphate batteries. LFP batteries are also landfill safe (some are even 100% recyclable), contain no toxic elements, do not require cooling or ventilation, and can operate safely in a wider temperature range than NMC batteries. Battery systems degrade naturally over time, but a system that retains its capacity longer and delivers you more electricity throughout its lifetime is more valuable. LFP batteries are slightly more expensive up front, but are more price competitive once their slower degradation is taken into account.
Last but not least, the mining of cobalt raises serious ethical issues: last year 70% of the cobalt mined around the world came from the Democratic Republic of the Congo. Political instability and corrupt governments have led to the mistreatment of the country’s natural resources and ecological abundance. Cobalt exposure is highly toxic to humans, but many miners in the Congo use only hand tools and have little, if any, safety equipment. Worst, there have been many reports of child labor used to mine Cobalt.
When it comes to home batteries, LFP batteries have proven to be safe, durable, environmentally-friendly and are an ethical choice. That’s why years ago Brighten decided to only install LFP batteries.