Different types of batteries have been available over the years. This is a lead-acid battery. (Courtesy photos)
Chris Milner
Battery storage is the fastest growing industry in the United States, with sales expected to exceed $50 billion by 2028. Grid instability, rising costs of electricity, and politics are the driving forces in the rising demand for battery storage. There are a lot of battery storage products out there, but the information to guide the buyers is confusing at best, leaving them wondering what technology is best for them.
Back in the day, the lead-acid battery was all we knew and standard for energy storage. Batteries were composed of lead plates with sulfuric acid inside. While these were effective and could be long lasting (up to 20 years if not cycled deeper than 20%), they were high maintenance. Every week you would have to check the electrolyte (acid) levels and add distilled water, or they would not last longer than a few years. Since they were non-sealed batteries, you also had to vent them to the outside, so deadly sulfur gas doesn’t build up in your home. In the 1970’s, AGM (Absorbed Glass Matt) batteries made their first appearance. It was still a lead-acid battery, which used lead plates and sulfuric acid, except now all the acid was absorbed into the plates. This resulted in a maintenance-free battery, which slowly became more and more popular and are now found in all new cars and trucks. The downside of AGM technology, or any lead acid for that matter, is that when left at a state of discharge for a length of time, the sulfur from the acid sticks to the lead plates causing the battery to lose its maximum capacity. To repair a sulfated battery, de-sulfating formally known as “equalization” would have to be done, which helps restore the batteries’ capacity but does affect battery life. All this added maintenance to what was supposed to be a maintenance-free battery. In general, AGM batteries last about six to eight years if not cycled deeper than 50%.
AGM battery
In the 1990’s, lithium-ion batteries began to hit the storage market, but due to instability issues, by 1997 they were replaced with lithium iron phosphate (LiFePO4) batteries, which were more stable and are the battery found in most of the energy storage systems today. The lithium battery technology brought a whole new set of benefits to the storage industry; batteries were now available that lasted ten years or more, could be cycled deeper than any other battery technology without damage or sulfating, and were truly maintenance-free, but this great technology comes at a cost. The price of lithium-based batteries is more than double the cost of any other battery technology available, and the process to manufacture the lithium batteries requires dangerous mining of rare earth minerals (cobalt) which have a great impact on the environment, workers’ health, and safety. While lithium iron phosphate batteries are safer, they are still not without risk either, if the charging circuit (called the BMS or battery management system) were to fail, they can overheat and catch fire. As a further impact, lithium batteries are also only 35% recyclable.
Lithium battery
Carbon batteries are the latest to hit the U.S. market. While they were invented back in the 1950’s, they are just starting to hit the residential market now. Here’s what makes carbon the best replacement for lithium in the storage industry. They have the same cycles as most comparable lithium technologies, giving them the same 10- to 20-year life span. They can be discharged 90% without damage just like the lithium counterparts, but there is no dangerous mining and carbon batteries are 100% recyclable. They also cost nearly the same as a standard AGM battery; the only downside is they weigh more so can’t be an alternative for electric cars.
How did they do it? Quite simply actually, the issue with the AGM battery was sulfur sticking to the lead plates in a state of discharge, so why not just replace the plates with something better than lead? Well, that is what they did. Carbon, which is one of the most abundant minerals on earth (found in stone and can also be man-made), is also a good conductor of electricity when in its mineral form, but sulfur can’t stick to it! So, by infusing carbon into the plates of the battery (there is still a small amount of lead) they are able to make an AGM type of battery that doesn’t sulfide up, can be cycled deeply without damage, will last just as long as its lithium counterparts without the expense or hazards, and, because carbon is a natural and stable mineral, it’s easy to recycle.
Univix Carbon Battery
In summary, you can still buy standard lead-acid batteries at a lower price than most technologies out there if you don’t mind the weekly maintenance or venting requirements, but carbon batteries have opened a whole new door to the consumer, offering all the benefits of the previous industry-leading battery without all the added cost, dangers, or environmental impacts. Consumers now have a better and more affordable choice than ever before.
Chris Milner is the CEO of Univix Power Solutions. Chris has a degree in electrical engineering and has over 30 years’ experience in the on- and off- grid solar industry working with and owning an installation company. In 2018, Chris co-founded Univix in Laconia, NH with the goal of manufacturing energy storage solutions that were environmentally-friendly, powerful, easy to install and affordable for everyone.
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