The solar revolution is in full swing, and for good reason. Making free energy while the sun shines is good for you and good for the planet, and a home battery system seems like the next logical step.
I can’t argue with that, but I’m hitting pause on a battery system for now. Here’s why.
The problem with current home battery systems
Lithium-ion batteries in the home
Home battery systems currently use a similar lithium-ion battery technology as a smartphone or laptop. There are different types of lithium-ion batteries, and the current gold standard for home storage and electric vehicles is lithium iron phosphate (LiFePO4), also known as lithium ferrophosphate or LFP batteries.
Lithium-ion technology has some big benefits, starting with energy density. This allows the battery to take up less space while still providing a good amount of charge for energy-intensive tasks. Lithium-ion battery lifespan has improved over the years, anywhere from a few thousand to 15,000 cycles, with a five- to ten-year warranty on home battery systems being the norm. This technology has transformed our lives, though it’s not without some downsides.
Perhaps the biggest concern that many of us have is the threat of thermal runaway—a phenomenon that occurs as a result of an uncontrollable chemical reaction. This generates heat, which can eventually lead to fire and explosion. Though LFP batteries are considered safe, the risk of thermal runaway is still present. It is most commonly associated with high temperatures, physical damage, and overcharging.
Though high temperatures can spell danger, low temperatures are also bad news for lithium-ion batteries. Though batteries can be discharged safely at temperatures of about -4ºF (-20ºC) and above, charging them at 0ºC or lower can permanently reduce battery capacity. Thermal management is an important part of modern battery systems as a result.
One aspect of lithium-ion batteries that you might not consider is that the availability of raw materials is limited to a few countries and difficult to mine, with prices ever-increasing as demand grows. With battery demand increasing twenty-fold since 2010, even established supply chains are under pressure. This is before we consider the environmental damage and human rights concerns. The cost of lithium-ion batteries is also affected by the cost of copper, a pricey commodity which is used in their production.
Batteries are an expensive investment; they need to last a long time. They also need to be safe, especially if they’re going to live under the same roof as you. I’m not trying to throw shade at your lithium-ion home battery, but as someone who is looking to make an investment, I’ve got my eye on something else.
Sodium-ion batteries look promising
A better alternative to lithium-ion batteries at home
Sodium-ion is a promising battery technology that has some potentially big benefits for home users. Chief among these is stability, with sodium-ion cells designed to eliminate the risk of thermal runaway. The batteries are also capable of operating in a far greater range of temperatures, and can even survive in freezing cold conditions (-40ºC/F).
These batteries are already on the market, with systems like UNIGRID’s Na+Casa home battery system offering a lifespan of 25 years, matching that of a modern home solar installation. Then there are the benefits of building a material from sodium, a raw material that is abundant and relatively easily extracted from seawater.
Sodium-ion batteries use a cheap raw material that’s available anywhere on earth. In theory, this should make them cheaper to manufacture, though supply chains and demand can’t yet match the lithium-ion industry. The technology is also new, and will likely demand a premium for a while yet. Companies like UNIGRID have yet to publicly disclose the cost, which should raise eyebrows. Most inverters are built to lithium-ion battery spec, so price bumps could be seen in other areas too.
These batteries are far from perfect, but they are surprisingly well-suited to static installations. Sodium-ion batteries are roughly 30% less dense in terms of energy storage compared to LFP batteries, so they take up about a third more room for a comparable store of energy (while also being much heavier). For EVs and smartphones, this could be a deal-breaker.
But for homes, it’s much less of an issue. As someone who will put a battery in the garage underneath my home, size is the least of my concerns. Safety and lifespan are much more important to me, so I’d happily trade density for peace of mind and value for money. It’s also likely that the technology will improve further still as time goes on, as was the case with lithium-ion batteries, so this could just be the start.
Pick the battery that’s right for you
Lithium-ion systems are readily available
I live in a city, where power outages are thankfully rare. This gives me the luxury of being able to wait to install a battery system, though I’ll pay for it in monthly power bills. Solar can help me reduce outgoings, and a shift in habits can go a long way.
I don’t have an EV, and I don’t need to drive a lot. I work from home and sometimes go two months before needing to fill up the tank. I love the idea of a battery system for true redundancy, but it’s not a must-have right now.
If you live rural, where infrastructure isn’t as robust and power outages are a real concern, you might look at the offerings in a different light. Lithium systems are solid choices that have seen widespread adoption for a reason. They’re available everywhere, and if you’re lucky to have a rebate scheme available to you, then that can bring the cost down too.
Lithium batteries are also highly recyclable, so “spent” lithium will see new life in another battery if you recycle it properly (and that goes for all of your gadgets).
If you love the idea of a home battery system but are always moving house or forced to rent, you might be interested in a mesh battery system.
- Brand
-
Pila Energy
- Capacity
-
1.6kWh
Pila’s mesh home battery creates a mesh battery network by sending electricity back into the wall outlet. Its slim design supports the product being placed throughout the home as part of an everyday energy management system.
