Components

There are many different components involved in solar and battery systems. Here we'll try to list the major ones and how they fit into the system.

Batteries

Needless to say, there is endless variety of battery storage available. Everything from re-purposed used e-bike and EV batteries to commercial off the shelf (COTS) storage solutions. Furthermore, there are all sorts of emerging battery technologies it's hard to keep track of them all, which was the original motivations for this site, because I wanted a way to keep track of developments in battery chemistry, type, form factor, etc. since there is so much investment and innovation going on these days. Those material scientist are ingenious and we've just started to scratch the surface of what can be achieved with batteries.

COTS

There are numerous suppliers of COTS battery storage solutions. While there has always been a nascent Do It Yourself (DIY) contingent and will continue to be for those for whom cost savings, personal knowledge, and experimentation are of primary concern, the field really reached the main stream when Tesla introduced the PowerWall. Now there are many competitors including Generac, Franklin Energy, Enphase, many suppliers of so called "server rack" batteries, and innumerable suppliers from China.

DIY

For the Do It Yourselfer (DIY), the possibilities are literally limitless. With videos on YouTube and ordering parts on the internet anybody can get started working on projects that appeal to their personal interest. 

E-mobility

I got started because I had an old longboard (skateboard) lying around, and I though it would be interesting to get an electric one, but I wasn't willing to pay upwards of $1,500 so I started to learn how to build my own. Then there is the whole e-bike and motor-bike industry. Again, I had a motorcycle with a blown engine (BMW K1200s) that I started thinking of converting to an electric motorcycle because I figured I could do it much cheaper than the $20k for a commercial high performance motorcycle, which I couldn't afford in any case, but I needed it to be highway capable and more performant than then various "city" bikes which can be found for any where from $3k to $15k.

 Stationary Storage

As with mobility, I became interested in stationary storage because the deep cycle AGM batteries on my boat were failing and needed to be replaced, and instead of just replacing them with more lead acid batteries, I figured I could build a battery out of raw LiFePo cells that would offer twice the capacity of the AGMs at half the weight and approximately the same or a little more cost, where as commercial Lithium batteries from BattleBorn and Dakota Lithium were twice or more the cost, and even the discount batteries were about $1K where as I could build one for about $600 all in.

The build was further complicated by the narrowness of where the battery had to go into beneath the steps from the salon leading up to the cockpit. If I bought commercial batteries, I would have to go with much less capacity, but if I built it myself, I could easily get 12 v 280 ah of battery into the space.

Emerging Battery Technology

This is an area that is endlessly fascinating. There are so many companies pursuing so many technologies and chemistries, it's hard to keep track of them all. It's common in the battery world to have a dose of scepticism about any claims made particularly around result made in a lab but are always 3-5 years from large scale commercialization. If I had a dollar for every time I heard about some breakthrough that just needed to be scaled, I'd be a rich person. Nonetheless, it can be worthwhile to keep track of the major chemistries and some of the competitors.

Electrolyte

There are basically two types of batteries. Those that use some sort of electrolyte to separate the anode and cathode and those that use a solid material as the separator (discussed under Solid State below).  These batteries are considered dangerous because the electrolyte is flammable and can result in "thermal runaway" if the battery is punctured or otherwise badly damaged. However, gasoline is also flammable and there is no end of ICE cars that catch fire every year.

Lithium Ion

Lithium is the primary metal used because it so easily shares its electron and is the third lightest element.

Turnerary

This chemistry is the most common and is the basis for the 18650 and 21700 battery cells which are common in everything from power tools to laptops as both cylindrical and pauch cells that power phones and other electronic devices. The energy density of Lithium Ion batteries is somewhere in the range of 200-250 Wh/kg.

MNC - Manganese Nickel Cobalt

LFP (LithiumIronPhosphate)

These batteries are less energy dense than typical Lithium turnerary batteries and so are heavier and bigger for the same capacity, but have the advantage of being non-flammable and various advances are making them more competitive with turnerary batteries every day. These batteries generally range in the 160-200 Wh/kg.

Sodium Ion

These batteries are relatively new to market with BYD and CATL just starting production this year in 2023. The main motivation for sodium is the relatively higher prices of Lithium, although the cost of Lithium which spiked severely recently, it has come down dramatically more recently. Of course, there is no free lunch and while Sodium is cheap and abunday, it is a much larger ion and has lower energy energy density of about 140-160 Wh/kg.

Solid State

Companies

Tesla

Tesla is one of the biggest users of batteries in the world and is aggressively make moves up and down the supply chain the secure their supply. They originally partnered with Panasonic in their first "Gigafactory" in Nevada on 18650 cells, then moved to 21700 cells. They now use pretty much every kind of cells from LFP to their latests 4680 battery with a dry anode technology that they are still in the process of trying to ramp up to support CyberTruck and Tesla Semi. To really deep dive into Tesla you can watch a replay of their Battery Day on YouTube. 

Gotion HiTech

Sakuu

QuantumScape

StoreDot

SilaNano

ProLogium

SolidPower

GangFeng Lithium

BrightVolt

Blue Solutions

Bosch

Toyota

SK Innovations

Johnson Energy Storage

Cymbet Corporation

Nasa

Convergent Aeronautics Solutions SABERs (Solid-State Architecture Batteries for Enhanced Rechargeability and Safety for Electric Aircraft) Project