An L-shaped orange mounting structure with two white reservoirs on top, a set of pumps on the outer bottom edges, and a membrane cell bolted together in the center. The parts are connected by a series of transparent tubes.

Open Source Residential Energy Storage

Battery news typically covers the latest, greatest laboratory or industry breakthroughs to push modern devices further and faster. Could you build your own flow battery stationary storage for home-built solar and wind rigs though?

Based on the concept of appropriate technology, the system from the Flow Battery Research Collective will be easy to construct, easy to maintain, and safe to operate in a residential environment. Current experiments are focusing on Zn/I chemistry, but other aqueous chemistries could be used in the future. Instead of an ion exchange membrane, the battery uses readily attainable photo paper and is already showing similar order of magnitude performance to lab-developed cells.

Any components that aren’t off-the-shelf have been designed in FreeCAD. While they can be 3D printed, the researchers have found traditional milling yields better results which isn’t too surprising when you need something water-tight. More work is needed, but it is promising work toward a practical, DIY-able energy storage solution.

If you’re looking to build your own open source wind turbine or solar cells to charge up a home battery system, then we’ve got you covered. You can also break the chains of the power grid with off-the-shelf parts.

A vanadium based flow battery made with 3D printed parts

A Vanadium Redox Flow Battery You Can Build

Vanadium flow batteries are an interesting project, with the materials easily obtainable by the DIY hacker. To that effect [Cayrex2] over on YouTube presents their take on a small, self-contained flow battery created with off the shelf parts and a few 3D prints. The video (embedded below) is part 5 of the series, detailing the final construction, charging and discharging processes. The first four parts of the series are part 1, part 2, part 3, and part 4.

The concept of a flow battery is this: rather than storing energy as a chemical change on the electrodes of a cell or in some localised chemical change in an electrolyte layer, flow batteries store energy due to the chemical changediagram of a vanadium flow battery of a pair of electrolytes. These are held externally to the cell and connected with a pair of pumps. The capacity of a flow battery depends not upon the electrodes but instead the volume and concentration of the electrolyte, which means, for stationary installations, to increase storage, you need a bigger pair of tanks. There are even 4 MWh containerised flow batteries installed in various locations where the storage of renewable-derived energy needs a buffer to smooth out the power flow. The neat thing about vanadium flow batteries is centred around the versatility of vanadium itself. It can exist in four stable oxidation states so that a flow battery can utilise it for both sides of the reaction cell.

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Weird Energy Storage Solutions Could Help The Grid Go Renewable

We’re all familiar with batteries. Whether we’re talking about disposable AAs in the TV remote, or giant facilities full of rechargeable cells to store power for the grid, they’re a part of our daily lives and well understood.

However, new technologies for storing energy are on the horizon for grid storage purposes, and they’re very different from the regular batteries we’re used to. These technologies are key to making the most out of renewable energy sources like solar and wind power that aren’t available all the time. Let’s take a look at some of these ideas, and how they radically change what we think of as a “battery.”

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Storing Energy In Liquid Form

Researchers in Singapore have created a new kind of redox flow battery with an energy density around ten times higher than conventional redox flow batteries. Never heard of a redox flow battery? These rechargeable batteries have more in common with fuel cells than conventional batteries. They use two circulating liquids separated by a membrane as an electrolyte. Each liquid has its own tank, and you can recharge it by pumping in fresh electrolyte. The redox in the name is short for reduction-oxidation and refers to the process that stores energy in the two liquids. You can learn more about flow batteries in the video from Harvard below.

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