Iron-air Battery, Shape Memory Alloys for Cooling and Self Healing Phone Screens

July 28

This week we will examine a new battery that will help to bring storage to grids that use significant amounts of renewable energy. We also discover a Shape Memory Alloy that will remove the need for the use of refrigerant gases in air conditioning and refrigeration whilst reducing operational costs by 30 to 40%. We also look at a possible way for cracked phone screens to heal themselves and an autonomous excavator for building and construction sites. Finally we update a story from last week. The world is moving quickly when significant developments are released week after week in some fields.

Iron-air Battery

Form Energy, a startup from Somerville, Massachusetts has developed an iron-air battery for grid scale energy storage. The battery can deliver electricity for 100 hours before recharging and costs 1/10th of a comparable lithium-ion battery. Additionally a lithium-ion battery can only supply grid scale power for 2 to 4 hours.

Designed to store energy from solar and wind farms the battery is reliable, cheap and uses abundant materials. Their first commercial project is in Minnesota with Great River Energy which should be operational by 2023. Wider commercial applications are planned for 2025. By using iron, the battery is very heavy so only suitable for batteries that are fixed in place. The battery is not suitable for electric vehicles or other devices.

The battery is composed of cells filled with thousands of little iron pellets that rust when exposed to oxygen. This process releases energy. When the battery is being recharged the application of an electrical current converts the rust back to iron and the battery breathes out oxygen.

Each individual battery is the size of a washing machine. The module is filled with a water based non flammable electrolyte (similar to the the electrolyte in AA batteries). Inside the liquid electrolyte are stacks of iron electrodes and air electrodes. These are the parts of the battery that enable the electrochemical reactions that store and discharge the electricity.

The modules are then grouped together in megawatt scale power blocks. Depending upon the size of the system, 10’s to 100’s of these blocks are connected to the electricity grid. Higher density configurations can deliver greater than 3 megawatts per acre of storage. The systems can be sited anywhere, including in urban areas to meet utility scale energy needs. The battery is a complement to lithium-ion batteries (which are faster response batteries and used for grid firming).

Shape Memory Alloys for Cooling

Exergyn, a Dublin based startup, has developed a shape memory alloy (SMA) that will revolutionize cooling and heating.

SMA’s are a group of materials with the unusual ability to return to a predetermined shape when they are heated. They are used in spectacle frames and medical implants such as stents. Exergyn uses Nitinol which is a blend of nickel and titanium.

SMA’s release heat when deformed by compression and then reabsorb heat when the pressure is released and they return to their original state. Nitinol does this to a remarkable degree. Exergyn produced a 4cm square plate of the alloy, pierced by holes through which a heat carrying liquid can be passed.

A refrigerator or air conditioner can be built using 4 stacks of 50 or so of these plates. The stacks are compressed by hydraulic rams or electric actuators in a sequence that works a bit like a four stroke engine. Where one stack is being compressed, one is released, one preheated and one pre-cooled, all at the same time.

Cooling a room involves passing two circuits of the heat carrying fluid through this four stack unit (see the diagram above). Fluid in a “cold” circuit first travels through a heat exchanger situated in the room to be cooled down, it absorbs warmth as it passes through. The fluid is then directed by a series of valves and pumps into whichever core is undergoing its’ relaxation stroke. The relaxing nitinol absorbs the head and the fluid is pumped to the heat exchanger for the process to be repeated. Accumulated heat is then dumped into the outside world via an external cooling unit.

The unit will be more environmentally friendly as it uses no gases or other coolants, it will be less expensive than conventional air conditioners to buy and be 30% to 40% cheaper to run. The systems will be lighter and smaller allowing them to be retrofitted into existing buildings and systems. It is estimated that the core unit should last for more than 40 years.

The system will be able to provide refrigeration, air conditioning, heating and cooling in a range of settings. Exergyn is working with an unnamed US air conditioning manufacturer (speculated to be Carrier) to commercialize the product. Products should start to appear in the next few years.

Self Healing Smartphone Screens

We have all dropped our phones and desperately hoped that we have not cracked the screen. Researchers at the Indian Institute of Science and Education Research (IISER) in Kolkata may have solved the problem. They have developed a self healing crystalline material that when broken can reassemble the broken pieces into the original form.

The material is piezoelectric which means that it can convert mechanical energy into electricity and vice-versa. Piezoelectricity plays a major role in initiating self healing in things such as damaged bones and collagen following a mechanical injury.

Individual needle shaped crystals about 2 millimeters long and 0.2 wide join together due to powerful attractive forces developed between their surfaces. When a fracture occurs these forces join the piece back together without the need for any external force such as heat or electricity.

Unlike other self healing materials, which tend to be soft and amorphous, this material is up to ten times harder and has a crystalline structure which is ideal for electronics. To be used in smartphones the material would need to be able to respond when touched etc. however experiments have already shown that the material exhibits strong polarization and non-linear optical response. This makes it ideal for optical sensing, high precision metrology (measurement) and optical nano probing. Further development may allow phones to self heal as well.

Self Driving Excavators

We talk a lot about self driving cars and other autonomous vehicles however there is plenty of application for this technology in industrial and construction settings that doesn’t get the same level of attention. Researchers from the University of Maryland have developed an autonomous excavator system.

The excavator can perform material loading tasks for a long duration with any human intervention with a performance that is closely equivalent to an experienced human operator. The system can operate 24 hours a day. The excavator must be able to identify target materials, avoid obstacles, handle uncontrollable environments and continue to run under difficult weather conditions.

Given the projected growth in the construction industry and the difficulty in hiring skilled heavy machinery operators this type of equipment will fill a void that is rapidly growing in the construction industry. The equipment can operate in dangerous conditions where human operators face significant personal risk. Excavation accidents cause approximately 200 casualties in the US each year.

An update to last week’s newsletter

Yes already. Last week we spoke about the release of RoseTTAFold which improved Google’s AlphaFold performance in estimating protein folding structures from a few days to 10 minutes.

This week AlphaFold responded by releasing 350,000 protein structure predictions. This will cover all, approximately 20,000, proteins expressed by the human genome or the entire human proteome. In addition to the human proteome, 20 biologically significant organisms (e.g. E.Coli, fruit fly, mouse, malaria parasite and tuberculosis bacteria) protein structures have been released.

The data is freely available to the scientific community. If you are interested you can find the data here. AlphaFold plans to expand the database to cover almost every sequenced protein known to science, over 100 million structures.

Paying it Forward

If you have a start-up or know of a start-up that has a product ready for market please let me know. I would be happy to have a look and feature the startup in this newsletter. Also if any startups need introductions please get in touch and I will help where I can.

If you have any questions or comments please email me via my website or comment below.

I would also appreciate it if you could forward this newsletter to anyone that you think might be interested.

Till next week.