However there is a debate over what constitutes the perfect, and most secure, sodium ion battery design. Plus, more than one, external US firm working on this area has floundered in recent years, external.
China leads the world in sodium ion battery manufacturing at current so US rivals are going to need to work exhausting to maintain up.
The prize that awaits is the opportunity of batteries made within the US with 100% US-sourced supplies. That is not like lithium ion batteries, the place China dominates the materials, external provide chain in addition to manufacturing.
For Tan, China has helped his firm get to market. The Unigrid battery at present makes use of sodium ion cells made there, quite than within the US. “We will change backwards and forwards and select what battery we wish to work with,” says Tan, explaining that, in future, his agency may supply cells from the US – although these could come at a special price.
There’s one other consideration. Unigrid’s battery accommodates chromium-3 in its cathode. In a battery, electrons flow from cathode to anode, external when charging and in the other way when discharging or offering energy.
Prof Dame Clare Gray on the College of Cambridge, who’s co-founder of battery agency Nyobolt, factors out that underneath sure situations chromium-3 could kind chromium-6, a poisonous, cancer-causing material., external
“If you are going to go for sodium […] and you are going to promote security, then do not begin placing components in which might be going to lift pink flags,” she tells the BBC.
Ivana Hasa, on the Warwick Manufacturing Group, College of Warwick, who has no connection to Unigrid, agrees that it’s attainable for chromium-3 to kind chromium-6 at very excessive states of cost, although she says this may be mitigated by how voltage is managed inside the battery. “Security assessments reported on the cell chemistry are very promising,” she says of Unigrid’s tech.
Tan says issues round toxicity of the battery’s supplies are “overblown” and emphasises that Unigrid’s battery has handed certification and security assessments on the market in Europe and is at present present process such evaluations for the US market.
Third-party assessments haven’t been capable of get the battery to kind chromium-6, he says. “We have tried very exhausting to try to produce it, we have overcharged it as a lot as we will… We had been unsuccessful in producing chromium-6.”
The selection of cathode materials, or how the electrolyte – which separates cathode and anode – is formulated are key particulars influencing the efficiency and longevity of sodium ion batteries. Some producers aren’t utilizing chromium for his or her cathode however exhausting carbon as a substitute, or sodium iron phosphate pyrophosphate (NFPP).
Normally, confidence round sodium ion batteries’ reliability has elevated throughout the previous few years, says Prof Dame Gray, that means they’re now discovering their means into grid storage functions.
Final December, LFP batteries – a comparatively low-cost type of lithium ion battery – were trading at $81 per kilowatt hour, external (kWh) whereas Unigrid’s sodium ion battery pricing is roughly $100 kWh, external.
Some firms that spoke to the BBC steered sodium ion may attain as little as $30 per kWh however analysts say considerably decrease prices could be many years away, external.
Sodium ion batteries are additionally not as vitality dense as lithium ion batteries, that means they should be barely greater and heavier as a way to present the identical quantity of energy.
The know-how has been improving, external on this entrance in recent times however, even so, you are not prone to see sodium ion cells in small, vitality hungry units resembling smartphones. Bigger vitality storage options are the place most individuals count on sodium ion to dominate.
