Betavoltaic Battery Rated To Provide Power For 50 Years

A newly introduced battery called the BV100 by Chinese Betavolt Technology promises to provide half a century of power, at 100 μW in a 15x15x5 mm package. Inside the package are multiple, 2 micron-thick layers nickel-63 isotope placed between 10 micron-thick diamond semiconductor, with each diamond layer using the principle of betavoltaics to induce an electrical current in a similar fashion to a solar panel using light. Ni-63 is a β emitter with a half-life of 100 years, that decays into copper-63 (Cu-63), one of the two stable forms of copper.

From the battery’s product page we can glean a bit more information, such as that the minimum size of the betavoltaic battery is 3x3x0.03 mm with one layer of Ni-63 and two semiconductor layers, allowing for any number of layers to be stacked to increase the power output within a given package. Also noted is that the energy conversion rate of the β energetic event is about 8.8%, which could conceivably be improved in the future.

Although this battery may seem new, it’s actually based on a number of years of research  in diamond semiconductors in betavoltaics, with V. S. Bormashov and colleagues in 2018 reporting on a similar diamond semiconductor with Ni-63 isotope layer battery. They noted a battery specific energy of 3300 mWh/g. Related research by Benjian Liu and colleagues in 2018 showed an alphavoltaic battery, also using diamond semiconductor, which shows another possible avenue of development, since alpha particles are significantly more energetic.

Whether we’ll see Betavolt’s BV100 or similar products appear in commercial products is still uncertain, but they plan to have a 1 Watt version ready by 2025, which when packaged into the size of an average Li-ion battery pack could mean a mobile power source that will power more than a pacemaker, and cost less than the nuclear batteries powering the two Voyager spacecraft and all active Mars rovers today.

The Thousand Year (Radioactive) Diamond Battery

The Holy Grail of battery technology is a cell which lasts forever, a fit-and-forget device that never needs replacing. It may seem a pipe-dream, but University of Bristol researchers have come pretty close. The catch? Their battery lasts a very long time, but it generates micropower, and it’s radioactive.

They’re using a thin layer of vapour-deposited carbon-14 diamond both as a source of beta radiation, and as a semiconductor material which harvests those electrons. They’re expected to be used for applications such as intermittent sensors, where they would slowly charge a supercapacitor which could release useful amounts of power in short bursts.

It’s being touted as an environmental win because the carbon-14 is sourced from radioactive waste, but against that it’s not unreasonable to have a concern about the things being radioactive. The company commercializing the tech leads with the bold question: “What would you do with a power-cell that outlasts the device it powers?“, to which we would hope the answer won’t be “Throw it away to be a piece of orphaned radioactive waste in the environment when the device it powers is outlasted”. We’ll have to wait and see whether devices containing these things turn up on the surplus market in a couple of decades.

Fortunately the carbon-14 lives not in cartoonish vats of radioactive green slime but safely locked away in diamond, about the safest medium for it to be in. The prototype devices are also tiny, so we’re guessing that the quantity of carbon-14 involved is also small enough to not be a problem. We’re curious though whether they could become a valuable enough commodity to be reused and recycled in themselves, after all something that supplies energy for decades could power several different devices over its lifetime. Either way, it’s a major improvement over a tritium cell.

Battery Engineering Hack Chat Gets Charged Up

Turn the clock back a couple of decades, and the only time the average person would have given much thought to batteries was when the power would go out, and they suddenly needed to juice up their flashlight or portable radio.  But today, high-capacity batteries have become part and parcel to our increasingly digital lifestyle. In fact, there’s an excellent chance the device your reading this on is currently running on battery power, or at least, is capable of it.

So let’s get to know batteries better. What’s the chemical process that allows them to work? For that matter, what even is a battery in the first place?

It’s these questions, and more, that made up this week’s Battery Engineering Hack Chat with Dave Sopchak. Our last Hack Chat of 2022 ended up being one of the longest in recent memory, with the conversation starting over an hour before the scheduled kickoff and running another half hour beyond when emcee Dan Maloney officially made his closing remarks. Not bad for a topic that so often gets taken for granted.

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How Low-Power Can You Go?

[lasersaber] has a passion: low-power motors. In a bid to challenge himself and inspired by betavoltaic cells, he has 3D printed and built a small nuclear powered motor!

This photovoltaic battery uses fragile glass vials of tritium extracted from keychains and a small section of a solar panel to absorb the light, generating power. After experimenting with numerous designs, [lasersaber] went with a 3D printed pyramid that houses six coils and three magnets, encapsulated in a glass cloche and accompanied by a suitably ominous green glow.

Can you guess how much power and current are coursing through this thing? Guess again. Lower. Lower.

Under 200mV and 20nA!

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