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Types of Batteries Used in Robotics

There are many different types of batteries available on the market, but to keep things simple we’ll divide them into two groups.

There are batteries that are great for robots…

• Li-Ion — lithium-ion battery
• Li-Poly — lithium polymer batteries
• NiMH — nickel–metal hydride battery

…and batteries that are not that great (meaning, don’t use them):

• Lead-acid battery — all types (including VRLA, SLA, gel or AGM) don’t like charging-discharging cycles and works much better as a backup power supply for stationary applications. They also have low capacity per weight unit.
• NiCd — nickel-cadmium battery — similar to NiMH, but currently they are being withdrawn from use, because of toxic cadmium and no advantages over NiMH cells.
• NiH2 — nickel-hydrogen battery — have you ever heard about that one? Probably not, unless you were building the Hubble Space Telescope…

There are a couple of other types, however we won’t be discussing anything expensive, difficult to buy, or difficult to charge.

The table below will give you a general overview of the battery types mentioned above (the ones suitable for robots). There are many modern Li-Ion cells, which allow discharging them with current up to 90C, but the table would be 10 times wider if I wanted to describe all of them.

A new round of trade war tensions is sending metal markets into a tailspin.

Copper crashed through $6,000 a metric ton for the first time in a year and is heading for its biggest monthly drop since 2015. Zinc, lead, nickel and aluminum tumbled as the dollar rose for a third day. An index of copper-mining companies headed for the lowest close since 2016, paced by losses in Freeport-McMoRan Inc. and First Quantum Minerals Ltd.

Metals are accelerating a sell-off that started in early June over fears that the trade fight between China and the U.S. will dent economic growth, stunting demand for raw materials. On Thursday, China accused American officials of making false accusations and fired back against a claim President Xi Jinping is blocking talks with the U.S.

Read more: Global market calm at risk as commodities sink into correction

“Uncertainty dominates at this stage and investors are still very wary with all the trade protectionism and threats of retaliation we’re seeing,” Casper Burgering, senior sector economist at ABN Amro Bank, said by phone from Amsterdam. “You can clearly see that reflected in copper prices today.”

Metal prices spiked lower just after 8 a.m. in London, leading brokers to speculate that the move was driven by technical funds, also known as commodity trading advisers, adding short positions at the start of the European trading day.

“Given the timing of these moves, it would appear a CTA offer has re-emerged,” Alastair Munro, an analyst at Marex Spectron in London, said by email. This week, speculative short positions in copper have risen to the highest since a peak in January 2016, he said.

The rising tensions sent the yuan tumbling against the dollar, putting further pressure on buyers in China, the world’s leading consumer of industrial commodities. The currency is trading near its lowest in a year.

Copper dropped 1.4 percent to settle at $6,065 a ton at 5:51 p.m. on the London Metal Exchange. The metal earlier fell as much as 2.6 percent to $5,988 a ton, the lowest since July 2017. Prices have fallen more than 17 percent since early June, approaching the definition of a bear market.

Zinc, lead and nickel lost more than 2 percent, while tin rose. Aluminum dropped as inventories on the LME rose for a ninth day, in the longest run of gains since 2009.

APEX Insight: The risk of explosion associated with lithium-ion batteries has been a dilemma for the airline industry. Could one company’s solution put out the fire?

Lithium-ion (Li-ion) batteries are ubiquitous portable powerhouses in the world of rechargeable energy storage, with billions of cells produced annually. Found in everything from wireless earbuds to in-flight entertainment tablets, their pervasiveness extends to the aircraft cabin – but maybe not for long.

A Li-ion cell has a liquid electrolyte that saturates the battery’s key components, but is highly flammable. If a Li-ion cell is physically damaged, or if a battery’s charging circuitry malfunctions, the cell can become a raging inferno, spewing molten material with temperatures up to 1,985 degrees Fahrenheit – a thermal runaway that can destroy equipment and injure people. The safety risks associated with the use of Li-ion batteries have been known since Sony introduced the first one in 1991, with the Federal Aviation Administration (FAA) reporting 160 air or airport incidents involving Li-ion batteries from that point to mid-2017. The issue gained widespread attention in 2016, when Samsung announced a global recall on its Galaxy Note 7 after reports that the smartphone was self-combusting on the ground and in the air.

The threat of thermal runaway in batteries has since led to a controversial US electronics ban, the Airline Passenger Experience Association’s subsequent call for solutions to the ban and, as of February, decisions made by Delta, American, Alaska, Southwest and Hawaiian airlines to prohibit baggage with non-removable Li-ion batteries.

There is enough known about lithium-ion batteries to acknowledge that in the current architecture, they are a risk in an airplane,” – Erik Terjesen, Ionic Materials

“There is enough known about lithium-ion batteries to acknowledge that in the current architecture, they are a risk in an airplane,” says Erik Terjesen, senior director, Licensing and Strategy, Ionic Materials.

To solve the problem of thermal runaway, Ionic Materials has developed a unique polymer material – a solid plastic – that would entirely replace the liquid electrolyte in the battery. “You basically create a battery that is entirely solid, with no liquid component, that is non-flammable,” Terjesen says.

Ionic has tested the newly configured batteries to destruction, cutting cells in half, and firing bullets into the battery packs. Not only are the batteries stable, with no resulting explosions or fires, remarkably, the cells continue to provide power.

A next-generation “lithium-metal” battery using Ionic’s polymer could have roughly two to three times the energy density of a current Li-ion cell. And thanks to the polymer, even decades-old alkaline battery technology could see a reboot, becoming a rechargeable and inexpensive alternative to Li-ion cells. According to Terjesen, we could see safe and even more powerful batteries in the next few years.

If we can provide an inherently safe technology, that’s going to bring a lot more comfort,” – Erik Terjesen, Ionic Materials

“We’ve been in dialogue with people at the FAA and others – airlines and aviation players – and I think there’s the same view: If we can provide an inherently safe technology, that’s going to bring a lot more comfort,” Terjesen says.

Only two per cent of Australia’s annual 3,300 tonnes of lithium-ion battery waste is recycled, says the consultancy CSIRO in a report on Lithium-ion battery recycling published Wednesday.

The authors of the study want to emulate the same success that was achieved in recycling lead-acid batteries. Of the 150,000 tonnes of lead-acid batteries sold in 2010, CSIRO says 98 per cent were recycled.

The authors of the study are proposing a multi-pronged effort to encourage recycling of lithium-ion batteries. The advantage would be less environmental contamination and reducing the risk of fire from discarded lithium-ion batteries. The materials needed to make lithium-ion batteries are also costly and recycling can add to the supply.

Low battery recycling rates can be overcome through better understanding of the importance of recycling, improved collection processes, and by implementing ways to efficiently recycle materials, says CSIRO.

If lithium-ion batteries were recycled, 95 per cent of components can be turned into new batteries or used in other industries.

 

Lithium exploration and development company Bacanora Minerals won’t go ahead with a proposed $100 million share sale, citing volatile prices for the battery raw material as the main reason for the u-turn, it said Thursday.

Earlier this week, the company had announced the plan saying it would help it help fund the construction of its 17,500 tonnes-a-year lithium carbonate mine in Sonora, Mexico.

“Challenging market conditions have led us to take the decision not to proceed with the placing at this stage,” chief executive Peter Secker said in the statement.

Initially, investors reacted negatively to the news and the company’s shares dropped in London from 80p to 67p. The stock ended up closing 4.34% higher to 69.7p.

Bacanora said it will now focus on completing the Front End Engineering Design, while talks are ongoing with several additional parties to find alternative funding.

Sonora’s first phase is expected to cost $420 million with a further $40 million needed for working capital. A recent feasibility study assigned the asset a net present value of $1.25-billion and an internal rate of return of 26%.

The company plans to extract lithium from clay, a technology that has not yet been proven at mass scale. Bu that hasn’t stopped giants, such as Tesla Motors, from signing an agreement with the company and its partner Rare Earth Minerals that secure supply of lithium hydroxide from the Sonora project to the electric cars and energy storage products company.

In May 2017, Bacanora secured a $11 million investment from Blackrock. It came a few months after inking another long-term supply deal with Japan’s Hanwa Corporation, which will see the Tokyo-based trader acquire up to 100% of the output coming from Sonora.

Frequently referred to as “white petroleum,” lithium drives much of the modern world, as it has become an irreplaceable component of rechargeable batteries used in high tech devices and electric cars.

Investor are growing increasingly concerned about a wave of new lithium projects sprouting up from Australia to Nevada, which could put pressure on prices. Lithium carbonate, a key ion battery raw material, have climbed almost 40% in the past 12 months on the back of increasing electric car production, according to Benchmark Minerals Intelligence.

Shares in the world’s largest producers of lithium, however, have gone the opposite way this year, following double-digit gains in 2017.

Engineers at the University of California San Diego have shed new light on the atomic-level mechanism of the sulfur embrittlement of nickel, a classic problem that has puzzled the scientific community for nearly a century. The discovery also enriches fundamental understanding of general grain boundaries that often control the mechanical and physical properties of polycrystalline materials. An open-access paper on the work is published in Nature Communications.

The study was led by Jian Luo, a professor of nanoengineering and materials science and engineering at the UC San Diego Jacobs School of Engineering.

Since the early 1900s, engineers and scientists have recognized that sulfur impurities cause nickel and other ductile metals, such as iron and steel, to fail at low stress levels. Sulfur embrittlement of metals is of general technological importance because many engineered alloys are used in sulfur-bearing environments, such as the nickel-based high-temperature alloys used in next-generation coal-fired power plants for increasing energy efficiency.

Researchers have known that this embrittlement is related to the grain boundary segregation of sulfur, but the underlying atomic mechanisms have remained elusive.

UC San Diego engineers have shed new light on these mechanisms by examining general grain boundaries in nickel polycrystals doped by sulfur. They used a combination of aberration-corrected scanning transmission electron microscopy and semi-grand-canonical ensemble atomistic simulations.

Luo’s team found that competition between interfacial ordering and disordering leads to the alternating formation of amorphous-like and bilayer-like facets at general grain boundaries. They also found that bipolar interfacial structures cause brittle intergranular fractures between polar sulfur-nickel structures that are disorderly aligned in two opposite directions.

Similar mechanisms may cause grain boundary embrittlement in other metal-nonmetal systems. Examples include oxygen, sulfur, phosphorus and hydrogen embrittlement of other metals and alloys. These are of broad technological importance.

—Jian Luo

This work further advances previous research by Luo’s group on the bismuth embrittlement of nickel, which was done in collaboration with Lehigh University and published in two subsequent reports in Science in 2011 and 2017. Researchers discovered that highly-ordered interfacial structures form at general grain boundaries in bismuth-doped nickel. In the new Nature Communications study, Luo’s group found that disordered bipolar interfacial structures form in sulfur-doped nickel.

Bismuth and sulfur are two well-known embrittling impurities for nickel. Interestingly, we found that these represent two extreme cases of interfacial structures—ordered versus disordered, respectively. Thus, they may be considered as two classic examples of grain boundary embrittlement with different underlying atomistic structures.

—Jian Luo

Aside from embrittlement mechanisms, researchers say this study sheds new light on the mysterious abnormal grain growth phenomena in sulfur-doped nickel, and enriches fundamental understanding of disordered interfaces. This study also challenges a traditional view by showing that the orientation of the grain boundary facet, instead of the misorientation, dictates the interfacial structure.

This work broadens our fundamental knowledge of materials interfaces beyond the well-characterized ordered interfaces and special symmetric boundaries in artificial bicrystals that have been the focus of most prior studies. Now, we have new insight into the disordered interfaces and general grain boundaries in real-world polycrystals, which often limit the performance of most engineered materials.

—Jian Luo

Luo is also affiliated with the Sustainable Power and Energy Center at UC San Diego, where he is working on materials related issues for both energy storage and energy efficiency