Solar Energy

Batteries are a hot topic for SPARRCI researchers

Published

4 years ago

March 2, 2021

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Batteries are a hot topic for SPARRCI researchers

If you have flown commercially in recent years, you may have noticed that certain items with large lithium-ion batteries can’t be checked. Instead, they must be in your carry-on and turned off.

Objects with these batteries, such as hoverboards or even cell phones, have been known to spontaneously combust, especially if they are physically damaged somehow. The resulting fire presents a danger to people in their vicinity.

So, if these batteries aren’t allowed on airplanes unsupervised, using them to propel the fully electric aircraft of the future may come with some challenges and questions about safety.

Exploring the feasibility of predicting and preventing battery fires before they happen is the idea behind a NASA research activity called SPARRCI, or “Sensor-based Prognostics to Avoid Runaway Reactions and Catastrophic Ignition.”

The big goal is to create a “smart” battery system that would self-monitor, learn about itself as it goes, and if needed say “hey, I’m developing a problem, shut me down” well before it endangers the safety of its aircraft.

“Batteries are a hot topic. Pun intended,” said Brianne DeMattia, lead researcher for SPARRCI at NASA’s Glenn Research Center in Cleveland.

One of the safety threats posed by batteries in electrically propelled aircraft is fire. These larger batteries, like those needed to power hoverboards and cars, have been known to catch fire because of an effect called “thermal runaway.”

Large batteries are basically many cells of small batteries packaged together. If one cell has a malfunction and starts to heat up in temperature, it causes the neighboring cell to do the same. Eventually, the whole battery overheats and could start a fire.

Battery sensors like the ones used by our phones and computers only measure the temperature outside the battery. SPARRCI is designing batteries with sensors inside them to identify the conditions that lead to thermal runaway, then alert the aircraft’s operator to the potential trouble.

The operator would then be able to correct the problem or replace the battery before the dangerous overheating ever occurs. This new, fine-tuned view of the inside of a battery could lead to safer and better performing energy storage – a new generation of batteries.

“With current batteries, we just try to contain fire so it doesn’t spread. But the best approach is to try and prevent the overheating and fire entirely. That’s what we’re trying to do with SPARRCI,” DeMattia said.

Size Matters

Another research area of SPARRCI is battery size and power storage.

A typical remote control for a television uses a couple of AA-sized batteries. A small electric aircraft such as the X-57 Maxwell, NASA’s first all-electric aircraft, may need a battery with the equivalent power of more than 5,000 AA-sized batteries.

Currently, large batteries providing that kind of power must be packaged in bulky containers to make sure that if something gets hot or catches fire, the heat is insulated, protecting other battery cells and the vehicle.

The size and weight of these containers could be reduced in the future with SPARRCI’s ability to show what’s going on inside the battery.

If the aircraft’s pilot or maintenance crew know that thermal runaway could occur, the battery can be replaced and never have a chance to catch fire.

If fire isn’t a threat anymore, extra insulation isn’t required, and the battery’s overall size and weight can be reduced. This would allow more space inside the vehicle to be dedicated to energy storage, improving its range and available power.

Since the activity began in 2020, SPARCCI researchers have successfully begun working out how to install sensors inside batteries. The next step? Identify what conditions the sensors inside the battery should look for to detect imminent battery problems or failures.

The View Inside

SPARRCI is part of the Convergent Aeronautics Solutions (CAS) project, which is designed to give NASA researchers the resources they need to determine if their ideas to solve some of aviation’s biggest technical challenges are feasible and perhaps worthy of additional pursuit within NASA or industry.

One of the things that makes CAS activities like SPARRCI unique is the requirement for researchers from different technical disciplines and NASA field centers to collaborate and bring their unique expertise to bear on the problem.

For SPARRCI, that collaboration led to some memorable moments for battery and sensor researchers at NASA’s Langley Research Center in Virginia, who have been working with their counterparts at NASA Glenn.

The Langley researchers evaluated batteries from Glenn using a Scanning Electron Microscope (SEM), a device similar to the ultrasound machines used in doctors’ offices and hospitals.

“Our goal was to collect images of the guts of the battery during a test without having to open them up post-mortem. This allowed us to see conditions changing in real time and run non-destructive scans to get a sense of the ‘topography’ of the internal surfaces as they morphed during operation,” DeMattia said.

What they saw during the scans was, well, out of this world.

“As we used the SEM to scan images of these lithium metal surfaces inside the battery they sometimes looked like the surface of the Moon! It was one of the coolest things. We spent hours around the computer, ‘oohs’ and ‘ahs’ often thrown around, with an occasional ‘What on Earth is that?’ thrown in for good measure.”

“It’s not something that any of us have done or seen before, but the images did help us tie together the data we collected,” DeMattia said. “”We couldn’t have done this without the different disciplines coming together. It has been really exciting.”

SPARRCI was selected to be a two-year activity that began on Oct. 1, 2019. Interruptions in the pursuit prompted by the COVID-19 pandemic might lead to an extension, although nothing has been decided yet.

Once completed, information gathered, and experience gained during SPARRCI will be shared with others within NASA and the broader aviation community.

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Solar Energy

Scientists Probe Declining Earbud Battery Longevity

Published

2 hours ago

February 5, 2025

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Scientists Probe Declining Earbud Battery Longevity

by Clarence Oxford

Los Angeles CA (SPX) Feb 05, 2025

Have you ever noticed how electronic devices, including wireless earbuds, seem to lose battery capacity faster the longer you use them? An international research team from The University of Texas at Austin set out to examine this familiar issue, known as battery degradation, by focusing on the earbuds that many people rely on daily. Through a series of x-ray, infrared, and other imaging approaches, the researchers investigated the hidden complexities behind these tiny devices and revealed why their battery life declines over time.

“This started with my personal headphones; I only wear the right one, and I found that after two years, the left earbud had a much longer battery life,” said Yijin Liu, an associate professor in the Cockrell School of Engineering’s Walker Department of Mechanical Engineering, who led the new research published in Advanced Materials. “So, we decided to look into it and see what we could find.”

Their analysis showed that crucial earbud features – like the Bluetooth antenna, microphones, and circuits – compete with the battery in a very confined space, producing a microenvironment that is less than ideal. This situation results in a temperature gradient that damages the battery over time, with different sections of the cell experiencing variable temperatures.

Real-world factors also complicate matters. Frequent changes in climate, shifts in air quality, and a host of other environmental variables challenge the battery’s resilience. While cells are generally designed to endure harsh conditions, constant fluctuations can take their toll.

These discoveries highlight the importance of considering how batteries interact with devices such as phones, laptops, and even electric vehicles. Packaging solutions, strategic design decisions, and adaptations for user habits may all play a role in extending battery performance.

“Using devices differently changes how the battery behaves and performs,” said Guannan Qian, the first author of this paper and a postdoctoral researcher in Liu’s lab. “They could be exposed to different temperatures; one person has different charging habits than another; and every electric vehicle owner has their own driving style. This all matters.”

In conducting this study, Liu and his team worked closely with UT’s Fire Research Group, led by mechanical engineer Ofodike Ezekoye. They paired infrared imaging methods with their in-house x-ray technology at UT Austin and Sigray Inc. To expand their scope, they then teamed up with some of the world’s most advanced x-ray facilities.

Their collaborators included researchers from SLAC National Accelerator Laboratory’s Stanford Synchrotron Radiation Lightsource, Brookhaven National Laboratory’s National Synchrotron Light Source II, Argonne National Laboratory’s Advanced Photon Source, and the European Synchrotron Radiation Facility (ESRF) in France. These partnerships allowed them to observe battery behavior under more authentic operating conditions.

“Most of the time, in the lab, we’re looking at either pristine and stable conditions or extremes,” said Xiaojing Huang, a physicist at Brookhaven National Laboratory. “As we discover and develop new types of batteries, we must understand the differences between lab conditions and the unpredictability of the real world and react accordingly. X-ray imaging can offer valuable insights for this.”

Looking ahead, Liu says his team will continue analyzing battery performance in the settings people experience every day. They plan to expand their approach to larger batteries, such as those in smartphones, laptops, and electric vehicles, to learn more about their degradation patterns.

Research Report:In-device Battery Failure Analysis

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Solar Energy

Quantum factors elevate plant energy transport efficiency

Published

2 hours ago

February 5, 2025

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Quantum factors elevate plant energy transport efficiency

by Robert Schreiber

Munich, Germany (SPX) Feb 05, 2025

For countless engineers, converting sunlight into easily stored chemical energy stands as an enduring goal. Yet nature perfected this challenge billions of years ago. A recent study reveals that quantum mechanics, once thought to be limited to physics, is also essential for key biological processes.

Green plants and other photosynthetic organisms draw on quantum mechanical mechanisms to capture the sun’s energy. According to Prof. Jurgen Hauer: “When light is absorbed in a leaf, for example, the electronic excitation energy is distributed over several states of each excited chlorophyll molecule; this is called a superposition of excited states. It is the first stage of an almost loss-free energy transfer within and between the molecules and makes the efficient onward transport of solar energy possible. Quantum mechanics is therefore central to understanding the first steps of energy transfer and charge separation.”

Classical physics alone cannot completely describe how this phenomenon unfolds throughout green plants and in certain photosynthetic bacteria. Although the exact details remain only partly understood, Prof. Hauer and first author Erika Keil consider their new findings an important step toward uncovering how chlorophyll, the pigment behind leaf coloration, functions. Applying these insights to engineered photosynthesis devices could unlock unprecedented solar energy conversion efficiencies for both power production and photochemical applications.

In their investigation, the researchers focused on two portions of the light spectrum absorbed by chlorophyll: the low-energy Q band (yellow to red) and the high-energy B band (blue to green). In the Q region, two electronic states are quantum mechanically coupled, promoting virtually loss-free energy movement. The system subsequently relaxes via “cooling”, i.e. by releasing energy in the form of heat. These observations demonstrate that quantum mechanical processes can play a major role in shaping key biological functions.

Research Report:Reassessing the role and lifetime of Qx in the energy transfer dynamics of chlorophyll a

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Solar Energy

HZB sets new efficiency record for CIGS perovskite tandem solar cells

Published

3 hours ago

February 5, 2025

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HZB sets new efficiency record for CIGS perovskite tandem solar cells

by Robert Schreiber

Berlin, Germany (SPX) Feb 05, 2025

Researchers at Helmholtz Center Berlin for Materials and Energy (HZB) and Humboldt University Berlin have developed a CIGS-perovskite tandem solar cell that has set a new world record for efficiency, achieving 24.6%. The performance of the cell has been officially certified by the Fraunhofer Institute for Solar Energy Systems.

Thin-film solar cells, such as those based on copper, indium, gallium, and selenium (CIGS), require minimal material and energy to manufacture, making them an environmentally friendly alternative to conventional silicon-based solar cells. CIGS thin films can also be applied to flexible substrates, expanding their potential applications.

The new tandem solar cell developed by HZB and Humboldt University combines a CIGS bottom cell with a perovskite top cell. By optimizing the contact layers between these two components, the research team successfully increased efficiency to a record-breaking 24.6%. This milestone was confirmed by the Fraunhofer Institute for Solar Energy Systems ISE in Freiburg, Germany.

This achievement was made possible through a collaborative effort among researchers. The top cell was developed by Thede Mehlhop, a master’s student at TU Berlin, under the supervision of Stefan Gall. The perovskite absorber layer was created in the joint laboratory of HZB and Humboldt University Berlin, while the CIGS sub-cell and contact layers were fabricated by HZB researcher Guillermo Farias Basulto. Additionally, the KOALA high-performance cluster system at HZB was used to deposit the perovskite and contact layers in a vacuum.

“At HZB, we have highly specialized laboratories and experts who are top performers in their fields. With this world record tandem cell, they have once again shown how fruitfully they work together,” said Prof. Rutger Schlatmann, spokesman for the Solar Energy Department at HZB.

HZB has a strong track record in achieving world records in solar cell efficiency, including past accomplishments in silicon-perovskite tandem cells and now in CIGS-perovskite tandem technology.

“We are confident that CIGS-perovskite tandem cells can achieve much higher efficiencies, probably more than 30%,” said Prof. Rutger Schlatmann.