Solar Cell Solutions to Industry’s Biggest Hurdle – Degradation – UCLA Samueli School of Engineering


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Materials scientists at the UCLA Samueli School of Engineering and colleagues from five other universities around the world have discovered the major reason why perovskite solar cells — which show great promise for improved energy-conversion efficiency — degrade in sunlight, causing their performance to suffer over time.  

The team successfully demonstrated a simple manufacturing adjustment to fix the cause of the degradation, clearing the biggest hurdle toward the widespread adoption of the thin-film solar cell technology. 

  

A research paper detailing the findings was published in Nature. The research is led by Yang Yang, a UCLA Samueli professor of materials science and engineering and holder of the Carol and Lawrence E. Tannas, Jr., Endowed Chair. The co-first authors are Shaun Tan and Tianyi Huang, both recent UCLA Samueli Ph.D. graduates whom Yang advised. 

Perovskites are a group of materials that have the same atomic arrangement or crystal structure as the mineral calcium titanium oxide. A subgroup of perovskites, metal halide perovskites, are of great research interest because of their promising application for energy-efficient, thin-film solar cells.  

 

Perovskite-based solar cells could be manufactured at much lower costs than their silicon-based counterparts, making solar energy technologies more accessible if the commonly known degradation under long exposure to illumination can be properly addressed. For further information see the IDTechEx report on Energy Harvesting Microwatt to Gigawatt: Opportunities 2020-2040. 

   

“Perovskite-based solar cells tend to deteriorate in sunlight much faster than their silicon counterparts, so their effectiveness in converting sunlight to electricity drops over the long term,” said Yang, who is also a member of the California NanoSystems Institute at UCLA. “However, our research shows why this happens and provides a simple fix. This represents a major breakthrough in bringing perovskite technology to commercialization and widespread adoption.” 

  

A common surface treatment used to remove solar cell defects involves depositing a layer of organic ions that makes the surface too negatively charged. The UCLA-led team found that while the treatment is intended to improve energy-conversion efficiency during the fabrication process of perovskite solar cells, it also unintentionally creates a more electron-rich surface — a potential trap for energy-carrying electrons. 

  

This condition destabilizes the orderly arrangement of atoms, and over time the perovskite solar cells become increasingly less efficient, ultimately making them unattractive for commercialization. 

  

Armed with this new discovery, the researchers found a way to address the cells’ long-term degradation by pairing the positively charged ions with negatively charged ones for surface treatments. The switch enables the surface to be more electron-neutral and stable, while preserving the integrity of the defect-prevention surface treatments. 

  

 The team tested the endurance of their solar cells in a lab under accelerated ageing conditions and 24/7 illumination designed to mimic sunlight. The cells managed to retain 87% of their original sunlight-to-electricity conversion performance for more than 2,000 hours. For comparison, solar cells manufactured without the fix dropped to 65% of their original performance after testing over the same time and conditions. 

  

“Our perovskite solar cells are among the most stable in efficiency reported to date,” Tan said. “At the same time, we’ve also laid new foundational knowledge, on which the community can further develop and refine our versatile technique to design even more stable perovskite solar cells.” 

  

Source and top image: University of California Los Angeles 

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MIT Creates Waterless Cleaning System to Remove Dust on Solar Panels: Maintains Peak Efficiency and Service Longevity


The accumulation of dust on solar panels or mirrors is already a significant issue – it can reduce the output of photovoltaic panels. So regular cleaning is essential for such installations to maintain their peak efficiency. However, cleaning solar panels is currently estimated to use billions of gallons of water per year, and attempts at waterless cleaning are labor-intensive and tend to cause irreversible scratching of the surfaces, which also reduces efficiency. Robots can be useful; recently, a Belgian startup developed HELIOS, an automated cleaning service for solar panels.

Now, a team of researchers at MIT has now developed a waterless cleaning method to remove dust on solar installations in water-limited regions, improving overall efficiency.

The waterless, no-contact system uses electrostatic repulsion to cause dust particles to detach without the need for water or brushes. To activate the system, a simple electrode passes just above the solar panel‘s surface. The electrical charge it releases repels dust particles from the panels. The system can be operated automatically using a simple electric motor and guide rails along the side of the panel.

The team designed and fabricated an electrostatic dust removal system for a lab-scale solar panel. The glass plate on top of the solar panel was coated with a 5-nm-thick transparent and conductive layer of aluminum-doped zinc oxide (AZO) using atomic layer deposition (ALD) and formed the bottom electrode. The top electrode is mobile to avoid shading and moves along the panel during cleaning with a linear guide stepper motor mechanism. The system can be operated at a voltage of around 12V and can recover 95% of the lost power after cleaning for particle sizes greater than around 30 μm.

“We performed experiments at varying humidities from 5% to 95%,” says MIT graduate student Sreedath Panat. “As long as the ambient humidity is greater than 30%, you can remove almost all of the particles from the surface, but as humidity decreases, it becomes harder.”

By eliminating the dependency on trucked-in water, by eliminating the build-up of dust that can contain corrosive compounds, and by lowering the overall operational costs, such cleaning systems have the potential to significantly improve the overall efficiency and reliability of solar installations Kripa Varanasi says.

Monash Biomedicine Develops New Approach for Bolstering T-Cells Ability to Fight Cancer


Credit: CC0 Public Domain

A collaborative study led by the Monash Biomedicine Discovery Institute (BDI) has discovered a new immune checkpoint that may be exploited for cancer therapy

The study shows that by inhibiting the protein tyrosine phosphatase PTP1B in T cells, the body’s immune response to cancer can be mobilized, helping to repress tumor growth.

T cells are an essential part of the body’s immune system, helping not only to kill invading pathogens, such as viruses but also cancer cells. However, this study has shown that the abundance of PTP1B in T cells that infiltrate tumors is increased, thereby restraining the ability of T cells to attack tumor cells and combat cancer. These findings have identified PTP1B as an intracellular brake, or checkpoint, reminiscent of the cell surface checkpoint PD-1—the blockade of which has revolutionized cancer therapy. 

The findings are published in the prestigious journal Cancer Discovery.

Using mice, scientists from Monash BDI, in conjunction with colleagues at the Peter MacCallum Cancer Center in Melbourne and Cold Spring Harbor Laboratory in New York, found that by inhibiting PTP1B, using an early-stage injectable drug candidate that has previously been shown to be safe and well-tolerated in humans, the cancer-fighting ability of T cells is enhanced, repressing tumor growth.

Remarkably, the authors showed that the inhibition of this intracellular checkpoint, PTP1B, can also enhance the response to a widely used cancer therapy that blocks the PD-1 checkpoint on the surface of T cells.

Senior author Professor Tony Tiganis says that although the blockade of PD-1 can be highly effective against many tumors, not all patients respond and the development of resistance is common. This is true even for immunotherapy-sensitive cancers, such as melanoma. Approaches that can enhance the effectiveness or extend the utility of PD-1 checkpoint blockade are highly sought after in the clinic.

“While more pre-clinical work is needed, our findings show that superior outcomes were achieved when we combined PTP1B inhibition with existing immunotherapies in mice,” said Professor Tiganis.

In addition, beyond enhancing the response to PD-1 blockade, the authors showed that the inhibition of PTP1B also significantly enhanced the effectiveness of cellular therapies using Chimeric Antigen Receptor (CAR) T cells.

CAR T cells are T cells derived from a patient’s blood that are modified in the lab so that they produce a man-made receptor to help them better identify tumor cells and then injected back into the patient. 

CAR T cells have been highly effective against some blood cancers; however, this success has not, as yet, been replicated in solid tumors. The authors demonstrate that the deletion or inhibition of PTP1B can dramatically enhance the ability of CAR T cells to attack solid tumors in mice, including breast cancer. 

“To advance this work, a key next step will be to further define the impact of PTP1B deletion in CAR T and conventional T cells in humans. There remains an urgent clinical need to identify and validate cellular targets to revive and sustain T cell responses in cancer,” said first author Dr. Florian Wiede.

Professor Tiganis and Dr. Wiede will also continue to collaborate with Cold Spring Harbor Laboratory and DepYmed Inc., a US-based company developing PTP1B inhibitors, to test in their preclinical models orally bioavailable PTP1B inhibitor drug candidates as novel checkpoint inhibitors. These findings could form the basis of future clinical trials.

Cancer continues to be a major cause of illness and death in Australia, accounting for 30 percent of all deaths in Australia in 2020. The AIHW cancer in Australia report estimates that around 185,000 cases of cancer will be diagnosed in 2031 and that between 2022 and 2031, a total of around 1.7 million cases of cancer will be diagnosed.

The full paper in Cancer Discoveryjournal is titled “PTP1B is an intracellular checkpoint that limits T cell and CAR T cell anti-tumor immunity.”

ONE (Our Next Energy) Raises $65M to Accelerate Plans for First US factory – Tests New Prototype Battery in Tesla Model S – Achieves 752 Mile Range


Michigan-based energy storage technology company, Our Next Energy (ONE), has raised an additional $65 million in a new funding round led by BMW i Ventures. The new funding round will allow ONE to expand its operations and prepare for increasing demand and customer activity.

It also announced that it has signed contracts with four customers totaling more than 25 GWh of energy storage capacity over the next five years, equating to approximately 300,000 electric vehicle battery packs. This development allows ONE to begin the process of site selection for its first US-based battery factory.

Last year, the company demonstrated its proof-of-concept Gemini battery that powered an electric vehicle 752-mile (1,210-km) without recharging. In late December. It retrofitted a Tesla Model S with an experimental battery for real-world road testing across Michigan, where the test vehicle achieved 882 miles (1,419 km) at an average speed of 55 mph (88.5 km/h).

“This most recent investment accelerates the timeline for ONE’s Gemini battery technology following our recent 752-mile range demonstration. We are excited to have BMW i Ventures lead this round, and we are thrilled to welcome Coatue Management and their support as we raise the capital required to build a U.S. cell factory that supports Aries and Gemini,” said Mujeeb Ijaz, Founder, and CEO of ONE.

The ONE battery factory wants to accelerate electrification with safer, more powerful energy storage technologies that use more sustainable raw materials while creating a reliable, low-cost, and conflict-free supply chain.

ONE will begin evaluating site locations for its US-based battery factory, where production will start on its first product, a smaller battery cell called Aries, in late 2022. It expects to demonstrate a production prototype of the Gemini dual-chemistry battery in 2023.

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Read About ONE (Our Next Energy)

A Potentially ‘Powerful Alliance – ‘Sony and Honda Join Forces to develop Electric Vehicles


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The electric car market is creating alliances that were unpredictable until yesterday. The most recent example is Japan’s manufacturing giant Honda motors and Sony Group Corporation that, have signed a memorandum of understanding (MOU) to establish a joint venture through which they plan to engage in the joint development and sales of high value-added battery electric vehicles (EVs) and commercialize them in conjunction with providing mobility services.

The two companies will proceed with a goal of establishing the New Company within 2022, and the sales of the first EV model are expected to start in 2025.

In 2020, Sony unveiled a prototype car, the Vision-S, and soon after, the company was looking for an important partner with experience in the mobility sector. At this year’s CES, the company unveiled a new concept SUV dubbed Vision-S 02. It is now pressing ahead with its vision through the new partnership with Honda.

The agreement also opens the doors to other partners interested in the electric mobility revolution, which also counts on technological giants such as Alphabet with Waymo platform and Apple with the elusive Titan Project. There are also significant investments underway in electric cars by Ford, General Motors, Volkswagen, Toyota, and other famous car brands.

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                      Sony ‘Vision S -02: Concept Model

The roles that the two partners will play are very clear: Honda will handle the development and production of the cars and after-sales services that are essential for customer satisfaction. Sony, on the other hand, will deal with technologies present in cars, including onboard entertainment, a sector in which Sony boasts a world leadership.

The New Company is expected to plan, design, develop, and sell the electric vehicles but not own and operate manufacturing facilities, so Honda is expected to be responsible for manufacturing the first EV model at its vehicle manufacturing plant. It is expected that a mobility service platform will be developed by Sony and made available for the New Company.

“Sony’s Purpose is to ‘fill the world with emotion through the power of creativity and technology,” said Kenichiro Yoshida, Representative Corporate Executive Officer, Chairman, President, and CEO, Sony Group Corporation. “Through this alliance with Honda, which has accumulated extensive global experience and achievements in the automobile industry over many years and continues to make revolutionary advancements in this field, we intend to build on our vision to ‘make the mobility space an emotional one,’ and contribute to the evolution of mobility centered around safety, entertainment, and adaptability.”

Green hydrogen: the world’s largest project announced in Texas


green-hydrogen_060322The largest green hydrogen project in the world has just been unveiled! Named Hydrogen City, it will produce several million tons of green hydrogen every year…

With a capacity of 60 GW, Hydrogen City is a project led by the American startup Green Hydrogen International (GHI), which was founded in 2019 by renewable energy expert Brian Maxwell.

This mega-plant will be located in Duval County, a sparsely populated area located in southern Texas. It will be powered by wind and solar energy. Pipelines will transport the hydrogen produced to the port cities of Corpus Christi about 145 km away and Brownsville on the Mexican border.

The project will also have a cavern located inside the Salt Dome of Piedras Pintas that will allow on-site storage of the hydrogen produced. GHI claims that it will be possible to create about fifty similar caves in this area. This will allow Hydrogen City to store up to 6 TWh of energy.

Green Hydrogen International

Hydrogen City, Texas – World’s Largest Green Hydrogen Production and Storage Hub

A colossal production

Once finalized, Hydrogen City is expected to produce more than 2.5 million tons of green hydrogen per year, which currently corresponds to nearly 3.5% of global gray hydrogen production.

The first phase of 2 GW of the project will begin in 2026 with the creation of two storage caverns.

New method Using Aluminum Nanoparticles Creates Rapid, Efficient Hydrogen Generation from Water – UC Santa Cruz


Aluminum is a highly reactive metal that can strip oxygen from water molecules to generate hydrogen gas. Now, researchers at UC Santa Cruz have developed a new cost-effective and effective way to use aluminum’s reactivity to generate clean hydrogen fuel.

In a new study, a team of researchers shows that an easily produced composite of gallium and aluminum creates aluminum nanoparticles that react rapidly with water at room temperature to yield large amounts of hydrogen. According to researchers, the gallium was easily recovered for reuse after the reaction, which yields 90% of the hydrogen that could theoretically be produced from the reaction of all the aluminum in the composite.

“We don’t need any energy input, and it bubbles hydrogen-like crazy. I’ve never seen anything like it,” said UCSC Chemistry Professor Scott Oliver.

The reaction of aluminum and gallium with water works because gallium removes the passive aluminum oxide coating, allowing direct contact of aluminum with water.

Using scanning electron microscopy and x-ray diffraction, the researchers showed the formation of aluminum nanoparticles in a 3:1 gallium-aluminum composite, which they found to be the optimal ratio for hydrogen production. In this gallium-rich composite, the gallium serves both to dissolve the aluminum oxide coating and to separate the aluminum into nanoparticles.

“The gallium separates the nanoparticles and keeps them from aggregating into larger particles,” said Bakthan Singaram, corresponding authors of a paper on the new findings“People have struggled to make aluminum nanoparticles, and here we are producing them under normal atmospheric pressure and room temperature conditions.”

The researchers say the composite for their method can be made with readily available sources of aluminum, including used foil or cans. The composite can be easily stored for long periods by covering it with cyclohexane to protect it from moisture.

HF Z

While gallium is not abundant and is relatively expensive, it can be recovered and reused multiple times without losing effectiveness. However, it remains to be seen if this process can be scaled up to be practical for commercial hydrogen production.

Scientists discover new electrolyte for solid-state lithium-ion batteries


Chlorine-based electrolytes like the one shown here are offering improved performance for solid-state lithium-ion batteries. Credit: Linda Nazar/University of Waterloo

In the quest for the perfect battery, scientists have two primary goals: create a device that can store a great deal of energy and do it safely. Many batteries contain liquid electrolytes, which are potentially flammable.

As a result, solid-state lithium-ion batteries, which consist of entirely solid components, have become increasingly attractive to scientists because they offer an enticing combination of higher safety and increased energy density—which is how much energy the battery can store for a given volume.

Researchers from the University of Waterloo, Canada, who are members of the Joint Center for Energy Storage Research (JCESR), headquartered at the U.S. Department of Energy’s (DOE) Argonne National Laboratory, have discovered a new solid electrolyte that offers several important advantages.

This electrolyte, composed of lithium, scandium, indium and chlorine, conducts lithium ions well but electrons poorly. This combination is essential to creating an all-solid-state battery that functions without significantly losing capacity for over a hundred cycles at high voltage (above 4 volts) and thousands of cycles at intermediate voltage.

The chloride nature of the electrolyte is key to its stability at operating conditions above 4 volts—meaning it is suitable for typical cathode materials that form the mainstay of today’s lithium-ion cells.

“The main attraction of a solid-state electrolyte is that it can’t catch fire, and it allows for efficient placement in the battery cell; we were pleased to demonstrate stable high-voltage operation,” said Linda Nazar, a Distinguished Research Professor of Chemistry at UWaterloo and a long-time member of JCESR. 

Current iterations of solid-state electrolytes focus heavily on sulfides, which oxidize and degrade above 2.5 volts. Therefore, they require the incorporation of an insulating coating around the cathode material that operates above 4 volts, which impairs the ability of electrons and lithium ions to move from the electrolyte and into the cathode.

“With sulfide electrolytes, you have a kind of conundrum—you want to electronically isolate the electrolyte from the cathode so it doesn’t oxidize, but you still require electronic conductivity in the cathode material,” Nazar said.

While Nazar’s group wasn’t the first to devise a chloride electrolyte, the decision to swap out half of the indium for scandium based on their previous work proved to be a winner in terms of lower electronic and higher ionic conductivity. “Chloride electrolytes have become increasingly attractive because they oxidize only at high voltages, and some are chemically compatible with the best cathodes we have,” Nazar said. “There’s been a few of them reported recently, but we designed one with distinct advantages.

One chemical key to the ionic conductivity lay in the material’s crisscrossing 3D structure called a spinel. The researchers had to balance two competing desires—to load the spinel with as many charge carrying ions as possible, but also to leave sites open for the ions to move through. “You might think of it like trying to a host a dance—you want people to come, but you don’t want it to be too crowded,” Nazar said.

According to Nazar, an ideal situation would be to have half the sites in the spinel structure be lithium occupied while the other half remained open, but she explained that creating that situation is hard to design.

In addition to the good ionic conductivity of the lithium, Nazar and her colleagues needed to make sure that the electrons could not move easily through the electrolyte to trigger its decomposition at high voltage. “Imagine a game of hopscotch,” she said. “Even if you’re only trying to hop from the first square to the second square, if you can create a wall that makes it difficult for the electrons, in our case, to jump over, that is another advantage of this solid electrolyte.”

Nazar said that it is not yet clear why the electronic conductivity is lower than many previously reported chloride electrolytes, but it helps establish a clean interface between the cathode material and solid electrolyte, a fact that is largely responsible for the stable performance even with high amounts of active material in the cathode.

A paper based on the research, “High areal capacity, long cycle life 4 V ceramic all-solid-state Li-ion batteries enabled by chloride solid electrolytes,” appeared in the January 3 online edition of Nature Energy.

Other authors of the paper include Nazar’s graduate student, Laidong Zhou, a JCESR member who was responsible for the majority of the work, and Se Young Kim, Chun Yuen Kwok and Abdeljalil Assoud, all of UWaterloo. Additional authors included Tong-Tong Zuo and Professor Juergen Janek of Justus Liebig University, Germany and Qiang Zhang of the DOE’s Oak Ridge National Laboratory.

Explore further

New solid electrolyte promises cheaper, better all-solid-state lithium batteries

More information: Laidong Zhou et al, High areal capacity, long cycle life 4 V ceramic all-solid-state Li-ion batteries enabled by chloride solid electrolytes, Nature Energy (2022). DOI: 10.1038/s41560-021-00952-0

Journal information: Nature Energy 

Provided by Argonne National Laboratory

MIT’s Solar-Powered Desalination System More Efficient, Less Expensive


A team of researchers at MIT and in China has developed a new solar-powered desalination system that is both more efficient and less expensive than previous solar desalination methods. The process could be used to treat contaminated wastewater or to generate steam for sterilizing medical instruments, all without requiring any power source other than sunlight itself.

Many attempts at solar desalination systems rely on some kind of wick to draw the saline water through the device, but these wicks are vulnerable to salt accumulation and relatively difficult to clean. The MIT team focused on developing a wick-free system instead.

The system is comprised of several layers with dark material at the top to absorb the sun’s heat, then a thin layer of water above a perforated layer of material, sitting atop a deep reservoir of the salty water such as a tank or a pond. The researchers determined the optimal size for the holes drilled through the perforated material, which in their tests was made of polyurethane. At 2.5 millimeters across, these holes can be easily made using commonly available waterjets.

In this schematic, a confined water layer above the floating thermal insulation enables the simultaneous thermal localization and salt rejection.
In this schematic, a confined water layer above the floating thermal insulation enables the simultaneous thermal localization and salt rejection. Credit: MIT

With the help of dark material, the thin layer of water is heated until it evaporates, which can then be condensed onto a sloped surface for collection as pure water. The holes in the perforated material are large enough to allow for a natural convective circulation between the warmer upper layer of water and the colder reservoir below. That circulation naturally draws the salt from the thin layer above down into the much larger body of water below, where it becomes well-diluted and no longer a problem.

During the experiments, the team says their new technique achieved over 80% efficiency in converting solar energy to water vapor and salt concentrations up to 20% by weight. Their test apparatus operated for a week with no signs of any salt accumulation.

MIT-experimental solar desalResearchers test two identical outdoor experimental setups placed next to each other. Credit: MIT

So far, the team has proven the concept using small benchtop devices, so the next step will be starting to scale up to devices that could have practical applications. According to the researchers, their system with just 1 square meter (about a square yard) of collecting area should be sufficient to provide a family’s daily needs for drinking water. They calculated that the necessary materials for a 1-square-meter device would cost only about $4.

Off Grid Solar Desal

The team says the first applications are likely to be providing safe water in remote off-grid locations or for disaster relief after hurricanes, earthquakes, or other disruptions of normal water supplies. MIT graduate student Lenan Zhang adds that “if we can concentrate the sunlight a little bit, we could use this passive device to generate high-temperature steam to do medical sterilization” for off-grid rural areas.

Amprius Ships the World’s Highest Energy Density Battery Cells to HAPS Company – 450 Wh/kg, 1150 Wh/L with Proprietary Silicon Nanowire Technology


Californian company Amprius Technologies has announced the shipment of the first batch of its 450 Wh/kg, 1150 Wh/L lithium-ion battery cells to an industry leader of a new generation of High-Altitude Pseudo Satellites (HAPS). The company claims these are the most energy-dense lithium batteries commercially available today.

The batteries’ impressive performance is the result is Amprius Technologies’ silicon nanowire anode (Si-Nanowire platform), which offers a unique combination of performance metrics, including fast charge (under 10 minutes), high power (10C rates), high energy density (over 400 Wh/kg) and long life (over 500 cycles). The company was able to achieve 450 Wh/kg just a few months after announcing the 405 Wh/kg product in November 2021. In December, we also learned about the 370 Wh/kg version, which can be recharged to 80% from 0% state of charge in just about 6 minutes.

“This advancement from the 405 Wh/kg product highlights the acceleration of our roadmap towards delivering products with unrivaled performance,” said Jon Bornstein, COO of Amprius Technologies. “Our proprietary Si-Nanowire platform and the comprehensive solutions we have developed enable unparalleled performance and continue to sustain our product leadership.”

This shipment represents the culmination of collaborative development and testing for this latest design win. Currently, Amprius Technologies, which has been in commercial manufacturing since 2018, produces the battery cells at a limited scale at its facility in Fremont, California. The company has embarked on constructing its first high-volume manufacturing facility located in the United States. A mass production site will be selected in the first quarter of 2022.

More About Amprius Technologies

Amprius Technologies’ batteries deliver up to 100% higher energy density than standard lithium-ion batteries.  This means our cells provide more energy and power with much less weight and volume.

Research & development

Building on research at Stanford University, Amprius Technologies continually explores new ways to improve battery technology and manufacturing processes. Amprius Technologies’ batteries have established breakthrough performance with new cells approaching 500 Wh/kg over hundreds of cycles.

Real world applications

Amprius Technologies has demonstrated scalable manufacturing and revolutionary performance in real world applications. The company’s game changing battery is a proven solution for advanced products and mission critical applications.