By Michael Pollick | Wealth of Geeks undefine

With greater energy storage comes greater responsibility – a reality the entire battery industry is currently facing.

When the demand for electric hoverboards led to the installation of inferior lithium-ion batteries, battery manufacturers were forced to take a fresh look at safety issues. When the batteries in certain electric vehicle models spontaneously ignited, the existing technology once again came under scrutiny. If a shift towards cleaner, greener electric power is to become a mainstream reality, the energy storage process needs to become generally safer.

An article in the journal Scientific American explores the issues facing the commercial and consumer battery industry today. With every innovation in battery chemistry or storage capacity comes a risk of failure, often resulting in dangerous fires or contaminations.

“Clearly, storing large amounts of energy is difficult from a physics standpoint; [the energy] would rather be somewhere else,” says Paul Denholm, a senior energy analyst at the National Renewable Energy Laboratory.

One of the immediate challenges for consumer battery manufacturers is a phenomenon known as thermal runaway. This is the root cause of many of the fires and explosions reported by owners of lithium-ion-powered devices, such as hoverboards or toy electric vehicles.

What is thermal runaway?

Many consumer batteries are composed of individual cells housed inside a protective shell or casing. When one of those cells overheats due to damage or poor design, the energy stored inside that cell is released as heat. This heat can damage the surrounding cells, creating a cascading effect that leads to ignition or a meltdown. Thermal runaway is believed to be responsible for many of the spontaneous battery fires in consumer products.

The current solution for thermal runaway is to physically separate each cell inside the casing, reducing the opportunity for a meltdown to spread. Another option is a mechanical “kill switch” that disrupts the circuit and discharges stored energy.

The price of portability

One inescapable scientific fact is that heat equals energy, and dissipating excess heat in a commercial battery array is a critical process. However, there is a difference between cooling down a stationary bank of batteries and the portable batteries installed in electric vehicles (EVs) and other consumer devices.

These portable batteries are exposed to a range of humidities, temperatures, and charging cycles, so they are more prone to experience thermal runaway

“The biggest thing that people become concerned about [for batteries in cars] is the ability to be able to tolerate abuse,” explains Joe Redfield, principal engineer at the Southwest Research Institute, a nonprofit engineering research and development group.

Do all types of batteries pose equal risks?

Most dry cell batteries, watch batteries, and consumer-grade rechargeable batteries have undergone extensive safety testing at the factory, but there are counterfeit versions on the market that do present a safety hazard for consumers. The main hazards from inferior dry cell batteries are chemical burns and accidental ingestion, not thermal runaway or spontaneous ignition.

Lead acid batteries

Lead acid batteries are considered a mature technology in the energy storage industry. The biggest risk from a lead acid battery is exposure to the diluted sulfuric acid stored inside the battery casing. Original lead-acid batteries allowed owners to replenish the acid/water solution by removing a cap, but modern sealed versions make exposure to corrosive chemicals much less likely. Most Uninterruptible Power Supply (UPS) systems use spill-resistant lead acid batteries because of their proven stability.

Spinning flywheels

Hydroelectric power plants rely heavily on spinning flywheels to generate electricity through a dynamo. Spinning flywheels have been in existence for decades and are generally located in restricted areas. The hazards of spinning wheel energy generation and storage are primarily mechanical. The flywheel’s 24/7 operating cycle often stresses the components, which can trigger a catastrophic failure if not contained or maintained regularly.

Sodium-sulfur batteries

Many modern high-capacity commercial batteries are combinations of chemicals that function as negative and positive charges for generating electricity. Such is the case with sodium-sulfur batteries, once considered to be a viable alternative to lithium-ion batteries. There are several risk factors associated with sodium-sulfur batteries, most notably their high operating temperatures and the volatile nature of pure sodium.

Sodium reacts violently when exposed to moisture, and the battery temperature must be maintained at 300 degrees Celsius or higher for maximum efficiency. For these reasons, there are only a limited number of active sodium-sulfur battery manufacturers in the world.

Fossil fuels

While most people would not consider natural gas, coal, or oil to be in the same category as dry cell batteries, these natural materials do contain significant amounts of stored energy. The hazards of fossil fuels are largely environmental, starting with the extraction process, moving to storage, and finally to public consumption. Fires and exposure to toxic fumes are common issues associated with fossil fuels.

Lithium-ion batteries

Lithium-ion batteries are perhaps the most familiar form of rechargeable batteries for consumers, but there is no single type of lithium-ion battery. Some pose less of a safety or environmental issue than others. Small watch batteries used in watches, calculators, and other electronic devices are not prone to thermal runaway, but they can be accidentally ingested.

Larger lithium-ion batteries, such as the ones used for power tools or small electric motors, can become damaged to the point of thermal runaway or complete failure.

While lithium-ion batteries have become dominant in the marketplace, they have also become the benchmark for newer battery technologies to surpass. Lithium-ion batteries nearing their final charging cycles can also be hazardous to users.

Lithium-sulfur batteries

One of the more promising metal/chemical combinations in recent years is the lithium-sulfur battery, with the potential to replace more expensive lithium-ion batteries in the future. The main drawback with current lithium-sulfur batteries is the corrosive nature of sulfur. The sulfur dissolves over time in the liquid designed to keep the lithium and sulfur separated in cells. The result is a major reduction in energy storage and recharging cycles.

Professor Yuichi Negishi of Tokyo University of Science (TUS) explains the potential of a lithium-sulfur battery (LSB), “LSBs with metal nanoclusters may find applications in electric vehicles, portable electronics, renewable energy storage, and other industries requiring advanced energy storage solutions.

“In addition, this study is expected to pave the way for all-solid-state LSBs with more novel functionalities,” highlights Prof. Negishi. In the near future, the proposed technology can lead to cost-efficient and longer-lasting energy storage devices. This would help reduce carbon emissions and support renewable energy adoption, promoting sustainability.”

The future of energy storage and consumer safety

While the focus of future battery and energy storage development seems to be cheaper, stronger, and faster, most researchers are also putting a premium on safer. Instead of building compartments for heavy lead acid batteries, future electric vehicles may incorporate carbon fibers into the structure of the body, with a lithium iron phosphate providing the positive charge. The result would be a lighter vehicle with a safer rigid structure.

Instead of sourcing cobalt as a cathode for lithium-ion batteries, future models would use safer components such as nickel, aluminum, and manganese. Not only would these batteries charge up to 80% in five minutes, but they would also provide up to 500 miles of drive time on a single charge.
Finally, IBM and Mercedes-Benz are teaming up to develop EV batteries with components derived from seawater. These batteries would require no heavy metals and provide greater energy density on a faster charge cycle.

This article was produced by Media Decision and syndicated by Wealth of Geeks. It was redistributed from The Associated Press.

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