The demand for Lithium-ion batteries is set to increase at a phenomenal pace. Estimates project that between 2022 and 2030, the global demand for these batteries will increase as much as seven-fold to reach 4.7 terawatt hours.
The demand is driven by the extensive use of these batteries in portable electronics and energy storage, including electric vehicles. However, these batteries are not risk-free. They are vulnerable to fire and explosion.
One solution to these vulnerabilities involves semi-solid batteries. They reduce risks by striking a middle ground between traditional lithium-ion batteries with liquid electrolytes and solid-state batteries.
A gel-like electrolyte, used as a component, helps these batteries get enhanced stability and longer lifespan. However, these gel electrolytes, owing to their prolonged heat treatment at high temperatures, may go through notable degradation, resulting in diminished performance and increased manufacturing costs. The fabrication process involved in producing these batteries also faces a challenge due to the interface resistance between the semi-solid electrolyte and electrode.
Recently, Professor Soojin Park, Seoha Nam, a PhD candidate, and Dr Hye Bin Son, a researcher at the Department of Chemistry at Pohang University of Science and Technology (POSTECH), have devised viable ways to tackle these challenges by creating a stable and commercially viable gel electrolyte-based battery.
In the coming segment, we delve deeper into understanding the mechanism of the battery.
Safe and Commercially Viable Gel Electrolyte for Lithium Batteries
In tackling the challenges of degraded electrolytes, diminished performance, and rising costs, the team of researchers leveraged bifunctional cross-linkable additive (CIA) and dipentaerythritol hexaacrylate (DPH) with electron beam (e-beam) technology.
The researchers walked differently from the conventional manufacturing process, which involved electrode preparation, electrolyte injection, assembly, activation, and degassing.
Instead, they enhanced DPH”s dual functionality by introducing an additional e-beam irradiation step after the degassing process. Meanwhile, the CIA served both as an additive to facilitate a stable interface between the anode and cathode surfaces during activation and as a crosslinker to form a polymer structure during the e-beam irradiation process.
The resulting solution could notably reduce gas generation from battery side reactions during initial charging and discharging processes. The decrease was as high as 25.5-fold compared to conventional batteries. The solution could also stably maintain interfacial resistance owing to strong compatibility between electrodes and the gel electrolyte.
However, the researchers did not stop at these achievements. They went on to develop a high-capacity battery of 1.2 ampere-hours, which was tested at a temperature of 55 degrees Celsius—a temperature at which electrolytes begin to decompose. At 55 degrees Celsius and above, conventional batteries that use electrolytes experience significant capacity reduction and swelling after 50 cycles.
The new battery, on the other hand, could sustain itself at 1 Ampere-hour capacity even after 200 cycles without generating gas and demonstrated enhanced safety and durability standards.
While elaborating on the usefulness of the scientific discovery, Professor Soojin Park of POSTECH said:
“This achievement in stability and commercial viability is poised to be a breakthrough in the electric vehicle industry. We hope this advancement will greatly benefit not only electric vehicles but also a wide range of other applications that rely on lithium-ion batteries.”
In the following segments, we will briefly look into some such applications of lithium-ion batteries.
The Application of Safe Lithium Batteries
Although they have recently gained attention for their use in electric vehicles, lithium-ion batteries are also safely utilized in a wide range of other applications. Several of these applications are integral parts of our daily lives, demanding commercial viability and strength. For instance, rechargeable lithium batteries are common in pacemakers and need to serve the device for a typical lifespan of seven to eight years while keeping their weight under 30 grams.
Digital cameras, particularly DSLRs, rely on lithium-ion batteries for their compact size and high power capacity, which deliver superior performance compared to other battery types. Similarly, digital assistants, smartphones, and laptops depend on these safe and reliable batteries for their durability, high energy density, lightweight construction, easy charging, and low-cost maintenance.
Moreover, small Li-ion batteries with a 3-volt capacity are used in devices as small as watches, which can last up to a decade. These batteries also power mobility solutions like personal scooters, golf carts, and trolleys, thanks to their ability to efficiently store and release electric charge. This capability makes them ideal for applications such as UPS systems, emergency power backups, and solar energy storage. Additionally, they are increasingly used in emerging fields like marine and leisure vehicles, as well as portable medical devices designed for wearability.
The increasing adoption of lithium batteries has driven a rise in their production and manufacturing. However, it’s crucial that these processes are as safe and viable as the batteries themselves. This concern is underscored by the recent tragic fire at a South Korean lithium battery facility, which resulted in the deaths of 22 workers.
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Fire at a South Korean Lithium Battery Facility
On June 24th, a devastating fire broke out at a lithium battery factory in South Korea, caused by multiple battery explosions, resulting in the death of 22 workers. The facility, operated by the primary battery manufacturer Aricell, is located in Hwaseong, an industrial area southwest of Seoul.
Shortly after the fire started, toxic gas quickly spread throughout the factory, which was storing up to 35,000 batteries at the time. Explaining the possible reason why the fire became as fatal as it did, Kim Jae-ho, a Fire and Disaster Prevention professor at Daejeon University, had the following to say:
“Battery materials such as nickel are easily flammable. So often, there is not enough time to respond, compared to a fire caused by other materials.”
The experts also pointed towards the fact that the casualty was higher because of the toxic materials used and not so much because of the burns.
Are Such Instances Preventable?
One must always be careful when dealing with lithium-ion batteries, as they have the highest volumetric energy density among energy storage devices. The Occupational Safety and Health Administration (OSHA) has published detailed instructions on preventing fire and explosion injuries from small and wearable lithium battery-powered devices.
The Massachusetts Institute of Technology, one of the most revered technology education institutes in the world, has also published Lithium-Ion Safety Guidance. According to their instructions, any working area that handles these batteries must have surfaces made of nonconductive and fireproof materials.
If one must work on a conductive surface, it is recommended to cover it with an insulating material. Additionally, the area should be free of flammable or combustible materials such as wood tables, carpets, gasoline, or sharp objects that could puncture the insulating sleeve on cells. The best working temperatures are between 15 and 35 degrees Celsius, and the ambient temperature should never exceed 60 degrees.
Proper storage plays a critical role in reducing the risk of fire and explosion. The report links many lithium-ion battery fires to inadequate storage areas. To maintain the highest safety standards, the storage area must consider factors such as cell design, chemistry, temperature, state of charge, and length of the storage period.
Battery manufacturing units must adopt stringent security measures, as fires in lithium battery facilities can be catastrophic not only due to the fire itself but also because of the resulting toxicity.
While security in manufacturing can be continually improved, batteries must also be inherently safe. Some companies have been steadily investing in the production of safe lithium batteries. In the coming segments, we will examine such companies.
#1. Panasonic Energy’s Lithium-ion Batteries
Panasonic is dedicated to ensuring battery safety as battery capacities grow and focuses on developing advanced battery materials, refining processes, and creating control technologies to guarantee safe and reliable battery use.
Its batteries have a high level of temperature-withstanding capability, as the risk of explosion rises when batteries are heated above 100 degrees Celsius. However, Panasonic recognizes that stacking or jumbling batteries may cause external short circuits, heat generation, fire, or explosion.
The company follows strict handling and storage guidelines, not allowing battery terminals to contact each other or other metals during packing. It uses strong packaging material to protect the goods from vibration, impact, dropping, and stacking during transportation. Panasonic also strictly recommends storing batteries at room temperature and charging them to about 30-50% capacity.
It produces a range of lithium battery products, including cylindrical batteries, prismatic batteries, pouch-type batteries, and pin-type batteries.
According to its latest available integrated report for the group, the company registered a sales revenue of 8,378.9 billion yen in 2023.
#2. LG Energy Solutions
LG Energy Solutions is another leading global brand that works under well-laid-out guidelines for its Li-ion battery pack manufacturing. It prohibits the use of Lithium-ion Battery Cells that have experienced any dropping for pack manufacturing.
To prevent electrical shorting, Lithium-ion Battery Cells should be kept away from metal objects and handled in environments that prevent damage or contamination.
Moreover, welding should not be conducted directly on the surface of Lithium-ion Battery Cells, and the cells should not be exposed to intensive heat or pressure during the welding process.
In 2023, LG registered a sales volume of 84,228 bn KRW, which was an incremental increase from 2022’s 83,467 bn KRW but a significant increase from the 73,908 bn KRW of 2021.
Lithium-ion Battery Safety Concerns: A Comprehensive Review
Research that extensively investigated Li-ion battery safety concerns pointed to several potential issues that could emerge as a threat or pose a risk.
Thermal runaways, which are among the most harmful safety issues in Li-ion batteries, arise from side reactions. These reactions can occur within the electrolyte, between the cathode and anode, and at the interfaces on electrode surfaces and Li plating. Such runaways are often triggered by mechanical, thermal, or electrical abuse.
Mechanical abuse can lead to safety issues in Li-ion batteries, just as electrical abuse can compromise their integrity. Similarly, thermal abuse, where a battery undergoes thermal shock or reaches excessively high temperatures, also poses significant risks.
The research also outlines strategies for improving safety, both internally and externally. A crucial element for enhancing Li-ion battery (LIB) safety is a well-engineered built-in cooling system. Additionally, maintaining the right balance among cells is essential; this involves measuring and comparing the voltages, capacities, or State of Charges (SOCs) of all cells after each charging cycle.
Manufacturers can follow several frameworks to ensure the safety of production. In fact, a host of countries have already published such standards, including the Chinese Standard, the Society of Automotive Engineers (SAE) standard, the International Electrotechnical Commission (IEC) standard, the United Nations (UN) standard, the Japanese Industrial Standard (JIS), and more.
Overall, we live in a time dominated by electronic gadgets, leading to an ever-increasing reliance on lithium batteries. As we pursue greater efficiency and speed in our technologies, we must ensure that safety remains a priority. The recent mishap in South Korea serves as a stark reminder of the importance of this balance, underscoring the need to prevent such unfortunate incidents in the future.
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