Lithium-ion batteries – do they pose a safety hazard

As UK building owners turn more to solar power as a means to reduce their carbon footprints and cut energy costs, lithium-ion batteries have equally become the go-to solution to store energy when the sun is no longer shining. However, while these batteries offer impressive energy density and efficiency, there is growing concern about their safety in domestic and commercial settings writes Phil Wiltshire, operations director at Pensdown, the electrical people.

Lithium-ion batteries are favoured for their high energy density, relatively low maintenance, and long service life compared to older battery technologies, but these same characteristics can also pose significant risks if not managed correctly. While manufacturers have improved the safety features of these batteries over the years, there have been incidents in residential and commercial installations, which would indicate that potential dangers still exist, particularly in situations when installations are not made correctly.

At their core, lithium-ion batteries work by shuttling lithium ions between a positive electrode (cathode) and a negative electrode (anode) through an electrolyte. This process stores and releases electrical energy as needed. Under ideal conditions, this cycle is safe and efficient. However, lithium-ion batteries are sensitive to a variety of stress factors including overcharging, deep discharging, extreme temperatures, incorrect installation, as already mentioned and physical damage.

Any of these factors can lead to a phenomenon known as thermal runaway - a self-sustaining reaction that can cause fires or explosions. This has been seen many times in vehicles – and there have been reports, from different parts of the world, that they pose a risk for building owners and residents.

Thermal runaway occurs when the battery’s internal temperature rapidly increases, often triggered by a short circuit or physical damage. Once initiated, this reaction can spread from cell to cell, potentially leading to catastrophic failure. In the confined spaces of a building, where ventilation may be limited, the risks are further magnified.

While such events remain relatively rare compared to the number of installations, their consequences can be severe, both in terms of property damage and personal safety. It is also important to note that lithium-ion batteries remain one of the most efficient ways to store renewable energy. Any incidents are isolated cases that typically result from a combination of factors such as poor installation practices, inadequate maintenance, or inherent defects in the battery system. It should also be noted that while the market for home energy storage continues to grow, both manufacturers and regulatory bodies are taking significant steps to improve safety standards.

Better installation and maintenance standards

One of the key lessons learned from past incidents is the critical importance of proper installation. We at Pensdown strongly advocate that all home solar installations involving lithium-ion batteries should be carried out only by certified MCS accredited professionals who adhere to the latest industry standards. Regular maintenance checks, including thermal imaging and routine inspections, can also help identify early signs of battery degradation or malfunction. By addressing issues before they escalate, building owners can significantly reduce the risk of catastrophic failure.

Modern lithium-ion battery systems are increasingly being equipped with advanced battery management systems (BMS). These systems continuously monitor the state of the battery, including temperature, charge levels and internal resistance. In the event of any irregularities, the BMS can take corrective action - such as reducing the charge rate or shutting down the battery - to prevent thermal runaway. Ongoing research and development in BMS technology also promises to make these systems even more reliable, further mitigating potential hazards.

In addition to improving battery management, the integration of fire suppression technologies within battery enclosures is a promising development. Fire-resistant materials, automatic fire extinguishing systems and enhanced ventilation designs are being tested and implemented in new battery storage units. Such measures can help contain a fire if one were to occur, limiting damage and providing crucial time for emergency services to respond.

Governments and industry regulators are also playing a pivotal role in enhancing the safety of residential lithium-ion battery installations. Updated building codes and safety regulations are being developed to address the unique challenges posed by these systems. In many countries, new standards require rigorous testing of battery systems under extreme conditions, ensuring that only the safest technologies make it into the consumer market. As an accredited contractor we support these regulatory measures, recognising that a proactive approach to safety can prevent many potential incidents.

Despite the potential dangers, lithium-ion batteries are likely to remain a cornerstone of home energy storage for the foreseeable future. However, several trends and innovations are set to transform the technology and address current safety concerns.

Transition to safer batteries

Researchers are actively exploring alternative battery chemistries that could offer improved safety profiles. For instance, lithium iron phosphate (LiFePO4) batteries are known for their thermal stability and lower risk of thermal runaway. Although these batteries may not yet match the energy density of traditional lithium-ion cells, ongoing improvements could make them a viable option for residential storage.

Similarly, solid-state batteries, which use a solid electrolyte instead of a liquid one, promise significantly enhanced safety. By eliminating the volatile liquid electrolyte, these batteries could virtually eliminate the risk of leakage and fire. While solid-state technology is still in the developmental stage, its potential for safer, more durable energy storage is immense.

All this means that the future of home energy storage will likely be characterised by even greater integration with smart home systems. Advanced sensors and IoT (Internet of Things) technology will enable real-time monitoring of battery performance, environmental conditions, and usage patterns. This data can be used to predict potential issues before they become dangerous, allowing homeowners and service providers to take preventative action. Imagine a system that not only alerts you to an overheating battery but also schedules a maintenance visit automatically, a level of integration that could be a game-changer for residential and commercial safety.

Lithium-ion batteries have certainly revolutionised the way we store renewable energy, providing an efficient and sustainable solution for powering our homes with solar energy. However, as with any advanced technology, they come with inherent risks that must be managed.

All this means that the future of home energy storage looks promising, with new battery chemistries, enhanced management systems, smart integration and stronger regulatory oversight on the horizon. However, as the industry continues to evolve, it is essential that manufacturers, installers, regulators and consumers work together to ensure that this technology not only delivers on its promise of sustainability but does so without compromising safety.

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