Are Lithium-Ion Batteries Safe? A Basic Guide 

Are Lithium-Ion Batteries Safe for a work environment? The answer is simple: they can be under the right circumstances. 

In this Power Grid Podcast episode, we delve into the world of lithium-ion battery safety, exploring its inner workings, potential risks, and the evolution of safety features that make it a reliable choice for critical power applications.

 

 

About Lithium-Ion Batteries

A wisp of smoke curls from your UPS battery cabinet. Fear grips you as you realize the lithium-ion batteries are on fire. Is this a common occurrence? 

What safety measures are in place to prevent such disasters? While lithium-ion batteries are a game-changer in power protection, their safety is a critical concern.

 

How Do Lithium-Ion Batteries Work?

Lithium-ion batteries are the powerhouse behind many modern devices, from smartphones and laptops to electric vehicles and uninterruptible power supplies (UPS). They offer superior energy density, longer lifespans, and faster charging times compared to traditional battery technologies.

 

The basic principle behind a lithium-ion battery involves the movement of lithium ions between two electrodes – the anode and the cathode – through a separator. This separator is crucial for preventing a short circuit, which can occur when the anode and cathode come into direct contact. 

During charging and discharging, lithium ions shuttle between the electrodes, creating an electrical current.

 

Potential for Fire:

While lithium-ion batteries offer impressive performance, they also pose a potential fire risk.  If the separator is damaged or compromised, the anode and cathode can come into contact, leading to a short circuit. 

This short circuit generates heat, which can trigger a chain reaction called thermal runaway. In thermal runaway, the battery’s internal temperature rises rapidly, leading to the release of flammable gases and, potentially, a fire.

 

Lithium-Ion Battery Safety: The Evolution of a Technology

To understand the current state of lithium-ion battery safety, it’s helpful to look back at the evolution of battery technology.

Early Days of Valve-Regulated Lead-Acid (VRLA) Batteries: 

Before lithium-ion batteries became prevalent, valve-regulated lead-acid (VRLA) batteries were the standard for UPS systems. However, VRLA batteries had limitations, including susceptibility to short circuits and swelling due to off-gassing. 

These issues raised safety concerns and highlighted the need for more advanced battery technologies.

 

The Rise of Modular Batteries

The introduction of modular battery design marked a significant step forward in battery safety. These modular systems incorporated basic safety features like temperature and smoke sensors, allowing for easier maintenance and early detection of potential problems.

 

Lithium-Ion Batteries

A Game Changer with Growing Pains: The arrival of lithium-ion batteries revolutionized the power protection industry with their superior performance. However, the initial iterations of lithium-ion batteries faced challenges in ensuring safety. 

Their performance advancements outpaced the development of adequate safety measures, leading to concerns about thermal runaway and fires.

 

Modern Lithium-Ion Batteries: Safety Takes Center Stage

In recent years, significant advancements have been made in lithium-ion battery safety. Manufacturers have focused on developing robust safety features at the cell, module, and battery rack levels to mitigate the risk of thermal runaway and fire. 

These features include advanced battery management systems, thermal monitoring, and protective mechanisms to prevent overcharging and short circuits.

UL Safety Standards for Lithium-Ion Batteries

Underwriters Laboratories (UL), a leading safety science organization, has developed several standards to ensure the safety of lithium-ion batteries in various applications.

• UL 1778: This standard covers the safety of uninterruptible power supplies (UPS), including the lithium-ion batteries used within them. It addresses electrical, thermal, and mechanical safety requirements to ensure the safe operation of UPS systems.
• UL 1973: This standard specifically focuses on lithium-ion battery systems for UPS applications. It outlines requirements for battery construction, performance, and safety, with a particular emphasis on preventing thermal runaway and fire hazards.
• UL 9540A: This standard is a test method for evaluating fire propagation in battery energy storage systems. It helps manufacturers assess the fire safety of their lithium-ion battery systems and identify potential areas for improvement.

 

Multi-Layered Safety Approach for Lithium-Ion Battery Cabinets

The safety of lithium-ion batteries in power protection applications is not left to chance. A multi-layered approach is employed to ensure the safety of both the batteries themselves and the surrounding environment. 

Let’s explore these layers of protection, from the cabinet-level down to the individual cells.

 

Cabinet-Level Protection

Switchgear and Rack Battery Management System (BMS): At the heart of lithium-ion battery safety lies the Battery Management System (BMS). 

This sophisticated system acts as the brain of the battery cabinet, continuously monitoring and controlling various parameters such as voltage, current, and temperature. It can detect anomalies like overcharging or overheating and take corrective action, such as adjusting charging rates or disconnecting the battery from the UPS if necessary. 

This real-time monitoring and control is crucial for preventing thermal runaway and ensuring the safe operation of the battery system.

 

Secure Doors and Covers

Lithium-ion battery cabinets are equipped with robust doors and covers that serve as physical barriers. These barriers restrict unauthorized access, protecting personnel from electrical hazards and preventing accidental contact with the batteries.

Seismic Kits: In regions prone to earthquakes, battery cabinets are often equipped with seismic kits. These kits secure the cabinets to the floor or wall, preventing them from tipping over or sustaining damage during seismic events.

 

Cell-Level Protection

• Internal Fuses: Even at the individual cell level, safety is a priority. Each lithium-ion cell within a module has its own internal fuse for added protection. This fuse prevents overcharging and external short circuits, safeguarding the cell from damage and potential thermal runaway.
• Anode and Separator Design: The anode and cathode of a lithium-ion battery are separated by a thin layer of material called a separator. The design of the anode and separator is critical for preventing internal short circuits, which are a leading cause of lithium-ion battery fires. Modern lithium-ion batteries utilize advanced separator materials and designs to enhance safety and prevent these shorts.
• Overcharging Protection: Lithium-ion batteries are equipped with voltage and temperature sensors that monitor each individual cell. If a cell’s voltage or temperature exceeds safe limits, the sensors can trigger a shutdown of the module or even the entire cabinet to prevent overcharging, a major contributor to thermal runaway.

 

Communication and Monitoring

Each battery module is equipped with a communication card that relays critical information to the Battery Management System (BMS). This real-time data allows the BMS to monitor the health and performance of each cell, enabling early detection of potential issues and proactive measures to prevent safety hazards.

Lithium-ion battery systems employ a multi-tiered BMS architecture. There’s a BMS at the module level, another at the rack level, and a master BMS integrated into the UPS system.

 

 

Confidence in Lithium-Ion Battery Safety

The evolution of lithium-ion battery technology has led to significant advancements in safety features, making them a reliable and secure choice for critical power protection applications. The multi-layered safety approach, from the cabinet level down to the individual cells, ensures that potential risks are mitigated, and your facility remains protected.

If you’re considering lithium-ion batteries for your UPS system or other power protection needs, Power Protection Products (P3) can provide expert guidance and support. 

 

Contact us today to learn more about our lithium-ion battery solutions and how we can help you design and implement a safe and reliable power protection system for your facility. Remember, confidence in your power protection begins with choosing the right technology and understanding the safety measures in place.