Lithium Ion Battery Rack Monitoring



Lithium ion (Li-ion) batteries are becoming increasingly popular. They provide a solution to many of the energy challenges the world faces today. They are typically used in applications such as data centres that require uninterruptible power supply. Lithium ion battery racks contain as many batteries as required to meet the power requirements of the application – this can range from single racks with a small number of batteries to multiple racks that take up an entire dedicated room.

Battery fires can be devastating to any business. Therefore, it is imperative that suitable and reliable fire detection systems are in place to catch fire in its early stages so it can be dealt with before serious damage occurs and lives are put at risk.

What are the Risks?

Lithium ion technology is inherently flammable leaving many organisations concerned about the safety of Li-ion batteries. If mistreated or damaged, Li-ion batteries can fail and  thermal runaway – a situation where an increase in temperature changes the conditions in a way that causes a further increase in temperature – can occur and start a fire within the battery rack.

What are the Challenges?

There are several stages to Lithium ion battery failure:

Typically, the first stage is battery abuse. This can be anything from thermal abuse where the battery is allowed to overheat, electrical abuse such as when the battery is overcharged and mechanical abuse.
The second stage is off-gas. This occurs when a battery begins to fail. Electrolytes break down and generate gas which is released from the cell in an off-gas event. This occurs significantly before thermal runaway – a situation where an increase in temperature changes the conditions in a way that causes a further increase in temperature.
Smoke Generation
Smoke generation occurs once thermal runaway has started and catastrophic failure is imminent.
Fire often occurs at the same time as smoke generation and can have devastating consequences. Often, by the time a battery has reached this stage, stopping it from spreading to other batteries in the rack is almost impossible.

Traditional fire detection systems are unable to detect a fire before there is any smoke. By this point, it is likely that flames are already present and are causing neighbouring batteries to ignite in a catastrophic chain of events. At this point, the chances of dealing with the fire before serious harm is done are slim.

What is the Solution?

The Li-ion Tamer rack monitor from Xtralis is a gas monitor detection solution that provides an early and reliable warning of battery fires. It provides the earliest possible warning of Li-ion battery failure by detecting off-gas events that occur early on in the failure of Li-ion batteries. This means that failures can be detected before the smoke and fire stages, allowing any threats of fire or thermal runaway to be assessed and mitigated before any significant damage is caused.

The Li-ion Tamer is a cost-effective plug-and-play solution that is easy to install and consists of just two components: off-gas sensors and controllers. Sensors can be placed where necessary to provide a truly versatile solution and pinpoint addressability allows targeted response and improved situational awareness.

Nuisance alarms are kept to a minimum thanks to sophisticated referencing techniques and calibration-free sensors and extended sensor life while simplified bump testing keeps maintenance costs low.

Key Features

  • Early warning of Lithium-ion battery failures
  • Single cell failure detection without electrical or mechanical contact of cells
  • Extended product lifetime
  • Calibration-free
  • Highly reliable output signal
  • Low power consumption
  • Compatible with all Lithium-ion battery form factors and chemistries
  • Easy installation
  • Independent and redundant perspective on battery health
  • Auto diagnostic capabilities
  • Reduction/removal of false positive signals
  • Multiple communication protocols including digital outputs and Modbus serial communication

System Configuration

At the heart of the Li-ion Tamer battery rack monitor is the Li-ion Tamer controller. Monitoring sensors are installed at the battery racks to monitor off-gas events and connected to the controller using RJ45 ethernet cables. Reference sensors are installed outside of the battery rack to monitor the ambient environment through air inlets to cancel common mode signals. The controller then aggregates the signals from both sets of sensors to provide reliable detection of off-gas events while mitigating nuisance alarms.

Sensors are calibration-free and can easily be verified with a bump test. To confirm operation, sensors can be activated with a bottle of battery off-gassing compounds (diethyl carbonate).