Hyundai Mobis develops battery system with built-in fire extinguishing feature

Technology to prevent thermal runaway in electric vehicles is being advanced. Hyundai Mobis has recently announced that it had succeeded in developing a new technology that can extinguish a fire immediately by spraying a fire extinguishing agent when a battery cell catches fire. This is the first technology that can prevent thermal runaway by preventing heat from being transferred to adjacent cells.

Hyundai Mobis has designed the system to go beyond simply delaying thermal runaway using heat-resistant materials, and prevent it from occurring in the first place. Major countries such as Europe, China and India have mandated that thermal runaway be delayed for at least five minutes after the initial ignition of the battery cell, while some countries are tightening their regulations to prevent thermal transfer from occurring in the first place. Accordingly, Hyundai Mobis’ battery system assembly (BSA) with cell-level fire extinguishing feature is expected to be in the spotlight as next-generation safety technology in the global market.

The BSA developed by Hyundai Mobis consists of a battery management system (BMS), hardware consisting of a fire extinguishing device and battery case, and software logic that controls them.

Based on the real-time data collected by the sensors, it analyzes the temperature and voltage of the battery and the pressure inside the battery system to determine any abnormalities. It then sets the location where the extinguishing agent will be sprayed and commands the fire extinguishing device to operate.

The software is designed to make quick and accurate decisions to deal with any physical changes that may occur in the battery system. Hyundai Mobis’ highly reliable decision logic features multiple safety devices and a redundant algorithm structure.

The battery system is equipped with a fire extinguishing agent that is five times the capacity of a 3.3 kilograms home fire extinguisher. This agent is a substance with excellent cooling, insulation, and permeability properties, and is harmless to both the environment and human body.  

HYUNDAI MOBIS APPLIES FOR THREE PATENTS 

A model of the battery system equipped with fire extinguishing agents developed by Hyundai Mobis.

Hyundai Mobis states that it applied for a total of three domestic and international patents, including a battery case and a fire extinguishing device. These also include piping for fire extinguishing agents and design that enables high-pressure spraying.

“As large electric vehicles with improved driving range appear, the safety standards for battery systems are becoming more stringent,” said Park Yong Jun, Vice-President, Battery System R&D Group, Hyundai Mobis. “We will integrate hardware and software to develop advanced battery systems that meet and exceed global standards, and introduce them to the global market.”    

A comparison test of the heat dissipation performance between Hyundai Mobis' 'Pulsating Heat Pipe' for battery cell cooling and a standard aluminium cooling plate revealed a temperature difference of nearly 20 degrees.

Meanwhile, Hyundai Mobis has also recently developed a new material that prevents battery overheating (pictured above), and is currently focusing on commercializing it. This material, called pulsating heat pipe, is composed of aluminium alloy and refrigerant, and placing it between battery cells can lower the internal temperature of the battery system. It is expected to be applied as a thermal management system that can manage heat reliably even during rapid charging.

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