Thermal runaway is a major safety concern for batteries, particularly those used in electric vehicles and e-mobility.
This is an uncontrollable heating process that can lead to serious consequences, such as fire or explosion, due to excessive heat build-up inside the battery. Understanding the causes and dynamics of thermal runaway is crucial for the development of safer battery technologies and the implementation of effective preventive measures.
What is thermal runaway
Thermal runaway is an autocatalytic process that occurs when a temperature rise in an electric battery cell leads to an out-of-control exothermic reaction. This phenomenon can lead to the release of harmful gases, fires, or even explosions. It is particularly relevant in lithium batteries, which are widely used for their high energy density and efficiency in electric vehicles and other energy applications.
Triggering mechanisms
Mechanisms that can trigger thermal runaway are varied and include:
- Overload: applying a voltage higher than rated can cause overheating and internal damage to the cell
- Short circuit: an internal or external short circuit can generate a sudden release of thermal energy, triggering the reaction
- Physical damage: mechanical impacts or penetrations can compromise the structural integrity of the cell, leading to dangerous reactions
- Manufacturing defects: anomalies during the manufacturing process can leave impurities or defects that increase the risk of thermal runaway.
Thermal runaway stages
There are 3 stages of thermal runaway advancement:
- Venting
- Thermal Runaway
- Propagation
Although the thermal runaway becomes uncontrollable from 300°C, already around 100°C, with the degradation of the components, the exothermic reaction begins.
The temperatures at which an electric car battery catches fire are around 700-1,000°C.
The safety consequences of E-batteries
In the context of electric vehicles, thermal runaway poses a serious risk Not only for the safety of passengers, but also for serious traffic accidents and damage to infrastructure.
Not to mention that the consequences can also damage the very image of the electric car brand.
Safe handling of EV batteries is therefore crucial to prevent thermal runaway Research and development of safer battery technologies, thermal management systems and improved safety protocols are all necessary to mitigate this risk.
However, current battery safety regulations are relatively non-specific The UN ECE GTR 20 standard, for example, only requires that passengers have five minutes to evacuate the vehicle in the event of a thermal runaway.
This time may not be sufficient in certain situations, such as if the electric car is on a motorway. In such circumstances, smoke invading the passenger compartment could hinder evacuation and cause serious poisoning.
However, there are promising technologies that can limit the damage caused by thermal runaway One example is an EV battery casing impregnated with SYLGARD, which in one test showed it could stop the flame in less than 15 seconds.
MD Poland solutions
The electric vehicle revolution requires innovations in battery designs, addressing consumer anxieties about range, as well as concerns about cost and safety Electric batteries must provide safe and reliable performance throughout their lifetime.
There is a variety in battery designs, marked by the choice of cell types – cylindrical, pouch, or prismatic – adopted by manufacturers Challenges for OEMs and Tier 1s include cost reduction and performance optimisation, as well as ensuring safety, reliability and flawless integration with the vehicle structure.
MD Poland supports vehicle manufacturers in navigating these complexities by providing advanced thermal management materials, adhesives, sealants and coating technologies, all designed to overcome the challenges of the industry.
In conclusion we can say that:
- Thermal management and safety solutions are critical in battery design
- Thermal solutions offer and improve battery performance and life cycle
- Have passed abuse tests in various battery designs and improve safety performance
- Have excellent compatibility with a wide range of construction materials; and
- Can also be used to advantage in direct cooling of battery packs and inverters
Each battery has an applicable thermal management model, but TCO remains a key issue for high performance solutions. The solutions are in the MD Poland portfolio and are supported by specific programmes, such as DOW with MobilityScience.
In a fast-moving market like electric vehicles, battery pack protection and thermal runaway management are crucial.
As well as boasting exceptional performance and broad compatibility with construction materials, we are keen to emphasise our ongoing commitment to our customers.
