Thermal runaway, or thermal drift in Italian, is a major safety concern for batteries, particularly those used in electric vehicles and E-Mobility.
This is an uncontrollable process of heating that can lead to serious consequences, such as fire or explosion, due to excessive heat buildup inside the battery. Understanding the causes and dynamics of thermal runaway is critical to 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 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.
Stages of Thermal runaway progress
There are 3 stages of thermal runaway progress:
- Venting;
- Thermal Runaway;
- Propagation.
Although the thermal runaway becomes uncontrollable from 300°C, already around 100°C, as the components degrade, the exothermic reaction begins.
The temperatures to which an electric car battery that catches fire are around 700-1,000°C.
The consequences for the safety of EV batteries.
In the context of electric vehicles, thermal runaway is a serious risk. Not only for passenger safety, but also for serious traffic accidents and infrastructure damage.
Not to mention that the consequences may also come to harm the very image of the electric car brand.
Safe management of EV batteries is therefore critical to prevent thermal runaway. Research and development of safer battery technologies, thermal management systems, and improved safety protocols are all needed to mitigate this risk.
However, current regulations on battery safety are relatively nonspecific. The UN ECE GTR 20 standard, for example, requires only that passengers have 5 minutes to evacuate the vehicle in the event of a thermal runaway.
This time frame may not be sufficient in certain situations, such as if the electric car is on a highway. Under such circumstances, smoke invading the passenger compartment could hinder evacuation and cause serious intoxication.
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 that it could stop the flame in less than 15 seconds.
Mascherpa’s solutions
The electric vehicle revolution requires innovations in battery designs, addressing consumer anxieties related to range, as well as concerns about cost and safety. Electric batteries must provide safe and reliable performance throughout their service life.
There is variety in battery designs, marked by the choice of cell type-cylindrical, pouch, or prismatic- adopted by manufacturers. Challenges for OEMs and Tier 1s include reducing costs and optimizing performance, as well as ensuring safety, reliability, and flawless integration with the vehicle structure.
Mascherpa supports vehicle manufacturers in navigating these complexities by providing advanced thermal management materials, adhesives, sealants, and coating technologies, all designed to overcome industry challenges.
In conclusion we can say:
- thermal management and safety solutions are critical in battery design;
- thermal solutions provide and improved battery performance and life cycle;
- have passed abuse tests in several battery designs and improve safety performance;
- Have excellent compatibility with a wide range of building materials;
- can also be used with advantage in direct cooling of battery packs and inverters.
Each battery has an applicable thermal management model, but the issue of TCO remains critical for high-performance solutions.
The solutions are in the Mascherpa portfolio and are supported by specific programs, such as:
In a rapidly evolving market such as electric vehicles, battery pack protection and thermal runaway management are crucial.
In addition to boasting outstanding performance and broad compatibility with building materials, we are keen to emphasize our ongoing commitment to standing by our customers.
For more information, contact our team of experts who are fully available to provide you with technical support and personalized advice
