Three Ways to Protect Vehicle from LiB Thermal Runaway: Part 1 of 2

With the increasing adoption of BEVs, the development aimed at improving the performance of LiBs is progressing globally. Particularly, the improvement of "battery capacity," which determines how far a vehicle can travel on a single charge, and "safety enhancement" are critical issues.

One of the main components of LiBs, the electrolyte, often uses liquid flammable substances. When external impacts on the LiB cause a short circuit, a large current flows instantaneously within the LiB, generating a significant amount of heat. This "thermal runaway" can lead to the ignition of the BEV. In fact, there have been reports of BEV fire accidents worldwide due to thermal runaway in LiBs.

Given this background, how to prevent the thermal runaway of LiBs is one of the most crucial factors in designing BEVs.

Three Approaches to Prevent Thermal Runaway

There are several approaches to prevent thermal runaway in LiBs. For example, operating a battery management system to prevent overcharging and over-discharging, thereby managing the battery temperature, is one approach. Another effective measure is the structural design that manages thermal energy by dissipating the heat generated inside the battery to the outside. These comprehensive measures enable advanced design to prevent BEV fire accidents.

Even with these measures, in the event that thermal runaway does occur due to a strong external impact, it is crucial to consider how to delay ignition, weaken the intensity of the fire, and prevent the spread of flames as preparedness for an emergency.

China's GB 38031-2020 standard mainly stipulates various safety aspects (thermal, mechanical, electrical, and functional) of battery systems. It requires that in the event of thermal runaway, the battery should not ignite within five minutes after the battery management system issues a warning, ensuring that passengers have enough time to escape.

Thermal Runaway Prevention Using Formable Fireproof Insulation Sheets

To address such thermal runaway incidents, NAGASE is accelerating its collaboration with Boomrun to improve the safety of BEVs. The company offers a diverse and high-performance product lineup aimed at enhancing BEV safety from multiple angles. In this and the following articles, we will introduce three of their products.

Products developed in collaboration wtih Boomrun to address thermal runaway

Fireproof Insulation Sheet with High Fire Resistance (Product Name: MK Sheet)

The Fireproof Insulation Sheet with High Fire Resistance (Product Name: MK Sheet) is composed of silicone and glass fibers, designed to cover battery modules and entire battery cells. Its silicone-based soft material allows efficient molding to fit the target object. It has obtained certification according to GB38031 and passed fire testing (1,500℃ for 30 minutes at 1 mm thickness). This product has already been installed in actual vehicles in China, demonstrating its effectiveness.

The MK Sheet is not only effective in providing fire resistance but also offers excellent thermal insulation properties. The combination of silicone and glass fibers ensures that the sheet can withstand high temperatures without degrading, making it an ideal solution for protecting battery components. Additionally, the flexibility of the silicone material allows for easy installation and ensures a snug fit around various shapes and sizes of battery modules.

Furthermore, the MK Sheet has been rigorously tested to meet international safety standards, ensuring its reliability and performance in real-world applications. The successful implementation of this product in vehicles across China highlights its practical benefits and the trust that manufacturers have placed in its capabilities. As electric vehicles become more prevalent, the need for robust fire protection solutions like the MK Sheet will continue to grow, making it a crucial component in the advancement of safe and efficient battery technologies.

Summary of Part One and Preview of Part Two

In this part, we have introduced approaches to prevent LiB thermal runaway and provided details of one solution: the thermal insulation sheet. In Part Two, we will further introduce thermal runaway solutions, specifically in-cell insulation material and humidity control material.

If you have any concerns regarding the safety of LiB or seek expert guidance on its improvement, please contact NAGASE.