Chemitox, Inc. Launches Contract Testing Service for "Thermal Propagation Test" of Lithium-Ion Batteries

■ Background and Purpose of Introducing the Thermal Propagation Test

Generally, battery packs composed of multiple cells are protected from abnormalities such as overcharging and over-discharging by a BMS (Battery Management System). However, should a thermal runaway occur even once due to internal factors (e.g., internal short circuit caused by minute foreign material contamination), electrical control by the system becomes extremely difficult.

In the worst-case scenario of such an "uncontrollable single-cell runaway," whether the event spreads to adjacent cells (thermal propagation) becomes the single largest factor determining the scale of a fire and the damage to the entire system.

With the proliferation of EVs, international regulations (such as UN GTR No. 20 and GB 38031) strictly mandate not only the safety of individual cells but also "fire spread prevention" and "ensuring occupant evacuation time" at the vehicle pack level. Furthermore, this test is required by JIS C 8715-2 (compliant with IEC 62619), the safety standard for industrial lithium-ion batteries, to ensure the safety of the entire system. It is also regarded as a critical supplier responsibility to protect product safety in applications like power tools and portable power stations.

In response to these market needs, Chemitox will provide a thermal propagation test service that offers empirical data to prevent catastrophic large-scale fires.

■ Overview and Method of the Thermal Propagation Test

In this test, one cell (the trigger cell) within a battery pack or system is intentionally forced into thermal runaway to evaluate the thermal propagation to adjacent cells or modules.

To trigger the thermal runaway, the following methods are used, tailored to the customer's product specifications and standards:

- **Heater Heating (External Heating):** Induces thermal runaway by applying external heat.

- **Nail Penetration (Internal Shorting):** Causes a physical internal short circuit by penetrating the cell with a metal nail.

- **Overcharging (Electrical Abuse):** Induces a chemical runaway by applying a voltage higher than specified. *Not applicable to cylindrical cells that employ a PTC device or CID.

■ This Service is Recommended for the Following Customers

Chemitox's thermal propagation test can be utilized by a wide range of businesses involved with batteries.

- **Manufacturers of products equipped with multi-cell battery packs** (e.g., power tools, service robots, drones, portable power stations, commercial cleaning equipment)

- **Manufacturers of industrial energy storage systems and large mobility solutions** (e.g., grid-connected storage batteries, UPS, electric forklifts, EVs)

- **Battery pack and module assembly manufacturers** (companies that procure cells and integrate them into packs with their own BMS and cooling systems)

- **Importers and distributors of battery packs and systems** (trading companies and agencies that import and sell battery packs manufactured to overseas standards for the Japanese domestic market)

- **Suppliers of new materials for batteries** (material and chemical manufacturers developing flame-retardant materials, insulation sheets, cooling components, etc.)

Through this test, Chemitox will strongly support our customers' product safety evaluations and contribute to the proliferation of safer lithium-ion battery products. For details about the test or for consultations, please feel free to contact us via our website or the responsible contact person.

### [Contact for this matter]

Chemitox, Inc. Hokuto LiB Testing Center Hitoshi Watanabe (h-watanabe@chemitox.co.jp) Kiyohiko Sakamoto (k-sakamoto@chemitox.co.jp) Phone: +81-551-45-6133 Website URL: https://www.chemitox.co.jp

Hokuto LiB Testing Center

Location: 2966-8 Yanagisawa, Mukawa-cho, Hokuto-shi, Yamanashi Main Business: Safety testing, performance evaluation testing, etc., for lithium-ion batteries.

About Chemitox, Inc.

Chemitox, Inc. is an independent testing laboratory that provides testing, evaluation, and certification services for electronic devices, materials, and energy-related products. Through testing based on domestic and international standards, we contribute to ensuring the safety and reliability of products.

[Company Overview]

Name: Chemitox, Inc. Representative: Koichi Nakayama, Representative Director & CEO Location: 1-14-18 Kami-ikedai, Ota-ku, Tokyo Established: September 3, 1975 Capital: 98 million JPY Main Business: - Safety and reliability evaluation of lithium-ion batteries - Safety and reliability evaluation of solar cells - Research and development of all-solid-state batteries - Testing and evaluation of power devices - Evaluation of various properties of polymer materials, such as flammability, heat resistance, and mechanical properties - Environmental analysis of hazardous chemical substances, failure analysis and reliability testing of printed circuit boards - Consulting for acquiring overseas certifications such as UL certification - Biodegradability testing and support for obtaining biodegradability certification - Implementation of tests based on overseas standards for railway vehicles, aircraft, building materials, water-related products, food contact materials, etc., and consulting for standard compliance - Support for obtaining recycled material certification - Interpretation and translation services Website: https://www.chemitox.co.jp/