Assess Coin Cell Battery Safety and Thermal Stability with New Technology

How the Coin Cell DSC facilitates full-cell thermal stability testing without teardown

Morgan Ulrich | Hang Lau
June 16, 2026

Assess Coin Cell Battery Safety and Thermal Stability with New Technology

Today’s battery innovations are pushing boundaries with higher energy density, higher power, and longer run time. However, these advancements can come with serious safety risks. Measuring battery safety and stability early in the development cycle is critical to ensure that new designs are successful before moving to scale up production of complete batteries.

Measuring Battery Thermal Stability

Thermal stability refers to a material’s ability to resist degradation when exposed to heat. Luckily for battery developers, there is a well-established materials science technique for measuring heat flow: Differential Scanning Calorimetry (DSC). DSC instruments from the Waters Materials Sciences Division have been widely used in polymer, pharmaceutical, and other material science research since the 1970s.

DSC is used by battery researchers and developers to study thermal stability and decomposition in battery materials, but a traditional DSC is not designed for battery testing. The current workflow involves taking apart a battery cell to test individual materials on a DSC, but testing materials separately may not reveal the full extent of their thermal stability or cross reactions. Safety tests of complete cells are delayed until later in development, often leading to costly and time-consuming corrections.

A Breakthrough Solution for Battery Safety Testing

The Waters TA Instruments™ Coin Cell Differential Scanning Calorimeter enables battery researchers and developers to directly assess whole coin cells’ safety and performance without teardown. Now, whole-cell testing can take place earlier in development. These tests can guide battery development by identifying reactions that may lead to self-heating or thermal runaway. Then, developers can correlate this data with late-stage safety testing for a full picture of battery stability.

Batteries can degrade due to temperature changes or overcharge/overdischarge, so the Coin Cell DSC is designed to capture reaction triggers and the resulting thermal events. Its fit-for-purpose coin cell capsule captures the complete heat flow signal throughout the entire temperature range, revealing how temperature changes can lead to reactions within the battery. An integrated wire connection provides voltage monitoring during cell thermal failure, allowing you to correlate thermal processes with electrochemical data.

The following experiments show key battery safety measurements obtained from the Coin Cell DSC.

Thermal Runaway Onset Temperature

Thermal runaway occurs when a critical high temperature triggers exothermic reactions that lead to further temperature increases. Identifying the onset temperature and resulting reactions is critical for predicting failure and designing safer batteries.

In the following example, an NMC coin cell battery was ramped to 600 °C, revealing four steps of the reaction:

Onset temperature of irreversible cell decomposition
Separator melting and coin cell gasket melting that allow gas venting for evolved gas analysis
Thermal decomposition and cross reaction of electrolyte and active materials
Thermal degradation of gasket and high temp reaction with active materials

Figure 1: Temperature ramp to 600 °C of an NMC coin cell battery

This temperature ramp of a complete coin cell battery was facilitated by the Coin Cell DSC’s highly sensitive sensor. This technology offers more accurate onset temperature analysis and supports characterization of complex reaction mechanisms.

Battery Short Circuit Analysis

Identifying exactly when a battery short circuits and loses its functionality is critical for engineering and design. Voltage monitoring measures the battery’s state-of-charge and detects electrochemical signals when an internal short circuit or voltage drop occurs, correlating reactions that lead to the changes.

The following figure shows when a short circuit starts to occur. This sharp drop of voltage indicates a short circuit, followed by the cell completely failing and voltage dropping to 0 V. Pinpointing a battery short circuit helps battery developers determine if their design is safe for typical use conditions or needs to be redesigned to withstand higher temperatures. The insert plot showed a reaction heat flow onset around 119 °C that led to a decrease in voltage at 130 °C, revealing early signs of degradation.

Figure 2: Voltage monitoring paired with heat flow measurement to pinpoint a short circuit.

Versatility in Battery Safety Testing

In addition to identifying short circuits and thermal runaway onset temperatures as shown above, battery developers also need to understand the reactions and off gas composition if a battery exceeds safety thresholds. Off-gas analysis reveals the gases released during a reaction, such as carbon dioxide, oxygen, hydrocarbon, and other decomposition products. Identifying these gases is essential for determining if a battery poses greater safety and fire risks when it fails.

And finally, all of this data is only as powerful as your ability to analyze it. The Coin Cell DSC’s TRIOS software delivers exceptional user experience in instrument control, data analysis, and reporting. Built-in templates facilitate common coin cell safety testing methods. TRIOS also efficiently combines data from different modes of testing, including voltage monitoring, off-gas analysis, and heat flow measurements.

Learn more about the Coin Cell DSC and contact Waters Materials Sciences’ battery experts for more information.