Thermal Ramp (Abuse) Test
Thermal ramp is a type of thermal abuse test where a cell is heated to the point of failure. The purpose is to see how the cell responds to excessive heating and help quantify and understand the magnitude and effects of such a failure. It helps battery pack engineers determine the appropriate design specifications they need to make when designing a battery pack to prevent such a reaction from occurring and to minimize the effect should it occur.
Test Procedure:
- According to Sandia standard SAND2017-6925, the test should be conducted starting at normal operating temperature and 100% state of charge (SOC).
- The cell is wrapped in a layer of insulation after being fit with thermocouples and placed in a heating fixture.
- It is then heated at a rate of 2-5 °C/min (±0.5 °C/min).
- The test ends when one of the following conditions is met: the cell reaches 250°C and is held at that temperature for 15 minutes without any measured self-heating (dT/dt > 0.1°C/min) or the cell experiences a hazard safety level (HSL) of 5 or greater (cell catches fire).
- The cell should be monitored for at least 30 minutes after the test and if possible tested at lower SOCs to understand how the failure changes.
Standards Followed:
Sandia standard SAND2017-6925. Similar other standards are UL 1642, UN 38.3, IEC 62133, GBT 36276.
Equipment used:
Inhouse BSI setup to perform Thermal Ramp Test
Example Test :
A typical 18650 cylindrical cell was subjected to thermal characterization through a thermal ramp test. The test protocol for this test includes continuous monitoring of cell voltage and temperature throughout the test. Cell temperature and voltage vs. time is shown in the accompanying plot, with corresponding quantitative data summarized in the tables below.
Figure 1: Cell Temp & Voltage vs. Time plot
Example Test :
| Test Name | Wt. Loss (%) | Peak T(⁰C) | Over Cell T(⁰C) | Max. dT/dt (C/min) | Average Max Temp. At Voltage Drop (⁰C) | HSL | Description | ||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Cylindrical 18650 Cell | 56.9 |
|
86 | 181 | 205 | 5 | Top blew up with bang sound during thermal runaway. Aluminum electrode pieces came out as shown in video |
FAQ:
1. What is Battery Thermal Abuse Testing?
Battery thermal abuse testing is a safety test performed on batteries (especially lithium-ion batteries) to evaluate how they behave under extreme heat conditions that might occur during misuse, accidents, or external hazards. It is a type of abuse test where a battery is subjected to elevated temperatures beyond its normal operating range.
2. What is the purpose of thermal Abuse testing?
To check if the battery:
Undergoes thermal runaway (uncontrolled self-heating leading to fire/explosion).
Vents gases safely without ignition.
Maintains structural integrity or fails catastrophically.
3. What are the common standards used for battery thermal Abuse Testing?
Commonly used industry standards are UL 1642, UN 38.3, IEC 62133, SAE J2464, GBT 36276.
4. What are the typical criteria for success?
A battery “passes” if it does not explode or catch fire (venting without flame is often acceptable depending on the standard
5. Is Accelerating rate calorimetry same as thermal ramp test?
Although they sound similar, Accelerating Rate Calorimetry (ARC) and a thermal ramp test are not the same. Thermal Ramp test is a qualitative test (fire/no fire, explosion/no explosion, venting). Thermal Ramp is a regulatory safety abuse test. However, ARC provides Qualitative & Quantitative data (exothermic reaction onset, self-heating rate [dT/dt], pressure, heat release). ARC is more precise, provides detailed thermal runaway kinetics Used in battery design, material evaluation, and thermal modeling.
In simple terms
Thermal ramp tells us – Will this battery blow up if overheated?
ARC tells us – At what temperature does runaway start, how fast does it heat itself, and how much energy does it release?