from chemistry to pack
When one cell goes into thermal runaway, whether you end up with a contained event or a pack fire depends on what its neighbours experience, thermally and electrically. This post sets out the heat paths that published test work identifies, what that work does and does not quantify, and the electrical effects, which get less … Read more
The Venting and Physics of Thermal Runaway pages describe cell venting qualitatively: gas builds up inside the cell, a burst disc or crimped vent opens once a threshold pressure is reached, and hot gas and electrolyte aerosol are ejected. This post works through the same event quantitatively, how fast the gas actually leaves the cell … Read more
Why Certification Alone Won’t Save Us Introduction Lithium-ion batteries power modern life, from the phone in your pocket to the electric vehicle in your driveway to the grid-scale energy storage facility humming at the edge of town. With this ubiquity comes an uncomfortable truth: these systems store enormous energy in compact volumes, and when they … Read more
Lithium-ion batteries are the backbone of modern electric vehicles (EVs) and energy storage systems, but their high energy density comes with severe safety risks. The primary threat is thermal runaway (TR), an uncontrollable, self-sustaining chain reaction where a battery’s heat generation vastly exceeds its ability to dissipate heat. During TR, internal temperatures can rapidly escalate … Read more
When a lithium-ion battery cell experiences thermal runaway (due to mechanical intrusion, defects, or electrical abuse), it releases a superheated, highly pressurized gas plume containing vaporized electrolyte and carbon particles. This gas behaves as an electrically conductive fluid. In conventional battery packs, if this gas vents randomly into the pack cavity, the blasting hot airflow … Read more
Author: Dominic Pascal Förstermann, Akkuracy Battery chemistry choices affect everything from product safety certifications to insurance and procurement decisions — yet the common viewpoint remains “LFP is safe, NMC is dangerous.” But is that actually true? This article looks at the empirical data. In order to describe the safety aspects fully, it is split into … Read more
AION Engineering INC Safety is at the core of every lithium-ion cell design. To ensure reliable operation in demanding applications, the cell assembly and structure integrate multiple layers of protection. These features collectively reduce the risk of failure, overheating, or explosion. PTC (Positive Temperature Coefficient Device) The PTC acts as a resettable fuse: Applications: CID … Read more
Authors: Antonio Garcia Martinez, Carlos Micó, Imad Elkourchi, and Jaime Martín CALBET (CALorimetric Battery Energy Tool) is an in-house thermodynamic model developed at CMT – Clean Mobility & Thermofluids, Universitat Politècnica de València (UPV) to analyze the thermal runaway (TR) behavior of lithium-ion cells under accelerating rate calorimetry (ARC) conditions. The model has been designed to provide a fast, robust, and … Read more
The Current Interrupt Device (CID) in a cell is designed to electrically disconnect a cell if the internal pressure increases beyond a design point. If the gas pressure increases further the burst disc breaks and the gas is vented. However, is the CID operation safe under High Voltages (HV)? As the CID opens the circuit … Read more
Electrolyte detection is a possible way of seeing early cell failures where a soft vent results in electrolyte being vented and dispersed into the pack volume. This soft venting of electrolyte happens prior to a cell going into thermal runaway. Liu et at [1] look at the development of an electrolyte sensor that measures Ethyl … Read more