# A Simplified Analysis to Predict the Fire Hazard of Primary Lithium Battery
## 2 Experimental Description  
The batteries used in this research are Panasonic (Osaka Prefecture, Japan) CR123A type lithium cells and Figure 1 shows the appearance and physical size parameters of the batteries (diameter 17 mm, height 34.2 mm). The specifications of the battery obtained from the product brochure were: nominal voltage 3 V, nominal capacity 1550 mAh, and these batteries can be used from \(-40\)\({}^{\circ}\)C to 85 \({}^{\circ}\)C. Panasonic CR123A is one of the most common lithium primary batteries using lithium as the anode and manganese dioxide (MnO\({}_{2}\)) as the cathode. This battery is popular in cameras, game counters, photo equipment, medical equipment, tactical flashlights, and home security systems. This kind of battery has a wide operating temperature range, long shelf life, and is low cost. They are not normally used in large quantities together, but are often packaged together for transportation and storage. There is a large fire risk during these processes, especially during air transport.  
The most important parameter for defining fire hazard in this research is heat release rate (HRR). To cater to the current need, an in-situ calorimeter was constructed, which consisted of a burning chamber, an exhaust system, and a katharometer system. A detailed diagram of the in-situ calorimeter and experimental setup is shown in Figure 2. The dimensions of the burning chamber were 1.2 \(\times\) 1.2 \(\times\) 1.2 m. The chamber had a 0.15 m gap at the bottom to allow the intake of fresh air. The gases were collected and removed by an exhaust pump with a volumetric flow rate of 0.18 m\({}^{3}\) s\({}^{-1}\). In general, heater choices for test apparatuses have included gas-fired panels, electric resistance heaters, and flames. Gas-fired panels or flames affect the measurement of HRR. In this study, a 2 kW electric radiation heater coil twined by the electric resistance was used and placed under the batteries at a vertical distance of 10 mm. The batteries were placed on top of the wire net. The heat flux at the bottom of the battery specimen above the center of the heater was measured as 20 \(\pm\) 0.3 kW m\({}^{-2}\). Under this thermal radiation, lithium batteries can be easily ignited. When the battery caught fire and released gases, the combustion gas escaped from the combustion chamber via the pipe and then was ejected outside by the exhaust pump. Part of the combustion gas was collected, sampled, filtered, and dried at the back of the exhaust pipe, and analyzed in a Servomex 4100 gas analyzer (Servomex, Egham, UK), which was designed to provide 3 simultaneous gas stream measurements of oxygen, carbon dioxide, and carbon monoxide. The HRR measurement by the in situ calorimeter is based on the oxygen consumption principle [34; 35].  
Six groups of experiments were designed to study fire scenarios and examine the effects of different numbers of batteries (1, 2, 4, 9, 36, and 100 batteries) on the primary lithium battery fire behavior. In this study, the samples were heated with a constant power using a heater. Therefore, the heating rate for every experimental configuration was the same. The simulation enabled the creation of a heat release rate curve for primary lithium batteries based on t\({}^{2}\) fire model and MATLAB software (version 2014,  
Figure 1: Panasonic CR123A primary lithium battery.  
MathWorks, Natick, MA, USA) mathematical curve construction. The simulation results were also compared with the experimental results to verify the rationality and accuracy of the simulation results.