Data and videos for the comparison of thermal propagation and cycle performance of multiple lithium-ion batteries in air and insulating oil

The propagation test of lithium-ion battery pack was conducted in an environment of air and insulating oil. The test results showed the difference in the phenomenon in which fire propagation to surrounding cells, when a cell composing a battery pack is thermal runaway in two environments. The temperature of the cells in the battery pack was measured during propagation test. A cycle test was also conducted to check whether there was an abnormality in cell performance immersed in insulating oil. The residual capacity and internal resistance, insulation resistance data of the cell are presented in the two environments.


a b s t r a c t
The propagation test of lithium-ion battery pack was conducted in an environment of air and insulating oil.The test results showed the difference in the phenomenon in which fire propagation to surrounding cells, when a cell composing a battery pack is thermal runaway in two environments.The temperature of the cells in the battery pack was measured during propagation test.A cycle test was also conducted to check whether there was an abnormality in cell performance immersed in insulating oil.The residual capacity and internal resistance, insulation resistance data of the cell are presented in the two environments.

Value of the Data
• Experimental results can be a reference for the safety analysis of thermal propagation of lithium-ion batteries.• Videos and pictures clearly presented the experiment conditions which can be an important design consideration of battery systems • The new concept of cooling method for Lithium-ion battery system is proposed by experimental results

Data Description
The dataset in this article describes the comparison data of thermal propagation and cycle performance of multiple lithium-ion batteries in air and insulating oil.Thermal propagation test video in air and insulating oil including thermal imaging video can be found at https://data.mendeley.com/datasets/z95cb7f9mr/2 .Also, the temperature data of thermal propagation test in air and insulating oil are included.The Video 1 shows the front side of the test object while thermal propagation test in air.The Video 2 shows the thermal imaging video of the test object while thermal propagation test in air.The Video 3 presents the front side of the test object while thermal propagation test in insulating oil.The Video 4 presents the thermal imaging video of the test object while thermal propagation test in insulating oil.The data "Temperature data for thermal propagation test 1" show the temperature data of overcharged batteries, adjacent batteries, and positions of external enclosure as shown in Fig. 2 while thermal propagation test in air.Also, the data "Temperature data for thermal propagation test 2 show the same part and positions as shown in Fig. 2 while testing in insulating oil.

Experimental Design, Materials and Methods
Experiments were implemented to study the thermal propagation prevention performance and cycle characteristic in air and insulating oil.The dataset of this article provides better understanding of the thermal propagation aspects and cycle performance in air and insulating oil.Experiments in this article were implemented at Korea Electrotechnology Research Institute (KERI).The paraffin series insulating oil is used for these tests.The electrical resistance of insulating oil is 56.2 × 10 3 G m at 20 °C and the electrical conductivity is 0.1300 W/mK at 20 °C, the density is 808.9 kg/m 3 at 20 °C.

Thermal propagation test
The experiment data were measured by using K-type thermocouple, data logging equipment, camera and thermal imaging camera.The thermocouples are set as shown in Fig. 11   Battery cells are developed by the overcharge to force into thermal runaway.The overcharge current of this cell is 86.4A which can be the optimized condition to make a thermal runaway without operating current interrupt device(CID).Assumed thermal propagation condition is that 3 of overcharge cells should be in case of thermal runaway out of 4 of overcharge cells as shown in Fig. 2 (a).

Cycle performance test
The experiment data were measured by using K-type thermocouple, data logging equipment, battery tester, battery impedance meter.Fig. 12 shows the experimental setup for the cycle performance test.The thermocouples are K-type with 0.254 mm diameter, 1300 K measurement range and ± 0.4% precision.The transmitted temperature data by thermocouples are recorded by Hioki data logging equipment.
Maccor battery tester is used to charge and discharge battery cells and measure the DC internal resistance of each battery cell.Hioki battery impedance meter is used to measure the AC internal resistance of each battery cell.JEIO Tech and Daewon Science temperature chamber is used to maintain temperature condition.
The equipment list for cycle performance test is shown in Fig. 13 .The conditions such as parameters for the test are shown in Fig. 14 .Also, the procedure of cycle performance test is described in Fig. 14 .

Limitations
Not applicable.

Fig. 1
Fig. 1 (a) shows the single cell and the configuration of the battery module for 8 × 6 for thermal propagation test in air and insulating oil and Fig. 1 (b) presents the configuration that thermocouples and charging wires to make cells thermal runaway are connected.Fig. 2 (a) and (b) displays the thermal runaway cells positions and temperature measuring position by thermocouples.Fig. 3 (a) shows the installed battery modules in the test room and Fig. 3 (b) presents the battery modules after the thermal propagation test.Fig. 4 (a) and (b) shows the temperature of battery cells, module and ambient temperature in air and insulating oil.Thermal propagation test video in air and insulating oil including thermal imaging video can be found at https://data.mendeley.com/datasets/z95cb7f9mr/2 .Also, the temperature data of thermal propagation test in air and insulating oil are included.The Video 1 shows the front side of the test object while thermal propagation test in air.The Video 2 shows the thermal imaging video of the test object while thermal propagation test in air.The Video 3 presents the front side of the test object while thermal propagation test in insulating oil.The Video 4 presents the thermal imaging video of the test object while thermal propagation test in insulating oil.The data "Temperature data for thermal propagation test 1" show the temperature data of overcharged batteries, adjacent batteries, and positions of external enclosure as shown in Fig.2while thermal propagation test in air.Also, the data "Temperature data for thermal propagation test 2 show the same part and positions as shown in Fig.2while testing in insulating oil.

Fig. 5
Fig. 5 shows battery cells tested in air and insulating oil.Fig. 6 (a) presents the experimental setup for measuring the insulation resistance in air and insulating oil.The results of insulation

Fig. 1 .
Fig. 1.The configuration of test module.The battery cells are LG Energy Solution 21,700 type Lithium-ion batteries which are charged to 100% SOC (4.8 Ah rated capacity) as shown in (a).The air and insulating oil configurations are identical to each other.The polycarbonate is used for the module housing material.The shortest distance between cells is 2.3 mm as shown in (a).

Fig. 2 .
Fig. 2. Position of thermal runaway cells positions and temperature measuring point.The overcharge cells (No. 1 ∼ No. 4) of (a) are used to make thermal propagation of each module.The temperature of adjacent cells (No. 5 ∼ No. 11) of (a) and front, back, left, right and top side of each module of (b) are measured.

Fig. 3 .
Fig. 3. Experimental setup before and after the thermal propagation test .The battery modules are installed in air and insulating oil as shown in (a).The volume of enclosure is 25.0 L and 15.0 L of insulating oil is added to the enclosure.The (b) presents the battery module after the thermal propagation test.There is no disturbance while the test started to ended and each module observed 24 h after thermal runaway of overcharge cells.
Fig. 4. Temperature of battery cells, each module and enclosure during thermal propagation test.The measured temperature tested in air is shown in (a), tested in insulating oil is presented in (b) and the measurement position is a center of the cell's body.The front of enclosure temperature is only presented as shown in (a, b) among other temperature of enclosure because of simple observation through waveforms.Other temperature of enclosure can be found in https://data.mendeley.com/datasets/z95cb7f9mr/2 .

Fig. 6 .
Fig. 6.Insulation resistance results in air and insulation oil.The case used for measuring insulation resistance is made of polypropylene material in (a).The results of insulation resistance are over the 150 G which are over the measuring range in (b).

Fig. 7 .
Fig. 7. Cycle performance test setup.The cycle performance test setup is shown as (a).The (b) displays the position of thermocouples to measure the temperature of cells.Thermocouples are attached on the body of each cell.The volume of enclosure is 19.4 L and 11.2 L of insulating oil is added to the enclosure.The jig for fixing the cell is made of Polyoxybenzylmethyleneglycolanhydride material as known as bakelite.

Fig. 8 .
Fig. 8.The capacity retention of battery cells.The capacity retention of each battery cell in air and insulating oil is presented as shown in (a) and (b).

Fig. 9 .
Fig. 9.The DC-IR and AC-IR of battery cells.The AC-IR and DC-IR results of cells in (a) and (b) are measured after every 50 cycles.

Fig. 10 .
Fig. 10.The temperature of battery cells.The temperature results in air and insulating oil are displayed.The temperature waveforms of cells are displayed for 200th cycle.

Fig. 11 .
Fig. 11.The experimental setup for thermal propagation test.Thermocouples are connected and set as shown in (a).Thermal imaging camera, video camera, power supply for overcharging cells and data logging equipment is set as shown in (b).

Fig. 12 .
Fig. 12.The experimental setup for cycle performance test.The battery cells are connected with battery tester in each temperature chamber.Ambient temperature is maintained at 25 °C of each battery cell by temperature chamber.

Fig. 13 .
Fig. 13.The summary of experimental setup for tests.The equipment list for thermal propagation test and Cycle performance test.The maker, purpose and specification of equipment are clearly summarized for each test.

Fig. 14 .
Fig. 14.Conditions for cycle performance test.Parameters for cycle performance test are displayed.All conditions are applied equally for each cycle.D.C. and A.C resistance measured at the end of every 50 cycles.