Multifunctional ceramic-reinforced nanocomposite hydrogel for thermal runaway propagation blocking and heat dissipation of lithium-ion battery modules

As the energy density and capacity of lithium-ion batteries (LIBs) continues to increase, safety issues caused by thermal runaway propagation (TRP) have become one of the most significant threats to electric vehicles (EVs) and energy storage systems (ESS). Reducing the risk of TRP is important for the widespread use of LIBs. In this study, a novel hydrogel and glass fiber (GF) composite thermal insulator was fabricated using a skeletal structure optimization technique to inhibit TRP in LIB modules. Mechanical and thermal insulation test results show that by optimizing the formulation and structural design, the maximum compressive strength of the composite hydrogel is increased from 10.32 MPa to 36.32 MPa, and the material has a low thermal conductivity (0.03145 W·m⁻¹·K⁻¹) after dehydration, which can provide continuous thermal protection for the battery. In thermal stability tests, the material demonstrated excellent flame retardancy with a peak HRR release rate of 45.68 KW/m², a reduction of 51.17 % compared to when no HAP was added. The material is also environmentally friendly, with total CO and CO₂ emissions of only 0.39 g, or 2.67 % of total emissions. A study of TRP suppression behavior was carried out on a fully charged 18650-NCM811 battery pack (3 × 3 arrangement). The results showed that filling 4 mm composite hydrogel was able to extend 1442 s, 1319 s and 1405 s, with a maximum temperature difference between batteries averaging 510.4 °C, and drastically reduce the size of the TRP compared to the blank control group when the heat source was at the corner, side and center, respectively. In addition, the material exhibits excellent thermal management performance, with the maximum temperature of the hydrogel-cooled battery module at 3C discharge multiplier being only 62 °C, a 19.7 % reduction on the air convection-cooled battery module (77.2 °C). This study provides a cost-effective and environmentally friendly solution for TRP suppression in LIB modules.