Failure propagation in multi-cell lithium ion batteries

Abstract

Traditionally, safety and impact of failure concerns of lithium ion batteries have dealt with the field failure of single cells. However, large and complex battery systems require the consideration of how a single cell failure will impact the system as a whole. Initial failure that leads to the thermal runaway of other cells within the system creates a much more serious condition than the failure of a single cell. This work examines the behavior of small modules of cylindrical and stacked pouch cells after thermal runaway is induced in a single cell. Cylindrical cells are observed to be less prone to propagate owing to the limited contact between neighboring cells. The electrical connectivity is found to be impactful as the 10S1P cylindrical cell module did not show failure propagation through the module, while the 1S10P module had an energetic thermal runaway consuming the module minutes after the initiation failure trigger. Modules built using pouch cells conversely showed the impact of strong heat transfer between cells. In this case, a large surface area of the cells was in direct contact with its neighbors, allowing failure to propagate through the entire battery within 60-80 seconds for all configurations (parallel or series) tested.

Li-Ion Battery Fire Hazards and Safety Strategies

“…In their work, the thermal runaway onset time is defined as the moment that the temperature increased at least 10 • C in a second, and it was found that the thermal runaway in the other cells started at a temperature only around 100 • C. Enlarging the space between cells in a battery pack can decrease the probability of thermal runaway propagation [23]. Lamb et al [24] found that the electrical connection on a battery pack can work as the thermal conducting pathway, and a battery pack with different electrical configurations presented different behaviors during the thermal runaway event. A battery pack in which six 18650 batteries were fully connected in series remained intact after the thermal runaway, but the other battery pack, which was fully connected in parallel, was destroyed.…”

Thermal runaway hazard characteristics and influencing factors of Li‐ion battery packs under high‐rate charge condition

“…8 Ohsaki found the rapid exothermic reaction of the delithiated cathode and electrolyte triggered the reaction between the overcharged anode (de-posited lithium) and the electrolyte, which led to thermal runaway. 10,11 In the charging of Li-ion battery pack study. In a battery pack, the burning behavior of the individual cells will affect adjacent cells, resulting in an overall failure of the battery pack.…”

Nominal energy optimisation method of constrained battery packs through the iteration of the series-parallel topology

“…On the other hand, Chiu et al analysed the thermal implications, such as capacity fade, contrasting between cells connected in parallel and in series. In addition, Lamb et al studied the thermal runaway propagation in different series‐parallel topologies.…”