A battery module and methods for bonding cell terminals of battery cells together are provided. The battery module includes a first battery cell having a first cell terminal, and a second battery cell having a second cell terminal. The battery module further includes an exothermal reactive layer having first and second sides. The first and second sides are disposed adjacent to the first and second cell terminals, respectively. The exothermal reactive layer is configured to ignite to form a bonding joint between the first and second cell terminals in response to a laser beam contacting at least a portion of the exothermal reactive layer.