Résumé
The battery is an indispensable puzzle in the current roadmap towards a carbon-neutral world. With the soaring production, the battery itself is unexpectedly becoming a sustainability problem for society. Increasing attention is thus placed on the life cycle of batteries entailing the second life and recycling of batteries, relying on the monitoring of batteries' state and the classification of retired batteries by sensors. Battery sensors that decode the fundamental physical/chemical processes are thus poised to maximize the quality, reliability, lifetime, and safety of batteries and to minimize the environmental footprint. Fiber optic sensors stand out by virtue of their miniature size, insulating nature, electromagnetic immunity, and versatile sensitivities. In this Perspective, we discuss the promise and challenges of commercializing smart sensing for batteries and highlight how fiber optic sensors can synergize with paradigm shifts, including cell to pack and cell to chassis technologies.