The HIDDEN project is developing self-healing processes to enhance the lifetime and to increase the energy density of Li-metal batteries by 50 % above the level achievable with current Li-ion batteries. The HIDDEN consortium is developing materials and associated processes for functional battery layers as scalable, industry- compatible manufacturing technologies enabling sustainable energy storage technology with longer battery lifetime and higher energy storage capacity for more efficient utilisation of sustainable, carbon- free energy production technologies. HIDDEN will develop novel self-healing thermotropic liquid crystalline electrolytes and piezoelectric separator technologies, investigate the use of protective additives with both these technologies, apply multi- scale modelling in electrolyte design, and use analysis algorithms to monitor dendrite growth. Technologies will be up- scaled from laboratory to industrial manufacturing processes, tested, and finally demonstrated by assembling battery cells with battery layers and the temperature control system. The project brings together a strong interdisciplinary consortium of seven partners, balanced between industry and research, with state-of-the-art backgrounds in battery chemistry and physics, materials modelling and analysis, up-scaling novel technologies by printing and coating, and the industrial assemby of battery cells. This is complemented by an external advisory board representing key industry end-users.