With the rapid popularization of household energy storage systems, the number of retired household energy storage batteries is increasing year by year, making their recycling an urgent issue related to environmental protection, resource utilization, and the sustainable development of the energy storage industry. Household energy storage batteries, mainly lithium-ion batteries (such as LiFePO4 and ternary lithium batteries), have a service life of 10-15 years. When their capacity degrades to 70-80% of the original rated capacity, they can no longer meet the needs of household energy storage and enter the retirement stage. If these retired batteries are not properly recycled, they may leak toxic and harmful substances such as electrolytes and heavy metals, causing soil and water pollution, and posing a threat to ecological environment and human health. On the contrary, retired household energy storage batteries are “treasure troves” of resources, containing valuable metals such as lithium, cobalt, nickel, and iron. Recycling these metals can not only reduce the demand for raw material mining but also reduce the carbon footprint of battery production by up to 40%, achieving economic and environmental benefits.

The recycling process of household energy storage batteries is a complex and high-tech process, which mainly includes four key links: collection and sorting, discharge and dismantling, material recovery, and reuse. In the collection and sorting link, specialized facilities use AI-powered robots to sort batteries by chemistry, distinguishing between lithium-ion, lead-acid, and other types of batteries, to ensure that different types of batteries are recycled through appropriate processes. At present, the collection system of household energy storage batteries is still not perfect in many regions, with problems such as scattered collection points, low collection rate, and high collection costs. To solve these problems, many countries and regions are establishing a standardized collection system, including setting up special collection points in communities, shopping malls, and battery sales stores, and implementing a deposit system to encourage users to hand over retired batteries. For example, in some European countries, consumers can return retired household energy storage batteries to the place of purchase and receive a certain deposit refund, which effectively improves the collection rate.

In the discharge and dismantling link, retired batteries need to be discharged first to eliminate potential safety hazards such as short circuits and explosions. Specialized facilities use liquid nitrogen to neutralize the remaining charge of the batteries, ensuring the safety of the dismantling process. Then, workers wearing professional protective equipment disassemble the batteries, separating the battery modules, casings, and electronic components (such as battery management systems). This link requires strict operational standards to avoid damage to the battery cells and the leakage of toxic substances. In the material recovery link, enterprises use technologies such as hydrometallurgy and pyrometallurgy to extract valuable metals from battery cells. For example, Redwood Materials uses hydrometallurgy technology to recover more than 95% of critical minerals such as lithium, cobalt, and nickel from retired lithium-ion batteries. The recovered metals can be reused in the production of new batteries, forming a circular industrial chain.

Despite the significant progress in household energy storage battery recycling technology, the industry still faces many challenges. Globally, only 5% of lithium-ion batteries are recycled, mainly due to three major obstacles: the “sticky tape” dilemma, transportation difficulties, and lack of standardization. The adhesives binding battery cells require manual removal, which is time-consuming and labor-intensive; the cost of shipping spent batteries often exceeds their scrap value, making transportation uneconomical; with more than 100 types of batteries on the market, the lack of uniform recycling standards and technical specifications makes it difficult to achieve large-scale and efficient recycling. To address these challenges, governments, enterprises, and research institutions are working together to promote technological innovation and policy support. Sweden’s Northvolt now uses 30% recycled materials in new batteries, and the EU’s “battery passport” initiative tracks battery components like FedEx tracks packages, improving the traceability and standardization of battery recycling. With the continuous improvement of recycling technologies and the improvement of relevant policies, the recycling rate of household energy storage batteries is expected to increase significantly in the next 5-10 years, promoting the sustainable development of the household energy storage industry.