Lead-acid batteries are classic energy storage devices in the photovoltaic energy storage field. With excellent cost advantages, they have long been suitable for small and medium-sized photovoltaic energy storage scenarios. Compared with lithium batteries, they have lower initial purchase costs, mature technical systems, and complete production and operation supporting systems, which greatly reduce the implementation threshold of photovoltaic energy storage projects. In remote off-grid photovoltaic power stations, solar street lamps and small household photovoltaic systems, lead-acid batteries can stably store excess solar energy during the day to ensure continuous power supply at night and on cloudy days. Meanwhile, they have a sound recycling system to reduce subsequent replacement costs. Despite low energy density, they remain a cost-effective choice for photovoltaic projects with limited budgets and moderate power demand.