Why temperature decides battery life
Lithium cells are sensitive to temperature on three fronts: usable capacity, cycle life and safety margin. Operating above 30℃ for long periods accelerates calendar aging, while low-temperature fast charging raises the risk of lithium plating. The job of cabinet thermal management is to keep most cells inside the recommended window and minimize the spread between the hottest and coldest cell.
Heat sources inside a storage cabinet
Three sources dominate: cell reaction heat during charge and discharge, resistive heat from busbars and cable joints, and switching losses in the PCS and distribution components. For a 100kWh-class outdoor cabinet, continuous heat release at full power typically runs from several hundred watts to over one kilowatt, and summer ambient plus solar gain must be added on top.
Sizing the cooling capacity
A practical rule is continuous heat load times a 1.2 safety factor, plus an ambient adder, then verified against cabinet leakage and the target setpoint. Every 1℃ of extra setpoint tolerance cuts required capacity by roughly 3–5%, but also eats into battery life margin. Where day-night peaks differ strongly, inverter-driven units save energy and reduce start-stop shock compared with fixed-speed models.
Air cooling vs liquid cooling
Air-cooled designs are simple, easy to service and cheap to retrofit, which suits distributed cabinets under 100kWh. Liquid cooling delivers higher heat flux capability, better uniformity and lower noise, fitting container-scale or high-rate storage. The two are not exclusive: hybrid architectures with cold plates plus air assist are common.
Uniformity requirements
Cell-to-cell temperature spread should generally stay within 5℃. Uniformity comes from airflow design, not raw capacity: supply and return paths must sweep every battery rack without dead zones. Air ducts, staggered shelf layouts and zoned circulation are the usual remedies.