Every pack designer faces an early fork: cool the cells with air or with liquid. The choice ripples through cost, weight, complexity and how hard the pack can be pushed. Two 2021 grants from the industry's heavyweights show the fork being taken in opposite directions.LG Chem's US11177517B2 claims an air-cooling battery pack with an improved assembling structure — air-cooling because it is cheap, light and mechanically simple: you move air past the cells and call it done. CATL's US11133543B2 claims a thermal-management device and battery pack oriented toward liquid-based cooling, the approach that dominates high-performance and fast-charge applications.The physics decides the trade. Air carries heat poorly; liquid carries it far better. For a low-power application — a modest pack that never fast-charges — air-cooling is adequate and you pocket the cost savings. For a performance EV or a pack that must accept a fast charge without overheating, liquid is close to mandatory, and you pay for the pumps, plumbing and sealing.Does it pencil? It depends entirely on the duty cycle. Air-cooling that saves a few hundred dollars per pack is a good deal if the pack never sees the loads that would cook it. The same air-cooling is a false economy if it shortens pack life under hard use — the warranty claims and capacity fade would erase the upfront savings.The strategic tell is that both LG and CATL filed in the same year on opposite approaches. That is not indecision; it is product segmentation. The big cell makers serve everything from cheap commuter cars to performance vehicles, and they need IP across the cooling spectrum to match each duty cycle profitably.For readers reconciling a pack's spec sheet to its real economics, cooling method is a fast diagnostic. An air-cooled pack marketed for fast charging deserves skepticism; a liquid-cooled pack in a low-power product may be over-engineered. The cooling choice should match the load, and when it does not, ask why.
“Disclosed is an air-cooling battery pack, which includes a cell assembly having a plurality of cells stacked therein; an air duct disposed to contact the cell assembly and having an air passage formed therein to allow a cooling air to move therethrough; a coupling groove formed at the air duct to el…”— U.S. Patent No. 11,177,517 source