A portable oxygen concentrator includes at least one separation mechanism and an oxygen storage tank, where the separation mechanism is connected to the oxygen storage tank and includes an air bag and a molecular sieve tank that is filled with a molecular sieve for adsorption. The air bag has an air inlet and an air outlet. The air bag is connected to the molecular sieve tank through a valve group, which includes a first single valve and a second single valve. The air bag is connected to the molecular sieve tank through the first single valve. Each of the two ends of the molecular sieve tank has at least one gas outlet. When an inner space of the air bag is compressed and expanded once, the molecular sieve in the molecular sieve tank adsorbs and desorbs once.

A portable oxygen concentrator includes at least one separation mechanism and an oxygen storage tank, where the separation mechanism is connected to the oxygen storage tank and includes an air bag and a molecular sieve tank that is filled with a molecular sieve for adsorption. The air bag has an air inlet and an air outlet. The air bag is connected to the molecular sieve tank through a valve group, which includes a first single valve and a second single valve. The air bag is connected to the molecular sieve tank through the first single valve. Each of the two ends of the molecular sieve tank has at least one gas outlet. When an inner space of the air bag is compressed and expanded once, the molecular sieve in the molecular sieve tank adsorbs and desorbs once.