Heat exchanger, heat exchange assembly, and heat management system

A heat exchanger, wherein the heat exchanger comprises a first heat exchange region and a second heat exchange region;

• the first heat exchange region comprises a first plate, and the second heat exchange region comprises a second plate;
• the heat exchanger further comprises a third plate and a fourth plate;
• a body portion of the third plate is located between the first plate and the fourth plate, and a body portion of the fourth plate is located between the third plate and the second plate;
• the second heat exchange region comprises two fluid flow channels, wherein heat is allowed to be exchanged between the two fluid flow channels;
• the first heat exchange region comprises a first hole passage and a second hole passage, the second heat exchange region comprises four passages, namely a first hole passage, a second hole passage, a third hole passage and a fourth hole passage, two holes for communication, namely a first hole and a second hole, are provided at a side, closest to the first heat exchange region, of the second heat exchange region, and the first hole and the second hole are provided in the second plate;
• the third plate comprises at least two matching portions, each of the at least two matching portions of the third plate is provided with a matching hole, and the at least two matching holes of the third plate comprises a first matching hole and a second matching hole;
• the fourth plate comprises at least two matching portions, each of the at least two matching portions of the fourth plate is provided with a matching hole, and the at least two matching holes of the fourth plate comprises a third matching hole and a fourth matching hole;
• one of the at least two matching portions of the third plate where the second matching hole is located to face and secured by welding to one of the at least two matching portions of the fourth plate where the fourth matching hole is located, and the second matching hole of the third plate faces and is in communication with the fourth matching hole of the fourth plate;
• the second plate comprises at least one matching portion, one of the first hole and the second hole is provided in one of the at least one matching portion of the second plate, another one of the at least two matching portions of the fourth plate where the third matching hole is located to face and secured by welding to the one of the at least one matching portion of the second plate, and the third matching hole of the fourth plate is in communication with the one of the first hole and the second hole provided in the one of the at least one matching portion of the second plate;
• and
• the second hole passage of the first heat exchange region is in communication with one of the hole passages of the second heat exchange region through the third plate and the fourth plate;
• the third plate comprises a first main plate face and a second main plate face opposite to each other, and the fourth plate also comprises a first main plate face and a second main plate face opposite to each other;
• the one of the at least two matching portions of the third plate where the second matching hole is located protrudes towards the fourth plate with respect to the first main plate face of the third plate, and the first matching hole of the third plate is in communication with a space between the third plate and the fourth plate;
• one of the at least two matching portions of the fourth plate where the fourth matching hole is located protrudes towards the third plate with respect to the second main plate face of the fourth plate, and another one of the at least two matching portions of the fourth plate where the third matching hole is located protrudes towards the second plate with respect to the first main plate face of the fourth plate;
• and
• the fourth matching hole of the fourth plate is in communication with a space between the fourth plate and the second plate, and the third matching hole of the fourth plate is in communication with a space between the third plate and the fourth plate.