1. A vehicular transformer mounted on the roof of a vehicle, comprising:
a tank configured to house a transformer body and filled with refrigerant;
a plurality of cooling pipes arranged above the tank and configured to cool the refrigerant by heat exchange between the refrigerant and the outside air; and
a conservator arranged laterally to the tank in alignment with the tank along a travelling direction of the vehicle and configured to be in communication with the tank.
2. The vehicular transformer according to claim 1, further comprising an inclination portion which is configured to ascend obliquely toward the transformer body and extend toward the plurality of cooling pipes.
3. The vehicular transformer according to claim 1 or 2, wherein
the plurality of cooling pipes are arranged side by side in the height direction and arranged side by side in the horizontal direction at each height, and
the number of the cooling pipes arranged in the horizontal direction at each height is greater than the number of the cooling pipes arranged in the height direction.
4. The vehicular transformer according to any one of claims 1 to 3, wherein each of the plurality of cooling pipes is a flat pipe.
5. The vehicular transformer according to any one of claims 1 to 4, wherein the plurality of cooling pipes cover the tank when viewed from above the tank.
6. The vehicular transformer according to any one of claims 1 to 5, wherein each of the plurality of cooling pipes is configured to extend along the travelling direction of the vehicle.