Cooling system for electric vehicles

1. A cooling system for a vehicle, the cooling system comprising:

a first cooling circuit configured to cool a battery by coolant that circulates in accordance with operation of a first circulation pump and exchanges heat with a first heat exchange module;

a second cooling circuit configured to cool a power electronic (PE) module by coolant that circulates in accordance with operation of a second circulation pump and exchanges heat with a second heat exchange module, the second cooling circuit being configured so that the coolant in the first cooling circuit circulates through the second cooling circuit; and

a reservoir tank, which is continuously connected to the first and second cooling circuits to remove air in the coolant flowing through each of the first and second cooling circuits in the reservoir tank; and

a first parallel circulation passage connected between a rear end portion of the first heat exchange module and a front end portion of the first circulation pump;

a second parallel circulation passage connected between a rear end portion of the second heat exchange module and a front end portion of the second circulation pump; and

a series circulation passage connected between the first parallel circulation passage and the second parallel circulation passage,

wherein the reservoir tank is disposed on the series circulation passage.

2. The cooling system of claim 1 , wherein the reservoir tank is connected between the first cooling circuit and the second cooling circuit.

3. The cooling system of claim 1 ,

wherein the series circulation passage includes:

a first series circulation passage connected from a front end portion of the first parallel circulation passage to a rear end portion of the second parallel circulation passage; and

a second series circulation passage connected from a front end portion of the second parallel circulation passage to a rear end portion of the first parallel circulation passage, and

wherein the reservoir tank is disposed on the first series circulation passage.

4. The cooling system of claim 1 , further including:

a mode-switching valve provided at a point where the coolant in the second cooling circuit is branched into the second parallel circulation passage and the series circulation passage for switching a direction of flow of the coolant; and

a controller configured to implement an independent cooling mode in which the coolant circulates independently in each of the first and second cooling circuits and an integrated cooling mode in which the coolant circulates in the first and second cooling circuits by switching the mode-switching valve depending on an outside air temperature and a battery temperature.

5. The cooling system of claim 4 , wherein when the outside air temperature and the battery temperature are equal to or greater than a predetermined temperature, the controller is configured to control the mode-switching valve so that the mode-switching valve opens the second parallel circulation passage and closes the series circulation passage to implement the independent cooling mode.

6. The cooling system of claim 5 ,

wherein the second heat exchange module includes a heat pump and a radiator,

wherein the cooling system further includes a heat exchange module switching valve disposed at a point where the coolant is branched into the radiator and the heat pump at a rear end portion of the PE module, and

wherein the controller is configured to control the heat exchange module switching valve to open a first port thereof on the radiator and to close a second port thereof on the heat pump.

7. The cooling system of claim 4 , wherein when the outside air temperature is less than a predetermined temperature and the outside air temperature is less than the battery temperature, the controller is configured to control the mode-switching valve so that the mode-switching valve closes the second parallel circulation passage and opens the series circulation passage to implement the integrated cooling mode.

8. The cooling system of claim 7 , further including:

wherein the second heat exchange module includes a heat pump and a radiator,

wherein the cooling system further includes a heat exchange module switching valve disposed at a point where the coolant is branched into the radiator and the heat pump at a rear end portion of the PE module, and

wherein the controller is configured to control the heat exchange module switching valve to open a first port thereof on the radiator and to close a second port thereof on the heat pump.

9. The cooling system of claim 1 ,

wherein the second heat exchange module includes a heat pump and a radiator, and

wherein the cooling system further includes:

a heat exchange module switching valve disposed at a point where the coolant is branched into the radiator and the heat pump at a rear end portion of the PE module, wherein the heat exchange module switching valve is configured to enable the coolant that has passed through the PE module to flow to the radiator or to the heat pump; and

a controller configured to control a mode-switching valve to close the second parallel circulation passage and to open the series circulation passage when an outside air temperature is less than a predetermined temperature and the outside air temperature is less than a battery temperature.

10. The cooling system of claim 1 ,

wherein in the first cooling circuit, the first circulation pump, the battery, and

wherein the first heat exchange module is provided in plural, and the provided first heat exchange modules are mounted in series.

11. The cooling system of claim 1 ,

wherein in the second cooling circuit, the second circulation pump and the PE module are mounted in series, and

wherein the second heat exchange module is provided in plural, and the provided second heat exchange modules are arranged in parallel at a rear end portion of the PE module.