DE4333613C2 - Cooling system of an electric motor vehicle and an electric motor used therefor - Google Patents

Description

This invention relates to an electric vehicle cooling system and particularly to a cooling system for an electric vehicle that is suitable is, heat generating sections by recirculating a liquid coolant to cool.

In general, many are cooling and heating devices of electric vehicles of the air cooling type as disclosed in JP A 47-31317 (1972). Until now we have to cool len of sections of an electric motor a variety of methods known from one of which, as disclosed in JP A 48-60207 (1973), has a conduit for the coolant Telfluß applied, which is provided on an outer periphery of the stator another method, such as in JP A 1-131256 (1989), uses a spiral one Flow passage in a frame on the outer circumference of the stator is provided.

DE 92 02 466 U1 teaches a device for cooling drive compos nents and for heating a passenger compartment of a motor vehicle, in particular re of an electric vehicle, with a cooling circuit in which a heat exchanger is arranged, and one from an outflow opening of a passenger compartment to one Air duct extending to the supply air opening, from which part of the air flow is removed branched and / or fresh air can be supplied.

DE 37 38 412 A1 discloses a device for engine cooling with a Coolant circuit, which is a heat rope operable in a first coolant shear and preferably contains a bypass bypassing the cooler, wherein  the distribution of the coolant flow to the radiator and the bypass little least depending on the coolant temperature.

A liquid-cooled electric machine is described in DE 36 01 089 A1 ben, which is designed as an electric motor and as an alternative drive - in addition to an internal combustion engine - an omnibus. With an advantageous execution For example, the electrical machine consists of two cooling circuits, the first for the electric motor and the second for the internal combustion engine who applied the.

EP 0 484 548 A1 describes an electric automobile which is equipped with motors for Drive of wheels and with a cooling circuit for air conditioning in the Is provided inside the vehicle. This will cool the drive motor is sufficient that the coolant directly into the appropriate chambers inside the Mo tors is directed. The cooling system can be equipped with a heat pump for both Cooling mode as well as for heating mode can be used.

DE 24 51 221 A1 also discloses air heating for the interior of a by means of accumulators, control device and electric motor driven elec rocraft vehicle, with a supply air duct opening into the interior, one arranged in the supply air duct heat source, an exhaust duct, the battery mulators with their immediate heat content are used as heat sources are.

DE 41 08 074 C2 teaches an electronically controlled electric motor with a arranged on the engine control device, a processor stage and a Cooling fan comprises, wherein the housing of the control device of the housing of the motor is thermally and mechanically decoupled in that between the housing of the control device and the housing of the motor an air gap is arranged, which is bridged by narrow webs.  

Finally, DE 38 10 174 A1 describes a device for regulating the Coolant temperature of an internal combustion engine, especially in motor vehicles taught with at least one coolant temperature sensor, at least one another sensor for measuring an operating variable of the internal combustion engine, with a control device which receives the sensor output signals and which are dependent one of the sensor output signals and a set temperature of the coolant Control device for influencing the coolant temperature controls.

Electric motors tend to be large in size and scale because of the demands knowledge of increasing the running efficiency of motor vehicles and an amount of heat, that is generated in the electric motors and control devices increases noticeably according to the extent of their usage environment.

The power source of an electric motor vehicle is mainly a battery rie and the development of the battery has recently become more active. In particular it will necessary to retain the heat of the battery because of the battery characteristics fall off quickly at low temperature.

Furthermore, it is known the power of the battery to heat a resistor to use stationary wire heater for indoor heating in winter, since the e electric motor vehicle has a lower heating capacity than a motor vehicle Has internal combustion engine.

With the above conventional techniques one cannot be expected to maintain stable cooling and heating, since the electric motors and the control Air cooling type devices are lightweight due to the outside air temperature to be influenced.

It is the object of the invention to be a cooling system for an electric vehicle which is effective regardless of external temperature fluctuations  Air conditioning of the drive system of the vehicle ensured and in particular effective cooling or heating of the battery.

This object is achieved by a cooling system with the features according to claim 1 solved. Advantageous embodiments of the invention are described in the sub features specified claims.

According to the invention, a cooling system of an electric motor vehicle is provided that is able to cool and cool regardless of the seasons that is able to heat the vehicle interior by effective Ver application of the heat generated in an electric motor and a control device support, and a decrease in battery characteristics by restraint suppress the heat of the battery.

Furthermore, a structure is provided which is capable of effectively elect to cool romotor or a control device.

In one aspect, a non-freezing solution is used as a coolant turns and a forced recirculation of the non-freezing solution by one Heat source applied through a pipe.

In another aspect, the heat recirculates in an electric motor and a control device is generated by a battery and it becomes the one Heater heating passage provided with a cooling passage gear for the electric motor and the control device through a valve device is switchable.

In addition, a cooling line is adjacent to a heat generator Section of an electric motor or a control device provided.  

Non-freezing solution as a coolant flowing in a cooling pipe flows on the scope of a control device and an electric motor and exchanges the Heat with the heat from the control device and the electric motor is created to cool them. The heated, non-freezing solution is through a cooler and recirculated by a pump to return to the Cool to be fed.

A blower motor works to cool the radiator and it works with an electric pump to effectively cool when the outside air temperature is high.

Further advantages, features and possible uses of the present invention tion result from the following description of exemplary embodiments in connection with the drawing. The drawing shows:

Fig. 1 is a schematic diagram showing the approximate shape, a cooling system of an exporting shows the invention;

Fig. 2 is a schematic diagram showing a cooling system of another embodiment of the invention;

Fig. 3 is a flowchart showing the cooling flow passage of the embodiment shown in Fig. 2;

Fig. 4 is a graph showing the temperature condition of a sensor T1 in egg nem inlet of a control device wherein the sensor is used in the present invention;

Fig. 5 is a flowchart of control in the embodiment shown in Fig. 2;

Fig. 6 is a plan view of the control device;

Fig. 7 is a side view of the control device in Fig. 6;

Fig. 8 is a bottom view of the control device in Fig. 6;

Fig. 9 is a sectional view showing an arrangement of the cooling plate in the imple mentation form of the invention;

10a is a plan view of a control device, showing an arrangement of a cooling pipe of the embodiment of the invention.

Fig. 10b is a sectional view of the cooling pipe taken along line 10b-10b of Figure 10a.

FIG. 11a is a plan view of a control device, showing an arrangement of a cooling line to another embodiment of the invention;

Fig. 11b is a sectional view of the cooling pipe taken along line 11b-11b in Fig. 11a;

Fig. 11c is a sectional view of the cooling pipe taken along line 11c-11c in Fig. 11a;

Fig. 11d is a bottom view of the control device in Fig. 11a;

Fig. 12 is a view showing an arrangement of a cooling pipe of another embodiment of the invention;

Fig. 13 is a right side view of Fig. 12;

Fig. 14 is a sectional view taken along a line 14-14 of Fig. 12;

Fig. 15 is an enlarged sectional view of a part of Fig. 12;

Fig. 16 is an enlarged sectional view of a part of Fig. 12, showing another embodiment of the invention;

Fig. 17 is a side view of an electric motor used in the present invention;

Fig. 18 is a sectional view of the electric motor in Fig. 17;

FIG. 19a is a side view of a stator section of the electric motor in FIG. 17;

Fig. 19b is an enlarged view of a part of the stator section in Fig. 19a, indicated by P;

Fig. 20 is a side view of a component of the stator in Fig. 17;

Fig. 21a is a front view of a component of a stator as shown in Fig. 17, which is another embodiment of the invention; and

Fig. 21b is a side view of Fig. 21a.

An embodiment will be described hereinafter with reference to the drawings become.

Fig. 1 shows a cooling system of a control device and an electric motor for electric motor vehicles. The cooling system has a cooling line 5 , which is used for cooling a control device 1 , which controls the output of an electric motor, and the electric motor 2 , which drives the wheels, a cooler 3 for cooling a coolant and an electric pump 4 .

In the cooling line 5 , a coolant from a non-freezing solution is included. On the side of the radiator 3 , a radiator fan motor 6 is provided to forcibly cool the coolant.

In the above construction, an amount of heat generated in the control device 1 is almost equal to an amount of heat generated in the electric motor 2 , but a temperature of the amount of heat generated in the electronic parts constituting the control device 1 , such as. B. transistors, capacitors, etc., is 150 ° C or higher, which is very high and the thermal condition is very difficult for electronic parts that are low in thermal resistance. Therefore, in order to cool the system, the control device 1 and the electric motor 2 are arranged so that the control device 1 is cooled first and then the electric motor 2 , which is larger in thermal resistance, is cooled, thereby effective cooling under good to provide heat-balanced conditions.

Maximum cooling is required in the summer and at a time when the outside air temperature is high, usually at a time when the outside air temperature is 40 ° C or higher according to an automotive manufacturer's environmental test specification. At such a time, it is necessary to set the capacity of the radiator 3 , a flow rate of the radiator fan motor 6 and a circulation flow rate of the electric pump 4 so that the cooling is sufficient when the electric motor 2 is at full power. However, there are cases where the outside air temperature drops to about room temperature, and where the control device 1 and the electric motor 2 are cooled unnecessarily so much. A suitable embodiment for such cases is explained with reference to FIG. 2.

In Fig. 2, although a basic cooling circuit is the same as in Fig. 1, a case 7 of a battery is connected in parallel with intermediate connecting portions a and b of the cooling pipe 5 between the electric motor 2 and the radiator 3 , and a heater 8 and one Valve V3 are provided between the intermediate connecting portion b and the pump 4 so that the coolant can flow through through the valve V3. A line 5 a with a valve V1 is between the intermediate connecting portion a and the pump 4 a related party. A valve V2 is provided between the connecting sections A and B therebetween.

Functions of the cooling system in Figure 2 will be explained with reference to the following table:

Table 1

Contact resistance B << V2

In the above Table 1, the symbols C, Mo, B, P and R represent the Steuerervor device 1 , the electric motor 2 , the battery case 7 , the pump 4 and the cooler 3 , respectively.

As for the coolant path or the water path taken according to a change in the outside air temperature, a coolant path C-Mo-RP is taken in case ( 1 ) when the outside air temperature is high in summer, that is, 40 ° C or higher in which it is unnecessary to retain the heat of the battery and the valve V2 is opened so that the control device 1 and the electric motor 2 are cooled by the coolant which has been completely cooled by the radiator 3 . In this case, the cooling line 5 is connected to a cooling path 71 of the battery housing 7 to form a recirculation path, however, since the cooling path 71 has a high volume resistance, the coolant flows in a short circuit through the valve 2 and the valves V1 and V3 are closed. In case ( 2 ), forced cooling is performed according to the environmental conditions even if the outside air temperature is relatively cool, that is, lower than the usual temperature, and the valve opening and closing conditions are the same as in case ( 1 ). A value of a water temperature sensor T1, which is arranged at an inlet of the control device 1 , is detected and the valve V2 is closed and the radiator fan motor 6 is switched off at the value of approximately 45 ° C., ie in a temperature range in which the thermal resistance of the electronics rule Parts can be secured because forced cooling is unnecessary in such a temperature range.

In case ( 3 ), the outside air temperature drops further to approximately 5 ° C. in winter, the valve V1 is open and the coolant briefly closes the cooler 3 and is returned to the pump 4 . At this time, the blower motor 6 is basically switched off. However, when the inlet water temperature sensor value T1 reaches 65 ° C or higher, the valve V1 is closed and the coolant is recirculated through the radiator 3 . At this time, the blower motor 6 is turned on. In case ( 4 ), the outside air temperature further lowers, valve V2 is closed and valve V3 is open, the hot coolant flowing into heater 8 (H) and being recirculated to pump 4 . In this case, even if the inlet water temperature sensor T1 reaches 65 ° C or higher, the valve V2 is opened and part of the coolant is recirculated through the radiator 3 , whereby the temperature of the coolant is lowered and the cooled coolant is recirculated to the pump 4 . At this time, even if T1 <65 ° C, the Kühlerge blower motor 6 is turned on, as shown in Fig. 5.

In the case ( 5 ), the outside air temperature further lowers, the valve V1 is opened, the valve V2 is closed and the valve V3 is closed, the hot coolant being recirculated from the engine 2 through the cooling path 71 of the battery case 7 , and when the coolant temperature rises to a predetermined temperature, the valve V1 is closed to thereby recirculate the coolant through the radiator 3 . By repeating this operation, cooling and heating can be performed effectively under an energy saving condition. The order of the above patterns ( 3 ), ( 4 ), ( 5 ) in relation to the outside air temperature changes according to the capacity of the battery and the heater.

Fig. 3 shows a diagrammatic illustration of the above table, in the (1) to (5), the coolant paths or Kühlmittelflußmuster above represent the same as the outside air temperature conditions.

Fig. 4 shows conditions of an on-off control of the radiator fan motor 6 , the flow control of the pump 4 and the water temperature sensor value T1 of the control device inlet with respect to a change in the outside air temperature (Ta) at which the recirculation flow rate Gm maxi times 30 l / min is, e.g. B., and the flow rate is reduced to 5 l / min or so when the outside air temperature is lower. Fig. 5 shows a control flow of the cooling system, in which various values are shown as an example and the values change a little according to the size of the cooling system. In Fig. 5, M represents the cooler blower motor 6 , switch a start switch, P the electric pump 4 and Gw a flow rate of the coolant flowing through the pump 4 .

In step 501 , it is checked whether a start switch is on or not. If the start switch is off, a timer is deleted in step 506 and the radiator fan motor 6 and the pump 5 are switched off in step 507 , so that the coolant flow rate Gw is 0 l / min. In step 501 , if the start switch is on, the timer counts up in step 502 . In step 503 , if a value Ta of the outside air temperature sensor (Ta) is equal to or higher than a predetermined water temperature, e.g. B. 20 ° C or so, the pump 4 is turned on to recirculate the coolant to a predetermined maximum flow rate Gm, 30 l / min in step 504 . At the same time, the radiator fan motor 6 is turned on to lower the value (T1) of the water temperature sensor in step 505 . (The flow pattern ( 1 ) in the table.)

If an outside air temperature sensor value Ta is lower than the predetermined value 20 ° C (step 503 ) and equal to or higher than a predetermined value, e.g. B. 5 ° C in step 508 , the pump 5 is turned on to recirculate the coolant at the maximum flow rate of 30 l / min (step 509 ); when the water temperature sensor value (T1) is equal to or higher than a predetermined temperature, e.g. B. 45 ° C, the radiator fan motor 6 is switched on to lower the water temperature sensor value (T1) in steps 510 , 511 . Thereafter, when the water temperature sensor value (T1) becomes lower than the predetermined value of 45 ° C, the radiator fan motor 6 is turned off to reduce the power consumption in steps 510 , 512 . (The flow pattern ( 2 )).

Further, if the outside air temperature sensor value Ta is lower than a predetermined outside air temperature of 5 ° C in step 508 , the pump 4 is turned on to recirculate the coolant at a predetermined minimum flow rate of 5 l / min in step 513 and in step 514 , when the water temperature sensor is equal to or higher than a predetermined value of 65 ° C value (T1), the radiator fan motor 6 is turned on, the water temperature in step 515. ERS lower. Thereafter, when the water temperature sensor value T1 becomes lower than the predetermined value of 65 ° C in step 514 , the radiator fan motor 6 is turned off to raise the water temperature sensor value using the coolant with the higher temperature for the other cycle, thereby utilizing heat to effect (patterns (3), (4), (5)).

In the cases of any flow pattern above, the predetermined values have some difference to reduce lag in on / off switching operations. For example, the difference is such that if it is desired that the cooling fan motor 6 be turned on / off Performs off operation when the water temperature becomes 45 ° C, the blower motor 6 is turned on when the water temperature rises and reaches the temperature of 45 ° C, and the blower motor 6 is turned off when the water temperature reaches the water temperature of 43 ° C is lowered, e.g. B., and in this case the temperature difference of 45 ° C - 43 ° C = 2 ° C. This is the same as in the case of coolant recirculation. As in the embodiment of the present invention, the liquid or water cooling type cooling system as a whole is excellent compared to an air cooling type cooling system in that an installation space is small (by 5%), the weight is reduced (by 10% ), its maintenance is better (there is no clogging of the filter as with the air cooling type), the waste heat utilization is greater, the design is better, etc.

In addition, there is a great effect of exhaust gas utilization to save energy of the cooling fan motor 6 and the electric motor 2 , to support the heating of the heater 8 and to improve the battery performance.

Fig. 6, 7 and 8 show a condition that a plurality of IGBT 10 (insulating layer bipolar transistor), which are a main component of the control device 1, on each of an IGBT mounting plate 11 (U-phase), an IGBT Mounting plate 12 (V phase), and an IGBT mounting plate 13 (W phase) are mounted by fastening screws 14 . A cooling plate 15 is mounted by connecting screws 16 on the IGBT mounting plates 11 , 12 , 13 on which the IGBT 10 are mounted in a manner that the IGBT mounting plates 11 , 12 and 13 are each in close contact with the cooling plate 15 . The cooling plate 15 has a cooling line 17 with the verbun for cooling the cooling plate 15th The cooled cooling plate 15 cools the IGBT 10 .

Fig. 9 shows the condition when the IGBT mounting plate 11 , 12 , 13 is mounted on the cooling plate 15 , in which the IGBT mounting plate 11 , 12 , 13 is fixed to the cooling plate 15 by connecting screws 16 and the IGBT 10 mounted on the IGBT mounting plate 11 , 12 , 13 by the fastening screws 14 . The cooling plate 15 has holes at portions corresponding to the fastening bolts 14 to a survive the mounting screws to allow the cooling plate 15 fourteenth Furthermore, a cooling effect is further improved by directly fastening the IGBT 10 to the cooling plate 15 using the fastening screws. The cooling line 17 is arranged so as not to disturb the connecting screws 16 .

Figs. 10a and 10b show a form and an arrangement of the cooling pipe 17 which is connected to the cooling plate 15. The cooling line 17 has an elliptical cross-sectional shape as shown in Fig. 10b. The cooling tube 17 is connected to the cooling plate 15 that a long axis of the ellipse is parallel to the cooling plate 15 , with a contact area being extended. The cooling line meanders without disturbing the fastening or connecting screws, thereby making the cooling line 17 long and extending the contact area with the cooling line 17 .

Figs. 11a to 11d show an arrangement of two cooling pipes 17 a and 17 b that are provided in order to reduce transmission losses of the cooling pipe 17. The two cooling lines 17 a, 17 b are arranged parallel to one another and completely over the cooling plate 15 , so that the entire surface of the cooling plate 15 is cooled with the cooling lines. The cooling line 17 a and 17 b are connected to distributors 18 at both ends, the distributors being connected to an inlet line 19 a and an outlet line 19 b, respectively.

The Fig. 12, 13 and 14 show a structure for further reducing pressure loss, and to enlarge the contact area by using a cooling tube 19 (eg. B. formed by extrusion) having multiple passageways. The cooling tube 19 is provided with mounting screw holes 20 . They are mounted on an inlet header 21 and an outlet header 22 at both ends. An inlet line 23 and an outlet line 24 is connected to the inlet and the outlet head piece 21 , 22 . In this construction, a heat conduction area for cooling increases fourfold, the pressure loss is reduced to 1/5, compared with the cooling line and its active power is greatly improved with a construction constructed in accordance with this. In addition, the strength of the cooling tube itself is quite strong and the cooling tube can serve as a base for mounting other components thereon.

As shown in FIG. 14, the cooling tube 19 has a plurality of coolant paths 25 , each of which has a rectangular cross section.

Fig. 15 shows a construction in which airtightness and pressure resistance can be maintained by providing a spacer 26 in a connecting portion of the Auslaßlei device 24 and the outlet header 22 .

Fig. 16 shows a construction in which the exhaust pipe 24 is expanded and connected to the exhaust header 22 without using the spacer 26 .

Figs. 17 to 21b show the cooling of the electric motor.

In Figs. 17 and 18 has an induction motor, a stator or a stator core 31, the AC electric power, and generates a rotating magneti ULTRASONIC field, a rotor 32 which is rotated by the rotating magnetic field, a shaft 33, the rotor the 32 carries, bearings 34 which support the shaft 33 and a carrier 35 which supports the bearings 34 . An outer ring 36 , in which passages for the coolant are formed, is mounted on the outer periphery of the stator 31 .

The outer ring 36 is formed by rounding plate-like drawn reduction material to fit the size of the outer periphery of the stator 31 , thereby forming the coolant passages in an annular shape.

The outer ring is press-fitted onto the stator 31 , the outer ring 36 being able to be firmly contacted with the stator 31 and the heat conduction and the cooling effect are improved. Furthermore, it is effective as a material for the outer ring 36, a softer material such. B. aluminum, copper to be used as an electromagnetic steel plate used for the rotor. This has the effect of increasing the fit of the outer ring 36 on the stator 31 because the outer ring 36 deforms when the outer ring 36 is press fit into the stator 31 . In addition, the fit can be further increased by forming a fine knurl on the outer circumference of the stator, as shown in FIGS. 19a, 19b, and cutting the outer circumference of the stator 31 into the outer ring 36 when the outer ring 36 is inserted by press fitting, a contact area can be enlarged.

As shown in Fig. 20, by providing the outer ring 36 with separate sides each extending in an axial direction and by providing an adjustable mechanism 36 c for adjusting a gap or a width between the separated sides, such as z. As bolts or nuts, the size of the contact area of the outer ring 36 with the stator 31 can be designed to be rough, and the fit or tight fit between the outer ring 36 and the stator 31 can be increased by a simple construction. 36 a represents an inlet or outlet.

Figs. 21a and 21b show an embodiment of the outer ring 36. The outer ring 36 has an inlet 36 a, i.e., a manifold section 36 which leave the A 36 a is connected, a plurality of parallel passage portions 36 b that are connected to the manifold section 36 d, a collector section (not shown ge, but similar in construction to the distributor section 36 d) and an outlet (not shown, but similar in construction to the inlet 36 a). The coolant from the inlet 36 a flows into the collector section 36 d to be distributed to each parallel passage section 36 b, flows into the parallel passage sections 36 b, is collected in a stream through the collector section, and then flows into the outlet. With this construction, the volume resistance of the coolant is reduced and a contact area between the coolant and the passage can be made larger, so that effective cooling can be effected.

In the case where it is unnecessary to consider the volume resistance for the coolant so strictly, it is considered that the coolant passage is wound directly on the outer periphery of the stator 31 in a spiral or zigzag manner. In this case, the cooling passage effectively has an elliptical or rectangular cross section. There are gaps between the stator and the cooling line mounted thereon, so that it is necessary to fill these gaps with good heat conductive resin. In addition, by forming the cooling pipe in a spiral or zigzag manner in advance and by making the inner diameter of the contact surface of the cooling pipe with the stator 31 smaller than the diameter of the outer periphery of the stator 31 , the assembled stator and the cooling pipe become excellent in their fit and the cooling effect.

The invention is explained with the above embodiments. According to the invention, a coolant does not become one freezing solution by the electric motor and the control device forcedly recirculated so that the cooling system of a motor vehicle can be obtained can, which is able to cool constantly regardless of the seasons.

There are also effects of supporting the heating of the automobile space and suppressing the reduction in battery power due to Heat retention through effective use of the heat in the engine or the control device is generated.  

There is also an effect that the electric motor and the control device can be effectively cooled with a simple construction.

Claims (12)

1. Cooling system for an electric vehicle with an electric motor ( 2 ) for generating the driving force, a control device ( 1 ) for controlling the electric motor ( 2 ) and a battery housing ( 7 ), the cooling system having a cooling circuit with a cooler ( 3 ) and a pump ( 4 ) for cooling the electric motor ( 2 ) and the control device ( 1 ), the cooling circuit comprising:
a first circulation line through which the cooler ( 3 ), the pump ( 4 ), the control device ( 1 ) and the electric motor ( 2 ) are connected to one another and in which a liquid coolant is circulated by the pump ( 4 ),
a second circulation line through which the pump ( 4 ), the control device ( 1 ), the electric motor ( 2 ) and the battery housing ( 7 ) are connected to one another and in which the coolant is circulated by the pump ( 4 ), and
a switching mechanism (V1, V2) for switching depending on a temperature condition from the first to the second circulation line and vice versa, wherein the second circulation line uses part of the first circulation line and wherein the coolant in the second circulation line circulates through the battery case ( 7 ) , which has been heated by the heat exchange on the electric motor ( 2 ) and the control device ( 1 ) in order to heat the battery housing ( 7 ) with the heated coolant when the outside air temperature is lower than a preset value. 2. Cooling system according to claim 1, wherein a battery is provided with the battery housing ( 7 ) having a cooling channel ( 71 ), and wherein the second order line comprises this cooling channel ( 71 ). 3. Cooling system according to claim 1 or 2, wherein the switching mechanism so is built up that part of the coolant in the first circulation line and other part of the coolant can circulate in the second circulation line. 4. Cooling system according to one of the preceding claims, further comprising a third circulation line for circulating the coolant through a heater ( 8 ) and a further switching device to circulate the coolant either through the battery housing ( 7 ) or the heater ( 8 ). 5. Cooling system according to one of the preceding claims, wherein the electric motor ( 2 ) is arranged on a downstream side of the control device ( 1 ). 6. Cooling system according to one of the preceding claims, wherein the control device ( 1 ) is provided with semiconductor components ( 10 ) which are arranged on one side of a cooling plate ( 15 ) by means of mounting plates ( 11 , 12 , 13 ), and wherein the cooling plate is provided with a cooling line ( 17 ) of the cooling circuit. 7. Cooling system according to claim 6, wherein the semiconductor components ( 10 ) are each assigned to one of three current phases (U, V, W) and are each mounted on a mounting plate ( 11 , 12 , 13 ). 8. Cooling system according to one of the preceding claims, wherein the elec tromotor ( 2 ) has a passage for the circulation of the coolant, which is formed in an outer ring ( 36 ) which in the outer periphery of a stator core ( 31 ) of the electric motor ( 2 ) is inserted by press fitting. 9. Cooling system according to claim 8, wherein the material of the outer ring ( 36 ) is softer than that of the stator core ( 31 ). 10. The cooling system of claim 8, wherein the stator core ( 31 ) has a knurled outer periphery. 11. Cooling system according to claim 8, wherein the outer ring ( 36 ) has an opening and its diameter can be adjusted by a mechanism ( 36 c). 12. The cooling system of claim 8, wherein the passageway has a construction in which the coolant entering an inlet ( 23 ) is distributed into a plurality of parallel passages ( 25 ) and in a flow at an outlet ( 24 ). is collected.