ELECTRIC OR HYBRID VEHICLE TRACTION SYSTEM COMPRISING TWO THERMAL CONTROL FLUID LOOPS

Abstract

Electric or hybrid vehicle traction system comprising a thermal control circuit having a first circulation loop (8) having a first fluid circulation pump (20), at least one cooler (22) or heater (24), a traction battery (26) and a first fluid distribution valve (6), having a second circulation loop (12) having a second fluid circulation pump (32), electrical components (34) including a traction machine, an external heat exchanger (38) and a second fluid distribution valve (10), the first loop (8) and the second loop (12) having different fluids, and a common drive unit (16) simultaneously actuating both distribution valves (6, 10). Figure 1

Description

Title of the invention: Traction system for electric or hybrid vehicles comprising two thermal regulation fluid loops

[0001] The present invention relates to an electric or hybrid vehicle traction system equipped with an electric traction machine, a battery supplying this machine, and a thermal regulation circuit comprising at least two fluid loops, as well as a method for managing this traction system and a vehicle comprising such a system.

[0002] A known type of thermal regulation system for an electric or hybrid vehicle, described in particular by document FR-A1-3078386, comprises a fluid circuit with three loops, each with a temperature range adapted for its components. Two multi-way distribution valves allow circulation between the loops of the same heat transfer fluid, comprising water with additives, in particular glycol forming an antifreeze, in order to regulate heat exchange to optimize the operation of each component while reducing overall energy consumption.

[0003] A first very low temperature loop includes the vehicle's traction battery, a cooler for the vehicle's air conditioning system and a circulation pump to maintain this battery at a low temperature, cooling it if necessary.

[0004] A second high-temperature loop includes a passenger compartment heat exchanger, an electric heater and a circulation pump to heat the passenger compartment from an electrical current consumption.

[0005] A third low-temperature loop includes the traction machine, its control inverter, a heat exchanger with the outside and a circulation pump to cool the machine and its inverter by dissipating heat into the ambient air.

[0006] The two distribution valves located at the junction of the loops allow exchanges of the same fluid between these loops, for example, depending on the operating conditions of the vehicle and its environment, to heat the passenger compartment from the heat released by the electric machine and its inverter or by the battery, or to cool the passenger compartment from the air conditioning system's cooler,

[0007] However, this type of thermal regulation system, which uses the same fluid to perform exchanges between loops, does not allow for optimization of the type of fluid used for each application. In particular, the traction battery includes electrochemical elements for storing electrical energy, which in the event of an incident in the battery compartment can lead to fire risks that are difficult to extinguish.

[0008] Moreover, the different valves for each loop with their independent motors pose problems of increased number of components, increased complexity of the automatic controls of the whole, and add bulk, mass and costs to the vehicle.

[0009] The present invention aims in particular to avoid these problems of the prior art.

[0010] To this end, it proposes a traction system for an electric or hybrid vehicle comprising a thermal regulation circuit having a first circulation loop having a first fluid circulation pump, at least one cooler or heater, a traction battery and a first fluid distribution valve, having a second circulation loop having a second fluid circulation pump, electrical components including a traction machine, a heat exchanger to the outside and a second fluid distribution valve, this system being remarkable in that the first loop and the second loop have different fluids, and in that a common motor simultaneously actuates the two distribution valves.

[0011] An advantage of this traction system is that it allows for the provision of a suitable fluid for each loop, in particular for the first loop a fluid with specific characteristics limiting the risks of accidents in the battery, which is different from the fluid of the second loop intended to circulate more easily in the traction machine and its control electronics.

[0012] Moreover, despite the two separate loops, each with its own valve distributing its own fluid, greater complexity of the traction system is avoided thanks to the single motorization operating both valves at the same time.

[0013] The vehicle traction system according to the invention may further comprise one or more of the following characteristics, which may be combined with each other.

[0014] Advantageously, the two distribution valves have the same drive shaft receiving a sealing gasket between these two valves.

[0015] Advantageously, the first circulation loop comprises a dielectric fluid and the second circulation loop comprises water with added glycol.

[0016] Advantageously, the second circulation loop includes in series a heat exchanger between the fluids of the two loops, which, depending on the position of the first valve, also receives the fluid from the first loop.

[0017] Advantageously, the first loop includes a direct path which allows the passage of fluid into the battery to be short-circuited.

[0018] Advantageously, the second loop includes a direct path which allows bypass the flow of fluid through the external heat exchanger.

[0019] The invention also relates to a method of operating a traction system comprising any one of the preceding characteristics, remarkable in that in a first position of the common motorization the two loops operate independently without heat exchange between them.

[0020] The invention further relates to a method of operating a traction system comprising any one of the preceding characteristics, remarkable in that in a second position of the common motorization the first loop operates by short-circuiting the battery with the direct path of the first loop, and the second loop operates independently without heat exchange with this first loop.

[0021] The invention further relates to a method of operating a traction system comprising any one of the preceding characteristics, the second circulation loop having in series a heat exchanger between the fluids of the two loops, remarkable in that in a third position of the common motorization the two loops exchange heat through this heat exchanger.

[0022] The invention further relates to an electric or hybrid motor vehicle, equipped with a traction system comprising any of the preceding characteristics, which also provides heating or cooling of the passenger compartment.

[0023] The invention will be better understood and other features and advantages will become more apparent upon reading the following description given by way of example, with reference to the accompanying drawings in which:

[0024] [Fig. 1] is a diagram of the thermal regulation circuit of a traction system according to the invention showing the two loops;

[0025] [Fig.2] presents this scheme in a first operating mode independent of the two loops with thermal regulation of the battery;

[0026] [Fig.3] presents this scheme in a second independent operating mode of the two loops without thermal regulation of the battery; and

[0027] [Fig.4] presents this scheme in a third combined operating mode of the two loops with heat exchange between them.

[0028] Fig. 1 presents the thermal regulation circuit of a traction system of an electric or hybrid motor vehicle, with two separate fluid loops receiving different heat transfer fluids, comprising a first loop 8 at very low temperature controlled by a first distribution valve 6, and a second loop 12 at low temperature controlled by a second distribution valve 10.

[0029] The two valves 6, 10 comprise a common shaft 4 actuated in rotation by a unique motorization 16 of these valves, supporting the two plugs which rotate at the same time, with a dynamic sealing joint 14 clamping the shaft, interposed axially between the two plugs to avoid fluid exchanges between them.

[0030] The first fluid loop 8 comprises successively, starting from the first valve 6, a first circulation pump 20, a cooler 22 and an electric heater 24 which is also part of the vehicle's passenger compartment air conditioning system, then a battery 26 supplying an electric traction machine for the vehicle.

[0031] After the heater 24 of the first loop 8, a direct return path 28 arranged in parallel with the battery 26 allows the fluid to return directly to the first valve 6 by short-circuiting this battery.

[0032] The first fluid loop 8 also includes, starting from the first valve 6, a supply 40 to a heat exchanger between the fluids of the two loops 30, then a return 42 from this exchanger to the first valve.

[0033] The second fluid loop 12 comprises successively, starting from the second valve 10, the heat exchanger between the two different fluids of the loops 30, a fluid circulation pump 32, then a set of electrical components 34 including the electric traction machine, its power inverter and a battery charger from an external electricity distribution network.

[0034] After the set of electrical components 34, the second loop 12 includes a direct return path 36 to the second valve 10, and in parallel a heat exchanger with the outside 38 then returning to this second valve.

[0035] The heat transfer fluid of the second loop 12 comprising the electric traction machine is water with added glycol and other additives, commonly used in vehicle cooling circuits, which provides both high fluidity facilitating the work of the second circulation pump 32 which may have low power, and a significant thermal capacity.

[0036] The heat transfer fluid of the first loop 8 is a dielectric fluid, ensuring good thermal conductivity and electrical insulation, which flows through heat exchange plates of the traction battery 26 in contact with the electrochemical energy storage cells to cool them. In the event of a leak of the dielectric fluid in the battery casing 26, the electrical insulation properties of this fluid provide additional safety by preventing short circuits with the electrochemical cells or with the high-voltage connections in the casing, thus reducing the risk of fire.

[0037] However, the dielectric fluid of the first loop 8 is more viscous than water with added glycol, which requires more power for the circulation pump 20, and is more corrosive, which necessitates an adaptation of the components. receiving.

[0038] The two fluid loops 8, 12 operate with their own separate heat transfer fluids, with the possibility of heat exchange between them through the fluid exchanger 30. The common drive 16 of the valves 6, 10 allows, with the rotation of the common shaft 4, to obtain different angular positions of the plugs of the two valves, including at least three operating positions.

[0039] Fig. 2 shows, with the first position of the motorization 16, the operation of the two loops 8, 12 independently, without heat exchange between them.

[0040] In the first loop 8, the circulation of the dielectric fluid generated by the first pump 20 allows the battery 26 to be heated using the heater 24, for example when starting the vehicle with a cold outside temperature, or the battery to be cooled using the cooler 22. In the second loop 12, the facilitated circulation of the glycol water, which is very fluid, by the second pump 32, allows the electrical components 34 to be cooled, which then dissipates the heat in the external heat exchanger 38.

[0041] Figure 3 shows, with the second position of the motor 16, the operation of the two loops 8 and 12, which are also independent. The second loop 12 exhibits the same autonomous operation.

[0042] The first loop 8 uses the first direct return path 28 so as not to pass through the battery 26, the fluid passing only through the cooler 22 and the heater 24.

[0043] Fig. 4 shows, with the third position of the motorization 16, an exchange of thermal energy between the two loops 8, 12, thanks to a passage of the first loop through the heat exchanger between fluids 30 which allows a transfer of calories between the dielectric fluid and the glycol water.

[0044] In this case, the second direct return path 36 is used at the output of the electrical components 34 which have heated the fluid of the first loop 8, to pass into the heat exchanger between fluids 30 which transmits its calories to the dielectric fluid in order to heat the battery 26 in turn.

[0045] In this way, particularly for cold starts of the vehicle, the battery 26 is heated in order to improve its operating characteristics without consuming electrical current in the heater 24.

[0046] The different positions of the valves 6, 10 are achieved by means of a motor 16 comprising a single motor with its control, which simplifies the thermal regulation circuit control system, reduces the number of components, decreases the vehicle's mass, and lowers manufacturing costs. Furthermore, the nature of the fluids in the two loops 8, 12 is optimized to improve safety in battery 26, while maintaining easy fluid circulation in the second loop 12 which remains very fluid.

Claims

Demands

1. Electric or hybrid vehicle traction system comprising a thermal control circuit having a first circulation loop (8) having a first fluid circulation pump (20), at least one cooler (22) or heater (24), a traction battery (26) and a first fluid distribution valve (6), having a second circulation loop (12) having a second fluid circulation pump (32), electrical components (34) including a traction machine, an external heat exchanger (38) and a second fluid distribution valve (10), characterized in that the first loop (8) and the second loop (12) have different fluids, and in that a common motor (16) simultaneously actuates both distribution valves (6, 10).

2. Traction system according to claim 1, characterized in that the two distribution valves (6, 10) have the same drive shaft (4) receiving a sealing gasket (14) between these two valves (6, 10).

3. Traction system according to claim 1 or 2, characterized in that the first circulation loop (8) comprises a dielectric fluid and the second circulation loop (12) comprises water with added glycol.

4. Traction system according to any one of the preceding claims, characterized in that the second circulation loop (12) includes in series a heat exchanger (30) between the fluids of the two loops (8, 12), which depending on the position of the first valve (6) also receives the fluid from the first loop (8).

5. Traction system according to any one of the preceding claims, characterized in that the first loop (8) comprises a direct return path (28) which allows the passage of fluid through the battery (26) to be short-circuited,

6. Traction system according to any one of the preceding claims, characterized in that the second loop (12) has a direct return path (36) which allows the passage of the fluid in the external heat exchanger (38) to be short-circuited.

7. A method of operating a traction system according to any one of the preceding claims, characterized in that in a first position of the common motorization (16) the two loops (8, 12) operate independently without heat exchange between them.

8. Method of operating a traction system according to any one of claims 1 to 6, characterized in that in a second position of the common motorization (16) the first loop (8) operates by short-circuiting the battery (26) with the direct path of the first loop (28), and the second loop (12) operates independently without heat exchange with this first loop (16).

9. Method of operating a traction system according to any one of claims 1 to 6, the second circulation loop (12) comprising in series a heat exchanger (30) between the fluids of the two loops (8, 12), characterized in that in a third position of the common drive (16) the two loops exchange heat through this heat exchanger (30).

10. Electric or hybrid motor vehicle, characterized in that it comprises a traction system according to any one of claims 1 to 6, also providing heating or cooling of the passenger compartment.

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