Drive system for electric vehicle and electric vehicle

Abstract

To provide a drive system for an electric vehicle, and also to provide an electric vehicle.SOLUTION: A drive system according to the present invention is a drive system (10) for an electric vehicle (100) and includes, as drive configuration elements, a traction battery (12), an inverter (14), and an electrical machine (16). The drive system is formed so that the traction battery is electrically connected to the electrical machine via the inverter, and so that the traction battery is electrically connected to the inverter via respective high voltage connection elements (22, 24), and so that the inverter is electrically connected to the electrical machine. The drive system includes a cooling circuit (26) for cooling the drive configuration elements by a cooling medium (28). The drive system is formed so that the respective drive configuration elements and high voltage connection elements transport the cooling medium and are formed to form a part (30) of the cooling circuit.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a drive system for an electric vehicle. [Background technology]

[0002] Patent Document 1 discloses a configuration of multiple electric vehicle drive components including a battery, an electric machine, an inverter, a cable core for conducting a high current, and a high current cable having a coolant channel between the cable sheath and the cable core. The vehicle drive components are connected to multiple cooling circuits, and these cooling circuits need to be operated for cooling.

[0003] Patent Document 2 discloses a drive system for an electric vehicle, which includes a battery, an inverter, and an electric machine. A cooling device is also provided, which can cool the converter and the electric machine. Other components are not cooled. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] DE 10 2019 205 466 A1 [Patent Document 2] DE 10 2019 103 735 A1 Summary of the Invention [Problem to be solved by the invention]

[0005] SUMMARY OF THE DISCLOSURE It is an object of the present invention to provide an improved drive system in accordance with the above. [Means for solving the problem]

[0006] This object is achieved by a drive system as claimed in claim 1.

[0007] A drive system for an electric vehicle comprises as drive components a traction battery, an inverter and an electric machine. The traction battery is electrically connected to the electric machine via the inverter, whereby the traction battery is electrically connected to the inverter (DC voltage side) and the inverter is electrically connected to the electric machine (AC voltage side) by respective high-voltage connection elements. The drive system comprises a cooling circuit for cooling the drive components by means of a cooling medium, preferably a liquid, whereby the drive components and the high-voltage connection elements are each formed to convey the cooling medium and (together) form at least a part of the cooling circuit.

[0008] That is, the drive component and the high voltage connection element are each formed in such a way that they can transport a cooling medium. In particular, the drive component and the high voltage connection element each have a channel section for transporting the cooling medium. In the assembled state (drive component and high voltage connection element are coupled to each other), the channel section forms a cooling medium channel and thus a part of the cooling circuit. Thus, the current- and power-conducting drive component and the high voltage connection element also transport the cooling medium.

[0009] In other words, the current conducting line cores of the drive components and the high voltage connection elements run alongside one another, for example in a parallel arrangement, together with the channel sections for the cooling medium from the traction battery, through the electrical high voltage connection elements between the traction battery and the inverter, through the inverter, through the further high voltage connection elements between the inverter and the electric machine and further through the electric machine. The cooling paths thus run together with the current or power paths. This contributes to an optimized and uniform cooling of the drive components using simply designed means.

[0010] High voltage connection elements are intended to be capable of transmitting not only high voltages (e.g., 400-800 volts) but also high currents (e.g., 250-600 or 900 amperes), and therefore are sometimes also referred to as high current connection elements.

[0011] The electric vehicle is in particular a motor vehicle, such as an electric passenger car or commercial vehicle. The drive system is used as a traction drive for the electric vehicle. The inverter may in particular be a pulse inverter. Preferably, a liquid cooling medium, such as water or oil, can be used as the cooling medium.

[0012] A charging line may be connected to the traction battery, electrically connecting the traction battery to a charging socket (such as is provided on the electric vehicle). The charging line may be connected to a cooling circuit and thus cooled.

[0013] Preferably, the high-voltage connection elements can be configured as high-voltage lines (single-wire or multi-wire high-voltage cables), plug connectors, busbars or screws, respectively, which allow the transmission of sufficiently large currents according to the respective requirements.

[0014] Preferably, each high-voltage connection element has a sheath surrounding the outside of the respective high-voltage connection element, and a channel section, through which the cooling medium is conveyed, is formed in the intermediate space between the sheath and the high-voltage connection element, which allows a large amount of heat to be transferred in the case of a compact design.

[0015] Preferably, the drive component and the high-voltage connection element each have a connection interface for coupling the drive component to the high-voltage connection element, the connection interface having in each case an electrical connection (for power or current conduction) and a fluid connection (for conveying a cooling medium). Thus, the electrical and fluid connections are integrated in the connection interface. By connecting the connection interfaces, the associated drive component and the high-voltage connection element are electrically and fluidly connected to each other.

[0016] Preferably, parts of the drive components and the high-voltage connection elements, or all of the drive components and the high-voltage connection elements, can be formed in such a way that they are or can be cooled by a cooling medium by direct cooling. Thus, the cooling medium can be flowed directly around areas or regions of the drive components and the high-voltage connection elements that have particularly high cooling requirements. For this purpose, the areas or regions can be fluidly connected to a cooling circuit or a cooling medium channel.

[0017] Preferably, a heat exchanger or cooler for controlling the temperature of the cooling medium can be connected in the cooling circuit upstream of the traction battery (in the direction of circulation of the cooling circuit or cooling medium), so that heat can be transferred between the cooling medium of the cooling circuit and the surroundings of the drive system. Thus, for example, thermal energy absorbed by the cooling medium can be released to the surroundings by the heat exchanger.

[0018] Preferably, the drive system can have a gear mechanism as a further drive component, in particular coupled and connected to the electric machine downstream of the electric machine, the gear mechanism having a gear mechanism heat exchanger, which is integrated into the cooling circuit. The gear mechanism heat exchanger can be connected downstream of the electric machine in a circulation direction of the cooling circuit or the cooling medium. The temperature of the gear mechanism oil can be controlled using a heated cooling medium, by the cooling medium of the cooling circuit passing through the gear mechanism heat exchanger. The cooling medium of the entire drive system can release heat to the gear mechanism oil by the gear mechanism heat exchanger. As a result, the efficiency of the gear mechanism can be increased. Alternatively or additionally, the gear mechanism or the gear mechanism oil can be cooled by the cooling circuit.

[0019] Preferably, the drive system can comprise at least two inverters, at least two electric machines and at least two gear mechanisms with gear mechanism heat exchangers, in each case one inverter, one electric machine and one gear mechanism with gear mechanism heat exchanger combined to form a drive module. The drive system thus has two or more drive modules, by means of which for example individual wheel drives can be realized. For example, there can be one to two drive modules for driving a first axle (for example the front axle) and / or one to two drive modules for driving a second axle (for example the rear axle). The cooling circuit can then be split into two or more substreams, after flowing, for example, through a traction battery, each substream flowing through a respective drive module. In this case, the substreams each flow through the inverter, the electric machine and the gear mechanism heat exchanger of the associated gear mechanism. After passing through the gear mechanism heat exchanger, two or more substreams of the cooling circuit can be combined to form one stream again. The drive modules can be supplied with energy by a common traction battery or each have their own battery.

[0020] Preferably, a pump for conveying the cooling medium can be connected upstream of the traction battery in the cooling circuit, so that it is possible to ensure the conveyance of the cooling medium, for example by increasing the pressure level of the cooling medium before it enters the traction battery. The pump is in particular connected immediately upstream of the traction battery.

[0021] Preferably, a (further) pump for conveying the cooling medium can be connected upstream of the electric machine in the cooling circuit. This also contributes to a reliable conveying of the cooling medium, for example by increasing the pressure level of the cooling medium before it enters the electric machine. The further pump is in particular connected immediately upstream of the electric machine.

[0022] The cooling circuit may preferably be the only cooling circuit of the drive system, in other words all drive components and electrical high voltage connection elements are integrated into the cooling circuit and are temperature controlled or cooled by said cooling circuit. By having only one cooling circuit in the drive system the number and complexity of components is reduced.

[0023] Preferably, the cooling circuit can have only one cooling medium, which contributes to simplifying the structure of the cooling circuit and reducing the complexity of the cooling circuit, since only one cooling medium needs to be provided and transported in the cooling circuit.

[0024] Preferably, one, several or all of the drive components can be fluidly connected to the cooling circuit respectively by a controllable switching valve. Thus, depending on the cooling requirements, each drive component can be connected to the cooling circuit (e.g. opening the switching valve) or disconnected from the cooling circuit (e.g. closing the switching valve). Thus, an optimal and need-based thermal management of the drive system and the vehicle as a whole can be achieved. In each case, the drive components can be provided with a bypass line that can be fluidly connected to the cooling circuit. For example, when a switching valve at one of the drive components is closed, the cooling circuit can bypass that drive component and flow through the drive component that follows, for example in the flow direction.

[0025] Preferably, one or more heat exchange devices (heat exchangers or technical auxiliary systems) can be provided, each with a first side integrated into the cooling circuit and a second side of the heat exchange device having a heat discharge connection for discharging thermal energy, in particular to the interior of the vehicle cabin or electric vehicle. Thus, it is possible to advantageously integrate an interior air conditioning system into the cooling circuit. For example, the exhaust heat of the drive system or one or more drive components can be used to heat the interior of the vehicle cabin.

[0026] The object stated at the outset is also achieved by an electric vehicle comprising a drive system having one or more of the above-mentioned aspects, in which respect reference is made to the description of the drive system for the advantages.

[0027] The measures mentioned above in relation to the drive system and / or further described below serve to further improve electric vehicles.

[0028] Further advantageous configurations will become apparent from the following description and the drawings. [Brief description of the drawings]

[0029] [Figure 1] FIG. 2 is a basic circuit diagram of a drive system. [Diagram 2] FIG. 2 is a partial cross-sectional side view of a portion of the drive system. [Diagram 3] FIG. 1 is a schematic diagram of a drive system configuration having multiple drive modules. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] Figure 1 shows, in a simplified manner, a basic circuit diagram of a drive system 10 for an electric vehicle 100. Figure 1 also shows the electric vehicle 100 equipped with such a drive system 10. The drive system 10 is described below.

[0031] The drive system 10 includes as drive components a traction battery 12, an inverter 14, and an electric machine 16. The traction battery 12 is electrically connected to the electric machine 16 via the inverter 14. The inverter 14 has a DC voltage side 18 and an AC voltage side 20. The traction battery 12 is electrically connected to the inverter 14, and the inverter 14 is electrically connected to the electric machine 16 by high voltage connection elements 22, 24, respectively.

[0032] The drive system 10 has a cooling circuit 26 for cooling the drive components with a cooling medium 28, preferably liquid, where the drive components (traction battery 12, inverter 14, electric machine 16) and the high-voltage connection elements 22, 24 are each configured to carry the cooling medium and together form a part 30 of the cooling circuit 26.

[0033] The drive components (traction battery 12, inverter 14, electric machine 16) and the high-voltage connection elements 22, 24 each have a power- or current-conducting line core L and a channel section K for conveying a cooling medium 28. The line core L and the channel section K run adjacent to one another, in particular parallel to one another, through the traction battery 12, the high-voltage connection element 22, the inverter 14, the high-voltage connection element 24 and further through the electric machine 16.

[0034] In this example, the high voltage connection element 22 is formed as a multi-wire high voltage line (not shown). The high voltage connection element 24 can be formed as a multi-wire high voltage line, a plug connector, a bus bar, or a screw (not shown).

[0035] As already indicated, each high voltage connection element 22, 24 has a power or current conducting line core L and a channel section K for carrying the cooling medium 28. To form the channel section K, each high voltage connection element 22, 24 has a sheath surrounding the outside of the respective high voltage connection element 22, 24, and the channel section K for the cooling medium 28 (not shown) is formed in the intermediate space between the sheath and the high voltage connection element 22, 24 or the line core L.

[0036] The drive components and high voltage connection elements 22, 24 each have a connection interface 32, 34 (shown only once in FIG. 1 for clarity) for coupling the drive components to the high voltage connection elements 22, 24, and the connection interfaces 32, 34 each have an electrical connection (for conducting power or current) and a fluid connection (for transporting the cooling medium 28) (not shown).

[0037] Preferably, some of the drive components and high voltage connection elements 22, 24, or all of the drive components (traction battery 12, inverter 14, electric machine 16) and the high voltage connection elements 22, 24 can be formed such that they are or can be cooled by the cooling medium 28 by direct cooling. Thus, the cooling medium 28 can flow directly around areas or regions with particularly high cooling requirements.

[0038] In this example, a cooler or heat exchanger 36 for controlling the temperature of the cooling medium 28 is connected in the cooling circuit 26 upstream of the traction battery 12 in the circulation direction U of the cooling circuit 26 or the cooling medium 28 .

[0039] In this example, the drive system 10 can have, as a further drive component, a gear mechanism 40 coupled to the electric machine 16 and connected downstream of the electric machine 16 (see FIG. 2 ), the gear mechanism 40 having a gear mechanism heat exchanger 42, which is integrated into the cooling circuit 26 (see FIG. 1 ). In this example, the gear mechanism heat exchanger 42 is connected downstream of the electric machine 16 in the circuit direction of the cooling circuit 26 or the cooling medium 28.

[0040] In this example, a pump 44 for conveying the cooling medium 28 is connected in the cooling circuit 26 upstream, in particular directly upstream, of the traction battery 12. In this example, a further pump 46 for conveying the cooling medium 28 is connected in the cooling circuit 26 upstream of the electric machine 16.

[0041] In this example, the illustrated cooling circuit 26 is the only cooling circuit of the drive system 10. The drive components (traction battery 12, inverter 14, electric machine 16, gear mechanism 40) and the electrical high-voltage connection elements 22, 24 are all integrated into the cooling circuit 26 and are therefore temperature controlled or cooled by the cooling circuit 26. In this example, the cooling circuit 26 has only one cooling medium 28.

[0042] FIG. 2 shows a partial cross-sectional side view of drive system 10 with only inverter 14, electric machine 16, gear train 40, and a portion of cooling circuit 26 shown for clarity.

[0043] The connection interface 34 is located on the DC voltage side 18 of the inverter 14, the connection interface 34 having an electrical connection 50 or L (for power or current conduction) and a fluid connection 52 or K (for conveying the cooling medium 28), respectively. A further connection interface 34' having an electrical connection 50' and a fluid connection 52' is formed on the AC voltage side 20. The high voltage connection element 24 is formed to the electrical connection 50', for example by a busbar. The cooling medium 28 is transported to the electric machine 16 in the fluid connection 52'.

[0044] The inverter 14 has a housing 54 with a top closing cover 56. A cooling structure 58, e.g. for carrier plates and / or electrical components of active parts 60 of the inverter 14, is arranged in the housing 54 and through which the cooling medium 28 flows.

[0045] Similarly, the cooling medium 28 flows through the electric machine 16, entering the electric machine 16 at an inlet 62 and exiting the electric machine 16 at an outlet 64. The electric machine 16 may have a stator cooling system, for example a direct stator cooling system. After exiting the outlet 64, the cooling medium 28 flows through the gear mechanism heat exchanger 42.

[0046] 3 shows the configuration of the drive system 10, which has two inverters 14, 14', two electric machines 16, 16', and two gear mechanisms 40, 40' with gear mechanism heat exchangers 42, 42', and one inverter 14, 14', one electric machine 16, 16', and one gear mechanism 40, 40' with gear mechanism heat exchangers 42, 42' are combined to form a drive module 70, 70'. Thus, the drive system 10 has two drive modules 70, 70', and the drive modules 70, 70' can realize individual wheel drive.

[0047] In this example, both drive modules 70, 70' are supplied with electrical energy by the traction battery 12. In this example, a charging line 80 is connected to the traction battery 12 (not shown), electrically connecting the traction battery 12 to a charging socket of the electric vehicle 100. The charging line 80 is connected to the cooling circuit 26 and is therefore cooled. The charging line 80 has a current-conducting or power-conducting line core L and a channel section K for the cooling medium 28.

[0048] The cooling medium 28 enters the traction battery 12 at an inlet 82 (e.g., coming from the heat exchanger 36), flows through the traction battery, and then splits into two sub-streams 84, 86, each of which is delivered to a drive module 70, 70'.

[0049] High voltage connection elements 22, 22' each having a current or power conducting line core L and a channel section K for a cooling medium 28 electrically and hydraulically connect the traction battery 12 to the inverter 14, 14' (DC voltage side 18).

[0050] Each sub-stream 84, 86 flows through a respective drive module 70, 70' and in each case the cooling medium 28 passes through the inverter 14, 14', the electric machine 16, 16', and the gear train heat exchanger 42, 42'. In the inverter 14, 14', the cooling medium 28 flows through a respective cooling structure 58, 58'.

[0051] High voltage connection elements 24, 24' electrically connecting the inverters 14, 14' to the electric machines 16, 16', respectively, are formed by busbars on the AC voltage side 20. There, the cooling medium 28 is also transported to the electric machine 16, where it is used to cool the stators 17, 17'.

[0052] The cooling medium 28 then exits the electric machine 16, 16' and is delivered to the gear mechanism heat exchanger 42, 42' of the gear mechanism 40, 40' in each case. After passing through the gear mechanism heat exchanger 42, 42', the two substreams 84, 86 of the cooling circuit 26 can be combined, if desired, to form one stream which is delivered back to the heat exchanger 36.

[0053] As explained above, one, several or all of the drive components may each be connected to the cooling circuit 26 by a controllable switching valve (not shown). Thus, each drive component may be connected to or disconnected from the cooling circuit depending on the cooling requirements.

[0054] Optionally, one or more heat exchange devices are provided, each with a first side integrated into the cooling circuit 26 and a second side having a heat discharge connection for discharging thermal energy (not shown). Thus, the waste heat of one or more drive components can be used to heat the interior of the vehicle. [Explanation of symbols]

[0055] 10 Drive System 12 Traction battery 14, 14' Inverter 16, 16' Electrical Machine 22, 22' High voltage connection element 24, 24' High Voltage Connection Element 26 Cooling circuit 28 Cooling medium 30 Part of the cooling circuit 26 32, 34 Connection interface 36 Heat exchanger 40, 40' Gear mechanism 42, 42' Gear mechanism heat exchanger 44 Pump 46 Pump 50, 50' Electrical Connection 52, 52' Fluid Connection 70, 70' Drive Module 100 Electric Vehicles

Claims

1. A drive system (10) for an electric vehicle (100), comprising a traction battery (12), an inverter (14, 14') and an electric machine (16, 16') as drive components, the traction battery (12, 12') being electrically connected to the electric machine (16, 16') via the inverter (14, 14'), and the traction battery (12) being connected to the inverter (14), the electric machine (16, 16') via high-voltage connection elements (22, 22'; 24, 24'), respectively. a drive system (10) electrically connected to an inverter (14, 14') and the inverter (14, 14') electrically connected to the electric machine (16, 16'), the drive system (10) comprising a cooling circuit (26) for cooling the drive components by a cooling medium (28), the drive components and the high voltage connection elements (22, 22'; 24, 24') being each configured to convey the cooling medium and to form a part (30) of the cooling circuit (26); the traction battery (12), the inverter (14), the electric machine (16) and the high-voltage connection elements (22, 24) each have a power conducting line core (L) and a channel section (K) for conveying the cooling medium (28), the power conducting line core (L) and the channel section (K) extending through connection interfaces (32, 34) incorporating electrical and fluid connections for coupling each of the traction battery (12), the high-voltage connection elements (22), the inverter (14), the high-voltage connection elements (24) and the electric machine (16) as well as each of the drive components (12, 14, 16) to each of the high-voltage connection elements (22, 22'; 24, 24'); the channel section (K) is formed in an intermediate space between a sheath and the power conducting line core (L) at least in a portion extending from the traction battery (12) through the connection interface (34) to the inverter (14).

2. 2. The drive system (10) of claim 1, wherein the drive components and some of the high voltage connection elements (22, 22'; 24, 24') or the entire drive components and the high voltage connection elements (22, 22'; 24, 24') are formed so as to be coolable by the cooling medium (28) by direct cooling.

3. 3. The drive system (10) according to claim 1 or 2, characterized in that a heat exchanger (36) for controlling the temperature of the cooling medium (28) is connected in the cooling circuit (26) upstream of the traction battery (12).

4. 4. The drive system (10) according to claim 1, characterized in that as a further drive component, the drive system (10) comprises at least one gear mechanism (40, 40') coupled to the electric machine (16, 16'), the gear mechanism (40, 40') having a gear mechanism heat exchanger (42, 42'), the gear mechanism heat exchanger (42, 42') being integrated into the cooling circuit (26).

5. 5. The drive system (10) according to claim 4, characterized in that the drive system (10) comprises at least two inverters (14, 14'), at least two electric machines (16, 16') and at least two gear mechanisms (40, 40') having gear mechanism heat exchangers (42, 42'), and one inverter (14, 14'), one electric machine (16, 16') and one gear mechanism (40, 40') having a gear mechanism heat exchanger (42, 42') are respectively combined to form a drive module (70, 70').

6. 6. The drive system (10) according to claim 1, characterized in that a pump (44) for conveying the cooling medium (28) is connected in the cooling circuit (26) upstream of the traction battery (12) and / or a pump (46) for conveying the cooling medium (28) is connected in the cooling circuit (26) upstream of the electric machine (16, 16').

7. The drive system (10) of any one of claims 1 to 6, characterized in that the cooling circuit (26) is the only cooling circuit of the drive system (10) and / or the cooling circuit (26) has only one cooling medium (28).

8. A drive system (10) according to any one of the preceding claims, characterized in that one, several or all of the drive components are respectively connected to the cooling circuit (26) by controllable switching valves.

9. A drive system (10) according to any one of the preceding claims, characterized in that one or more heat exchange devices are provided, each having a first side integrated into the cooling circuit (26) and a second side having a heat discharge connection for discharging thermal energy.

10. An electric vehicle (100) comprising a drive system (10) according to any one of the preceding claims.

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