Heating element for tempering flowing liquid and liquid circuit with heating element arranged therein

Abstract

A liquid circuit (22) for temperature control of a liquid-cooled battery unit (16) of a drive and energy supply unit (10) of a vehicle drive (14) is disclosed. The liquid in the liquid circuit (22) is circulated by means of a pump (24) and conveyed through the liquid-cooled battery unit (16). In a defined flow section (32) of the liquid circuit (22), at least one electrically operated heating element (28) is located, which is equipped with flow channels (54) whose channel walls are designed as planar heating conductors (44). Furthermore, a heating element (28) for forming a flow section (32) for a liquid circuit (22) intended for thermal exchange with a drive battery (16) is disclosed. The heating element (28) comprises at least one electrical heating conductor (44) and a support (46) on which the at least one electrical heating conductor (44) is arranged. The support (46) is a support layer or support film (48) which is wound spirally around a longitudinal central axis (42) of the heating element (28), wherein a flow channel (54) or several flow channels (54) for liquid are provided between regions of the support layer or support film (48) that are spaced apart from each other in the radial direction.

Description

[0001] The present invention relates to a heating element for forming a flow section for a liquid circuit intended for thermal exchange with a traction battery. The invention further relates to a liquid circuit with a heating element arranged therein and through which liquid flows.

[0002] Known drive and energy supply units for electric vehicle propulsion, where electrical power for one or more electric drive motors is provided by rechargeable battery or accumulator units, generally require a more or less comprehensive energy management system. This energy management system, which not only controls or regulates the delivered drive power according to the driver's current demand but also manages recuperation processes to recover electrical energy during braking or coasting, sensibly incorporates a thermal component, as the accumulators exhibit their highest performance in a temperature range above 15°C, but not too high, preferably below 30°C.

[0003] Since the battery units used for vehicle propulsion are subjected to high stresses both during charging and when used as an electrical energy source for the drive motors, temperature control is generally advisable. Particularly at cold temperatures, the electrical performance and available capacity of the battery cells used in the battery units decrease significantly, making rapid warming before and during driving desirable.

[0004] Since the need for rapid cooling when battery units heat up significantly generally requires liquid cooling, this cooling circuit is also fundamentally available for temperature control of the battery units at cold ambient temperatures. Typically, electric heating elements, similar to immersion heaters, can be used for this purpose. These can be, for example, electrically heated metal heating coils that are surrounded by the circulating fluid and can thus heat the fluid as needed.

[0005] Since such heating devices operate relatively inaccurately and can only be controlled and regulated with a certain inertia, precise and rapid temperature control of the liquid cannot usually be achieved.

[0006] In view of these identified disadvantages, the object of the invention can be considered to be to provide an effectively operating and easily controllable heating element for a liquid circuit with which a battery unit can be effectively temperature controlled, in particular within a power supply unit used for an electric vehicle drive.

[0007] This objective of the invention is achieved by the subject matter of the independent claims. Features of advantageous embodiments of the invention are described in the respective dependent claims.

[0008] To achieve this objective, the invention proposes a heating element for forming a flow section for a liquid circuit intended for thermal exchange with a traction battery, wherein the heating element according to the invention comprises at least one electrical heating conductor and a support, the at least one electrical heating conductor being arranged on this support. The support is provided to be a carrier layer or carrier film which is wound or coiled spirally around a longitudinal central axis of the heating element, wherein a flow channel or several flow channels for liquid are provided between regions of the carrier layer or carrier film that are spaced apart from each other in the radial direction.

[0009] The heating element can be equipped, in particular, with a cylindrical housing that accommodates the electrical heating conductor. The electrical heating conductor can preferably be equipped with a plurality of flow channels through which the fluid to be heated can flow, essentially parallel to the longitudinal central axis of the housing (which is particularly cylindrical) or of the heating conductor.

[0010] The flow channels of the heating element according to the invention preferably extend through the longitudinal direction of the heating conductor with approximately constant cross-sections. The heating element is suitable as a heating device that can be controlled quickly and precisely, since at least sections of the channel walls of the flow channels are designed as heatable surfaces that can effect a rapid and effective heat transfer as the liquid flows from the heating conductor to the liquid.

[0011] Optionally, the heated surfaces of the flow channels can extend over the entire length of the respective flow channels.

[0012] However, embodiments of the electric heating element are also conceivable in which the heatable surfaces of the flow channels can have separately controllable areas along their longitudinal extent, which can be separated from one another and subjected to different temperatures. These separately controllable areas can, for example, be formed by separate sections of the planar heating conductors.

[0013] In principle, it is advantageous if the numerous channels of the heating element each have similar cross-sections from an inlet end face to an outlet end face of the heating element, as this prevents any significant flow disturbances for the liquid conveyed by the heating element.

[0014] The heating element according to the invention can, for example, comprise a wound planar heating conductor equipped with a corrugated cover layer which is applied in regular line contact to a first planar sub-layer and thus forms the regularly spaced flow channels between the two layers.

[0015] Alternatively, both the first planar sublayer and the wavy top layer can be coated with an electrically conductive material, at least on their facing surfaces, and designed as a tempering surface.

[0016] Alternatively, both the first flat sub-layer and the wavy top layer can be coated on both sides with an electrically conductive material and designed as tempering surfaces.

[0017] Furthermore, in the heating element according to the invention, it is advantageous if the electrically conductive layers of the sublayers are each equipped with conductor tracks that are closely spaced from each other and distributed over the surfaces of the layers, thereby enabling effective heat transfer to the flowing liquid.

[0018] In the heating element, the winding arrangement of the heating conductor in cross-section or transverse to the longitudinal center axis of the cylindrical housing can form a uniform spiral or worm-like arrangement, in which the distances between the superimposed winding layers are largely constant.

[0019] Optionally, the heating element can be equipped with at least one temperature measuring range, which is advantageously located in the area of ​​the flat and / or corrugated sections or sub-layers, thus enabling relatively accurate temperature measurement within the heating element. For example, with at least one conductor circuit, the change in resistance with temperature could be used as a temperature sensor, allowing the variable temperature coefficient of the metal to be utilized. This would provide a temperature sensor integrated into the heating element that does not alter the flow pattern. If this sensor circuit is distributed across the entire heating surface, it can measure an average temperature. If it is placed only in the outflow area, it can measure the resulting water temperature.

[0020] The heating element functions as a type of foil water heater. The corrugated and spirally wound foil heating element comprises heating conductors that can be heated by applying a voltage. The heating conductors can be specially shaped or have varying densities on the heating foil, allowing for local optimization of the heating power density. For example, it can be advantageous to heat the section of the heating coil where the cold water first enters more intensely. Similarly, in cases of non-uniform flow, the area with higher flow can be heated more intensely, while areas with lower flow can be heated less to ensure a uniform heat distribution within the fluid. Often, adjusting the local heating power is simpler than investing significant effort in achieving a uniform flow.

[0021] Another option is to divide the heating elements into multiple heating circuits. This allows the heating output to be easily increased or decreased by switching additional circuits on or off. Furthermore, this method eliminates the need for costly power semiconductor components, whose power adjustment requires pulse-width modulated control.

[0022] The heating element according to the invention makes it possible to heat all types of water-cooled systems used for battery units, in particular for traction batteries in vehicle drives.

[0023] To achieve the aforementioned goal, the invention proposes, in addition to the electric heating element described in various embodiments, a liquid circuit for temperature control of a liquid-cooled battery unit of a drive and energy supply unit of a vehicle drive system. The liquid is circulated in the liquid circuit by means of a pump and can thus be conveyed through the liquid-cooled battery unit.

[0024] In a defined flow section of the liquid circuit, there is at least one electrically operated heating element equipped with flow channels whose channel walls are designed as planar heating conductors to enable heat transfer to a liquid circulating or flowing through the flow channels, which then enters the battery unit and heats it.

[0025] In the liquid circuit according to the invention, the at least one electrical heating element can be designed in particular according to one of the previously described embodiments.

[0026] Furthermore, the liquid circuit according to the invention can advantageously be equipped with a control and / or regulation unit for temperature control, which can supply the electric heating element with an adjustable supply voltage according to the respective heating requirement of the liquid.

[0027] The following exemplary embodiments of the invention and its advantages will be explained in more detail with reference to the accompanying figures. The relative sizes of the individual elements in the figures do not always correspond to the actual relative sizes, as some shapes are simplified and others are enlarged for better illustration. Fig. Figure 1 shows a schematic circuit diagram of a liquid circuit with an electrical heating element arranged therein, which can be used to temperature control a liquid circulating through a battery unit. Fig. Figure 2A shows a schematic and perspective view of the heating element according to Fig. 1, through which liquid can be conveyed. Fig. Figure 2B shows an internal structure of the heating element according to Fig. 2A with a multitude of flow channels through which the liquid to be heated can flow. Fig. Figure 2C shows a layer structure of a heating conductor that can be inserted into the heating element. Fig. 2D shows a front view of the heating conductor with its multitude of flow channels. Fig. Figure 3A shows a first embodiment of a conductor track structure of a planar heating conductor as well as its wound structure located in the heating element. Fig. Figure 3B shows a second embodiment of a conductor track structure of the planar heating conductor as well as its wound structure located in the heating element. Fig. Figure 3C shows a third design variant of a conductor track structure of the planar heating conductor as well as its wound structure located in the heating element. Fig. Figure 4A shows a first variant of a layer structure of the planar heating conductor. Fig. Figure 4B shows a second variant of the layer structure of the planar heating conductor.

[0028] Identical reference numerals are used for identical or equivalently functioning elements of the invention. Furthermore, for the sake of clarity, only those reference numerals necessary for describing the respective figure are shown in the individual figures. The illustrated embodiments merely represent examples of how the device according to the invention may be configured and do not constitute an exhaustive limitation.

[0029] The schematic representation of the Fig. Figure 1 shows a drive and energy supply unit 10 for an electric vehicle drive 12 with at least one electric drive motor 14, the electrical energy supply of which is ensured by a rechargeable battery or accumulator unit 16 with a plurality of battery cells 18. The battery cells 18 together form the battery or accumulator unit 16 and are connected in series in a suitable arrangement to provide a desired output voltage. In addition, several such groups of battery cells 18 are generally connected in parallel to ensure a desired total electrical power. The construction of such a battery or accumulator unit 16 is not shown in detail here, as it can be assumed to be known to those skilled in the art.

[0030] Between the drive motor 14 and the battery or accumulator unit 16 is at least one control unit 20, which not only controls or regulates the delivered drive power according to the driver's current requirements, but also normally ensures the recuperation of electrical energy during braking or coasting. Furthermore, it is essential that the entire energy and charging management system is monitored, controlled, and regulated by this control unit 20. The complex range of functions of such a control unit 20 need not be discussed in detail here, but can also be assumed to be sufficiently familiar to those skilled in the art.

[0031] Since such battery units 16 or accumulator modules, as shown schematically here and used as part of the drive and energy supply unit 10 for the drive motor 14 of the vehicle drive 12, are subject to relatively high loads both during charging and during their intended use as an electrical energy source, and since the battery cells 18 typically used for this purpose develop their electrical properties best and reach their maximum capacity within a limited temperature range, temperature control of the battery cells 18 or the entire battery unit 16 is generally advisable. In addition, considerable heat is generated both during charging, especially during high-power fast charging, and during high power demands from driving, so that temperature control is frequently required throughout operation.

[0032] The one in Fig. A schematically shown drive and energy supply unit 10 comprises a fluid circuit 22 with at least one pump 24 for circulating a fluid within the fluid circuit 22. This fluid, circulated by the pump 24, flows on the one hand through the battery unit 16 and can optionally flow through a heat exchanger 26, which allows for on-demand cooling of the circulating fluid and thus also of the battery unit 16 when the battery cells 18 heat up considerably due to a charging process or high power demands from the drive motor 14 of the vehicle drive 12.

[0033] However, since the temperature range for high performance of the battery cells 18 should not fall significantly below approximately 15 to 20°C, the liquid circuit 22 also contains a controllable and / or adjustable electric heating element 28, which is likewise exposed to the circulating liquid. This electric heating element 28, which receives a controlled supply voltage 30 from the control unit 20, is explained in detail below with regard to its structure and function as part of the drive and energy supply unit 10 and as part of the liquid circuit 22 coupled to it.

[0034] The electric heating element 28 shown here thus serves to quickly and effectively heat the liquid circulating in the liquid circuit 22, thereby forming a defined flow section 32 within the liquid circuit 22 and can thus provide for a thermal exchange with the battery cells 18 of the battery unit 16.

[0035] The perspective views of Fig. 2A and Fig. Figure 2B shows an embodiment of a liquid-flowing electric heating element 28, which is used for the targeted and controllable heating of the liquid circuit 22 (see Figure 2B). Fig. 1) can be used with circulating fluid. The heating element 28 comprises a housing 34 with a cylindrical body 36 and conical outlet funnels 38 at both ends, each opening into line connections 40.

[0036] The two conical outlet funnels 38 can, for example, each have a length in the direction of the longitudinal central axis 42 that corresponds approximately to one quarter of the length of the cylindrical body 36. The cylindrical body 36 can, for example, have a diameter that corresponds to half its length. A suitable cross-section for the two line connections 40, between which the in Fig. The flow section 32 shown, with the electrical heating element 28 arranged therein, can be approximately one quarter or less of the outer diameter of the cylindrical body 36.

[0037] In the interest of low flow resistance, the line connections 40 opening into the housing 34 on both sides can be aligned with each other, preferably in simultaneous alignment with a longitudinal center axis 42 of the housing 34 and its cylindrical body 36, as shown in the Fig. 2A is shown as an example.

[0038] Thus, the liquid circulating in the fluid circuit 22 can enter the housing 34 of the heating element 28 at a first line connection 40 and exit the housing 34 again at the opposite second line connection 40, whereby the exiting liquid can be tempered as required, i.e., heated relative to the inlet side. To achieve this, the liquid flowing through the heating element 28 can be tempered or heated within the cylindrical body section 36 of the housing 34 by means of electrical heating conductors 44 arranged there.

[0039] As a summary of Fig. 2B, Fig. 2C and Fig. As can be illustrated in 2D, the electrical heating element 28 is located inside the housing 34 (see figure). Fig. 2A) the actual electrical heating conductors 44, which form a conductive layer on a surface of a compactly rolled-up planar support 46. The support 46 shown, on which the electrical heating conductors 44 are arranged, is a two-part planar support layer 48 or support film 48, the first sublayer 50 of which is initially aligned flat in order to apply a second sublayer 52 to it, as shown in the Fig. 2C illustrates this.

[0040] Both the flat first sublayer 50, which is visible in the side view of the Fig. Both the lower sublayer 2C and the second sublayer 52, located above it and attached to the first sublayer 50, are each equipped with heating conductors 44, which will be described in more detail below, in order to form the heatable flow channels 54. Since the second sublayer 52 has a corrugated structure with a uniformly meandering surface, it can be placed in line contact with the first sublayer 50 and then bonded to the first sublayer 50, which is also described in the Fig. 2C is clearly recognizable.

[0041] Since the mutually facing surfaces of the two sublayers 50 and 52 of the carrier 46 are each equipped with heating conductors 44, and since the cavities formed between the joined sublayers 50 and 52 each form flow channels 54 which are arranged according to Fig. Since all 2D extend parallel to the longitudinal center axis 42 of the heating element 28, the liquid flowing through the flow channels 54 can be brought to a desired elevated temperature depending on the selected application of electrical energy to the heating conductors 44.

[0042] The Fig. Figure 2D shows that the two-layer carrier 46 is spirally wound or wound around the longitudinal central axis 42 of the heating element 28, so that a large number of flow channels 54 are provided between the radially spaced areas of the planar carrier 46 or the carrier film 48 for the fluid flowing through the heating element 28. Since the meandering, corrugated second sublayer 52, which is applied to the first sublayer 50 of the carrier 46, defines a certain thickness of the carrier 46 thus formed, the following results, for example, in Fig. 2D shown winding structure of the carrier layer 48 wound according to the diameter of the housing 34, wherein the wave structure of the second sublayer 52 as well as the distances of the respective wave troughs or wave crests determine both the opening cross-section of the flow channels 54 and the distance of the successive winding layers in the according to Fig. Specify 48 on a 2D spirally wound carrier film.

[0043] The possible total number of flow channels 54 also results from the number of winding layers of the two-part carrier layer 48, consisting of the two joined sub-layers 50 and 52, that fit into the cylindrical housing 34 and form the carrier 46 with the electrical heating conductors 44 applied to it. As the Fig. As can be seen in the 2D drawing, the interior of the cylindrical housing 34 is equipped with the aforementioned multitude of flow channels 54, through which the fluid to be tempered can flow parallel to the longitudinal central axis 42 of the cylindrical housing 34. An alternative embodiment is explained and illustrated below, in which the flow channels 54 run helically due to a differently structured second sublayer 52, which may be desirable for fluid dynamic reasons.

[0044] Since the wave structure of the second sublayer 52 according to Fig. Since the flow path 2C runs regularly over its entire surface, the resulting flow channels 54 extend with approximately constant cross-sections through the longitudinal direction of the housing 34 of the heating element 28. The desired heat transfer to the fluid flowing through the flow channels 54, which is used to temper the battery cells 18 of the drive and energy supply unit 10 (see Figure 2C) is achieved by means of a flow channel 54 with approximately constant cross-sections. Fig. 1) is used by the electrical heating conductors 44, which are explained in detail below and are formed at least in part of the channel walls.

[0045] Preferably, the planar heating conductors 44 extend over the entire length of the respective flow channels 54 within the housing 34. This necessitates a complete planar coating of the respective carrier layer 48, preferably on the first sub-layer 50 as well as on the corrugated second sub-layer 52 attached to it.

[0046] For the planar heating conductors 44, which are applied as closely spaced conductor tracks 56 with parallel paths and end-end 180° deflections on the respective carrier layers 48, i.e. on the first sublayer 50 as well as on the second sublayer 52, according to Fig. 3A, Fig. 3B or Fig. 3C models have different additional functions. This is illustrated by the Fig. 3A is an embodiment in which a narrow section of the conductor tracks 56, namely the section located on the right in the top view of the support layer 48 shown on the left, is designed as a temperature measuring area 58, which is connected to the Fig. 1 The control and regulation unit 20 shown can supply a corresponding temperature signal, so that temperature control is enabled for the unit 20.

[0047] The conductive traces 56 applied to the carrier film 48, due to their internal resistance, cause the desired heating when an electric current flows through them. Since they cover almost the entire surface of the carrier film 48, it acts as a planar heating element.

[0048] In the right-hand representation of the Fig. In Figure 3A, where the carrier 46 is shown in its unwound state, this temperature measuring range 58 is located in the right section of the carrier 46, i.e., near the downstream outlet funnel 38 of the heating element 28 (see Figure 3A). Fig. 2A), so that the temperature after flowing through the flow channels 54 of the heating element 28 is effectively detected and transmitted as an electrical signal to the control and regulation unit 20 (see Fig. 1) can be made available.

[0049] Furthermore, the Fig. 3B is an embodiment in which a narrow section of the conductor tracks 56, namely the section located on the left in the top view of the carrier layer 48 shown on the left, is designed as a separately controllable sub-area 60, thereby preferably enabling graduated temperature control. This separately controllable sub-area 60 of the conductor tracks 56 can thus be controlled separately from the other areas and, in particular, subjected to different temperatures, so that this sub-area 60 can, for example, be heated more intensively.

[0050] In the right-hand representation of the Fig. Figure 3B, in which the carrier 46 is shown in its unwound state, this separately controllable sub-area 60 is located, according to a preferred embodiment of the heating element 28, in the left section of the carrier 46, i.e., near the upstream outlet funnel 38 of the heating element 28, so that the temperature can initially be increased more strongly after flowing into the flow channels 54 of the heating element 28 and subsequently further increased with moderate heating effect.

[0051] Furthermore, the Fig. 3C represents a further embodiment in which defined longitudinal sections 62 of the carrier layer 46 can be designed as separately controllable subsections of the conductor tracks 56, thereby enabling graduated temperature control, but here for the case of unevenly flowed channels 54, so that the liquid passing through them also heats up unevenly. Such separately controllable longitudinal sections 62, which can, for example, be heated to a higher temperature, allow less flowed channels 54 to be heated more intensely, thus achieving a more uniform temperature of the liquid across the entire cross-section of the heating element 28 within the housing 34.

[0052] However, such graduated temperature control requires a correspondingly spatially resolved temperature measurement, which is achieved by appropriately subdivided temperature measurement ranges 58 (cf. Fig. 3A) can be ensured. The different temperatures in different sub-areas of the flow channels 54 can be roughly as shown in the right-hand image of the Fig. 3C is visualized, showing a top view of the wound carrier 46 with differently measured temperature profiles of the liquid flowing through the channels 54.

[0053] The different areas 58, 60 and 62 of the conductor track structures 56 can optionally be combined with each other, so that different temperature measurement ranges 58 (cf. Fig. 3A) with more temperature-controlled sub-areas 60 along the flow direction (see Fig. 3B) and / or with longitudinal sections 62 of the conductor tracks 56 that can be heated to a greater or lesser degree and thus controlled separately in any way that is appropriate.

[0054] Each one is located in the middle of the Fig. 3A, Fig. 3B and Fig. The arrows located in 3C, which point to the right, are intended to represent the transformation of the initially according to Fig. 2C flat carrier 46, in which the two sublayers 50 and 52 are joined together. The carrier 46 is rolled up in the manner shown, so that it forms the Fig. 2B and Fig. The barrel-shaped contour shown in 2D can be inserted into the interior of the cylindrical housing 34.

[0055] The Fig. 4A and Fig. Figure 4B illustrates two alternative design variants. The front view shows an end face of the two-layer carrier 46 ( Fig. 4A above) recognize that the longitudinal directions of the regularly spaced waves and valleys of the corrugated second sublayer 52, which is connected to the flat lower sublayer 50 and together with it forms the flow channels 54, are perpendicular to the side edges of the still flat support layer 48 ( Fig. 4A below).

[0056] In this embodiment, the winding direction is transverse to this, i.e., transverse to the longitudinal directions of the shafts and carriers of the second sublayer 52, so that in the wound or rolled state of the carrier 46 (cf. Fig. 2B and Fig. 2D) the longitudinal extension directions of all parallel flow channels 54 also parallel to the longitudinal extension direction 42 of the entire heating element 28 (cf. Fig. 2A). The temperature control fluid flowing through the flow channels 54 is therefore not deflected obliquely.

[0057] In contrast, the second version proceeds according to Fig. 4B The longitudinal directions of the regularly spaced waves and troughs of the corrugated second sublayer 52, which is connected to the flat lower sublayer 50 and together with it forms the flow channels 54, are not exactly perpendicular to the side edges of the still flat support layer 48, but form an acute angle of, for example, 10° to about 25° with it (cf. the Fig. 4B below).

[0058] However, in this embodiment as well, the winding direction is transverse to the side edges of the rectangular support 46, so that the same acute angles to the longitudinal directions of the shafts and supports of the second sublayer 52 are maintained. It follows that in the wound or rolled state of the support 46 (cf. Fig. 2B and Fig. 2D) The longitudinal directions of all parallel flow channels 54 also run at an acute angle of approximately 10° to 25° to the longitudinal direction 42 of the entire heating element 28. The temperature control fluid flowing through the flow channels 54 is thus deflected obliquely and thereby acquires a vortex-like swirl.

[0059] Other design variants are conceivable, which differ from the variants according to Fig. 4A and according to Fig. 4B can distinguish, e.g., those with non-straight longitudinal directions of the flow channels 54, but moderately wavy or meandering courses or the like.

[0060] As a result, the invention provides an effective, temperature-controlled surface area of, for example, about a quarter of a square meter, which can be housed within a heating element 28. This heating element 28 can have a housing length of, for example, only about fifteen to twenty centimeters, and a practical housing diameter of less than ten centimeters. Such a heating element 28 can easily be integrated into a liquid circuit 22 for temperature control of a battery unit 16, as described above. Fig. 1 was described using the example of an electric vehicle drive 14.

[0061] The invention has been described with reference to a preferred embodiment. However, it is conceivable to a person skilled in the art that modifications or changes to the invention can be made without departing from the scope of protection of the following claims.

[0062] The evaluation electronics could measure the resistance of a circuit and determine the water temperature using the temperature coefficient of aluminum. The electronics could then heat this circuit, for example, by 5°C and determine the required energy (voltage * current). The faster the water flows through, the more energy is needed to maintain that extra 5°C. This would allow for a very simple implementation of a flow sensor. If this sensor were to detect a cessation of flow, the heating circuits could be switched off to prevent overheating. Reference symbol list 10 Drive and energy supply unit 12 Vehicle drive 14 Drive motor, electric drive motor 16 Battery unit, accumulator unit, battery module, accumulator module 18 battery cells 20 Control unit, regulating unit, control and / or regulating unit 22 Fluid Cycle 24 pump 26 heat exchangers 28 Heating element, electric heating element 30 Supply voltage 32 Flow section 34 cases 36 Body, cylindrical body, body section 38 Muzzle funnels 40 line connection 42 Longitudinal center axis 44 Heating conductor, electric heating conductor 46 carriers 48 Carrier layer, carrier film 50 first sub-shift 52 second sub-layer, corrugated second sub-layer, corrugated top layer 54 Flow channel 56 conductor tracks 58 Temperature measuring range 60 separately controllable sub-areas 62 longitudinal sections, separately controllable longitudinal sections

Claims

[1] Heating element (28) for forming a flow section (32) for a liquid circuit (22) provided for thermal exchange with a drive battery (16), comprising - at least one electrical heating conductor (44) and - a carrier (46) on which the at least one electrical heating conductor (44) is arranged, characterized by that the carrier (46) is a carrier layer or carrier film (48) which is wound spirally around a longitudinal central axis (42) of the heating element (28), wherein a flow channel (54) or a plurality of flow channels (54) for liquid is / are provided between regions of the carrier layer or carrier film (48) which are spaced apart from one another in the radial direction. [2] Heating element (28) according to claim 1, whose particularly cylindrical housing (34) accommodates the electrical heating conductor (44). [3] Heating element (28) according to claim 1 or 2, wherein the electrical heating conductor (44) is provided with a plurality of flow channels (54) through which the liquid to be tempered can flow substantially parallel to the longitudinal central axis (42) of the cylindrical housing (34) or of the heating conductor (44). [4] Heating element (28) according to one of claims 1 to 3, wherein the flow channels (54) each extend with approximately constant cross sections through the longitudinal direction of the heating conductor (44). [5] Heating element (28) according to one of claims 1 to 4, in which at least sections of the channel walls of the flow channels (54) are designed as heatable surfaces which can effect a heat transfer when the liquid flows past from the heating conductor (44) to the liquid. [6] Heating element (28) according to claim 5, wherein the heatable surfaces of the flow channels (54) extend over the entire length of the respective flow channels (54). [7] Heating element (28) according to claim 5 or 6, wherein the heatable surfaces of the flow channels (54) have separately controllable regions over their longitudinal extent, which are separated from one another and which can be subjected to different temperatures. [8] Heating element (28) according to one of claims 1 to 7, which comprises a wound flat heating conductor (44) which is provided with a corrugated cover layer (52) which is applied in regular line contact to a first flat partial layer (50) and forms the regularly spaced flow channels (54) between the two layers (50, 52). [9] Heating element (28) according to claim 8, wherein both the first planar partial layer (50) and the corrugated cover layer (52) are each coated with an electrically conductive coating at least on their facing surfaces and are designed as a tempering surface. [10] Heating element (28) according to claim 8, wherein both the first flat partial layer (50) and the corrugated cover layer (52) are each coated on both sides in an electrically conductive manner and are designed as tempering surfaces. [11] Heating element according to claim 9 or 10, wherein the electrically conductive layers of the sub-layers (50, 52) are each provided with conductor tracks (56) which are closely spaced from one another and distributed over the surfaces of the layers (50, 52). [12] Heating element (28) according to one of claims 1 to 11, which is equipped with at least one temperature measuring region (58) which is located in the region of the flat and / or wavy sections or the partial layers (50, 52). [13] Liquid circuit (22) for controlling the temperature of a liquid-cooled battery unit (16) of a drive and energy supply unit (10) of a vehicle drive (14), wherein the liquid in the liquid circuit (22) can be circulated by means of a pump (24) and conveyed through the liquid-cooled battery unit (16), wherein in a defined flow section (32) of the liquid circuit (22) there is at least one electrically operated heating element (28) which is equipped with flow channels (54) whose channel walls are designed as flat heating conductors (44). [14] Liquid circuit (22) according to claim 13, wherein the at least one electrical heating element (28) is designed according to one of claims 1 to 12. [15] Liquid circuit (22) according to claim 13 or 14, which is equipped with a control and / or regulating unit (20) for temperature control, which can apply a controllable supply voltage (30) to the electrical heating element (28).

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