DE102017206439A1 - Optimized wire for a coil for inductive charging - Google Patents

Abstract

An electrical line (500, 510), in particular a strand, for windings of an electrical coil (203) is described. The electrical line (500, 510) comprises a tubular, deformable carrier (505), wherein the carrier (505) is formed such that by pressure on the carrier (505) reduces a cavity (502) enclosed by the carrier (505) can be. In addition, the electrical line (500, 510) comprises a plurality of individual wires and / or wire packages (302), which are arranged on the outside of the carrier (505), so that the individual wires and / or wire packages (302) in a longitudinal direction of the tubular carrier (302). 505) run helically, wherein the individual wires and / or wire packages (302) are electrically insulated from one another by insulation.

Description

The invention relates to a stranded wire for a coil, in particular for a coil for inductive charging. Furthermore, the invention relates to a method for producing such a strand.

Electric vehicles typically have a battery in which electrical energy can be stored to operate an electric machine of the vehicle. The battery of the vehicle can be charged with electrical energy from a power grid. For this purpose, the battery is coupled to the power grid to transfer the electrical energy from the power grid into the battery of the vehicle. The coupling can be wired (via a charging cable) and / or wireless (based on an inductive coupling between a charging station and the vehicle).

One approach to automatically, wirelessly, inductively charging the battery of the vehicle is to transmit electrical energy to the battery from the floor to the underbody of the vehicle via magnetic induction via the underbody clearance. This is exemplary in 1 shown. In particular shows 1 a vehicle 100 with a storage 103 for electrical energy (eg with a rechargeable battery). The vehicle 100 comprises a so-called secondary coil in the vehicle underbody, wherein the secondary coil is connected to the accumulator 103 for electrical energy via an impedance matching, not shown, and a rectifier 101. The secondary coil is typically part of a so-called "Wireless Power Transfer" (WPT) vehicle unit 102.

The secondary coil of the WPT vehicle unit 102 can be positioned over a primary coil, with the primary coil e.g. attached to the floor of a garage. The primary coil is typically part of a so-called WPT ground unit 111. The primary coil is connected to a power supply 110. The power supply 110 may include a radio-frequency generator that generates alternating current (AC) in the primary coil of the WPT ground unit 111, thereby inducing a magnetic field (particularly, an electromagnetic charging field). The electromagnetic charging field may have a predefined charging field frequency range. The charging field frequency range can be in the range of 80-90 kHz (in particular at 85 kHz).

With sufficient magnetic coupling between the primary coil of the WPT base unit 111 and the secondary coil of the WPT vehicle unit 102 on the underbody clearance 120, a corresponding voltage and thus also a current in the secondary coil is induced by the magnetic field. The induced current in the secondary coil of the WPT vehicle unit 102 is rectified by the rectifier 101 and stored in the memory 103. Thus, electrical energy can be transmitted wirelessly from the power supply 110 to the energy storage 103 of the vehicle 100. The charging process may be controlled in the vehicle 100 by a charging controller 105. The load controller 105 may be configured for this purpose, e.g. wirelessly communicating with the loading unit 110 (e.g., a wallbox) or with the WPT ground unit 111.

The primary coil and / or the secondary coil typically each comprise at least one electrical line forming a plurality of turns of the primary coil or the secondary coil. In this case, because of the relatively high charging field frequency, an electrical line is typically designed as a HF (radio-frequency) strand with a plurality of individual wires in order to reduce the effects of current displacement effects, such as the skin and proximity effect, on the electrical resistance of the electrical line to reduce.

Effectively reducing the effects of differential current displacement effects on electrical resistance typically requires the use of relatively small diameter (e.g., in the range of 0.05 to 0.1 mm) single wires. The production and further processing of such thin individual wires leads to relatively high costs.

The present document addresses the technical problem of providing an electrical lead, in particular an RF lead, for a coil for inductive charging, which allows the use of relatively large diameter leads in order to reduce the cost of a coil for inductive charging ,

The object is solved by the independent claims. Advantageous embodiments are described, inter alia, in the dependent claims. It should be noted that additional features of a claim dependent on an independent claim without the features of the independent claim or only in combination with a subset of the features of the independent claim may form a separate invention independent of the combination of all features of the independent claim, the subject of an independent claim, a divisional application or a subsequent application. This applies equally to technical teachings described in the specification, which is one of the features of independent claims can form independent invention.

According to one aspect, an electrical line, in particular a strand, for windings of an electrical coil is described. The electrical line comprises a tubular, deformable carrier. The carrier may, in an initial state, have a tubular support wall enclosing a cavity. In this case, the carrier may be formed such that reduced by pressure on the carrier of the enclosed by the carrier cavity, in particular eliminated, can be. The carrier may e.g. in the initial state have a circular cross-section.

In addition, the electrical line comprises a plurality of individual wires and / or wire packages, which are arranged on the outside (the support wall) of the carrier. In this case, the outside of the support wall of the carrier corresponds to the side facing away from the cavity side of the support wall. In other words, the outside of the carrier corresponds to the side of the support wall which faces away from the enclosed cavity. The electrical line typically does not include single wires and / or wire packages on the inside of the carrier. In particular, the cavity of the carrier enclosed by the inside of the support wall may contain only a gaseous medium (e.g., air). Thus, it can be ensured that the cavity of the carrier (i.e., the entire space enclosed by the inside of the carrier wall of the carrier) can be eliminated by squeezing.

A wire package may include multiple individual wires. The individual wires of a wire package can be electrically isolated from each other. An electrical line may possibly have only individual wires or possibly only wire packages.

The plurality of individual wires and / or wire packages are preferably arranged on the outside of the carrier such that the individual wires and / or wire packages run helically in the longitudinal direction of the tubular carrier. By such an arrangement of the individual wires and / or wire packages Stromverdrängungseffekte can be reduced. Each individual wire and / or each wire package can thus form a helix that winds around the outside of the support wall. The pitch of the helix may be substantially greater than the diameter of the cross-section of the beam (e.g., by a factor of 3, 5, 10 or more).

Furthermore, the individual wires and / or wire packages are arranged on the outside of the carrier in such a way that the individual wires and / or wire packages are electrically insulated from one another by insulation. The strands and / or wire packs and insulation may completely cover the outside of the carrier. Thus, relatively many individual wires and / or wire packages can be installed in an electrical line. By way of example, the electrical line L can comprise individual wires and / or wire packages, with L> 5 or L> 10 or L> 20.

Thus, an electrical lead, in particular an HF lead, can be provided, which can be flexibly installed in a coil in order to reduce current displacement effects within the coil. In particular, the electrical line can be installed in a compressed state in a coil, resulting in a relatively uniform arrangement of individual wires and / or wire packages within the coil. As a result, current displacement effects (in particular proximity effects) can be reduced, which makes it possible to use inexpensive individual wires and / or wire packages with a relatively large wire diameter. In addition, electrical losses are reduced by reducing current displacement effects. Thus, inexpensive and energy-efficient coils for inductive charging systems can be provided.

The electrical line can form a flat electrical cable in the contracted state. In this case, the carrier may be plastically deformable, so that the carrier remains in the compressed state after compression of the carrier. Thus, flat conductors for a coil can be manufactured efficiently.

The carrier may have on the outside a plurality of partitions, which run helically in the longitudinal direction of the carrier. Adjacent partitions can then each form a channel-shaped chamber for receiving a single wire or a wire package. By providing partitions, a reliable storage of the individual wires or the wire packages can be effected. Furthermore, the insulation between the individual wires and / or wire packages can be formed at least partially by the partitions. The individual wires and / or wire packages may then possibly not be coated with an electrically insulating insulating layer. Thus, the cost of an electrical line for a coil can be further reduced. In particular, it is thus possible to apply a single wire and / or a wire package to the carrier, which do not have their own electrical insulation with respect to another individual wire and / or another wire package.

The partitions may be deformable and / or elastic. In this case, the partitions along the longitudinal direction of the carrier can be parallel (to each a suitable channel for Recording a single wire and / or a wire package to form). Furthermore, the dividing walls can have bulges and / or curves along the longitudinal direction of the carrier, as opposed to a straight course. The individual wires and / or wire packages can then have corresponding bulges and / or curves. Such bumps and / or curves can be used to increase the bendability of the electrical line.

In a corresponding manner, the carrier can be elastic, in particular the carrier wall can be elastic. Furthermore, the circumference or cross section of the carrier may vary along the longitudinal direction of the carrier. In particular, a diameter of the cross section of the carrier may vary along the longitudinal direction of the carrier. In other words, for a point of the cross section of the carrier along the longitudinal direction of the carrier, the carrier may have bulges and / or curves other than a straight course. As a result, the individual wires and / or wire packages may have bulges and / or curves in the radial direction (with respect to a longitudinal axis of the carrier). Such bumps and / or curves can be used to increase the bendability of the electrical line.

The electrical line can have a tubular jacket which encloses the individual wires and / or wire packages. In this case, the jacket can be electrically insulating. Through a jacket which encloses the individual wires and / or wire packages, the electrical line can be stabilized. Furthermore, it is possible to provide the insulation between different turns of a coil.

The electrical line may be designed for a coil which is operated with an alternating current, wherein the alternating current in particular has a frequency from the frequency range from 80 kHz to 90 kHz. The individual wires and / or wire packages can each have a diameter which is between a single and a double penetration depth of the skin effect for the alternating current with the respective frequency. Due to the uniform arrangement of the individual wires and / or wire packages, proximity effects can be substantially reduced so that current displacement is primarily caused by the skin effect. As a result, a dimensioning of the individual wires and / or wire packages can be done solely on the basis of the skin effect. It is therefore possible to use single wires and / or wire packages with an increased diameter.

In another aspect, an electrical coil is described. In particular, the coil may be used for inductively charging a memory for storing electrical energy for driving an electric vehicle, e.g. a passenger car, a lorry or a motorbike. Furthermore, the coil can be designed for the transmission of electrical energy with a charging field frequency in the range of 80kHz to 90kHz. The electrical coil comprises N turns of the electrical lead described in this document, with N> 1 (typically N> 2, 5, 7 or 10). The electrical line may be at least partially formed as a flat cable, i. the electrical line can be at least partially in the compressed state. The compression can take place during the installation of the electrical line in the coil. For example, the carrier of the electrical line can be elastically deformable. The electrical lead can then be held in the compressed state by a coil carrier of the coil. Thus, a flexible shoring of the electrical flat cable can be made possible in a coil.

The electrical lead may be wound within the coil about a central axis of the coil. The coil may have a first region in which the electrical line is bent relatively strong about the central axis. Furthermore, the coil may have a second region in which the electrical lead is bent relatively little (e.g., in which the electrical lead is substantially rectilinear). The carrier of the electric wire may be compressed in the first region in the radial direction with respect to the central axis (so that a relatively small bending radius is made possible). On the other hand, the carrier of the electric wire in the second area may be compressed in the direction of the central axis (thus allowing a coil having the smallest possible space). The electrical line described in this document can thus be adapted in a flexible manner to different coil requirements.

In another aspect, a coil unit for an inductive charging system for charging an electrical energy storage of a vehicle (e.g., a WPT ground unit or a WPT vehicle unit) is described. The coil unit comprises an electrical coil described in this document. In addition, the coil unit may comprise a coil support and a coil cover, which form at least one chamber for receiving the N turns of the electric wire of the electric coil.

According to a further aspect, a method for producing a flat electrical cable is described. The method comprises applying a plurality of individual wires and / or wire packages to a tubular, deformable Carrier. In this case, the carrier is designed such that reduced by pressure on the carrier enclosed by the carrier cavity, in particular substantially eliminated, can be. In particular, it can be caused by pressure on the carrier that opposite regions of the inside of the support wall of the carrier lie directly on each other.

The individual wires and / or wire packages are applied to the outside of the carrier in such a way that the individual wires and / or wire packages run helically in a longitudinal direction of the tubular carrier and that the individual wires and / or wire packages are electrically insulated from one another by insulation. In addition, the method includes compressing the carrier to provide a flat electrical cable having a plurality of electrically insulated individual wires and / or wire packages. In this case, the carrier can be compressed such that half of the inside of the support wall rests directly on the other half of the inside of the support wall.

In another aspect, a vehicle (e.g., a passenger car, a truck, or a motorcycle) is described that includes a WPT vehicle unit having the electrical coil described in that document.

According to a further aspect, a charging station for charging a vehicle is described, which comprises a WPT ground unit with the electric coil described in this document.

It should be understood that the methods, devices and systems described herein may be used alone as well as in combination with other methods, devices and systems described in this document. Furthermore, any aspects of the methods, apparatus, and systems described herein may be combined in a variety of ways. In particular, the features of the claims can be combined in a variety of ways.

• 1 beispielhafte Komponenten eines induktiven Ladesystems;
• 2a und 2b einen beispielhaften Aufbau einer Spulenanordnung;
• 3a, 3b und 3c einen beispielhaften Aufbau einer Spule und einer HF-Litze;
• Fig. 4a und 4b beispielhafte Verläufe der magnetischen Flussdichte entlang der Windungen einer Spule;
• 5a, 5b und 5c eine beispielhafte elektrische Leitung mit einem Hohlträger;
• 5d ein beispielhafter Verlauf eines Einzeldrahts in einer elektrischen Leitung;
• 5e eine beispielhafte Anordnung einer elektrischen Flachleitung in einer Spule;
• 6 eine beispielhafte Vorrichtung zur Fertigung einer Flachleitung;
• Fig. 7a, 7b und 7c beispielhafte Ausrichtungen einer Flachleitung in einer Spule; und
• 8 ein Ablaufdiagramm eines beispielhaften Verfahrens zur Herstellung einer Flachleitung.

Furthermore, the invention will be described in more detail with reference to exemplary embodiments. Show

• 1 exemplary components of an inductive charging system;
• 2a and 2 B an exemplary structure of a coil assembly;
• 3a . 3b and 3c an exemplary structure of a coil and an RF strand;
• FIGS. 4a and 4b show exemplary courses of the magnetic flux density along the turns of a coil;
• 5a . 5b and 5c an exemplary electrical line with a hollow beam;
• 5d an exemplary course of a single wire in an electrical line;
• 5e an exemplary arrangement of a flat electrical cable in a coil;
• 6 an exemplary apparatus for manufacturing a flat cable;
• Figures 7a, 7b and 7c show exemplary orientations of a flat cable in a coil; and
• 8th a flowchart of an exemplary method for producing a flat cable.

As stated above, the present document is concerned with the provision of a cost and energy efficient inductive charging coil.

2a and 2 B show the exemplary construction of a coil assembly, eg for a WPT ground unit 111 and / or for a WPT vehicle unit 102 , The coil arrangement typically has a ferrite, eg as part of a coil carrier 201 , on, in which the actual coil 203 can be admitted. The sink 203 has a plurality of turns of an insulated electrical line 204 on. The coil assembly may further include mechanical protection or coil cover 202 made of magnetically neutral material to the coil 203 to protect against mechanical effects. 2a shows an exemplary coil assembly in a side view and 2 B shows an exemplary coil assembly in a plan view.

Inductive charging of vehicles 100 relatively high charging field frequencies in the range of about 81 to 90kHz are used. Due to the skin effect and / or the proximity effect, the relatively high charging field frequencies result in an increase of the electrical resistance in a coil 203 can come. This is especially the case when the diameter of the coil 203 used line 204 is large compared to the skin depth or the depth of penetration of the skin effect. The skin depth decreases with increasing charging field frequency of the alternating current in a line 204 the coil 203 , Consequently, to build a coil 203 typically RF (radio frequency) strands 204 used with single wires, wherein the individual wires have a relatively small diameter (eg in the range of 0.07mm). Thus, the resistance-increasing effects of current-enhancement effects, such as the skin effect and / or the proximity effect, can be limited. The cost of making an HF strand 204 However, this typically increases as the diameter of the individual wires decreases.

The 3a . 3b and 3c show an exemplary construction of a coil 300 using an electrical line, in particular an HF strand 301 , A large number of individually insulated individual wires 302 is in an HF strand 301 summarized and with an insulation or with an insulating jacket 303 surrounded (see 3c ). The single wires 302 can be inside the RF strand 301 twisted to reduce the effects of the skin effect and / or the proximity effect. The actual turns or windings of the coil 300 be through the HF wire 301 created. 3a shows in a plan view of the coil 300 like the HF cable 301 in the winding direction 305 around an interior 321 the coil 300 is wound around the coil 300 manufacture. In this case, a central axis of the coil runs 300 perpendicular to the interior 321 , 3b shows an exemplary cross section AA 'through the coil 300 , In particular shows 3b a multitude of turns of the HF strand 301 (total N = 12 turns of the same RF strand 301 with the windings arranged in two layers).

The HF strand 301 is typically made of expensive to produce and therefore expensive, insulated individual wires 302 produced. How out 3b can be seen, is the copper fill factor of a coil 300 when using an HF cable 301 typically relatively small, since both the isolated individual wires 302 must be twisted and thereby create voids, and there the different turns of a round RF strand 301 also have voids to each other. Furthermore, the selection of HF strands 301 typically limited because both the overall diameter of the RF strand 301 (in terms of current carrying capacity of the coil 300 ) as well as the diameter of the individual stranded wires 301 (in terms of the skin effect) must meet appropriate requirements. In addition, the design of the total winding diameter when using an HF strand 301 given narrow limits.

4a shows a cross section of a plurality of turns of an electrical line 301 , where the line 301 a plurality of individual wires 302 having. Further shows 4a the fine course 401 the magnetic flux density along the cross section through the individual turns. Also illustrated 4a the coarse course 402 the magnetic flux density along the cross section, which is caused by the entirety of the turns. From the fine course 401 It can be seen that relatively high magnetic flux densities in the edge regions of the individual lines 301 arise. The current flow in the individual turns of the line 301 is thus limited to the edge regions of the individual turns, resulting in an effective increase in the electrical resistance of the electrical line 301 leads. The skin effect causes a displacement of the current to the edge regions of a single wire 302 , Furthermore, the proximity effect causes current displacement due to the interference of adjacent turns of the line 301 and / or adjacent individual wires 302 ,

4b illustrates that through an optimized arrangement of the turns of a pipe 301 and / or the individual wires 302 the fine course 401 the magnetic flux density can be made uniform, so that a homogenization of the current flow through a line 301 and thus result in a reduction of the electrical resistance. In particular, it is found that by a relatively flat and uniform arrangement of the individual wires 302 along the different turns of a pipe 301 a relatively uniform fine course 401 the magnetic flux density results.

5a shows a cross section of an exemplary electrical line 500 , in particular an exemplary HF strand, as an intermediate product for producing a flat electrical cable 510 (in 5c shown). The electrical line 500 includes a carrier 505 , In particular a tubular and / or tubular support 505 with a circular cross section, which is used to a plurality of individual wires 302 to wear. The carrier 505 can have a variety of partitions 501 include that on the carrier 505 are arranged to different compartments or chambers 503 for receiving different individual wires 302 provide. The partitions 501 If necessary, they can be used to insulate the different individual wires 302 be used, allowing for a different isolation of the individual wires 302 can be waived. Furthermore, also the carrier 505 consist of an electrically insulating material. In addition, the electrical line includes 500 typically an electrically insulating jacket 504 that is the multiplicity of individual wires 302 surrounds.

5b shows the electrical line 500 out 5a in a side view (along the longitudinal direction or the longitudinal axis of the electrical line 500 ). In particular shows 5b the course of the individual wires 302 along the line 500 , The single wires 302 can be thread-like or helical along the electrical line 500 be twisted, so that the location of the individual wires 302 within the cross section of the electrical line 500 constantly changing. This can reduce the effects of current crowding effects.

The carrier 505 the electric wire 500 has a cavity 502 on. Furthermore, the carrier 505 preferably made of a deformable material. The electrical line 500 can then be compressed, leaving the cavity 502 passing through the support wall of the wearer 505 is surrounded, disappears and so that the in 5c illustrated flat cable 510 with a plurality of individual wires 302 forms. This flat cable 510 can then be used to make a coil 203 build. In particular, by several turns of the flat cable 510 a coil 203 be formed. 5e shows the cross section of a coil 203 with a total of eight turns of the flat cable 510 , How out 5e can be seen, results in a relatively uniform arrangement of the individual wires 302 within the cross section of the coil 203 , Consequently, through the flat cable 510 Current displacement effects within a coil 203 be reduced.

To build a coil 203 must the flat cable 510 be bent at least in places (such as in 2 B shown). It must be ensured that the individual wires 302 not be damaged by a too small bending radius and / or by too high a voltage. In particular, at the in 5c illustrated flat cable 510 for bends about a vertically extending bending axis relatively high elongations or compressions, leading to damage to the individual wires 302 could lead. The partitions 501 can therefore be elastic and have a curved course (as in 5d ). In particular, the partitions 501 Buckling in the tangential and / or radial direction (with respect to the carrier 505 ) exhibit. The single wires 302 can then swing in each case a compartment 503 between two curved partitions 501 be recorded. Thus, the expansion forces or compression forces on the individual wires 302 at a bend of the flat cable 510 be reduced.

6 shows an exemplary device 600 for the production of a flat cable 510 , The single wires 302 can through a threading unit 601 into the individual chambers or compartments 503 of the hollow carrier 505 be inserted. The single wires 302 can each be unwound from a roll (not shown). The roles of individual wires 302 can do this at a certain rotational speed around the hollow carrier 505 rotate while the wearer 505 at a propelling speed through the threading unit 601 to be led. Thus, a thread-like or a helical arrangement of the individual wires 302 on the carrier 505 be effected. The pitch or the pitch of the helical arrangement depends on the propulsion speed of the carrier 505 relative to the rotational speed of the individual wires 302 from. Typically, the partitions 501 of the carrier 505 already a helical arrangement on. The propulsion speed and the rotational speed are then on the helical arrangement of the partitions 501 Voted.

In the threading unit 601 or in a subsequent unit (not shown), the jacket 504 the electric wire 500 be applied. The electrical line 500 can then by pressing rollers 602 . 603 be compressed to the flat cable 510 to provide that then on a roll 604 can be rolled up.

7a shows an exemplary coil 203 with a plurality of turns of a flat cable 510 , As in 5c shown, the flat line 510 a certain width and a certain height, wherein the width is greater than the height. Possibly. can the flat cable 510 only when installing in a coil 203 from the electrical line 500 in the original state (ie in the uncompressed state) are formed. The flat cable 510 can then be at different points of the coil 203 be aligned differently. In particular, at the bends of the coil 203 , eg at the cross section AA ' (please refer 7a ), the flat cable 510 so out of the line 500 be formed, that the flat cable 510 for the bend stands on the narrow edge, which is the height 701 having. The cross section AA ' the coil 203 is in 7b shown. The transformation of the line 500 can by a corresponding cavity or chamber in the bobbin 201 and / or in the bobbin cover 202 be effected.

On the other hand, at locations where no bending takes place (see, for example, the cross section BB 'in FIG 7a ), the flat cable 510 be compressed so that the flat cable 510 lying on the wide edge, which is the width 702 has (as in 7c shown). The squeezing of the pipe 500 can eg by the coil cover 202 respectively. By such an arrangement, the height of the coil 203 be reduced.

8th shows a flowchart of an exemplary method 800 for producing a flat electrical cable 510 for a coil 203 , The procedure 800 includes the application 801 of several individual wires and / or wire packages 302 on a tubular, deformable carrier 505 , A wire package may comprise a plurality of individual wires, which are combined to form a package. The individual wires may possibly be electrically isolated from each other. The statements in this document with respect to individual wires are similarly applicable to wire packages.

The carrier 505 is formed such that by pressure on the carrier 505 one from the carrier 505 enclosed cavity 502 reduced, in particular substantially eliminated, can be. For example, the carrier 505 a support wall having a hollow cross-section 502 having. The hollow cross section 502 is preferably circular. By compressing the support wall opposite areas of the support wall can be compressed, so that the cavity 502 reduced or completely eliminated. The carrier 505 then typically has a flat shape, with two opposite areas of the support wall are directly on top of each other.

The individual wires and / or wire packages 302 can be so on the outside of the carrier 505 be applied to the individual wires and / or wire packages 302 in a longitudinal direction of the tubular carrier 505 run helically. In this case, the helix typically has a relatively high pitch or pitch. For example, the pitch of the through a single wire and / or by a wire package 302 formed helix by a factor 5 . 10 . 20 or more than the diameter of the electric wire 500 . 510 ,

In addition, the individual wires and / or wire packages 302 such on the outside of the carrier 505 be applied to the individual wires and / or wire packages 302 are electrically isolated by insulation from or against each other. The insulation can eg by partitions 501 of the carrier 505 and / or by an insulating sheath of the individual wires and / or wire packages 302 respectively.

The procedure 800 further comprises squeezing 802 of the carrier 505 to a flat electrical cable 510 with several electrically insulated individual wires and / or wire packages 302 provide. The squeezing 802 For example, directly in the production of the flat cable 510 respectively. In this case, the carrier is 505 preferably plastically deformable, so that the flat cable 510 the flattened shape at which the wearer 505 typically no cavity 502 more encloses, maintains.

Alternatively, the compression can 802 when installing the electrical line 500 . 510 in a coil 203 respectively. For example, the compression of the line 500 . 510 by pressing it into a prefabricated channel-shaped chamber of a bobbin carrier 201 respectively. In this case, it may be advantageous to have an elastically deformable carrier 505 to use, if necessary, corrections in the deformation of the electrical line 500 . 510 to carry out.

Thus, in this document, a strand construction is described which includes an elastic and hollow inner support 505 includes. The carrier 505 has spacers or partitions on the outside 501 on. To the carrier 505 individual stranded wires (ie individual wires) or stranded packages (ie individual wire packages) 302 are wound in a twisted or helical fashion. The carrier 500 Can be squeezed to a flat cable 510 with an improved distribution of individual wires 392 in the changing room of a coil 203 to reach. The administration 500 . 510 can with a coat 504 be surrounded (eg by extruding a plastic or by wrapping with insulating film) to effect additional protection and / or additional electrical insulation.

The electrical line 500 . 510 has different parameters, such as the thickness of the support wall of the carrier 505 , the thickness of the partitions 501 and / or the diameters of the individual wires 302 , These parameters can be adjusted to the flat cable 510 , ie the HF strand, to the respective requirements of an application (eg current carrying capacity, coil geometry, geometric requirements, etc.).

By an elastic design of the hollow support 505 and / or the spacer elements 501 can be excess lengths of the stranded wires or stranded packages 302 be provided, together with the elasticity of the wearer 505 and any existing sheathing 504 allow relatively small bending radii, even if the flat cable 510 a relatively large ladder width 702 has in the bending direction.

The individual stranded wires or stranded packages 302 can about the carrier 505 and the spacers 501 be insulated electrically to each other, so that, if necessary, no paint insulation of the individual strands or Litzenpakete 302 is required.

Compressing the RF strand 500 may possibly only during or after the winding process to produce a coil 203 respectively. Thus, the strand cross section the specific circumstances along the winding course of the coil 203 be adjusted.

The flat cable described in this document 510 allows an improved distribution of the individual stranded wires or strand packages 302 over the winding cross-section of a coil 203 , As a result, reduced magnetic flux densities along the winding cross-section result and thus reduced skin and proximity effects. Therefore, thicker single wires can 302 for an HF cable 510 be used. For example, individual wires 302 be used with a diameter that is close to twice the penetration depth of the skin effect at the respective charging field frequency (eg with a diameter of more than 0.2mm).

By a suitable construction of an elastic and / or deformable carrier 505 and by an adapted winding method (eg, by applying a bias voltage), a flat cable 510 are produced due to elasticity and overlength of the individual wires 302 allows a relatively small bending radius. In particular, a relatively small ratio of bending radius and cable diameter can be made possible in the bending direction.

By using non-insulated strands 302 may be the cost of an HF strand 510 be further reduced. The transformation of a hollow pipe 500 in a flat cable 510 allows the cross section of the flat cable 510 flexible to the requirements along the circumference of a coil 203 adapt.

The procedure described in this document 800 allows a flat stranded wire 510 without causing substantial stresses in the jacket 504 and / or occur in the strand structure. The scope of the pipe 500 . 510 remains when squeezing the hollow wire 500 constant. On the other hand, the compression of the cross-sectional area of the conduit 510 reduced because of the cavity 520 is reduced or eliminated. Thus, a flat cable 510 with a relatively large ratio between width 702 and height 701 to be provided.

The present invention is not limited to the embodiments shown. In particular, it should be noted that the description and figures are intended to illustrate only the principle of the proposed methods, apparatus and systems.

Claims (15)

Electrical lead (500, 510) for windings of an electrical coil (203), the electrical lead (500, 510) comprising - a tubular, deformable support (505); wherein the carrier (505) is formed such that by pressure on the carrier (505) a cavity (502) enclosed by the carrier (505) can be reduced, in particular substantially eliminated; and a plurality of individual wires and / or wire packages (302) arranged on an outer side of the carrier (505) such that the individual wires and / or wire packages (302) extend helically in a longitudinal direction of the tubular carrier (505); wherein the individual wires and / or wire packages (302) are electrically insulated from each other by insulation. Electric line (500, 510) according to Claim 1 wherein the electrical lead (500, 510) in a contracted state forms a flat electrical lead (510). Electric line (500, 510) according to Claim 2 wherein the carrier (505) is plastically deformable such that the carrier (505) remains in the compressed state. Electric line (500, 510) according to one of the preceding claims, wherein the carrier (505) in an original state has a hollow cross section, in particular a circular cross section. An electrical lead (500, 510) according to any one of the preceding claims, wherein the individual wires and / or wire packages (302) and the insulation substantially completely cover the outside of the support (505). Electric cable (500, 510) according to one of the preceding claims, wherein - The support (505) on the outside a plurality of partitions (501) which extend helically in the longitudinal direction of the carrier (505); and - Between adjacent partitions (501) each have a channel-shaped chamber (503) for receiving a single wire or wire package (302) is formed. Electric line (500, 510) according to Claim 6 in which - the insulation between the individual wires and / or wire packages (302) is at least partially formed by the partitions (501); and / or - the individual wires and / or wire packages (302) are not covered with an electrically insulating insulating layer. Electric line (500, 510) according to one of Claims 6 to 7 in which - the partitions (501) are deformable and / or elastic; the dividing walls (501) run parallel along the longitudinal direction of the carrier (505); and - the partitions (501) along the longitudinal direction of the support (505) have, unlike a straight line curve bulges and / or curves. Electric cable (500, 510) according to one of the preceding claims, wherein - The carrier (505) is elastic; and a circumference of the carrier (505) varies along the longitudinal direction of the carrier (505); and or - The support (505) for a point of a cross section of the support (505) along the longitudinal direction of the support (505) deviating from a straight line curves bulges and / or curves. Electric line (500, 510) according to one of the preceding claims, wherein the electrical lead (500, 510) has a tubular sheath (504) surrounding the individual wires and / or wire bundles (302); and - the sheath (504) is in particular electrically insulating. Electric cable (500, 510) according to one of the preceding claims, wherein - The electrical line (500, 510) L individual wires and / or wire packages (302), with L> 5 or L> 10, comprises; and or - The electrical line (500, 510) is designed for a coil (203) which is operated with an alternating current, which in particular has a frequency in the frequency range from 80 kHz to 90 kHz; and or - The individual wires and / or wire packages (302) each have a diameter which is between a single and a double penetration depth of the skin effect for the alternating current. An electrical coil (203), wherein the electrical coil (203) comprises N turns of an electrical lead (500, 510) according to any one of the preceding claims, with N> 1. Electric coil (203) according to Claim 12 wherein: - the electrical lead (500, 510) is wound around a central axis of the coil (203); - The coil (203) has a first region in which the electrical line (500, 510) is bent relatively strong about the central axis, and a second region in which the electrical line (500, 510) is bent relatively little; - The carrier (505) of the electrical line (500, 510) is compressed in the first region in the radial direction with respect to the central axis; and - the carrier (505) of the electrical line (500, 510) is compressed in the second region in the direction of the central axis. Coil unit (102, 111) for an inductive charging system for charging an electrical energy accumulator (103) of a vehicle (100), wherein the coil unit (102, 111) comprises, - an electrical coil (203) according to one of Claims 12 to 13 ; and a coil support (201) and a coil cover (202) forming at least one chamber for receiving the N turns of the electrical lead (500, 510) of the electrical coil (203). Method (800) for producing a flat electrical cable (510), the method comprising (800) - applying (801) a plurality of individual wires and / or wire packages (302) to a tubular, deformable support (505); wherein the carrier (505) is formed such that by pressure on the carrier (505) a cavity (502) enclosed by the carrier (505) can be reduced, in particular substantially eliminated; wherein the individual wires and / or wire packages (302) are applied to an outside of the carrier (505) such that the individual wires and / or wire packages (302) are helical in a longitudinal direction of the tubular carrier (505) and the individual wires and / or Wire packages (302) are electrically insulated from each other by insulation; and Compressing (802) the carrier (505) to provide a flat electrical lead (510) having a plurality of electrically isolated discrete wires and / or wire packages (302).

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