DE102017217990A1 - Device for guiding magnetic field lines of a coil system and method for manufacturing - Google Patents

Device for guiding magnetic field lines of a coil system and method for manufacturing

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Publication number
DE102017217990A1
DE102017217990A1 DE102017217990.2A DE102017217990A DE102017217990A1 DE 102017217990 A1 DE102017217990 A1 DE 102017217990A1 DE 102017217990 A DE102017217990 A DE 102017217990A DE 102017217990 A1 DE102017217990 A1 DE 102017217990A1
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DE
Germany
Prior art keywords
powder particles
device
characterized
field
element
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
DE102017217990.2A
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German (de)
Inventor
Detlef Helm
Josef Krammer
Tobias Müller
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Bayerische Motoren Werke AG
Original Assignee
Bayerische Motoren Werke AG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Bayerische Motoren Werke AG filed Critical Bayerische Motoren Werke AG
Priority to DE102017217990.2A priority Critical patent/DE102017217990A1/en
Publication of DE102017217990A1 publication Critical patent/DE102017217990A1/en
Pending legal-status Critical Current

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    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01FMAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F38/00Adaptations of transformers or inductances for specific applications or functions
    • H01F38/14Inductive couplings
    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01FMAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00Details of transformers or inductances, in general
    • H01F27/24Magnetic cores
    • H01F27/255Magnetic cores made from particles
    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01FMAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00Details of transformers or inductances, in general
    • H01F27/34Special means for preventing or reducing unwanted electric or magnetic effects, e.g. no-load losses, reactive currents, harmonics, oscillations, leakage fields
    • H01F27/36Electric or magnetic shields or screens
    • H01F27/365Magnetic shields or screens
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02JCIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J50/00Circuit arrangements or systems for wireless supply or distribution of electric power
    • H02J50/10Circuit arrangements or systems for wireless supply or distribution of electric power using inductive coupling
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02JCIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J50/00Circuit arrangements or systems for wireless supply or distribution of electric power
    • H02J50/70Circuit arrangements or systems for wireless supply or distribution of electric power involving the reduction of electric, magnetic or electromagnetic leakage fields
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02JCIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/02Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries for charging batteries from ac mains by converters
    • H02J7/022Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries for charging batteries from ac mains by converters characterised by the type of converter
    • H02J7/025Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries for charging batteries from ac mains by converters characterised by the type of converter using non-contact coupling, e.g. inductive, capacitive
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B60VEHICLES IN GENERAL
    • B60LPROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L53/00Methods of charging batteries, specially adapted for electric vehicles; Charging stations or on-board charging equipment therefor; Exchange of energy storage elements in electric vehicles
    • B60L53/10Methods of charging batteries, specially adapted for electric vehicles; Charging stations or on-board charging equipment therefor; Exchange of energy storage elements in electric vehicles characterised by the energy transfer between the charging station and the vehicle
    • B60L53/12Inductive energy transfer
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02JCIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J2310/00The network for supplying or distributing electric power characterised by its spatial reach or by the load
    • H02J2310/40The network being an on-board power network, i.e. within a vehicle
    • H02J2310/48The network being an on-board power network, i.e. within a vehicle for electric vehicles [EV] or hybrid vehicles [HEV]

Abstract

The invention relates to a device (2) for guiding magnetic field lines (F) of a coil system designed for charging a motor vehicle driven by a motor vehicle having a secondary coil (16) arranged in the motor vehicle, a field-guiding element (4) being provided for guiding the field lines (F). The field guiding element (4) has powder particles (8) made of a ferromagnetic material which are distributed in or on a support structure (6) which consists at least partially of plastic. It also discloses a method for producing such a device (2).

Description

  • The invention relates to a device for guiding magnetic field lines of a coil system having the features of the preamble of claim 1. The invention further relates to a method for producing such a device having the features of the preamble of claim 18.
  • Such a device and methods are known from DE 10 2013 226 830 A1 refer to.
  • For charging a battery of an electric motor driven motor vehicle today, in addition to charging by means of a charging cable and a wireless charging by electromagnetic induction is possible. Under electric motor driven motor vehicle is generally understood a (passenger) cars, which has an electric motor as a drive either in the form of a hybrid drive (electric motor and engine), or in the form of a pure electric motor drive (electric motor).
  • In inductive charging, an alternating electromagnetic field is generated by a primary coil. The primary coil is arranged, for example, in the bottom of a parking space and the motor vehicle to be charged is positioned above the primary coil. The alternating field induces a voltage in a secondary coil arranged on the motor vehicle to be charged, which voltage is simultaneously used to charge the battery of the motor vehicle. For example, the secondary coil is arranged on an underbody of the motor vehicle. In hybrid vehicles, for example, below the engine.
  • In the DE 10 2013 226 830 A1 an arrangement of at least one charging coil is described, which is arranged covered by means of a cover on an underbody of a motor vehicle.
  • Usually, such cover elements are used to protect the charging coils, in particular arranged on the motor vehicle secondary coil from damage. Such damage is, for example, rockfalls and / or Spritzwasserbeaufschlagung, which have either a negative effect on the electrical behavior of the secondary coil and thus on the efficiency of the charging process and / or mechanically damage the secondary coil and thus lead to failure of this.
  • In order to optimize a profile of the field lines of the electromagnetic field with regard to increasing the efficiency of the charging process, ferromagnetic elements, preferably solid ferrite cores, are usually arranged in a vicinity of the secondary coil, in particular in the cover element of the secondary coil. The ferromagnetic elements also cause a field course optimization, so that the charging process is positively influenced.
  • Proceeding from this, the object of the invention is to provide a device and a method by means of which an improved guidance of the magnetic field lines is achieved.
  • The object is achieved by a device having the features of claim 1 and by a method having the features of claim 17.
  • Advantageous embodiments, developments and variants are the subject of the dependent claims. The advantages and preferred embodiments listed with regard to the device are to be transferred analogously to the method and vice versa.
  • The device serves to guide magnetic field lines of a coil system designed to charge a motor vehicle driven by an electric motor (in short: a motor vehicle). The coil system has at least one secondary coil arranged in the motor vehicle. Preferably, the secondary coil is arranged on an underbody, usually in a front region of the underbody of the motor vehicle. To guide the field lines, a field guide element is provided, which is arranged together with the secondary coil, for example on the underbody of the motor vehicle.
  • The field guide element comprises powder particles of a ferromagnetic material, preferably of a ferrimagnetic material. The powder is in particular ferrite powder. Ferrites are generally electrically poor or non-conductive ferrimagnetic ceramic materials of metal oxides, preferably of iron oxide, for example hematite (Fe 2 O 3 ). Due to their poor electrical conductivity, they have almost no eddy current losses. In the present case, powder particles are understood as meaning particles having a maximum mean diameter of 200 μm. Such materials (also called ferrites) have in comparison to other materials on a high magnetic conductivity (also called permeability). The powder particles preferably have a magnetic permeability μ r with a value >> 1, for example a value in the range from 200 to 500. Because of the high permeability magnetic field lines are bundled and guided. This makes it possible to shield desired areas of a motor vehicle from the magnetic field lines by an advantageous arrangement of the powder particles.
  • The powder particles are distributed in or on a carrier structure. The support structure consists at least partially of a plastic, preferably a reinforced plastic. In particular, the support structure is formed from such a plastic.
  • Due to the plastic content, the field guide element as a whole has a permeability with a value in the range of 5 to 15.
  • In an arrangement of ferrite elements, as for example from the already mentioned DE 10 2013 226 830 A1 can be seen, often considered in a vertical direction to the vehicle interior upper portion of the secondary coil is not explicitly shielded by means of ferrite elements. Usually, such an upper region has a protective element, for example made of aluminum. Aluminum has proven to be extremely suitable for shielding field lines of an electromagnetic field. However, an electromagnetic field impinging on the protective element generates eddy currents within the protective element which lead to undesired electrical losses. Even with an arrangement of massive ferrite cores for shielding already described above, magnetic field lines can locally occur in adjacent components, for example in the protective element, on columns between the ferrite elements and generate eddy currents.
  • Due to the properties mentioned, the field-guiding element is advantageous in order, for example, to guide the magnetic field lines occurring in a coil system already described and / or to protect the area of the motor vehicle to be kept clear of the field lines against the field lines and at least to reduce eddy currents. Under the area to be kept free in the present case, for example, a passenger compartment of the motor vehicle is understood. As a result, for example, located in the passenger compartment devices such. a mobile phone of a passenger, not disturbed by the magnetic field lines. Furthermore, the charging process of the motor vehicle is optimized due to the guidance of the field lines, since the efficiency of the coil system is improved.
  • At the same time, the use of powder particles enables more accurate field line guidance. In other words, the powder particles and thus the field guide element have a better "configurability" in comparison to the example already mentioned massive ferrite cores. In this way, an individual arrangement and configuration of the field guiding element and in particular of the powder particles within or on the carrier structure of the field guiding element with respect to a preconditioning, the permeability, the shape and / or the thickness is achieved. Thus, an individual "design" of the field guide element with respect to the secondary coil and / or design-related factors is made possible. In the present case, design-related factors are understood to mean, for example, a surface available on the underbody and / or a predetermined shape of the field-guiding element for the arrangement of the field-guiding element, as well as the electrotechnical requirements and properties of the secondary coil, for example the flowing electrical currents.
  • By the use of powder particles and their embedding in the support structure, a higher resistance to breakage of the field guide element is also achieved than, for example, in a molded into a compact and sintered solid. This refinement is advantageous in particular with regard to vibrations and / or shocks occurring during driving operation of the motor vehicle.
  • The powder particles preferably have an average particle size of not more than 200 .mu.m, preferably of not more than 100 .mu.m and more preferably of not more than 50 .mu.m. Specifically, the powder particles have an average particle size with a value of greater than 0.1 .mu.m and in particular greater than 0.5 .mu.m or greater than 1 .mu.m. In the present case, the mean grain size is understood to mean especially an average value of the grain size distribution.
  • The support structure preferably has a plastic in which the powder particles are embedded. Under embedded is specifically understood here that the powder particles are encapsulated by the plastic material. That The powder particles are, for example, initially introduced into a still viscous plastic compound during production, which then hardens with the optional addition of a curing agent and thus forms a composite structure. In the present case, the composite structure is specifically understood to mean that the plastic and the powder particles, which are preferably embedded in individual layers, form a cohesive bond, so that the plastic is interspersed with the powder particles. As a plastic, for example, a thermoplastic is used.
  • The plastic is expediently a reinforced plastic, for example a fiber-reinforced plastic and especially a glass fiber reinforced plastic (GRP). The plastic is processed by a manufacturing process, for example an injection process or an injection molding process to the already mentioned composite structure of plastic and powder particles. For this purpose, the plastic preferably has a softening point with a value in the range of, for example, 150 ° C to a maximum of 300 ° C. Alternatively, the composite has a Thermoplastic or a multi-component plastic, such as a resin.
  • This allows a simple and cost-effective embedding of the powder particles in a plastic, since standard methods are used for the production.
  • According to an alternative embodiment variant, the carrier structure has a foil-like carrier element, to which the powder particles are applied. In the present case, a sheet-like carrier element is understood to mean especially a flat element in the manner of a closed film having a thickness and a value in the range of, for example, 100 μm to 200 μm. Alternatively, the carrier element has a (fiber) structure. This may be, for example, a woven fabric, a scrim or other fibrous structures such as e.g. (Long) fiber mats. The powder particles are in this case, for example, loosely distributed on the support element, in particular adhesively connected thereto. For this purpose, the carrier element is formed for example as an adhesive film. Alternatively, the powder particles are applied loosely, in particular in the case of a structure of the carrier element in the manner of a fabric, arranged in intermediate regions of the fabric. The individual layers are placed on top of each other during production and pressed.
  • Alternatively or in addition to the listed variants, the carrier element is preferably impregnated with a plastic, for example a resin.
  • Expediently, a plurality of layers of the carrier structure provided with the powder particles are arranged in a layer structure for forming the carrier structure. In the present case, the layer structure is understood as meaning in particular a structure in which a plurality of layers of the carrier structure are stacked on top of one another. Alternatively or additionally, the layer structure is impregnated with a viscous plastic. An essential aspect here is that the film-like support elements are designed to be permeable to the viscous composite plastic. As a result, a complete impregnation of the carrier elements with the composite plastic and a sufficient rigidity and strength of the layer structure is achieved.
  • In general, two design variants for the support structure are possible. On the one hand, a plurality of already described layers of the powder particles are embedded as a support element forming the support structure, for example embedded in the plastic of the support structure, in particular cast. On the other hand, a plurality of layers of the carrier element are formed to the support structure.
  • The advantage of these embodiments is that an individual and application-adapted carrier element and thus an individual carrier structure can be produced by the arrangement of the powder particles on the carrier element and the subsequent layering.
  • According to a preferred development, the layers have different proportions of powder particles. In the present case, different proportions mean, on the one hand, different amounts of powder particles per layer and / or, on the other hand, a different density of powder particles per layer. The advantage of this development can be seen in a variation of the magnetic permeability per layer. In other words: Due to different proportions of powder particles, the different layers have different magnetic permeabilities, which influence the course of the magnetic field lines. Thus, it is achieved, for example, that the layer structure has a low magnetic resistance (meaning good magnetic conductivity) along a layer orientation (along the powder particles distributed on a layer) and a high magnetic resistance (perpendicular to the individual layers) perpendicular to the layer orientation ( means a poor magnetic conductivity). Thus, it is additionally achieved that the field lines are guided in a sliding manner from, for example, a region without powder particles into a region with powder particles. Such areas are, for example, edge areas at the ends of the secondary coil.
  • Preferably, a particle density of the powder particles varies. As a result, the magnetic permeability is varied depending on location. In particular, a distribution of the powder particles within the carrier structure has a density gradient for this purpose. In the present case, a density gradient is specifically understood to mean that the density of the powder particles varies along an extension direction of the carrier structure, so that the carrier structure has a varying permeability along the direction of expansion. In the present case, the term "varying" is understood to mean that the density of the powder particles varies continuously, for example, and in particular does not have any abrupt density changes. In other words, if a function is considered whose graph describes the density of the powder particles along the direction of expansion, a varying density in the present case should be understood in particular to mean that this graph, and in particular its function, has no discontinuities and / or points of discontinuity.
  • In particular, the density gradient and thus the density change of the powder particles embedded within the carrier structure differs from a density change due to manufacturing tolerances, for example of a solid element for example, ferrite or an absolute change in density due to an arrangement of a plurality of solid elements with a gap (between adjacent solid elements) that does not have ferromagnetic material. In the present case, solid elements are understood as meaning mostly sintered and pressed solid solids, for example of ferrite, which have a shape in the manner of a plate or a billet. For example, the solid elements are formed as massive ferrite cores. By solid elements are meant in particular those elements which thus have a size which, for example, by a factor in a range of 10 to 100 is greater than the size of the powder particles. Typically, the solid elements have a size in the millimeter range, for example, with a value in the range of 2mm to 10mm.
  • The advantage of a varying particle density is that an individually adjustable guidance of the magnetic field lines is achieved due to the permeability that varies as a result. In the present case, individually adjustable is especially understood to mean that a desired direction of the guidance of the magnetic field lines can be set by means of the varying particle density.
  • Alternatively or in addition to the varying particle density, varying permeability of the support structure is achieved by varying the thickness of the support structure. As a result, a simple realization of the varying permeability of the support structure is achieved, which also allows the individual guidance of the magnetic field lines. In this case, the carrier structure is formed, for example, as an insert part from the powder particles and embedded in the field guide element, for example embedded in the field guide element according to already described field.
  • To shield as mentioned above, for example, an interior of the motor vehicle against the magnetic field lines, the field guide element is preferably arranged to the interior of the vehicle oriented above the secondary coil. That the field guide element is arranged on the side facing away from the side of the carriageway side of the secondary coil. The arrangement above the secondary coil is hereby considered in a vertical direction. That the field guide element is arranged, for example, between the secondary coil and a bottom element of the interior of the motor vehicle.
  • Alternatively or additionally, a field guide element is additionally arranged on the side of the secondary coil facing the roadway.
  • In an expedient embodiment, the secondary coil is integrated in the field guide element. In particular, the secondary coil is embedded in the field guide element according to the manner already described, for example cast in. As a result, mechanical protection of the secondary coil is achieved in addition to an optimized guidance of the magnetic field lines.
  • Usually, the device has mechanical support elements. Such mechanical support elements are generally holding elements or connecting elements, such as screws, bolts, sleeves or brackets and rails. By means of the support elements, the device is arranged and fixed to the underbody of the motor vehicle. The field guide element is arranged such that it shields the support elements from magnetic fields. For this purpose, the powder particles are expediently distributed around the support element, in a manner distributed over the circumference, in order to "pass" the magnetic field lines and thus the magnetic field on the support element. For example, the powder particles are circumferentially distributed around a screw head of a screw.
  • Such a shield has proven to be suitable to prevent induction of eddy currents within the mechanical fasteners and / or the mechanical support elements. Due to the shielding, the field lines are also guided in such a way that the charging process is optimized.
  • According to an expedient development, the mechanical connecting elements and / or the mechanical carrying elements are integrated into the field guiding element. By integrated is understood in the present case especially with regard to the mechanical connecting elements and / or the mechanical support elements that the field guide element, for example, has a bore through which a connecting element is guided to arrange the field guide element on the subfloor, for example, to screw. The advantage here is that a simple shielding of the mechanical connection elements and / or the mechanical support elements is achieved with a simple arrangement of the field guide element on the subfloor.
  • Conveniently, to guide the magnetic field lines are also solid elements, as described above, arranged. Due to their high permeability, the solid elements serve to reinforce the guidance of the magnetic field lines.
  • According to a preferred embodiment, the solid elements are integrated into the field guide element, in particular embedded in the manner already described.
  • Alternatively, the field guide element connects to a solid element. The advantage of the alternative embodiment can be seen in an optimization of the guidance of the magnetic field lines. In other words, in addition to the guidance by the solid elements, an optimized "transition" of, for example, laterally deflected magnetic field lines of, for example, a vicinity of the coil system into the solid elements is achieved by means of the arrangement of the field guide element and in particular the powder particles. By proximity is meant, for example, an intermediate region between the secondary coil and the ground - thus the area of the ground clearance of the motor vehicle.
  • The solid elements are arranged, for example, also above the secondary coil according to the embodiments described above.
  • For an optimized guidance of the laterally deflected magnetic field lines, the particle density of the field guide element adjoining the solid elements laterally varies in such a way that it decreases toward the outside. Outwardly, in the present case, is understood to mean especially a direction which is oriented away from the coil.
  • A gap is usually formed between the solid elements. Such an embodiment is based on the consideration that large-area solid elements are not formed as a one-piece, in particular not as a monolithic element, but are formed from an arrangement of a number of small-area elements. The advantage of such an arrangement is seen in a reduction in the induction of eddy currents within the solid elements. The gap preferably has a width with a value in the range of a few micrometers to a few millimeters, for example between 1 μm and 1 mm.
  • Usually, however, the magnetic field lines are deflected laterally relative to the solid elements, in particular in a region of the gap. The deflection often leads to the fact that the deflected magnetic field lines induce unwanted eddy currents in a "bottom plate" of the interior or even deflected into the interior.
  • Above the gap - viewed in the vertical direction - therefore the field guide element is preferably arranged. Such an arrangement of the field guiding element serves to guide the magnetic field lines and thus a shielding of an area above the field guiding element, for example the interior of the motor vehicle. However, in order to shield magnetic field lines that propagate above the field-guiding element-but are at least attenuated by the field-guiding element-preferably a distance between the gap and the field-guiding element has a smaller value than a distance between the field-guiding element and a supporting material below the subsoil. In other words, the field guide element is arranged closer to the gap and thus closer to the solid elements than to the bottom plate of the interior or for example to the protective element mentioned above.
  • Furthermore, the field guide element arranged above the gap, in particular the support structure, preferably has a different particle density, such that it has the highest particle density directly above the gap. When viewed in the direction of the ends of the field guiding element, the particle density decreases, for example, continuously or according to a predetermined pattern (in particular adapted to a course of the magnetic field lines).
  • Alternatively or additionally, the field guide element is formed such that it has, for example, a varying thickness. For example, the field guide element has a maximum thickness immediately above the gap. In the direction of the ends of the field guiding element, the thickness of the field guiding element decreases, for example, continuously or according to a predetermined pattern.
  • These two embodiments are based on the consideration that the highest magnetic flux density occurs directly in the region of the gap-based on the flux density which occurs within the solid elements-and decreases as viewed in the direction of the ends of the field-guiding element. Due to this, the magnetic field lines in the region of the gap are strongly laterally deflected. Thus, for a sufficient guidance of the magnetic field lines occurring in the region of the gap, the highest proportion of ferrite within the field guide element is essential.
  • In the case of the embodiment variant relating to the varying particle density, the highest proportion of ferrite is achieved in that the field guide element in this area has the highest density of (ferrite) powder particles.
  • In the case of the embodiment variant relating to the varying thickness of the field guiding element, in particular the carrier structure, the highest proportion of (ferrite) powder particles is achieved by the maximum thickness of the field guiding element occurring in the region of the gap.
  • The advantage of these embodiments is that the occurring magnetic field lines, in particular the magnetic field lines occurring in the region of the gap, are guided sufficiently and especially optimized. Under sufficient and specially optimized in the present case is specifically understood that by means of the design of the field guide element and in particular the support structure by and / or with powder particles, a guidance of the magnetic field lines is achieved depending on their strength.
  • Embodiments of the invention will be explained in more detail with reference to FIGS. These show partly in highly simplified representations:
    • 1 a rough sketch of a support structure with a layer arrangement of powder particles,
    • 2 a sketched block diagram for producing a composite structure of powder particles and plastic,
    • 3a a sketch of a solid element embedded in a field guide element without embedded powder particles,
    • 3b a sketch of the embedded in the field guide element solid element with embedded powder particles,
    • 4 a section of a secondary coil embedded in the field guide element together with a solid element and powder particles,
    • 5 a sketched arrangement of the secondary coil above a primary coil,
    • 6 a plan view of a screw head with circumferentially arranged powder particles and
    • 7 a sketch of the secondary coil with additionally arranged below the secondary coil field guide element.
  • In the figures, like-acting parts are represented by the same reference numerals.
  • For guiding and shielding magnetic field lines F , which are generated when charging an electric motor driven motor vehicle, is usually a device 2 with a field guide element 4 for guiding the magnetic field lines F intended. By the leadership of the field lines F On the one hand, the charging process is optimized and on the other hand (as already mentioned) areas of the motor vehicle, for example an interior space in relation to the field lines F shielded.
  • In 1 is a carrier structure 6 shown, which for guiding and shielding the magnetic field lines F serves. Such carrier structures 6 are usually in the field guide element 4 integrated, specially embedded. For this purpose, the field guide element 4 usually a viscous plastic, for example a fiber-reinforced plastic, into which the support structure 6 is poured. Alternatively, the field guide element 4 in full by a support structure 6 educated. The support structure 6 has a layer arrangement of a number, in the embodiment three, of layers of powder particles 8th on. The powder particles 8th have a ceramic ferrimagnetic material such as ferrite. Due to its high permeability, ferrite has proved to be particularly suitable for guiding and / or shielding magnetic fields while at the same time reducing the induction of lossy eddy currents. In the exemplary embodiment, powder particles are understood to mean especially granular particles having a mean particle size of not more than 200 μm, preferably not more than 100 μm, and especially having a particle size of greater than 0.1 μm and in particular greater than 0.5 μm or greater than 1 μm. Alternatively or additionally, under powder particles 8th referring also understood powder platelets. Such powder platelets are, for example, pressed into a mold, but in particular not materially bonded, powder particles. The powder platelets have easier handling and thus processing than the pure loose powder particles 8th , Furthermore, the powder particles 8th in contrast to so-called solid-state ferrites not connected to each other, for example, by a sintering process and thus form in particular a loose structure. Such solid-state ferrites are also referred to as solid (ferrite) elements 12. Such solid elements 12 usually have a permeability with a value greater 200 on. This high permeability is due for example to the sintering process for the production of the resulting high material density.
  • In addition, the support structure has 6 in the exemplary embodiment, four layers of a film-like carrier element 10 on. The carrier element 10 has, for example, a fabric or a film. For distribution on the carrier element 10 become the powder particles 8th for example, scattered loose on this. Adhesion of the powder particles 8th is for example by a trained as an adhesive sheet carrier element 10 ensured. Alternatively, the support structure 6 pressed and / or impregnated with a viscous plastic, such as a resin, so that after curing the powder particles 8th with the carrier element 10 are connected. An important aspect here is that the carrier element 10 must be permeable to the plastic to ensure high strength and stability of the support structure 6 to ensure in the cured state.
  • Alternatively or additionally, the powder particles 6 in the viscous plastic of the field guide element 4 embedded, in particular cast, for example in the manner of an injection molding process.
  • Furthermore, such composite structures of powder particles and plastic are alternatively stacked on each other and thus form the support structure 6 out.
  • Common is to guide the magnetic field lines F application-specific a direction and or a course of the field lines given. This course of the field lines F is by means of, for example, different thicknesses or lateral expansions in a longitudinal direction X the powder particles feasible. In other words, a desired or predetermined course of the field lines F by means of the support structure 6 To achieve this, for example, this has different lengths in the longitudinal direction X extending layers with powder particles 8th on. The support structure 6 in the exemplary embodiment has a geometrical arrangement of the powder particles 8th in the manner of a pyramid or a trapezoid.
  • As a result, the magnetic resistance of the powder particle layers is varied and the field lines F show a different course through the individual layers. By a suitable choice of the number of powder particle layers and / or the expansion of the powder particles 8th per layer in the longitudinal direction X is a guide, in particular a "steering" of the field lines F reached. In this way, in particular the charging process can be optimized to the effect that lateral to the orientation of the magnetic field lines F deflected field lines F For example, be directed in the direction of a charging coil and thus less losses.
  • In 2 is a sketched block diagram for producing the composite structure of powder particles and plastic shown. In the exemplary embodiment, the production takes place in the manner of an injection molding process. Here are the individual components, in this case the powder particles 8th and a plastic to be mixed K , first in a mixing head 24 poured, in which both components 8th , K are heated. Plastic K melts and becomes with the powder particles 8th mixed. Alternatively, the plastic K heated before it enters the mixing head 24 is poured.
  • Subsequently, the still viscous but with the powder particles 8th interspersed plastic K P for example, poured into a mold and cured.
  • To better illustrate a principle of action of the powder particles 8th within the carrier structure 6 of the field guide element 4 is in 3a a field guide element 4 with two embedded solid elements 12 on. The solid elements 12 are for example for embedding in the field guide element 4 poured into a viscous plastic. Typically, the part of the field guide element becomes 4 , which is filled by the viscous plastic also called potting compound 14 designated. Often a secondary coil 16 (see. 4 ) of the charging system also in the viscous plastic of the field guide element 4 poured to protect them from shock and vibration of the driving operation of the motor vehicle. The secondary coil 14 generally serves to charge a battery of the motor vehicle by inducing a voltage in it. The voltage is due to the generated by a primary coil magnetic alternating field, which is the secondary coil 16 is suspended in the secondary coil 16 induced.
  • A risk of breakage of the usually brittle solid elements 12 by reducing mechanical loads are instead of a single solid element 12 often several solid elements 12 on or in the field guide element 4 arranged. In each case between two ends of adjacent solid elements 12 is thus a gap 18 formed by the field guide element 4 and especially the solid elements 12 have an elasticity to compensate for occurring mechanical loads.
  • During charging indicates the magnetic flux density B between in the gap 18 a higher value than inside the solid elements 12 , Due to this, the magnetic field lines become in the region of the gap 18 lateral to the solid elements 12 in and against a vertical direction V deflected and induce in a supporting material 20 Eddy currents. Under the support material 20 is preferably understood a support or holding element, for example made of aluminum, by means of which the device 2 is arranged on an underbody of the motor vehicle. Such eddy currents are undesirable due to their loss of liability and to avoid.
  • In 3b is a field guide element 4 according to 3a shown. However, it is in an intermediate area 22 of the field guide element 4 the support structure 6 with powder particles 8th arranged. In the exemplary embodiment, the support structure 6 such in the intermediate area 22 arranged that they are centered over the gap 18 is arranged. For this purpose, the support structure 6 For example, in the field guide element 4 , in particular in the already mentioned potting compound 14 embedded, for example, by this poured.
  • During charging, the magnetic field lines become F now so distracted and through the support structure 6 guided, so the field lines F no longer in the support material 20 penetrate and there no eddy currents W be induced more. The charging process is thereby optimized insofar that in accordance with the arrangement 3a occurring losses due to eddy currents W used to charge the battery.
  • For a uniform course of the field lines F along a length L the support structure 6 to reach, has the support structure 6 According to a first embodiment variant in the embodiment, a varying thickness D on. In particular, the support structure 6 immediately above the gap 18 a maximum thickness. Towards the ends of the support structure 6 takes the thickness D from. This embodiment is based on the idea that directly in and above the gap 18 a maximum flux density B occurs, which in the direction of the ends of the support structure, ie in and against the longitudinal direction X decreases. By the decrease of the thickness D the support structure and thus also a thickness of the powder particles 8th , is a magnetic resistance carrier structure 6 and thus the support structure 6 even on the course of out of the magnetic flux density B resulting field lines F Voted.
  • Alternatively, the support structure 6 According to a second embodiment variant, a constant thickness D along the length L on. However, the support structure has 6 in the alternative embodiment variant on a density gradient. That is the density of powder particles 8th within or on the support structure 6 points, for example, immediately above the gap 18 a maximum value. Towards the ends of the support structure 6 takes the density of powder particles 8th which reduces the magnetic resistance of the support structure 6 is varied and thus an adaptation to the varying flux density B within the solid elements 12 is ensured.
  • In 4 is a section of the device 2 with the field guide element 4 for guiding the magnetic field lines F in a border area R the secondary coil 16 shown. In the potting compound 14 of the field guide element 4 is a solid element 12 embedded, to which at one end the support structure 6 from powder particles 8th followed. In the exemplary embodiment, the support structure 6 a shape in the manner of a triangle, in the manner previously described by a variation of the thickness D to vary the magnetic resistance. Due to the shape and in particular due to the varying magnetic resistance of the support structure 6 , be on the support structure 6 impinging field lines F in the direction of the secondary coil 16 deflected, whereby the charging process optimized and at the same time an induction of eddy currents in the support material 20 is prevented.
  • 5 shows a sketched arrangement of the secondary coil 16 above a primary coil 26 and the course of the magnetic field lines F while charging. The spools 16 . 26 form a coil system S for loading a motor vehicle. The primary coil 26 is in the embodiment in the ground 28 for example, arranged in the area of a designated parking lot. The two coils 16 . 26 are usually formed as flat spiral coils, so that they are in the vertical direction V have the smallest possible extent. The secondary coil 16 is in the field guide element 4 integrated, embedded, for example.
  • Further clarified 5 a deflection of the magnetic field lines F in the border area R of the coil system S lateral to a central area M of the coil system S , For (re-) guiding the deflected field lines F are for example the powder particles 8th according to 4 at the edge R of the coil system S arranged.
  • In 6 is a plan view of a mechanical support element 30 , In the exemplary embodiment, a hexagonal screw made of a metal, such as stainless steel or aluminum represented. The carrying element 30 is in the embodiment in the field guide element 4 integrated, so it's from the powder particles 8th the support structure 6 Surrounded on the circumference. The peripheral arrangement of the powder particles 8th serves to shield the support element 30 , Ie that the magnetic field lines F on the support element 30 be passed as they instead of through the support element 30 by the more magnetically conductive powder particles 8th flow.
  • 7 shows a sketched representation of the secondary coil 16 with additional below the secondary coil 16 arranged field guide element 4 , Both above the secondary coil 16 arranged field guide element 4 as well as below the secondary coil 16 arranged field guide element 4 have the support structure 6 with powder particles 8th to guide the field lines F on.
  • LIST OF REFERENCE NUMBERS
  • 2
    contraption
    4
    Field guide element
    6
    support structure
    8th
    powder particles
    10
    support element
    12
    Solid element
    14
    potting compound
    16
    secondary coil
    18
    gap
    20
    support material
    22
    intermediate area
    24
    mixing head
    26
    primary coil
    28
    ground
    30
    mechanical support element
    B
    magnetic river
    D
    Thickness of the carrier element
    F
    magnetic field lines
    K
    plastic to be mixed
    kp
    plastic interspersed with powder particles
    L
    Length of the support structure
    M
    mid-range
    R
    border area
    S
    coil system
    V
    vertical direction
    W
    eddy currents
    X
    longitudinal direction
  • QUOTES INCLUDE IN THE DESCRIPTION
  • This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.
  • Cited patent literature
    • DE 102013226830 A1 [0002, 0005, 0015]

Claims (17)

  1. Device (2) for guiding magnetic field lines (F) of a coil system designed for charging a motor vehicle driven by a motor having a secondary coil (16) arranged in the motor vehicle, wherein a field-guiding element (4) is provided for guiding the field lines (F), characterized in that the field guiding element (4) comprises powder particles (8) made of a ferromagnetic material which are distributed in or on a carrier structure (6) which consists at least partially of plastic.
  2. Device (2) according to the preceding claim, characterized in that the powder particles (8) has an average particle size of not more than 200 μm, preferably of not more than 100 μm and more preferably of not more than 50 μm.
  3. Device (2) according to one of the two preceding claims, characterized in that the support structure (6) comprises a plastic, in which the powder particles (8) is embedded.
  4. Device (2) according to one of Claims 1 to 2 , characterized in that the carrier structure (8) comprises a film-like carrier element (10), to which the powder particles (8) are applied.
  5. Device (2) according to the preceding claim, characterized in that a plurality of layers of the powder particles (8) provided with support structures (8) are arranged in a layer structure.
  6. Device (2) according to the preceding claim, characterized in that the layers have different proportions of powder particles (8).
  7. Device (2) according to one of the preceding claims, characterized by , a varying particle density of the powder particles (8), in particular in that a distribution of the powder particles (8) within the support structure (6) has a density gradient.
  8. Device according to one of the preceding claims, characterized in that the support structure (6) has a varying thickness.
  9. Device according to one of the preceding claims, characterized in that the field guide element (4) in a vertical direction (V) viewed above the secondary coil (16) is arranged.
  10. Device (2) according to the preceding claim, characterized in that the secondary coil (16) is integrated in the field guide element (4).
  11. Device (2) according to one of the preceding claims, characterized in that it comprises mechanical connection elements and / or mechanical support elements and that the field guide element (4) is arranged such that the connection elements and the support elements are shielded from magnetic fields.
  12. Device (2) according to the preceding claim, characterized in that the connecting elements and / or the support elements of the field guide element (4) are at least partially surrounded.
  13. Device (2) according to one of the preceding claims, characterized in that for guiding the magnetic field lines (F) and ferromagnetic solid elements (12) are arranged.
  14. Device (2) according to the preceding claim, characterized in that the solid elements (12) in the field guide element (4) are integrated.
  15. Device (2) according to Claim 14 , characterized in that the field guiding element (4) connects to a solid element (12).
  16. Device after Claim 14 , characterized in that between two solid elements (12), a gap (18) is formed and that the field guide element (4) above the gap (18) is arranged.
  17. Method for producing a device (2) for guiding magnetic field lines (F) of a coil system designed to charge a motor vehicle driven by a motor vehicle having a secondary coil (16) arranged in the motor vehicle, a field-guiding element (4) being arranged to guide the field lines (F), characterized in that the field guiding element (4) powder particles (8) which are distributed in or on a support structure (6) which consists at least partially of plastic.
DE102017217990.2A 2017-10-10 2017-10-10 Device for guiding magnetic field lines of a coil system and method for manufacturing Pending DE102017217990A1 (en)

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Application Number Priority Date Filing Date Title
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Application Number Priority Date Filing Date Title
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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102011116246A1 (en) * 2011-10-18 2013-04-18 Audi Ag Secondary transformer unit for attachment to an electric and electric vehicle
US20140209691A1 (en) * 2011-09-11 2014-07-31 David Finn Selective deposition of magnetic particles and using magnetic material as a carrier medium to deposit nanoparticles
DE102013007851A1 (en) * 2013-05-08 2014-11-13 Sew-Eurodrive Gmbh & Co Kg System, in particular for contactless energy transmission
DE102013226830A1 (en) 2013-12-20 2015-06-25 Bayerische Motoren Werke Aktiengesellschaft Arrangement of an induction coil on an underbody of a motor vehicle

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20140209691A1 (en) * 2011-09-11 2014-07-31 David Finn Selective deposition of magnetic particles and using magnetic material as a carrier medium to deposit nanoparticles
DE102011116246A1 (en) * 2011-10-18 2013-04-18 Audi Ag Secondary transformer unit for attachment to an electric and electric vehicle
DE102013007851A1 (en) * 2013-05-08 2014-11-13 Sew-Eurodrive Gmbh & Co Kg System, in particular for contactless energy transmission
DE102013226830A1 (en) 2013-12-20 2015-06-25 Bayerische Motoren Werke Aktiengesellschaft Arrangement of an induction coil on an underbody of a motor vehicle

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