DE102022120485A1 - ELECTRONIC ASSEMBLY FOR A HIGH-VOLTAGE BATTERY OF A MOTOR VEHICLE AND METHOD FOR EQUIPPING A HOUSING OF A HIGH-VOLTAGE BATTERY FOR A MOTOR VEHICLE - Google Patents

Abstract

The invention relates to an electronic assembly (10) for a high-voltage battery of a motor vehicle, comprising a circuit board (14) equipped with electronic components (12), on the underside (18) of which an insulation layer (20) designed as high-voltage insulation is arranged, which is the underside ( 18) of the circuit board (14) is at least largely covered and is designed as a contact surface for mounting the electronic assembly (10) to a housing (22) of the high-voltage battery. The invention further relates to a method for equipping a housing (22) of a high-voltage battery for a motor vehicle with at least one such electronic assembly (10).

Description

Technical area

The present invention relates to an electronic assembly for a high-voltage battery of a motor vehicle and a method for equipping a housing of a high-voltage battery for a motor vehicle with at least one such electronic assembly.

State of the art

In electrically powered motor vehicles, the battery cells of a high-voltage battery usually have to be adjusted in terms of their electrical charge distribution, which is also referred to as balancing. So-called balancers are used for this, which can be electronic assemblies that can have special integrated circuits, for example. Such assemblies and their circuits usually have to be thermally cooled on the one hand and electrically insulated on the other, since high-voltage batteries usually have very high voltages.

In addition, the assembly of such electronic assemblies, which are intended to function as balancers, for example, can be quite difficult, since as far as possible no mechanical stress, for example due to twisting or warping, should be applied to such electronic assemblies. In addition, challenges can arise with regard to the thermal dissipation of such electronic assemblies and with regard to electrical insulation. Both of these can make it difficult to assemble such electronic assemblies on a high-voltage battery housing.

Description of the invention

It is the object of the invention to enable particularly simple and effective electrical insulation of an electronic assembly for a high-voltage battery of a motor vehicle.

This task is solved by the subject matter of the independent claims. Further possible embodiments of the invention are disclosed in the subclaims, the description and the figures. Features, advantages and possible configurations set out in the description for one of the subject matter of the independent claims are at least analogous to the features, advantages and possible embodiments of the respective subject matter of the other independent claims and any possible combination of the subject matter of the independent claims, if applicable in conjunction with one or more of the subclaims.

The electronic assembly according to the invention for a high-voltage battery of a motor vehicle comprises a circuit board equipped with electronic components, on the underside of which an insulation layer designed as high-voltage insulation is arranged, which at least largely covers the underside of the circuit board and is designed as a contact surface for mounting the electronic assembly on a battery housing of the high-voltage battery is. By at least largely it is meant that the insulation layer designed as high-voltage insulation covers more than half of the underside of the circuit board. This can also be understood to mean that the insulation layer designed as high-voltage insulation completely covers the underside of the circuit board. Values in between, i.e. from a coverage of over 50% to 100%, are possible. In particular, all electrically conductive parts of the underside of the circuit board can be covered by the insulation layer. The insulation layer designed as high-voltage insulation can in particular be flat or flat, in particular on its outside, which serves to arrange the electronic assembly, in particular on the outside of the battery housing of the high-voltage battery in question.

The underside of the circuit board can be the side facing away from the electronic components. The outside of the insulation layer can be the side of the insulation layer facing away from the underside of the circuit board. The electronic components can be mounted on a top side of the circuit board. In addition, the electronic assembly can also have electrical components. The printed circuit board can be a so-called PCB. In other words, the circuit board can be a printed circuit, also known as a printed circuit board. The circuit board can be a single-layer or a multi-layer PCB. The electronic components located on the top can be connected to the corresponding circuits of the individual layers, for example by drilling plated holes in the desired layer.

In other words, the electronic assembly is a populated circuit board, which also has an insulation layer designed as high-voltage insulation on the underside of the circuit board. Since the electronic assembly is designed for use in or on a high-voltage battery, high-voltage insulation plays a particularly important role. In the invention it is intended to relocate the electrical insulation in or on the circuit board, namely in the form of High-voltage insulation designed insulation layer, which is provided on the underside of the circuit board. In particular, this insulation layer cannot be part of the circuit board, but rather a separate layer. In contrast to the invention, a relatively large amount of gap filler and often several insulating films are traditionally used, which are arranged between such electronic assemblies and a battery housing of a high-voltage battery in order to electrically isolate the electronic assembly from the housing of the high-voltage battery, which is usually made of metal. This makes the attachment or assembly of such electronic assemblies on the housing of a high-voltage battery very complex.

In the case of the electronic assembly according to the invention, however, the insulation layer designed as high-voltage insulation is already part of the electronic assembly. In other words, high-voltage insulation is provided directly on the circuit board of the electronic assembly. The electronic assembly can therefore be easily attached to the relevant housing of the high-voltage battery by attaching the electronic assembly with its insulation layer designed as high-voltage insulation directly or indirectly to the outside of the housing. It is no longer necessary to provide further measures for electrically insulating the electronic assembly from the housing of the high-voltage battery, since the high-voltage insulation in the form of the said insulation layer is already an integral part of the electronic assembly according to the invention.

In contrast to common methods, it is no longer necessary, for example, to provide protective films, insulating varnishes or the like before or during assembly of the electronic assembly on the housing of the high-voltage battery. By means of the electronic assembly according to the invention, a particularly simple and effective electrical insulation of the electronic assembly from a housing of a high-voltage battery is made possible.

A possible embodiment of the electronic assembly provides that the electronic assembly is designed to ensure a uniform electrical charge distribution in at least some battery cells of the high-voltage battery when the electronic assembly is electrically connected to the high-voltage battery. In other words, the electronic assembly can be a so-called balancer or the electronic assembly can be designed to function as a balancer. The said electronic components with which the circuit board of the electronic assembly is equipped can, for example, have correspondingly suitable circuits and also other electrical and/or electronic components. Especially when the electronic assembly functions as a balancer, both the high-voltage insulation and the thermal cooling of the electronic assembly play a particularly important role. Because the underside of the circuit board is at least largely covered by the insulation layer designed as high-voltage insulation, particularly reliable electrical insulation of the electronic assembly from the housing and from the rest of the high-voltage battery can be ensured. The insulation layer designed as high-voltage insulation also serves as a contact surface for mounting the electronic assembly on the battery housing of the high-voltage battery and can be designed or formed in such a way that particularly good, reliable thermal heat dissipation, in particular of the electronic components of the electronic assembly, can be made possible during operation. This can ensure that the electronic assembly does not overheat, especially if it functions as a balancer for the high-voltage battery in question.

A further possible embodiment of the invention provides that the insulation layer designed as high-voltage insulation can ensure insulation up to 3.5 kV. This makes it possible to ensure particularly reliable high-voltage insulation through the insulation layer during operation of the electronic assembly, i.e. when it is mounted on the said high-voltage battery.

According to a further possible embodiment of the invention, it is provided that the insulation layer comprises polyimide. Polyimides have particularly good properties in terms of electrical insulation. It can also be provided that the insulation layer consists of polyimide.

In a further possible embodiment of the invention, it is provided that the insulation layer is between 25 and 50 μm thick. This can be provided in particular in connection with the insulation layer comprising polyimide. The heat transfer from the electronic assembly, in particular from its electronic components, to the relevant housing of the high-voltage battery can be ensured due to the very thin insulation layer, which is only between 25 and 50 µm thick. At the same time, this thickness ensures reliable high-voltage insulation.

According to a further possible embodiment of the invention, it is provided that the insulation layer is laminated onto the underside of the circuit board. The production and assembly of the printed circuit board of the electronic assembly can can be done quite conventionally, after which the polyimide material is then laminated onto the underside of the circuit board. This can be done both at the circuit board manufacturer and in a downstream process step, for example at an automotive supplier. By laminating, the insulation layer can be applied to the underside of the circuit board in a particularly simple and reliable manner. A large part of the underside of the circuit board can be provided with the insulation layer.

An alternative possible embodiment of the invention provides that the insulation layer comprises FR4 or is made from FR. FR4 refers to a class of flame-retardant and flame-retardant composite materials consisting of epoxy resin and fiberglass fabric. The abbreviation FR stands for Flame Retardant. FR4 typically has a fairly high dielectric strength, for example in the range of 20 to 60 kV/mm. Because the insulation layer comprises FR4 or is made from it, it can ensure particularly reliable high-voltage insulation.

In a further possible embodiment of the invention, it is provided that the FR4 comprises or is a no-flow prepreg. In this context, it can be provided that the insulation layer made of FR4 is laminated to the underside of the circuit board. Because the FR4-comprising insulation layer has or consists of a no-flow prepreg, it can be ensured during the lamination process that the insulation layer retains its shape during the lamination process. This can ensure, among other things, that the insulation layer maintains the desired layer thickness or has it even after the lamination process. The insulation layer comprising FR4 can be, for example, 50 µm to 150 µm thick. This can ensure, on the one hand, particularly good high-voltage insulation and, on the other hand, good heat dissipation from the electronic assembly, in particular its electronic components, to the housing of the high-voltage battery.

An alternative possible embodiment of the invention provides that the insulation layer is pressed onto the underside of the circuit board. If the circuit board is a multi-layer circuit board, its layers can first be produced, after which, for example, the insulation layer comprising FR4 can be pressed, drilled and plated through with the remaining layers. By pressing the insulation layer onto the underside of the circuit board, a particularly simple and reliable connection between the insulation layer and the circuit board can be ensured.

In the method according to the invention for equipping a housing of a high-voltage battery for a motor vehicle, at least the electronic assembly according to the invention or a possible embodiment of the electronic assembly is attached to the battery housing of the high-voltage battery, with the insulation layer designed as high-voltage insulation being arranged on the battery housing directly or with the aid of a gap filler. The insulation layer designed as high-voltage insulation can be arranged directly on the battery housing, i.e. without any additional material in between. Alternatively, it is possible to provide a gap filler between the insulation layer designed as high-voltage insulation and the battery housing, in particular no other material, i.e. only the gap filler. In addition to compensating for unevenness, the gap filler can serve to connect, in particular to glue, the insulation layer designed as high-voltage insulation to the battery housing, so that the insulation layer is connected to the battery housing via the gap filler. The electronic assembly can be arranged on the outside or inside of the housing of the high-voltage battery. It is also possible, in the course of the method or in the course of equipping the housing of the high-voltage battery, to arrange several of the electronic assemblies on the battery housing with their respective insulation layers designed as high-voltage insulation. Equipping the housing of the high-voltage battery with the electronic assembly is particularly simple because the electrical insulation is completely relocated to the electronic assembly, namely because the insulation layer designed as high-voltage insulation is part of the electronic assembly. This means that no further precautions need to be taken when equipping the housing in order to electrically shield or insulate the electronic assembly from the battery housing. Otherwise complex measures for electrical insulation can therefore be omitted; for example, it is not necessary to apply a protective film to the electronic assembly, to provide the battery housing with an insulating varnish or a film, for example, and the like. Overall, the method according to the invention results in a particularly simple and reliable electrical insulation of the electronic assembly from the housing of the high-voltage battery.

Further advantages, features and details of the invention can be found in the following description of possible exemplary embodiments and in the drawing. The front one Features and feature combinations mentioned in the description as well as the features and feature combinations shown below in the description of the figures and/or in the figures alone can be used not only in the combination specified in each case, but also in other combinations or on their own, without departing from the scope of the invention leave.

Short character description

• 1 eine schematische Draufsicht auf eine Oberseite einer elektronischen Baugruppe für eine Hochvoltbatterie eines Kraftfahrzeugs, die eine mit elektronischen Komponenten bestückte Leiterplatte aufweist;
• 2 eine schematische Seitenansicht der elektronischen Baugruppe, wobei eine als Hochvoltisolierung ausgelegte Isolationsschicht zu erkennen ist, die an der Unterseite der Leiterplatte angeordnet ist;
• 3 eine schematische Draufsicht von unten auf die elektronische Baugruppe, sodass die als Hochvoltisolierung ausgelegte Isolationsschicht zu erkennen ist; und
• 4 eine schematische Darstellung eines Gehäuses einer Hochvoltbatterie, wobei mehrere der elektronischen Baugruppen außenseitig am Gehäuse der Hochvoltbatterie.

The drawing shows in:

• 1 a schematic top view of a top side of an electronic assembly for a high-voltage battery of a motor vehicle, which has a circuit board equipped with electronic components;
• 2 a schematic side view of the electronic assembly, showing an insulation layer designed as high-voltage insulation, which is arranged on the underside of the circuit board;
• 3 a schematic top view from below of the electronic assembly, so that the insulation layer designed as high-voltage insulation can be seen; and
• 4 a schematic representation of a housing of a high-voltage battery, with several of the electronic assemblies on the outside of the housing of the high-voltage battery.

In the figures, identical or functionally identical elements are provided with the same reference numerals.

An electronic assembly 10 for a high-voltage battery of a motor vehicle, not shown here, is shown in a top view from above 1 shown. The electronic assembly 10 includes a printed circuit board 14 equipped with electronic components 12. For the sake of clarity, not all electronic components have been given reference numbers. Some of the electronic components may be, for example, integrated circuits. The electronic assembly 10 is designed to ensure a uniform electrical charge distribution in at least some of the battery cells of the relevant high-voltage battery on which it can be mounted. In other words, the electronic assembly 10 can function as a balancer.

In 2 the electronic assembly 10 is shown in a schematic side view. As indicated here, the circuit board 14 can consist of several layers. The electronic components 12 are not shown here. While - as in 1 to recognize - the electronic components 12 are arranged on a top side 16 of the circuit board 14, an insulation layer 20 designed as high-voltage insulation is arranged on a bottom side 18 of the circuit board 14. This insulation layer 20 covers the underside 18 of the circuit board 14 at least largely and serves as a contact surface for mounting the electronic assembly 10 on a battery housing of the high-voltage battery in question. The insulation layer 20 can - contrary to the present illustration - also be bordered laterally by one or more layers of the conductive plate 14, for example. The insulation layer 20 can, for example, end at the same height as the rest of the circuit board 14. In other words, the insulation layer 20 and the bottom layer of the circuit board 14 could form an at least substantially flat underside of the electronic assembly 10. Depending on the requirements for the high-voltage insulation and material composition of the insulation layer 20, it can also be so thick that it projects beyond the circuit board 14, for example by a third to half of its own thickness.

In 3 the electronic assembly 10 is shown in a top view from below, so that the large-area and flat insulation layer 20 designed as high-voltage insulation can be seen. The insulation layer 20, designed as high-voltage insulation, can ensure insulation up to 2.5 kV. The insulation layer can be made from polyimide, for example. The insulation layer can be between 25 and 50 µm thick. The insulation layer 20 can, for example, be laminated onto the underside 18 during the production of the electronic assembly 10.

Alternatively, the insulation layer 20 can also be made from FR4. In particular, it can be provided that the insulation layer 20 made of FR4 is a no-flow prepreg. Prepreg is the English short form for Pre Impregnated Fibers. Prepregs are usually semi-finished textile fiber matrix products pre-impregnated with reaction resins that are cured under temperature and pressure to produce components. The insulation layer 20 made from FR4 can be 80 μm thick, for example. The insulation layer 20 can, for example, be laminated onto the underside 18 of the circuit board 14. Alternatively, it is also possible to press the insulation layer 20 onto the underside 18 of the circuit board 14. In terms of manufacturing technology, it can be provided, for example, that initially only the layers of the circuit board 14 are produced, after which the insulation layer 20 is only pressed, drilled and plated through as the fifth layer.

In 4 is a housing 22 of an unspecified high-voltage battery of a motor vehicle shown in a schematic perspective view. Three of the electronic assemblies 10 were attached to an outside 24 of the housing 22. To equip the housing 22 of the unspecified high-voltage battery, the electronic assemblies 10 are attached to the housing 22 of the high-voltage battery, with the insulation layers 20 designed as high-voltage insulation being arranged on the outside of the housing 22 directly or only with the aid of a gap filler. The function of electrical insulation is therefore integrated into the respective electronic assemblies 10, namely in the form of the said insulation layer 20 on the underside 18 of the respective circuit boards 14. When attaching the electronic assemblies 10 to the housing 22, it is therefore not necessary to take additional electrical measures To provide insulation between the electronic assembly 10 and the housing 22. If necessary, a gap filler is provided between the insulation layer 20 and the outside 24 of the housing 22. This can help to enable particularly good heat transfer from the electronic assemblies 10 to the housing 22. Equipping the housing 22 is particularly easy thanks to the integrated additional insulation layer 20 designed as high-voltage insulation. By appropriate material selection and dimensioning with regard to the thickness of the insulation layer 20, both good electrical insulation from the housing 22 and a good thermal connection to the housing 22 can be ensured.

REFERENCE SYMBOL LIST

10

electronic assembly

12

electronic components

14

Circuit board

16

Top of the circuit board

18

Bottom of the circuit board

20

Insulation layer designed as high-voltage insulation

22

Housing of a high-voltage battery

24

Outside of the case

Claims (12)

Electronic assembly (10) for a high-voltage battery of a motor vehicle, comprising a circuit board (14) equipped with electronic components (12), on the underside (18) of which an insulation layer (20) designed as high-voltage insulation is arranged, which forms the underside (18) of the circuit board (14) is at least largely covered and is designed as a contact surface for mounting the electronic assembly (10) on a housing (22) of the high-voltage battery. Electronic assembly (10). Claim 1 , characterized in that the electronic assembly (10) is designed to ensure a uniform electrical charge distribution in at least some battery cells of the high-voltage battery when the electronic assembly is electrically connected to the high-voltage battery. Electronic assembly (10). Claim 1 or 2 , characterized in that the insulation layer (20) designed as high-voltage insulation can ensure insulation up to 3.5 kV. Electronic assembly (10) according to one of the preceding claims, characterized in that the insulation layer (20) comprises polyimide. Electronic assembly (10). Claim 4 , characterized in that the insulation layer (20) is between 25 and 50 µm thick. Electronic assembly (10) according to one of the Claims 1 until 3 , characterized in that the insulation layer (20) comprises FR4. Electronic assembly (10). Claim 6 , characterized in that the FR4 comprises a no flow prepreg. Electronic assembly (10). Claim 6 or 7 , characterized in that the insulation layer (20) is 50 µm to 150 µm thick. Electronic assembly (10) according to one of the preceding claims, characterized in that the insulation layer (20) is laminated onto the underside (18) of the circuit board (14). Electronic assembly (10) according to one of the Claims 1 until 8th , characterized in that the insulation layer (20) is pressed onto the underside (18) of the circuit board (14). Method for equipping a housing (22) of a high-voltage battery for a motor vehicle, in which at least one electronic assembly (10) according to one of the preceding claims is attached to the housing (22) of the high-voltage battery, the insulation layer (20) designed as high-voltage insulation being directly or is arranged on the housing (22) using a gap filler. High-voltage battery with a housing on which an electronic assembly according to one of the preceding claims is arranged with the insulation layer (20) designed as high-voltage insulation.

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