DE102020207703A1 - Power module for operating an electric drive for a vehicle and method for producing such a power module - Google Patents

Abstract

Power module (100) for operating an electric drive for a vehicle, comprising a multi-layer circuit carrier substrate with a first substrate layer (112) and a second substrate layer (114) which is spaced from the first substrate layer (112) in a vertical direction; a first metallization layer (116) which is arranged on a side of the first substrate layer (112) remote from the second substrate layer (114), a plurality of power switches (134, 136, 138, 140) and electrodes ( 142, 144, 146, 148, 150, 152) for controlling the circuit breakers (134, 136, 138, 140); a second metallization layer (118) which is arranged on a side of the second substrate layer (114) remote from the first substrate layer (112); and a third metallization layer (120) disposed between the first and second substrate layers (116, 118).

Description

TECHNICAL AREA

The present invention relates to the field of electromobility, in particular the power modules for operating an electric drive for a vehicle.

TECHNICAL BACKGROUND

Power modules, in particular integrated power modules, are increasingly being used in motor vehicles. Such power modules are used, for example, in DC / AC inverters, which are used to energize electrical machines such as electric motors with a multiphase alternating current. A direct current generated from a DC energy source, such as a battery, is converted into a multiphase alternating current. The power modules are based on power semiconductors, in particular transistors such as MOSFETs and HEMTs.

Typically, such power semiconductors are made from a ceramic carrier substrate which has a metallization plane on the top and bottom. The ceramic substrate serves as an electrical insulation layer between the two metallization levels.

One metallization level serves as an electrode level, the second usually as a contact surface for a base plate connection, a heat sink connection or the like.

However, the one-dimensional electrode plane has the disadvantage that the electrode plane cannot overlap for different currents. This results in a high leakage inductance. Another disadvantage is that, in the case of an inverter, the current conduction for positive and negative DC currents must take place next to one another, which makes it necessary to dimension the carrier substrate.

The invention is therefore based on the object of providing a power module in which the disadvantages described above are at least partially overcome.

This object is achieved by a power module and the use of such a power module in a vehicle according to the independent claims.

The power module in the context of this invention is used to operate an electric drive of a vehicle, in particular an electric vehicle and / or a hybrid vehicle. The power module is preferably used in a DC / AC inverter. In particular, the power module is used to energize an electric machine, for example an electric motor and / or a generator. A DC / AC inverter is preferably used to generate a multiphase alternating current from a direct current generated by means of a DC voltage from an energy source, for example a battery.

The inverter generally has one or more power modules, an intermediate circuit capacitor and a cooler. An input-side connection for coupling in an input current generated by means of an energy source and an output connection for coupling out an output current generated based on the input current can also be arranged in the inverter. In relation to the input current, the power module or the power modules and the intermediate circuit capacitor can be connected in parallel to one another.

The respective power module is based on power semiconductors, from which a bridge circuit arrangement is preferably formed. The bridge circuit arrangement can comprise one or more bridge circuits which are formed, for example, as half bridges. Each half-bridge comprises a high-side switch (HS switch) and a low-side switch (LS switch) connected in series with the high-side switch. Each half bridge is assigned to a current phase of a multiphase alternating current (output current).

The HSS and / or the LSS comprises one or more power semiconductor components such as IGBT, MOSFET or HEMT. The semiconductor material on which the HSS or LSS is based preferably comprises a so-called wide-bandgap semiconductor (semiconductor with a large band gap) such as silicon carbide (SiC) or gallium nitride (GaN).

According to the invention, a multilayer circuit carrier substrate is used in the power module, which comprises two substrate layers spaced apart from one another in the vertical direction. The power module further comprises three metallization layers. A first metallization layer is arranged on a first outer side (for example top side) of the power module. A second metallization layer is arranged on a second outer side (for example underside) of the power module. A third (middle) metallization layer is arranged between the first and second metallization layers such that a first substrate layer is arranged between the first and third metallization layers, a second substrate layer being arranged between the second and third metallization layers. At the first (top) A plurality of power switches and an electrode for controlling the power switch are connected to the metallization layer. The first metallization layer therefore forms a directly contacted metallization layer of the power module. A base plate and / or a heat sink can be connected to the second (underside) metallization layer.

The substrate layers are preferably formed from ceramic. The metallization layers are preferably formed from copper. This enables an inexpensive power module.

By means of a multilayer circuit carrier substrate, it is possible to relocate a current path into a lower level, namely into the third metallization layer. With the same current density, the cross section of the power module can therefore be reduced. This enables more compact power modules to be implemented. As a result, a space-optimized drive inverter can be provided.

Furthermore, the middle current level (middle metallization layer) also serves as a heat spreading and heat capacity. This reduces the thermal resistance of the power semiconductor module. In addition, the EMC damping properties of the power module can be improved with the help of the middle metallization layer.

Furthermore, because the directly contacted metallization layer is not the middle but rather the top metallization layer, the direct contacting of the power module is particularly simple and possible with reduced effort.

Advantageous refinements and developments are specified in the subclaims.

According to one embodiment, a current input and / or a current output are formed in the first metallization layer.

In the case of an inverter, the current input is used to feed in an input current that is a direct current (DC current) generated by a DC voltage from an energy source, such as a battery. With the help of the power semiconductors or a bridge circuit comprising them, the direct current is converted into a multiphase alternating current. The alternating current can be tapped at the current output.

According to a further embodiment, the current input has at least one positive contact and at least one negative contact, which is horizontally spaced from the at least one positive contact.

The positive contacts are used to connect a positive pole of the current input. The negative contacts are used to connect a negative pole of the current input. This enables the power module to be contacted in a simple manner.

According to a further embodiment, a first positive contact, which faces the current output, is spaced apart from a second positive contact along a longitudinal direction.

A plurality of vertical through openings are preferably formed in a first via region of the first substrate layer below the first positive contact. The vertical through-openings are formed in that the first substrate layer in the first via region has a plurality of sections that are horizontally spaced from one another.

A third metallization layer is preferably present between the first and second substrate layers, which is connected to the first positive contact via metallization sections located in the vertical through openings. This enables the first positive contact to be plated through. The plurality of vertical through openings can have different widths.

According to a further embodiment, a plurality of vertical through openings are formed in a second via region of the first substrate layer below the second positive contact.

In this way, a through-hole connection of the second positive contact is made possible analogously to the first plated-through hole region.

According to a further embodiment, at least one first power switch is arranged on the first positive contact.

The first power switch is preferably a high-side switch (HS switch) of a half-bridge, which also includes a low-side switch (LS switch). Such a half bridge or circuit breaker pair is preferably assigned to a current phase of the polyphase alternating current to be generated on the output side. This enables a space-saving design of the power module.

According to a further embodiment, the current output has one of the at least a negative contact facing away from the first positive contact side on a first output contact, wherein the current output also has a second output contact between the first positive contact and the second positive contact ..

The first output contact conducts the current (DC current) fed in on the current input side into a consumer, such as an electric machine, after the input current has flowed through a first power switch (HV switch) arranged on the first positive contact. The second output contact is used to return the fed-in current after it has flowed through the consumer. A plurality of second power switches (such as LS switches) into which the returned current can flow can be arranged on the second output contact. The number of second circuit breakers preferably corresponds to the number of first circuit breakers accommodated on the first positive contact (for example HV switches). In this way, a space-optimized power module for generating a polyphase alternating current is provided.

According to a further embodiment, a plurality of negative contacts are arranged along a transverse direction.

The number of negative contacts preferably corresponds to the number of circuit breaker pairs. Alternatively or additionally, the second positive contact is arranged between two negative contacts. In this way, space-saving contacting of the half bridges is made possible.

• 1 eine schematische Darstellung eines Schichtaufbaus für ein Leistungsmodul gemäß einer Ausführungsform;
• 2 eine schematische Darstellung eines Leistungsmoduls gemäß einer weiteren Ausführung in einer Draufsicht;
• 3 eine schematische Darstellung des Leistungsmoduls aus 2 in einer ersten Schnittansicht; und
• 4 eine schematische Darstellung des Leistungsmoduls aus 2 in einer zweiten Schnittansicht.

Embodiments will now be described by way of example and with reference to the accompanying drawings. Show it:

• 1 a schematic representation of a layer structure for a power module according to an embodiment;
• 2 a schematic representation of a power module according to a further embodiment in a plan view;
• 3 a schematic representation of the power module 2 in a first sectional view; and
• 4th a schematic representation of the power module 2 in a second sectional view.

In the figures, the same reference symbols relate to the same or functionally similar reference parts. The relevant reference parts are identified in the individual figures.

1 shows a schematic representation of a layer structure 10 for one power module. The layer structure 10 has a multi-layer substrate which has a first substrate layer 12th and a second substrate layer 14th includes. The layer structure 10 also has three layers of metallization 16 , 18th , 20th on. A first layer of metallization 16 is on top of the first substrate layer 12th arranged. A second layer of metallization 20th is on the underside of the second substrate layer 14th arranged. A third layer of metallization 18th is between the first and second substrate layers 12th , 14th arranged.

The first and second substrate layers 12th , 14th serve as an insulating layer around an electrical current line between the individual metallization layers 16 , 18th , 20th first to prevent. The substrate layers are preferably involved 12th , 14th one ceramic layer each. The second substrate layer 14th can, as in 1 can be seen, a greater length than the first substrate layer 12th to have.

2-4 each show a schematic view of a power module 100 according to one embodiment in which the layer structure 10 out 1 Is used. The power module 100 is used, for example, in a DC / AC inverter. The following is the power module 100 described using the example of such an inverter.

Fig, 2 shows the power module 100 in a top view. The power module 100 has multiple electrical contacts and electrodes and circuit breakers. The electrical contacts are in the first metallization layer 116 formed and have a first positive contact 122 , a second positive contact 124 , a first negative contact 130 , a second negative contact 132 , a first output contact 126 and a second output contact 128 on. The positive and negative contacts form a current input of the power module 100 , which can be connected to a positive pole of an energy source, such as a battery. The first output contact 126 as well as the second output contact 128 form a current output that can be connected to a consumer, for example an electric machine.

The circuit breakers include two first circuit breakers 134 , 136 and two second circuit breakers 138 , 140 . The first circuit breakers 134 , 136 are typically designed as high-side switches, while the second power switch 138 , 140 are designed as a low-side switch. IGBT, MOSFET or HEMT can be used for power switches. The semiconductor material used herein can contain silicon, silicon carbide and / or gallium nitride.

The two highside switches 134 , 136 form together with the two low-side switches 138 , 140 a half bridge. By means of targeted switching of the circuit breakers 134 , 136 , 138 , 140 the direct current (DC current) fed in at the current input is converted into a multi-phase alternating current (AC current). The switching operations are such that one of the two HS switches and one of the two LS switches is always in a closed state, while the other HS switch and the other LS switch are in an open state. In this way, the fed-in DC current can always flow through the two closed switches. The HS and LS switches are alternately switched between the closed state and the open state in order to carry out pulse width modulation (PWM).

For example, if the HS switch 134 and the LS switch 140 are closed, with the other HS switch 136 and the other circuit breaker 138 are open, the fed-in DC current initially flows into the first positive contact 122 . There the current is passed through the HS switch 134 routed and via a source electrode 142 (or emitter electrode) in the first output contact 126 directed. There the current flows into the consumer (e.g. electric machine) and then via the second output contact 128 , the LS switch 140 and a drain electrode 152 (or collector electrode) to the first negative contact 130 .

For example, if the other HS switch 136 and the other circuit breaker 138 are closed, with the HS switch 134 and the LS switch 140 are open, the fed-in DC current initially flows into the first positive contact 122 . There the current is passed through the HS switch 136 routed and via a source electrode 144 (or emitter electrode) in the first output contact 126 directed. There the current flows into the consumer and then via the second output contact 128 , the LS switch 138 and a drain electrode 150 (or collector electrode) to the first negative contact 130 .

3 Figure 3 shows a sectional view of the power module 100 along an in 1 shown first section plane AA. In addition to part of the above regarding 1 The components described are the second metallization layer 120 , the third metallization layer 118 , the first substrate layer 112 as well as the second substrate layer 114 in 3 shown. A first via area 113 , which comprises a plurality of vertical through openings, is in the first substrate layer 112 educated. This way is the first positive contact 122 with the third (middle) metallization layer 118 electrically connected. In this way, a further current path can be in a deeper level, namely the middle metallization layer 118 , to be provided. With a constant current density, there is a smaller current-conducting cross-sectional area of the power module 100 necessary. This enables a space-optimized power module 100 and finally a more compact drive inverter.

The middle power level (middle metallization layer 118 ) additionally as heat spreading and heat capacity. This reduces the thermal resistance of the power module. In addition, with the help of the middle metallization layer 118 the EMC attenuation properties of the power module 100 be improved.

4th Figure 3 shows a sectional view of the power module 100 along an in 1 shown second section plane BB. Here, too, are the second metallization layer 120 , the third metallization layer 118 , the first substrate layer 112 as well as the second substrate layer 114 in 3 shown. A second via area 115 , which comprises a plurality of vertical through openings, is in the first substrate layer 112 educated. In this way the second is positive contact 124 with the third (middle) metallization layer 118 electrically connected. Analogous to the first via area 113 Here, too, a further current path can be used in a lower level, namely the middle metallization layer 118 , to be provided. This enables a space-optimized power module 100 and finally a more compact drive inverter. The thermal resistance of the power module is also determined by the middle metallization layer 118 , which also acts as a heat spreader, is reduced. Also the EMC attenuation properties of the power module 100 are made with the aid of the multi-layer substrate, in particular that between the two substrate layers 112 , 114 arranged middle metallization layer 118 improved.

List of reference symbols

10

Layer structure

12th

first substrate layer

14th

second substrate layer

16

first metallization layer

18th

second metallization layer

20th

third metallization layer

100

Power module

112

first substrate layer

113, 115

Via area

114

second substrate layer

116

first metallization layer

118

second metallization layer

120

third metallization layer

122

first positive contact

124

second positive contact

126

first output contact

128

second output contact

130

first negative contact

132

second negative contact

134, 136, 138, 140

Circuit breaker

142, 144, 146, 148, 150, 152

Electrodes

Claims (11)

A power module (100) for operating an electric drive for a vehicle, comprising: - A multilayer circuit carrier substrate with a first substrate layer (112) and a second substrate layer (114) which is spaced apart from the first substrate layer (112) in a vertical direction; - A first metallization layer (116) which is arranged on a side of the first substrate layer (112) facing away from the second substrate layer (114), a plurality of power switches (134, 136, 138, 140) and electrodes on the first metallization layer (116) (142, 144, 146, 148, 150, 152) are connected to control the circuit breakers (134, 136, 138, 140); - A second metallization layer (118) which is arranged on a side of the second substrate layer (114) facing away from the first substrate layer (112); and - A third metallization layer (120) which is arranged between the first and the second substrate layer (116, 118). Power module (100) Claim 1 , a current input and / or a current output being formed in the first metallization layer (116). Power module (100) Claim 2 wherein the current input has at least one positive contact (122, 124) and at least one negative contact (130, 132) which is horizontally spaced from the at least one positive contact (122, 124). Power module (100) Claim 3 wherein a first positive contact (122) is spaced from a second positive contact (124) along a longitudinal direction. Power module according to Claim 4 wherein a plurality of vertical through openings are formed in a first via region (113) of the first substrate layer (112) below the first positive contact (122). Power module (100) Claim 4 or 5 wherein a plurality of vertical through-openings are formed in a second via region (115) of the first substrate layer (112) below the second positive contact (124). Power module (100) according to one of the Claims 4 until 6th wherein at least a first power switch (134, 136) is arranged on the first positive contact (122). Power module (100) according to one of the Claims 4 until 7th , the current output having a first output contact (126) on a side of the first positive contact (122) facing away from the at least one negative contact (130, 132), the current output further between the first positive contact (122) and the second positive contact (124) has a second output contact (128). Power module (100) Claim 8 , wherein at least one second power switch (138, 140) is arranged on the second output contact (128). Power module (100) according to one of the Claims 3 until 9 wherein a plurality of negative contacts (130, 132) are arranged along a transverse direction. Use of the power module (100) according to one of the preceding claims as an inverter or part thereof in a vehicle, in particular an electric vehicle and / or a hybrid vehicle.

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