Power module and vehicle

Abstract

The application provides a power module and a vehicle, the power module comprising a substrate and a plurality of power chips; the plurality of power chips are divided into a plurality of power chip groups, the substrate has a plurality of first circuit conductors corresponding to the power chip groups on one side surface of the substrate, the power chip groups are located on the corresponding first circuit conductors, the power chips in the power chip groups are arranged along a first direction, and the input ends of the power chips are connected with the first circuit conductors; the substrate also has second circuit conductors corresponding to the power chip groups on the side surface, the second circuit conductors are located on any one side of the corresponding power chip group column direction, each power chip group also corresponds to a conductive sheet, and the output ends of the power chips in each power chip group are connected to the second circuit conductors corresponding to the power chip group through the conductive sheet corresponding to the power chip group. The application can solve the problems of low conversion efficiency and poor reliability of the power module in the prior art.

Description

Technical Field

[0001] This invention belongs to the field of electronic circuit technology, and more specifically, relates to a power module and a vehicle. Background Technology

[0002] Automotive-grade power modules typically employ a half-bridge circuit, and currently, the vast majority of power modules are primarily packaged using aluminum and copper wires via wirebond. Wirebond packaging results in higher resistance and parasitic inductance. High resistance reduces the power module's conversion efficiency, while high inductance affects its turn-on and turn-off performance, and may even cause overvoltage damage to the chips within the power module.

[0003] Using copper clip technology for power module layout is a good solution. However, the clip packaging method has the following problems: inconsistent parasitic inductance of chips, excessive current in some chips, and easy damage due to large temperature differences; in addition, the contact area of ​​the solder joints in this method is small, making soldering difficult and resulting in poor reliability. Summary of the Invention

[0004] The purpose of this invention is to provide a power module and a vehicle, which aims to solve the problems of low conversion efficiency and poor reliability of power modules in the prior art.

[0005] To achieve the above objectives, a first aspect of the present invention provides a power module, comprising:

[0006] Substrate and multiple power chips;

[0007] Multiple power chips are divided into multiple power chip groups. One side surface of the substrate has multiple first circuit conductors that correspond one-to-one with the power chip groups. The power chip groups are located on the corresponding first circuit conductors. The power chips in the power chip groups are all arranged along a first direction, and the input terminals of the power chips in the power chip groups are all connected to the corresponding first circuit conductors.

[0008] The substrate also has a second circuit conductor corresponding to each power chip group on this side surface. The second circuit conductor is located on any side of the corresponding power chip group column direction. Each power chip group also corresponds to a conductive sheet. The output terminal of the power chip in each power chip group is connected to the second circuit conductor corresponding to the power chip group through the conductive sheet corresponding to the power chip group.

[0009] The substrate also has a DC terminal and an AC terminal on this side surface, and the first circuit conductor and the second circuit conductor are connected to the DC terminal or the AC terminal to form a half-bridge topology.

[0010] Optionally, the DC terminal includes:

[0011] DC positive terminal and DC negative terminal;

[0012] A portion of the first circuit conductor is connected to the DC positive terminal, and the second circuit conductor connected to the power chip group corresponding to the first circuit conductor connected to the DC positive terminal is connected to the AC terminal.

[0013] Another part of the first circuit conductor is connected to the AC terminal, and the second circuit conductor of the power chip group corresponding to the first circuit conductor connected to the AC terminal is connected to the DC negative terminal.

[0014] Optionally, the DC terminal includes:

[0015] DC positive terminal and DC negative terminal;

[0016] A portion of the first circuit conductor is connected to the DC negative terminal, and the second circuit conductor connected to the power chip group corresponding to the first circuit conductor connected to the DC negative terminal is connected to the AC terminal.

[0017] Another part of the first circuit conductor is connected to the AC terminal, and the second circuit conductor of the power chip group corresponding to the first circuit conductor connected to the AC terminal is connected to the DC positive terminal.

[0018] Optionally, the first circuit conductor and conductive sheet are both rectangular structures, with the two opposite sides of the rectangle parallel to the first direction being the long side and the two opposite sides of the rectangle perpendicular to the first direction being the short side;

[0019] The width ratio of the wider side of the first circuit conductor to the wider side of the corresponding conductive sheet is between 0.6 and 1.5.

[0020] Optionally, the number of first circuit conductors connected to the DC positive terminal is equal to the number of first circuit conductors connected to the AC terminal.

[0021] Optionally, each power chipset has the same number of power chips, and the distance between any two adjacent power chips in each power chipset is the same.

[0022] Optionally, the power chip in the power chip group corresponding to the first circuit conductor connected to the DC positive terminal is of type 1, and the power chip in the power chip group corresponding to the first circuit conductor connected to the AC terminal is of type 2; the first type and the second type may be the same or different.

[0023] Optionally, the first type and the second type are diodes or metal-oxide-semiconductor field-effect transistors.

[0024] Optionally, the connection point between the conductor and the conductive sheet in the second circuit adopts a semi-etched structure.

[0025] A second aspect of the present invention provides a vehicle in which various system circuits use power modules as described in the first aspect for power conversion.

[0026] The beneficial effects of the embodiments of the present invention compared with the prior art are as follows:

[0027] The power module of this invention performs clip soldering by placing the second circuit conductor on any side of the corresponding power chip array direction. This ensures that the distance between each chip and the solder joint is the same, resulting in consistent parasitic inductance for each chip, better current sharing, smaller chip temperature difference, and reduced chip damage. Furthermore, this method can increase the area of ​​the conductive sheet and the contact area between the conductive sheet and the second circuit conductor, thereby reducing soldering difficulty, reducing current density, and significantly improving the reliability of the power module. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the planar layout of the power module provided in an embodiment of the present invention;

[0029] Figure 2 A partial cross-sectional view of the power module provided in an embodiment of the present invention;

[0030] Figure 3 A schematic diagram of the equivalent circuit of the power module provided in an embodiment of the present invention;

[0031] Figure 4 This is a schematic diagram of the equivalent circuit of a power chipset provided in an embodiment of the present invention;

[0032] Figure 5 A partial cross-sectional view of a power module provided in an embodiment of the present invention. Detailed Implementation

[0033] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0034] Automotive-grade power modules typically employ half-bridge circuits. Currently, the vast majority of power modules are wirebonded using aluminum and copper wires. This method results in relatively high resistance and parasitic inductance. High resistance reduces the power module's conversion efficiency, while high inductance affects its turn-on and turn-off performance, and may even cause overvoltage damage to the chip. Although using copper clip (conductive sheet) packaging can reduce parasitic inductance, it faces the following technical challenges:

[0035] (1) The connection between each conductive sheet and the circuit conductor is located on one side of the chip, presenting a "point". The current from the top of multiple chips flows to one end of the conductive sheet. The parasitic inductance of each chip is inconsistent, and the current of some chips is too large, resulting in a large temperature difference between each chip.

[0036] (2) The contact area between the conductive sheet and the circuit conductor is small, and the conductive sheet is prone to drift during welding, which makes the welding process difficult and prone to false welding; and the reliability of the welding layer is also poor under high temperature and high current density.

[0037] Figure 1 This is a plan view of the power module provided in this embodiment. Figure 2 yes Figure 1 The cross-sectional view of the area within the dashed box. Please refer to it as well. Figure 1 and Figure 2 The power module provided by the present invention will now be described.

[0038] The power module includes a substrate 10 and multiple power chips 11.

[0039] Multiple power chips 11 are divided into multiple power chip groups. One side surface of the substrate 10 has multiple first circuit conductors 12 that correspond one-to-one with the power chip groups. The power chip groups are located on the corresponding first circuit conductors 12. The power chips 11 in the power chip groups are all arranged along a first direction, and the input terminals of the power chips 11 in the power chip groups are all connected to the corresponding first circuit conductors 12.

[0040] The substrate 10 also has a second circuit conductor 13 corresponding to each power chip group on this side surface. The second circuit conductor 13 is located on any side of the corresponding power chip group column direction. Each power chip group also corresponds to a conductive sheet 14. The output terminal of the power chip 11 in each power chip group is connected to the second circuit conductor 13 corresponding to the power chip group through the conductive sheet 14 corresponding to the power chip group.

[0041] The substrate 10 is also provided with DC terminals 15, 16, 17 and AC terminals 18 on this side surface. The first circuit conductor 12 and the second circuit conductor 13 are also connected to the DC terminals or AC terminals to form a half-bridge topology.

[0042] In this embodiment, with Figure 1 For example, the diagram includes four power chipsets, each containing four power chips 11. All power chipsets are arranged in the same direction, but the first direction can be any direction. Figure 1 In this configuration, 16 can be the positive (P) terminal of the DC circuit, and 15 and 17 can be the negative (N) terminals of the DC circuit. Alternatively, 16 can be the negative terminal of the DC circuit, and 15 and 17 can be the positive terminals of the DC circuit. The various power chipsets, DC terminals, and AC terminals are connected to form a half-bridge topology.

[0043] As one possible implementation, when 16 is the positive terminal of the DC terminal and 15 and 17 are the negative terminals of the DC terminal:

[0044] A portion of the first circuit conductor is connected to the DC positive terminal 16, and the second circuit conductor 13 connected to the power chip group corresponding to the first circuit conductor 12 connected to the DC positive terminal 16 is connected to the AC terminal 18.

[0045] Another part of the first circuit conductor is connected to the AC terminal 18, and the second circuit conductor 13 of the power chip group corresponding to the first circuit conductor connected to the AC terminal 18 is connected to the DC negative terminal 15 and 17 respectively.

[0046] That is, located in Figure 1 The power chip sets on the two middle second circuit conductors 12 are first connected to the corresponding second circuit conductors 13 via conductive plates 14, and then the second circuit conductors 13 are connected to the AC terminal 18. Figure 1 The power chip groups on the two second circuit conductors 12 on both sides are first connected to the corresponding second circuit conductors 13 through conductive sheets 14, and then the two second circuit conductors 13 are connected to 15 and 17 respectively.

[0047] In this embodiment, eight power chips from the two middle power chip groups are connected in parallel to form the upper switch G1 of the power module, and eight power chips from the two side power chip groups are connected in parallel to form the lower switch G2 of the power module. The upper switch G1 and the lower switch G2 are connected in series. The equivalent circuit can be found in [reference needed]. Figure 3 As shown. When the power module is working, the current from the DC bus passes through the DC positive terminal, DC negative terminal, circuit conductors, input electrode of the power chip, output electrode of the power chip, conductive plate, and AC terminal, and is output to the load.

[0048] Generally, for higher power modules, the upper and lower switches are usually composed of multiple MOSFETs or IGBTs or other power semiconductor chips connected in parallel.

[0049] By changing the soldering points between the conductive sheet and the second circuit conductor to the left and right sides of the power chip, the parasitic inductance of the power chip is consistent, resulting in better current sharing, smaller temperature difference of the power chip, and less susceptibility to damage.

[0050] Furthermore, the increased contact area between the conductive sheet and the second circuit conductor makes it less prone to drifting during welding, significantly reducing the difficulty of the welding process, increasing yield, and lowering costs. Simultaneously, the increased contact area at the welding point between the conductive sheet and the second circuit conductor reduces current density and increases the reliability of the welding point at high temperatures.

[0051] In addition, this packaging method can increase the area of ​​the conductive sheet, making the area of ​​the conductive sheet approximately the same as that of the corresponding first circuit conductor. If double-sided heat dissipation is used, the thermal resistance of the upper and lower thermal paths of the module is approximately the same, the surface temperature of the upper and lower surfaces of the power module is approximately the same, the thermal stress of the upper and lower parts of the module is more symmetrical, and the reliability is improved.

[0052] by Figure 1Taking a group of power chips M1-M4 as an example, the equivalent circuit is as follows: Figure 5 For four power chips, the impedances of their conducting loops are approximately the same. For example, for the first and last power chips, the impedance of power chip M1 is Z1 = L8 + L1 + L2 + L3 + L4, and the impedance of power chip M4 is Z4 = L4 + L5 + L6 + L7 + L8. Since the areas of the conductive plates and the corresponding conductors in the first circuit are approximately the same, L1≈L7, L2≈L6, L3≈L5, so Z1≈Z4. Because the impedances are close, the parallel circuit exhibits better dynamic and static current sharing characteristics under the same voltage.

[0053] As one possible implementation, when 16 is the negative terminal of the DC terminal and 15 and 17 are the positive terminals of the DC terminal, a portion of the first circuit conductor is connected to the negative DC terminal, and the second circuit conductor connected to the power chip group corresponding to the first circuit conductor connected to the negative DC terminal is connected to the AC terminal; another portion of the first circuit conductor is connected to the AC terminal, and the second circuit conductor connected to the power chip group corresponding to the first circuit conductor connected to the AC terminal is connected to the positive DC terminal. That is, in this embodiment, the positions of the upper and lower switches are interchanged, and the effect is similar to that of the above embodiment, so it will not be described in detail again.

[0054] As one possible implementation, see Figure 1 As shown, the first circuit conductor 12 and the conductive sheet 14 are both rectangular structures. The two opposite sides of the rectangle that are parallel to the first direction are the long sides, and the two opposite sides of the rectangle that are perpendicular to the first direction are the wide sides. The width ratio of the wide side L1 of the first circuit conductor 12 to the wide side L2 of the corresponding conductive sheet 14 is between 0.6 and 1.5.

[0055] In this embodiment, the width ratio of the wide side L1 of the first circuit conductor 12 to the wide side L2 of the corresponding conductive sheet 14 is set within a certain range, and the long side of the first circuit conductor 12 and the long side of the corresponding conductive sheet 14 are also set as close as possible, so that the areas of the first circuit conductor 12 and the conductive sheet 14 are close, and the dynamic and static current sharing characteristics of the parallel circuit can be improved under the same voltage.

[0056] Alternatively, the ratio of the area of ​​the first circuit conductor 12 to the area of ​​the conductive sheet 14 is between 0.6 and 1.5.

[0057] In one embodiment, 16 is the negative terminal of the DC terminal, and 15 and 17 are the positive terminals of the DC terminal, as an example:

[0058] See Figure 1 As shown, the number of first circuit conductors 12 connected to the DC positive terminal 16 is equal to the number of first circuit conductors 12 connected to the AC terminal 18. The number of power chips 11 in each power chip group is the same, and the distance between any two adjacent power chips 11 in each power chip group is the same.

[0059] In this embodiment, the upper switch G1 (the two middle power chip groups) and the lower switch G2 (the two power chip groups on both sides) contain the same number of power chip groups, and each power chip group contains the same number of power chips 11, thereby forming a highly symmetrical half-bridge module with better current sharing. This application does not impose specific limitations on the number of power chip groups and power chips, and can set them according to actual needs.

[0060] Furthermore, the power chip 11 in the power chip group corresponding to the first circuit conductor 12 connected to the DC positive terminal 16 is of the first type, and the power chip 11 in the power chip group corresponding to the first circuit conductor 12 connected to the AC terminal 18 is of the second type; the first type and the second type may be the same or different.

[0061] Optionally, the first type and the second type are diodes or metal-oxide-semiconductor field-effect transistors.

[0062] In this embodiment, the power chip types in the upper switch G1 and the lower switch G2 are generally the same, achieving a high degree of symmetry. When the power chip types in the upper switch G1 and the lower switch G2 are different, they can form a chopper circuit or a boost circuit that commutates with each other. Typically, one is a diode and the other is a MOSFET (Metal Oxide Semiconductor Field Effect Transistor).

[0063] As one possible implementation, the connection position between the second circuit conductor 13 and the conductive sheet 14 adopts a semi-etched structure.

[0064] In this embodiment, see Figure 5 As shown, the second circuit conductor 13 is improved to a semi-etched structure, which can further increase the soldering yield and reliability.

[0065] As one possible implementation, the connection between the power chip 11 and the conductive sheet 14, and between the power chip 11 and the first circuit conductor 12, can be any one of the following: conductive adhesive film, silver paste, silver or copper sintering, semi-sintering, brazing / solder ball / solder sheet soldering, transient liquid phase welding, anisotropic connection, ultrasonic welding, and laser welding. Wirebonding technology is generally not applicable.

[0066] As one possible implementation, the conductive sheet 14 can be a copper alloy or other conductive material.

[0067] As one possible implementation, the gate of power chip 11 can also be soldered using a conductive sheet and can be connected to a gate resistor. The power module is not limited to single-sided or double-sided heat dissipation power modules. The first circuit conductor and the second circuit conductor can be DBC, AMB, leadframe, or conductive layers on the PCB.

[0068] Based on the above embodiments, the beneficial effects of the present invention can be summarized as follows:

[0069] (1) The power chip has low resistance and consistent parasitic inductance, resulting in better current sharing and making the chip less prone to damage.

[0070] (2) The difficulty of the conductive sheet welding process has been greatly reduced, the yield rate has increased, and the cost has decreased;

[0071] (3) The current density at the contact surface of the solder joint between the conductive sheet and the circuit conductor decreases, and the reliability increases;

[0072] (4) When used for double-sided heat dissipation, the thermal resistance of the upper and lower thermal paths of the power module is approximately the same, and the thermal stress of the upper and lower parts of the power module is more symmetrical, thereby significantly improving the reliability of the power module.

[0073] This invention provides a vehicle in which each system circuit uses the power module described above for power conversion.

[0074] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A power module, characterized in that, include: Substrate and multiple power chips; The plurality of power chips are divided into a plurality of power chip groups. One side surface of the substrate has a plurality of first circuit conductors corresponding one-to-one with the power chip groups. The power chip groups are located on the corresponding first circuit conductors. The power chips in the power chip groups are arranged along a first direction, and the input terminals of the power chips in the power chip groups are all connected to the corresponding first circuit conductors. The substrate also has a second circuit conductor on this side surface that corresponds to the power chip group. The second circuit conductor is located on any side of the corresponding power chip group column direction. Each power chip group also corresponds to a conductive sheet. The output terminal of the power chip in each power chip group is connected to the second circuit conductor corresponding to the power chip group through the conductive sheet corresponding to the power chip group. The substrate is further provided with a DC terminal and an AC terminal on this side surface, and the first circuit conductor and the second circuit conductor are also connected to the DC terminal or the AC terminal to form a half-bridge topology. The DC terminal includes: a positive DC terminal and a negative DC terminal; A portion of the first circuit conductor is connected to the DC positive terminal, and the second circuit conductor connected to the power chip group corresponding to the first circuit conductor connected to the DC positive terminal is connected to the AC terminal; another portion of the first circuit conductor is connected to the AC terminal, and the second circuit conductor connected to the power chip group corresponding to the first circuit conductor connected to the AC terminal is connected to the DC negative terminal. Alternatively, a portion of the first circuit conductor is connected to the DC negative terminal, and the second circuit conductor connected to the power chip group corresponding to the first circuit conductor connected to the DC negative terminal is connected to the AC terminal; another portion of the first circuit conductor is connected to the AC terminal, and the second circuit conductor connected to the power chip group corresponding to the first circuit conductor connected to the AC terminal is connected to the DC positive terminal.

2. The power module as described in claim 1, characterized in that, The first circuit conductor and the conductive sheet are both rectangular structures, with the two opposite sides of the rectangle parallel to the first direction being the long side and the two opposite sides of the rectangle perpendicular to the first direction being the short side; The width ratio of the wider side of the first circuit conductor to the wider side of the corresponding conductive sheet is between 0.6 and 1.

5.

3. The power module as described in claim 1, characterized in that, The number of first circuit conductors connected to the DC positive terminal is equal to the number of first circuit conductors connected to the AC terminal.

4. The power module as described in claim 3, characterized in that, Each power chipset contains the same number of power chips, and the distance between any two adjacent power chips in each power chipset is the same.

5. The power module as described in claim 4, characterized in that, The power chip in the power chip group corresponding to the first circuit conductor connected to the DC positive terminal is of the first type, and the power chip in the power chip group corresponding to the first circuit conductor connected to the AC terminal is of the second type. The first type and the second type may be the same or different.

6. The power module as described in claim 5, characterized in that, The first type and the second type are diodes or metal-oxide-semiconductor field-effect transistors.

7. The power module as described in claim 1, characterized in that, The connection point between the second circuit conductor and the conductive sheet adopts a semi-etched structure.

8. A vehicle, characterized in that, Each system circuit in the vehicle uses a power module as described in any one of claims 1-7 for power conversion.

Images