Power Modules with Solderless Terminals

Abstract

The present invention relates to a power module of a welding-free terminal. The terminal comprises a connection part with an elastic upper part and a main body part with a shaft shoulder, and the bottom surface of the terminal is toothed. Plugholes for guiding the main body parts of various terminals are provided on a housing, and sunken platforms corresponding to the shaft shoulders of the terminals are arranged at the tops of the plugholes; the terminals are arranged in the respective corresponding plugholes of the housing; the shaft shoulders of the terminals are arranged on the sunken platforms; an elastic insulating pressure pad is arranged at the upper part of the housing; a cover plate is mounted onto the housing by a clamped connection and is in a pressure connection on the elastic insulating pressure pad; the terminals penetrate through respective corresponding terminal holes on the elastic insulating pressure pad and respective corresponding terminal holes on the cover plate; the elastic insulating pressure pad presses on the shaft shoulders of the terminals; the toothed bottom surfaces at the bottom of the terminals are in a pressure connection on a cermet coated substrate; and the connection parts of the terminals are elastically connected with terminal holes of a driver circuit board. The present invention is reasonable in structure; and the terminals do not need to be welded and can be reliably connected to a cermet coated substrate after being assembled, and the manufacturability is good.

Description

technical field [0001] The invention relates to a power module without welding terminals, belonging to the technical field of power module manufacturing. Background technique [0002] Power modules are widely used in AC motor frequency conversion speed regulation and DC motor chopper speed regulation and various high-performance power supplies, such as UPS, induction heating, electric welding machines, active compensation, DC-DC, etc., as well as industrial electrical automation and other fields. market. Traditional power semiconductor modules mainly include housing, main circuit board and drive circuit board, MOSFET or IGBT chips and diode chips are integrated and welded or pasted on the metal layer of the metal-ceramic substrate, while electrode terminals and signal terminals are also welded The cermet-covered substrate constitutes the main circuit board, and the printed circuit board welded with integrated circuit chips and various devices constitutes the drive circuit b...

AI Technical Summary

Problems solved by technology

[0003] During the installation process, the main circuit board with the terminals welded on it needs to be installed on the shell, and the cover plate is installed on the shell, and each terminal passes through the terminal hole on the cover plate. The gap between the hole and the terminal is small, but because the shell is usually made of insulating plastic injection molding, the wall thickness of the shell is inconsistent, which will cause deformation of the cover plate after installation, which will affect the installation efficiency and assembly quality of each terminal

Furthermore, because the terminals need to pass through the terminal holes on the drive circuit board, and the upper part of the terminals are needle-shaped or plate-shaped structures, especially the needle-shaped terminals are not strong enough, it is easy to cause the terminals to be damaged during the installation process. Deformation occurs after external force, even during the welding process. When the terminal deformation is too large, it will fail, which not only affects the assembly efficiency and installation quality, but also affects the service life of the semiconductor module

In addition, all existing terminals are welded on the drive circuit board, which makes it inconvenient to maintain the power module

[0004] In addition, most of the terminals on the current power module are sintered on the metal layer of the metal-ceramic substrate by solder at high temperature. During the welding process, the metal layer and the terminal of the metal-ceramic substrate will generate welding stress at the solder layer at high temperature. The working environment of the power module is cycled at -40°C to 125°C, so after a period of work, it will eventually cause the connection between the metal layer of the metal ceramic substrate and the signal terminal to fall off, resulting in welding fatigue, which affects the Overall Power Device Lifetime

Secondly, the signal terminals are welded on the metal layer of the cermet-clad substrate through the connection surface, which not only has high requirements on the surface of the metal layer of the cermet-clad substrate and the surface of the signal terminal, especially the metal layer of the cermet-clad substrate, that is, the copper foil and the signal terminal. There is also a difference in thermal expansion between the copper materials, and the welding performance is not high, which affects its electrical conductivity. At the same time, the welding process not only requires solder, flux and protective gas during welding. Not only does the high-temperature sintering welding process take a long time, but all The high temperature generated can easily lead to the weakening of the metal properties of other parts of the material. In addition, factors such as solder flow and solder resist ink during the welding process will cause the risk of contamination on the welding surface. There are difficulties in controlling the welding surface, complicated process operations, and low welding efficiency low problem

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