Bridge Power Module Structure for High Current Across Split Substrates
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Solution Overview
Problem
Existing power modules for electric vehicles face challenges in handling high currents due to thin wires used for connection between main substrates, which can lead to damage from thermal stress, and using large-area metal plates introduces higher thermal expansion coefficients that further risk damage.
Innovation Solution
The power module incorporates a bridge main unit comprising multiple bridge subunits that connect the first and second power input terminals, switches, and substrates, allowing for the transmission of current, control, and output signals across the substrates while mitigating thermal stress through the use of substrates with low thermal expansion coefficients.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If thin wires are used to connect main substrates, then the device complexity is reduced, but the current bearing capacity deteriorates
Solution Approach 1:
The patent merges the connection functions of power transmission and control signal transmission into a single integrated metal plate structure. The metal plate simultaneously serves as the power transmission path between main substrates and as the connection medium for control signals, eliminating the need for separate wire connections and thereby resolving the contradiction between structural simplicity and current bearing capacity.
2Reliability
If large-area metal plate is used instead of wire, then the current bearing capacity is improved, but the thermal expansion compatibility deteriorates
Solution Approach 1:
The patent employs a composite material structure where the metal plate is integrated with the main substrates through low thermal expansion coefficient materials or thermal expansion compensation structures. This composite approach allows the metal plate to bear high currents while the integrated structure compensates for thermal expansion differences, preventing damage during temperature cycles and resolving the contradiction between current capacity and thermal stability.
3Device complexity
If single main substrate is used for switch circuit, then the device complexity is reduced, but the thermal stress resistance deteriorates
Solution Approach 1:
The patent segments the switch circuit into multiple main substrates that are connected through the metal plate. This segmentation allows each substrate to be optimized for specific functions while the metal plate provides robust power transmission and thermal management. The distributed substrate structure enhances thermal stress resistance by distributing thermal loads across multiple components, resolving the contradiction between structural simplicity and thermal reliability.
Data Source
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AI summary
A power module (1) includes two power input terminals (10 and 20), two main substrates (30 and 40), a plurality of first switches (50), a plurality of second switches (60), and a bridge main unit (70). The bridge main unit (70) is across the two main substrates (30 and 40), and includes a first bridge subunit (71) and a second bridge subunit (72). Each of the first bridge subunit (71) and the second bridge subunit (72) includes a first conducting region (CA1) on a bottom surface (SF3), and a second conducting region (CA2) and a third conducting region (CA3) on a top surface (SF4). The first conducting region (CA1) transmits a current signal of a current path (AA) of a switch circuit (80) formed by the power input terminals (10 and 20), the first switches (50), and the second switches (60). The second conducting region (CA2) is connected to the control terminals (G1 and G2) of the first switches (50) and the second switches (60). The third conducting region (CA3) is connected to the output terminals (S1 an S2) of the first switches (50) and the second switches (60).