Embedded PCB Busbars for High-Current Load Switching Heat Control
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Solution Overview
Problem
Traditional load switching units for battery packs in electric vehicles require significant space due to mechanical contactors and face high discharge and short circuit currents, necessitating improved solutions for efficient current handling and heat management.
Innovation Solution
A printed circuit board (PCB) with embedded busbars functions as both a heat sink and current conductor, eliminating feedthrough connections and reducing inductance, allowing for improved heat transfer and current carrying capacity, particularly through the use of copper busbars and semiconductor switches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If mechanical contactors are used for load switching, then reliable current handling is achieved, but device space occupation increases significantly
Solution Approach 1:
The patent replaces mechanical contactors with semiconductor switches (MOSFETs or IGBTs) mounted on a PCB. This substitution eliminates the need for large mechanical moving parts while maintaining reliable current switching capability through electronic control, directly resolving the contradiction between reliability and space occupation.
Solution Approach 2:
The PCB serves multiple functions simultaneously: it acts as the circuit board for mounting semiconductor switches, provides embedded busbars for current conduction, and functions as a heat sink for thermal management. This multi-functionality consolidates what would traditionally require separate components into a single integrated structure, reducing overall device space.
2Reliability
If feedthrough connections are used to couple switches to busbar, then electrical connection is established, but heat transfer interfaces increase and inductance rises
Solution Approach 1:
The patent merges the electrical connection function and thermal management function into a single integrated structure. The semiconductor switches are directly mounted on the PCB body which contains embedded busbars, eliminating the need for separate feedthrough connections. This direct coupling reduces the number of heat transfer interfaces and minimizes inductance, thereby reducing energy loss.
Solution Approach 2:
The invention extracts the feedthrough connection layer from the system by implementing direct mounting of switches to the PCB body with embedded busbars. This removal of the intermediate feedthrough layer eliminates the additional heat transfer interface and associated inductance that would otherwise be present in traditional designs.
3Reliability
If multiple heat transfer interfaces are used in switch-to-busbar connection, then electrical connection is achieved, but heat transfer efficiency decreases
Solution Approach 1:
The patent combines the electrical connection path and thermal conduction path into a single integrated structure. The PCB body with embedded busbars provides direct thermal coupling between the semiconductor switches and the heat dissipation path, eliminating multiple heat transfer interfaces and improving overall heat transfer efficiency.
4Ease of manufacture
If traditional PCB design without embedded busbars is used, then manufacturing is simpler, but current carrying capacity is insufficient for high current applications
Solution Approach 1:
The patent employs composite material construction where copper busbars are embedded within the PCB body matrix. This composite structure combines the electrical and thermal conductivity of copper with the structural and insulating properties of the PCB material, achieving both high current carrying capacity and manufacturability through established PCB fabrication techniques.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The PCB design enhances current handling capabilities, supports high currents up to 1000 amperes, improves manufacturing efficiency, and ensures reliable operation under transient loads by minimizing heat transfer interfaces and inductance.
Implementation Method 1
The PCB also comprises a busbar embedded into the PCB body for acting as a heat sink, which allows heat generated from load switching to be transferred across the PCB body
Implementation Method 2
The busbar therefore does not simply function as a heat sink but also as a current conductor for the load switching, e.g. from a battery pack via the busbar to a dc link of an electric vehicle
Implementation Method 3
Since the busbar is embedded into the PCB body, the switch(es) can be coupled to the busbar without feedthrough connections. This, in turn, allows improving the heat transfer coefficient between the switch(es) and the busbar
Implementation Method 4
Feedthrough connections through the PCB body would cause such additional inductances, which can be avoided with the embedded busbar
Data Source
AI summary
Disclosed is a printed circuit board (PCB) for load switching between an electric power supply and one or more loads. The PCB comprises a PCB body, a busbar embedded into the PCB body for acting as a heat sink and one or more switches for the load switching, wherein the one or more switches are coupled to the busbar for routing an electric current for the load switching through the busbar.