Multi-Switch Contactor Assembly With Integrated Pre-Charge Relay
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Solution Overview
Problem
Electromechanical switching devices in electric vehicles face challenges in preventing short circuits and mechanical shock, particularly when switching between battery packs, as existing solutions require constant power to maintain switch states and can lead to safety hazards and device damage.
Innovation Solution
A multi-switch contactor assembly with a single mechanical actuation mechanism that uses cams coupled to a shaft to operate multiple switches, preventing dangerous combinations and leveraging Lorentz forces for increased contact force, eliminating the need for a separate pre-charge circuit and reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple electromechanical switches are used to control battery pack connections, then the battery configuration can be changed, but the risk of short circuits and mechanical shock increases
Solution Approach 1:
Multiple switches are mechanically coupled to a single actuator mechanism, ensuring coordinated operation. The cam shaft integrates the actuation of multiple switches into one unified mechanical system, preventing unsafe switch combinations through mechanical interdependence rather than electronic control.
Solution Approach 2:
A pre-charge relay with resistor is introduced as an intermediary component between the battery pack and the main circuit. This relay activates first to pre-charge the circuit, preventing inrush current and short circuits during the switching process, before the main battery connection switches close.
2Stability of the object's composition
If constant power is supplied to maintain switch states, then the switches remain stable, but energy consumption increases
Solution Approach 1:
The mechanical cam-based actuation mechanism uses the motion of the actuator itself to open and close switches without requiring external power during the switching action. The cam profiles mechanically force the switches into desired positions, eliminating the need for powered hold circuits.
Solution Approach 2:
The patent replaces electrically-powered switch holding mechanisms with a purely mechanical cam-based system. The cam shaft and cam profiles create physical constraints that determine switch states through mechanical geometry rather than electromagnetic forces, eliminating continuous power requirements.
3Reliability
If separate pre-charge circuit is used, then pre-charge function is achieved, but device complexity increases
Solution Approach 1:
The pre-charge relay is mechanically integrated with the main battery connection switches through the same cam shaft actuation system. This mechanical coupling ensures the pre-charge relay activates in the correct sequence before the main switches close, achieving pre-charge functionality while reducing overall system complexity through unified mechanical control.
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 solution ensures safe and reliable switching by preventing short circuits, maintaining high contact force with low resistance, and eliminating the need for continuous power, enhancing the safety and efficiency of electric vehicle power distribution systems.
Implementation Method 1
In the presence of high current through the fixed contact and the moveable contact, Lorentz forces acting on the moveable contact repel the moveable contact toward the fixed contact, thus increasing the contact force
Data Source
AI summary
In an embodiment, a multi-switch contactor assembly with a pre-charge system is disclosed. The multi-switch contactor further includes an array of switches and an actuator assembly configured to actuate each switch of the array of switches. In this embodiment, the array of switches includes a first switch configured to connect a first battery device to a circuit and a second switch configured to connect a second battery device to the circuit. The array of switches also includes a third switch configured to connect the first battery device and the second battery device in series to the circuit and a fourth switch configured to connect a pre-charge resistor to at least one of the first battery device and the second battery device.