Battery Pack Relay Sequencing to Suppress Siloxane Contact Failure
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Solution Overview
Problem
Relay contact failures due to siloxane-derived insulators are prevalent in battery packs, particularly in sealed environments, leading to increased costs and potential contact failures even with sealed relays.
Innovation Solution
A relay control device controls the operation of a relay circuit with a specific sequence of turning on and off relays, including a pre-charge relay, a first main relay, and a second main relay, to minimize the generation of siloxane-derived insulators by avoiding electric arcs during connection and disconnection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sealed relays are used to prevent contact failures, then reliability is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts and removes the harmful siloxane-derived insulator deposits from the relay contact surface through a cleaning mechanism, eliminating the need for sealed relay structures while maintaining contact reliability
Solution Approach 2:
The patent replaces the mechanical sealing approach with an electrical cleaning mechanism that uses controlled electrical discharge to remove insulator deposits from contact surfaces, substituting a complex sealing structure with a simpler active cleaning system
2Object-affected harmful factors
If relays operate in sealed battery pack environments, then protection from external contaminants is improved, but siloxane-derived insulator generation increases leading to contact failures
Solution Approach 1:
The patent converts the harmful effect of siloxane vapor accumulation in sealed environments into a beneficial cleaning mechanism, where controlled electrical discharge generates plasma that actively removes insulator deposits, transforming the sealed environment's drawback into a self-cleaning advantage
Solution Approach 2:
The patent utilizes plasma-generated oxidative reactions to rapidly decompose and remove siloxane-derived insulator deposits from contact surfaces, employing strong oxidizing conditions to eliminate the harmful deposits that form in sealed environments
3Reliability
If relay contacts are sealed to prevent insulator adhesion, then contact reliability is improved, but manufacturing cost increases
Solution Approach 1:
The patent employs a cost-effective electrical cleaning mechanism that periodically restores contact surface conductivity, replacing expensive sealed relay components with a simpler, maintainable system that uses inexpensive electrical discharge to remove insulator deposits
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
Effectively suppresses relay contact failures by breaking and removing siloxane-derived insulators without the need for sealed relays, thereby reducing costs and maintaining reliable connections.
Implementation Method 1
minimize the generation of siloxane-derived insulators by avoiding electric arcs during connection and disconnection
Data Source
AI summary
A relay control device controls an operation of a relay circuit, which is disposed between a battery and an electric load, and the relay circuit is sealed in a case of a battery pack. The relay circuit includes: a first main relay disposed in a first conduction path which is connected to a first terminal of the battery; a second main relay disposed in a second conduction path which is connected to a second terminal of the battery; and a pre-charge relay connected to the second conduction path in parallel with the second main relay. The relay control device turns on the pre-charge relay, the first main relay, and the second main relay in order, and then turns off the pre-charge relay, the first main relay, and the second main relay in order.