Floating Service Plug Terminals for EV Battery Sealing
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Solution Overview
Problem
Existing battery systems for electric vehicles face challenges in maintaining a reliable electrical connection and water-tight configuration, particularly with the service plug, which can lead to increased contact resistance and reduced efficiency due to misalignment and shifting of connecting terminals and receptacles.
Innovation Solution
The battery system incorporates a service plug with a floating configuration for its connecting terminals, allowing movement perpendicular to the insertion direction, and a gasket sandwiched between the plug case and external case for a water-tight connection, ensuring proper alignment and reduced contact resistance through a cylindrical region and projecting region design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the service plug is connected in a fixed position with a gasket for water-tight configuration, then water-tight sealing is improved, but the connecting terminals may shift relative to receptacles causing increased contact resistance
Solution Approach 1:
The connecting terminals are designed with a floating configuration that allows dynamic adjustment of their positions. The terminals can move perpendicular to the insertion direction to compensate for misalignment between the service plug and external case, while the gasket maintains the water-tight seal. This dynamic adaptability resolves the contradiction between fixed positioning for sealing and alignment precision for electrical connection.
2Reliability
If the connecting terminals are made thick with low electrical resistance, then contact resistance is reduced, but the terminals cannot be inserted in proper position when position error occurs
Solution Approach 1:
The connecting terminals are designed to be movable rather than fixed, allowing them to self-adjust to the correct insertion position even when position errors occur during assembly. This dynamic capability provides position tolerance while maintaining good electrical connection quality, resolving the contradiction between connection quality and position adaptability.
3Object-affected harmful factors
If the service plug is removed to cut-off output power for safety during maintenance, then safety is improved, but the electrical connection reliability may degrade due to repeated connection and disconnection
Solution Approach 1:
The floating configuration of the connecting terminals provides a cushioning effect that absorbs the mechanical stress and position misalignment caused by repeated connection and disconnection operations. This protects the electrical connection from degradation while allowing the service plug to be removed for safety during maintenance.
Data Source
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AI summary
The service plug 4 has a plug case 40 housing a fuse 5 provided with a pair of connecting terminals 51. The external case 2 is provided with a plug connecting section 25 for connection of the plug case 40, and receptacles 31 for connection of the connecting terminals 51. The fuse 5 connects to the batteries 1 through the connecting terminals 51 and receptacles 31 to output voltage across the output terminals 7. In addition, a gasket 49 is provided between the plug case 40 and the plug connecting section 25 to connect the service plug 4 to the external case 2 in a water-tight manner. Further, the connecting terminals 51 are held in the plug case 40 in a mechanically floating configuration that allows movement at right angles to the direction of insertion.