Pyrotechnic Rivet Busbar Connection for Battery Thermal Disconnect
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Solution Overview
Problem
Existing electrical connection systems in traction battery packs lack efficient thermal management and fail to safely disconnect electrical connections during high thermal events, potentially leading to circuit failures and safety hazards.
Innovation Solution
A pyrotechnic rivet-based electrical connection system that connects busbars between battery terminals across different cell stacks, where the rivet ruptures upon exceeding a thermal energy threshold, decoupling the electrical contacts and ensuring safe disconnection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional electrical connection systems are used to connect busbars between battery terminals, then electrical connectivity is maintained, but thermal management is insufficient and circuit failures may occur during high thermal events
Solution Approach 1:
The rivet connection system transitions from a static permanent connection to a dynamic conditional connection. The rivet remains intact under normal operating conditions but automatically ruptures when thermal energy exceeds the threshold, allowing the electrical connection to adapt its state based on thermal conditions. This dynamic behavior resolves the contradiction by maintaining reliability through automatic disconnection during thermal events while preserving connectivity during normal operation.
Solution Approach 2:
The system utilizes parameter changes in the rivet material properties, specifically its thermal response characteristics. The rivet is designed with specific melting point or structural transition parameters that change at critical thermal thresholds, causing it to rupture and disconnect the circuit. This parameter-based approach allows the connection system to respond to thermal stress by changing its structural state, thereby improving safety during thermal events while maintaining normal electrical connectivity.
2Reliability
If permanent electrical connections are used between busbars, then electrical connectivity is ensured, but the ability to safely disconnect during thermal events is lost
Solution Approach 1:
The rivet-based connection system performs self-service by automatically detecting thermal conditions and executing disconnection without external intervention. The rivet itself serves as both the mechanical fastener and the thermal sensor, using its own material properties to detect excessive heat and initiate rupture. This self-service mechanism provides safe disconnection capability while avoiding the need for additional sensors, control systems, or external actuation mechanisms, thereby limiting the increase in device complexity.
3Reliability
If rivets are used to connect electrical contacts, then thermal stress management is improved through controlled rupture, but manufacturing precision requirements increase
Solution Approach 1:
The connection system is segmented into distinct functional components: the rivet shaft for mechanical connection, the rivet body for structural integrity, and the pyrotechnic charge for controlled rupture. This segmentation allows each component to be optimized and manufactured independently with specific precision requirements, rather than requiring the entire connection system to meet uniform high precision standards. The modular nature of segmented components facilitates easier manufacturing and assembly while maintaining reliable thermal stress management functionality.
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 system effectively manages thermal stress by safely disconnecting electrical connections, preventing circuit failures and enhancing the safety and reliability of traction battery packs during high thermal events.
Implementation Method 1
the at least one rivet is configured to rupture in response to a thermal energy level exceeding a threshold
Implementation Method 2
a spring sandwiched between the first electrical contact and the second electrical contact, the spring biasing the first electrical contact away from the second electrical contact
Data Source
AI summary
An electrical connection system for a traction battery pack includes a first electrical contact, a second electrical contact, and at least one rivet that connects the first electrical contact directly to the second electrical contact. A method of electrically connecting components within a traction battery pack includes aligning a first aperture within a first electrical contact relative to a second aperture within a second electrical contact, and electrically connecting the first electrical contact to the second electrical contact using a rivet having a shaft that extends through both the first aperture and the second aperture. The rivets can be pyrotechnic rivets.