Battery Pack Interconnectors Using Wire Bonds and Fuses
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Solution Overview
Problem
Existing battery pack connection methods, particularly resistive spot welding, are time-consuming, prone to failure, and pose safety risks due to thermal imbalances and short circuits, lacking electrical protection and quality control.
Innovation Solution
An interconnector system using wire bonding with a main interconnect segment, wire bonds, and optional signal output and busbar segments, featuring electric fuses to prevent overcurrent and provide real-time monitoring, made of metals like copper and nickel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If resistive spot welding is used to join cells, then low manufacturing cost is achieved, but connection reliability and safety deteriorate due to thermal imbalances and short circuits
Solution Approach 1:
The patent replaces the mechanical resistive spot welding system with an ultrasonic wire bonding system. The ultrasonic wire bonding process uses high-frequency vibrations to create metallurgical bonds between wires and cell terminals, eliminating the thermal processes inherent in spot welding. This substitution provides reliable electrical connections without the thermal imbalances and short circuit risks associated with resistive spot welding, while maintaining manufacturing efficiency through automated bonding processes.
2Ease of manufacture
If resistive spot welding is used to join cells, then low manufacturing cost is achieved, but manufacturing time increases due to quality checking difficulties
Solution Approach 1:
The ultrasonic wire bonding system replaces spot welding with a process that inherently provides better quality control. The bonding process parameters (ultrasonic power, bonding time, force) can be precisely controlled and monitored, ensuring consistent bond quality. The wire bonds create visible, accessible connection points that are easier to inspect than spot welds, enabling faster quality assurance without sacrificing manufacturing speed.
Solution Approach 2:
The wire bonding process creates self-evident connection quality through the visible bond formation and electrical continuity. The process parameters automatically record bonding characteristics, providing built-in quality metrics that reduce the need for separate inspection steps and accelerate manufacturing throughput.
3Volume of moving object
If cells are closely packed in a battery pack, then space efficiency is improved, but thermal management deteriorates due to heat propagation from shorted cells
Solution Approach 1:
The patent introduces wire bonds as intermediary connection elements between cells, replacing direct metal-to-metal contact through spot welding. These wire bonds act as thermal and electrical intermediaries that can be designed with appropriate current-carrying capacities and thermal characteristics. The wire bonds provide electrical connectivity while managing heat distribution, preventing localized hot spots and reducing the risk of thermal runaway propagation between closely packed cells.
4Device complexity
If manual spot welding is used to join cells, then equipment complexity is reduced, but manufacturing precision deteriorates due to quality variation
Solution Approach 1:
The ultrasonic wire bonding system replaces manual spot welding with an automated process that uses controlled ultrasonic vibrations to create consistent metallurgical bonds. The process parameters (frequency, power, duration, force) are precisely controlled by computer systems, ensuring uniform bond quality across all connections. This automation eliminates the human variability inherent in manual operations while maintaining equipment accessibility and ease of setup.
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
Enhances safety by preventing short circuits, improving thermal management, reducing weight, and ensuring consistent quality through ultrasonic welding at room temperature, while being retrofittable and modular.
Implementation Method 1
ensuring consistent quality through ultrasonic welding at room temperature
Data Source
AI summary
An interconnector, for connecting a plurality of cells in a battery pack, includes: a main interconnect segment for connecting the plurality of cells, the main interconnect segment having a plurality of openings between a first end and a second end of the main interconnect segment, the plurality of openings being adapted to respective terminals of the plurality of cells in the battery pack; and a plurality of wire bonds connecting the main interconnect segment to the terminals of the plurality of cells, the respective plurality of wire bonds at one end being connected to the terminals of the respective plurality of cells, the respective plurality of wire bonds at another end being connected to a plurality of connecting portions on the main interconnect segment, the plurality of connecting portions being substantially close to the respective terminals of the plurality of cells.