Battery Bypass Device Using Series Diodes and Plunger
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing battery bypass systems are unreliable due to premature activation from single diode failures, inefficient heat transfer, and unpredictable molten material flow, leading to potential overheating and fire risks, especially in spacecraft applications where storage capacity loss can be catastrophic.
Innovation Solution
A battery system with a normally open bypass circuit using two diodes in series, a meltable material like paraffin wax, and a plunger mechanism activated by heat from the diodes to close a shorting gap, ensuring reliable electrical bypass without overheating, even at lower currents, and maintaining durability through mechanical contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single diode is used in the bypass circuit, then the device complexity is reduced, but the reliability deteriorates due to premature activation from diode failure
Solution Approach 1:
The single diode is segmented into two diodes connected in series. This segmentation ensures that both diodes must fail for premature activation to occur, thereby improving reliability while maintaining relatively simple circuit complexity. The series connection creates a redundant configuration where the bypass remains inactive unless both diodes fail, preventing false activation.
2Device complexity
If heat is transferred through a thermal path from diode to fusible material, then the activation mechanism is simplified, but the efficiency deteriorates due to heat dissipation
Solution Approach 1:
The fusible material is extracted from the heat transfer path and replaced with a plunger mechanism that is directly heated by the diodes. This eliminates the intermediate thermal path that causes heat dissipation, improving energy efficiency. The plunger is positioned such that it receives heat directly from the diodes, ensuring reliable activation with minimal energy loss.
3Device complexity
If fusible material is used to close the shorting gap, then the activation process is simplified, but the reliability deteriorates due to unpredictable molten flow
Solution Approach 1:
A plunger is introduced as an intermediary between the heat source (diodes) and the shorting gap. The plunger is heated by the diodes and uses its thermal expansion or phase change to mechanically close the shorting gap. This intermediary provides controlled and predictable gap closure, improving reliability while maintaining simple overall device complexity.
4Power
If the bypass activates at high current, then the heat generation is sufficient for activation, but the productivity deteriorates due to delayed response and potential cell damage
Solution Approach 1:
The activation parameters are changed by using a plunger with lower melting point or phase change temperature compared to traditional fusible materials. This allows the plunger to activate at lower currents and temperatures, enabling faster response time while generating sufficient heat for reliable activation. The parameter change optimizes both power requirements and activation speed.
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 provides a fault-tolerant, reliable electrical bypass that activates only when necessary, preventing storage capacity loss and reducing the risk of overheating, ensuring continued operation of batteries even with defective cells, while minimizing the risk of premature activation and internal short circuits.
Implementation Method 1
the heat from the diodes creates an effective thermal path to the fusible material 24, such that the fusible material 24 melts
Implementation Method 2
the fusible material 24 is heated and melted by the heat produced by the diode 22
Data Source
AI summary
A low energy activation, fault tolerant, battery system includes an electrical storage cell having a positive terminal and a negative terminal. The electrical storage cell is provided with a normally open bypass circuit path that is closed in the event of an overdischarged, or open-circuit failure of, the electrical storage cell. The bypass circuit path includes a first electrical conductor connected to the negative terminal of the electrical storage cell, a second electrical conductor connected to the positive terminal of the electrical storage cell, and a shorting gap between the first electrical conductor and the second electrical conductor. The first and second electrical conductors and a non-conductive carrier at least partially enclose a heat source activatable upon the occurrence of the failed cell, a mass of a meltable material that is heated by the heat source, a plunger having an electrically conductive face, and a spring that is positioned to force the plunger into the mass of the meltable material when it is at least partially molten. The heat source includes two diodes connected in electrical series, each of which is operable to melt at least a portion of the mass of the meltable material. When the spring forces the plunger into the meltable material, the electrically conductive face of the plunger head physically contacts the first and second electrical conductors to eliminate the shorting gap so that the first electrical conductor is in electrical communication with the second electrical conductor.