Nickel Metal Hydride Battery Regeneration via Parallel Overcharge
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Solution Overview
Problem
Nickel metal hydride batteries face capacity limitations due to positive electrode restrictions and hydrogen leakage, leading to decreased discharge reserve and battery performance, especially when overcharging causes electrolyte decomposition and insufficient electrolyte levels.
Innovation Solution
Connecting nickel metal hydride batteries in parallel and using a charge unit with a control system to overcharge them, releasing oxygen gas through safety valves to restore the discharge reserve of the negative electrode, thereby maintaining hydrogen absorption in the alloy and preventing electrolyte depletion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If batteries are connected in series and overcharged for regeneration, then the discharge reserve can be restored, but the charging time is prolonged and electrolyte decomposition occurs
Solution Approach 1:
Multiple battery modules are connected in parallel to form a battery assembly, allowing simultaneous overcharging of all modules. This merging approach enables collective regeneration that significantly reduces total charging time compared to sequential processing, while maintaining effective discharge reserve restoration through synchronized valve opening
2Reliability
If overcharging is performed to restore discharge reserve, then hydrogen absorption capacity is maintained, but electrolyte decomposition and insufficient electrolyte levels occur
Solution Approach 1:
The safety valve, originally designed to release pressure during normal operation, is utilized during overcharging to release oxygen gas. This converts the potential harmful effect of oxygen generation into a beneficial function that prevents oxygen from reacting with hydrogen and maintaining hydrogen absorption capacity, while the parallel connection configuration minimizes electrolyte decomposition by reducing overall charging time
3Reliability
If batteries are regenerated one at a time in mass production, then the discharge reserve can be restored, but the productivity is reduced
Solution Approach 1:
Multiple battery modules are combined in parallel within a single battery assembly, enabling simultaneous regeneration of all modules through one overcharging operation. This merging approach transforms the low-productivity sequential regeneration process into a high-productivity parallel process, restoring discharge reserve for all batteries at once without requiring individual processing
4Reliability
If safety valve opens at different times in series-connected batteries, then oxygen generation varies, but the charging process becomes unbalanced and extends duration
Solution Approach 1:
By connecting battery modules in parallel, the system achieves equipotentiality where all modules experience the same voltage and charge conditions simultaneously. This ensures that safety valves open at synchronized times across all modules, balancing oxygen generation and enabling the charging process to complete in the time required for a single module rather than extending through multiple sequential cycles
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
This method efficiently regenerates nickel metal hydride batteries by synchronizing valve opening times, reducing the risk of electrolyte insufficiency and micro-short circuits, thereby enhancing battery performance and capacity without prolonging charging times.
Implementation Method 1
The hydrogen absorbing alloy absorbs hydrogen when the battery is charged and releases hydrogen when the battery is discharged
Implementation Method 2
a safety valve that opens when an internal pressure of a battery case is greater than or equal to a predetermined pressure
Implementation Method 3
when each nickel metal hydride battery is overcharged, restoring a discharge reserve of a negative electrode of the overcharged nickel metal hydride battery by releasing at least some of an oxygen gas generated at a positive electrode
Data Source
AI summary
A method for regenerating a nickel metal hydride battery is provided. The nickel metal hydride battery includes a hydrogen absorbing alloy that serves as a negative electrode material and a safety valve that opens when an internal pressure of a battery case is greater than or equal to a predetermined pressure. The method includes connecting a plurality of nickel metal hydride batteries in parallel. Each nickel metal hydride battery is formed by integrating one or more battery cells. The method further includes overcharging the nickel metal hydride batteries by supplying current from a charge unit that is connected in parallel to the nickel metal hydride batteries. The method further includes, when each nickel metal hydride battery is overcharged, restoring a discharge reserve of a negative electrode by releasing at least some of an oxygen gas generated at a positive electrode out of the battery case through the safety valve.