Bipolar Overvoltage Battery Pulser for Capacity Retention
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Rechargeable batteries experience a loss in energy capacity and reduced lifespan due to progressive changes in the active materials at the anode and cathode during discharge and recharge cycles, leading to increased impedance and reduced ion transfer, which is not effectively addressed by existing charge sequencing strategies.
Innovation Solution
A bipolar overvoltage battery pulser that generates alternating positive and negative voltage pulses with specific rise times and amplitudes to impose overvoltage conditions, counteracting the memory effect and promoting equilibrium changes in the electrochemical system, thereby maintaining battery capacity and extending cycle life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional charging cycles are used, then batteries can be recharged, but capacity is lost over time due to progressive changes in active materials at electrodes
Solution Approach 1:
The patent applies periodic voltage pulses with alternating polarity (bipolar pulses) to the battery electrodes. These periodic electrical stimulations occur at specific frequencies and durations, creating cyclic overvoltage conditions that prevent the progressive crystallization of active materials and maintain porous surface structures, thereby preserving capacity over repeated charge cycles
Solution Approach 2:
The patent changes the electrical parameters by applying overvoltage pulses that exceed the normal operating voltage of the battery. These parameter changes include varying voltage amplitude, pulse duration, and frequency to create conditions that reverse the degradation processes occurring during conventional charging, maintaining the active material in a more reactive state
2Reliability
If deep discharge is performed before recharging, then capacity retention is improved, but the process is time-consuming and may not fully prevent deterioration
Solution Approach 1:
The patent applies preliminary electrical treatment in the form of bipolar overvoltage pulses before the battery undergoes conventional charging. This preliminary action resets the surface structure of the electrodes and prevents the formation of stable crystalline aggregates, preparing the active material to accept charge more effectively without requiring time-consuming deep discharge cycles
3Productivity
If repeated shallow discharge cycles occur, then batteries can remain in use, but capacity loss is exasperated compared to deep discharge followed by charging
Solution Approach 1:
The patent implements continuous or near-continuous application of bipolar voltage pulses during battery operation and charging. This continuous electrical treatment maintains the electrode surface in a favorable state throughout repeated shallow discharge cycles, preventing the cumulative capacity loss that occurs when batteries are repeatedly charged without proper conditioning
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 bipolar overvoltage battery pulser increases battery cycle lifetime by up to 250% and retains capacity by at least 150% more than untreated batteries, effectively addressing the capacity loss and lifespan reduction issues.
Implementation Method 1
applying a positive voltage pulse having a rise time of less than the relaxation time constant of the electrochemical cell thereby imposing an overvoltage condition on the electrochemical cell
Implementation Method 2
a positive voltage pulse having a rise time of less than the relaxation time constant of the electrochemical cell
Implementation Method 3
A rechargeable battery is an electrochemical cell that stores energy, delivering that energy upon discharge of current
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
A bipolar overvoltage battery pulser and method are provided that apply a positive pulse voltage and a negative pulse voltage alternately across the terminals of a battery. The object of the bipolar overvoltage battery pulser and method is to increase the cycle lifetime and capacity of storage batteries, such as lead acid batteries. The rise times for the leading edges of the positive pulses and for the trailing edges of the negative pulses are short compared to the ionic relaxation time in the electrochemical solution. Alternating between the positive and negative pulses gives each new pulse an equal starting condition without realizing any memory effect that otherwise may result if the last applied pulse was of the same polarity, which reduces the extent of overvoltage that may be applied to the battery and decrease the highest useable pulse cycling frequencies that could be achieved without experiencing pulse overlapping. The shape, type and timing of the pulses may be adjusted to create overvoltage pulses having high duration and amplitude.