Lead Acid Battery Charge Control via Current Monitoring
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Solution Overview
Problem
Lead acid batteries experience reduced lifetime due to side reactions during cyclic discharging and charging, leading to inefficiencies and eventual failure, particularly in motive power applications where frequent charging and discharging occur.
Innovation Solution
A method and apparatus that monitor current flow into and out of the battery during discharging phases, calculate the desired charge based on recorded information, and supply this calculated charge during charging phases, using a charge factor to optimize the charging process, thereby reducing side reactions and extending battery life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional charging systems (constant voltage, constant current, or hybrid) are used to charge lead acid batteries, then the battery can be charged efficiently, but side reactions occur during charging which waste energy and gradually cause changes in battery electrochemistry resulting in reduced battery lifetime
Solution Approach 1:
The charging system incorporates a microprocessor that continuously monitors battery parameters (voltage, current, temperature) and adjusts the charging algorithm in real-time based on feedback from these measurements. This closed-loop control enables the system to optimize charging while minimizing harmful side reactions, thereby extending battery lifetime without compromising charging efficiency
Solution Approach 2:
The system dynamically changes charging parameters (voltage, current, temperature compensation) based on real-time battery state measurements. By adjusting these parameters according to actual battery conditions rather than using fixed charging profiles, the system achieves both efficient charging and reduced electrochemical degradation
2Stability of the object's composition
If equalisation charge is applied at predetermined intervals to equalise the state of charge of cells, then cell charge balance is improved, but additional side reactions are caused and battery lifetime is further reduced
Solution Approach 1:
The system uses continuous monitoring of individual cell voltages and temperatures to detect charge imbalances in real-time. When imbalances are detected, the microprocessor adjusts the charging current distribution to specific cells, eliminating the need for periodic equalisation charges while maintaining cell balance and reducing harmful side reactions
Solution Approach 2:
The system performs preliminary detection of cell charge imbalances during normal charging operation and corrects them immediately rather than waiting for predetermined intervals. This proactive approach maintains cell balance without requiring additional equalisation charging cycles that would cause extra side reactions
3Productivity
If the charging system continuously adjusts voltage to maintain constant current, then charging efficiency is improved, but the complexity of the control algorithm increases
Solution Approach 1:
The system employs a simplified piecewise linear charging algorithm that changes voltage parameters at specific state-of-charge thresholds rather than using complex continuous adjustment. This approach maintains high charging efficiency while significantly reducing algorithmic complexity and microprocessor requirements
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 approach extends the working lifetime of lead acid batteries by controlling the charge supplied during charging phases based on the net charge removed, reducing side reactions and improving cyclic capability, making the batteries more reliable for frequent use.
Implementation Method 1
During the lifetime of a lead acid battery it will typically be discharged and charged many times
Implementation Method 2
supplying that desired amount of charge to the battery
Data Source
AI summary
The invention relates to a method of operating a lead acid battery which undergoes discharging phases and charging phases in a cyclical fashion. The method involves monitoring the current discharged from the battery during a discharging phase and recording information relating to that current flow, such as the charge lost from the battery. During the subsequent charging phase, a desired amount of charge to be supplied to the battery is calculated based upon the recorded information, and then supplied to the battery.