Battery Management Circuit for UVP Charger Detection
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Solution Overview
Problem
Lithium iron phosphate batteries face challenges with Under Voltage Protection (UVP) and Over Voltage Protection (OVP) modes, where they appear 'dead' to automatic chargers, leading to improper operation and potential damage from excessive voltage and current during charging, and existing systems fail to detect voltage in UVP mode or manage voltage and current effectively.
Innovation Solution
A battery management system that controls charge and charging of each cell individually, enabling voltage monitoring in UVP mode, regulating input voltage and current, and emulating a standard battery in OVP mode to prevent malfunctions, using a controller with precision voltage references and a voltage regulator to filter ripple and maintain stable charging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the battery enters Under Voltage Protection mode to prevent complete discharge, then the battery is protected from damage, but the battery appears dead to automatic chargers and cannot be detected for charging
Solution Approach 1:
The patent introduces a mediator circuit between the battery cells and the external charging system. This mediator includes a control system that can switch between different connection states: normally connecting the cells to the posts for charging, and alternatively disconnecting the cells while maintaining a simulated voltage signal. This intermediary mechanism allows the battery to appear charged to automatic chargers while actually being in protection mode, resolving the contradiction between protection and detectability.
2Reliability
If the control system disconnects the cell pack from the battery posts in protection modes, then the battery is protected from overcharge or complete discharge, but the measured voltage across the posts becomes zero and charging cannot proceed
Solution Approach 1:
The patent employs an intermediary voltage simulation circuit that generates a fake voltage signal at the battery posts when the actual cells are disconnected for protection. This simulated voltage maintains the appearance of a properly functioning battery, allowing accurate voltage measurement by external systems while the cells remain isolated and protected from harmful charging conditions.
3Productivity
If the charging system operates at high voltage and current to provide sufficient charging power, then charging speed is improved, but the high voltage and current can damage cells in lithium iron phosphate batteries
Solution Approach 1:
The patent divides the charging control into individual cell-level management rather than treating the battery as a single unit. The control system monitors and regulates charging current for each cell separately, preventing any single cell from receiving excessive current that could cause damage. This segmentation allows the system to utilize high overall charging power while distributing it safely across individual cells through precise current control.
Solution Approach 2:
The patent dynamically adjusts charging parameters (voltage and current) based on real-time cell state monitoring. The control system modifies charging parameters to match the actual needs of each cell, preventing harmful high current conditions while maintaining efficient charging. This parameter adaptation allows the system to operate at high power when safe and reduce power when cell conditions require gentler charging.
4Productivity
If the charging system produces high current to charge the battery quickly, then charging efficiency is improved, but the excessive current flow can damage battery cells and reduce battery life
Solution Approach 1:
The patent implements segmentation of current control at the individual cell level, where each cell's charging current is independently regulated. This prevents any single cell from receiving damaging excessive current while allowing the overall battery to charge efficiently. The control system distributes charging current intelligently across cells based on their individual states, maintaining high charging efficiency without compromising battery longevity.
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
Enables full charging of each cell, prevents battery damage, maintains system stability, and allows smart chargers to detect and charge batteries effectively, even in UVP mode, while ensuring safe operation and extended battery life.
Implementation Method 1
Charging systems often do not produce clean direct current. Rather, charging systems may create a great deal of ripple, which may cause improper charging of the battery packs cells leading to shortened lifetimes and damage.
Implementation Method 2
Charging systems can create excessive electrical potential and high current flow from the charging system. Charging systems can generate between about 12 Volts direct current to more than 20 Volts direct current at currents as high as 60 amps. Such high voltage and current can damage cells in lithium iron phosphate battery batteries.
Data Source
AI summary
A battery management system for batteries, such as, but not limited to, electric vehicle battery packs and cells, lithium iron phosphate batteries, lead acid batteries, gel batteries, and absorbed gel mat batteries, in engine start applications is disclosed. The battery management system is configured to control the charge and charging of each cell individually. The battery management system may be configured to control the charge of a battery which may consist of a plurality of cells, such as, but not limited to, lithium iron phosphate cells, and in at least one embodiment, the battery may consist of, but is not limited to being formed from, four lithium iron phosphate cells connected in series and a battery management system to ensure proper charge and safe operation.