Battery Management System Isolating Charge Discharge FET During Storage
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Solution Overview
Problem
Lithium-ion batteries in information handling systems face premature discharge during storage due to self-discharge and power consumption by components like the battery level gauge circuit and power management controller, leading to over-discharge and potential damage.
Innovation Solution
A battery management system that includes a charge/discharge FET and a controller with firmware to monitor elapsed time and battery parameters, isolating the battery from system load and entering a minimum power state to reduce power consumption and extend battery life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the battery is left connected to system components during storage, then the system remains operational and ready for use, but the battery discharges prematurely due to continuous power consumption by components like the battery level gauge circuit and power management controller
Solution Approach 1:
The system performs preliminary detection of storage state and activates power reduction measures before critical discharge occurs. The controller monitors elapsed time since last communication and battery parameters, then proactively isolates the battery and enters minimum power state to prevent over-discharge damage
Solution Approach 2:
The system dynamically adjusts its power consumption state based on storage conditions. It transitions from normal operational power consumption to reduced power consumption in minimum power state, and further to near-zero consumption when battery is isolated by turning off the charge/discharge FET
2Measurement precision
If the controller continuously monitors battery parameters and maintains communication, then the battery status is accurately tracked, but power consumption increases reducing storage time
Solution Approach 1:
The controller monitors elapsed time since last system management bus communication and uses this time-based trigger to determine when to reduce monitoring frequency. Instead of continuous monitoring, it periodically checks battery parameters based on elapsed time thresholds, reducing power consumption while maintaining adequate surveillance
Solution Approach 2:
The system uses the elapsed time measurement itself as the trigger for action. By monitoring how long since last communication has been, the system automatically determines when to transition to power-saving modes without requiring external intervention or complex decision logic
3Ease of operation
If the charge/discharge FET remains on during storage, then the battery can be quickly recharged when needed, but power is continuously drawn from the battery extending discharge time
Solution Approach 1:
The system determines storage state in advance and proactively turns off the charge/discharge FET before critical discharge occurs. This preliminary action isolates the battery from system load, preventing continuous power draw while the system is in storage mode
Solution Approach 2:
The charge/discharge FET state is dynamically controlled based on detected storage conditions. The controller monitors battery parameters and elapsed time, then adjusts FET state accordingly - keeping it on during normal operation for quick recharging, but turning it off during storage to minimize discharge
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 solution effectively extends the time until the battery reaches an over-discharged state by reducing power consumption, thereby preventing premature failure and damage.
Implementation Method 1
A battery management system includes a battery and a charge/discharge field effect transistor (FET) coupled to the battery
Implementation Method 2
Additionally, cell self discharge operates to lower the amount of stored energy over time
Data Source
AI summary
A computer-implemented method extends the time until the battery reaches an over-discharged state of an information handling system during storage. The method comprises determining if a first battery parameter is outside an associated first battery parameter specification. When the first battery parameter is outside the associated first battery parameter specification, a power management controller isolates the battery by turning off a charge/discharge field effect transistor. The method also includes determining if the first battery parameter is outside an associated second battery parameter specification. In response to the first battery parameter being outside the associated second battery parameter specification, the power management controller is triggered to enter a minimum power state to further reduce power consumption from the battery.