Battery Pack Automated Discharging via Balancing Circuit
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Solution Overview
Problem
Existing battery packs require manual and time-consuming discharging to a safe state of charge (SoC) after fault events or reaching end of life, posing safety and efficiency challenges, especially for lithium-ion batteries which can experience thermal runaway and require specific shipping conditions.
Innovation Solution
A battery pack with a balancing circuit and microcontroller that measures operational values of each cell, selectively discharges cells across the balancing circuit to a desired SoC, and includes a battery management system to communicate with the microcontroller for automated discharging, ensuring safe storage, disposal, or transportation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If manual discharging is used to reduce battery pack to desired SoC, then safety is improved, but time consumption and labor intensity increase
Solution Approach 1:
The battery pack performs discharging automatically through its own balancing circuit and control system, eliminating the need for external manual intervention. The microcontroller monitors cell voltages and activates balancing resistors to discharge individual cells autonomously, making the system self-sufficient in achieving the desired SoC level.
Solution Approach 2:
The patent replaces manual mechanical operations with an electronic control system. Instead of physically connecting external discharge loads, the system uses electronic balancing circuits with controlled resistive discharge paths, substituting human-operated mechanical processes with automated electronic control.
2Productivity
If automated discharging system is implemented, then productivity is improved, but device complexity increases
Solution Approach 1:
The balancing circuit is designed to serve dual functions: during normal operation, it performs cell balancing to maintain equal charge levels across cells, and during fault conditions or end-of-life scenarios, it automatically discharges the battery pack to a safe SoC level. This multi-functionality eliminates the need for separate discharge circuitry.
Solution Approach 2:
The microcontroller continuously monitors the voltage of each battery cell through the balancing circuit and uses this feedback information to determine when discharge is needed and when the desired SoC level has been reached. This closed-loop feedback control automates the discharging process while maintaining simplicity in the control logic.
3Manufacturing precision
If selective cell discharging is performed, then manufacturing precision is improved, but measurement precision requirements increase
Solution Approach 1:
The system applies different discharge actions to different cells based on their individual voltage levels. Each cell is monitored and discharged independently through its associated balancing resistor when needed, allowing precise local control of discharge current for each cell rather than uniform discharge of the entire pack.
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
Automated discharging ensures safe and efficient reduction of battery packs to a desired SoC, reducing manual intervention and risk, while adhering to regulatory requirements like IATA's 30% SoC limit for lithium-ion batteries, facilitating safe handling and transportation.
Implementation Method 1
The balancing circuit is configured to measure the operational values of each of the battery cells
Implementation Method 2
issue commands to selectively discharge one or more of the battery cells across the balancing circuit
Data Source
AI summary
A battery pack configured for discharging to a desired state of charge (SoC) after a fault event that includes a plurality of battery cells and a balancing circuit connected to each of the battery cells. The balancing circuit is configured to measure operational values of each of the battery cells. The battery pack further includes a microcontroller configured to receive the operational values from the balancing circuit, compare the operational values to a prescribed threshold values and issue commands to selectively discharge one or more of the battery cells across the balancing circuit.