Battery Pack Cell Bypass Timing for Weak Cell Management
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Solution Overview
Problem
Existing battery management systems face challenges in efficiently managing rechargeable batteries, particularly in identifying and mitigating the impact of deficient or defective battery cells, which can lead to reduced performance and lifespan of battery packs.
Innovation Solution
A battery management system that monitors the voltage across battery cells and determines their capacity, selectively bypassing deficient or defective cells during charging and discharging cycles to minimize their negative impact, using a control circuit to manage charging and discharging switches and determine bypass periods based on cell capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional hardware-based balancing methods are used to manage battery cells, then battery cell balancing can be achieved, but the system becomes expensive and complex
Solution Approach 1:
The patent replaces traditional hardware-based balancing circuits with a software-controlled method. The control circuit uses voltage monitoring and software logic to identify deficient cells and execute bypass sequences, substituting complex hardware balancing mechanisms with a more simplified software-driven approach that reduces device complexity while maintaining balancing functionality
Solution Approach 2:
The patent extracts and isolates the problematic deficient battery cells by bypassing them through switching circuitry. The control circuit identifies cells with voltage outside the acceptable range and selectively removes them from the active charging/discharging path, allowing the remaining healthy cells to operate independently without being constrained by the deficient cells
2Reliability
If battery management systems monitor and manage each cell individually, then cell health can be maintained, but the system cost increases
Solution Approach 1:
The control circuit performs multiple functions using a single integrated unit: it monitors voltage across all battery cells, determines capacity based on voltage changes, identifies deficient cells, and executes bypass sequences. This multi-functional approach eliminates the need for separate dedicated circuits for each function, reducing overall system cost while maintaining comprehensive cell health management
Solution Approach 2:
The battery management system uses the existing voltage monitoring capability to automatically detect deficient cells and trigger bypass sequences without requiring external intervention or additional specialized sensors. The system serves itself by using its own monitoring data to make management decisions, reducing the need for extra costly components
Data Source
AI summary
A system can include a battery pack with battery cell sections connected in series, where each of the battery cell sections includes a battery cell and a bypass switch. The system can also include a control circuit. The control circuit can determine a capacity of a particular battery cell in a particular battery cell section, determine that the capacity of the particular battery cell is less than a predefined threshold, and in response, execute a bypass sequence for the particular battery cell. The bypass sequence can involve determining a bypass period for which to bypass the particular battery cell based on the capacity of the particular battery cell, and transmitting a bypass signal to a drive circuit. The drive circuit can receive the bypass signal and responsively operate the bypass switch of the particular battery cell section to bypass the particular battery cell for the bypass period.