Battery Pack Balancing via Voltage Change Detection
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Solution Overview
Problem
Conventional battery pack balancing methods are inefficient for large capacity packs, requiring extended balancing times which increase power dissipation and heat, and stress on components, while being ineffective during low voltage change periods.
Innovation Solution
A method and system that determine whether the current period is a high or low voltage change period, initiating balancing only during high voltage changes and maintaining it based on a calculated balancing time, using a voltage sensing and balancing circuit with a control unit to select balancing object cells and execute balancing operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If balancing current is increased to reduce balancing time, then balancing time is reduced, but power dissipation and heat increase and stress is applied to elements
Solution Approach 1:
The patent applies preliminary action by detecting voltage changes during charging/discharging cycles and proactively initiating balancing operations before significant voltage deviations occur. The control unit monitors voltage changes in real-time and starts balancing when voltage deviation exceeds a threshold, preventing the need for high-current balancing later while reducing overall balancing time and power dissipation.
2Productivity
If balancing operation is executed after charging in conventional method, then balancing is possible in small capacity battery pack in short time, but balancing is impossible within the same short time in large capacity battery pack
Solution Approach 1:
The patent applies dynamics by adapting the balancing strategy based on battery pack capacity and voltage change characteristics. For large capacity packs, the system detects high voltage change periods during charging/discharging and initiates balancing operations during these periods when voltage deviations are most pronounced, rather than using a fixed post-charging balancing approach. This dynamic adaptation enables effective balancing across different pack sizes.
Solution Approach 2:
The patent changes the parameter of when balancing is executed - shifting from a fixed time-based approach (after charging) to a condition-based approach (during high voltage change periods). The control unit monitors voltage change rates and initiates balancing when dV/dt exceeds a threshold, allowing the system to optimize balancing timing based on actual electrical conditions rather than following a rigid schedule, thereby improving efficiency for large capacity packs.
3Stability of the object's composition
If balancing is maintained during low voltage change period, then voltage evenness is improved, but power dissipation increases unnecessarily
Solution Approach 1:
The patent applies periodic action by executing balancing operations only during specific periods when voltage changes are detected (high voltage change periods). The control unit continuously monitors voltage variations and activates balancing intermittently based on detected voltage change patterns, rather than maintaining continuous balancing. This periodic activation during high voltage change periods achieves voltage evenness while minimizing unnecessary power dissipation during low voltage change periods.
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 reduces balancing time and power dissipation in large capacity battery packs by focusing on high voltage change periods, ensuring efficient cell balancing without excessive stress or heat, thereby extending battery life and maintaining stable performance.
Implementation Method 1
a voltage sensing and balancing circuit configured to measure a voltage of each battery cell of a battery pack
Implementation Method 2
provide a balancing current path for each battery cell
Implementation Method 3
power dissipation is not only increased, but also heat is increased in the battery pack
Data Source
AI summary
A balancing method and balancing system of a battery pack is disclosed. The method includes and the system is capable of determining whether a voltage change of the battery pack is greater than a threshold during a charging or discharging period, and balancing the battery cells based on the voltage change being greater than a threshold.