Auxiliary Charging Module for Battery Cell Voltage Equalization
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Solution Overview
Problem
Existing equalization methods for lithium-ion battery packs either require complex and costly active components or result in incomplete charging due to insufficient equalizing current, leading to reduced battery lifespan and inconsistent charging states.
Innovation Solution
An equalization circuit with a detection module, an auxiliary small current charging module, and a control module that adjusts charging based on voltage, temperature, and current differences between cells, enabling targeted charging and discharging to ensure full charging and prolong battery life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If passive equalization using resistors is used, then the equalization circuit is simple and easy to promote, but the equalizing current is insufficient and complete charging cannot be achieved
Solution Approach 1:
The patent combines the simple passive equalization circuit with an auxiliary charging device to create a hybrid system. The passive equalization circuit handles voltage balancing between cells, while the auxiliary charging device provides additional current to ensure complete charging, thus merging the advantages of both approaches.
Solution Approach 2:
The auxiliary charging device acts as an intermediary component that bridges the gap between the limited equalizing current of passive equalization and the requirement for complete charging. It provides supplemental current specifically when equalization is needed, without interfering with normal charging operations.
2Productivity
If active equalization using DC converters is used, then complete charging can be achieved, but the peripheral circuit becomes complex and costs increase
Solution Approach 1:
The patent extracts only the essential function of active equalization (providing supplemental current) and implements it through a simplified auxiliary charging device rather than using a full DC converter system. This extracts the necessary capability while removing the complex peripheral circuits associated with conventional active equalization.
Solution Approach 2:
The auxiliary charging device uses cost-effective components compared to full active equalization systems with DC converters. The system accepts that the auxiliary charging function is only needed temporarily during equalization phases, allowing the use of simpler, more economical components that suffice for this specific intermittent function.
3Speed
If charger current is much greater than equalizing current, then fast charging is achieved, but voltage differences between cells cannot be eliminated
Solution Approach 1:
The system employs periodic action by activating the auxiliary equalization circuit only during specific phases when voltage differences between cells are detected. The high-current charger operates continuously for fast charging, while the auxiliary equalization circuit is periodically engaged to correct voltage imbalances, thus alternating between speed optimization and consistency maintenance.
Solution Approach 2:
The system uses feedback mechanisms to monitor voltage differences between cells during charging. When voltage inconsistency exceeds a threshold, the control system activates the auxiliary charging device to provide equalizing current. This closed-loop feedback ensures that fast charging continues unless voltage imbalance occurs, at which point equalization is automatically initiated.
Data Source
AI summary
The present invention relates to an equalization circuit, a charging device, and an energy storage device connected between a battery pack and a charger. The battery pack comprises a plurality of cells connected in series. The equalization circuit comprises: a detection module used for detecting a voltage, temperature, and/or current of each cell; an auxiliary charging module used for providing a second charging current to the battery pack, wherein the second charging current is less than a first charging current provided by the charger to the battery pack; and a control module used for controlling the detection module and the auxiliary charging module.