Battery Pack Self-Discharge Circuit for Cell Imbalance
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Solution Overview
Problem
Batteries connected in series face cell imbalance issues during charging, where a lower-capacity battery can prevent full charging, leading to performance degradation, and conventional solutions require complex circuitry or low-voltage charging, which is not energy efficient.
Innovation Solution
A device and method that reduces the charging current of overcharged batteries by incorporating a self-discharge mechanism using a switching element, resistance element, and voltage-detecting element, allowing current leakage and balancing capacity among batteries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If batteries are connected in series to achieve high voltage, then efficiency increases and cost decreases, but cell imbalance occurs during charging causing performance degradation
Solution Approach 1:
The patent divides the series-connected battery system into individually monitorable units by introducing separate voltage detection circuits for each battery. This segmentation allows independent tracking of each battery's voltage state, enabling the system to identify and manage cell imbalance issues without affecting the entire series chain.
Solution Approach 2:
The patent introduces a controller as an intermediary component that receives voltage signals from detection circuits and manages the charging process. This mediator coordinates the charging current distribution among series-connected batteries, preventing overcharging of individual cells while maintaining overall system efficiency.
2Ease of operation
If conventional charging methods are used for series-connected batteries, then charging simplicity is maintained, but cell imbalance causes the overall battery capacity to be limited by the weakest cell
Solution Approach 1:
The patent implements a feedback mechanism where voltage detection circuits continuously monitor each battery's voltage during charging and provide real-time signals to the controller. The controller adjusts charging current based on this feedback, ensuring that no single battery becomes the limiting factor while maintaining automated operation.
Solution Approach 2:
The patent introduces dynamic current management where the charging current is automatically adjusted based on the real-time voltage states of individual batteries. This dynamic approach allows the system to optimize charging speed for each battery according to its specific state, maximizing overall capacity without manual intervention.
3Reliability
If batteries are charged separately to full capacity, then cell imbalance is avoided, but low voltage charging requires energy-inefficient conversion from high voltage AC power source
Solution Approach 1:
The patent changes the voltage parameter management approach by maintaining high voltage series connection during charging while using detection circuits and controllers to dynamically adjust current distribution. This allows efficient high-voltage charging while preventing cell imbalance, eliminating the need for inefficient low-voltage charging conversion.
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
Effectively alleviates cell imbalance by decreasing the charging current of overcharged batteries and increasing it for undercharged ones, achieving balanced charging without complex circuitry or low-voltage inefficiencies.
Implementation Method 1
a voltage-detecting element
Implementation Method 2
a switching element
Implementation Method 3
a resistance element
Data Source
Figure 1a~1c
Figure 1d~1e
Figure 2a
AI summary
A rechargeable battery, battery set or battery pack having a circuit or a plurality of circuits for providing self-discharging thereof electrically connected in parallel are used to form rechargeable battery assemblies and electric power supply systems for use in electric and hybrid vehicles and the like.