Switching Circuitry for Lithium Ion Battery Module Charge Balancing
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Solution Overview
Problem
Existing charge balancing methods for lithium ion batteries, such as passive and active balancing, are inefficient and complex, especially during fast charging, which can lead to unwanted energy losses and over-charging risks due to high charging currents and voltage sensitivity.
Innovation Solution
A method and system that short-circuit fully charged battery modules while adjusting the voltage and current level supplied by the charger, using a balancing module with a controller and switching circuitry to ensure all modules reach full charge, thereby improving charge balancing efficiency and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If passive or active balancing methods are used during fast charging, then charge balancing can be achieved, but energy losses increase and system complexity increases
Solution Approach 1:
The patent extracts and removes fully charged battery modules from the charging circuit by short-circuiting them through switching circuitry. This allows the charging current to be redirected to remaining uncharged modules without energy loss through resistive dissipation, solving the contradiction between achieving charge balancing and minimizing energy losses.
Solution Approach 2:
Instead of actively transferring energy from charged to uncharged modules (active balancing) or dissipating energy through resistors (passive balancing), the patent inverts the approach by removing charged modules from the circuit entirely. This reversal eliminates the need for energy transfer or dissipation mechanisms, reducing both energy losses and system complexity.
2Productivity
If high charging current is used for fast charging, then charging speed improves, but over-charging risks increase due to voltage sensitivity
Solution Approach 1:
The patent implements a monitoring system that continuously tracks the voltage and charging status of each battery module. When a module reaches full charge voltage threshold, the system provides feedback to the controller, which then activates the switching circuitry to short-circuit and remove that module from the charging circuit, preventing over-charging while maintaining fast charging speeds.
Solution Approach 2:
The patent applies preliminary protective action by preemptively short-circuiting and removing fully charged modules from the circuit before over-charging can occur. This preliminary removal prevents the harmful effects of over-charging while allowing high charging currents to continue flowing to remaining uncharged modules, maintaining fast charging productivity.
3Ease of operation
If all battery modules are charged simultaneously at the same current level, then charging process is simple, but fully charged modules cannot be effectively balanced
Solution Approach 1:
The patent segments the battery system into individually monitored and controllable modules. Each module is equipped with voltage sensing and is independently managed by the controller through dedicated switching circuitry. This segmentation allows the system to identify and remove fully charged modules while continuing to charge remaining modules, achieving effective charge balancing while maintaining operational simplicity.
Solution Approach 2:
The patent introduces dynamic control to the charging process by enabling modules to be added or removed from the charging circuit in real-time based on their charge status. The switching circuitry dynamically reconfigures the circuit topology, transitioning from a static simultaneous charging approach to a dynamic selective charging approach that maintains both ease of operation and charge balancing efficiency.
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 enhances the efficiency of fast charging lithium ion batteries by utilizing the high charging current effectively, reducing energy losses, and ensuring all modules reach full charge without over-charging, particularly beneficial for batteries with metalloid-based anodes.
Implementation Method 1
short-circuiting fully charged modules while adjusting a voltage and/or current level supplied by a charger
Data Source
AI summary
Systems and methods are provided for balancing battery modules following fast charging, particularly with respect to fast charging lithium ion batteries with metalloid-based anodes. Charge balancing among multiple battery modules connected in series may be carried out by short-circuiting fully charged modules while adjusting the voltage and/or current level supplied by a charger, to fully charge remaining modules. A balancing module comprising a controller and switching circuitry may be configured to implement the charge balancing in association with the charger and its battery management system, and monitoring the battery modules. Advantageously, disclosed switching balancing is more efficient than prior art passive balancing and simpler in implementation than prior art active balancing.