Multi-Pack Battery Charging Using Pulse Grouping and Voltage Limits
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Solution Overview
Problem
In multi-pack battery systems, it is challenging to charge all battery packs to the same state of charge due to differences in open circuit voltage and internal resistance, leading to slow charging or less energy being stored than expected in some packs.
Innovation Solution
A method involving grouping battery packs by charge rates with minimal intra-group spread, using a sequence of charge and discharge pulses, and estimating relaxed discharge open circuit voltage to ensure all packs reach a predetermined operational voltage limit, allowing for faster and more balanced charging without violating critical voltage levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional charging methods are used on multi-pack battery systems, then charging can be performed, but the charging speed is slow and energy content stored is less than expected due to voltage and resistance differences between packs
Solution Approach 1:
The patent divides the multi-pack battery system into individual chargeable entities by monitoring each pack's voltage and charge rate separately. The controller identifies packs that can accept charge at the desired rate and isolates them for charging, while leaving other packs uncharged. This segmentation allows the system to charge at maximum speed without being constrained by the slowest pack, thereby improving charging speed while maximizing energy storage in eligible packs.
2Stability of the object's composition
If charging continues until all packs reach the same state of charge, then voltage balance is achieved, but the overall charging time increases significantly
Solution Approach 1:
The patent applies partial charging action by charging only those battery packs that can accept charge at the desired rate, rather than forcing all packs to reach identical state of charge. The controller charges packs individually or in groups based on their instantaneous charge acceptance capability, allowing the system to achieve sufficient voltage balance without the excessive time penalty of waiting for the slowest pack to catch up.
3Productivity
If higher charging voltages are applied to increase charging speed, then charging time decreases, but critical voltage limits may be violated
Solution Approach 1:
The patent applies local quality control by monitoring and controlling the charge rate and voltage of each individual battery pack separately. The controller adjusts charging parameters for each pack based on its specific state, allowing some packs to receive higher voltage charges when appropriate while maintaining safety limits. This localized control enables faster charging where possible while ensuring voltage limit compliance for all packs.
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 method increases the energy content stored in the electrical energy storage system while maintaining healthy voltage levels, potentially extending the system's lifetime by optimizing charge balancing and charging speed.
Implementation Method 1
Batteries are becoming a more common source of power for providing propulsion power to vehicles. Such batteries are rechargeable batteries and consist of several battery cells that may be connected in series and/or in parallel forming a complete battery pack for the vehicle.
Implementation Method 2
the open circuit voltage versus state of charge curves and internal resistances of the battery packs is often different between battery packs
Implementation Method 3
the open circuit voltage versus state of charge curves and internal resistances of the battery packs is often different between battery packs
Data Source
AI summary
A computer-implemented method and a system for charging an electrical energy storage system includes more than one electrical energy storage pack connected to a traction voltage bus of a vehicle.