Cell Balancing System Using Capacitor Switch Networks
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Solution Overview
Problem
Existing battery pack systems face inefficiencies in cell balancing, leading to uneven charging and discharging, which results in reduced usable energy and potential cell damage due to passive cell balancing methods that waste energy as heat.
Innovation Solution
A cell balancing system utilizing a combination of first and second balancer circuitries with switch networks and capacitors, allowing for efficient energy transfer between cells to equalize state of charge and voltage, reducing the time required for balancing and minimizing energy loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If passive cell balancing is used to equalize cell voltage, then cell voltage uniformity is improved, but energy is wasted as heat
Solution Approach 1:
The patent introduces a capacitor as an intermediary energy storage element between cells. Instead of directly dissipating energy from high-voltage cells through resistors, the capacitor temporarily stores energy from charged cells and releases it to discharged cells, enabling energy redistribution without heat loss.
Solution Approach 2:
The patent recovers energy that would otherwise be discarded as heat during passive balancing. By capturing energy in capacitors during the charging phase and releasing it during the discharging phase, the system recovers and reuse energy that would be lost in traditional passive balancing methods.
2Stability of the object's composition
If passive cell balancing is used to equalize cell charge, then cell charge uniformity is improved, but charging time is increased
Solution Approach 1:
The patent enables continuous useful action by operating in alternating charge and discharge phases. While one set of capacitors is charging from high-voltage cells, another set is discharging to low-voltage cells, ensuring that energy redistribution occurs continuously without idle periods, thereby reducing total balancing time.
Solution Approach 2:
The patent employs periodic action through alternating charge and discharge phases. The system switches between charging capacitors from certain cells and discharging capacitors to other cells in a periodic manner, accelerating the balancing process compared to continuous passive discharge methods.
3Reliability
If passive cell balancing is used to protect cells from overcharge, then cell safety is improved, but usable energy is reduced
Solution Approach 1:
The capacitor acts as a mediator that enables safe energy redistribution without direct cell-to-cell discharge. This intermediary approach maintains cell safety by preventing overcharge through controlled charge transfer while preserving usable energy that would be lost in passive balancing.
Solution Approach 2:
The system recovers energy that would be discarded during safety-based balancing operations. By capturing and redistributing energy that would otherwise be wasted when cells reach voltage thresholds, the patent maintains cell safety while maximizing usable energy utilization.
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
The system effectively reduces the time needed to balance cells and minimizes energy wastage, leading to more frequent charging intervals and a lower environmental impact by redistributing energy rather than dissipating it as heat.
Implementation Method 1
first balancer circuitry comprising a first set of capacitors and a first switch network... second balancer circuitry comprising a second set of capacitors and a second switch network
Data Source
AI summary
A cell balancing system for balancing a set of series-connected cells, the cell balancing system comprising first balancer circuitry and second balancer circuitry. The first balancer circuitry comprises a first set of capacitors and a first switch network. The first switch network is controllable such that in operation of the cell balancing system: during a first phase of operation of the first balancer circuitry, a capacitor of the first set of capacitors is coupled to a first cell of the set of series-connected cells; and during a second phase of operation of the first balancer circuitry, the capacitor of the first set of capacitors is coupled to a second cell of the set of series-connected cells. The second balancer circuitry comprises a second set of capacitors and a second switch network. The second switch network is controllable such that in operation of the cell balancing system: during a first phase of operation of the second balancer circuitry, a capacitor of the second set of capacitors is coupled to a first subset of cells of the set of series-connected cells, the first subset comprising two or more of the set of series-connected cells; and during a second phase of operation of the second balancer circuitry, the capacitor of the second set of capacitors is coupled to a second subset of cells of the set of series-connected cells, different than the first subset, the second subset comprising two or more of the set of series-connected cells.