Battery Power Balancing Using Shared Capacitor and Switch Network
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Solution Overview
Problem
Conventional battery power balancing systems using capacitors and switch loops are inefficient as they can only exchange energy between adjacent batteries, requiring a large number of capacitors and achieving low charge transfer efficiency, and fail to protect batteries from over-charging or over-discharging.
Innovation Solution
A battery power balancing apparatus comprising a battery selection circuit, bi-directional power converter, detection circuits, and control circuit that allows for the selection and charging/discharging of any battery in the pack, using a storage capacitor to maintain voltage within a predetermined range, and includes protective measures to prevent short circuits and over-charging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If capacitors and switch loops are used between every two adjacent batteries, then battery power balancing can be achieved, but the device complexity increases due to the large number of capacitors required
Solution Approach 1:
The patent merges the functions of multiple capacitors into a single shared capacitor that is coupled to all batteries through switch loops. Instead of having separate capacitors between each pair of adjacent batteries, one capacitor serves the entire battery pack by sequentially exchanging energy with different batteries through the controlled switching network.
Solution Approach 2:
The single shared capacitor performs multiple functions: it balances energy between any pair of batteries in the pack, protects batteries from over-charging and over-discharging, and can operate in different balancing modes (charging a battery or discharging a battery) depending on the state of charge of the batteries.
2Reliability
If capacitors and switch loops are used between every two adjacent batteries, then battery power balancing can be achieved, but the charge transfer efficiency decreases
Solution Approach 1:
The control circuit continuously monitors the state of charge of all batteries and uses this feedback information to intelligently control the switching network. It determines which battery should be charged and which should be discharged, and controls the switch loops to connect the shared capacitor to the appropriate batteries in sequence, maximizing charge transfer efficiency.
Solution Approach 2:
The system dynamically adjusts the switching configuration based on real-time battery states. The control circuit changes which switch loops are active and which batteries are connected to the capacitor, optimizing the balancing process adaptively rather than using a fixed configuration.
3Device complexity
If adjacent batteries only exchange energy with each other, then the system structure is simplified, but the adaptability decreases as energy cannot be freely exchanged between all batteries
Solution Approach 1:
The shared capacitor acts as an intermediary energy storage device that enables indirect energy exchange between any two batteries in the pack. Although batteries do not exchange energy directly with each other, the capacitor mediates the energy transfer by sequentially charging from one battery and discharging to another, achieving free energy exchange across all batteries.
Solution Approach 2:
The patent segments the battery pack into individual battery units, each with its own switch loop connections to the shared capacitor. This segmentation allows the control circuit to independently select and control energy exchange between any combination of batteries, providing flexible adaptability while maintaining a simple overall structure.
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 solution enables efficient battery power balancing across multiple batteries, protecting them from over-charging and extending their lifespan by allowing energy exchange between all batteries, improving utilization and reducing the need for numerous capacitors.
Implementation Method 1
a bi-directional power converter having a first terminal coupled to the charge and discharge port, and a second terminal coupled to a storage capacitor
Implementation Method 2
N detection circuits corresponding to the N batteries, where each of the N detection circuits is configured to detect a state of a corresponding of the N batteries
Data Source
AI summary
An apparatus for balancing battery power can include: a battery selection circuit coupled to N batteries, where the battery selection circuit is configured to couple one of the N batteries to a charge and discharge port, where N is an integer greater than 1; a bi-directional power converter having a first terminal coupled to the charge and discharge port, and a second terminal coupled to a storage capacitor; N detection circuits corresponding to the N batteries, where each of the N detection circuits is configured to detect a state of a corresponding of the N batteries; and a control circuit configured to control the battery selection circuit to couple a selected battery to the charge and discharge port, and to charge or discharge the selected battery through the bi-directional power converter to maintain a voltage of the storage capacitor to be within a predetermined range.