Bidirectional Battery Charging Control for Balanced Multi-Cell Power
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Solution Overview
Problem
Charging and discharging multiple rechargeable batteries in electronic devices, such as smart glasses, is challenging due to size and weight limitations, leading to inefficiencies in power delivery, unbalanced charging, and potential damage from excessive voltages or currents.
Innovation Solution
Implementing a bidirectional controller system that manages charging and discharging currents and voltages across a shared power bus, reducing resistance and allowing flexible power supply connections, while balancing discharge between batteries and protecting against overcharge and over-discharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multiple batteries are included to provide additional power supply capacity, then power supply capacity is improved, but power connection resistance increases and charging efficiency deteriorates
Solution Approach 1:
The patent combines multiple batteries (first battery and second battery) into a unified power system with a common power bus, allowing them to work together as a single power source. This merging approach increases total power capacity while sharing common connection paths, thereby reducing overall connection resistance compared to separate charging systems.
2Power
If multiple power connections are used to charge multiple batteries, then power supply capacity is improved, but connection resistance increases and adversely impacts charging efficiency
Solution Approach 1:
The patent merges multiple battery charging paths into a single common power bus system. Instead of using separate power connections for each battery, the first and second batteries both connect to the same power bus, reducing the total number of power connections and their associated resistances.
3Power
If batteries are connected in series to increase voltage, then power capacity is improved, but voltage exceeds protection circuit limits and battery safety deteriorates
Solution Approach 1:
The patent connects multiple batteries in parallel configuration rather than series, maintaining the same voltage level across all batteries. This equipotential connection approach allows the system to increase current capacity without exceeding voltage limits of protection circuits, thereby ensuring battery safety while still improving overall power capacity.
4Power
If multiple chargers are used to charge multiple batteries, then power supply capacity is improved, but device complexity increases
Solution Approach 1:
The patent implements a universal power bus that can charge multiple batteries simultaneously through a single charging interface. The power bus serves multiple functions: it can charge the first battery, the second battery, or both together, eliminating the need for multiple dedicated chargers and reducing system complexity.
5Power
If parallel connected batteries are used to increase capacity, then power supply capacity is improved, but unbalanced charging and discharging occurs
Solution Approach 1:
The patent incorporates control circuits that monitor the charging and discharging states of parallel-connected batteries and provide feedback control. This allows the system to detect voltage and current differences between batteries and adjust charging/discharging currents dynamically to maintain balance and prevent uncharged or overcharged conditions.
Data Source
AI summary
In a general aspect, an electronic device can include a first battery cell, a second battery cell, a system power bus and a system load coupled with the system power bus. The device can also include a first bidirectional controller that is operationally coupled between the system power bus and the first battery cell. The first bidirectional controller can be configured to control a charging current and a charging voltage of the first battery cell, control a discharge current of the first battery cell. The device can further include a second bidirectional controller operationally coupled between the system power bus and the second battery cell. The second bidirectional controller can be configured to control a charging current and a charging voltage of the second battery cell, and control a discharge current of the second battery cell.