Parallel Battery Charge Control Circuit with Differential Amplifier
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Solution Overview
Problem
Existing battery protection circuits fail to ensure uniform charging currents across secondary batteries connected in parallel, despite protecting against overcurrent, due to differences in capacitance and impedance values.
Innovation Solution
A charge/discharge control circuit with a voltage detection circuit, differential amplifier, and output circuit that adjusts charging signals for each battery, using resistors to monitor and equalize charging currents, ensuring uniform charging even with varying capacitance and impedance values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If secondary batteries are connected in parallel with different capacitance or impedance values, then the battery capacity and current supply capability are improved, but the charging currents become non-uniform causing overcharging risks
Solution Approach 1:
The patent divides the charging control into separate segments for each battery string. Independent charge control terminals (first charge control terminal and second charge control terminal) are provided for each parallel-connected battery string, allowing individualized charging control signals to be applied to each string based on its specific characteristics, thereby achieving uniform charging currents despite different capacitance or impedance values.
Solution Approach 2:
The patent applies different charging control characteristics to different battery strings based on their local properties. The voltage detection circuit and charge control circuit generate customized charging control signals for each battery string, taking into account the specific voltage characteristics and impedance of each string, thus ensuring that each string receives appropriate charging current tailored to its needs.
2Reliability
If protection circuits are added to prevent inrush current, then battery safety is improved, but the charging control capability for uniform current distribution is lost
Solution Approach 1:
The patent merges the protection function and the uniform charging control function into a single integrated charge/discharge control circuit. The voltage detection circuit monitors voltages across different battery strings and the charge control circuit simultaneously performs both protection (preventing inrush current and overcharging) and uniform charging control (adjusting charging currents to be equal across strings), eliminating the need for separate protection circuits.
Solution Approach 2:
The charge/discharge control circuit is designed with multi-functionality, serving both as a protection circuit and as a uniform charging control circuit. It can detect voltage differences, prevent inrush current, and actively regulate charging currents to be uniform across parallel-connected battery strings with different characteristics, thus performing multiple functions within a single circuit architecture.
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
Enables uniform charging currents across secondary batteries connected in parallel, preventing overcharging and ensuring safe operation by maintaining charging currents within rated limits, even with differences in capacitance and impedance.
Implementation Method 1
a voltage detection circuit which outputs a control signal controlling the charging and discharging according to voltages of the positive power supply terminal, the first negative power supply terminal, and the second negative power supply terminal
Implementation Method 2
a first voltage input terminal connected to one end of a first resistor through which a current of the first secondary battery flows, the first resistor having another end connected to the external negative terminal, a second voltage input terminal connected to one end of a second resistor through which a current of the second secondary battery flows
Data Source
AI summary
There are provided a charge/discharge control circuit which is equipped with a differential amplifier configured to detect charging currents of a plurality of secondary batteries connected in parallel, and a charge control circuit configured to output an output signal of the differential amplifier to charge control terminals according to a reception of a control signal to permit the charging of each of the secondary batteries, and which is capable of charging the secondary batteries connected in parallel with uniform charging currents, and a battery apparatus equipped with the charge/discharge control circuit.