Assembled Battery Voltage Detection Circuit with Constant Potential Midpoint
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Solution Overview
Problem
Conventional assembled battery total voltage detection circuits require an additional A/D converter and high resistance for voltage division, increasing production costs and reducing current through detection terminals, necessitating costly gold-plated terminals for reliability.
Innovation Solution
A differential amplifier circuit with a buffer, operated by a single power supply, is used to measure voltage divided by a divider resistor between the plus and minus terminals of an assembled battery, with a constant electric potential applied to the midpoint of the divider resistor, allowing the main control circuit to measure the voltage without an insulation power source and reducing impedance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an A/D converter and insulation power source are added to measure battery voltage, then voltage measurement capability is improved, but production cost increases
Solution Approach 1:
The patent extracts and eliminates the insulation power source and A/D converter from the conventional circuit configuration. By using the main control circuit's existing A/D converter and removing the insulation power source, the circuit achieves voltage measurement without requiring additional insulation components, thereby reducing production cost while maintaining measurement capability
Solution Approach 2:
The main control circuit's A/D converter is made multi-functional by using it for both general control functions and battery voltage measurement. The single power supply configuration allows the same power source to serve both the control circuit and voltage measurement functions, eliminating the need for a separate insulation power source
2Measurement precision
If high resistance is used in the voltage divider to increase voltage division ratio, then voltage measurement range is improved, but current through detection terminal decreases
Solution Approach 1:
The patent changes the resistance value parameter of the voltage divider from high resistance to low resistance. This parameter change increases the current through the detection terminal, improving contact reliability, while the voltage division ratio is maintained through appropriate selection of resistor values in the divider circuit
Solution Approach 2:
By using low resistance in the voltage divider, the patent enables the use of ordinary tinned contacts instead of expensive gold-plated terminals. The increased current through the terminal makes ordinary contacts sufficiently reliable, replacing expensive materials with cheaper alternatives
3Device complexity
If the midpoint of the divider resistor is connected to ground, then circuit simplicity is improved, but measurement accuracy deteriorates due to noise
Solution Approach 1:
The patent introduces a constant potential source as an intermediary between the midpoint of the voltage divider and ground. This constant potential source provides a stable reference voltage that is noise-resistant, acting as a mediator that prevents noise from the ground connection from affecting the measurement while maintaining circuit simplicity
Solution Approach 2:
The patent applies equipotentiality by connecting the midpoint of the voltage divider to a constant potential source, ensuring that the midpoint maintains a stable electric potential relative to ground. This eliminates potential fluctuations and noise that would otherwise affect measurement accuracy
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 configuration reduces production costs, eliminates the need for a special reference voltage source, and ensures reliable noise-resistant performance by increasing current through detection terminals, using less costly tinned contacts, while maintaining high reliability and detecting failures in the circuit.
Implementation Method 1
a differential amplifier circuit that amplifies voltage divided by the divider resistor
Implementation Method 2
a divider resistor connected between a plus terminal and a minus terminal of an assembled battery
Data Source
AI summary
An assembled battery total voltage detection circuit includes a main control circuit, a divider resistor connected between a plus terminal and a minus terminal of an assembled battery insulated from the main control circuit, and a differential amplifier circuit that amplifies voltage divided by the divider resistor. A constant electric potential relative to a ground of the main control circuit is applied to a midpoint of the divider resistor. The main control circuit measures the voltage divided by the divider resistor via the differential amplifier circuit.