Battery Voltage Detection Device With Inverted Low-Pass Filter
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Solution Overview
Problem
Existing battery voltage detection systems risk underestimating inter-terminal voltages due to capacitor deterioration, potentially leading to missed overcharge alerts.
Innovation Solution
A battery voltage detection device with a low-pass filter configuration where one end of the capacitor is connected to the battery and the other end is connected to a voltage source outputting a voltage higher than the terminal voltage, preventing voltage detection errors caused by capacitor degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the capacitor is connected to ground terminal, then noise removal is achieved, but voltage detection accuracy deteriorates when capacitor deteriorates
Solution Approach 1:
The patent inverts the conventional connection configuration by connecting the capacitor to a voltage source terminal instead of ground terminal. This reversal changes the voltage division behavior: when capacitor deteriorates (internal resistance increases), the voltage at the detection terminal increases rather than decreases, preventing false low-voltage readings and maintaining accurate voltage detection throughout the capacitor's service life.
Solution Approach 2:
The patent changes the reference voltage parameter from ground (0V) to a positive voltage source. This parameter change transforms the voltage division relationship in the RC filter, ensuring that capacitor deterioration leads to voltage increase rather than decrease at the detection terminal, thereby maintaining measurement precision throughout the component's lifetime.
2Object-affected harmful factors
If RC filter is used for noise removal, then noise is reduced, but voltage detection reliability deteriorates due to capacitor deterioration
Solution Approach 1:
By inverting the capacitor connection from ground to voltage source terminal, the patent ensures that capacitor deterioration produces a voltage increase rather than decrease. This inversion maintains reliable voltage detection throughout the capacitor's service life, preventing false readings that would compromise system reliability.
Solution Approach 2:
The patent accepts that the capacitor will deteriorate over time (short-living component) but designs the circuit so that this inevitable deterioration does not compromise reliability. The inverted connection ensures that even as the capacitor degrades, the voltage detection remains reliable, effectively making the system tolerant of component aging.
3Duration of action of moving object
If capacitor internal resistance reduces due to deterioration, then capacitance increases, but voltage detection accuracy worsens
Solution Approach 1:
The patent inverts the voltage division relationship by connecting the capacitor to the voltage source terminal. This causes capacitor deterioration (increased internal resistance) to produce a voltage increase rather than decrease at the detection terminal, maintaining accurate voltage detection throughout the capacitor's extended service life.
Solution Approach 2:
The patent ensures continuous accurate voltage detection throughout the capacitor's service life by inverting the connection configuration. This maintains the useful action of accurate measurement continuously, even as the capacitor deteriorates and its electrical characteristics change over time.
Data Source
AI summary
A battery voltage detection device includes a battery; a voltage detection circuit; and a low-pass filter provided between the battery and the voltage detection circuit. The low-pass filter includes a capacitor of which one end is connected to a terminal of the battery and the other end is connected to a voltage source outputting a voltage higher than a terminal voltage of the battery.