Battery Voltage Detection Fault Isolation via Dual-Path Comparison
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Solution Overview
Problem
Existing battery systems and voltage detection apparatuses fail to accurately detect in-range faults in battery voltage measurements, leading to potential overcharging or overdischarging of lithium-ion secondary batteries, as they cannot differentiate between minor faults and normal operating conditions within the predetermined voltage range.
Innovation Solution
A battery system with a voltage detection apparatus that includes an AD converter, a voltage level discrimination portion, and a fault detection portion, which compares the output of the AD converter with the voltage level discrimination results to identify faults within the predetermined voltage range, and a control portion that limits charging or discharging accordingly, using the smaller of the two voltage values to prevent damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a voltage detection apparatus uses an AD converter to detect battery voltage, then voltage detection is enabled, but in-range faults cannot be detected when the output voltage is within the normal voltage range
Solution Approach 1:
The voltage detection system is segmented into multiple detection paths: one for normal voltage range detection (AD converter) and another for fault detection (comparator with threshold voltage). This segmentation allows the system to detect both normal operating conditions and abnormal conditions independently, resolving the contradiction by enabling specialized detection for each function.
Solution Approach 2:
A comparator circuit acts as an intermediary between the AD converter output and the control system. The comparator introduces a reference threshold voltage that mediates the detection process, allowing the system to identify in-range faults by comparing the AD converter output against the threshold, thereby enabling fault detection without affecting normal voltage measurement.
2Device complexity
If the voltage detection system only checks for out-of-range values, then simple detection logic is maintained, but in-range faults lead to erroneous voltage detection
Solution Approach 1:
The system performs preliminary fault detection by comparing the AD converter output against a threshold voltage before final voltage determination. This preliminary action identifies potential in-range faults early in the detection process, allowing the control system to take appropriate measures and prevent erroneous voltage detection while maintaining relatively simple overall logic.
3Device complexity
If no fault detection mechanism is added, then the system remains simple, but in-range faults cause incorrect voltage readings and potential battery damage
Solution Approach 1:
The comparator circuit with threshold voltage provides beforehand cushioning against in-range faults. By preparing a reference threshold and comparison mechanism in advance, the system cushions against potential detection errors before they can cause battery damage, ensuring reliability while adding only minimal structural complexity.
Data Source
AI summary
A battery system has: a voltage detection apparatus including a voltage detection portion which includes an AD converter which converts an analog voltage signal having a measurement target analog voltage into a digital voltage signal to output the digital voltage signal, a voltage level discrimination portion which is connected to a voltage detection line across which the analog voltage signal is delivered, and which discriminates the voltage level of the measurement target analog voltage to output a discrimination result, and a fault detection portion which detects, based on the output of the AD converter and the output of the voltage level discrimination portion, a fault in the voltage detection portion in a state in which the voltage value of the digital voltage signal is within a predetermined voltage range; a battery as a voltage source of the measurement target analog voltage; and a control portion which, when the fault detection portion detects the fault, limits the discharging of the battery, or limits the charging of the battery, or limits the discharging and charging of the battery.