Power Control Apparatus Voltage Deviation Detection
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Solution Overview
Problem
In battery packs with multiple single cell groups connected in parallel, voltage differences between groups increase excessively when a main contactor becomes stuck open or a single cell group disconnects, leading to potential overheating and sudden vehicle shutdown due to excessive current flow through precharge resistors or fuses.
Innovation Solution
A power control apparatus with a voltage detection unit, a voltage deviation calculation unit, a comparator, and a cutoff detection unit that monitors voltage deviations between batteries, notifies the driver of abnormalities, and can stop the load when voltage deviations exceed predetermined thresholds to prevent overheating and sudden shutdowns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a main contactor becomes stuck open or a single cell group disconnects, then voltage difference between single cell groups increases excessively, but this leads to overheating of precharge resistors or fuses and potential sudden vehicle shutdown
Solution Approach 1:
The control device performs preliminary detection of voltage deviations between parallel-connected battery units before excessive current can flow through precharge resistors. When a voltage deviation exceeding the threshold is detected, the control device preemptively controls the contactor to disconnect the battery unit, preventing the condition that would lead to resistor overheating and potential vehicle shutdown.
Solution Approach 2:
The control device continuously monitors voltage deviations between battery units and uses this feedback to make real-time control decisions. When the voltage deviation feedback indicates an abnormal condition, the control device adjusts the contactor state to prevent overheating, creating a closed-loop control system that actively prevents the technical contradiction from manifesting.
2Reliability
If voltage deviation detection and control is implemented, then overheating is prevented, but device complexity increases
Solution Approach 1:
The control device integrates multiple functions into a single control unit: voltage detection, voltage deviation calculation, threshold comparison, and contactor control. This multi-functional approach prevents the need for separate dedicated components for each function, thereby limiting the increase in device complexity while maintaining the ability to prevent overheating and ensure reliable vehicle operation.
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
The apparatus effectively detects and prevents excessive voltage deviations, notifies drivers of abnormalities, and stops the load to prevent overheating and sudden vehicle shutdowns, distinguishing between self-discharge and abnormal voltage deviations, and reducing the risk of precharge resistor overheating.
Implementation Method 1
a voltage detection unit which detects a voltage of each battery
Implementation Method 2
excessive current flows between the single cell groups via the precharge resistors
Implementation Method 3
the precharge resistor or the fuse provided in the single cell group is overheated to cause an abnormality
Data Source
AI summary
A power control apparatus is mounted on an electrically driven vehicle which includes an electrical storage device configured by connecting a plurality of batteries in parallel, a voltage detection unit which detects a voltage of each battery, and a load, and the power control apparatus includes, a voltage deviation calculation unit which is connected to the electrical storage device, and calculates voltage deviation between the plurality of batteries based on the voltage detected by each voltage detection unit at the time of driving the load which is driven by power supply from the electrical storage device, a comparator which compares the voltage deviation calculated by the voltage deviation calculation unit and a first predetermined threshold, and a cutoff detection unit which detects a presence or absence of the battery, which comes into a cutoff state in the electrical storage device, when the voltage deviation is equal to or more than the first threshold in a comparison result by the comparator.