Battery Pack Relay State Diagnosis by Current Sensing in Parallel Packs
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Solution Overview
Problem
Conventional methods struggle to accurately diagnose whether relays in a parallel battery pack system are open or closed due to the connection characteristics of backup battery packs, which can result in a DC link voltage being charged even when one battery pack is connected, making it difficult to determine the state of other battery packs.
Innovation Solution
A battery pack diagnosis control apparatus that measures current flowing through the relays of the battery packs using a current diagnosis method, determining if the current exceeds a predetermined threshold to diagnose relay states accurately.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If voltage difference method is used to diagnose relay state, then diagnosis simplicity is maintained, but diagnosis accuracy deteriorates due to DC link voltage charging in parallel battery pack configuration
Solution Approach 1:
The patent changes the diagnostic parameter from voltage difference to current measurement. By measuring the current flowing through each battery pack instead of comparing voltage differences, the system can accurately determine relay states even in parallel configurations where DC link voltage charging occurs. This parameter change resolves the contradiction by maintaining diagnostic simplicity while eliminating the accuracy problem caused by voltage method limitations.
2Reliability
If parallel battery pack configuration is used for backup, then system reliability is improved, but diagnostic capability deteriorates due to inability to distinguish individual pack states
Solution Approach 1:
The patent applies segmentation by measuring current through each individual battery pack separately rather than measuring the combined parallel output. By isolating and measuring the current of each pack independently, the system can determine the state of individual relays while maintaining the parallel configuration for reliability. This allows the system to benefit from redundancy while achieving accurate individual pack diagnostics.
3Device complexity
If voltage-based diagnosis is used in parallel battery system, then device complexity is minimized, but measurement reliability deteriorates due to voltage equalization effects
Solution Approach 1:
The patent changes the measurement parameter from voltage to current to overcome the limitations of voltage-based diagnosis in parallel systems. Current measurement provides direct information about the state of each battery pack without being affected by voltage equalization or charging effects that occur in parallel configurations. This parameter change maintains relatively simple device complexity while significantly improving measurement reliability.
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 precise identification of faulty battery packs by measuring current flow, ensuring safe flight operations by accurately diagnosing relay states in parallel battery packs.
Implementation Method 1
measure a current flowing from the battery pack to the diagnosis circuit
Data Source
AI summary
The present disclosure relates to a battery pack diagnosis control apparatus, a battery system including the same, and a method thereof. An exemplary embodiment of the present disclosure provides a battery system including: at least one battery pack; a flight control apparatus configured to transmit at least one of a battery discharge mode command or a motor discharge command; a battery control apparatus configured to transmit a relay control command for a relay based on receiving the battery discharge mode command, and transmit a diagnosis command based on receiving the motor discharge command; and at least one battery pack control apparatus configured to control the relay based on receiving the relay control command, and diagnose a failure of the at least one battery pack by measuring a current of the at least one battery pack based on receiving the diagnosis command.