Auxiliary Battery Equalization Before Parallel Battery Pack Connection
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Solution Overview
Problem
Voltage and capacity deviations among battery packs connected in parallel can lead to overcurrents and potential ignition due to leakage currents, posing safety risks.
Innovation Solution
A battery system with an auxiliary battery and bidirectional DC-DC converters and relays adjusts voltages by discharging high-voltage packs and charging low-voltage packs before parallel connection, using a main control circuit to manage the process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If multiple battery packs are connected in parallel to increase capacity, then the total energy storage increases, but voltage and capacity deviations cause overcurrent and safety hazards
Solution Approach 1:
The patent applies preliminary action by equalizing the voltage of all battery packs before connecting them in parallel. The control unit detects voltage differences and performs equalization charging or discharging in advance, ensuring that all packs have matched voltages before parallel connection, thereby preventing overcurrent and safety hazards while maintaining high energy storage capacity
2Adaptability or versatility
If battery packs with different voltages are connected in parallel, then system flexibility increases, but overcurrent is generated due to voltage deviation
Solution Approach 1:
The control unit performs preliminary voltage equalization by detecting voltage differences among battery packs and conducting equalization charging or discharging before parallel connection, thereby eliminating the voltage deviation that would otherwise cause overcurrent while preserving system flexibility
3Reliability
If leakage current occurs in a battery pack, then the affected cell experiences current blow, but ignition and dangerous situations may result
Solution Approach 1:
The control unit performs preliminary detection of leakage currents and voltage abnormalities before parallel connection. When leakage is detected, the system performs equalization operations or isolates the affected battery pack in advance, preventing current blow and ignition risks before they can occur
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
Prevents overcurrents and reduces voltage differences, enhancing safety and power efficiency by stabilizing battery voltages before parallel connection, thus preventing ignition and optimizing power distribution.
Implementation Method 1
a bidirectional DC-DC converter including first and second ends connected to a positive electrode and a negative electrode of the auxiliary battery
Data Source
AI summary
A battery system includes: at least two battery packs; a plurality of first relays, each first relay being connected to a respective one of the at least two battery packs; and an auxiliary battery, a first battery pack among the at least two battery packs with a highest voltage is discharged to the auxiliary battery through the first relay connected to the first battery pack so that a voltage of the first battery pack approaches a voltage of another battery pack, a second battery pack with a lowest voltage is charged by the auxiliary battery through the first relay connected to the second battery pack so that the voltage of the second battery pack may approach the voltage of the another battery pack, and the at least two battery packs are connected in parallel.