Battery Charge Equalization via Master Control Unit
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Solution Overview
Problem
Existing battery systems in electric vehicles face challenges in evenly distributing the charge states among individual batteries, leading to inefficiencies in startup times and potential damage from high currents during system restarts.
Innovation Solution
A method and device utilizing a master control unit connected to a CAN bus to detect charge states, determine a balanced state of charge, and adjust individual battery charges via balancing currents, ensuring all batteries reach a uniform state for quick and simultaneous high-current bus engagement, with optional external termination and time-based completion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If individual batteries are connected to the high-current bus without charge equalization, then the system can start quickly, but some batteries may be damaged due to high currents
Solution Approach 1:
The master control unit performs charge state detection and equalization calculations before the system restarts. By determining the required equalization currents in advance and preparing the balancing process, the system ensures batteries are ready for high-current operation without actual equalization occurring during the critical startup moment, thus maintaining both speed and safety
2Reliability
If charge equalization is performed before system restart, then battery safety is improved, but startup time is delayed
Solution Approach 1:
The control unit calculates and determines the equalization currents and required balancing time before the system restart occurs. This preliminary determination allows the actual equalization process to be prepared in advance, enabling the system to understand what balancing is needed without necessarily executing the full equalization process before restart, thus minimizing time loss while ensuring safety
3Stability of the object's composition
If balancing current is applied to equalize charge states, then charge distribution is improved, but system complexity increases
Solution Approach 1:
The control system is segmented into individual battery management units, with each battery having its own monitoring and control capability. The master control unit coordinates these segmented units by calculating equalization currents for each battery independently based on their individual charge states, rather than requiring a complex centralized control system to manage all batteries simultaneously
Data Source
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AI summary
The invention relates to a method (200) for equalising charging states of individual batteries of a battery system, wherein the individual batteries are connected to a CAN bus, and the battery system has a master control unit that is assigned to one of the individual batteries, said method comprising the following steps: • detecting (210) a switch-off signal of a superordinate control unit with the aid of the master control unit, • detecting (220) the charging states of the individual batteries with the aid of the master control unit, • determining (230) a predefined charging state subject to a total charging state of the battery system and a number of individual batteries connected to the CAN bus with the aid of the master control unit, • determining (240) an equalising current for each individual battery subject to the predefined charging state and the charging state of the individual battery and • equalising (250) the charging states of the individual batteries with the aid of the equalising currents.