Battery Control Unit Series Switching for Charging Time
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Solution Overview
Problem
In battery systems where batteries deteriorate at different rates due to manufacturing variations and environmental factors, existing charging methods lead to prolonged charging times as batteries switch from constant current to constant voltage charging, causing inefficiencies when some batteries have not yet reached the required voltage reduction.
Innovation Solution
A battery control unit with switching units and a controller that manages the series connection of batteries, allowing all batteries to be charged with constant current until they reach a charge changing voltage, then switching to constant voltage charging for all batteries once this voltage is reached, thereby optimizing charging time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If batteries are charged using traditional CCCV method where switching from constant current to constant voltage charging is triggered by the first battery reaching charge termination voltage, then overcharging is prevented, but charging time becomes excessively long because other batteries must wait and reduce charging current prematurely
Solution Approach 1:
The charging process is segmented into two distinct phases: a constant current charging phase where all batteries charge simultaneously at maximum current, and a constant voltage charging phase where all batteries charge together at reduced voltage. This segmentation allows the system to optimize charging speed during the initial phase without risking overcharging, as the switch to voltage reduction is triggered by the first battery reaching its charge termination voltage rather than waiting for all batteries to reach it simultaneously.
Solution Approach 2:
The system performs preliminary constant current charging for all batteries simultaneously before any battery reaches its charge termination voltage. This preliminary action maximizes charging efficiency by maintaining high current flow through all batteries during the period when none of them are at risk of overcharging. The switch to constant voltage charging is prepared in advance once the first battery signals it has reached its charge termination voltage, ensuring a smooth transition that prevents overcharging while minimizing time loss.
2Productivity
If all batteries are charged with constant current until the first battery reaches charge changing voltage, then charging efficiency is maximized, but the system complexity increases due to the need for individual battery monitoring and coordinated switching
Solution Approach 1:
The system employs feedback mechanisms where each battery's voltage is continuously monitored, and when the first battery reaches its charge termination voltage, this information is fed back to the charging controller. The controller then automatically switches from constant current to constant voltage charging mode for all batteries. This feedback-based control simplifies the system architecture by using a centralized monitoring approach rather than requiring complex coordinated control of multiple independent charging circuits.
Data Source
AI summary
A battery control unit includes a plurality of battery units, a charger configured to charge a battery, a controller, and a charging controller. Each of the plurality of battery units includes a switching unit. The switching unit is configured to switch between a connected state where the battery configured to be located in the same battery unit as that of the switching unit is connected in series with the battery configured to be located in an adjacent battery unit, and a non-connected state where the battery in the same battery unit as that of the switching unit is disconnected from the series connection with the battery in the adjacent battery unit.