Lithium Battery Charge Control for Utility Vehicle Storage
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Solution Overview
Problem
Conventional electric vehicles with lead acid batteries face inefficiencies, including weight, shorter cycle life, and inconsistent voltage, while lithium batteries require precise charge management to prevent capacity loss and gas release when stored at high temperatures, making it labor-intensive and error-prone to adjust their state of charge for long-term storage.
Innovation Solution
A control system for lithium batteries that transitions between normal operating and storage modes, adjusting the charge level to a predefined range of 20-50% of full capacity, using electronic circuitry and user input devices to automate the process, ensuring capacity preservation and reducing gas release risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If lithium batteries are stored at high state of charge to maximize capacity availability, then battery capacity is preserved for immediate use, but the battery may lose capacity and physically expand due to gas release when stored at high temperature for long periods
Solution Approach 1:
The system performs preliminary discharge of the lithium battery before storage to reduce the state of charge to a safe level (below 50%). The control circuit automatically detects when the vehicle is in storage mode and initiates discharge through electrical loads or external discharge circuits, preventing the harmful effects of high state of charge during long-term storage while maintaining capacity availability when the vehicle is put back into service
2Reliability
If manual discharge processes are used to adjust lithium battery charge level for storage, then battery capacity is preserved, but the process is labor intensive, error prone, and iterative
Solution Approach 1:
The control circuit automatically manages the battery discharge process without requiring manual intervention. The system self-monitors the state of charge, calculates the required discharge amount, and executes discharge through available electrical loads or external discharge circuits. The process is initiated by detecting storage mode and terminates automatically when the target charge level is reached, eliminating labor-intensive manual operations
Solution Approach 2:
The control circuit continuously monitors the battery's state of charge during discharge and uses this feedback information to adjust the discharge rate and terminate the process at the optimal point. The system reads voltage or charge level data from the battery management system and compares it against target values to ensure precise charge level adjustment for storage conditions
3Productivity
If lithium batteries are charged to full saturation like lead acid batteries, then charging time is reduced and capacity is maximized, but the battery may physically expand due to gas release and sustain permanent damage
Solution Approach 1:
The system changes the charge level parameter from the conventional 100% saturation to a reduced level (below 50% state of charge) specifically for storage conditions. The control circuit detects storage mode and adjusts the charging parameter accordingly, either by limiting charge acceptance or by discharging excess charge after normal charging, thereby preventing gas release and physical expansion while maintaining efficient charging during active use
Data Source
AI summary
A technique controls charge on a lithium battery of a utility vehicle. The technique involves operating electronic circuitry of the utility vehicle in a normal operating mode in which the electronic circuitry charges the lithium battery to a normal charge level. The technique further involves, after operating the electronic circuity in the normal operating mode, transitioning the electronic circuitry from the normal operating mode to a storage mode in which the electronic circuitry is configured to set an amount of charge on the lithium battery to within a predefined storage range (or level) which is lower than the normal charge level. The technique further involves, in response to transitioning the electronic circuitry, adjusting the amount of charge on the lithium battery from an initial charge level which is outside the predefined storage range to an adjusted charge level which is within the predefined storage range.