Charge Voltage Control for Series Energy Storage Devices
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Solution Overview
Problem
In energy storage systems with multiple devices connected in series, differences in initial capacity and degradation lead to variations in charge amounts, potentially causing overvoltage in some devices, which existing techniques struggle to manage effectively, especially in batteries with sudden voltage increases near full charge state.
Innovation Solution
An energy storage device management device with a controller that decides charge voltage based on the difference in charge amount or voltage difference between devices, using stored voltage decision data to set optimal charge voltages and perform equalization processing to prevent overvoltage, even in batteries like iron-phosphate lithium ion batteries with sudden voltage increases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a charge voltage is set low to suppress overvoltage in energy storage devices with large charge amounts, then overvoltage is suppressed, but charge amount and charge efficiency are lowered
Solution Approach 1:
The charge voltage is not fixed but dynamically adjusted based on the difference in charge amounts between energy storage devices. The controller decides the charge voltage according to real-time charge amount differences, making the voltage adaptive to the actual state of each device, thereby preventing overvoltage while maximizing charge efficiency.
Solution Approach 2:
The charge voltage parameter is changed based on the charge amount difference parameter. When the difference in charge amounts between devices exceeds a threshold, the charge voltage is reduced; when the difference is within the threshold, a higher charge voltage is applied. This parameter adjustment resolves the contradiction between overvoltage suppression and charge efficiency.
2Reliability
If equalization control or voltage control is performed to suppress overvoltage, then overvoltage is suppressed, but additional control devices are required
Solution Approach 1:
The controller performs multiple functions: it monitors charge amounts, calculates charge amount differences, decides charge voltages based on these differences, and controls the charging process. By integrating these functions into a single controller, the patent avoids the need for separate equalization control devices while achieving overvoltage suppression.
Solution Approach 2:
The voltage control function is merged with the charge amount monitoring function in a single controller. The controller combines information about charge amounts and voltage states to make integrated control decisions, eliminating the need for separate control devices and reducing system complexity.
3Reliability
If equalization control or voltage control is performed to suppress overvoltage, then overvoltage is suppressed, but charge time increases due to control processing
Solution Approach 1:
The controller calculates the charge amount difference and decides the appropriate charge voltage in advance during the charging process. By proactively adjusting the voltage based on predicted charge amount differences rather than reactively responding to overvoltage conditions, the system prevents overvoltage without requiring time-consuming control adjustments during charging.
Solution Approach 2:
The controller continuously monitors charge amounts and uses this feedback to adjust the charge voltage in real-time. This closed-loop control ensures that the charge voltage is optimally adjusted based on actual charging progress, suppressing overvoltage while minimizing charge time extension.
Data Source
AI summary
Provided is an energy storage device management device which includes a controller configured to decide a charge voltage to be applied to a plurality of energy storage devices connected in series, wherein the controller is configured to perform deciding the charge voltage based on a difference in charge amount or a voltage difference between the energy storage devices.