External Charging Current Control for Battery Overheating Prevention
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Solution Overview
Problem
Existing vehicle charging systems cannot effectively protect power storage devices from overheating during external charging, as the control device fails to accurately manage charging currents using detection values from current sensors.
Innovation Solution
A vehicle control device sets a command value for the charging current and reduces it when an integrated value exceeds a threshold, implementing a reduction process to prevent overheating, allowing for delayed reduction of charging speed and heat generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a large charging current is supplied from the system power supply to the power storage device during external charging, then the charging speed increases, but the power storage device is more likely to overheat
Solution Approach 1:
The control device dynamically adjusts the command value for charging current based on the integrated value. When the integrated value is small, a larger command value is allowed for faster charging. When the integrated value becomes large, the command value is reduced to prevent overheating. This dynamic adjustment resolves the contradiction between charging speed and overheating prevention.
Solution Approach 2:
The system changes the parameter of charging current (command value) based on the integrated value condition. By modifying the charging current parameter dynamically - allowing larger currents when integrated value is small and reducing currents when integrated value is large - the system achieves both fast charging and overheating prevention.
2Object-affected harmful factors
If the control device reduces the command value early to prevent overheating, then the power storage device is protected from overheating, but the charging speed decreases
Solution Approach 1:
The control device performs preliminary action by calculating the integrated value in advance and using it to determine when to reduce the command value. This allows the system to maintain high charging speeds for as long as possible while still preventing overheating, as the reduction is triggered only when the integrated value reaches a threshold that indicates sufficient charging progress.
3Measurement precision
If the control device uses detection value of current sensor to control charging current, then the charging current can be monitored, but the power storage device cannot be adequately protected from overheating when detection values are inaccurate
Solution Approach 1:
The control device uses the integrated value as an intermediary parameter to indirectly control the charging current. Instead of relying solely on direct current detection which may be inaccurate, the system integrates the command value over time and uses this integrated value to trigger command value reduction, providing more reliable overheating protection.
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
This solution effectively reduces heat generation in power storage devices, protecting them from overheating even when detection values are inaccurate, by gradually decreasing the charging current as the integrated value increases, thus preventing overheating.
Implementation Method 1
a large charging current can lead to overheating of the power storage device
Data Source
AI summary
A vehicle configured to perform external charging for charging an in-vehicle power storage device using electric power supplied from a system power supply outside the vehicle, wherein the vehicle includes a control device and a storage device. The control device is configured to set a command value of a charging current supplied from the system power supply to the power storage device through the charging device during the external charging, and to control the charging current by transmitting the command value to the charging device. The storage device is configured to store a program executed by the control device. The control device calculates an integrated value of the command value when the command value is larger than a threshold value. The control device is configured to execute a reduction process of reducing the command value when the integrated value is large than when the integrated value is small.