EV Charging Control Device Estimating Time via Segmented Power
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Solution Overview
Problem
Existing charging systems for electric storage devices in vehicles face inaccuracies in estimating charging time, leading to potential shortages or overcharging, which can result in degradation of the storage device due to temperature and state-of-charge dependencies.
Innovation Solution
A charging apparatus that includes an electric power supply device and a control device, which adjusts charging power based on the temperature and state-of-charge of the electric storage device, estimating different charging regions and times to accurately determine the total charging completion time and set a suitable start time for charging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If charging current is restricted to account for temperature dependence of internal resistance, then charging status estimation accuracy is improved, but charging time increases
Solution Approach 1:
The charging process is divided into multiple stages with different charging currents. The control device determines whether to apply charging current restriction based on the battery's temperature and charging status, switching between restricted and unrestricted charging modes to optimize both accuracy and time.
Solution Approach 2:
The charging current is dynamically adjusted based on real-time temperature and charging status measurements. The system transitions from static charging current restriction to dynamic adjustment, optimizing charging efficiency at different stages while maintaining safety.
2Loss of time
If charging is completed earlier than scheduled, then charging time is reduced, but the electric storage device is kept in high SOC condition for long period causing degradation
Solution Approach 1:
The control device continuously monitors battery temperature and charging status, using this feedback to determine the appropriate charging current. This closed-loop control prevents overcharging and ensures the battery is not kept in high SOC condition unnecessarily, extending device life.
3Productivity
If charging current is increased to reduce charging time, then charging speed is improved, but charging status estimation accuracy deteriorates
Solution Approach 1:
The charging process is segmented into stages: initial charging with restricted current for accurate SOC estimation, and subsequent charging with higher current for speed. This segmentation allows the system to achieve both accuracy and speed at appropriate times.
Solution Approach 2:
The charging current parameter is changed based on battery conditions. The system starts with lower current for accurate measurement and estimation, then increases current when the battery is ready, optimizing both estimation accuracy and charging speed.
Data Source
AI summary
A charging apparatus includes an electric power supply device and a control device. The control device that estimates a first region in which first charging power is supplied from the electric power supply device to a electric storage device; estimates a second region, in which second charging power that is smaller than the first charging power is supplied from the electric power supply device to the electric storage device, based on temperature of the electric storage device and a state-of-charge of the electric storage; estimates a first charging time that corresponds to the first region; estimates a second charging time that corresponds to the second region; estimates a total charging time by using the first charging time and the second charging time; obtains a charging completion time; and sets a charging start time based on the charging completion time and the total charging time.