Dynamic Battery Charging Current Control via Surface Temperature Feedback
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Solution Overview
Problem
Lithium ion battery charging systems face challenges in preventing surface temperature from exceeding safe limits, leading to reduced charging capacity and prolonged charging times, especially when ambient temperatures rise.
Innovation Solution
A charging system that dynamically adjusts the charging current based on real-time surface temperature measurements, using a temperature element and a control unit to maintain the surface temperature within a target range, allowing for full charge capacity while preventing temperature exceedance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the charging current is increased to reduce charging time, then the charging speed improves, but the surface temperature of the battery exceeds safe limits
Solution Approach 1:
The charging current is dynamically adjusted based on real-time surface temperature measurements. The control unit modifies the charging current in response to temperature changes, allowing the system to operate at high current when cool and reduce current when temperature rises, thus resolving the contradiction between charging speed and temperature control
Solution Approach 2:
A temperature element continuously monitors the battery surface temperature and feeds this information back to the control unit. The control unit uses this feedback to adjust the charging current, creating a closed-loop control system that balances charging speed with temperature safety
2Temperature
If the charging current is limited to prevent temperature rise, then the surface temperature remains within safe limits, but the charging time increases
Solution Approach 1:
Rather than using a fixed limited current, the system dynamically adjusts the charging current based on actual temperature conditions. When the battery is cool, higher current is applied to reduce charging time. When temperature rises, current is reduced to maintain safety. This dynamic approach minimizes charging time while ensuring temperature remains within safe limits
3Productivity
If standard maximum charging current is applied regardless of temperature, then charging efficiency is maximized, but safety risks increase when ambient temperature is high
Solution Approach 1:
The temperature element provides continuous feedback on battery surface temperature, enabling the control unit to adjust charging current in response to actual thermal conditions. This feedback mechanism ensures that charging efficiency is maximized when safe, and safety is prioritized when temperature rises, resolving the contradiction between productivity and reliability
Solution Approach 2:
The charging current parameter is changed based on temperature conditions. The control unit modifies the charging current parameter in response to temperature variations, allowing the system to operate at maximum efficiency when cool and reduce current when hot, thus balancing charging efficiency with safety
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
Enables full charge capacity of lithium ion batteries while keeping surface temperatures within safe limits, even during varying ambient conditions, thereby optimizing charging efficiency and reducing charging time.
Implementation Method 1
a temperature element (111) that measures a surface temperature of the battery cell (103)
Implementation Method 2
a temperature element (111) that measures a surface temperature of the battery cell (103)
Data Source
AI summary
A charging system capable of charging a battery cell so that the surface temperature of the battery cell does not exceed an upper temperature limit, is provided. A battery charger is configured in a manner such that a setting current is variable during charging. The battery charger starts charging of a secondary battery with a setting voltage set to a minimum charging current value. The surface temperature of the secondary battery is measured during charging. An estimated temperature value is calculated which is a surface temperature of the secondary battery, at which the secondary battery is charged up until a charging amount corresponding to the maximum surface temperature under assumption that the charging is performed with a present charging current value. The setting current is increased when the estimated temperature value is lower than the target temperature range and is reduced when the estimated temperature value is higher than the target temperature range. When the estimated temperature value belongs to the target temperature range, a present setting current is maintained.