Charging Apparatus Current Control for Noise Reduction
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Solution Overview
Problem
Existing lithium-ion battery charging methods face challenges in accurately switching from constant-current to constant-voltage charging, leading to deviations in charge amount and increased noise levels, which affect battery voltage and prolong charging time.
Innovation Solution
A charging apparatus with a microcomputer-controlled charging circuit that adjusts the charging current using a quadratic or linear curve-based approach, reducing the current when the battery voltage approaches the desired constant-voltage threshold, thereby minimizing noise and ensuring accurate voltage detection for seamless transition to constant-voltage charging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the current value of the charging current is increased to reduce charging time, then the charging speed is improved, but the noise level such as ripple contained in the charging current is raised
Solution Approach 1:
The charging current is dynamically adjusted based on the battery voltage state. During constant-current charging, the current is maintained at a high value for fast charging. When the battery voltage approaches the threshold voltage, the current is smoothly reduced according to a predetermined curve (linear or quadratic) to minimize noise and ripple, enabling accurate detection of the constant-voltage charging start point.
2Loss of time
If the current value of the charging current is increased, then the charging time is reduced, but the battery voltage is affected by noise due to internal resistance
Solution Approach 1:
Before transitioning to constant-voltage charging, the charging current is preliminarily reduced according to a predetermined curve when the battery voltage approaches the threshold voltage. This preliminary action minimizes noise and ripple in advance, ensuring that the battery voltage remains stable and the start point of constant-voltage charging can be accurately detected without noise interference.
3Device complexity
If the voltage when switching from constant-current to constant-voltage charging is deviated from the desired voltage, then the charging process is simplified, but the charge amount of the lithium-ion battery is deviated from the desired value
Solution Approach 1:
The charging control system continuously monitors the battery voltage during constant-current charging. When the battery voltage approaches the threshold voltage, the system provides feedback to reduce the charging current according to a predetermined curve. This feedback mechanism ensures that the battery voltage reaches the desired constant-voltage threshold accurately, enabling precise control of the charge amount while maintaining a relatively simple charging control structure.
Data Source
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AI summary
A charging apparatus includes: a charging circuit (31) configured to charge a secondary battery (15); and a control circuit (32) configured to control an operation of the charging circuit (31), the control circuit (32) including a control unit configured to control the charging circuit (31) so that the secondary battery (15) is charged with a constant current until a time when a battery voltage of the secondary battery (15) goes to a first voltage, control the charging circuit (31) so that the secondary battery (15) is charged with a current smaller than the constant current when the battery voltage goes to the first voltage, and control the charging circuit (31) so that the secondary battery (15) is charged with a constant voltage when the battery voltage goes to a second voltage higher than the first voltage.