Battery Charging Voltage Threshold Adjustment Under Load
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Solution Overview
Problem
Existing battery charging methods struggle to accurately determine full charge voltage when a battery is connected to a load, leading to measurement errors and inefficiencies in charging secondary batteries like lithium-ion batteries.
Innovation Solution
An apparatus and method that utilize an early charging mode followed by a late charging mode, where the battery is charged with a preset cut-off voltage and phased decrement of charge power, allowing the battery to reach a higher full charge voltage efficiently, even when connected to a load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If voltage-based charging is used for secondary batteries, then charging simplicity is maintained, but measurement accuracy deteriorates when the battery is connected to a load
Solution Approach 1:
The patent applies preliminary action by performing a rest period before voltage measurement. The battery is disconnected from the load for a predetermined time (e.g., 5 minutes) to allow voltage stabilization, ensuring accurate full charge detection without requiring complex measurement systems during active charging operations
2Measurement precision
If SOC-based charging algorithm is used to charge batteries connected to loads, then charging accuracy improves, but reliability deteriorates due to accumulation of measurement errors
Solution Approach 1:
The patent implements feedback by continuously monitoring voltage during charging and comparing it against a dynamic threshold that accounts for charge current. When voltage reaches the threshold, charging is adjusted, creating a closed-loop control system that prevents overcharging while ensuring full charge, thereby maintaining reliability across multiple charging cycles
Solution Approach 2:
The patent changes parameters by using a voltage threshold that varies based on charge current magnitude. Instead of a fixed voltage cutoff, the threshold is adjusted according to the relationship between voltage and charge current, allowing accurate full charge detection under different loading conditions without accumulating errors
3Ease of operation
If voltage threshold is set to open circuit voltage for full charge detection, then measurement simplicity is maintained, but productivity deteriorates due to inability to charge batteries under load
Solution Approach 1:
The patent changes the voltage threshold parameter from a fixed open circuit voltage value to a dynamic value that depends on charge current. The threshold voltage is calculated as a function of charge current, enabling accurate full charge detection whether the battery is under load or not, thus maintaining productivity across different operating conditions
Data Source
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AI summary
Disclosed is an apparatus and method for charging a battery in a simple and efficient way. The apparatus for charging a battery includes a voltage measuring unit for measuring a voltage of a battery, a control unit for outputting a charge control signal corresponding to an early charging mode in which the battery is charged until a voltage of the battery rises to a preset cut-off voltage (Vc) and a charge control signal corresponding to a late charging mode in which the battery is charged while lowering a charge power in phases, and a charging unit for providing a charge power corresponding to the charge control signal to the battery, wherein a point of lowering the charge power in phases is associated with a point at which the voltage of the battery reaches the cut-off voltage again by the lowered charge power. Therefore, a voltage level reached at full charge of a battery may be raised in a simple and efficient way.