Battery Residual Capacity Calculation for Portable Radiation Devices
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Solution Overview
Problem
Portable radiation irradiation devices using lithium ion batteries face challenges in accurately managing residual capacity due to changing internal resistance, leading to erroneous battery state determination and potential device shutdown during high current radiation emission.
Innovation Solution
A radiation irradiation device with a residual capacity calculation part that calculates battery capacity based on current and voltage measurements at different time points, accounting for internal resistance, allowing for accurate capacity management independent of internal resistance changes and preventing device shutdown.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If terminal voltage monitoring method is used to manage battery residual capacity, then the management method is simple, but the residual capacity management becomes inaccurate when internal resistance changes
Solution Approach 1:
The patent replaces the simple terminal voltage monitoring method with an electrochemical model-based calculation method. The control unit calculates residual capacity by integrating current over time and correcting for internal resistance effects, substituting the direct voltage measurement approach with a more sophisticated electrochemical model that accounts for internal resistance changes during battery discharge.
Solution Approach 2:
The patent changes from monitoring a single parameter (terminal voltage) to monitoring multiple parameters (terminal voltage, current, and internal resistance). The control unit measures terminal voltage and current, calculates internal resistance based on these measurements, and uses all three parameters to accurately determine residual capacity, thereby resolving the inaccuracy caused by internal resistance changes.
2Power
If high current flows during radiation emission, then the radiation source can operate effectively, but the terminal voltage drops significantly causing erroneous battery state determination
Solution Approach 1:
The patent introduces internal resistance calculation as an intermediary parameter between current measurement and residual capacity determination. The control unit calculates internal resistance based on terminal voltage and current measurements, then uses this intermediary value to correct the residual capacity calculation, preventing erroneous battery state determination during high current operation.
Solution Approach 2:
The patent implements a feedback mechanism where the control unit continuously monitors terminal voltage and current, calculates internal resistance based on these measurements, and uses the calculated internal resistance to continuously update and correct the residual capacity value. This closed-loop feedback ensures accurate battery state determination even during high current radiation emission.
Data Source
AI summary
The invention provides a radiation irradiation device that can appropriately manage the residual capacity of a battery without being influenced by the internal resistance of the battery. The radiation irradiation device includes a radiation generating part that generates radiation; a battery part that supplies electric power to the radiation generating part; and a residual capacity calculation part that calculates the residual capacity of the battery part. The residual capacity calculation part calculates the residual capacity of the battery part on the basis of a current flowing into the battery part, an internal resistance of the battery part, and a voltage of the battery part.