Ambulatory Infusion Device Dynamic Battery Testing
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Solution Overview
Problem
Ambulatory infusion devices face challenges in efficiently testing energy storage, leading to potential device failure without user alert, due to power consumption during testing and rapid battery voltage drops, which can result in adverse effects.
Innovation Solution
The testing unit varies testing frequency and stress based on the energy storage's capability to power the device, using control variables like terminal voltage and internal resistance, to minimize power consumption and detect battery depletion effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If testing is carried out repeatedly with a fixed time interval to ensure device operation, then reliability of device operation is improved, but power consumption increases reducing remaining usage time of energy storage
Solution Approach 1:
The testing frequency is made dynamic rather than fixed. The controller adjusts the time interval between successive tests based on the measured terminal voltage. When terminal voltage is above the alerting threshold, tests are performed at longer intervals. When terminal voltage approaches the threshold, the interval is reduced to provide earlier warning, thus optimizing the balance between reliability and power consumption throughout the battery lifecycle.
Solution Approach 2:
The testing parameters are changed based on the state of the energy storage. The testing frequency is adjusted as a function of the terminal voltage parameter. This allows the system to perform adequate testing early in the battery life when voltage is stable, and increase testing frequency only when voltage approaches critical levels, reducing unnecessary power consumption during periods when the battery is still healthy.
2Reliability
If testing is carried out frequently to detect battery depletion early, then reliability is improved, but power consumption increases and may cause terminal voltage to drop below alerting threshold
Solution Approach 1:
The testing frequency parameter is changed dynamically based on the measured terminal voltage. The controller calculates the time interval for successive tests as a function of the current terminal voltage and a predetermined voltage slope. When voltage is high and stable, intervals are long. When voltage approaches the alerting threshold or the slope indicates rapid depletion, intervals are shortened. This adaptive parameter adjustment ensures timely detection while minimizing energy loss during testing.
3Ease of operation
If fixed testing interval is used to simplify operation, then ease of operation is improved, but ability to detect rapid voltage drop is reduced
Solution Approach 1:
The testing schedule transitions from a fixed interval to a dynamic interval based on battery state. The controller continuously monitors terminal voltage and adjusts the time interval between tests accordingly. This dynamic approach maintains simplicity of operation (automatic adjustment by controller) while significantly improving the ability to detect rapid voltage drops, as the system automatically increases testing frequency when voltage degradation is detected.
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
This approach reduces unnecessary power consumption and ensures timely detection of battery depletion, preventing device failure and adverse effects by adjusting testing intervals and stress according to the energy storage's capability.
Implementation Method 1
the terminal voltage is the voltage that can be measured at the battery terminals under normal operational conditions
Implementation Method 2
the internal resistance increases. Both effects reduce the terminal voltage if current is drawn. These effects are illustrated in Figure 9, showing an exemplary off-circuit voltage U0 curve 600 and the corresponding internal resistance Ri curve 605
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
Disclosed are ambulatory infusion devices, including: (a) an energy storage (100) for storing electrical energy required for powering the device, the energy storage (100) serving as primary power source of the ambulatory device (10) and being successively depleted during application, (b) a dosing unit with an electrically powered actuator and an electronic controller, the controller controlling operation of the actuator, (c) a testing unit (110) for testing the energy storage (100), the testing unit being designed to repeatedly carry out a test during operation of the device, the test including determining a control variable, the control variable being indicative of a capability of the energy storage (100) for further powering the device (10). In accordance with the invention, the testing unit (110) is configured to vary the testing of the energy storage in dependence of the control variable. Disclosed are further corresponding methods for testing an energy storage of an ambulatory infusion device.