Battery Connection Detection Circuit for Accurate In-Position Sensing
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Solution Overview
Problem
Existing battery management systems struggle to accurately determine the connection status of lithium batteries due to overlapping voltage ranges for charging and discharging, making it difficult to distinguish between islanding states and normal connections.
Innovation Solution
A battery connection status detection circuit is implemented, comprising a first and second switch unit, a discharge unit, a sampling unit, and a controller, which controls the switch units to discharge the energy storage unit and analyze voltage changes at its terminals to differentiate between connected and disconnected states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If voltage measurement is used to detect battery connection status, then the detection method is simple, but the detection accuracy is insufficient due to overlapping voltage ranges
Solution Approach 1:
The detection method is segmented into multiple stages: first determining battery type (primary/secondary), then based on that result, selectively applying different detection methods (voltage measurement for primary batteries, impedance measurement for secondary batteries). This segmentation allows each detection stage to be optimized for its specific purpose, resolving the contradiction between simplicity and accuracy.
Solution Approach 2:
The patent changes the detection parameter based on battery type: using voltage (a simple parameter) for primary batteries where it provides sufficient discrimination, and switching to impedance (a more precise parameter) for secondary batteries where voltage alone is insufficient. This dynamic parameter selection resolves the contradiction by adapting the measurement approach to the specific detection needs.
2Measurement precision
If impedance measurement is used to distinguish battery states, then the detection accuracy is improved, but the device complexity and power consumption increase
Solution Approach 1:
The patent performs a preliminary voltage measurement to determine battery type before proceeding to impedance measurement. This preliminary action filters out primary batteries that don't require complex impedance detection, ensuring that the more complex and power-intensive impedance measurement is only applied when necessary (for secondary batteries), thus balancing accuracy needs with device complexity and power consumption.
3Reliability
If continuous monitoring is implemented to ensure accurate detection, then the reliability is improved, but the power consumption increases
Solution Approach 1:
Instead of continuous monitoring, the patent implements periodic detection with a predetermined period. The controller performs detection at intervals, measuring voltage and impedance only when needed, rather than continuously. This periodic approach maintains detection reliability by regularly checking battery status while significantly reducing power consumption compared to continuous monitoring.
Data Source
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AI summary
This application discloses a battery connection status detection circuit and method, a battery, a device, and a system, and relates to the field of power electronics technologies. The detection circuit is disposed in a battery. The battery includes a cell pack. The detection circuit includes a first switch unit, a second switch unit, a discharge unit, a sampling unit, an energy storage unit, and a controller. A first terminal of the first switch unit is connected to a first terminal of the cell pack. A second terminal of the first switch unit is connected to a second terminal of the cell pack after being connected in series to the energy storage unit. The second switch unit is connected in parallel to the energy storage unit after being connected in series to the discharge unit. The discharge unit discharges the energy storage unit. The sampling unit is connected in parallel to the energy storage unit. The sampling unit sends an obtained sampling signal to the controller. The controller is configured to control the first switch unit and the second switch unit, and determine, based on the obtained sampling signal, a connection status of the battery. The detection circuit can detect the connection status of the battery.