Battery Device Overcurrent Detection Accuracy
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Solution Overview
Problem
Existing battery devices face challenges in achieving accurate overcurrent detection due to manufacturing variations in field effect transistors, leading to increased costs and reduced safety when trying to select only four transistors with desired ON resistances.
Innovation Solution
The battery device employs a first charge/discharge control device monitoring current with a voltage across its switch and a second device using a current sensing resistor, with field effect transistors selected based on desired ON resistance values, allowing for accurate current sensing while preventing increased manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If field effect transistors are selected based on desired ON resistance values to achieve accurate overcurrent detection, then measurement precision is improved, but manufacturing cost increases
Solution Approach 1:
The invention divides the charge/discharge control function into two separate devices: a first charge/discharge control device that monitors current using voltage across the charge/discharge control switch (requiring selected transistors with desired ON resistance), and a second charge/discharge control device that monitors current using a current sensing resistor (not requiring transistor selection). This segmentation allows accurate overcurrent detection while reducing manufacturing costs by limiting transistor selection requirements to only one of the two devices.
2Reliability
If two charge/discharge control devices are provided to enhance safety, then reliability is improved, but device complexity increases
Solution Approach 1:
The invention merges the functions of two charge/discharge control devices into a single integrated control circuit. The first and second charge/discharge control devices are combined to share common components including the charge/discharge control switch, current sensing resistor, and control circuitry, while maintaining redundant monitoring paths for enhanced safety. This merging reduces device complexity while preserving the reliability benefits of dual control.
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 configuration enhances the accuracy of overcurrent detection while maintaining low manufacturing costs and ensuring safety by utilizing field effect transistors with specific ON resistance values and a highly accurate current sensing resistor.
Implementation Method 1
a second charge/discharge control device which is configured to monitor the charge/discharge current with a voltage generated across both ends of a current sensing resistor
Data Source
AI summary
Provided is a battery device having high overcurrent detection current accuracy that suppresses increases in a resistance value of a charge/discharge path and in a manufacturing cost. A first charge/discharge control device is configured to monitor a charge/discharge current with a voltage generated across both ends of a charge/discharge control switch, and a second charge/discharge control device is configured to monitor the charge/discharge current with a voltage generated across both ends of a current sensing resistor. A field effect transistor forming the charge/discharge control switch is selected based on a desired ON resistance value. The charge/discharge control switch of the first charge/discharge control device includes a field effect transistor having the desired ON resistance value, and a charge/discharge control switch of the second charge/discharge control device includes a field effect transistor having an ON resistance value other than the desired ON resistance value.