Battery Protection Circuit for Real-Time Micro Short Detection

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Solution Overview

Problem

Existing secondary battery protection circuits fail to detect micro short circuits in real time, leading to potential safety hazards such as overheating and fires, especially in lithium-ion batteries used in portable devices and electric vehicles, due to limitations in voltage range detection and high-frequency charging conditions.

Innovation Solution

A secondary battery protection circuit utilizing memory circuits with transistors made from oxide semiconductors to retain voltage values and detect anomalies, including micro short circuits, by comparing voltage values and triggering a power-off switch when anomalies are detected, with the ability to display warning messages to users.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional protection circuits are used for secondary batteries, then basic overcharge and overdischarge protection is provided, but micro short circuits cannot be detected in real time leading to safety hazards

Engineering Contradiction:

Improvesafety of secondary batteryVSAvoiddetection of micro short circuit

Core Design Contradiction:

ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

The protection circuit performs preliminary detection of micro short circuits by continuously monitoring voltage variations before they develop into serious safety hazards. The circuit detects minute voltage changes that indicate micro short circuit conditions and triggers protective actions in advance, preventing overheating and fires before they occur.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The invention replaces conventional mechanical or simple electronic detection methods with a sophisticated protection circuit that uses transistor-based voltage comparison mechanisms. The circuit employs transistors to amplify and compare voltage signals, enabling detection of micro short circuits through electrical field variations rather than mechanical means.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Device complexity

If voltage detection range is limited in protection circuits, then circuit complexity is reduced, but micro short circuits occurring within normal voltage range cannot be detected

Engineering Contradiction:

Improvestructure of protection circuitVSAvoidvoltage detection precision

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The protection circuit changes the detection parameter from absolute voltage level to voltage variation rate. By monitoring how quickly voltage changes rather than just the voltage magnitude, the circuit can detect micro short circuits occurring within the normal operating voltage range. This parameter transformation enables detection without expanding the voltage detection range or significantly increasing circuit complexity.

Inventive Principle:

Principle #35Parameter changes

3Productivity

If fast charging is performed on secondary batteries, then charging speed is improved, but micro short circuits occur more frequently due to high-frequency charging conditions

Engineering Contradiction:

Improvecharging speedVSAvoidgeneration of micro short circuit

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The protection circuit implements feedback monitoring specifically tuned to detect the voltage variations characteristic of micro short circuits that occur during fast charging. The circuit continuously samples voltage at high frequency during charging operations and provides immediate feedback when micro short circuit conditions are detected, enabling real-time protection during high-speed charging operations.

Inventive Principle:

Principle #23Feedback

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

Enables real-time detection of micro short circuits, preventing accidents and extending battery life by interrupting output and providing user warnings, while reducing power consumption and enhancing safety through accurate anomaly detection.

Implementation Method 1

a first transistor including an oxide semiconductor and retaining a voltage value of the secondary battery in an analog manner

Methodology Applied

Scientific EffectElectrical charge retention: Capacitance

Data Source

PatentUS11990778B2Secondary battery protection circuit and secondary battery anomaly detection system

Publication Date: 2024.05.21 SEMICON ENERGY LAB CO LTD

AI summary

Safety is secured in such a manner that an anomaly of a secondary battery is detected with a protection circuit, for example, a phenomenon that lowers the safety of a secondary battery, particularly a micro short circuit, is detected early, and users are warned or the use of the secondary battery is stopped. A secondary battery protection circuit includes a first memory circuit electrically connected to a secondary battery, a comparison circuit electrically connected to the first memory circuit, a second memory circuit electrically connected to the comparison circuit, and a power-off switch electrically connected to the second memory circuit. The power-off switch is electrically connected to the secondary battery, and the first memory circuit includes a first transistor including an oxide semiconductor and retains a voltage value of the secondary battery in an analog manner.