Solid-State Battery Protection Switching for Fast Fault Isolation

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Solution Overview

Problem

Existing battery protection units face challenges in quickly disconnecting a line during fault currents, leading to potential damage and requiring manual fuse replacement, as mechanical switches and fuses take time to respond effectively.

Innovation Solution

A battery protection unit incorporating a solid-state circuit breaker with semiconductor switches and a rack battery management system that controls gate drivers to rapidly disconnect the line and automatically reconnect it when current conditions are restored, using a GMR sensor for overcurrent detection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a molded case circuit breaker (MCCB) and fuse are used for overcurrent protection, then the battery system is protected from fault currents, but the response time is too slow and manual fuse replacement is required

Engineering Contradiction:

Improveprotection reliabilityVSAvoidresponse time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent replaces the mechanical MCCB with a solid-state circuit breaker using semiconductor switches (MOSFETs or IGBTs) that can detect overcurrent and disconnect the circuit electronically within microseconds, eliminating the slow mechanical operation of traditional breakers and the need for manual fuse replacement

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The solid-state circuit breaker automatically detects fault conditions through current sensors and triggers protective action without human intervention, and can automatically reset after fault clearance, eliminating the need for manual fuse replacement and system restart

Inventive Principle:

Principle #25Self-service

2Reliability

If a fuse is used to protect against overcurrent, then the battery system is protected, but the line remains connected until the fuse is completely blown causing potential damage

Engineering Contradiction:

Improveprotection reliabilityVSAvoidfault current exposure

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The solid-state circuit breaker continuously monitors current and triggers protective disconnection before the fuse would completely blow, limiting fault current exposure time to microseconds and preventing damage to batteries and equipment

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The semiconductor-based solid-state breaker provides controlled electronic interruption of fault current, replacing the uncontrolled thermal-magnetic blowing action of fuses that exposes the system to prolonged harmful currents

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If manual fuse replacement is required after fault current, then protection is provided, but system downtime increases and operation complexity increases

Engineering Contradiction:

Improveprotection functionVSAvoidoperation complexity

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The solid-state circuit breaker automatically resets after fault clearance by the control system, restoring normal operation without requiring manual fuse replacement or system restart, thereby simplifying operation and reducing downtime

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The electronic solid-state breaker with automated control replaces the manual fuse replacement process, allowing the system to self-restore after faults through electronic control rather than mechanical intervention

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 solution significantly reduces the time to disconnect the line during fault currents, preventing damage and allowing automatic reconnection without manual intervention, enhancing safety and efficiency.

Implementation Method 1

a GMR sensor for overcurrent detection

Methodology Applied

Scientific EffectGiant magnetoresistance (GMR): Magnetoresistance

Implementation Method 2

a semiconductor switch electrically connecting or insulating between the battery system and the line according to a gate voltage applied to a gate terminal thereof

Methodology Applied

Scientific EffectSemiconductor switching:

Data Source

PatentUS20240178656A1Battery protection unit and control method for battery protection unit

Publication Date: 2024.05.30 LS ELECTRIC CO LTD

AI summary

The present disclosure comprises: a solid-state circuit breaker, which is arranged between a battery system and a line and includes a semiconductor switch for providing an electrical connection or insulation between the battery system and the line according to the voltage applied to a gate terminal; an interrupter switch for providing a physical connection or separation between the solid-state circuit breaker and the line; and a rack battery management system which controls a gate driver applying the gate voltage, so as to provide insulation between the battery system and the line according to the result of sensing a current flowing between the battery system and the line, and which controls the interrupter switch to physically separate the solid-state circuit breaker from the line.