Battery Current Protection via Segmented Transistor Control

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Solution Overview

Problem

Existing DC/DC converter systems lack control over charging current to batteries and protection against excessive discharge current, particularly in scenarios like electric vehicles where a shorted load can occur, leading to potential battery damage.

Innovation Solution

A system with control circuitry and transistors that detect current and adjust charging and discharge currents, disconnecting the load if excessive discharge current is detected and maintaining charging current at a set level, ensuring battery protection and efficient power distribution between the DC/DC converter, battery, and load.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the DC/DC converter current limit is configured to protect the converter, then the converter is protected, but the charging current to the battery is not controlled and discharge current cannot be limited in shorted load conditions

Engineering Contradiction:
Improveconverter protectionVSAvoidexcessive battery charging and discharge current
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces intermediate control elements (switches or controllable components) in both the battery charging path and discharge path. These intermediaries allow independent control of battery charging current separate from the DC/DC converter current limit, and enable limitation of discharge current even in shorted load conditions. The intermediaries act as mediators between the converter output and the battery, providing the necessary current control without affecting the converter protection function.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If the battery is directly connected to the DC/DC converter, then the system is simple, but the battery cannot be independently protected from excessive charging or discharge current

Engineering Contradiction:
Improvesystem simplicityVSAvoidbattery current protection
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent segments the direct connection between DC/DC converter and battery into controlled paths with separate switches or controllable components for charging and discharge. This segmentation adds minimal complexity while enabling independent battery current protection, as each path can be independently controlled to prevent excessive charging or discharge current without requiring a complete system redesign.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP2448083B1Power topology with battery charging and discharge current protection capabilities
Publication Date: 2019.06.26 O2 MICRO INC
  • EP2448083B1 patent drawingFigure 1
  • EP2448083B1 patent drawingFigure 2
  • EP2448083B1 patent drawingFigure 3

AI summary

Generally, a system includes a control circuitry configured to detect a current wherein the detected current is one of a battery discharge current or a battery charging current; a first transistor configured to disconnect a load from at least one of a battery and a DC/DC converter if the battery discharge current exceeds a maximum battery discharge current setting; and a second transistor configured to adjust the charging current to maintain the charging current at or near a charge current setting.