EV Charging Relay Circuit With Variable Resistance Control

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Solution Overview

Problem

Existing electric vehicles face challenges in maintaining the operation of electrical loads during battery charging, as continuous power supply from a charger is needed to prevent overcharging of the battery pack, which can disrupt the function when the battery is fully charged.

Innovation Solution

A charging management apparatus and method that regulates the resistance value of the power line connecting the battery pack to a charger, using a controller to manage relays and resistance circuits to ensure continuous power supply to the electrical load while preventing overcharging by adjusting resistance values based on voltage and current conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the charger continuously supplies power to the electrical load during battery charging, then the specific function of the electrical load is maintained, but the battery pack may be overcharged when fully charged

Engineering Contradiction:

Improvefunction maintenance of electrical loadVSAvoidovercharging of battery pack

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a charging management apparatus as an intermediary component between the charger and the battery pack. This apparatus includes a controller that detects battery charging status and regulates power flow, acting as a mediator to prevent direct continuous power supply to the battery while maintaining power supply to the electrical load through alternative pathways.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent segments the power supply pathway into multiple independent channels: one channel for charging the battery pack (controlled to prevent overcharging) and another channel for powering the electrical load (maintained continuously). This segmentation allows independent control of each function, resolving the contradiction between maintaining load function and preventing battery overcharge.

Inventive Principle:

Principle #1Segmentation

2Object-affected harmful factors

If the charger stops power supply when battery is fully charged, then overcharging is prevented, but the specific function of the electrical load cannot be maintained

Engineering Contradiction:

Improveovercharging preventionVSAvoidfunction maintenance of electrical load

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The charging management apparatus provides multi-functionality by simultaneously performing battery charging management and electrical load power supply management. The apparatus can switch between different power distribution modes: charging mode (when battery needs power) and load power mode (when battery is full), making the system universal in handling different operational requirements.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Reliability

If the resistance value of the power line is regulated during charging, then continuous power supply to electrical load is achieved while preventing battery overcharging, but the device complexity increases

Engineering Contradiction:

Improvecontinuous power supply and overcharge preventionVSAvoidcharging management apparatus structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent utilizes parameter changes, specifically adjusting the resistance value of the power line during different charging stages. The controller modifies resistance parameters dynamically: using higher resistance during charging to limit current to the battery, and switching to lower resistance configurations to maintain efficient power supply to the electrical load, thereby achieving multiple objectives through parameter modulation.

Inventive Principle:

Principle #35Parameter changes

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

Ensures continuous power supply to electrical loads in electric vehicles, maintaining their function during charging while preventing battery overcharging, thereby ensuring safe and efficient battery management.

Implementation Method 1

a resistance regulation circuit (111) including a first resistor (R1) having a first resistance value and a second resistor (R2) having a second resistance value

Methodology Applied

Scientific EffectElectrical Resistance: Electrical Resistance

Data Source

PatentUS12556018B2Charging management apparatus, charging management method, and electric vehicle

Publication Date: 2026.02.17 LG ENERGY SOLUTION LTD

AI summary

A charging management apparatus includes a main relay connected between a positive electrode terminal of a battery pack and a charging terminal of a charging connector, a current regulator connected in parallel to the main relay and including a precharge relay and a resistance regulation circuit connected in series, a battery pack voltage sensor, a battery pack current sensor, and a controller to control the main relay is into an on state and the precharge relay into an off state in response to a first switching condition while the main relay is in the off state, the resistance regulation circuit at a first resistance value and the precharge relay is in the on state, and to control the resistance regulation circuit to a second resistance value, the precharge relay into the on state and the main relay into the off state, in response to a second switching condition.