Vehicle Battery Deep Discharge Prevention Circuit

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Solution Overview

Problem

Existing solutions fail to reliably prevent deep discharge of vehicle batteries, leading to insufficient energy reserves for engine starting, especially in vehicles equipped with advanced systems that continue to draw energy even when parked, resulting in irreversible damage and starting difficulties.

Innovation Solution

A circuit arrangement that includes a first switch to isolate ignition-independent consumers from the energy store and a detection device to recognize user presence or access, allowing reconnection of these consumers to the energy store when needed, thereby preventing deep discharge and ensuring energy reserves are maintained for engine starting.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If ignition-independent consumers are continuously connected to the energy store, then convenience and functionality are improved, but deep discharge and battery damage occur

Engineering Contradiction:
Improveconvenience of ignition-independent consumersVSAvoidbattery health and energy reserve
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The detection device detects user presence or access to the vehicle in advance before the user would normally start the engine. This allows the control unit to proactively close the switch and reconnect consumers to the energy store before deep discharge occurs, preventing battery damage while maintaining convenience.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system continuously monitors for user presence or access through the detection device and provides feedback to the control unit. When user presence is detected, the control unit responds by closing the switch to reconnect consumers, creating a feedback loop that prevents deep discharge while maintaining system convenience.

Inventive Principle:
Principle #23Feedback

2Reliability

If the switch isolates consumers from the energy store, then deep discharge is prevented, but user convenience and system functionality are reduced

Engineering Contradiction:
Improvebattery protection from deep dischargeVSAvoidaccessibility of ignition-independent consumers
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The system performs preliminary detection of user presence or access before isolation would affect user convenience. By detecting user intent in advance, the control unit can maintain consumer isolation only when necessary (when no user presence is detected), thus protecting the battery while preserving user convenience when needed.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The switch state is dynamic rather than static - it transitions between open and closed positions based on real-time detection of user presence. This dynamic adjustment allows the system to optimize both battery protection and user convenience at different times, rather than being locked into a fixed isolation state.

Inventive Principle:
Principle #15Dynamics

3Difficulty of detecting and measuring

If the detection device operates while the energy store is disconnected, then user presence can be recognized, but additional energy consumption occurs

Engineering Contradiction:
Improveuser presence detection capabilityVSAvoidenergy consumption by detection device
Core Design Contradiction:
Difficulty of detecting and measuringVSUse of energy by moving object

Solution Approach 1:

The detection device performs user presence detection as a preliminary action before reconnection occurs. This allows the system to detect user intent while the switch is still open, and only then close the switch to reconnect consumers, minimizing the duration of energy consumption by the detection device while maintaining detection capability.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP2786466B1Circuit and method for avoiding deep discharges of an accumulator of a motor vehicle
Publication Date: 2016.05.25 BAYERISCHE MOTOREN WERKE AG
  • EP2786466B1 patent drawingFigure 1~2
  • EP2786466B1 patent drawingFigure 3

AI summary

The present invention relates to a circuit arrangement and a method for avoiding deep discharges of an energy store in a motor vehicle power supply system by means of ignition-independent loads connected to the energy store. For this purpose, a first switch for isolating the energy store from ignition-independent loads, an identification device for identifying a user presence or a user requirement or a user access to the vehicle and corresponding method steps are provided, wherein the identification device is designed to instruct closing of the first switch and/or output of a signal to the user in response to a user presence or a user requirement.