Battery Self-Discharge Control for Safe Storage Voltage

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Solution Overview

Problem

Battery assemblies used in movable objects like UAVs can suffer from damage, such as swelling or leaking, when charged but left unused for extended periods due to high chemical activity, leading to reduced battery life and safety hazards.

Innovation Solution

A battery management system initiates a controlled self-discharge of the battery assembly when it is not in use for a threshold time, terminating the discharge when the battery is in use or reaches a safe storage voltage, using a self-discharging circuit with a resistor and control switch to manage storage voltage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of stationary object

If the battery assembly is charged and stored for a long term, then the battery capacity is maintained for future use, but the battery may swell or leak due to high chemical activity

Engineering Contradiction:
Improvestorage durationVSAvoidbattery safety
Core Design Contradiction:
Duration of action of stationary objectVSReliability

Solution Approach 1:

The system performs preliminary action by detecting when the battery is not in use for a threshold time and automatically initiating controlled self-discharge before damage can occur. The control unit monitors the battery state and activates the discharging circuit in advance to reduce voltage to a safe level, preventing swelling or leaking that would otherwise happen during long-term storage.

Inventive Principle:
Principle #10Preliminary action

2Use of energy by moving object

If the battery assembly is left charged for extended periods, then power availability is maintained, but chemical activity causes damage reducing battery life

Engineering Contradiction:
Improvepower availabilityVSAvoidbattery life
Core Design Contradiction:
Use of energy by moving objectVSDuration of action of moving object

Solution Approach 1:

The system uses feedback by continuously monitoring the battery voltage and state of charge through the detection unit. When the battery is detected to be in an unused state for a threshold time, the control unit receives feedback and automatically activates the self-discharge circuit to reduce voltage to a safe storage level, thereby extending battery life while maintaining power availability when needed.

Inventive Principle:
Principle #23Feedback

3Reliability

If a battery management system implements controlled self-discharge, then battery damage is prevented during storage, but system complexity increases

Engineering Contradiction:
Improvebattery safetyVSAvoidmanagement system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The battery management system performs self-service by automatically detecting its own storage state and initiating corrective self-discharge actions without external intervention. The control unit monitors the battery's voltage and usage state, and when threshold conditions are met, it automatically activates the discharging circuit through the switch, enabling the system to manage itself and prevent damage without requiring complex external control mechanisms.

Inventive Principle:
Principle #25Self-service

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 approach prevents damage to battery assemblies during long-term storage by maintaining a safe voltage, extending battery life and ensuring user and environmental safety.

Implementation Method 1

initiating a controlled self-discharge of the battery assembly when the amount of time exceeds a threshold length of time

Methodology Applied
Scientific EffectSelf-discharge: Battery (electricity)

Implementation Method 2

using a self-discharging circuit with a resistor and control switch to manage storage voltage

Methodology Applied
Scientific EffectElectrical Resistance: Electrical Resistance

Data Source

PatentEP3734792B1Battery management system
Publication Date: 2025.07.02 SZ DJI TECH CO LTD
  • EP3734792B1 patent drawingFigure 1
  • EP3734792B1 patent drawingFigure 2
  • EP3734792B1 patent drawingFigure 3

AI summary

A method for assembling an apparatus for managing discharge of a battery assembly is provided, said method comprising: providing the battery assembly comprising one or more battery cells; electrically coupling a self-discharging circuit to the battery assembly; and electrically coupling a battery management system to the self-discharging circuit, wherein the battery management system is configured to control operation of the self-discharging circuit in order to permit controlled self-discharge of the battery assembly, and wherein the battery management system is configured to cause the battery assembly to discharge via the self-discharging circuit when a timer exceeds a threshold length of time. A corresponding apparatus is also provided.