Startup Circuit Undervoltage Lockout for Battery Energy Storage

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Solution Overview

Problem

Existing lithium battery energy storage systems face the risk of permanent damage due to overdischarge, as current undervoltage protection mechanisms can lead to repeated startup instructions, causing excessive power consumption and irreversible damage to the electrochemical cell pack.

Innovation Solution

The proposed energy storage system includes an electrochemical cell pack, a startup circuit, and an auxiliary source circuit, where the startup circuit controls the connection status between the electrochemical cell pack and the auxiliary source circuit based on an external input signal. The system employs a first control circuit and a second control circuit, including voltage divider circuits, to automatically perform undervoltage protection by maintaining a disconnected state when the battery voltage is below a specified threshold, preventing overdischarge and subsequent damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If software-based undervoltage protection is used, then the system can detect low battery voltage, but repeated startup instructions may cause overdischarge and permanent damage to the electrochemical cell pack

Engineering Contradiction:
Improvebattery protectionVSAvoidoverdischarge damage
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The startup circuit is designed to detect battery voltage status before allowing startup to occur. The voltage detection mechanism proactively identifies undervoltage conditions and prevents startup execution, thereby avoiding overdischarge damage before it can happen. This preliminary detection and prevention approach eliminates the harmful effect of repeated startup attempts during low voltage states.

Inventive Principle:
Principle #10Preliminary action

2Adaptability or versatility

If the startup circuit allows repeated startup attempts, then the system maintains operational flexibility, but continuous power consumption during undervoltage causes battery overdischarge

Engineering Contradiction:
Improvestartup flexibilityVSAvoidbattery power consumption
Core Design Contradiction:
Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The startup circuit incorporates a feedback mechanism that continuously monitors battery voltage and uses this information to control whether startup operations are permitted. When voltage falls below the threshold, the feedback signal blocks startup execution, preventing further power consumption. This closed-loop control maintains operational flexibility when voltage is adequate while automatically preventing energy loss when voltage is insufficient.

Inventive Principle:
Principle #23Feedback

3Productivity

If the auxiliary source circuit continuously operates, then the system maintains readiness for operation, but power consumption from the electrochemical cell pack causes voltage drop and undervoltage protection activation

Engineering Contradiction:
Improvesystem readinessVSAvoidbattery power consumption
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

The system dynamically adjusts the operational state of the auxiliary source circuit based on real-time battery voltage conditions. When voltage is sufficient, the auxiliary circuit can operate to maintain system readiness. When voltage drops below the threshold, the system automatically transitions to a standby state, blocking auxiliary circuit operation to prevent further power consumption. This dynamic state adjustment balances productivity requirements with energy conservation.

Inventive Principle:
Principle #15Dynamics

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 effectively prevents overdischarge of the electrochemical cell pack and mitigates the risk of permanent damage by automatically performing undervoltage protection, ensuring the energy storage system operates safely and efficiently.

Implementation Method 1

the first voltage divider circuit includes a switching device and a voltage divider that are connected in series... When the switching device is turned on, a voltage difference is generated at two ends, so that when the switching device is turned on, the connection point may generate a turn-on voltage that is lower than a battery voltage

Methodology Applied
Scientific EffectVoltage division: Ohm's Law

Data Source

PatentEP4498567A1Energy storage system
Publication Date: 2025.01.29 HUAWEI DIGITAL POWER TECH CO LTD
  • EP4498567A1 patent drawingFigure 1~2
  • EP4498567A1 patent drawingFigure 3
  • EP4498567A1 patent drawingFigure 4

AI summary

An embodiment of this application discloses an energy storage system. The energy storage system includes an electrochemical cell pack, a startup circuit, and an auxiliary source circuit. The startup circuit includes a first control circuit and a second control circuit, the second control circuit includes a first voltage divider circuit and a second voltage divider circuit that are connected in series, the first voltage divider circuit includes a switching device and a voltage divider that are connected in series, and a connection point between the first voltage divider circuit and the second voltage divider circuit is connected to a first control end of the first control circuit. When the switching device is turned on, a voltage of the electrochemical cell pack needs to meet a specified condition, so that a turn-on voltage generated by the connection point between the first voltage divider circuit and the second voltage divider circuit is greater than a specified threshold voltage, and the first control circuit turns on a line between the electrochemical cell pack and the auxiliary source circuit, to enable the battery pack to supply power to the auxiliary source circuit. This ensures that power cannot be supplied to the auxiliary source circuit in a manner that the switching device is turned on when the voltage of the electrochemical cell pack is excessively low, and effectively prevents overdischarge of the electrochemical cell pack.