Energy Storage Bypass Circuit for Safe Fault Discharging

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing energy storage systems face risks of accidental short-circuiting and unsafe discharging during maintenance or faults, posing hazards to humans and equipment due to high forces and heat generation, necessitating improved protection circuits for safe bypassing of energy storage units.

Innovation Solution

The energy storage system incorporates a protection circuit with a series-connected first switch and parallel-connected second switch, along with a resistor, allowing controlled bypassing of energy storage units by gradually adjusting resistance values through sequential switch closures, thereby preventing accidental short-circuiting and ensuring safe discharging.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a single switch is used to bypass energy storage units, then the bypass operation is simple, but accidental direct short-circuiting cannot be prevented

Engineering Contradiction:
Improvebypass operation simplicityVSAvoidshort-circuit prevention
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The bypass switch is segmented into two separate switches (first switch and second switch) that must both be closed to complete the bypass path. This segmentation prevents accidental short-circuiting because a single switch closure cannot create a direct bypass path, thereby improving reliability while maintaining operational simplicity through standardized switching mechanisms.

Inventive Principle:
Principle #1Segmentation

2Object-affected harmful factors

If energy storage units are bypassed during faults or maintenance, then safety is improved, but system shutdown is required which reduces productivity

Engineering Contradiction:
Improvesafety during dischargingVSAvoidsystem availability
Core Design Contradiction:
Object-affected harmful factorsVSProductivity

Solution Approach 1:

The energy storage system is segmented into multiple independently bypassable units. When a fault occurs in one unit, only that specific unit needs to be bypassed through its dedicated protection circuit, while other units continue to operate. This segmentation enables localized safety measures without requiring complete system shutdown, thereby maintaining productivity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A protection circuit acts as an intermediary between the faulty energy storage unit and the rest of the system. This protection circuit includes switches and resistors that safely isolate the problematic unit while allowing current to bypass it through controlled paths, enabling continuous operation of healthy units and maintaining system availability.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If direct bypassing of energy storage units is enabled, then operation continuity is improved, but the risk of accidental short-circuiting increases

Engineering Contradiction:
Improveoperation continuityVSAvoidshort-circuit risk
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The bypass path is segmented into multiple series-connected switches (first switch and second switch) rather than using a single direct bypass switch. This segmentation ensures that operation continuity is maintained through controlled bypassing while the multi-switch configuration prevents accidental short-circuiting by requiring multiple independent actions to complete the bypass path.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Resistors are introduced as intermediary elements in the bypass path, connected in series with the switches. These resistors limit current flow during bypass operations, preventing direct short-circuiting while still enabling operational continuity. The resistors act as safety intermediaries that control the bypass current rather than allowing unrestricted direct bypassing.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 ensures continuous operation of the energy storage system while safely discharging faulty units, reducing the risk of exceeding switch and unit ratings, and maintaining system availability without shutdowns.

Implementation Method 1

By providing the first resistor in series with the first switch and in parallel to the second switch, the first resistor can be switched into a current path or removed from a current path through the protection circuit depending on the status of the switches

Methodology Applied
Scientific EffectElectrical Resistance: Electrical Resistance

Implementation Method 2

The energy storage units may comprise one or more energy storage cells like supercapacitors or batteries

Methodology Applied
Scientific EffectElectrochemical energy storage: Battery (electricity)

Implementation Method 3

The energy storage units may comprise one or more energy storage cells like capacitors, e.g. supercapacitors

Methodology Applied
Scientific EffectElectrostatic energy storage: Capacitance

Data Source

PatentEP4607744A1Energy storage system and method for operating a protection circuit in an energy storage system
Publication Date: 2025.08.27 HITACHI ENERGY LTD
  • EP4607744A1 patent drawingFigure 1~2
  • EP4607744A1 patent drawingFigure 3A~3C
  • EP4607744A1 patent drawingFigure 4~5F

AI summary

An energy storage system (1) comprising a plurality of energy storage units (2, 2n) and comprising one or more protection circuits (3, 3n, 4) enabling bypassing one or more of the energy storage units (2, 2n), wherein at least one of the protection circuits (3, 3n, 4) comprises a first switch (S1, Sn1, Sa) and a first resistor (R1, Rn1, Ra) electrically connected in series and comprises a second switch (S2, Sn2, Sb) electrically connected in series with the first switch (S1, Sn1, Sa) and electrically connected in parallel with the first resistor (R1, Rn1, Ra).