Electric Storage System Voltage Stress Reduction

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Solution Overview

Problem

Existing electric storage systems with current breakers face challenges in managing high voltages, leading to increased size and cost, as well as issues with inrush currents and heat generation, particularly when current breakers are activated during charge or discharge cycles.

Innovation Solution

The electric storage system incorporates relays, smoothing capacitors, and a current limiting resistance, with an intermediate line connecting electric storage elements, allowing for reduced voltage application to current breakers, preventing inrush currents, and monitoring heat generation through current sensors, thereby controlling charge and discharge to manage power and temperature effectively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the current breaker is provided with a structure which withstands high voltage, then the safety and reliability are improved, but the size and cost of the current breaker increase

Engineering Contradiction:
ImprovesafetyVSAvoidsize
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The patent divides the electric storage system into multiple independent electric storage elements, each with its own current breaker. By segmenting the high voltage system into lower voltage subsystems, each current breaker only needs to withstand a portion of the total voltage, reducing the size and cost while maintaining overall system safety through modular isolation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediate voltage level by connecting electric storage elements in series with individual current breakers, creating a stepped voltage architecture. This intermediary structure allows current breakers to operate at lower voltage levels while the overall system achieves high voltage, resolving the contradiction between safety requirements and component size.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the current breaker is provided with a structure which withstands high voltage, then the safety and reliability are improved, but the cost increases

Engineering Contradiction:
ImprovesafetyVSAvoidcost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent divides the electric storage system into multiple independent electric storage elements, each with its own current breaker. By segmenting the high voltage system into lower voltage subsystems, each current breaker only needs to withstand a portion of the total voltage, reducing the size and cost while maintaining overall system safety through modular isolation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent employs multiple simpler, lower-cost current breakers distributed across individual electric storage elements rather than one complex high-voltage current breaker. This approach uses multiple inexpensive components to achieve the safety function that would otherwise require an expensive high-voltage rated component.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Stability of the object's composition

If smoothing capacitors are connected directly to the electric storage apparatus, then the power supply stability is improved, but inrush current and heat generation occur

Engineering Contradiction:
Improvepower supply stabilityVSAvoidinrush current
Core Design Contradiction:
Stability of the object's compositionVSObject-generated harmful factors

Solution Approach 1:

The patent introduces relays that control the sequential connection of smoothing capacitors to the electric storage apparatus. Before full power connection, the relays pre-charge the capacitors through controlled pathways, preventing sudden inrush current while maintaining the power supply stability benefit of having smoothing capacitors in the system.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent uses controllable relays to dynamically manage the connection state of smoothing capacitors, transitioning from disconnected to connected states based on system conditions. This dynamic control allows the system to benefit from power supply stability when needed while avoiding inrush current by controlling the timing and manner of capacitor engagement.

Inventive Principle:
Principle #15Dynamics

4Power

If multiple electric storage elements are connected in series to increase voltage, then the power output is improved, but the voltage applied to current breaker terminals increases

Engineering Contradiction:
Improvepower outputVSAvoidvoltage stress
Core Design Contradiction:
PowerVSStress or pressure

Solution Approach 1:

The patent divides the high voltage electric storage system into multiple series-connected elements, each with its own current breaker. This segmentation ensures that each current breaker only experiences a fraction of the total system voltage, reducing voltage stress on individual components while maintaining high power output through the series configuration.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from a single high-voltage current breaker architecture to a distributed multi-element architecture, adding the dimension of spatial distribution and modular organization. This dimensional change allows the system to achieve high voltage and power output while individual components operate at lower, more manageable voltage levels.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 configuration reduces the size and cost of current breakers, prevents inrush currents, and effectively manages heat generation, enhancing the overall efficiency and reliability of the electric storage system by limiting power and controlling temperature.

Implementation Method 1

Overcharging or overdischarging of the cell may produce gas to increase the internal pressure of the cell. When the internal pressure of the cell is increased, the current breaker is deformed to break a current path within the cell.

Methodology Applied
Scientific EffectPressure increase: Pressure Increase

Implementation Method 2

the plurality of smoothing capacitors are connected in series between the positive electrode line and the negative electrode line

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 3

The current limiting resistance is also placed on the intermediate line

Methodology Applied
Scientific EffectElectrical resistance: Electrical Resistance

Implementation Method 4

Each of the relays is placed on the positive electrode line, the negative electrode line, and an intermediate line

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP2773011B1Electricity-storage system
Publication Date: 2016.12.28 TOYOTA JIDOSHA KK
  • EP2773011B1 patent drawingFigure 1
  • EP2773011B1 patent drawingFigure 2~3
  • EP2773011B1 patent drawingFigure 4

AI summary

[PROBLEM] To reduce a voltage applied between terminals of a current breaker in an electric storage element when the current breaker is activated. [SOLVING MEANS] An electric storage system includes an electric storage apparatus, relays, a plurality of smoothing capacitors, and a current limiting resistance. The electric storage apparatus has a plurality of electric storage elements connected in series. Each of the electric storage elements includes a current breaker breaking an electric current path inside the electric storage element. The plurality of smoothing capacitors are connected in series between a positive electrode line and a negative electrode line which connect the electric storage apparatus to a load. Each of the relays is placed on the positive electrode line, the negative electrode line, and an intermediate line. The intermediate line connects a connecting point of two of the electric storage elements included in the electric storage apparatus and a connecting point of the plurality of smoothing capacitors. The current limiting resistance is also placed on the intermediate line.