Electric Storage System Current Breaker Operation Detection
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Solution Overview
Problem
In electric storage systems with parallel-connected cells, operating a current breaker affects the current load on other cells, necessitating a method to detect its operation effectively to control charge and discharge, different from existing techniques.
Innovation Solution
An electric storage system with serially connected blocks, each containing parallel electric storage elements and current breakers, uses a voltage sensor and controller to determine the operation of current breakers by comparing voltage characteristics, calculating sum values and estimating voltages to identify shifts indicative of breaker operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a current breaker is provided for each electric storage element to protect against excessive current, then the reliability of individual cells is improved, but the current load on other cells increases when a breaker operates, creating a harmful effect
Solution Approach 1:
The controller continuously monitors voltage characteristics of electric storage blocks and uses this feedback to detect current breaker operation. When a breaker operates, the voltage characteristic changes are detected and used to control charge/discharge, preventing harmful current load increases on remaining cells
Solution Approach 2:
The controller acts as an intermediary between the current breakers and the charge/discharge system. It detects breaker operation through voltage monitoring and mediates the charge/discharge control to prevent excessive current on remaining cells, thus managing the harmful effect
2Measurement precision
If voltage characteristics are monitored to detect current breaker operation, then the detection accuracy is improved, but the device complexity increases due to additional sensors and control logic
Solution Approach 1:
The voltage sensor serves multiple functions: it monitors the voltage characteristics for breaker operation detection, tracks the state of charge of electric storage blocks, and provides data for charge/discharge control. This multi-functionality improves detection precision without proportionally increasing device complexity
Solution Approach 2:
The system uses its own voltage measurement infrastructure to detect breaker operation, rather than requiring separate dedicated detection sensors. The existing voltage monitoring capability is leveraged for dual purposes, reducing the need for additional hardware
Data Source
AI summary
The state of a plurality of electric storage blocks connected in serial is determined. Each of the electric storage blocks includes a plurality of electric storage elements connected in parallel. Each of the electric storage elements includes a current breaker configured to break a current path in the electric storage element. When a first voltage characteristic is shifted from a second voltage characteristic, it is determined that the current breaker is operated. The first voltage characteristic is acquired from a voltage sensor acquiring an open circuit voltage of each electric storage block and indicates a change in the open circuit voltage with respect to a capacity of the electric storage block. The second voltage characteristic is calculated from a capacity retention rate and a variation of the capacity and indicates a change in the open circuit voltage with respect to the capacity of the electric storage block.