Switched Accumulator Battery Charge Tracking with One Current Sensor
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Solution Overview
Problem
Switched electric accumulator batteries face challenges in accurately estimating the state of charge of each accumulator due to the voltage evolution curve's slight slope in lithium iron phosphate accumulators, requiring additional current measurements, which increases manufacturing costs when using multiple current sensors.
Innovation Solution
A method utilizing a single current sensor and a control circuit system to manage the connection and disconnection of accumulators, updating counters to track charge circulation, and determining the state of charge through global and local counters, reducing the need for multiple sensors and improving precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple current sensors are used to measure current in each accumulator, then measurement precision of state of charge is improved, but manufacturing cost increases
Solution Approach 1:
The patent combines multiple current measurement functions into a single current sensor by using switching elements to connect different accumulators to the same sensor at different times. The control unit coordinates the switching to ensure that the single sensor sequentially measures current through all accumulators, replacing the need for multiple simultaneous sensors and reducing cost while maintaining measurement precision.
Solution Approach 2:
The patent introduces dynamic switching between static connections. The switching elements dynamically reconfigure the circuit connections based on control signals, allowing a single sensor to access multiple accumulators at different time moments. This dynamic reconfiguration enables cost reduction while preserving the capability to measure each accumulator's current accurately.
2Ease of manufacture
If a single current sensor is used to reduce manufacturing cost, then manufacturing cost decreases, but measurement precision of state of charge deteriorates
Solution Approach 1:
The control unit performs preliminary coordination by pre-planning the switching sequence before measurements are taken. It activates switching elements in a predetermined order to connect the single sensor to each accumulator sequentially, ensuring that all necessary current measurements are captured at the appropriate moments. This preliminary control action guarantees that cost reduction does not compromise measurement precision.
Solution Approach 2:
The system implements feedback control where the control unit monitors the switching states and sensor measurements, then adjusts the switching sequence to ensure complete and accurate current measurement for each accumulator. The feedback mechanism verifies that the single sensor has captured all necessary data points, maintaining precision despite using fewer sensors.
3Device complexity
If accumulators are statically connected to simplify the system, then device complexity decreases, but the ability to perform precise state of charge estimation for switched batteries deteriorates
Solution Approach 1:
The patent segments the battery system into modular units, each with its own switching elements and control logic. This segmentation allows the system to maintain simple static connections within modules while enabling dynamic reconfiguration between modules through the switching elements. The segmented architecture reduces overall complexity while preserving the ability to perform precise measurements.
Solution Approach 2:
The switching elements serve multiple functions: they act as connection switches for the single current sensor, serve as isolation elements for voltage measurements, and enable dynamic reconfiguration of the battery architecture. This multi-functionality reduces the need for separate dedicated components, simplifying the overall system while maintaining measurement precision.
Data Source
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AI summary
The invention relates to a method for controlling a battery (5) comprising a first control circuit (BMS) and a plurality of modules (Ei) which are arranged between first and second terminals (phase, neutral). Each module comprises electrical accumulators. The battery further comprises a sensor (CS) for the current which passes through the first terminal. The method comprises the following successive steps: updating a first counter which represents the quantity of charge flowing through the first terminal; for each electrical accumulator, upon each connection of the electrical accumulator to the other electrical accumulators, storing, in a first data item, the value of the first counter upon the connection of the electrical accumulator, and upon each disconnection of the electrical accumulator from the other electrical accumulators, storing a second counter which is equal to the difference between the value of the first counter upon disconnection of the electrical accumulator and the first data item of the electrical accumulator.