Battery Cell Voltage Compensation Across Interconnection Bars
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Solution Overview
Problem
Existing battery management systems in electric and hybrid vehicles underutilize slave elements due to imbalanced measurement channels, leading to increased costs and mass, and result in erroneous voltage estimations due to interconnection bar biases, affecting the accuracy of SOH and SOC calculations.
Innovation Solution
A method and system that compensates for interconnection bar voltages by estimating a compensation value based on temperature and current measurements, allowing for refined voltage estimation and improved battery management through corrected voltage values, thereby optimizing operating conditions and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the same slave element is used to collect data at two separate modules to reduce the number of slave elements, then the cost and mass of the battery device are reduced, but the voltage measurements are biased by the interconnection bar voltage leading to erroneous parameter estimation
Solution Approach 1:
The patent segments the voltage measurement function by separating the interconnection bar voltage from the cell voltage. The slave element measures the combined voltage, but the system processes this measurement by subtracting the estimated interconnection bar voltage component, effectively segmenting the total voltage into measurable cell voltage and parasitic interconnection bar voltage parts.
Solution Approach 2:
The patent introduces an intermediary estimation process for the interconnection bar voltage. By estimating the interconnection bar voltage based on temperature and current measurements, the system acts as a mediator to remove the parasitic voltage component from the slave element measurement, thereby recovering the accurate cell voltage without requiring additional hardware.
2Measurement precision
If more slave elements are used to equip all modules to ensure full measurement capacity, then the voltage measurement accuracy is improved, but the cost and mass of the battery device increase
Solution Approach 1:
The patent makes the slave element universal by enabling a single slave element to serve multiple modules simultaneously. Through the voltage compensation method, one slave element can accurately measure cell voltages across two different modules by compensating for the interconnection bar voltage, thereby eliminating the need for dedicated slave elements for each module.
Solution Approach 2:
The patent changes the measurement parameters by measuring not only voltage but also temperature and current. These additional parameter measurements enable the estimation and compensation of interconnection bar voltage, allowing accurate cell voltage measurement with fewer slave elements. The system transforms the measurement approach from direct voltage-only measurement to multi-parameter measurement with computational compensation.
3Device complexity
If voltage measurements including interconnection bar voltage are used for parameter estimation, then the measurement process is simple, but the estimated parameters such as SOH and SOC become erroneous
Solution Approach 1:
The patent implements a feedback mechanism where temperature and current measurements are continuously monitored and used to estimate the interconnection bar voltage. This estimated compensation value is fed back into the voltage measurement process to correct the cell voltage estimation, thereby improving parameter estimation accuracy while maintaining measurement system simplicity.
Solution Approach 2:
The patent replaces the physical hardware solution (additional slave elements or interconnection bar modifications) with a computational/electronic solution. Instead of changing the physical measurement architecture, the system uses software-based estimation and compensation algorithms to eliminate the interconnection bar voltage error, substituting mechanical/hardware complexity with computational processing.
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
The method and system provide accurate voltage compensation, enhancing the estimation of battery parameters like SOH and SOC, reducing unnecessary safety triggers, and optimizing charging and discharging processes, thus improving battery performance and longevity.
Implementation Method 1
a step of measuring a voltage specific to each cell, whether or not linked to an interconnection bar, by means of slave elements
Implementation Method 2
a step of measuring the temperature of each module, each temperature measurement being associated with the interconnection bar(s) linked to the module in question
Implementation Method 3
a step of measuring a current flowing in the battery device
Implementation Method 4
a step of estimating a voltage compensation value specific to each cell linked to an interconnection bar, the compensation value corresponding to an estimated voltage of the interconnection bar in question
Data Source
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AI summary
The invention relates to a management system and method enabling a more suitable estimation of the voltage of the cells connected to an interconnection bar so as to optimize the durability and operation of the performance of the processing device.