Battery Cell Terminal Voltage Estimation with Busbar Drop Compensation
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Solution Overview
Problem
Existing battery management systems face inaccuracies in estimating battery cell terminal voltages due to the influence of electrical connection elements like busbars, which are not accounted for in current measurement methods, leading to reduced quality of battery management and state-of-charge estimation.
Innovation Solution
A computer system that utilizes a model of voltage drop across electrical connection elements to correct measured voltage values, considering factors such as current and temperature, to accurately estimate battery cell terminal voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If voltage measurements are performed including electrical connection elements to reduce sensor quantity, then device complexity is reduced, but measurement precision deteriorates due to unaccounted voltage drops
Solution Approach 1:
The patent introduces an electrical connection element model as an intermediary component that mediates between the measurement system and the battery cell. This model characterizes the voltage drop properties of connection elements (busbars, tabs, etc.) and enables the system to compensate for their influence without adding physical sensors. The model acts as a virtual intermediary that corrects measurements taken at accessible points to infer true terminal voltages.
Solution Approach 2:
The patent replaces physical measurement infrastructure (additional voltage sensors placed directly at battery cell terminals) with a computational model-based approach. Instead of mechanically adding more sensing hardware, the solution substitutes a mathematical model that processes existing measurements and compensates for connection element effects, thereby reducing hardware complexity while maintaining or improving measurement accuracy.
2Productivity
If single spot measurements are performed to reduce measurement data size, then processing resources are conserved, but measurement precision deteriorates due to inclusion of connection element voltage drops
Solution Approach 1:
The patent extracts and separates the voltage drop contribution of electrical connection elements from the total measured voltage. By using the connection element model to quantify and remove this unwanted component, the system obtains the true battery cell terminal voltage from measurements that include both cell and connection element contributions. This extraction process maintains processing efficiency while improving accuracy.
Solution Approach 2:
The patent implements a feedback mechanism where the electrical connection element model provides correction values based on measured currents and temperatures. The model continuously adapts to changing operating conditions (current magnitude, temperature) and feeds back compensation amounts that refine the terminal voltage estimation, thereby maintaining high accuracy with minimal additional 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
Improves the accuracy of battery cell terminal voltage estimation by compensating for voltage drops across connection elements, enhancing the precision of state-of-charge calculations and overall battery management.
Implementation Method 1
a terminal of the battery cell is electrically connected to another object (such as e.g. another battery cell, a battery terminal, or similar) of the battery via an electrical connection element (such as e.g. a cell-to-cell busbar)
Implementation Method 2
obtain a first voltage drop value indicative of a voltage drop across at least i) the battery cell and ii) at least a part of the electrical connection element
Data Source
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AI summary
A computer system (400) for estimating a terminal voltage (VCi) of a battery cell of a battery (100) is provided. The terminal is electrically connected to another object (such as another battery cell) via e.g. a cell-to-cell busbar. Processing circuitry (410) is configured to obtain a voltage drop (V(i-1) - Vi) across at least the battery cell and at least part of the busbar; obtain a voltage correction value (VZ(i-1),2;VZi,1) from a model (430) of voltage drop across the busbar, and estimate the terminal voltage based on the voltage drop corrected by the voltage correction value (Vci ≈ V(i-1) - Vi - VZ(i-1),2 - VZi,1). A corresponding battery arrangement, vehicle, method and computer program product are also provided.