Battery Cell Terminal Current Sensing Without Sense Resistors
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Solution Overview
Problem
Existing battery management systems face challenges in accurately measuring current sourced from or sunk by lithium-ion battery cells, particularly in multi-cell configurations where uneven state of charge can lead to reduced capacity and cell life, and require careful management to operate within safe operating areas.
Innovation Solution
The electric battery incorporates plural measurement arrangements electrically coupled to spaced apart locations on the positive and negative terminals of each cell, measuring potential difference to determine current without additional sense resistors, using parasitic resistance and temperature adjustments to calculate current based on Ohm's Law, and includes processors and communication circuits for data processing and transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If discrete sense resistors or Hall Effect devices are used to measure current, then current measurement capability is achieved, but device complexity and manufacturing cost increase
Solution Approach 1:
The battery cell terminals themselves serve as the measurement element through their inherent parasitic resistance. The measurement arrangement utilizes the natural resistance of the terminal structure without requiring external sense resistors, making the system self-sufficient and eliminating additional components.
Solution Approach 2:
The terminal structure performs dual functions: it serves as both the electrical connection point and the current measurement element. By measuring voltage across the parasitic resistance inherent in the terminal, the same structural component enables both power transmission and current sensing.
2Measurement precision
If additional sense resistors are added to measure current, then current measurement is enabled, but manufacturing cost and device complexity increase
Solution Approach 1:
The terminal structure itself provides the measurement function through its inherent parasitic resistance, eliminating the need for separately manufactured sense resistors and reducing overall manufacturing complexity and cost.
3Measurement precision
If measurement arrangements are added to each battery cell, then current measurement capability is improved, but device complexity increases
Solution Approach 1:
The terminal structure performs dual functions as both electrical connection and measurement element, reducing overall device complexity by eliminating separate sense resistors while maintaining current measurement capability across multiple battery cells.
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 solution allows for precise measurement of current flowing through each battery cell, reducing the need for additional sense resistors, enhancing safety and efficiency by operating within safe operating areas and maintaining cell health, while also enabling effective data communication for supervisory control.
Implementation Method 1
measuring potential difference to determine current without additional sense resistors, using parasitic resistance and temperature adjustments to calculate current based on Ohm's Law
Implementation Method 2
using parasitic resistance and temperature adjustments to calculate current based on Ohm's Law
Implementation Method 3
each battery cell comprising a container, which contains an electrochemical arrangement
Data Source
AI summary
The present invention relates to an electric battery (10). The electric battery (10) comprises plural battery cells (12), with each battery cell comprising a container. The container contains an electrochemical arrangement. Each battery cell (12) comprises positive and negative terminals of sheet form which extend from the electrochemical arrangement. The electric battery further comprises plural measurement arrangements (14), with each of the plural measurement arrangements being electrically coupled to each of two spaced apart locations on one of the positive and negative terminals of a respective one of the plural battery cells. Each of the plural measurement arrangements (14) is configured to measure potential difference between the two spaced apart locations.