Redundant Bus Bar Shunt Layout for Accurate Current Sensing
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Solution Overview
Problem
Existing current measurement systems using shunt resistors in batteries face challenges with measurement errors due to temperature variations and rapid current changes, particularly in high-voltage applications, leading to inaccurate determination of battery state and increased temperature rise.
Innovation Solution
A dual configuration current measuring device with two shunt resistors and independent analog-to-digital converters, combined with temperature prediction algorithms and synchronization, to ensure accurate current measurement through linearity and temperature compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single shunt resistor is used for current measurement, then the device complexity is low, but the measurement precision and reliability deteriorate due to temperature variations and rapid current changes
Solution Approach 1:
The measurement system is segmented into multiple independent measurement channels, each with its own shunt resistor and ADC. This segmentation allows parallel measurement of current through different resistors, enabling redundancy and improved precision through comparison of multiple measurements rather than relying on a single measurement point
Solution Approach 2:
Temperature compensation is performed as a preliminary action before final current calculation. The system measures temperature variations and applies compensation algorithms to the raw current measurements from multiple shunt resistors, thereby pre-correcting for temperature-induced measurement errors before the final current value is determined
2Reliability
If multiple shunt resistors are used for redundancy measurement, then the reliability improves, but measurement errors increase due to temperature rise from high current conduction
Solution Approach 1:
The system implements feedback through continuous temperature monitoring and compensation. Temperature sensors monitor the thermal state of the bus bar assembly, and this temperature information is fed back to the control unit which applies real-time compensation to the current measurements from multiple shunt resistors, thereby maintaining measurement accuracy despite temperature variations caused by high current conduction
Solution Approach 2:
The system changes the measurement parameters by using multiple shunt resistors with different resistance values (e.g., 50mΩ and 100mΩ) to measure the same current. This allows the system to select or combine measurements based on operating conditions, and applies temperature compensation by adjusting measurement parameters according to the thermal state of the system
3Measurement precision
If high current values are measured for accurate battery state determination, then the measurement precision improves, but the temperature rise increases causing larger error ranges
Solution Approach 1:
Temperature sensors act as intermediaries between the high-current measurement system and the control unit. These sensors monitor the thermal effects of high current conduction and transmit temperature information to the control unit, which then applies compensation algorithms to maintain measurement precision without being directly affected by the high temperature conditions
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 solution provides stable and reliable current measurement by reducing errors and enhancing the robustness of bus bars, enabling precise determination of battery state and reducing temperature-related inaccuracies.
Implementation Method 1
the voltage formed at both ends of the shunt resistor is measured, and a current value can be calculated from the measured voltage using Ohm's law
Implementation Method 2
as the conduction-time of the current and the current value increases, the battery's temperature rises
Data Source
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AI summary
The present invention discloses a bus bar assembly including: a first conductive plate composed of a plurality of parts; a second conductive plate composed of a plurality of parts; and an insulator formed between the first conductive plate and the second conductive plate, wherein a common first terminal hole is formed at one end of the first conductive plate, one end of the second conductive plate, and one end of the insulator, a common second terminal hole is formed at respective opposite ends of the first conductive plate, the second conductive plate, and the insulator, the first conductive plate includes at least one first shunt resistor, the first shunt resistor, between the parts of the first conductive plate, electrically connects a part where the first terminal hole is formed and a part where the second terminal hole is formed, the second conductive plate includes at least one second shunt resistor, the second shunt resistor, between the parts of the second conductive plate, electrically connects a part where the first terminal hole is formed and a part where the second terminal hole is formed, and sensing pins necessary for measuring a voltage drop are formed at both ends of the first shunt resistor and the second shunt resistor. According to the present invention, stable and highly reliable current measurement is possible through multiple shunt resistors based on a redundancy design.