Redundant Bus Bar Shunt Layout for Temperature-Compensated Current Sensing
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Solution Overview
Problem
Existing current measurement systems in batteries, particularly in electric vehicle batteries, face challenges with measurement errors due to temperature fluctuations and differences in current values, leading to inaccurate determination of the battery's state, especially when using shunt resistors in redundancy configurations.
Innovation Solution
A bus bar assembly with multiple shunt resistors and independent analog-to-digital converters (ADCs) for redundancy, 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 shunt resistors are used for current measurement, then measurement precision is improved, but temperature fluctuations cause measurement errors
Solution Approach 1:
The patent applies temperature compensation by changing the measurement parameters to account for temperature effects. Multiple shunt resistors with different temperature coefficients are used, and their measurements are combined through calculation to compensate for temperature-induced errors, thereby maintaining measurement precision across varying temperatures.
Solution Approach 2:
The patent divides the current measurement function into multiple parallel shunt resistors instead of using a single resistor. Each shunt resistor provides a measurement channel, and their results are combined through redundancy verification and compensation calculations to eliminate temperature-related errors.
2Reliability
If redundancy design with two or more resistors is used, then reliability is improved, but measurement errors increase when current values differ significantly
Solution Approach 1:
The patent implements a verification mechanism where the control unit continuously monitors the difference between current values measured by multiple shunt resistors. When the difference exceeds a predetermined threshold, the system identifies and excludes the erroneous measurement, providing feedback to maintain accurate current measurement while preserving redundancy benefits.
Solution Approach 2:
The patent dynamically adjusts the measurement strategy by verifying current values from multiple shunt resistors in real-time. The system adapts by selecting the valid measurement based on predefined criteria, making the measurement process flexible and responsive to changing conditions rather than relying on a fixed single-channel approach.
3Reliability
If multiple shunt resistors are used for redundancy, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent merges multiple shunt resistors into a single integrated bus bar assembly structure. The multiple resistors are positioned adjacently and electrically connected in parallel between the same terminal holes, combining their functions while sharing a common structural framework, thereby reducing overall complexity compared to separate measurement systems.
Solution Approach 2:
The bus bar assembly serves multiple functions simultaneously: it provides structural support for battery connections, integrates multiple current measurement channels through embedded shunt resistors, and enables redundancy verification. This multi-functionality reduces the need for separate components and simplifies the overall system architecture.
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 highly reliable current measurement by reducing measurement errors and enhancing the robustness of bus bars, allowing for precise determination of battery state and reducing gaps in current values.
Implementation Method 1
When a shunt resistor is integrated into the middle of a wire, 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
an ammeter connected in series to a terminal formed by cutting the wire can measure the current flowing through the wire using the intensity of the magnetic field formed in the coil
Data Source
AI summary
A bus bar assembly and current measuring device configured to reduce measurement errors through linearity compensation and temperature compensation for the difference in values of two or more measured currents, thereby achieving high-accuracy current measurement, is presented. The present invention discloses a bus bar assembly including: a first conductive plate and a second conductive plate each 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. According to the present invention, stable and highly reliable current measurement is possible through multiple shunt resistors based on a redundancy design.