Pattern Resistor Current Detection with Temperature Compensation
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Solution Overview
Problem
Existing battery packs lack accurate current detection, which is crucial for monitoring charging and discharging processes, battery health, and lifespan, due to limitations in detecting high currents and temperature-compensated resistance values.
Innovation Solution
A circuit module with a pattern resistor and a current detecting unit on a multi-layer printed circuit board (PCB), utilizing a temperature sensor to compensate for resistance changes, allowing precise current measurement by calculating voltage and resistance values, and a protective circuit module within the battery pack for controlling charging and discharging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional current detection method is used in battery packs, then the device complexity is reduced, but the measurement precision of current detection deteriorates
Solution Approach 1:
The patent merges the current detection function with the existing PCB structure by using a pattern resistor that is integrated into the circuit board layout. The pattern resistor is formed as part of the PCB trace pattern, combining the functions of current conduction and current sensing into a single structure, thereby improving measurement precision without significantly increasing device complexity
Solution Approach 2:
The patent introduces a temperature sensor as an intermediary element to compensate for temperature-induced resistance changes in the pattern resistor. By measuring the temperature and using it to correct the resistance value calculations, the system achieves more accurate current detection while maintaining a relatively simple overall structure
2Measurement precision
If temperature compensation is implemented for resistance value, then the measurement precision improves, but the device complexity increases
Solution Approach 1:
The pattern resistor is designed to be adjacent to a large-area ground structure that acts as a heat sink, allowing the resistor to self-regulate its temperature by dissipating heat to the ground. This self-cooling mechanism reduces temperature drift without requiring active temperature control systems, thereby improving resistance value accuracy while minimizing additional complexity
Solution Approach 2:
A temperature sensor is positioned near the pattern resistor to serve as an intermediary that monitors temperature changes. The sensor's output is used to dynamically adjust or compensate for resistance value calculations in the control unit, achieving accurate temperature-compensated current measurement with minimal additional hardware
3Manufacturing precision
If a serpentine pattern resistor is used, then the manufacturing precision is improved, but the area of the resistor increases
Solution Approach 1:
The patent utilizes the multi-layer structure of the PCB to reduce the planar area occupied by the pattern resistor. By routing the serpentine pattern across multiple copper layers and using vias to connect them, the resistor achieves its required resistance value and precision while occupying less surface area on any single layer, effectively transitioning the problem from 2D to 3D space
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
Enables accurate detection of current flowing in the battery pack, improving charging and discharging control, extending battery life, and reducing manufacturing costs by using copper pattern resistors with a serpentine shape for efficient space utilization.
Implementation Method 1
a current detecting unit electrically connected to both ends of the pattern resistor, and for detecting a current flowing in the pattern resistor based on a voltage across the ends of the pattern resistor
Implementation Method 2
a temperature sensor electrically connected to the current detecting unit and being adjacent to the pattern resistor so as to sense the temperature of the pattern resistor
Implementation Method 3
to compensate for a resistance value of the pattern resistor in accordance with the temperature input from the temperature sensor
Data Source
AI summary
A circuit module of a battery pack includes a pattern resistor having conductivity; a temperature sensor that is adjacent to the pattern resistor and that senses a temperature of the pattern resistor; and a current detecting unit that is electrically connected to both ends of the pattern resistor, that is electrically connected to the temperature sensor, and that detects a current flowing in the pattern resistor based on a voltage across the ends of the pattern resistor and a temperature of the pattern resistor.