Battery Module Thermistor Circuit for Cell-Level Temperature Sensing
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Solution Overview
Problem
Conventional battery modules struggle with non-uniform characteristics among electrochemical cells in a stack, leading to variations in state of charge (SOC) and temperature, which can cause capacity restrictions and premature cell failure, and lack effective cell-level temperature sensing capabilities.
Innovation Solution
Incorporating thermistors into the battery module that serve dual purposes for voltage and temperature sensing, eliminating the need for separate connections between temperature sensors and the BMS, allowing for individual cell temperature measurement without dedicated electrical connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If separate temperature sensors and voltage sensors are used for each electrochemical cell, then measurement precision is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent makes the voltage sensing leads perform dual functions: voltage measurement and temperature sensing. By placing thermistors in thermal contact with the electrochemical cell and using the same electrical leads to sense both voltage and temperature, the system eliminates dedicated temperature sensor connections while maintaining cell-level measurement capability
Solution Approach 2:
The patent combines the voltage sensing circuitry and temperature sensing circuitry into a single integrated system. The thermistors are electrically coupled to the same nodes used for voltage sensing, and the controller simultaneously processes both voltage and temperature data through these shared connections
2Power
If multiple electrochemical cells are connected in series to achieve high voltage, then power output is improved, but non-uniform characteristics cause SOC imbalance and capacity restrictions
Solution Approach 1:
The patent implements individual voltage and temperature monitoring for each electrochemical cell through the shared sensing leads. The controller receives cell-level data from all cells in series and uses this feedback to detect SOC imbalances and temperature variations, enabling targeted management actions to maintain uniformity across the stack
Solution Approach 2:
The patent divides the battery system into individually monitored electrochemical cells, with each cell having its own voltage and temperature measurement capability through the shared leads. This segmentation allows the controller to identify and address non-uniform characteristics in specific cells rather than treating the battery as a single unit
3Ease of manufacture
If conventional battery modules are used without integrated temperature sensing, then manufacturing cost is reduced, but temperature monitoring capability is insufficient
Solution Approach 1:
The patent makes the existing voltage sensing leads perform dual functions by adding thermistors that can be sensed through the same electrical connections. This approach adds temperature sensing capability without requiring separate sensor installations or additional external wiring
Solution Approach 2:
The voltage sensing leads serve themselves by also functioning as temperature sensing conduits. The thermistors are electrically coupled to the cell through the same nodes used for voltage measurement, allowing the existing infrastructure to provide both measurement functions
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 practical and cost-effective cell-level temperature sensing, balancing SOC, and preventing premature cell failure by accurately monitoring and controlling cell temperatures and voltages.
Implementation Method 1
one or more thermistors electrically coupled to the electrochemical cell assembly
Implementation Method 2
loading circuitry configured to draw an electric current through the one or more thermistors when the loading circuitry is activated
Data Source
AI summary
A method for determining a temperature characteristic of an electrochemical cell assembly includes (1) sensing a first voltage via one or more thermistors electrically coupled to the electrochemical cell assembly while loading circuitry electrically coupled to the thermistors is deactivated, (2) sensing a second voltage via the one or more thermistors while the loading circuitry is activated, and (3) determining the temperature characteristic of the electrochemical cell assembly at least partially from the first and second voltages.