Battery Cell Tab Temperature Estimation for Power Derating
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
It is challenging to directly measure the temperature of a battery cell tab due to design and packaging constraints, making it difficult to control the temperature effectively in electric vehicle battery packs, where the tab is prone to reaching unsafe temperatures first.
Innovation Solution
A method and system that predict the tab temperature using dynamic thermal models and Kalman filters based on measurements from other locations within the battery module, allowing for power derating when the tab temperature exceeds a threshold to prevent overheating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a temperature sensor is placed directly at the battery cell tab to measure tab temperature, then measurement precision is improved, but device complexity and difficulty of manufacture worsen due to design and packaging constraints
Solution Approach 1:
The patent uses an intermediary approach by placing temperature sensors at accessible locations (cell body, tab attachment point, bus bar) rather than directly at the tab. A thermal model then acts as a mediator to calculate the tab temperature from these indirect measurements, resolving the contradiction between measurement precision and device complexity
Solution Approach 2:
Instead of directly measuring tab temperature, the system creates a thermal model that copies the thermal behavior of the tab based on measurements from other locations. This virtual copy allows accurate temperature estimation without physical sensor placement at the difficult-to-access tab location
2Productivity
If power is increased to meet vehicle demand, then productivity is improved, but temperature increases causing thermal damage and reducing reliability
Solution Approach 1:
The system continuously monitors temperature at multiple locations and uses this feedback to dynamically adjust power delivery. When tab temperature approaches unsafe levels, the system reduces power output to prevent thermal damage, resolving the contradiction between productivity and reliability
Solution Approach 2:
The patent implements dynamic power management where the maximum allowable power is continuously adjusted based on real-time temperature conditions. This allows the system to operate at high power when safe and reduce power when temperature limits are approached, balancing productivity and reliability
3Measurement precision
If multiple temperature sensors are added to monitor tab temperature directly, then measurement precision is improved, but manufacturing cost and device complexity increase
Solution Approach 1:
The temperature sensors are placed at locations that serve multiple functions: monitoring cell body temperature, tab attachment point temperature, and bus bar temperature. This multi-functional sensor placement achieves comprehensive temperature monitoring without requiring additional sensors, resolving the contradiction between measurement precision and ease of manufacture
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 approach effectively controls the battery cell temperature, preventing thermal damage and extending the life of the battery pack by accurately estimating tab temperatures without direct sensing, ensuring safe operation and efficient power management.
Implementation Method 1
the tab is in thermal contact with a bus and the bus is in thermal contact with a heat sink, and the dynamic thermal model determines a state of the battery cell based on a thermal heating of the tab, the bus and the heat sink due to the current through the tab
Implementation Method 2
A Kalman filter is applied to the state of the battery cell determined using the dynamic thermal model to determine the tab temperature
Implementation Method 3
thermal heating of the tab, the bus and the heat sink due to the current through the tab
Data Source
AI summary
A vehicle includes a system operating a method of controlling a temperature at a battery cell of the vehicle. The system includes the battery cell, a temperature sensor and a processor. The battery cell has a tab for flow of current to and from the battery cell. The temperature sensor is configured to measure a cell temperature of the battery cell at a location away from the tab. The processor is configured to predict a tab temperature from the cell temperature, and control a power supplied to a load from the battery cell based on the tab temperature.