Internal Temperature Determination in Energy Storage Devices
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Solution Overview
Problem
Existing electrochemical energy storage devices in motor vehicles face challenges in accurately determining internal temperatures, leading to inefficient operation and accelerated aging due to reliance on surface temperature measurements, which do not reflect the actual internal conditions.
Innovation Solution
A method utilizing a thermal model in a control device to simulate and determine the internal temperature of the energy storage device, eliminating the need for direct temperature sensors, by accounting for thermal capacitances and resistances, and incorporating a cooling device's thermal dissipation loss, allowing for precise temperature regulation and status recognition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a temperature sensor is placed on the surface of the housing or on a single storage cell, then the temperature can be measured with simple construction, but the measured temperature does not correspond to the actual internal temperature of the electrochemical energy storage device
Solution Approach 1:
The patent creates a thermal model that is a simplified representation of the actual thermal system. The model includes thermal capacitances representing different components (cell winding, housing, cooling device) and thermal resistances representing heat transfer paths. This virtual copy allows accurate internal temperature determination without physical intrusion into the storage cells.
Solution Approach 2:
The patent introduces a cooling device as an intermediary element with a temperature sensor. The cooling device is thermally coupled to the storage cells, allowing indirect measurement of internal temperature through the cooling device's temperature, which reflects the thermal state of the storage cells without requiring direct sensor placement inside the cells.
2Measurement precision
If a direct measurement of the internal temperature of a cell chamber is performed, then the actual internal temperature can be determined, but the manufacturing process becomes more involved and additional sealing measures are required
Solution Approach 1:
Instead of physically accessing the cell chamber for direct measurement, the patent creates a thermal model that replicates the thermal behavior of the internal components. The model uses thermal capacitances and resistances to simulate heat transfer, allowing accurate temperature determination through calculation rather than physical measurement inside the sealed cell chambers.
Solution Approach 2:
The cooling device serves as an intermediary that provides access to internal temperature information without requiring penetration of the sealed cell chambers. The temperature sensor is placed in the cooling device, which is externally accessible and thermally coupled to the storage cells, thereby maintaining sealing integrity while enabling temperature measurement.
3Temperature
If the operating temperature of the storage cells exceeds the upper temperature threshold, then the energy storage device can operate at higher temperatures, but accelerated aging results and the required operating life cannot be complied with
Solution Approach 1:
The patent implements a feedback control system that continuously monitors the internal temperature of storage cells using the thermal model and adjusts the cooling device operation accordingly. The control device compares the determined internal temperature with the upper temperature threshold and activates the cooling device when necessary to maintain temperature within safe operating limits, preventing accelerated aging and extending operating life.
Solution Approach 2:
The thermal model allows prediction of internal temperature trends before actual overheating occurs. By monitoring parameters such as ambient temperature, load conditions, and cooling device operation, the system can anticipate temperature rises and activate cooling measures in advance, preventing the storage cells from reaching dangerous temperature thresholds that would cause accelerated aging.
4Temperature
If the storage cells are operated below the lower temperature threshold, then the energy storage device can operate at lower temperatures, but the capacity of the cells is sharply reduced and efficient operation is not possible
Solution Approach 1:
The feedback control system monitors internal temperature and activates the heating device when the temperature approaches the lower threshold. By maintaining temperature above the lower threshold through active heating when needed, the system ensures that storage cells operate within the optimal temperature range for maximum capacity and efficiency, regardless of ambient temperature conditions.
Solution Approach 2:
The thermal model enables prediction of temperature drops that would cause the storage cells to approach the lower temperature threshold. The control device can activate heating measures in advance based on predicted temperature trends, ensuring that cells remain within the optimal operating temperature range and maintain high capacity and efficiency throughout operation.
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 enables more efficient and homogeneous operation of the energy storage device, minimizing the risk of temperature thresholds being exceeded, leading to extended lifespan and improved status estimation precision without the need for direct internal temperature measurement.
Implementation Method 1
accounting for thermal capacitances and resistances
Implementation Method 2
accounting for thermal capacitances and resistances
Implementation Method 3
incorporating a cooling device's thermal dissipation loss
Data Source
AI summary
A device is provided for determining the internal temperature of an electrochemical energy storage device, particularly for a motor vehicle. The internal temperature of a cell winding of the energy storage device is determined by calculation in a control device of the energy storage device by way of a thermal model for the energy storage device which is saved in the control device.