Battery Temperature Model Dynamic Time Constant
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Solution Overview
Problem
Existing methods for determining the storage temperature of vehicle rechargeable batteries using a temperature model often provide incorrect initial values due to self-heating dynamics and thermal equilibrium issues, leading to inaccurate battery temperature readings.
Innovation Solution
The method involves reducing or setting the time constant to zero for a predefined period after startup, linking the storage temperature to the measured correlation temperature until thermal equilibrium is established, and using a mathematical temperature model to account for thermodynamic inertia and correction variables.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the time constant is reduced or set to zero for a predefined period after startup, then the accuracy of storage temperature determination is improved by reducing deviations from actual values, but the complexity of the temperature model increases due to dynamic time constant adjustment
Solution Approach 1:
The time constant is made dynamic rather than fixed, allowing it to be reduced or set to zero during a predefined startup period and then restored to its normal value. This dynamic adjustment enables the temperature model to adapt to different operational phases, improving measurement accuracy during the critical startup period when thermal equilibrium has not yet been established.
Solution Approach 2:
The time constant parameter is temporarily modified during the predefined period after startup. By changing this key parameter of the temperature model, the system can better track the correlation temperature during the transient phase when the electronics are heating up, thereby improving the accuracy of storage temperature determination without permanently increasing model complexity.
2Productivity
If the first measured correlation temperature is used as the initial value in the temperature model, then the model can be initialized quickly, but the storage temperature is incorrectly determined due to self-heating dynamics and lack of thermal equilibrium
Solution Approach 1:
The system performs a preliminary action by reducing or setting the time constant to zero during the predefined startup period. This preliminary adjustment prepares the temperature model to correctly process the initial temperature measurements before thermal equilibrium is established, preventing incorrect storage temperature determination while maintaining quick initialization.
Solution Approach 2:
The invention applies preliminary anti-action by counteracting the self-heating effect of the electronics during startup. By temporarily modifying the time constant, the system compensates for the temperature difference between the correlation location (electronics) and storage location (battery), preventing the propagation of erroneous initial values through the temperature model.
3Reliability
If the time constant is reduced during startup, then the storage temperature follows the correlation temperature more closely during thermal transient, but the model becomes more sensitive to measurement noise
Solution Approach 1:
The reduced time constant is applied periodically or temporarily only during the predefined startup period when thermal equilibrium has not yet been established. After this period, the time constant is restored to its normal value. This time-limited application ensures that the benefits of improved thermal tracking are achieved only when needed, while minimizing the impact on measurement stability during normal 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 significantly reduces deviations in determined storage temperatures from actual values, improving accuracy and correcting for self-heating and thermal equilibrium errors, thereby enhancing battery condition assessment and charging reliability.
Implementation Method 1
The (unreduced) time constant of the temperature model, which takes into account the temporal correlation of the correlation and the storage temperature, is dominated by the thermodynamic inertia of the electrical storage.
Implementation Method 2
The electrical storage device and a measuring device for measuring the correlation temperature at the correlation location form a thermodynamic equilibrium system in which the storage location and the correlation location are thermally connected to one another.
Data Source
Figure 1~2
AI summary
The invention relates to a method for determining the storage temperature of an electrical storage device, in particular a rechargeable vehicle battery, at a storage location. This method involves determining a correlation temperature at a correlation point and calculating the storage temperature by inputting the correlation temperature as an initial value into a temperature model that takes into account the divergence between the storage location and the correlation point. The temperature model considers the temporal correlation between the correlation and storage temperatures by means of a time constant. The invention further relates to a corresponding device. Within a predefinable time interval, starting from the initial time, the time constant is reduced or set to zero.