Battery Control Circuit Temperature Estimation for Natural Cooling
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Solution Overview
Problem
Existing battery management systems, particularly in naturally-cooled battery systems, face challenges in maintaining battery cell temperatures within the use limit due to insufficient cooling performance, leading to frequent shutdowns and reduced utilization, as they fail to account for dynamic changes in charging/discharging currents and varying operational and ambient conditions.
Innovation Solution
A battery system with a control circuit that performs multiple temperature rising estimations based on battery temperature, charging/discharging current, and time window, selecting a current limit that prevents the battery cell temperature from exceeding the use limit by calculating optimal charging/discharging current limits using a battery state calculation unit, temperature modeling unit, and optimal condition calculation unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a cooling system is used to control battery cell temperature, then the battery cell temperature can be kept within the use limit, but the system size and weight increase
Solution Approach 1:
The patent removes the cooling system from the battery system, transitioning from a forced cooling approach to a natural cooling approach. This extraction of the cooling system directly reduces system weight and size while the invention compensates through improved temperature management control methods that predict and prevent temperature exceedances through multiple future estimations.
2Weight of stationary object
If the cooling system is reduced or removed for weight reduction, then system weight decreases, but cooling performance becomes insufficient and battery cell temperature may exceed the use limit
Solution Approach 1:
The patent performs multiple temperature rising estimations for future time points before actually charging/discharging the battery. By predicting future battery cell temperatures at multiple future time points based on different current values, the system proactively identifies current limits that will keep temperature within the use limit, preventing temperature exceedances before they occur.
Solution Approach 2:
The patent implements a feedback control mechanism where the control circuit continuously monitors actual battery cell temperature and compares it with predicted future temperatures. Based on this feedback, the control circuit adjusts the charging/discharging current to multiple future time points to ensure temperature remains within the use limit, creating a closed-loop control system that compensates for the absence of active cooling.
3Reliability
If the battery system stops the charging/discharging process when temperature reaches the limit value, then battery cell temperature safety is ensured, but the utilization of the battery system is reduced
Solution Approach 1:
The patent performs multiple temperature rising estimations for future time points before actually charging/discharging the battery at high current. By predicting future battery cell temperatures and identifying safe current limits in advance, the system can operate at higher currents for longer durations without risking temperature exceedances, thereby reducing unnecessary shutdowns and improving utilization while maintaining safety.
4Device complexity
If PTL 1's temperature rising estimation method is used, then the battery cell temperature control is simplified, but the estimation accuracy is insufficient because it does not consider future charging/discharging current changes
Solution Approach 1:
The patent divides the temperature rising estimation into multiple discrete future time points (first future time point, second future time point, etc.). Instead of a single estimation, the control circuit performs separate temperature rising estimations for each future time point, allowing for more precise tracking of temperature evolution over time and better identification of safe operating current limits.
Solution Approach 2:
The patent implements dynamic temperature rising estimations that adapt to changing operating conditions. The control circuit continuously updates future temperature predictions based on actual battery state and adjusts future current limits dynamically. This dynamic approach captures the time-varying nature of battery thermal behavior and external conditions, improving estimation accuracy compared to static methods.
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 ensures the battery cell temperature remains within the use limit, reduces the frequency and duration of shutdowns, and maximizes battery utilization by accurately controlling the charging/discharging process, even in unpredictable conditions.
Implementation Method 1
a battery management system which controls a charging/discharging process to secure a battery cell temperature to be equal to or less than a maximum value
Data Source
AI summary
Provided is a battery system in which a battery cell does not exceed a use limit temperature, and a time taken for returning to the charging/discharging process is shortened even if a frequency for the battery system to stop a charging/discharging process is reduced and the charging/discharging process is stopped. The battery system disclosed in the invention includes a plurality of battery cells and a control circuit which controls a charging/discharging current of the battery cell. The control circuit performs a plurality of temperature rising estimations on the basis of a battery temperature, a charging/discharging current, and a time width of a time window. The control circuit selects the charging/discharging current corresponding to a temperature rising estimation in which the temperature of the battery cell does not exceed a use limit temperature among the temperature rising estimations.