Battery Pack Input Output Control System Internal Temperature Estimation
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Solution Overview
Problem
Existing battery pack systems fail to accurately estimate internal temperatures, leading to insufficient limitations on input/output, which can result in overheating and potential smoke issues due to variations in unit cell internal resistances and sensor measurement errors.
Innovation Solution
A battery pack input/output control system that estimates maximum internal temperature by accounting for ambient temperature, internal resistance variations, sensor contact state differences, and temperature detection errors, using multiple sensors to limit input/output based on these factors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a limited number of sensors are used to monitor battery surface temperature, then device complexity is reduced, but measurement precision deteriorates due to variations in unit cell internal resistances and sensor measurement errors
Solution Approach 1:
The patent introduces an intermediary estimation mechanism that uses detected surface temperature, current value, and pre-stored internal resistance data to calculate estimated internal temperature. This intermediary calculation bridges the gap between limited surface measurements and the need for accurate internal temperature assessment, allowing the system to maintain low complexity while achieving high measurement precision through computational compensation
Solution Approach 2:
The system changes parameters by incorporating current value as an additional input parameter and using pre-stored internal resistance data corresponding to different charge/discharge states. By changing from direct temperature measurement alone to a multi-parameter estimation approach (surface temperature + current value + internal resistance characteristics), the system compensates for sensor limitations and achieves accurate internal temperature estimation without adding physical sensors
2Device complexity
If temperature monitoring is based only on surface temperature, then device complexity is reduced, but reliability deteriorates due to insufficient limitation of battery input/output
Solution Approach 1:
The patent implements a feedback mechanism where the estimated internal temperature is continuously fed back to the control system to determine appropriate battery input/output limitations. The system stores temperature limitation values corresponding to different estimated internal temperatures and uses this feedback to dynamically adjust charging/discharging limits, ensuring reliable battery protection while maintaining simple surface-only sensing
Solution Approach 2:
The system performs preliminary action by pre-storing internal resistance data and temperature limitation values before actual battery operation. This pre-computed data allows the system to quickly and reliably determine safe operating limits based on real-time conditions without complex real-time calculations, ensuring battery safety while keeping the monitoring system simple
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 system effectively limits battery pack input/output to prevent overheating and smoking by accurately estimating internal temperatures, considering variations in internal resistances and sensor errors, thus ensuring safer operation.
Implementation Method 1
a plurality of battery temperature sensors are provided, and a surface temperature of the battery pack is detected by the battery temperature sensors
Implementation Method 2
a maximum internal temperature of the battery pack is estimated by adding a sum of the battery inside-outside temperature difference and an internal resistance-dependent temperature difference to a maximum value of the detected surface temperature
Data Source
AI summary
A controller 50 for estimating a maximum internal temperature of a battery pack 14 processes battery pack input/output limitations. The controller 50 estimates: a difference between a surface temperature and an internal temperature of the battery pack 14; a temperature difference that is dependent on different internal resistances of unit cells 12; a temperature difference that is dependent on contact states of a plurality of temperature sensors 32 with the battery pack 14; and a temperature difference that is dependent on different detection characteristics between the temperature sensors 32. The controller 50 further limits the input/output electric power of the battery pack 14 based on the estimated maximum internal temperature.