Secondary Battery Control Circuit Using Self-Heating
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Solution Overview
Problem
Lithium-ion secondary batteries face performance issues at low and high temperatures, with reduced functionality below freezing and potential shortening of lifespan at elevated temperatures, necessitating a control system that maintains stability across varying environmental conditions.
Innovation Solution
A control system for secondary batteries that employs multiple batteries with different operating temperature ranges, where a low-temperature battery acts as a heat source to maintain other batteries within their operational range, using a temperature sensing terminal and a control circuit to manage heating and monitor voltage and temperature, ensuring safe operation and extended functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single type of secondary battery is used, then the device complexity is low, but the battery cannot maintain stable performance across different temperature conditions
Solution Approach 1:
The battery system is divided into multiple battery units, each optimized for specific temperature ranges. This segmentation allows each unit to operate within its optimal performance window, ensuring reliable operation across varying environmental conditions while maintaining manageable system complexity through modular design.
Solution Approach 2:
Different battery units are assigned different operational characteristics suited to their intended temperature environments. This local quality approach ensures that each battery operates under conditions where it exhibits its best performance characteristics, thereby improving overall system reliability without requiring complete redesign of the entire battery system.
2Reliability
If multiple types of secondary batteries are used for temperature control, then the battery performance stability across temperatures is improved, but the device complexity increases
Solution Approach 1:
Multiple battery units with different temperature optimizations are combined into a single integrated system. This merging allows the system to leverage the strengths of each battery type while presenting a unified interface and control mechanism, thereby improving temperature-dependent reliability without proportionally increasing operational complexity.
Solution Approach 2:
The multi-battery system is designed to perform multiple functions: each battery unit can independently operate across different temperature ranges, and they can work together to provide stable performance across the full temperature spectrum. This multi-functionality allows a single system to handle various temperature conditions without requiring separate specialized systems.
3Productivity
If the battery operates at low temperatures, then the charging and discharging performance is reduced, but the battery can still function with limited efficiency
Solution Approach 1:
The system performs preliminary heating of the battery units before charging or discharging operations at low temperatures. This preliminary action ensures that the battery reaches its optimal operating temperature range before being subjected to high-rate charging or discharging, thereby maintaining high productivity even in cold environmental conditions.
4Reliability
If the battery operates at high temperatures, then the lifetime is shortened and abnormalities may occur, but the battery can still operate with reduced lifespan
Solution Approach 1:
The system incorporates temperature monitoring and control mechanisms that provide feedback to the battery management system. When high temperatures are detected, the system adjusts operating parameters or activates cooling measures to prevent thermal runaway and extend battery lifetime, thereby maintaining reliability even when environmental temperatures are elevated.
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
The system effectively maintains secondary battery performance across a wide temperature range, ensuring safe and efficient operation by detecting abnormalities and providing early warnings, thus enhancing safety and longevity.
Implementation Method 1
when the ambient temperature is low, some of second secondary batteries are heated by electric power of a first secondary battery
Data Source
AI summary
A control system for a secondary battery which is less affected by the ambient temperature by performing temperature control of the secondary battery is provided. A control system for a secondary battery which is less affected by the ambient temperature and in which a plurality of kinds of secondary batteries are used for temperature control is achieved and mounted on a vehicle. Specifically, when the ambient temperature is low, some of second secondary batteries are heated by self-heating of a first secondary battery. After the second secondary batteries are sufficiently heated, the rest of the second secondary batteries are heated in stages by self-heating of the some of the second secondary batteries whose temperature has been increased. Whether the some or all of the second secondary batteries are sufficiently heated can be confirmed if the temperatures of a plurality of temperature sensors provided in the second secondary batteries are within the operating temperature range of the second secondary batteries. For example, with the use of a temperature sensing terminal (T terminal) for a temperature sensor, a switch is closed when the internal temperature of the secondary batteries is out of the operating temperature range.