Bypass Electrical Path Heater for Battery Thermal Management
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Solution Overview
Problem
Secondary batteries face challenges in low-temperature environments, where increased internal resistance leads to voltage variations, premature reaching of charge upper or discharge lower limit voltages, and reduced charging and output performance, making them unsuitable for emergency power sources like aircraft.
Innovation Solution
A battery system with a protection circuit featuring a bypass electrical path and a heater, where current diversion through the bypass path generates heat to reduce internal resistance and maintain optimal charging and output performance, even in low-temperature conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a bypass electrical path is provided to prevent overcharging, then battery safety is improved, but in low-temperature environments the battery still cannot be sufficiently charged due to increased internal resistance
Solution Approach 1:
The bypass electrical path is designed to serve dual functions: (1) preventing overcharging by diverting current when voltage reaches the upper limit, and (2) heating the battery in low-temperature environments to reduce internal resistance and enable sufficient charging. This multi-functional design resolves the contradiction by making the same structural element beneficial for both safety and charging performance under different conditions.
Solution Approach 2:
The system changes the temperature parameter of the battery by utilizing the bypass path to generate heat when needed. In low-temperature conditions, the bypass path allows current flow that generates thermal energy, raising the battery temperature and reducing internal resistance, thereby improving charging performance without compromising the overcharging protection function.
2Power
If multiple secondary batteries are connected in series to increase power output, then power capability is improved, but variations in internal resistance between batteries cause greater voltage variations during charging
Solution Approach 1:
The battery system is divided into independent modules, each with its own bypass electrical path and protection circuit. This segmentation allows each battery to be managed independently, with the bypass path for each battery able to divert current or generate heat according to that specific battery's needs, thereby reducing the impact of internal resistance variations across the series-connected system.
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 prevents overcharging, ensures sufficient charging and output performance, and maintains battery health by efficiently managing heat and current distribution across multiple batteries connected in series.
Implementation Method 1
the bypass electrical path includes a heater that generates heat using the current flowing through the bypass electrical path
Data Source
AI summary
A battery system is provided that can prevent overcharging during charging, and that can demonstrate appropriate charging performance and output performance of a secondary battery even when the battery system is used in a low-temperature environment. The battery system includes a secondary battery and a protection circuit. The protection circuit includes a bypass electrical path that connects an upstream-side main electrical path that is connected to a positive terminal of the secondary battery to a downstream-side main electrical path that is connected to a negative terminal of the secondary battery. The battery system is configured so that, when the voltage of the secondary battery exceeds a predetermined voltage during charging, current flowing through the secondary battery decreases while current flowing through the bypass electrical path increases, and when the voltage of the secondary battery falls below the predetermined voltage during charging, the current flowing through the secondary battery increases while the current flowing through the bypass electrical path decreases. The bypass electrical path includes a heater that generates heat using the current flowing through the bypass electrical path, and the heater is arranged adjacent to or in close contact with the secondary battery so as to impart a thermal effect to the secondary battery.