Battery Pack Protection Circuit With Photocoupler Fast Shutoff
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Solution Overview
Problem
Existing battery protection systems face challenges in quickly and efficiently managing high short-circuit currents, which can lead to damage due to delayed transistor turn-off times and increased power consumption from using charge pump circuits for control signals.
Innovation Solution
A battery protection device incorporating a photocoupler that quickly turns off the transistor by emitting light to disconnect the control terminal, reducing power consumption and enhancing protection against high short-circuit currents, while a switch control circuit and driving circuit manage the transistor's on/off states based on current thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a charge pump circuit is used to generate control signals for the transistor, then the transistor can be controlled to turn on/off, but power consumption increases
Solution Approach 1:
The patent extracts the charge pump circuit from the system and replaces it with a photocoupler-based control mechanism. The photocoupler uses optical isolation to control the transistor without requiring a charge pump, thereby eliminating the high power consumption associated with charge pump operation while maintaining reliable transistor control.
Solution Approach 2:
The patent introduces a photocoupler as an intermediary device between the control signal source and the transistor. The photocoupler uses light as a mediator to transfer control signals without direct electrical connection, avoiding the need for a charge pump circuit and significantly reducing power consumption while maintaining control reliability.
2Reliability
If a conventional control circuit is used to turn off the transistor during short-circuit conditions, then the control signal can be generated, but the transistor turn-off time is delayed
Solution Approach 1:
The patent implements preliminary action by using the photocoupler to pre-establish a fast turn-off pathway for the transistor. When a short-circuit condition is detected, the photocoupler immediately activates to force the transistor off, bypassing the slower conventional control circuit response time and achieving rapid protection.
Solution Approach 2:
The patent replaces the conventional electrical control mechanism with an optical control mechanism using a photocoupler. This substitution enables faster response times because the optical signal can be activated immediately upon detecting abnormal conditions, eliminating the delays inherent in conventional electrical control circuits.
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 solution effectively minimizes power consumption and ensures rapid protection against high short-circuit currents by using a photocoupler to quickly turn off the transistor, thereby preventing damage to the battery pack.
Implementation Method 1
a photocoupler connected to a control terminal of the first transistor, the photocoupler being turned on or turned off according to the second control signal, and turning off the first transistor if the photocoupler is turned on
Data Source
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AI summary
A battery protection device (200) includes a first transistor (M1), a switch control circuit (210), a controller (240), and a photocoupler (230). The first transistor (M1) is connected between one of the pack terminals (P+, P-) of a battery pack (10a) and a battery module (100) and controls a current flow between the pack terminals (P+, P-) and the battery module (100). The switch control circuit (210) outputs a first control signal (S1) for turning on or turning off the first transistor (M1). The controller (240) outputs a second control signal (S2). The photocoupler (230) is connected to a control terminal of the first transistor (M1), is turned on or turned off according to the second control signal (S2), and turns off the first transistor (M1) if turned on.