Battery Charger Internal Switch for Deep Discharge Protection
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Solution Overview
Problem
Existing deep discharge protection systems for lithium-ion batteries in on-board units face issues such as heating and startup difficulties due to the use of power MOS-transistors, which are costly and inefficient, and fail to prevent deep discharge during shipment and normal operation.
Innovation Solution
A system and method that utilize an internal switch within the battery charging unit to disconnect the battery when the voltage falls below a threshold, triggered either during production or when the battery is inserted, preventing deep discharge without the need for additional expensive switches, and automatically reconnects when an external energy source is available.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If power MOS-transistors are used as switches in deep discharge protection circuits, then the battery can be disconnected when voltage drops below threshold, but the transistor heats up due to voltage drop and additional costly components are required
Solution Approach 1:
The battery charging unit's internal switch automatically opens when the battery voltage drops below the threshold, using the charging unit's own resources to protect the battery without requiring external active components. The system serves itself by leveraging existing circuitry to perform the protection function.
Solution Approach 2:
The invention extracts the switching function from external power MOS-transistors and relocates it to the internal switch of the battery charging unit. This removes the need for additional expensive switches and reduces the overall system complexity while maintaining the protection function.
2Reliability
If power MOS-transistors are used as switches in deep discharge protection circuits, then the battery can be disconnected when voltage drops below threshold, but additional expensive switches are required
Solution Approach 1:
The battery charging unit's internal switch is designed to serve multiple functions: normal charging operation and deep discharge protection. By making this component multi-functional, the invention eliminates the need for dedicated external protection switches, reducing device complexity and cost.
Solution Approach 2:
The invention merges the deep discharge protection function with the existing battery charging unit by utilizing its internal switch. This consolidation combines what would traditionally be separate functions (charging and protection) into a single integrated unit, reducing the total number of components.
3Reliability
If the transistor disconnects the battery from the charging unit, then deep discharge is prevented, but the system does not easily start up again even when connected to vehicle battery
Solution Approach 1:
The system automatically restarts itself when the vehicle battery is connected. The internal switch of the battery charging unit closes automatically when charging conditions are met, eliminating the need for manual intervention or complex restart procedures. The system serves itself by leveraging the presence of the vehicle battery to restore normal operation.
4Ease of operation
If the battery is left connected in the device during shipment, then the device is ready for immediate use, but the battery may undergo deep discharge during transport
Solution Approach 1:
The deep discharge protection function is pre-configured and activated before the device is shipped. The internal switch of the battery charging unit is set to automatically open when voltage drops below the threshold, preventing deep discharge during transport while keeping the battery connected and ready for immediate use upon arrival.
Data Source
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AI summary
A system for deep discharge protection of a chargeable battery (1) in an electronic device comprises: a chargeable battery (1), which is configured to provide energy to a system (3), when operation of the electronic device is needed and no other energy source is available; a battery charging unit (2) with an internal switch (S2), wherein the battery charging unit (2) is coupled to the chargeable battery (1) and is configured to charge the chargeable battery (1); a deep discharge protection unit (4), which is configured to monitor a voltage of the chargeable battery (1) and disconnect the chargeable battery (1) from the system (3), when the battery voltage is lower than a given threshold voltage; and a transport mode unit (5), which is configured to trigger an opening of the internal switch (S2) of the battery charging unit (2), wherein the chargeable battery (1) is disconnected from the system (3) when the at least one internal switch (S2) is opened.