Power Supply Circuit Protection Device for Electric Vehicles
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Solution Overview
Problem
Existing power supply circuit protection devices face challenges in simultaneously protecting the power supply circuit during both driving and charging of electric vehicles, particularly when dealing with the high current loads associated with rapid and ultra-rapid charging, as the current loads during driving and charging differ significantly, making it difficult to effectively manage overcurrents.
Innovation Solution
A power supply circuit protection device that includes a relaying device, a fuse device with a first and second fuse, and a control device. The fuse device has a switching mechanism that alternates between the first and second fuses based on the operational mode, with the second fuse having a harder blowing characteristic than the first fuse, allowing for effective protection during high current loads during charging and driving. The relaying device includes separate relays for switching circuits, and the control device manages the switching mechanism to disconnect the first circuit during charging and connect the second circuit, ensuring safety and protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single fuse is used for both driving and charging circuits, then the device complexity is reduced, but the reliability of overcurrent protection deteriorates because the fuse cannot simultaneously protect against different current load conditions
Solution Approach 1:
The power supply circuit is segmented into two separate protection paths: a first fuse (201) for the driving circuit and a second fuse (202) for the charging circuit. Each fuse is specifically configured for its designated circuit's current characteristics, allowing independent optimization of protection parameters without compromising the other circuit.
Solution Approach 2:
The fuse switching mechanism (203) dynamically switches between the first and second fuses based on operational mode (driving or charging). The control device (30) activates the appropriate fuse according to real-time operational conditions, enabling adaptive protection that responds to changing current load requirements.
2Reliability
If the fuse blowing characteristic is set for normal driving current, then driving circuit protection is adequate, but the fuse may blow prematurely during rapid charging due to higher current loads
Solution Approach 1:
The protection system is divided into two specialized fuses with different blowing characteristics. The first fuse (201) has a blowing characteristic optimized for driving current levels, while the second fuse (202) has a harder blowing characteristic designed to withstand the higher current loads of rapid charging, preventing premature blowing during charging operations.
Solution Approach 2:
The fuse blowing current parameter is changed based on operational mode. During driving, the system uses a fuse with lower blowing current threshold appropriate for driving loads. During charging, the system switches to a fuse with higher blowing current threshold that accommodates charging current levels without premature activation.
3Productivity
If the fuse blowing characteristic is set for high current charging, then charging circuit protection is adequate, but the fuse may not provide sufficient protection during normal driving with lower current loads
Solution Approach 1:
The system employs separate fuses for different operational modes. The second fuse (202) with harder blowing characteristic is dedicated to charging circuit protection, enabling high current charging capability. The first fuse (201) with softer blowing characteristic is dedicated to driving circuit protection, ensuring sensitive protection for normal driving operations.
Solution Approach 2:
The fuse configuration dynamically adapts to operational requirements. During charging operations, the second fuse with higher current tolerance is activated to support rapid charging. During driving operations, the first fuse with lower current threshold is activated to provide sensitive protection against overcurrent conditions in the driving circuit.
4Device complexity
If circuits remain connected during mode switching, then the switching mechanism is simpler, but safety deteriorates due to potential energization and short circuits
Solution Approach 1:
The control device (30) implements preliminary disconnection of circuits before switching between driving and charging modes. By disconnecting the currently active circuit before connecting the new circuit, the system prevents simultaneous energization of both circuits, eliminating the risk of short circuits during mode transitions.
Solution Approach 2:
The switching mechanism (203) and relay (18) perform preliminary disconnection actions before connection actions. The control device ensures that the circuit to be deactivated is fully disconnected and de-energized before the circuit to be activated is connected, maintaining safety throughout the transition process.
Data Source
AI summary
A power circuit protection device for a vehicle including a storage device, a drive motor, and a charging terminal includes a relaying device, a fuse device and a control device. The relaying device alternatively forms a first circuit that connects the storage device and the driving motor, and a second circuit that connects the storage device and the charging terminal. The fuse device is interposed between the storage device and the relaying device. The fuse device includes a first fuse, a second fuse having a fusing characteristic that is harder to blow than that of the first fuse, and a switching mechanism. The control device controls the switching mechanism such that the second fuse is connected to the power storage device when the control device controls the relaying device so that the second circuit is connected to the control device upon receiving a predetermined charging request.