Electric Circuit Interrupting Device for Electric Vehicles
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Solution Overview
Problem
Existing electric circuit interruption devices in electric vehicles, such as those described in WO 2014/065763 and EP 0 227 407 A2, either generate electric arcs or fail to completely disconnect the driving unit from the energy source, particularly in crash situations, and do not effectively manage battery discharge.
Innovation Solution
Integration of fuses with melting members and varistors in each conductor of the primary electric circuit, where varistors are heat-conductively connected to melting members and controlled by an autonomous electromagnetic switch to establish a secondary circuit for controlled interruption, avoiding undesired effects like arcs and ensuring complete disconnection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a classic resistor is used in the fuse, then the circuit can be interrupted, but electric arc is generated
Solution Approach 1:
The patent changes the electrical parameter of the resistor by using a varistor instead of a classic resistor. The varistor's resistance changes with voltage, allowing it to limit current and suppress electric arcs while still enabling circuit interruption. This parameter change resolves the contradiction between reliable circuit interruption and harmful arc generation.
Solution Approach 2:
The patent converts the potentially harmful electric arc into a beneficial effect by using the varistor's voltage-dependent resistance to control and limit the arc, transforming it into a controlled energy dissipation mechanism that protects the circuit without creating dangerous arcs.
2Object-generated harmful factors
If a varistor is used in the fuse, then electric arc is suppressed, but only one conductor can be interrupted
Solution Approach 1:
The patent divides the circuit protection into separate segments by placing fuses with varistors in each conductor independently. This segmentation allows each conductor to be interrupted separately while maintaining electric arc suppression in each segment, ultimately achieving complete circuit interruption when both conductors are protected.
Solution Approach 2:
The patent combines multiple fuses with varistors in each conductor to achieve complete circuit interruption. By merging the protection functions of individual fuses into a comprehensive system, the patent achieves both electric arc suppression and complete circuit disconnection.
3Reliability
If a fuse with melting member is used, then circuit interruption is achieved, but battery discharge is not intensive
Solution Approach 1:
The patent applies preliminary action by pre-positioning the varistor in heat-conductive relationship with the melting member. This preliminary arrangement ensures that when the varistor limits current, the controlled energy is already directed to heat the melting member, preparing for efficient circuit interruption and enabling intensive battery discharge without requiring additional energy conversion steps.
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 interrupts the electric circuit without generating arcs or sparks, ensuring complete disconnection of the driving unit from the energy source, including intensive battery discharge, thereby addressing the limitations of existing technologies.
Implementation Method 1
a varistor, the resistance of which is reciprocally correlated with voltage to which it is exposed
Implementation Method 2
a melting member, which is capable to interrupt an electric circuit extending there-through
Implementation Method 3
a resistor, in particular a voltage-dependent resistor, namely a varistor, the resistance of which is reciprocally correlated with voltage to which it is exposed, wherein said resistor is arranged adjacent to said melting member and therefore in a heat-conductive relationship with said melting member
Implementation Method 4
each of said varistors is electrically connected with a switch, which is adapted for establishing or interruption of electric contact between said varistors of both fuses
Data Source
Figure 1
AI summary
A primary electric circuit interrupting device, in particular for electric vehicles, provides that a fuse (3', 3") comprising a melting member (3 Γ, 31") and a varistor (32', 32") is integrated within each of two electric conductors (21, 22), by means of which each driving unit (1) is connected with each electric energy source (2). Each varistor (32', 32") in each fuse (3', 3") is arranged in electric contact and simultaneously also in a heat-conductive contact with each belonging melting member (3 Γ, 31"), and moreover, each varistor (32', 32") is electrically connected with a switch (4) intended for establishing or interrupting the electric interconnection between both varistors (32', 32") of said fuses (3', 3").