Semiconductor Battery Isolator for Hybrid Vehicle Systems
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Solution Overview
Problem
Existing battery systems for hybrid and electric vehicles rely on large, heavy, and unreliable electromechanical components, such as contactors, for disconnecting and charging, which are prone to faults and generate noise.
Innovation Solution
The use of bidirectionally blockable semiconductor switches, such as bipolar transistors or metal-oxide-semiconductor field-effect transistors, with diode bridges to create isolating devices that can switch currents independently of direction, replacing traditional electromechanical components and eliminating the need for pre-charging resistors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electromechanical contactors are used for disconnecting and charging battery strings, then the system can achieve electrical separation, but the components become large, heavy, and have high failure rates
Solution Approach 1:
The patent replaces electromechanical contactors with semiconductor switches (IGBTs or MOSFETs) that perform the same electrical disconnecting and charging functions without mechanical moving parts. This substitution eliminates the inherent mechanical failure modes, reduces weight, and improves reliability while maintaining the ability to electrically separate battery strings and control charging currents.
Solution Approach 2:
The invention changes the fundamental operating parameters of the disconnecting device by transitioning from electromagnetic actuation (contactors) to solid-state semiconductor switching. This parameter change enables the same electrical isolation function with dramatically reduced physical dimensions, weight, and failure rate, as semiconductor switches operate without mechanical contact or electromagnetic fields.
2Object-affected harmful factors
If electromechanical contactors are used for battery string disconnection, then electrical separation is achieved, but the components generate noise and occupy large space
Solution Approach 1:
The patent replaces electromechanical contactors with semiconductor switches that eliminate mechanical switching noise and electromagnetic interference. Solid-state switching occurs without physical contact or field collapse, dramatically reducing noise emissions while also shrinking the required installation space to a fraction of the original contactor size.
3Ease of operation
If traditional charging devices with precharging resistors are used, then charging currents can be limited, but the components become larger and more complex
Solution Approach 1:
The patent makes the semiconductor switch serve multiple functions: it acts as both the disconnecting device for electrical isolation and the charging device for current limitation. By controlling the switching timing and state, the same component performs both battery string disconnection and controlled charging of the DC link capacitor, eliminating the need for separate precharging resistors and reducing overall system complexity.
Solution Approach 2:
The invention merges the disconnecting device and charging device into a single integrated semiconductor switch. This consolidation combines the electrical isolation function and the controlled charging function into one component, reducing the number of parts, simplifying the circuit topology, and improving reliability by eliminating the interface between separate components.
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
This solution enhances reliability, reduces weight and volume, eliminates noise, and provides a more efficient and cost-effective means of disconnecting and charging battery systems, improving overall system performance and reducing fault rates.
Implementation Method 1
The separating device (140) comprises at least one bidirectionally blockable switching device with at least one semiconductor switch (150). A semiconductor switch (150) is arranged in the separator, in the current path of a battery string current. The separating device (140) is also designed to switch the current through the battery string independently of its current direction by switching the semiconductor switch (150).
Implementation Method 2
In a further very advantageous embodiment of the invention, a diode bridge comprised by the isolating device is assigned to the semiconductor switch comprised by a switching device of an isolating device according to the invention. The diode bridge is connected to the associated battery string and also to the associated semiconductor switch in such a way that a current flowing through the semiconductor switch always flows forward through the semiconductor switch, regardless of the direction in which the corresponding current flows through the associated battery string.
Data Source
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AI summary
The invention relates to a battery (11) having at least one battery string (20), wherein a plurality of battery modules (30) which can be connected in series and have in each case at least one battery cell are arranged in the battery string (20), wherein said battery string (20) can be activated between the battery string terminals (21, 22) allocated thereto by means of at least one separating device (140) associated with the battery string (20) or said battery string (20) can be decoupled from the battery string terminal (21, 22) allocated to it, and wherein the battery (11) is connectable to an electric motor. The separating device (140) is designed as a bidirectionally lockable switching device, wherein, in the separating device, a semiconductor switch (150) is arranged in the current path of a current flowing through the battery string (20), and the separating device (140) is further designed to switch the current through the battery string (20) independently from its current direction by switching the semiconductor switch (150).