Antiparallel Load Switches for Parallel Battery Stability
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Solution Overview
Problem
The existing parallel connection of vehicle batteries in electrically driven motor vehicles is unstable due to varying open-circuit voltages, which can lead to inefficient charging and discharging, and requires expensive DC/DC converters to stabilize the system.
Innovation Solution
The use of electronic load switches arranged antiparallel to each other, along with field effect transistors and blocking diodes, allows for safe and efficient charging and discharging of batteries, eliminating the need for DC/DC converters and reducing power loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If DC/DC converters are used to stabilize the battery system, then system stability is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts and eliminates the DC/DC converter from the system by using antiparallel load switches that directly control each battery, removing the need for complex voltage conversion and stabilization equipment while maintaining system stability through simplified switching control
Solution Approach 2:
Instead of using active DC/DC converters to actively stabilize voltage differences, the patent inverts the approach by using antiparallel switches that passively manage battery connections, allowing the batteries themselves to stabilize through their inherent characteristics and control logic
2Stability of the object's composition
If DC/DC converters are used to stabilize the battery system, then system stability is improved, but manufacturing cost increases
Solution Approach 1:
The patent replaces expensive DC/DC converters with inexpensive antiparallel load switch configurations, using simple, cost-effective components that can be manufactured at lower cost while achieving the same stabilization function through clever circuit topology
Solution Approach 2:
The patent uses identical antiparallel switch configurations for each battery, creating a standardized, replicable module that simplifies manufacturing and reduces costs through economies of scale and standardized production processes
3Reliability
If DC/DC converters are used, then voltage differences are compensated, but power loss increases
Solution Approach 1:
The patent enables the battery system to self-regulate voltage differences through the antiparallel switch configuration, where the batteries automatically balance each other through controlled charging and discharging cycles without requiring external power conversion equipment that would incur losses
Solution Approach 2:
The patent maintains continuous, efficient energy transfer between batteries and the electrical load through direct switching connections, eliminating the intermittent energy conversion and loss associated with DC/DC converter operation while maintaining continuous voltage compensation
4Reliability
If DC/DC converters are used, then battery charging is stabilized, but device weight increases
Solution Approach 1:
The patent removes the heavy DC/DC converter equipment from the vehicle system by implementing a lightweight switching-based battery management approach using antiparallel load switches, significantly reducing overall system weight while maintaining charging stability
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 enables cost-effective, efficient, and stable operation of electric vehicles by optimizing the connection of high-voltage batteries in parallel, reducing weight and power loss, and enhancing overall system efficiency.
Implementation Method 1
the two power branches arranged antiparallel to one another each have an IGBT and a blocking diode. The respective modules can thus be charged and discharged, with an undesired and parasitic current flow between battery modules with different states of charge or voltages being able to be effectively avoided.
Implementation Method 2
The use of such a field effect transistor unit can lead to a significant reduction in the power loss occurring at the respective IGBTs.
Data Source
Figure 1~2
Figure 3~4
AI summary
The invention relates to an electrically drivable motor vehicle comprising at least two vehicle batteries (2, 2') that can be connected in parallel and an electronic circuit arrangement (3) having a plurality of load interrupter switches (S1, S2) that correspond to the plurality of vehicle batteries (2, 2'), said load interrupter switches (S1, S2) being used to connect the vehicle batteries (2, 2') through to an electrical consumer (4) individually or together. According to the invention, each load interrupter switch (S1, S2) has two power branches (6, 6') that are arranged antiparallel to each other.