Multi-Pack Battery System with Mutually-Exclusive 3-Way Contactor
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Solution Overview
Problem
Current electric powertrain systems for battery electric vehicles and hybrid electric vehicles face challenges in efficiently managing high-power charging and propulsion requirements, particularly in switching between different voltage configurations to optimize component usage and reduce electrical failure modes.
Innovation Solution
A reconfigurable multi-pack battery system with three-way/two-position contactors allows for selective connection of battery packs in series or parallel configurations, enabling flexible voltage operations and reducing the risk of electrical faults by ensuring mutually-exclusive series and parallel connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple two-way/two-position contactors are used to switch between series and parallel battery configurations, then the battery system can achieve flexible voltage operations, but the component count and circuit control complexity increase
Solution Approach 1:
The patent combines the functions of multiple two-way contactors into a single three-way/two-position contactor. This single contactor has three terminals (first terminal connected to battery pack positive electrode, second terminal for series connection, third terminal for parallel connection) that can selectively connect between series and parallel configurations, thereby reducing component count while maintaining configuration flexibility
Solution Approach 2:
The three-way/two-position contactor serves multiple functions: it acts as a series connection switch, a parallel connection switch, and provides isolation functionality all in one device. This multi-functional design eliminates the need for separate contactors for each function, reducing overall system complexity
2Reliability
If standard two-way contactors are used for battery pack switching, then the circuit design is simpler, but the risk of electrical failure modes such as welded contacts increases
Solution Approach 1:
The patent converts the potential harm of contactor failure into a beneficial safety feature by designing the three-way contactor so that terminal 2 and terminal 3 are physically isolated and cannot be simultaneously connected. This structural design ensures that even if welding occurs, it cannot create a short circuit between series and parallel connection paths, transforming a potential failure mode into a fail-safe mechanism
Solution Approach 2:
The contactor structure segments the connection paths into physically isolated terminals (terminal 2 for series, terminal 3 for parallel) that cannot interfere with each other. This segmentation prevents cross-contamination between different connection modes and eliminates certain failure modes that could occur with integrated switching mechanisms
Data Source
AI summary
A battery system for a motor vehicle or other system includes a voltage bus with positive and negative bus rails, and first and second battery packs. The battery packs are arranged between and connected to rails. High-voltage switches are collectively configured to selectively interconnect the battery packs in a series or parallel battery arrangement. The switches include a pair of mutually-exclusive three-way/two-position contactors each having a series connection position and parallel connection position corresponding to the respective series and parallel battery arrangements. An electric powertrain includes an electrical load connected to the battery system, and a controller coupled to the switches. In response to a battery mode selection signal, the controller selectively transitions the contactors from the series connection position to the parallel connection position, or vice versa. A motor vehicle includes road wheels, a body, and the electric powertrain.