Battery Assembly Ground Reference Stabilization
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Solution Overview
Problem
Existing multi-cell battery arrangements for electrically drivable motor vehicles with 250-400V voltage levels are not readily available and cost-effective, and they lack a stable ground reference due to the motor vehicle body not acting as a return conductor.
Innovation Solution
A battery arrangement with two lithium-ion batteries connected in series, featuring a separate insulated return conductor and a connection point to the ground potential, stabilized by a capacitor or high-resistance connection to manage high-frequency and DC components, ensuring a floating electrical potential.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional automotive batteries with 250-400V voltage are used, then cost and availability are improved, but the battery voltage is insufficient for higher power electric drive motors
Solution Approach 1:
The battery system is segmented into multiple individual batteries (e.g., two 12V batteries) that are connected in series to achieve the required higher voltage (24V or 400V). This allows using conventional, cost-effective battery units while achieving the necessary voltage level for high-power electric drive motors.
2Device complexity
If the vehicle body is used as ground potential for the negative conductor, then device complexity is reduced, but the battery assembly lacks a stable ground reference causing potential drift
Solution Approach 1:
A dedicated ground connection (chassis ground) is introduced as an intermediary element that provides a stable reference potential. This ground connection is electrically connected to the battery assembly's negative terminal, creating a fixed reference point that prevents potential drift while maintaining system reliability.
3Reliability
If a separate negative terminal with electrically insulated return conductor is provided, then ground reference stability is improved, but device complexity increases
Solution Approach 1:
The battery assembly is equipped with a dedicated ground connection that establishes a fixed reference potential. By connecting the negative terminal to this ground reference through an electrically insulated return conductor, the system achieves equipotential conditions that prevent potential drift while maintaining clear separation between signal and power grounds.
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 configuration provides a cost-effective and efficient battery solution for electric vehicles, maintaining a stable ground reference and preventing potential drift, suitable for higher output applications like trucks and omnibuses.
Implementation Method 1
the connection between the connection point of the battery arrangement on the one hand and the ground potential on the other hand is preferably made via a capacitor that carries away these alternating components
Implementation Method 2
the electrical connection between the connection point of the battery assembly on the one hand and the ground potential (e.g., vehicle chassis) on the other hand can also be made via a high-resistance connection to dissipate such DC components
Data Source
Figure 1
AI summary
The invention relates to a battery arrangement (1), in particular for an electrically powered motor vehicle, comprising at least two batteries (2, 3) connected in series, a positive terminal (4) for connecting a forward conductor (6) to a consumer (9), a negative terminal (5) for connecting a return conductor (7) from the consumer (9), and an electrical connection point (10) between the batteries (2, 3), as well as a ground potential (GND), in particular in the form of a motor vehicle body, wherein the positive and negative terminals of the battery arrangement (1) are electrically isolated from the ground potential (GND). It is proposed that the connection point (10) between the two batteries (2, 3) be connected to the ground potential (GND) in order to maintain the potential between the negative and positive sides at a constant level.