Rail Vehicle Battery Circuit With Separate Charge-Discharge Paths
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Solution Overview
Problem
Lithium-ion battery units for rail vehicles are not suitable for auxiliary operations due to their electronic protective devices, which have limited availability and can preventively shut down, making them unreliable in emergency situations.
Innovation Solution
A battery arrangement with a circuit that separates the charging and discharging paths, using hardware protection elements with high availability to ensure safe operation even if the electronic protective device fails, and includes components like fuses, charging contactors, and undervoltage relays to prevent short-circuit, overcharging, and deep discharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If lithium-ion battery units with electronic protection devices are used, then weight is reduced and performance is improved, but reliability in emergency situations deteriorates due to preventive shutdowns
Solution Approach 1:
The patent segments the battery protection system into two independent parts: an electronic protection device for monitoring and diagnostics, and a separate hardware protection circuit for critical safety functions. This segmentation allows the hardware protection to operate independently of the electronic device's availability status, ensuring reliability in emergencies while maintaining the weight and performance benefits of lithium-ion batteries.
Solution Approach 2:
The hardware protection circuit acts as an intermediary between the battery unit and the external environment, providing a direct safety mechanism that does not depend on the electronic protection device. This intermediary layer ensures that critical protection functions (overcharge, deep discharge, short-circuit protection) are always available, even when the electronic protection device is shut down or malfunctioning.
2Loss of information
If electronic protection devices are used to monitor battery status, then diagnostic capability is improved, but availability deteriorates due to limited reliability of electronic components
Solution Approach 1:
The patent separates monitoring functions (performed by the electronic protection device) from critical protection functions (performed by the hardware protection circuit). This allows the system to maintain diagnostic capability through the electronic device while ensuring that safety-critical functions remain available through the redundant hardware circuit, which is less susceptible to software failures and electronic component issues.
Solution Approach 2:
The patent applies different quality characteristics to different parts of the protection system: the electronic protection device provides intelligent monitoring and diagnostics with full information processing, while the hardware protection circuit provides simple, reliable, always-available protection for critical parameters. Each part is optimized for its specific function, ensuring both diagnostic capability and high availability.
3Reliability
If hardware protection elements are added to ensure availability, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent extracts the critical protection functions from the complex electronic protection device and implements them through simple, dedicated hardware protection circuits. This extraction reduces the complexity burden on the electronic system while ensuring that essential protection functions are always available through straightforward hardware mechanisms like fuses and voltage threshold circuits.
Solution Approach 2:
The hardware protection circuit uses simple, fail-safe components (such as fuses and basic voltage protection elements) that are inherently reliable and do not require complex control logic. These components are designed to be simple and robust rather than sophisticated, accepting slightly higher component count in exchange for dramatically improved availability and reduced electronic complexity.
Data Source
Figure 1
AI summary
The invention relates to a battery arrangement (BA) for the auxiliary operation of a rail vehicle, comprising at least one battery unit (BU) and a circuit for charging and discharging the battery unit, wherein the battery unit has an electronic protection device (BMU). According to the invention, the circuit has, for the positive input of the battery unit, a charging path (L) for charging the battery unit (BU) and a discharging path (E), different from the charging path (L), for discharging the battery unit (BU), wherein the discharging path (E) connects the positive input of the battery unit (BU) to the positive output of the battery arrangement (BA) as the discharging path, the charging path (L) being equipped with one or more electrical components, which provide protection for the battery unit (BU) against short-circuit current, overcharging and overheating, and the discharging path (E) being equipped with one or more electrical components, which provide protection for the battery unit against short-circuit current and deep discharge.