Dynamic Battery Current Protection for Electric Vehicles
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Solution Overview
Problem
Existing battery management systems in electric vehicles face challenges in accurately limiting battery charge and discharge currents to prevent overcurrent or undercurrent, which can impact vehicle operability and safety, as traditional threshold limits do not consider dynamic operation conditions such as state of charge, temperature, and duration of operation.
Innovation Solution
A system and method for controlling the maximum current threshold of a battery system within a vehicle, utilizing a battery monitoring unit and a battery control system that monitors current parameters, determines event durations, and adjusts maximum current limits based on time thresholds, RMS-values, and operational conditions to ensure safe and efficient battery operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional fixed threshold limits are used for battery current protection, then battery safety is maintained, but vehicle operability and performance are degraded due to overly conservative current limiting
Solution Approach 1:
The patent implements dynamic current threshold adjustment based on real-time battery state parameters including state of charge (SOC), temperature, and duration of operation. The maximum current limit transitions from a fixed value to a dynamically adjusted value that adapts to current battery conditions, allowing higher currents when safe and lower currents when risk increases, thus resolving the contradiction between safety and performance
Solution Approach 2:
The system changes the parameter of maximum current limit from a constant value to a variable value based on multiple parameters including SOC ranges, temperature thresholds, and event duration. By monitoring these parameters and adjusting the current limit accordingly, the system achieves both safety (through parameter-based protection) and performance (through optimized current utilization)
2Reliability
If conservative current limits are imposed on batteries, then battery damage is prevented, but available current for vehicle operation is reduced
Solution Approach 1:
The system allows partial exceedance of traditional conservative limits by implementing time-based thresholds. Short-duration current events can exceed the maximum current limit if they occur within safe duration windows determined by the system, enabling the vehicle to utilize additional current capacity when needed while still protecting the battery from sustained overcurrent conditions
Solution Approach 2:
The available current is dynamically adjusted based on real-time battery state rather than being fixed at a conservative level. When battery conditions are favorable (appropriate SOC, temperature within range), the system permits higher current draw, thereby increasing available current while maintaining protection through continuous monitoring and dynamic threshold adjustment
3Device complexity
If simple fixed current thresholds are used, then control system complexity is minimized, but accuracy of current protection is insufficient for dynamic operating conditions
Solution Approach 1:
The system introduces multiple parameters (SOC, temperature, event duration) to determine the maximum current limit, transitioning from a simple single-threshold approach to a multi-parameter decision system. This increases protection accuracy by considering the actual battery state while maintaining manageable complexity through structured parameter evaluation and predefined threshold tables
Data Source
AI summary
Various systems and methods for controlling a maximum current threshold of a battery system within a vehicle are presented. The systems may include a battery module, one or more vehicle systems, a battery management system having a battery monitoring unit that monitors a current parameter, and a battery control system that receives the current parameter from the battery monitoring unit. The battery control system may be configured to identify a current event for the battery module, determine a duration of the current event, compare the duration of the current event to a plurality of time thresholds, determine the current parameter based on the duration of the current event, determine a maximum current parameter based on the duration of the current event and the current parameter, and control the one or more vehicle systems such that a current of the one or more batteries does not exceed the maximum current parameter.