Vehicle Battery Switching Control for Derated SOC and Temperature Balance
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Solution Overview
Problem
Existing vehicle battery systems face challenges in efficiently managing state of charge (SOC) and temperature across battery strings, particularly in derated states, which can lead to reduced battery life and performance.
Innovation Solution
A battery system with a switch control module that adjusts upper and lower limits for charging and discharging, and controls switching to balance SOC and temperature across multiple battery modules based on the vehicle's derated state, state of health, and operational conditions, ensuring optimal power delivery and extending battery life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the battery system operates in derated state without adjusted charging/discharging limits, then the battery can deliver full power output, but the battery life is reduced due to excessive stress and temperature
Solution Approach 1:
The patent implements dynamic adjustment of charging and discharging limits based on the derated state of the vehicle. The switch control module continuously monitors vehicle operational status and modifies battery string configuration (series/parallel connections) in real-time, transitioning from static to dynamic operation to balance power delivery with battery longevity
Solution Approach 2:
The system changes operational parameters (charging/discharging limits, voltage thresholds, current limits) according to the derated state. When the vehicle is in a derated state, the controller adjusts these parameters to reduce stress on the battery, thereby extending battery life while still meeting power demands
2Power
If the battery strings are connected in series to maximize voltage output, then the power delivery capability is improved, but the temperature across battery strings becomes unbalanced leading to reduced reliability
Solution Approach 1:
The switch control module dynamically reconfigures battery strings between series and parallel connections based on real-time temperature monitoring. When temperature imbalance is detected, the system transitions to parallel connections to equalize temperature across strings, then alternates to series connections for voltage boosting, creating a dynamic balancing mechanism
Solution Approach 2:
The system implements periodic switching between series and parallel configurations to prevent sustained temperature imbalance. By alternating connection types at scheduled intervals or based on temperature thresholds, the system ensures that no single battery string remains in high-stress series configuration too long, maintaining reliability
3Device complexity
If the battery system uses fixed charging/discharging limits, then the control system is simple, but the battery performance is suboptimal in derated states
Solution Approach 1:
The switch control module serves multiple functions: it manages series/parallel switching, monitors temperature, adjusts charging/discharging limits, and responds to derated state conditions. This multi-functional approach consolidates control complexity into a single module while optimizing battery performance across various operational scenarios
Data Source
AI summary
A battery system for a vehicle includes: a first positive terminal, a second positive terminal, and a negative terminal; switches; at least two battery modules each including at least three strings of battery cells that are configured to, at different times be: connected in series and to the first positive terminal via first ones of the switches; connected in parallel and to the second positive terminal via second ones of the switches; and disconnected from both of the first and second positive terminals; and a switch control module configured to, based on a derated state of the vehicle, adjust at least one of an upper limit for charging of the battery strings and a lower limit for discharging of the battery strings.