EV Charging Levels Tuned for Regenerative Braking Headroom
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Solution Overview
Problem
Electric vehicle batteries often require frequent charging, and when fully charged, additional energy from regenerative braking must be dissipated, which can damage the battery and is inefficient, as it typically involves heating resistors that incur costs and energy waste.
Innovation Solution
A method for charging electric vehicle batteries at charging stations that stops the charging process below the fully charged level, predicting battery regeneration based on the vehicle's weight, route topography, and regeneration efficiency, allowing the battery to recharge during travel between stations, thus optimizing battery utilization and minimizing energy dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the battery is charged to the nominally fully charged level, then the charging capacity is maximized, but the regenerative energy during braking must be dissipated through resistors causing energy waste and potential battery damage
Solution Approach 1:
The charging process is stopped preliminarily before reaching the nominally fully charged level, anticipating the upcoming regenerative energy from downhill sections or braking. This preliminary stopping prevents the battery from being fully charged, creating capacity headroom to absorb regenerative energy without dissipation through resistors.
Solution Approach 2:
The system uses feedback from topography data, vehicle weight, and regeneration efficiency to dynamically determine the optimal charging stop point. By continuously monitoring these parameters and their impact on predicted regeneration, the system adjusts the charging level to maximize energy retention while preventing battery damage.
2Loss of energy
If regenerative braking is used to charge the battery, then energy efficiency is improved, but the battery may become overcharged and damaged when already at nominally full charge
Solution Approach 1:
The system performs preliminary assessment of the charging state before enabling regenerative braking. By calculating predicted regeneration based on route topography and vehicle parameters, the system determines in advance whether the battery has sufficient capacity to safely absorb regenerative energy, preventing overcharge conditions.
Solution Approach 2:
The battery management system autonomously monitors its own charge state and regulates regenerative braking acceptance. When the battery reaches the predetermined charging level, the system automatically stops accepting regenerative energy, allowing the vehicle to switch to conventional friction braking without manual intervention.
3Loss of energy
If the charging process is stopped below full charge level, then regenerative energy can be absorbed, but the charging time is extended and productivity is reduced
Solution Approach 1:
The system changes the charging parameter from fixed full-charge termination to dynamic level-based termination. By adjusting the charge level parameter based on predicted regeneration, topography, and vehicle weight, the system optimizes the balance between energy retention and charging time, stopping at the precise moment when the battery has sufficient headroom for upcoming regeneration.
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 approach optimizes battery charging by utilizing regenerative energy during travel, reducing the need for external energy dissipation methods and minimizing waste, while maintaining efficient battery operation.
Implementation Method 1
The electric vehicle may comprise a regenerative braking system configured to transfer the kinetic energy of the vehicle into stored energy by charging of the battery as the electric vehicle brakes or slows down.
Implementation Method 2
The wireless charging system typically includes a charging station having a power emitting coil, or transmission coil, configured to emit electromagnetic radiation.
Implementation Method 3
The wireless charging system typically further comprises a power receiving coil, preferably arranged on the electrical vehicle and in electrical communication with the battery, and being configured to receive the emitted electromagnetic radiation for charging the battery.
Data Source
AI summary
A method for charging an electric vehicle in a charging station system comprising a plurality of charging stations separated by predetermined routes with known topography is provided. The method comprises: performing a charging event of a battery of the electric vehicle using an external power source at a first charging station; stopping the charging event at a predetermined charging level below the nominally fully charged level, the predetermined charging level being set to correspond to the predicted battery regeneration when driving the electric vehicle along a predetermined route from the first charging station to a second charging station.