Electric Vehicles and Plug-in Electric Vehicles use an energy storage unit which is pre-charged and can power the electric motor to run the vehicle. The energy storage unit in the current market is predominantly an assimilation of rechargeable batteries into a battery pack. In the electric vehicle market, the major hurdle is the difficulty to match the performance of the energy storage units in terms of capacity and re-charging ease to a gasoline engine vehicle. The batteries packs of 53kWh capacity typically take 6-8 hrs of charge and run a midsize car for approximately 200 miles. In this scenario, battery replacement (exchange the discharged one with charged one) if done quick and easy can be a big time saver instead of waiting for hours to charge the vehicle every 200 miles. This battery replacement system needs to be able to handle battery packs of different size and shape and has to be completely automated. Building and infrastructure with these automated systems provides us with a viable solution for the electric vehicles.
The size of the battery pack and their arrangement decides the amount of total power and the voltage they can deliver to run a vehicle. These battery pack can vary in size based on the required capacity and can become very heavy. Handling of these battery packs, moving them around, accessing the vehicle to replace them are all part of the design challenges for the operation of a successful battery replacement unit.
This invention is a complete end to end solution from when the vehicle enters the Battery Replacement Unit with a used (discharged completely or partially) battery pack and leaves with a charged battery pack based on the requirement of the driver. The communication with the driver is established at the user interface and business transaction is implemented. Along with the design aspects of the system, the invention gives a detailed operational sequence for the battery replacement unit.
This invention provides a complete solution to build and operate a battery replacement unit, which can service multiple vehicles at the same time just like in a gas station. This invention also provides a modular solution to handle different vehicles with different battery packs. The system is completely automated with equipment to move the heavy battery packs from the vehicle into the storage station and from the storage station into the vehicle. Further, a separate system automates the interaction with the vehicle during the exchange of the battery pack.
The BRU also has a system to recharge and service the battery packs exchanged from a vehicle. A part of the energy used to charge the batteries is obtained by the solar panels installed on the BRU’s real estate. The rest is supplied by the utility company.
The system is designed to automate the process of changing the battery in a vehicle with minimal user (vehicle user) effort.
The following are the key components of the fully automated Battery Replacement Unit.
- Battery Cart
- Designed specific to the battery pack
- Automated Clamps to hold the battery packs
- Transported on standardized pathway for all Battery Carts
- Equipped with the Safety and Positioning systems
- Battery Storage Area
- Recharge batteries
- Monitor and Store Batteries
- Service and Maintenance of Battery Packs
- Safety Systems
- Battery handling (transportation) system
- Move the batteries for replacement in the vehicle
- Move the battery from the vehicle to storage or a charging point.
- Move, assign and store battery from the supplier for the inventory maintenance
- Battery exchange
- Vehicle guidance and positioning
- User Communication
- Vehicle access system
- Battery positioning system
- Battery ejection
- Battery securing
- Testing of the operation
- Software Controls and Communication
- User Communication
- Business Transaction (Credit/Debit Transaction)
- Control Systems for Equipment Automation
- Battery Pack Data Handling System
Once the vehicle drives to the station for a service, the automatic positioning system positions the vehicle accurately for the Battery Pack exchange. The Battery Packs are stored and serviced (charging/repairs/maintenance) in the storage station while they wait for the exchange from EV. The storage station can be built above the ground or below the ground in areas where space is a restriction.
After the communication with the vehicle and the user, the system software identifies a Battery Pack from the storehouse and moves it through automated materials transport stations. The battery pack finally reaches the operation bed where it is aligned with the vehicle for the exchange. While the identified Battery Pack is transported, the operation on the EV would extract the existing discharged Battery Pack from the vehicle and prepare it to transport system takes the battery unit to the assigned position in the storage station. The servicing of the unit is done at the storage position or it could be serviced before being secured at the storage position.
At the operation bed, the unit is replaced and the doors locked for some final testing. Once a clean operation is ensured, the vehicle is released and the gate is opened for the customer to drive off.
The system is designed to handle different unit types (recognized Battery packs). The installation/exchange system is also designed to handle the battery packs which are accessible from above or underneath the vehicle.
In a specific design, an electric vehicle can be equipped with energy storage unit which can be split into multiple packs. Each pack could be connected in particular configuration (circuit) based on the requirement of the user to have better performance on miles or on speed/torque. The BRU identifies such electric vehicles with flexible battery arrangement and specifies the options to the user. Its automatic material handling system inserts the battery packs in the specific slots based on the user choice.
The operation of the end to end automated Battery Replacement Unit can broadly be divided into following four steps.
- Battery Pack transportation
The main component being handling in this automated material handling system is the battery pack. They come in few different shapes and sizes. Once they arrive at the station, they are moved and prepared for storage. The first step is to place them in specific cart (Figure 1). The cart is equipped with castor wheel for ease of motion on an interconnected rail. The battery unit is tested and registered in the system database before being positioned on the storage rack.
- Truck-to Rack
The battery unit is transported in cases or racks designed for safe handling from the vendors by a truck or similar vehicle. The truck is pulled to a door of the storage station (Figure 2), where it is semi-manually unloaded and the battery units are placed on the respective carts. The preliminary tests are procedures are performed to ensure the quality, and then the units are registered in the database system. The carts from the truck transport the units straight to the storage racks, where the vertical automatic stage hauls them into position in the rack and locks them for charging.
- Unit dismantling from truck
- Unit positioning on cart
- Unit testing and registering into the database
- Allocation of storage spot
- Transport to storage rack
- From on-ground transport to the position on the rack using the vertical lift.
- Storage Rack to On-ground transportation system
The identified unit is transported to the on-ground rail line by a stage dedicated to the specific battery unit type (Figure 3). The optimum path is calculated by the system and the motion actuators carry out the functionality to orient the battery unit accordingly.
- System identifies the unit and alerts the actuator system of the specific unit.
- The Z-lift positions itself in-front of the unit for transfer.
- The locking system releases the unit-cart.
- The actuation system on the z-lift pulls the cart on to the platform
- The locking system on the z-lift secures the cart
- The stage moves down in place for the on-ground transportation to take over.
- On-ground transport and Ground to exchange stage transfer
The on-ground transportation contains the conveyor or chain based motion system to carry the cart to the designated operation bed lift. Sensors are used to keep monitor the operation.
- On-ground transportation is activated once the cart is locked in place for transportation.
- On-ground transportation moves the cart to the exchange station lift.
- Cart is unlocked from the on-ground transportation after the exchange station lift is reached
- Lift pulls (or the cart tilts to slide on) the cart on to the platform.
- Cart is secured on the platform
- Cart is raised and positioned to the 4-dimensional (4-D) precision positioning stage
- Battery is dismounted from the cart and rolled on to the 4-D stage
- Battery pack is secured
- Battery orientation and position are matched with the pocket (opening) in the vehicle.
- Vehicle Guidance
The operation begins with the user driving into a Battery Replacement Unit (like a gas station) and positioning the vehicle close to the automatic vehicle positioning system. The position here is guarded by an automatic gate. The customer interacts with the system to communicate the vehicle identification and other requirements. Based on his choice of service, cost and the estimated time are presented to the customer.
The gate opens for the customer to move the vehicle to the entrance of the auto positioning system (Figure 4 & 5). Vehicle is stopped and put it in neutral gear. From here the auto-positioning takes over and moves the vehicle in place for the operation to begin.
- Vehicle pulls into the station
- Verification and registration is done at the gate
- System identifies the battery unit from storage and directs the storage material handling system to move the battery towards the op bed.
- Gate opens after the user selects one of the options presented by the system
- User drives the vehicle into the guided conveyor. Correlator helps to align the vehicle with the guides.
- At the stop line, vehicle engine is stopped and put in neutral
- Conveyor system positions the vehicle for the operation
- System interacts with the vehicle to open the door from underneath of the vehicle to access the battery pack
- Test are done to ensure the good battery connections
- Gate opens for the vehicle to drive off of the guided conveyor.
- User drives out
- Gates closes and prepares the exchange station for the next vehicle
- Battery Pack Exchange
This motion automation system has two separate modules. The movement of the Battery pack from the vehicle and movement of the battery pack into the vehicle.
The door handling module accesses the door of the vehicle from underneath the vehicle to open it. It secures the door until the battery pack exchange is done. The same system also unlocks (or activates the automatic locking) the battery unit inside the vehicle. Further the system will close the door and secure it to the vehicle once the operation is over. Safety tests are done to ensure proper engagement and securing of the battery pack during the operation.
Operation Steps – Battery Pack from Vehicle
- After the vehicle guidance system secures the vehicle at a desired position, the user is prompted to authorize the system to start the battery replacement procedure.
- After verifying the safety measures, the system moves the door ajar to have access to the battery pack (Figure 6). The door is secured with pneumatic or mechanical locks.
- After the 4-D stage positions itself under the battery the system unlocks the battery locking system.
This module positions the battery and lifts the battery unit in place to make the connections (Figure 7). This module also supports the battery unit when taking it out of the vehicle and transfers it to the vertical lift.
Operation Steps – Battery into the Vehicle
- Battery unit after being transferred to the 4-D stage, is supported from underneath. After positioning the battery using the sensor (photographic/simple 3-d readers) system, the 4-D stage pushes it into the pocket in the vehicle
- Connections are established and verified
- Battery pack is secured in the vehicle
- Battery Pack Servicing and Charging
The charging of the battery is done on the storage rack. Each rack position is equipped with a charging system which docks on to the battery pack when it is in place. The automation system manages the voltage and current characteristics of the charging system based on the requirements and the battery condition. This charging system is undocked only when the battery is ready to be moved out of the rack.
Operation Steps – Docking
- Battery cart is positioned on the rack and secured.
- Charging system is engaged by the actuation system mounted on the vertical stage.
- Connection is tested and verified
- Automation system senses the battery on the charging station or storage rack and charges the battery based on the configuration and requirement
Operation Steps – Un-Docking
- After the vertical lift positions with the battery on the storage rack, the automation system registers switches off the connection to the battery and the change in status recorded.
- The system (on the stage) undocks the charging system from the battery pack.