Amid the giddy rush to adopt Tesla’s NACS charging system, a few voices in the wilderness can be heard crying, “But what about bidirectional charging?”
Many see bidirectional charging, which enables V2G and related technologies, as a necessary part of the future EV ecosystem (California may soon mandate the capability for all new EVs). Vehicle-to-home, which allows EV owners to use their cars as a source of backup power, appears to be highly popular with prospective buyers, and vehicle-to-grid could turn EVs into a valuable resource for utilities, and a source of revenue for fleet operators (and better yet, it could silence the anti-EV trolls’ claims that EVs with “crash the grid”).
However, Tesla’s system doesn’t currently support bidirectional charging, and the company has never shown much interest in the technology.
New York-based Revel, which leverages the synergy between rideshare EVs and public fast charging hubs, operates what it calls “the first vehicle-to-grid program on NYC’s grid.” (See the feature article in our January-March 2023 issue.)
The company recently issued a statement calling for automakers—whatever charging system they adopt—to add V2G capabilities to their EVs.
“All of Revel’s public fast charging sites have always and will continue to offer both CCS and NACS connections,” says Revel. “We support plug standardization because it will open up the full market of EV infrastructure—which today is sparse especially in dense urban areas—to more consumers, helping ease the transition to electric.
“As EV adoption grows, however, we’ll need to ensure our sector supports grid reliability and resiliency. Vehicle-to-grid technology makes EVs an asset to the grid, not a liability. We urge the EV industry to fast-track V2G research and development for both CCS and NACS fast charging, and for automakers to enable V2G capabilities on all future electric vehicle models.”
Schaltbau, a supplier of safety components for DC systems, has designed contactors to meet the charging and driving requirements of 800-volt EVs, which are equipped with two 400-volt battery banks.
The C801 interlock contactor is compact and designed to fit the usual installation geometries inside an EV. The contact area has substantial air gaps, allowing for an insulation voltage of 1,000 V. Due to strong contact forces and optimized contact geometry, the contactor can withstand a thermal continuous current of 250 A and a short-time withstand current of 16,000 A during operation.
The contactors only operate while charging at 400 V charging stations and do not consume power or generate heat when driving or charging at 800 V. The contactor includes a proprietary mechanical interlock system that keeps the connections from closing even if there are extreme shocks of up to 120 g per 20 ms. Schaltbau is also preparing to produce interlock contactors to meet increasing demand for high-range mid-size vehicles as well as commercial vehicles and buses.
“When driving, the contacts are open,” explains Günther Rott, Director Business Development Automotive of Schaltbau. “Therefore, it is important that the contactor does not close uncontrollably even under high mechanical loads, as may occur during an accident. Were this to happen, the consequence would be a short circuit that would destroy the junction box and probably also the vehicle.”
The increase in demand for EV Batteries has already permanently transformed the car manufacturing landscape, with almost all major automotive companies now operating electric vehicle production lines.
While electric vehicles do have less moving parts than their internal combustion engine (ICE) counterparts, manufacturing them is still extremely complex. From stators and rotors, to intricate wiring harnesses, LMI is involved with many EV manufacturing applications. But the heart of an EV is its battery, and this is where machine vision solutions have become essential to market success.
EV Battery Manufacturing Overview EV battery manufacturing can be broken up into 5 general steps: (1) electrode manufacturing, (2) cell assembly and packaging, (3) cell-to-module assembly, (4) module-to-pack assembly, and (5) final installation inspection.
Gocator 3D smart sensors and their built in, onboard measurement tools are used in every stage of this manufacturing process.
Let’s look at these applications individually.
Electrode Manufacturing Electrode slurry is coated onto copper and aluminum foil to facilitate electric flow. The metal surface, separator, and coating must be inspected for edge defects as well as uniform shape and thickness.
During this step, Gocator sensors are used to ensure uniform shape and thickness of the electrode as the slurry is applied. Sensors are also used to measure the distance between tabs on a cell sheet. Tolerances are extremely small for these applications so high resolution and small field of view sensors are used.
Smart 3D sensors are used for different tasks at this phase of inspection including:
Electrode Width Gauging – Accurate width gauging of the dimensions of the separator and electrode.
Electrode Edge Profile Measurement – High-speed profiling of the edges of coated electrode sheets to ensure the correct dimensional tolerances are met.
Tab Distance Gauging – Scanning and measurement of the distance between tabs on a cell sheet to meet dimensional tolerances.
Cell Assembly and Packaging A separator and electrode are joined together, and the joined cell (including anode and cathode) is either wound, rolled, or stacked. Stacked cells are then housed in a metal casing and sealed by welding.
Two of the most common cell types used in electric vehicles are cylindrical and prismatic. Cylindrical cells are packed together into groups and scanned for presence/absence, correct position and dimensions, as as well as for potential surface defects such as any dents or scratches on the cell top. Only 3D provides the shape (height) data required to inspect battery surface features and dimensions for defects such as bulges, fissures, warps, and more.
Prior to welding, a Gocator® or multisensor network delivers high-speed 3D laser profiling and a built-in tool to measure the gap & flush between the prismatic battery cell and its metal casing. After welding, they are inspected again to ensure that the weld seam is uniform and within tolerances.
The surface of the battery cell needs to be inspected for correct dimensions and to detect defects of the face, edges, and corners. It is also worth noting that smart 3D sensors like Gocator come with blue laser model options. The shorter-wavelength blue light generates higher-quality scan data (i.e., less noisy) on highly specular battery surfaces such as polished metal.
Cell-to-Module Assembly Once the individual battery cells are inspected for quality control, a set number of them are precisely grouped together to form a battery module. An example application for module inspection is for sensors to measure and inspect the weld seams of each module.
Gocator 2500 series laser profiler scanning prismatic EV battery module
Module-to-Pack Assembly Modules are then combined to form battery packs. Gocator sensors are used at the final stage of the process, combining modules into a single battery pack, ready to be installed into a new electric vehicle. It is necessary to measure and inspect its length, width, height, and flatness of each surface to ensure that all dimensions are matching the GD&T design tolerances.
Final Installation Inspection In electric vehicles, a large tray/pan sits underneath the floor panel. The lithium-ion battery pack is glued to this tray. Gocator sensors are used at this final stage to inspect the glue bead application for correct dimensions (height, volume, width, length) and surface quality (breaks, gaps, overflow etc.).
Choosing the Right 3D Sensor for Your EV Battery Application LMI Technologies offers a range of laser profile sensors that can handle any EV battery inspection application. For example, the Gocator 2500 Series offers ultra high-speed blue laser profiling for high-performance inspection of shiny EV battery surfaces. Or when even greater measurement precision is required, engineers can deploy the Gocator 2600 Series in their production lines for powerful ultra high-resolution 4K+ profiling.
Combine Smart 3D Scanning with AI-Based Inspection In addition to its suite of high-speed, high-resolution 3D smart sensors for EV battery scanning (with web browser interface and onboard software), LMI Technologies also provides inspection engineers with the option to add powerful FactorySmart AI-based inspection to their EV Battery production lines for the most complete end-to-end solution on the market today.
For example, in EV battery array inspection, engineers can deploy a set of tightly integrated LMI products from sensor hardware to edge devices and human-machine interface (HMI) in order to solve the application with maximum performance and cost-efficiency.
An example of this solution might include:
2x Gocator 2600 laser profilers for 4K+ high-resolution 3D point cloud generation of the EV battery array
2x GoMax NX edge devices for sensor acceleration and powerful AI-based surface defect detection
GoFactory interface for data management (performance monitoring, telemetry dashboarding, configurable alerts)
Conclusion EV battery production continues to grow rapidly around the world. LMI is not only supporting the current industry, but actively developing next generation sensors specifically designed to meet future battery production needs.
A new electric SUV has officially started rolling out. Kia has begun delivering its flagship EV9 electric SUV as it looks to continue expanding its brand in the era of electrification.
Schaltbau, a DC technology safety component and system provider, will deliver its new C801 high-voltage contactor for a German manufacturer’s EV platform.
Production is set to start at the end of 2024 in Schaltbau’s NExT Factory in Velden, Bavaria. The series production order has a duration of several years and a volume in the tens of millions. The 800 V EV platform uses the C801 as an interlocking contactor in the battery box (battery disconnect unit or junction box). A patented mechanical interlock system prevents the battery units from short-circuiting even in the event of shocks of up to 120 g per 20 ms.
“The flexible, automated production plant and the modular design of many Schaltbau components mean rapid scaling up of production is possible, and that parts can be made quickly available, even for custom requirements,” Schaltbau said.
The benefits of new technology generally flow downward from the top of the income ladder, and lower-income communities tend to be the most affected by pollution and environmental damage. However, in one California town, low-income residents are breathing a little cleaner air and enjoying the benefits of e-mobility, thanks to a local community group called the Green Raiteros.
The Spanish term raitero refers to the practice of neighbors providing rides to community members in need. The Green Raiteros, an EV ride-sharing initiative in Huron, California, shuttles low-income residents, many of them elderly, to medical appointments for free.
The Green Raiteros’ fleet currently consists of five Chevy Bolts, three Tesla Model Ys, two Volkswagen e-Golfs and a BMW i3. The organization has about 120 regular clients.
Huron is a small agricultural city in the Central Valley. Of the 6,200 residents, 95 percent are Latin and about 50 percent are immigrants. Neither Uber nor Lyft operates in the area, and public transport options are sparse.
Rey León, Huron’s mayor, launched Green Raiteros in 2018. When Mr. León was a child, his uncle worked as a raitero, shuttling the family and neighbors around in a green Pinto. He told the New York Times that Huron’s average household income is $35,000, and many residents spend 30 to 40 percent of their monthly wages on gas-powered cars that frequently break down. The region’s air is consistently ranked as some of the worst in the US. Tax credits and consumer rebates for EV purchases are useless to people who don’t earn enough to pay income tax, and who can barely afford a cheap jalopy. “Owning a car is a poverty perpetuator,” Mr. León told the Times.
Green Raiteros was founded with funding from private foundations and a settlement between utility NRG Energy and the California Public Utilities Commission. A $1-million grant from the California Air Resources Board paid for the Teslas, and the organization’s $150,000 annual operating budget is a mix of funding from CARB, other state agencies and philanthropies, as well as a recent contribution from GM. A Bipartisan Infrastructure Law grant paid for 30 charging stations placed strategically around the town.
Other inventive models for EV ride-sharing are popping up around the country. Several organizations offer rides to low-income residents in various California towns. In Minneapolis and Saint Paul, Minnesota, Evie Carshare, funded by city government, federal grants and local utility Xcel Energy, operates a fleet of 170 electric vehicles and 70 chargers in a low-income area.
Of the 270 people impacted by the decision, 150 were supporting Nikola’s European operations and 120 were based at its Arizona sites.
Source: Electric Vehicle News
