There were some interesting developments at the recent and aptly named Battery Show near Detroit for those who follow battery technology. One in particular came from the Michigan-based Our Next Energy (ONE). The firm released details about a 240-Ah prismatic cell battery it has designed and which is said to be the highest energy density large-format cell yet produced. Perhaps the most noteworthy fact about the new battery is that its design eliminates the need for graphite and anode manufacturing equipment—ONE dubs it anode free, though it is indeed polarized. That lets ONE cells be produced using about half the current manufacturing equipment needed to make equivalent capacity cells today.

ONE figures it will be able to turn out the new batteries at a cost of $50/kWh. For comparison, the average new EV battery goes for around $128/kWh, a price likely to rise because of inflation and the scarcity of rare earth minerals.

But if you buy an EV and its battery dies after the warranty expires, you’re probably going to end up paying a lot more than $128/kWh. Greencars, a website specializing in EV learning and shopping, reported in 2020 that 16 kWh Chevy Volt battery packs cost about $4,000 to replace, putting them at about $240/kWh. Keep in mind that a brand new Volt costs about $26,600 when it comes off the showroom floor. A 2011-2015 Chevy Volt remanufactured battery pack is priced at $6,000 at Greentec Auto, a company specializing in hybrid battery replacement. These batteries have 17.1 kWh of capacity, putting their price at $350/kWh in 2021 dollars.

Most EV owners can be thankful that car makers typically warranty the battery in these vehicles for between eight and ten years and 100,000 miles. But it’s clear that out-of-warranty battery problems on EVs or hybrids can get expensive. Recurrent, an organization that covers pre-owned EV transactions, points out that the cost of an out-of-warranty 100 kWh battery (as found on long-range Tesla vehicles) replaced in 2025 might range from $5,600 to $13,500, depending on whose predictions you want to believe.

These estimates assume that industry continues making advances in battery technology similar to that just announced by ONE. Today battery replacements even in budget-priced vehicles are pricey. The Nissan Leaf, which starts at about $27,800, can come with batteries ranging in size from 30 to 62 kWh. Replacement costs for these batteries range from about $3,500 to $9,500. Even hybrid EVs with their relatively smaller batteries have eye-popping battery replacement costs. Consider the 2022 Hyundai Ioniq Plug-In Hybrid which starts at $26,800. A replacement battery for a 2018 or 2019 model had an MSRP of $2,853.53 last year. The battery in the Ioniq HEV is 1.56 kWh, equating to about $1,829/kWh.

New-car warranties mean that buyers of new EVs probably don’t worry much about replacing their batteries. But EV battery cost is a top-of-mind for those of us who typically buy used cars. I myself am in this group. It was more than 30 years ago that I bought my last new car off a dealer lot. I don’t see myself buying a used EV knowing I may have to shell out 15% of what I paid for the car in a year or two when the battery gives out.

I suspect I am not the only potential used-EV buyer who thinks this way. Baring drastic improvements in EV battery pricing, the automotive industry may be faced with a new paradigm as EVs age: It may end up being impossible to sell a used EV without first replacing the battery. Alternatively, buyers like me will be unwilling to buy used EVs without a drastic price drop that far exceeds typical Blue Book depreciation for ordinary ICE vehicles today.

Whatever happens, it will be interesting to watch.

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Even electric vehicles get hot rodded

Legacy EV specializes in aftermarket EV applications, offering products like integrated EV systems, certified EV technician training programs, and EV design consultation for businesses. It is one of the places you can go if you want to put, say, a Tesla electric drive in a conventional ICE chassis. This hot rod at the Legacy booth is an example of what’s possible with a Legacy EV conversion kit. Besides electric drives from Tesla, Legacy also handles units made by Cascadia Motion, NetGain, UQM/Danfoss, and Revolt Systems. Other notable builds employing Legacy kits include a 1971 Electric Chevy C-10 built by Old Town Auto featuring 253 hp and 356 ft lbs of torque, a 1965 Electric Volkswagen Bug equipped with 127 hp, 173 ft lbs of torque, and 91 miles of range; and a 1966 electric Caddy is powered by three Netgain Hyper 9 Motors and a custom lithium-ion battery pack.

When the fan is fed by an orange wire

Orange wires in electric vehicles mean high voltage. And the orange wires on these fans from EMP (Escanaba, Mich.) mean the fans can work directly from the 850-V powertrain bus voltage. EMP says these Smart Flow FiC-15 e-fans are currently being integrated into several FCEV and BEV cooling applications. They’re designed for use in medium and heavy-duty on-highway vehicles and electric industrial vehicles. These fans can run at 500 – 850 V with up to 3 kW of power. The HV fans are CAN controlled for variable speed and include diagnostic capabilities.

Heavy duty trucks go electric

This is what a Navistar International truck looks like these days. More specifically, this is an eMV Series which is a little over 30 ft long and carries a 255 kW electric motor developing 2,355 Nm of torque at 1,000 rpm. The truck is based on the diesel MV but with air tanks and air-bag management, as well as a 210 kWh battery pack regen braking, and a fast-charge capability of up to 125 kWh. The electric truck is also said to have a 135-mile range.

Big wheels keep on turning

What you see here is a truck wheel, held up by Simon Pinter of Computer Aided Technology (Buffalo Grove, Ill.), that has been 3D printed out of ABS in two parts and then welded together. The firm used a Stratasys F900 large-volume printer to do the wheel which is a form-and-fit type model. Computer Aided Technology provides equipment and expertise for product development efforts.

Development cycle for a motorcycle

Dewesoft is a provider of data acquisition equipment. So the company put some of it to work on an electrified motorbike and a trailer carrying a cooler. It instrumented the bike with sensors for factors such as battery current and temperature, wheel speed, temperature inside the towed cooler, and a few other things. The detailed readouts are visible in the screen shot below. The view from the driver’s seat can be discerned from the short video we shot of the demonstration.

Formula E at the battery show

There was one Formula E car at the Battery Show. Fielded by Jaguar and appearing at the Dow booth, it features a maximum power limited by Formula E specs to 250 kW, equivalent to 335 hp and 22-in Michelin Pilot Super Sport tires, among other things. It’s 0 – 60 mph speed is 2.8 sec and has a max speed of 174 mph. The Generation 2 lithium-ion battery (848 lbs, 52 kW) sits in a carbon fiber safety cell and has the usable energy of 5,000 fully charged mobile phones, Jaguar says. The silicon-carbide module I-TYPE inverter is from Jaguar Racing. Visible in the image is the new FIA Halo head protection device, with its LED light strip. When the lighting on the Halo glows blue, the car and driver are in Attack Mode. The Halo glows magenta when the driver has activated FanBoost, allowing fans to follow their strategy.

Excavators go electric

Not many makers of electric powertrain equipment for the off-road industry can claim to have a signature cocktail, but that is the case for Turntide Technologies, Sunnyvale, Calif. The firm celebrated its 300,000th vehicle milestone by serving its cocktail at its Battery Show booth. (For the curious, the cocktail consists of 1 oz vodka, 0.5 oz triple sec, 0.5 Blue Curacao, ice, and a lemon twist.) On display at the Turntide booth was its Gen4 Size 2 ac induction motor controller (top left), an eCP80 high flow 24-V electric water pump with variable-speed control via an integrated motor controller (top right), a Gen5 Size 9 high-voltage (128 to 450 V output) motor controller (below right), and a couple Hyperdrive batteries, which are basically lithium-ion battery packs combined with a BMS. The battery at right is a standard 4.94 kWh/111 Ah device.

Ode to silicon anodes

As you might expect, there were several new battery technologies highlighted during the conference and show. In one conference session, Enovix discussed its silicon anode technology. Batteries carrying silicon anodes have a reputation for swelling during the charging process, a drawback Enovix claims to have solved by reorienting the electrode stack and using a pre-lithiation process. On the show floor, Our Next Energy (ONE) in Novi, Mich. debuted a “anodeless” battery cell with an energy density of 1,007 Wh/l. Despite the anodeless moniker, the cell retains a positive and a negative pole. But its anode (metal) doesn’t use graphite, thus eliminating the need to use classic production equipment to process this material. This is said to significantly reduce manufacturing costs to below $50/kWh.

The post Gallery: Sights and sounds at the Battery Show North America 2022 appeared first on Power Electronic Tips.

Everything is solid-state these days, right? Even that one holdover, the vacuum-tube magnetron at the heart of the home microwave oven, is seeing some early signs of competition from cost-effective solid-state power amplifiers. Vacuum-tube amplifiers are used in only some specialty equipment such as high-power transmitters (we’re not looking here at audio enthusiasts who feel tube-amplifier sound technology is better than solid-state; that’s a personal decision).

It’s the same with the solid-state relay (SSR) versus the old electromechanical relay (EMR): the former is now the first relay of choice in most situations and for many legitimate reasons. The function of a relay is conceptually simple: to allow one on/off signal to control the on/off state of another signal line without any electrical contact between them. When you need a relay function, it’s normal to first think of the modern, solid-state version of the classic electromagnetic relay.

The EMR, which is the oldest “electrical” component (thank you, Michael Faraday), functions by energizing a primary-side coil that pulls in an armature, which then causes contacts to close (or open, depending on design) (Figure 1 ). But wait a moment: there are many design situations where the older EMR is still the better or more flexible choice. EMRs fall into three categories: small signal, power, and RF. While their input and output levels, voltages, currents, and frequencies differ, they all have to same operating principle.

In contrast, the SSR input has a photoemitter on the input side and a photodetector on the output side and operates on electro-optic principles rather than electromagnetic ones. Consequently, the input voltage/current is fairly constrained, while the output has some limitations as well.

Despite the many well-known, proven, and impressive virtues of SSRs (no need to repeat them here) and countless tens of millions (maybe billions?) being used in new designs every year, tens of millions of EMRs are also sold each year. While some are for replacement requirements, a significant fraction of these are for totally new design-ins.

What are the attributes of EMRs that keep them going strong? While the EMR is functionally similar to the SSR in the broadest sense, it has many unique characteristics and virtues. Both offer galvanic isolation, but the EMR can do many things which an SSR cannot. Some of the unique attributes and advantages  of the EMR include:

1. The relay contact forms a basic switch closure, and current through it can be AC or DC, independent of the coil drive; the contact resistance is in the milliohm range, so the voltage drop across the contacts is very close to zero; the open-contact resistance is an air gap and therefore in the multi-megaohm range with near-zero leakage current.
2. The EMR is an entirely passive device without active components such as an LED or phototransistor. This has implications for ruggedness and reliability. It is electrically and mechanically robust (partially due to its mechanical and thermal mass) and resists spikes, transients, and EMI, which might momentarily trip or even damage an SSR. Most EMRs are rated for millions of operating cycles, while the sealed reed relay (a type of EMR) has a rating in the tens of millions.
3. Despite the metal frame of most relays, neither coil nor contact closure are grounded or connected to circuit common, so the relay can be placed anywhere in a circuit; that can be difficult due to the active nature of the SSR with some circuit topologies.
4. While basic relay contacts are normally open (NO) when not energized, there are standard relays with normally closed contacts (NC) when not energized – and many ones that have both, using combined NO/NC contact pairing.
5. The relay can be a multipole, multi-contact device with more than one NO or NC contact pair; three, four, or even more independent NO and NC contacts are available, with double-pole/double-throw (DPDT) being the most common (Figure 2).

   

6. Even more flexible, these multiple contacts do not have to be carrying the same type and rating of loads, which is another benefit; some contacts can be rated for low-level signals while others can be for power. Where there are a few – just a few – multiple-pole SSRs on the market, they are very limited in scope and ratings.
7. Relays can be designed for coil currents as low as 10 or 20 mA or as high as tens of amps, with contacts rated to handling just a few tens of mA and a few volts all the way to several orders of magnitude greater for both parameters.
8. EMR contacts are signal “agnostic;” as long as you stay within the voltage and maximum current ratings, it is irrelevant whether it’s a power signal, data signal, or mix across multiple contacts. Further, the load does not have to be well known or defined; it just has to be within the design limits; this is useful in cases where the load may have unknown, uncertain, or hard to control characteristics.
9. The most common failure mode of an EMR, by far, is the coil not becoming energized, so a NO contact fails “open” while an NC contact fails “closed” – which one is preferred or necessary may be a safety issue in the application. In contrast, SSRs tend to fail with a short circuit at their output, which may not be acceptable.
10. There are standard EMRs available called “latching” relays that maintain their energized contact position even if coil power is removed or fails (a separate coil and signal unlatches them); this is a nice feature in some situations and a vital one in some safety-related ones.
11. The relay is very easy to troubleshoot; all that is needed is an ohmmeter to measure the unpowered coil continuity and DC resistance and a simple AC or DC power source to energize the coil.
12. Finally, and this is a personal factor for some designers, there’s the viscerally satisfying “click” and observable movement of the armature, which the EMR makes when the relay pulls in or drops out. Some engineers love to hear the “click-click-click”, and even use it to monitor system activity.

Of course, the above reasons do not mean the EMR is “better” than the SSR: they each have their strengths and weaknesses, and SSRs are the better and often only viable choice in many cases.

Personal evidence is just one example

I have many personal situations as a testimony to the usefulness of EMRs. For example, many years ago, I needed to replace a defunct landline phone dialer on a home alarm system. I assumed that the previous dialer and this new one from the same company would be electrically consistent and compatible.

That was not the case. The previous dialer required a transition from high to low to trigger it, while the new one was seeking a transition from ground to “open circuit” as its trigger. Unfortunately, “open circuit” is one of those sometimes-ambiguous circuit terms: does that mean “floating” (truly open), or would disconnecting the line via an open-collector output be sufficient?

Adding to the challenge, the alarm-control unit’s documentation about its output pin was amazingly unclear as to its electrical nature: it might be an open-collector structure, or maybe not. Thus, I could not even say for sure if the control unit’s output was at least potentially electrically compatible with the dialer’s input needs.

What to do? I thought about it for a while and summarized the problem: what I had was an output that went from high to low with unclear structure, and what I wanted instead was for it to look like a dc-signal going from ground to open.

Then, the solution became obvious: use a basic electromechanical relay. I found a DPDT unit with a 12-V, 10-mA coil in my collection. I connected the coil between the supply rail and active output of the control unit and used the relay contacts to connect the input of the dialer to true ground. When the control unit’s output went low (pulled down), it energized the coil, which opened the normally closed relay contacts, and thus provided a true open circuit to the dialer input.

Problem solved…the relay functioned as both a level shifter and signal inverter and gave me absolute electrical (galvanic) isolation as well, so any signal issues at the output of the alarm unit would not damage the input of the dialer.

So, the next time you are faced with a relay requirement, don’t automatically assume you’ll want an SSR. Modern versions of the venerable electromechanical relay – which has been around for about 150 years and is now highly refined and mature – may actually be the right component to solve your problems with the best set of tradeoffs.

EE World Related Content

Solenoids and relays, Part 1
Solenoids and relays, Part 2
High-voltage, long-life dry reed relays rated up to 200 W
Reed relays capable of standing-off 1.5, 2, and 3kVdc
Reed relays capable of switching speeds up to 1 kHz and billions of operations
Goodbye to conventional solid-state relays? MEMS mechanical switches aim to make SSRs a thing of the past
Don’t rush to choose rechargeable batteries…at least, not yet

References

1. Doran Scales, “Solid State Relay VS Mechanical Relay – Which One is Best?”
2. TE Connectivity, “Electromechanical vs. Solid State Relay Characteristics Comparison”
3. Omron, “Difference between SSR and Contact Relay”
4. Efficient Plant, “SSR or EMR? Select the Right Relay”
5. Happmart, “Introduction to solid state relays and the advantages and disadvantages”
6. Crydom, “Why Use Solid State Relays?”
7. Iowa State University, “Solid-State Relays for Control” (from 1976 but still makes good points)
8. National Control Devices, “Solid State vs Mechanical Relays”
9. Automation Technologies Online, “Solid State Relays vs. Electromagnetic Relays”
10. Phidgets, “Solid State Relay Primer”
11. Glolab Corp., “Relays, The Electromechanical amplifier”
12. IEEE Spectrum, “The Resilience of the Reed Relay”

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