Posts tagged solar

Pocket Pages 8.7.12: The Invention Swamp

“Where is your umbrella?” he asked, friendly eyes fixed on me from beneath a giant canopy emblazoned with the 7/11 logo. He’s shirtless and soaked, and he has a point. A ruthless series of cyclones has dumped rain on Manila for three weeks straight. Half of the city is underwater. Rainwater is trickling down the insides of my jeans. “I don’t have an umbrella,” I tell him. ”I don’t like them.” He squints at me, and I try to imagine what he sees. A barefoot guy dripping rain in the middle of the street, heavy sports duffel slung over my shoulder. Yiddish mothers take a look at me and bring me a bowl of soup. Fashionable girls cross to the other side of the street, avoiding eye contact. ”You don’t like umbrellas,” he repeats, eyeing my rainsoaked clothes. ”That’s too bad.”

But honestly, I don’t care about my clothes. I’ll dry out soon enough. I care about the forty pounds of aluminum framing, linear actuators, electronics and solar cells inside the shoulder bag. It’s the latest iteration of the pocket factory. The guys in Hong Kong designed and built it, and using a special soldering technique we worked out in the mantis lab, I just got the first soldered, working panels coming off it thirty minutes ago. In an hour, I’ll be boarding a plane to Hong Kong to bring the factory back to the Haddock team (plane tickets between manila and Hong Kong are cheaper and faster than sending a fedex, and we’ve quickly grown accustomed to bouncing between cities and crashing on each other’s couches). But right now, it’s 4:00 in the morning and I’m very wet. Everything in the factory is waterproof, I tell myself, or it can dry out. I turn towards the main road to catch a taxi, and a fountain of water pours down my collar from a neaby gutter. I say that bit about how waterproof everything is, again, and whisper a quick prayer to the invention gods.

The trick to getting this version of the pocket factory to work was a technique that we call Twice-Baked Potatos. In Hong Kong, Shawn, Samtim and Angus built a new, simplified mechanism to place and build up solar cells. Our first mechanism is a traditional placement machine, using a vacuum to pick and place solettes onto a backing and pressurized syringes to add little dabs of solderpaste between the solettes. This new design holds the backing upside-down, covers it with a spray-on glue, and sticks the solettes to the board upside-down. The design is great–it’s much simpler and smaller than the pocket factory we’re working on at the Mantis lab, but until an hour ago, it wasn’t complete. The problem with this upside-down placement is that it’s tricky to get solderpaste onto the solettes. Solderpaste is…well, what it sounds like. It’s a thick mixture of solder particles and flux, and when you heat it up, it melts and holds the pads of different electronic components together. We use a special lead-free, low-temperature solderpaste to electrically connect the top of one solette to the bottom of the next.

Vlcsnap 2012 08 13 15h32m20s36

In our main machine, we dispense the solderpaste with a pneumatic syringe, pushing solderpaste out a needle with a timed burst of high-pressure air. To do that with this machine, we’d have to build a special mechanism that can move the needle over the solettes to squirt on the solderpaste, and then get back out of the way so we can push the next solette onto the backing. It’s not a simple design–in fact, it would be much more complicated than the rest of the design.So we tried something different. A few weeks ago, we worked out the Twice Baked Potato method. Solderpaste has three states: paste, cracker and reflowed. When it’s a paste, it’s smushy and sticky. If you put paste on solettes and then stack them up, they’ll stick to one another in an unfortunate, lead-free menage-a-toi. If you heat the solderpaste up to 150 degrees C, it reflows–the flux evaporates and the solder melts and flows together, forming a small spherical lump of solder. The thing is, once you’ve reflowed a solette, all its flux is gone, and if you try to reflow the solder again, it doesn’t make electrical connections as reliably. The trick is to hit it halfway. At ~100C, the solderpaste hardens to the touch, but there’s still some flux trapped inside. We can stencil on a thin layer of solderpaste onto a solette, harden it by baking it briefly in a toaster oven, and we’re left with a stack of thin solettes than, when you heat them up, will form a solder joint to anything that’s touching them. Bley Joel made fifty of these once-baked solettes today, and tonight I worked through a bunch of them, loading them into the hopper, placing panels and reflowing the panels in the toaster to solder everything together. I’m starting to get complete, working panels where twelve solettes solder together nicely, but I’m stuck on the connection between the solettes and the fiberglass circuit board I use as a backing. I’m just not getting a 100% reliable connection–in fact, I’m lucky to get one good connection between a the solettes and circuit board.

I ruminate on this during the flight, flipping through reflow profiles and thinking about how to get the perfect reflow. Waiting for my baggage at the Hong Kong airport, there’s no doubt which bag is mine. It’s the one sitting on the conveyor belt in a growing puddle of rainwater. The one holding an itty bitty factory that makes solar panels.

pocket pages hong kong, Invention, pocket factory, pocket pages, travel

Pocket Pages 7.22.12: The Pocket Pages Unfold

We’re sitting on floor cushions in the Likha-Diwa restaurant in Manila, planning our kickstarter launch over sour vine stew and banana coffee. We’ve been discussing this kickstarter nonstop for the past four months, and we already delayed it once. Our lives, our labs, and most importantly, our dreams of working as independent inventors are tied up in the outcome of the kickstarter. It’s not the kind of thing you take nonchalantly. This way lies terror and excitement.

For six months now, we’ve been working towards an idea that can revolutionize microsolar, the small solar panels that power our streetlamps, cell phones, home lights and other small electronic devices. We first caught wind of a weakness in micro-solar production during a voyage of investigation and discovery through the world of small, low-cost solar that took us through rotting solar factories in Dongguan to shivering, soaked motorcycle trips across unelectrified tropical islands and late nights working on prototypes in an industrial building in Hong Kong. Six months into our exploration, we believe we can make small solar panels better and cheaper than anyone else in the world. We’ve spent every cent we can scrounge building a small, automated solar factory that can replace sprawling chinese sweatshops. We work with brilliant people from around the world who put their own inspiration into this machine, improving and refining it. Our baby is getting pretty good, now, cranking out solar panels and doing it right. And we’re fucked unless we can raise enough on kickstarter to take this to the next level.

Most advances in solar are 100-million-dollar projects, pushing an idea through years of R&D to get a one or two percent improvement in efficiency or processing. This money comes from giant venture capital firms, banks and grants. Not only is money like that laughably out of our reach, it’s laughably unneccessary. We would have no idea how to spend a hundred million dollars. We’re more concerned with making the machine to build and ship our first solar panels. And to do that, we don’t need millions of dollars. We need enough to let us do our work, pay the few people who work with us, and have the materials we need to do a good job. We tried all of these approaches, and finding each of them to be an imperfect fit, decided to look for funding for our project in a different direction: Kickstarter. Crowdfunding sites like Kickstarter are a tremendous boon for independent people with creative ideas, giving us a way to reach customers directly and get our big ideas off the ground. But if we want our kickstarter to reach people, we have to draw them in, inspire them, and make them excited to be a part of our project. We have to communicate.

And that’s what takes up all our time, now–so, we want to make small solar cheaper and better, making it useful and accessible to billions of people in all walks of life. How do we explain this to the world? How do we excite people? It’s a big goal, but it’s almost too big. People roll their eyes at us like they do when a six year-old child wishes for world peace. Cute and well-intentioned, sure, but c’mon, really!?!–you’re not going to wish for a gameboy? We’re making a factory, not a product. It’s much more abstract than, say, the fancy $100 watch that just raised ten million dollars on kickstarter. Factories are greasy, noisy places that are far away from most people’s lives (excepting Shawn and myself, who only really feel at home if a machine shop is nearby). How do we explain the dream of a better factory and why it matters? How can this hope to compete with the “that’s sooo cool! Buy!” impulse that other, more straightforward Kickstarter products elicit?

We’ve been cranking out scripts faster than an aspiring writer in LA working nights as an usher at the WIltern. We’ve tried to sell a grandiose vision, we’ve tried to make products with the factory that are interesting and consumer-friendly. They all ring hollow. They feel too complicated, or too simple, or too far removed from our desire to invent great clean tech.

Since I started writing, we’ve moved next door to Sara’s, an institution of Manila society filled with crumbling outdoor tables where artisans and students and tricycle drivers drink cheap beer and say what’s on their mind. Stray cats hop up onto the table next to us, viewing the leftover skewers from the last patron’s meal with palpable delight.

What we need for our kickstarter is an idea that’s interesting enough to draw backers in, but that’s close enough to our vision that it doesn’t distract us or make us spend lackluster months making a product we don’t care about just to scrounge up a bit of money. And then it hits us: why not just tell it like it is? We’re not suave enough to come up with a sophisticated campaign, and we’re much better as inventors than sexy product designers–why don’t we tell the story of what it’s like to try and disrupt an industry as an independent inventor? No!–don’t tell the story. Make our backers a part of it. Hold chats, answer questions, write about what it means to be an inventor in today’s world, what we struggle with and our rare victories. Share the tools we use to come up with new solar ideas. We care about invention more than anything, so let’s do what we do best–invent, and invite the world along for the ride.

Yes. I like the sound of that.

Uncategorized micro-solar, pocket factory, production

How Baby Solar Panels Are Born

Four months ago, I started working with Shawn to help make small, low-cost solar products for developing parts of the world. In the process, we visited some solar factories in Southern China to source small micro-solar modules, and we were amazed to find out that EVERYTHING THEY’RE DOING IS WRONG.

Micro-solar is our own term for solar panels that put out less than 25 Watts. Micro-solar is a big idea about a small thing–by cutting up solar cells and rearranging them, it’s possible to make very low-cost, low-power solar to embed in a product. In particular, we’re interested in the ~1W solar panels, the ones that are small and cheap enough to be everywhere. Over the last decade, we’ve become excellent at making ultra low-power electronics, from cell phones that last weeks in standby to LED lights to wireless sensor nodes. Before 2000, we really didn’t have many electrical devices that could make use of a .4W power source. Now, our engineering is more advanced, and there’s a slew of low-power electronics that we can couple with these panels to make all kinds of battery-less electronics. Micro-solar is responsible for everything from solar powered garden lights and portable iphone chargers to home power systems for the developing world. It’s incredibly versatile and useful, enabling a whole class of new, ambiently-powered products, and once there was enough micro-solar production online, a Billion-dollar industry emerged, practically overnight, to make products powered by micro-solar cells. The scale of the industry means that the stakes are high, and there’s a lot of potential imapct and money for the groups that can make improvements in the production of micro-solar and micro-solar-powered products. And that just makes it all the more extraordinary that China is filled with thousands of micro-solar plants, all running the exact same, stone-age process for making micro-solar, and struggling just to stay afloat.

Cell closeup flickr usr unanoslucror

Micro-solar is a Chinese innovation, originally. Nobody even realized that micro-solar was possible until a chinese factory cranked one out one inauspicious day sometime around the turn of the century. All the money and attention had been going to large scale rooftop modules, made at insane speeds by precision german machines. The ‘innovation’ that made micro-solar possible was really just cheapness–cheap people and cheap materials. Micro-solar factories could put together a slew of low-paid workers to slog through the production of a panel, manually working through each of the process steps. The process, as you’ll see later, is dirt-simple, and is rubber-stamped all over Southern China, giving rise to thousands of factories all doing the same thing.

I’ll talk more about this in a bit–for now, let’s take a look at how these panels are made:

All micro-solar cells begin life as a standard 4 Watt silicon solar wafer just like the ones that the girl is reaching for in the picture. Each piece of silicon only puts out a very limited voltage, around .65V with no current, and to make an electrically useful solar cell, the wafer must get sliced up, and the slices wired up in series to increase the voltage to a useable level. This girl is sitting at a laser cutter that traces out patterns on the wafer, scoring the silicon so that it can be broken later.

The girl then breaks each of the slivers off the solar wafer by hand, stacking them up on a tray.

This manual, imprecise process inevitably creates buckets of ruined solar shards.

Once the cells are cut into slices, they need to be joined together. The first step is to solder on thin, tinsel-like conductors onto each cell. This is done entirely by hand. This guy fluxes and solders solar pieces constantly for his 10-hour shift.

The pieces are then backed with pieces of double-sided tape.

After the pieces are backed, another worker peels off the paper backing from the tape and sticks the pieces next to each other on a plastic or cardboard backing.

This worker goes over the cells and solders each cell to the next one, forming an electrical series string. This manual step introduces the bulk of the errors in the end product.

In preparation for epoxy coating, this worker brushes off each piece with isopropyl alcohol, to clean it.

Solar panels, ready for epoxy.

The epoxying is done in a somewhat dusty-free room. Modules are placed on holders, and a transparent glue is gooped over each module and spread about by hand until the module is covered.

The epoxied panels are placed in a rack and loaded into a heating chamber where the epoxy gets cured.

After the panels are complete, another worker uses a halogen lamp to test their current and voltage output. Panels that pass the test are shipped.

So, that’s the process. What’s extraordinary to me about micro-solar production is that it’s a huge operation to run for a tiny margin. A line of ~100 workers will crank out about 300,000 micro-solar modules in a year. Competitive price pressures force factories to trim their margins down to the bone. The largest single cost to the manufacturer is labor, accounting for about 50% of the shipped cost of a panel. But somehow, nobody has refined the process to reduce the labor and increase their margins. About 10% of the end product ends up with a flaw, due to the imprecise, manual production, and has to be trashed, adding to the manufacturer’s operating expenses. But every manufacturer bears the same burden. Manual handling and breaking of cells also produces huge losses of raw silicon, but again, everybody does it.

On top of all this, the end product isn’t that great. Epoxy-covered panels only last three years before the ultraviolet light from the sun yellows and cracks the epoxy covering and tanking the electrical output from the panel. Over three years, panels don’t produce enough energy to make up for the energy that goes into their production. They just become rotting piles of yellowed e-waste. The irony, of course, is that the raw silicon trapped inside the panel is still good–that silicon will last for twenty-five years. The usefulness of the product is limited by the rest of the process, particularly the epoxy covering. But despite the innumerable flaws, inefficiencies, and incentives to improve, micro-solar works well enough to get products into a Wal-mart, and as long as that’s the case, none of the manufacturers out there are touching it.

Seems like somebody oughta fix that.

by Alex at Mantis Shrimp Invention

pocket factory micro-solar, pocket factory, production