open source UNIVERSAL quick swap battery

[flathill]

I think this idea has legs...

We should create our own OPEN SOURCE UNIVERSAL quick swap battery for ebikes and what not

Designed here on Endless Sphere Technology

WE will use 48V solderless 18650 packs so the packs can be upgraded as cell tech evolves

The pack will be baseplate cooled through the negative "terminal"

The negative electrical connection will actually be made to the case cell on the positive terminal side so all electrical connections are on one side

Imagine being able to travel the country and swap in a new 48V battery modules in almost any city

48V is the magic voltage for safety and cheap distribution when we go off grid or micro grid (no conduit or licensed electrician...etc)

One day we will have quick chargers also but battery swapping can happen NOW

Especially convenient for city dwellers who live in apartments

In addition to swap stations with a dozen batteries ready to go at any time we could have anyone sign up to keep batteries at home or work like plugshare but batteryshare. This will enable cross country trips to remote locations

What shape should each module be and in what kWh increment? The modules need to be able to parallel so it is simple to to add more power or capacity to your electric vehicle. In theory they could power anything and the swapping could be done robotically in the future. Right now just a simple handle with a lock release mech for humans (but designed with the future in mind). Ideally it should also be marine grade so they can be used on watercraft but we would need to vote on that given the added cost

The pricing will be free market. Anyone can add to the network and charge whatever they like as long as the batteries are up to spec. If they own the batteries they can set the price. I will have a small free of charge swap station in front of my home with fully charged batteries, but someone who see this as a business opportunity can partner to build large swap stations in public areas and at select businesses. The batteries will have no GPS tracking features but each will have an electronic ID to work with the open source security system to unlock modules from the swap station with your phone. Large swap station operators can buy insurance to protect against vandalism. The network is decentralized with just one standards body: endless-sphere members. Pack versions will be color coded by the handle to enable seamless cell upgrades

 

[Punx0r]

How many people have identical 48V batteries on their ebikes? How many of those are likely to undertake cross-country trips and how often?

 

[Willow]

idealistic. Sorry to burst the bubble but it just won't work. Most production ebikes are running 36V to start with.... then you have to look at form factor. Why should any future frame or drivetrain design be held back by having to conform to an inflexible battery system. It's like asking Apple and Samsung and every other phone manufacturer to use the same battery.

The only way to do it would be through a 'brand'... and franchise. Call into your local CHARGEBUZZ cafe and swap out your BUZZ battery for your BUZZ machine... get a half price coffee, and be on your way.... till you need your next BUZZ.

Start a brand, and franchise it.

 

[Chalo]

I think battery sharing has about as much of a chance as underwear sharing.

Where I think the concept has some merit is in leveraging a dominant cell format like 18650 to consolidate into a modular nominal 48V pack with its own standardized housing, self-contained BMS, and terminals. That way, we can have individual 1P bricks that can be slotted into carriers as simply as cordless drill packs, in whatever quantity the application demands. Having a small unit size would help us distribute weight evenly on our vehicles, and we'd only need to carry as much energy as the trip requires.

The appeal of an approach like that is that it doesn't impose any assumptions about what the end user needs in a pack except the voltage increment. With a versatile building block, users will decide for themselves what they want to build with it. However much the unit takes care of itself is that much less for the user to worry about. How much do we monitor and fret about the packs in our laptops?

Look at the broad popularity in this community of HobbyKing 5000mAh hardcase packs. All they have going for them is physical packaging and a certain economy of scale. If those advantages could be coupled with automatic cell management and a combined mechanical and electrical mounting, and made an open standard format, such a battery unit could become the light EV equivalent of the AA battery or the one pound propane cylinder.

 

[ksithumper]

The power tools guys have the battery swapping down to a fine art.

Would be cool to ride in, click in 2 or 3 or more 'bricks' depending on your need, and ride off.

Bosch is well able to create a modular battery system for e bikes.

 

[zener]

I think battery sharing has about as much of a chance as underwear sharing.

For delivery people or other who drive 10 hours a day it would make sense to swap in secounds to fresh battery. Also for carsharing like concepts.

 

[flathill]

idealistic. Sorry to burst the bubble but it just won't work. Most production ebikes are running 36V to start with.... then you have to look at form factor. Why should any future frame or drivetrain design be held back by having to conform to an inflexible battery system. It's like asking Apple and Samsung and every other phone manufacturer to use the same battery.

The only way to do it would be through a 'brand'... and franchise. Call into your local CHARGEBUZZ cafe and swap out your BUZZ battery for your BUZZ machine... get a half price coffee, and be on your way.... till you need your next BUZZ.

Start a brand, and franchise it.

This is already being done with scooters. The pack is too large for ebikes and it is proprietary. What I am proposing is an open source universal 48V battery that can be swapped into anything. Each 48V module can also be ganged together such that it forms a larger module. This would enable multiple modules to be swapped out with one pull. The batteries have a self contain and self powered electronic latching/locking/ganging system.

I want it to be baseplate cooled such that when the battery is mounted to the vehicle or whatever it can either:
1) operate passively in free air for those in temperate climates year round like here in Nor Cal
2) couple to another base plate with active heating and cooling for those who need it

If you wanted to start a brand that would be fine. The whole point is it is universal and free for anyone to exploit.

 

[flathill]

I think battery sharing has about as much of a chance as underwear sharing.

Where I think the concept has some merit is in leveraging a dominant cell format like 18650 to consolidate into a modular nominal 48V pack with its own standardized housing, self-contained BMS, and terminals. That way, we can have individual 1P bricks that can be slotted into carriers as simply as cordless drill packs, in whatever quantity the application demands. Having a small unit size would help us distribute weight evenly on our vehicles, and we'd only need to carry as much energy as the trip requires.

The appeal of an approach like that is that it doesn't impose any assumptions about what the end user needs in a pack except the voltage increment. With a versatile building block, users will decide for themselves what they want to build with it. However much the unit takes care of itself is that much less for the user to worry about. How much do we monitor and fret about the packs in our laptops?

Look at the broad popularity in this community of HobbyKing 5000mAh hardcase packs. All they have going for them is physical packaging and a certain economy of scale. If those advantages could be coupled with automatic cell management and a combined mechanical and electrical mounting, and made an open standard format, such a battery unit could become the light EV equivalent of the AA battery or the one pound propane cylinder.

Yes you get it with regards to creating a light EV equivalent of the AA battery! The quick swap station aspect is a secondary market. Whether the quick swap station goes mainstream it does not matter. I've gone ahead and edited the title to make that clear. Thanks!

Even if you have no use for quick swap stations...Imagine being able to go into any store and buy and new battery for you bike/scooter/largepowertool/offgridhome/jetskit/whatever. Swap the new battery in in the parking lot. Walk into the store and get you "core charge" back when you give them the old pack. The store could sent the pack away to be rebuilt or properly recycled!

 

[flathill]

The power tools guys have the battery swapping down to a fine art.

Would be cool to ride in, click in 2 or 3 or more 'bricks' depending on your need, and ride off.

Bosch is well able to create a modular battery system for e bikes.

Yes you get it in a way but imagine if the power tool companies all used standard size format(s)

Right now what we need to figure out is what is the ideal size 48V module. 11s1p, 11s2p, or 11s3p, or? What shape should it be?

The microgrids of the future will all be 48V as that is the max voltage you can use without conduit

It is also a safe and practical voltage for ebikes and whatnot

 

[flathill]

How many people have identical 48V batteries on their ebikes? How many of those are likely to undertake cross-country trips and how often?

In the future....almost everyone

 

[liveforphysics]

Maybe 3D printed connector/holders for these?

http://www.dewalt.com/tools/cordless-batteries-dcb205-2.aspx


I think something perhaps more practical would be ebike supercharger stations. Something like Justin's satiator charger scaled up an order of magnitude in power, and mounted in a nice weatherproof housing mounted on a pole in the ground with various charge-plug adapters.

Public ebike chargers are becoming more and more common, at least in China and the Netherlands.

Imagine if every city had a conveniently located public charger capable of 0-100A from 0-120VDC. Show up with an empty pack, hammer it with 3C charge 10minutes, and you've got a half-full pack to get you to the next station or home or whatever.

 

[r3volved]

I think something perhaps more practical would be ebike supercharger stations. Something like Justin's satiator charger scaled up an order of magnitude in power, and mounted in a nice weatherproof housing mounted on a pole in the ground with various charge-plug adapters.

Public ebike chargers are becoming more and more common, at least in China and the Netherlands.

Imagine if every city had a conveniently located public charger capable of 0-100A from 0-120VDC. Show up with an empty pack, hammer it with 3C charge 10minutes, and you've got a half-full pack to get you to the next station or home or whatever.

This

I've had dreams of setting up charge stations since justin introduced the satiator. It a much more practical idea to have a multi-purpose charge station and to standardize connection types.

It's a lot easier and cost effective to engineer a self-analyzing charging platform for people to adopt connectors; as oppose to developing a swappable pack and expect the public to adopt and develop around a standard capacity/voltage/size battery.

There's way less overhead for maintenance, staff, theft, insurance, facilities, etc. there's a lot more growth potential as well as you can evolve your product with new technologies rather than continually reinventing it.

 

[wb9k]

A colleague at work is working on a 3D-printed method of ganging together 26650's in any number of easy modular ways. No solder, all compression fit. We'll see how much current it can support when we have some protos to play with. The printer is pretty cool, but not for the faint of heart. Lots of things to learn, lots of pitfalls. After watching my friend deal with it, I'm both impressed and turned off. I'm definitely not interested in buying an uber-cheap 3D printer that requires a rebuild and constant tweaking just to print square parts.

In the automotive industry, there are standard form factors---lots of them. I don't even know how many "standard" starter battery forms there are out there. There are many.

The European auto industry has recently settled on a standard form factor for Li ion pouch cells to be used in starter batteries. I still expect pack level form factors to vary significantly, but time will tell. Because bike frames vary just like cars do, I would think coming up with a one-size-fits-all solution would be difficult. But if it was modular somehow, it might be workable. It's certainly workable for individuals to make multiple packs that can be quickly and easily swapped.

 

[Willow]

...With a system like the ADAPTO, you can have on-board charging - (fast charge easily at 2KW), just plug into any standard power outlet... public charge infrastructure then becomes very simple.

 

[r3volved]

...With a system like the ADAPTO, you can have on-board charging - (fast charge easily at 2KW), just plug into any standard power outlet... public charge infrastructure then becomes very simple.

That's even better
Just needs to be simpler...and from what I gather, more available.

 

[flathill]

Like I said quick charging for ebikes will happen eventually whether it be DC or AC. We need standardization in a lot of other areas first. Think of this battery module as the first step towards some sort of standardization that will push us to also standardize the connectors in parallel. Forget the battery swapping STATION aspect for now. This battery module will be just like a power tool battery in that it is easy to swap but will have many more features. Also the battery can be used universally in any 48V device not just ebikes. Maybe you want to plug it into your boombox and then into you bike or maybe in a small solar charging station or maybe you need power at a job site for your inverter...

What I'm proposing is basically an standardized open source solderless 18650 cell holder module with some added features:

1) Pressure contacts so it available in kit form (you supply you own cells and build at your own risk so this eliminates any liability risk during the initial deployment).

2) Baseplate cooling/heating. This means one side of the module enclosure has to be aluminum for sure but we may want to just make the whole case aluminum. This outer side of the baseplate can couple to nothing in most useage cases, or another heatsink, or a liquid heat exhanger, or ....The inner side of the baseplate is sinked to the negative end of the cell. See http://www.google.com/patents/US20140234668

3) Can be combine into larger battery packs utilizing the latching feature. Module will hook to other modules. You can use a group of modules laying or the floor to power your house or you can mount the modules to the frame of the device that needs power using the same latching system (ebike or whatever). The latch may be electronic or mechanical. Yet to be determined. The ganging of modules will be space efficient. You can latch onto the frame OR into some compartment on the frame. Paralleling of packs must be using a outside harness or will the ganging parallel the packs? Maybe you will always need some sort of frame anyway even to power you house as it will need a BMS and contactor outside the modules. Have not thought this out.

4) Hidden contacts. No chance of shorting the pack and totally weatherproof. No wires. Maybe the main power contacts could some how be integral to the latching system.

5) Relatively small. I am thinking maybe. 11s2p or 11s1p. 11s2p would yield a 320 Wh module with next gen 4 Ah 18650 cells or 265 Wh with current gen 3.3 Ah 18650 cells. 11s yields 46.75Vmax with current 4.2Vmax cells and allow for up to 4.35Vmax cells in the future given that I'm proposing we set the absolute max limit to 48V, not 48V nominal. What shape is best I don't know. If we put all 11 side by side in a flat row the pack would be a minimum of 201 mm long or about 8 inches long. Any dead space can be used for other features (contacts, etc).

6) Theftproof. Either needs a physical key or electronic key (your phone). This all depends on the latching system.

7) One temp sensor measuring base plate temp (large thermal mass slow to react) and one temp sensor measuring bus bar temp (will react fast and also alert to problems with cell contacts or module contacts).

#8) Cell level fusing

To get the juices flowing:
[youtube]Qf1uafBCaYw[/youtube]

 

[gogo]

Microprocessors and microsensors are the elements that have revolutionized devices. Getting those worked into each module will be the ticket.

You assemble the modules in whatever shape suits your purpose and the interconnects are configured by the system. There could even be microvibrators that optimize corroded contacts. The microvibrators could maybe work together to 3D-target crystals starting to form in batteries. Chicks dig microvibrators. :wink:

 

[flathill]

To start we need to start simple. There will be no contactors or active battery management system inside the module....or will there be?

We could put a batter monitoring system inside the module but there would have to be good reason to increase the complexity vs remote sensing over the BManageS connectors. The BManageS connectors are needed to properly parallel 48V modules in any case so why not monitor from there as well. The only advantage of monitoring inside and then sending over a digital link to a master controller is higher accuracy not dependent on wire length or contact resistance. We don't have to use more wires for the digital link. The module could code it's state (cell voltages and pack temps and ID) onto the main power bus using DC power line communication. The on board monitoring system could also monitor cell aging, useage, et.

Actually I'm probably wrong. An on board battery management system is might be needed. Do we need to parallel at the cell level? Yes if the modules are not matched in capacity due to aging or mixed cell versions. Maybe not if the modules are well matched or we.

How do we ensure each cell in the module will be at the exact same level before they are paralleled? Does this mean we need an interlock system (contactor in each pack). An internal BMS could bleed cells so they match before making the parallel connection but I would like to avoid the complexity and cost if possible. How does Zero do it? They must only parallel at the module level, not at the cell level. Even if the modules are not perfectly balanced at the main output connector the module to module self balance current when paralleled won't really damage anything. If we parallel at the cell level things could easily get damaged from excessive cell to cell balance current when adding another module in parallel if not well matched.

 

[Chalo]

I think the wild card for those in the USA is whether Elon Musk's multibillion battery production plant comes through on projections. If so, theirs is the cell format you want to work with. Other considerations are probably secondary to having that kind of economy of scale and always up-to-date cell technology.

Yes, I think BMS should be at the unit pack level. If that happens, the units become Lego bricks to be stacked up with dumb connections. Without it, the interfacing device becomes a complicated, low-volume gadget in its own right, with lots of room for dangerous mistakes.

I think 36V may be a more practical voltage-- it's safer, adequate in 1S ("smart" packs, not cells) for many applications, and suitable for high performance in 2S configuration.

 

[Eclectic]

A large battery standard would be very nice but…

Normally when a standard like that is developed, it is a consortium of manufacturers and developers (with a dominant company in the lead) and it makes financial sense to the manufacturers to cooperate (like Intel developing PC standards).

Standards like that also tend to be “Black Box”. A set of standard form factors and inputs and outputs but what goes on inside of the black box is seldom specified. As a designer using that standard product, I would actually expect the process inside the black box to constantly improve but the form factor and I/O remains the same (occasional updates to the standard to keep up with advancements). What goes on inside the black box is only the concern of the black box manufacturer not the designer that is using it. Computer hard drives or USB are good examples of this.

The standard should be something like form factor (size), charge connections, discharge connections, data communication connections and protocols (so the controller could interrogate the battery for things like capacity and health and reconfigure accordingly).

An entity like Tesla could drive a standard like that if they decided that was financially advantageous to do so (although Musk might do it because he is a good guy).

Designing what goes inside that black box would be a fleeting standard at best (let’s hope that technology keeps moving forward). Look at how many different battery “standards” have developed here in the short life of this forum. It seems to be moving at about the rate of a new increment every 18-24 months.

The exchange business model works for something like propane because you are talking $4-$5 dollars in product in a $20-$25 container. Enough room for profit and little incentive for fraud. With exchangeable batteries, you are talking about $0.15 of product in a $500 container. Little room for profit and a huge incentive for theft.

 

[Eclectic]

What goes on inside the black box is only the concern of the black box manufacturer not the designer that is using it. Computer hard drives or USB are good examples of this.

2.5" drives are a great example of this. They went from spinning hard platters to all solid state without having to redesign the computers. As long as the "Black Box" (drive) manufacturers kept the form factors and I/O connections and protocols the same, it worked.

Does it make sense to put the smart bits inside the the box? You bet'cha. Otherwise whenever the technology inside the box changes, you would have to change the interface to it. The idea is to keep the interface simple and standard.

As far as voltage and capacity are concerned, I will go back to the hard drive example. It doesn't matter what the capacity or how fast the hard drive is as long as the drive controller can find those things out during the discovery process.

 

[arkmundi]

A colleague at work is working on a 3D-printed method of ganging together 26650's in any number of easy modular ways. No solder, all compression fit. ....

Yea, that's the way to go for sure. I'd love it if A123 corporate would support an open-source modular kit for the 26650 cells, understanding that there is a vast array of potential sizing/shaping issues, but that the ideal cell format for the LEV community would be the 26650. Having attempted a pack build with this form and returned to the less ideal AMP20 prismatic cells, because the making was problematic.

 

[wb9k]

A colleague at work is working on a 3D-printed method of ganging together 26650's in any number of easy modular ways. No solder, all compression fit. ....

Yea, that's the way to go for sure. I'd love it if A123 corporate would support an open-source modular kit for the 26650 cells, understanding that there is a vast array of potential sizing/shaping issues, but that the ideal cell format for the LEV community would be the 26650. Having attempted a pack build with this form and returned the less ideal AMP20 prismatic cells, because the making was problematic.

We tested his first run print today. 100 Amps from a single cell is no problem. The cell gets warmer than the hardware. I think this looks very promising. My friend it pretty excited about this particular project, so I think I'll have more to report soon. The printed parts are OK for testing, but they're really not robust enough for the real world. Once the concept is proven with printed parts, he plans to have a mold made and parts produced by more conventional methods. Stay tuned!

 

[r3volved]

2.5" drive are a great example of this. They went from spinning hard platters to all solid state without having to redesign the computers. As long as the "Black Box" (drive) manufacturers kept the form factors and I/O connections and protocols the same, it worked.

This is highly incorrect...go plug in a solid state hard drive into a windows 95 computer and then report back on how connections and protocols have not changed.

Does it make sense to put the smart bits inside the the box? You bet'cha. Otherwise whenever the technology inside the box changes, you would have to change the interface to it. The idea is to keep the interface simple and standard.

This is also backwards...
You want your 'common/swap' parts as dumb as possible. THIS is how HDD's work...the brains are not in the HDD, the brains are in the PC in the form of driver commands to interface with the HDD's hardware.

As far as voltage and capacity are concerned, I will go back to the hard drive example. It doesn't matter what the capacity or how fast the hard drive is as long as the drive controller can find those things out during the discovery process.

This is again incorrect in the application of batteries; you MUST increase the size of the container to increase the total number of cells. HDD manufactures have developed alternate methods to maintain form factor while increasing capacity...primarily through laser size.

A 'smart charger' should be able to interface with a 'smart bms' to establish capacity, chemistry, voltage limits and charge rates. The dumber the battery pack, the easier it is to 'hot swap' with a smart interface...like a computer does...
computer is smart - hardware is dumb

 

[flathill]

Sorry I'm not waiting until 2020 to get my hands on some gigafactory cells. 18650 is the best cell format to standardize on TODAY. I have even decided two layers of 18650 cells is too thick so any 2P configuration is out the window given the base plate cooling. 26650 cells are also too thick and are realtively uncommon compared to 18650 cells.

The two low voltage DC micro grid standards are 24V and 48V. I've to make the new battery module 24VDC nominal and allow the modules to be parallel or put in series.

This means 6s1p. Which will be suitable even for skateboards or other devices where you need low profile.

The latching/locking mechanism will be actuated on the frame side by the bus bar. The bus bar will be two long strips of rectangular copper. The module will be keyed but can go in both ways on the bus bar. It has to be keyed since both the bus bars and contacts will be symmetric too allow for reversing the mounting direction. The frame side will determine if that means parallel or serial connections with a receptable for the key. The bus bars will spread apart to lock the modules in place and make contact. There this also mean the bus bar can be 1mm thick or up to maybe 5mm thick

The modules will have a built in Battery Management System but no contactor or solid state relay (too expensive). All communication to the master controller will be done over the DC bus. There will be no other connectors besides the positve and negative terminal which will not be exposed.

I plan on 18650 cells being around 2-3 dollars per cell pretty soon. This mean $12-18 bucks per module for raw cell cost. This means we need to get the total cost of the cell holder and the BMS (the universal quick swap battery) to under $6 dollars per module in the long term. At first each kit(not including the cells) may cost maybe 10-20 bucks until we get volume discounts.