Automotive

BMW rips the battery out of the i3 and hangs it on your wall

The 2017 BMW i3 uses a larger 33-kWh lithium-ion battery (vs the 22-kWh battery in earlier models)
The 2017 BMW i3 uses a larger 33-kWh lithium-ion battery (vs the 22-kWh battery in earlier models)
View 2 Images
BMW explores an i3 battery pack-based home energy storage system
1/2
BMW explores an i3 battery pack-based home energy storage system
The 2017 BMW i3 uses a larger 33-kWh lithium-ion battery (vs the 22-kWh battery in earlier models)
2/2
The 2017 BMW i3 uses a larger 33-kWh lithium-ion battery (vs the 22-kWh battery in earlier models)

Electric vehicle manufacturers are eager to give their cars another selling point by using them to put electricity back into the home and grid, not just pull it out. Tesla has the Powerwall and Nissan Leafs have been used in car-to-grid programs in the US and UK. BMW is continuing its own efforts by developing a system that could repurpose old i3 batteries for home and business energy storage.

Revealed at this week's Electric Vehicle Symposium & Exhibition 29 in Montreal, BMW's electricity storage and management concept relies on the i3's battery to serve as a backup battery for home or commercial energy. BMW says it's the first automaker to utilize a complete high-voltage EV battery in this way (Tesla's Powerwall uses a battery much smaller than the ones in its cars). The home system, which also includes a voltage converter and power electronics, is designed to be integrated seamlessly with solar panels and charging stations.

In practice, the system looks to work like other solar systems with battery backup. Solar panels charge the battery, and real-time supply/demand energy readings are used to determine when to charge/discharge the battery, minimizing waste and reducing energy costs. The battery would also serve as a backup energy source for use in power outages, and BMW reckons that the original 22-kWh pack or all-new 33-kWh pack could run a variety of appliances and entertainment devices for up to 24 hours.

BMW explores an i3 battery pack-based home energy storage system
BMW explores an i3 battery pack-based home energy storage system

"The remarkable advantage for BMW customers in using BMW i3 batteries as a plug and play storage application is the ability to tap into an alternative resource for residential and commercial backup power, thus using renewable energy much more efficiently and enabling additional revenues from the energy market," explains Cliff Fietzek, manager of Connected eMobility at BMW of North America.

There's nothing groundbreaking about the system's design, but what is interesting is that BMW sees it as a way of reusing old i3 batteries that still have some life left in their cells. BMW claims that the i3's lithium-ion batteries will retain most of their original capacity after use in the vehicle and believes they'd offer many years of in-home service. The system could also use a brand-new battery pack, if the home or business owner preferred.

BMW doesn't mention any immediate future for the system, but it will be trialling a related energy system within the two-part ChargeForward study being conducted with California's Pacific Gas and Electric Company. Second life MINI E batteries will be used to create a stationary solar energy storage system at BMW's technology office in Mountain View, California. The second part of the program will task participating San Francisco Bay area i3 drivers with allowing BMW to delay or interrupt vehicle charging by up to an hour in response to peak grid loads. The purpose of the study is to demonstrate how intelligent EV charging management can help optimize power grid efficiency and reduce the cost of EV ownership.

Source: BMW

9 comments
Gary Duff
Great idea and definitely the way forward for the future of distributed electrical storage. Why does it need to be hung on a wall though? Surely it can form part of the general grid electrical storage system while it's still fitted in the car. That way it can be part of the grid wherever it is parked and plugged in which for most people is at their place of work during the week days at least. Cars are parked up 95% of the time anyway so enabling their use as a fixed storage device is a no brainer and something that will end up happening at some point in the future. Ultimately I can imagine battery owners being paid by the grid/ distribution operator for using your battery to regularise demand as required whenever plugged in and available. This will also enable a much deeper penetration of intermittent energy sources such as solar and wind energy.
S Michael
And the power monopolies are going to let you do this..... I don't think so.
DaveWesely
This is nice, but really only a baby step in the right direction. We need to be able to swap industry standardized batteries in and out of the car. The i3's batteries weigh about 450 pounds, or about 60 pounds per cell pack. So you have several electric vehicles, one for long trips, and a couple around town commuters. When the family needs to road trip, pull the extra batteries out of the commuters and pack them into the road tripper. If you need more range, stop at a "gas" station, swap out the depleted cell packs for fresh ones and be on your way. Or if in need of more range, buy an aluminum oxide single use cell pack. Creating an industry standard form factor would stimulate battery development even more than limiting vehicles to proprietary systems, even if the batteries can be repurposed after the cars end of life. And create better market efficiencies.
Gary Duff
Wait and see S Michael.... The power monopolies you talk about hate having to balance power demand, distributed storage will help them be more efficient. The world is going to have to wean itself off fossil fuels one day like it or not and this is how it will be made possible.
S Michael
Gary D. I'm with you, but the power people are not going to give up their golden goose just so we can power our home, car, boat or whatever. Nope we will have to pay... just like the people today are paying for there solar panels and power. Remember, it not the cost of electricity that is expensive it the "Transmission" cost, so they claim.
Daishi
As rates for electricity start to fluctuate greatly based on time of day because of the way green sources deliver power it should create a market for grid storage that will drive innovation. In the short term though people are likely going to use storage just to serve their own households to avoid paying the utility higher evening rates. i'm not sure if I envision a day where the utility would ever be willing to pay me enough money to make it worth using my own expensive electric car to help them with demand. In a future world electric car companies with long battery warranties probably won't be too thrilled about the battery they hold the warranty on being used to serve the utility. It's just right now that they don't care about it but later on it's the kind of activity that could potentially void future warranties.
vernwrites@gmail.com
If I'm reading this correctly, BMW batteries have to be well charged to be used in the car and the batteries they are using have a limited useful life. After that life is used, the batteries can be used to 'serve' the utilities. I'm curious what the replacement cost is for the batteries that are put into the car to replace those that are not adequate any longer? I'm not into electric vehicles so this is just curiosity, but my friends who have Priuses seem to be able to use the things forever without battery replacement. My question is this: I this another case of BMW selling an image (You know; the, 'I've got a Beemer folks,' who also spend $200 for tennis shoes?)
Noel K Frothingham
S Michael, is that so? Your so-called power monopolies have been working on something similar (sodium ion batteries) to store low cost energy for use during peak demand periods. This BMW battery 'repurposing' initiative makes a lot more sense in terms of safety (liquid sodium reacts violently when exposed to air) even though there is a loss in energy density. Save your omniscience complex for a more appropriate time and place.
Tom Lee Mullins
I think that is a good idea if one has a small house. It won't need a lot of electricity. One could put solar panels, solar water heaters and other forms of power generators on or about the house.