Tag Archives: Tesla

Notes on JB Straubel’s Keynote at the 2014 SEEDZ Energy Storage Symposium

I thought I’d share my crude notes on a very interesting talk about energy storage from Tesla CTO JB Straubel. The slides are available as a PDF.

  • JB Straubel Keynote
    • CTO, Tesla
    • Previously CTO & co-founder of Volcom, specializing in high-altitude electric aircraft platforms
    • Board Member, Solar City
  • Why is Tesla Deeply invovled in Energy Storage
    • EV Battery History
      • Status quo was led-acid in 1995
        • Stagnant performance
      • LiIon made possible Tesla and the rebirth of EVs
        • 4x gravimetric energy density
        • 6x volumentric energy density
        • 2x cycle life
      • Tesla was first to do Li-ion R&D for vehicles in 2003
    • Tesla Roadster 2008
      • Sought to challenge internal combustion vehicles on more than just fuel economy
      • ~2,500 sold
      • Largest battery pack in a vehicle
        • 50kWh +
      • Optimism based on progress of LiIon cells
        • ~2x improvement in energy storage capability of batteries in the decade between EV1 era and the Tesla Roadster
          • 300Wh/litr to 600Wh/litre
          • Accompanying weight reduction as well
        • In talking to companies involved in 2005, they saw no reason for progress to plateau
        • Ten years later, they expect progress to continue for the foreseeable future.
        • 40% improvement between introduction of the Roadster and the Model S
          • ~300 miles range
          • 85kWh
          • Smaller pack than the roadster
        • See this trend continuing for the next 10-20 years
        • Only 10-20% away from being able to compete broadly with the internal combustion engine.
    • Long term goal is to sell millions of cars
      • Energy storage is the biggest factor influencing cost, and therefore, volume.
    • Current offerings
      • Roadster
      • Model S
        • Main focus
      • OEM
        • Toyota RAV 4
        • Mercedes-Benz
          • BClass
    • Model S Battery Pack
      • Scale & Scope have enabled a cost point that is competitive in other markets outside cars
      • Utilities
      • Energy density is a key path to lower cost
        • Automobiles
          • Not intuitive
          • Some automobile manufacturers have tried to cut energy to cut costs.
        • 200Wh/Kg
        • Benefits for stationary storage
          • smaller footprint
          • easier retrofit
      • Current costs and projections are on track
      • Manufacturing volume is important too.
        • Goal to build 500,000 Gen3 vehicles/year
          • using capacity in existing Bay Area Plant
        • Energy storage required to meet that goal is another story
        • In 2013 ~34 GWh of lithium ion batteries were manufactured, but from ~21 GWh in 2010.
        • Tesla’s projects to use 3-4GWh in 2014
          • Approximately 10% of WW volume
        • 500,000 Gen3 vehicles/year will require 10x current, or ~35GWh of batteries in 2020.
        • Gigafactory sized to meet that demand
          • Would still only supply 0.5% of WW new car market.
          • Doubling WW capacity
          • Reengineering supply chain with major opportunity for cost cutting
          • 30% cost reduction by 2017 ramp-up
        • Thinks that the market for non-automotive storage will grow even faster than the electric car market.
          • Grid storage is slow to mature, but once you cross certain price thresholds, it becomes a commodity market that sells on cost savings
        • Approach to cost reductions at the gigafactory
          • Looking at everything, including the sourcing of the raw materials.
          • Materials are a meaningful portion of the cost of cells
          • Plan to use their purchasing power to use demand as leverage for sustainable practices throughout the supply chain (labor practices, energy, etc)
        • Gigafactory
          • 35GWh of cells
          • 50GWh of packs
            • 15GWh for stationary packs
              • 10x of the California mandate
  • Tesla and Stationary Storage
    • ~2012 adapted vehicle pack architecture for residential energy storage packs
      • 5kW/10kWh
      • Originally targeted at people with solar and teslas
      • Slow to scale
        • ~1000 systems
      • People who wanted to play with energy in their house
        • Peak demand management
        • “Islanding” to isolate their system from grid and allow operation in the event of a power outage
      • Experiment with aggregation of systems
        • Coordinated across households
        • Business models are a challenge
    • New experiment is a larger-scale system
      • Module
        • Based on model S pack architecture
          • Different arrangement of modules
          •  Same cooling and management
        •  Two hour-rate pack.
          • 200kW / 400 kWh+
        • “Single skid” unit
        • Roughly the size of a shipping pallet
        • 800Kg
      • Pilot deployment
        • SuperCharger location
          • Big enough to be worth the time
          • Very peaky load
            • Up to 250KWh peak demand from cars
            • <100KW peak from meter
      • Thinks that utility side opportunities are significant
        • Backup power
        • Demand management
        • Scale up of renewables
          • This will be the major driver for storage!
        • Major adjustments needed in rate structures/incentives
        • es- I wonder where trends in peak generation costs vs storage costs cross
      • Large Pilot (2013)
        • “One of the bigger installations”
          • Tesla’s Fremont plant
          • 1MW / 5 modules
          • Manages ~10% of peak demand
          • 100 MW substation with 100kV tie.
          • 1-2% of installed grid-attatched storage
          • In the process of doubling capacity
  • Thinks of Tesla is an energy innovation company, more than a car company.
  • Cautionary note about building for economic sustainability, avoiding dependency on incentive programs
  • Innovation needed in storage management technology and relationship to grid and generation
  • “The stone age came to an end not for lack of stones, and the oil age will come to an end not for lack of oil”
  • Thinks the economics of renewables are already compelling and now constrained by storage
  • Q&A
    • Can the world support the scale up from a primary resource point of view
      • Li-ion are primarily graphite/carbon for anode, nickle for the cathode (for their chemistry). Steel for can, polymers for separators, organics for electrolytes
      • Predictions of shortages of lithium aren’t well founded
      • Thinks there is a bubble in lithium prices, but Li-ion costs aren’t the major contributor to lithium cell costs
    • Have you thought about the policy changes needed to drive this change?
      • They have been building relationships with CPUCs and utities and even state and fed regulators, but it isn’t a big focus.
      • Tesla is an innovation company that focuses on creating products that drive the need for regulatory changes.
      • Utilities are conservative. Automotive experience is demonstrating that this technology is ready for utility use.
    • Recyclability of lithium ion batteries
      • Recycling is being built into the Gigafactory. With enough volume there are great opportunities for materials reuse.
      • Challenge now is that growth is so steep that the volume of cells coming back is so much lower than current production
    • What is the commercial lifespan of Lithium Ion batteries?
      • Lithium ion batteries for the next 5-10 years
      • Not waiting for the next big thing…
      • Lithium ion cells make business sense now, which is why they investing.
      • Looking historically, improvements aren’t necessarily revolutionary.
        • Often it is through incremental improvements to components of the system that can leverage a lot of existing infrastructure for building cells and packs
          • Better cathodes
          • Better electrolyte
          • Better separators
        • Thinks we can double energy densities with better anode and cathode materials over the next 10 years.
    • 18650 vs other formats
      • Thinks people are hung up on form-factor for no good reason
      • At the scale they are dealing in what matters is whats inside.
      • What matters
        • Cost of materials
        • Thermal / Safety parameters
      • Their conclusion is that relatively smaller form factor are a reasonable optimization tradeoff between safety, thermal and cost.
        • Slightly larger than an 18650
        • Cylindrical makes sense from a cost perspective
      • Some applications will have different characteristics
      • Large cells just move complexity inside the cell
    • Deployment plan and pricing metrics for fixed storage
      • Depends on market
        • Residential
          • Leased to customer, bundled with larger offering
        • Mid-market commercial customers
          • Many prefer to buy outright
          • Others want Tesla to provide savings, take care of utility interconnect, etc
          • Some people don’t want to arbitrage their energy
            • He did it at his for a while. Got bored with it
          • Thinks at the end of day, Tesla or a 3rd-party financing company will end up owning most of the packs and be responsible for management
        • Utilities are another matter, given the scale and dollars involved.
    • Have you developed a center to deal with dispatch of modules?
      • They are building it.
    • Failure rate and warranty for modules
      • Quite reliable
      • Automotive application is much harsher
      • Maybe over-engineered for fixed application
      • Warranty rates are great
    • Degradation profile
      • Similar to cars
      • Optimized for 10 year life
      • Avoid paying too much for a product that outlasts the product, or the pack.
    • What are your perspectives on the power converter, are you building it yourself?
      • System design and integration are their major focus, just as with automobiles.
      • The power electronics for Tesla Model S is a very capable starting point for these fixed storage modules.
      • Costs for the power electronics are dropping quickly, will see less than $0.10W very quickly.

Used Tesla 444 cell 6s74p Modules for Sale

Last night, a new member on the EEVBlog forums posted that he had  ten battery modules from a Tesla Model S for sale. The asking price? $1,900 each, shipped within the US.

According to the poster, it is a rev b pack from a car with ~4,000 miles on it. Each module has 444 18650 cells, configured as six in series, 74 in parallel (6S74P). Capacity is 233Ah and 5.3 kWh. Each module has its own Tesla BMS (battery management system), and plumbing for heating/cooling.

I also found another thread about the same modules in in a DIY electric vehicle forum. There is more discussion there, including some testing results by one of his collaborators. And here is a thread on another EV forum where the collaborator posted earlier in the month about hunting down the source pack and break down some of the modules into cells for sale.

Doing a little math, this works out to $4.28/cell, $0.12/Ah and $2.78/Wh. Back in November, I came across a Hack-a-Day interview with the first person I know of to publish a Tesla Model S pack teardown. I noted that he’d paid ~$20 for his pack, which worked out to about $3/cell, so, this is ~40% more expensive/unit, but with the advantage of 1/10th the initial outlay.

The cells in these Tesla packs are a variant of the Panasonic NCR18650 cells. The exact variant isn’t known, and is probably Tesla-specific, but there are NCR18650 cells with similar capacity on the market. Like all 18650 Li-ion batteries, any NCR18650 cells available retail, or in smaller wholesale quantities have passed through a few middle-men, making the wholesale prices hard to estimate. What I do know though is that it is hard to find such cells for less than $6.50. Laptop packs with 9 similar cells are over $100 new, though you can generally find surplus packs for $50 or $5.50/cell. With only 4,000 miles on the battery pack, and given that Tesla treats them pretty gently, the cells in these packs are going to be pretty close to new condition.

Given all this, these modules seem like a reasonable price if you can use the entire module intact.

On the other hand, using cells from these packs individually probably doesn’t make sense. In addition to the effort required to disassemble the module, these cells may need to be wrapped. It is also quite possible that these cells don’t have some of the safety features people expect with 18650 cells, since the pack has other provisions for dealing with cell shorts and overheating.

If you buy any of these modules, I’d be interested to hear about your plans for them. If you’ve seen other Tesla modules for sale, I’d appreciate a link, or information about the pricing.

On the Tesla home battery

During Tesla Motors’ Q4 2014 earnings call on February 12th, Chariman and CEO Elon Musk and CTO JB Straubel talked a bit about upcoming plans for a battery pack for use in homes and business. Musk said that the design was complete, that production was probably 6 months or so away, and that a formal announcement was probably a month or two out.

This isn’t a surprise. Stationary storage is an obvious use for expensive vehicle packs once their capacity and current-handling characteristics are no longer suitable for transportation use. In such applications, they are an obvious compliment to solar panels, like those installed by Solar City where Musk serves as chairman of the board, and which already has a pilot project using Tesla supplied packs. Oh, and Musk has talked about it during another earnings call last spring.

“We are trying to figure out what would be a cool stationary (battery) pack,” Musk said. “Some will be like the Model S pack: something flat, 5 inches off the wall, wall mounted, with a beautiful cover, an integrated bi-directional inverter, and plug and play.”

To read some of the coverage, this is a major threat to the utility industry.  The Verge thinks that “[…]Tesla’s battery for your home should terrify utilities,” though the article appearing under that headline is more tempered in its assessment.

For Tesla’s part, they seem to see utilities as an ally rather than an adversary at this point. Musk and Straubel’s comments during the latest earnings call were prompted by a question from Ben Kallo, from Robert W. Baird (a financial firm). Kallo asked about developments on the storage side of the business, specifically about Tesla’s position on a number of big RFPs for energy storage from utilities.  Musk’s reply was that they were bidding on a lot of RFPs already, and CTO JB Straubel said they were talking to almost all of the utilities. He went on to caution that the time-frames are very long, but that utility storage was getting an increasing amount of Tesla’s attention.

Tesla has other reasons for closer ties to the electrical utility industry too. Tesla’s current cars have a range competitive with a typical gasoline car. To achieve that range, they need a huge battery pack, and the cost of that pack is major contributor to the purchase price of the car.  For longer trips, the Tesla is at a disadvantage. Filling up a gasoline vehicle takes ~5 minutes. Recharging a Tesla to full range takes over an hour at a Tesla Supercharging station, and ~10 hours with a beefy home charging station. If Tesla is going to achieve their ambitions, they’ll have to lower the cost of their cars and broaden access to rapid charging infrastructure. The utilities are an obvious partner on the infrastructure front, and broader access to rapid charging infrastructure can help lower the cost of cars, by making smaller, cheaper batteries more practical.

Of course, if you look for other commentary on this, you’ll find plenty of other articles and blog posts that go at least as far as the Verge’s headline in proclaiming the death of the grid.  Let’s just say, I think those people are wrong.

An Interview with Tesla Battery Hacker [wk057]

Hack a day has an Interview with the guy who got a battery pack from a wrecked Tesla Model S.

One interesting take-away he paid about $20K for it. I think those packs have 6-7000 cells, so that works out to about $3 per 18650 cell.

That’s not bad on a per-cell basis. New old-stock laptop packs with similar capacity cells seem to go for $3-5/cell, though I’ve scored a few for ~$2.25/cell.

Since he was able to use the packs more or less intact, though, $3/cell is a great deal, considering all the labor he saved disassembling packs and then building a large pack for his project.