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Li-ion cell provider XALT Energy partners with Williams Advanced Engineering

Williams Advanced Engineering, the engineering services and technology business of the Williams Group, has entered a partnership agreement with XALT Energy, supplier of the lithium-ion cells for the Williams’ battery in the Formula E racing series. This new partnership will also see the two companies collaborate on future projects involving lithium-ion battery technology for a range of applications beyond motorsport.

Williams Advanced Engineering and XALT Energy have worked closely together since June 2013 after Williams was awarded the contract to produce the batteries that will power all 40 cars competing in Formula E, the world’s first fully electric racing series.

XALT currently offers a range of high-energy and high-power Nickel Manganese Cobalt (NMC) prismatic Li-ion cells with capacities from 25 Ah up to 75 Ah.

Gravimetric and volumetric densities of XALT Energy’s current line of Li-polymer cells. In the designation HE xx, xx is the capacity in Ah of the cell. Click to enlarge.

XALT Energy have supplied the lithium-ion cells for each battery and have been integrated into the Williams team to ensure that the batteries meet stringent performance, reliability and safety criteria. FIA regulations state the cell weight has to be limited to 200kg and the output of the battery can be no more than 28 kW/h, so Williams designed a battery with some excess stored energy levels that stayed within the FIA regulations via the incorporation of XALT Energy cells.

As part of this new partnership agreement XALT Energy will become an Official Partner of Williams Advanced Engineering, with the company’s logo featuring on the Williams Advanced Engineering website and other marketing materials.

MBP Investors, LLC, an affiliate of Townsend Ventures, LLC, is the majority owner of XALT Energy. Townsend Ventures, LLC is the sustainable energy-focused division of Townsend Capital, LLC, a privately held investment firm based in Maryland.



How will they develop their batteries when the limit is preset at a low 140 Wh/Kg?

Something does not make sense!


Harvey, you're reading it wrong. That is the weight LIMIT. They can go below that weight.


No...they limit both the battery storage total capacity at 28 kWh and its weight at 200 Kg = 140 Wh/Kg.

Tesla-Panasonic already do almost twice as good as that?


It's a terminology issues. They aren't saying they are limiting the total amount of power able to be stored in the batteries but rather limiting the total amount of power drawn from the batteries in a time period during a race and also the total amount recoverable from regen.



Harvey, read it again and think of it as the battery can be "no heavier than" 200kg.
It's the same as boxing, wrestling or mma....the weight divisions are worded the same. Each class has a weight limit.
You're thunking of it like the minimum weight in a racecar class or jockeys.


Well....who would install a larger (40 to 85+ kWh?) battery if you are limited to draw only 28 kWh (**) from it.

I thing that 28 kWh is the real limit here. However, one could always make it much lighter? With less weight it could go further and faster?

(**) It would be like installing a 1000+ hp ICE and limit it to 200 hp?


Actually, it would make sense to have more like 34kWh available but limit it to only 28kWh of USE during a race. That way you're only using about 80% of the capacity and not damaging the battery packs so quickly.

It would also make sense as to why they're looking at an energy density of about 170Wh/kg.


You CAN make it lighter than 200kg. You just can't have more than 28kWh available. So does that mean you could simply scale down a Tesla battery and do it for around 100kg?

Probably not. 28kWh is a total ENERGY limitation, not POWER. These batteries will be delivering hundreds of kW peak output; conversely regenerative peaks will be at a similar order of magnitude. And these discharge/charge cycles occur back-to-back within seconds of each other.

Design considerations are now primarily driven by power density and thermal limits, and a scaled Tesla battery probably isn't in the game. I am a frequent critic of Tesla but not of their batteries. They are terrific -- but they are not designed for this mission.

Safety is also a consideration. Kinetic energy is function of velocity squared. At 350km/h, a battery located on the same horizontal plane as the driver and fuel (and in VERY close proximity) needs a whole different approach to impact protection as well as cell separation and fire suppression. Don't forget about repeated cornering forces of 3.5g or more. Finally we don't really know what the term "battery" comprises. It might also include any dedicated cooling loops and associated hardware, fail-safe contactors, etc.

Viewed in this context 28kWr in 200kg is probably more challenging than it looks from here.


Ooops, but I was just told by kid looking over my shoulder that the weight limit is in fact cells ONLY. So ancillary system weight is moot.


Yes, 34 kWh makes sense to get 28 kWh, if allowed. However, an accurate power limiter would be required to reduce maximum draw to 28 kWh., regardless of the battery's total storage capacity.

The 200 Kg weight seems to be a allowed Max but nothing would prevent making it much lighter.

Racing cars have strict rules to adhere to and to avoid jungle wars.


" an accurate power limiter would be required to reduce maximum draw to 28 kWh., regardless of the battery's total storage capacity." I agree, and it would not be easy to make a tamper-proof implementation.

This statement from Williams (quoted exactly in Mike's article, so no slight on GCC) makes no sense: "Williams designed a battery with some excess stored energy levels that stayed within the FIA regulations via the incorporation of XALT Energy cells"

As Aha

Minimum weight (inc driver): 888kg (batteries 320kg)
The amount of energy that can be delivered to the MGU by the RESS is limited to 28kwh. This will be permanently monitored by the FIA.

A Rechargeable Energy Storage System (RESS) is a system that is designed to propel the car via the electric motor. In order to comply they must be:
- FIA Standard
- The maximum weight of the Battery Cells and/or Capacitor of the RESS must not be higher than 200kgs
- All Battery Cells must be certified to UN Transportation Standards as a minimum requirement

so 140Wh/kg cells minimum, but 87,5Wh/kg battery level maximum?...

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