FAQ

About Tanktwo

What is the idea behind Tanktwo?

Tanktwo is a battery technology startup, and was founded in 2012. It has the specific mission to drastically improve EV battery performance by applying established principles from other industries. Most inspiration comes from 2G, 3G and 4G mobile networks, internet routing protocols, and consumer electronics industries. We follow a strongly data-driven method for making batteries perform significantly more work.

Tanktwo chose to pursue this path because despite decades-long billion-dollar level investments in battery development, the users of batteries are very far from satisfied with the current levels of battery performance. Instead of trying to force Nobel-prize breakthroughs in battery chemistry –or hoping for someone else to do so – we started looking for other improvement opportunities. The good news is: there were many.

Who are the brains behind Tanktwo

Tanktwo is run by a team of seasoned executives from the telecom, consumer electronics and FMCG industries; and the products are developed by the smartest geeks on the planet. Key persons are listed on the Team page

Where is Tanktwo located

The company has several offices all over the world. Please have a look at our contact page for more information.

Battery Technology

What is the current status regarding the Tanktwo String Cell Battery?

Tanktwo makes components that need to be integrated into consumer products. We have designed and implemented functional prototypes for evaluation by our potential customers. These prototypes have all the functionality needed for customers to determine if this technology is right for them. In the meantime, R&D for next generation products is ongoing as well. These products have higher power density and work faster, but they are fundamentally the same as what we have today.

We are periodically opening investment rounds to scale up our operations and work with more customers in parrallel.

Are you interested in an idea that would compliment your technology?
What are the weak points of your system?

As with all new things, doing things differently (even if different means better) requires changes in people’s behavior, expectations and thinking. Tanktwo battery technologies are solidly based on already existing technologies. This means that no further cold fusion, or revolutionary battery chemistry needs to be invented to turn Tanktwo battery packs and units into mass products. However, vehicles are expensive and they play a very important role in people’s everyday life. For this reason, they are expected to function flawlessly and without any problems. Our industry customers also have a large impact on how the end-user experiences the new technology, as the battery system is merely an enabler to make your car move. That said, we think that our technology truly has many advantages, and few negatives.

Why has nobody come up with the idea before?

Sometimes it helps to have a fresh perspective. The guys who cooked up the concept have backgrounds in telecommunications and other non-battery industries. Once you realize you can employ telecom technologies on batteries, a new world of possibilities opens up.

I only need my EV for short commutes. Why would I consider the Tanktwo String Cell Battery?

Actually, there are many ways that you can benefit from Tanktwo battery technologies. First of all, you can adjust the battery capacity for your needs, saving on purchasing cost and eliminating the need to carry any extra capacity and weight with you as you travel. You will still have complete freedom to change your mind and update the capacity after the purchase of your vehicle, which is certainly not possible with traditional EV battery packs. Also, you are future proofed against battery malfunctions and technology improvements, because you can go and swap your battery units any time you choose to do so.

Typically, when the battery pack malfunctions, it is just one or a few cells that are problematic. In most of the traditional battery packs it is very difficult, or even impossible, to just change individual cells. In almost all cases, your only option is to change the whole battery. This can be an extremely expensive affair, if it is feasible at all. With the Tanktwo String Battery, the opposite applies: identifying and replacing a cell is fast, easy and quick.

Besides, along with the benefits mentioned above, an EV with a Tanktwo battery pack works just like an electrical car with a regular battery pack – no sacrifices or changes in user behavior are needed.

Will the Tanktwo String Cell Battery affect the performance of my car?

There are several reasons why Tanktwo’s string battery can give better performance than traditional EV batteries. Compared to a regular EV battery, you can load the string battery with the amount of string cells you actually need. This might mean a lighter car by several hundred kilograms, resulting in much better performance. String batteries can also utilize the string cells in an order which provides the most power output. The cells will be used as efficiently as possible, making the string battery at least as powerful as a traditional EV battery.

Does the tank of my car has to be bigger for the Tanktwo String Cell Battery?

Not quite. Current EVs use batteries that are equivalent to 2000 to 8000 string cells, giving range of 150km to 500km. This volume-capacity ratio is better or equal compare to current EVs. Furthermore, minimizing weight is usually much harder than minimizing volume in the design of a vehicle.

Can the Tanktwo String Cell Battery also be used for other EVs like scooter or ships?

While personal cars are the most commonly advertised electric vehicles today, we haven’t limited our solution to cars. Our string battery can be designed for large and small vehicles, and you can also use multiple string batteries in a single vehicle. Basically Tanktwo batteries can be used for any solution, which is using batteries to store energy.

How does the Tanktwo String Cell Battery create power?

The string battery contains multiple string cells, that in turn contain an electrochemical cell. The string battery maps the string cells and decides the best way of connecting them together. The electrochemical cell inside a string cell has polarity, positive and negative. The string cell has an internal processing unit that can connect the positive or negative terminal of the internal cell to any of the contacts on the string cell surface. The electrical power is produced by the internal cell, but the string cell routes the power to any of the outside contacts, according to the routing plan received from the string battery.

How long does it take to swap the Tanktwo String Cell Battery?

The time for cell swap is under 3 minutes.

How is the Tanktwo String Cell Battery different from other battery swapping ideas?

A little note about revolutionary battery technology research: Usually these press releases are about technology research in the very early stages. To the reader, they often sound like something that is ready for production in a few years. In many cases, these technologies will never be realized. We hope that sooner, rather than later, some of them will come to fruition. This will make everybody happier, including us at Tanktwo. Tanktwo battery technology is different in a way that it does not rely on any new unverified or uninvented ideas, it only needs engineering to be perfected.

There are several battery swapping ideas, most of them have been literally tackling the swapping part, but haven’t introduced any other value. Even if they have shown working prototypes, some of the ideas other properties are just not feasible for technical or economic reasons. Often, the problem is the inflexibility of the one-battery-must-fit-all approach. With Tanktwo technology there isn´t this problem. Difference is that Tanktwo technology enables cell swapping (instead of whole battery). Cell swapping is a method of replacing electrochemical cells placed inside the battery enclosure. This brings also many other benefits.

Is Tanktwo just another battery swapping method?

Cell swapping differs from traditional battery pack swapping technologies in that only the cells are swapped. Cell swapping is one, and maybe the most notable, property of the Tanktwo string battery system. While the possibility to swap the cells for new, fully charged ones is important, other properties of the system might be even more beneficial. Compared to traditional monolithic batteries, the benefits include:

  • More power out of the same battery capacity
  • More kWh out of the same nominal capacity, without compromising battery wear and aging
  • Possibility to carry/own only the needed battery capacity. The great majority of vehicle use cases is short-distance commuting, which can be done easily with only 50% of typical range/battery capacity. This, in itself, already saves more than 200 kg/500 lbs of the vehicle’s gross weight. This is equivalent to the weight of 3 additional adults on board. The decrease in weight saves a substantial amount of money and extends the range per capacity
  • Less expensive vehicles can be sold with much smaller battery capacities. The extra capacity for longer trips can be leased / purchased as needed and returned when no longer needed.
  • The obvious benefits of extending range by swapping battery cells at service stations offers a familiarity to the refueling process we are used to with gasoline propelled vehicles.
  • No worries about an aging battery, or malfunctioning single cells. The cells can be easily swapped any time for a new one and malfunctioning single cells will be replaced automatically. This in no way affects the system function because of the complete redundancy of the system. Users can be completely unaware of the process, even if 10% of cells are not working at all.
  • Being future proof for new battery chemistries – Most of the changes in battery unit design can be covered with a software update, or even without it.
  • Possibility to take cells easily into use for other applications e.g. when cells are not good enough for car usage when capacity has dropped, cells can be used for stationary energy storage.
Are the costs for a kWh higher than for traditional battery packs?

Perhaps surprisingly, that is not the case. Tanktwo’s battery cost per kilowatt hour is actually less than that of traditional battery packs. It is true that each Tanktwo battery unit contains sophisticated electronics, but all that technology is fitted into one integrated circuit chip, equivalent to less than the size of a finger nail. In contrast, traditional battery packs require huge amounts of mechanical parts, like screws, bus bars, connectors etc, to secure them. Often, thousands of individual cells are required to form the exact battery circuit required. On the other hand, Tanktwo battery packs are mainly a container for the individual battery units that together form a random circuit network, from which almost any kind of cell circuitry combination can be formed.

Why isn't the Tanktwo String Cell battery cubicle?

Currently, the shape of the battery unit is ellipsoid with a special semi-axis ratio. This configuration offers special properties, including the best known possible random fill ratio, that creates a high number of contacts between the individual units. This ensures that even if the units are just poured into their container, they always fill the space in the best possible way, making it very hard for them to move in relation to each other.

Why is the Tanktwo String Cell ellipsoid?

The current shape of the string cell is ellipsoid. This shape offers some very special properties, compared to a sphere. For example, the ellipsoids fill the container better and while in the string battery, they move just as easily as spheres. You are certainly right that spheres would roll better though. Please read “Question: Why the battery units are not cubical, you could fit much more capacity in same space?“ for more detailed information.

What battery chemistry is the Tanktwo String Cell using?

Currently, the battery units are based on lithium-ion chemistry, but basically any chemistry can be used in the system. While it is not perfectly optimal, one could even fill the Tanktwo string battery with mix of units using different battery chemistries.

How many string cells contains a Tanktwo String Cell Battery?

Tanktwo string batteries can be built small or large. Typical vehicle packs contain anything between 1,000 and 10,000 string cells. Additionally, if one has a string battery that can hold 8,000 string cells, he or she can decide to fill it with, say, only 2000 string cells.

What is the battery output voltage?

This is actually a multifaceted question. The string cells inside the Tanktwo string battery form many serially connected individual battery circuits that have a variable amount of cells in them. The voltage of these circuits could, for example, vary from 50 V to 150 V. These voltages are then converted to a voltage level that is desirable for the vehicle’s power electronics. Thus, the answer, in short, is that the output voltage can theoretically be almost anything, but it typically ranges from 100 – 600V.

Battery Safety & Sustainability

Is the Tanktwo technology green and clean?

Our string battery technology promotes green values in many ways. Our solution reduces the weight of the battery, saving on emissions and resources. It also makes recycling unusable electrochemical cells an automated process, read more about recycling in “Question: Are the Tanktwo batteries recyclable?“. The components and materials used in our products are designed to be fully recyclable. Additionally, the Tanktwo String Cells do not need to be retired when their capacity has dropped below a certain level, such as 70%, and can therefore have a longer useful life.

Is the Tanktwo String Cell Battery recyclable?

They certainly are. To be more specific, the string cells are designed to be recycled automatically when their performance goes under a predetermined threshold. The cell swap technology enables automatic analysis of the state of every string cell. This means the string cell is recycled only when it’s no longer usable for storing electricity. In addition string cell can be easily used for several different applications e.g. for an EV or stationary energy storage. This maximize the lifetime of one cell.

Will the Tanktwo String Cell technology be obsolete in a few years?

To the contrary. Cell Swapping is only one property of the system. Please read, “Question: So, this is basically just another battery swapping method?“ to find out why the Tanktwo battery system still beats the traditional monolithic battery long after batteries. Also, better and faster charging battery cells benefit the Tanktwo battery system like any other battery system, thus better cells are always welcomed.

It is true that there are many battery technology developments ongoing and several parties have published groundbreaking press releases about quickly chargeable batteries. Unfortunately, very few of these technologies have materialized, for many reasons.

Are the Tanktwo String Cell Battery safe to use?

A single string cell contains only a small amount of lithium, rendering it very safe. In the case of a malfunction or severe accident, the string cells disconnect the internal cell from the outside contacts. This makes it impossible for the cell to short circuit, or otherwise load the internal cell. In addition with String Battery it is possible to have a detector which is configured to detect a hazardous condition of the cells, and have a release system to release the cells as there isn´t fixed mechanical connection between the cells. After releasing the cells, they are mechanically separated from each other thus chain reaction is not possible, preventing the possibility of an electrical fire.

Deactivated string cells can be handled like any bulk material. They can be scooped or poured from container to container, and they don’t pose a risk of igniting by themselves.

Can driving through a pothole cause a malfunction of the Tanktwo String Cell Battery?

A little note about revolutionary battery technology research: Usually these press releases are about technology research in the very early stages. To the reader, they often sound like something that is ready for production in a few years. In many cases, these technologies will never be realized. We hope that sooner, rather than later, some of them will come to fruition. This will make everybody happier, including us at Tanktwo. Tanktwo battery technology is different in a way that it does not rely on any new unverified or uninvented ideas, it only needs engineering to be perfected.

There are several battery swapping ideas, most of them have been literally tackling the swapping part, but haven’t introduced any other value. Even if they have shown working prototypes, some of the ideas other properties are just not feasible for technical or economic reasons. Often, the problem is the inflexibility of the one-battery-must-fit-all approach. With Tanktwo technology there isn´t this problem. Difference is that Tanktwo technology enables cell swapping (instead of whole battery). Cell swapping is a method of replacing electrochemical cells placed inside the battery enclosure. This brings also many other benefits.

Purchase & Costs

Where can I purchase Tanktwo battery products

Demo units are up and running for evaluation in our offices and with select industry customers. As of today, Tanktwo battery technologies are in the development stage, and are not yet available for end-user purchase.

Based on the current plans, however, there will be a number of pilot systems for day-to-day testing in 2018. We will announce when these systems are made available for end-user testing.

Do I own or borrow the Tanktwo String Cell Battery?

This is a question that touches on the economics of the string battery ecosystem. You can buy string cells from a car dealer when purchasing a new vehicle. Then, the ownership of the string cells is yours. If you drive to the service station to exchange the string cells you own, the ownership is exchanged also. The value of the string cells you own will be calculated, as will the value of the string cells you receive. You will be charged with the price difference of the string cells, and you will obtain ownership of the new string cells you just bought. The old string cells you owned become the property of the service station and will be given to other users later when they are sorted and recharged in the service station. If the string cells you handed in were more valuable than the string cells you received, you will receive a financial credit.

To make longer trips, you can fill your tank to capacity, even if you originally bought only half a tank of string cells to support the daily commute. To buy the tankful of string cells, you can pay for them and you will get back the exchange value when you revert to a lower number of string cells. It is also possible that several financial companies are interested in effectively loaning the money for a tankful of string cells for the time you need the full capacity. This is a consumer credit transaction for which many frameworks already exist and an industry with plenty of players. In essence, boosting your battery capacity for the weekend is analogous to renting a car for the weekend.

Notice that the service station where you fill up and the service station where you return the candies does not have to be the same. You can alter the capacity of the string battery at any time, according to your needs.

What is the price of the Tanktwo String Cell Battery per kWh

The price of Tanktwo battery capacity always closely follows the cost of the battery chemistry, which for the foreseeable future is lithium-based. The additional cost of the battery pack comes mainly from the battery unit’s integrated electronics; which at the appropriate scale, is marginal.

Electric Vehicles can be sold from the factory equipped with cells for 150 km of range, covering 95% of typical use, but can be upgraded on demand to 500 km when needed or all the smart cells can be swapped fully charged ones in less than 3 minutes. This ensures both a low price and “gas car range” capability. The result is an EV with a capability for a 500 kilometer range, but packed only with 150 kilometers worth of batteries for daily commute, creating an exceptional cost advantage.

Are the costs for a kWh higher than for traditional battery packs?

Perhaps surprisingly, that is not the case. Tanktwo’s battery cost per kilowatt hour is actually less than that of traditional battery packs. It is true that each Tanktwo battery unit contains sophisticated electronics, but all that technology is fitted into one integrated circuit chip, equivalent to less than the size of a finger nail. In contrast, traditional battery packs require huge amounts of mechanical parts, like screws, bus bars, connectors etc, to secure them. Often, thousands of individual cells are required to form the exact battery circuit required. On the other hand, Tanktwo battery packs are mainly a container for the individual battery units that together form a random circuit network, from which almost any kind of cell circuitry combination can be formed.

Charging

How do you ensure an infrastructure with enough charging stations?

Tanktwo String Batteries do not require any new infrastructure to be useful, beyond the normal maintenance tools at authorized OEM maintenance centers. However, it is true that Tanktwo systems can provide enormous end-user benefits when at least some service stations are in operation. It is good to remember that the number of stations required to see benefits is drastically smaller than gasoline stations, and benefits can start with a single station. Most of the time, Tanktwo batteries are charged just like any plug-in EV.

Can I also charge the Tanktwo String Cell Battery at home?

A vehicle with a Tanktwo battery system can be charged just like any plug-in EV. Swapping the cells at service station is a complementary way to charge the battery, and can be seen as a super-quick charge option; a cell swap takes less than 3 minutes. Another reason to charge by cell swapping tre the economic benefits: Batteries at the service station can be charged when the cost of energy is at its lowest, for example during the night. This way stations are able to offer greater cost benefits.

How long does it take to swap the Tanktwo String Cell Battery?

The time for cell swap is under 3 minutes.

Why would I want to go to a service station to swap the Tanktwo String Cell Battery?

In larger fill stations you have an option to choose the battery unit quality, similar to the way you choose the octane grade in gasoline stations. When you empty and refill your string battery, you will be compensated or charged, depending on what kind of battery units you are leaving to, and getting from, the fill station. The service station and each individual string battery know the current value of the string cell; which is based on the battery type, age, use history and charge status, amongst other factors. After a swap, you just pay the difference between the values of the swapped string cells. In this way no party is ever disadvantaged by a string battery a transaction.

EVs equipped with traditional batteries suffer year by year from irreversible degradation. In practice, this means less output power and less range. When the battery reaches the end of its life, the battery pack – and by extension, the vehicle – is practically worthless. In EVs equipped with a Tanktwo battery pack, this never happens. By swapping deteriorated cells, you can maintain the value and properties of your battery pack to the level you choose. With Tanktwo battery packs you can drive year after year with a brand new battery if you want to. Then again, if your typical driving habit is short distance commuting, you can choose to drive with economy units that are still perfectly good for that purpose, but less expensive to acquire and use.

Is Tanktwo just another battery swapping method?

Cell swapping differs from traditional battery pack swapping technologies in that only the cells are swapped. Cell swapping is one, and maybe the most notable, property of the Tanktwo string battery system. While the possibility to swap the cells for new, fully charged ones is important, other properties of the system might be even more beneficial. Compared to traditional monolithic batteries, the benefits include:

  • More power out of the same battery capacity
  • More kWh out of the same nominal capacity, without compromising battery wear and aging
  • Possibility to carry/own only the needed battery capacity. The great majority of vehicle use cases is short-distance commuting, which can be done easily with only 50% of typical range/battery capacity. This, in itself, already saves more than 200 kg/500 lbs of the vehicle’s gross weight. This is equivalent to the weight of 3 additional adults on board. The decrease in weight saves a substantial amount of money and extends the range per capacity
  • Less expensive vehicles can be sold with much smaller battery capacities. The extra capacity for longer trips can be leased / purchased as needed and returned when no longer needed.
  • The obvious benefits of extending range by swapping battery cells at service stations offers a familiarity to the refueling process we are used to with gasoline propelled vehicles.
  • No worries about an aging battery, or malfunctioning single cells. The cells can be easily swapped any time for a new one and malfunctioning single cells will be replaced automatically. This in no way affects the system function because of the complete redundancy of the system. Users can be completely unaware of the process, even if 10% of cells are not working at all.
  • Being future proof for new battery chemistries – Most of the changes in battery unit design can be covered with a software update, or even without it.
  • Possibility to take cells easily into use for other applications e.g. when cells are not good enough for car usage when capacity has dropped, cells can be used for stationary energy storage.
What happens when new and old Tank Two String Cells get mixed up?

This is a big problem for traditional battery packs because the cells are connected in a series, so each battery is basically only as strong as its weakest cell. In the Tanktwo String Cell Battery, the string cells can be combined in almost any configuration. When the string battery builds its circuits, it combines the string cells into groups based on their properties, keeping the strong cells and weak cells in their own groups. By doing this, any cell can always give its best possible output, and the strong cells are not limited by the weaker ones. This is the main reason why you can get more power and energy out of the Tanktwo string battery, compared to traditional a pack that has exactly the same nominal capacity.