Tanktwo is a Finnish-American battery startup dedicated to improving EV battery performance. Rather than follow the traditional path, Tanktwo searches for innovative solutions in seemingly unrelated industries, drawing inspiration from mobile networks, internet routing protocols, and consumer electronics.
Tanktwo makes components for integration in consumer products. Functional prototypes have been designed and implemented for evaluation by potential customers. In the meantime, R&D for next generation products with higher power density is ongoing as well. Investment rounds are periodically opened to scale up operations and work with additional customers in parallel.
As with all creative innovations, accepting unorthodox solutions requires changes in people’s expectations and mindsets. Tanktwo solutions are based on existent technologies, requiring no revolutionary battery chemistry in order to be implemented in everyday consumer vehicles. We are currently faced with the challenge of helping fixed mindsets accept new solutions to traditional problems, however, we are confident that an efficient, electrified future is within reach, and that Tanktwo technology will be the necessary bridge between now and then.
Sometimes it helps to have a fresh perspective. Tanktwo’s team is full of backgrounds in telecommunications and other non-battery industries: once you redefine traditional car components from the lens of other tech fields, a new world of possibilities opens up.
There are many ways that short distance commuters can benefit from Tanktwo batteries. Since tank capacity can be adjusted towards individual driving needs, weight and cost of unused battery capacity is eliminated during travel. Flexible battery capacity also allows for complete freedom over vehicle mileage and accessibility, which can also be altered as frequently as necessary according to driving preferences.
Typically when a battery malfunctions it is due to one or a few individual cells. In traditional battery packs it is difficult, sometimes even impossible, to identify, isolate, and remove problematic cells. In almost all cases the only option is to change the entire battery, which is an extremely expensive process. With Tanktwo string cells, identifying and replacing cells is fast, easy, and quick, leading to a longer battery life and higher vehicle utilization rate.
Tanktwo string batteries actually improve vehicle performance in comparison to traditional EV batteries. Since drivers can adjust their tanks to the exact amount of cells that are necessary for their commutes, string cells decrease car weight by several hundred kilograms in comparison to cars with traditional battery packs. This results in higher performance and increased battery efficiency within electric vehicles. Also, since string batteries utilize their cells in the order that provides the highest power output, even reduced amounts of string cells can be used in combinations that create an efficient string battery at least as powerful as the traditional EV battery.
Not quite. Current EVs use batteries that are equivalent to the volume of 2000 to 8000 string cells, allowing for a range of 150 km to 500 km. The volume-capacity ratio of a Tanktwo vehicle is actually better or equal to that of current EVs, despite the fact that minimizing weight is much harder than minimizing volume in the design of a vehicle.
While personal cars are the most commonly advertised electric vehicles today, the Tanktwo solution is not limited solely to cars. String cells can be utilized in vehicles of all sizes to increase utilization and mechanical efficiency. In general, Tanktwo batteries can be used for almost all situations involving batteries for energy storage.
Each string battery of a Tanktwo vehicle contains multiple string cells that in turn contain an electrochemical cell. The electrochemical cell inside a string cell is polar. In turn, each string cell’s internal processing unit connects the positive or negative terminals of their internal cells 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. As the string cells are randomly distributed into a string tank, an algorithm determines the best path of energy through the multiple contact points that exist between string cells.
The time for a full cell swap is under 3 minutes at a Cell Swap Station.
Tanktwo battery technology is different because it does not rely on the creation of any new or uninvented ideas; it only requires engineering to be perfected.
Currently, the majority of battery swapping concepts have been tackling the logistics of the actual swapping. Even with working prototypes, many of these concepts are just not technically feasible, nor do they provide any economic benefit. Often, the problem is the inflexibility of the one-battery-must-fit-all approach. With Tanktwo technology, individual cell swapping, or the method of replacing electrochemical cells inside the battery enclosure, allows for rapid cell turnover and fast charges for electric vehicles.
Currently, the shape of an individual string cell is ellipsoid with a special semi-axis ratio. This configuration offers special properties, including the best known possible random fill ratio and the optimal number of contacts between individual units. This ensures that even if string cells are poured into a container, they will always fill the space in the best possible way, making it very hard for them to shift in relation to each other. Compared to a sphere, the ellipsoids fill the container better while still moving with the same ease as spheres.
Currently, battery units are based on lithium-ion chemistry, though any chemistry can be easily implemented within the system. While not optimal, one could even fill a Tanktwo string tank with a mix of string cells utilizing different battery chemistries.
Tanktwo string cells can be built in varying sizes. Typical vehicle packs contain anywhere between 1,000 and 10,000 string cells, though pack size is flexible and dependent on individual driving needs.
String cells inside a Tanktwo string tank form many serially connected individual battery circuits with variable amounts of cells within them. The voltage of these circuits could vary between 50 V to 150 V. These voltages are then converted to a level that is desirable for a vehicle’s power electronics. In short, output voltage typically ranges between 100 – 600V.
Tanktwo batteries have a multifaceted approach towards maintaining sustainable technology. Since string cells reduce battery weight and increase battery efficiency, all Tanktwo vehicles have decreased emissions in comparison to present day vehicles. Additionally, string cells do not need to be retired after capacity has dropped below a certain level, leading to longer battery lifespan and maximized cell utilization. The components and materials used in Tanktwo technology are also designed to be fully recyclable; to be more specific, string cells are designed to be recycled automatically when their performance falls beneath a predetermined threshold. Cell swap technology enables automatic analysis of the state of every string cell. Only when a string cell is absolutely depleted and not usable for storing electricity, whether in an EV or stationary energy storage, will the cell be recycled.
A single string cell contains only a minute amount of lithium, rendering it very safe. In the case of a malfunction, string cells disconnect the internal cell from outside contacts. This makes it impossible for cells to short circuit or otherwise load the internal cell. Additionally, Tanktwo technology includes a detector configured to detect hazardous conditions within cells as well as a release system to eject cells. Since there are no fixed connections between cells, cells are mechanically separated from one another after ejection, preventing the possibility of electrical fires.
Deactivated string cells can be handled like any bulk material; they can be scooped or poured from container to container, and pose no risk of igniting by themselves.
Battery units within the Tanktwo battery pack are secured tightly and cannot be moved easily. Nevertheless, if some battery units were to shift enough to disconnect from the others, the majority of redundant power strings would continue producing power. Even if all battery units were to lose their connections, it would only take a few seconds to rebuild the battery circuitry. During the rebuild, the buffer capacitor in the system would continue to deliver power.
Demo units are currently undergoing evaluation in our offices and with select industry customers. As of today, Tanktwo technologies are in the development stage, and are not yet available for end-user purchase.
By 2018, there will be a number of pilot systems for day-to-day testing. We will announce when these systems are made available for end-user testing.
This is a question that touches on the economics of the string battery ecosystem. When purchasing a new vehicle, costumers will have the opportunity to purchase string cells directly from their car dealer. In this case, the ownership of the string cells is theirs. If this consumer were to drive to a service station and exchange the string cells they own, the ownership is exchanged as well. The value of the exchanged string cells will be calculated during the exchange, as well as the value of the string cells that are received. The owner will be charged the price difference of the string cells, and will obtain ownership of the new string cells that were just purchased. The original string cells become the property of the service station, and will be distributed to other users after they are sorted and recharged in the service station. If the string cells handed in are more valuable than the string cells received, the consumer will receive a financial credit.
To make longer trips, a Tanktwo user can fill their tank to full capacity, even if they originally purchased only half a tank of string cells to support their daily commute. To buy the full tank, the consumer can buy them and then receive the exchange value after reverting to a lower number of string cells. In essence, increasing battery capacity for a weekend is analogous to renting a car.
The service station for filling up or exchanging string cells does not need to be the same. Consumers can alter the capacity of their battery at any time according to their needs.
The price of Tanktwo battery capacity always 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.
Average EV’s can be sold from a factory equipped with string cells for 150 km of range, covering 95% of typical use, then upgraded on demand to up to 500 km when needed. This ensures both a low price and flexible car range. The result is an EV with a capacity for a 500 km range, that can be packed with 150 km worth of cells for daily commutes, creating an exceptional cost advantage.
Tanktwo battery cost per kilowatt hour is actually less than that of a traditional battery pack. It is true that each Tanktwo battery unit contains sophisticated electronics, but all the technology is fitted into a single integrated circuit chip even smaller than a finger nail. In contrast, traditional battery packs require huge amounts of mechanical parts to be secured within the larger vehicle. Often, thousands of individual cells are required to form the necessary battery circuit. By comparison, Tanktwo battery packs are simple containers in which the individual string cells form a random circuit network, from which almost any kind of cell circuitry combination can be formed.
Tanktwo String Batteries do not require any new infrastructure to be beneficial beyond the normal maintenance tools at authorized OEM maintenance centers. The number of stations required for swapping and charging cells are fewer than gasoline stations, since Tanktwo batteries are usually charged just like any plug-in EV.
A vehicle with a Tanktwo battery system can be charged just like any plug-in EV. Swapping cells at a service station is a faster alternative for charging the battery, and can be utilized as a super-quick charge option; a full cell swap can recharge the vehicle in less than 3 minutes. Cell swapping also allows for large economic benefits, as batteries can be charged at cell swap stations when the cost of energy is at its lowest, for example during the night.
Consumers have the option to choose battery quality at large stations, similar to the way one can choose the octane grade in present day gasoline stations. When emptying or refilling their string battery, consumers will be compensated or charged depending on their battery transactions. Service stations and each individual string cells know the current value of each cell, a value based on battery type, age, use history, and charge status, amongst other factors. After a swap, consumers pay the difference in values of swapped string cells; in this way no party is ever disadvantaged by a string battery transaction.
EV’s equipped with traditional batteries suffer from irreversible degradation. In practice, this means decreased output power and range. When a traditional battery reaches the end of its life, the battery pack is practically worthless; by extension, as is the vehicle. In EV’s equipped with a Tanktwo battery, the vehicle doesn’t lose value because of its battery. By swapping deteriorated cells, consumers maintain the value and properties of their battery pack at the level they choose. Tanktwo technology allows consumers the ability to drive year after year with an inexpensive, brand new battery.
Cell swapping differs from previous battery pack swapping technologies in that only the individual cells are swapped, though cell swapping is only one property of the greater Tanktwo string battery system. Compared to traditional monolithic batteries, the benefits of the Tanktwo system include:
Though this poses a problem for traditional battery packs due to the cells being connected in a series, leading to a battery only as strong as its weakest cell, Tanktwo string cells can be combined into almost any configuration. When the string battery builds its circuits, it combines the string cells into groups based on their properties, keeping strong cells and weak cells within their own groups. By doing this, any cell can always give its best possible output, and strong cells are not limited by the weaker ones. Even when old and new cells are mixed, consumers get more power and energy out of the Tanktwo battery compared to traditional packs with the exact same nominal capacity.