Just when it seemed that the battle of the EV battery was over, and that China had won, a little-known American tech company said: “Hold on, not so fast. We actually have a game changer, a new kind of battery that is better at all the parameters EV batteries are now ranked”. This battery will give an EV 50 percent more range than any comparable battery, cost less to produce, reduce the risk of fires, can be made in almost any shape, and can be mass-produced in the factory that makes EVs.
This revolutionary battery is called ETOP (electrode-to-pack), and it is made by 24M Technologies, a Cambridge, Massachusetts-based company. 24M’s battery technology has attracted attention and investments by the likes of Volkswagen since the early 2020s, and the ETOP battery is the culmination of several of the company’s tech breakthroughs used together.
How The ETOP Battery Compares To A Traditional Pack
The electrode-to-pack system creates a sealed anode/cathode pair that is integrated directly into the battery pack. This eliminates the need for individual cells, modules, and heavy non-energy-carrying materials. It achieves the highest energy density because a higher percentage of the battery is made up of electrodes and other materials, the energy-carrying components.
ETOPs Versus Traditional Battery Packs
Traditional battery packs look like cans of soda in a box. Each cell is wrapped and protected by a metal casing, and these are grouped into modules, which are fixed into a pack. Because each cell has a round diameter, there is a lot of wasted space in each module, while the individual cell’s metal wrap is quite heavy and carries no energy.
While each EV cell on its own is quite small, the number needed in a current EV is mind-boggling. The Tesla Model S with the 100 kWh pack uses 8,256 cells, for example. This way of packing energy uses a lot of dead space, which means the electrodes make up between 30 and 60 percent of the battery’s volume.
What Manufacturing ETOP Entails
An EV battery is made of an anode (negative electrode — normally graphite), a cathode (positive electrode — a metal oxide), and a separator between them, with an electrolyte solution that allows movement between these electrodes. Unlike normal EV cells, the ETOP looks like layers of fabric laid atop each other, the two electrodes, and the separator. These are mounted on a sheet of polymer that can be cut to size or shape needed, and encased in plastic. This electrode-to-pack allows for 80 percent of the pack’s volume to be active energy material, unlike the maximum 60 percent achievable with standard cells. These packs can then be layered on top of each other, either in series or in parallel, in a very compact pack.
The Benefits Of Using An ETOP Battery
Besides the benefits of higher energy density, the nature of ETOP also means the EV can travel up to 50 percent further per volume of battery space used. The battery storage area can be further optimized because an ETOP pack does not have to be square or rectangular like normal battery packs, but can be cut to fit around curves or structural angles in the chassis of the car.
Fire Hazards Are A Real EV Concern
One of the risks of EV batteries is fire, although the risk is getting less over time. But as battery makers are seeking greater efficiency, the overlap in the layer of anode and cathode is reduced, which does increase the risk of fire if the battery is damaged during an accident or by the formation of dendrites over time.
ETOP uses a semi-solid electrolyte, which is easier to manufacture than the solid-state batteries we may see in the near future. Unlike the liquid electrolytes used in all other EV batteries, the semi-solid electrolyte is also far less flammable. These semi-solid batteries will also last longer through repeated charge/discharge cycles, which means the battery will degrade less as the vehicle gets older. Because they are not really affected by heat, they are better able to withstand really fast charging.
The ETOP Combats Dendrite Formation
Dendrites are metal structures, shaped like tiny trees, that grow on the anode during charging. These can eventually pierce the battery’s separator, causing reduced battery performance, and can lead to overheating, failure of the battery, fire, or explosions. The separator in the ETOP is made of another material patented by 24M Technologies, which blocks the dendrites and causes them to spread horizontally, where they will eventually be reabsorbed by the materials in the separator.
Flexible Power Opens The Door To Endless Possibilities
Another way of making a battery cell is rolling up the electrodes and flattening them in a container. Such a can cell will reach 4.6V. If 11 ETOP cells are stacked on top of each other, with each cell flipped alternately, each can will provide 48V by wiring them in series. Because these cells can be flipped, series and parallel connections can be made. This gives flexibility, allowing compact 400 to 800V batteries.
Chemistry Agnostic Increases Production Viability
Lithium-ion batteries are well known in EVs, but battery makers rely on several different chemistries to achieve different outcomes. Some are cheaper, but offer less energy density, while others are more efficient, but the materials used can be expensive and come with the baggage of dubious mining sources. The main battery chemistries are:
- Lithium Nickel Manganese Cobalt offers high energy density, but high cost and ethical concerns in mining methods.
- Lithium Iron Phosphate with low cost, long life, but low energy density and greater weight.
- Lithium Nickel Cobalt Aluminum Oxide gives high energy and a long lifespan, but high cost and ethical considerations.
- Sodium-ion batteries are cheap, but not yet fully developed, and currently lack density.
ETOP batteries are agnostic in the chemistry they can use, with the cathode using any of the chemistries described above.
Numerous Manufacturing Advantages
Carmakers can integrate an ETOP manufacturing module into their pack assembly line. To make a battery cell, the manufacturer cuts the prefabricated anode and cathode material into the desired size and shape, using the chemistry of their choice. Both electrodes have a plastic backing, which will be used to seal the cell once the two electrodes have been sandwiched together.
After being cut to size, each layer is sprayed with a semi-solid electrolyte, and a separator is rolled onto the anode. The cathode, which has also been sprayed with the electrolyte, is placed on top, forming the electrode sandwich. The plastic films backing the anode and cathode are sealed together, locking the separator in place.
Production Happens On A Single Machine
All these steps happen on a single machine. The sealed electrodes are then inserted into a pack, where the packs can go directly onto the assembly line. This gives manufacturers a way to build compact, high-voltage batteries at a low cost, and it is a way that can be integrated into the manufacturing process.
If ETOP works as advertised, it can jumpstart US EV battery manufacturing and allow it to compete directly with the dominant Chinese. There is, however, a gap between promise and successful application, and the EV battery industry in the rest of the world has progressed in great leaps.
The EV Battery Picture In 2025
The 800-pound gorilla in the room is the Chinese EV battery industry. China’s car market is double the size of the US, and EVs make up about half of sales in that country. The success of Chinese EVs is based on their dominance of the EV battery market, where CATL and BYD are absolute market leaders.
This dominance has been decades in the making, with massive government support, scale of production, ownership of all facets of the supply chain, and the ability to develop new EVs in record time. Chinese firms BYD and CATL have recognized the value of LFP technology and have found innovative ways to overcome the drawbacks of this chemistry.
All is not well in the Chinese EV space, however. There are over 200 EV companies, with as many failing as starting up all the time. There is a massive price war among manufacturers, which has cut the profits of even the major players. Globally, Chinese EVs are seen as superb value for money, but also as a threat to local car industries, and are subject to tariffs. But the Chinese advantage is undeniable, and even Ford is using CATL technology under licence in its new US battery plants.
Solid State Science Is Advancing
Solid-state batteries have been the nirvana of EVs for over ten years. This difficult technology is finally coming to fruition, with both Toyota and Nissan on the verge of mass production, although the future of Nissan at the moment is bleak. A Merc EQS with an experimental solid-state battery recently drove 748 miles on a single charge, with some miles left in the battery. The range of non-solid state batteries is also increasing rapidly, with the number of models breaking the 500-mile barrier increasing all the time.
Traditional Battery Costs Plummeting
The major obstacle to the adoption of new technology like ETOP is that the cost of proven battery technology is plummeting. Battery prices have dropped by over 90 percent in the past 15 years, and the 2023 price is expected to drop by 50 percent by 2026. At $80 per kWh, this will soon drop below the cost of making a gas car, which will mean the end of gas cars. The problem 24M Technologies faces is not that it does not have a very good product, but rather that the risk of moving to such technology will be greater than the reward in a world where batteries are getting cheaper and better anyway.
Sources: 24M