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24M Electrode-to-Pack Technnology

1 November, 2023

24M Electrode-to-Pack Technnology

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Can we change the way we build EV batteries? 24M presents their Electrode-to-Pack Technnology that looks very promising indeed.

One of the most important aspects of any electric vehicle battery is what’s called its “power density“. In simple words, the power density of a battery measures how much “juice” a specific battery can produce within a specific volume. For example, let’s say we have two identically sized batteries to compare: the first one is sized 10cm x 10cm x 10cm and produces 50W/L (watts per litre), and the second one has the exact same dimensions but produces 66W/L. Obviously the second one is better, as it packs more energy in the same size (volume) as the first. Or, if we see it from the perspective of a vehicle manufacturer, they would need fewer batteries of the second type to achieve a specific range.

Why is power density important?

In today’s extremely competitive world of electric vehicles, manufacturers compete to create vehicles with as much range as possible. There are several ways to achieve that, namely:

  • minimise the vehicle’s overall weight by using lighter materials
  • make the batteries weigh less
  • use more efficient battery chemistries and materials so that the batteries produce more energy for the same volume/size
  • optimise the aerodynamics of the vehicles to reduce drag

The more manufacturers improve any of the aspects above, the better the range of their vehicles is. And vehicles with longer range, sell more.

In the ever improving and constantly changing world of batteries, there has been one process that hasn’t evolved much, and that is the way batteries are built. Until now.

How are EV batteries built?

Batteries are built using what’s called the Cell-to-Module-to-Pack assembly. There is an anode and a cathode for every cell. These are connected to another cell’s anode and cathode and so on. Once we have enough (the number varies per case), we join them together to create a Module. Then we join Modules together to create Packs. Several Packs are then put together to create the vehicle’s battery. The schematic below shows a simplified schematic of how this works.

Battery Cell to Module to Pack

Battery Cell to Module to Pack

The vast majority of EVs in circulation today are equipped with batteries built exactly like that. If we were to open a battery from such a vehicle, we could break it down to small cells (after quite some dismantling), similar to those used in torches or e-cigarettes.

In their efforts to produce the smallest and most powerful batteries they can, it is normal for battery manufacturers to invest huge sums of money in research. Until now, the constant of the Cell-to-Module-to-Pack assembly was kept the same, with experimentation concentrating on different anode and cathode materials and different electrolytes. But a company called 24M Technologies announced at the 2023 Japan Mobility Show in 24 October 2023 the introduction of a transformative new battery technology called the 24M Electrode-to-Pack system that will change everything in the way modern batteries are built.

What is the 24M Electrode-to-Pack system and why is it an exciting announcement?

We mentioned earlier that EV batteries consist of cells, assembled in modules, which are then assembled to packs. Within these batteries, there is a large amount of plastic and metal parts and assembly materials that do not offer anything in terms of energy, with their only purpose being keeping the structure of a battery together. Nevertheless, this dead weight is necessary as it wouldn’t be possible to just throw the cells in a bag and call it a day. Understandably, all these materials take precious space, which in turn makes the power density of the battery drop. To put simply, a large percentage of the battery’s volume and weight is not there to provide energy, but rather to contain and structurally sustain the parts that do.

24M’s solution gets rid of most of this dead weight and space that is not producing any energy. Instead of having separate cells (and their accompanying anodes, cathodes, packing equipment and so on), 24M replaced the separate small cells with one big cell, and then integrated the anode and cathode into it. The result is a battery that comes with several advantages over the conventional design that has been used until now:

  • Electrode efficiency of over 70%. This is the highest pack-level volume utilization efficiency available right now.
  • Lower cost per pack. As unit electrodes can be connected in a combination of series and parallel, there is no need for additional connection components and packing/assembly materials, so the cost is less.
  • Longer range and battery cycle life. Higher power density allows for more juice in each battery, so for the same volume we get longer driving range.
  • Safety benefits. 24M claim that their system offers unmatched safety when subjected to mechanical abuse.
  • Flexibility. As the 24M Unit Cell can be connected in series, parallel or in a combination of series and parallel directly within a pack, limitations of individual cell voltage and capacity no longer apply. This means that the types of vehicles the cell can be used in are now more varied than with normal batteries.

In the main article photo, you can see the cathode (grey colour) and the cell inside it (darker red in the centre of the graphic).