Auf den Spuren eines E-Bikes – Das Akkusystem I Episode 2 (DSV x TQ)

Hello and welcome here at TQ. Today we're going to swap skis for bikes and take a look at how such an e-bike system is set up. So, I'll see how the electricity gets into the bike and I was told I can go to the workshop and ask about Dani there. Hello – are you Dani? Yes, exactly. Well, then I'm right. You work here in the workshop for the batteries, right? I'm the product manager at TQ for the e-bike sector and e-bikes are practically my baby. And yes, I have prepared a little something here and then I can show you a little bit about the batteries and how we make the difference, how our batteries differ from the others and a little bit in general what is actually in such a battery , I would show you that today. Yes cool. It looks like a normal now, what role do the other four have? Exactly, I've prepared a little something. Ultimately, when you hold an e-bike battery in your hand, you only see the housing. Unfortunately, you can't look inside. That's why we opened one here and I 've prepared a few cells here so that I can explain the differences to you a little bit .

You have already correctly recognized that this is a normal AA battery in this case. So it is not rechargeable. And here I have just prepared a few commercially available cells . They all have beautifully different colors and there you can pick out your favorite color. Ultimately, every manufacturer has its own color. But they are of the type, at least these three that are here in the middle, all the same. We call the 18 650s and that ultimately only describes the dimensions of this battery. So if you compare – all three are exactly the same height and have the same diameter, namely a diameter of 18 mm and a height of 65. That is one of the usual dimensions. In addition, there is another measure that has now been added, especially in recent years. This is the 21 700. So again, as the name suggests, 21 mm in diameter and 70 long. So if you compare them, they are just a tad longer and a bit thicker in diameter.

Does it have more steam then, right? Exactly, basically the same thing is inside, but if the cell is larger, then of course there is more capacity, for example. So there is just a little more energy in there, if you will. But these are lithium-ion batteries, or what are they? Yes, exactly, they are all lithium-ion cells. Actually, from a certain price level onwards, only lithium-ion cells are used in the e-bike sector . Depending on what kind of model it is and what kind of manufacturer it is, there are cells that are made more for being really out for power, i.e. they can deliver very high currents and a lot of power in a short time without getting too hot and then there are cells that are more designed for endurance . So they have a higher capacity. That means they can't give that much power at once, but they simply have a higher capacity and, for example, you notice that in the range. So the one cell that is designed a lot for power, so maybe you could use our 120 motor, which is particularly powerful, you could operate it better because it naturally draws a lot from the battery.

With the other cell, which is designed more for capacity, you will notice that you are simply getting a little further. One is no better than the other, you just have to see what the application is and that is the great art of coordinating it exactly so that the battery ultimately fits perfectly with the motor and fits perfectly with how the bike is used target. So if you look in here you can see that there are a lot of cells in there – how many is that roughly? – We always have an arrangement where we say the cells are 14 in a row and 4 in series. That means 14 x 4 = 56 and that's the number of cells in there. The real trick is choosing the right cell for your application and matching the whole thing with the electronics in these batteries to perfection. That's why we at TQ do the electronics ourselves. Because these electronics and software have to communicate perfectly with the motor and the battery has to be perfectly coordinated with the motor so that the two of them know exactly: how is the other one, how much power can I now access, what is the range.

pexels photo 7018256

In the end, you want a battery that is simply perfectly matched to the needs of the customer. So the customer should have maximum driving pleasure and that for as long as possible. The range and all that we can of course determine to a certain extent by the cells, but it is determined even more by how well this system simply communicates with each other and how fine this interlocking is, so to speak, between the various components in the e-bike. Now a stupid question: How much can you save if you program it cleanly and clean the electronics? So one thing is what we can gain in reach.

There is easily 10% range and you can really notice that on a 60-70 kilometer tour and another reason why we always make these electronics ourselves is that we just manage to build the electronics a little more compact than the others. That means we know what everything has to be on it and we can simply put it in a more compact circuit board and thus ultimately waste less space for electronics in the battery housing , so to speak. So the customer should have maximum driving pleasure and that for as long as possible. The range and all that we can of course determine to a certain extent by the cells, but it is determined even more by how well this system simply communicates with each other and how fine this interlocking is, so to speak , between the various components in the e-bike.

May I reach them? Yes. So there you can already see that the cells, in the end these are now these cells, you can see that a bit because the green color shimmers through, they are very, very tightly packed together. If you took a closer look, there are thin cables everywhere in between. These are temperature sensors. That means we monitor the temperature in several places in the battery all the time, because of course we have to be very careful.

The cells only have a certain temperature robustness and we just have to make sure that we always stay within their comfort range when charging and discharging. Yes, stupid question – but may I try it out? That's what we're here for – of course. I would say we take the 120, that's our powerful engine, you can really feel it going on right away and then we just do a lap. Yes, thank you..

You May Also Like