Graphene or not? Investigating the Panasonic NCR 21700 powering ...

Graphene or not? Investigating the Panasonic NCR powering the Tesla Model 3 and Chargeasap Power bank

Panasonic is one of the top five Li-ion battery manufacturers worldwide [1]. In partnership with Tesla, they built the Gigafactory facilities in Nevada [2]and designed the NCR batteries for the Model 3 electric vehicle (EV). This cell benefits from a 5% improvement in energy density and by increasing nickel content in the cathodic material, namely (NCA: Lithium Nickel-Cobalt-Aluminum Oxide (LiNixCoyAlzO2)) and introducing silicon in the anode [3].

Panasonic NCR and the Tesla model 3:

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The NCR battery was designed to improve the power and energy densities beyond what is available with the Panasonic PAN BD cells [4]. Although NCA cells theoretically provide similar energy density and power density to Lithium-Nickel-Manganese-Cobalt-Oxide (NMC) based cells, their fast charging is more challenging due to the oxide layer formation at the cathode during discharge, increasing the battery's impedance. To overcome this issue, Tesla designed a heating management system to warm up the cells to a specific temperature before fast charging. This method can reduce the charging time to ~ 80 minutes without compromising the cyclic life of the battery.

Panasonic NCR and the Chargeasap FLA201G 210 W Power bank:

Chargeasap is a Sidney, Australia-based startup that aims to create innovative charging accessories for mobile devices. They typically launch their products through a crowdfunding process. Interestingly, the Chargeasap FLA201G power bank uses four Panasonic NCR batteries. Chargeasap claims that these NCR cells benefit from graphene technology leading to a full charge in just 70 minutes (20,000 mAh) or 80% charge (16,000 mAh) in only 35 minutes. The controversial aspect of Chargeasap’s claims is Tesla never mentions the application of graphene in any of their NCR descriptions. With the amount of interest in Tesla and the NCR cell, TechInsights wanted to get to the bottom of this mystery and understand the underlying technology of this battery.

Reverse Engineering the FLA201G Power Bank

We opened the Chargeasap FLA201G power bank and found that the battery pack consists of four Panasonic NCR in series (4S). Figure 1 shows the inside of the device along with its batteries.

Figure 1: Inside the FLA201G power bank.

Battery Cells

The cells are cylindrical shaped (70.5 mm long and 21.1 mm in diameter) with a capacity of mAh with an average cell voltage of 3.7 V

Figure 2 shows an individual cell used in the FLA201G 210 W Power bank.

Figure 2: Individual cylindrical cells used in a FLA201G power bank.

Battery Materials

Different components of the battery were characterized using various methods, including Scanning Electron Microscopy (SEM) coupled with Energy-dispersive X-ray spectroscopy (EDX) at different locations and magnification, FTIR (Fourier transform infrared), and Raman spectroscopy. Looking deeper into the cell structure (Figure 3) we see the cell jellyroll is comprised of ~165 µm thick layers, including the aluminum current collector, the cathodic material, the polymeric separator, the anodic material, and the copper current collector [6].

As expected, the cathodic active material is Lithium Nickel-Cobalt-Aluminum Oxide, as confirmed by our Energy-dispersive X-ray spectroscopy (EDX) test's results. The anode is formed with graphite containing embedded silicon oxide (SiOx or SiO) particles. Incorporating SiO increases the battery's capacity by forming lithium silicides, which can bind four lithium ions for every silicon atom. Theoretically, "Silicon anodes can store ten times as much charge in a given volume than graphite anodes -- a whole order of magnitude higher in energy density" [5].

Figure 3: Detailed SEM Cross Section of the jellyroll.

Presence of graphene in the anode active materials

The presence of graphene is evaluated by Raman spectroscopy by taking samples from 3 different parts of the anode jellyroll (beginning, middle and endpoint), and the results are plotted in Figure 4. Analyzing the spectra reveals that no graphene is used in the anode of this battery as an additive, and the Raman spectrum is well-matched with ball-milled graphite. Now, a question arises why Chargeasap claimed the presence of graphene in this battery. This could be attributed to the fact that Ball-milled graphite features a similar Raman spectrum to that of graphene nanoplatelets. To better understand this statement, we need to get insight into the Raman spectroscopy of graphite and graphene. Raman spectra of graphene include three main bands, namely, Figure 4, the G-band, the D-band, and the 2D-band. These bands are indicative of the number of layers of graphene present and the quality of the sample. G-band and 2D-band will always be present. However, the D-band will only be seen for samples containing defects for both graphene and graphite. The 2D band provides conclusive information regarding the presence of graphene [7,8].

Figure 4: Raman Spectroscopy of the anode of Panasonic NCR .

In the case of pure graphene, the 2D band situated at ~ cm−1 is a sharp and symmetrical peak. Whilst in the Raman spectrum of graphite, the 2D band is formed from two elements leading to an asymmetric peak. This peak evolution is due to the fact that graphite is a multi-stacked layer of graphene. As the number of graphene layers increases to about ten layers, the profile resembles that of graphite [7,8]. Additionally, in the case of pure graphene, the intensity of the 2D band would be higher than that of the G band.

Figure 4 shows that the 2D band slightly deviates from a symmetrical shape indicating a stacked layer of graphene (almost 5 layers). However, the intensity of the 2D band is significantly lower than G-band. In the case of pure graphene, the intensity of the 2D band would be higher than that of the G band.

The existence of the D-band suggests some defects in the particles, indicating the process of ball-milling during battery manufacturing. Ball-milled graphite or ‘nano graphite’ consists of spherical particles containing highly defective crystalline structure as a direct consequence of ball milling. These structures have been named graphene nanoplatelets or multi-layer graphene in literature. However, a long process of ball-milling (24 hr.) leads to a significant exfoliation of graphene nanoplatelets from the graphite. In the case of NCR , the ball-milling process is estimated to be around 12 hr., leading to a marginal exfoliation of the graphite and the formation of graphene nanoplatelets (GNP) [9]. Therefore, the existence of a fraction of GNPs should not be mistaken by the application of graphene (like reduced graphene oxide) as an additive in the anode of lithium-ion batteries.

To see a practical example of a significant amount of graphene added to the anode to substantially improve the power density of a Li-ion battery, please refer to our recent report entitled “LPR Graphene-4 graphene-enhanced anode LiPo (RC car pack)” in our Battery Essentials channel [10].

For additional information on the Panasonic NCR cell including active materials (NCA and Graphite), the existence of dopant particles, separators, and electrolyte components, please see the full report entitled “Panasonic NCR LIB (Chargeasap)” [6].

References

The cell is one of the most popular types of rechargeable lithium-ion batteries, and for good reason. They are readily available and reasonably priced. The lithium batteries are a more recent invention that has some clear advantages over the , but it also comes with an increased price tag.

However, they both do have their advantages and drawbacks, vs battery. Which type of battery should you buy? Keep reading to learn about the differences between these two types!

Common similarities between and battery

There are several key similarities between a and battery that makes them both great options for LEV (light electric vehicle) and other applications.

Firstly, both lithium-ion batteries have a high discharge rate, meaning that they can provide the high levels of power required by LEVs.

Secondly, both the battery pack and the battery pack come with the same voltage, which is 3.7 volts. This is the standard voltage for LEV batteries, and it ensures that there are no compatibility issues between different types.

Thirdly, they can be used in a wide range of temperatures, making them suitable for use in a variety of climates.

Fourthly, and cells are cylindrical.

Finally, both types have a long lifespan, meaning that they will not need to be replaced as often as other types of batteries.

If you are more interested in cells then you should know how to choose the best battery for LEV.

And if you are more interested in cells then you should know how to choose the best battery for LEV.

Major differences between vs battery

There are many differences between and batteries. Some of these differences include:

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Power output

When choosing which type of lithium-ion battery to buy for your device, you should consider how much power output you need. If you know that the application will require a lot of energy and you don’t want something too bulky or heavy, then it would be best to go with cells over .

Battery cell weight

batteries weigh around 60g, compared to around 48g for . But their weight can vary depending on specifications.

Price

You should consider the price difference between the two types- s tend to be more expensive than batteries. This is because the battery is newer and has more features than the .

Energy Density

batteries have a higher energy density than .

The capacity

The is one of the most popular types of rechargeable lithium-ion batteries, has a capacity of -mAH while the has a higher capacity can reach up to mAH, which means cylindrical li-ion cells have more energy density, which can result in more runtime.

Damage

Additionally, batteries are more susceptible to damage from external factors such as heat and pressure.

Dimension

batteries measure 65mm in length and 18 mm in diameter while batteries are 70mm long and 21mm wide. The dimensions of the two types vary greatly, with one being significantly longer than the other. This is because of their different capacities—the larger capacity of the lithium-ion allows it to be larger in size and have high power.

Are batteries better than ？

batteries are newer and larger than . They offer more capacity and discharge at higher currents. batteries also have a longer cycle life. However, they are more expensive and may not fit in all devices that use batteries.

So, what’s the verdict? If you need the extra capacity and discharge current, go with a battery. If you’re looking to save some money or your device only takes batteries, stick with the .

Can you charge batteries in a charger?

The quick answer is yes, you can charge batteries in a charger. However, we recommend using a dedicated charger whenever possible for the best results.

Does last longer than ?

The simple answer is yes, batteries typically last longer than batteries. One of the main reasons that the lithium-ion battery is less powerful than the is that they have a lower capacity and energy densities are lower.

This means that they can’t store as much energy as lithium-ion, which can result in less runtime.

It is important to note that the longevity of a battery depends on a variety of factors, including the frequency of usage, storage, and type of device that use it. So, while batteries may typically last longer than batteries, there are no guarantees.

Do vs battery have different applications?

vs battery for application to maximize efficiency, cost-effectiveness, or power output.

You would want something that can last longer, weigh less based on the same energy content, have more weight efficiency, and give you more power to get the job done right.

In this case, you need something that works well with high power output, which is why the cells are probably your best bet.

How does the size of lithium-ion batteries affect their performance in an application that requires them to be lightweight and compact?

The size of a lithium-ion battery can be important in applications that require them to be lightweight and compact. For example, if you are using a battery in a drone, the less weight the better.

In this case, a battery would be a better choice because it is lighter in weight and has more weight efficiency.

Application of lithium-ion batteries

Application of batteries on electronic devices

How to choose the correct lithium battery for your project?

Tritek, as a professional lithium-ion batteries manufacturer, can provide different battery packs to install in various drive systems, such as LEVs, robots, marines, agricultural , etc. We usually sort battery packs based on their voltages.

FAQ

1. What are the different types of lithium-ion cells used in and batteries?

Lithium-ion batteries, including both and cells, can be made using different chemistries, such as lithium manganese oxide (LMO), lithium iron phosphate (LFP), and lithium cobalt oxide (LCO).

2. How does the nominal capacity differ between and lithium cells?

The nominal capacity of lithium cells varies between and batteries. Typically, cells have a capacity range of -mAh, whereas cells offer a higher capacity, often reaching up to mAh.

3. Can other battery types offer more room for energy storage compared to lithium-ion cells?

While lithium-ion cells, such as and , are renowned for their high energy density and efficiency, other battery types like solid-state batteries and lithium-sulfur batteries are being developed to offer even more room for energy storage. However, these alternatives are still in experimental stages and not as widely available or proven as lithium-ion cells for practical use in applications such as LEVs and consumer electronics.

How much do you know about Li-ion battery cells? Here is a comprehensive explanation from Tirtek’s R&D Director. ↓↓↓

If you are looking for more details, kindly visit Cells for Electric Drive Systems.