Wednesday, September 16, 2015

The things you don't know about drone's smart lithium battery, Part I

From the business structure, drones lithium battery becomes intelligent, It is a good direction and forms. Conversely, this form of business model also makes more profit potential. In our daily life, smart lithium has been everywhere, laptops, cell phones, and many mobile devices, already adopted the smart lithium battery. UAVs power lithium battery, it is the transition to smart lithium. However, this article, do not speak of this trend,  we talk about drones smart lithium batteries advantages and disadvantages.

Part I: How ordinary batteries become intelligent

Batteries, we are not unfamiliar, no matter what technology, what material manufacture, it is just a power storage medium. Power through the battery terminals to load (electrical equipment) energy exchange (use of electrical equipment to do work). Disposable battery is dead, the device needs to put a new battery; rechargeable battery is dead, fully charged can continue to use. But, when the applications conditions become more complex, this simple form of battery power is no longer so very satisfied with it! How can I make the battery work more satisfied?

1. Solve discharge problem spawned smart battery

For rechargeable batteries, over-discharge is the most annoying thing. Over-discharge means that the battery performance degradation, or even scrapped. To avoid over-discharge, in the battery pack has increased by over-discharge protection circuit, when the discharge voltage drops below a preset voltage, battery-powered outwardly stop. However, the actual situation is even more complicated, such as laptops, unmanned aerial vehicles, electric cars, if for avoiding battery discharge and immediately stop power supply, then the computer will immediately shut down, too late to save a lot of data; unmanned aerial vehicles, will direct fall from the sky; electric car will break down in case without any signs. Thus, intelligent battery discharge cut-off self-protection is only battery last line of defense, before this, the management circuit also calculates the end of life, to provide early warning for the user, so the user has enough time to take appropriate security measures.

For the calculation of life time to deal with them in a small current devices much simpler, for example: The computer notebooks, mobile phones and so on. But for someone like unmanned aerial vehicles, electric cars, etc., such work large current, the current changes, the complex conditions of the system, it requires a dynamic to calculate life, then the situation becomes much more complex.

For example the DJI Phantom 3, the smart lithium battery which uses after data fusion and flight control can achieve three voltage warning protection.

First level: when the remaining 30% power is detected, it will start the alarm, prompting the user should pay attention to the remaining power, return prepared well in advance;

Second level: When detecting the the remaining power enough to maintain return, will be executed automatically return; and this time point with flight distance, height is associated, It is an intelligent battery data with flight control data calculated in real time after the integration.

Third level: When detecting the the remaining power is not enough to maintain a normal return (such as the return voyage encountered headwinds, it is possible to exceed the estimated return time),  will landing in situ, in order to maximize avoid drones crashed due to power shortage cause.

2. Solve the charging and preservation problem spawned smart battery

As we all know, lithium battery charging, there are special requirements. Currently a large number of lithium batteries using a multi-core serial to parallel form, due to the batteries of individual differences, resulting in the charge and discharge can not be 100% balanced, Thus a perfect charge management circuit is particularly necessary. And that is to have a smart lithium second function - perfect lithium battery pack charge management, and discharge management.

For example DJI Phantom 3 battery

One of the functions: The intelligent lithium battery has actually built a dedicated lithium battery charge management circuit, and be able to electric core monomer voltage balance management. Therefore, charger (power adapter) as long as the appropriate charging voltage and charging current, it is possible to charge the smart lithium. Thus phantom 3 charger, is only a power adapter, the real charge management circuit in a battery inside.

Another function, The intelligent lithium battery have self-discharge function. When the battery charge more than 65% for 10 days without any operation, the battery will start self-discharge program, will put 65 percent power in order to save time in the lithium battery. Self-discharge time interval can be set via the App.

3. Solve battery check problem

Conventional battery voltage to be detected, the need for additional connection detection device, such as a voltmeter, etc., but this detection is not in real time during the flight. There is no more convenient and intuitive way to let users know in real time the remaining battery power and other information? Yes, this requires a battery management circuitry to complete.

1.) Detecting the remaining power. By 4 LED lights intuitive prompts the user's current remaining battery power, real-time display, during the flight can be displayed.
2.) Through digital image transmission, real-time voltage data backhaul, and even be able to view the voltage of the battery pack in the monomer in the APP.
3.) Record battery historical data, such as: frequency of use, abnormal times, battery life.
4.) Prompt battery abnormality. LED lights can Prompt by a variety of batteries abnormalities, For example: short circuit, the charging current is too large, high-voltage, high temperature, low temperature and so on.

4. Solve plug aging

When we connect the batteries to the drones, plug sparks, accompanied by the sound of the ignition. Over time, the plug connection reliability is reduced, and will lead to plug fever, and even melted in the air. Plug aging problem caused due to drones crash cases are not uncommon. To solve this problem, the lithium battery intelligent management circuits and also play a role.

When you put the batteries installed on the Phantom 3, and electrode contacts does not really discharge, it will not produce a spark, it will not produce galvanic corrosion phenomenon, this way, the life of the contact point will be able to gain unprecedented promotion. Touch switch by clicking on the button on the battery, batteries will really enter the electricity output state, of course, when you close batteries, but also through touch switch button to execute.

5. Solve the battery copyright (profit)

Smart lithium battery has been well protected by copyright, On the one hand, can only use the factory supplied lithium battery, the battery can get better quality assurance, consistency is also good, in theory, better reliability; On the other hand, our drones, only our lithium batteries can work! Someone also trying to crack the encryption of smart lithium battery, but once the firmware upgrade drones, those data cracked may fail, resulting in a lot of clone battery is not working.

More about about drone's smart lithium battery clic here The things you don't know about drone's smart lithium battery, Part II

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