Finished product display

Imagine:

A big thing happened a while ago, which is a big thing for me. It was the biggest heavy rainstorm I have ever seen in my life. The difference compared with previous summer heavy rains is that due to the influence of typhoons, this rain continued continuously. It has increased to the point that most areas in Henan cannot withstand the flood discharge pressure. In those days, water flooded the entire city. Roads, electricity, internet, and water supplies all suffered extensive damage. The power and water were out for many days. At that moment we realized that the electricity and running water we take for granted are so precious and indispensable! Although I guarantee the power supply for mobile phones and lighting by squeezing a large set of battery packs to obtain power that neighbors cannot get (thanks to the converters and battery packs I bought before). But the thought of being prepared for danger in times of peace has stuck with me, which gave me the idea of ​​getting a large-capacity power bank. Before, I only had a 10,000mAh power bank, many lithium battery packs and the familiar 18650 that didn’t work. Very few power banks sold on the market have enough capacity. Don’t ask me why I’m impressed. There are only three 18650 cells in a 10,000mAh power bank. The power of this manufacturer’s battery can seize the market share of Toshiba and Panasonic, which is living a good life. .

Moreover, the fast charging module I modified to give me a power bank to a certain extent (without a casing and like a cluster xx) was asked by my friends whether it was a power bank made by myself. I didn’t know how to answer it appropriately because they couldn’t tell the difference. The difference between using ready-made modules and using your own drawing board . Now I want to make a 30000mAh large -capacity power bank , a fast charging solution based on IP5358 chip.

shell

In order for others not to be afraid of it, it needs a sturdy shell and good heat dissipation. A large number of battery cars drowned due to rainstorms, and my uncle's battery car was not spared. When I took apart the controller of his battery car, I issued a death certificate to it. The insulating oil on the circuit board fell off in a large area, and the MOS There is a layer of white stains on the tube, and many original parts are rusted and broken. It has no salvage value at all, except for the STM32F104 chip on top (the price has increased ridiculously). This thing is like this and I don't dare to use it even after repairing it.

The casing of the electric vehicle controller is an aluminum heat dissipation shell, which can be used to hold lithium batteries. You only need to draw a drawing board and make a patch patch, and then use screws to install the circuit board directly in the openings at both ends. Chefette, perfect.

Schematic diagram

There is nothing to say about this. According to the chip manual released by Yingjixin, it is drawn strictly according to the DEMO, and the components use recommended models. Copper should be laid, copper should be laid, and vias should be used for vias.

PCB design

Use vernier calipers to accurately measure and draw the screw holes to make sure they fit perfectly. Awesome. It is worth noting that the inductors used for boosting and bucking need to be in large packages to facilitate heat dissipation. If they are too small, they will be very hot. For people like me who only want safety and not other things, just go for the one-piece type. The molded inductor is 12mm*12mm. It is not hot at all according to the actual test. Maybe the heat dissipation is too good.

Regarding the heat dissipation issue, I have been thinking about how to do it best, and I have spent a lot of energy to compress the double-layer board into a single-layer board (a lot of jumpers and 0 ohm resistors) in order to be able to build it on an aluminum substrate, but the aluminum substrate requires The diameter of the drill holes was too large, and the resulting board was unusable and welding was very troublesome, so I gave up and used a fiberglass double-layer board, which had a much lower heat dissipation capability.

As shown in the picture: (I'm really sorry, the camera of my mobile phone was broken and the pictures are blurry. I am not going to repair it until I change my phone)

Physical assembly

A problem was discovered during the actual production. There was a component that could not be purchased. Since I was drawing a digital tube that displays the percentage of electricity, the type of digital tube required by the technical manual was not available, so I had to leave it temporarily vacant. I will wait for it according to the circuit diagram later. Make one yourself to make up for it.

Material cost accounting: (for your reference)

Total: around 150 (excluding casing).

In total, the cost of this power bank is not low, but the capacity is real, and it has full protocol two-way fast charging.

In actual use, I found that it is not convenient to carry. It can only be used in backpacks or when traveling, and it cannot pass security check, right?

Improve

In the later stage, a casing was added to cover the circuit board. Many people could not accept the exposed circuit board. Although they said that you must be awesome next time , in fact they stayed away from it.

Plus the unfinished digital tube shows the current percentage of power!

BUG

PS: In USB2 (i.e., the left USB port), a fast charging protocol higher than 18W will be activated, which will result in power failure and interruption. USB1 (right USB) will not.