This dismantling was carried out by a team called Ranger Car in China, and was reported by the GeekCar team. The former wants to be a pure electric vehicle. Two months ago, he transformed a second-hand modern Coolpad sports car into Demo and successfully ran it. In order to learn from Tesla, they even bought a Tesla for disassembly.

Tesla's 85kW • h battery pack consists of nearly 7000 18650 lithium batteries. But few people have seen the actual situation of the battery pack. The battery analysis published online before is mostly based on Tesla's battery patents. The focus of this report, of course, is Tesla's batteries.

Battery module

This is a panoramic view of the entire battery pack of the Model S chassis. Model S has 16 battery packs in total, and the bottom neutral one originally had two batteries.

Tesla covers each battery pack with a fiberglass board for simple protection. Every two batteries are separated by a metal beam. In the figure, the lower left corner is the fuse of the whole battery pack, and the right side is the coolant interface and coolant filler of the battery.

Single battery pack

This is Tesla's very tall lithium battery pack. There are 444 batteries on this board, 74 of which are connected in parallel to form a group. The whole battery panel is composed of 6 groups of batteries in series. So we can calculate that there are 7104 18650 lithium batteries in this Tesla Model S 85.

See the red line above for the layout of 6 partitions of the battery pack. The structure of the front and back sides of this battery panel is central symmetry. As for why it is arranged like this, it must have been tested and verified by a lot. GeekCar guesses that this arrangement is to achieve lower average resistivity and better heat dissipation with heat dissipation pipes.

The wires in the middle of the battery pack are connected to the battery plate on one side and the battery control module on the other side. These wires are used to detect the voltage of the battery pack to ensure the normal operation of the battery pack.

A closer look shows that each battery has a very thin fuse, which is used to protect the entire battery pack. When a single battery has abnormal phenomena such as excessive temperature, the fuse will automatically blow to protect the entire battery pack (there will be a fuse at the positive and negative poles of each battery).

It is a very big project that so many fuses need to be welded on the circuit board. Technically, it should be completed by a special robot using ultrasonic welding.

BMS master chip

According to the logo printed on the PCB of Tesla's battery master module, this circuit board is completely developed by Tesla itself. A large number of resistors and capacitors are used on the circuit board for signal conditioning. There are six groups of electrical signal acquisition lines on this side alone.

Because Tesla uses 18650 lithium batteries, which are the batteries used in our laptops, its electric control technology is very mature. Although I have tried many ways to see the model of the chip on the motherboard, I can still speculate that there are mainly charge and discharge management chips and battery metering management chips on the surface. Compared with notebook batteries, The complexity lies in the multi-channel battery signal acquisition and control algorithm. After all, the monitoring of hundreds of batteries in electric vehicles and about 10 batteries in laptops is not on the same order of magnitude.