Yesterday, a friend sent a picture and said that he made it. What can I say, it’s too Versailles (my self-confidence was severely hit). With the iteration of battery-based technology in China, in another five years, it is estimated that the domestic circle will dominate the compo

Yesterday, a friend sent a picture and said it was made by him. What can I say, it’s too Versailles (my self-confidence was severely hit). With the iteration of battery-based technology in China, in another five years, it is estimated that the domestic circle will dominate the component design of many of the world's top models.

Figure 1 12V lithium battery on Model S Plaid

Let’s briefly summarize the situation of this battery. This is a 99Wh lithium battery. The specifications and configuration are quite different from the previous A123 LFP solution. We estimate the rated voltage to be 15.5V. If converted to 1P4S, it uses a ternary battery (according to the battery rate, it is more likely that the HEV battery used before reuse uses NCM111). This battery is particularly small in terms of overall energy and capacity.

Figure 2 The parameters of this 12V battery

Figure 3 The installation position of the 12V battery

Compare the 528Wh 40Ah & 13.2V lithium battery used on the Taycan we mentioned before.

Figure 4 A123’s 528Wh 12V battery

Here are a few questions and guesses:

1. Is it difficult to control such a small battery? There is only NCM 6.9Ah compared to LFP's 20Ah. If DCDC does not work for a particularly long time, this 6.9Ah will be difficult to withstand Tesla's current demand on the 12V bus. My personal understanding is that Tesla may have further updated the overall high-voltage battery power-off strategy when using such a small battery. This DCDC works for a long time. There will be at least a 12V battery detection mechanism to ensure that the power of the 12V battery will not enter a deficit state.
2. The second guess is that a built-in high-voltage to low-voltage self-starting mechanism may be used. If you use this 12V battery, you must prevent the battery from going into power loss, that is, there is no logical 12V situation as a whole, that is, a low-power power supply is needed to enable DCDC to start in any state of the 12V battery.
3. Third The first guess is the power supply of the actuator based on L2+. If Model S is supplied to FSD, how can the power supply of the main execution components such as EPS and braking system, and the hardware computing platform be ensured to be reliable? Assuming DCDC is abnormal, the time that 100Wh 6.9Ah can sustain under larger current demand is very short

Of course, given that the Model S The primary design goal of Plaid is unparalleled acceleration, so it is logical to reduce the quality of the entire vehicle and reduce the 12V power supply. There is a deviation in the demand for robustness of high-end autonomous driving.

Summary: I actually There are still many things we don’t understand, but I believe that the mysterious power of Tesla + Dongfang will make further rapid iterations. Thanks to this era for allowing us to be exposed to interesting designs and interesting ideas.