Recently, a news in the field of power batteries has attracted attention: CATL (Times Electric Service) released the power exchange service brand EVOGO and the overall solution of combined power exchange, that is to say, CATL through its wholly-owned subsidiary Times Electric Service, to create a mobile power solution service.
For this matter, the question I want to explore is --
1) The scheme made around the Ningde era can surpass the snap-on power exchange of Aodong?
2) Can Nio's car company solution open up the design of various auto companies and become a standard third-party solution?
Figure 1 Combined use of power exchange block, quick change station and APP
Part 1: The problem of matching battery systems and cars
The main features of the "chocolate power exchange block" in the Ningde era include the following -
1) The design of a single battery is 26.5kWh, which aims to provide an endurance of about 200 kilometers
From the following figure, it is done by decomposing the battery. That is to say, in order to adapt to different sizes, batteries of different sizes are configured. The single block only considers the high-voltage connection, which can reduce the design difficulty of the high-voltage quick-change connector.
Fig. 2 Design of chocolate blocks
2) Freely combined matching mode
According to the combination of this logic, the entire power exchange system can provide different solutions - 1 block (26.5kWh), 2 blocks (53 kWh) and 3 blocks (79.5 kWh) solutions. Specifically, we can guess that this system actually adopts the parallel connection method that is more commonly used on the bus system in the Ningde era, and is paralleled through the internal high-voltage relay.
Figure 3 Freely combined system
Here's the central question: How do you hook up these three batteries?
According to the reply of the Ningde era, structurally this means that three battery blocks need to correspond to a battery holder. In the same way, three battery carriers need to be pre-installed on the car, and the high-voltage line and cooling line are pre-installed and fixed.
3) Electrical design
It is precisely because of this that wireless BMS technology needs to be used, and there is only a high-voltage positive and negative interface outside, otherwise the three batteries will be connected and communicated with the outside.
My understanding is that in order to match these three different configurations of batteries, it is necessary to have a very flexible battery management system networking strategy, and a separate networking device needs to be installed on the car to configure it.
Figure 4 Automotive wireless communication technology for the next generation
For electrical suppliers, multiple distribution settings are required here – I think if you want to achieve high-voltage paralleling, each battery pack needs to have a positive, positive, positive, and precharge system, and then with independent current sensing. Each BMS needs to do nearly 100 cell acquisitions.
Note: My biggest question here is whether the NINGDE era will give up the technical route of large batteries; that is, even if the latest CTP technology of the NINGDE era is adopted, according to the design of 26.5kWh, the battery capacity is about 70Ah, and this capacity may return to the battery cell specifications of VDA. Although the weight energy density exceeds 160Wh/kg and the volume energy density exceeds 325Wh/L, from a cost point of view, it is not similar to the current direction of propulsion.
One of the more interesting things is the design of the change station. Because the overall battery block is relatively small, so the subsequent overall stacking is relatively easy, thanks to this, the supporting express station has the characteristics of small footprint, fast circulation and large capacity. A standard station only needs three parking spaces, a single block can be replaced for about 1 minute, and 48 power exchange blocks can be stored in the station. In this sense, the density of stacking and arranging from a single layer here is quite high.
Figure 5 EVOGO substation design
Of course, the power exchange mode still has many problems in China. First of all, from the perspective of automobile companies, if the Ningde era is successful, it can be said that the OEM does not even have the basic design right in the field of battery design. The strategic purpose of this "chocolate replacement block" is to make all brand models available, break through the adaptation barriers between batteries and models, and realize the freedom of choice of power exchange models. That is to say, this time can actually break the problem of non-standardization of batteries, this kind of third-party power exchange scheme, can be used by different vehicle companies.
I think this matter is done by Ningde, which supplies more than half of China's batteries, or it may be successful, after all, the product covers most of China's automobile companies.
Remarks: As long as this plan can make the management feel feasible, this matter is mostly successful, and it has nothing to do with the wishes of the car company.
Figure 6 The situation of various suppliers of power batteries in China in 2021
On the other hand, for most consumers, consumers can "rent electricity on demand" and freely choose the number of rented replacement blocks according to their own usage scenarios and habits. Through the "on-demand rental of electricity", consumers only need to rent one power block for daily commuting in the city; if they want to travel long distances, they can choose two or three power blocks, which can really increase or decrease, and realize the freedom of electricity. This kind of exploration is actually very inspiring, but it needs to solve a concurrency problem, and it is easy to think of it and difficult to implement.
brief summary:
My understanding is that regardless of whether the power exchange scheme in the Ningde era is successful or not, there is really no need for so many auto companies in the market to design some different battery systems, that is to say, under the Matthew effect in the next stage, instead of becoming the first-class and large-scale automotive enterprises, they can only be reduced to the B side that passively accepts the plan. We may only need to focus on promising auto companies, and the follow-up that is not large will be very passive.
Figure | network and related screenshots
About author:Zhu Yulong, senior electric vehicle three-electric system and automotive electronics engineer, author of "Automotive Electronics Hardware Design".
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