Microsoft's battery management technology, do you understand?

Consumer cells, because the need for electricity devices relatively small, single cell output can meet the basic requirements, so few need to work together with a few cells. The single cell has a small electric quantity, and when it comes to the application occasions with high electric quantity output, such as electric vehicles and energy storage, a lot of cells need to be connected in series and in parallel to obtain relatively high output voltage/electricity/current/power. As shown in the figure below (figure 1 and figure 2), many square and cylindrical cells (18650) are combined into a module, and many modules are combined into a pack to serve as the power source of electric vehicles. Someone on the Internet has taken apart the tesla modelS, 85Kwh battery pack, and 7104 panasonic cylindrical cells, which are connected in parallel every 444, a total of 16 groups, in series between groups, to form the battery pack.

If Mr Musk dares to do so, it is not necessarily anyone's guess. First, panasonic's small cylinder technology is highly refined, with low cost and consistent performance. There is a joke that if you use two machines to test a panasonic battery, the first thing you suspect is your testing problem. The production process of the battery is complex, and there are many factors affecting the cell consistency. From the beginning to the end, in addition to the consistency of the material itself, there are also such factors as ingredients/mixing/coating/cold pressing/slitting/winding/liquid injection/chemical conversion, etc. In order to improve the consistency of battery delivery, battery manufacturers will also increase the sorting process after the production to select those batteries with large resistance deviation/serious self-discharge. If the cell consistency is not good, it will seriously affect the service life of the battery and shorten the service life of the battery pack. After charging and discharging for many times, due to the increase of SEI film on the surface, the adverse reaction and the blockage of the isolation film, the reversible capacity will decline to some extent. When the capacity reaches 80% of the initial capacity, the design function of electric vehicles will be seriously affected. If the battery cells in the module are inconsistent, some batteries will be over-charged or over-discharged when the same current is used for charging and discharging, which will greatly shorten the overall cycle life of the battery, and the inconsistency will lead to a domino effect chain reaction of other monomers in the battery. For example, for a cell with a cycle life of about 1000 times, the actual cycle times in the battery pack are only about 200 times. However, if the consistency of the cell is not good, can the groups still be used?

Traditional BMS are definitely rejected, but not if it is SDB(softwaredefinedbattery). A traditional BMS comes in with a charging cable that charges/records/closes all the batteries before output. If the cells are less consistent, the problems described above can occur. Further, if we get a little more imaginative, I put two batteries in my battery pack, one for low power discharge at low cruising speeds and one for high power discharge at high breakdowns. Different cell systems have different characteristics, and the energy density/power density/cost/life/flexibility and other indicators that are often considered are also in conflict with each other. If different cell systems need to be used in the same module to produce a product with outstanding comprehensive performance, traditional BMS will be more difficult.

Microsoft feel, this can do: give every cell with a charge discharge management micro devices (smartswitchingcircuitry), collection of each battery charge and discharge voltage/current/resistance, implement intelligent triage allocate, make each batteries batteries to charge and discharge conditions close to the monomer, to maximize the use of batteries. The main difficulty with this cell management model is the analysis and current allocation after collecting this data. Microsoft has developed a more sophisticated algorithm for this model and has implemented a battery pack using this battery management model as softwareedbattery.

More importantly, this battery management mode can realize the mixed management of different chemical systems. Energy storage modes vary in their advantages and disadvantages. With different voltages/resistances/charge/discharge ratios, will these batteries work together? So, Microsoft ran an experiment with SDB, and I got good results (batterymanagement for2-in-1s). In addition, in a smart watch, flexible solid-state battery can be assembled with the watch strap, and polymer lithium battery under the dial can better extend the standby time, which requires SDB to better regulate the cooperation between solid-state battery and liquid battery.

As for so many charge and discharge the introduction of micro devices, money (cost) problem, bosses said "are not (WebelievetheBoMcostandspacerequirementofourSDBsolutionwillnotbesignificant)". In the future, this SDB system will be connected to the Internet of things of the vehicle, understand your personal behavior and schedule of users, and serve your travel. Ah, our battery also big data Internet of things up, foreign.

The page contains the contents of the machine translation.