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SmartLi Smart Battery Solutions for Modular UPS

In the next post from the series devoted to new Huawei products, we will talk about how our smart technologies have found application in uninterruptible power supplies with a modular design and what are the benefits of using SmartLi lithium-ion batteries.



Before moving directly to the new “lithium” UPSs of modular type, it’s worthwhile to explain that today we supply a whole range of uninterruptible power supply, cooling systems, as well as a number of complex FusionModule solutions, many of which will be mentioned below. They are divided into several classes.

First of all, uninterruptible power supplies deserve attention. At Huawei, they are divided into two categories: (a) UPS2000 series, designed for small loads - from 1 to 20 kVA; (b) UPS5000 series, designed for medium and heavy loads - from 25 (30) to 1600 kVA. All UPSs have a double conversion topology (on-line), that is, they provide maximum load protection against any network outages. Traditionally, all Huawei Uninterruptible Power Systems work with lead acid batteries (VRLA). Since last year, the company has been producing solutions with lithium-ion batteries (SmartLi) for UPS5000 series modular UPSs (more about them later). In the III quarter of 2020, we are going to start producing low-power UPS with lithium-ion batteries.

Further, the NetworkEnergy range includes power distribution devices of both rack-mount type and data center level, consisting of one or more power cabinets. In a special category stands out the element-by-element monitoring system for lead-acid batteries called iBattery.

There are also comprehensive solutions consisting of several products, such as UPS with battery, power distribution devices, precision air conditioners, IT cabinets, corridor isolation systems, monitoring system. For relatively small data centers (server or switching), Huawei offers complete solutions for installation inside prepared rooms: FusionModule500 (3–9 kW for IT load), FusionModule800 (up to 25 kW for IT load), FusionModule2000 / 50000 (up to 400 kW for IT -loads on the module), comprehensive solutions for external placement (as part of container data centers) - starting with the standard all-in-one FusionModule1000-A model (up to 54 kW for IT load) and ending with the FusionModule1000-B designed for prefab data centers under any tasks.

It is important to mention the cooling system, which includes in-line and cabinet precision air conditioners. All of them are divided into two groups - according to the type of refrigerant (freon or chilled water). There is a solution with indirect cooling of the data center - NetCol8000-E (FusionCol), which provides a free-cooling mode and has a cooling capacity of up to 400 kW per module.

All these solutions can be combined using the NetEco6000 DCIM central monitoring system, which can interact with both the previously mentioned Huawei models and with third-party equipment using standard SNMP or Modbus protocols.

Let's dwell on Huawei megawatt-class solutions, united under the UPS5000-S (FusionPower) brand. Several of these systems are already operating in the data centers of large Russian customers.

FusionPower5000 High Power Modular UPS Family


Last year, we announced FusionPower5000 models with 1.2 and 1.6 MW power (left and center of illustration) with 55 kVA power modules. In 2020, Huawei intends to announce a model with a capacity of 1.2 MW with power modules at 100 kVA. Note that this power will be available in the same form factor 3U high. UPSs with 100 kVA modules will be available for order in September this year.

Recall also that in addition to the images shown, Huawei supplies modular UPSs with 30 and 50 kVA power modules.

Briefly about the architecture of FusionPower5000. The solution includes up to three cabinets with 55 kVA power modules. Static and manual bypasses are located in separate cabinets, ABB circuit breakers are located in a separate rack, protecting power cabinets by input and output. Thus, Huawei offers a highly integrated solution for uninterruptible power systems, which is by far the most compact compared to competing ones.

In the UPS under consideration, power modules with a capacity of 55 kVA are used, and the maximum power is 1.2 or 1.6 MVA, depending on the configuration. The inverter power factor is unity. Total active output power of the systems is 1.2 and 1.6 MW, respectively.

The nominal efficiency of the system reaches 97%, and this is objectively one of the best indicators in the global industry of modular UPSs. And the significance of the parameter is by no means formal: with such capacities, every tenth percent of the efficiency directly affects the value of electricity bills.

If the UPS needs to be installed with the back wall close to the wall, it is advisable to use the optional kits with the heated air outlet up. Kits with a width of 400 mm allow maintaining the normal temperature conditions of the UPS, excluding the formation of a “hot corridor”. This makes it possible to further save space for the placement of the UPS. The same kit will be available for UPSs with 100 kVA power modules.

Reliability through redundancy and protection


The illustration above shows how the power modules are connected to the control system. For redundancy purposes, each UPS must have two control modules that use two CAN buses to communicate with the power modules and the static bypass. Due to this, the failure of any power module or CAN information bus will not lead to an accident or shutdown of the UPS. Power Modules, Static Bypass Modules, and Control Modules support Hot Swap, which allows you to service or repair the UPS as soon as possible without the involvement of vendor service engineers.

Each power module is equipped with quick fuses that automatically isolate it from the overall system in the event of an accident or internal short circuit. If an accident occurs with the power unit itself (cabinet), the circuit breakers placed in a separate rack come into play.

Reliability with iPower Monitoring


All modular UPSs of Huawei, including basic ones, with 25 kW power modules, are equipped with iPower monitoring system. It is responsible for monitoring the operation of fans and the service life of capacitors. In large UPSs that are connected by busbars, iPower receives additional information from temperature sensors located at the busbar junctions.

If necessary - optionally - the UPS is equipped with an iBattery system that allows you to organize element-by-element monitoring of lead-acid batteries in real time. So, iBattery is able to control the temperature of the batteries, their voltage, internal resistance and current level of the entire array. The system allows you to save significant money on periodic maintenance of the battery.

Efficiency Improvement Technologies


Last but not least, the high efficiency of the UPS provides an intelligent hibernation system. If a low load level is detected, redundant power modules are automatically turned off, and when the load increases, they are phased back into operation. So at virtually any load level, the UPS is highly efficient.

As in other companies' solutions, Huawei UPS has a function of automatically transferring the load from the inverter to static bypass (ECO mode), provided that the input power supply is within acceptable limits. By default, this mode is not activated, but can be enabled by the decision of the operator. In this case, the efficiency indicator exceeds 99%.
Reverse switching takes no more than 2 ms.

Another advantage of the FusionPower5000 is the ability to quickly connect input and output wiring using standard three-phase buses. Thus, according to our estimates, it is possible to save up to 60% of the time required for installation and startup.

Battery Cabinet Architecture


FusionPower solutions can work with both lead-acid and SmartLi lithium-ion batteries. Currently, Huawei uses batteries manufactured using LFP technology (LiFePO4), which is one of the safest. We will make a reservation that Huawei does not produce battery cells themselves, entrusting this process to a trusted supplier.

A standard battery cabinet with a width of 600 mm is equipped with 16 battery modules (two groups of eight modules). The total capacity of the entire cabinet is 80 Ah. Along with them, a DC-DC converter, a controller and a protection unit are installed here. The ABB automatic machine protects the system from overloads and short circuits. The controller is equipped with a seven-inch color screen on the cabinet door, where the current system operation parameters are displayed. Battery cabinets themselves can be combined in parallel arrays of up to eight pieces to increase the overall battery capacity and battery life.

Three-level BMS system


Additional reliability for SmartLi solutions is provided by an integrated three-level monitoring system.

The first level ensures the safety of each of the battery modules. Each battery module has its own controller. It controls the voltage of each cell, as well as the temperature inside the module. All collected information is transmitted to the central rack controller (second level), from where it is displayed or sent to a remote monitoring center. The second-level controller also implements a number of functions for managing battery modules, which will be discussed later.

The third level allows you to manage several cabinets with lithium-ion batteries both from the UPS itself, and with the help of a centralized monitoring system NetEco6000.

Active current balance control and modular design


Huawei solutions based on lithium-ion battery cells use an active current balance control system. First of all, it is necessary for the joint work of old and new battery cabinets or battery modules connected in parallel to a common bus.

Suppose a customer already uses SmartLi. When the load increases, it is necessary to ensure the same level of autonomy, which requires the connection of additional battery cabinets or the installation of additional battery modules. When using old and new battery packs together, the battery life will be reduced. In order to avoid such a negative scenario, the patented technology for managing the current balance is used.

Note that 16 battery modules installed in one cabinet do not support hot swapping, but they can be changed by turning off the circuit breaker. The entire capacity of the cabinet is divided into two groups of eight pieces. In each group, the failure of one battery module is allowed.

Moreover, the battery cabinet does not turn off: there is only a slight decrease in the potential load autonomy time. In this partial failure scenario, a DC-DC converter is used to equalize the voltage at the cabinet output.

As a result, to replace the battery module will not require any complicated technical procedures, nor call the vendor engineers.

Compare the power supply systems of the monitoring modules in Huawei battery modules (left) with the solutions of a number of other manufacturers (right). The main difference between our system is that the second input to the monitoring device is done directly from the battery. In addition, this solution does not require external switching equipment.

Safe Lithium Iron Phosphate Cells


The table above summarizes all the features inherent in various modern technologies for the production of lithium batteries. Data provided by APC. It is easy to see that, due to a combination of factors, LiFePO4 is now the most secure solution, which, moreover, differs in moderate cost.

If you study the LiFePO4 charging formula, it is easy to find that oxygen, which can cause a fire, is not released in the process.

LiFePO4 batteries are also safe for mechanical impacts. You can learn more about the tests conducted by experts of the independent international laboratory TÜV on batteries of this type from a short seven-minute video about testing the batteries used in our SmartLi solutions.



Benefits of LiFePO4 over VRLA


In terms of weight and size characteristics, the lithium-ion cells of Huawei SmartLi exceed VRLA by 60%. With equal indicators of power and autonomy, placing a battery on the basis of LiFePO4 requires three times less area than installing a VRLA of a similar class. The weight of the system (load on the foundation or floor) is also several times less. A fully equipped “lithium” rack weighs about 800 kg, while a cabinet with lead-acid batteries is about three times heavier.

In favor of LiFePO4, the fact that, to achieve the same battery autonomy, lead-acid batteries, for example, with a nominal capacity of 800 Ah, can be replaced by lithium batteries with a nominal capacity of only 300 Ah, is in favor of LiFePO4. Cells used in Huawei UPSs can withstand up to 5 thousand charge-discharge cycles at 50% discharge and up to 3 thousand cycles in charge-discharge mode at 100% discharge. The LiFePO4 battery life declared by the manufacturer is 15 years.

Finally, Huawei is ready to give a guarantee of up to ten years for its decision.

Cabinet level fire extinguishing system


All Huawei battery cabinets that work with lithium-ion batteries are equipped with a fire extinguishing system. A corresponding module is installed in each cabinet, acting on a signal from a temperature or smoke sensor. In the event of an alarm, combustion inside the cabinet is suppressed by the extinguishing agent.

The system is not designed to extinguish a fire throughout the room. Based on the results of a number of successful tests, the effectiveness of the solution was confirmed by a TÜV laboratory fire safety certificate.

A small remark: we deliver fire extinguishing systems in an unfilled condition, and gas filling with FM200 (“Freon 227ea”) is carried out after the installation of cabinets in the room.

A little about the achievements of Huawei in the UPS market


This is not the first year that the company remains the world leader in the market of modular UPSs. This was largely achieved thanks to the presence of several research laboratories, including outside of China, and considerable investments in the development of new technologies, including the improvement of uninterruptible power supply systems.

In order to promote SmartLi-line more actively in Russia in 2020, Huawei is ready to provide the cost of “lithium-ion” solutions at the same level as in the case of solutions with lead-acid batteries. As a result, in the power range from 100 to 500 kW and with an autonomy time of ten minutes, Huawei UPSs based on SmartLi batteries cost as much as traditional VRLA based UPSs with similar characteristics, equipped with an element-wise control system.

At the same time, the customer receives all the advantages associated with the use of LiFePO4 batteries, which was also appreciated by Russian customers of Huawei. As part of one of the implemented projects last year, Huawei has already delivered and deployed several megawatt-class systems with lithium batteries in the Russian Federation. So, they are installed in the new office of Sberbank near the business center "Moscow City". A few more systems were delivered under a contract with a large Russian company in the oil and gas sector.

All devices have EAC certificates.

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And do not forget about our many webinars held not only in the Russian-language segment, but also on a global level. A list of webinars for the coming weeks is available here .

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