Tianmei Automobile is a wholly-owned subsidiary of Kaiwu New Energy Automobile Group, and its first mass-produced model, Tianmei ET5 electric SUV, has a length, width, and height of 4698x1980x1696mm, and a wheelbase of 2,800mm; it is equipped with a 3-in-1 electric drivetrain that has a maximum rotational speed of 15,500 rpm, and a maximum output of 150kW. "3-in-1" electric drive assembly. The highest matching Tianmei ET5 vehicle weight of 1.9 tons, power battery assembly energy density of 170wh/kg, loading capacity of 71.98 kWh, NEDC range of 520 kilometers; according to the different configurations of Tianmei ET5 *** divided into four different models, but all the power battery system equipped with all the standard unique high-temperature cooling and low-temperature preheating function. Tianmei ET5 electric SUV can realize ACC full-speed domain adaptive cruise control, lane keeping and other L2 level assisted driving functions in terms of intelligent driving.
New Energy Intelligence and Analysis Network (NEAAN), on the unique battery technology of Tianmei ET5, originating from the parent company's Kaifu series of electric buses equipped with the standard R&D traction point of safety, the 3rd generation of all-aluminum box integrated liquid-cooled battery technology in-depth study of the intrinsic correlation.
1, Tianmei ET5 basic configuration introduction:
Wheelbase 2800mm Tianmei ET5 electric SUV was originally designed as a 7-seat model, after research into the large 5-seat model, which provides rear passengers with quite abundant leg and head space. The width of the vehicle is close to 2,000mm, which is fully reflected in the comfort of the front driver's and passenger's seats and the width of the rear seats, and the rear seat will not be crowded when riding with 3 adult men.
In addition, the 2800mm wheelbase in the space advantage and ride comfort at the same time, for the body welding bottom suspension of the power battery to provide a wider layout area, in exchange for more loaded power and more stable range.
The horizontal dashboard panel and air conditioning vents create a ladder-type spatial mismatch, and the horizontal central display provides control and display functions for all sub-systems in the car (excluding the exterior mirror adjustment function), while the lower switching and control components provide more convenience and safety for the driver to control the air conditioning and audio in the car (which can also be set in the multifunctional steering wheel). safety.
The Trimix ET5 features L2-level intelligent driver control, which allows the driver to activate/deactivate key functional options such as lane departure and lane keeping. Most importantly, the energy recovery level of the Tianmei ET5 can still be adjusted by the driver in the range of 20%-100%. In addition, the charging and discharging options also include deep battery discharge and charge insulation.
The battery deep-discharge function that comes standard on the Tianmei ET5 electric SUV helps stabilize the health of each cell in the power battery by discharging the cells to a lower SOC value and then recharging the battery to full capacity for vehicles that are used to fast-charging in the day-to-day life of the vehicle. The battery slow charging protection mode is still set to keep the SOC value of all cells balanced under slow charging conditions, effectively stabilizing the battery safety status.
The driver's display of this high end Tianmei ET5 electric SUV with 71.98 kWh of loaded power can output key data such as travel speed, range, maximum power, SOC value of the power battery, and 100km of homeopathic power consumption.
2, Tianmei ET5 electric drive technology status:
The above picture is a close-up of the details of the status of each sub-system of Tianmei ET5 front powerhouse.
Red arrow: "3-in-1" charging and distribution system assembly (integrated OBC\DCDC\PDU)
Blue arrow: PTC control module with a maximum output of 7 kW
Yellow arrow: water-cooled plate control of the servo power battery thermal management system's low-temperature preheating function Module
Green arrow: coolant refill jug for the electric drive system and the power battery thermal management system***
White arrow: electro-hydraulic integrated iBoost brake master cylinder
Removing the front powerhouse dust cover, you can see the Tianmei ET5's electric drive system, the vehicle control system, and the ancillary power battery thermal management sub-system. It should be noted that, as the first electric car model of the Tianmei brand, the layout of many sub-systems in the power compartment of the Tianmei ET5 is a bit messy. However, the cooling piping connecting each subsystem is laid out in a very clear structure. In addition to the 3 groups of necessary electronic water pumps of different powers, there are only 2 groups of "3-way" valves in the whole car.
Yellow arrow: "3-in-1" charging and distribution system assembly
Red arrow: vehicle control system
The vehicle control system of Tianmei's ET5 electric SUV, as well as the "3-in-1" charging and distribution system that integrates the OBC\DCDC\PDU, are all in one. The entire control system of Tianmei ET5 electric SUV and the "3-in-1" charging and distribution system integrated with OBC\DCDC\PDU are all developed and mass-produced by the Central Research Institute of Kaiwu Group. As the parent company of Tianmei, many electric buses, electric coaches and electric trucks manufactured by Kaiwu Group are equipped with the "X-in-1" charging and distribution system assembly and vehicle control system developed by Kaiwu Group's Central Research Institute. The "3-in-1" charging and distribution system technology of the Tianmei ET5 electric SUV performs well in the region compared to the higher power control required by electric buses and trucks.
In the front-to-power compartment of Tianmei ET5, there is only one set of coolant-based PTC control module with a maximum power of 7 kilowatts, which is used for cockpit air-conditioning heating and low-temperature preheating of the power battery. Compared to joint venture brand electric vehicles such as Beijing Mercedes-Benz EQC, FAW Audi eTron and SAIC-GM Buick Micro Blue 420, which adopt the technical architecture of 2 groups of coolant-carrying, different power PTC control modules, the control of Tianmei ET5 is simpler.
The above picture is a close-up of the technical status of 1 group of water-cooling plate control module set in the firewall of the front-to-power compartment of Tianmei ET5 electric SUV. In the whole set of power battery thermal management control system, the water-cooling plate control module, PTC control module, electronic water pump and power battery are connected in series to form a group of pipelines and provide low-temperature preheating and high-temperature heat dissipation servo for the electric core through the heated or cooled coolant. The water-cooled panel control module is associated with the electric air-conditioning compressor and carries out the exchange of "cold volume", and pumps the coolant after cooling into the power battery to dissipate the heat of the battery cell.
Tianmei ET5's "3-in-1" electric drive system and "3-in-1" charging/distributing system assembly*** use one set of cooling pipes, and the power battery thermal management system uses a separate set of circulating pipes. However, the Tianmei ET5 electric SUV does not set up a separate refill pot for the two sets of circulating pipes, but adopts the "**** enjoyment" method.
Red arrow: power battery thermal management system circulating line inlet
Blue arrow: power battery thermal management system circulating line outlet
Green arrow: electric drive system and charging/distributing system **** circulating line inlet
Yellow arrow: electric drive system and charging/distributing system **** circulating line outlet
The control strategy of the electromagnetic thermal management system of Tianmei ET5 will be analyzed in depth later in the article in conjunction with the charging power performance.
The braking system of the Tianmei ET5 electric SUV adopts iBoost technology, which integrates braking, energy recovery and ABS safety settings through electro-hydraulic integration. The iBoost braking system, developed for electric vehicles, has a vacuum boost requirement, but also improves the efficiency of energy recovery and makes the braking feeling more linear.
3, Tianmei ET5 power battery thermal management control strategy:
The interpretation of Tianmei ET5 electric SUV's power battery thermal management control strategy is carried out in the comparison of fast charging mode and high load driving mode. Charging tests were conducted on the Tianmei ET5 in the late afternoon when the outdoor temperature reached 38 degrees Celsius, using a 240 kW (dual 120 kW) fast-charging pile made by Kaiwu.
Nanjing Chuangyuan Tiandi Power Technology Co., Ltd, which is part of the Kaiwu Group, is in the business of supplying power battery assemblies (including modules), drive motors and control strategies for all sub-systems, including the entire vehicle, for Kaiwu's electric buses, electric station wagons, electric logistics vehicles, electric trucks, as well as for the Tianmei-branded ET5 and subsequent models.
Because the Tianmei ET5 electric SUV used for the test had an SOC value of 90%, a fast-charging current of 54.8 amps, and a cell temperature of 23 degrees Celsius, it was in a "trickle" state and did not reach full power.
Through the thermal imaging camera, the SOC value of the power battery of the Sky ET5 is at 90% for fast charging, the charging power does not reach the full load state, and the temperature of the battery cell is only at 23 degrees Celsius, which does not meet the activation threshold for the activation of the high-temperature heat dissipation function of the activation of the thermal management system of the power battery.
Green arrow: the temperature of the electric air-conditioning compressor to the condensing line dips to 13.6 degrees Celsius after the cockpit air-conditioning cooling function is activated
White arrow: the surface temperature of water-cooling plate control module is at 23.5 degrees Celsius
At the same time, the surface temperature of the Trimax ET5's front power compartment refill kettle is at 41.6 degrees Celsius, and the temperature of the internal coolant is maintained at 42-44 degrees Celsius. 42-44 degrees Celsius.
During the fast-charging test, only coolant from the electric drive system (including the charging and discharging system) was circulating in the only set of refill jugs in the Tianmei ET5 (red arrows), while no coolant flowed into the circulating lines of the thermal management system for the power battery.
Despite the fact that the power battery charging current did not continue to rise, the temperature of the battery cell climbed from 23 degrees Celsius to 35 degrees Celsius, at which point the high-temperature heat dissipation function of the Tianmei ET5 Power Battery Thermal Management System was activated, and the water-cooling board control module introduced the "coolant" from the output of the electric air conditioning compressor to the cooled battery. The coolant is pumped into the power battery assembly to cool down the battery cells.
Green arrow: the temperature of the condensing line from the electric air-conditioning compressor to the condensing line dips to 8.6 degrees Celsius after the cockpit air-conditioning refrigeration function is activated
White arrow: the water-cooling plate control module surface temperature is at 7 degrees Celsius
It should be noted that the mainstream electric vehicles of domestic brands sold in 2020 will adopt a single coolant-based PTC control module for the battery low temperature warm-up, and the coolant will be used to cool down the power cell assembly. battery low-temperature preheating, cockpit air-conditioning heating using electrically heated PTC control module, heating/preheating efficiency is higher (the conclusion on whether it is energy-saving to be given after the completion of the evaluation).
The Trimax ET5's coolant-carrying single PTC control module technology controls the flow of heated coolant through a set of 3-way valves, either to the cockpit air-conditioning system for heating, or to the interior of the power battery for low-temperature preheating of the battery cells.
Red arrow: piping from PTC control module to "3-way" valve body
Blue arrow: "3-way" valve body
Yellow arrow: "3-way" valve body to cockpit air conditioning system
Yellow arrow: "3-way" valve body to cockpit air conditioning system
Yellow arrow: "3-way" valve body to cockpit air conditioning system
White arrow: "3-way" valve body to power battery piping
In low-temperature charging conditions, TMI ET5 utilizes the power from the charging post to activate the PTC control module, which heats up the coolant to achieve a low-temperature preheat for the power battery. The ET5 uses the power from the charging post to activate the PTC control module to heat the coolant to warm up the power battery at low temperature. If the cockpit air conditioner is turned on at this time, the "3-way" valve body will deliver the heated coolant to the cockpit air conditioner and the power battery. Since the maximum temperature of the coolant needed to warm up the power battery will not exceed 20 degrees Celsius (usually set at 15 degrees Celsius), the coolant temperature needed for the cockpit air conditioning warm air can reach 70 degrees Celsius or higher.
The "3-way" valve body, which does not have a temperature regulating function, therefore controls the flow of coolant to the power cell recirculation line more accurately, and has been able to meet the technical demand for temperature by reducing the flow rate.
The setup of 1 group of coolant refill pots adopted for the Tianmei ET5 electric SUV represents that the circulating pipeline of the electric drive system and the circulating pipeline of the thermal management of the power battery should not only meet the flow of coolant at different temperatures but also increase the number of pipelines to enhance the reliability of the system, which emphasizes the comprehensive hardness of Tianmei as well as the Kaifu brand behind it in the past years of application of new energy commercial vehicles and the research and development of the core technology. This highlights the comprehensive strength of Tianmei and the Kaiwu brand behind it in the past years of new energy commercial vehicle application and core technology development.
3, Tianmei ET5 power battery safety:
Tianmei ET5 electric SUV equipped with a "3-in-1" charging and distribution system assembly, as well as other models hanging Kaiwu brand equipped with the "X-in-1" charging and discharging system assembly, electric drive control assembly, and the "X-in-1" charging and discharging system assembly. The "3-in-1" charging and distribution system assembly, the electric drive control assembly, and the power battery (including the BMS system) are all developed and mass-produced by the Kaiwu Group's Central Research Institute in Nanjing (some of the power battery systems are manufactured by Kaiwu Group's ChuangYuanTianDi Power Technology Co.)
Kaiwu Automobile Central Research Institute, mainly for different types of battery cells, power battery assembly, thermal management system with multiple strategies, fuel cell system and electric drive and hybrid multi-gear transmission and other sub-systems to pre-research, research and development, and all the technical support needed before mass production. At present, all the power battery products of Nanjing Chuangyuan Battery from development and design, to product testing and certification, to product finalization and mass production design are comprehensively evaluated and verified by the R&D team of Nanjing Chuangyuan and the Central Research Institute, which guarantees the excellent quality of the products. As the most important power battery development direction for electric buses, the Central Research Institute of Kaiwu Automobile, together with the battery technology team of Nanjing Chuangyuan, always carries out cutting-edge prediction and research and development at the industry level for different kinds of electric cores and power battery solutions, so as to provide customers with high-quality power battery system solutions.
The picture above shows the power battery rapid temperature change environment warehouse and the battery cell testing system of Kaiwu Automobile, which is set up in the public *** technical service platform of the Central Research Institute.
Blue arrow: charging and discharging cycle test for soft pack lithium ternary cells at room temperature
Yellow arrow: charging and discharging cycle test for 18650 lithium ternary cells at room temperature
Red arrow: charging and discharging cycle test for square lithium ternary cells in simulated high temperature environment (Power Battery Rapid Temperature Change Environment Chamber)
Kaiwu The Central Research Institute of Automotive mainly conducts pre-research, R&D and all the technical support needed before mass production for different types of batteries, power battery assemblies, thermal management systems with multiple strategies, fuel cell systems and sub-systems such as electric drive and hybrid multi-gear transmissions.
The cylindrical 18650-type lithium ternary batteries are mostly divided into nickel-cobalt-aluminum and nickel-cobalt-manganese 2 categories, the former is used in Tesla Model?SModel?X and Model?3, and the latter is used in the domestic low-end and other non-mainstream electric vehicles. As we all know, Tesla's entire lineup of models equipped with 18650-type and 21700-type cylindrical lithium ternary battery systems have been involved in nearly 60 accidents involving fires, burns and explosions around the world.
The cylindrical 18650 lithium ternary batteries tested in the puncture test did not explode, but the burn marks were obvious. For cylindrical 18650-type or 21700-type lithium ternary cells, bench simulation of full life cycle charge and discharge attenuation test helps manufacturers to specify the forbidden and complete power battery thermal management control strategy. But the inherent lack of security is not a problem that can be remedied by later "software" control.
For the selection of soft pack lithium ternary cells, Kaiwu conducted safety and control tests as early as 2014. Square lithium ternary cells have a lower energy density than soft pack lithium ternary cells before the objective exists, through better temperature management measures, can effectively improve the energy density of the power battery assembly, or increase the range, or reduce the dead weight.
Red arrow: square Li-ion ternary cell
Yellow arrow: soft pack Li-ion ternary cell
By 2020, the Kaiwu Group Research Institute will have developed three generations of on-board power battery solutions for its electric buses and electric trucks. The 1st generation battery system (shown above) is based on an air-cooled heat dissipation + electric heating control strategy. It is mainly used in cities and villages in northern China where the summer temperature is not high.
The 2nd generation power battery solution is based on square Li-ion ternary cells (modules) + steel/aluminum battery case with built-in circulating piping (coolant) and temperature control system. Due to some overlap between the development of the 2nd generation power battery system and the 3rd generation battery technology, and in conjunction with the establishment of the Sky ET5 electric SUV, the 2nd generation battery technology was shifted to passenger cars, and the new 3rd generation battery technology was used for commercial vehicles.
Red arrow: coolant inlet and outlet set at the front of the 2nd-generation power battery case
Yellow arrow: liquid-cooling plate inside the 3rd-generation all-aluminum case-integrated liquid-cooled battery
The photo above shows a close-up of the 3rd-generation all-aluminum case-integrated liquid-cooled battery, which is widely used in the Kaivu line of electric buses. This technology of integrating the liquid-cooling plate directly into the aluminum alloy battery box (bottom) directly avoids the safety accident of short circuit caused by the rupture of coolant pipeline, and simplifies the structure and reduces the dead weight. For the higher safety requirements of electric buses (buses), modular, lightweight and thermal management of the power battery system to protect the tight, and has not become a mandatory specification for China's electric bus industry in 2020.
The author has something to say:
Tianmei ET5 electric SUV is equipped with the power battery technology applicable to passenger cars, and the 2nd generation of liquid-cooled battery technology used in Kaiwu electric buses, and the 3rd generation of all-aluminum box integrated liquid-cooled battery technology, there are too many technical intersections, and has been practically applied in the terminal market for more than 2 years.
Unlike Azure, Ideal, Weimar and other new car-making forces, the first model of Tianmei ET5, the introduction of electric drive technology, power battery and control strategy is not a brand-new state, but rather in different models for long-term terminal market reliability verification.
Of course, whether mature subsystems integrated into a brand new model platform equals better reliability is subject to subsequent market performance.
New Energy Intelligence Analysis Network Review Group
This article comes from the authors of Automotive Home, and does not represent the views of Automotive Home.