Detailed Analysis of BYD Electric Heavy Card Electric Drive Technology

1.BYD Electric Heavy Card Overview

(1) BYD T8 pure electric sanitation car

The T8A has a length of 8870mm and a full load of 16 tons. The T8A is positioned as a medium and heavy garbage collection and transfer vehicle. The electronic control system is optimized to make it more suitable for sanitation operations. At the same time, corresponding adjustments are made to the transmission system to make the walking system consume less power at low speed.

T8A uses a lithium iron phosphate battery with a capacity of 270Ah and an operating voltage of 650V. Batteries will be affected under extremely cold conditions, resulting in a decrease in vehicle life and working hours. When it first arrived in Harbin, the T8A's endurance capacity dropped by about 40 %. In response to this situation, the BYD test team adjusted the electronic control system, optimized the battery strategy, and eventually controlled the lifetime attenuation to about 10 %.

(2) BYD T10 pure electric dump truck

T10ZT's chassis drive form is 8 × 4, which is often referred to as the top four rear eight models. The size of the vehicle is 9610 × 2550 × 3210 mm.

The T10 is a front double steering bridge, a rear double drive bridge, and a standard 2 +2 set of airbag suspensions with a maximum climbing slope of 50 %. A new U-shaped cargo box with a volume of 10.6 cubic meters is installed and an aluminum alloy top cover closed system is installed. Equipped with a lithium iron phosphate power battery, the vehicle has a power of 435 kWh, which can be filled for one and a half hours and has a full mileage of more than 280 kilometers.

The cab adopts a four-point suspension structure, and a cab lateral shock absorber is installed. In addition, an ergonomic airbag seat can be well adapted to the bumpy road conditions such as the construction site, which can effectively improve the comfort of the driver and reduce driving fatigue.

The pure electric driving form actually effectively relieves the noise inside the driving room. Many dump trucks using diesel engines work at high speeds when climbing, and the noise in the car will once exceed 70 decibels. The T10ZT, which uses pure electric drive, does not have the noise of a diesel engine during normal driving. The diesel engine under the cab is also replaced by a battery pack, which reduces the vibration of the cab.

In terms of vehicle power replenishment, pure electric models also have great advantages. Because the gas station is set up in the urban area, there are great safety risks, so it is said that the problem of refueling in the urban area also troubles many teams and drivers. The charging station can be popularized in every corner of the city, on the construction site or even on the roadside, and can even move to the next site following the end of the project. Can be done loading and unloading charging, rest charging, stop charging.

2.BYD Electric Heavy Card Development History

BYD began research and development of new energy trucks in 2012. It is the first company in China to invest in the research and development of new energy trucks. In 2014, BYD established the truck and special vehicle research institute. In late 2014, BYD independently developed and manufactured the T series super electric truck, which gradually went to the market, and entered the Chinese domestic market with the K series electric bus for sale and trial operation.

In 2015, the "7 +4" all-market strategy was put forward to promote the electrification of vehicles in seven major conventional areas such as private, rental, public transport, road passenger transport, urban construction logistics, urban commodity logistics, and sanitation, as well as four special areas such as warehousing, ports, airports, and mines.

In August 2015, at the "70th Anniversary of the Victory against Japan" military parade held in Tiananmen Square in Beijing, BYD and Beijing Hualing jointly produced the T8 series electric cleaning car wash.

From 2016 to 2018, BYD's different driving bridges, different loads, and different functions T series Super electric trucks were put into commercial operation in China and international markets.

Currently, BYD has introduced a total of T4, T5, T7, T8 and T10 Super electric trucks with different loads and different types of drive bridges(number). Its T4, T7 and T8 series have undertaken environmental conservation tasks in the main urban area and the administrative sub-center of Tongxian County in Beijing. In August 2015, BYD T8 series Super electric trucks were commercialized in bulk in the Beijing market.

3.Comparison of Power Performance of Pure Electric Heavy Card and Fuel Heavy Card

At present, the top four and last eight models sold on the market are in the 340-400 horsepower range. The largest can reach 460 horsepower, but the number of users used is very scarce. We compare a better known model on the market, using a more popular model and BYD T10ZT to see if its power system can meet the standard of 8 × 4 clay cars.

First of all, for a brand of 8 × 4 slag trucks, the maximum engine power is 375 horsepower and the maximum torque is 1800 N.m. The gearbox that matches it is a 12-block gearbox, with the highest gear speeding. The rear bridge uses an 18-ton class, with a main deceleration ratio of 5.262 rims. Calculate that the side torque of the head gear is 114,606 N.m, and the second gear is 89128 N.m. The maximum side torque can reach 7387 N.m.

Let's talk about BYD T10ZT, which is equipped with a pair of 180kW integrated motors. The maximum power of the two motors is almost 490 horsepower, while the output torque of a single motor is 1500N.m. The two motors can output a total of 3000N.m. The torque of .m is far superior to that of traditional diesel mucks, both in horsepower and torque.

The use of BYD's independently developed integrated motor wheel side deceleration bridge integrates a four-block gearbox in the car bridge section. The speed ratio of 44.3 can output 132900Nm of torque, and the speed ratio of up to 7.07 can output 21210Nm torque.

4 The Advantages of Pure Electric Heavy Card

A lot of people think that the price of a pure electric dirt car will certainly be much higher than that of a normal diesel vehicle. However, pure electric models are the trend of the current market, and their later use and maintenance costs are also very low.

The electricity consumption per 100 kilometers of T10ZT is 138kWh, and the electricity price in Shenzhen is almost 1.25 yuan/kWh. That is to say, it takes about 170 yuan to operate a hundred kilometers, and the fuel consumption of a diesel-soil truck of the same power is about 40 liters. According to the oil price of 6.75 yuan in Shenzhen, the 8×4 muck of the diesel model is calculated. The fuel cost of the car is almost 270 yuan, which is one hundred yuan higher than the T10ZT. Every 100 kilometers travels, the difference is 100 yuan, and the cost of one year can be imagined.

And one of the advantages of pure electric dirt cars is that their noise is much lower than that of diesel vehicles. According to the person in charge of the on-site construction, due to the low noise of T10ZT, their operating time can be extended. Without affecting the rest of the surrounding residents, the construction efficiency has been improved and the construction period has been shortened.

Let's also say that its battery, T10ZT, has great battery placement space, so its lithium iron phosphate battery pack has been installed in three groups, and the total capacity of the two groups of cells has reached 435 kWh. The 435kWh power allows the T10ZT to travel a distance of about 280 kilometers, which is fully capable of this kind of slag transportation with a small mileage.

5 Pure electric weight card low temperature test process

As we all know, batteries will be affected under extremely cold conditions, resulting in a reduction in vehicle life and working hours. BYD T8's T8A's endurance capacity dropped by about 40 % when it first arrived in Harbin. In response to this situation, the BYD test team adjusted the electronic control system, optimized the battery strategy, and eventually controlled the lifetime attenuation to about 10 %.

In addition, charging in extremely cold conditions is also a challenge. Compared with normal conditions, battery charging time will be longer than normal under extremely cold conditions, and batteries are prone to charging unsaturated conditions.

In particular, the lithium iron phosphate battery and control system, the 4AT electrohydraulic drive module, the drive motor and the integrated drive bridge that are not equipped with water-cooled high temperature heat dissipation and low temperature preheating function, and the technical state under different operating conditions in an extremely cold environment are tested.

The T8A Super electric truck had a range of 92 Kilometers at 76.7 per cent. According to the official information of the BYD commercial vehicle, the T8A Super electric truck equipped with a 175-degree lithium iron phosphate battery has an empty maximum mileage of more than 230 kilometers and a maximum full-load operating range of more than 175 kilometers.

In the early morning of January 15th in Harbin, the surface temperature was minus 23 °C. The surface temperature of the grille in the front of the cockpit of the BYD T8A Super electric truck was minus 18 °C. At this time, the vehicle started for 2 minutes. Preheat.

The surface temperature of the No. 1 power battery assembly shell exposed after opening the front cockpit is minus 17 °C. At this point, the vehicle starts for 3 minutes for preheating. Four minutes after the start of the vehicle, the surface temperature of the driving motor is minus 11 °C, and the surface temperature of the shell(steel) under the 4AT electro-hydraulic driving module is minus 14 °C.

Five minutes after the vehicle was warmed up, the T8A and T5A Super electric trucks conducted calibration tests around the Harbin Third Ring. In order to match the record, T8A carries out rapid acceleration and uniform speed at a speed base of 60 km/h and 40 km/h.

Hydraulic steering power steering machine, test engineering can be controlled single-handed, push-button shift button feedback speed and traditional shift lever automatic transmission shift speed is almost equal. At minus 30 °C, the T8A Super electric truck is activated and can be used for normal garbage transfer (handling top) after the air pressure reaches standard(the power output is 70 % of normal operating conditions).

At minus 18 °C, Preheat for 5 minutes, and the 4AT electrohydraulic drive module can operate at full torque. lithium iron phosphate power cells that are not equipped with water-cooled high-temperature heat dissipation and low-temperature preheating functions will lose some power due to low temperature and will not have key issues such as start-up failure.

6 BYD Electric Heavy Card Drive Bridge

Looking at the pure electric trucks on the market today, in terms of transmission, everyone chooses to cancel the transmission gearbox, or use the AMT gearbox, and even more directly use the traditional manual gearbox. The BYD T8A is completely different. The T8A adopts the electric multi-stage reduction drive axle assembly independently developed by BYD for heavy-duty pure electric trucks. It integrates the motor, gearbox and axle to reduce the intermediate transmission loss and improve efficiency and reliability.

In addition, the electric multi-stage deceleration drive bridge assembly has different speed ratios to adapt to different operating conditions. Low gear can be applied at low speeds to obtain relatively slow speed and stability. When a relatively high speed is required, the gearbox can choose a high-end position and has achieved a faster speed.

At the same time, the driving bridge also uses a wheel side deceleration bridge to further amplify the torque of the motor output. According to BYD, the 4AT gearbox can make up for the loss of speed caused by the large speed ratio of the wheel side deceleration bridge. The 4AT gearbox can reduce the motor load and reduce electricity consumption. Improve battery range.

Suitable for integrated drive bridge with 4AT electro-hydraulic drive module, inter-axle drive motor and inter-wheel differential lock.

BYD T8A fitted 4AT + drive motor + differential lock after the integration of the details of the rear drive bridge close-up. This is also the most technical subsystem of the BYD electric Super truck.

The 4AT electro-hydraulic drive module developed and mass-produced by BYD guarantees more than 80 % transmission efficiency while meeting the large torque transmission.

Among them, the T7 series Super electric trucks are used as vehicles for different models of environmental vehicles, and the 2AT electro-hydraulic drive module and the "integrated" drive bridge of the drive motor(reducer) are fitted. The T8 series Super electric truck is a different model of the vehicle, and it is equipped with a 4AT electro-hydraulic drive module and an "integrated" drive bridge for the drive motor(reducer).

After nearly three years of commercial operation, the "4 1" control module and 4(2) AT electrohydraulic drive module suitable for T7 and T8 Super electric trucks have excellent reliability.

The T8A Super electric truck carries a maximum output power of 180 kW drive motor, which uses the same technical source and reliability as the upcoming second-generation post-Tang drive motor.

BYD's 4AT electro-hydraulic drive module and the "one-dimensional" drive bridge are commercially applied globally to achieve optimal reliability, efficiency, and cost control.

In other words, the T8A vehicle can extend the wheelbase, increase the front and rear drive bridges, and expand to 3 bridges (first 1 after 2) and 4 bridges(first 2 after 2) vehicles. After the expansion, the number of vehicles with different steering bridges and drive bridges can be increased by adapting standardized control modules and configuring 4AT electro-hydraulic driving modules.

The 4AT electro hydraulic drive module that improves the efficiency of electric drive (reduces the cost of electricity use) was introduced, and the cost of the T series Super electric trucks was reduced to a minimum, with the absolute advantage of commercial application of the full life cycle, and commercial vehicles without financial support. The market carried out large-scale commercialization promotion.

The configuration of the double motor +4 AMT transmission can achieve different power output and improve the use economy.

The perfect integration of driving Motors, automatic gearboxes and driving bridges not only makes the vehicle compact, effectively saves space, but also allows the vehicle to drive more smoothly and can greatly improve transmission efficiency.

7 BYD Electric Heavy Card Technology Highlights

Among the many technical highlights, BYD's deep technical heritage is best reflected in the following three points:

Electric Integrated Bridge Assembly Technology

The electric integrated bridge assembly technology equipped with the vehicle is the first in the world and is the top technology that represents the world's pure electric heavy card. It will integrate the drive motor, automatic transmission and drive bridge, compact structure, smoother driving, improve transmission efficiency, and save space.

Six integrated controllers

The vehicle adopts a six-in-one integrated controller, which integrates drive motor control, brake grid-connected feedback, upper-mounted high-voltage power distribution, steering motor power distribution and control, brake air compressor power distribution and control, air-conditioning PTC heater power distribution, and The vehicle's low-voltage power distribution and other functions are integrated, and the power density is high.

power battery and Charging Scheme

The power battery uses a BYD lithium iron phosphate battery. The vehicle is equipped with two power batteries, each with five battery packs located below and behind the cab. The total power is 435 kWh, and the charging time is about 1.5 hours.

The page contains the contents of the machine translation.