Tesla, an American electric vehicle and energy company that produces and sells electric vehicles, solar panels, and energy storage equipment. Palo Alto, based in Silicon Valley, California, was first co-founded in 2003 by MarTInEberhard and Marc Tarpenning, and in 2004 Elon Musk Entered the company and led the A round of financing. The founder named the company "TeslaMotors" to commemorate the physicist Nikola Tesla.
Tesla's first automotive product Roadster was released in 2008 as a two-door sports car. In 2012, Tesla released its second automotive product, the ModelS, a four-door pure electric luxury coupe; the third was a ModelX, a luxury pure electric SUV that was delivered in September 2015. Tesla's next car, the Model3, was first released in March 2016 and will be delivered in late 2017.
Tesla's battery systemThe battery system is the power source for electric vehicles and is the core system component of the entire industry chain. Taking Tesla ModelS as an example, its battery system (lithium battery + battery management system) costs 56%, while the traditional car engine accounts for only 15%-25%. By 2016, the cost of battery systems has decreased, and the cost structure has also changed. The cost of single cells accounts for 83%, the cost of battery management systems accounts for about 13%, and the remaining 4% is battery cooling system. .
By thoroughly combing the composition of the Tesla battery system and the Tesla charging facilities, we can have an intuitive and in-depth understanding of Tesla's battery industry chain, and it can also be used as a bypass for other new energy vehicles. effect. The current cost of the battery system is one of the most important factors restricting the development of Tesla and other new energy vehicles. Understanding the battery system is equivalent to having the key to understanding the new energy automobile industry.
In order to be practical, an electric car must consider its endurance after charging and the convenience of charging. To understand these two points, it is necessary to pay attention to the structure of the battery and the charging speed and device distribution of the charging device.
ModelS has introduced battery power models of 40, 60, 70, 75, 85, 90, 100 kWh. For models of 85 kWh and above, there are also performance versions that offer better power performance, such as Perf and Ludicrous. Version. Different models, the maximum distance traveled and the maximum horsepower are different each time they are fully charged. With the advancement of technology and in order to better meet people's needs, Tesla has successively canceled some ModelS battery models, and the power models that can still be ordered today are 75, 90, 100kWh.
ModelX has introduced 60, 70, 75, 90, 100kWh models, and now only 70 and 100kWh models can be ordered.
According to information from Zhongguancun Online, Tesla's basic version of the Model3 electric vehicle has a battery pack power of about 60 kWh. According to Musk's Twitter and related information, the root Lei Feng network speculated that it may be up to 75kWh. This is mainly due to the smaller wheelbase of the Model3 compared to ModelS and ModelX, and the positioning of the Model3 is also an entry point. According to ElonMusk's July 9th tweet, the first Model3 was rolled out on the same day, and Tesla will hold a delivery ceremony for the first 30 consumers who ordered Model3 on July 28.
In addition, the Model3 battery is also different from ModelS and ModelX. At the media briefing held by Tesla Motors Japan on July 15, 2015, Kurt Kelty, director of battery technology at the US head office, announced that Model 3 will use the new 21700 lithium battery, and its energy density will be better than that for ModelS and ModelX. The 18650 lithium battery is 30% higher.
Unlike other electric vehicles, Tesla uses a battery that is not a dedicated large battery. Instead, it assembles thousands of small cylindrical batteries.
ModelS and ModelX currently use the 18650NCA special battery supplied by Panasonic. This cylindrical battery has a cross-section diameter of 18 mm and a height of 65 mm. The conventional 18650 lithium battery is widely used in the battery of a notebook computer, and its chemical formula is LiNiCoAlO2.
The advantage of using a single battery is that the explosion of a single 18650 battery is limited. Even if one battery unit in parallel fails, the cruising range is shortened by the distance traveled by one battery unit. And this battery is mature and suitable for mass production. At the same time, the battery has good consistency and low cost. Due to the excellent thermal management system of the Tesla electric car itself, Panasonic's 18650 battery made by Tesla has been able to remove some extra safety facilities compared to the conventional one, making it lighter and cheaper. At the same time, Tesla installed a fuse on each cell instead of normally installing a fuse across the battery pack.
Because the power system uses small single cells, Tesla's battery system configuration is extremely complex and ingenious. Taking the ModelS85kWh model as an example, the battery board is divided into 16 battery packs. Each rectangular block shown in the following figure is a battery pack, and two groups are stacked on the far right side. The battery packs are connected in series with a total voltage of 402 volts. Each battery pack of Tesla is made up of 6 single battery packs in series, each battery pack is made up of 74 18650 batteries in parallel. In order to facilitate the placement of the heat dissipation pipes in the battery pack, the single battery packs are arranged irregularly.
Therefore, the ModelS85kWh model uses up to 7104 batteries. Calculated according to the operating voltage of 3.6V and the capacitance of 3.2Ah, the total power is about 82kWh, which is slightly lower than the model. The battery pack consisting of more than 7,000 batteries will weigh nearly 700 kilograms, accounting for nearly half of the weight of the entire car. Similarly, the 100kWh model uses a total of 8256 cells and is equally divided into 16 battery packs.
In order to protect the battery pack, Tesla designed a waterproof and breathable valve on the top surface of the front of the battery pack. The difference between the size of the gas molecules and the liquid and dust particles allowed the gas molecules to pass, and the liquid and dust could not pass. The purpose of waterproofing and venting is to prevent water vapor from condensing inside the battery pack.
The design of the ModelS panel just makes it the bottom plate between the axles. This design brings many benefits. Since the panel is the largest part of the car's weight (the ModelS85kWh battery pack weighs 544 kg), the ModelS has a center of gravity of only 18 inches, so it has a large lateral acceleration (0.9g) and good rollover resistance.
At the same time, in order to protect the battery panel at the bottom, Tesla also added a protective structure made of aluminum alloy (or steel, fiberglass, carbon fiber, plastic, etc., currently used in ModelS). Wrap the battery module and maintain a certain buffer distance and name it BallisTIcShield.
Battery management systemBattery Management System (BMS) is a device for safely monitoring and effectively managing battery packs and improving battery efficiency. Key features include data acquisition, battery status calculation, energy management, thermal management, security management, equalization control, and communication capabilities. Through the system, the effective control of the battery pack charging, discharging and heat release can achieve the purpose of increasing the cruising range, prolonging the service life and reducing the running cost, and ensuring the safety and reliability of the battery pack application.
Tesla's BMS provides accurate battery health prediction technology, battery balance management technology, battery residual power management technology, battery thermal management technology, diagnostic and early warning technology. Even for electric vehicles of the same battery capacity, their cruising range, charging time, start-up acceleration time and battery life will be very different due to different BMS.
With its powerful BMS system, Tesla can effectively achieve consistent management of more than 7,000 18650 batteries for high security and reliability. In addition, in the areas related to BMS related to battery cooling, safety, and charge balance, Tesla has applied for more than 140 core patents, so BMS technology is one of Tesla's core competitiveness.
Each group of Tesla battery packs has its own battery management system located on the side of the battery pack, the green part of the above picture. The sensors and chips monitor the temperature changes of each battery at any time. In case of unexpected situations, the battery can be turned off in milliseconds.
In addition to the battery pack in the panel, the most is the "coolant" line. Each Tesla has a dedicated liquid circulation temperature management system that surrounds each cell.
The "coolant" is green and is a mixture of 50% water and 50% ethylene glycol. The "coolant" constantly flows through the pipe and eventually dissipates in the heat exchanger at the head of the vehicle, thereby maintaining a balanced battery temperature and preventing the battery from degrading due to excessive local temperature. Tesla's battery thermal management system controls the temperature between the battery packs to ±2 °C. Controlling the temperature of the battery panel can effectively extend the battery life.
Supporting charging facilityTesla's charging methods are mainly divided into three ways: home charging, destination charging and super charging station.
Home charging is Tesla's primary charging method. Tesla cars can be charged directly through the 220V10A/16A household outlet. Domestic ordinary household electricity is mostly 220V40A electricity meter, but the socket is mostly 10A or 16A. TESLA with the charging cable with the corresponding plug connection and select 10A or 16A charging current, you can charge without a single meter and any equipment modification, but the charging speed is slow, about 8 kilometers per hour.
Since most of the domestic communities adopt the form of 220V single-phase power supply, the highest current can reach 40A. By installing the home charging pile that comes with each ModelS and ModelX, you can charge it at a charging current of 40A after installing it in your parking space. In this way, the charging speed can be much faster than the charging speed provided by the charging current of most electric vehicles 16A in China.
In addition, you can choose to install the Tesla dedicated charging wall (HighPowerWallConnector). Apply for an 80A meter separately or add an existing meter. Quickly charge by installing a TESLA dedicated charging wall and installing a second charger (in the car, when you need to purchase a car). It can charge up to 17.6kWh per hour and can travel 80-100km. It takes 5-6 hours from no electricity to full power.
Destination charging is a charging method set to facilitate travel. Tesla cooperates to install destination charging stations in some restaurants, restaurants, shopping malls and resorts, and owners can also charge them when they arrive. The charging station at the destination charging station is identical to the charging post or charging wall installed in the home charging. The fee is also determined by the installed company. Tesla's official website shows that it currently has 654 charging stations in 30 provinces (including municipalities and autonomous regions).
In addition to the above two charging methods, Tesla also has a DC fast charging method - super charging. Tesla claims that its super charging station is currently the fastest charging station in the world, charging usually takes only tens of minutes. The location of the charging station is usually located near restaurants, shopping centers, WiFi hotspots, etc., and can be charged during parking breaks. This is the first choice for long-distance travel by car.
According to Tesla's official website data, 861 super charging stations around the world have been established, totaling 5,655 super charging piles. According to Tebola’s official Weibo published in June, 117 super charging stations and 554 super charging piles have been built in China. At the same time, Tesla's global charging network will be doubled in 2017; the expansion of China's charging network will also follow the global expansion rate.
A part of the Tesla Super Charging Station also uses solar panels to provide a portion of the charged electricity, as well as the effect of shading. The cost of each charging pile is between $100,000 and $175,000, and most of the money will be spent on rebuilding the foundation.
Earlier, ElonMusk revealed on Twitter that Tesla will upgrade the Supercharger, and the output power is likely to exceed 350kW, which will undoubtedly further accelerate the charging speed and reduce the charging time.
The charging gun used in the super charging pile is also a highly technically intensive part. When Tesla is charging in the super charging pile, the sensor in the charging gun will always detect the temperature change of the battery inside the car. Once the battery temperature is too high, the charging gun immediately sends a signal to reduce the charging intensity and lower the battery temperature. At the same time, the cooling system in the panel also responds synchronously, so that the cooling force is simultaneously enhanced. This process of automatically adjusting the charging intensity is the current of the electric gun, the battery cooling system, and the charging pile, and works together at a high level.
In addition to Tesla, there are other brands of electric vehicles. They also have their own charging piles. Power companies such as State Grid and China Southern Power Grid have also built some public charging piles. At the Guangzhou Auto Show in November 2016, Tesla officially released the new national standard charging adapter. Since then, Tesla electric vehicles can not only be charged in Tesla's charging network, but also can be charged using a charging facility that complies with China's new national standard.
Plug one end of the adapter into a non-Tesla charging post plug that meets the new national standard and plug it into the Tesla car for charging. However, some charging piles must also be charged with the corresponding charging card, and the charging speed is also uneven.
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