Tesla battery power. How the Tesla Model S battery works

At the end of April, Tesla introduced batteries for the home. What is it: another revolution from an American corporation or a logical link on the way to building a smart and independent home? Let's figure it out together.

Elon Musk can rightly be called a revolutionary in the world of technology. Even 10 years ago, few people believed that electric cars would hit the mass market, and today the Tesla Model S is a sedan that every car enthusiast would want to own. An alternative to the gasoline engine was found a long time ago, but no one dared to “break the whole industry” for a long time.

The issue of production and consumption of electricity in the XXI century is particularly acute. Today, the existence of mankind literally depends on it. The traditional classification of energy production has two global branches:

• mining using commercial sources: coal, oil shale, oil, gas (in fact, they are the basis of modern energy, covering 90% of the total requests from enterprises and the population), nuclear, hydro, geothermal, solar, wave and tidal stations.
• mining from non-commercial sources: agricultural and industrial waste, muscle strength, firewood.

Despite the crisis in fuel resources that made headlines in the early 1970s, almost 50 years later, little has changed in the principles of electricity production. The population is growing, the potential need for electricity is growing, and as a result, the planet is becoming more and more polluted. And one can argue about what will come first - an energy crisis or an environmental catastrophe, but the best way out of this situation is a radical revision of the entire energy industry and the principles of providing the population with electricity.

Tesla Energy and Infrastructure

On April 30, Elon Musk will present a solution that should have a positive impact not only on the environment, but also on consumers' wallets. Tesla Powerwall cares about the environment, drastically reducing carbon dioxide emissions and lets you forget about hefty energy bills. We will deal with the last point a little later, but for now let's look at the world that Tesla offers us.

The idea of ​​energy storage and autonomous provision of houses is not new. Many owners of country cottages have covered the roofs of their homes with solar panels, providing power with lead acid batteries. And here is the first advantage of the Tesla Powerwall.

The number of charge-discharge cycles for a lead-acid battery barely reaches 800, while a lithium-ion battery boasts 1000-1200 cycles. In terms of weight-to-capacity ratio, a lithium-ion battery is almost 5 times superior to a lead-acid battery. This is what allowed Tesla to create a catchy design for its new product line.

Design and form factor. Yes, a person's opinion about any product is formed by its appearance. Rounded edges, the minimum thickness (by the standards of competing products) of the body, the presence of an assortment of colors. Even without delving into the principles of the Tesla Powerwall, you start thinking about how it would complement your garage. Tesla Powerwall is mounted on the wall and takes up a minimum of space.

Holistic Ecosystem. The presented Tesla Powerwall batteries are supplied in two versions with a capacity of 7 and 10 kWh at a price of $3000 And $3500 respectively. If the consumer feels a clear lack of capacity, he can always supplement the arsenal of batteries by purchasing another one, thereby increasing the total capacity up to 90 kWh (up to 9 batteries can be connected). Connection does not require a thorough study of the principles of building electrical networks: one cable solves all problems.

Solution for enterprises and businesses. Together with Powerwall, a product was also presented that can solve the problem of supplying factories, factories and the whole industry - batteries Tesla power pack. Their feature is the ability to infinitely increase the potential capacity up to several Gigawatts * h.

Plans for full alternative electrification. Elon Musk is a person who is used to thinking globally. That is why the presentation of Tesla batteries does not have the sole purpose of selling the product to a limited circle of interested users. We are talking about large-scale and total electrification of the entire planet Earth with the help of batteries. To provide the entire planet with enough Tesla energy 900 million powerpack batteries.

Caring for the environment, a complete rejection of the production of electricity, the source of which will be exhaustible natural resources leading to the release of harmful substances into the atmosphere and the complete autonomy of any, even the most remote corner of the planet - all these are the realities of today. But until there is (if any) a global transition to electricity drawn from the sun, wind, tides and stored in batteries, a potential buyer is interested in the question: is Tesla Powerwall profitable today?

Dry numbers

So, let's calculate the economic feasibility of purchasing an innovative product from Tesla. Is the game worth the candle and how will the payback behave in the conditions of Russia and the USA.

Payment terms:

• let's take the daily electricity consumption of the Tesla Powerwall owner equal to 10 kW, i.e. the full capacity of the battery is enough for a day of consumption;
• Tesla Powerwall cost - $3 500 , which at the exchange rate current at the time of publication of these calculations is 175 000 rubles(taking into account rounding and at the rate of 50.01 rubles per $1);
• to the cost of Tesla Powerwall we add the need to purchase an inverter, the cost of which is about $ 1,500 - 75,000 rubles;
• take into account losses when connecting Tesla Powerwall in the chain battery - current converter - inverter. General System efficiency will be 87%. Those. Initially, not 10 kWh, but only 8.7 are available to the consumer.
• with two-zone billing (“day/night” rates), we will take daily energy consumption at the level of 5 kWh (57.5% of the maximum Tesla Powerwall resource), and evening energy consumption at the level of 3.7 kWh (42.5%) .

The situation in the USA:

Valid in the USA two-zone tariff for electricity bills:

From 14:00 to 19:00 the cost of 1 kWh of electricity is $0.2032 (10.16 rubles).
From 19:00 to 14:00 the cost drops sharply to $0.0463 (2.31 rubles) per 1 kWh.

With a consumption of 5 kWh in the daytime and 3.7 kWh in the "night" time, the daily costs using a standard power grid will be:

5 kW * h * 10.16 rubles + 3.7 kW * h * 2.31 rubles = 50.82 rubles + 8.54 rubles = 59.36 rubles / day.
59.34 rubles * 365 days = 21,659 rubles per year.

A standard lithium-ion battery loses about 6% (0.6 kW) of its original capacity (i.e. 10 kW) per year. Every year its capacity will decrease and after 3-4 years only one Tesla Powerwall will not be enough. Here are rough calculations of how the battery will behave over time.

Years of operation: The maximum battery life is 15 years.
Maximum capacity: decreases by 6% (0.6 kW) of the original capacity every year.
Electricity cost: calculated from the ratio of day / night rates at the prices indicated above.
Saving: how much Tesla Powerwall saves per year.
Spending on additional energy: we agreed that we consume 8.7 kW per day. The missing electricity (caused by the degradation of the battery) is compensated by the public electricity network.

Over 15 years of use, even without taking into account the waste of additional energy, Tesla Powerwall not paying off. Considering that the cost of a kWh of electricity in Russia is about 60% lower, it is hardly worth talking about the expediency of such an acquisition. Let me remind you that the purchase of the Tesla Powerwall kit cost 250,000 rubles, and this does not include solar panels.

Reflections

Tesla's self-sustaining solution is the right way to look to a future without emissions and ruthless use of natural resources. Alas, for the end consumer, the cost declared on the Tesla Powerwall will not be an economically advantageous acquisition. To buy a battery, you will need to add the “price of incense and candles” in the form of solar panels, a converter and an inverter, and the degradation of lithium-ion batteries is simply will not cover the initial costs. But if you are ready to invest in the future, ready to take a step towards the "green planet" and the price of the issue is not decisive - the time for Tesla Powerwall has already come for you.

And do not forget that the disposal of any battery also costs money. Sometimes a lot.

We partially reviewed the configuration of the battery Tesla Model S with a capacity of 85 kWh. Recall that the main element of the battery is a lithium-ion battery cell of the company Panasonic, 3400 mAh, 3.7 V.

Panasonic cell, size 18650

The figure shows a typical cell. In reality, the cells in Tesla are slightly modified.

Cell Data parallel join in groups of 74 pcs. When connected in parallel, the voltage of the group is equal to the voltage of each of the elements (4.2 V), and the capacitance of the group is equal to the sum of the capacitances of the elements (250 Ah).

Further six groups connect in series to the module. In this case, the voltage of the module is summed from the voltages of the groups and equals approximately 25 V (4.2 V * 6 groups). The capacity remains 250 Ah. Finally, modules are connected in series to form a battery. In total, the battery contains 16 modules (total 96 groups). The voltage of all modules is summed up and totals 400 V (16 modules * 25 V).

The load for this battery is an asynchronous electric drive with a maximum power of 310 kW. Since P = U * I, in the nominal mode at a voltage of 400 V, the current I = P / U = 310000/400 = 775 A flows in the circuit. At first glance, it may seem that this is a crazy current for such a “battery”. However, do not forget that with a parallel connection according to the first Kirchhoff law, I = I1 + I2 + ... In, where n is the number of parallel branches. In our case, n=74. Since we consider the internal resistances of the cells within the group to be conditionally equal, then the currents in them will be the same. Accordingly, a current flows directly through the cell In=I/n=775/74=10.5 A.

Is it a lot or a little? Good or bad? In order to answer these questions, let us turn to the discharge characteristic of a lithium-ion battery. American craftsmen, having disassembled the battery, conducted a series of tests. In particular, the figure shows voltage oscillograms during the discharge of a cell taken from a real Tesla Model S, currents: 1A, 3A, 10A.

The spike on the 10A curve is due to manual switching of the load to 3A. The author of the experiment was solving another problem in parallel, we will not dwell on it.

As can be seen from the figure, a discharge with a current of 10 A fully satisfies the requirements for cell voltage. This mode corresponds to the discharge according to the 3C curve. It should be noted that we took the most critical case, when the engine power is maximum. In reality, taking into account the very use of a two-motor drive with an optimal gear ratio, the car will operate with a discharge of 2 ... 4 A (1C). Only at moments of very sharp acceleration, when driving uphill at high speed, the cell current can reach a peak of 12 ... 14 A.

What other benefits does it provide? For this load in the case of direct current, the cross section of the copper conductor can be selected as 2 mm2. Tesla Motors kills two birds with one stone here. All connecting conductors also perform the function of fuses. Accordingly, there is no need to use an expensive protection system, additionally use fuses. The connecting conductors themselves in the event of an overcurrent due to the small cross section melt and prevent an emergency. We wrote more about this.

In the figure, the conductors 507 are the same connectors.

Finally, let's consider the last question that worries the minds of our time, and causes a wave of controversy. Why does Tesla use lithium-ion batteries?

Immediately make a reservation that specifically in this matter I will express my own, subjective opinion. You may not agree with him.)

We will conduct a comparative analysis of different types of batteries.

Obviously, the lithium-ion battery has by far the highest specific performance. The best battery in terms of energy density and mass / size ratio, alas, does not yet exist in mass production. That is why in Tesla it turned out to make such a balanced battery, providing a power reserve of up to 500 km.

The second reason, in my opinion, is marketing. All the same, on average, the resource of such cells is about 500 charge-discharge cycles. And this means that with active use of the car, you will have to replace the battery after a maximum of two years. Although, the company really

The Tesla battery is world famous for its breakthrough in electric vehicles. The idea is not new and has been mastered for many years by leading automotive companies. However, American designers were able to optimize this direction, taking into account the interests of the consumer. To a large extent, this has become possible due to innovative power supply systems focused on the complete replacement of conventional internal combustion engines. Consider the features and varieties of this drive.

Application

The development of fundamentally new types of li-ion batteries is due to the tasks of improving the performance of electric cars. In this regard, the basic line of the Tesla S model is focused on providing the vehicle with innovative power sources. A feature of lithium-ion batteries was the introduction of a combined mode of operation, in which the alternation of energy supply from an internal combustion engine and AB is allowed. At the same time, the company's engineers continue to develop machines that are completely independent of the usual type of fuel.

It is worth noting that engineers are not limited solely to the creation of power elements for road transport. Several versions of Tesla batteries have already been released for domestic and commercial use. If the option for an electric car is aimed at maintaining the operation of running gear and on-board electronics, then stationary storage modifications are positioned as autonomous sources of electricity. The capabilities of these elements make it possible to use them for servicing home appliances. Additionally, research is underway on the accumulation of solar energy. Works are still at the development stage.

Device

Tesla batteries have a unique structure and way of placing active components. The main difference from the analogue is the lithium-ion configuration. Similar elements are used in the design of mobile devices and electric tools. Tesla engineers first used them as batteries for cars. The whole block is divided into 74 compartments, which look like AA batteries. Depending on the configuration of the battery, it includes from 6 to 16 segments in the design. The positive charge comes from the graphite electrode, the negative moment comes from several chemical components, including nickel, cobalt, and alumina.

Tesla batteries are integrated into the car by fixing them on the bottom of the vehicle. This arrangement provides a low center of gravity of the electric vehicle, improving handling. Special brackets are used as fasteners. Currently, there are not many such solutions, therefore, this part is often compared with a traditional battery.

Important points relate to security and placement. The first factor is guaranteed by the high-strength housing in which the battery is mounted. In addition, each block is equipped with a fence in the form of metal plates. In this case, not the entire internal part is isolated, but each element separately. It should also be noted that there is a plastic lining that prevents water from getting inside.

1. Converter.
2. High voltage wiring.
3. Main charger.
4. Additional charge.
5. connector.
6. Module.

Characteristics of the Tesla battery

The most powerful variation of the battery for an electric car consists of 7104 small batteries. Below are the parameters of the specified element:

• Length / thickness / width - 2100/150/1500 mm.
• The electrical voltage indicator is 3.6 V.
• The amount of power generated by one section is identical to the potential performance of a hundred personal computers.
• The weight of Tesla batteries is 540 kg.
• The travel time on one charge on an average element with a power of 85 kW / h is about 400 km.
• Acceleration up to 100 km / h - 4.4 seconds.

With these characteristics, a reasonable question arises as to how durable these structures are, because high performance implies intensive wear of active parts. It should be noted that the manufacturer gives an eight-year warranty for its products. Most likely, the working life of the ABs under consideration will be the same.

So far, the owners of electric cars cannot confirm or deny this fact. In addition, there are research results that indicate that the battery power parameter is characterized by its moderate loss. On average, this figure is about 5% per 80 thousand kilometers. There are other facts that indicate that the owners of the specified vehicle regarding problems in the battery compartment are turning less and less as new models are released.

Tesla Battery Capacity (Model S)

It is necessary to evaluate the capacitive characteristic of batteries taking into account the development of production. During the improvement of the line, the indicator varied from 60 to 105 kW / h. Official information indicates that the peak battery capacity is about 100 kW / h. According to the reviews of the owners, the real parameter will be somewhat lower. For example, an 85 kW Tesla battery actually produces no more than 77 kW.

In history, there are also reverse examples confirming the excess of the volume. There are cases when a 100-kilowatt battery was endowed with a capacity of about 102 kW. From time to time, contradictions are found in the definition of active nutritional components. Mostly, discrepancies are observed in estimates of the number of block cells. This is due to the fact that the battery is constantly being upgraded and refined, equipped with innovative elements.

The manufacturer claims that every year updated modifications undergo transformations in electronic parts, cooling system, and architecture. The ultimate task of designers is to achieve the highest possible quality characteristics of the product.

Power Wall version

As mentioned earlier, along with the release of Tesla car batteries, the company produces household versions of energy storage devices. One of the productive and latest modifications was the lithium-ion version of the Power Wall. It is designed to generate energy as a permanent source or is operated as a standby structure similar to an autonomous generator. The model is presented in several variations, differing in capacity and serving to perform certain energy tasks. The most popular versions are 7 and 10 kWh units.

Regarding the operational parameters, it can be noted that Power Wall has a power of 3.3 kW with an operating voltage of 350-450 watts, a current of 9 A. The weight of the structure is 100 kilograms, therefore, its mobility is out of the question. However, as an option, for example, for summer cottages, the block is quite suitable. The unit is transported without problems, since the designers pay great attention to the mechanical protection of the body part. Certain disadvantages include a long battery charging period (12-18 hours), depending on the modification of the drive.

Model "Power Pack" (Power Pack)

This system is based on the previous version, but is focused on commercial purposes. This means that such a Tesla battery is used to service enterprises. It is a scalable energy storage device that provides increased system performance at the target site. It should be noted that the battery capacity is 100 kW, while the indicated capacity does not apply to the maximum indicator. Engineers have provided a flexible design for the aggregation of several units with the possibility of obtaining a value from 500 kW to 10 MW.

Single modifications are also being upgraded in terms of quality of operation. Official information has already been received about the appearance of the second generation of commercial batteries, in which the power parameter was 200 kW, and the efficiency approached 99%. The specified energy storage device differs in technological indicators. To expand the volume, the developers used a reversible inverter.

This innovation made it possible to increase both the power and performance of the system. The company plans to develop and implement Power Pack cells in the design of additional solar components such as Solar Roof. This approach allows you to renew the energy potential of the battery not through special lines, but through a free solar stream in a continuous mode.

Production capacity

According to the manufacturer himself, innovative batteries are manufactured at Tesla's own Gigafactory. The assembly procedure was organized with the participation of Panasonic representatives (delivery of components for block segments). The specified enterprise produces the latest designs of power systems focused on the third generation of Model electric cars.

It is assumed that the total number of manufactured products in the limiting production cycle will be up to 35 GW / h. It is worth emphasizing that the indicated volume is half of all the parameters of batteries produced in the world. Current maintenance is carried out by a team of 6.5 thousand people. In the future, it is planned to create an additional 20,000 jobs.

Among the features, a high degree of protection against hacking of the battery is noted. This eliminates the possible risks of filling the market with counterfeit variations. In addition, the production procedure itself involves the participation of high-precision robotic technology in the process. There is no doubt that only corporations of the Tesla level are able to display all the technological production nuances at the present time. Most interested organizations do not need plagiarism, since they are actively developing their own developments.

Price policy

The cost of the Tesla battery is also constantly changing due to cheaper production technologies and due to the release of updated components with increased performance parameters. Two or three years ago, the type of accumulative device under consideration was sold within 45 thousand dollars (about 3 million rubles). Now the blocks have a price of about five thousand dollars (330,000 rubles).

Approximately the same cost for home analogues of the Power Wall configuration. The most expensive versions include a commercial battery. For example, the first generation of the specified device can be purchased for $ 20-25,000 (approximately 1,327,000 - 1,650,000 rubles).

Competing modifications

The Tesla company is not a monopolist in the production of li-ion batteries. Despite the fact that other brands are not so well known on the market, their parameters are quite competitive. Among the popular representatives:

• The Korean corporation LG produces Chem Resu drives, which are analogues of the Tesla PowerWall (a 6.5 kW / h system costs about 4 thousand dollars or 265,000 rubles).
• The product from Sunverge has a power range from 6 to 23 kW / h, is distinguished by the ability to monitor the charge and connect to solar panels (the price is 10-20 thousand dollars or 665,000 - 1,327,000 rubles).
• ElectrIQ sells household storage batteries with a capacity of 10 kW / h (together with the inverter, the product will cost $ 13,000 or 865,000 rubles).
• Among automotive competitors, firms such as Nissan and Mercedes stand out.

The first auto giant produces a series of XStorage batteries (working volume - 4.2 kW / h). The nuances of this modification include a high level of environmental safety, which fully complies with international standards for the production of passenger cars. Mercedes produces compact versions of 2.5 kW / h. At the same time, they can be combined into increased productive systems with a capacity of 20 kW / h.

Peculiarities

Tesla electric car batteries and their household counterparts are not very affordable for the mass consumer. With Power Wall systems, the situation is somewhat changing due to cheaper components. But the idea of ​​aggregation with blocks of solar panels cannot yet be successfully implemented due to the high cost. Undoubtedly, the possibility of accumulating a free energy source is beneficial for consumers, but the purchase of such structures is beyond the reach of most interested users.

A similar story is with other alternative drives, the principle of operation and the use of which gives a lot of advantages, but requires the use of high-tech devices and devices.

Outcome

In the battery market for electric vehicles, Tesla is the undisputed leader. This is largely due to the use of innovative equipment in the production of environmentally friendly transport. At the same time, the engineers of the leading company face certain obstacles. For example, the Model S series with lithium-ion cells is criticized for poor protection against the ignition of power cells.

However, designers are constantly improving their models and treat criticism constructively. For example, after the only AB fire in the history of electric vehicles, cars began to install a hollow aluminum beam (to protect against obstacles on the road surface), a shield made of pressed aluminum and a titanium plate. Everyone who bought cars before this improvement is offered to complete them free of charge at service stations.

The loss of battery capacity during operation is one of the problems of electric vehicles, despite the fact that this process is the norm for any devices equipped with lithium-ion batteries. However, Plug-in America experts have found that the electric car is an exception in this regard.

Yes, they did independent study, which showed that the loss of power in the Model S battery even during long runs is small. In particular, the battery pack of this car loses an average of 5% of its power after overcoming the mark of 50,000 miles (80,000 km), and with a run of more than 100,000 miles (160,000 km), less than 8% at all . The study was conducted on the basis of data from 500 Tesla Model S electric cars, the total range of which was more than 12 million miles (20 million km).

In addition, Plug-in America conducted another study that showed that in the four years (since the introduction of the Tesla Model S to the market), the number of calls to Tesla service stations due to problems with the battery, electric motor or charger has been significantly reduced. device.

The capacity of a battery may depend on several factors such as how often the capacity is fully charged, periods of time spent in an uncharged state, and the number of quick charges. Plugin America data also shows that replacement rates for major components have improved significantly:

Such data is encouraging, but despite this, Tesla continues to work on improving its battery and cell technology. The company began a scientific collaboration with the Jeff Dahn Research Group at Dalhousie University. This department specializes in extending the life of Li-ion battery cells, and its goal is to maximize battery life with little power loss.

Note that the Tesla Model S battery, as well as the car itself since 2014, has a guarantee for a period of 8 years and without mileage restrictions. Then the head of Tesla, Elon Musk, explained the decision as follows: “If we really believe that electric motors are much more reliable than internal combustion engines, with fewer moving parts ... then our warranty policy should reflect this.”

Let's look inside the Tesla Model S electric car battery and find out how it works.

According to the North American Environmental Protection Agency (EPA), the Model S needs a single charge of 85 kWh batteries to cover more than 400 km, which is the most significant indicator among similar cars on the specialized market. To accelerate to 100 km / h, the electric car needs only 4.4 seconds.

The key to the success of this model is the presence of lithium-ion batteries, the main components of which are supplied to Tesla by Panasonic. Tesla batteries are covered in legends. And so one of the owners of such a battery decided to violate its integrity and find out what it is like inside. By the way, the cost of such a battery is 45,000 USD.

The battery is located at the bottom, thanks to which Tesla has a low center of gravity and excellent handling. It is attached to the body by means of brackets.

Parsing:

The battery compartment is formed by 16 blocks, which are connected in parallel and protected from the environment by means of metal plates, as well as a plastic lining that prevents water from entering.

Before completely disassembling it, the electrical voltage was measured, which confirmed the working condition of the battery.

The assembly of batteries is characterized by high density and precision fitting of parts. The entire picking process takes place in a completely sterile room, using robots.

Each block consists of 74 elements, which are very similar in appearance to simple finger batteries (Panasonic lithium-ion cells), divided into 6 groups. At the same time, it is almost impossible to find out the scheme of their placement and operation - this is a big secret, which means that it will be extremely difficult to make a replica of this battery. We are unlikely to see a Chinese analogue of the Tesla Model S battery.

The positive electrode is graphite, and the negative electrode is nickel, cobalt and aluminum oxide. The specified amount of electrical voltage in the capsule is 3.6V.

The most powerful battery available (its volume is 85 kWh) consists of 7104 such batteries. And it weighs about 540 kg, and its parameters are 210 cm long, 150 cm wide and 15 cm thick. The amount of energy generated by just one unit of 16 is equal to the amount produced by a hundred batteries from laptop computers.

When assembling their batteries, Tesla uses elements produced in various countries, such as India, China, Mexico, but the final refinement and packaging are made in the United States. The company provides warranty service for its products for up to 8 years.

Now you know what the Tesla Model S electric car battery consists of.