Batteries For Inverter Calculation

To illustrate further, suppose you bought a W inverter with a 12V input. If you use the inverter’s full capacity, that is 416 amps an hour. (W / 12V = 416). Theoretically a 450-500ah battery can run the system for an hour. But inverters are not perfect and some energy is lost, so more likely it is 30-45 minutes. Of course the figure will be different if you have a 24V, 36V or 48V battery.

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However that figure supposes you will run the battery down to zero, or a 100% discharge. We have stated in other posts on this site that lead acid batteries should be recharged at 50%. So you need at least a 750ah-800A battery to run the inverter for 30-45 minutes without totally depleting the battery.

No matter what the voltage is, the ah rating in series configured batteries will always be that of the smallest battery in the setup. Multiple batteries increases voltage so the power supplied (in watts) increases.

With four 210ah 48V batteries, the inverter receives 104ah hourly. With a full discharge the inverter can run at maximum load for two hours or 10kwh (10,000W). Bottom line: no matter what the battery bank voltage, it must provide W for every hour you want the inverter to operate.

1. Add Your Total Load Requirements

W is a lot of power but do you really need that inverter size? The best way to find out is to add up the total watt usage of all your loads. Include every appliance and device you plan to run on the inverter. Do note that refrigerators and air conditioners have surge requirements so a large system is definitely required.

2. Check The Inverter Input Voltage

A lot of inverters have 12V or 24V input, but 36V, 48V and even 96V and others are not uncommon. Make sure your battery matches the input. The battery doesn’t have to be a specific match as long as the total is the same. Example, a 48V inverter will work with a 12V battery if you have four hooked up (12 x 4 = 48).

3. Determine How Many Hours You Need To Run The Inverter

This is crucial. How long do you plan to run the inverter? Is it for a couple of hours? 5 hours? 12 hours or more? This tells you how many watt hours you need and how much the battery capacity has to be.

Suppose your W, 48V inverter needs to run for 6 hours. If the power load factor is 0.8 then the volt amperes (VA) is 130 amperes. Your battery must be able to provide minimum 130 amperes. 48V 130 ampere batteries are uncommon so you may opt for a 200 amperes instead.

4. Calculate Battery Storage Capacity

Battery capacity is measured in amp hours (ah). With our example here you need four 200ah-220ah batteries. That should be sufficient to run a W inverter for 8 hours more or less.

These steps are best suited for homes that need a large power backup. For RVs, the needs are usually smaller and the calculations more straightforward.

Lithium Polymer batteries popularly referred to as LiPo is now gaining massive popularity. Now everyone that needs high and long-run power wants to use lithium Polymer. But do they understand how it works? Very few people do. As long as you follow instructions and treat them well, they will serve you for a long time.

The main benefits for lipo batteries are; Light, higher capacity, and discharge rates. Since nothing is perfect, they have some drawbacks as well. For example, they have a much shorter lifespan and also need a lot of care and attention. Many, lithium polymer batteries contain a plastic pouch known as a pouch cell. They are very efficient for building multi-celled packs.

Pouch cells hold all the cells firmly without leaving any airspaces like in the round packed battery cells. Besides, the pouch cell is lighter compared to metal cans hence making them the most preferred for aircraft applications. By contrast, lithium-ion cells are heavier by 20% more than regular lipo pouch cells.

LiPo pouch cells allow more gassing and thermal expansion due to its flexible pouch casing. Furthermore, inside when you open the cell, you will find a polymer, which is a thin plastic microporous film. It is located within the copper anode, cathode electrodes, and lithium coat aluminum. However, they are all laminated, alternating each other from the back and the front side of the polymer separator film.

The long film, which sometimes can be over seven feet long, is folded in an alternating cathode/anode stacking. Also, a thin continuous layer of polymer separator is inserted to separate them. If you lipo cell leaks at any given time, please do not use it. The pouch is pressed under some pressure before the final heating and sealing. That helps to remove the air that is remaining inside before its ready to be used.

How long it will take for me to charge a car battery at 50 amps.

This a friend asked before. And later there are some other customer ask for some similar question like: How long to charge a car battery at 40 amps. Of cause, there will be some more ask 30amps or 60amps.

Here Let me simply anwser this question here.

When we talke about car battery. It is normally a lead acid battery inside of the car. And a normal one is about 70amp hour or 60ah. Let’s say, if the battery can take as much as 50 amps current. Based on the calculation, we understand, it will be fully charged by 1 hour more.  But from acture operation, this could be much more then 1 hour. Or maybe 2 hours. We know the battery start charge will accept the peak current. later, when the battery voltage goes up, the charging current will slow down. We call it floating charge. During floating charge, you will not possible to load the large current. That’s why it will takes much longer based on your battery.

Learn how to charge the battery

This is a sad question when people ask.

When you try to charge your car battery. Means your car battery is almost dead. If you have time to learn how long it takes to charge the battery at some current( 40 or 50 amps.). why not just think how to find a new one for replace. Or maybe you will stuck on the road most probebely , and you don’t know when that’s will comes to you.

Think about a LiFePo4 battery to replace the lead acid car battery?

Let’s check if CMX can provide such a battery or not?

How To Tell If A Deep Cycle lithium ion Battery Is Bad

Deep cycle lithium-ion batteries are normally serving for marine, Recreational Vehicle (RV), solar energy power, and similar applications. These battery packs normally made by cells or some other lithium prismatic cells. They are different from your lead acid car starting batteries. Analyzing cells inside a battery pack takes a sophisticated set of measurements against certain exact parameters. To know the battery state and make sure it working in good conditions. You should know how to determine if it is bad or not. Here are some basic points you can check if the battery bad or still possible to serving.

Find out Factory Datasheet:

Check out what kind of lithium battery it is and try to find manufacturer specs datasheet. And find out what exactly the battery should behave about voltage limits, current, internal resistance etc.

Check if cell characteristic Meet

Use proper tools like multimeter, try to measure voltage, resistance and performance. Compare these values with manufacturer datasheet specifications. Match it? Or it is far away? Simple as that.

• Specifications Meet: If you measuring match more or less what manufacturer saying, it should be ok.
• Not meet the specifications – well, probably it is safer to discard such battery. No worth for risk fire or anything such.

In case if manufacturer data are not available, then try to find out what kind of lithium battery (cell) it is and upon that measure it. There are

many different types:

Most common lithium rechargeable batteries are

• li-ion with nominal voltage 3.6V or 3.7 volt Most of them , and some prismatic lithium NCM batteries.
• lifepo4 with 3.2V. Same as above. Mostly are large lithium cells
• LTO with 2.4V

The easier way how to find whether lithium battery is bad or not

Try to charge it to full SoC (near 100%) and then measure voltage drop when discharge.

Example: battery cells with rated capacity mAh have nominal voltage 3.6V, full charge 4.2V and cut-off discharge limit 2.75V. Charge to somewhere around 4.1–4.2V and then start discharge with 1A current. In that moment measure voltage drop. It should not go below 4V at all. If it going much below, like 3.9, 3.8 or lower, the cell is very old and ready to bin.

Check Cell Temp

Also, if such cell (as mentioned above) heating too much when charging/discharging by 1A, it is again not safe to use it anymore and better to discard it.

Voltage Drops rate

Self-discharge speed can tell you, whether cell is good or bad. Charge it fully and place somewhere safely. Read voltage after few hours. note it. After one month (or even two), measure voltage again. Should not be different from first measure more than 10% of total value. If it’s more, cell is poor/bad.

Caution:

This is not for the novice as there can be fire involved if you do test wrong. As a cursory test leave the battery or cell in the device it was designed for and run the device. If it does not run full speed or at all put the charger that was designed for that device on and wait the appropriate amount of time. All the engineering needed to safely cycle that battery or cell is in the charger and in the device that used that cell or battery. A voltage check is good for a quick screen but voltage alone does not give enough information. Testing under a load can again create fire so don’t just start adding load randomly. Our system does not require the user have anything to do with battery anything. Every part of energy delivery is hands-off automatic so the user does not need to know what charging method or voltage or current to memorize. They just drive with unlimited miles on a monthly subscription. All battery failures or maintenance is hidden completely and super accurate to keep everyone moving. End of life is contained by us so you do not need to replace anything or test for failures. We recycle every metal inside those cells where some on this question mention throwing them away which is unwise in the bigger picture. If the cell is pouched out it is BAD. If the terminal wire is burned in two in a large pack that cell is bad. That burned link is a fuse and was burned in two on purpose. The cell below it is bad. Do not try to solder over the open circuit link.

Step 1. Check the connections.
It may seem improbable, but the stability of any power connection is limited by its weakest link. Check the contacts and terminals for dirt, oils, corrosion, excessive wear or anything that can hamper a good, stable connection. This includes the battery contacts with application, in the charger, and on the battery itself.

Step 2. Reseat the battery in the devices.
It seems unlikely, but it happens. Some application require a tight fit with the battery and may seem attached when they are not fully locked in place. Make sure the battery is seated properly and the battery pack locks firmly in place when attaching it.

Step 3. Verify you are using the correct battery charger.
Using the wrong charger can not only prevent your  battery from charging properly, it could damage your equipment. It can also be potentially dangerous.

Step 4. Check to be sure the charger is plugged in and turned on.
Sound silly, doesn’t it? Well, it isn’t really, because it does happen. It’s one of the easiest mistakes to make when charging a fleet of batteries and one of the simplest to resolve.

Step 5. Reseat the  battery in the charger.
Battery seems like it’s connected to the charger when it’s not making contact at all. If it is a drop-in or desktop charger with a pocket or tray, the radio and/or battery may be able to sit in the tray without actually touching the contacts. If it is a plug-in type of charger, the plug may not be fully inserted. Be sure the radio/battery is properly seated or fully connected and the charging indicator light is on.

Step 6. Charge another battery of the same make and model in the charger.
Determine if the issue is really with the battery pack.

Step 7. Swap out the charger.
Sometimes a dead battery is the result of a dead charger.

Step 8. Charge the battery again.
Just to be sure, give it another chance.

Every battery has a limited life span determined by a number of different factors, including but not limited to how and where it is used, how much it is used and under what conditions. There is no set time table before a battery “kicks the bucket”. If your battery has reached its End of Life, it’s time to purchase a new one.

First, the production cost of lithium batteries is high, the production equipment is expensive, the labor cost accounts for about 40% of the production cost, and the price is about three times that of lead-acid batteries. The triple price of lithium batteries brings about low cost performance, fairly smooth feeling, and it is difficult to recycle lithium batteries, and the utilization rate is not high. Due to the small size of lithium batteries, multiple lithium batteries are connected in series during the assembly process, which may lead to the disconnection or welding of a solder joint during transportation and use, which is a common problem in the connection of lithium batteries.

Secondly, the high current discharge characteristic of lithium ion power supply itself is short plate. Considering the frequent start-up of congested roads, the battery life will be greatly shortened. Lithium batteries have potential safety hazards of fire and explosion. Nobody wants to buy a “time bomb” and put it under his body. Especially when consumers do not know the fact that they have purchased some inferior lithium batteries online, the sealing condition of electric vehicles is not very good, and it is easy to cause unsafe contact due to dampness and other reasons. Some people may say that lithium battery technology is developing very fast, there will be no such problem, but no one can guarantee that this problem will not happen.

Thirdly, compared with lead-acid batteries, lithium batteries have the same weight and volume. The capacity of lithium batteries is generally about three times that of lead-acid batteries. However, for electric vehicles as alternative tools, the effect is actually limited, because many lead-acid batteries also greatly improve their endurance, which reduces the gap between lithium batteries and lead-acid batteries.

4. If lithium batteries are used instead of lead-acid batteries, it must also be considered that the voltage of lithium batteries must be the same as that of original lead-acid batteries. In addition, a special lithium charger must be replaced. Of course, there is another problem. If the lithium battery is improperly installed or has quality problems, the controller may burn out, which is one of the reasons why the installation is not recommended.

Fifth, coupled with the promulgation of the new national standards, speed limits of 25 km/h and other provisions, consumers will not be too harsh on the pursuit of electric vehicles, so that consumers spend several times the money to pay, I believe that not many people will be willing. The price of lithium batteries is several times higher than that of lead-acid batteries, reflecting the low price ratio of lithium batteries, which does not meet the standard for ordinary users to choose electric vehicles. Although lithium batteries have the characteristics of light weight, long life and long service life, the effect is not obvious in actual operation. To replace lead-acid batteries with lithium batteries, we must also consider the size of the battery bunker. Generally speaking, lead-acid batteries are larger and lithium batteries are smaller. If you want to replace them, you must take this into account. If the gap after installation is too large, it is easy to cause small shaking inside the battery and reduce its life.

6. Lithium batteries are more stable than lead-acid batteries. If they are exposed to water or improperly treated, they can easily explode. Therefore, this is an important reason why I do not recommend replacing lead-acid batteries with lithium batteries. Another point to note is that lithium batteries are multi-piece structure, as long as there are problems, it will affect the overall quality.

Want more information on wholesale lifepo4 cylindrical cells for RV and marine use? Feel free to contact us.

In short, lithium batteries are not conducive to their promotion, regardless of safety or cost. As far as current technology is concerned, lead-acid batteries are still the main ones. Want to replace lead-acid electric cars with lithium batteries? In addition to safety, when implementing the new national standards, modifications may be defined as vehicles exceeding the standards. If you are really interested in lithium batteries, it is recommended to buy lithium trams that meet national standards.

It is hard to determin the exact capacity of the battery cell after it is produced from a lithium battery factory, and this is especially true with lead acid and other batteries that involve manual assembly. Even fully automated cell production in clean rooms causes performance differences. As part of quality control, each cell is measured and segregated into categories according to their capacity levels. The high-capacity NiMH and other cells may be reserved for special applications and sold at premium prices; the large mid-range will go to commercial and industrial markets; and the low-grade cells might end up in a consumer product or in a department store. Cycling will not significantly improve the capacity of the low-end cell, and the buyer should be aware of differences in capacity and quality, which often translate into life expectancy.

Cell matching according to capacity is important, especially for industrial batteries, and no perfect match is possible. If slightly off, nickel-based cells adapt to each other after a few charge/discharge cycles similar to the players on a winning sports team. High-quality cells continue to perform longer than the lower-quality counterparts, and fading is more even and controlled. Lower-grade cells, on the other hand, diverge more quickly with use and time, and failures due to cell mismatch are more widespread. Cell mismatch is a common cause of failure in industrial batteries. Manufacturers of professional power tools and medical equipment are careful with the choice of cells to attain good battery reliability and long life.

Let’s look at what happens to a weak cell that is strung together with stronger cells in a pack. The weak cell holds less capacity and is discharged more quickly than their strong brothers. Going empty first causes their strong brothers to overrun their feeble sibling to the point where a high load can push the weak cell into reverse polarity. Nickel-cadmium can tolerate a reverse voltage of minus 0.2V at a few milliamps, but exceeding this will cause a permanent electrical short. On charge, the weak cell reaches full charge first, and then goes into heat-generating overcharge, while the strong brothers still accept charge and stay cool. The weak cell experiences a disadvantage on both charge and discharge; it continues to weaken until giving up the struggle.

The capacity tolerance between cells in an industrial battery should be +/– 2.5 percent. High-voltage packs designed for heavy loads and a wide temperature range should reduce the capacity tolerance further. There is a strong correlation between cell balance and longevity.

Rechargeable lithium batteries produce 3.7 or 3.2 volts, depending on the type of battery and the chemicals it uses. To make batteries with higher voltages, manufacturers link identical batteries in a series circuit. In this way the voltages of the individual batteries are added together, so three 3.7-volt battery cells become one 12-volt battery (3.7x 3 = 11.1 volt). You can use the same electrical technique to create your own battery packs at home. Doing so requires basic math and no electronic skills.

Select the type of batteries from which to create a 12 volt rechargeable lithium battery pack. You might consider their size, shape or amp/hour capacity to be important, or you may just choose the batteries readily available where you live. It is important to use identical batteries in your pack. They must all have the same voltage and current characteristics.

Calculate how many batteries you need by dividing 12 by the voltage of the batteries.

Link together the batteries, connecting the positive terminal of the first battery to the negative terminal of the second. Link all the batteries in the same way, always joining opposite polarity terminals. You can stack cylindrical batteries, such as the A, C and D series batteries, on top of each other in a plastic or cardboard tube, or wrap them together in sticking tape. When using larger batteries with spring terminals, such as rectangular 6-volt batteries, join them with short lengths of wire.

Run a wire from the unused terminals at each end of the line of batteries. The voltage between the two wires is 12 volts.

If you want DIY for fan, Welcome to discuss and get help from Coremax Technical team. If you are looking for a professional 12 volt rechargeable lithium battery pack, please send business inquiry to Coremax. We are glad to offer all in one solution for you.

Lithium Battery Knowledge

Lithium batteries are already closely related to our lives, and our food, clothing, housing and travel are inextricably linked to them. However, many people do not understand lithium batteries. This is not limited to ordinary consumers. Even the designers of various electrical appliances have a smattering of knowledge about lithium batteries. The following will share a series of articles on lithium battery knowledge. Through these articles, everyone will have a systematic understanding of lithium batteries.

The lithium-ion battery mentioned here refers specifically to the secondary lithium-ion battery that can be recharged repeatedly, rather than the primary battery that is thrown away when it is used up. Lithium-ion batteries are distributed in every corner of our lives. Their application areas include mobile phones, tablet computers, notebook computers, smart watches, mobile power supplies (power banks), emergency power supplies, razors, electric bicycles, electric vehicles, electric buses, tourist vehicles, drones, and other power tools.As the carrier of electrical energy and the source of power for many equipment, it can be said that without lithium-ion batteries, today’s material world will not be able to play around (unless we want to go back decades).So, what is a lithium battery?

This article does not popularize the basic principles and development history of batteries. If you are interested, please check on Baidu. There are many stories here.The basic theories in the fields of physics and chemistry were basically confused by the wave of people before Einstein. Batteries are directly related to these two fields. The theories related to batteries were almost studied before World War II, and there was no major innovation after World War II.As a kind of battery technology, the theoretical research on lithium battery has not made any breakthroughs in recent years. Most of the research has focused on materials, formulas, processes, etc., that is, how to improve the degree of industrialization and develop lithium-ion batteries with better performance (store more energy and last longer).

How to Choose a Carrier of Energy

First of all, everyone will ask, why choose lithium as an energy carrier?  Well, although we don’t want to review the knowledge of chemistry, we have to go to the periodic table to find the answer to this question. Fortunately, everyone always remembers the periodic table, right?！I really don’t remember, let’s just take a minute to take a look at the table below.

If you want to be a good energy carrier, you must store and carry more energy in the smallest possible size and weight.Therefore, the following basic conditions need to be met：

1) The relative mass of atoms is smaller

2) Strong electronic ability to gain and lose

3) The proportion of electronic transfer should be high

Based on these three basic principles, the elements above the periodic table are better than the elements below, and the elements on the left are better than the elements on the right.For preliminary screening, we can only find materials in the first and second cycles of the periodic table: hydrogen, helium, lithium, beryllium, boron, carbon, nitrogen, oxygen, fluorine, and neon.Excluding inert gases and oxidants, only hydrogen, lithium, beryllium, boron, and carbon are left.

Hydrogen is the best energy carrier in nature, so the research of hydrogen fuel cells has always been in the ascendant, representing a very promising direction in the field of batteries.Of course, if nuclear fission technology can make major breakthroughs in the next few decades and can be miniaturized or even miniaturized, then portable nuclear fuel batteries will have broad room for development.

The next step is lithium. The choice of lithium as a battery is based on the relatively optimal solution we can find among all the current elements of the earth (the reserves of beryllium are too small, and it is a rare metal among rare metals).The dispute over the technical route of hydrogen fuel cells and lithium-ion batteries is in full swing in the field of electric vehicles, probably because these two elements are the better energy carriers we can find at present.Of course, there are also many commercial interests and even political games involved. These are not the areas to be discussed in this article.

By the way, the energy sources that already exist in nature and are widely used by mankind, such as oil, natural gas, coal, etc., are also mainly composed of carbon, hydrogen, oxygen and other elements (in the first and second cycles of the periodic table).Therefore, whether it is a natural choice or a human “design”, it will eventually go the same way.

How Lithium-ion Batteries Work

Let’s talk about the working mechanism of lithium battery. The redox reaction is not described here. Those with a bad chemical foundation, or those who have returned their chemical knowledge to the teacher, will feel dizzy when they see these professional things, so we should make a straightforward description.Borrow a picture here, this picture is easier for people to understand the principle of lithium battery.

According to the habit of use, we distinguish the positive electrode (+) and the negative electrode (-) according to the voltage difference during charge and discharge. The anode and cathode are not mentioned here, which is time-consuming and laborious.In this picture, the cathode material of the battery is lithium cobalt oxide (LiCoO2) and the anode material is graphite (C).

When charging, under the influence of an external electric field, the lithium element in the molecule of the cathode material LiCoO2 is detached and becomes a positively charged lithium ion (Li+). Under the action of the electric field force, it moves from the positive electrode to the negative electrode, and reacts chemically with the carbon atoms of the negative electrode to generate LiC6, so the lithium ions that run out of the positive electrode are very “stably” embedded in the graphite layered structure of the negative electrode.The more lithium ions that run out of the positive electrode and transfer to the negative electrode, the more energy this battery can store.

When discharging, it is just the opposite. The internal electric field turns, and the lithium ion (Li+) detaches from the negative electrode. Following the direction of the electric field, it runs back to the positive electrode and becomes a lithium cobalt oxide molecule (LiCoO2) again.The more lithium ions that run out of the negative electrode and transfer to the positive electrode, the more energy this battery can release.

During each charge and discharge cycle, lithium ions (Li+) act as the carrier of electrical energy, moving back and forth from the positive electrode to the negative electrode to the positive electrode over and over again, chemically reacting with the positive and negative electrode materials, converting chemical energy and electrical energy to each other, and realizing the transfer of charge. This is the basic principle of “lithium-ion battery”.Since electrolytes, isolation membranes, etc. are all insulators of electrons, there is no movement of electrons back and forth between the positive and negative electrodes during this cycle, they only participate in the chemical reaction of the electrodes.

The Basic Composition of Lithium Battery

To achieve the above functions, lithium battery need to contain several basic materials inside: positive electrode active substance, negative electrode active substance, isolation film, electrolyte.Let’s make a brief discussion below, what are these materials for?

It is not difficult to understand the positive and negative electrodes. To achieve charge movement, a positive and negative electrode material with a potential difference is required. So what is an active substance?We know that batteries actually convert electrical energy and chemical energy to each other to achieve energy storage and release.To realize this process, it is necessary that the positive and negative materials are “easy” to participate in chemical reactions, to be active, to be easy to oxidize and reduce, so as to achieve energy conversion, so we need “active substances” to be the positive and negative electrodes of the battery.

As already mentioned above, lithium is our preferred material for batteries, so why not use lithium metal as the active substance for electrodes?Isn’t this the maximum energy density that can be achieved?

Let’s look at the picture above again. The three elements oxygen (O), cobalt (Co), and lithium (Li) constitute a very stable cathode material structure (the proportion and arrangement in the figure are for reference only), and the carbon atom arrangement of the anode graphite also has a very stable layered structure.Positive and negative electrode materials must not only be lively, but also have a very stable structure in order to achieve orderly and controllable chemical reactions.What is the unstable result?Think about the burning of gasoline and the explosion of bombs, and the violent release of energy. The process of chemical reaction is actually impossible to accurately control artificially, so the chemical energy becomes heat energy, and the energy is released at once, and it is irreversible.

The lithium element in the metal form is too “lively”, and most naughty children are disobedient and like to destroy it.Early research on lithium batteries did focus on lithium metal or its alloy as the negative electrode, but because of outstanding safety issues, other better paths had to be found.In recent years, with people’s pursuit of energy density, this research direction has a trend of “resurrection with blood”, which we will talk about later.

In order to achieve chemical stability in the process of energy storage and release, that is, the safety and long life of the battery charge and discharge cycle, we need an electrode material that is lively when it needs to be lively and stable when it needs to be stable.After long-term research and exploration, people have found several metal oxides of lithium, such as lithium cobalt oxide, lithium titanate, lithium iron phosphate, lithium manganese oxide, nickel-cobalt-manganese ternary and other materials, as the active substance of the positive or negative electrode of the battery, to solve the above problems.As shown in the figure above, the peridot structure of lithium iron phosphate is also a very stable cathode material structure. The de-embedding of lithium ions during the charging and discharging process does not cause the lattice to collapse.Off topic, lithium metal batteries are indeed available, but compared with lithium-ion batteries, they are almost negligible. The development of technology will ultimately serve the market.

Of course, while solving the stability problem, it also brought serious “side effects”. That is, the proportion of lithium as an energy carrier was greatly reduced, and the energy density was reduced by more than an order of magnitude. Gains and losses, the natural way.

Graphite or other carbon materials are usually used as active substances for negative electrodes. They also follow the above principles. They require not only a good energy carrier, but also relatively stable, and relatively rich reserves, which are easy to manufacture on a large scale. Looking around, carbon is a relatively optimal solution.Of course, this is not the only solution. The research on anode materials is extensive, and it will be discussed later.

What do electrolytes do?In layman’s terms, it is the “water” in the swimming pool that allows lithium ions to swim around freely. Therefore, the ion conductivity should be high (the resistance to swimming is small), the electronic conductivity should be small (insulation), the chemical stability should be good (stability is overwhelming), the thermal stability should be good (all for safety), and the potential window should be wide.Based on these principles, after long-term engineering exploration, people have found electrolytes made of high-purity organic solvents, electrolyte lithium salts, and necessary additives. Electrolytes are formulated under certain conditions and in a certain proportion.Organic solvents include PC (propylene carbonate), EC (vinyl carbonate), DMC (dimethyl carbonate), DEC (diethyl carbonate), EMC (methyl ethyl carbonate) and other materials.Electrolyte lithium salts have LiPF6, LiBF4 and other materials.

The isolation film is added to prevent direct contact between the positive and negative electrode materials. We hope to make the battery as small as possible and store as much energy as possible, so the distance between the positive and negative electrodes is getting smaller and smaller, and short circuit has become a huge risk.In order to prevent the positive and negative electrode materials from shorting and causing a violent release of energy, it is necessary to use a material to “isolate” the positive and negative electrodes. This is the origin of the isolation film.The isolation film needs to have good ion permeability, mainly to open a channel for lithium ions to pass freely, and at the same time it is an insulator for electrons to achieve insulation between the positive and negative electrodes.At present, the main diaphragms on the market are single-layer PP, single-layer PE, double-layer PP/PE, three-layer PP/PE/PP composite film, etc.

The complete material composition of lithium battery

In addition to the four main materials mentioned above, in order to turn lithium-ion batteries from an “experimental product” in the laboratory into a product that can be used commercially, some other indispensable materials are also needed.

In addition to active substances, there are conductive agents and binders, as well as substrates and collectors used as current carriers (the positive electrode is usually aluminum foil).The binder should uniformly “fix” the lithium metal oxide as the active substance on the positive electrode substrate, and the conductive agent should enhance the conductivity of the active substance and the substrate to achieve a greater charge and discharge current. The collector is responsible for acting as a charge transfer bridge inside and outside the battery. The structure of the negative electrode is basically the same as that of the positive electrode. A binder is required to fix the active substance graphite, and copper foil is required as the substrate and the collector to act as the conductor of current.

However, because graphite itself has good electrical conductivity, the negative electrode generally does not add conductive agent material. In addition to the above materials, a complete lithium-ion battery also includes an insulating sheet, a cover plate, a pressure relief valve, a housing (aluminum, steel, composite film, etc.), and other auxiliary materials.

Production process of lithium battery

The production process of lithium-ion batteries is more complicated, and only some of the key processes are briefly described here.Depending on the assembly method of the pole piece, there are usually two process routes: winding and laminating.

The lamination process is to cut the positive and negative electrodes into small pieces and stack the isolation film to synthesize small cell monomers, and then stack the small cell monomers in parallel to form a large cell manufacturing process. The general process flow is as follows：

The winding process is to fix the positive and negative electrode sheet, isolation film, positive and negative electrode ear, protective tape, termination tape and other materials on the equipment, and the equipment is unwound to complete the battery cell production.

The common shapes of lithium-ion batteries are mainly cylindrical and square. Depending on the housing material, there are metal housings and soft-packed housings. Today, our  sharing is over. We will give more articles about lithium batterirs. Stay tuned

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