Lithium Ion Battery Circuit Is Simple

By On Oct 11, 2022

For now, we’ve gone through LiIon dealing with basics and mechanics. When it comes to designing your circuit around a LiIon battery, I believe you too could benefit from a cookbook with direct suggestions. Here, I would like to give you a collection of LiIon recipes that have worked well for me over the years.

I’m going to talk about single-series (1sXp) cell configurations, for a simple reason – multi-series configurations aren’t something I consider myself to have worked on much. The single-series configurations alone will result in quite a comprehensive work, but for those skilled in LiIon handling, I invite you to share your tips, tricks and observations in the comments section – last time we showed some interesting points. !

Contents

The Friendly Neighborhood Charger

There are many ways to charge the cells you just added to your device – a wide variety of chargers and other solutions are at your disposal. I would like to focus on one specific module that I believe is important for you to know more about.

You’ve probably seen the blue TP4056 boards around – they’re cheap and you’re one Aliexpress order away from owning a bunch, with a dozen boards costing just a few bucks. The TP4056 is a LiIon charger IC capable of charging your cells up to 1 A. Many TP4056 boards have a protection circuit built in, which means that such a board can also protect your LiIon cell from the outside world. This board itself can be treated as a module; for over half a decade now, the PCB footprint has remained the same, to the point where you can add a TP4056 board footprint to your own PCBs if you need LiIon charging and protection. I do this a lot – it’s much easier, and even cheaper, than soldering the TP4056 and all its supporting components. Here’s a KiCad token if you’d like to do that too.

This is a linear charger IC – if you want 1 A out, you need 1 A in, and the input-output voltage difference multiplied by current is converted into heat. Fortunately, the TP4056 modules are built to handle high temperatures quite well, and you can add a heatsink if you want. Maximum charging current is set by a resistor between ground and one of the pins, default resistor being 1.2 kΩ resulting in 1 A current; for low capacity cells, you can replace it with a 10 kΩ resistor to set a 130 mA limit, and you can find tables online for intermediate values.

There are some great things about the TP4056 IC that most people don’t know about if they use the modules as is. The IC’s CE pin is set to 5 V VIN, but if you lift that pin, you can use it to disable and enable charging via a logic level input from your MCU. You can check the charging current by connecting your MCU’s ADC to the PROG pin – the same pin used for the current setting resistor. There is also a thermistor pin, usually wired to ground, but adaptable for a wide range of thermistors using a resistive divider, whether it’s the thermistor connected to your bag cell or one you’ve added externally to your 18650 holder.

There are also issues with the TP4056 – it’s a pretty simple IC. Efficiency is not an absolute necessity where wall power is available, but the TP4056 wastes a decent amount of power as heat. A switching charger-based module avoids this, and often also allows you to charge at higher currents if ever needed. Connecting a cell in reverse kills the chip, and also the protection circuit – this mistake is easy to make, I’ve done it a lot, and this is why you need spares. If you reverse the cell contacts, discard the board – don’t load your cells with a faulty IC.

Also, given the popularity of the TP4056, copies of this IC are manufactured by multiple different chip vendors in China, and I have observed that some of these copy ICs break more easily than others, for example, no longer charging your cells – again, save. spare The TP4056 also doesn’t provide charge timers like other more modern ICs – a topic we touched on in the comments section of the first article.

All in all, these modules are powerful and quite versatile. It’s even safe to use them to charge 4.3 V cells, because due to the CC/CV operation, the cell simply won’t charge to its full capacity – extending your cell’s life as a side effect. When you need to bypass such modules, there are tons of ICs you can use – smaller linear chargers, switching chargers, chargers with built-in power path and/or DC-DC regulation functions, and a bunch of ICs that do LiIon. charging as a side effect. The world of LiIon charger ICs is huge and there is much more to it than the TP4056, but the TP4056 is a fantastic starting point.

The Protection Circuit You Will See Everywhere

As with charging ICs, there are many designs out there, and there is one you should know about – the DW01 and 8205A combination. It’s so ubiquitous that at least one of your store-bought devices probably contains it, and the TP4056 modules also come with this combo. The DW01 is an IC that monitors the voltage of your cell and the current going to and from it, and the 8205A is two N-FETs in a single package, helping with the actual “connect-disconnect the battery” part. There is no additional current sense resistor – instead, the DW01 monitors voltage across the 8205A junction. In other words, the same FETs used to cut the cell from the outside world in case of failure, are used as current sensing resistors. This design is cheap, generic and works wonders.

The DW01 protects against overcurrent, overcharge and overdischarge – the first two occur relatively often in hobbies, and the latter is handy if your charger ever goes bad. If something wrong happens, it interrupts the connection between the negative terminal of the cell and GND of your circuit, in other words, it does low-side switching – for a simple reason, FETs that interrupt GND are cheaper and have lower resistance. We’ve also seen some hacks done with this chip – for example, we covered research by a hacker who found that the DW01 can be used as a soft power switch for your circuit – in a way that doesn’t compromise. safety You just need to connect a GPIO pin of your MCU to the DW01, preferably with a diode – this comment describes an approach that seems quite unsuccessful to me.

When you first connect a LiIon cell to the DW01 + 8205A combination, sometimes it will enable its output, but sometimes it won’t. For example, if you have a holder for 18650s and a protection circuit connected to it, there is a 50/50 chance that your circuit will trip after you insert the battery. The solution is simple – either connect a charger externally, or short-circuit the OUT- and B- with something metal (I often add an external button), but it is troublesome to deal with. Just like TP4056, the DW01 + 8205A combo dies if you connect the battery in reverse. Also, the DW01 is internally wired for a 2.5 V over-discharge cut-off, which technically cannot be changed. If you don’t have a separate program-controlled cut-off, the FS312 is a pin-compatible DW01 replacement with a 3.0 V overdischarge point, helping you extend the life of your cell.

You can buy a set of ready-made protection circuit modules, or simply use the protection circuit arranged on the TP4056 module PCB. You can also build up a decent stock of protective circuits by taking them out of single cell batteries whenever the cell swells or dies – be careful not to puncture the cell while doing it, please.

All The Ways To Get 3.3 V

For a 4.2 V LiIon cell, the useful voltage range is 4.1 V to 3.0 V – a cell at 4.2 V quickly drops to 4.1 V when you draw power from it, and at 3.0 V or lower, the internal resistance of the cell usually rises quite a bit quickly that you will no longer get much useful current from your cell. If you want to get to 1.8V or 2.5V, that’s no problem, and if you want to get to 5V, you’ll use some boost. However, most of our chips still run at 3.3 V – let’s see what our options are here.

When it comes to LiIon range to 3.3 V regulation, linear regulators closely follow switching regulators in terms of efficiency, often have lower quiescent (no-load) current if you’re looking for low-power operation, and lower noise if you want to do analog stuff. . That said, your regular 1117 won’t work – it’s an old and inefficient design, and the 1117-33 starts grinding its gears at about 4.1 V. Instead, use pin-compatible, low-removal-voltage replacements like the AP2111, AP2114 and BL9110, or AP2112, MIC5219, MCP1700 and ME6211 if you are ok with SOT23 stuff. All of these are linear regulators comfortable supplying 3.3 V with input up to 3.5 V and sometimes even 3.4 V if you’d like to drive something like an ESP32. It’s hard to deny the simplicity of using a linear regulator – one chip and a few caps are all it takes.

If you want 500 mA to 1000 mA or even more current on a continuous basis, a switching regulator will be your best friend. My personal favorite is the PAM2306 – this regulator is used on the Raspberry Pi Zero, it’s very cheap and accessible, and even has two separate output rails. Given its ability to perform 100% duty cycle operation, it can squeeze a lot of juice out of your cells, often desirable for higher power projects where runtime is important. And hey, if you got a Pi Zero with a dead CPU, you won’t go wrong by cutting off part of the PCB and soldering some wires to it. When designing your own board, use datasheet recommendations for inductor parameters if the whole “choosing the right inductor” business has you confused.

So, the PAM2306 is the regulator on the Pi Zero, and it’s also LiIon friendly? Yes, you can power a Pi Zero directly from a LiIon battery, as all the onboard circuitry works up to 3.3 V on the “5 V” pins. I have extensively tested it on my own devices, and it even works with the Pi Zero 2 W. Combined with this power path and charger, you have a complete “battery-powered Linux” package, with all the power that Raspberry Pi. provides – at the cost of only a handful of components. One problem to watch out for is that MicroUSB port VBUS will have battery voltage – in other words, you’d better fill the MicroUSB ports with hot glue in case someone plugs a MicroUSB PSU in there, and tap the USB data test points for USB. connectivity

A Power Path To Join Them All

Now, you have a load, and you have your 3.3 V. There is one problem I should remind you about – while you are charging the battery, you cannot draw current from it, because the charger relies on current measurements. check load; if you mistake the charger for an extra charge, you risk overcharging the battery. Fortunately, since you have a charger plugged in, you should have 5V accessible. It would be nice if you could power your devices from that 5 V source when it’s present, and use the battery when it’s not! We usually use diodes for such power decisions, but this would cause additional voltage drop and power losses during battery operation. Fortunately, there is a simple three-component circuit that works much better.

In this power path circuit, a P-FET takes the role of one of the diodes, with a resistor opening the FET while the charger is not present. The P-FET has no voltage drop, but instead has a resistance in fractions of an ohm, so you avoid losses when the charger is not plugged in. Once the charger is connected, the FET closes, and the charger powers your circuit through. the diode instead. You need a logic level P-FET – an IRLML6401, CJ2305, DMG2301LK or HX2301A would do, and there are a thousand others that will work. As for diode, a default Schottky like 1N5819 (SS14 for SMD) will do. It is a ubiquitous circuit and deserves its place in circuit toolboxes.

You can buy shields and modules that contain all these parts and sometimes more, on a single board. You can also buy ICs that contain all or some parts of this circuit, often improved, and not worry about the specifics. These ICs tend to be more expensive, however, and much more subject to chip shortages than the individual component-based solution. In addition, when problems arise, an understanding of internal functions helps a lot. That way, it’s important that the basics are demystified for you, and you don’t feel compelled to reuse power bank boards the next time you want to make your device portable.

Pay attention to what other boards are doing. Often, you’ll see the charger + regulator + power path circuit described above, especially on cheaper boards with chips like the ESP32. Other times, you’ll see more involved power management solutions, such as power bank chips or PMICs. Sometimes they will work much better than the simple circuit, sometimes it’s the opposite. For example, some TTGO battery-powered boards use power bank chips and overcomplicate the circuit, resulting in strange behavior and malfunctions. A different TTGO board, on the other hand, uses a PMIC that is much more suitable for such boards, resulting in flawless operation and even granular power management for the user.

Hack Portable Devices Like You Couldn’t Before

Now you know what it takes to add a LiIon input connector to your project, and the secrets behind the boards that already come with one. It’s a feeling like no other, taking a microcontroller project with you while you test your concept. I hope I brought you closer to experiencing it.

Next time, I’d like to talk about batteries with multiple cells in series – BMSs, balancing and charging LiIon packs from different sources. That will take a good amount of time for me to prepare though, as I’d like to finish some related projects first, and I recommend you check out this coverage of ours if you’d like to learn about it. In the meantime, I wish you the best of luck in building your kitchen projects!

What is the difference between lithium-ion and lithium battery?

The main difference between lithium batteries and lithium ion batteries is that lithium batteries are primary cells and lithium ion batteries are secondary cells. The term "primary cell" refers to cells that are not rechargeable. on the other hand, lithium ion batteries have a secondary cell construction.

Which battery is better Li-ion or lithium? Both lithium-ion and lithium-poly batteries are suitable with high and durable power applications. However, lithium-ion batteries are more efficient and popular than lithium-polymer. They have higher energy levels and powers and are more suitable for heavy usage.

Is a Li ion battery a lithium battery?

A lithium-ion (Li-ion) battery is an advanced battery technology that uses lithium ions as a key component of its electrochemistry. During a discharge cycle, lithium atoms in the anode are ionized and stripped of their electrons.

Can I take a lithium-ion battery on a plane?

Spare (uninstalled) lithium metal batteries and lithium ion batteries, electronic cigarettes and vaping devices are prohibited in checked baggage. They must be carried with the passenger in carry-on luggage.

Is Lithium Battery same as Li ion?

The difference between lithium and lithium-ion batteries is that one is non-rechargeable (primary cell) and the other is rechargeable (secondary cell). In addition to this, lithium batteries have a shelf life of up to four times longer than lithium-ion batteries and are also much cheaper and easier to manufacture.

What are the two types of lithium batteries?

There are three types of cells that are used in lithium batteries: cylindrical, prismatic, and pouch cells.

Are lithium batteries a limited quantity item?

It is true that lithium batteries shipped under DOT’s Hazardous Materials Regulations cannot be shipped under the limited quantity exceptions. However, if properly classified and packaged, lithium batteries can receive as much or more relief from the regulations than limited quantity shipments.

Are lithium-ion batteries limited? The lithium ions move directly through the electrolyte and do not react with other elements. As far as lithium batteries have come, today’s technology is still limited.

Is lithium in limited supply?

The IEA says the world could face a lithium shortage by 2025. And Credit Suisse says lithium demand could triple between 2020 and 2025, meaning “supply would be tight.” Campaign group Transport and Environment says there is only enough lithium to produce up to 14 million EVs in 2023, Reuters reports.

Why is there a shortage of lithium?

MELBOURNE, Jan 21 (Reuters) – Lithium is in high demand due to rapidly growing production of electric vehicles that use lithium-ion batteries, but there is a global supply shortage of the metal, and Western countries are racing to bring in new mines to compete. with China.

Is lithium a limited quantity item?

Size limits: Lithium metal (non-rechargeable) batteries are limited to 2 grams of lithium per battery. Lithium ion (rechargeable) batteries are limited to a 100 watt hour (Wh) rating per battery. These limits allow for almost all types of lithium batteries used by the average person in their electronic devices.

Is there a large supply of lithium?

With 8 million tons, Chile has the world’s largest known lithium reserves. This puts the South American country ahead of Australia (2.7 million tons), Argentina (2 million tons) and China (1 million tons). Within Europe, Portugal has smaller amounts of the valuable raw material.

What are the limits of lithium batteries?

Limitations on lithium content for air travel Lithium packs are rechargeable and power laptops, mobile phones and video cameras. Both battery types, including spare packs, are allowed as carry-on, but cannot exceed the following lithium content: 2 grams for lithium metal or lithium alloy batteries.

What limitations do lithium batteries have?

Despite its general advantages, lithium-ion has its disadvantages. It is delicate and requires a protective circuit to maintain safe operation. Built into each pack, the protection circuit limits the peak voltage of each cell during charge and prevents the cell voltage from dropping too low during discharge.

Can I take lithium ion batteries on a plane 2022?

Spare (uninstalled) lithium ion and lithium metal batteries, including power banks and mobile phone battery charging boxes, must be carried in carry-on luggage only.

What is the largest problem with lithium ion batteries?

It takes 6 kilograms to store the same amount of energy in a lead-acid battery that a 1-kilogram lithium-ion battery can handle. However, lithium-ion batteries are extremely sensitive to high temperatures and inherently flammable. These batteries tend to degrade much faster than they normally would, due to heat.

Are lithium batteries in short supply?

Given the demand from electric car manufacturers, suppliers and governments are bound to mine more of it.

Are we running out of lithium?

Because lithium is not an infinite resource. In fact, according to Kipping, once EVs dominate the car market, there is about 70 years worth of lithium until the identified global reserves are themselves exhausted. After that, we would have to turn to pulling lithium from the sea, which is a much more expensive proposition.

Why is there a shortage of lithium?

Is there enough lithium to support electric cars?

The short answer is yes, we do have enough lithium for electric cars. If you even loosely follow the EV (electric vehicle) market, you will know that there is a lot of talk about the demand for lithium used for electric car batteries.

What does battery protection mean?

Function of the battery protection mode: The battery protection mode protects the battery. If the state of charge (SOC) of the battery falls below the thresholds, battery protection mode is activated.

Why is my car in battery protection mode? When load reduction is activated, the message âBattery Saver Onâ or âBattery Saver Modeâ will appear in the instrument display. These messages indicate that the vehicle battery has a low state of charge and continues to lose electrical charge at a rate that the charging system cannot sustain.

What does battery protection mode mean?

The battery protection mode protects the battery. If the state of charge (SOC) of the battery falls below the thresholds, battery protection mode is activated.

Should you use battery protection mode?

Especially in your case because you want to keep it connected 24/7, the battery protection mode is a perfect match, I strongly recommend enabling battery protection mode. Because without this battery protection mode the phone would always charge the battery from around 90% to 100%.

How do I disable battery protection?

How do I turn off battery protection?

What is battery protection mode on a tablet?

The “Protect battery” feature limits the devices’ charge level to 85 percent, preventing the full charge to 100 percent, which is thought to wear down batteries over years of use.

How do I turn off battery saver on Samsung?

Most Android devices have a built-in battery optimizer that manages the device’s apps to conserve battery….Battery Saver Settings:

Go to your phone settings.
Tap Battery.
Make sure Battery Saver and Super Battery Saver are turned off.

What does a battery protection board do?

Battery protection circuits help ensure that lithium-ion cells connected in series are protected against overcharging, over-discharging, excessive current draw and short circuits. If li-ion batteries are mishandled, then they will get damaged.

What is a BMS Protection Board?

The BMS protection board for li-ion is responsible for monitoring and protecting the battery cells, and it has some settings that you need to be aware of. In this article, we will discuss the most important BMS protection settings and what they mean for your battery.

Do I need a battery protector?

Battery protection is extremely important because it helps motorists avoid the hassle and expense of a flat battery.

Why do lithium-ion batteries fail?

LiBs are sensitive to high power charging (quick charging), too high or too low operating temperature, and mechanical abuse which eventually leads to capacity fading, short circuit, and the danger of thermal runaway [3,5,6,7, 8,9]. Repeated rapid charging can accelerate battery aging, resulting in shorter battery life.

What is the biggest problem with lithium-ion batteries? It takes 6 kilograms to store the same amount of energy in a lead-acid battery that a 1-kilogram lithium-ion battery can handle. However, lithium-ion batteries are extremely sensitive to high temperatures and inherently flammable. These batteries tend to degrade much faster than they normally would, due to heat.

How often do lithium-ion batteries fail?

Lithium-ion batteries have a failure rate that is less than one in a million. The failure rate of a quality Li-ion cell is better than 1 in 10 million. Industrial batteries, such as those used for power tools, are generally stronger than those in consumer products.

Can a lithium battery last 20 years?

Lithium-ion batteries last 15–20 years, 3 times longer than the 5–7 years for lead-acid batteries.

What is a major problem with lithium batteries?

Lithium-ion batteries contain metals such as cobalt, nickel and manganese, which are toxic and can contaminate water supplies and ecosystems if they leach from landfills. Additionally, fires in landfills or battery recycling facilities have been attributed to inappropriate disposal of lithium-ion batteries.

What is the life expectancy of a lithium-ion battery?

The typical estimated life of a lithium-ion battery is approximately two to three years or 300 to 500 charge cycles, whichever comes first. One charge cycle is a period of use from fully charged, to fully discharged, and fully recharged again.

Why do lithium batteries not last forever?

What Causes Lithium Ion to Age? The lithium ion battery works on ion movement between the positive and negative electrodes. In theory such a mechanism should work forever, but cycling, elevated temperature and aging reduce performance over time.

How many years can a lithium battery last?

The bottom line So, how long do Lithium-ion batteries last? To sum it all up, the bare minimum most manufacturers expect from their batteries is about 3 years or 1,000 charge cycles (whichever is less).

Will we run out of lithium for batteries?

Can a lithium battery last 20 years?

Lithium-ion batteries last 15–20 years, 3 times longer than the 5–7 years for lead-acid batteries.

What destroys a lithium-ion battery?

Heat. There have been several cases of lithium-based batteries catching fire in extreme heat conditions. Batteries under heat stress combined with some additional, unexpected pressure or short circuit can ‘explode’, leaving a destroyed battery and, more often than not, a damaged piece of wearable technology.

What can damage lithium-ion batteries?

Damage to lithium-ion batteries can occur when the batteries themselves or the environment around the batteries is below freezing (32°F) during charging. Charging in temperatures below freezing can lead to permanent lithium metal build-up (ie, coating) on the anode, increasing the risk for failure.

What kills a lithium battery?

Elevated temperature and high currents also affect cycle life. * 100% DoD is a full cycle; 10% is very short. Cycling in an intermediate state of charge would have the best longevity. Lithium-ion suffers from stress when exposed to heat, thus keeping a cell at a high charging voltage.