Lithium batteries, or Lithium-ion Polymer (LiPo) batteries, are batteries that use Lithium as a negative electrode material and use a non-aqueous electrolyte solution. In 1912, Lithium metal batteries were first proposed and studied by Gilbert N. Lewis. In the 1970s, M.S. Whittingham proposed and started researching Lithium-ion batteries. However, due to the complications of using the unstable Lithium metal, the batteries were not popular at the time.

It is now with further development that Lithium-ion Polymer batteries have fast become a preferred power source for many applications and industries.  It is for this reason that we will explore the charging cycles of lithium-ion polymer batteries in-depth in this article.

 

What is a charging cycle?

Some consumers may have that the charge and discharge life of lithium-ion polymer batteries is “500 times.” But what is “500 times?” It refers to the number of charge and discharge cycles of the battery.

 

Let us look at an example: Let us say there is a lithium battery that uses only half of its charge in one day and is then charged fully.  On the next day, it again only uses half of its power.  Although the battery has been charged twice, this does not count as one charge cycle but two.

 

A charging cycle is when a battery goes from being fully charged to empty and then from empty to fully charged; this is not one single charge. Just based on the previous example, it’s clear that it can usually take several charges to complete a cycle.

 

Every time a charging cycle is completed, the battery capacity decreases a bit. However, the reduced capacity is very small. High-quality batteries will still retain 80% of their original capacity after many cycles of charging. Many lithium battery products will still be used after two or three years. Of course, after the end of the lithium battery life, it still needs to be replaced.

 

Ultimately, a 500-cycle life means that a manufacturer has achieved about 625 recharge times at a constant discharge depth (such as 80%) and reached 500 charging cycles.  In other words, if we ignore other factors that could reduce the Lithium-ion battery capacity and we take 80% of 625, we receive 500.

 

However, due to various factors in life, especially considering how the depth of discharge (DOD) during charging is not constant, “500 charging cycles” can only be used as a reference to battery life.

 

Overall, it is better to think of the life of the lithium battery as related to the number of times the charging cycle is completed and not as directly related to the number of charges.

Deep and shallow charging

Here is another way to think of the cycle lives of lithium-ion polymer batteries: the life of a Lithium battery is generally 300 to 500 charging cycles. Assume that the capacity provided by a full discharge is Q. If the capacity reduction after each charging cycle is not considered, lithium batteries can provide or supplement 300Q-500Q power in total during its life. From this we know that if you use 1/2 each time, you can charge 600-1000 times; if you use 1/3 each time, you can charge 900-1500 times. By analogy, if you charge randomly, the number of times is uncertain. In short, no matter how a Lithium battery is charged, it is constant to add a total of 300Q to 500Q of power. Therefore, we can also understand this: the life of a Lithium battery is related to the total charge of the battery and has nothing to do with the number of charges. The effects of deep charging and shallow charging on lithium battery life are similar.

 

In fact, shallow discharge and shallow charges are more beneficial to lithium batteries. It is only necessary to deep charge when the power module of the product is calibrated for lithium batteries. Therefore, lithium-ion-powered products do not have to be constrained by the process: they can be charged at any time without worrying about affecting the battery life.

 

Effects of temperature on battery life

If a Lithium-ion Polymer battery is used in an environment higher than the specified operating temperature (above 35℃), the battery’s power will continue to decrease.  In other words, the battery’s power supply time will not be as long as usual. If a device is charged at such temperatures, the damage to the battery will be greater. Even if the battery is stored in a hot temperature environment, it will inevitably cause damage to the battery. Therefore, it is a good idea to extend the life of lithium-ion polymer batteries by using it under normal operating temperatures as often as possible.

If you use Lithium batteries in a low-temperature environment (below 4℃), the battery life will also be reduced. Some older Lithium batteries of mobile phones cannot even be charged under low temperatures.  However, unlike in high temperatures, once the temperatures rise, the molecules in a battery will heat up and immediately return to the previous charge.

Having explored battery performance under these extreme temperatures, the question now becomes if there are any batteries that can be used in environments with low or high temperatures.

Currently, GREPOW’s batteries can be used at temperature ranges of -50 ℃ to 50 ℃ or 20 ℃ to 80 ℃. Our low-temperature Lithium batteries’ discharging current of 0.2C at -50℃ is over 60% efficiency, over 80% efficiency at -40℃, and around 80% efficiency at -30℃.

We can further custom-make batteries depending on your specifications.

Charge-discharge cycle

To get the most out of lithium-ion batteries, you need to use it often so that the electrons in the Lithium batteries are always in a flowing state. If you do not use lithium batteries often, please remember to complete a charging cycle every month and do a power calibration, i.e. deep discharge and deep charge, once.

 

After the nominal number of charge and discharge cycles is used up, a battery’s ability to store power will drop to a certain level, but the battery can continue to be used.

 

Lithium batteries have no limit on the number of times they can be recharged. Regular manufacturers can charge and discharge batteries at least 500 times, and the capacity is maintained at more than 80% of the initial capacity. If charged and discharged once a day, batteries can be used for two years. Usually, batteries in mobile phones are charged 1000 times or more, which causes the batteries to be severely non-durable.

 

Below is a proper method of maintaining your mobile device’s battery:

 

When you charge your phone, fully charge it each time.

• Do not fully discharge the battery. The battery needs to be charged when the power is less than 10%.
• Charge with the original charger; do not use a third-party charger.
• Do not use your mobile phone while it is being charged.
• Don’t overcharge: stop charging after the battery is full.

According to the experimental results, the life of a lithium battery continuously declines with an increase in the number of charges.

Lithium battery cycle specified by the national standard

In order to measure how long the rechargeable battery can be used, the definition of the number of cycles is specified. Actual users use a wide variety of tests because tests with different conditions are not comparable, and the comparison must define the definition of cycle life.

 

Lithium battery cycle life test conditions and requirements specified by the national standard are as follows:Charge at 1C under the environment temperature of 20 ° C ± 5 ° C. When the battery terminal voltage reaches the charging limit voltage of 4.2V, change to constant voltage charging until the charging current is less than or equal to 1 / 20C, stop charging, leave it for 0.5h to 1h, and then discharge it at 1C to the termination voltage of 2.75V.

 

After the discharge is completed, leave it for 0.5h to 1h, and then perform the next charge and discharge cycle two consecutive times. Less than 36min, the end of life is considered, and the number of cycles must be greater than 300 times.

Having gone over the national standard, we should explain the following:

1. The standard specifies that the cycle life test is performed in a deep charge and deep release mode.

 

2. The cycle life of the lithium battery is specified. According to this model, the capacity is still more than 60% after ≥300 cycles.

 

However, the number of cycles obtained by different cycling systems is quite different. For example, the other conditions above are unchanged, and only the constant voltage of 4.2V is changed to a constant voltage of 4.1V for the cycle life of the same type of battery. In this way, the battery is no longer under a deep charge, and the cycle of life can be increased by nearly 60%. Then if the cut-off voltage is increased to 3.9V for testing, the number of cycles should be increased several times.

 

With regard to this statement that the charge and discharge cycle is one less life, we should pay attention to the definition of the charging cycle of a lithium battery: a charging cycle refers to the full charge of the lithium battery from empty to full, and then from empty to full the process of. And this is not the same as charging once.

 

In addition, when we talk about the number of cycles, we cannot ignore the conditions of the cycle. It is meaningless to talk about the number of cycles aside from the rules because the number of cycles is just a way to measure battery life.

 

If you want to learn more about batteries or our custom-made batteries, please contact us at sales@himaxelectronics.com and visit our website: https://himaxelectronics.com/

Lithium polymer battery is a kind of lithium-ion battery, but it has obvious advantages over liquid lithium battery (with high energy density, more compact, ultra-thin, lightweight, and high safety and size), is a novel battery. Below we detail the advantages of lithium polymer batteries.

1. Good safety performance

Lithium polymer batteries are structured in soft aluminum-plastic packaging, which is different from the metal case of liquid batteries. Once a safety hazard occurs, the liquid batteries are liable to explode, and the lithium polymer batteries can only be inflated.

2. Can be made thinner

Ordinary liquid lithium batteries adopt the method of customizing the casing first and then plugging the positive and negative electrodes. The thickness is less than 3.6mm. There is a technical limitation. The lithium-polymer battery does not have this problem. The thickness can be less than 1mm( ultra-thin battery can be 0.4mm in thickness), which meets the current mobile phone requirements.

3. Lightweight

Batteries with polymer weights do not require a metal case as protective packaging. Lithium polymer batteries are 40% lighter than steel-case lithium batteries of the same capacity and 20% lighter than aluminum-case batteries.

4. Large capacity

Polymer batteries have a capacity 10 ~ 15% higher than steel-case batteries of the same size and specifications, and 5 ~ 10% higher than aluminum-case batteries. They have become the first choice for color screen mobile phones and MMS mobile phones. The newest color screen and MMS mobile phones currently on the market also Polymer batteries.

5. Small internal resistance

The internal resistance of lithium polymer batteries is smaller than that of ordinary liquid batteries. At present, the internal resistance of domestic polymer batteries can even be less than 35mΩ, which greatly reduces the self-power consumption of the battery and extends the standby time of the mobile phone. It is completely possible. Reached the level of international standards. This kind of polymer lithium battery that supports large discharge current is an ideal choice for remote control model, and it has become the most promising product to replace the nickel-metal hydride battery.

6. The shape can be customized

Lithium polymer batteries can increase or decrease the cell thickness according to customer needs, develop new cell models, are cheap, have short mold opening cycles, and some can even be tailored to the shape of the cell phone to fully utilize the battery case space and enhance the battery capacity.

7.Good discharge characteristics

Lithium polymer batteries use colloidal electrolytes, which are subdivided into liquid electrolytes. Colloidal electrolytes have stable discharge characteristics and a higher discharge platform.

8.Simple protection plate design

Because of the use of polymer materials, the battery core does not ignite, does not explode, and the battery core itself has sufficient safety. Therefore, the protection circuit design of lithium polymer batteries can consider omitting PTC and fuses, thereby saving battery costs.

HIMAX specializes in custom, semi-custom, and off-the-shelf lithium polymer batteries. With over 15 years of customer service experience, HIMAX has developed a very complete service system, specifically tailored for our customers, which helps us in better understanding your needs in the first step of our communication, in a highly time-efficient way.

 

If you are interested in our lithium polymer batteries, please don’t hesitate to contact us at any time!

Email: sales@himaxelectronics.com

Himax Website: https://himaxelectronics.com/

A standardized battery fits into any compatible compartment – after all, that’s why standards are defined. Depending on the application, however, button cells and cylindrical batteries reach their limits.

A Smartwatch, for example, has a significantly higher energy consumption than an ordinary wristwatch. A simple button cell is therefore far from sufficient to cover the device’s power requirements. However, the case of the watch is far too small for a powerful lithium-ion battery. Only a lithium polymer battery is capable of meeting the specific requirements of a Smartwatch.

 

Flexible product design

Lithium polymer technology is a match to lithium ion batteries in terms of performance, but is much more flexible in terms of design and size. The reason for this is the absence of a solid metal housing, as is common with lithium-ion batteries. Instead, the cells are merely enclosed by a thin layer of plastic-laminated aluminum foil. Thanks to the sandwich-like structure of the battery cells, even curved or ultra-flat designs with a thickness of less than one millimeter are conceivable.

 

For product developers and designers, the great flexibility of Lithium-Polymer batteries is a blessing. Conversely, the new design freedom can also lead to uncertainty. It is therefore advisable to take battery developers such as Jauch Quartz GmbH on board at an early stage for new developments.

 

The following six parameters must be defined at an early stage if design-in is to be successful.

 

1) Voltage

The average single cell voltage for lithium polymer cells is 3.6 volts as standard. The switch-off voltage is 3.0 volts and the maximum charging voltage is 4.2 volts. If a higher voltage is required, several cells can be connected in series. A parallel connection of several cells also makes it possible to increase the capacity.

 

2) Currents

In addition to the voltage, the current requirement of the application must also be defined. The average continuous currents must be specified as well as the maximum pulse currents and pulse lengths. The inrush currents and their lengths must also be taken into account.

 

3) Temperature

In connection with the current power load profiles of the application, the temperatures at which they are used must also be taken into consideration. By default, lithium polymer cells are designed for a temperature range between -20 and 60 degrees Celsius. Temperatures between 0 and 45 degrees Celsius should prevail when charging the cells.

 

Special cells are available for use under extreme temperature conditions above or below this range.

 

4) Dimensions of the Battery Compartment

Of course, the dimensions of the battery compartment must also be defined in advance. It is important to remember that lithium polymer cells expand over time. This “swelling” phenomenon is responsible for the cells to become up to 10% thicker over time. Accordingly, the battery compartment should be generously dimensioned. In addition, sharp edges or the like in the immediate vicinity of the battery compartment must be avoided at all costs so that the battery is not damaged.

 

5) Capacity

The capacity of a battery indicates the amount of electrical charge that a battery can store or release. Capacity is determined by voltage, current consumption, temperature and the available space in the battery compartment.

 

6) Safety

To protect lithium polymer batteries from overcharging, deep discharge or short circuits, they are equipped with individually programmable protection electronics. In order to optimally adapt this so-called “battery management system” to the respective application, individual switch-off values for the system are defined.

 

In addition, batteries must meet certain norms and safety standards to ensure that the applications are approved. Strict regulations apply here – understandably – especially in the field of medical technology.

 

Based on these six parameters, Jauch’s battery experts will find the right lithium polymer battery solution for every application. In order to guarantee optimum results, however, contact should be made as early as possible in the design-in phase. Otherwise, the desired battery solution may not be available or feasible.

How lipo battery’s performance affected by temperature?

I think everyone here must have the similar experience with me, your smartphone will consume very fast, your phone will dead for only half a day. In fact, the lithium-ion polymer batteries are the vast majority used of smartphones, and a variety of factors will affect the performance of the lipo battery. These factors are similar to RC devices such as our drones and RC car. Especially for temperature factors, so let’s talk about how temperature affects the performance of the battery and why it affects it.

Does temperature affect lipo battery’s performance?

Battery in high temperature or low-temperature environment affect the performance of the battery? Let’s first look at the following chart:

I think everyone here must have the similar experience with me, your smartphone will consume very fast, your phone will dead for only half a day. In fact, the lithium-ion polymer batteries are the vast majority used of smartphones, and a variety of factors will affect the performance of the lipo battery. These factors are similar to RC devices such as our drones and RC car. Especially for temperature factors, so let’s talk about how temperature affects the performance of the battery and why it affects it.

Does temperature affect lipo battery’s performance?

Battery in high temperature or low-temperature environment affect the performance of the battery? Let’s first look at the following chart:

We can see that during the battery used, the higher electric current, faster voltage decay speed, and overload of the high current is more likely causing the battery to be over-discharged and damaged (safety level reduced, life decay is too fast). Therefore, the ambient temperature has a great influence on the performance of the battery, and the lower the temperature, the lower the discharge platform and efficiency.

Low temperature harm battery capacity

The optimal level of operating temperature for lithium batteries is 0 to 35℃. The low-temperature environment will reduce the activity of lithium ions, the lipo battery discharge capacity will be weak, and the use time will be shortened. If the lithium battery using in a low-temperature environment for a short period of time, the damage is only temporary and does not damage the battery capacity. The performance will recover when reinforcing the temperature.

However, if the battery is charged and discharged in a low-temperature environment for a long time, metal lithium will be separated out on the surface of the “battery anode”. This process is irreversible and permanently damage to the battery capacity. Like sometimes, at low temperatures, our smartphone will automatically shut down. It is for the purpose of protecting the battery, on the other side, it is also caused by the unqualified and aging of the self-battery.

So, how to use batteries in an extreme environment?

Recommendations in Summer, or High temperature environment:

– Charging

The charging temperature range from 5 to 45°C;

The upper limit voltage of charging shall not exceed 4.22V. The temperature at the period of charging shall not exceed 45 °C;

Charging needs to be charged at room temperature (≤35 °C), used within 48 hours after charging, if not used, timely discharge to the storage voltage (3.8-3.9V);

The battery cannot be charged immediately after high-temperature discharge or high temperature, and the battery surface temperature can be charged below 40 °C.

Must use the manufacturer’s matching charger for charging, can not illegally use other equipment to carry out large current on the battery (≥1.5C)

The upper limit voltage of charging shall not exceed 4.22V. The temperature during charging shall not exceed 45 °C.

– Discharge

The temperature range during discharge is within 45 ° C;

The discharge current shall not exceed the maximum current identified in the specification;

The lower limit alarm voltage of discharge shall not be lower than 3.6V, the rebound voltage shall not be lower than 3.65V, and the surface temperature of the battery after high current discharge shall not exceed 70°C;

The battery should not be exposed to the sun before and after discharge. The surface temperature of the battery before discharge should not exceed 45 °C.

Recommendations in Winter, or Low temperature environment:

– Charging

Charging should be carried out at room temperature (5 ° C or above, 20 ° C is best), such as indoors, cars, etc., and can not be charged in high ≥ 40 °C environment;

Retrieving the battery from the outside cannot be charged immediately, and then charging the battery after the surface temperature of the battery reaches the room temperature environment;

must use the manufacturer’s matching charger for charging, can not illegally use other equipment to carry out large current on the battery (≥1.5C)

– Discharge

After discharge, the battery should be effectively insulated (such as using a thermos cup, incubator, etc.) to ensure that the temperature of the battery body is kept above 10 °C, 20 °C is best.

After the battery is loaded into the aircraft, it is necessary to check the remaining battery power from the APP, and whether the voltage information is abnormal;

When the battery temperature does not reach 20 °C or above, it is not suitable for large maneuvering.

Compared with the room temperature (about 20 °C), the battery life of the battery will be significantly shortened in the low-temperature environment. After the low battery alarm, the drone should be returned immediately for charging.

Use high temperature, Low-temperature resistant lithium batteries

In order to ensure the life and safety of the lithium battery, the protection management system (BMS system) is adopted in the battery pack of the high-temperature lithium battery to prevent overcharging, over-discharging, high-temperature operation, low-temperature charging, or short circuit, and even safety problem. Such as Himax fast-charge battery, the temperature will rise steadily during the fast charging process. The surface temperature of the fast charge battery must not exceed 65 degrees Celsius. During the fast charging process, the temperature will rise stably. The surface temperature of the battery will not exceed 65 degrees Celsius.

Other battery option: LiFePO4 Battery

In other application areas, like e-bike, camping portable power station, usually choose Lithium Iron Phosphate Battery (LiFePO4 Battery), also called LFP battery. It is a type of rechargeable battery. LiFePO4 technologies offer high-powered cell performance compatible with lots of lithium-ion application to deliver more power and extend life, also has these six advantages:

Good high-temperature resistance.

No memory effect

Higher-capacity compare with same size lead acid battery

Longer cycle life than other lithium-ion batteries

Good safety characteristics and Eco-friendly

Ideal drop-in replacement for lead-acid batteries

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