Energy saving has become an important issue in the global.More and more electric vehicles have been come out.Such as electric vehicles,electric buses,electric skateboards.
In recent years, underwater sports have turned into the popular lifestyle.
Some popular underwater sports products come out such as underwater drones,electric surfboards,jet skis,electric swimming rings,electric remote ,control lifebuoys ect which match with a powerful battery system.Not only the battery should be with strong life cycles but also need one accurate SOC power metering function.
The whole battery should have waterproof IP68 in 50m-100m.In addition,one stable and reliable communication protocol (UART/RS485/Canbus) is required to be connected to the host to ensure personal safety and equipment reliability.
The design idea of our underwater battery is the inheritance of the long term historical experience of the design and production for plenty of industrial which require best battery construction,safety and reliability and extremely waterproof function.
The development and testing process of our surfboard battery pack as below:
BMS design solution:
-The intelligent balance process of the cells and the balance voltage can be flexibly adjusted by the upper computer
By charging and discharging,the SOC data is recorded by the BMS at the same time,and the final discharge electric power can confirm whether the BMS SOC calculation is accurate by the discharge data and the SOC data
The BMS Specification:
How to test the battery pack waterproof function?
We can the testing equipment for waterproof testing.
设置参数 Data Setting
压力控制方式 Pressure control method
自动调节 Automatic adjustment
压力误差值Pressure error value
传感器显示精度Sensor display accuracy
试验水深Test water depth
压力设置 Pressure setting
安全阀排气压力 Safety valve discharge pressure
测试时间设定 Test time setting
360 min/120 min
Test data underwater:
Test water depth
Underwater testing data:
The following is the test results which include information about Series No., Testing Content, Water Depth of Testing, and Testing Time.
1 43.2V35Ah 2 meters 360minutes PASS
2 43.2V 35Ah 5 meters 180 minutes PASS
In terms of waterproof battery pack solution，special attention should be paid to the following tips:
Choose the suitable waterproof glue
Professional waterproof design like perfect housing construction,LED display materials
The connector which should be IP68 grade and the connector support A discharge current
BMS design,and choose the competitive cells for the battery pack solution
Control the production with good figure
Use the equipment to test the battery pack
We have gained rich experience from testing ,research and development. If you are looking for custom battery pack solution, feel free to contact us!
There are two classification of the performance, one is storage low temperature li-ion battery, another is discharge rate low temperature li-ion battery.
Low temperature energy storage lithium battery is widely used in military PC, paratrooper device, military navigation instrument, UAV backup start-up power supply, special AGV instrument , satellite signal receiving device, marine data monitoring equipment, atmospheric data monitoring equipment, outdoor video recognition equipment, oil exploration and testing equipment, railway along the monitoring equipment, Power grid outdoor monitoring equipment, military heating shoes, car backup power supply.
Low temperature discharge rate lithium battery is used in infrared laser equipment, strong light armed police equipment, acoustic armed police equipment.
Low temperature lithium battery is divided into military low-temperature lithium battery and industrial low-temperature lithium battery from the application.
0.5C discharge performance test report
One 18650-2200mah cell discharge performance under -20℃ and -40℃
1.testing machine：Neware automatic battery test system，Chf constant temperature and humidity test cabinet。
2.Battery performance：low temperature li-ion battery 18650CL-2200mAh
First,when the temperature is 20℃ ,the battery is charged with 5C current to 4.2V and discharged with 0.5C current to 2.5V.
Second,when the temperature is 20℃ ,the battery is charged with 0.5C current to 4.2V，and the temperature is -20℃,discharged with 0.5C current to 2.5V.
Third,when the temperature is 20℃ ,the battery is charged with 0.5C current to 4.2V，and the temperature is -30℃,discharged with 0.5C current to 2.5V.
Four,when the temperature is 20℃,the battery is charged with 0.5C to 4.2V，and the temperature is -40℃ ,discharged with 0.5C current to 2.5V.
5.More details, you can see from test diagram
20℃ test diagram
-20℃ test diagram:
-30℃ test diagram:
-40℃ test diagram:
Low temperature li-ion battery is used for special industry with limit working environment.
With recent technological advances, engineers had to find an optimal way to power their innovative creations. Automated logistic robots, electronic bikes, scooters, cleaners, and smartscooter devices all need an efficient power source. After years of research and trial and errors, engineers decided that one type of battery system stands out from the rest: the smart battery management system (BMS). The standard BMS battery has a lithium anode and boasts a level of intelligence similar to a computer or robot. A BMS system answers questions like, “How could the logistic robot know it’s time to recharge itself?” What sets a smart BMS module apart from a standard battery is that it can assess its power level and communicate with other smart equipment.
What Is a Smart BMS?
Before defining a smart BMS, it’s important to understand what a standard BMS is. In short, a regular lithium battery management system helps to protect and regulate a rechargeable battery. Another function of a BMS is to calculate secondary data and then report it afterwards. So, how does a smart BMS differ from a run-of-the-mill battery management system? A smart system has the ability to communicate with the smart charger and then re-charge itself automatically. The logistics behind a BMS helps to prolong the battery’s life and maximize its functionality. Just like a regular device, a smart BMS relies heavily on the smart system itself to keep it functioning. To achieve maximum functionality, all of the parts must work together in sync.
Battery manager systems were initially (and still are) used in laptops, video cameras, portable DVD players, and similar household products. After the increase use of these systems, engineers wanted to test their limits. So, they began to put BMS electric battery systems in electric motorcycles, power tools, and even robots.
The Hardware and Communication Sockets
The driving force behind a BMS is the upgraded hardware. This hardware permits the battery to communicate with other parts of the BMS, such as the charger. Moreover, the manufacturer adds one of the following communication sockets: RS232, UART, RS485, CANBus, or SMBus.
Here is a look at when each of these communication sockets come into play:
Lithium battery pack with RS232 BMS is usually used on UPS in the telecom stations.
Lithium battery pack with RS485 BMS is usually used on solar power stations.
Lithium battery pack with CANBus BMS is usually used on electric scooters, and electric bikes.
Ltihium battery pack with UART BMS is widely used on electric bikes, and
And In-depth Look at a Lithium Electric Bike Battery with UART BMS
A typical UART BMS has two communication systems:
Version: RX, TX, GND
Version 2: Vcc, RX, TX, GND
What’s the Difference Between the Two Systems and Their Components?
BMS controls and systems achieve data transference through TX and RX. TX sends the data, while RX receives the data. It’s also crucial that lithium ion BMS has GND (ground). The different between GND in version one and two is that in version two, the GND is updated. Version two is the best option if you plan on adding an optical or digital isolator. To add either of the two, you will Vcc, which is only part of the UART BMS’ version two communication system.
To help you visualize the physical components of a UART BMS with VCC, RX, TX, GND, we have included the graphical representation below.
What sets this li ion battery management system away from the rest is that you can monitor it in real time. More specifically, you can find the state of charge (SOC) and the state of health (SOH). However, you won’t see get this data by just looking at the battery. To pull the data, you need to connect it with a specialized computer or controller.
Here is an example of a Hailong battery with UART BMS. As you can see, the communication system is covered by an outer battery protector to ensure safety and usability.
With the help of battery monitoring software, reviewing the battery’s metrics in real-time is rather easy. You can use an USB2UART wire to connect the battery your computer. Once its connected, open the monitoring BMS software on your computer to see the specifics. Here you will see important information like the battery capacity, temperature, cell voltage, and more.
Choose the Right Smart BMS For Your Device
Give the number of battery and BMS manufacturers, it’s vital to find the ones offering high-quality batteries with monitoring tools. No matter what your project requires, we are happy to discuss our services and the batteries we have available. If you have any questions regarding smart battery management systems, don’t hesitate to contact us. We will offer you only the best smart BMS system and are ready to help you find the right one for your needs.
If you own a remote-control gadget or an electric vehicle, your main sources of power come from the battery pack. In short, battery packs are rows of lithium, lead acid, NiCad, or NiMH batteries that are bundled together to achieve maximum voltage. A single battery only has so much capacity – not enough to power a golf cart or hybrid vehicle. Wholesale battery pack manufacturers have processes in place to make sure each battery meets the voltage requirements and is safe for use. If you have a device that requires a high-capacity battery, custom battery pack design is offered by many Chinese manufacturers.
What is Battery Pack Assembly?
Battery pack assembly is when multiple cylindrical lithium-ion batteries are connected parallelly to form one uniform pack using a nickel strap as the connecting mechanism. Technicians work in a line where they carefully form the pack piece by piece. Battery pack manufacturers in China merge the custom lithium batteries into a single unit using either multi-row, face-centered cubic, or an alternating row design. Once the batteries are combined, battery pack assemblers wrap them in heat shrink or another form of covering.
What Kind of Team Should the Leading Battery Pack Manufacturers Have?
A custom battery pack manufacturer needs an experienced and highly-qualified team to produce durable and long-lasting battery packs. Depending on the exact position, personnel should hold several years of experience in the custom lithium-ion batteries industry and hold a license or college degree. Here’s a look at the team a leading battery pack manufacturer should have:
The Engineering Team
Every manufacturer needs an engineering director to lead the team. The director should have over fifteen years of experience designing battery packs for multiple industries and be familiar with battery pack production for robotics, hybrid vehicles, gardening and power tools, e-bikes, and electric surfboards. A qualified director needs to have a strong knowledge with battery management systems (BMS) design such as SMBUS, R485, CANBUS, and other devices that manage electronic battery systems.
There should be a project engineer that works underneath the engineering director. Projects engineers should have ten years of experience in the field and extensive knowledge about nickel strap, lithium metal oxides, the chemical material of each cell, and how to effectively maintain the welding temperature to create the optimum custom battery charge. Lastly, the project engineer for should look for deficiencies in the production process and suggest areas of improvement.
The last crucial member of the engineering team is the construction engineer. Like the project engineer, the construction engineer needs at least ten years of experience in the field, especially in the area of designing custom battery casings and moldings. With their molding experience, they should help the production reduce the cost of goods sold (COGS) by eliminating waste and the numbers of errors during manufacturing. Lastly, the construction engineer needs to control the quality of the battery casing achieved through mold injection process.
The Quality Assurance Team (QA)
Every battery pack manufacturer needs a QA team to test the li-ion batteries to make sure they meet quality standards. The QA chief needs at least five years of experience of using web-based applications to test both prototype and production models of battery packs.
The TLH Battery Production Procedure:
The flowchart above illustrates the production cycle of the TLH battery from procurement of materials all the way to the final testing and shipment of the battery. All custom rechargeable battery packs undergo a full-on QC inspection and a visual inspection to make sure it meets requirements. Lithium-ion pack wholesale manufacturers also inspection the BMS functionality along with the welding job before actually installing the battery pack. From the beginning to the end, each step is crucial to producing high-quality battery packs. The QA team carefully looks at each battery pack and returns them as defective if any problem is found.
Considerations for Ordering a Battery Pack
Before purchasing a battery pack for your own use or resale, there are several components to consider:
The Cell Brand
The longevity of your battery and the capacity depends on the cell brand. For example, Panasonic and Samsung cells have high capacity but come at an additional cost. This is an important component if your device needs a lot of power.
If you’re buying an electric motorcycle battery pack or a battery for your power tool, you’ll get a better price the higher your MOQ is. All lithium battery pack wholesale manufacturers offer quantity discounts.
You need to thoroughly inspect the design before ordering a battery pack to make sure it will fit in your device. If it doesn’t, the manufacturer should be able to customize it, so it fits perfectly.
No matter how much voltage you need to power your tool or vehicle, a trustworthy battery pack manufacturer can meet your needs. Chinese manufacturers are some of the best producers of custom lithium-ion packs along with various other types of batteries.
Making battery packs in parallel by modular solution
The existing problems when two or more battery packs are in parallel:
High voltage battery packs automatically chare the low voltage of the battery packs. At the same time, the charging current becomes very large and even fluctuates as every single battery pack has different internal resistance, voltage and capacity, which might damage the BMS.
At present, most companies use current-limited modular to control charge current for each battery packs. However, this is potential to damage the BMS.
Current-limited modular allows the BMS on protection when the charge current is large. Therefore, the all-power system cannot discharge and charge.
If the battery packs modular are applied to electric motorcycle, ebike, robot, telecom storage, they are not convenient to replace one battery pack of the modular.
The TLH battery team designed one parallel modular. More details of our parallel modular are as summarized below:
Our parallel modular supports two or more battery packs and works simultaneously. The user can use one battery pack or more battery packs at any time.
The continuous discharge current is no more than 100A of battery pack modular.
The voltage is no more than 110V of battery pack modular.
Our parallel modular can support CANBUS and RS485 communication. However, each battery pack should have a unique ID.
Our parallel modular is widely used for shared electric bike, electric motorcycles, mobile storage equipment and portable cleaning equipment, among others.
Working mode of our parallel modular
Charge mode: The lower capacity battery pack will be charged in priority. When the voltages of the two battery packs or one battery pack are same, the current distribution ratio is equal to the battery capacity ratio. For instance, a 40Ah battery is parallel with a 60Ah battery pack as the 40Ah battery pack accounts for 40% of the charger’s output power while the 60Ah battery pack accounts for 60% of the charger’s output power. The charging current range for each battery is 0-50A whereas the dual battery is 0-100A.
Discharge mode: High voltage battery pack will give discharge in priority. When two battery packs voltage are equal to two batteries simultaneously to the load discharge, the current distribution ratio is also considered to be equal to the battery capacity ratio. For instance, a 40Ah battery in parallel with a 60Ah battery pack where 40Ah battery packs account for 40% of the load input power while the 60Ah battery pack accounts for 60% of the load input power. Accordingly, the discharge current range for each battery is 0-150a while the dual battery is 0-300a.
Three batteries parallel system introduce D1,D2,D3,D4,D5,D6 for fixed the current direction. Thus, BAT1, BAT2,and BAT3 are independent.
However, the Diode has a drop voltage VF as shown in the Figure below.
The larger the current, the larger the voltage drop. Also, larger drop of voltage will cause power loss. Moreover, the temperature will up. Higher temperature influences our system and the Li-battery.
Therefore, we use the NMOSFET instead of the diode. In addition, the NMOSFET is need to a control unit. We turn on the NMOSFET when Vin > Vout and turn t off when Vin < Vout.
The NMOSFET drop voltage = ID*RDS. We need to choose a low RDS NMOSFET if we want less power loss. The control frame is shown in the Figure that follows.
Welcome to discuss with our R&D team about the parallel modular!
Pack is the process of assembling a lithium battery cell, which may be a single battery or a serial-parallel battery module. The spot weld process is important in the entire battery pack process.
Battery pack assembly involves 18650 cells, spot weld, PCB or BMS weld, bracket, and fish paper. However, the spot weld process is the core for battery pack assembly.
The spot weld process causes certain quality problems:
1. The nickel straps are overlapped in the process of welding (as shown in picture B). This cause the spot weld to be unstable and burnt. Finally，it will cause uneven resistance of each battery.
2. The spot weld over three times. Resistance weld is the need to weld the parts in connect pot and through the large voltage, high current, in contact with high heat for the parts of the contact with the local melting, and cooling after welding in overall. The battery pack causes an internal construction breakdown and leakage after multiple spot welds.
3. When the battery pack is in the spot weld, some battery pack manufacturers use single nickel straps (as shown in A-point and D-point). In addition, single nickel process causes battery pack different internal resistance.
The battery pack is charged and discharged throughout, causing the voltage gap because of internal resistance gap. After the charge and discharge cycles, it will reduce the life cycle as well.
Besides, when the battery pack works with the large discharge current, the nickel strap will be burnt.
4. There is no guide hole nickel strap (as shown in the B-point). The effect of no diversion hole is that when the spot weld machine flows rapidly to the cell, it will cause cells breakdown and even leakage
5. When the battery packs are in series and parallel, it is crucial to control each cell’s connection. This helps to avoid fake spot weld and reduces internal resistance. At the same time, it will reduce heating when the battery pack is operational. Also, when the battery pack works at the stable temperature, it will increase the life cycle.
Why is it important to calculate the remaining battery capacity as accurately as possible?
The use of the cleaning system, robot, military equipment, medical equipment has been found useful in the modern age. Also, measuring instruments such as portable devices (for example, the universal make up) has been found to align with the trend of development. However, lots of development has not been noticed because all portable devices need to be powered by a battery
The battery can be said to be the most difficult parts of the supply chain whenever there is a need to predict the remaining running time of the system. As a result of a continuous increase in the number of portable application, there is a need to achieve more critical operations such as the use of mobile phone for account management; medical equipment must be fully deployed for the monitoring of essential data
The methods for monitoring the battery capacity
Nowadays, the monitoring methods used are of two types. The first type is on the current integral (current integration) while the second type is based on the voltage measurement. The former is based on a sound idea which implies that whenever the battery is fully charged, there is an incidence of flow of discharge. In this case, one can get the amount of residual capacity. The current integration method works very well when the battery is newly recharged and is known to be fully charged.
This method has been successfully used in many current battery monitoring processes.
The weakness of monitoring the battery capacity through current integral
It is important to stress that this method is limited in one way or the other. One of its weaknesses is the non-functionality of the battery in the use mode. Whenever the battery has not been used for several days after charging, or if a few recharge and discharge cycles are not fully charged, the self-discharge caused by the internal chemical reaction will become apparent. Since there are no ways or methods to self-discharge, then the best way to correct it is through a predefined equation. Different battery models have different self-discharge speeds, depending on the charging state (SOC), temperature, and the battery charge/discharge cycle history and other factors. Creating an accurate model of self-discharge takes a considerable amount of time to collect data, even though it does not guarantee the accuracy of the results.
Another challenge with this method is that it is only possible to update the total power value whenever it is completely discharged immediately after full charging. If the number of complete discharges during the battery life period is deficient, the real capacity of the battery may have begun to decline significantly before the actual battery value is updated by the meter. Therefore, it causes the monitoring it to overestimate the amount of energy available during these cycles.
Even if the battery charge is updated at a given temperature and discharge speed, the available power will change with the discharge speed and temperature changes.
Monitoring the remaining capacity through voltage
One of the first methods is the voltage based method. It only needs to measure the voltage between the two levels of the battery. The method is based on a known relationship between the battery voltage and the remaining charge. It looks simpler, but it has lots of difficulties in the monitoring process. The simple connection between the battery voltage and the power is present only when no load is applied during the measurement. When the load is applied (this happens in most cases where the user is interested in the capacity), the battery voltage is distorted by the pressure drop caused by the internal impedance of the battery. Also, even if the load is removed, the (Relaxation process that occurs on the battery can cause a continuous change in voltage within a few hours. As a result of several reasons, the pressure drop correction method based on the knowledge of battery impedance is still problematic.
1.Chemical reaction and the voltage change of battery
2.The complex electrochemical reaction of the battery itself causes its transient voltage response.
3.The primary steps of charge transfer from the electrodes of a lithium-ion battery (the steps of other batteries are similar).
The charge must first pass through an electrochemically active material (anode or cathode) storing energy in the form of electrons, which is stored in the electrolyte in the form of ions after reaching the surface of the particle. These chemical steps are related to the time constant of the battery voltage response.
The battery voltage will decrease over time at different rates and gradually increase after the load is removed. The voltage relaxation of the lithium-ion battery after the load is applied under different charging states.
With the knowledge of the error of the voltage based battery monitoring, we assume that the load voltage can be corrected by subtracting the IR pressure drop and then obtaining the current SOC through the use of corrected voltage value. The first problem to be encountered is that the R-value depends on the SOC. If the average value is used, then in almost complete discharge state (at this time the impedance is more than ten times the state of the charge). The estimation of the SOC error will reach 100%. One way to solve this problem is to use a multiple voltmeters based on the SOC under different loads. Impedance also depends largely on the temperature (temperature per reduction 10°c, impedance increases by 1.5 times). This interaction should be added to the table, and this makes the calculation process extremely difficult.
The characteristics response of the battery is transient. The implication of this is that the effective R-value depends on the load time and it is evident that we can treat the internal impedance as an ohm resistor without considering the time factor. This is because even if the correlation of R and Soc is taken into account in the voltmeter, the change of load will lead to serious error. Since the slope of the SOC (V) function depends on the SOC, the range of transient errors varies from 50% in the discharge state to 14% in the charging process.
The variation of impedance between different batteries increases the complexity of the situation. Even the newly produced batteries will have a ±15% low-frequency DC impedance changes, which makes a big difference in high load voltage correction. For instance, in the case of the usual 1/2c charge and discharge current, 2Ah battery typical DC impedance is about 0.15ω, the worst will produce a 45mV voltage difference between the batteries, and the corresponding SOC estimation error is 20%.
Finally, when the battery is aged, an impedance-related maximum problem arises. It is well known that the increase in impedance is significantly lower than that of the battery. The typical lithium-ion battery has 70 charges and discharge cycle, DC impedance will be increased by one time, and the same cycle of zero loads will only drop by 2%~3%.
The voltage-based algorithm seems to work well for the new battery pack, but if the above factors are not taken into consideration, a fatal error (50%) is generated when the battery pack reaches 15% of the service life (the estimated 500 charge and discharge cycles).
Monitoring of the Battery: Current Method and Voltage Method
TI capitalises on the potentials of the current method and voltage method in the creation of next-generation power monitoring algorithm. The company has cautiously considered this seems natural, but hitherto involved scheme: combining current and voltage methods to use the most prominent method in different situations. As a result of the precise correlation between open circuit voltage and SOC, this method can achieve correct SOC estimation without load and power supply in relaxation state. Furthermore, the method also makes it convenient to find the exact “starting position” of the Soc by utilising the non-working period (any battery-powered device will have a working period). This method discards the need for self-discharge correction in the absence of a working period, as the device can recognise the precise SOC when it is connected. When the device is in operational mode, and the battery is loaded, the current integration method is alternatively used. The method does not require complex and imprecise compensation for pressure drop under load since the Coulomb meter number (coulomb-counting) has been tracking the changes of the SOC from the beginning of the process.
Can this Method Also be Used to Update the Charge Completely?
Yes! The method can be used to update the charge. Depending on the percentage of the SOC used before the load, the SOC after the load (both are obtained by voltage measurements in a relaxation state), and the amount of charge transmitted between the two. Therefore, there is easy determination of the total power that corresponds to the SOC change in the case of a specific charge change. However, this can be achieved in spite of of-the amount of transmission, the starting condition (without full charge).
This eliminates the need to update the charge under some special considerations. Thus it helps in mitigating another weakness of the current integration algorithm. This method does not only proffer a solution to the challenges of SOC, but it also avoids the effect of battery impedance, and it is used to achieve other purposes. This method allows you to update the total amount of power that corresponds to the “no-load” condition, such as the maximum possible charge that can be used. As a result of the reduction in IR, the power under zero load will also reduce, and the time to reach the end-voltage value is reduced when the load occurs. If the impedance relationship between the SOC and the temperature is known, there is a possibility to determine when the terminal voltage can be reached under the observed load and temperature based on a simple model.
Nevertheless, as mentioned earlier, the impedance depends on the battery and increases rapidly as the battery ages and the charge and discharge times increase. Therefore, storing it in the database is of no importance. In an attempt to provide a solution to this challenge, TI has designed a type of IC which can realise real-time impedance measurement, while real-time measurement can keep the database continuously updated. This offers a solution to the differences between the impedance of the battery and the ageing of the battery. The constant updating of impedance data makes it possible to predict the voltage situation under the specified load accurately.
In several scenarios, the method can be utilised to facilitate the reduction of the estimated error rate of electricity consumption to less than 1%, and, most importantly, to achieve high accuracy throughout the life cycle of the battery.
Another advantage of the adaptive algorithm is Plug and play. The implementation of the algorithm does not need to describe the relationship between impedance and Soc and temperature of the database, because this data will be obtained through real-time measurement. The database for self-discharge correction is no longer needed, but there is still a need to define a database of open circuit voltages and SOC (including temperature) relationships.
However, this relationship is obtained by the chemical properties of the positive and negative polar system, and not by the specific design factors of the battery model (e.g. electrolyte, separator, the thickness of active material, and additive). Since most battery manufacturers use the same active materials (LiCoO2 and graphite), their V (soc,t) relationships are the same.
Whenever the voltage of the batteries manufactured by different manufacturers especially in cases of zero load is compared, it can be inferred that their voltage value is very close to the deviation of 5mV. Also in the worst case scenario, the SOC error is only 1.5%. The development of a new battery necessitates the creation of a new database, unlike the hundreds of databases that are now used for different battery models. This ensures the implementation of the Power meter solution in different devices and the database does not rely on the batteries used. It is not necessary to reprogram even the batteries manufactured by different manufacturers. In this way, the realisation of the battery monitoring IC Plug and Play precision and reliability also improved accordingly.
In the battery industry, Li(NiCoMn)O2, having multiple advantages of the rapid occupation of the market, is gradually replacing the conventional lead-acid batteries.
With respect to the conventional battery, Li(NiCoMn)O2 possesses a long life, in addition to energy efficiency, eco-friendliness, low maintenance costs, full charging and discharging, light weight and numbers of other benefits. Briefly speaking, how many lifecycles a does a Li(NiCoMn)O2 battery have?
What is Li(NiCoMn)O2?
Naturally, li ion is a light metal with a small atomic mass*, together with the atomic weight of 6.94 g/mol, ρ = 0.53 g/cm3. Li ion is chemically active as well as convenient to lose electrons to be oxidized to Li+. Accordingly, the standard electrode potential is *negative, -3.045V, and the electro chemical equivalent * is small, 0.26g/Ah. These characteristics of lithium figure it out that it is a kind of quite a high-energy material. The ternary lithium battery refers to a lithium secondary battery that makes use of three types of transition metal oxides of nickel, cobalt and manganese as a positive electrode material. It fully integrates the good cycle performance of lithium cobaltate, in addition to the high specific capacity of lithium nickelate, and the high safety and low cost of lithium manganate. It synthesizes nickel with the help of the molecular level mixing, doping, coating and surface modification. A multi-element synergistic composite lithium intercalation oxide, for instance, cobalt manganese, is a lithium ion rechargeable battery having been extensively investigated and applied.
Li(NiCoMn)O2 cycle life
The li(NiCoMn)O2 lifecycle implies that, following the use of the battery for a period of time, the capacity is attenuated to 70% of the nominal capacity (room temperature 25 ° C, standard atmospheric pressure, and battery capacity discharged at 0.2 C); besides that, the end of life can be considered as well. In the industry, the lifecycle is generally calculated by the number of cycles in which the lithium battery is fully charged and discharged. All through the mechanism of use, irreversible electrochemical reactions take place inside the lithium battery, which result into a decline in the capacity, for instance, decomposition of the electrolyte, deactivation of the active material, collapse of the positive and negative structures, and reduction in the number of lithium ion insertion and deintercalation. Moreover, experiments have shed light on the fact that higher rate of discharges lead to faster attenuation of the capacity. If the discharge current is lower, the battery voltage is expected to reach the equilibrium voltage, together with releasing more energy.
The theoretical life of a Li(NiCoMn)O2 is approximately 800 cycles, which is medium in the commercial rechargeable lithium batteries. Lithium iron phosphate is approximately 2000 times, and lithium titanate is suggested reaching 10,000 cycles. Currently, the cell manufacturers promise more than 500 times in the Li(NiCoMn)O2 specifications produced by them (charge and discharge under standard conditions). Nevertheless, following the assembly of the batteries into the battery packs, owing to the consistency issues, voltage and internal resistance primarily cannot be exactly same, and its cycle life is approximately 400 times. The battery pack manufacturer recommends the SOC as 10%~90%. It is not recommended to carry out deep charge and discharge. Or else, it is expected to cause irreversible damage to the positive and negative structures of the battery. In case of its calculation by shallow charge and shallow release, the lifecycle is at least 1000 times. Together with that, if the lithium battery is usually discharged at a high rate and high temperature environment, the battery life will be greatly lowered to less than 200 times.
Life cycles of lithium battery are based on both the battery quality and material.
The number of Li(NiCoMn)O2 is approximately 800 cycles.
The number of cycles of lithium iron phosphate battery is approximately 2,500 times.
The number of genuine battery and defective battery cycle is different; the original battery is designed and produced in accordance with the number of cycles on the battery manufacturer’s specification book, and the number of defective battery cycles are not likely to be 50 times.
The material with comparatively more balanced capacity and safety manifests better cycle performance in comparison with the normal lithium cobaltate. Its nominal voltage is merely 3.5-3.6V in the early stage owing to the technical reasons. Nevertheless, there are restrictions on the scope of use, but until now, with the formulation with the continuous improvement as well as perfect structure, the nominal voltage of the battery has reached 3.7V, and the capacity has reached or exceeded the level of lithium cobalt oxide battery.
The popularity of electric bikes or e-bikes has increased drastically in the last couple of years. More and more people use this transportation method to get to shops, workplace or home quicker and with less effort. One of the most important components of an e-bike is the battery as this element dictates its speed and range. Since e-bikes are quite different one from the other, their batteries are also different too. Finding the best battery solution is essential to maximize the speed and range of a particular e-bike.
E-bike battery types
There are several types of integrated ebike batteriesone can use to power his electric bike. They have different pros and cons and are priced differently. Here are the most important ones.
Lead-acid batteries(SLA) – these are some the most popular types of batteries and they are commonly used worldwide. Although they are very cheap, they don’t last much, weigh up to three times more than lithium-ion batteries and are quite sensitive to external factors.
Nickel-cadmium batteries– these batteries hold more power than lead-acid batteries, but they are more difficult to dispose of safely and are also very sensitive. As a result, every battery supplieris trying to eliminate them from their product list and offer more environmentally-friendly and efficient options such as lithium-ion batteries.
Lithium-ion batteries – one of the most popular types of e-bike batteryconsists of lithium-ion batteries which can be found virtually anywhere – in a smartphone, tablet, smartwatch, portable speaker, etc. These batteries hold the most power, are less heavy, can be fitted to almost any device, and are increasingly cheaper.
As a drawback, lithium-ion batteries need to be properly packaged and controlled by integrated circuits to prevent overheating and fire. However, most e-bike battery suppliers take the required safety precautions to design a safe, high-quality lithium-ion battery which can be used on every e-bike.
Understanding the basics of e-bike batteries
To determine what type of custom e-bike battery is required for a particular electric bike model, one should first learn the main characteristics of a lithium-ion e-bike battery.
Amps and volts
Each e-bike battery features a certain number of volts and amps such as 24 volts and 10 amps, etc. These numbers represent the electrical power of the battery. The number of volts is usually associated with actual power (or horsepower), so the more volts, the greater weight an e-bike battery can pull and the faster it can go. Companies which look for batteries for e-bikes and are interested in power above everything else should ask for custom batteries featuring a high voltage such as 48V or even 52V.
On the other hand, the number of amps (or ampers) is usually associated with range, so the more it has, the greater distance an e-bike can travel. Companies which are interested in providing the longest range for their e-bike line should ask for a custom battery with high amperage such as 16 amps or 20 amps.
It is important to mention here that if a battery has a high voltage and amperage, it might also be heavier and larger. E-bike companies need to find the perfect balance between size/power before working with a battery manufacturer to design a custom e-bike battery.
This one is self-explanatory, it represents how many times a battery can be completely charged throughout its lifetime. Most batteries can be charged up to 500 times, but other models can be engineered to sustain up to 1,000 cycles.
Most e-bike batteries can be crafted to function efficiently at a charging temperature between 0 degree Celsius and 45 degree Celsius (32-113 degree Fahrenheit). The discharge operating temperature can be between -20 degree Celsius and 60 degree Celsius (-4 to 140 degree Fahrenheit). Batteries can be crafted to resist in various weather conditions and this should be specifically mentioned by the inquiring e-bike company.
Size and weight
The size and weight of an e-bike battery are also important. Ideally, e-bike batteries should be as light and small as possible while packing the most electric power. For example, most e-bike batteries can weigh about 3.7 kilograms or 8 pounds. Larger models can increase the range and speed of the e-bike, so if a manufacturer is interested in providing the fastest electric bikes on the market, it might need a bigger e-bike battery.
Case material and color
The material from which the e-bike battery is made is also important. Most models are made using aluminum alloy because this type of material is light and durable. However, e-bike battery manufacturers also offer other casing options such as plastic or ceramic. When it comes to color, most batteries are black, but custom colors can be ordered as well.
Understanding the process of crafting a custom e-bike battery
Making a brand new battery from scratch is not an easy task, but not an impossible one either. E-bike companies should work with specialized firms run by experts with years of experience when it comes to developing batteries. As mentioned earlier, it is paramount to make lithium-ion batteries as safe as possible, to prevent overheating and even fires.
First of all, e-bike companies should contact research and development teams and give them more details about their needs. Knowing the specifics of the e-bike which is going to use the battery is important, so providing as many details as possible is the right thing to do. These details include the desired speed of the e-bike, range, overall weight, shape of the battery as well as cycle times.
Today’s battery makers use sophisticated computer systems and design techniques to envision the new battery and give it a rough outline. At the request of the e-bike company, they can make the battery completely waterproof. This prevents the battery from developing electrical problems if one rides his e-bike through the rain.
Once the design and shape of the battery are established, the professionals will work on integrated circuits and delicate electronics to ensure the safety of the new battery model. Using state-of-the-art 3D designing tools, experts can come up with a brand new battery in a matter of weeks. Most e-bike batteries can also be equipped with a Deep Sleep function which helps conserving power and makes the battery run more efficiently.
Today’s lithium-ion batteries also come up with a plethora of safety systems which prevent overcharge, overheating, short circuits, excessive discharge, and other types of unwanted electrical faults. This is one of the most important stages in the manufacturing process. These protection systems make the battery safe to use for years and give more peace of mind to the customer who eventually buys the e-bike and uses it regularly.
After the electronics have been designed and put into place, it is time to find good casings for the battery as well as figuring out its final color. The experts work closely with the staff of an e-bike company to come up with an accurate casing that fits an electric bike perfectly. Most casing materials include aluminum alloy, plastic or ceramic.
When it comes to choosing the color, there are usually two options – use a neutral color for the battery (black, for example), or making it match the overall color of the e-bike, for a seamless design. The e-bike company which requested the manufacturing of the battery can have a final word here. The color options for a custom e-bike battery include but are not limited to red, blue, yellow, orange, purple and green.
When the battery is ready, it will be tested in various weather conditions, at various speeds and for different periods of times. The testing procedure is extremely thorough, pushing the e-bike battery to the limits to ensure that it can handle any real-life situation with ease. If certain scenarios make the battery behave improperly, the specialists go back to the drawing board to improve the e-bike battery.
Once the battery has passed the final tests at the factory, it is delivered to the e-bike company for additional testing and eventually put into production. Professional battery manufacturers offer a warranty period of at least 12 months for each e-bike battery they make. This gives the customer an assurance that his investment is protected and builds trust with the e-bike company.
Crafting a brand new battery from scratch is not an easy job, especially when there are a lot of safety protocols required for a proper design process such as BMS or Smart BMS as well as UART, CANBUS or SMBUS. It is paramount for an e-bike company to work with a professional battery manufacturer which can tailor its services according to the needs of its clients.
At TLH battery, we specialize in lithium-ion batteries and custom battery packs for electric bikes. Our professionals have more than 10 years of experience in this industry and we go the extra mile to ensure that the batteries we make are safe to use in all weather conditions. We serve customers from countries such as Germany, France, Italy, USA, Canada, and more. If you are interested in a custom e-bike battery solution, contact us today and let our experts help you!