In the lithium battery module, several single cells are connected into a power supply in series and parallel through conductive connectors, and are fixed in the design position through the process and structure to play the function of power charging and storage. It can be said that the basic role of the module is to connect, fix and security protection. The connection mode between the cell and the module mother of the battery not only affects the manufacturing efficiency, but also affects the performance of the battery after loading. Lithium battery module can be understood as the intermediate product of lithium ion cell and pack formed by combining it in series and parallel mode. Its structure must play a supporting, fixed and protective role in the cell, which can be summarized into three major items: mechanical strength, electrical performance, thermal performance and fault handling ability. Whether the battery can fix the position of the cell and protect it from destructive deformation, how to meet the requirements of current carrying performance, and how to meet the control of the cell temperature, will be the standard to judge the quality of the lithium battery module. The whole process of lithium battery module design includes the objectives of module design, integrating the details of module design, and having a complete verification process of module design, including structure, electrical and cooling safety. The first part is divided into several design levels： To meet the demand characteristics of the vehicle is equivalent to the product, mainly divided into structural design, electrical design, thermal design, safety design, according to the requirements of the cell to give enough pressure, through a certain pressure can effectively prevent the expansion of the cell, in the life to give a certain support. The second part, the manufacturing process： The most important is the cell from the single to stacking, welding, sampling line layout, CMU layout, the whole process and equipment assembly have specific requirements. The third part, maintenance consideration： The first step is to make the product. In the later stage, with the use of the vehicle, the maintenance of the whole lithium battery module, especially the damage of the sub-parts inside, should be combined with the manufacturing process and maintenance process. Key points of lithium battery module structure design: Reliable structure of lithium battery pack: vibration resistance; Process controllable: no excessive welding, virtual welding, to ensure that the cell is 100% without damage; Low cost: promote the automation of PACK production line, including production equipment and production loss; Easy separation: lithium battery module is easy to maintain, repair, low cost, good use of battery cells; To achieve the necessary heat transfer isolation to avoid the rapid spread of heat runaway, you can also consider this step into pack design. The unique advantages of the BOSA lithium battery module： 1)  TUV, UL, UN38.3, MSDS, CCS certification;   2) The module has temperature and voltage sensor pre-welded with wiring to the BMS, connection with BMS is "plug and play" type; 3) The module is of standard design and mature manufacture which has 40K electric vehicle/100Mwh ESS and yachts application experience; 4) It's universal to all BMS, not limited to BMS types; 5) It's flexible in configuration, 8 Pcs cell could be 1P8S 25.6V, 2P4S12.8V; 6) Modules are connected by Busbar and bolts into battery system. It is understood that at present, the module composition efficiency of cylindrical cells in the industry is about 87%, the system group efficiency is about 65%; the module composition efficiency of soft package cells is about 85%, the system group efficiency is about 60%; the module composition efficiency of square cells is about 89%, and the system group efficiency is about 70%. At present, the square cell module is indeed an optimal choice.

Lithium battery is one of the most commonly used rechargeable batteries nowadays. Due to its small size, light weight, low power consumption and long life, it is favored and supported by many consumer electronics products, such as wireless earphones, smartphones, electric bicycles and notebook computers wait. The rise of new energy vehicles has also made the development prospects of lithium batteries very good. According to data, the global lithium battery market will reach 130 billion US dollars in 2025. With the development of sustainable cutting-edge battery technology and the requirements for battery energy density in different application fields, the future development prospects of lithium batteries are very promising. First of all, lithium batteries will be more used in the future. Since lithium batteries can quickly provide stable power output, they can be perfectly used in new energy vehicles, robots and mobile devices, which will greatly help energy conservation and emission reduction. Secondly, due to the small size, light weight, and long life of lithium batteries, lithium batteries have been used in aircraft and spacecraft in recent years to replace traditional aluminum oxide and nickel-manganese batteries and become the preferred battery for future spacecraft. Therefore, lithium batteries will be more developed in the future. In addition, lithium batteries have good recyclability. Compared with other battery types, lithium batteries are easier to recycle, making lithium batteries almost completely replicable, so they can effectively improve environmental pollution problems.   Finally, the future development of lithium batteries depends on the development and realization of new technologies, including high energy density technology and low temperature constant electrical signal technology. And new solutions to combat the safety, reliability and recyclability of lithium battery technology, among others.   To sum up, lithium batteries have strong development potential in the future because of their advantages of small size, light weight and long lifespan.

BOSA energy introduces its high voltage modules for ESS containers after 3 Gwh installation experience in China Market； “We only introduce mature products to overseas market”,introduced by Andy , marketing director of BOSA energy.  The HV modules are suitable for 1500V liquid cooling energy storage systems.“They are of smart design,we combined light weight technology,HV safety design and ventilation optimization technology”, “ simulation tools help with Mechanical strength and thermal design, they are of high efficiency and accurency ” introduces by Andy. Besides modules, the standard battery draw is one main product. The standard draw and cluster design makes efforts on product cost competitiveness and installation convenience； BOSA Energy would like to share its experience on ESS production and offer OEM service；   BOSA energy focuses on standard battery modules and battery system supplying. In last 15 years BOSA energy modules are working in over 30 countries in Europe, America,Australia etc, they are widely used on electric buses, trucks,forklift, utility vehicles,fleet retrofitting, electric yachts, home energy storage and industrial energy storage etc. 

BOSA LF304 cells and Modules are officially launched into overseas market，with 180Wh/kg energy density and 4000 cycles life, it has been widely used on electric buses and heavy electric trucks. The standard LF304 modules 12.8V 304Ah, 19.2V 304Ah, 25.6V 304Ah have got UN38.3 certificate for overseas market. They have passed the thermal shock, vibration, overcharge, over discharge,drop test etc, the rust and tidy design are well appreciated by partners.  BOSA energy focuses on standard battery modules and battery system supplying. In last 15 years BOSA energy modules are working in over 30 countries in Europe, America,Australia etc, they are widely used on electric buses, trucks,forklift, utility vehicles,fleet retrofitting, electric yachts, home energy storage and industrial energy storage etc.

1. Battery voltage (V) Open circuit voltage (OCV) Lithium battery is not connected to the external circuit or load voltage, generally with a multimeter can be tested. Operating voltage (WV) The potential difference between the positive and negative terminals of the battery under external load, i.e. when a current flows through the battery in the circuit. When the battery is working, there will be current flowing through the battery. Because of the internal resistance and load resistance of the battery itself, the operating voltage of the battery is always lower than the open-circuit voltage. Discharge cut-off voltage (DCV) : Refers to the battery in the case of electric energy, discharge to reach the set voltage, generally set voltage is 3.0V or above, overdischarge will have irreversible impact on the battery. 2.Battery capacity (Ah or mAh) Battery capacity refers to the amount of electricity released by the battery under certain conditions (discharge rate, temperature, termination voltage, etc.), which is one of the important indicators of battery electrical performance. It is expressed in C and expressed in Ah (ampere hours) or mAh (mah hours). Battery capacity (Ah) = Current (A) x discharge time (h). 1) Rated capacity That is, the capacity indicated on the battery packaging is the lowest capacity released under standard conditions according to the standards promulgated by the state or relevant departments. 2) Theoretical capacity The design is based on the mass of the active substance by Faraday's law calculation of the theoretical value. 3) Actual capacity According to the actual situation of the battery, under a certain charge-discharge system released battery capacity. It is related to the condition of the battery itself, such as SOC, SOH and so on, as well as the charge and discharge system. 3. Battery internal resistance (mΩ) The internal resistance of a battery is the resistance to flow through a current. Battery internal resistance is mainly affected by battery materials, production technology, battery structure and other factors. It includes ohmic internal resistance and polarized internal resistance: Ohmic internal resistance: depends on the composition of electrode material, electrolyte, diaphragm resistance, contact resistance between materials, and contact resistance with the housing. When a battery is discharged, the Ohm resistance obeys Ohm's law. Polarization internal resistance: it is mainly the electric resistance caused by the electrochemical polarization and the concentration difference polarization generated when the battery flows through the electric current. The polarization resistance increases with the current density, but is not linear, and often increases linearly with the logarithm of the current density. The internal resistance of a battery is not a constant and changes over time during discharge because the composition of the active substance, electrolyte concentration and temperature are constantly changing. 4. Charge Cycle life A secondary battery is called a cycle or a cycle. After repeated charging and discharging, the capacity of the battery gradually decreases. Generally, lithium batteries are required to charge and discharge under standard conditions. When the battery capacity is reduced to 80%, the number of cycles the battery experiences is the cycle life. Influencing factor: Improper use of batteries, battery materials, electrolyte composition and concentration, charge-discharge ratio, discharge depth (DOD%), temperature, and production process all affect the cycle life of batteries. 5. Energy density (Wh/Kg) Volume specific energy or mass specific energy refers to the energy released per unit volume or mass, usually expressed as volume energy density (Wh/L) or. Calculation formula: Volume Energy density (Wh/L) = Battery capacity (Ah) x average discharge platform (V)/ battery volume (L) Mass Energy density (Wh/kg) = Battery capacity (Ah) x Average discharge platform (V)/ Battery weight (Kg) 6. Battery charging and discharging depth (SOC, DOD) Charge depth: The ratio of charge to nominal capacity, usually expressed as SOC. Discharge depth: Discharge depth is the ratio of discharge capacity to nominal capacity. It is usually denoted by DOD. For example, if the capacity of a 20Ah battery is discharged, the capacity becomes 4Ah, which can be called 80%DOD. If the capacity of the battery after charging is 10Ah, the charging depth of 50%SOC can be used. 7. Charge and discharge ratio (A) Discharge rate: the current value required to discharge its rated capacity within a specified time, which is numerically equal to the multiple of the rated capacity of the battery. For example, if the discharge rate is 2C, the battery discharge current is 2 x the capacity of the battery (unit: A). Charge ratio: The rate at which the battery is charged, which is equal to the rated capacity of the battery. Classification of discharge rate: Low magnification rate (<0.5c), medium="" magnification="" rate="" high="" super="">7.0C). 8. Over discharge Battery in the discharge process, exceed the battery discharge termination voltage value, but also continue to discharge, it may cause the battery internal pressure rise, positive and negative active material reversible damage, so that the capacity of the battery significantly reduced. 9. Over charge When the battery is charged, if it continues to charge after it has reached the full state, it may lead to increased internal pressure, battery deformation, night leakage and other conditions, and the performance of the battery will be significantly reduced and damaged, or even dangerous explosion. 10. Load capacity When the positive and negative ends of the battery are connected to the electrical appliance, the output power that drives the electrical appliance to work is the load capacity of the battery. 11.Battery formation After the battery is assembled and injected, the positive and negative electrode active substances are activated through certain charging and discharging ways to improve the battery's charge-discharge performance, self-discharge, storage and other comprehensive performance. Only after the battery has been formed can its true performance be realized. At the same time, the separation process in the formation process can improve the consistency of the battery pack and improve the performance of the final battery pack. 12. Battery capacity In the process of battery production, due to the process and material itself, the actual capacity of the battery is impossible to be completely consistent, through a certain charge-discharge system detection, and the battery capacity classification process is called capacity separation. 13. Consistent battery pack A battery pack is composed of multiple cells connected in series and parallel. The overall performance and life of a battery pack depends on the poor performance of one cell, which requires high consistency of performance of each cell in the battery pack. For example, batteries of the same batch and model are screened by the consistency of voltage, internal resistance, capacity, and even charge-discharge curves to improve the consistency of the battery pack.

On Oct.15,a battery fire knocked out power at a key data center in South Korea,causing the country's two Internet giants,Naver and Kakao,to shut down services and severely affecting almost all sectors of the country,including finance and transportation. According to the South Korean police,the fire occurred near A lithium battery rack in the electrical room on the third floor of the basement of the data center.The power supply was stacked in five battery racks,and one of the lithium batteries sparked a fire before automatic fire extinguishing equipment was activated and sprayed with gas. The data center,jointly built by SK and IBM,will manage the data of key platform operators such as SK Telecom,Kakao,a social networking app,and Naver,a portal site.As a result,Internet services in South Korea were largely paralyzed after the fire broke out.Kakao's share price fell 4%to 5%as a result of the accident,wiping 2 trillion won(10.1 billion yuan)off its market value. The fire was put out eight hours later at around 11:46 p.m.Friday,police said.No one was injured,but all the batteries were destroyed in the blaze. Lithium battery fire incident occurred frequently in recent years,the battery safety problem has become one of the important issues of new energy electric vehicle,a well-known lithium battery fire is different from general fire,after a fire is very difficult to extinguish,along with the increasingly wide application of lithium batteries,combustion and explosion safety issues are development and application has been the battery to break through the bottle cap. Generally speaking,the direct cause of lithium battery fire explosion accident is the battery heat out of control.Cause thermal runaway,on the one hand is the cell itself has defects,on the other hand,by the external impact of heat release,will also lead to thermal runaway.Improving battery consistency is an important way to ensure battery string security and reliability. The common lithium-ion batteries on the market are basically divided into four categories,among which LiFePO4 battery has the best thermal stability,LiMn2O4 battery is the second best,LiNiCoMnO2 battery is slightly worse,and LiCoO2 battery has the worst thermal stability.LiFePO4 battery has long cycle life,small side effects,low cost,large charge-discharge ratio,good stability at high temperature,but relatively low energy density.LiMn204 battery cost is low,low toxicity,but poor thermal stability,short cycle life,less applications.LiNiCoMnO2 battery has high energy density,but the temperature increases after high-power charging and discharging,and the oxygen is released at high temperature.It has poor thermal stability and short life.