Reliable lithium iron battery design for e-skateboard

Advantages of lithium-ion battery for electric vehicles, the cooling ability of lithium-ion battery for electric vehicles. Lithium-ion batteries are relatively light, easy to carry around and have a relatively long life. There are a variety of lithium-ion battery electric vehicles available today. Giant, TaiXiang, Jemma, Ardi and Emma are all good choices. Under the condition of high temperature, if there is no appropriate cooling method for electric vehicle lithium-ion battery, the temperature of the battery pack will vary greatly, which will affect the consistency of the battery monomer and cause a series of subsequent problems.Advantages of lithium-ion batteries for electric vehicles● Powerful powerLithium-ion batteries for electric cars climb hills faster than lead-acid batteriesLow volume smallLithium-ion batteries have high energy storage density, 5-7 times that of lead-acid batteries, and are easy to install and carryLow light weightLithium-ion batteries, which weigh about a third as much as lead-acid batteries of the same capacity, can be separated from the car and used at any time● Mileage driven20% to 30% more than lead-acid batteries● Green environmental protectionLithium-ion battery is environmentally friendly, lithium ion battery does not contain lead, mercury, cadmium toxic substances● Super long lifeLithium-ion batteries for electric vehicles usually have an extremely long life of 5-8 years, which is not comparable to lead-acid batteries. With the advantages of performance, lithium-ion batteries gradually expand the market scale, and the increase directly leads to the expansion of output and the decrease of manufacturing costs, which in turn stimulates the market to further increase. Lithium-ion battery products thus embarked on a virtuous cycle of development.● Wide working temperature rangeThe lithium-ion battery for electric bikes can work in the range of -25 degrees to 55 degrees, and its electric capacity can reach 70% of its scale capacity, while lead-acid batteries can only work in the range of 10 degrees to 40 degrees, and can not work properly at -25 degrees.The cooling capability of lithium-ion battery electric vehiclesLithium-ion batteries in charging and discharging process will appear a certain quantity of heat, especially in the process of large current charge and discharge will appear in lithium ion battery inside a lot of heat, but due to the lithium ion battery structure thermal conductivity in different directions exist significant differences, in parallel to the direction of the pole piece is a the significant higher thermal conductivity perpendicular to the direction of the pole piece of the thermal conductivity, Therefore, different cooling methods not only have significant differences in efficiency.The cooling problem of lithium-ion battery electric vehicles has always been one of the key technologies in the industry. Lithium-ion batteries are related to traditional lead-acid batteries, nickel-cadmium batteries and nickel-metal hydride batteries, which have higher energy density and higher charge-discharge rate, so the heat is serious in the working process. Especially in the field of power lithium battery, complex road conditions, harsh environment (especially in high temperature summer), battery heat generation is more intense, the capacity of lithium ion battery, life, especially the safety performance is more significant impact.To some extent, the safety of the lithium ion battery problem is, in fact, its thermal dissipation, lithium ion battery heat production rate is greater than the cooling rate, the battery pack will heat up, once more than the temperature of the battery pack can withstand a tipping point, electrical equipment will be serious safety accidents, so the lithium lithium ion power battery pack heat dissipation problems is very important.Therefore, lithium ion battery manufacturers should carry out thermal management of lithium ion batteries, battery heating and heat dissipation are very important. The former is concerned with cold start, range and power performance, while the latter is concerned with battery system quality assurance life and vehicle safety.

After the implementation of the strong standard, the safety protection technology of power lithium battery becomes the new focus of competition for car manufacturers Recently, a number of car manufacturers have announced their latest ternary lithium ion battery safety protection technology, a time, "no fire", "no explosion" and even "no smoke" ternary lithium ion battery emerge in endlessly.Major breakthroughs have been made in safety protection technology for ternary lithium ion batteriesOn March 10, GAC Aian took the lead in announcing a new generation of power lithium battery safety technology - magazine battery system safety technology (hereinafter referred to as "magazine battery"). Based on "prevent short circuit batteries, after a short circuit, to prevent thermal runaway and prevent heat spreading after thermal runaway" design concept, magazine battery USES the design of similar security module, which can effectively block the spread of the thermal runaway batteries, when batteries are detected voltage or temperature anomalies, such as automatic start battery rapid cooling cooling system to cool the battery.In order to verify the safety of the magazine battery, GAC Aian also published the test video from China Automotive Technology Research Center, which carried out the needling thermal diffusion test on the whole package of the ternary lithium ion battery equipped with the magazine battery system safety technology. The test results show that the whole pack of the magazine battery only briefly fumed 5 minutes after the thermal accident signal was sent out, and there was no fire or explosion.On March 17, Lantu Automobile made a comprehensive interpretation of the three-yuan lithium ion battery pack carried by its first mass-production model Lantu Free in the form of online technology sharing. According to Lantu Automotive, the Lantu Free battery PACK has three important advantages: the first "three-dimensional insulation wall" technology, BMS's original battery safety monitoring and warning model, and the high safety battery PACK method. With the help of these three black technologies, the new battery pack will not smoke, catch fire or explode after being triggered out of control and sending out a thermal event alarm signal.Following the lead of Lantu Automotive, R Automotive announced at the brand conference on March 18 that the R car is capable of achieving L0-class zero-thermal runaway management based on aero-class standards. Through cloud real-time monitoring, efficient and active early warning, we conduct cloud health examination for each power lithium battery, and control the thermal runaway probability of battery pack due to battery core problems within an infinite range close to zero, so as to prevent spontaneous combustion.The results show that the ternary lithium ion battery is prone to thermal runaway fire in some extreme environments due to its poor thermal stability. However, compared with lithium ion iron phosphate battery with relatively high safety performance, ternary lithium ion battery is often used in high-end electric brands because of its high energy density, good low temperature performance, good rate characteristics and other characteristics. Therefore, how to achieve a balance between high performance and high safety of ternary lithium ion batteries has become the focus of industry research and development for many years.And this time, whether it is GAC Aian magazine battery, or Lantu Free "no smoke, no fire, no explosion" battery, or R car L0 level zero thermal control management of non-spontaneous combustion battery, the OEMs in three lithium-ion battery safety protection technology can be said to have made a big breakthrough.Multi-dimensional innovation, ternary lithium ion battery to reach the "three no" levelNew energy battery research and development experts said that ternary lithium ion battery system to achieve "no fire", "no explosion" or even "no smoke", from the material, electrode, cell, system and other dimensions of innovative design and research and development.The current implementation of the more mainstream path has two kinds, one is from batteries ontology, by adding the flame retardant material ontology property improvement, such as, let the batteries in extreme cases, changes in the middle of the body, such as heat absorption, surface passivation and block the expansion and the effect of the mechanical efficiency, etc., in order to realize the batteries not fire; Secondly, materials and designs such as aerogel are added at the module and system levels, so that even if an extreme situation occurs in one cell, the other cells will not be affected.Taking GAC Aian magazine battery as an example, according to the official introduction, the battery pack is from the battery core material, battery structure, cooling system and battery management system four dimensions to improve the safety of power lithium battery.Specifically, in terms of the cell material, the application of nanoscale coating and doping technology of cathode material improves the thermal stability of the cell and prevents thermal runaway; The application of new additives in electrolyte can realize the self-repair of SEI film and improve the life of the cell. High safety electrolyte can spontaneously polymerize at high temperature to form polymer film with high impedance characteristics, which can greatly reduce the heat generation of thermal runaway reaction. The application of these key technologies increases the heat resistance temperature of the cell by 30%.In terms of the battery structure, through the mesh nanopore insulation material and the high temperature resistant upper shell, the super heat insulation safety cabin is formed to realize the thermal runaway of ternary lithium cell and not spread to the adjacent cell. The battery shell can withstand a temperature of more than 1400℃.In terms of cooling system, the magazine battery achieves a 40% increase in heat dissipation area and 30% increase in heat dissipation efficiency through the design of fully fitted liquid cooling system, high-speed heat dissipation channel and highly accurate heat conduction path.The battery management system adopts the latest generation of battery management system chip of the car standard, which can realize all-weather data acquisition 10 times per second, 100 times higher than the previous system, and monitor the battery state with 24-hour full-coverage full-time patrol mode.With the help of the above four core technologies, the whole pack of magazine battery only briefly smoked, without fire or explosion, 5 minutes after the thermal accident signal was sent out during the test. GAC also said that magazine batteries are related to similar ordinary batteries, increasing their energy density by 9.4% by volume and 5.7% by weight, and reducing their cost by 10%. According to the plan, magazine batteries will be introduced in GAC's safety series this year.In contrast, the protection technology of the Lantu Free battery pack can achieve "no smoke" while "no fire, no explosion". And the key to achieve this performance is the three black technology mentioned above: "three-dimensional insulation wall" technology; BMS battery safety monitoring and warning model; High security battery PACK method.According to haze figure automobile new energy technology director Dr Huang, 3 d technology principle of heat insulation wall is inside the battery pack use super insulation flame retardant polymer materials, insulation materials will still be in commonly triggered after thermal runaway battery pack smoke or fire, three-dimensional heat insulation wall technology can do without thermal diffusion phenomenon), for each batteries to achieve individual all-round three-dimensional package. The three-dimensional insulation wall forms a highly efficient insulation and flame retardant protective layer between the electric core and the electric core. Each electric core is fully wrapped in the heat insulation and flame retardant material, shaped like "amber".BMS battery safety monitoring and early warning model is based on BMS cloud guard for big data analysis and tracking, which can realize "thousands of cars, thousands of faces". It is reported that on the basis of the original temperature and voltage warning, the battery pack builds an accurate battery safety monitoring and warning big data model, which tracks the use data of each vehicle and each battery based on different use scenarios (such as plain and mountainous areas, temperature and humidity in the south and north, temperature difference between day and night at high and low elevations, etc.).In addition, Lantu also adopts the high safety battery PACK method, which includes five battery safety structures: customized development of body protection, high strength frame, pressure transfer, deformable energy absorption and battery double safety.In conclusion, the Lantu Free battery pack has made significant improvements in the areas of insulation, monitoring and bodywork, but there is no significant change in the battery material. It is reported that the Lantu Free battery pack electric version will be first shipped with the new battery pack, and shipped in the third quarter of this year.After the implementation of the strong standard, the safety protection technology of power lithium battery becomes the new focus of competition for car manufacturersThe three strong standards for electric vehicles formulated by the Ministry of Industry and Information Technology (MIIT) can be dated back to May 12 last year, when many of the auto manufacturers have announced the latest safety protection technology for ternary lithium ion batteries.On May 12, 2020, The three mandatory national standards (hereinafter referred to as the "three strong standards") formulated by the Ministry of Industry and Information Technology are GB18384-2020 "Safety Requirements for Power Batteries for Electric Vehicles", GB30381-2020 "Safety Requirements for Electric Vehicles" and GB38032-2020 "Safety Requirements for Electric Bus" (hereinafter referred to as the "three strong standards") The Standardization Administration committee approved the announcement, and is scheduled to begin the implementation of January 1, 2021.These three strong standard, the electric car battery safety requirements with dynamic is in the field of power li-ion batteries used in domestic electric cars the first compulsory standards, the standard in the optimization of battery monomer, module, safety requirements and at the same time, focus on strengthening the battery system thermal safety, mechanical safety, electrical safety and functional safety requirements, The test items cover system heat diffusion, external fire, mechanical impact, simulated collision, moisture and heat cycle, vibration water bubble, external short circuit, overheating and overcharging, etc.Among them, it should be particularly pointed out that the standard adds a thermal diffusion test of the battery system, which requires that the battery system shall not fire or explode within 5 minutes after thermal runaway of a single battery, so as to reserve a safe escape time for occupants.According to Wang Zidong, deputy secretary general of China Automobile Power Lithium-ion Battery Industry Innovation Alliance, who participated in the development of the standard, the original intention of the standard is to build a safety bottom line. As for the life safety of consumers, it was originally formulated to take 30 minutes, but later it was adjusted, and 5 minutes is the most basic baseline requirement. No matter what the battery system, from the safety point of view, this standard must be met.In fact, before the formal implementation of the strong standard, in the "no fire" ternary lithium ion battery layout, related power lithium battery companies have already acted.In October 2020, Ningde Times publicly stated that it has developed a "smoke only, no fire" ternary battery. Through high safety electrolyte, thermal expansion isolation technology, direct attack on the pain point of high energy density and high safety, it can ensure that the battery pack does not burn, even if a battery fire, the whole battery pack only smoke.In December of the same year, Honeycomb Energy announced a systematic solution to thermal runaway on its Battery Day -- Cold Bee, which completely solves the thermal runaway problem of the battery system through the original technology at four levels: material, cell, battery pack and monitoring system.Shinwanda also announced in 2020 that it has successfully developed a "smoke-only, fire-free" battery pack, which can pass the "heating trigger cell thermal runaway experiment", that is, after a single cell is triggered and thermal runaway occurs, the whole battery pack will only smoke but not fire.On March 12 this year, as a new power of lithium-ion batteries, ling-pai new energy also announced the "four zero strategies", that is, zero risk, zero attenuation, zero anxiety, zero error. It is reported that Leadpai New Energy carries out innovative design and research and development from multiple dimensions, such as material, electrode, cell and system, so as to prevent thermal runaway and realize zero-risk and high-safety batteries. Its first product of high voltage medium nickel VDA355 cell module will be SOP this year.Based on this, some analysts pointed out that with the formal implementation of strong targets, as well as the power lithium battery company's new technology support, entering 2021, power lithium battery safety protection technology will become a new point for vehicle manufacturers to compete in the field of new energy vehicles after continuing aviation, intelligence, 5G.Summary: For a long time, when we heard of electric vehicle fire, spontaneous combustion and other accidents, the battery is often the first to be listed as the "culprit". Now, under the constraints of national strong standards, under the continuous breakthrough of new technology of power lithium battery companies, and under the strong focus and promotion of vehicle manufacturers, It is believed that "no fire", "no explosion", "no smoke" ternary lithium ion battery will become a reality from one label, and electric vehicle fire, spontaneous combustion accident will no longer exist.

Analysis of Vehicle-mounted Power Lithium Battery System and Charging Technology of Charger? 1 On-board lithium ion battery management systemAs the monitoring brain of electric vehicle battery, the battery management system (BMS) in hybrid electric vehicle can realize the monitoring of the remaining battery power, predict the power intensity of the battery, and facilitate the understanding of the whole battery system and the control of the vehicle system.In pure electric vehicles, BMS has intelligent adjustment functions such as predicting battery remaining power, predicting driving range and fault diagnosis. The use of BMS is particularly obvious for lithium-ion batteries, which can improve the service state of the battery, extend the life of the battery, and increase the safety of the battery. BMS will be a key technology for the future development of electric vehicles.Research on Vehicle Lithium Ion Power Lithium Battery System and Charging Technology of ChargerAs shown in Figure 1, the data acquisition module in the BMS measures the voltage, current and temperature of the battery pack, and then transmits the collected data to the thermal management module and the safety management module respectively for data display. The thermal management module controls the temperature of the battery cell to ensure that the battery pack is in the optimal temperature range.The safety management module judges the battery pack's voltage, current, temperature and SOC estimation results, and sends out fault alarm and takes emergency protection measures such as circuit break in time when a fault occurs. The state estimation module calculates SOC and health status (SOH) according to the collected battery status data.At present, SOC estimation is important, and SOH estimation technology is not mature yet. The energy management module controls the charge and discharge process of the battery, including the balance management of battery power, which is used to eliminate the problem of inconsistent power of the battery pack. The data communication module adopts CAN communication mode to realize the communication between BMS and on-board equipment and non-on-board equipment.The core functions of BMS are SOC estimation, equalization management and thermal management. In addition, BMS also has other functions such as charge and discharge management, charge management of pre-charger and so on. In the process of battery charging and discharging, management should be carried out according to the relevant parameters such as environmental state and battery state, and the optimal charging and discharging curve of the battery should be set, such as the charging current of the charger, the charging upper limit voltage of the charger and the discharging lower limit voltage of the charger. The capacitive load existing in the high-voltage system circuit of electric vehicles is equivalent to short circuit at the moment of power-on, so it is necessary to carry out the charging management of pre-charging machine to prevent the transient current impact on the high-voltage circuit.2 Core functions of battery management system2.1 SOC estimationSOC is used to describe the remaining charge of the battery, which is one of the most important parameters in the battery life. SOC estimation is the basis to judge the battery overcharge and overdischarge. Accurate estimation can prevent the battery pack from overcharge and discharge to the maximum extent and make it run more reliably.The estimation of battery SOC is highly nonlinear under the influence of the internal working environment and the external use environment. There are many internal and external factors that affect the battery capacity, such as battery temperature, battery life, battery internal resistance, etc. It is very difficult to accurately complete the SOC estimation.Existing SOC estimation methods are as follows:(1) ampere-hour measurement method. The ampere-hour measurement method does not consider the changes in the internal structure and state of the battery, so it has the advantages of simple structure and convenient operation, but the accuracy of this method is not high. If the current measurement accuracy is not high, then with the passage of time, the cumulative error of SOC will continue to increase, affecting the final results. This method is suitable for measuring the battery SOC in electric vehicles. If the measurement accuracy can be improved, it can be regarded as a simple and reliable method for measuring the SOC.(2) open-circuit voltage method. The open circuit voltage of lithium-ion battery has an approximate linear relationship with SOC, which can be used to judge the internal state of the battery. However, due to the strict measurement requirements, the battery standing time should be at least 1h, which is not suitable for the online real-time detection of the battery in electric vehicles alone. In general, the open-circuit voltage method is often combined with the ampere-hour measurement method because of its high accuracy in the estimation of the value at the beginning and end of charging.(3) Kalman filtering method. Due to its excellent error correction ability, Kalman filter method is especially suitable for hybrid lithium battery with severe current fluctuation. The disadvantage of this estimation method is that it requires high system processing speed.(4) Neural network method. Neural network has the characteristics of distributed parallel processing, nonlinear mapping and adaptive learning, so it can be used to simulate the dynamic characteristics of batteries and estimate the SOC. However, this method requires a large number of reference data for the neural network to learn, and the data and training methods are required to be high, otherwise it will cause unacceptable errors.2.2 Balanced managementIn the process of making a battery, there are many processes, and differentiation will lead to inconsistency. The difference of the battery is important in the change of time and temperature, its internal resistance and capacity will be different. Large differences between monomers are more likely to cause overcharge or overdischarge, resulting in battery damage. Realizing battery balance can maximize the utility of power lithium battery, prolong the battery life, and increase the safety. At present, the mainstream equilibrium methods at home and abroad are as follows:(1) resistance equalization method. This method is an important representative of energy dissipation equalization method. The method is simple and low-cost, but the energy loss is relatively large and the efficiency is low. It is only applicable to the system with low current charge and discharge.(2) Switching capacitance method. This method is an important representative of non-dissipative equalization method, and it makes up for the shortcoming of resistance equalization. But its control circuit is complex, the balance speed is slow, the time is long, is not suitable for large current use.(3) transformer equalization method. This method is an active equalization control method of series battery pack based on symmetric multi-winding transformer structure. Its disadvantage is that the circuit is complex, the device is many, the volume is too large, is not easy to expand the battery pack. It is generally used in charge and discharge of large current.(4) Centralized equilibrium. The method can quickly transfer energy from the entire battery pack to the individual cells, and the volume of the centralized equalization module is smaller. However, the balancing operation of multiple batteries cannot be carried out in parallel and requires a large number of cable connections, which is not suitable for the battery pack with a large number of batteries.2.3 Heat managementTemperature affects all aspects of battery performance. The inhomogeneity of temperature field will aggravate the inconsistency of battery pack, so it is necessary to manage it. The purpose of thermal management is to maintain the temperature of the battery system within a certain range through heating or cooling measures, and to maintain as much temperature consistency as possible within the battery pack.Temperature management is important to complete the following four functions :(1) rapid heating of the battery pack under the condition of low resistance; (2) To ensure the uniform distribution of battery temperature field; (3) Accurate measurement and monitoring of battery temperature; (4) Effectively evacuate heat when the battery pack temperature is too high. Commonly used cooling methods include natural convection method, forced air convection method, liquid flow method, phase change material method and thermal management method, etc., commonly used heating methods include battery internal heating method, heating plate method, heating sleeve method and heat pump method.Charging technology of lithium-ion battery charger3.1 Current situation and development trendIn practical application, it is necessary to choose different charging modes according to the limitation of battery capacity to prolong the service life of the battery. There are many charging methods for lithium-ion battery chargers, among which the simplest is the constant voltage chargers. Lithium-ion battery pack is generally composed of a large number of monomers in series. Due to the difference in the manufacturing process of each monomer, there is inconsistency in internal resistance, voltage, capacity and temperature, which is easy to cause the imbalance in the process of charge and discharge, that is, the large capacity monomer is shallow, the small capacity monomer is overput, which will cause serious damage to the battery pack. The problem of unbalanced charge and discharge is the focus of research on lithium ion battery pack.The charging technology requirements of battery chargers for electric vehicles include:(1) The charging process of the charger is fast. Low specific energy of power lithium-ion batteries leads to short charging range of single-use rechargers, which has been an important factor limiting the development of electric vehicles. As long as the battery can be charged faster and more efficiently by the charger, the short range of electric vehicles can be indirectly remedied.(2) Generalization of charger charging equipment. In order to pursue the relevant academic frontier, optimize their own products for as much as possible market share, a variety of new batteries emerge in an endless stream, and coexist in this market. In the case of different types and different voltage levels of batteries coexist, the charging equipment of the charger in public places should have a wider adaptability. On the one hand, the charger should be applicable to as many batteries as possible; on the other hand, the charger charger should meet the requirements of customers for different voltage levels.(3) Intelligent charging strategy of the charger. In order to realize the non-destructive charging of the battery, monitor its charge and discharge status, prevent over discharge, and achieve the purpose of saving energy and delaying aging, a more intelligent charging strategy of the charger is needed. That is, different charging strategies are supplied for different batteries to match the charging curve of the battery charger.(4) High efficiency of electric energy transformation. The energy consumption of electric vehicles is closely related to the operating cost. In order to further promote electric vehicles, it is necessary to balance their cost performance and reduce energy consumption as much as possible.(5) Integration of the charging system of the charger. With system miniaturization and more functional requirements, as well as the improvement of reliability and stability, battery charger charging system and electric energy management system as a whole, integrated electric current detection and reverse discharge protection function, to achieve a smaller need for external components, integration of higher charger charging solution, Thus, the arrangement space is saved for the other parts of the electric vehicle, the system cost is greatly reduced, and the charging effect of the charger can be optimized and the battery life can be extended.3.2 Charging technology of intelligent chargerBased on the above analysis of the charging status of lithium-ion battery pack and its charger, this paper summarizes a charging mode of intelligent charger based on electric vehicle BMS, as shown in Figure 2, aiming at the problems of unbalance and safety that are likely to occur in the charging process of lithium-ion battery pack.Research on Vehicle Lithium Ion Power Lithium Battery System and Charging Technology of ChargerIn the whole charging process of the charger, the BMS system is important for the monitoring of battery voltage and current signals, temperature and connection status of the lithium ion battery pack. The intelligent management system in the charger can monitor the output mode of the charging device in real time. Intelligent communication is realized between the BMS system and the intelligent management system of the charging equipment of the battery pack. Real-time mode comparison of the state of the battery pack and the charging equipment of the battery pack is carried out, and the optimal charging mode of the battery pack is selected.In the initial charging process of the battery, BMS estimates the maximum allowable charging amount of the lithium-ion battery pack, that is, carries out SOC assessment on the monomer of the entire battery pack to measure the maximum chargeable amount of the battery pack. Combined with the pre-set safety factor of the charging amount of the charger, the maximum allowable charging amount of the battery pack is calculated.During the charging process, the lithium ion battery pack is charged according to the maximum allowable charging amount of the charger. Make full use of the energy management module of BMS to control the charging balance of the battery pack to ensure the consistency of the parameters of the battery pack. At the same time, in the charging process of the charger, the SOC value should be detected periodically (the detection period is determined according to the new gradient of the battery charge).Using the state estimation function of the BMS system, combined with safety management, the battery pack can be maximally prevented from overcharging. After reaching the maximum charging capacity of the battery pack, both the BMS and the intelligent management system of the charging device of the battery pack can intelligently control the charging controller of the battery pack and end the charging process of the battery pack. At the same time, the BMS disconnects the communication with the charging device monitoring system.The charging mode of the intelligent charger can not only solve the problem of unbalanced charging of the lithium-ion battery pack charger, but also ensure the charging safety of the battery pack charger to the maximum extent, prolong the service life of the lithium-ion battery pack and ensure its use safety.4 Lithium ion battery detection technologyChina has vigorously developed the electric vehicle industry and actively promoted the construction of charging facilities for related chargers. However, many problems have been found in the operation of these demonstration devices, such as the screening and matching of batteries, the heating of the equipment, and the poor contact of the plug and unplug interface of the connecting device. If these problems can not be solved in a small number of devices, after a large number of applications of electric vehicles, there will be a situation of inundation, which is bound to have a negative impact on its development.With the massive construction of electric vehicle infrastructure, there is an urgent need for related testing methods. Tianjin Electric Power Company carried out the project "Research on Testing Technology of Key Charging Equipment of Mobile Electric Vehicle Chargers", in which the most important test for the electrical changing station of electric vehicles was the test of battery pack.Battery fault diagnosis, screening maintenance and charging technology based on BMS monitoring are important in electric vehicle electrical changing stations. The performance of battery screening devices and rechargers will be mainly tested. The research and mastery of the characteristics of lithium-ion batteries is conducive to the judgment of the accuracy of screening devices in electrical changing stations and the improvement of battery life.Through the investigation of a large number of key charging equipment of chargers that have been put into operation, it is helpful to master their operating characteristics and fault characteristics, improve detection efficiency, and form a simple and quick mobile detection method. This will be a strong core technology support, conducive to the overall development of electric vehicles.

All the commodities in the world are produced because of people's needs. According to the needs, especially with the development of human science and technology, more and more new products come out. This is the portable solar power generator or portable solar power system, and there is an interesting story about the origin of the best portable solar generator.                                  An obstetrician from the United States is said to be on a medical assistance mission in Africa. During a cesarean section at night, she witnessed the pain of having to operate only with oil lamps. The refinery lights went out during the operation, but the whole operation was carried out by flashlight.Shocked by the severe lack of electricity in this remote area, she pondered a solution. Her husband worked for a solar energy company, so he did a series of experiments using different combinations of solar panels and lights to create a portable solar power generator that could be used in medical care.Simply put, it is a combination of solar panels, batteries, and some accessories. A watt-sized solar panel, a 12-ampere sealed lead-acid battery, a controller, a solar inverter, and some Led lights make up a small solar lighting system. Many remote villages lack electricity, but there is plenty of daylight. So the portable solar power generator could be charged by sunlight during the day and powered at night.Today, such portable solar power generators are used in nearly 200 medical clinics in different regions. It can also be used in a variety of emergency medical care. Thanks to the invention, many mothers in remote areas can no longer rely on kerosene lamps alone for 24-hour emergency medical care.Portable solar power generators for household powersolar generator kits produce only a very limited amount of electricity per day compared to installing solar systems in homes, but they are very practical for the average rural household. It can be thought of as a portable household power source. First of all, this kind of solar generator is simple in structure, no extra wiring is needed, and all the components work in coordination, which saves the trouble of installation and testing. It is very simple to operate. Secondly, it can be very small, people can choose the right generator according to their own lowest electricity consumption, which means that you can save as much money as possible. Nowadays, many countries are facing a serious energy crisis, especially in remote areas, many homes are still without access to the electric grid, or there are frequent power cuts and interconnections. To make matters worse, the world's fossil fuels such as coal and oil are being consumed at an accelerating rate. We should all be developing renewable energy, and this solar generator is an ideal source of power.In poor areas, governments or Non-Governmental organizations give solar generators to poor households as lighting appliances, and then more households with no electricity need such equipment. With the development of solar energy technology, products will become more and more practical, whether it is used in off-grid homes, or as a backup power source in the event of power failure, which is a good choice. There is some certainty that solar generators will become common household energy devices.Portable solar power generators can be widely used in remote areas, outdoor fishing, outdoor camping, islands, frontier posts, fishing boats, grasslands, and other areas and places without electricity. The multi-purpose solar power system can not only meet lighting needs but also charge electronic devices such as mobile phones, digital cameras, and digital players. So what are the pros and cons of a small portable solar system?Advantages of portable solar power generation system1, the universality of solar energy, there is no geographical limit, can be nearby power supply, solar energy is inexhaustible, the surface of the earth received solar radiation energy, can meet the global energy needs of 10,000 times. 2. Low cost of solar energy, no moving parts, easy to use and damage, simple maintenance, especially suitable for unattended use.3, the environmental protection of solar power generation, solar power generation will not produce waste, no pollution, noise, and other public hazards, no adverse impact on the environment, is the ideal clean energy.4. Stable voltage, high power quality, widely used in all kinds of electrical equipment, very suitable for rural, farm, mountain, island, highway, and other remote places of electricity, is also an excellent emergency standby power supply.