Lithium batteries are divided into lithium metal batteries, lithium ion batteries and lithium polymer batteries; Lithium metal batteries are generally used as primary batteries, that is, non-rechargeable batteries. Their discharge current is not large and their applications. are not very widely; The lithium battery we often talk about at present is actually a lithium ion battery, which is also the most widely used lithium battery at present. Lithium polymer battery is the third generation lithium battery. The density, maximum discharge current, environmental pollution and other parameters are the best among the current three lithium batteries, and the future development trend is expected to be the best. Additionally, its charge management and protection parts are almost compatible with existing lithium-ion batteries and are. tvery practical to use. In the following text, the lithium-ion battery is used as an example to illustrate the design of the protection circuit. In the text, lithium battery refers to lithium-ion battery. The nominal voltage of conventional lithium batteries is 3.6 V or 3.7 V, and it is 4.1 V or 4.2 V when fully charged. I will then present the design principle of a single-cell lithium battery protection circuit. Protection circuit function: Overcharge protection: For lithium batteries, the maximum voltage after charging should not exceed 4.2V, otherwise the battery electrolyte will be decomposed, causing the temperature to rise and producing gas, thereby reducing battery life. , seriously Sometimes it may even cause an explosion, so the lithium battery protection circuit must ensure that the lithium battery does notis never overloaded. Some characteristics of lithium ion battery protection board and what to pay attention to: A: Features: (1) Main technical parameters: a. Overload protection voltage? Discharge protection voltage. E. Recovery voltage in case of excessive discharge F. Self-consumption in normal operation G. Self-consumption current in standby state (static operating current) h. factory defined parameters. , I've never been exposed to programmable lithium protection, there should be one, but usually they work on the power management chip, and no one wants to do that on the protection board.
Why can't a single cell lithium battery protection plate be used in series with multiple cells?
The application of lithium batteries iron on the energy storage market to become popopular. The business opportunity of secondary application of lithium batteries in energy storage systems has taken shape, making lithium iron batteries with high conversion efficiency and cycle life a popular choice and a popular choice for replace lead-acid batteries. for electric vehicles, but also It shines in solar energy, small energy storage devices and other equipment.
Business opportunities for the secondary application of lithium batteries in electric vehicles in energy storage systems (ESS) are poised to explode. Driven by relevant industry players, there are already basic business models for recycling electric vehicle lithium batteries into energy storage systems, including the substitution effect model caused by remanufacturing of lithium batteries, battery rentales of electric vehicles and energy service models of systems, etc., which should be promoted. Helping electric vehicle lithium battery energy storage business opportunities take shape.
It is worth noting that, driven by the lithium battery energy storage market, lithium iron batteries enjoy their advantages such as high energy density, high voltage and low self-discharge rate in lithium cobalt (LiCoO2). ), lithium-manganese (LiMn2O4) and ternary (LiCoNi1-XO2) batteries stand out and are expected to gradually replace lead-acid batteries and become the main battery for energy storage applications.
The business model is gradually taking shape, and the outlook for lithium battery energy storage is promising
Li Yongjian, research director of the Industrial Consulting Center of the Institute of industrial researchiel of Tuoyuan, said: The lithium secondary battery energy storage market for electric vehicles is taking shape and will add more advantages to the electric vehicle market.
Li Yongjian, research director of the Industrial Consulting Center of Tuoyuan Industrial Research Institute, said that when the lithium battery capacity (state of charge, SOC) remains at 80% , it can no longer supply electricity. Vehicles However, the lithium battery for electric vehicles When 40-80% of the battery capacity remains, it still has a high energy storage value. It can be used by ordinary households after each charge and has about 2 days of power consumption. thus becoming a new business opportunity in the energy storage market.
Li Yongjian believes that global market demand for lithium secondary battery energy storage systemsm for electric vehicles will increase significantly, from 204 milliwatts/hour (mW/h) last year to 1,520 mW/h in 2013. the value of global energy storage systems will increase from approximately 8.5 billion NT dollars to approximately NT$52.4 billion, and market opportunities are expected to expand.
It is understood that one of the business models for the redesign of lithium battery energy storage systems is the substitution effect model. Looking at the business model of Japanese company 4R Energy, high-power lithium batteries are recycled and rebuilt. use in Compared with the price of a new lithium battery energy storage system, the price of the energy storage system is significantly different, resulting in a substitution effect.
On the other hand, energy storage systems can provide electricity to individual homes, buildingss and communities through standalone microgrids used by communities and businesses, also because they use renewable energy to produce electricity, they can alleviate the problem; need for new electricity transmission and distribution systems Investment pressure on lines and new power plants can thus reduce the investment cost of the electricity network. In addition, the secondary lithium battery energy storage system can also schedule power generation in advance for the distributed power generation system of the microgrid, so that the lithium secondary battery energy storage system can energy can provide power at a specific time, especially for electrical support during power peaks; consumption periods, it can improve the overall benefits of the energy management mechanism can further reduce the cost of power supply penduring peak periods.
It is worth noting that 4R Energy, a company owned 51% and 49% by Nissan and Sumitomo Group respectively, is engaged in the reuse of used batteries for electric vehicles and the promotion of related activities . to inject vitality into the lithium secondary battery energy storage market.
In fact, the San Diego National Laboratory (SNL) in the United States established the concept of lithium secondary battery applications for electric vehicles in 2002, but the standards, specifications and methods of relevant implementation are still the subject of academic research. . scene. Li Yongjian admitted that the high cost of lithium batteries for electric vehicles has led to low consumer acceptance of electric vehicles, resulting in electric vehicles still not being popular enough.
However, the current dilemma of the maThe market for electric vehicles can be solved using the electric vehicle lithium battery leasing model. Li Yongjian analyzed that through leasing electric vehicle lithium batteries, consumers can reduce the cost of purchasing an electric vehicle in one go and increase their purchase intention. When the number of electric vehicles increases, this may also increase sources of secondary lithium recycling. batteries for electric vehicles, which canWe hope to generate two industrial booms at once.
Replacement of lead-acid batteries with lithium-iron batteries with high conversion efficiency
On the other hand, the development of energy storage applications of lithium batteries has also increased the role of lithium-iron batteries. Lithium iron batteries have advantages such as high conversion efficiency and long service life. They were adopteded by manufacturers such as Sharp and Youliang in a variety of home/commercial energy storage devices and are expected to expand the scope of application of lithium iron. batteries.
Ke Weixin, deputy director of Shangzhi precision lithium battery business division, pointed out that lithium iron batteries have high conversion efficiency, high energy density, high voltage and low self-discharge rate, and should gradually replace lead-acid batteries.
Ke Weixin, deputy director of Shangzhi precision lithium battery business division, said that the energy efficiency of lithium iron batteries is 95% and the service life is more than 2,000 times, which is compared to 60% efficiency. and 400 times of use of lead acid batteries. Surpassing many and having the advantages of high energy density, high voltage and low autode ratecharge, it will gradually replace lead batteries.
It is understood that the lithium iron batteries and powder materials currently used in Sharp and Youliang energy storage systems are manufactured in Taiwan. Some of them originally used lithium manganese batteries, but since lithium iron batteries have a long service life, can be used under rapid charge and discharge conditions, and are suitable for use In high-power discharge energy storage systems, the company has gradually shifted to lithium-iron batteries. Development of energy storage systems.
Ke Weixin pointed out that lithium iron batteries made from refined lithium iron powder have shorter charging time and lighter weight than lead-acid batteries and nickel batteries. -metal hydride, and can increase their capacity and power. partyully suitable for starting electric vehicle batteries, the application range covers electric scooters, plug-in hybrid electric vehicles, electric cleaning vehicles, electric motorcycles and electric boats, which can extend the use time and have better climbing ability.
In addition, lithium iron batteries can also be used in renewable energy storage systems, such as wind and solar power generation systems. The stronger the wind intensity, the greater and stronger the current generated. The intensity of the sun, the higher the charging current, which can provide large current charging and discharging capabilities.
In addition, lithium iron batteries can also be used in small energy storage devices, such as emergency first aid kits, mobile power suppliesfor camping and mobile power supplies for stands, etc., which can provide four to six hours of DC power.
Each battery in the 18650 lithium battery pack needs to have its own protection plate, or does a battery group only need one protection plate?
First: If multiple protection plates are used, the overall internal resistance of the battery will be high, 60 mΩ inside a single cell board. Each time you use an additional single cell card, the internal resistance will increase by that amount and the actual power released will decrease.
Second: The consistency of the battery cells is already different. After adding the protection board, the consistency between the voltages of each cell is even worse.
Third: If desired. balance, you cannot add a single board to each cell, you can only do it sur several string boards.
Fourth: Adding only one plate to each cell increases potential risks such as short circuits and reduces reliability.
How many battery protection plates at lithium are necessary? How to calculate
The 18650 lithium battery has only one guarantorProtection plate, which protects the entire lithium battery from overcharge, overdischarge and overcurrent; The function of the protection plate is mainly to protect the cells of the rechargeable battery, maintain safety and stability during charging and discharging of the battery, and protect the entire battery. circuit system. Performance plays an important role.
Protection panels are classified by battery
1) Single section protection panel
2) Double section protection panel
3) Multi-section protection panel
At hCurrently, the most common lithium batteries on the market are two types of batteries, lithium iron phosphate batteries and ternary batteries. The hardware systems of lithium iron phosphate batteries and ternary batteries are different. Lithium iron phosphate is 3.2V voltage platform and has a lifespan of more than 2000 times. Ternary batteries are a voltage platform of 3.7 V. The service life depends on different manufacturers. and different models. And the technology, some can reach 500 cycles, and some can reach more than 1,000 cycles. Lithium iron batteries have good high temperature performance, and ternary batteries have good low temperature performance.
In terms of safety, lithium iron is better. Choose ternary batteries and assemble them into a 48V battery. Using ternary batteries requires 13 strings. Rated voltagewill be higher and the number of strings assembled in the battery will be smaller. Choose lithium iron phosphate batteries to assemble into a 48V battery. Using lithium iron phosphate batteries requires 16 strings. The rated voltage value is only 3.2V. More batteries are needed in series to increase the voltage.
Many people think that if my battery is 48V20AH, I should use 20A protection board, if my battery is 48V80AH, I will use 80A protection board, etc. I choose the protection card based on the capacity. This concept is completely false. It is recommended to confirm the specific parameters of the protection board in terms of product power, voltage requirements, various functions, etc.
Detailed information
When lithium batteries are used, they will be combined in series and parallel according to the toperating ension of the load and the required capacity. Lithium batteries are assembled into lithium battery packs, such as 48V, 60V, etc., common in electric vehicles.
So when choosing a protection board, you must first determine the single battery type and whether the voltage is 3.2V or 3.7V or other voltages , then determine the voltage of the entire group or battery. The group consists of several chains of cells. The management chips of some protection boards have reserved battery voltage selection terminals, and the rated voltage of the single battery can be adjusted through the high and low levels of the port.