In people's daily life, ternary lithium-ion battery electric vehicles are often used. Electric vehicles can be said to be the most important type of transportation vehicles in modern times. For electric vehicles, the most important core component is electric vehicle batteries. Everyone will often see the description of the battery capacity on the battery of the electric car. How to measure the battery capacity of the electric car? Let me introduce you to the following:
Rated capacity is the minimum amount of electricity that is specified or guaranteed to be discharged under certain discharge conditions when designing and manufacturing a battery, often referred to as the nominal capacity. It is worth noting that a battery capacity is determined by the capacity of one of the electrodes, not the sum of the positive and negative capacities. Therefore, the actual battery capacity is determined by the smaller capacity of the electrode, and in general, the actual capacity of the negative electrode is excessive, and the positive electrode capacity defines the capacity of the entire battery. This is what everyone needs to know before they know how to measure the battery capacity of an electric car.
The method for measuring the capacity of the ternary lithium ion battery is basically the same as the method for detecting the discharge performance of the battery, and there are a constant current discharge method, a constant resistance discharge method, a constant voltage discharge method, a constant voltage constant current discharge method, a continuous discharge method, and an intermittent discharge method. The capacity of the battery can be calculated based on the time of discharge and the magnitude of the current. The following mainly introduces the constant current discharge method:
The discharge capacity of the galvanostatic method has a great relationship with the discharge current, and the discharge temperature, the charging system, the hold time, and the like all have an effect on the capacity. Under the same discharge system, the charging efficiency of the battery is inconsistent for different charging systems, so the discharge capacity of the battery will be different. Similarly, under the same charging system, the test of the discharge capacity is carried out after being left for 10 minutes and left for 1 hour, and the result will be 2% to 5%, depending on the self-discharge performance of the battery.
The discharge current is not constant during the discharge of the constant resistance method test capacity. The lithium iron phosphate lithium ion battery has a large discharge current and then gradually becomes smaller. The larger the discharge resistance is, the smaller the discharge current is, the smaller the voltage drop is generated, the lower the operating voltage is, the discharge curve is flatter, and the discharge capacity is larger.
Through the above introduction, I believe that everyone has a clear understanding of how to measure the battery capacity of electric vehicles!
The national standard for electric vehicle battery capacity is the two-hour discharge rate, which means that no matter how big your battery is, the battery is discharged for two hours. For example, the battery is discharged at a current of 5A per hour for two hours. The capacity of the battery is 10AH per hour. The current of 10A is discharged for two hours. The capacity of this battery is 20AH. Now some non-standard batteries are marked like this, that is to say it is not a national standard discharge, it is discharged for 5 hours at a current of 2.4A per hour. The current of 2.4A is simply useless for electric vehicles. So pay attention to this sign (5hr) when buying a battery. If there is no such sign, it is the national standard, there is this sign, huh, no need to say it!
The capacity is written on the battery. If you take a battery, you can't see it. It looks like this. 6-DZM-14. It means that the battery is 14AH, 6-DZM-12 is 12AH, 6-DZM- 10 is 10AH. 6-DZM is a lead-acid type battery, the latter number is representative of the capacity. There are also 17AH.20AH
Below. I will introduce you to the scientific use of electric vehicles.
First, how to use the battery to extend the battery life?
Experienced users know that the cost of batteries is the biggest consumption of electric bicycles, so users are very concerned about the problem of extending the service life of lithium iron phosphate lithium-ion batteries. The first thing to assume is that there is no problem with the charger, and whether the user is using it correctly is critical to the life of the battery. The precautions for using the battery are as follows
Protect the charger. The general instructions for use protect the charger. Many users do not have the habit of reading the manual. They often think of looking for the manual after the problem. It is often too late, so it is very necessary to read the manual first. In order to reduce the cost, the current chargers basically do not have a high vibration-resistant design, so that the charger is generally not placed in the trunk and basket of the electric bicycle. In special cases, it is necessary to move, and the charger should be wrapped with soft materials such as raincoats to prevent the bumps of vibration. After many chargers are vibrated, their internal potentiometers will drift, causing the entire parameters to drift, resulting in an abnormal state of charge. Another thing to note is that the charger should be kept ventilated during charging. Otherwise, it will not only affect the life of the charger, but also cause thermal drift and affect the state of charge. This will cause damage to the battery. Therefore, it is very important to protect the charger.
Charge every day, even if your ability to continue is not long, you can use it for 2 to 3 days, but it is recommended that you charge every day, so that the battery is in a shallow cycle, the battery life will be extended. Some early-use mobile phone users think that the battery is best recharged after basic use, this view is wrong, the memory efficiency of lead-acid batteries is not so strong. Frequent discharge of electricity has a greater impact on the life of the battery. Most chargers may charge 97% to 99% of the battery after the indicator light is fully charged. Although only undercharge of 1% to 3% of the power, the impact on the continuation ability can be neglected, but it will also form undercharge accumulation, so after the battery is fully charged, it will continue to float as much as possible, to suppress battery vulcanization. beneficial.
Charge in time. The lithium manganate lithium ion battery began the vulcanization process after discharge, and at 12 hours, significant vulcanization occurred. Timely charging can remove non-severe vulcanization. If not recharged in time, these vulcanized crystals will accumulate and gradually form coarse crystals. The general charger is powerless to these coarse crystals, which will gradually reduce the battery capacity and shorten the capacity. Battery life. Therefore, in addition to daily charging, it is also necessary to pay attention to the early charging after use, as much as possible to make the battery full.
Make full use of lithium manganese oxide lithium ion battery maintenance conditions Many electric bicycle dealers can provide battery maintenance and repair services, you should make full use of these services. Some brands of electric bicycles have been proposed to overhaul the battery. For example, regular maintenance of the battery can reduce damage to the battery. The repair of the state of charge of the battery can alleviate the "battery behind" failure, which is a breeze for dealers equipped with maintenance capabilities. For water loss, when the battery capacity is 70%, the hydration effect is better than the battery capacity of 40%. Even some brands of products have suggested that failure to overhaul at the specified time is equivalent to abandoning the warranty period of the battery. Consumers are subject to losses that should not occur. Therefore, consumers should make full use of the conditions of battery maintenance to increase the service life of the battery.
Through these methods, users can greatly extend the battery life. Some users have relatively short mileage, battery life is relatively long, and some problems are relatively difficult to find. Therefore, the "deep discharge" measure mentioned in Article 4 is also an effective way to find the battery problem in time, and it is difficult to deal with when the battery problem is serious.
Proper maintenance can make the battery last longer and save more investment. Be careful to first install the battery firmly to prevent damage to the battery during riding. Otherwise, when the car is driving on bumpy road conditions, the battery may be shaken or even detached and damaged. Secondly, always check the battery connection line, the live joint is secure, and the contact between the line and the joint is good. Otherwise, it may cause an electric spark, which may cause the battery to explode.
Second, electric vehicle maintenance precautions
1, diligent charging --- lead-acid batteries should be kept with the habit of charging, can not wait until the battery is recharged, this will affect battery life. If it is not used for a long time, charge it once a month. Please use the matching dedicated charger for charging.
2, more maintenance --- in case of rain, can not let the water drown the hub center; when the vehicle is off, close the door in time, usually the tires are full of gas; in the case of heavy loads such as uphill and top wind, use the pedal boost In the event of a fault, promptly send it to the special maintenance department designated by the manufacturer for repair.
3, diligent lubrication---According to the use situation, the front axle, rear axle, middle axle, flywheel, fork, shock absorber pivot point and other components should be scrubbed and lubricated every six months to one year (recommended to use molybdenum disulfide lubrication fat). The transmission components in the electric hub have been coated with special lubricants, so users do not have to scrub the lubrication themselves.