My love for electric cars is obvious. I have been driving all-electric cars for more than four years, with a mileage of 60,000 miles and about 100,000 kilometers. There are many reasons why I choose electric cars, but in the end it is because electric cars are really great. It's quiet and surprising; its acceleration performance is unmatched; there is no need to change the oil; and wherever you want to go, there is no need to consider the impact of speed or time on mileage. From 4 series (micro hybrid cars) to 12-16 series batteries (light hybrid cars), up to 96 series batteries (electric and hybrid cars), depending on the car's specifications, there will be a section or Many sections are connected in parallel. However, from the perspective of the IC, the number of series battery sections is the key point, and the number of parallel battery sections can be arbitrarily determined as needed. The Battery Management System (BMS) is an important link between the driver, the car and the battery. The BMS contains electronic components that monitor and protect the battery. I am always curious about the performance of these battery management electronic components, especially the performance of the power management IC such as the bq76PL455A-Q1; in fact, it is this device that enables my car to drive normally and improve the vehicle. Performance. As a driver, I urgently need to know the battery's cruising range and the time the car is fully charged. I also want to know if my battery status is not good. I will be happy if I can still know that my car is accelerating very fast. Let's take a look at how the different technical specifications of the IC help to achieve the functionality I need. Cruising range and acceleration The cruising range is another way to understand the residual charge of the battery. This parameter is called the state of charge (SoC). Anyone with a mobile phone knows that the capacity of the battery will gradually decrease over time. The maximum amount of charge a battery can hold at a given point in time is called the state of health (SoH). There are many ways to calculate SoH and SoC (see TI Impedance TrackTM technology), but these methods all calculate battery voltage, battery temperature, and battery current. Some lithium-ion chemical batteries, such as lithium iron phosphate batteries, have a very flat curve of SoC relative to battery voltage. A small error in the battery voltage can lead to large errors in the SoC estimation. SoC curve of a LiFEPO4 battery Monitoring requires measuring voltage, current, and temperature. A monitoring IC such as the bq76PL455A-Q1 has an accuracy of 2mV over a temperature range of 0°C to 65°C for a battery voltage of approximately 4.5V and an accuracy range of -40°C to 105°C. For 4mV, battery voltage accuracy is usually largely dependent on the input voltage. Please note that what I am discussing here is true accuracy: this accuracy includes all offsets caused by reflow soldering and the first few thermal cycles. Sometimes, the datasheet specifications will be very different from what you see on the board. Acceleration is also closely related to SoC, and as the battery voltage drops, the maximum power that the battery can produce also drops. Excessive current on any SoC, especially at low SoCs, can age very quickly. safety So far, the battery has been used in cars for 150 years, so car manufacturers are also helping you in this regard. How did they do it? The time it takes for the car to stop charging and discharging is just right. Typically, a BMS has a separate protector - this is a set of comparators that check the voltage of each cell and ensure that the battery voltage is within the correct range. If the monitor or protector detects that a battery is at an overpressure threshold or is undervoltage, charging or discharging will terminate. If the monitor or protector underreports the voltage, the other will stop charging and discharging. In fact, although failures rarely occur, most automakers spend most of their time developing car safety. This is why an IC has so many self-diagnostic features, and a monitor can diagnose the cause of most systems. For example, the bq76PL455A-Q1 is capable of checking for line breaks, has a built-in self test to verify defined internal functions, and is able to assist users in a variety of ways. cost Like my love for electric cars, I also hope that electric cars can be cheaper. Obviously, batteries account for a large share of the cost of automobiles. The easiest way to reduce costs is to do more with less. In the field of battery applications, this means a smaller guard band, which in turn means more accurate monitors and protectors. Normally, the protector is not as accurate as the monitor, so the actual number of guard bands is increased by the accuracy of the protector. SMA means surface mount assembly. It is a new generation of electronic assembly technology, which compresses traditional electronic components into a device with a volume of only a few tenths. Surface Mount SMA,Surface Mount Standard Rectifiers,Smd Bridge Rectifier Changzhou Changyuan Electronic Co., Ltd. , https://www.cydiode.com
Surface mounting is not a new concept, it is derived from earlier processes, such as flat mounting and mixed mounting.
For the assembly of electronic circuits, a point-to-point wiring method was initially adopted, and there was no substrate at all. The packaging of the first semiconductor device uses radial pins, which are inserted into the through holes of the monolithic circuit boards that have been used for the packaging of resistors and capacitors. Active components have been widely used in the past ten years.