Author ：Iflowpower – Portable Power Station Supplier
Every five cars failure is one of the batteries. In the future, with the increasing popularity of automotive technologies such as electrical transmission, launch / flameout engine management and hybrid (electricity / gas), this issue will become more and more serious. How to extend the life and reliability of the car battery? Every five car faults have been caused by the battery.
In the future, with the increasing popularity of automotive technologies such as electrical transmission, launch / flameout engine management and hybrid (electricity / gas), this issue will become more and more serious. In order to reduce the failure, the voltage, current, and temperature of the battery are accurately tested, and the results are pre-resolved, the charging state and the operating state are calculated, and the results are sent to the engine control unit (ECU), and the control charging function. Modern cars were born in the early 20th century.
The first car relies on manual startup. It is very powerful, there is a high risk, and this hand crank of the car has caused a lot of death. In 1902, the first battery started motor was successfully developed.
By 1920, all the cars have been started. The initial use is a dry battery. When electric energy is exhausted, it is not replaced.
Soon, the liquid battery (ie the ancient lead-acid battery) replaces the dry battery. The advantage of the lead-acid battery is to charge from medium when the engine is working. In the last century, there is almost no change in lead-acid batteries, and the last important improvement is sealing it.
True change is the needs of it. At first, the battery is only used to start the car, the horn and power supply for the lamp. Today, all electrical systems of the car must be powered before ignition.
A surge in new electronic devices are not just GPS and DVD players and other consumer electronic devices. Today, the engine control unit (ECU), the electric car window and the electric seat, and the body electronic device such as the electric seat has become a standard configuration of many basic models. The new load in the exponential level has been born seriously, and the failure caused by the electrical system is increasingly the evidence.
According to ADAC and RAC statistics, almost 36% of the car failure can be attributed to electrical failure. If the number is decomposed, it can be found that more than 50% of the fault is caused by the components of the lead-acid battery. Evaluation of the health of the battery The following key characteristics can reflect the health of the lead-acid battery: (1) Charging state (SOC): SOC indicates how much charge can be supplied, the battery rated capacity (i.
e., new battery's SOC) percentage representation. (2) Operation status (SOH): SOH indicates how much charge can be stored.
Charging state charging status indication is better than battery fuel gauge. There are many ways to calculate SOC, two of which have two: open circuit voltage measurement method and Coulomb assay (also known as Coulomb counting). (1) Open circuit voltage (VOC) measurement method: Condensed relationship between open circuit voltage and its charging state during battery-free.
This calculation method has two basic limits: one is to calculate the SOC, the battery is not open, and the load is not connected) Second, this measurement is only accurate after a considerable stability. These limitations make the VOC approach to calculate the online calculation SOC. This method is usually used in a car repair shop, where the battery is removed, and the voltage between the positive and negative electrical poles can be measured.
(2) Coulomb assay: This method uses Coulomb Count to take the current to time points, thus determining SOC. With this approach, you can calculate the SOC in real time, even if the battery is under load conditions. However, the error of the coulomb measurement will increase over time.
It is generally comprehensively using open circuit voltage and coulomb counting to calculate the charging state of the battery. The operating status of the running state reflects the general state of the battery, and its ability to store charge compared to new batteries. Due to the nature of the battery itself, SOH computing is very complicated, relying on the chemical composition and environment of battery.
The battery's SOH is affected by many factors, including charging acceptance, internal impedance, voltage, self-discharge and temperature. These factors are generally considered to be difficult to measure these factors in real-time environments in the automotive environment. In the startup phase (engine start), the battery is under the maximum load, at this time, the battery is most reflecting the SOH of the battery.
Bosch, Hella, etc. The actual SOC and SOH calculations actually used by the leading car battery sensor developers are highly confidential and are often protected by patent protection. As the owner of intellectual property, they usually work closely with VARTA and MOLL to develop these algorithms.
This circuit can be divided into three parts: (1) battery test battery voltage to test the resistive attenuator that is directly separated from the battery positive electrode. For the test current, put a test resistor (12V usually use 100M) between the negative electrode and the ground. In this configuration, the metal chassis of the car is generally, and the test resistor is installed in the current circuit of the battery.
In other configurations, the negative electrode of the battery is. About SOH calculation, not to test the temperature of the battery. (2) Microcontroller microcontroller or MCU important completion two tasks.
The first task is to solve the result of the analog to digital converter (ADC). This work may be simple, such as only basic filtering), may also be complex, such as calculating SOC and SOH. The actual function depends on MCU's resolution and needs of automakers.
The second task is to send the resolved data via the communication interface to the ECU. (3) Communication Interface Currently, the local interconnect network (Lin) interface is the most common communication interface between battery sensors and ECUs. Lin is a single line, low cost alternative to a wide-known CAN protocol.
This is the simplest configuration of battery testing. However, most precision battery test algorithms require both battery voltage and current, or by battery voltage, current and temperature. In order to make synchronous sampling, you have to add up to two analog to digital converters.
In addition, the ADC and MCUs adjust the power supply to work correctly, causing new circuit complexity. This has been processed by the LIN transceiver manufacturer by integrating the power supply. The next development of automotive precision battery testing is integrated with ADC, MCU and Lin transceivers, such as ADI's AduC703X Series Precision Simulation Microcontrollers.
AduC703X supplies two or three 8kSPs, 16-bit (Sigma) - (Delta) ADC, a 20.48MHzarm7TDMIMCU, and an integrated Linv2.0 compatible transceiver.
The ADUC703X series is integrated with a low pressure difference adjuster, which can be powered from lead-acid batteries. In order to meet the needs of automotive battery tests, the front end includes the following device: a voltage attenuator for monitoring the battery voltage) A programmable gain amplifier, when used with a 100m resistor, supports the full-scale current of 1A below 1500A) A accumulation Support coulomb count without software monitoring) and a single temperature sensor. A few years ago, only high-end cars were equipped with battery sensors.
Today, there are more and more medium and low-end cars installed in small electronic devices, and it can only be seen in high-end models ten years ago. The number of faults caused by lead-acid batteries is therefore constantly added. After a few years, each car will install the battery sensor, thereby reducing the risk of increasing the risk of failure.
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