Method of Detection System Based on LXI Bus

　　Author ：Iflowpower – Portable Power Station Supplier

The mobile phone lithium-ion battery explores the functional test for the packaged battery protection circuit, using the power supply, electronic load, multiplexing and digital multimeters and other instruments simulation of various charge and discharge, overcurrent, test battery protection Is the circuit effective. Eliminate battery products from the source from the source into the market. The detection of lithium-ion batteries is not effective for detecting the protection functions of the battery protection circuit.

The tight detection step of the battery detection system includes the following sections: 1) Conventional open voltage detection battery function detection, to perform a short time to charge the battery, and Measuring the open circuit voltage, determine whether the basic charging function of the battery is effective. 2) Overcurrent protection and recovery detection use electron load to make a large current discharge of the mobile phone, and detect the internal current cutoff function of its protection circuit. When cutting off the discharge circuit, the detection battery can restore normal work.

3) Work temperature detection reads the resistance value on the temperature sensor by multimeter, detecting the operating temperature of the battery. 4) Overcharge and recovery detection power supply to overwhelp the mobile phone, detect whether the battery protection circuit can cut off the charging loop. 5) Over-discharge and recovery detection of electronic loads over discharge the mobile phone battery, detect whether the battery protection circuit can cut off the discharge loop.

6) AC block detecting battery communication internal resistance by AC internal resistance. Typical lithium-ion battery detection system should include the following probe instruments: ● Multi-channel switch is used to load different incentives to be tested, and switch different detection equipment ● High-precision digital multimeter, complete DC voltage of the battery, Current and resistance detection ● Two way multiple power supplies for charging detection to the tape, and supply power to the probe fixture ● Electronic load, for discharge detection to the tape ● AC internal obstruction instrument for use Measure 1 kHz exchange in the exchange internal resistance ● Industrial computer and detection software, used to control equipment to complete overcurrent protection and recovery detection in lithium ion battery detection as an example, we describe a detailed detection process: detection system The computer, sequentially issues instructions to each instrument via the GPIB interface, control the detection process. First switch the multiplex switch, connect the electronic load to the to be tested.

Setting the electronic load in constant current mode, allowing a relatively large constant current (e.g., 5a) to turn on 20 ms, turn on the digital multi-purpose table and the battery output terminal, detect the battery The output voltage.

If the battery output voltage is 0, the battery protection circuit is started, and the battery output loop has been cut. This project detection is passed. If the results are not zero, this target is set to fail.

After the detection ends, quickly open the switch, cut off the connection between the electronic load and the battery, because long-term high current discharge may cause permanent damage to the battery. Based on the above detection method, 2007 Agilent launched a new generation of lithium-ion battery detection method. The new approach uses a large number of LXI (LanextensionsForinstrument) system probe instruments that have been launched in recent years, and these LXI instruments are compared to traditional products, and the system integration is simplified, and the detection speed is improved, and the system volume is greatly reduced.

And build costs. In the system, each instrument is connected to a computer through a network or a GPIB cable, which is formed into a hybrid detection system based on the LXI platform, and the entire system is only 14U. In the actual use of some mobile phone battery packages, customers tell us that new processing methods have reduced system volume than 1/3 compared to their original detection system configuration, and the cost reduction is more than 1/4, and the detection speed is also available.

10% of the improvement. In addition, smaller chassis volume, smaller system connection, and smaller power supply that switch power supplies, there is a lot of additional benefits. On the development of the probe software, the LXI instrument also supports various mainstream software development environments, and can write probes in various development environments such as VB, VC, C / C ++, LabVIEW, which are identical to traditional instrument control methods.

During the battery detection, the customer's most concerned issue In addition to ensuring battery quality, how to improve battery production, reduce processing cost. In addition, since the electrical characteristic indicators of different models, the detection system is not a certain flexibility in software and hardware, facilitating the secondary development of the customer. Finally, under the condition of continuing to turn on the processing line 24 hours a day, the quality, maintenance cost of the system instrument is a tight factor for the treatment of the battery detection system.

Detection system instrument selection battery detection system selection: In single-chip battery detection, multi-channel switch is desirable to connect to the battery to connect different load or power supply repeated charge and discharge detection, or use multiple switches to perform Measuring instrument switching. In the general battery detection process, the single-chip battery completes all the detection of about dozens of switched love to change, the processing line is usually above 8,000 pieces, and the opening closure of a single switch can reach more than 150,000 times in one day. So good switching quality, as well as fast switching rate, is the key to selecting switch products.

Agilent 34980a serves a variety of high quality switch cards. These switches are supplied in the same kind of products, the fastest turning time, as well as the longest switch life, and report the working state of each switch through the number of switches, in order to replace the switch to the failure. In addition, its built-in digital multimeter can complete high precision measurement of various DC signals.

Can save investment, improve system integration and detection speed. The selection of multiple power supplies in the battery detection system is in battery detection, and the power supply loaded on the to-pending will be more than two channels, remove the clamp to be tape, which is also used to charge the battery and simulate various kinds. Overvoltage, overcharge, and test battery protection circuitry.

When such detection, the power supply should be very critical, usually, the battery is not charged, and the time cannot exceed 1 second, otherwise the battery combustion explosion may be triggered, and in order to ensure the detection speed, this time is generally limited to hundreds of milliseconds. N6700 modular DC power supply, each power chassis can be placed in 1U height to set up more than 4 power modules, composed mutually independent multiplexing. In addition, these power modules have a built-in voltage current measurement function, which can monitor output states without switching to other measurement instruments.

In the automatic detection system, the modular power supply system can greatly reduce the multi-channel power supply volume, reduce the system cost, and become the preferred choice for the power supply of today's detection system. The selection electron load of the electronic load in the battery detection system is used to detect the discharge of the battery, and when the simulation battery is short-circuited, the internal protection circuit can cut off the battery output in time. In the battery detection process, the large current discharge time cannot exceed 30ms, otherwise it will cause an unexpected battery combustion or explosion, so in order to ensure the safety of the detection, such detection should be very high in electron load, and the speed of current change is very high.

Agilent supplies a variety of electronic load products, with fast current change speed, up to 107A / s. Built-in 16bit voltage current readback function, you can measure the voltage current value in the working state in real time without switching to other devices. The internal resistance value of the communication internal resistance meter is associated with the quality of the battery cell and the quality of the battery pack.

If the measured battery internal resistance is higher than the expected value, the battery quality is likely to have problems. Since the lithium ion battery is often accompanied by a dynamic load, it is often accompanied by a large number of current pulses, and the battery communication in 1 kHz has become an industry standard for battery internal resistance. The lower the battery internal resistance, the more stabilizing the voltage value of the battery output.

Therefore, the battery resistance of the battery under 1 kHz will be very powerful indicating that the battery is adjusted to its own output voltage under dynamic load. Agilent dynamic internal resistance instrument 4338B can help process problems on the interpretation of communication, supply high-speed accurate measurement results. Through the above instruments, you can set a highly efficient battery detection system very quickly.

Most of these instruments have good expansion capabilities, such as a 34980A switching system, can extend more measurement channels through a card, and the N6700 can increase the number of power supplies in the system in the power module or improve the power output power. This system also has a good expansion function. After a very simple modification, it can be used in other major capacity batteries, such as PDA, laptop, and digital camera.