Application of these high-performance charge and discharge methods in battery test equipment

　　Author ：Iflowpower – Portable Power Station Supplier

Battery detection equipment is an essential equipment and infrastructure in the battery manufacturing industry. With the use of electric vehicles, portable consumer electronics, the demand for lithium ion batteries is new, and the demand for lithium-ion battery detection equipment is also on the way. Battery detection equipment is used to verify the function and performance of the battery before shipping to customers.

After assembling the battery cell or battery pack, each unit is not at least a fully controlled charging or discharging cycle to initialize the device and convert it to a normal operating storage device. The important function of the battery detection device is to detect battery capacity, efficiency, magnification, high temperature performance, low temperature performance, storage performance and internal resistance, etc. And conversion efficiency.

About the core function of battery detecting equipment, there are two processing methods for the popularity of the market, and the digital methods implemented using the DSP and the simulation method of using discrete devices. Whether it is DSP method or discrete method has its own disadvantages, the software development difficulty of the DSP method is large, and the hardware development is difficult, resulting in two ways to design the design cycle, and the overall development cost is relatively high. In order to help battery detection equipment manufacturers reduce research and development time, the product can be quickly put into the market, and Ti has recently launched two high-performance, high integration, low-cost battery charge and discharge processing methods, respectively, for medium power (10A to 200A) and Small power (3A ~ 6A).

The first is for medium power, Ti's reference design is TIDA-01041x series. The TIDA-01041X series supplies 3 sets of methods for different current demand, respectively, TIDA-01040 (0 ~ 100A), TIDA-01042 (0 ~ 200A), all methods guaranteed = 0.02% Full amount recharge charging current accuracy and = 0.

01% charge and discharge voltage accuracy. As shown in the figure below, TIDA-01041X The entire system is important from four parts: the core device LM5170 (blue area) is responsible for power lifting step, important functions include multi-phase solution, direction switching, peak current control, anti-electricity inverting, etc. INA188 Instrument Amplifier is responsible for high-side constant current test; LM6142 is responsible for voltage amplification testing; ADS131A04 (24-bit High Precision ADC) and DAC80004 (16-bit High Precision DAC) are responsible for real-time reading and real-time settings of current voltages, can be supplied by TI Upper chart interface reading information and operation.

LM5170 is a star product of Ti, and it is also the core of the entire system. LM5170 internal integrated dual 5AMOSFET semi-bridge drive can supply up to 100A continued output current. At the same time, single LM5170 can support dual-phase intersection, which can effectively reduce the inductance value, capacitance capacitance value, and input output voltage ripple.

With regard to the use of the requirements higher than 100A, the LM5170 supports multiple mislapse parallel to supply larger current capabilities, and the following figure shows several multi-block parallel methods. In addition, relevant to the DSP method, the LM5170 is much faster due to the simultaneous support of peak current testing and uniform current test, and speeds and speeds. The lower image waveform is based on the TIDA-01041 (100A) evaluation board - 100A to + 100A current hopping detection (this waveform is one of the phase -25a ~ + 25a, 4 phase current sum: -100A ~ + 100A).

The blue signal is the direction of the DIR pin, the red color of the LM5170 reference signal Iseta, yellow is the output voltage Vout, green is IOUT current. From the figure below, we can see that the LM5170 should be only 400s under the -100A to + 100A current hopping conditions, far below the DSP method under the same detection conditions (usually above 5ms). TI needle about small power (= 6a) battery test uses high-precision low cost method PMP15043.

This method is important to three parts, TPS61178 boost DC / DC is responsible for discharge portions, TPS54821 buck DC / DC is responsible for charging part, current test is realized by INA188 meter amplifier, voltage test can be achieved by low cost play TLV07. At present, the high-power (= 6A) battery charge and discharge method is currently constructed by the devices, but with the market's accuracy and reliability requirements, the discrete method is getting more and more market. need.

TI needle about small power battery test equipment has introduced high-precision low cost method PMP15043, which is very good to handle these issues. As shown in the figure below, the PMP15043 method has several parts: TPS61178 boost DC / DC is responsible for discharge portions, TPS54821 buck DC / DC is responsible for charging part, current test is achieved by INA188 meter amplifier, voltage test can be released by low cost op amp TLV07 is implemented. The TPS61178 and TPS54821 integrate power MOSFET and drive circuits, which greatly simplifies the design of the power part, which can effectively reduce the debugging time of customers in discrete methods.

TPS61178 and TPS54821 are all very common Boost and Buck chips on the market, and the overall method is also quite competitive. PMP15043 is not only competitive in BOM cost, but also excellent performance. The picture below shows the charging and discharge current accuracy curve of PMP15043.

It can be seen that the accuracy can be guaranteed within 20,000 yuan, which is ideal for battery testing of cost and performance. In summary, whether it is about medium-high power usage scenarios (= 10a) or about small power usage scenarios (6a), TI can supply corresponding highest cost performance. View the specific design documentation and probe report by the following link.

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