From the source control of the electric car of the importance of lithium battery safety

In the lithium battery Production process, the evaluation The battery Capacity and performance is one of the very important link. From is mainly used in mobile phones, cameras, low capacity of hybrid electric vehicles (< 10 a), for the computer, electric motorcycles, electric cars in capacity (10 a and 30 a), and then to used for electric vehicles (30-120 - a) a high capacity Lithium ion batteries, without exception, all need to test to the factory to use.

According to the system application engineer Li Qiangde ADI company in Asia Pacific, precision instrument sales department, the industry is the most common practice for small capacity battery USES the linear test equipment for testing, though inefficient, accuracy is not high also, but still acceptable. But if the test equipment is also used for high capacity battery test, it will consume a large amount of power in the charging stage, lead to low efficiency, and it will bring serious cases of thermal dissipation equipment hardware design.

Therefore, ADI in specially designed for low, medium and high capacity Lithium electricity Pool points RongHuaCheng equipment AD8450/1 precision analog front end and controller and ADP1972 buck/boost PWM controller, abandon the traditional battery energy discharge to impedance load of linear structure, in turn, by using the PWM controller provides current and guide them back to the grid or for other battery, attaining the aim of efficient environmental protection.

How to go from source control electric cars, the safety of lithium-ion batteries and accurate

Test data shows that the charging mode, when the voltage of 3.5 V, 20 a, the efficiency of the value of 88%, the efficiency of 10 a value of 90%;And under the mode of discharge, when the voltage is 3 v, 20 a, the efficiency of the value of 89%, the efficiency of 10 a value of 92%.In addition to the efficiency of lithium battery business is more concerned about the cost and reliability. Li qiang said, lithium battery test on the market plan, also has a discrete device combination may be used more than ten of the device. And ADI this solution only AD8450/1 and ADP1972 two chips, highly integrated, greatly reduce the design size. And by moving the switch frequency up to 300 KHZ, Shared between multiple channels cost lower precision DAC and ADC, join the phase shift between channel synchronization can reduce the input filter, such as to reduce the total system cost.ADI also provide users with all reference design, design tools and maximum reduce development cost and the difficulty of design, shorten the development cycle.

How to realize the sharing DAC and ADC between multiple channels?

Above contains two functions: one is the battery, the second is the battery discharge, it is decided by AD8450/1 and ADP1972 mode signal. Each function has two modes: constant current (CC) mode and constant voltage (CV) mode. Two DAC channel control CC and CV set point.CC set-point decided to charge and discharge two functions of CC how many current mode circuits. From CC CV set-point decided to loop into the CV when battery voltage, also apply to the charging and discharging two functions.

Precision analog front end and the controller AD8450/1 using differential amplifier inside PGDA to measure battery voltage, and use the internal instrumentation amplifier PGIA and external shunt resistance (RS) current on the measuring cell. Then it through external and internal error amplifier compensation network (function is used to determine the loop CC or CV), the current and voltage compared with DAC set point. After the module, the output of the error amplifier into PWM controller ADP1972, to determine the duty ratio of power levels of MOSFET. Finally, form a complete loop inductance and capacitance. This section of the specification for charging and discharging two functions, because ADP1972 is buck and boost PWM controller.

The page contains the contents of the machine translation.