First, the basic structure of the battery
The basic structure of the battery consists of batteries, protection board, shell three parts.
1, batteries: batteries are the most important part of the battery, is the energy conversion carrier. The current production of polymer lithium-ion batteries and cylindrical lithium-ion batteries. The basic parameters of batteries are: capacity, internal resistance, cycle life and so on.
2, the protection board: protection board is to protect the normal work of batteries to prevent the occurrence of abnormal electronic function module. The main components are IC and MOS tube. IC is to monitor the cell voltage components, MOS tube is a switch. In the whole module, IC by detecting the working circuit current and the voltage across the battery to control the MOS tube switch state, thus controlling the charge and discharge circuit, to prevent the battery overcharge, over discharge or over current purposes. The main parameters of the protection board are: overcharge protection voltage, overcharge protection recovery voltage, over discharge protection voltage, over discharge protection recovery voltage, short circuit protection current, consumption current, PCM internal resistance and so on. The above parameters can be measured by a dedicated device or analog circuit.
3, shell: shell is the battery and protective plate fixed together, sealed and with the host to complete the function of the shell. The shell is often divided into bottom shell and face shell. Generally with the host with the outside after the leakage for the face shell, the other for the bottom shell.
Shell commonly used materials are: ABS, ABS + PC, PC and so on. Measure the main indicators of the shell are: color, material, with, mechanical strength.
Second, the battery assembly of the key process
1, soldering: soldering is the use of solder wire to connect the conductors together, and to achieve a good conduction effect of the process. Factors affecting the quality of solder are welding temperature, the main material, solder materials. In the battery assembly welding temperature is generally required to control at 360 ± 10 ℃.
Easy to weld materials are gold, silver, copper, tin, nickel, steel and so on. Solder in the prone to the bad are: Weld, fake welding, welding and so on.
2, plastic shell package (also known as ultrasonic welding pressure): commonly used plastic shell package is the use of ultrasonic welding method, the principle is to use ultrasonic energy to the surface of the two contacts, contact part of the high-frequency vibration heat, The surface is melted and bonded.
The main parameters affecting the ultrasonic welding are: equipment power, equipment energy, pressure, welding time.
Third, the test
1, cell test: conventional items are: capacity, cycle life, internal resistance, voltage, self-discharge and so on. Other projects are: high temperature discharge performance, low temperature discharge performance, short circuit, sting and so on.
2, protection board: electrical performance test parameters are: overcharge protection voltage, overcharge protection recovery voltage, over discharge protection voltage, over discharge protection recovery voltage, short circuit protection current, power consumption, PCM resistance and so on. Shape structure: Goldfinger leakage part of the skew, subsidence, bright color without spots, gold layer thickness of 0.3μm.
3, finished battery: electrical performance testing items are: charge, discharge function, short circuit protection, open circuit voltage, overcurrent, identification resistance, thermistor, battery resistance and so on. Appearance and structure testing items are: kit effect, drop test, gap, color and so on.