Analysis of the background the premise of lithium battery protection circuit with low consumption

Source: 2020 - 04 - 14 18:57 hits: once the necessity of lithium battery protection circuit with constant progress and development of science and technology, more and more portable electronic products such as mobile phone, notebook computer, PDA, digital cameras and other appear constantly, rich and convenient for people's life greatly. Now these portable electronic devices has become an indispensable part of people's life, has a very broad market prospects and development space. As these electronic products to the development of miniaturization, lightweight, portable, the use of the power supply put forward higher requirements. Therefore, an urgent need to small volume, light weight, high energy density of the secondary battery. Compared with nickel cadmium battery and nickel metal hydride batteries, lithium batteries because of its small volume, light weight, large energy density, no memory effect, long service life and wide use range, high working voltage, low self-discharge rate and become the most widely used secondary battery. Of low power lithium battery protection circuit is introduced the background and significance due to the lithium battery energy density is high, the state is in charge, the battery temperature rise after the excess energy, so the electrolyte decomposition and produce gas, easy to make the internal pressure and the risk of spontaneous combustion or broken; On the contrary, in the condition of excessive discharge, the electrolyte decomposition leads to the deterioration of the battery characteristics and durability, reduced the number of rechargeable, shorten the service life of the battery. Therefore, the protection of lithium battery is very important, lithium battery applications must have a battery protection chip, prevent the battery overcharge, overdischarge and overcurrent. To sum up, lithium battery protection circuit design is very important. However, lithium battery protection circuit can increase the battery power of additional losses, reduce the time of the battery, which requires the lithium battery protection circuit to implement low power consumption in high precision. Lithium battery protection chip, besides the overcharge protection, discharge protection and over-current protection function, still should meet the following requirements, this is also the goal of the design of chip. ( 1) Ultra-low power consumption. Lithium battery protection circuit, power consumption is the battery wear. Therefore, we need to try to reduce the power consumption of lithium battery protection circuit. ( 2) Detecting voltage precision is high. In order to make the lithium battery protection circuit response correctly batteries of different working conditions, protection circuit must be able to accurately detect had charge voltage protection, over discharge protection voltage parameters such as voltage. ( 3) In the big voltage within the scope of work. Because lithium battery protection circuit of power supply voltage is the battery voltage, battery voltage can be in large range, so you need to lithium battery protection circuit work properly within the voltage range. Lithium battery protection circuit scheme in the use of various kinds of batteries, lithium batteries, Also known as lithium ion secondary battery or lithium ion battery) Is in recent decades developed a kind of new type power supply. Different from general chemical power supply, lithium battery charge and discharge process is embedded by the positive and negative of lithium ion batteries and remove. Lithium battery cathode carbon materials, such as graphite. The anode is lithium transition metal oxides, such as lithium cobalt oxide ( LiC002) 。 And the positive and negative material of lithium-ion batteries is the lithium ion embedded layered structure of the compounds, can be embedded lithium ion free and separation. Lithium ion between the layers in the proper electrolyte in the electrochemical reaction. When charging, lithium ion in the driving of the applied electric field, the escape from the positive lattice, through the electrolyte, embedded in the cathode lattice. Discharge process is on the contrary, the lithium ions back to the positive, electrons are passed via an external circuit to the anode with lithium ion compound.