Aug. 20, 2020
During the charging process, part of the lithium ions in the lithium iron phosphate are extracted, transferred to the negative electrode through the electrolyte, and embedded in the negative electrode carbon material; at the same time , electrons are released from the positive electrode and reach the negative electrode from the external circuit to maintain the balance of the chemical reaction. During the discharge process, lithium ions are extracted from the negative electrode and reach the positive electrode through the electrolyte. At the same time, the negative electrode releases electrons and reaches the positive electrode from the external circuit to provide energy for the outside world. Lithium iron phosphate battery has the advantages of high working voltage, high energy density, long cycle life, good safety performance, low self-discharge rate and no memory effect.
Lifepo4 Ebike Battery
On the left of the Rechargeable Lifepo4 Battery is a positive electrode made of LiFePO4 material with an olivine structure, which is connected to the positive electrode of the battery by aluminum foil. On the right is the negative electrode of the battery composed of carbon (graphite), connected to the negative electrode of the battery by copper foil. In the middle is a polymer separator, which separates the positive electrode from the negative electrode. Lithium ions can pass through the separator but electrons cannot pass through the separator. The battery is filled with electrolyte, and the battery is hermetically sealed by a metal casing.
The charging and discharging reaction of Lifepo4 Ebike Battery is carried out between the two phases of LiFePO4 and FePO4. During the charging process, LiFePO4 gradually separates from the lithium ions to form FePO4, and during the discharge process, lithium ions are inserted into FePO4 to form LiFePO4.
When the battery is charged, lithium ions migrate from the lithium iron phosphate crystal to the crystal surface, under the action of the electric field force, enter the electrolyte, then pass through the diaphragm, and then migrate to the surface of the graphite crystal through the electrolyte, and then are embedded in the graphite lattice.
At the same time, electrons flow through the conductor to the aluminum foil collector of the positive electrode, flow through the tab, battery positive pole, external circuit, negative pole, and negative pole to the copper foil collector of the battery negative pole, and then flow to the graphite negative pole through the conductor. , To balance the negative electrode charge. After the lithium ions are deintercalated from the lithium iron phosphate, the lithium iron phosphate is converted into iron phosphate.
When the battery is discharged, lithium ions are extracted from the graphite crystal, enter the electrolyte, and then pass through the diaphragm, migrate to the surface of the lithium iron phosphate crystal through the electrolyte, and then re-embed in the lithium iron phosphate lattice.
At the same time, electrons flow through the conductor to the copper foil collector of the negative electrode, through the tab, battery negative pole, external circuit, positive pole, and positive pole to the aluminum foil collector of the battery positive pole, and then flow to the iron phosphate through the conductor. Lithium cathode balances the charge of the anode. After the lithium ions are inserted into the iron phosphate crystal, the iron phosphate is converted into lithium iron phosphate.
As a production tool, forklifts are used for a long time every day. The first thing to consider is safety. We can see that some vehicles use lead-acid batteries, which have no safety guarantee. There are many cases of battery spontaneous combustion and burning by impact. Another example is the continuous fire event of some lithium battery cars. The thermal runaway temperature of the ternary lithium battery is about 200℃. Once the heat reaches 200℃, it will explode and naturally, while the thermal runaway temperature of the lithium iron phosphate battery is 750℃. It burns for 30 minutes without exploding, and lithium iron phosphate is safer.
2. Long life
The life of lithium iron phosphate batteries is basically over 8 to 10 years, basically the same as that of vehicles, while the cycle life of ternary lithium batteries is generally only 1/3 to 1/2 of that of lithium iron phosphate.
3. Energy density
Energy density, as the name implies, is the energy that a unit weight of battery can hold. Energy density is usually an important indicator for judging the battery's superiority. Although the low energy density of lithium iron phosphate batteries is not an advantage, in the use of forklifts, because forklifts do not require compressed space like household vehicles, energy density is not very important in battery performance indicators. Important, on the contrary, the low energy density makes the price of lithium iron phosphate batteries low, so the low energy density feature becomes an advantage in the use of forklifts.
In summary, lithium iron phosphate battery is by far the best power battery in the forklift industry. All of the above are all related to the selection of battery cell types. With a good battery cell and a mature PACK solution, a complete power battery can be achieved.