Electrode plate, electrochemical device and safety coating
This application relates to an electrode plate, an electrochemical device and a safety coating. The electrode plate comprises a current collector, an electrode active material layer and a safety coating disposed between the current collector and the electrode active material layer. The safety coating layer comprises fluorinated polyolefin and/or chlorinated polyolefin polymer matrix, a conductive material and an inorganic filler. The electrode plate can quickly cut off the circuit when the electrochemical device (for example, a capacitor, a primary battery, or a secondary battery) is in a high temperature condition or an internal short circuit occurs, and thus it may improve the high temperature safety performance of the electrochemical device.
1. An electrode plate comprising a current collector, an electrode active material layer and a safety coating disposed between the current collector and the electrode active material layer, wherein the safety coating consists essentially of a polymer matrix, a conductive material and an inorganic filler, wherein the polymer matrix is fluorinated polyolefin and/or chlorinated polyolefin polymer matrix, wherein based on the total weight of the safety coating, the weight percentage of the polymer matrix is from 35 wt % to 75 wt %; the weight percentage of the conductive material is from 5 wt % to 25 wt %; and the weight percentage of the inorganic filler is from 10 wt % to 60 wt %; and the average particle diameter D of the inorganic filler is 100 nm≤D≤10 μm; and wherein the inorganic filler is selected from at least one of lithium cobalt oxide, lithium manganese oxide, lithium nickel oxide, lithium nickel manganese oxide, lithium nickel manganese cobalt oxide, lithium nickel manganese aluminum oxide, lithium iron phosphate, lithium vanadium phosphate, lithium cobalt phosphate, lithium manganese phosphate, lithium iron silicate, lithium vanadium silicate, lithium cobalt silicate, lithium manganese silicate, lithium titanate, or at least one of a conductive carbon coating modified above material or a conductive metal coating modified above material.
2. The electrode plate according to claim 1 , wherein the polymer matrix is selected from at least one of polyvinylidene fluoride (PVDF), carboxylic acid modified PVDF, acrylic acid modified PVDF, polyvinylidene chloride (PVDC), carboxylic acid modified PVDC, acrylic acid modified PVDC, PVDF copolymer and PVDC copolymer.
3. The electrode plate according to claim 1 , wherein the conductive material is selected from at least one of a conductive carbon-based material, a conductive metal material, and a conductive polymer material,
wherein the conductive carbon-based material is selected from at least one of conductive carbon black, acetylene black, graphite, graphene, carbon nanotubes, carbon nanofibers;
the conductive metal material is selected from at least one of Al powder, Ni powder, and gold powder; and
the conductive polymer material is selected from at least one of conductive polythiophene, conductive polypyrrole, and conductive polyaniline.
4. The electrode plate according to claim 1 , wherein the safety coating has a thickness H of 1 μm≤H≤20 μm.
5. The electrode plate according to claim 1 , wherein the safety coating has a thickness H of 3 μm≤H≤10 μm.
6. The electrode plate according to claim 1 , wherein the weight percentage of the polymer matrix is from 50 wt % to 75 wt %; the weight percentage of the conductive material is from 5 wt % to 15 wt %; and the weight percentage of the inorganic filler is from 15 wt % to 45 wt %.
7. The electrode plate according to claim 1 , wherein the average particle diameter D of the inorganic filler is 1 μm≤D≤6 μm.
8. The electrode plate according to claim 1 , wherein the plate is a positive electrode plate.
9. An electrochemical device comprising a positive electrode plate and a negative electrode plate, wherein the positive electrode plate and/or the negative electrode plate is the electrode plate according to claim 1 , and the electrochemical device is a capacitor, a primary battery or a secondary battery.
10. A safety coating for an electrode plate, consisting essentially of: a polymer matrix, a conductive material and an inorganic filler, wherein the polymer matrix is fluorinated polyolefin and/or chlorinated polyolefin polymer matrix, and wherein based on the total weight of the safety coating, the weight percentage of the polymer matrix is from 35 wt % to 75 wt %; the weight percentage of the conductive material is from 5 wt % to 25 wt %; and the weight percentage of the inorganic filler is from 10 wt % to 60 wt %; the average particle diameter D of the inorganic filler is 100 nm≤D≤10 μm.
11. The security coating for an electrode plate according to claim 10 , wherein the weight percentage of the polymer matrix is from 50 wt % to 75 wt %; the weight percentage of the conductive material is from 5 wt % to 15 wt %; and the weight percentage of the inorganic filler is from 15 wt % to 45 wt %.
12. The safety coating for an electrode plate according to claim 10 , wherein the inorganic filler has an average particle diameter D of 1 μm≤D≤6 μm.
13. The safety coating for an electrode plate according to claim 11 , wherein the inorganic filler has an average particle diameter D of 1 μm≤D≤6 μm.