Secondary battery, and battery module, battery pack, and device having same
A secondary battery includes a positive electrode sheet which includes a positive-electrode current collector, a positive-electrode active material layer, and a coating layer arranged between the positive-electrode current collector and the positive-electrode active material layer. The coating layer includes a conductive agent and a copolymer.
1. A secondary battery comprising:
a positive electrode sheet including:
a positive-electrode current collector;
a positive-electrode active material layer; and
a coating layer arranged between the positive-electrode current collector and the positive-electrode active material layer;
wherein:
the coating layer includes a conductive agent and a copolymer, and the copolymer includes: structural unit (I), structural unit (II), and structural unit (III) as follows:
in the structural unit (I):
R 1 and R 2 each independently represent a hydrogen atom, an unsubstituted or substituted alkyl group having 1-10 carbon atoms, an unsubstituted or substituted alkoxy group having 1-10 carbon atoms, or an unsubstituted or substituted alkenyl group having 1-10 carbon atoms, and
a substituent for the substituted alkyl group having 1-10 carbon atoms, the substituted alkoxy group having 1-10 carbon atoms, and the substituted alkenyl group having 1-10 carbon atoms in R 1 and R 2 is at least one selected from hydroxyl, amino, amide, cyano, and carboxyl,
in the structural unit (II):
R 3 represents a hydrogen atom, an unsubstituted or substituted alkyl group having 1-10 carbon atoms, an unsubstituted or substituted alkoxy group having 1-10 carbon atoms, an unsubstituted or substituted alkenyl group having 1-10 carbon atoms, or an aryl group having 5-20 carbon atoms, and a substituent for the substituted alkyl group having 1-10 carbon atoms, the substituted alkoxy group having 1-10 carbon atoms, and the substituted alkenyl group having 1-10 carbon atoms in R 3 is at least one selected from halogen, hydroxyl, amino, amide, cyano, and carboxyl,
R 4 represents a hydrogen atom, an unsubstituted or substituted alkyl group having 1-10 carbon atoms, an inorganic metal ion, or —R 10 NR 11 R 12 , a substituent for the substituted alkyl group having 1-10 carbon atoms in R 4 is at least one selected from halogen, hydroxyl, amino, amide, cyano, and carboxyl, and the inorganic metal ion is a sodium ion, a potassium ion, a lithium ion, a calcium ion, or a magnesium ion,
R 10 represents an unsubstituted or substituted alkylene group having 1-10 carbon atoms or an unsubstituted or substituted alkenylene group having 2-10 carbon atoms, and a substituent for the substituted alkylene group having 1-10 carbon atoms and the substituted alkenylene group having 2-10 carbon atoms in R 10 is at least one selected from halogen, hydroxyl, amino, amide, cyano, and carboxyl, and
R 11 and R 12 each independently represent an unsubstituted or substituted alkyl group having 1-10 carbon atoms, an unsubstituted or substituted alkenyl group having 1-10 carbon atoms or an aryl group having 5-20 carbon atoms, and a substituent for the substituted alkyl group having 1-10 carbon atoms and the substituted alkenyl group having 1-10 carbon atoms in R 11 and R 12 is at least one selected from halogen, hydroxyl, amino, amide, cyano and carboxyl, and in the structural unit (III):
R 5 and R 6 each independently represent a hydrogen atom, an unsubstituted or substituted alkyl group having 1-10 carbon atoms, X − represents an anion selected from a halogen ion, a sulfate ion, and a sulfonate ion, and a substituent for the substituted alkyl group having 1-10 carbon atoms in R 5 and R 6 is at least one selected from halogen, hydroxyl, amino, amide, cyano, and carboxyl.
2. The secondary battery of claim 1 , wherein:
in the coating layer, a content of the copolymer is more than 50 wt %.
3. The secondary battery of claim 1 , wherein:
a thickness of the coating layer is 0.1-20 μm.
4. The secondary battery of claim 1 , wherein:
the conductive agent includes at least one of conductive graphite, conductive carbon black, Ketjen black, acetylene black, carbon fiber, carbon nanotube, or graphene.
5. The secondary battery of claim 1 , wherein:
the coating layer further includes a binder, the binder including at least one of styrene-acrylic emulsion, sodium carboxymethyl cellulose, polyvinyl alcohol, polyacrylamide, or polyacrylate.
6. The secondary battery of claim 1 , wherein:
the copolymer satisfies 60%≤a/(a+b+c)×100%, where a denotes an average molar number of monomers of the structural unit (I), b denotes an average molar number of monomers of the structural unit (II), and c denotes an average molar number of monomers of the structural unit (III).
7. The secondary battery of claim 1 , wherein:
the copolymer satisfies: b/(a+b+c)×100%≤20%, where a denotes an average molar number of monomers of the structural unit (I), b denotes an average molar number of monomers of the structural unit (II), and c denotes an average molar number of monomers of the structural unit (III).
8. The secondary battery of claim 1 , wherein:
the copolymer satisfies: c/(a+b+c)×100%≤20%, where a denotes an average molar number of monomers of the structural unit (I), b denotes an average molar number of monomers of the structural unit (II), and c denotes an average molar number of monomers of the structural unit (III).
9. The secondary battery of claim 1 , wherein: in the structural unit (I), R1 and R2 each independently are the hydrogen atom, or the unsubstituted or substituted alkyl group having 1-10 carbon atoms.
10. The secondary battery of claim 1 , wherein in the structural unit (II): R3 is the hydrogen atom, or the unsubstituted or substituted alkyl group having 1-10 carbon atoms; and R4 is the hydrogen atom, an inorganic metal ion, or the unsubstituted or substituted alkyl group having 1-10 carbon atoms.
11. The secondary battery of claim 1 , wherein in the structural unit (III): R5 and R6 each independently are the hydrogen atom, or the unsubstituted or substituted alkyl group having 1-10 carbon atoms; and X − is the anion selected from the halogen ion.
12. The secondary battery of claim 1 , wherein:
the structural unit (I), structural unit (II), and structural unit (III) are copolymerized in a random or block manner.
13. The secondary battery of claim 1 , wherein:
the copolymer has a number average molecular weight of 10,000 to 100,000.
14. A battery module comprising a secondary battery including:
a positive electrode sheet including:
a positive-electrode current collector;
a positive-electrode active material layer; and
a coating layer arranged between the positive-electrode current collector and the positive-electrode active material layer;
wherein:
the coating layer includes a conductive agent and a copolymer, and the copolymer includes: structural unit (I), structural unit (II), and structural unit (III) as follows:
in the structural unit (I):
R 1 and R 2 each independently represent a hydrogen atom, an unsubstituted or substituted alkyl group having 1-10 carbon atoms, an unsubstituted or substituted alkoxy group having 1-10 carbon atoms, or an unsubstituted or substituted alkenyl group having 1-10 carbon atoms, and
a substituent for the substituted alkyl group having 1-10 carbon atoms, the substituted alkoxy group having 1-10 carbon atoms, and the substituted alkenyl group having 1-10 carbon atoms in R 1 and R 2 is at least one selected from hydroxyl, amino, amide, cyano, and carboxyl,
in the structural unit (II):
R 3 represents a hydrogen atom, an unsubstituted or substituted alkyl group having 1-10 carbon atoms, an unsubstituted or substituted alkoxy group having 1-10 carbon atoms, an unsubstituted or substituted alkenyl group having 1-10 carbon atoms, or an aryl group having 5-20 carbon atoms, and a substituent for the substituted alkyl group having 1-10 carbon atoms, the substituted alkoxy group having 1-10 carbon atoms, and the substituted alkenyl group having 1-10 carbon atoms in R 3 is at least one selected from halogen, hydroxyl, amino, amide, cyano, and carboxyl,
R 4 represents a hydrogen atom, an unsubstituted or substituted alkyl group having 1-10 carbon atoms, an inorganic metal ion, or —R 10 NR 11 R 12 , a substituent for the substituted alkyl group having 1-10 carbon atoms in R 4 is at least one selected from halogen, hydroxyl, amino, amide, cyano, and carboxyl, and the inorganic metal ion is a sodium ion, a potassium ion, a lithium ion, a calcium ion, or a magnesium ion,
R 10 represents an unsubstituted or substituted alkylene group having 1-10 carbon atoms or an unsubstituted or substituted alkenylene group having 2-10 carbon atoms, and a substituent for the substituted alkylene group having 1-10 carbon atoms and the substituted alkenylene group having 2-10 carbon atoms in R 10 is at least one selected from halogen, hydroxyl, amino, amide, cyano, and carboxyl, and
R 11 and Rig each independently represent an unsubstituted or substituted alkyl group having 1-10 carbon atoms, an unsubstituted or substituted alkenyl group having 1-10 carbon atoms or an aryl group having 5-20 carbon atoms, and a substituent for the substituted alkyl group having 1-10 carbon atoms and the substituted alkenyl group having 1-10 carbon atoms in R 11 and R 12 is at least one selected from halogen, hydroxyl, amino, amide, cyano and carboxyl, and in the structural unit (III):
R 5 and R 6 each independently represent a hydrogen atom, an unsubstituted or substituted alkyl group having 1-10 carbon atoms, X − represents an anion selected from a halogen ion, a sulfate ion, and a sulfonate ion, and a substituent for the substituted alkyl group having 1-10 carbon atoms in R 5 and R 6 is at least one selected from halogen, hydroxyl, amino, amide, cyano, and carboxyl.
15. A battery pack comprising the battery module of claim 14 .
16. A device comprising a secondary battery including:
a positive electrode sheet including:
a positive-electrode current collector;
a positive-electrode active material layer; and
a coating layer arranged between the positive-electrode current collector and the positive-electrode active material layer;
wherein:
the coating layer includes a conductive agent and a copolymer, and the copolymer includes: structural unit (I), structural unit (II), and structural unit (III) as follows:
in the structural unit (I):
R 1 and R 2 each independently represent a hydrogen atom, an unsubstituted or substituted alkyl group having 1-10 carbon atoms, an unsubstituted or substituted alkoxy group having 1-10 carbon atoms, or an unsubstituted or substituted alkenyl group having 1-10 carbon atoms, and
a substituent for the substituted alkyl group having 1-10 carbon atoms, the substituted alkoxy group having 1-10 carbon atoms, and the substituted alkenyl group having 1-10 carbon atoms in R 1 and R 2 is at least one selected from hydroxyl, amino, amide, cyano, and carboxyl,
in the structural unit (II):
R 3 represents a hydrogen atom, an unsubstituted or substituted alkyl group having 1-10 carbon atoms, an unsubstituted or substituted alkoxy group having 1-10 carbon atoms, an unsubstituted or substituted alkenyl group having 1-10 carbon atoms, or an aryl group having 5-20 carbon atoms, and a substituent for the substituted alkyl group having 1-10 carbon atoms, the substituted alkoxy group having 1-10 carbon atoms, and the substituted alkenyl group having 1-10 carbon atoms in R 3 is at least one selected from halogen, hydroxyl, amino, amide, cyano, and carboxyl,
R 4 represents a hydrogen atom, an unsubstituted or substituted alkyl group having 1-10 carbon atoms, an inorganic metal ion, or —R 10 NR 11 R 12 , a substituent for the substituted alkyl group having 1-10 carbon atoms in R 4 is at least one selected from halogen, hydroxyl, amino, amide, cyano, and carboxyl, and the inorganic metal ion is a sodium ion, a potassium ion, a lithium ion, a calcium ion, or a magnesium ion,
R 10 represents an unsubstituted or substituted alkylene group having 1-10 carbon atoms or an unsubstituted or substituted alkenylene group having 2-10 carbon atoms, and a substituent for the substituted alkylene group having 1-10 carbon atoms and the substituted alkenylene group having 2-10 carbon atoms in R 10 is at least one selected from halogen, hydroxyl, amino, amide, cyano, and carboxyl, and
R 11 and R 12 each independently represent an unsubstituted or substituted alkyl group having 1-10 carbon atoms, an unsubstituted or substituted alkenyl group having 1-10 carbon atoms or an aryl group having 5-20 carbon atoms, and a substituent for the substituted alkyl group having 1-10 carbon atoms and the substituted alkenyl group having 1-10 carbon atoms in R 11 and R 12 is at least one selected from halogen, hydroxyl, amino, amide, cyano and carboxyl, and in the structural unit (III):
R 5 and R 6 each independently represent a hydrogen atom, an unsubstituted or substituted alkyl group having 1-10 carbon atoms, X − represents an anion selected from a halogen ion, a sulfate ion, and a sulfonate ion, and a substituent for the substituted alkyl group having 1-10 carbon atoms in R 5 and R 6 is at least one selected from halogen, hydroxyl, amino, amide, cyano, and carboxyl.