Negative electrode, and secondary battery, battery module, and battery pack including the same
The present invention relates to a negative electrode and a secondary battery including the same, and particularly, to a negative electrode which includes a negative electrode active material layer including first active material particles each in the form of a secondary particle in which a plurality of primary particles are agglomerated; and second active material particles, wherein the second active material particles have an average particle size (D 50 ) equal to or less than an average particle size (D 50 ) of the primary particles, the first active material particle is artificial graphite, and the second active material particle is a graphite-based particle, and a secondary battery, a battery module, and a battery pack including the same.
1. A negative electrode comprising a negative electrode active material layer comprising:
first active material particles each in a form of a secondary particle in which a plurality of primary particles are agglomerated; and
second active material particles,
wherein the second active material particles have an average particle size (D 50 ) equal to or less than an average particle size (D 50 ) of the primary particles,
the first active material particle is artificial graphite,
the second active material particle is a graphite-based particle, and
wherein the second active material particles have an average particle size (D 50 ) of 10 μm to 12 μm.
2. The negative electrode of claim 1 , wherein the average particle size (D 50 ) of the second active material particles is 14% to 95% of the average particle size (D 50 ) of the primary particles.
3. The negative electrode of claim 1 , wherein the primary particles have an average particle size (D 50 ) of 5 μm to 20 μm.
4. The negative electrode of claim 1 , wherein the first active material particles have an average particle size (D 50 ) of 10 μm to 35 μm.
5. The negative electrode of claim 1 , wherein the first active material particles have a specific surface area of 1.3 m 2 /g to 1.5 m 2 /g.
6. The negative electrode of claim 1 , wherein the second active material particles have a specific surface area of 1.4 m 2 /g to 1.6 m 2 /g.
7. The negative electrode of claim 1 , wherein the second active material particles are included at 20 wt % to 90 wt % with respect to a total weight of the first active material particles and the second active material particles.
8. The negative electrode of claim 1 , wherein the total weight of the first active material particles and the second active material particles is 90 wt % to 99.9 wt % with respect to a total weight of the negative electrode active material layer.
9. The negative electrode of claim 1 , wherein the second active material particle is at least one selected from the group consisting of artificial graphite, natural graphite, graphitized carbon fiber, and graphitized mesocarbon microbeads.
10. A secondary battery comprising:
the negative electrode of claim 1 ;
a positive electrode;
a separator interposed between the positive electrode and the negative electrode; and
an electrolyte.
11. A battery module comprising the secondary battery of claim 10 as a unit cell.
12. A battery pack comprising the battery module of claim 11 and used as a power source for devices.
13. The battery pack of claim 12 , wherein the device is an electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, or a power storage device.