Lithium-ion battery
Provided is a lithium-ion battery, including a positive electrode plate, a separator, and a negative electrode plate. The separator is arranged between the positive electrode plate and the negative electrode plate. The positive electrode plate includes a positive electrode current collector and a positive electrode active layer laminated in sequence. A positive electrode active material in the positive electrode active layer includes lithium manganese iron phosphate and a ternary material. The negative electrode plate includes a negative electrode current collector and a negative electrode active layer laminated in sequence. The negative electrode active layer includes a composite layer and a lithium replenishing layer. A negative electrode active material in the composite layer includes a carbon material and SiO x . An areal density of lithium in the lithium replenishing layer is m 2 =a*M 1 *m 1 *δ*(1−η)/M 2 .
1 . A lithium-ion battery, comprising:
a positive electrode plate, a separator, and a negative electrode plate, wherein the separator is arranged between the positive electrode plate and the negative electrode plate;
the positive electrode plate comprises a positive electrode current collector and a positive electrode active layer laminated in sequence; a positive electrode active material in the positive electrode active layer comprises lithium manganese iron phosphate and a ternary material; based on the total mass of the positive electrode active material, a percentage by mass of the lithium manganese iron phosphate ranges from 78% to 83%, and a percentage by mass of the ternary material ranges from 17% to 22%;
the negative electrode plate comprises a negative electrode current collector and a negative electrode active layer laminated in sequence; the negative electrode active layer comprises a composite layer and a lithium replenishing layer; a negative electrode active material in the composite layer comprises a carbon material and SiO x ; based on the total mass of the negative electrode active material, a percentage by mass of the carbon material ranges from 83% to 88%, and a percentage by mass of the SiO x ranges from 12% to 17%; and an areal density of lithium in the lithium replenishing layer is m 2 =a*M 1 *m 1 *δ*(1−η)/M 2 ,
wherein m 2 is measured in g/dm 2 ; M 1 is a value of a specific discharge capacity of the SiO x , and the specific discharge capacity is measured in mAh/g; m 1 is a double-side areal density of the negative electrode plate, and m 1 is measured in g/dm 2 ; δ is a percentage by mass of the SiO x material in the negative electrode active material; η is first efficiency of a SiO x button half cell, wherein the first efficiency is a ratio of a first discharge capacity to a first charge capacity; M 2 is a value of a specific capacity of lithium, and the specific capacity is measured in mAh/g; and a value of a ranges from 1.05 to 1.15, and a value of x ranges from 0.6 to 1.5.
2 . The lithium-ion battery according to claim 1 , a double-side areal density of the positive electrode plate ranges from 4.5 g/dm 2 to 5.0 g/dm 2 , and a compaction density of the positive electrode plate ranges from 2.7 g/cm 3 to 2.8 g/cm 3 ; and the double-side areal density of the negative electrode plate ranges from 1.56 g/dm 2 to 1.92 g/dm 2 , and a compaction density of the negative electrode plate ranges from 1.60 g/cm 3 to 1.65 g/cm 3 .
3 . The lithium-ion battery according to claim 2 , wherein a general formula of the ternary material is LiNi a1 CO b1 X c1 O 2 ,
wherein 0≤a1≤1, 0≤b1≤1, 0≤c1≤1, a1+b1+c1=1, and X is at least one metal element in Group IIIB to group VA.
4 . The lithium-ion battery according to claim 2 , wherein a value of x ranges from 0.8 to 1.2.
5 . The lithium-ion battery according to claim 2 , wherein an injection coefficient of an electrolyte solution in the lithium-ion battery ranges from 2.9 to 3.2.
6 . The lithium-ion battery according to claim 2 , wherein the separator comprises a polymer layer, a ceramic layer and an adhesive layer laminated in sequence, a thickness of the polymer layer ranges from 5.5 μm to 9 μm, a thickness of the ceramic layer ranges from 1.0 μm to 3.0 μm, and a thickness of the adhesive layer ranges from 1.0 μm to 3.0 μm.
7 . The lithium-ion battery according to claim 1 , wherein a general formula of the ternary material is LiNi a1 CO b1 X c1 O 2 ,
wherein 0≤a1≤1, 0≤b1≤1, 0≤c1≤1, a1+b1+c1=1, and X is at least one metal element in Group IIIB to group VA.
8 . The lithium-ion battery according to claim 7 , wherein a value of x ranges from 0.8 to 1.2.
9 . The lithium-ion battery according to claim 7 , wherein an injection coefficient of an electrolyte solution in the lithium-ion battery ranges from 2.9 to 3.2.
10 . The lithium-ion battery according to claim 7 , wherein the separator comprises a polymer layer, a ceramic layer and an adhesive layer laminated in sequence, a thickness of the polymer layer ranges from 5.5 μm to 9 μm, a thickness of the ceramic layer ranges from 1.0 μm to 3.0 μm, and a thickness of the adhesive layer ranges from 1.0 μm to 3.0 μm.
11 . The lithium-ion battery according to claim 1 , wherein the carbon material comprises at least one of hard carbon and carbon-coated graphite secondary particle.
12 . The lithium-ion battery according to claim 11 , wherein a value of x ranges from 0.8 to 1.2.
13 . The lithium-ion battery according to claim 11 , wherein an injection coefficient of an electrolyte solution in the lithium-ion battery ranges from 2.9 to 3.2.
14 . The lithium-ion battery according to claim 11 , wherein the separator comprises a polymer layer, a ceramic layer and an adhesive layer laminated in sequence, a thickness of the polymer layer ranges from 5.5 μm to 9 μm, a thickness of the ceramic layer ranges from 1.0 μm to 3.0 μm, and a thickness of the adhesive layer ranges from 1.0 μm to 3.0 μm.
15 . The lithium-ion battery according to claim 1 , wherein a value of x ranges from 0.8 to 1.2.
16 . The lithium-ion battery according to claim 15 , wherein an injection coefficient of an electrolyte solution in the lithium-ion battery ranges from 2.9 to 3.2.
17 . The lithium-ion battery according to claim 15 , wherein the separator comprises a polymer layer, a ceramic layer and an adhesive layer laminated in sequence, a thickness of the polymer layer ranges from 5.5 μm to 9 μm, a thickness of the ceramic layer ranges from 1.0 μm to 3.0 μm, and a thickness of the adhesive layer ranges from 1.0 μm to 3.0 μm.
18 . The lithium-ion battery according to claim 1 , wherein an injection coefficient of an electrolyte solution in the lithium-ion battery ranges from 2.9 to 3.2.
19 . The lithium-ion battery according to claim 1 , wherein the separator comprises a polymer layer, a ceramic layer and an adhesive layer laminated in sequence, a thickness of the polymer layer ranges from 5.5 μm to 9 μm, a thickness of the ceramic layer ranges from 1.0 μm to 3.0 μm, and a thickness of the adhesive layer ranges from 1.0 μm to 3.0 μm.
20 . The lithium-ion battery according to claim 1 , wherein a thickness of the positive electrode current collector ranges from 7 μm to 13.5 μm, and a thickness of the negative electrode current collector ranges from 3.5 μm to 7 μm.