ELECTROCHEMICAL APPARATUS AND ELECTRONIC APPARATUS

Abstract

An electrochemical apparatus includes an electrolyte and a negative electrode plate. The negative electrode plate includes a negative electrode current collector and a negative electrode active material layer disposed on at least one surface of the negative electrode current collector. The negative electrode active material layer contains a negative electrode active material, and a tortuosity T of the negative electrode active material layer satisfies the following relation: 1 < T ≤ 2.5, where the tortuosity T is a ratio of a transmission path length Lt of the electrolyte in pores of the negative electrode active material layer to a thickness L0 of the negative electrode active material layer.

Description

Claims

1. An electrochemical apparatus, comprising: an electrolyte and a negative electrode plate; the negative electrode plate comprising a negative electrode current collector and a negative electrode active material layer disposed on at least one surface of the negative electrode current collector, and the negative electrode active material layer contains a negative electrode active material, wherein a tortuosity T of the negative electrode active material layer satisfies the following relation: 1 < T ≤ 2.5; wherein the tortuosity T is a ratio of a transmission path length Lt of the electrolyte through pores of the negative electrode active material layer to a thickness L0 of the negative electrode active material layer.

2. The electrochemical apparatus according to claim 1, wherein a porosity ε of the negative electrode active material layer satisfies: 20% ≤ ε ≤ 40%.

3. The electrochemical apparatus according to claim 1, wherein a compacted density PD g/cm3 of the negative electrode active material layer satisfies the following relation: 1.50 ≤ PD ≤ 1.75.

4. The electrochemical apparatus according to claim 1, wherein a sphericity S50 of particles of the negative electrode active material ranges from 0.70 to 0.90; wherein S50 represents a shape factor value when a cumulative particle volume distribution of the negative electrode active material is 50%; andthe sphericity is a ratio of a circular perimeter of an equivalent projected area of a particle to an actual perimeter of a projection of the particle.

5. The electrochemical apparatus according to claim 1, wherein Dv99 of particles of the negative electrode active material and L0 satisfies: 0.6L0 ≤ Dv99 ≤ 0.9L0.

6. The electrochemical apparatus according to claim 1, wherein Lt = 2 × (PD × Dv99) × (1 - ε); wherein PD is a value of a compacted density of the negative electrode active material layer with a unit of g/cm3 and ε is a porosity of the negative electrode active material layer.

7. The electrochemical apparatus according to claim 1, wherein 30 µm ≤ Dv99 ≤ 60 µm.

8. The electrochemical apparatus according to claim 1, wherein 30 µm ≤ L0 ≤ 140 µm.

9. The electrochemical apparatus according to claim 1, wherein a bonding force F between the negative electrode active material layer and the negative electrode current collector satisfies: F ≥ 6 N.

10. The electrochemical apparatus according to claim 1, wherein an OI value of the negative electrode plate satisfies: 5 ≤ OI value ≤ 15, wherein the OI value is calculated according to the formula: OI value = C004/C110; wherein C004 is a value of a characteristic peak area of the negative electrode plate at 54.30° to 54.60° as tested by X-ray diffraction spectroscopy, and C110 is a value of a characteristic peak area around 77.35° to 77.50° as tested by X-ray diffraction spectroscopy.

11. The electrochemical apparatus according to claim 1, wherein an areal density of the negative electrode active material layer is 0.035 mg/mm2 to 0.091 mg/mm2.

12. The electrochemical apparatus according to claim 1, wherein the electrolyte comprises a compound containing a sulfur-oxygen double bond; and the compound containing a sulfur-oxygen double bond comprises at least one of methylene methane disulfonate, propenyl-1,3-sultone, 1,3-propane disulfonic anhydride, 1,3-propane sultone, 2,4-butane sultone, or vinyl sulfate; and a percentage of the compound containing a sulfur-oxygen double bond is 0.1%-5% based on a weight of the electrolyte.

13. The electrochemical apparatus according to claim 1, wherein the electrolyte comprises lithium difluorophosphate, and a percentage of lithium difluorophosphate is below 1% based on a weight of the electrolyte.

14. An electronic apparatus, comprising: an electrochemical apparatus; the electrochemical apparatus comprising an electrolyte and a negative electrode plate; the negative electrode plate comprising a negative electrode current collector and a negative electrode active material layer disposed on at least one surface of the negative electrode current collector, and the negative electrode active material layer contains a negative electrode active material, wherein a tortuosity T of the negative electrode active material layer satisfies the following relation: 1 < T ≤ 2.5; wherein the tortuosity T is a ratio of a transmission path length Lt of the electrolyte through pores of the negative electrode active material layer to a thickness L0 of the negative electrode active material layer.

15. The electronic apparatus according to claim 14, wherein a porosity ε of the negative electrode active material layer satisfies: 20% ≤ ε ≤ 40%.

16. The electronic apparatus according to claim 14, wherein Lt = 2 × (PD × Dv99) × (1 -ε); wherein PD is a value of a compacted density of the negative electrode active material layer with a unit of g/cm3 and ε is a porosity of the negative electrode active material layer.

17. The electronic apparatus according to claim 14, wherein a compacted density PD g/cm3 of the negative electrode active material layer satisfies the following relation: 1.50 ≤ PD ≤ 1.75.

18. The electronic apparatus according to claim 14, wherein 30 µm ≤ Dv99 ≤ 60 µm.

19. The electronic apparatus according to claim 14, wherein 30 µm ≤ L0 ≤ 140 µm.