Anode for a cell of a lithium-ion battery, its manufacturing process and the battery incorporating it

Abstract

An anode usable in a cell of a lithium-ion battery comprising an electrolyte based on a lithium salt and a non-aqueous solvent, to a process for manufacturing this anode and to a lithium-ion battery having one or more cells incorporating this anode. This anode is based on a polymer composition, obtained by melt processing and without solvent evaporation, that is the product of a hot compounding reaction between an active material and additives having a polymer binder and an electrically conductive filler. The binder is based on at least one crosslinked elastomer and the additives furthermore include at least one non-volatile organic compound usable in the electrolyte solvent, the composition advantageously includes the active material in a mass fraction greater than or equal to 85%.

Claims

1. Process for manufacturing an anode usable in a cell of a lithium-ion battery comprising an electrolyte based on a lithium salt and a non-aqueous electrolyte solvent, the anode being based on a polymer composition obtained by melt processing and without solvent evaporation, that is the product of a hot compounding reaction between an active material and additives comprising a polymer binder and an electrically conductive filler, wherein said binder is based on at least one crosslinked elastomer and wherein said additives furthermore comprise at least one non-volatile organic compound which has a boiling point above 150 C. at an atmospheric pressure of 1.01310.sup.5 Pa, is in a solid state at room temperature and which is usable in said non-aqueous electrolyte solvent, the composition comprising said active material in a mass fraction greater than or equal to 85%, wherein said process comprises: a) melt compounding, without said solvent evaporation, in an internal mixer or an extruder, of said active material and said additives and said at least one organic compound in said solid state in order to obtain said composition in a crosslinkable state; and b) crosslinking and optionally hot forming said composition, in order to obtain a crosslinked composition.

2. Manufacturing process according to claim 1, wherein step a) is carried out by compounding said binder into a powder premix of other ingredients of the composition, at a temperature between 80 C. and 120 C. in an internal mixer.

3. Manufacturing process according to claim 2, wherein step b) is carried out by hot pressing said crosslinkable composition.

4. Manufacturing process according to claim 2, wherein the process then comprises a step c) of rolling said crosslinked composition so as to deposit it on a metallic current collector with which said anode is equipped.

5. Manufacturing process according to claim 2, wherein said active material comprises at least one compound or complex selected from the group consisting of graphite and a lithiated titanium oxide.

6. Manufacturing process according to claim 1, wherein step b) is carried out by hot pressing said crosslinkable composition.

7. Manufacturing process according to claim 1, wherein the process then comprises a step c) of rolling said crosslinked composition so as to deposit it on a metallic current collector with which said anode is equipped.

8. Manufacturing process according to claim 1, wherein said active material comprises at least one compound or complex selected from the group consisting of graphite and a lithiated titanium oxide.

Description

DETAILED DESCRIPTION

Example 1

(1) An anode polymer composition was prepared in a Haake internal mixer at 90 C., the composition having the following formulation expressed in mass fraction (%):

(2) TABLE-US-00001 HNBR binder (Therban 4307) 2.82 Carbon black 2.72 Ethylene carbonate 0.52 Active material Li.sub.4Ti.sub.5O.sub.12 93.84 Crosslinking system: Dicumyl peroxide 0.04 Triallyl cyanurate (TAC) 0.05

(3) The various compounds were introduced into this internal mixer in succession, starting with the hydrogenated nitrile rubber by way of a crosslinkable diene elastomer (HNBR binder), and then a premix in powder form of the other ingredients above. After this compounding, and hot pressing at 170 C. for 15 minutes simultaneously allowing the binder to be crosslinked, several electrodes having a thickness ranging from 0.4 mm to 2 mm, each able to form an anode inside a cell of a lithium-ion battery, after deposition on a current collector with which this anode is equipped, were obtained directly.

Example 2

(4) Another anode polymer composition based on the same ingredients as used in example 1 was prepared in a Haake internal mixer at 110 C., the composition however having the following different formulation expressed in mass fraction (%):

(5) TABLE-US-00002 HNBR binder (Therban 4307) 8.23 Carbon black 4.15 Ethylene carbonate 1.64 Active material Li.sub.4Ti.sub.5O.sub.12 85.69 Crosslinking system: Dicumyl peroxide 0.12 Triallyl cyanurate (TAC) 0.15

(6) The various compounds were introduced into this internal mixer in succession, starting with the hydrogenated nitrile rubber by way of a crosslinkable diene elastomer (HNBR binder), and then a premix in powder form of the other ingredients above. After this compounding, and hot pressing at 170 C. for 15 minutes simultaneously allowing the binder to be crosslinked, several electrodes having a thickness ranging from 0.4 mm to 2 mm, each able to form an anode inside a cell of a lithium-ion battery, after deposition on a current collector with which this anode is equipped, were obtained directly.

Example 3

(7) Another anode polymer composition based on an active material other than that used in examples 1 and 2, and on the same other ingredients used in these examples, was prepared in a Haake internal mixer at 110 C., the composition having the following different formulation expressed in mass fraction (%):

(8) TABLE-US-00003 HNBR binder (Therban 4307) 5.17 Carbon black 2.28 Ethylene carbonate 1.19 Active material (Timrex KS 6L graphite) 91.17 Crosslinking system: Dicumyl peroxide 0.08 Triallyl cyanurate (TAC) 0.11

(9) The various compounds were introduced into this internal mixer in succession, starting with the hydrogenated nitrile rubber by way of a crosslinkable diene elastomer (HNBR binder), and then a premix in powder form of the other ingredients above. After this compounding, and hot pressing at 170 C. for 15 minutes simultaneously allowing the binder to be crosslinked, several electrodes having a thickness ranging from 0.4 mm to 2 mm, each able to form an anode inside a cell of a lithium-ion battery, after deposition on a current collector with which this anode is equipped, were obtained directly.

(10) It will be noted, with reference to these exemplary embodiments of the invention, that the very high mass fraction (higher than 85%, indeed even higher than 90%) of the active material in this anode ensures that the or each cell thus obtained is a high-performance cell and therefore that the lithium-ion battery incorporating them is a high-performance battery.