Lithium ion battery

Abstract

The invention aims at providing a lithium ion by a compensation lithium cathode to compensate the loss of battery cathode capacity by an alloy anode. The characteristic of a silicon anode causes the low efficiency for compensating lithium to the lithium ion battery in a system for the first time which has large loss to the cathode capacity. The advantage of high energy density of the silicon anode battery can be highlighted by using the lithium ion provided by the compensation lithium cathode to compensate the loss of battery cathode capacity. Through the method of compensating lithium, lithium can be respectively compensated for twice to a cathode pole and an anode pole, thereby the method is capable of raising the capacity and performance of the battery.

Description

Technical field

[0001] The present invention relates to the technical field of lithium ion batteries, and in particular to a silicon anode system lithium ion battery in which an external lithium source is used to compensate for the capacity loss of the cathode. Background technique

[0002] As the energy density requirements of electronic products and electric vehicles increase, lithium-ion batteries with graphite anode systems whose energy density is close to the limit are gradually unable to meet the requirements. Silicon-based anodes with high capacity have become a hot topic in current research as a possible substitute for graphite. . For the silicon anode system, in addition to the irreversible capacity consumed by the SEI, the main reason is that the characteristics of the material make the lithium ions in the anode stay inside at the end of the full battery discharge and cannot form effective capacity, resulting in The cathode capacity is lost, the loss is about 20% ...

Examples

Embodiment 1

[0026] A lithium-ion battery, comprising a cathode, an anode, a separator between the cathode and anode, and an electrolyte thereof, and the cathode and the separator are laminated to prepare an electric core 363173 (length is 73mm, width is 31mm, thickness is 3.6mm ). The anode is a silicon-based anode, and 9um copper foil is used as a current collector. The formula of the slurry is: Si active material: SP: CMC: SBR = 90:2:4:4. The cathode formula is: lithium cobaltate:SP:PDVF=97:1.6:1.4.

[0027] The active material of the lithium-replenishing cathode is lithium cobaltate. The size of the lithium-replenishing cathode is 69mm long and 30mm wide, and it is placed close to the side of the battery cell. The lithium-supplementing cathode is arranged within a distance of 30 mm from the side of the battery cell, which is less than the width of the lithium-supplementing cathode.

[0028] The lithium-supplementing cathode performs lithium supplementation on the cathode and anode re...

Embodiment 2

[0034]The same cell as in Example 1. The active material of the lithium-replenishing cathode is lithium nickel manganese cobalt oxide, and the size of the lithium-replenishing cathode is 69 mm in length and 20 mm in width, and is placed close to the side of the cell. The lithium-replenishing cathode is arranged within a distance of 20 mm from the side of the cell, which is less than the width of the lithium-replenishing cathode.

[0035] Lithium-supplementing cathodes perform two lithium-supplementing operations on cathodes and anodes, respectively. For the first time, after the cell is activated and at 50% state of charge (SOC), the cathode is first supplemented with lithium, and the amount of lithium supplement is 1 / 3 of the total amount of lithium ions on the cathode, and then the anode is supplemented with lithium. , the amount of lithium replenishment is 1 / 6; after the first cycle of lithium replenishment is completed, the second lithium replenishment is performed, and t...

Embodiment 3

[0041] The same cell as in Example 1. The active material of the lithium-replenishing cathode is lithium manganate, and the size of the lithium-replenishing cathode is 69 mm in length and 10 mm in width, and it is placed close to the side of the battery cell. is smaller than the width of the lithium-supplemented cathode.

[0042] Lithium-supplementing cathodes perform two lithium-supplementing operations on cathodes and anodes, respectively. For the first time, after the cell is activated and at 50% state of charge (SOC), the cathode is first supplemented with lithium, and the amount of lithium supplement is 1 / 3 of the total amount of lithium ions on the cathode, and then the anode is supplemented with lithium. , the amount of lithium replenishment is 1 / 6; after the first cycle of lithium replenishment is completed, the second lithium replenishment is performed, and the cathode and anode are successively replenished with 1 / 3 and 1 / 6 of the capacity. The used lithium replenis...

Technical field

[0001] The present invention relates to the technical field of lithium ion batteries, and in particular to a silicon anode system lithium ion battery in which an external lithium source is used to compensate for the capacity loss of the cathode. Background technique

[0002] As the energy density requirements of electronic products and electric vehicles increase, lithium-ion batteries with graphite anode systems whose energy density is close to the limit are gradually unable to meet the requirements. Silicon-based anodes with high capacity have become a hot topic in current research as a possible substitute for graphite. . For the silicon anode system, in addition to the irreversible capacity consumed by the SEI, the main reason is that the characteristics of the material make the lithium ions in the anode stay inside at the end of the full battery discharge and cannot form effective capacity, resulting in The cathode capacity is lost, the loss is about 20% ...

Examples

Embodiment 1

[0026] A lithium-ion battery, comprising a cathode, an anode, a separator between the cathode and anode, and an electrolyte thereof, and the cathode and the separator are laminated to prepare an electric core 363173 (length is 73mm, width is 31mm, thickness is 3.6mm ). The anode is a silicon-based anode, and 9um copper foil is used as a current collector. The formula of the slurry is: Si active material: SP: CMC: SBR = 90:2:4:4. The cathode formula is: lithium cobaltate:SP:PDVF=97:1.6:1.4.

[0027] The active material of the lithium-replenishing cathode is lithium cobaltate. The size of the lithium-replenishing cathode is 69mm long and 30mm wide, and it is placed close to the side of the battery cell. The lithium-supplementing cathode is arranged within a distance of 30 mm from the side of the battery cell, which is less than the width of the lithium-supplementing cathode.

[0028] The lithium-supplementing cathode performs lithium supplementation on the cathode and anode re...

Embodiment 2

[0034]The same cell as in Example 1. The active material of the lithium-replenishing cathode is lithium nickel manganese cobalt oxide, and the size of the lithium-replenishing cathode is 69 mm in length and 20 mm in width, and is placed close to the side of the cell. The lithium-replenishing cathode is arranged within a distance of 20 mm from the side of the cell, which is less than the width of the lithium-replenishing cathode.

[0035] Lithium-supplementing cathodes perform two lithium-supplementing operations on cathodes and anodes, respectively. For the first time, after the cell is activated and at 50% state of charge (SOC), the cathode is first supplemented with lithium, and the amount of lithium supplement is 1 / 3 of the total amount of lithium ions on the cathode, and then the anode is supplemented with lithium. , the amount of lithium replenishment is 1 / 6; after the first cycle of lithium replenishment is completed, the second lithium replenishment is performed, and t...

Embodiment 3

[0041] The same cell as in Example 1. The active material of the lithium-replenishing cathode is lithium manganate, and the size of the lithium-replenishing cathode is 69 mm in length and 10 mm in width, and it is placed close to the side of the battery cell. is smaller than the width of the lithium-supplemented cathode.

[0042] Lithium-supplementing cathodes perform two lithium-supplementing operations on cathodes and anodes, respectively. For the first time, after the cell is activated and at 50% state of charge (SOC), the cathode is first supplemented with lithium, and the amount of lithium supplement is 1 / 3 of the total amount of lithium ions on the cathode, and then the anode is supplemented with lithium. , the amount of lithium replenishment is 1 / 6; after the first cycle of lithium replenishment is completed, the second lithium replenishment is performed, and the cathode and anode are successively replenished with 1 / 3 and 1 / 6 of the capacity. The used lithium replenis...

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