Method of producing lithium-ion battery

Patent metadata

Field	Value
Publication number	US-11658353-B2
Application number	US-202017108100-A
Country	US
Kind code	B2
Filing date	Dec 1, 2020
Priority date	Dec 11, 2019
Publication date	May 23, 2023
Grant date	May 23, 2023

Abstract

A negative electrode active material includes graphite and silicon oxide. On a rectangular coordinate system having an SOC of the battery on a horizontal axis and a dimension of the battery on a vertical axis, a charging profile of the battery includes a first stage and a second stage. When the battery is charged at a current rate equal to or higher than an inherent current rate, a first slope is less steep than a second slope. When the battery is charged at a current rate lower than the inherent current rate, the first slope is steeper than the second slope. During the initial charging, at least charging in the first stage is performed at a current rate lower than the inherent current rate. After the initial charging proceeds to the second stage, the thermal aging is performed at an SOC included in the second stage.

First claim

What is claimed is:

1. A method of producing a lithium-ion battery, comprising:
assembling a battery;
performing initial charging of the battery; and
performing thermal aging of the battery,
the battery including a negative electrode active material,
the negative electrode active material including graphite and silicon oxide,
wherein a charging profile of the battery is indicated on a rectangular coordinate system having a state of charge of the battery on a horizontal axis and a dimension of the battery on a vertical axis, wherein
the charging profile of the battery has a first stage and a second stage,
the second stage has a higher state of charge compared to the first stage, and
the charging profile has a first slope in the first stage and has a second slope in the second stage,

the battery having a boundary current rate at which the charging profile changes from the first stage to the second stage, wherein
when the battery is charged at a current rate equal to or higher than the boundary current rate, the first slope is less steep than the second slope, and
when the battery is charged at a current rate lower than the boundary current rate, the first slope is steeper than the second slope,

during the initial charging, at least charging in the first stage being performed at a current rate lower than the boundary current rate,
the first stage being completed when lithium insertion into the silicon oxide is saturated, and
after the initial charging proceeds to the second stage, the thermal aging being performed at a state of charge included in the second stage.

2. The method of producing a lithium-ion battery according to claim 1 , wherein, after the initial charging proceeds to the second stage, charging is performed at a current rate equal to or higher than the boundary current rate.

3. The method of producing a lithium-ion battery according to claim 1 , wherein the second stage is completed when the state of charge of the battery is 100%.

4. The method of producing a lithium-ion battery according to claim 1 , wherein the thermal aging is performed in an environment of from 40° C. to 80° C. for from 6 hours to 120 hours.

Assignees

• Toyota Motor Co Ltd

Inventors

• Iguchi Hiroki

Classifications

• H01M10/058 Primary

  Construction or manufacture · CPC title

• H01M4/133

  Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx · CPC title

• H01M4/364

  as mixtures · CPC title

• H01M2004/027

  Negative electrodes · CPC title

• H01M4/0461

  Electrochemical alloying · CPC title