阅读说明：本技术 一种锂离子电池及其陈化化成方法 (Lithium ion battery and aging method thereof ) 是由 许晓婵 张宝华 娄勇刚 金鑫 张巧灵 周帅 于 2019-08-29 设计创作，主要内容包括：一种锂离子电池及其陈化化成方法,包括电芯陈化、化成：电芯常温陈化,电芯放入常温陈化室进行常温陈化,温度范围：15℃~30℃,时间范围：12h~24h；电芯高温陈化,电芯从常温陈化室转入高温陈化室进行高温陈化,温度范围：30℃~85℃,时间范围：4h~12h；电芯在常温陈化、高温陈化阶段均放置在振动设备上振动,振动方向沿电芯厚度方向进行；电芯化成,化成加压范围：0.2Mpa~0.8Mpa,化成温度范围：30℃~85℃,化成温度与高温陈化温度保持一致,化成压力温度达到要求后对电芯进行梯度式逐渐增大电流式充电,本发明减少陈化时间从而缩短电池生产周期,而且可明显改善电池的一致性及高温循环性能。(A lithium ion battery and an aging formation method thereof comprise the following steps: the method comprises the following steps of (1) aging the battery cell at normal temperature, putting the battery cell into a normal-temperature aging chamber for normal-temperature aging, wherein the temperature range is as follows: 15-30 ℃, time range: 12 h-24 h; and (3) high-temperature aging of the battery cell, wherein the battery cell is shifted from a normal-temperature aging chamber to a high-temperature aging chamber for high-temperature aging, and the temperature range is as follows: 30-85 ℃, and the time range is as follows: 4 h-12 h; the battery cell is placed on vibration equipment to vibrate in the normal-temperature aging stage and the high-temperature aging stage, and the vibration direction is carried out along the thickness direction of the battery cell; formation of the battery core, formation pressurization range: 0.2 Mpa-0.8 Mpa, and the formation temperature range is as follows: the temperature is 30-85 ℃, the formation temperature is consistent with the high-temperature aging temperature, and the cell is charged in a gradient gradually increasing current mode after the formation pressure temperature meets the requirement.)

1. An aging and formation method of a lithium ion battery comprises the steps of battery core aging and formation, and is characterized in that:

step 1), normal-temperature aging of the battery core, putting the battery core into a normal-temperature aging chamber for normal-temperature aging, wherein the temperature range is as follows: 15-30 ℃, time range: 12 h-24 h; the electric core is arranged on a vibration device in a normal-temperature aging chamber to vibrate, and the vibration frequency range is as follows: 5 Hz-30 Hz, amplitude range: 1.0-3.0 mm, vibration time range: 10 min-30 min, vibration time interval range: 2 h-4 h;

step 2), high-temperature aging of the battery cell, wherein the battery cell is switched from a normal-temperature aging chamber to a high-temperature aging chamber for high-temperature aging, and the temperature range is as follows: 30-85 ℃, and the time range is as follows: 4 h-12 h; the electric core is arranged on a vibrating device in a high-temperature aging chamber to vibrate, and the vibration frequency range is as follows: 5 Hz-30 Hz, amplitude range: 1.0-3.0 mm, vibration time range: 10 min-30 min, vibration time interval range: 2 h-4 h;

step 3), cell formation, wherein the formation pressurization range is as follows: 0.2 Mpa-0.8 Mpa, and the formation temperature range is as follows: and (3) at 30-85 ℃, after the formation pressure temperature meets the requirement, carrying out gradient gradually-increasing current type charging on the battery cell, and specifically, comprising the following steps:

the first stage is as follows: constant-current charging, wherein the charging is carried out until the reversible capacity is 10% -15%, and the charging current range is as follows: 0.02C-0.05C, charging time: 2.0-7.5 h;

and a second stage: constant-current charging, wherein the charging is carried out until the reversible capacity is 20% -35%, and the charging current range is as follows: 0.05C-0.4C, charging time: 0.5-7.0 h;

and a third stage: constant-current charging, wherein the charging is carried out until the reversible capacity is 30% -50%, and the charging current range is as follows: 0.2C-0.6C, charging time: 0.5-2.5 h.

2. The aging method for a lithium ion battery according to claim 1, wherein: in the step 1) and the step 2), the vibration of the battery cell is along the thickness direction of the battery cell.

3. The aging method for lithium ion batteries according to claim 1, wherein the formation temperature is in accordance with a high-temperature aging temperature.

4. A lithium ion battery prepared by the aging method for a lithium ion battery of claim 1.

Technical Field

The invention belongs to the technical field of lithium ion battery manufacturing. In particular to a lithium ion battery and an aging method thereof.

Background

Nowadays, with the rapid development of global economy, not only is convenient and rapid life brought to human beings, but also serious pollution is brought, and the ecological environment is damaged and the health of the human beings is harmed due to the large discharge of pollutants. Meanwhile, petrochemical energy mainly comprising petroleum, coal and natural gas, which supports the high-speed development of human civilization in the 20 th century, has an unprecedented crisis, and the development of new energy is urgent in order to take a sustainable development way and protect the global ecological environment on which human beings rely for survival.

In the automobile industry, people are called to open a new generation of walking tool, namely a new energy automobile, which maintains the sustainable development of human beings and is in a peaceful place with the environment, a power battery is used as a power source of the new energy automobile, and the quality of the battery performance is related to the length of the driving range of the whole automobile and the service life of a product. The lithium ion battery is the first choice of the power battery due to the advantages of long cycle life, high energy density, no memory effect, environmental friendliness and the like. At present, the common problems of the lithium ion battery are long manufacturing period, poor battery core consistency and poor cycle performance.

Disclosure of Invention

The invention aims to provide an aging method of a lithium ion battery, which shortens the aging time of the lithium ion battery and improves the consistency and the high-temperature cycle life of the battery.

The invention also aims to provide the lithium ion battery prepared by the aging method of the lithium ion battery.

The technical scheme of the invention is as follows: the method comprises the following steps of cell aging and formation:

step 1), normal-temperature aging of the battery core, putting the battery core into a normal-temperature aging chamber for normal-temperature aging, wherein the temperature range is as follows: 15-30 ℃, time range: 12 h-24 h; the electric core is arranged on a vibration device in a normal-temperature aging chamber to vibrate, and the vibration frequency range is as follows: amplitude range of 5 Hz-30 Hz: 1.0-3.0 mm, vibration time range: 10 min-30 min, vibration time interval range: 2 h-4 h;

step 2), high-temperature aging of the battery cell, wherein the battery cell is switched from a normal-temperature aging chamber to a high-temperature aging chamber for high-temperature aging, and the temperature range is as follows: 30-85 ℃, and the time range is as follows: 4 h-12 h; the electric core is arranged on a vibrating device in a high-temperature aging chamber to vibrate, and the vibration frequency range is as follows: 5 Hz-30 Hz, amplitude range: 1.0-3.0 mm, vibration time range: 10 min-30 min, vibration time interval range: 2 h-4 h;

step 3), cell formation, wherein the formation pressurization range is as follows: 0.2 Mpa-0.8 Mpa, and the formation temperature range is as follows: and (3) at 30-85 ℃, after the formation pressure temperature meets the requirement, carrying out gradient gradually-increasing current type charging on the battery cell, and specifically, comprising the following steps:

the first stage is as follows: constant-current charging, wherein the charging is carried out until the reversible capacity is 10% -15%, and the charging current range is as follows: 0.02C-0.05C, charging time: 2.0-7.5 h;

and a second stage: constant-current charging, wherein the charging is carried out until the reversible capacity is 20% -35%, and the charging current range is as follows: 0.05C-0.4C, charging time: 0.5-7.0 h;

and a third stage: constant-current charging, wherein the charging is carried out until the reversible capacity is 30% -50%, and the charging current range is as follows: 0.2C-0.6C, charging time: 0.5-2.5 h.

In step 1) and step 2), the vibration of the battery cell is along the thickness direction of the battery cell.

In the whole aging stage, the temperature error is controlled to be +/-3 ℃, the normal temperature time is controlled to be +/-3 h, the high temperature time is controlled to be +/-2 h, the vibration frequency is controlled to be +/-3 Hz, the amplitude is controlled to be +/-0.5 mm, the vibration time is controlled to be +/-5 min, and the vibration time interval is controlled to be +/-30 min.

In the whole formation stage of the invention, the temperature error is controlled to be +/-3 ℃, and the pressure error is controlled to be +/-0.01 MPa.

The formation temperature of the invention is consistent with the high-temperature aging temperature.

The invention focuses on the optimization of the aging process, increases the high-temperature heating process in the aging process and the vibration process with certain frequency along the thickness direction of the battery core, on one hand, accelerates the diffusion speed of the electrolyte to the interior of the battery core to enable the electrolyte to more uniformly infiltrate the pole pieces, and on the other hand, preheats the battery core to prevent the compact degree of the SEI film formation caused by the nonuniform temperature of the pole pieces at the central part of the battery core when the battery is started to be charged after being high-temperature formed into small current, and influences the consistency and the high-temperature cycle performance of the battery core.

The invention reduces the aging time so as to shorten the production period of the battery, reduces the aging time to 22-50% of the original aging time, and can obviously improve the consistency and the high-temperature cycle performance of the battery.

Drawings

FIG. 1 is a graph comparing the high temperature cycles at 45 ℃ of 1C/1C 100% DOD for examples of the present invention and for a reference example;

fig. 2 is a front view of a cell and a vibration apparatus;

FIG. 3 is a top view of FIG. 2;

fig. 4 is a side view and a schematic diagram of cell aging stage vibration of fig. 2.

Detailed Description

The invention will be further described with reference to specific examples in order to enhance the understanding and appreciation of the invention. It should be noted that the example is provided only for explaining the present invention, so as to facilitate the understanding of the preferred embodiments provided by the skilled person in the art, and not to limit the present invention, the present invention is not limited to the following embodiments, and some modifications and changes to the patent shall fall within the scope of the claims of the patent, i.e. equivalent changes made to the claims of the present invention, and still fall within the scope covered by the present invention.

In fig. 1, curve a of the present invention is a 45 ℃ 1C/1C 100% DOD high temperature cycle curve for a cell produced in example 1 of the present invention; curve B is a 45 ℃ 1C/1C 100% DOD high temperature cycle curve for a cell produced using the prior art as a reference. It can be seen in the figure that after the vibration process and the high-temperature aging process are added in the aging process of the battery cell produced by the embodiment of the invention, the electrolyte can more uniformly and rapidly infiltrate the pole pieces, and the battery cell is preheated by the high-temperature aging, so that the problem that the compactness formed by the SEI film is different due to the uneven temperature of the pole pieces at the central part of the battery cell when the battery cell is changed into a small current at high temperature and starts to be charged is solved, and the high-temperature cycle performance of the battery cell is improved. The high temperature cycle test method is referred to the standard cycle life test method in GBT 31484-2015.

In fig. 2, a battery cell is placed on the vibration device 1, 2 is a battery cell positive tab, 3 is a battery cell negative tab, 4 is a battery cell, and 5 is a battery cell airbag.

In fig. 3, on the vibration device 1, 3 is a cell negative electrode tab, and 4 is a cell.

In fig. 4, the vibration device 1 works, 4 is a battery cell, 5 is a battery cell airbag, and the battery cell 4 vibrates along the thickness direction of the battery cell 4 according to a certain frequency. See the direction of vibration.