Simple square lithium battery negative pressure formation device

Abstract

The utility model relates to the technical field of square lithium batteries, and discloses a simple square lithium battery negative pressure formation device which comprises a vacuum pump and a vacuum drying oven, a battery rack comprises side plates, a bottom frame is arranged between the side plates, an air guide shell is arranged on one side of each side plate, a ventilation groove is formed in the position, located in the middle of the air guide shell, of the interior of each side plate, and the bottom frame is arranged in the ventilation groove. A fan is arranged on one side of the top of the vacuum drying oven, a liquid collecting bottle is arranged on one side of the top of the sliding plate, a square lithium battery is arranged between the air guide shells, and a liquid collecting pipe is arranged between the top of the square lithium battery and the liquid collecting bottle. The performances such as internal resistance and cycle life of the battery are optimized; in addition, the whole device is simple in structure and easy to implement due to the fact that excessive design is not needed in appearance, and the square battery formation device can be obtained by an enterprise in a low-cost and fast aging mode.

Description

Technical Field

[0001] The utility model relates to the technical field of square lithium batteries, in particular to a simple square lithium battery negative pressure formation device. Background Art

[0002] After the battery is filled, the electrode material is not in the best applicable state, and the formation process is required to charge and activate the battery. During the formation, a solid electrolyte interface film (SEI) is formed on the surface of the negative electrode. The quality of the SEI film directly affects the electrochemical properties of the battery, such as cycle life, stability, self-discharge, and safety, and meets the requirements of secondary battery sealing and maintenance-free. Generally speaking, the higher the formation temperature, the lower the viscosity of the electrolyte, the higher the conductivity of the electrolyte, and the faster the diffusion rate of the electrode material ions. Therefore, the smaller the polarization, the better the formation effect.

[0003] However, during the lithium battery formation process, gas will be generated inside the battery, causing the internal pressure of the battery to increase. If the gas cannot be discharged in time, it may cause the shell to swell or even be damaged. If the gas remains inside the battery for a long time, it will affect the quality of the SEI film formation, and will also cause air pockets between the pole piece and the diaphragm, hindering the transmission of lithium ions, affecting the internal resistance and other performance of the battery. At present, the common solution for square lithium batteries is open formation, leaving a small hole at the top of the battery to discharge the gas inside the battery through the pressure difference between the inside and outside of the battery. This natural exhaust method may not be completely exhausted, and some gas will remain inside the battery, causing adverse effects. At the same time, during the open formation, moisture in the environment will also enter the battery and react with the electrolyte, affecting the quality of the SEI film, thereby directly affecting the electrical performance of the battery. In view of this, square batteries generally use the method of breaking the vacuum by negative pressure formation of inert gas, which not only solves the problem of poor exhaust, but also prevents moisture from entering the battery.

[0004] In the prior art (Patent Publication No. CN217522106U), a negative pressure battery formation device is provided, which can effectively extract the gas generated during the battery formation process. However, the device does not have a heating function, and low-temperature or room-temperature formation will increase battery polarization, prolong battery formation time, and reduce battery SEI film quality and formation efficiency. Utility Model Content

[0005] The purpose of the utility model is to provide a simple square lithium battery negative pressure formation device to solve the problems raised in the above background technology.

[0006] To achieve the above-mentioned purpose, the utility model provides the following technical solutions: a simple square lithium battery negative pressure formation device, comprising a vacuum pump and a vacuum oven, wherein slide rails are provided on both sides of the bottom inner wall of the vacuum oven, a slide plate is provided on the top of the slide rail, a battery rack is provided above the slide plate, the battery rack comprises side panels, a bottom frame is provided between the side panels, an air guide shell is provided on one side of the side panel, a ventilation slot is provided inside the side panel in the middle of the air guide shell, a fan is provided on one side of the top of the vacuum oven, a liquid collecting bottle is provided on one side of the top of the slide plate, square lithium batteries are provided between the air guide shells, and a liquid collecting pipe is provided between the top of the square lithium battery and the liquid collecting bottle.

[0007] Furthermore, a vacuum exhaust hole is provided on one side of the vacuum oven, and a vacuum gauge, a temperature digital display and a vacuum valve are also provided on one side of the vacuum oven. One end of the vacuum valve is connected to an air pipe, and one end of the air pipe is provided with a vacuum pump.

[0008] Furthermore, a buffer tank is provided at one end of the vacuum pump, one end of the buffer tank is connected to one end of the air pipe, a three-way valve is provided on the side of the air pipe close to the vacuum valve, and one end of the three-way valve is used to connect to a nitrogen bottle.

[0009] Furthermore, a through groove is formed at the bottom of the side plate below the bottom frame.

[0010] Furthermore, there are a plurality of air guide shells, and the plurality of air guide shells are arranged at equal intervals on the side panel.

[0011] Furthermore, a through strip groove is provided in the middle of the air guide shell, and the strip groove is connected with the ventilation groove on the side panel.

[0012] Compared with the prior art, the beneficial effects of the utility model are:

[0013] The utility model realizes that when the lithium battery is formed, the square lithium battery to be formed is placed between the air guide shells of the battery rack, and then the entire battery rack together with the square lithium battery is placed on the slide, and the slide is pushed into the vacuum oven, and heated by the heating rod in the vacuum oven. During the heating process, air is blown downward by the fan, and the temperature in the box is kept balanced by the cooperation of the air guide shell and the ventilation slot, and the circulating hot air is blown to the outside of the square lithium battery through the air guide shell, which helps to evenly distribute the temperature around the square lithium battery. The appropriate temperature cooperates with the formation method of exhaust negative pressure to make the battery activation efficiency higher and the SEI film formation quality better, thereby optimizing the internal resistance of the battery, the cycle life and other performances; in addition, the entire device does not need to invest too much design due to its appearance, has a simple structure, is easy to implement, and can help enterprises obtain square battery formation devices at a lower cost and in a faster time. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1This is a three-dimensional diagram of a simple square lithium battery negative pressure formation device of the utility model;

[0015] Figure 2 This is a schematic diagram of the internal structure of a simple square lithium battery negative pressure formation device of the utility model;

[0016] Figure 3 This is a schematic diagram of the side plate connection structure of a simple square lithium battery negative pressure formation device of the utility model;

[0017] Figure 4 for Figure 3 Enlarged structural diagram at A in the middle.

[0018] In the figure: 1. vacuum pump; 2. buffer tank; 3. air pipe; 4. three-way valve; 5. exhaust hole of vacuum box; 6. vacuum gauge; 7. digital temperature display; 8. vacuum valve; 9. vacuum oven; 10. slide rail; 11. slide plate; 12. side panel; 13. bottom frame; 14. air guide shell; 15. square lithium battery; 16. liquid collecting pipe; 17. liquid collecting bottle; 18. fan. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments.

[0020] See also Figure 1-Figure 4 The utility model provides a technical solution: a simple square lithium battery negative pressure formation device, including a vacuum pump 1 and a vacuum oven 9, slide rails 10 are arranged on both sides of the inner wall of the bottom of the vacuum oven 9, a slide plate 11 is arranged on the top of the slide rail 10, and a battery rack is arranged above the slide plate 11, the battery rack includes a side plate 12, a bottom frame 13 is arranged between the side plates 12, a wind guide shell 14 is arranged on one side of the side plate 12, and a ventilation slot is opened in the middle of the wind guide shell 14 inside the side plate 12, a fan 18 is arranged on one side of the top of the vacuum oven 9, a liquid collecting bottle 17 is arranged on one side of the top of the slide plate 11, a square lithium battery 15 is arranged between the wind guide shell 14, and a liquid collecting pipe 16 is arranged between the top of the square lithium battery 15 and the liquid collecting bottle 17. The appropriate temperature and the vacuum negative pressure formation method make the battery activation efficiency higher and the SEI film formation quality better, thereby optimizing the internal resistance, cycle life and other performances of the battery; in addition, the entire device does not need to invest too much design in appearance, the structure is simple, and it is easy to implement, which can help enterprises obtain square battery formation devices at a lower cost and faster time.

[0021] A vacuum exhaust hole 5 is provided on one side of the vacuum oven 9. A vacuum gauge 6, a temperature digital display gauge 7 and a vacuum valve 8 are also provided on one side of the vacuum oven 9. One end of the vacuum valve 8 is connected to an air pipe 3, and one end of the air pipe 3 is provided with a vacuum pump 1. A buffer tank 2 is provided at one end of the vacuum pump 1, and one end of the buffer tank 2 is connected to one end of the air pipe 3. A three-way valve 4 is provided on one side of the air pipe 3 close to the vacuum valve 8, and one end of the three-way valve 4 is used to connect a nitrogen bottle. During operation, the sealed door of the vacuum oven 9 is opened, and the semi-finished square lithium battery 15 with liquid injection is placed between the air guide shells 14 of the battery rack, and then the entire battery rack together with the square lithium battery is placed on the slide 11, and the slide 11 is pushed into the vacuum oven 9. After connecting the test line, the battery injection hole is connected to the liquid collecting pipe 16, and the electrolyte is introduced into the electrolyte collection bottle 16; then the oven door is closed, and the temperature in the vacuum oven 9 is controlled at 35℃~45℃ through the heating mechanism and the temperature digital display 7, and the fan 18 is started. It is left to stand for a period of time to allow the temperature inside and outside of the battery to reach a balance. After the formation begins, the entire process ensures that the ambient temperature is within the range of 35℃~45℃. Then the vacuum pump 1 works to evacuate the interior through the exhaust valve, and by closing the connection end of the three-way valve 4 and the nitrogen bottle, a buffer tank 2 is set, so that the exhaust mechanism can control the internal pressure of the box through the exhaust speed, and the internal pressure is controlled within the range of -10kPa-70kPa. The pressure inside the box is observed by the vacuum gauge 6. During the formation process, the pressure inside the box is adjusted according to the different gas production of the battery in the formation stage. After charging for a certain period of time, the negative pressure is reduced, and the electrolyte is prevented from being taken out too much by using stepped pressure control. After the formation charging is completed, the vacuum device is turned off, and the three-way valve 4 of the gas supply device is connected to the nitrogen bottle to deliver nitrogen into the cavity to break the vacuum. This high temperature and negative pressure formation method can solve the problem of insufficient exhaust, make the formed SEI film more consistent, and make the battery activation efficiency higher.

[0022] A through slot is provided at the bottom of the side plate 12 below the bottom frame 13 for air to circulate from the bottom of the bottom frame 13 , thereby improving the uniformity of the temperature inside the vacuum oven 9 .

[0023] There are a plurality of air guide shells 14, which are arranged equidistantly on the side plate 12. This facilitates placing a plurality of square lithium batteries 15 on the battery rack at the same time, thereby improving the efficiency of battery formation.

[0024] A through strip groove is provided in the middle of the air guide shell 14, and the strip groove is connected with the ventilation groove on the side plate 12. The fan 18 blows air downward, and the temperature inside the box is kept balanced through the cooperation of the air guide shell 14 and the ventilation groove. The circulating hot air is blown to the outside of the square lithium battery 15 through the air guide shell 14, which helps to evenly distribute the temperature around the square lithium battery 15.

[0025] When the lithium battery is formed, the square lithium battery to be formed is placed between the air guide shells 14 of the battery rack, and then the entire battery rack together with the square lithium battery is placed on the slide 11, and the slide 11 is pushed into the vacuum oven 9, and heated by the heating rod in the vacuum oven 9. During the heating process, the fan 18 blows air downward, and the temperature in the box is kept balanced by the cooperation of the air guide shell 14 and the ventilation slot. The circulating hot air is blown to the outside of the square lithium battery 15 through the air guide shell 14, which helps to evenly distribute the temperature around the square lithium battery 15. The appropriate temperature combined with the vacuum negative pressure formation method makes the battery activation efficiency higher and the SEI film formation quality better, thereby optimizing the battery's internal resistance, cycle life and other performance; in addition, the entire device does not need to invest too much design due to its appearance, has a simple structure, is easy to implement, and can help enterprises obtain square battery formation devices at a lower cost and faster time.

[0026] Based on the embodiments of the present utility model, all other embodiments obtained by ordinary technicians in the field without making any creative work shall fall within the scope of protection of the present utility model.

Claims

1. A simple square lithium battery negative pressure formation device, comprising a vacuum pump (1) and a vacuum oven (9), characterized in that: Slide rails (10) are provided on both sides of the inner wall at the bottom of the vacuum drying oven (9), a slide plate (11) is provided on the top of the slide rails (10), a battery rack is provided above the slide plate (11), the battery rack comprises side plates (12), a bottom frame (13) is provided between the side plates (12), an air guide shell (14) is provided on one side of the side plates (12), a ventilation slot is provided inside the side plates (12) in the middle of the air guide shell (14), a fan (18) is provided on one side of the top of the vacuum drying oven (9), a liquid collecting bottle (17) is provided on one side of the top of the slide plate (11), a square lithium battery (15) is provided between the air guide shells (14), and a liquid collecting pipe (16) is provided between the top of the square lithium battery (15) and the liquid collecting bottle (17).

2. A simple square lithium battery negative pressure formation device according to claim 1, characterized in that: A vacuum exhaust hole (5) is provided on one side of the vacuum oven (9), and a vacuum gauge (6), a temperature digital display gauge (7) and a vacuum valve (8) are also provided on one side of the vacuum oven (9). One end of the vacuum valve (8) is connected to an air pipe (3), and one end of the air pipe (3) is provided with a vacuum pump (1).

3. A simple square lithium battery negative pressure formation device according to claim 2, characterized in that: A buffer tank (2) is provided at one end of the vacuum pump (1), one end of the buffer tank (2) is connected to one end of an air pipe (3), a three-way valve (4) is provided on the side of the air pipe (3) close to the vacuum valve (8), and one end of the three-way valve (4) is used to connect to a nitrogen bottle.

4. A simple square lithium battery negative pressure formation device according to claim 1, characterized in that: The bottom of the side plate (12) is provided with a through slot below the bottom frame (13).

5. A simple square lithium battery negative pressure formation device according to claim 1, characterized in that: There are a plurality of air guide shells (14), and the plurality of air guide shells (14) are arranged at equal intervals on the side plate (12).

6. A simple square lithium battery negative pressure formation device according to claim 5, characterized in that: A through strip groove is provided in the middle of the air guide shell (14), and the strip groove is connected to the ventilation groove on the side plate (12).

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