Liquid injection anti-spray device for lithium ion battery

Abstract

The application discloses a kind of lithium ion battery liquid injection anti-spray liquid devices, belong to lithium battery technical field, including the liquid injection head of battery liquid injection mouth, liquid injection head is equipped with laser probe, laser probe includes transmitter and receiver, electrolyte buffer chamber and exhaust chamber are equipped in liquid injection head, electrolyte buffer chamber is equipped with for the liquid discharge port of electrolyte into battery liquid injection mouth, liquid discharge port control valve is installed at liquid discharge port, exhaust chamber is equipped with the exhaust port in communication with liquid discharge port, the laser probe is used to generate laser to liquid surface, according to the phase difference of reflected signal and emission signal, the liquid level of current liquid level can be calculated, since liquid injection is completed, the liquid level will drop in the process that electrolyte infiltrates battery cell, by the structure of the present scheme, can make that exhaust port is opened again after liquid level drops to meet requirements, avoids the problem of liquid injection caused by exhaust port and liquid level too close.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of lithium battery, in particular to a lithium ion battery liquid injection anti-spraying device. BACKGROUND

[0002] The production process of lithium battery is complex, and the materials such as pole piece and diaphragm inside the battery cell are affected by storage time, incoming materials and environment, resulting in differences in volume between batches, and further resulting in poor consistency of space filling rate inside the battery cell. The battery cell with large filling rate is prone to cause high liquid level after liquid injection, and further cause liquid injection spraying problem of square aluminum shell battery cell. There are two common liquid injection methods for battery cell, namely, equal pressure injection and differential pressure injection. After liquid injection is completed, the inside of the battery cell is in a micro-positive pressure state. At the moment when the injection nozzle is lifted, the internal pressure of the battery cell is released through the injection hole to restore to atmospheric pressure state. If the distance between the electrolyte liquid level and the surface of the injection hole is too close during the pressure relief process, it is easy to cause liquid spraying after liquid injection of the battery cell or liquid overflow to contaminate the battery cell during subsequent logistics process, affecting the performance, appearance and sealing nail welding yield of the battery cell.

[0003] For example, the "lithium ion battery vacuum liquid injection machine and its lithium ion battery liquid injection head structure" disclosed in the Chinese patent document, with the publication number CN206003880U, the lithium ion battery liquid injection head structure includes a liquid injection head body and a sealing piece sealingly arranged in the liquid outlet of the liquid injection head body. An isolation groove and a liquid injection channel leading to the liquid injection cavity in the liquid injection head body are formed on the sealing piece. When the sealing piece is in contact with the battery upper cover plate, the liquid injection channel communicates the liquid injection cavity with the liquid injection hole on the battery upper cover plate, and the isolation groove covers the rivet on the battery upper cover plate. Therefore, during the process of injecting electrolyte from the liquid injection cavity into the battery, the electrolyte will not leak outside the liquid injection channel, so there will be no large amount of residual on the battery upper cover plate after the liquid injection is completed, avoiding waste. At the same time, it will not enter the isolation groove to contact the rivet and cause corrosion of the rivet, ultimately improving the liquid injection quality and making the liquid injection operation more efficient and simple. However, the deficiency of this patent is that after the liquid injection is completed, if the liquid injection head is directly separated from the battery, liquid spraying may occur due to the high liquid level. SUMMARY

[0004] The present application is to overcome the problem in the prior art that after the liquid injection head of the liquid injection is completed, the pressure in the battery cell is restored, which is prone to cause liquid spraying, resulting in a decrease in electrolyte and affecting the performance, appearance and sealing nail welding yield of the battery cell. A lithium ion battery liquid injection anti-spraying device is disclosed, which can avoid liquid spraying due to large electrolyte filling rate in the battery cell.

[0005] In order to achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows:

[0006] The application discloses a lithium ion battery liquid injection anti-spraying device, which comprises a liquid injection head installed on a battery liquid injection port, a laser probe installed on the liquid injection head, an electrolyte buffer cavity and an exhaust cavity arranged in the liquid injection head, a liquid discharge port arranged in the electrolyte buffer cavity and used for discharging electrolyte into the battery liquid injection port, and a liquid discharge port control valve installed at the liquid discharge port.

[0007] The liquid injection head is used for injecting liquid into a battery cell, the laser probe is used for emitting laser to a liquid surface, the laser is reflected back after contacting the liquid surface, a signal is generated after the laser probe receives the reflected laser, and the current liquid level of the liquid surface can be calculated according to the phase difference between the reflected signal and the emitted signal.

[0008] As preferred, the lithium ion battery liquid injection anti-spraying device further comprises a logic controller connected with the laser probe, the laser emitted by the emitter is received by the receiver to form a liquid level signal, the liquid level difference between the current liquid level and a reference liquid level is calculated according to the phase difference between the liquid level signal and a reference signal after the liquid level signal is filtered and amplified, and then the current liquid level is obtained.

[0009] As preferred, an exhaust control valve is arranged at the exhaust port, the liquid discharge port is closed after liquid injection is completed, the exhaust control valve is in a closed state, and the exhaust control valve is opened after the current liquid level is lower than the reference liquid level.

[0010] As preferred, the pressure regulating valve is in a closed state during liquid injection, the space in the electrolyte buffer cavity and the battery cell is a closed space, the liquid discharge port is located at the bottom of the electrolyte buffer cavity, and the liquid discharge port stops discharging liquid when the liquid at the battery liquid injection port is balanced with the liquid pressure of the liquid discharge port.

[0011] As preferred, a pressure regulating opening is further arranged in the exhaust cavity and communicates with the upper part of the electrolyte buffer cavity, and a pressure regulating valve is arranged at the pressure regulating opening, during the liquid injection process, the pressure regulating valve is in closed state, after the liquid injection is completed, the pressure regulating valve is opened to balance the pressure difference between the liquid injection port and the electrolyte buffer cavity; after the pressure is balanced, the same amount of gas as the liquid injection amount enters the liquid injection head to fill the empty space generated after the liquid is discharged, thereby ensuring that the pressure in the liquid injection head is consistent before and after the liquid injection.

[0012] As preferred, the liquid injection anti-spraying device for lithium ion battery further comprises an electrolyte supplement cavity, an electrolyte supplement opening is arranged in the electrolyte buffer cavity and communicates with the electrolyte supplement cavity, and the liquid outlet control valve comprises a control valve rod, a first sealing part for closing the electrolyte supplement opening is arranged on the control valve rod, and a second sealing part for closing the liquid outlet is arranged on the control valve rod, through the structure, the electrolyte in the electrolyte supplement cavity is supplemented into the electrolyte buffer cavity after each liquid injection is completed, thereby the liquid level in the electrolyte buffer cavity is consistent after each liquid injection, and further the liquid injection amount is the same each time.

[0013] As preferred, a sealing ring is arranged between the liquid injection head and the battery liquid injection port, thereby ensuring the sealing during the liquid injection process.

[0014] Therefore, the present application has the following beneficial effects: (1) the liquid level in the battery cell can be monitored in real time, and the exhaust is started only after the liquid level drops to a certain height, thereby avoiding the liquid spraying due to the high electrolyte filling rate in the cell; (2) the liquid is controlled by the pressure at the liquid injection port, thereby ensuring the accuracy of the liquid injection amount; (3) the pressure in the liquid injection head and the liquid level in the electrolyte buffer cavity are restored after the liquid injection, thereby the liquid injection amount is the same as before; (4) the liquid injection sealing property is good. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 is a structural schematic diagram of embodiment one of the present application.

[0016] Figure 2 is a flow chart of the present application for realizing the liquid discharge control by detecting the liquid level.

[0017] Figure 3 is a structural schematic diagram of embodiment two of the present application.

[0018] In the figure: 1, liquid injection head 2, laser probe 3, electrolyte buffer cavity 4, exhaust cavity 5, liquid outlet 6, exhaust port 7, electrolyte supplement cavity 8, electrolyte supplement opening 9, control valve rod 10, first sealing part 11, second sealing part 12, pressure regulating opening. DETAILED DESCRIPTION

[0019] Embodiment one, as Figure 1-2As shown, a lithium-ion battery liquid injection and spray prevention device includes a liquid injection head 1 installed on the battery liquid injection port, a sealing ring is provided between the liquid injection head and the battery liquid injection port for improving the sealing of the liquid injection, a downward-facing laser probe 2 is installed on the lower side of the liquid injection head, the laser probe includes a transmitter and a receiver, an electrolyte buffer chamber 3 and an exhaust chamber 4 are provided in the liquid injection head, a drain port 5 for discharging electrolyte into the battery liquid injection port is provided in the electrolyte buffer chamber, a drain port control valve is installed at the drain port, an exhaust port 6 connected to the drain port is provided in the exhaust chamber, the laser probe is connected to the logic controller, the laser generated by the transmitter is reflected after reaching the liquid surface, the reflected laser is received by the receiver to form a liquid level signal, the liquid level signal is filtered and amplified, and the liquid level difference between the current liquid level and the reference liquid level is calculated according to the phase difference between the current liquid level and the reference liquid level, thereby obtaining the current liquid level, and an exhaust control valve is provided at the exhaust port.

[0020] When the injection begins, the drain control valve opens and the exhaust control valve closes, and the electrolyte is continuously injected into the battery cell. At the same time, the laser probe continuously detects the current liquid level. When the current liquid level reaches the highest point, the drain control valve closes and the exhaust control valve remains closed. During this process, the electrolyte continuously infiltrates the inside of the battery cell, causing the liquid level to drop. After the liquid level drops to the set value, the exhaust control valve opens, and the positive pressure gas at the injection port is released into the exhaust chamber. After a period of pressure relief, the exhaust control valve is kept open, and the injection head is separated from the injection port to complete the injection.

[0021] Example 2, as Figure 3As shown, a lithium-ion battery liquid injection and spray prevention device, a lithium-ion battery liquid injection and spray prevention device, includes a liquid injection head 1 installed on the battery liquid injection port, a sealing ring is provided between the liquid injection head and the battery liquid injection port to improve the sealing of the liquid injection, a downward-facing laser probe 2 is installed on the lower side of the liquid injection head, the laser probe includes a transmitter and a receiver, an electrolyte replenishing chamber 7, an electrolyte buffer chamber 3 and an exhaust chamber 4 are provided in the liquid injection head, an electrolyte replenishing opening 8 connected to the electrolyte replenishing chamber is provided at the upper end of the electrolyte buffer chamber, a drain port 5 for discharging the electrolyte into the battery liquid injection port is provided at the lower end, a drain port control valve is installed at the drain port, the drain port control valve includes a control valve stem 9, and the control valve stem is provided with a valve for closing A first sealing portion 10 of the electrolyte replenishing opening and a second sealing portion 11 for closing the drain port control the valve stem's stroke including a first sealing position and a second sealing position. An exhaust port 6 connected to the drain port is provided at the lower end of the exhaust chamber, and a pressure regulating opening 12 connected to the upper part of the electrolyte buffer chamber is provided at the upper end. A pressure regulating valve is provided at the pressure regulating opening, and an exhaust control valve is provided at the exhaust port. The laser probe is connected to the logic controller. The laser generated by the transmitter is reflected after reaching the liquid surface. The reflected laser is received by the receiver to form a liquid level signal. After the liquid level signal is filtered and amplified, the liquid level difference between the current liquid level and the reference liquid level is calculated based on the phase difference between the liquid level and the reference signal, thereby obtaining the current liquid level.

[0022] When the injection starts, the control valve stem is in the first sealing position, the first sealing part is located at the electrolyte replenishing opening, the electrolyte replenishing opening is closed, the drain port is opened, the exhaust control valve is closed, and the electrolyte is continuously injected into the battery cell. In this process, since the space in the battery cell is continuously filled, the pressure in the injection port is continuously increasing, and the gas pressure in the upper part of the electrolyte buffer cavity is continuously decreasing; when the liquid discharged from the electrolyte buffer cavity reaches the set value, the electrolyte is no longer discharged, and the liquid level in the battery cell reaches the highest point. At this time, the control valve stem moves downward to the second sealing position, and the second sealing part is located at the drain port, so that the electrolyte replenishing opening is opened. , the drain port is closed, and the exhaust control valve remains closed. During this process, the electrolyte continuously infiltrates the interior of the battery cell, causing the liquid level to drop. After the liquid level drops to the set value, the exhaust control valve opens, and the positive pressure gas at the injection port is used to release pressure into the exhaust chamber and the electrolyte replenishment chamber. Since the volume of liquid discharged from the electrolyte buffer chamber is equal to the volume of gas entering the injection head from the battery cell, after the pressure relief is completed, the liquid level in the electrolyte buffer chamber returns to the same level as before injection, and the pressure at the injection port returns to normal pressure. Then the injection head is separated from the injection port to complete the injection, ensuring that no liquid spraying occurs.

Claims

1. A device for preventing liquid spraying during filling of a lithium-ion battery, characterized in that: The invention comprises a filling head installed on the battery filling port, the filling head is provided with a laser probe, the laser probe comprises a transmitter and a receiver, an electrolyte replenishing chamber, an electrolyte buffer chamber and an exhaust chamber are provided in the filling head, the electrolyte buffer chamber is provided with a discharge port for discharging electrolyte into the battery filling port, a discharge port control valve is installed at the discharge port, an exhaust port connected with the discharge port is provided in the exhaust chamber; an electrolyte replenishing opening connected with the electrolyte replenishing chamber is provided in the electrolyte buffer chamber, the discharge port control valve comprises a control valve stem, a first sealing portion for closing the electrolyte replenishing opening and a second sealing portion for closing the discharge port are provided on the control valve stem; when the first sealing portion is located at the electrolyte replenishing opening, the electrolyte replenishing opening is closed; when the second sealing portion is located at the discharge port, the discharge port is closed.

2. The lithium-ion battery injection and liquid spray prevention device according to claim 1, characterized in that: It also includes a logic controller, which is connected to the laser probe. After the laser generated by the transmitter is received by the receiver, a liquid level signal is formed. After filtering and amplification, the liquid level difference between the current liquid level and the reference liquid level is calculated based on the phase difference between the liquid level signal and the reference signal, and the current liquid level is obtained.

3. The lithium-ion battery injection and liquid spray prevention device according to claim 2, characterized in that: An exhaust control valve is provided at the exhaust port. After the liquid injection is completed, the exhaust port is closed and the exhaust control valve is first in a closed state. When the current liquid level is lower than the reference liquid level, the exhaust control valve is opened.

4. A lithium-ion battery injection and liquid spray prevention device according to claim 3, characterized in that During the filling process, the exhaust control valve is in a closed state, the space inside the electrolyte buffer chamber and the battery cell is a closed space, and the drain port is located at the bottom of the electrolyte buffer chamber. When the pressure difference between the battery filling port and the upper part of the electrolyte buffer chamber is balanced with the hydraulic pressure of the drain port, the drain port will no longer discharge.

5. The lithium-ion battery injection and liquid spray prevention device according to claim 4, characterized in that: The exhaust chamber is also provided with a pressure regulating opening connected to the upper part of the electrolyte buffer chamber. A pressure regulating valve is provided at the pressure regulating opening. During the liquid injection process, the pressure regulating valve is in a closed state. After the battery cell is exhausted, the exhaust control valve is closed again, and the pressure regulating valve is opened to balance the pressure difference between the exhaust chamber and the electrolyte buffer chamber.

6. The lithium-ion battery injection and liquid spray prevention device according to claim 1, characterized in that: A sealing ring is provided between the liquid filling head and the battery liquid filling port.

Images