JPH0845497A - Method and apparatus for introducing electrolyte into the envelope of an electrochemical cell - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a method for putting an electrolyte into an outer casing of an electrochemical cell. The method includes placing at least a partial vacuum in the interior of a first chamber that is disposed on the outer casing of an electrochemical cell and is operably coupled to the outer casing of the electrochemical cell. The pressure inside the chamber also includes the step of applying a partial vacuum. The fluid electrolyte is transferred from the second chamber, which is located above the first chamber and is operably coupled to the first chamber and is maintained at a positive pressure, to the first chamber, and thus outside the battery. Send to the recipient. When a predetermined amount of electrolyte is pumped from the second chamber into the first chamber, the somewhat lower pressure in the first chamber is ruptured and the interior of the first chamber is pressurized, thereby removing the electrolyte from the outside of the battery. Provides additional driving force for rapid movement into the interior.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method of incorporating an electrolyte into the envelope of an electrochemical cell. The invention also relates to a filling device for putting an electrolyte into the envelope of an electrochemical cell.

[0002]

SUMMARY OF THE INVENTION In accordance with a first aspect of the present invention, at least partial decompression of the interior of a first chamber disposed on and operably coupled to an electrochemical cell envelope. And at least partially depressurizing the interior of the battery by placing the cell on the first chamber operably coupled to the first chamber and maintaining a positive pressure. And supplying the liquid electrolyte from the second chamber into the outer casing of the battery according to the first chamber, and the electrolyte supplied from the second chamber into the first chamber has a predetermined volume. The at least partial vacuum in the first chamber is broken and the first chamber is pressurized to provide an additional driving force to rapidly move the electrolyte into the interior of the cell. There is provided a method of including an electrolyte in the envelope of an electrochemical cell, including:

In this way, the supply of electrolyte from the first chamber to the interior of the battery envelope and from the second chamber to the first chamber is assisted by gravity and the envelope and the first chamber. This is done as a result of the pressure differential between the chambers and as a result of the pressure differential between the chambers.

In this method, before supplying the electrolyte from the second chamber to the inside of the first chamber, only the volume of the electrolyte is kept equal to the predetermined volume inside the second chamber, and The method may include allowing only the predetermined volume to be supplied from the second chamber to the first chamber. The volume of electrolyte inside the second chamber can be maintained by moving the electrolyte into the second chamber, confining the volume of electrolyte inside the second chamber, and removing excess electrolyte from the chamber. .
The electrolyte can be confined by holding the electrolyte inside an upright tube or the like. By applying pressure to the bulk reservoir of electrolyte while allowing at least a partial vacuum inside the second chamber to cause the electrolyte to travel from the bulk reservoir along the conduit means to the second chamber.
The transfer of electrolyte to the chamber can be performed. Thus, the combination of the pressurization of the bulk reservoir and the at least partial vacuum inside the second chamber produces the required driving force for carrying the electrolyte along the conduit.

A drive for causing excess electrolyte transfer from the second chamber along the conduit means to the bulk reservoir by applying at least partial vacuum to the bulk reservoir and pressurizing the second chamber. By generating the force, excess electrolyte can be removed from the second chamber.

This method applies, at least in principle, to the inclusion of any fluid electrolyte in the envelope of an electrochemical cell, for example on the basis of molten alkali metal aluminum halide and of the chemical formula MAlHal ₄
It is considered that the present invention is particularly applied to putting a liquid such as an electrolyte, which is solid at room temperature, for example, a molten electrolyte into the outer casing of a battery. In the above formula, M is alkali, Hal
Is a halide. The battery is preferably a rechargeable electrochemical cell. The electrolyte is, in particular, NaAl
It can be Cl ₄ .

Then, the method comprises a bulk reservoir,
It may include conduit means and any other component that heats all other components to keep the electrolyte molten.

According to a second aspect of the invention, the interior of the chamber is at least partially evacuated and is operably connectable to the electrochemical cell for placement on the envelope of the electrochemical cell. And a first chamber constituting the first chamber, and a second chamber communicating with the first chamber and containing a fluid electrolyte, and arranged on the first container. Done, second
A second container adapted to pressurize the first chamber and first valve means for shutting off the second chamber from the first chamber for enclosing the electrolyte in the envelope of the electrochemical cell. A filling device is obtained.

Thus, the first container can be provided with a device allowing the first container to be connected to a vacuum device, for example a suction pump. The lower end of the first container may be provided with a nozzle through which the fluid electrolyte can pass. The nozzle is adapted to hermetically connect the first container to the envelope of the electrochemical cell. The nozzle may have a second valve means for shutting off passage of electrolyte.

The device can include a bulk electrolyte reservoir with a conduit leading from near the interior bottom of the bulk electrolyte reservoir to near the interior bottom of the second chamber. The second container may include a tube projecting upwardly from the bottom of the chamber, the lower end of the tube being closed by the first valve means and the upper end of the tube being open.

The bulk electrolyte reservoir may be adapted to be pressurized, the electrolyte reservoir and the second chamber being a source of compressed inert gas,
For example, it is connected to a compressed nitrogen source. The bulk reservoir can be configured to be evacuated to at least a partial vacuum, and the second container can be configured to be evacuated to at least a partial vacuum. Thus, suitable devices for connecting the bulk reservoir and the second container to a vacuum device such as a suction pump can be provided on the bulk reservoir and the second container. The device can include control means for automatically controlling the at least partial vacuum and pressurization of the bulk reservoir and the second container. Therefore, the bulk reservoir can be pressurized with nitrogen in order to deliver the electrolyte to the measuring tube, during which at least a partial vacuum is created inside the second container. The electrolyte is then delivered along the conduit to the second chamber, and sufficient electrolyte is delivered such that the second chamber fills the second chamber to a level above the upper end of the measuring tube.
Thereafter, the second chamber is pressurized with nitrogen, during which the internal pressure of the bulk reservoir is brought to at least a partial vacuum. Excess electrolyte is then flushed back from the second chamber along the conduit to the bulk reservoir. Thus, the control means may include detection means, eg electrodes, for detecting the level of electrolyte in the second chamber. Therefore, electrodes can be provided. When the electrodes detect that the electrolyte level has risen above the upper end of the measuring tube, an automatic pressurization of the second chamber and at least partial vacuum reduction inside the bulk reservoir takes place. The control means includes a second electrode in the second chamber configured to detect when the electrolyte level has dropped below the upper end of the measuring tube and the automatic electrolyte supply cycle performed by the device has ended. Can be included.

The electrolyte can be a molten salt electrolyte as described below.

[0013]

The present invention will be described below with reference to the diagram of one embodiment of the filling apparatus of the present invention.

In the figures, reference numeral 10 generally indicates a filling device according to the invention.

The filling device 10 comprises a container 12 which constitutes a chamber 14.
including. The nozzle 16 emerges from the bottom of the chamber 14. Nozzle 16
A valve 18 is provided in the valve. The nozzle 16 is self-sealing and can be fluid-tightly connected to the spout 22 of the cell's envelope so that the container 12 is placed over the electrochemical cell's envelope 20. The container 12 is provided with a fitting in the form of a length of conduit 24. The device is operably connected to a vacuum device (not shown) such as a suction pump.

The filling device 10 also includes a second container 26. This second container constitutes a chamber 28 which is arranged above the container 12. The container 26 includes an upright end open measurement tube 30. The lower end of the measuring tube communicates with the chamber 14. A valve 32 is provided at the lower end of the tube 30. A pair of electrodes 34,
36, like the displacement bar 38, projects into the chamber 28.

A fitting 40 is provided on the container 26. The fitting is operably connected to vacuum device 44 by conduit 42. The vacuum device may be a suction pump or the like.

The container 26 also has another fitting 46. The fitting is operably connected to a compressed nitrogen source 50 by conduit 48.

The filling device 10 also includes a bulk electrolyte reservoir 52. Reservoir 52 further includes a fitting 54 connected to vacuum device 44 by conduit 56 and a fitting 58 connected to compressed nitrogen source 50 by conduit 60.

Conduit 62 with a filter 64 attached
Extends from near the bottom of the bulk reservoir 52 to at or near the bottom of the chamber 28.

The bulk storage 52 stores N stored therein.
A heating means (not shown) is provided that is automatically temperature controlled to maintain the aAlCl ₄ in a molten state. Therefore, the heating means maintains the bulk reservoir at about 200 ° C. This temperature is about 1 which is the melting point of NaAlCl ₄ electrolyte.
Higher than 57 ° C.

A large nitrogen source 50 normally supplies a curtain of low positive pressure dry nitrogen to the interior of the bulk reservoir, thereby evacuating air.

The filling device 10 also includes heating means (not shown) for maintaining all the components at an elevated temperature, typically about 200 ° C.

The filling device 10 also includes an electrical controller (not shown) operably connected to the electrodes 36 and 34, the compressed nitrogen source 50 and the vacuum device 44. If desired, the controller can also be operably connected to the valves 18, 32 and the vacuum generator connected to the chamber 14 so that the entire operation of the filling device 10 can be performed automatically. it can. The volume of the electrolyte retained inside the measuring tube 30 is made slightly adjustable by the displacement rod 38.

In use, the internal pressure of the chamber 28 is partially evacuated by the controller. A partial vacuum, together with the low pressure nitrogen film inside the bulk reservoir 52, melted N 2
A driving force is generated to move the aAlCl ₄ from the vessel 52 along the conduit 62 into the chamber 28. Electrode 34 is chamber 2
8 detects the level of electrolyte inside and
, Indicating that the measuring tube 30 is flooded with molten electrolyte, the controller breaks the partial vacuum inside the chamber 28 and causes a low positive pressure nitrogen membrane to enter the chamber 28. , The pressure inside the chamber 28 is restored to near atmospheric pressure. The controller simultaneously depressurizes the interior of the large reservoir 52 to a partial vacuum. This pressure difference is assisted by gravity to force excess electrolyte inside the chamber 28, ie electrolyte not contained in the measuring tube 30, back into the electrolyte reservoir 52, and a measured volume of electrolyte is measured. Allow it to be enclosed in tube 30. The electrode 36 detects when the electrolyte level is below the upper end of the measuring tube 30, so that the controller breaks the partial vacuum applied to the bulk reservoir 52 and allows low positive pressure nitrogen to enter the bulk reservoir 52. Let During their operation, the valve 32 is closed.

The valve 18 is then opened to allow the electrolyte to enter the cell envelope 20, while the chamber 14 is depressurized to at least a partial vacuum. At the same time, the battery jacket 2
The internal pressure of 0 is also reduced to at least a partial vacuum. The battery envelope 20 and chamber 14 are typically evacuated to an absolute pressure of 20-30 hectopascals. It usually takes about 7 seconds.

When the valve 32 is then opened, the molten electrolyte flows from the measuring tube 30 into the chamber 14 and through it into the cell envelope 20. All the electrolyte is discharged from the measuring tube 30, the operation of lowering the inside of the chamber 14 is stopped, and the nitrogen from the chamber 28 raises the internal pressure of the chamber 14 to near atmospheric pressure, thereby causing the electrolyte to cover the battery envelope 20. To help drive inside. Measuring tube 3
The transfer of electrolyte from 0 to the cell envelope 20 typically occurs for about 4 seconds.

The valves 18 and 32 are then closed, the battery casing 20 is disconnected and the above operation is repeated for the subsequent battery casing.

The controller thus uses a pressure sensor, a low pressure sensor and a level detection electrode. A logic device that can use relay logic controllers and programmable logic controllers to operate electromechanical valves can control pressure drop and nitrogen flow and can control the opening and closing of valves 18 and 32. Automatic means, which may include a robot, places the electrolyte-unfilled battery envelope at the filling device and carries out the filled battery envelope to perform unattended full-automatic battery envelope electrolyte filling. be able to.

The filling device 10 is intended to provide a means for accurately and quickly filling an electrolyte composed of a liquid sodium-aluminum-chlorine compound and filling the inside of the casing of a secondary battery. Applicant thinks.

NaAlCl ₄ is usually difficult to manufacture, store and handle. For example, when it comes in contact with moisture such as water vapor in the atmosphere, hydrochloric acid is generated. Hydrochloric acid is Na
Contaminates AlCl ₄ and increases its corrosivity. Furthermore, since NaAlCl ₄ is solid at 157 ° C. or lower, it is necessary to heat it to 157 ° C. or higher in order to make it liquid. The viscosity in the molten state is low, and the specific gravity at 200 ° C. is about 1.7.

Applicants believe that the following benefits may be obtained by using the filling apparatus 10 to fill NaAlCl ₄ . That is, during the operation of placing the electrolyte inside the battery envelope, the electrolyte is always protected from contamination.

There is no risk of contamination of the mechanical pump used to exchange the electrolyte with the bulk reservoir 52.

For safety reasons, the method of using vacuum rather than pressure to deliver the electrolyte is employed, and thus the positive pressure used at various stages by using compressed nitrogen is Much less than vacuum value, typically 40 hectopascals or 4 kPa (g)
Lower.

Due to the reversal of the electrolyte flow inherent to the device during filling of the measuring tube 30, the filter 6 during each cycle.
4 is automatically cleaned.

This filling device automatically and quickly supplies accurately measured amount of electrolyte as a process of manufacturing a secondary battery.

The filling of the electrolyte into the cell envelope is surprisingly very rapid and takes place within a few seconds.
Pre-evacuating the cell envelope and, in combination with the pressure exerted by the membrane of nitrogen applied to chamber 28, results in a quick, complete and accurate introduction of electrolyte into the cell envelope. Is known.

All piping and metal parts of the filling apparatus 10 are preferably constructed of nickel and the joints are constructed of flange and O-ring seals. The applicant believes that this will substantially eliminate corrosion or stress corrosion cracking and the resulting cracking.

[Brief description of drawings]

FIG. 1 is a diagrammatic view of a filling device of the present invention.

[Explanation of symbols]

 14,26 Container 20 Battery envelope 30 Measuring tube 34,36 Electrode 44 Vacuum device 50 Compressed nitrogen source 52 Reservoir

Claims (13)

[Claims] 1. Arranged on the envelope of an electrochemical cell,
Placing a partial vacuum in the interior of the first chamber operably connected to the envelope so that the interior of the envelope of the battery is at least partially vacuum; and arranging above the first chamber. From a second chamber operably connected to the first chamber and maintained under positive pressure,
The step of supplying the liquid electrolyte to the inside of the battery casing according to the first chamber, and the step of supplying the liquid electrolyte to the inside of the first chamber from the second chamber to the inside of the first chamber when a predetermined volume is reached. Disconnecting the at least partial vacuum and pressurizing the first chamber to provide an additional driving force for rapidly moving the electrolyte into the interior of the battery. A method of putting an electrolyte in the cover. 2. An electrolyte of a predetermined volume, wherein only a volume of the electrolyte is maintained equal to the predetermined volume of the second chamber before supplying the electrolyte from the second chamber to the first chamber. The method of claim 1 including the step of ensuring that only the second chamber is supplied to the first chamber. 3. Moving the electrolyte into the second chamber, confining the volume of electrolyte within the second chamber, and removing excess electrolyte from the chamber, thereby reducing the volume of the volume inside the second chamber. The method of claim 2, wherein the electrolyte is maintained. 4. The electrolyte of the second chamber is pressurized by pressurizing the bulk reservoir while at least partially vacuuming the chamber and allowing the electrolyte to travel from the bulk reservoir along the conduit means to the second chamber. The method according to claim 3, wherein the transfer to the second chamber is performed. 5. A driving force for causing excess electrolyte transfer from the second chamber along the conduit means to the bulk reservoir by applying at least a partial vacuum to the bulk reservoir and pressurizing the second chamber. The method of claim 4, wherein excess electrolyte is removed from the second chamber by generating a. 6. A first operably connectable to an electrochemical cell for placement on an outer casing of the electrochemical cell and adapted to at least partially evacuate the interior of the chamber.
Of the first chamber and a second chamber for communicating with the first chamber and containing a fluid electrolyte, the second chamber being disposed on the first container to form the second chamber. A filling device for admitting an electrolyte into an electrochemical cell envelope, comprising a second container adapted to be pressurizable and a first valve means for shutting off the second chamber from the first chamber. 7. The first container comprises a device for allowing the first container to be connected to a vacuum device, and a nozzle at the first lower end through which a fluid electrolyte can pass, the nozzle comprising: A second container adapted to hermetically connect the first container to the envelope of the electrochemical cell and a second for shutting off passage of the electrolyte.
7. The device of claim 6 having the valve means of. 8. A device according to claim 6 or 7, comprising a large electrolyte container, the conduit leading from the interior of the electrolyte container near the bottom of the large electrolyte container to near the bottom of the interior of the second chamber. 9. The second container comprises a tube projecting upwardly from the bottom of the chamber, the lower end of the tube being closed by the first valve means and the upper end of the tube being open. The device according to. 10. The apparatus of claim 9, wherein the bulk electrolyte reservoir is adapted to be pressurized and the electrolyte reservoir and second chamber are connected to a source of compressed inert gas. 11. The bulk reservoir is evacuable to a vacuum, the second container is also evacuable to at least a partial vacuum, and the bulk reservoir and the second container are the bulk reservoir and the second container. A device according to claim 9 or 10, comprising a suitable device for connecting to a vacuum device. 12. A control means for automatically controlling the decompression of the at least partial vacuum and the pressurization of the bulk reservoir and the second container, the control means comprising the level of electrolyte in the second chamber. An apparatus according to claim 11, including detection means for detecting. 13. A first electrode in the second chamber for detecting when the electrolyte level rises above the upper end of the measuring tube, and the detecting means has an upper end of the measuring tube with the electrolyte level. 13. A device according to claim 12 including a second electrode inside the second chamber for detecting when it has descended further down.