KR20240047856A - Method for manufacturing cell - Google Patents

Abstract

The present invention relates to a cell manufacturing method that prevents insufficient or excessive injection of electrolyte into the pouch and improves the impregnability of the electrolyte, thereby producing a pouch cell of improved quality.
The cell manufacturing method for manufacturing a pouch cell according to the present invention includes the steps of measuring the physical quantity of the electrode assembly accommodated inside the pouch, determining the amount of electrolyte to be injected into the pouch based on the physical quantity of the electrode assembly, and the determined It may include the step of injecting an electrolyte equivalent to the amount of the injected liquid into the pouch containing the electrode assembly.

Description

Cell manufacturing method {METHOD FOR MANUFACTURING CELL}

The present invention relates to a cell manufacturing method, and more specifically to a cell manufacturing method for manufacturing secondary battery cells.

In recent years, the price of energy sources has risen due to the depletion of fossil fuels, and interest in environmental pollution has increased, and the demand for eco-friendly alternative energy sources has become an essential factor for future life. Accordingly, research continues on various power production technologies such as solar power, wind power, and tidal power, and there is also great interest in power storage devices such as batteries to use the electric energy produced in this way more efficiently.

Moreover, as technology development and demand for electronic mobile devices and electric vehicles using batteries increase, the demand for batteries as an energy source is rapidly increasing, and accordingly, much research is being conducted on batteries that can meet various needs. there is.

Batteries that store electrical energy can generally be divided into primary batteries and secondary batteries. Primary batteries are disposable consumable batteries, while secondary batteries are rechargeable batteries manufactured using materials in which oxidation and reduction processes between current and materials can be repeated. In other words, when a reduction reaction is performed on a material by current, the power is charged, and when an oxidation reaction is performed on the material, the power is discharged. As this charging and discharging is repeatedly performed, electricity is generated.

Secondary batteries can be classified according to their shape into cylindrical cells, pouch cells, and prismatic cells. Among them, the pouch cell may include a process of injecting an electrolyte into the pouch and a process of removing gas generated inside the pouch.

In the past, there were cases where the amount of electrolyte injected into the pouch was insufficient or excessive. Accordingly, problems such as insufficient impregnation of the electrode assembly or an increase in the thickness of the pouch occurred.

Therefore, in order to solve this problem, there is a need for a cell manufacturing method that can prevent insufficient or excessive injection of electrolyte into the pouch.

The object of the present invention is to provide a cell manufacturing method that prevents insufficient or excessive injection of electrolyte into the pouch and improves the impregnability of the electrolyte, thereby producing a pouch cell of improved quality.

The cell manufacturing method for manufacturing a pouch cell according to the present invention includes the steps of measuring the physical quantity of the electrode assembly accommodated inside the pouch, determining the amount of electrolyte to be injected into the pouch based on the physical quantity of the electrode assembly, and the determined It may include the step of injecting an electrolyte equivalent to the amount of the injected liquid into the pouch containing the electrode assembly.

In the step of determining the amount of electrolyte to be injected, the volume of pores formed in the electrode assembly may be determined according to the physical quantity of the electrode assembly.

In the step of determining the amount of electrolyte to be injected, the amount to be injected may be determined according to the volume of pores formed in the electrode assembly.

In the step of determining the amount of electrolyte to be injected, if the value measuring the volume occupied by the electrode active material of the electrode assembly is A, and the value obtained by multiplying the weight of the electrode active material used and the density of the electrode active material is B, the value is calculated by subtracting B from A. can be calculated as the volume of pores formed in the electrode assembly.

In the step of determining the amount of electrolyte to be injected, the amount to be injected may be calculated by subtracting B from A and multiplying the correction value determined according to the type of electrode assembly.

The cell manufacturing method may further include a degassing step of removing gas inside the pouch after injecting the electrolyte.

The degassing step may include initial degassing to first remove the gas inside the pouch, and additional degassing to additionally remove the gas inside the pouch after checking the state of the pouch on which the initial degassing is completed.

In the additional degassing step, the electrolyte solution overfilled inside the pouch may be discharged.

The degassing step may further include an electrolyte replenishment step of replenishing the insufficient electrolyte solution inside the pouch on which initial degassing has been completed.

Additional degassing steps may be carried out multiple times.

The degassing step is preceded by multiple additional degassings, and may further include an additional electrolyte replenishment step to replenish the insufficient electrolyte solution inside the pouch.

The pouch cell according to the present invention can be manufactured by one of the cell manufacturing methods described above.

The cell manufacturing method for manufacturing a pouch cell according to the present invention includes the steps of measuring the physical quantity of the electrode assembly accommodated inside the pouch, determining the amount of electrolyte to be injected into the pouch based on the physical quantity of the electrode assembly, and the determined It may include the step of injecting an electrolyte equivalent to the amount of the injected liquid into the pouch containing the electrode assembly.

Accordingly, it is possible to provide a cell manufacturing method that prevents insufficient or excessive injection of electrolyte inside the pouch and improves the impregnability of the electrolyte, thereby producing a pouch cell of improved quality.

The effects according to the present invention are not limited to the contents exemplified above, and further various effects are included in the present specification.

1 is a flow chart schematically showing a cell manufacturing method according to an embodiment of the present invention.
Figure 2 is a schematic diagram showing an electrolyte being injected into a pouch in a cell manufacturing method according to an embodiment of the present invention.
Figure 3 is a schematic diagram showing a sealed pouch in the cell manufacturing method according to an embodiment of the present invention.
Figure 4 is a schematic diagram showing a pouch in which a degassing hole is formed in the degassing step of the cell manufacturing method according to an embodiment of the present invention.

Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention will be described in detail so that those skilled in the art can easily implement the present invention. However, the present invention may be implemented in various different forms and is not limited or restricted by the following examples.

In order to clearly explain the present invention, detailed descriptions of parts unrelated to the description or related known technologies that may unnecessarily obscure the gist of the present invention have been omitted, and reference signs are added to components in each drawing in this specification. In this regard, identical or similar reference numerals are assigned to identical or similar components throughout the specification.

In addition, terms or words used in this specification and claims should not be construed as limited to their usual or dictionary meanings, and the inventor may appropriately define the concept of terms in order to explain his or her invention in the best way. It must be interpreted with meaning and concept consistent with the technical idea of the present invention based on the principle that it can be done.

1 is a flowchart schematically showing a cell manufacturing method according to an embodiment of the present invention.

The present invention provides a cell manufacturing method as an example.

The cell manufacturing method according to an embodiment of the present invention may be a method of manufacturing a secondary battery. At this time, the secondary battery may refer to a pouch cell. Therefore, the cell manufacturing method according to an embodiment of the present invention may be a method of manufacturing a pouch cell.

The pouch cell manufacturing process may include inserting an electrode assembly into the pouch 100 and then injecting an electrolyte solution into the pouch 100. Here, the pouch 100 is a part that forms the outer shape of the pouch cell and may include a metal layer, a sealant layer, etc. Additionally, the electrode assembly may have a form in which an anode, a cathode, and a separator are stacked.

Referring to FIG. 1, which is carried out before injecting the electrolyte into the inside of the pouch 100, the cell manufacturing method according to an embodiment of the present invention includes measuring the physical quantity of the electrode assembly accommodated inside the pouch 100. (S10) may be included.

The step of measuring the physical quantity of the electrode assembly (S10) can measure the physical quantity necessary to determine the appropriate amount of electrolyte solution used to manufacture the pouch cell. In the step (S10) of measuring the physical quantity of the electrode assembly according to an embodiment of the present invention, the thickness of the electrode, the thickness of the foil, the area per electrode, and the number of electrode layers may be measured. Here, the electrode can be a cathode or an anode.

It is carried out after the physical quantity of the electrode assembly is measured, and the cell manufacturing method according to an embodiment of the present invention includes determining the amount of electrolyte to be injected into the inside of the pouch 100 based on the measured physical quantity of the electrode assembly. (S20) may be included.

The electrode active material may be applied to both sides of the foil of the electrode. Therefore, there may be a difference between the volume of the electrode active material used in the pouch cell manufacturing process and the volume occupied by the electrode active material when applied to the actual electrode foil. The difference in volume between these two can be roughly viewed as pores formed in the electrode assembly. In the present invention, when these two volume differences are referred to as pores formed in the electrode assembly, in the cell manufacturing method according to an embodiment of the present invention, the amount of electrolyte to be injected into the pouch 100 is calculated based on the pores formed in the electrode assembly. can do. Therefore, the pouch cell manufactured by the cell manufacturing method according to an embodiment of the present invention calculates the amount of electrolyte injected based on the space formed inside the pouch 100, so that insufficient electrolyte is injected into the pouch 100. The degree of excessive injection may be reduced.

In the step (S20) of determining the amount of electrolyte to be injected into the inside of the pouch 100, the volume of the pores formed in the electrode assembly is determined according to the measured physical quantity of the electrode assembly, and the volume of the pores formed in the electrode assembly is determined. The liquid amount can be determined. To explain this in more detail, if the value measuring the volume occupied by the electrode active material of the electrode assembly is A, and the value obtained by multiplying the weight of the electrode active material used and the density of the electrode active material is B, then the value obtained by subtracting B from A is It can be calculated as the volume of pores formed in the electrode assembly. Additionally, the amount of liquid to be injected can be calculated by multiplying the value obtained by subtracting B from A by a correction value determined depending on the type of electrode assembly.

In the step of measuring the physical quantity of the electrode assembly (S10), the volume occupied by the electrode active material of the electrode assembly can be calculated through the measured physical quantity. By subtracting the thickness of the foil from the electrode thickness, the thickness of the electrode active material applied to the foil can be obtained. By multiplying the thickness of the electrode active material obtained in this way by the area per electrode, the volume of the electrode active material contained in one electrode can be obtained. By multiplying this value by the number of electrode layers included in the electrode assembly, the volume occupied by the electrode active material of the electrode assembly can be calculated. This value can be A as described above.

By measuring the weight of the electrode active material used in the manufacture of the electrode assembly and multiplying the measured weight by the density of the electrode active material, the volume that the electrode active material occupies in the electrode assembly can theoretically be calculated. This value can be the B described above.

If you calculate the values of A and B previously, you can get the value by subtracting B from A. This value can be calculated as the volume of pores formed in the electrode assembly.

Once the volume of the pores formed in the electrode assembly is calculated, the amount of liquid to be injected can be calculated by multiplying this value by a correction value determined depending on the type of electrode assembly.

Figure 2 is a schematic diagram showing the electrolyte being injected into the pouch 100 in the cell manufacturing method according to an embodiment of the present invention, and Figure 3 is a schematic diagram showing the pouch 100 in the cell manufacturing method according to an embodiment of the present invention. ) is a schematic diagram showing the sealed state.

The cell manufacturing method according to an embodiment of the present invention is to determine the amount of electrolyte to be injected into the inside of the pouch 100 based on the physical quantity of the electrode assembly, and then inject the electrode assembly into the pouch 100 as much as the determined amount. The step of injecting the electrolyte (S30) may proceed.

In the step (S30) of injecting the electrolyte into the pouch 100 containing the electrode assembly, the electrolyte necessary for the pouch cell to generate electrical energy may be added. The electrolyte solution can serve as a medium that helps ions move between electrodes, and may contain salts, solvents, additives, etc. Referring to FIG. 2, an electrolyte injection device 200 may be used to inject an electrolyte into the pouch 100.

Referring to FIG. 3, the pouch 100 into which the electrolyte solution has been injected may be sealed by a sealing portion 300 formed at one end. The pouch 100 with the sealing portion 300 sealed may undergo an activation process.

The activation process may include aging and charge/discharge. Here, aging may refer to the process of storing the electrolyte injected into the pouch 100 at room temperature for a certain period of time so that it can well permeate the anode and cathode. After the electrolyte has sufficiently penetrated the electrode through the aging process, part of it can be charged and discharged.

Figure 4 is a schematic diagram showing the pouch 100 in which the degassing hole 400 is formed in the degassing step of the cell manufacturing method according to an embodiment of the present invention.

Gas may be generated inside the pouch 100 as it undergoes an activation process. Therefore, the cell manufacturing method according to an embodiment of the present invention may further include a degassing step (S40) of removing the gas inside the pouch 100 after injecting the electrolyte solution.

Referring to FIG. 4, a degassing hole 400 may be perforated in the pouch 100 to remove gas inside the pouch 100. A degassing device (not shown) can remove gas inside the pouch 100 through the degassing hole 400.

The degassing step (S40) according to an embodiment of the present invention is an initial degassing (S41) to remove the gas inside the pouch 100 for the first time and an initial degassing (S41) inside the pouch 100 on which the initial degassing (S41) is completed. After checking the condition, additional degassing (S43) to remove the gas inside the pouch 100 may be included. That is, in the degassing step (S40), the process of removing the gas inside the pouch 100 may be carried out in two steps.

Conventionally, the electrolyte solution was injected into the pouch 100, and after the activation process was completed, the gas inside the pouch 100 was collectively removed through degassing. However, in the degassing step (S40) according to an embodiment of the present invention, the gas inside the pouch 100 is first removed through the initial degassing (S41), and the state of the pouch 100 is checked. After this progresses, the gas inside the pouch 100 may be additionally removed through additional degassing (S43). Here, the condition of the pouch 100 can be checked by measuring weight, etc.

As a result of checking the condition of the pouch 100 in which the initial degassing (S41) has been performed, if the electrolyte contained within the pouch 100 is insufficient, the electrolyte replenishment step may proceed. That is, the degassing step (S40) of the cell manufacturing method according to an embodiment of the present invention may further include an electrolyte replenishment step (S42) of replenishing the insufficient electrolyte solution inside the pouch 100 on which initial degassing has been completed. there is. For example, if the weight of the pouch 100 is measured to be less than the predicted weight by a certain amount, there may be a need to replenish the electrolyte inside the pouch 100.

The degassing step (S40) of the cell manufacturing method according to an exemplary embodiment of the present invention includes an electrolyte replenishment step (S42), which can reduce or prevent defects caused by insufficient electrolyte solution in the pouch cell.

Additional degassing (S43) according to an embodiment of the present invention may be performed multiple times. In addition, the degassing step (S40) of the cell manufacturing method according to an embodiment of the present invention is preceded by a plurality of additional degassing (S43), and an additional electrolyte replenishment step to replenish the insufficient electrolyte solution inside the pouch 100. (S44) may be further included. That is, after checking the condition of the pouch 100 and replenishing the insufficient electrolyte, the process of removing the gas inside the pouch 100 may be performed several times.

Therefore, the cell manufacturing method according to an embodiment of the present invention can minimize the degree to which the electrolyte solution in the pouch cell is insufficient and the degree to which the electrolyte solution in the pouch cell is insufficient.

In the additional degassing step of the cell manufacturing method according to another embodiment of the present invention, the electrolyte solution overly injected into the pouch 100 may be discharged.

As a result of checking the condition of the pouch 100 on which the initial degassing (S41) was performed, there may be a case where the electrolyte solution is excessively contained inside the pouch 100. In this case, a process of removing the electrolyte inside the pouch 100 may be necessary.

If excessive electrolyte is injected into the pouch 100, the thickness of the pouch 100 may increase. Additionally, defects such as protruding parts may occur in the outer shape of the pouch cell. Therefore, overfilled pouch cells may have external problems such as thicker thickness and protruding parts compared to good quality pouch cells, which may cause defects in the process of manufacturing modules or packs or reduce the performance of the pouch cells. There is a risk that it may decrease. To solve this problem, in the additional degassing step of the cell manufacturing method according to another embodiment of the present invention, the electrolyte solution overly injected into the pouch 100 may be discharged.

As an example of a method in which the gas is removed from the inside of the pouch 100 in the additional degassing step, a method in which the gas is discharged into the electrolyte solution together with the gas by a degassing device may be possible. It is sufficient to remove the electrolyte inside the pouch 100, and the method by which the electrolyte is removed may vary.

In the pouch cell manufactured by the cell manufacturing method according to the embodiments of the present invention, defects that occur when the electrode assembly is not sufficiently impregnated with the electrolyte due to a lack of electrolyte inside the pouch 100 can be prevented. In addition, the pouch cell manufactured by the cell manufacturing method according to the embodiments of the present invention can prevent defects such as increased thickness and protruding appearance caused by excessive electrolyte solution inside the pouch 100.

Although the present invention has been described above with limited examples and drawings, the present invention is not limited thereto, and the technical idea of the present invention and the following description will be provided by those skilled in the art in the technical field to which the present invention pertains. Various implementations are possible within the scope of equivalence of the claims.

S10: Step of measuring the physical quantity of the electrode assembly
S20: Step of determining the amount of electrolyte to be injected
S30: Step of injecting electrolyte
S40: Degassing step
S41: Initial Degassing
S42: Electrolyte replenishment step
S43: Additional degassing
S44: Additional electrolyte replenishment steps
100: Pouch
200: Electrolyte injection device
300: Sealing part
400: Degassing hole

Claims (12)

In the cell manufacturing method for manufacturing a pouch cell,
Measuring the physical quantity of the electrode assembly accommodated inside the pouch;
Determining the amount of electrolyte to be injected into the pouch based on the physical quantity of the electrode assembly; and
A cell manufacturing method comprising the step of injecting an electrolyte solution into the pouch containing the electrode assembly by a determined injection amount. According to claim 1,
The step of determining the amount of electrolyte to be injected is,
A cell manufacturing method in which the volume of pores formed in the electrode assembly is determined according to the physical quantity of the electrode assembly. According to claim 2,
The step of determining the amount of electrolyte to be injected is,
A cell manufacturing method in which the amount of liquid injected is determined depending on the volume of pores formed in the electrode assembly. According to claim 1,
The step of determining the amount of electrolyte to be injected is,
If the value measuring the volume occupied by the electrode active material of the electrode assembly is A, and the value obtained by multiplying the weight of the electrode active material used and the density of the electrode active material is B, then the value obtained by subtracting B from A is the pore formed in the electrode assembly. Cell manufacturing method calculated by volume. According to claim 4,
The step of determining the amount of electrolyte to be injected is,
A cell manufacturing method in which the injection amount is calculated by subtracting B from A and multiplying the correction value determined depending on the type of electrode assembly. According to claim 1,
A cell manufacturing method further comprising a degassing step of removing gas inside the pouch after injecting the electrolyte solution. According to claim 6,
The degassing step is,
Initial degassing to first remove gas inside the pouch; and
A cell manufacturing method comprising additional degassing to remove gas inside the pouch after checking the condition of the pouch on which initial degassing has been completed. According to claim 7,
The additional degassing step is,
A method of manufacturing a cell, discharging the electrolyte solution injected into the pouch. According to claim 7,
The degassing step is,
A cell manufacturing method further comprising an electrolyte replenishment step of replenishing the electrolyte insufficient inside the pouch on which initial degassing has been completed. According to claim 7,
The additional degassing step is,
A cell manufacturing method that is carried out multiple times. According to claim 10,
The degassing step is,
A cell manufacturing method preceding the additional degassing multiple times and further comprising an additional electrolyte replenishment step of replenishing the insufficient electrolyte solution inside the pouch. A pouch cell produced by the method according to any one of claims 1 to 11.

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