Method for impregnating secondary battery with electrolyte

Abstract

The present invention relates to a method for impregnating a secondary battery with an electrolyte and, more specifically, to a method for impregnating a secondary battery with an electrolyte, the method being characterized by comprising the steps of: storing a secondary battery in a pressurized chamber; and adjusting the pressure inside the pressurized chamber, wherein in the step of adjusting the pressure, a pressurization step and a pressurization release step are performed two or more times.

Description

Electrolyte impregnation method for secondary batteries

[0001] This application claims the benefit of priority to Korean Patent Application No. 2024-0007636, filed January 17, 2024, the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to a method for impregnating a secondary battery with an electrolyte, and more specifically, to a method for impregnating a secondary battery with an electrolyte, which comprises alternately performing a pressurization step and a depressurization step in a chamber containing a secondary battery, but omitting a vacuum depressurization step for adjusting the pressure below atmospheric pressure, thereby increasing the electrolyte impregnation rate and reducing the waiting time for each step, thereby contributing to increasing the efficiency of the impregnation process.

[0003]

[0004] Secondary batteries are an alternative energy source to fossil fuels that cause air pollutants, and are being applied to electric vehicles (EVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (P-HEVs), and energy storage devices (ESS).

[0005] Commonly used battery cell types today include lithium-ion batteries, lithium polymer batteries, nickel-cadmium batteries, nickel-metal hydride batteries, and nickel-zinc batteries. These unit secondary battery cells are typically connected in series or parallel to form battery modules, depending on the required output voltage or charge / discharge capacity.

[0006] Meanwhile, lithium secondary batteries can be classified into can-type secondary batteries in which the electrode assembly is built into a metal can and pouch-type secondary batteries in which the electrode assembly is built into a pouch of an aluminum laminate sheet, depending on the shape of the battery case.

[0007] These lithium secondary batteries are manufactured through a step of inserting an electrode assembly consisting of a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode into a battery case and injecting a liquid electrolyte, i.e., an electrolyte solution.

[0008] The injected electrolyte permeates between the anode, cathode, and separator that make up the electrode assembly by capillary force, but impregnation of the electrolyte is not easy due to the characteristics of the porous separator, which is a microstructure.

[0009] If the electrolyte is not sufficiently impregnated into the electrode assembly, the charging / discharging efficiency due to lithium ions, etc. decreases, which not only reduces battery performance but also causes capacity deviations between battery cells.

[0010] In this regard, Korean Patent Publication No. 2016-0130646 discloses an electrolyte impregnation method including a step of supplying an electrolyte in a vapor state by reducing pressure to a cell including an electrode assembly, a step of condensing the electrolyte in a vapor state supplied to the cell, and a step of combining the electrolyte in a vacuum atmosphere.

[0011] In addition, Korean Patent Publication No. 2019-0091048 discloses an electrolyte impregnation method, including the steps of: placing a secondary battery in which an electrolyte is injected into an electrode assembly in the internal space of an impregnation chamber; pressurizing the internal space of the impregnation chamber to impregnate the electrode assembly with the electrolyte under a pressurized atmosphere for a predetermined pressurization time; and depressurizing the internal space of the impregnation chamber to impregnate the electrode assembly with the electrolyte under a vacuum atmosphere for a predetermined depressurization time.

[0012] That is, in the conventional technology of impregnating a battery cell with an electrolyte, the process includes a depressurization and pressurization process after injecting the electrolyte.

[0013] However, in a depressurized atmosphere lower than atmospheric pressure, pressurization, or depressurization after pressurization, the waiting time until each unit process starts is long, making the impregnation process inefficient.

[0014] In addition, in the case of cylindrical secondary batteries, as the size increases, the electrolyte impregnation property in the central portion of the jelly-roll electrode assembly may decrease.

[0015]

[0016] (Prior art literature)

[0017] (Patent Document 1) Korean Patent Publication No. 2016-0130646

[0018] (Patent Document 2) Korean Patent Publication No. 2019-0091048

[0019]

[0020] In order to solve the above problems, the present invention aims to provide a method for impregnating a secondary battery with an electrolyte that can improve the impregnation property of the electrolyte.

[0021] Another object of the present invention is to provide a method for impregnating a secondary battery with an electrolyte capable of reducing the waiting time.

[0022]

[0023] In order to achieve the above purpose, the method for impregnating a secondary battery with an electrolyte according to the present invention comprises the steps of: housing a secondary battery in a pressurized chamber; and controlling the pressure inside the pressurized chamber; wherein, in the step of controlling the pressure, the pressurizing step and the depressurizing step are performed two or more times.

[0024] In addition, in the method for impregnating an electrolyte of a secondary battery according to the present invention, the pressure controlling step is characterized in that a first pressurizing step, a first pressurizing release step, a second pressurizing step, and a second pressurizing release step are sequentially performed.

[0025] In addition, in the electrolyte impregnation method of a secondary battery according to the present invention, it is characterized in that a third pressurizing step and a third pressurizing releasing step are further performed after the second pressurizing releasing step.

[0026] In addition, in the electrolyte impregnation method of a secondary battery according to the present invention, it is characterized in that a fourth pressurization step and a fifth pressurization step are further performed after the third pressurization release step.

[0027] In addition, in the electrolyte impregnation method of a secondary battery according to the present invention, the pressing force in the first pressing step and the second pressing step is characterized in that it is in the range of 600 to 750 kPa, respectively.

[0028] In addition, in the electrolyte impregnation method of a secondary battery according to the present invention, the pressurization maintenance time in the first pressurization step and the second pressurization step is characterized in that it is in the range of 60 to 360 seconds, respectively.

[0029] In addition, in the electrolyte impregnation method of a secondary battery according to the present invention, the pressurizing time of the second pressurizing step is set to be longer than the pressurizing maintenance time of the first pressurizing step.

[0030] In addition, in the electrolyte impregnation method of a secondary battery according to the present invention, the pressing force in the first pressing step, the second pressing step, and the third pressing step is characterized in that it is in the range of 600 to 750 kPa, respectively.

[0031] In addition, in the electrolyte impregnation method of a secondary battery according to the present invention, the pressurization maintenance times in the first pressurization step, the second pressurization step, and the third pressurization step are each in the range of 60 to 360 seconds.

[0032] In addition, in the electrolyte impregnation method of a secondary battery according to the present invention, the pressurization maintenance time is set to be long in the order of the first pressurization step, the second pressurization step, and the third pressurization step.

[0033] In addition, in the electrolyte impregnation method of a secondary battery according to the present invention, it is characterized in that a depressurization step in which the inside of the pressurized chamber is below atmospheric pressure is not included.

[0034] In addition, in the electrolyte impregnation method of a secondary battery according to the present invention, the secondary battery is characterized in that it has a cylindrical or square shape.

[0035] In addition, the present invention is characterized by being a secondary battery impregnated by the aforementioned electrolyte impregnation method.

[0036]

[0037] As described above, according to the electrolyte impregnation method of a secondary battery according to the present invention, the electrolyte impregnation rate can be increased by alternately performing a pressurization step and a depressurization step in a chamber in which a secondary battery is stored.

[0038] In addition, according to the electrolyte impregnation method of a secondary battery according to the present invention, the vacuum decompression step for adjusting the pressure below atmospheric pressure is omitted, so that the waiting time of each step can be reduced, which can contribute to increasing the efficiency of the impregnation process.

[0039] In addition, according to the method for impregnating an electrolyte of a secondary battery according to the present invention, the vacuum decompression step for adjusting the pressure below atmospheric pressure is omitted, so that the operating and management items of the device can be reduced, which can contribute to improving the working environment.

[0040]

[0041] Figure 1 is a perspective view of a chamber for impregnating an electrolyte.

[0042] Figure 2 is a front view of the impregnation chamber shown in Figure 1.

[0043] Figure 3 is a side view of the impregnation chamber shown in Figure 1.

[0044] Figure 4 is a perspective view of a pallet for storing secondary batteries.

[0045] Figure 5 is a photograph of a disassembled battery cell after the impregnation process has been completed according to Example 1.

[0046] Figure 6 is a photograph of a disassembled battery cell after the impregnation process has been completed according to Example 2.

[0047] Figure 7 is a photograph of a disassembled battery cell after the impregnation process has been completed according to Example 3.

[0048] Figure 8 is a photograph of a disassembled battery cell in which the impregnation process has been completed according to Example 4.

[0049] Figure 9 is a photograph of a disassembled battery cell in which the impregnation process has been completed according to Example 5.

[0050] Figure 10 is a photograph of a disassembled battery cell after the impregnation process has been completed according to a comparative example.

[0051]

[0052] Hereinafter, with reference to the attached drawings, embodiments of the present invention will be described in detail, so that those skilled in the art can easily implement the present invention. However, when describing the operating principles of preferred embodiments of the present invention in detail, if a detailed description of a related known function or configuration is judged to unnecessarily obscure the gist of the present invention, such detailed description will be omitted.

[0053] Additionally, the same drawing reference numerals are used for parts with similar functions and actions throughout the drawings. Throughout the specification, when a part is said to be connected to another part, this includes not only direct connections but also indirect connections with other elements intervening. Furthermore, inclusion of a component does not exclude other components unless specifically stated otherwise, but rather implies the inclusion of additional components.

[0054]

[0055] The method for impregnating a secondary battery with an electrolyte according to the present invention includes a step of housing the secondary battery in a pressurized chamber and a step of controlling the pressure inside the pressurized chamber, but does not include a vibration step in which the inside of the pressurized chamber is at a pressure below atmospheric pressure.

[0056] In detail, in the pressure control step, it is preferable that a pressurization step and a depressurization step for lowering the pressure to near atmospheric pressure be performed at least twice.

[0057] For example, the pressure control step may be performed sequentially as a first pressurization step, a first pressurization release step, a second pressurization step, and a second pressurization release step.

[0058] As another example, a first pressurization step, a first depressurization step, a second pressurization step, a second depressurization step, a third pressurization step, and a third depressurization step may be performed sequentially.

[0059] As another example, a first pressurization step, a first depressurization step, a second pressurization step, a second depressurization step, a third pressurization step, a third depressurization step, a fourth pressurization step, and a fifth depressurization step may be performed sequentially.

[0060] Of course, it is self-evident that the pressurization and depressurization steps can be performed more repeatedly after the fifth depressurization step.

[0061] Meanwhile, the pressing force at each pressing step is preferably 600 to 750 kPa. If it is less than 600 kPa, the electrolyte impregnation rate is low, and conversely, if it exceeds 750 kPa, the electrode assembly may be damaged or the manufacturing cost of the pressing chamber may increase significantly. Therefore, the pressing force is preferably within the above range.

[0062] The pressurization holding time at each pressurization stage can be 60 to 360 seconds, and it is desirable that the pressurization holding time at each pressurization stage be similar, and it is more desirable that the pressurization holding time becomes longer as the pressurization stage progresses.

[0063] The secondary battery of the present invention is not particularly limited as long as it is a lithium secondary battery, and may be, for example, a cylindrical secondary battery, a square secondary battery, or a pouch-type secondary battery.

[0064]

[0065] Fig. 1 is a perspective view of a chamber for impregnating an electrolyte, Fig. 2 is a front view of the impregnation chamber shown in Fig. 1, and Fig. 3 is a side view of the impregnation chamber shown in Fig. 1.

[0066] A chamber for impregnating the electrode assembly of a secondary battery with an electrolyte may be a movable chamber as illustrated in FIGS. 1 to 3. Of course, there are no particular limitations on the chamber as long as it can pressurize the secondary battery at a certain pressure and release the pressurized pressure.

[0067] As illustrated in FIGS. 1 to 3, the electrolyte impregnation chamber may be configured to include a chamber body (100) for storing a secondary battery, a chamber frame (200) shaped to surround the chamber body (100), an air cylinder (300) for moving a portion of the chamber body (100) up and down, and a control unit (400) for operating the air cylinder (300).

[0068] First, the chamber body (100) is composed of a lower body (110) and an upper body (120), and the lower body (110) may have a roughly circular plate-like structure. The upper body (120) is positioned above the lower body (110) and operates to be raised and lowered, and the overall external shape may be a hemispherical or semi-elliptical shape with an empty interior.

[0069] A secondary battery for impregnation of an electrolyte is stored on the upper surface of the lower body (110), and since pressurization and depressurization must be performed alternately, it is preferable that the upper body (120) and the lower body (110) be sealed so that they can be sealed from the outside when they are in close contact, and that they are structured so that they do not separate even when a certain amount of pressure is applied to the inside.

[0070] Although not shown in the drawing, the lower body (110) and / or the upper body (120) are provided with a port (not shown) for supplying gas into the chamber to pressurize it to a certain pressure or for exhausting the gas to the outside.

[0071] The chamber frame (200) may be configured to include a vertical frame (210), a horizontal frame (220), a support plate (230), and a guide frame (240).

[0072] The vertical frames (210) are formed as a pair and are positioned to face each other with the chamber body (100) in between. At this time, the vertical frames (210) positioned on each side are two each and are positioned at a predetermined interval. Therefore, the vertical frames (210) may be formed in total of four, but are not limited thereto.

[0073] The horizontal frame (220) is fixed to the upper portion of the four vertical frames (210) and may have a roughly square plate-shaped structure.

[0074] The support plate (230) is located between the horizontal frame (220) and the upper body (120), and moves up and down by the operation of the air cylinder (300) while fixing and supporting the upper body (120). Specifically, it has a plate-like structure similar to the horizontal frame (220), and a piston rod (350) is connected near the edges on both sides facing each other, while the upper body (120) is connected near the central bottom.

[0075] Accordingly, when the piston rod (350) descends or rises, the support plate (230) moves up and down together with the upper body (120) in a suspended state.

[0076] The guide frame (240) is intended to guide the support plate (230) so that it can move up and down stably, and can be positioned to penetrate the support plate (230) in a vertical direction. Specifically, the lower end of the guide frame (240) is positioned to be in contact with the ground facing downwards, and the other end is positioned to be in contact with the bottom surface of the horizontal frame (220), and is roughly shaped like a rod. It can be composed of four guide frames that penetrate each corner of the horizontal frame (220), but the number can be increased or decreased as needed.

[0077] The control unit (400) determines the operation of the air cylinder (300) by controlling the supply and exhaust of gas.

[0078] Figure 4 is a perspective view of a pallet for storing secondary batteries. The secondary batteries stored in the pallet are filled with electrolyte with the top open. Any change to the pallet's capacity is possible.

[0079]

[0080] Hereinafter, the present invention will be described in more detail through examples and experimental examples. However, these examples are only intended to aid understanding of the present invention and are not intended to limit the scope of the present invention in any way.

[0081]

[0082] Example 1

[0083] A pallet (see Fig. 4) storing a plurality of cylindrical secondary batteries (21700) in a state of electrolyte injection was loaded onto a lower body having a configuration similar to Fig. 1, and then the upper body was lowered so that the cylindrical secondary batteries were sealed from the outside, and the lower bodies were brought into close contact with each other.

[0084] Afterwards, the electrolyte was impregnated in the following order: first pressurization stage, first depressurization stage, second pressurization stage, second depressurization stage, third pressurization stage, and third depressurization stage.

[0085] In the first pressurization step, nitrogen gas was supplied into the chamber so that the internal pressure of the pressurized chamber became 680 kPa, and the pressure was maintained for 180 seconds from the time 680 kPa was reached. In the first depressurization step, nitrogen gas was exhausted so that the internal pressure of the chamber became equal to atmospheric pressure.

[0086] In the second pressurization step, nitrogen gas was supplied into the chamber so that the internal pressure of the pressurized chamber became 680 kPa, and the pressure was maintained for 230 seconds from the time 680 kPa was reached. In the second depressurization step, nitrogen gas was exhausted so that the internal pressure of the chamber became equal to atmospheric pressure.

[0087] In addition, in the third pressurization stage, nitrogen gas was supplied into the chamber so that the internal pressure of the pressurized chamber became 680 kPa, and the pressure was maintained for 280 seconds from the time 680 kPa was reached. In the third depressurization stage, nitrogen gas was exhausted so that the internal pressure of the chamber became the same as atmospheric pressure.

[0088]

[0089] Example 2

[0090] The process was carried out in the order of a first pressurization step, a first pressurization release step, a second pressurization step, a second pressurization release step, a third pressurization step, and a third pressurization release step. The internal pressure of each of the first to third pressurization steps was set to be the same at 650 kPa, and the holding time was also set to be the same at 180 seconds, except that the rest was carried out in the same manner as in Example 1 to impregnate the electrolyte.

[0091]

[0092] Example 3

[0093] The process was carried out in the following order: first pressurization stage, first pressurization release stage, second pressurization stage, second pressurization release stage, third pressurization stage, third pressurization release stage, fourth pressurization stage, and fourth pressurization release stage. The internal pressure of each of the first to fourth pressurization stages was set to be the same at 700 kPa, and the holding time was also set to be the same at 120 seconds. The rest was carried out in the same manner as in Example 1 to impregnate the electrolyte.

[0094]

[0095] Example 4

[0096] The process was carried out in the following order: first pressurization stage, first pressurization release stage, second pressurization stage, second pressurization release stage, third pressurization stage, and third pressurization release stage. The internal pressure of each of the first to third pressurization stages was set to be the same at 700 kPa, and the holding time was also set to be the same at 180 seconds. The rest was carried out in the same manner as in Example 1 to impregnate the electrolyte.

[0097]

[0098] Example 5

[0099] The process proceeded in the following order: first pressurization stage, first depressurization stage, second pressurization stage, second depressurization stage, third pressurization stage, and third depressurization stage.

[0100] In the first pressurization step, the pressure inside the pressurization chamber was 700 kPa and maintained for 360 seconds. In the second pressurization step, the pressure inside the pressurization chamber was 700 kPa and maintained for 60 seconds. In addition, in the third pressurization step, the pressure inside the pressurization chamber was 700 kPa and maintained for 60 seconds, and the rest was carried out in the same manner as in Example 1 to impregnate the electrolyte.

[0101]

[0102] Comparative example

[0103] The electrolyte was impregnated in the following order: first depressurization step, first pressurization step, depressurization step, second pressurization step, second depressurization step, first depressurization step, third depressurization step, and second depressurization step.

[0104] In the first depressurization step, the air inside the chamber was exhausted to adjust the pressure to -90 kPa and maintained for 20 seconds. In the first pressurization step, nitrogen gas was supplied into the chamber so that the pressure inside the pressurized chamber reached 650 kPa, and the pressure was maintained for 200 seconds from the point where 650 kPa was reached. In the depressurization step, nitrogen gas was exhausted so that the inside of the chamber was equal to atmospheric pressure.

[0105] In the second pressurization stage, nitrogen gas was supplied into the chamber so that the internal pressure of the pressurized chamber became 650 kPa, and the pressure was maintained for 250 seconds from the time 650 kPa was reached.

[0106] In the second decompression step, the air inside the chamber was exhausted to adjust it to -30 kPa and maintained for 10 seconds, and in the first decompression step, outside air was introduced so that the inside of the chamber was at the same pressure as the atmospheric pressure.

[0107] In addition, in the third decompression stage, the air inside the chamber was exhausted to adjust it to -30 kPa and maintained for 10 seconds, and in the second decompression stage, outside air was introduced so that the inside of the chamber was at the same pressure as the atmospheric pressure.

[0108]

[0109] Impregnation Conditions Example 1 Pressurization (180s, 680kPa) - Depressurization - Pressurization (230s, 680kPa) - Depressurization - Pressurization (280s, 680kPa) - Depressurization Example 2 Pressurization (180s, 650kPa) - Depressurization - Pressurization (180s, 650kPa) - Depressurization - Pressurization (180s, 650kPa) - Depressurization Example 3 Pressurization (120s, 700kPa) - Depressurization - Pressurization (120s, 700kPa) - Depressurization - Pressurization (120s, 700kPa) - Depressurization Example 4 Pressurization (180s, 700kPa) - Depressurization - Pressurization (180s, 700kPa) - Depressurization - Pressurization (180s, 700kPa) - DepressurizationExample 5 Pressurization (360s, 700kPa) - Depressurization - Pressurization (60s, 700kPa) - Depressurization - Pressurization (60s, 700kPa) - DepressurizationComparative Example Depressurization (20s, -90kPa) - Pressurization (200s, 650kPa) - Depressurization - Pressurization (250s, 650kPa) - Depressurization (10s, -30kPa) - Depressurization - Depressurization (10s, -30kPa) - Depressurization

[0110]

[0111] Exam example

[0112] After disassembling the cylindrical battery cell after completing the electrolyte impregnation process under the conditions of the examples and comparative examples, the portion not impregnated with the electrolyte was visually examined.

[0113] Fig. 5 is a photograph of a battery cell disassembled after the impregnation process was completed according to Example 1, Fig. 6 is a photograph of a battery cell disassembled after the impregnation process was completed according to Example 2, and Fig. 7 is a photograph of a battery cell disassembled after the impregnation process was completed according to Example 3. Also, Fig. 8 is a photograph of a battery cell disassembled after the impregnation process was completed according to Example 4, and Fig. 9 is a photograph of a battery cell disassembled after the impregnation process was completed according to Example 5. Fig. 10 is a photograph of a battery cell disassembled after the impregnation process was completed according to a comparative example.

[0114] The marked portions in Figures 5 to 10 indicate portions that are not impregnated with electrolyte, and the remaining portions indicate portions that are impregnated with electrolyte.

[0115] First, looking at Fig. 10, which is a comparative example result, it can be confirmed that a wide area of ​​the separator is not wetted by the electrolyte when the jelly roll is unfolded.

[0116] On the other hand, in the results of Examples 1 to 5, Figs. 5 to 10, it can be seen that the area not wetted by the electrolyte has been significantly reduced. In particular, as can be seen in Figs. 5 and 8, when the holding time in each pressurization step is set to be the same or when the holding time is set to become longer as time goes on, it can be seen that the electrolyte impregnation rate is improved.

[0117]

[0118] Anyone with ordinary skill in the art to which the present invention pertains will be able to perform various applications and modifications within the scope of the present invention based on the above contents.

[0119] (Explanation of symbols)

[0120] 100: Chamber body

[0121] 110: Lower body

[0122] 120: Upper body

[0123] 200: Chamber Frame

[0124] 210: Vertical frame

[0125] 220: Horizontal frame

[0126] 230: Support plate

[0127] 240: Guide Frame

[0128] 300: Air cylinder

[0129] 310: Cylinder tube

[0130] 320: Head cover

[0131] 330: Road cover

[0132] 350: Piston rod

[0133] 400: Control Unit

[0134] 500: Palette

[0135] B: Secondary battery

[0136] L1: Gas pipeline 1

[0137] L2: Second gas pipeline

Claims

1. A step of storing a secondary battery in a pressurized chamber; and A step of regulating the pressure inside the pressurized chamber; Including, A method for impregnating an electrolyte of a secondary battery, characterized in that in the step of controlling the pressure, the pressurizing step and the depressurizing step are performed at least twice.

2. In paragraph 1, A method for impregnating an electrolyte of a secondary battery, characterized in that in the step of controlling the pressure, a first pressurizing step, a first pressurizing release step, a second pressurizing step, and a second pressurizing release step are performed sequentially.

3. In paragraph 2, A method for impregnating an electrolyte of a secondary battery, characterized in that a third pressurizing step and a third pressurizing release step are further performed after the second pressurizing release step.

4. In paragraph 3, A method for impregnating an electrolyte of a secondary battery, characterized in that a fourth pressurizing step and a fifth pressurizing step are further performed after the third pressurizing step.

5. In paragraph 2, A method for impregnating an electrolyte of a secondary battery, characterized in that the pressurizing forces in the first pressurizing step and the second pressurizing step are each in the range of 600 to 750 kPa.

6. In paragraph 5, A method for impregnating an electrolyte of a secondary battery, characterized in that the pressurization maintenance times in the first pressurization step and the second pressurization step are each in the range of 60 to 360 seconds.

7. In paragraph 6, A method for impregnating an electrolyte of a secondary battery, characterized in that the pressurizing time of the second pressurizing step is set longer than the pressurizing maintenance time of the first pressurizing step.

8. In paragraph 3, A method for impregnating an electrolyte of a secondary battery, characterized in that the pressurizing forces in the first pressurizing step, the second pressurizing step, and the third pressurizing step are each in the range of 600 to 750 kPa.

9. In paragraph 8, A method for impregnating an electrolyte of a secondary battery, characterized in that the pressurization maintenance times in the first pressurization step, the second pressurization step, and the third pressurization step are each in the range of 60 to 360 seconds.

10. In paragraph 9, A method for impregnating an electrolyte of a secondary battery, characterized in that the pressurization maintenance time is set to be long in the order of the first pressurization stage, the second pressurization stage, and the third pressurization stage.

11. In paragraph 1, A method for impregnating an electrolyte of a secondary battery, characterized in that the method does not include a depressurization step in which the inside of the pressurized chamber is at a pressure below atmospheric pressure.

12. In paragraph 1, A method for impregnating an electrolyte in a secondary battery, characterized in that the secondary battery is cylindrical or square.

13. A secondary battery impregnated with an electrolyte impregnation method according to any one of claims 1 to 12.

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