Method for manufacturing a secondary battery including split injection of an electrolytic solution

Abstract

The present invention relates to a method for manufacturing a secondary battery, and the method for manufacturing the secondary battery comprises injecting a large capacity electrolyte solution in two separate injections, and correcting the amount of electrolyte solution injected in the second injection to reflect the average amount of electrolyte solution injected in the past. This allows the electrolyte solution to be injected quantitatively within a short period of time, and therefore has the advantage of significantly reducing the defective rate when manufacturing batteries injected with 200 g or more of electrolyte solution, such as large capacity secondary batteries or long cell model secondary batteries, as well as further improving the performance of the secondary battery.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a secondary battery including split injection of an electrolytic solution.

[0002] This application claims the benefit of priority based on Korean Patent Application No. 10-2021-0149103 filed on November 2, 2021, and all contents disclosed in the document of the Korean patent application are incorporated herein by reference.

Background Art

[0003] With the development of electronic devices, secondary batteries have come into the spotlight as their energy source. Recently, lithium secondary batteries and the like are used as power sources for medium and large-sized devices such as electric vehicles, and thus the performance of secondary batteries is considered as a main factor influencing the performance of electronic devices and medium and large-sized devices.

[0004] A secondary battery is manufactured by fabricating and assembling an electrode assembly including a positive electrode, a negative electrode, and a separator, inserting the electrode assembly into a battery case such as a pouch, injecting an electrolytic solution into the case, and then sealing it. Here, in the process of injecting the electrolytic solution, since the performance of the battery is determined by the impregnation state of the electrolytic solution injected into the battery case, it is important to inject the electrolytic solution more quantitatively. For this purpose, a considerable amount of time is required in the process of manufacturing the battery.

[0005] However, recently, with the increasing use of large-capacity secondary batteries and long cell models that require a significant amount of electrolyte to be injected, attempts have been continuously made to inject an accurate amount of electrolyte in a shorter period of time. As an example, a technique has been developed to inject and impregnate the electrolyte in a short time by injecting the electrolyte into a fixed battery case at a high vacuum pressure at a high injection speed at once. However, the above technique has a problem that when the amount of the electrolyte is increased to 200 g or more, the electrolyte is not quantitatively injected. To solve such a problem, when performing two-stage split injection and increasing the injection speed, the amount of the injected electrolyte is quantitatively controlled, but due to the high injection speed, a collision phenomenon of the battery cells occurs, and the injected electrolyte flies outside, resulting in loss of the electrolyte and contamination inside and outside the case. Therefore, a technique that can quantitatively inject the electrolyte into a large-capacity battery of 200 g or more without contaminating the inside and outside of the battery in a short time is required.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] Therefore, an object of the present invention is to provide a technique capable of quantitatively injecting a large-capacity electrolyte of 200 g or more into a battery case in a short time during the manufacture of a secondary battery.

Means for Solving the Problems

[0008] To solve the above problems, In one embodiment, the present invention a step of first injecting the electrolyte into a battery case in which an electrode assembly is inserted in a predetermined injection amount; a step of second injecting the electrolyte into the battery case into which the electrolyte has been first injected; sealing the battery case into which the electrolytic solution is secondarily injected, and provided is a method for manufacturing a secondary battery in which, when the electrolytic solution is secondarily injected, if the electrolytic solution injection is performed for the (n + 1)-th time, a correction value is calculated from the average value of the electrolytic solution injection amounts primarily injected from the (n - a)-th time (where a is an integer satisfying 10 ≤ a ≤ 20) to the n-th time, and the calculated correction value is reflected in a predetermined secondary electrolytic solution injection amount for determination.

[0009] Here, the average value of the electrolytic solution injection amounts primarily injected is obtained by calculating an average injection value A and a standard deviation σ of the electrolytic solution injection amounts primarily injected from the (n - a)-th time (where a is an integer satisfying 10 ≤ a ≤ 20) to the n-th time, setting a confidence interval from the calculated average injection value A and standard deviation σ, and selecting only the values belonging to the set confidence interval among the a electrolytic solution injection amounts primarily injected used in the calculation of the average injection value A and the standard deviation σ, and calculating a confidence interval average value which is the average value of the selected values.

[0010] Further, the correction value may be the deviation between the sum of the confidence interval average value of the primary electrolytic solution injection amount and the predetermined secondary electrolytic solution injection amount and the total electrolytic solution injection amount.

[0011] Further, the method for manufacturing the secondary battery is performed using a pump-type injection device that injects the electrolytic solution through a syringe, and the electrolytic solution injection amount for secondary injection can be adjusted by calculating a drive value of the syringe according to the correction value and operating the syringe by reflecting the calculated drive value in a predetermined syringe drive value.

[0012] In addition, the method for manufacturing the secondary battery according to the present invention may further include a step of measuring the amount of the electrolytic solution primarily injected after the step of primarily injecting the electrolytic solution into the battery case, or may further include a step of storing the measured primary electrolytic solution injection amount after the step of measuring the amount of the electrolytic solution primarily injected.

[0013] Also, the injection amount of the electrolytic solution to be secondarily injected may be 10 to 60% by weight based on the total injection amount of the electrolytic solution, and specifically, it may be 20 to 40% by weight based on the total injection amount of the electrolytic solution.

[0014] Also, the total amount of the electrolytic solution injected into the battery case may be 200 g or more.

[0015] Also, the total time for injecting the total electrolytic solution into the battery case may be less than 3 seconds.

Advantages of the Invention

[0016] The method for manufacturing a secondary battery according to the present invention injects a large-capacity electrolytic solution in two portions, and corrects the secondary injection amount of the electrolytic solution by reflecting the average value of the primary injection amount of the electrolytic solution injected previously. Thus, the electrolytic solution can be quantitatively injected within a short time. Therefore, when manufacturing a battery that injects 200 g or more of electrolytic solution, such as a large-capacity secondary battery or a secondary battery of a long cell model, not only can the defective rate be significantly reduced, but also the performance of the secondary battery can be further improved.

Embodiments for Carrying Out the Invention

[0017] The present invention can be subjected to various modifications and may have various embodiments. However, specific embodiments will be described in detail hereinafter.

[0018] However, this is not intended to limit the present invention to specific embodiments, and it should be understood to include all modifications, equivalents, or alternatives included in the spirit and technical scope of the present invention.

[0019] In the present invention, terms such as "including" and "having" are intended to specify the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, and should be understood not to preclude the presence or addition possibility of one or more other features, numbers, steps, operations, components, parts, or combinations thereof in advance.

[0020] In the present invention, when a part such as a layer, a film, a region, a plate, etc. is described as being "above" another part, this includes not only the case where it is "directly above" the other part but also the case where there is another part in between. Conversely, when a part such as a layer, a film, a region, a plate, etc. is described as being "below" another part, this includes not only the case where it is "directly below" the other part but also the case where there is another part in between. Also, in the present application, being "disposed above" may include not only the upper part but also the case of being disposed below.

[0021] In the present invention, "ppm" refers to the number of secondary batteries produced per minute, which can indicate the process efficiency. For example, 15 ppm may mean producing 15 secondary batteries per minute.

[0022] In the present invention, "total liquid injection time" means the time for injecting the electrolyte into the battery case through the syringe of the liquid injection device when injecting the electrolyte into the battery case. At this time, the amount of the injected electrolyte may be calculated, and the time for adjusting the piston of the syringe according to the calculated electrolyte amount may be excluded.

[0023] Hereinafter, the present invention will be described in more detail.

[0024] <Method for manufacturing a secondary battery> In one embodiment, the present invention includes a step of first injecting an electrolyte into a battery case with the inserted electrode assembly in a predetermined injection amount, a step of second injecting an electrolyte into the battery case that has been first injected with the electrolyte, and a step of sealing the battery case that has been second injected with the electrolyte. When the electrolyte is second injected for the (n + 1)-th time, the injection amount of the electrolyte for the second injection is determined by calculating a correction value from the average value of the injection amounts of the electrolyte first injected from the (n - a)-th time (where a is an integer satisfying 10 ≤ a ≤ 20) to the n-th time and reflecting the calculated correction value in the predetermined electrolyte injection amount. A method for manufacturing a secondary battery is provided.

[0025] The manufacturing method of the secondary battery according to the present invention is a manufacturing method in which an electrolytic solution is injected through a pump-type injection device that injects the electrolytic solution through a syringe, and includes a step of injecting the electrolytic solution into a battery case into which an electrode assembly is inserted twice. Specifically, the manufacturing method includes a step of primarily injecting the electrolytic solution into the battery case into which the electrode assembly is inserted with a predetermined injection amount, a step of secondarily injecting the electrolytic solution into the battery case into which the electrolytic solution has been primarily injected, and a step of sealing the battery case into which the electrolytic solution has been secondarily injected.

[0026] By injecting a large amount of electrolytic solution twice, the present invention can more quantitatively control the total amount of the injected electrolytic solution compared to the case of injecting the electrolytic solution at one time, and can improve the work processability and productivity compared to the case of dividing and injecting the electrolytic solution three or more times.

[0027] Also, in the above manufacturing method, the step of primarily injecting the electrolytic solution is a process of first injecting the electrolytic solution according to a predetermined electrolytic solution injection amount. At this time, the existing fixed amount of the injected electrolytic solution may be 40 to 90% by weight based on the total amount of the electrolytic solution, and specifically, it may be 60 to 20% by weight. The present invention can prevent the correction error of the secondary injection amount from becoming large and the accuracy of the electrolytic solution injection amount from decreasing by adjusting the primary injection amount of the electrolytic solution to 40% by weight or more of the total amount of the electrolytic solution.

[0028] Most of the conventional technologies for dividing and injecting the electrolytic solution are performed in such a way that most of the electrolytic solution is injected during the primary injection, and then the insufficient part is supplemented from the total electrolytic solution injection amount during the secondary electrolytic solution injection. Therefore, the primary electrolytic solution injection amount exceeds 95%. However, in this case, although the total amount of the injected electrolytic solution is quantitatively controlled, since an additional electrolytic solution is injected into the battery case into which a considerable amount of the electrolytic solution has been injected with a high-pressure pump, the electrolytic solution can fly outside, resulting in loss of the electrolytic solution and contamination inside and outside the case, and the production efficiency of the battery corresponding to the electrolytic solution injection speed can be reduced due to the excessive primary electrolytic solution injection. However, the present invention can improve such problems by adjusting the primary injection amount of the electrolytic solution to 90% by weight or less of the total amount of the electrolytic solution.

[0029] The present invention can quantitatively inject an electrolytic solution at a high speed without contamination by the electrolytic solution by dividing and injecting an excessive amount of the electrolytic solution and using the average value of the amount of the electrolytic solution injected into the previous battery case during the secondary electrolytic solution injection.

[0030] Specifically, when the electrolytic solution injection is performed for the (n + 1)-th time, a correction value is calculated from the average value of the injection amounts of the electrolytic solution injected for the first time from the (n - a)-th time (where a is an integer satisfying 10 ≤ a ≤ 20) to the n-th time, and the injection amount of the electrolytic solution to be injected for the second time is determined by reflecting the calculated correction value.

[0031] Here, the average value of the injection amounts of the electrolytic solution injected for the first time can be derived from the amount of the electrolytic solution injected for the first time into the previous battery case. Specifically, it can be derived from the injection amounts of the primary electrolytic solution of the previous 10 to 20 battery cases of the battery case into which the electrolytic solution is being injected.

[0032] For example, the injection amount of the secondary electrolytic solution for the 21st battery case in which the electrolytic solution is injected in the secondary battery manufacturing process is obtained from the injection amounts of the primary electrolytic solution of 10 battery cases from the 11th battery case to the 20th battery case into which the electrolytic solution has been injected previously.

[0033] In addition, the average value of the injection amounts of the electrolytic solution injected for the first time is a step of calculating the average injection value A and the standard deviation σ of the injection amounts of the electrolytic solution injected for the first time from the (n - a)-th time (where a is an integer satisfying 10 ≤ a ≤ 20) to the n-th time; a step of setting a confidence interval from the calculated average injection value A and standard deviation σ; It is obtained by a step of selecting only the values belonging to the set confidence interval among the a injection amounts of the primary electrolytic solution used in the calculation of the average injection value A and the standard deviation σ, and calculating the confidence interval average value which is the average value of these.

[0034] Specifically, first, calculate the average injection value A (average) and the standard deviation σ of the electrolyte injection amount for the first injection into 10 to 20 previous battery cases filled with electrolyte, and a confidence interval CI (confidence interval) can be set from the calculated average injection value A and the standard deviation σ. Here, the above confidence interval is a range that reflects the standard deviation σ in the calculated average injection value A. The lower limit value may be larger than the value obtained by subtracting the standard deviation σ from the average injection value A, and the upper limit value may be smaller than the value obtained by adding the standard deviation σ to the average injection value A (A - σ < CI < A + σ). Next, select only the values that exist within the set confidence interval CI among the 10 to 20 first electrolyte injection amounts used to calculate the average injection value A and the standard deviation σ, and calculate the average value of the selected first electrolyte injection amounts to obtain the confidence interval average value CIA.

[0035] By using the confidence interval average value CIA calculated in this way as the average value of the electrolyte injection amount for the first injection, the present invention can significantly reduce the defect rate of the battery compared to the case of determining the secondary electrolyte injection amount by reflecting only the amount of the electrolyte injected into the battery case for the first injection.

[0036] Also, the average value of the electrolyte injection amount for the first injection, that is, the confidence interval average value CIA, is used to calculate the correction value. Specifically, the present invention can calculate the deviation between the total of the confidence interval average value of the first electrolyte injection amount and the preset secondary electrolyte injection amount and the total electrolyte injection amount as the correction value.

[0037] For example, when the preset values of the first electrolyte injection amount and the secondary electrolyte injection amount are 200 g and 100 g respectively, and the confidence interval average value CIA of the first electrolyte injection amount injected into the previous battery case is 200.1, a deviation of 0.1 g from the total electrolyte injection amount (300 g) can be calculated as the correction value.

[0038] The correction value calculated in this way is reflected in the preset secondary electrolyte injection amount, and the battery case may be secondarily injected with electrolyte with the secondary electrolyte injection amount reflecting the correction value.

[0039] Specifically, the method for manufacturing a secondary battery according to the present invention uses a pump-type injection device for injecting an electrolytic solution into a battery case via a syringe. The pump-type injection device includes a first syringe for primarily injecting the electrolytic solution into the battery case and a second syringe for secondarily injecting the electrolytic solution into the battery case into which the electrolytic solution has been primarily injected. The first syringe and the second syringe are each coupled with a high-pressure pump and configured to inject the electrolytic solution into the battery case in a predetermined amount. Here, for each of the syringes, the moving value of a piston provided inside according to a predetermined electrolytic solution injection amount is set to a unit of the electrolytic solution injection amount per 1 mm. The present invention can reflect the correction value in the injection amount of the secondary electrolytic solution injected into the battery case by converting the correction value into the electrolytic solution injection amount per 1 mm of the moving distance of the piston provided in the second syringe and reflecting this in the predetermined piston moving value of the second syringe and operating it.

[0040] On the other hand, the total amount of the electrolytic solution injected into the battery case in the present invention may be 200 g or more. Specifically, it may be 250 g or more, 300 g or more, 400 g or more, 200 to 1,000 g, 300 to 1,000 g, 200 to 500 g, 300 to 800 g, or 300 to 500 g.

[0041] Also, the injection amount of the electrolytic solution for secondary injection may be 10 to 60% by weight based on the total injection amount of the electrolytic solution. Specifically, it may be 20 to 40% by weight. The present invention can prevent the correction error of the secondary injection amount from becoming large and the accuracy of the electrolytic solution injection amount from decreasing by adjusting the secondary injection amount of the electrolytic solution to 10% by weight or more of the total amount of the electrolytic solution. Also, by adjusting the secondary injection amount of the electrolytic solution to 60% by weight or less of the total amount of the electrolytic solution, it is possible to prevent the inside and outside of the battery case from being contaminated due to the electrolytic solution during the secondary injection of the electrolytic solution and to prevent the production efficiency of the battery from decreasing.

[0042] Also, the time taken to fix the battery case into which the electrode assembly is inserted and inject all the electrolytic solution may be less than 3 seconds. Specifically, it may be 2.5 seconds or less, 2 seconds or less, 0.5 to 2.5 seconds, 1 to 2.5 seconds, or 1.5 to 2.5 seconds. In the present invention, the time taken from the step of primary injection of the electrolytic solution to the step of sealing the secondary battery into which the electrolytic solution has been injected includes the time for injecting the electrolytic solution into the secondary battery case (the sum of the primary injection time and the secondary injection time) and the injection volume calculation and control time for the secondary injection after the primary injection. The present invention can maximize the manufacturing efficiency and productivity of the secondary battery by adjusting the total time for injecting the electrolytic solution to be less than 3 seconds, and can prevent the performance degradation of the battery by minimizing the exposure time of the electrolytic solution in the air.

[0043] Further, in the method for manufacturing a secondary battery according to the present invention, after the step of primary injecting the electrolytic solution into the battery case, the step of measuring the amount of the electrolytic solution primary-injected may be further included.

[0044] Specifically, in the present invention, when the battery case is fixed / attached to the pump-type injection device used to inject the electrolytic solution into the battery case via a syringe, the weight of the battery case into which the electrode assembly has been inserted before injecting the electrolytic solution is measured. After the electrolytic solution is primary-injected into the battery case whose weight has been measured, the amount of the electrolytic solution primary-injected can be measured by continuously measuring the weight.

[0045] At this time, the measured primary electrolytic solution injection amount does not affect the electrolytic solution injection amount to be secondary-injected into the battery case, but can be measured for the correction of the secondary electrolytic solution injection amount of the battery case into which the electrolytic solution is to be injected thereafter. For this purpose, after the step of measuring the amount of the electrolytic solution primary-injected, the step of storing the measured primary electrolytic solution injection amount may be further included.

[0046] The method for manufacturing a secondary battery according to the present invention injects a large-capacity electrolyte in two portions, and corrects the secondary injection amount of the electrolyte by reflecting the average value of the primary injection amount of the electrolyte injected previously, so that the electrolyte can be quantitatively injected within a short time. Therefore, when manufacturing a battery that injects 200 g or more of electrolyte, such as a large-capacity secondary battery or a long-cell model secondary battery, not only can the defect rate be significantly reduced to a level of 15 ppm or less, but also the performance of the secondary battery can be further improved.

[0047] Hereinafter, the present invention will be described in more detail based on examples and comparative examples. However, the following examples and comparative examples are merely illustrative of the present invention, and the content of the present invention is not limited to the following examples and comparative examples.

[0048] (Examples 1 to 3) A secondary battery was manufactured using a pump-type electrolyte injection device including a first syringe for primarily injecting an electrolyte into a battery case and a second syringe for secondarily injecting the electrolyte into the battery case into which the electrolyte had been primarily injected, with a high-pressure pump coupled to each of the first syringe and the second syringe.

[0049] Specifically, 100 battery cases into which the electrode assembly was inserted were prepared, and the prepared battery cases were attached to the above-described pump-type electrolyte injection device. Then, 300 g of electrolyte was injected into each battery case, and the battery cases into which the electrolyte was injected were sealed to manufacture secondary batteries. At this time, when injecting the secondary electrolyte, before injecting the electrolyte into the battery case (the (n + 1)-th battery), the average injection value A and the standard deviation σ were calculated from the primary injection electrolyte injection amounts for 10 battery cases (the n-th to (n + 10)-th batteries) into which the electrolyte had been injected. After setting the confidence interval using the calculated average injection value A and standard deviation σ, values that satisfy the confidence interval were selected from among the 10 primary electrolyte injection amounts used to calculate the average injection value A, and their average values were derived as the confidence interval average value CIA. After combining the derived average value CIA with the predetermined secondary electrolyte injection amount, the deviation from the total electrolyte injection amount (300 g) was obtained as a correction value. The above correction value was converted into the electrolyte injection amount per 1 mm of the piston movement distance of the second syringe provided in the electrolyte injection device, and by reflecting this in the predetermined piston movement value of the second syringe and operating it, the injection amount of the secondary electrolyte injected into the battery case was adjusted.

[0050] Also, the conditions for the primary electrolyte injection and the secondary electrolyte injection were set as shown in Table 1 below, and the electrolyte was injected into 100 battery cases respectively. The total amount of the electrolyte finally injected into the manufactured secondary batteries was measured to evaluate the pump accuracy and the injection amount dispersion, and the results are shown in Table 1. Further, as a result of visually evaluating the appearance of each manufactured secondary battery, it was confirmed that the secondary battery of Example 3 had its internal and external appearances contaminated.

[0051]

Table 1

[0052] (Comparative Example 1) A secondary battery was manufactured using a pump-type electrolyte injection device including a syringe for injecting the electrolyte into the battery case, and the syringe was combined with a high-pressure pump.

[0053] Specifically, 100 battery cases with the electrode assembly inserted were prepared, and the prepared battery cases were attached to the above-described pump-type electrolyte injection device. Thereafter, 300 g of electrolyte was injected into each battery case once every 3 seconds, and the battery cases into which the electrolyte was injected were sealed to fabricate secondary batteries.

[0054] As a result of measuring the total amount of the electrolyte finally injected for the 100 fabricated secondary batteries, it was confirmed that the pump accuracy and the injection volume dispersion were ±0.5% and ±1.5 g, respectively. Such results mean that when injecting a large-capacity electrolyte of 200 g or more in a short time, the pump accuracy is high, but the amount of the electrolyte actually injected into the battery case is not uniform.

[0055] (Comparative Example 2) A secondary battery was fabricated using a pump-type electrolyte injection device including a first syringe for primary injection of the electrolyte into the battery case and a second syringe for secondary injection of the electrolyte into the battery case into which the electrolyte had been primarily injected, and a high-pressure pump was coupled to each of the first syringe and the second syringe.

[0056] Specifically, 100 battery cases with the electrode assembly inserted were prepared, and the prepared battery cases were attached to the above-described pump-type electrolyte injection device. Thereafter, 300 g of electrolyte was injected into each battery case, and the battery cases into which the electrolyte was injected were sealed to manufacture secondary batteries. At this time, the amount of the primary electrolyte injected into the battery case at the time of secondary electrolyte injection was measured, and the deviation between the measured amount of the primary electrolyte injection and the total amount of the electrolyte injection (300 g) was applied to the amount of the secondary electrolyte injection.

[0057] As a result of measuring the total amount of the electrolyte finally injected for the 100 fabricated secondary batteries, it was confirmed that the pump accuracy and the injection volume dispersion were ±0.5% and ±1.9 g, respectively. Such results mean that when injecting a large-capacity electrolyte of 200 g or more in a short time, the pump accuracy is high, but the amount of the electrolyte actually injected into the battery case is not uniform.

[0058] In the foregoing, the present invention has been described with reference to preferred embodiments thereof. However, it will be understood by those skilled in the art or those having ordinary knowledge in the art that the present invention can be variously modified and changed without departing from the spirit and technical scope of the present invention described in the claims.

[0059] Therefore, the technical scope of the present invention should not be limited to the content described in the detailed description of the specification, but should be determined by the claims.

Claims

1. A step of first injecting an electrolytic solution into a plurality of battery cases into which an electrode assembly is inserted at an injection amount of 90% by weight or less based on the total amount; A step of second injecting the electrolytic solution into the plurality of battery cases into which the electrolytic solution has been first injected; A step of sealing the plurality of battery cases into which the electrolytic solution has been second injected, and including: When the electrolytic solution is second injected up to the (n + 1)-th battery case, the injection amount of the electrolytic solution for the second injection is calculated by calculating a correction value from the average value of the injection amounts of the electrolytic solution first injected from the (n - a)-th (where a is an integer satisfying 10 ≤ a ≤ 20) to the n-th, and the calculated correction value is reflected in a predetermined second electrolytic solution injection amount and determined; The total amount of the electrolytic solution injected into each battery case is 200 g or more; The average value of the injection amounts of the electrolytic solution first injected is A step of calculating an average injection value A and a standard deviation σ of the injection amounts of the electrolytic solution first injected from the (n - a)-th (where a is an integer satisfying 10 ≤ a ≤ 20) to the n-th; A step of setting a confidence interval from the calculated average injection value A and the standard deviation σ; Only values belonging to the set confidence interval are selected from among the a injection amounts of the first electrolytic solution used in the calculation of the average injection value A and the standard deviation σ, and a confidence interval average value that is the average of these is obtained by a step of calculating; The correction value is the deviation between the sum of the confidence interval average value of the first electrolytic solution injection amount and the predetermined second electrolytic solution injection amount and the total electrolytic solution injection amount; A method for manufacturing a secondary battery.

2. The method for manufacturing a secondary battery is performed using a pump-type injection device that injects the electrolytic solution through a syringe, The injection amount of the electrolytic solution for the second injection is adjusted by calculating a driving value of the syringe corresponding to the correction value and operating the syringe by reflecting the calculated driving value in a predetermined syringe driving value. The method for manufacturing a secondary battery according to Claim 1.

3. After the step of first injecting the electrolytic solution into the battery case, The method for manufacturing a secondary battery according to Claim 1, further including a step of measuring the amount of the electrolytic solution first injected.

4. After the step of measuring the amount of the electrolytic solution first injected, The method for manufacturing a secondary battery according to Claim 3, further including a step of storing the measured first electrolytic solution injection amount.

5. The injection amount of the electrolytic solution for the second injection is 10 to 60% by weight based on the total injection amount of the electrolytic solution. The method for manufacturing a secondary battery according to Claim 1.

6. The injection amount of the electrolytic solution to be secondarily injected is 20 to 40% by weight based on the total injection amount of the electrolytic solution, and the method for manufacturing a secondary battery according to claim 1.

7. The total injection time of the electrolytic solution is less than 3 seconds, and the method for manufacturing a secondary battery according to any one of claims 1 to 6.

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