JP2019036504A - Method of manufacturing sealed battery - Google Patents

Abstract

To provide a method of manufacturing a sealed battery, enabling a proper inspection of airtightness of the sealed battery so that a sealed battery with high airtight reliability can be manufactured.SOLUTION: A method of manufacturing a sealed battery 1 includes: a liquid injection step S2 of injecting an electrolyte 17; a gas introduction step S3 of introducing a test gas GS1 into a battery case 10; an encapsulation step S4 of applying an airtight encapsulation to the batter case 10; a test gas detection step S5 of detecting an amount of leakage Q1 of the test gas GS1 leaked outside the battery; an electrolyte derivation gas detection step S8 of detecting an amount of leakage Q2 of an electrolyte derivation gas GS2 leaked outside the battery; and determination steps S6, S7, S9 to S11 having a first step to a third step of determining the airtightness of the sealed battery 1 on the basis of the amount of leakage Q1 and the amount of leakage Q2.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a method for manufacturing a sealed battery.

In a sealed battery such as a lithium ion secondary battery (hereinafter also simply referred to as “battery”), if the electrolyte leaks from the inside of the battery to the outside of the battery or moisture enters the inside of the battery from the outside of the battery, the battery performance deteriorates. Problems occur. For this reason, in the battery manufacturing process, it is necessary to check the airtightness of the battery and eliminate defective products.
Examples of the airtight inspection method include the following methods. That is, the electrolytic solution is injected into the battery case, and a test gas such as helium gas is introduced into the battery case, and then the battery case is hermetically sealed. Thereafter, the leakage amount of the inspection gas leaking from the inside of the battery to the outside of the battery is detected, and when the leakage amount is equal to or greater than the reference leakage amount, the battery is determined to be an airtight defect product. For example, Patent Document 1 discloses such a hermetic inspection method for a sealed battery (see the claims and background art of Patent Document 1).

JP2014-183027

  However, in the above-described airtight inspection method, when the leakage amount of the inspection gas is detected, if the electrolytic solution adheres to the airtight defective portion of the battery and the airtight defective portion is blocked with the electrolytic solution, the inspection is performed. It becomes difficult for the working gas to leak from the inside of the battery to the outside of the battery. For this reason, although the inspected battery is an airtight defective product having an airtight defective part such as a pinhole or a crack, there is a risk that the amount of leakage of the inspection gas is small, so that it is erroneously determined as a good product.

  The present invention has been made in view of the current situation, and provides a method for manufacturing a sealed battery that can appropriately check the hermeticity of a sealed battery and manufacture a sealed battery with high hermetic reliability. With the goal.

  One embodiment of the present invention for solving the above problems is a method for manufacturing a sealed battery, in which an electrolyte is injected into a battery case, and a test gas is introduced into the battery case. A gas introduction step, a sealing step for hermetically sealing the battery case after the liquid injection step and the gas introduction step, and the inspection gas leaking from the inside of the battery to the outside of the battery after the sealing step. Gas detection step for detecting the leakage amount Q1 of the electrolyte, and after the sealing step, the leakage from the inside of the battery to the outside of the battery. A gas detection step, and a determination step for determining the airtightness of the sealed battery based on the leakage amount Q1 of the inspection gas and the leakage amount Q2 of the electrolyte-derived gas. Inspection gas leak amount Q1 is the first reference leak When it is equal to or greater than Q1k (Q1 ≧ Q1k), the first step of determining the sealed battery as an airtight product and the sealed battery that is not determined as an airtight product in the first step When the difference (| Q1-Q2 |) between the leakage amount Q1 of the gas and the leakage amount Q2 of the electrolyte-derived gas is less than the reference difference ΔQk (| Q1-Q2 | <ΔQk), the sealed battery is hermetically sealed. The sealed battery in which the difference (| Q1-Q2 |) is determined to be equal to or greater than the reference difference ΔQk (| Q1-Q2 | ≧ ΔQk) in the second step in which the non-defective product is determined to be good. When the leakage amount Q2 of the electrolyte-derived gas is equal to or greater than the second reference leakage amount Q2k (Q2k ≦ Q1k) set to a value equal to or less than the first reference leakage amount Q1k (Q2 ≧ Q2k), the sealing Type battery is judged to be airtight and the leakage amount Q And a third step of determining the sealed battery as the non-defective product when 2 is less than the second reference leakage amount Q2k (Q2 <Q2k).

In the above-described sealed battery manufacturing method, after the sealing step, the amount Q1 of the inspection gas leaking from the inside of the battery to the outside of the battery is detected, and the electrolyte-derived gas leaking from the inside of the battery to the outside of the battery is leaked. The quantity Q2 is detected. The leakage amounts Q1 and Q2 are both expressed in units of “Pa · m ³ / sec”.
In the case of a battery with poor airtightness where an airtightness defective part has occurred, if electrolyte is attached to the airtightness defective part, it is difficult for the test gas to leak from the inside of the battery to the outside of the battery through this airtight defective part. Compared to the case where no electrolyte is attached to the portion, the amount of inspection gas leakage Q1 detected in the inspection gas detection step is reduced.

On the other hand, regarding the electrolyte-derived gas from which the electrolyte has volatilized, the electrolyte-derived gas leaks from the inside of the battery to the outside of the battery through the poorly sealed portion regardless of whether the electrolytic solution adheres to the poorly sealed portion. The leak amount Q2 of the electrolyte-derived gas detected in the liquid-derived gas detection step is not so different.
Accordingly, in the determination step, the airtightness of the battery is determined on the basis of both the leakage amount Q1 of the inspection gas and the leakage amount Q2 of the electrolyte-derived gas, thereby regardless of whether the electrolytic solution adheres to the poorly sealed portion. Therefore, the airtightness of the battery can be determined appropriately. Therefore, according to the manufacturing method described above, it is possible to manufacture a sealed battery with high hermetic reliability by appropriately checking the hermeticity of the sealed battery.

  In general, the measurement accuracy of the test gas sensor that detects the leak amount Q1 of the test gas is higher than the measurement accuracy of the electrolyte solution gas sensor that detects the leak amount Q2 of the electrolyte-derived gas. For this reason, for a specific test battery in which an airtight defect portion exists, when the leakage amount Q1 of the inspection gas and the leakage amount Q2 of the electrolyte-derived gas are repeatedly measured, the leakage amount Q1 of the inspection gas is used for the inspection gas. Compared with the measurement with the sensor, the variation in the measured value tends to increase when the leakage amount Q2 of the electrolyte-derived gas is measured with the sensor for the electrolyte-derived gas.

  For this reason, when determining the airtightness of the battery based on the leakage amount Q2 of the electrolyte-derived gas in the third step, if the value of the second reference leakage amount Q2k is too large, the defective product is regarded as a good product. There are many cases of erroneous determination. Therefore, it is conceivable that the value of the second reference leakage amount Q2k of the electrolyte-derived gas is set to a value that is small enough to prevent erroneous determination. However, in this case, the number of batteries that are judged as non-airtight products (hereinafter also referred to as “overdetermination”) increases, and the yield of the batteries decreases.

On the other hand, in the above-described method for manufacturing a sealed battery, prior to determining the airtightness of the battery based on the amount of leakage Q2 of the electrolyte-derived gas in the third step, When the difference (| Q1-Q2 |) between the gas leakage amount Q1 and the electrolyte-derived gas leakage amount Q2 is less than the reference difference ΔQk (| Q1-Q2 | <ΔQk), the battery is determined to be non-defective. . Then, only the battery in which the difference (| Q1-Q2 |) is determined to be greater than or equal to the reference difference ΔQk (| Q1-Q2 | ≧ ΔQk) in the second step proceeds to the third step.
Thus, in the above-described manufacturing method, the third step is not performed for a battery that is determined to be a non-defective product in the second step prior to the third step. For this reason, compared with the case where the 3rd process is performed without performing the 2nd process, the case where it is overdetermined that it is an airtight defect product in the 3rd process can be decreased. That is, according to the manufacturing method described above, the number of non-defective batteries that are over-determined to be airtight defects in the third step can be reduced, and the yield of batteries can be improved.

Examples of the “inspection gas” include helium gas and hydrogen gas.
In the “liquid injection process” and “gas introduction process”, the liquid injection process is performed first, the gas introduction process may be performed later, or the liquid injection process and the gas introduction process may be performed in parallel. .
The "inspection gas detection step" and the "electrolyte-derived gas detection step" may be performed first by performing the inspection gas detection step, and later by the electrolyte-derived gas detection step or by the electrolyte solution first. A gas detection step may be performed, and an inspection gas detection step may be performed later. Also, the inspection gas detection step and the electrolyte-derived gas detection step can be performed in parallel.

1 is a perspective view of a sealed battery according to an embodiment. It is a longitudinal cross-sectional view of the sealed battery which concerns on embodiment. It is a flowchart of the manufacturing method of the sealed battery which concerns on embodiment. It is explanatory drawing which shows the airtight test | inspection using an airtight test | inspection apparatus regarding the manufacturing method of the sealed battery which concerns on embodiment. It is a graph which shows the relationship between leak amount Q1 of helium gas, the leak amount Q2 of electrolyte solution origin gas, and frequency distribution in connection with embodiment.

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 are a perspective view and a longitudinal sectional view of a battery (sealed battery) 1 according to this embodiment. In the following description, the battery longitudinal direction BH, the battery lateral direction CH, and the battery thickness direction DH of the battery 1 are defined as the directions shown in FIGS. 1 and 2.
The battery 1 is a rectangular and sealed lithium ion secondary battery mounted on a vehicle such as a hybrid car, a plug-in hybrid car, or an electric car. The battery 1 includes a battery case 10, an electrode body 20 accommodated therein, a positive terminal member 50 and a negative terminal member 60 supported by the battery case 10, and the like. In addition, an electrolytic solution 17 is accommodated in the battery case 10, and a part thereof is impregnated in the electrode body 20. This electrolytic solution 17 is obtained by dissolving LiPF ₆ at a concentration of 1.0 M in a non-aqueous solvent in which ethylene carbonate (EC), dimethyl carbonate (DMC), and ethyl methyl carbonate (EMC) are mixed at a volume ratio of 30:40:30. Non-aqueous electrolyte.

  Among these, the battery case 10 has a rectangular parallelepiped box shape and is made of metal (in this embodiment, aluminum). The battery case 10 is composed of a bottomed rectangular tube-shaped case main body member 11 that is open only on the upper side, and a rectangular plate-shaped case lid member 13 that is welded in a form that closes the opening of the case main body member 11. The Among these, the case lid member 13 is formed with a liquid injection hole 13 h that penetrates the inside and outside of the battery case 10 and is used when the electrolytic solution 17 is injected into the battery case 10 at a predetermined position. The liquid injection hole 13 h is hermetically sealed by welding the sealing member 15 to the case lid member 13.

  Further, a positive terminal member 50 made of aluminum is fixed to the case lid member 13 in a state of being insulated from the case lid member 13. The positive electrode terminal member 50 is connected to the positive electrode plate 21 of the electrode body 20 in the battery case 10 to be conductive, and extends through the case lid member 13 to the outside of the battery. Further, a negative electrode terminal member 60 made of copper is fixed to the case lid member 13 while being insulated from the case lid member 13. The negative electrode terminal member 60 is connected to and conductive with the negative electrode plate 31 of the electrode body 20 in the battery case 10, and extends through the case lid member 13 to the outside of the battery.

  The electrode body 20 is a flat wound electrode body, and is housed in the battery case 10 in a state where the axis is laid sideways. Between the electrode body 20 and the battery case 10, a bag-shaped insulating film enclosure 19 made of an insulating film is disposed. The electrode body 20 includes a belt-like positive electrode plate 21 and a belt-like negative electrode plate 31 that are overlapped with each other via a pair of separators 41 and 41 made of a resin-made porous film and wound around an axis to be flat. Compressed. The positive electrode plate 21 is provided with a positive electrode active material layer made of a positive electrode active material, a conductive material, and a binder in a band shape at predetermined positions on both main surfaces of a positive electrode current collector foil made of a belt-like aluminum foil. The negative electrode plate 31 is provided with a negative electrode active material layer made of a negative electrode active material, a binder, and a thickener in a band shape at predetermined positions on both main surfaces of a negative electrode current collector foil made of a strip-like copper foil.

  Next, a method for manufacturing the battery 1 will be described (see FIGS. 3 and 4). First, in the assembly process of step S1, the battery 1x is assembled. Specifically, the positive electrode plate 21 and the negative electrode plate 31 are overlapped with each other via a pair of separators 41 and 41 and wound into a flat shape to form the electrode body 20. Separately, a case lid member 13 is prepared, and a positive electrode terminal member 50 and a negative electrode terminal member 60 are fixed thereto (see FIGS. 1 and 2). Thereafter, the positive electrode terminal member 50 and the negative electrode terminal member 60 are welded to the positive electrode plate 21 and the negative electrode plate 31 of the electrode body 20, respectively. Next, the electrode body 20 is covered with the insulating film enclosure 19, and these are inserted into the case main body member 11, and the opening of the case main body member 11 is closed with the case lid member 13. Then, the battery case 10 is formed by welding the case body member 11 and the case lid member 13 over the entire circumference of the case lid member 13.

  In the assembly step S1, there may be a case where the battery 1x has an airtight defect portion such as a pinhole or a crack. The hermetic defect portion is particularly likely to occur at a welded portion between the case main body member 11 and the case lid member 13 of the battery case 10 and a fixed portion between the positive electrode terminal member 50 and the negative electrode terminal member 60 and the battery case 10. However, in the present embodiment, as will be described later, since the airtight inspection shown in steps S5 to S11 is performed, the battery 1x in which such an airtight defect portion has occurred can be excluded in the process of manufacturing the battery 1.

Next, the liquid injection process of step S2 is performed about this assembled battery 1x. That is, the electrolytic solution 17 is injected into the battery case 10 through the injection hole 13 h and impregnated in the electrode body 20.
Next, in the gas introduction process of step S3, an inspection gas (helium gas in the embodiment) GS1 is introduced into the battery case 10 through the injection hole 13h.

  Next, in the sealing step in step S4, the battery case 10 is hermetically sealed. That is, the sealing member 15 is welded to the case lid member 13 of the battery case 10 to hermetically seal the liquid injection hole 13h, and the battery case 10 is hermetically sealed. The time from the end of the gas introduction step S3 to the start of the sealing step S4 is preferably as short as possible, for example, within 120 seconds. This is because if the concentration of the helium gas GS1 in the battery case 10 is too low, the airtight inspection described later cannot be performed normally.

  In this sealing step S4, an airtight defect portion such as a pinhole or a crack may be formed at the welded portion between the sealing member 15 and the battery case 10 in some cases. However, in this embodiment, as will be described later, since the airtight inspection shown in Steps S5 to S11 is performed, the battery 1 in which such an airtight defective portion has occurred can be excluded.

  Next, the battery 1 is subjected to an airtight inspection shown in steps S5 to S11. This airtight inspection is performed using the airtight inspection apparatus 100 shown in FIG. The hermeticity inspection apparatus 100 can detect the chamber 110, the vacuum pump 120 that depressurizes the chamber 110, the helium gas detector 130 that can detect the helium gas GS1, and the electrolyte-derived gas GS2 in which the electrolyte 17 is volatilized. And an electrolyte-derived gas detector 140.

  The chamber 110 and the vacuum pump 120 are connected via a gas first flow passage 121. In the middle of the gas first flow passage 121, there are an electromagnetic valve 123 for turning on and off the gas flow in the gas first flow passage 121 and a needle valve 125 for adjusting the flow rate of the gas flowing through the gas first flow passage 121. Arranged

  In this embodiment, a tin oxide semiconductor gas sensor is used as the helium gas detector 130. The helium gas detector 130 is connected to the chamber 110 via a gas first flow path 121 and a gas second flow path 131 branched from the gas first flow path 121. In the middle of the gas second flow path 131, an electromagnetic valve 133 for turning on and off the gas flow in the gas second flow path 131 is disposed.

  In the present embodiment, a tin oxide semiconductor gas sensor is used as the electrolytic solution-derived gas detector 140. The electrolytic solution-derived gas detector 140 can collectively detect volatile components of ethylene carbonate (EC), dimethyl carbonate (DMC), and ethyl methyl carbonate (EMC) constituting the electrolytic solution 17. Note that a combustion-type gas sensor can be used as the electrolyte-derived gas detector 140.

  The electrolyte-derived gas detector 140 is connected to the chamber 110 via a gas first flow passage 121 and a gas third flow passage 141 branched from the gas first flow passage 121. Further, the gas third flow passage 141 is connected to a portion of the gas first flow passage 121 between the electromagnetic valve 123 and the needle valve 125. The portion of the gas third flow passage 141 between the chamber 110 and the electrolyte-derived gas detector 140 has gas in the gas third flow passage 141 between the chamber 110 and the electrolyte-derived gas detector 140. An electromagnetic valve 143 for turning on / off the flow is disposed. Further, in the portion of the gas third flow passage 141 from the electrolyte solution derived gas detector 140 to the gas first flow passage 121, there is a space between the electrolyte solution derived gas detector 140 and the gas first flow passage 121. An electromagnetic valve 145 for turning on / off the gas flow in the gas third flow passage 141 and a needle valve 147 for adjusting the flow rate of the gas are arranged.

In the airtightness inspection apparatus 100, the gas fourth flow passage 151 connected to the outside of the chamber 110 is connected to the chamber 110. In the middle of the fourth gas flow path 151, an electromagnetic valve 153 for turning on and off the gas flow in the fourth gas flow path 151 and a leak valve 155 for adjusting the flow rate of the gas are arranged. In addition, a filter 157 is attached to the distal end of the fourth gas flow passage 151 to prevent foreign matters from entering the fourth gas flow passage 151 from the outside.
Furthermore, a gas fifth flow passage 161 connected to the outside of the chamber 110 is connected to the chamber 110. In the middle of the fifth gas flow passage 161, an electromagnetic valve 163 for turning on and off the gas flow in the fifth gas flow passage 161 is disposed. In addition, a filter 165 is attached to the tip of the fifth gas flow passage 161 to prevent foreign matters from entering the fifth gas flow passage 161 from the outside.

  In performing the airtight inspection of the battery 1 using the airtight inspection device 100, the battery 1 that has finished the sealing step S4 is first housed in the chamber 110. Thereafter, the vacuum pump 120 is operated, and in this state, the electromagnetic valve 123 is opened, the flow rate of the gas flowing through the gas first flow passage 121 is adjusted by the needle valve 125, and the inside of the chamber 110 is depressurized for a predetermined time. The pressure inside 110 is reduced to, for example, a pressure reduction degree of 0 to 20 kPa abs (in this embodiment, a pressure reduction degree of 1 kPa abs or less).

  At this time, if the battery 1 has an airtight portion, the helium gas GS1 and the electrolyte-derived gas GS2 leak from the inside of the battery to the outside of the battery through the airtight portion and stay in the chamber 110. Note that when the electrolyte solution 17 adheres to the poorly sealed portion and the poorly sealed portion is blocked with the electrolyte solution 17, the leakage amount Q1 of the helium gas GS1 is small, and the electrolyte-derived gas GS2 is mainly outside the battery. Leak out.

First, in the inspection gas detection process of step S5, the leak amount Q1 (Pa · m ³ / sec) of the helium gas GS1 leaking from the inside of the battery to the outside of the battery is detected. In this embodiment, after closing the electromagnetic valve 123 arranged in the gas first flow passage 121, the electromagnetic valve 133 arranged in the gas second flow passage 131 is opened. Thereby, the gas in the chamber 110 is sent to the helium gas detector 130 through the gas first flow path 121 and the gas second flow path 131 branched from the middle, and the helium gas detector 130 leaks the helium gas GS1 Q1. (Pa · m ³ / sec) is detected. After measuring the leakage amount Q1 of the helium gas GS1, the electromagnetic valve 133 of the gas second flow path 131 is closed.
The time from the end of the sealing step S4 to the start of the inspection gas detection step S5 is preferably as short as possible, for example, within 30 minutes. This is because if a large amount of helium gas GS1 leaks from the airtight defect portion and the concentration of the helium gas GS1 in the battery case 10 is greatly reduced, the airtight inspection cannot be performed normally.

Next, in step S6, it is determined whether or not the measured leak amount Q1 of the helium gas GS1 is equal to or greater than the first reference leak amount Q1k (Q1 ≧ Q1k). In the present embodiment, the first reference leakage amount Q1k is set to 9.5 × 10 ⁻⁶ Pa · m ³ / sec. The value of the first reference leakage amount Q1k will be described later. If YES in step S6, that is, if the leakage amount Q1 of the helium gas GS1 is greater than or equal to the first reference leakage amount Q1k, the process proceeds to step S7, and the battery 1 is determined to be an airtight defect product. This is because it is considered that the leak amount Q1 of the helium gas GS1 is increased because the battery 1 has an unacceptable size airtight portion. Steps S6 and S7 correspond to the “first step” in the determination step described above.

  On the other hand, if NO in step S6, that is, if the leak amount Q1 of the helium gas GS1 is less than the first reference leak amount Q1k (Q1 <Q1k), the process proceeds to step S8. In this case, the battery 1 does not have an airtight defect portion or has an airtight defect portion. However, since the electrolyte solution 17 adheres to the airtight defect portion, the leakage amount Q1 of the helium gas GS1 is reduced. It is thought that there is.

In the electrolyte solution-derived gas detection step in step S8, the leakage amount Q2 (Pa · m ³ / sec) of the electrolyte solution-derived gas GS2 that leaks from the inside of the battery to the outside of the battery is detected. In the present embodiment, the electromagnetic valve 143 and the electromagnetic valve 145 arranged in the gas third flow passage 141 are opened. As a result, the gas in the chamber 110 is sent to the electrolyte-derived gas detector 140 through the gas first flow passage 121 and the gas third flow passage 141 branched from the middle, and the electrolyte-derived gas detector 140 derives the electrolyte. The leakage amount Q2 (Pa · m ³ / sec) of the gas GS2 is detected. After measuring the leakage amount Q2 of the electrolyte-derived gas GS2, the electromagnetic valve 143 and the electromagnetic valve 145 disposed in the gas third flow passage 141 are closed.

  In addition, the detection sensitivity of the electrolyte-derived gas detector 140 can be improved by adjusting the flow rate of the gas in the gas third flow passage 141 with the needle valve 147 within a range of, for example, 5 to 1000 mL / min. Further, the electromagnetic valve 153 disposed in the gas fourth flow passage 151 connected to the chamber 110 is opened and the flow rate of the gas flowing through the gas fourth flow passage 151 is adjusted by the leak valve 155, so that the electrolyte-derived gas GS2 is contained in the chamber. It can suppress staying in 110, and can distribute electrolyte solution origin gas GS2 to electrolyte solution origin gas detector 140 certainly.

Next, in step S9, the absolute value ΔQ = | Q1−Q2 | of the difference in leak amount between the measured leak amount Q1 of the helium gas GS1 and the leak amount Q2 of the electrolyte-derived gas GS2 is equal to or greater than the reference difference ΔQk ( It is determined whether or not | Q1−Q2 | ≧ ΔQk). In this embodiment, the reference difference ΔQk = 1.0 × 10 ⁻⁵ Pa · m ³ / sec. The value of this reference difference ΔQk will be described later.

If YES in step S9, that is, if the absolute value ΔQ = | Q1-Q2 | of the difference in leakage amount is greater than or equal to the reference difference ΔQk, the process proceeds to step S10 described later. In this case, there is a possibility that the electrolytic solution 17 adheres to the airtight portion.
On the other hand, if NO, that is, if the absolute value ΔQ = | Q1-Q2 | of the difference in leakage amount is less than the reference difference ΔQk (| Q1-Q2 | <ΔQk), the process proceeds to step S11 and the battery 1 is airtight. A non-defective product with no defective part (more precisely, a battery that can be handled as a non-defective part with little influence on the battery performance because the hermetic defective part is not present at all or is very small) . In this case, the electrolyte solution 17 does not adhere to the airtight defective portion, and the airtight defective product has already been determined as the airtight defective product in Step S6 and Step S7 described above. Steps S9 and S11 correspond to the “second step” of the above-described determination step.

Next, if YES is determined in step S9 and the process proceeds to step S10, whether or not the leakage amount Q2 of the electrolyte-derived gas GS2 is equal to or greater than the second reference leakage amount Q2k (Q2 ≧ Q2k) in step S10. Determine whether. The second reference leakage amount Q2k is equal to or less than the first reference leakage amount Q1k (= 9.5 × 10 ⁻⁶ Pa · m ³ / sec) (Q2k = 8.5 × 10 ^{− in} this embodiment). ⁶ Pa · m ³ / sec). The value of the second reference leakage amount Q2k will be described later.

If YES, that is, if the leakage amount Q2 of the electrolyte-derived gas GS2 is equal to or greater than the second reference leakage amount Q2k, the process proceeds to step S7 described above, and the battery 1 is determined to be an airtight defect. This is because it is considered that the leakage amount Q2 of the electrolyte solution-derived gas GS2 is increased because the battery 1 has an unacceptably small airtight portion.
On the other hand, if NO in step S10, that is, if the leakage amount Q2 of the electrolyte-derived gas GS2 is less than the second reference leakage amount Q2k (Q2 <Q2k), the process proceeds to step S11, and the battery 1 is removed from the airtight portion. It is determined that there is no good product. This is because the leakage amount Q2 of the electrolyte-derived gas GS2 is small, and it is considered that there is no airtight defect portion having an unacceptable size in the battery 1. In addition, these step S10, step S7, and step S11 correspond to the "3rd process" of the above-mentioned determination process.

  Thus, the airtight inspection is completed. Note that Step S6, Step S7, and Step S9 to Step S11 correspond to the aforementioned “determination step”. Thereafter, the electromagnetic valve 163 disposed in the gas fifth flow passage 161 connected to the chamber 110 is opened to open the chamber 110 to the atmosphere. Then, the battery 1 is taken out from the chamber 110, and the battery 1 determined to be an airtight product is removed. Thus, the battery 1 is completed.

Here, the first reference leakage amount Q1k (= 9.5 × 10 ⁻⁶ Pa · m ³ / sec) and the second reference leakage amount Q2k (= 8.5 × 10 ⁻⁶ Pa · m ³ / sec) are described. Each value of the reference difference ΔQk (= 1.0 × 10 ⁻⁵ Pa · m ³ / sec) will be described (see FIG. 5). The graph of FIG. 5 shows the leak amount Q1 of helium gas GS1 and the electrolyte derived from a test battery (a specific battery 1 having a minute airtight defect portion of a predetermined size) that is a criterion for determining whether airtightness is good or bad. This is a result obtained by repeatedly measuring the leakage amount Q2 of the gas GS2.

The amount of leakage Q1 of the measured helium gas GS1 differs between the case where the electrolyte solution 17 is not attached to the poorly sealed portion and the case where the electrolyte solution 17 is attached to the poorly sealed portion. Specifically, when the electrolyte solution 17 does not adhere to the poorly sealed portion, the measured value of the leakage amount Q1 of the helium gas GS1 is P1 = 1.0 × 10 ⁻⁵ Pa · m ³ / sec. It becomes a value within the range of ~ P2 = 2.0 × 10 ⁻⁵ Pa · m ³ / sec. Therefore, the first reference leakage amount Q1k is a value lower than P1 = 1.0 × 10 ⁻⁵ Pa · m ³ / sec. In this embodiment, Q1k = 9.5 × 10 ⁻⁶ Pa · m ³ / sec. It was.
On the other hand, when the electrolyte solution 17 is attached to the poorly sealed portion, the measured value of the leakage amount Q1 of the helium gas GS1 is P3 = 6 × 10 ⁻⁸ Pa · m ^{3 /} sec to P4 = 1.0 × 10 ^−. The value is within the range of ⁷ Pa · m ³ / sec.

On the other hand, the measured value of the leakage amount Q2 of the electrolyte-derived gas GS2 is P5 = 9.0 × 10 ⁻⁶ Pa · m ³ / sec to P6 =, regardless of whether or not the electrolyte 17 adheres to the airtight portion. The value is in the range of 2.2 × 10 ⁻⁵ Pa · m ³ / sec. Therefore, the second reference leakage amount Q2k is a value lower than P5 = 9.0 × 10 ⁻⁶ Pa · m ³ / sec. In the present embodiment, Q2k = 8.5 × 10 ⁻⁶ Pa · m ³ / sec. It was.

Thus, in this embodiment, the measured value variation of the leakage amount Q2 of the electrolyte-derived gas GS2 becomes larger than the measured value variation of the leakage amount Q1 of the helium gas GS1. Since the measured value variation of the leak amount Q1 of the helium gas GS1 is small, the first reference leak amount Q1k can be set to a larger value (in this embodiment, 9.5 × 10 ⁻⁶ Pa · m ³ / sec), Since the measured value variation of the leakage amount Q2 of the electrolyte-derived gas GS2 is large, the second reference leakage amount Q2k is set to a smaller value (8.5 × 10 ⁻⁶ Pa · m ³ / sec in this embodiment). ing. In this way, by using the first reference leakage amount Q1k and the second reference leakage amount Q2k having different values in consideration of variations in the measured values of the leakage amounts Q1 and Q2, overdetermined in step S6 and step S10 (non-defective products are airtight) The number of batteries determined to be defective can be suppressed.

When the electrolyte solution 17 does not adhere to the airtight portion, the measured value of the leakage amount Q1 of the helium gas GS1 is P2 = 2.0 × 10 ⁻⁵ Pa · m ³ / sec at the maximum, and the electrolyte-derived gas The minimum measured value of the leakage amount Q2 of GS2 is P5 = 9.0 × 10 ⁻⁶ Pa · m ³ / sec. The absolute value ΔPA of these differences is ΔPA = | P2-P5 | = 1.1 × 10 ⁻⁵ Pa · m ³ / sec. Therefore, when the electrolytic solution 17 does not adhere to the poorly sealed portion, the absolute value ΔQ = | Q1-Q2 of the difference between the measured leakage amount Q1 of the helium gas GS1 and the leakage amount Q2 of the electrolytic solution-derived gas GS2. | Becomes ΔPA = 1.1 × 10 ⁻⁵ Pa · m ³ / sec or less.

On the other hand, when the electrolytic solution 17 adheres to the poorly sealed portion, the measured value of the leakage amount Q1 of the helium gas GS1 is P4 = 1.0 × 10 ⁻⁷ Pa · m ³ / sec at the maximum. The measured value of the leak amount Q2 of the source gas GS2 is at least P5 = 9.0 × 10 ⁻⁶ Pa · m ³ / sec. The absolute value ΔPB of these differences is ΔPB = | P4-P5 | = 8.9 × 10 ⁻⁶ Pa · m ³ / sec. Accordingly, when the electrolytic solution 17 is attached to the poorly sealed portion, the absolute value ΔQ = | Q1-Q2 of the difference between the measured leakage amount Q1 of the helium gas GS1 and the leakage amount Q2 of the electrolytic solution-derived gas GS2. | Becomes ΔPB = 8.9 × 10 ⁻⁶ Pa · m ³ / sec or more.

The reference difference ΔQk is set between ΔPA = 1.1 × 10 ⁻⁵ Pa · m ³ / sec and ΔPB = 8.9 × 10 ⁻⁶ Pa · m ³ / sec. For example, as described above, the reference difference ΔQk = 1.0 × 10 ⁻⁵ Pa · m ³ / sec is set.
Thereby, in step S9, when the absolute value ΔQ = | Q1-Q2 | of the difference in leakage amount is equal to or larger than the reference difference ΔQk, there is a possibility that the electrolyte solution 17 is attached to the airtight defective portion. In step S10, the airtightness of the battery 1 is determined based on the amount of leakage Q2 of the electrolyte-derived gas GS2.

  On the other hand, if the absolute value ΔQ = | Q1−Q2 | of the difference in leakage amount is less than the reference difference ΔQk, the electrolytic solution 17 is not attached to the airtight defect portion, so the process proceeds to step S11, and the battery 1 can be determined as a non-defective product without airtight defects. This is because the determination in step S6 is sufficient for the battery 1 in which the electrolyte solution 17 does not adhere to the airtight portion, so that the determination in step S10 is not necessary.

As described above, in the manufacturing method of the battery 1, after the sealing step S4, the leakage amount Q1 of the helium gas GS1 is detected and the leakage amount Q2 of the electrolyte-derived gas GS2 is detected.
In an airtight product battery in which an airtight defective portion has occurred, when the electrolyte solution 17 adheres to the airtight defective portion, the helium gas GS1 is difficult to leak from the inside of the battery to the outside of the battery through the airtight defective portion. Compared with the case where the electrolytic solution 17 is not attached to the defective portion, the leakage amount Q1 of the helium gas GS1 detected in the inspection gas detection step S5 is reduced.

On the other hand, regarding the electrolyte-derived gas GS2, the electrolyte-derived gas GS2 leaks from the inside of the battery to the outside of the battery through the poorly sealed portion regardless of whether or not the electrolytic solution adheres to the poorly sealed portion. The leakage amount Q2 of the electrolyte-derived gas GS2 detected in the detection step S8 is not so different.
Therefore, the airtightness of the battery 1 is determined based on both the leakage amount Q1 of the helium gas GS1 and the leakage amount Q2 of the electrolyte-derived gas GS2 in steps S6, S7, and S9 to S11 corresponding to the determination process. By doing so, the airtightness of the battery 1 can be appropriately determined irrespective of the presence or absence of the electrolyte solution 17 adhering to the airtight defective portion. Therefore, according to the manufacturing method of the battery 1, the hermeticity of the battery 1 can be inspected appropriately, and the sealed battery 1 with high hermetic reliability can be manufactured.

In the present embodiment, the measurement accuracy of the helium gas detector 130 that detects the leak amount Q1 of the helium gas GS1 is higher than the measurement accuracy of the electrolyte solution-derived gas detector 140 that detects the leak amount Q2 of the electrolyte solution-derived gas GS2. .
When the airtightness of the battery 1 is determined based on the amount of leakage Q2 of the electrolyte-derived gas GS2 in step S10, if the value of the second reference leakage amount Q2k is too large, an airtight defective product is erroneously determined as a good product. More cases. Therefore, it is conceivable that the value of the second reference leakage amount Q2k of the electrolyte-derived gas GS2 is set to a value that is small enough to prevent erroneous determination. However, in this case, the number of batteries over-determined that the non-defective product is overly airtight increases, and the yield of the battery 1 decreases.

  On the other hand, in the manufacturing method of the battery 1, prior to determining the airtightness of the battery 1 based on the amount of leakage Q2 of the electrolyte-derived gas GS2 in step S10, the leakage of the helium gas GS1 in step S9. When the difference (| Q1-Q2 |) between the amount Q1 and the leakage amount Q2 of the electrolyte-derived gas is less than the reference difference ΔQk (| Q1-Q2 | <ΔQk), the battery 1 is determined to be a good product. . Only in the case where the difference (| Q1-Q2 |) is determined to be greater than or equal to the reference difference ΔQk (| Q1-Q2 | ≧ ΔQk) in step S9, the process proceeds to step S10.

  In the manufacturing method of the battery 1, since some of the batteries 1 are determined to be non-defective products in step S 9 and step S 11 and step S 10 is not performed, the battery 1 determined to be non-defective in step S 9 and step S 11 is obtained. Further, it is possible to reduce the case where it is over-determined that the product is not airtight in step S10 and step S7. Therefore, according to the manufacturing method of the battery 1, it is possible to reduce the number of non-defective batteries that are over-determined to be airtight defects in Step S <b> 10 and Step S <b> 7, and to improve the yield of the battery 1.

In the above, the present invention has been described with reference to the embodiment. However, the present invention is not limited to the above-described embodiment, and it is needless to say that the present invention can be appropriately modified and applied without departing from the gist thereof.
For example, in the embodiment, the battery 1 in which the liquid injection hole 13h is hermetically sealed by welding the sealing member 15 to the case lid member 13 is illustrated, but the sealing form of the liquid injection hole is not limited thereto. . For example, a battery in which a female screw is formed in the liquid injection hole and a bolt is screwed into the liquid injection hole to hermetically seal the liquid injection hole, or a blind rivet is inserted into the liquid injection hole to inject the liquid injection hole The present invention can also be applied to a battery that is hermetically sealed.

Further, in the embodiment, in the assembling step S <b> 1, it occurs in a welded portion between the case main body member 11 and the case lid member 13 of the battery case 10, a fixed portion between the positive terminal member 50 and the negative terminal member 60 and the battery case 10, or the like. The case where the airtight failure and the airtight failure occurring in the welded portion between the sealing member 15 and the battery case 10 in the sealing step S4 are inspected by the airtight inspection in steps S5 to S11 is illustrated, but the present invention is not limited thereto. Absent.
For example, after the assembly process S1 and before the liquid injection process S2, the airtight defect that occurs in the assembly process S1 is separately inspected, and in the airtight inspection in steps S5 to S11, only the airtight defect that occurs in the sealing process S4 is inspected. You can also. In this case, it is not necessary to dispose the entire battery 1 under reduced pressure. For example, by applying a vacuum pad so as to cover the sealing member 15, an airtight defect occurring at the welded portion between the sealing member 15 and the battery case 10 is inspected. You can also

  In the embodiment, the leakage amount Q1 of the helium gas GS1 is first measured in step S5, and the leakage amount Q2 of the electrolyte-derived gas GS2 is measured later in step S8, but the electrolyte-derived gas GS2 is first measured. The leakage amount Q2 of the helium gas GS1 may be measured after that.

1 battery (sealed battery)
1x battery (before liquid injection process) (sealed battery)
10 Battery Case 13h Injection Hole 15 Sealing Member 17 Electrolyte GS1 Helium Gas (Inspection Gas)
GS2 Electrolyte-derived gas S1 Assembly process S2 Injection process S3 Gas introduction process S4 Sealing process S5 Inspection gas detection process S8 Electrolyte-derived gas detection processes S6, S7, S9 to S11 Determination process 100 Airtightness inspection apparatus 110 Chamber 130 Helium Gas detector 140 Electrolyte-derived gas detector Q1 (Helium gas) leak amount Q1k First reference leak amount Q2 (Electrolyte-derived gas) leak amount Q2k Second reference leak amount

Claims (1)

A method of manufacturing a sealed battery,
An injection process for injecting an electrolyte into the battery case;
A gas introduction step for introducing an inspection gas into the battery case;
After the liquid injection step and the gas introduction step, a sealing step for hermetically sealing the battery case;
After the sealing step, an inspection gas detection step of detecting the leakage amount Q1 of the inspection gas leaking from the inside of the battery to the outside of the battery;
After the sealing step, an electrolyte-derived gas detection step for detecting the leak amount Q2 of the electrolyte-derived gas from which the electrolyte has volatilized leaks from the inside of the battery,
A determination step of determining the airtightness of the sealed battery based on the leakage amount Q1 of the inspection gas and the leakage amount Q2 of the electrolyte-derived gas,
The determination process is as follows:
A first step of determining that the sealed battery is an airtight product when the inspection gas leakage amount Q1 is equal to or greater than the first reference leakage amount Q1k (Q1 ≧ Q1k);
The difference (| Q1-Q2 |) between the leak amount Q1 of the inspection gas and the leak amount Q2 of the electrolyte-derived gas is the reference difference for the sealed battery that is not determined to be an airtight product in the first step. A second step of determining that the sealed battery is a non-defective product having good airtightness when it is less than ΔQk (| Q1-Q2 | <ΔQk);
For the sealed battery in which the difference (| Q1-Q2 |) is determined to be greater than or equal to the reference difference ΔQk (| Q1-Q2 | ≧ ΔQk) in the second step, the leakage amount Q2 of the electrolyte-derived gas is When it is equal to or greater than the second reference leakage amount Q2k (Q2k ≦ Q1k) set to a value equal to or less than the first reference leakage amount Q1k (Q2 ≧ Q2k), the sealed battery is determined to be an airtight defect, and the leakage amount And a third step of determining the sealed battery as the non-defective product when Q2 is less than the second reference leakage amount Q2k (Q2 <Q2k).

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