JP2011192523A - Manufacturing method and degassing device of secondary battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method and a degassing device of a secondary battery having a gas discharging process that can not only discharge a gas generated in a battery container by initial charge/discharge but also determine the battery state by measuring the amount of the gas generated at that time. <P>SOLUTION: The gas is discharged out of a battery 100 after the initial charge/discharge is carried out. A degassing device 300 is used for this purpose. The degassing device 300 has a hollow needle 310, a pressure sensor 340, an open valve 350, and a discharge port 372. While the condition of the open valve 350 is closed, the hollow needle 310 is inserted into a hole opening part 104 of the battery 100. When the pressure inside the degassing device 300 becomes nearly equal to the pressure inside the battery 100, the pressure sensor 340 measures the pressure. The battery state is determined by the value of the pressure. After the pressure is measured, the open valve 350 is kept open to discharge the inside gas from the discharge port 372 of the battery 100. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a secondary battery and a gas venting device. More specifically, the present invention relates to a method for manufacturing a secondary battery and a gas venting device having a gas venting process for venting a gas generated during initial charge / discharge.

  Secondary batteries are used in various fields such as electronic devices such as mobile phones and personal computers, vehicles such as hybrid vehicles and electric vehicles. Such a secondary battery includes a positive electrode plate, a negative electrode plate, and an electrolyte. Moreover, it is common to use the electrode body which laminated | stacked the positive electrode plate, the negative electrode plate, and the separator which insulates them.

  Some of these secondary batteries have an electrode body disposed in a battery container and an electrolyte solution is injected therein. In such an electrolyte type secondary battery, gas may be generated inside during initial charge and discharge. In such a method of manufacturing a secondary battery, a degassing step of extracting gas inside the battery container generated by the initial charge / discharge may be performed.

  For example, in a manufacturing process of a lithium ion secondary battery, initial charging / discharging is performed after temporarily injecting a liquid injection port. The main sealing is performed after degassing the gas generated by the initial charge / discharge (see paragraph [0086] of Patent Document 1). The gas generated by this initial charge / discharge is mainly hydrogen gas generated by the reduction reaction of water bonded to the positive electrode plate or the negative electrode plate (see paragraph [0087] of Patent Document 1).

  If gas is still generated inside the battery container, the pressure inside the battery container is high. And the greater the amount of gas generated, the higher the pressure inside the battery container. When the internal pressure of the battery container increases, the battery container may be deformed. And if the deformation of the battery container is large, there arises a problem that it cannot be mounted on equipment or vehicles.

  For this reason, techniques for reducing the pressure inside the battery container have been developed. Patent Document 2 discloses a technique for extracting gas from the inside of a battery container using a gas venting device having a hollow needle in a battery that has been initially charged (see paragraphs [0018] to [ 0020] and FIG. Patent Document 3 also discloses a technique for extracting gas from the inside of a battery container after initial charging (see paragraphs [0018] and [0038] and FIG. 3 of Patent Document 3). In these documents, it is said that the internal pressure can be lowered by removing the gas inside the battery.

JP 2007-227310 A JP 2000-353547 A JP 2005-222757 A

  By the way, in the lithium ion secondary battery, the performance of the battery having a high moisture content of the composite layer of the positive electrode plate or the negative electrode plate is low. Here, the composite material layer is a layer made of a composite material containing a positive electrode active material or a negative electrode active material. The water in the positive electrode plate or the composite layer of the negative electrode plate may directly react with lithium ions in the electrolyte. As the lithium ions react, the concentration of lithium ions in the electrolyte decreases. This is because lithium ions are used in the reaction to form another compound. Also, if there is moisture, highly reactive substances such as lithium nitride and lithium oxide may be generated. On the other hand, the moisture in the positive electrode plate or the composite layer of the negative electrode plate may react with the electrolytic solution to decompose the electrolytic solution. In addition, as described above, hydrogen gas may be generated during initial charge / discharge.

  The higher the moisture content of the positive electrode plate or the negative electrode plate composite layer, the greater the amount of gas generated during initial charge / discharge. In a battery with a large amount of gas generation, as described above, when the concentration of lithium ions in the electrolyte is low, when a highly reactive substance is generated inside the battery, or when the amount of decomposition of the electrolyte is large There is. That is, the performance of a battery with a large amount of gas generation is low. However, the techniques disclosed in Patent Documents 1 to 3 cannot measure the amount of gas generated inside the battery. In other words, the quality of the secondary battery cannot be determined based on the measured gas generation amount.

  The present invention has been made to solve the above-described problems of the prior art. In other words, the problem is that the gas generated in the battery container due to the initial charge / discharge is vented, and the amount of gas generated at that time is measured to determine whether the battery is good or bad. It is providing the manufacturing method and degassing apparatus of a secondary battery which have a process.

  In order to solve this problem, the method for manufacturing a secondary battery according to the present invention includes inserting an electrode body in which a positive and negative electrode plate and a separator for insulating them are stacked into a battery case and placing the electrode body inside the battery case. A battery assembly process for injecting an electrolyte, an initial charge / discharge process in which the battery case is sealed once after the battery assembly process, and a gas inside the battery case is removed from the battery case after the initial charge / discharge process. It is a manufacturing method of a secondary battery which has a degassing process and a sealing process of sealing a battery case after the degassing process. The degassing process includes a state measurement process for measuring a state value indicating the amount of gas generated in the battery case in the initial charge / discharge process, and a state value measured in the state measurement process is greater than a predetermined threshold value. In addition, when the secondary battery is determined to be defective and the state value measured in the state measurement step is a value equal to or less than a predetermined threshold, the pass / fail determination step is performed to determine that the secondary battery is non-defective. And at least a gas discharge step of discharging the gas inside the battery case in the secondary battery determined to be non-defective in the pass / fail determination step to the outside of the battery case. In such a secondary battery manufacturing method, the quality of the secondary battery can be determined based on the measured state value. Moreover, the moisture content of the electrode plate of the secondary battery manufactured by this manufacturing method is low.

  In the secondary battery manufacturing method described above, in the degassing step, the pressure inside the battery case may be used as the state value. This is because the quality of the manufactured secondary battery can be determined.

  In the method for manufacturing a secondary battery described above, in the gas venting process, the accumulated flow rate of the gas flowing out from the inside of the battery case in the gas discharging process may be used as the state value. This is because the quality of the manufactured secondary battery can be determined.

  In the secondary battery manufacturing method described above, the time from the end time of the battery assembly process to the start time of the sealing process may be set in advance as a set time, and the threshold value may be corrected according to the set time. This is because a more suitable value can be used as the threshold value used for the pass / fail judgment.

  In the method for manufacturing a secondary battery described above, at least a first set time, a first threshold value corresponding thereto, a second set time longer than the first set time, and a second threshold value corresponding thereto. More preferably, the first threshold value is smaller than the second threshold value. This is because a more suitable value can be used as the threshold value used for the pass / fail judgment.

  In the method for manufacturing a secondary battery as described above, a high-temperature holding treatment step is held after the sealing step at a temperature of 40 ° C. to 65 ° C. for at least 6 hours, from the end time of the initial charge / discharge step. The time until the start time of the process is set in advance as the process setting time, and the threshold value is corrected according to the process setting time. This is because a more suitable value can be used as the threshold value used for the pass / fail judgment.

  In the method of manufacturing a secondary battery described above, at least a first process setting time, a first threshold value corresponding thereto, a second process setting time longer than the first process setting time, and a second time corresponding thereto. It is even better if the first threshold value is larger than the second threshold value. This is because a more suitable value can be used as the threshold value used for the pass / fail judgment.

  The degassing device according to the present invention includes an open tip inserted into an object containing gas, a hollow needle whose inside is hollow, a communication portion communicating with the hollow needle, In a degassing apparatus having an exhaust port that communicates with a communication unit and exhausts gas from the communication unit, and an on-off valve that switches whether the hollow needle and the exhaust port communicate with each other. It has a state measurement part which measures the state value which shows quantity. Such a degassing apparatus can determine whether or not an object is good by extracting gas from an object containing gas and measuring a state value.

  In the gas venting device described above, the state value may be a pressure value of gas flowing from the object into the communication portion via the hollow needle. This is because the quality determination can be made based on the pressure of the gas built into the object.

  In the gas venting device described above, the state value is the value of the gas that has flowed into the gas venting device after the hollow needle is inserted into the object until the inflow to the hollow needle stops with the open / close valve opened. It should be a flow rate. This is because the quality determination can be performed based on the flow rate of the gas contained in the object flowing into the degassing device.

  According to the present invention, there is provided a degassing step of degassing the gas generated in the battery container by the initial charge / discharge and determining the quality of the battery by measuring the amount of gas generated at that time. A secondary battery manufacturing method and a gas venting device are provided.

It is sectional drawing for demonstrating the battery manufactured by the manufacturing method of the secondary battery which concerns on this invention. It is a perspective view for demonstrating the winding electrode body of the battery manufactured by the manufacturing method of the secondary battery which concerns on this invention. It is an expanded view for demonstrating the winding structure of the winding electrode body of the battery manufactured by the manufacturing method of the secondary battery which concerns on this invention. It is a cross-sectional perspective view for demonstrating the structure of the positive electrode plate or negative electrode plate of the battery manufactured by the manufacturing method of the secondary battery which concerns on this invention. It is a fragmentary sectional view for demonstrating the structure of the degassing apparatus which concerns on this invention. It is a schematic diagram for demonstrating the degassing process of the battery manufactured by the manufacturing method of the secondary battery which concerns on this invention. It is a graph which shows the measured value of the internal pressure of the battery produced in various environments.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments embodying the present invention will be described below in detail with reference to the accompanying drawings. In the present embodiment, the present invention is embodied in a method for manufacturing a nonaqueous electrolyte lithium ion secondary battery and a gas venting device.

(First embodiment)
1. Lithium ion secondary battery The battery according to the present embodiment is a cylindrical lithium ion secondary battery. FIG. 1 shows a cross-sectional view of the battery 100 of this embodiment. As shown in FIG. 1, the battery 100 is sealed by a battery case including a battery container 101 and a lid 102. The battery 100 includes a wound electrode body 200, a positive current collector 110, and a negative current collector 120. In addition, an electrolytic solution is injected into the battery container 101.

  The wound electrode body 200 repeatedly charges and discharges in the electrolytic solution and directly contributes to power generation. The positive electrode current collector plate 110 is a positive electrode current collector connected to a positive electrode core material of a wound electrode body 200 described later. The material is aluminum. The negative electrode current collector plate 120 is a negative electrode current collector connected to a negative electrode core material of a wound electrode body 200 described later. Its material is copper. FIG. 2 shows a perspective view of the wound electrode body 200 in which the positive electrode current collector plate 110 and the negative electrode current collector plate 120 are connected from FIG.

The electrolyte injected into the battery container 101 is obtained by dissolving an electrolyte in an organic solvent. Examples of organic solvents include ester solvents such as propylene carbonate (PC), ethylene carbonate (EC), dimethyl carbonate (DMC), and ethyl methyl carbonate (EMC), ester solvents such as γ-butylactone (γ-BL), di- An organic solvent containing an ether solvent such as ethoxyethane (DEE) can be used. As the electrolyte salt, lithium salts such as lithium perchlorate (LiClO ₄ ), lithium borofluoride (LiBF ₄ ), and lithium hexafluorophosphate (LiPF ₆ ) can be used.

2. FIG. 3 is a development view showing a wound structure of the wound electrode body 200. As shown in FIG. 3, the wound electrode body 200 is obtained by winding the positive electrode plate P, the separator S, the negative electrode plate N, and the separator T in this order from the inside. Here, the separator S and the separator T are made of the same material. For the understanding of the above winding order, only the codes are distinguished as S and T.

The positive electrode plate is obtained by applying a mixture containing a positive electrode active material capable of occluding and releasing lithium ions to an aluminum foil as a positive electrode core material. As the positive electrode active material, lithium composite oxides such as lithium nickelate (LiNiO ₂ ), lithium manganate (LiMnO ₂ ), and lithium cobaltate (LiCoO ₂ ) are used. The negative electrode plate is obtained by applying a composite material containing a negative electrode active material capable of occluding and releasing lithium ions to a copper foil as a negative electrode core material. As the negative electrode active material, carbon-based materials such as amorphous carbon, non-graphitizable carbon, graphitizable carbon, and graphite are used.

  As shown in FIG. 3, the positive electrode plate P has a positive electrode coating portion P1 and a positive electrode non-coating portion P2. The positive electrode coating part P1 is a place where a positive electrode active material or the like is applied to the positive electrode core material. The positive electrode non-coating portion P2 is a portion where a positive electrode active material or the like is not applied to the positive electrode core material. Therefore, the thickness of the positive electrode coating part P1 is thicker than the thickness of the positive electrode non-coating part P2.

  The negative electrode plate N includes a negative electrode coating portion N1 and a negative electrode non-coating portion N2. The negative electrode coating portion N1 is a portion where a negative electrode active material or the like is applied to the negative electrode core material. The negative electrode non-coating portion N2 is a portion where a negative electrode active material or the like is not applied to the negative electrode core material. Therefore, the thickness of the negative electrode coating part N1 is thicker than the thickness of the negative electrode non-coating part N2.

  An arrow A in FIG. 3 indicates the width direction (vertical direction in FIG. 1) of the positive electrode plate P, the negative electrode plate N, and the separators S and T. An arrow B in FIG. 3 indicates the longitudinal direction of the positive electrode plate P, the negative electrode plate N, and the separators S and T (the circumferential direction of the wound electrode body 200 in FIG. 1). The coating width in the width direction of the positive electrode coating portion P1 is slightly narrower than the coating width in the width direction of the negative electrode coating portion N1. This is because when the concentration of lithium ions in the electrolytic solution is high, the negative electrode active material occludes lithium ions to suppress an increase in the concentration. If the concentration of lithium ions in the electrolyte solution increases too much, lithium may be deposited in a dendritic form. When such precipitation occurs, the battery performance decreases.

  FIG. 4 is a perspective sectional view of the positive electrode plate P (or the negative electrode plate N). In FIG. 4, each symbol outside the parentheses indicates each part in the case of the positive electrode, and each symbol in the parenthesis indicates each part in the case of the negative electrode. The direction indicated by arrow A in FIG. 4 is the same as the direction indicated by arrow A in FIG. That is, it is the width direction of the positive electrode plate P. The direction indicated by arrow B in FIG. 4 is the same as the direction indicated by arrow B in FIG. That is, it is the longitudinal direction of the positive electrode plate P.

  As shown in FIG. 4, the positive electrode plate P is obtained by forming a positive electrode mixture layer PA on a part of both surfaces of a strip-like positive electrode core material PB. On the left side in FIG. 4, a positive electrode non-coated portion P2 of the positive electrode plate P protrudes in the width direction. The positive electrode non-coated portion P2 is formed in a strip shape. The positive electrode non-coated portion P2 is a region where the positive electrode active material is not applied to both surfaces of the positive electrode core material PB. Therefore, in the positive electrode non-coating portion P2, the positive electrode core material PB is still exposed. On the other hand, on the right side in FIG. 4, there is no protrusion corresponding to the positive electrode non-coated portion P2. In the positive electrode coating part P1, the positive electrode mixture layer PA is formed with a uniform thickness on both surfaces of the positive electrode core material PB.

  As shown in FIG. 4, the negative electrode plate N is obtained by forming a negative electrode mixture layer NA on a part of both surfaces of a strip-shaped negative electrode core material NB. Similarly to the positive electrode, there are a negative electrode coating portion N1 and a negative electrode non-coating portion N2. However, as shown in FIG. 3, at the time of winding, the positive electrode non-coated portion P2 and the negative electrode non-coated portion N2 are wound in a state of protruding to the opposite side.

3. Degassing Device Here, the degassing device used in the method for manufacturing battery 100 according to the present embodiment will be described. FIG. 5 is a partial cross-sectional view showing a gas venting apparatus 300 according to the present embodiment. The gas venting device 300 includes a pressure sensor 340. The degassing device 300 is for measuring the pressure of the gas inside the temporarily sealed battery container 101 and discharging a part of the gas to the outside of the battery container 101. The pressure is a state value indicating the amount of gas built in the battery 100.

  As shown in FIG. 5, in addition to the pressure sensor 340, the gas venting device 300 includes a hollow needle 310, a sealing member 320, a connecting portion 330, a release valve 350, a connecting portion 360, an exhaust portion 370, have.

  The hollow needle 310 is a needle having a hollow portion 312 formed therein. Its shape is cylindrical. The inner diameter is about 0.6 mm, and the outer diameter is about 1 mm. Further, the hollow needle 310 is a ventilation portion that is inserted into the temporary sealing member 103 (see FIG. 6) of the battery 100 and vents the gas inside the battery 100. And the material is stainless steel. Or other metals may be sufficient. These values such as the inner diameter are only a guide, and hollow needles having other inner and outer diameters may be used.

  The tip of the hollow needle 310 is an open tip 311. The inner diameter of the opening is about 0.6 mm. The tip portion 311 is a portion that actually enters the inside of the battery 100 when the hollow needle 310 is inserted into the temporary sealing member 103 of the battery 100. Note that the tip portion 311 slightly protrudes from a sealing surface 321 described later.

  The sealing member 320 is for preventing gas from leaking from the gap between the hollow needle 310 and the temporary sealing member 103 when the hollow needle 310 is inserted into the temporary sealing member 103. The sealing member 320 covers the hollow needle 310 and has a shape opened only around the tip 311 of the hollow needle 310. The sealing surface 321 is perpendicular to the hollow needle 310. The sealing surface 321 is a surface that is in close contact with the temporary sealing member 103 so that gas does not leak to the outside during inhalation by the hollow needle 310.

  The sealing member 320 is pressed in a direction perpendicular to the sealing surface 321, that is, in the direction of arrow C in FIG. 5 when the hollow needle 310 is inserted into the temporary sealing member 103. By this pressing, the sealing member 320 can be deformed. Therefore, for example, urethane rubber may be used as the material of the sealing member 320. However, the type of rubber is not limited as long as it can hold the sealed state when the sealing surface 321 is pressed against the temporary sealing member 103. Other elastic bodies may also be used.

  The connection part 330 is a member for sending the gas flowing in from the hollow needle 310 to the position of the pressure sensor 340. For that purpose, the inside is a hollow portion 331 that communicates with the pressure sensor 340. Note that an O-ring 332 is disposed between the connecting portion 330 and the hollow needle 310 to seal the gap therebetween.

  The pressure sensor 340 is a state measuring unit for measuring the pressure of the gas around the pressure sensor 340. At least when the pressure sensor 340 measures the pressure, the space in the range from the position of the pressure sensor 340 to the hollow portion 331, the hollow portion 312 and the inside of the battery container 101 of the battery 100 is in communication with the outside. Gas is not leaked in the air. That is, it is in a sealed state at the time of measurement.

  The connecting part 360 is disposed between the connecting part 330 and the release valve 350. The connecting part 360 has a hollow part 361. The hollow part 361 communicates with the hollow part 331. The volume of the hollow space of the hollow portion 361 is smaller than the volume of the hollow space of the hollow portion 331.

  The total volume of the hollow portion 312, the hollow portion 331, and the hollow portion 361 is sufficiently smaller than the volume of the space (dead space) that is not occupied by the wound electrode body 320 and the electrolytic solution inside the battery container 101. This is because the pressure inside the battery container 101 is hardly changed even if a part of the gas inside the battery container 101 enters these spaces. Therefore, the pressure of the gas inside the battery container 101 can be measured more accurately.

  The release valve 350 is a valve for opening the gas inside the hollow portion 331 or the like that is in a sealed state at the time of measurement to the outside after the pressure measurement. The release valve 350 is provided with a nail 351 for operating the opening and closing thereof. The open valve 350 is for switching between an open state and a closed state by twisting the nigiri 351. When the release valve 350 is opened, the hollow portion 361 and a hollow portion 371 described later are in communication with each other. That is, the hollow needle 310 and the discharge port 372 are in communication. In a state where the release valve 350 is closed, the hollow portion 361 and the hollow portion 371 are blocked. That is, the hollow needle 310 and the discharge port 372 are not in communication. Thus, the release valve 350 and the nigiri 351 are an opening operation part for releasing the gas inside the hollow part 331 or the like.

  The exhaust part 370 has a hollow part 371 and an exhaust port 372. The hollow part 371 has a hollow inside. The hollow portion 371 communicates with the discharge port 372. The discharge port 372 is connected to a collection container for collecting the exhausted gas. Therefore, the gas whose pressure has been measured is to be recovered in the recovery container. That is, the discharge port 372 is an opening for discharging the air inside the hollow portion 371 to the collection container.

  Here, two states that the gas venting apparatus 300 takes will be described. The two states are an open state of the open valve 350 and a closed sealed state. An open valve 350 is disposed between the hollow portion 361 and the hollow portion 371. For this reason, the hollow portion 361 and the hollow portion 371 are configured to communicate with each other and not communicate with each other.

  That is, when the release valve 350 is open, the hollow portion 361 and the hollow portion 371 are in communication with each other. That is, the hollow portion 312, the hollow portion 331, the hollow portion 361, the hollow portion 371, and the exhaust port 372 are in an open state. Therefore, the gas existing in the space such as the hollow portion can go out from the exhaust port 372. In such an open state, the pressure sensor 340 shows a value of about 1 atmosphere (about 0.1 MPa).

  When the release valve 350 is in a closed state, the hollow portion 361 and the hollow portion 371 are not in communication. On the other hand, the hollow portion 312, the hollow portion 331, and the hollow portion 361 are in communication with each other. Here, if the tip 311 of the hollow needle 310 is in a sealed space, the gas around the pressure sensor 340 is sealed.

  As described above in detail, the degassing apparatus 300 according to the present embodiment includes the pressure sensor 340. Accordingly, the gas inside the degassing object can be extracted from the tip 311 of the hollow needle 310, and the pressure value of the gas inside the degassing object can be measured. Thereby, the degassing apparatus 300 provided with degassing and the pressure measurement of gas is implement | achieved.

4). Battery Manufacturing Method A battery manufacturing method according to the present embodiment will be described. The manufacturing method of the battery 100 according to the present embodiment includes a degassing step of extracting the gas generated inside the battery container 101 after performing initial charge / discharge. In the degassing step, the quality of the battery is also determined by measuring the pressure of the gas discharged from the inside of the battery container 101 using the degassing device 300 described above. Thereby, the manufacturing method of the battery 100 which can perform degassing and the quality determination of a battery is implement | achieved. Therefore, the manufacturing method of the battery 100 of this embodiment will be described focusing on the degassing process.

4-1. Electrode body creation process The manufacturing process of the battery 100 of this embodiment will be described. First, the electrode plate (the positive electrode plate P and the negative electrode plate N) is wound to form the wound electrode body 200. As described above, the order in which the positive electrode plate P, the separator S, the negative electrode plate N, and the separator T to be wound are stacked is as shown in FIG. As shown in FIG. 3, the wound body is wound so that a part of the positive electrode non-coated part P2 protrudes from one end of the wound body and a part of the negative electrode non-coated part N2 protrudes from the other end. It is. Thereby, the wound electrode body 200 is created.

4-2. Next, the wound electrode body 200 to which the positive electrode current collector plate 110 and the negative electrode current collector plate 120 are joined is inserted into the battery container 101. Next, the battery container 101 is covered with a lid 102. Thereafter, an electrolytic solution is injected into the battery container 101. Then, the liquid injection port 105 (see FIG. 6) of the lid 102 is temporarily sealed. Temporary sealing is to temporarily seal the liquid injection port 105 of the lid 102 by the temporary sealing member 103. The temporary sealing member 103 is a seal member. The material is resin. The perforated part 104 is a part that covers the liquid injection port 105 in the temporary sealing member 103. Further, the perforating part 104 is a part where a hole can be perforated in a later degassing step. For this reason, it is preferable that a mark is attached to the perforated portion 104 during the temporary sealing described above. Thereby, the battery 100 is assembled. That is, the electrode body creation process and the electrolyte solution injection process are battery assembly processes for assembling the battery 100.

4-3. Initial charge / discharge process Subsequently, the temporarily sealed battery is charged / discharged. Thereby, an electrode reaction occurs on the surface of the positive electrode mixture layer PA of the positive electrode plate P and the surface of the negative electrode mixture layer NA of the negative electrode plate N. At this time, a gas such as hydrogen gas is generated due to a reduction reaction of water contained in the positive electrode mixture layer PA and the negative electrode mixture layer NA.

4-4. Degassing step 4-4A. State Measurement Step Subsequently, the gas generated inside the battery container 101 is extracted. At that time, the degassing apparatus 300 shown in FIG. 5 is used. FIG. 6 is a diagram illustrating a part of the order of the degassing process for degassing the battery container 101 using the degassing apparatus 300. As shown in the left drawing of FIG. 6, the hollow needle 310 is aligned with the hole portion 104 of the temporary sealing member 103. At this stage, the release valve 350 of the degassing apparatus 300 shown in FIG. 5 is in a closed state.

  As shown in the left diagram of FIG. 6, first, the gas venting device 300 is brought closer to the temporary sealing member 103 of the temporarily sealed battery from above, that is, in the direction of arrow F in FIG. 6. At that time, the distal end portion 311 of the hollow needle 310 is brought close to a position where the liquid injection port 105 inside the lid 102 is provided under the temporary sealing member 103.

  Subsequently, the distal end portion 311 of the hollow needle 310 contacts the perforated portion 104 of the temporary sealing member 103. Next, as shown in the center diagram of FIG. 6, the sealing surface 321 contacts the temporary sealing member 103. At that time, the tip 311 slightly bites into the perforated part 104. This is because the tip 311 slightly protrudes from the sealing surface 321. At this stage, the sealing member 320 is not yet deformed.

  If the degassing device 300 is continuously pushed as it is, the right side in FIG. 6 is obtained. That is, the hollow needle 310 breaks through the hole 104 of the temporary sealing member 103. At that time, the tip 311 of the hollow needle 310 enters the space sealed by the battery container 101 and the lid 102. Thereby, the inside of the battery container 101, the hollow portion 312, the space portion 331 shown in FIG. 5, and the periphery of the pressure sensor 340 communicate with each other. Therefore, the gas inside the battery container 101 enters the hollow needle 310. At this time, the sealing member 320 is deformed by receiving a force at the sealing surface 321.

  When a short time elapses, the pressure inside the battery container 101 and the pressure around the pressure sensor 340 become substantially equal. Note that the pressure inside the battery container 101 hardly changes before and after the insertion of the hollow needle 310. This is because the volume of the hollow portions 312, 331, and 361 communicating with the battery container 101 by inserting the hollow needle 310 is sufficiently small. At this stage, the pressure is measured by the pressure sensor 340.

4-4B. Pass / Fail Judgment Step If the pressure measurement value at this time is equal to or greater than a predetermined threshold, the battery 100 is judged to be “bad”. If the pressure measurement value at this time is smaller than a predetermined threshold value, the battery 100 is determined to be “good”. Then, only what is determined to be “good” at this stage may be sent to the next sealing step. This is because the battery determined to be “bad” can be removed.

Here, an example of the pressure that serves as a threshold value for pass / fail judgment is illustrated. For example, it is assumed that the volume of a space (dead space) that is not occupied by a member such as the wound electrode body 200 or the electrolytic solution within the battery container 101 is 30 cm ³ . In that case, the threshold value is set to 0.15 MPa. This threshold value is a value that needs to be set differently depending on the volume of the dead space and the valve opening pressure of the safety valve provided in the battery 100. For example, the threshold value is set to a smaller value as the dead space is larger. The smaller the dead space, the larger the threshold value is set. This is because, assuming that the same amount of gas is generated in the initial charge / discharge process, the change in the pressure inside the battery container 101 is smaller as the dead space is larger. Moreover, it is preferable to reset another value depending on the type of the positive electrode mixture layer or the negative electrode mixture layer and the specification of the moisture content thereof.

4-4C. Next, the release valve 350 is opened. Thereby, as described above, the hollow portion 361 and the hollow portion 371 communicate with each other. Therefore, the gas inside the battery container 101 is discharged from the exhaust port 372 in the direction of the arrow D. And gas will be collect | recovered in the inside of a collection container. Thereby, the pressure inside the battery container 101 becomes a value substantially equal to 1 atmosphere (about 0.1 MPa). Thereafter, the gas venting device 300 is removed from the battery 100. Note that it is not always necessary to degas the battery 100 that is determined as “defective” by the quality determination.

4-5. Sealing Step Subsequently, the temporary sealing member 103 having a hole is removed from the lid 102 by a degassing step. Then, the hole is covered with a sealing member. Thereafter, the sealing member and the battery container 101 are welded. Thereby, the battery 100 is manufactured.

4-6. High temperature holding treatment process Subsequently, the manufactured battery 100 is placed in a high temperature environment. For example, it is kept at a temperature of 40 ° C. to 65 ° C. for 6 to 24 hours. This stabilizes the output characteristics of the battery 100 (aging effect). Thereafter, various inspection processes may be performed. Further, an inspection process may be interposed between the above processes.

  The manufacturing method of the battery 100 according to the present embodiment is a method having a degassing step of extracting the gas generated by the initial charge / discharge step. In the degassing step, the pressure inside the battery container 101 is measured. Then, the quality of the battery is determined based on the gas pressure. In other words, the inspection process is carried in the manufacturing process. Therefore, defective products (batteries with abnormal internal pressure) can be removed by the method of manufacturing battery 100 according to the present embodiment. Moreover, the battery 100 with a low moisture content of the electrode mixture layer is manufactured.

5. Modification In the present embodiment, a gas venting device 300 including a pressure sensor 340 is provided. However, instead of providing the pressure sensor 340, a flow meter for measuring the amount of gas discharged from the battery 100 may be provided. This is because if the amount of gas generated in the battery container 101 is known, it is possible to determine whether the battery is good or bad. The flow rate of the gas measured here is the amount of gas discharged from the exhaust port 372 from when the tip 311 of the hollow needle 310 is inserted into the holed portion 104 until the gas inside the battery container 101 is exhausted. Cumulative flow rate. That is, the cumulative flow rate of the gas flowing into the degassing device 300 after the hollow needle 310 is inserted into the battery 100 and before the flow into the hollow needle 350 is stopped while the release valve 350 is opened, It is adopted as a state value indicating the quantity.

6). Summary As described above in detail, the method for manufacturing the battery 100 according to the present embodiment is a method including a degassing step of extracting the gas generated by the initial charge / discharge step. In the degassing step, the pressure inside the battery container 101 is measured. Then, the quality of the battery is determined based on the gas pressure. In other words, the inspection process is integrated into the manufacturing process. Therefore, defective products (batteries with abnormal internal pressure) can be removed by the method of manufacturing battery 100 according to the present embodiment. Moreover, the battery 100 with a low moisture content of the electrode mixture layer is manufactured.

  Further, the degassing apparatus 300 according to the present embodiment includes a pressure sensor 340. Accordingly, the gas inside the degassing object can be extracted from the tip 311 of the hollow needle 310, and the pressure value of the gas inside the degassing object can be measured. Thereby, the degassing apparatus 300 that can perform degassing and gas pressure measurement is realized.

  Note that this embodiment is merely an example, and does not limit the present invention. Therefore, the present invention can naturally be improved and modified in various ways without departing from the gist thereof. For example, although the recovery container is connected to the exhaust port 372, it may be opened to the atmosphere without providing the recovery container in some cases. Further, in the present embodiment, the cylindrical wound electrode body 200 is used, but a flat wound electrode body subjected to pressing may be used. Moreover, you may use the electrode body laminated | stacked flatly. That is, it does not depend on the shape of an electrode body. Although the resin sealing member is used as the temporary sealing member, a rubber plug may be used instead.

(Second Embodiment)
Next, a second embodiment will be described. In the present embodiment, the battery 100 is manufactured using the gas venting device 300 as in the first embodiment. Therefore, there is no change in performing degassing and gas pressure measurement. The difference between the manufacturing method of the battery 100 of this embodiment and the manufacturing method of the battery 100 of the first embodiment is a threshold setting method used for pass / fail determination. Therefore, this difference will be mainly described.

  In the present embodiment, the pressure threshold used for the quality determination of the battery 100 is changed according to various external parameters.

  FIG. 7 is a graph showing values obtained by measuring the internal pressure of a battery prepared under various environments. The horizontal axis in FIG. 7 represents the battery sample creation number. Samples with different creation numbers are batteries created under different conditions. The vertical axis represents the internal pressure of the sample. The experiment in FIG. 7 is not intended to search for a battery having an abnormal internal pressure, but whether the internal pressure value of the battery changes in a direction of increasing or decreasing depending on various external parameters. This was done to investigate the trend. Therefore, the pressure value of each lot shown in the graph of FIG. 7 is smaller than 0.15 MPa adopted as the pass / fail judgment threshold in the first embodiment.

  Of course, the pressure inside the battery container changes due to dead space or the like as described above. Therefore, these tests are common except for the changed external parameters.

  The data existing in the region indicated by G in FIG. 7 is a long time from the end time of the electrolyte injection process to the start time of temporary sealing. The data existing in the region represented by H in FIG. 7 is a short time from the end time of the electrolyte injection process to the start time of temporary sealing.

  In FIG. 7, the pressure value of the data existing in the area represented by G tends to be larger than the pressure value of the data existing in the area represented by H. That is, the shorter the time from the end time of the electrolyte injection process to the start time of temporary sealing, the smaller the pressure inside the battery container 101 tends to be. The longer the time from the end time of the electrolyte injection process to the start time of temporary sealing, the greater the pressure inside the battery container 101.

  Therefore, in this embodiment, the shorter the time from the end time of the electrolytic solution injection process to the start time of temporary sealing, the smaller the threshold value is set, and from the end time of the electrolytic solution injection process to the start time of temporary sealing. The longer the time is, the larger the threshold is set.

  The data existing in the region represented by I in FIG. 7 is a long time from the end time of the initial charge / discharge process to the start time of the high temperature holding treatment process. The data existing in the region represented by J in FIG. 7 is a short time from the end time of the initial charge / discharge process to the start time of the high temperature holding treatment process.

  In FIG. 7, the pressure value of the data existing in the area represented by I tends to be smaller than the pressure value of the data existing in the area represented by J. That is, as the time from the end time of the initial charge / discharge process to the start time of the high temperature holding process is shorter, the internal pressure of the battery container 101 tends to increase. The longer the time from the end time of the initial charge / discharge process to the start time of the high temperature holding process, the smaller the pressure inside the battery container 101 tends to be.

  Therefore, in this embodiment, the shorter the time from the end time of the initial charge / discharge process to the start time of the high temperature holding process, the larger the threshold value is set, and the start of the high temperature holding process starts from the end time of the initial charge / discharge process. The longer the time until the time is, the smaller the threshold value is set.

  The data existing in the region represented by K in FIG. 7 uses an electrode plate having a lower moisture content than the data present in the region represented by L in FIG.

  As described above in detail, the method for manufacturing the battery 100 according to the present embodiment is a method including a degassing process for extracting gas generated by the initial charge / discharge process. In the degassing step, the pressure inside the battery container 101 is measured. Then, the quality of the battery is determined based on the gas pressure. In other words, the inspection process is integrated into the manufacturing process. Therefore, defective products (batteries with abnormal internal pressure) can be removed by the method of manufacturing battery 100 according to the present embodiment. Moreover, the battery 100 with a low moisture content of the electrode mixture layer is manufactured.

  Further, the degassing apparatus 300 according to the present embodiment includes a pressure sensor 340. Accordingly, the gas inside the degassing object can be extracted from the tip 311 of the hollow needle 310, and the pressure value of the gas inside the degassing object can be measured. Thereby, the degassing apparatus 300 that can perform degassing and gas pressure measurement is realized.

  Note that this embodiment is merely an example, and does not limit the present invention. Therefore, the present invention can naturally be improved and modified in various ways without departing from the gist thereof. For example, although the recovery container is connected to the exhaust port 372, it may be opened to the atmosphere without providing the recovery container in some cases. Further, in the present embodiment, the cylindrical wound electrode body 200 is used, but a flat wound electrode body subjected to pressing may be used. Moreover, you may use the electrode body laminated | stacked flatly. That is, it does not depend on the shape of an electrode body. Although the resin sealing member is used as the temporary sealing member, a rubber plug may be used instead.

DESCRIPTION OF SYMBOLS 100 ... Battery 101 ... Battery container 102 ... Cover 103 ... Temporary sealing member 104 ... Hole opening part 105 ... Injection hole 200 ... Winding electrode body 300 ... Degassing device 310 ... Hollow needle 311 ... Tip part 312,331,361 , 371 ... Hollow part 320 ... Sealing member 321 ... Sealing surface 330, 360 ... Connection part 340 ... Pressure sensor 350 ... Opening valve 372 ... Exhaust port P ... Positive electrode plate PA ... Positive electrode mixture layer PB ... Positive electrode core material P1 ... Positive electrode coating part P2 ... Positive electrode non-coating part N ... Negative electrode plate NA ... Negative electrode composite layer NB ... Negative electrode core material N1 ... Negative electrode coating part N2 ... Negative electrode non-coating part S, T ... Separator

Claims (10)

A battery assembly process for inserting an electrode body in which positive and negative electrode plates and separators for insulating them are stacked into a battery case and injecting an electrolyte into the battery case;
An initial charge / discharge step in which the battery case is once sealed and charged / discharged after the battery assembly step;
A degassing step of removing the gas inside the battery case from the battery case after the initial charge and discharge step;
In the secondary battery manufacturing method having a sealing step of sealing the battery case after the degassing step,
The degassing process includes:
A state measurement step of measuring a state value indicating the amount of gas generated inside the battery case in the initial charge / discharge step;
When the state value measured in the state measurement step is larger than a predetermined threshold value,
The secondary battery is determined to be defective,
When the state value measured in the state measurement step is a value equal to or less than a predetermined threshold value,
A pass / fail judgment step for judging that the secondary battery is non-defective,
A method for producing a secondary battery, comprising: a gas exhausting process for exhausting a gas inside the battery case in a secondary battery determined to be a non-defective product in the pass / fail determination process to the outside of the battery case. In the manufacturing method of the secondary battery according to claim 1,
In the degassing process,
A method of manufacturing a secondary battery, wherein the state value is a pressure inside the battery case. In the manufacturing method of the secondary battery according to claim 1,
In the degassing process,
As the state value, a cumulative flow rate of gas flowing out from the inside of the battery case in the gas discharging step is used. In the manufacturing method of the secondary battery in any one of Claim 1 to Claim 3,
A time from the end time of the battery assembly process to the start time of the sealing process is set in advance as a set time,
A method of manufacturing a secondary battery, wherein the threshold value is corrected according to the set time. In the manufacturing method of the secondary battery according to claim 4,
Using at least a first set time and a first threshold corresponding thereto, a second set time longer than the first set time and a second threshold corresponding thereto,
The method for manufacturing a secondary battery, wherein the first threshold value is smaller than the second threshold value. In the manufacturing method of the secondary battery in any one of Claim 1 to Claim 3,
Having a high temperature holding treatment step of holding at a temperature of 40 ° C. to 65 ° C. for at least 6 hours after the sealing step;
The time from the end time of the initial charge / discharge process to the start time of the high temperature holding process is set in advance as a process setting time,
A method of manufacturing a secondary battery, wherein the threshold value is corrected according to the processing setting time. In the manufacturing method of the secondary battery according to claim 6,
Using at least a first process setting time and a first threshold corresponding thereto, a second process setting time longer than the first process setting time and a second threshold corresponding thereto,
The method for manufacturing a secondary battery, wherein the first threshold value is larger than the second threshold value. A hollow needle having an open tip inserted into an object containing gas and having a hollow inside;
A communicating portion communicating with the hollow needle;
An exhaust port for communicating with the communication portion and exhausting gas from the communication portion;
In the degassing device having an open / close valve for switching presence / absence of communication between the hollow needle and the exhaust port,
A degassing apparatus comprising a state measuring unit that measures a state value indicating an amount of gas incorporated in the object. The degassing device according to claim 8,
The state value is
The degassing device, wherein the degassing device is a pressure value of gas flowing from the object into the communication portion via the hollow needle. The degassing device according to claim 8,
The state value is
The flow rate of the gas flowing into the degassing device after the hollow needle is inserted into the object and before the flow into the hollow needle is stopped with the open / close valve opened. Degassing device.

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