Manufacturing method of electric storage device

Abstract

To provide a manufacturing method of an electric storage device, capable of correcting an accuracy necessary surface of a sealing body within a reference value by changing a correction deformation magnitude in accordance with a wrapping displacement magnitude of the sealing body.SOLUTION: The present invention provides a manufacturing method of an electric storage device 10 having a correction step S4 of correcting a sealing body 12. The manufacturing method contains: a data base formation step S1 of having an accuracy necessary surface 12S in the sealing body, and accumulating correlation graph data SKD of a wrapping displacement magnitude Q of a front and back direction (a z-direction) of an accuracy necessary surface against a support point 12K of the sealing body and a correction deformation magnitude P in which the accuracy necessary surface is corrected and deformed to front and back opposite directions to a position where an accuracy requirement surface can be recovered to a normal position SK by own elastic force; a surface modulation measurement step S2 of measuring the wrapping displacement magnitude; and a displacement magnitude determination step S3 of determining whether the wrapping displacement magnitude satisfies a reference value KJ. In the correction step, a load is applied until the correction deformation magnitude occurs when the wrapping displacement magnitude to be measured in the surface modulation measurement step to the accuracy necessary surface in a determination rejection is matched to the wrapping displacement magnitude in the correlation graph data to be released.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The disclosed technology relates to a method for manufacturing a power storage device.

Background Art

[0002] Conventionally, in a power storage device having an electrode body in a case, when joining the end portion of the electrode body (non-coated portion of the active material) and the current collector terminal, etc., an external force is applied to the current collector terminal, and a phenomenon occurs in which the current collector terminal is deformed. Then, due to the deformation of the current collector terminal, etc., the sealing body of the case in which the positive and negative current collector terminals are coupled to both end portions in the longitudinal direction may be warped and displaced in the front-back direction asymmetrically left and right.

[0003] In this regard, for example, Patent Document 1 and Patent Document 2 disclose technologies for reducing the deformation of the current collector terminal with respect to an external force by increasing the rigidity of the current collector terminal.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, even if the rigidity of the current collector terminal is increased, the rigidity of the sealing body is generally lower than that of the current collector terminal. Therefore, there is a problem that the external force acting on the current collector terminal is transmitted almost as it is to the sealing body to which the current collector terminal is coupled, and the warping of the sealing body cannot be sufficiently suppressed. In addition, there is a problem that the amount of warping displacement of the sealing body varies in size for each power storage device to be manufactured. And usually, on the surface of the sealing body, there is a surface that requires accuracy, such as a sensor contact surface formed so as to be in contact with, for example, a temperature sensor for monitoring the temperature of the power storage device, and it is necessary to ensure better surface position accuracy than other parts. It was necessary to guarantee that the surface position accuracy of the surface requiring accuracy was within the required reference value.

[0006] The present disclosure technology has been made in view of such problems. Even when the amount of warping displacement of the sealing body varies for each power storage device to be manufactured and the amount of warping displacement is asymmetric left and right, the amount of corrective deformation is changed according to the amount of warping displacement. An object of the present invention is to provide a method for manufacturing a highly reliable power storage device that can correct a surface that requires accuracy of a sealing body within a reference value.

Means for Solving the Problems

[0007] (1) One aspect of the disclosed technology for solving the above problems is a method for manufacturing a power storage device including a correction step of correcting a sealing body that seals an opening of a case housing an electrode body, before a sealing body welding step of welding the sealing body to the opening. The surface of the sealing body has a precision-required surface that requires a required surface position accuracy. The amount of warpage displacement in the front-back direction of the precision-required surface with respect to the support point of the sealing body inserted into the opening, and the precision-required surface displaced by the amount of warpage displacement is restored to a normal position where the warpage displacement Q becomes zero by its own elastic force up to a position where it is corrected and deformed in a direction opposite to the displacement direction with respect to the support point 12K of the precision-required surface 12S. A database formation step of accumulating in advance the correlation graph data between the amount of warpage displacement and the amount of correction deformation; a surface displacement measurement step of measuring the amount of warpage displacement of the precision-required surface after inserting the sealing body into the opening; and a displacement amount determination step of determining whether or not the amount of warpage displacement of the precision-required surface measured in the surface displacement measurement step satisfies a required reference value. In the correction step, when it is determined in the displacement amount determination step that the amount of warpage displacement does not satisfy the required reference value, a load is applied to the precision-required surface up to a position where the amount of correction deformation occurs when the amount of warpage displacement measured in the surface displacement measurement step coincides with the amount of warpage displacement in the correlation graph data, and then the load is released. This is a method for manufacturing a power storage device.

[0008] (2) In the method for manufacturing a power storage device according to claim 1, it is preferable that the precision-required surface 12S is a sensor contact surface formed so as to be in contact with a temperature sensor that monitors the temperature of the power storage device.

[0009] (3) In the method for manufacturing an electricity storage device according to claim 1 or claim 2, the surface of the sealing body has a plurality of surfaces that require precision, and in the surface displacement measurement step, the warp displacement amount of each of the surfaces that require precision is measured. In the correction step, when it is determined in the displacement amount determination step that at least one of the warp displacement amounts does not satisfy a required reference value, for each of the surfaces that require precision, a load is applied until the average value of the correction deformation amounts when the warp displacement amounts measured in the surface displacement measurement step match the warp displacement amounts in the correlation graph data, and then the load is released.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Embodiments for Carrying Out the Invention

[0011] <Overall Description of This Power Storage Device> Next, the overall configuration of a power storage device manufactured by a method for manufacturing a power storage device according to an aspect of the above-disclosed technology will be described in detail with reference to the drawings. FIG. 1 shows a schematic plan view of a power storage device manufactured by a method for manufacturing a power storage device according to an aspect of the present embodiment. FIG. 2 shows a schematic cross-sectional view of the A-A cross-section shown in FIG. 1, in a state where a temperature sensor is in contact with the sensor contact surface of the sealing body. FIG. 3 shows a schematic perspective view showing a state where a part of the electrode body shown in FIG. 2 is unwound. FIG. 4 shows the B-B cross-section shown in FIG. 2. Note that in each figure, the X direction indicates the longitudinal direction of the sealing body, the Y direction indicates the short-side direction of the sealing body, and the Z direction indicates the front-back direction of the sealing body.

[0012] As shown in FIGS. 1 to 4, the power storage device 10 manufactured by the method for manufacturing this power storage device includes a case 1, an electrode body 2, and a current collecting terminal 4. Here, as shown in FIGS. 1 and 2, the case 1 includes a bottomed rectangular tube-shaped case body 11 having a rectangular opening 111, and a long and flat sealing body 12 that seals the opening 111. The sealing body 12 is provided with an injection port 123 for injecting the electrolytic solution 8 into the case 1, a plug body 122 for sealing the injection port 123, and a safety valve 124 that cracks when the pressure in the case 1 rises above a predetermined value. Both the case body 11 and the sealing body 12 are made of aluminum, but for the necessity of improving the valve-opening performance of the safety valve 124, a material that is softer and more easily deformable than the current collecting terminal 4 is used for the sealing body 12.

[0013] Further, in the opening 111 of the case body 11, the thin portion 111T is formed only on the inner walls of the short side surfaces 11C and 11D. Therefore, both end portions 12R in the longitudinal direction (X direction) of the sealing body 12 inserted into the opening 111 are supported by the step portion 111S formed at the lower end of the thin portion 111T, corresponding to the support points 12K of the sealing body 12. Note that in the opening 111 of the case body 11, there is no thin portion on the inner walls of the long side surfaces 11A and 11B, and the structure makes it difficult to prevent the central portion of the sealing body 12 from being displaced (warped) in the front-rear direction (Z direction).

[0014] Further, as shown in FIGS. 2 to 4, the electrode body 2 has a positive electrode body 21 and a negative electrode body 22 laminated with a separator 23 interposed therebetween, wound in a flat shape, and housed in the case body 11. The positive electrode body 21 and the negative electrode body 22 each have an active material non-coated portion 211, 221 where the active materials KT1, KT2 are not coated on one end portions 21K1, 22K1 of the metal foils 21K, 22K, and an active material coated portion 212, 222 where the active materials KT1, KT2 are coated on the metal foils 21K, 22K. The active material non-coated portion 211 of the positive electrode body 21 and the active material non-coated portion 221 of the negative electrode body 22 are arranged to face each other in the longitudinal direction (X direction) of the sealing body 12. Further, the active material coated portions 212, 222 are formed at the other end portions 21K2, 22K2 and the intermediate portions 21K3, 22K3 of the metal foils 21K, 22K.

[0015] The power storage device 10 means all power storage devices capable of extracting electrical energy, and includes, for example, primary batteries, secondary batteries, electric double layer capacitors, etc. For example, in a lithium ion secondary battery, the metal foil 21K of the positive electrode body 21 uses, for example, an aluminum foil, and the active material KT1 coated thereon is, for example, a lithium transition metal oxide (LiNi 1 / 3 Co 1 / 3 Mn 1 / 3It is possible to use, for example, O2, LiNiO2, etc. Also, for the metal foil 22K of the negative electrode body 22, for example, a copper foil can be used, and as the active material KT2 coated thereon, for example, graphite, hard carbon, soft carbon, etc. can be used. Further, for the separator 23, for example, a porous sheet such as polypropylene or polyethylene can be used. Note that as the electrolytic solution 8, a known non-aqueous electrolytic solution can be used.

[0016] Also, the current collector terminal 4 includes a positive current collector terminal 4A and a negative current collector terminal 4B. The positive current collector terminal 4A is made of, for example, aluminum, and the negative current collector terminal 4B is made of, for example, copper. Usually, the tensile strength of the aluminum positive current collector terminal 4A is smaller than that of the copper negative current collector terminal 4B, and the conductivity of the positive current collector terminal 4A is smaller than that of the negative current collector terminal 4B. Therefore, in order to equalize the strength and allowable current of the positive current collector terminal 4A and the negative current collector terminal 4B, the plate thickness of the positive current collector terminal 4A is made larger than that of the negative current collector terminal 4B. The positive and negative current collector terminals 4 each have a base portion 41, a base adjacent portion 42, and a lead portion 43 that are integrally formed.

[0017] The base portion 41 is coupled, for example, by caulking pins 46 or the like to an external connection portion 45 (45A, 45B) located on the surface side of the sealing body 12. Due to the external force when coupling the base portion 41, the external connection portion 45, and the sealing body 12 by the caulking pins 46 or the like, the central portion of the sealing body 12 may be displaced in the front-back direction (Z direction). Note that an insulating member 3 that also serves as a sealing material is interposed between the caulking pins 46, the external connection portion 45, and the sealing body 12. As the insulating member 3, for example, a polyphenylene sulfide (PPS) resin can be used. When a plurality of the power storage devices 10 are connected to the external connection portion 45 (45A, 45B), a connection bus bar (not shown) is connected thereto.

[0018] Further, the base portion 41 is coupled to the back surface sides of both end portions 12R in the longitudinal direction (X direction) of the sealing body 12 with the insulating member 3 interposed therebetween. Further, the base adjacent portion 42 is adjacent to the base portion 41 and is in contact with the insulating member 3. The upper end portion 43a of the lead portion 43 is bent from the base adjacent portion 42 in the case inward direction (Z direction), and the metal foils 21K and 22K of the non-active material coated portions 211 and 221 of the electrode body 2 are in a state of being collected into a foil and are welded and joined to the lower end portion 43b of the lead. When welding the electrode body 2 and the lower end portion 43b of the lead, an external force that causes the lower end portion 43b of the lead to slide or the like with respect to the metal foils 21K and 22K during the collection of the foil is likely to occur, and this external force is transmitted to the sealing body 12, and the central portion of the sealing body 12 may be displaced in the front-back direction (Z direction).

[0019] Further, the surface 121 of the sealing body 12 has two precision-required surfaces 12S (12S1, 12S2) that require a required surface position accuracy. Here, the precision-required surfaces 12S (12S1, 12S2) are sensor contact surfaces 5S formed to be in contact with the temperature sensor 5 that monitors the temperature of the power storage device 10, but it is not necessarily limited to the sensor contact surfaces 5S. The temperature sensor 5 can use, for example, a thermistor or a thermocouple. The temperature sensor 5 is held in a holding case 51 fixed to the mounting bracket 53 and is biased against the sensor contact surface 5S by a spring member 52 or the like. In consideration of various manufacturing errors, in order to guarantee the measurement accuracy of the temperature sensor 5, it is required that the surface position accuracy of the sensor contact surface 5S satisfies a required reference value KJ.

[0020] When a plurality of the main power storage devices 10 are connected in series to form a battery pack, usually, the long side surfaces 11A and 11B of the case main body 11 are arranged close to each other, so that the external connection portions 45A of the positive electrodes and the external connection portions 45B of the negative electrodes are alternately arranged in the same direction. Therefore, the sensor contact surface 5S may be formed on the surface 12S (12S1) that requires accuracy near the external connection portion 45A of the positive electrode (the case shown in FIG. 2), or may be formed on the surface 12S (12S2) that requires accuracy near the external connection portion 45B of the negative electrode. It is required that the surface position accuracy of both surfaces 12S (12S1, 12S2) that require accuracy satisfies the required reference value KJ.

[0021] <Manufacturing method of the main power storage device> Next, the manufacturing method of the power storage device according to the present embodiment will be described in detail with reference to the drawings. FIG. 5 shows a flowchart representing the manufacturing method of the power storage device shown in FIG. 1. FIG. 6 shows an example of correlation graph data accumulated in the database formation step of the flowchart shown in FIG. 5. FIG. 7 shows a schematic cross-sectional view representing a measurement method for measuring the warpage displacement amount of the surface that requires accuracy in the database formation step and the surface displacement measurement step of the flowchart shown in FIG. 5. FIG. 8 shows a schematic cross-sectional view of a correction device for correcting the warpage displacement amount of the surface that requires accuracy in the correction step of the flowchart shown in FIG. 5. FIG. 9 shows a schematic cross-sectional view when a load is applied to the surface that requires accuracy so that a correction deformation amount occurs in the correction device shown in FIG. 8. FIG. 10 shows a schematic cross-sectional view when the load applied to the surface that requires accuracy so that a correction deformation amount occurs in the correction device shown in FIG. 8 is released.

[0022] As shown in FIGS. 1 to 10, the method for manufacturing the power storage device includes a correction step S4 of correcting a sealing body 12 that seals an opening 111 of a case 1 housing an electrode body 2, before a sealing body welding step S5 of welding the sealing body 12 to the opening 111. The method for manufacturing the power storage device 10 has a required surface position accuracy surface 12S on the surface 121 of the sealing body 12. The method for manufacturing the power storage device includes a database formation step S1, a surface displacement measurement step S2, a displacement amount determination step S3, a correction step S4, and a sealing body welding step S5. The sealing body welding step S5 is a step of welding the outer periphery of the sealing body 12 determined in the displacement amount determination step S3 to satisfy the warp displacement amount Q of the accuracy required surface 12S with the reference value KJ, or the outer periphery of the sealing body 12 corrected within the reference value KJ of the warp displacement amount Q of the accuracy required surface 12S in the correction step S4 to the opening 111 by laser welding or the like. In FIGS. 7 to 10, the electrode body 2 is omitted, but as shown in FIG. 2, the electrode body 2 is coupled to the sealing body 12 via a current collecting terminal 4.

[0023] Here, the accuracy required surface 12S will be described by taking an example of a sensor contact surface 5S formed so as to be in contact with a temperature sensor 5 that monitors the temperature of the power storage device 10 as described above. As shown in FIGS. 1, 2, 6, and 7, the sensor contact surface 5S is a flat rectangular surface, and is formed on the accuracy required surface 12S (12S1) near the external connection portion 45A of the positive electrode and the accuracy required surface 12S (12S2) near the external connection portion 45B of the negative electrode. The surface position accuracy of both accuracy required surfaces 12S (12S1, 12S2) is required to satisfy a required reference value KJ.

[0024] Note that the reference value KJ means the allowable value of the warpage displacement amount Q in which the surface positions of the precision-required surfaces 12S (12S1, 12S2) are displaced in the front-back direction (Z direction) of the sealing body 12 with respect to the support points 12K of the sealing body 12. The reference value KJ is, for example, about ±0.2 to 0.3 mm. The displacement in the front surface direction (Z direction) of the sealing body 12 is represented by +, and the displacement in the back surface direction (Z direction) of the sealing body 12 is represented by -. The correlation graph data SKD shown in FIG. 6 is an example when the surface positions of the precision-required surfaces 12S (12S1, 12S2) are displaced in the front surface direction (Z direction) of the sealing body 12. Since the precision-required surface 12S is the sensor contact surface 5S formed to be in contact with the temperature sensor 5 that monitors the temperature of the power storage device 10, the measurement accuracy of the temperature sensor 5 can be improved, and an excessive temperature rise of the power storage device 10 can be avoided. Therefore, the safety and reliability of the power storage device 10 can be further enhanced.

[0025] Further, the database formation step S1 is a step of pre-accumulating the correlation graph data SKD of the warpage displacement amount Q in the front-back direction (Z direction) of the precision-required surfaces 12S (12S1, 12S2) and the correction deformation amount P for correcting and deforming the precision-required surfaces 12S (12S1, 12S2) displaced by the warpage displacement amount Q to a position where the warpage displacement amount Q becomes zero at the normal position SK that can be restored by its own elastic force in the direction opposite to the displacement direction with respect to the support points 12K (12K1, 12K2) of the precision-required surfaces 12S.

[0026] The correlation graph data SKD is produced, for example, by the following procedure. First, a sealed body 12 in which the electrode body 2 is coupled via the current collector terminal 4 is inserted into the opening 111 of the case body 11. Next, as shown in FIG. 7, the surface positions of the accuracy-required surfaces 12S (12S1, 12S2) of the sealed body 12 in the front-back direction (Z direction) of the sealed body 12 are measured. The surface position measuring device is preferably a non-contact measuring device 6 having, for example, laser distance meters 61 and 62. Here, the surface positions are measured by irradiating the central portions of the accuracy-required surfaces 12S (12S1, 12S2) with the laser light of the laser distance meters 61 and 62. The measuring device 6 calculates the warp displacement amount Q in the front-back direction (Z direction) as the difference between the surface positions of the respective accuracy-required surfaces 12S (12S1, 12S2) measured by the laser distance meters 61 and 62 and the surface position of the reference support point 12K. Then, the surface positions of the accuracy-required surfaces 12S (12S1, 12S2) of the sealed bodies 12 with different warp displacement amounts Q are measured, and the various warp displacement amounts Q are transferred to the database of the correction device 7 shown in FIG. 8.

[0027] Next, as shown in FIG. 9, the operating parts 71 and 72 of the correction device 7 operate, and the accuracy-required surfaces 12S (12S1, 12S2) displaced by the respective warp displacement amounts Q are corrected and deformed by applying a load F in the direction opposite to the displacement direction with respect to the support points 12K (12K1, 12K2) of the accuracy-required surfaces 12S in the front-back opposite direction (Z direction) until they are restored to a normal position SK where the warp displacement amount Q becomes zero by their own elastic force. Then, as shown in FIG. 10, the operating parts 71 and 72 are returned to their original positions, and the load F is released. The operating parts 71 and 72 of the correction device 7 are preferably driven by a servo motor with an encoder or the like and have a structure capable of accurately controlling the amount of movement. Note that the operating parts 71 and 72 of the correction device 7 may repeat the correction deformation and release in multiple steps and gradually increase the amount of deformation until a predetermined correction deformation amount P is reached.

[0028] Then, the correction device 7 creates correlation graph data SKD (SKD1, SKD2) of the warpage displacement amount Q transferred from the measurement device 6 and the correction deformation amount P when the correction deformation is performed by applying this load F, as shown in FIG. 6, and stores it in the database. Note that the operating units 71 and 72 of the correction device 7 can be switched to a structure (for example, a suction structure or a hooking structure, etc.) that can apply the load F in the direction opposite to the displacement direction of the accuracy required surface 12S (Z direction), even when the accuracy required surface 12S (12S1, 12S2) is displaced to the back side of the sealing body 12.

[0029] Here, the correlation graph data SKD1 is a correlation curve representing the correlation between the warpage displacement amount Q and the correction deformation amount P of the accuracy required surface 12S (12S1) near the external connection portion 45A of the positive electrode. Further, the correlation graph data SKD2 is a correlation curve representing the correlation between the warpage displacement amount Q and the correction deformation amount P of the accuracy required surface 12S (12S2) near the external connection portion 45B of the negative electrode. The correlation graph data SKD1 and SKD2 shown in FIG. 6 are displayed as a line graph, but they may be displayed as a curve graph by increasing the measurement data.

[0030] As shown in FIG. 6, in the region where the warp displacement amount Q is within the reference value KJ, the difference in the respective warp displacement amounts Q for the same correction deformation amount P between the correlation graph data SKD1 and the correlation graph data SKD2 is small. However, in the region where the warp displacement amount Q exceeds the reference value KJ, it can be seen that the difference in the respective warp displacement amounts Q for the same correction deformation amount P increases. This is presumably because the injection port 123 and the safety valve 124, which are factors causing a decrease in the strength of the sealing body 12, are present on the side of the accuracy-required surface 12S (12S1) closer to the external connection portion 45A of the positive electrode. However, in the power storage device 10 to be manufactured, even when the warp displacement amount Q of the sealing body 12 varies from one power storage device 10 to be manufactured and is different between the positive electrode side and the negative electrode side, based on the correlation graph data SKD (SKD1, SKD2) accumulated in the database formation step S1, the correction deformation amount P for correcting the warp displacement amount Q can be easily and accurately obtained. Note that the correlation graph data SKD (SKD1, SKD2) accumulated in the database formation step S1 differs depending on the size, type, etc. of the power storage device 10. Therefore, it is advisable to prepare the correlation graph data SKD (SKD1, SKD2) in advance for each power storage device 10 and accumulate it in the database.

[0031] Also, as shown in FIG. 5, after inserting the sealing body 12 into the opening 111 in the surface displacement measurement step S2, the warp displacement amounts Q (Q1, Q2) of the accuracy-required surfaces 12S (12S1, 12S2) are measured. In the displacement amount determination step S3, it is determined whether or not the warp displacement amounts Q (Q1, Q2) of the accuracy-required surfaces 12S (12S1, 12S2) measured in the surface displacement measurement step S2 satisfy the required reference value KJ. As described above, the method of measuring the warp displacement amounts Q (Q1, Q2) of the accuracy-required surface 12S in the surface displacement measurement step S2 is performed by the measuring device 6 shown in FIG. 7.

[0032] Therefore, before welding the sealing body 12 to the opening 111, the surface positions of the precision-required surfaces 12S (12S1, 12S2) can be measured, and their quality can be determined. As a result, it is not necessary to consider various causes that cause warping of the sealing body 12. Also, it is not necessary to measure the surface positions other than the precision-required surfaces 12S and determine their quality. Therefore, the surface displacement measurement step S2 and the displacement amount determination step S3 can be simplified, contributing to an improvement in productivity.

[0033] Also, as shown in FIGS. 6, 9, and 10, in the correction step S4, when it is determined in the displacement amount determination step S3 that the warpage displacement amounts Q (Q1, Q2) do not satisfy the required reference value KJ, a load F (F1, F2) is applied to the precision-required surfaces 12S (12S1, 12S2) until the correction deformation amounts P (P1, P2) occur at positions where the warpage displacement amounts Q (Q1, Q2) measured in the surface displacement measurement step S2 coincide with the warpage displacement amounts Q (Q1, Q2) in the correlation graph data SKD (SKD1, SKD2), and then the load F (F1, F2) is released.

[0034] Thereby, the warpage displacement amounts Q (Q1, Q2) can be corrected, focusing on the precision-required surfaces 12S (12S1, 12S2) for which the warpage displacement amounts Q (Q1, Q2) do not satisfy the required reference value KJ. Note that the correction deformation amounts P (P1, P2) are deformation amounts that can restore the precision-required surfaces 12S (12S1, 12S2) that have been displaced by only the warpage displacement amounts Q (Q1, Q2) to the normal position SK where the warpage displacement amount Q becomes zero by their own elastic force. Therefore, the difference obtained by subtracting the elastic deformation amounts DH (DH1, DH2) from the correction deformation amounts P (P1, P2) becomes the plastic deformation amounts SH (SH1, SH2) after correction, which coincide with the warpage displacement amounts Q (Q1, Q2) before correction.

[0035] As described in detail above, the method for manufacturing a power storage device according to the present embodiment is a method for manufacturing a power storage device 10 including a correction step S4 of correcting a sealing body 12 that seals an opening 111 of a case 1 housing an electrode body 2, before a sealing body welding step S5 of welding the sealing body 12 to the opening 111. On the surface 121 of the sealing body 12, there is a precision-required surface 12S that requires a required surface position accuracy. The warp displacement amount Q in the front-back direction (Z direction) of the precision-required surface 12S with respect to the support points 12K (12K1, 12K2) of the sealing body 12 inserted into the opening 111, and the precision-required surface 12S displaced by the warp displacement amount Q is restored to a normal position SK where the warp displacement amount Q becomes zero by its own elastic force. A database formation step S1 of accumulating in advance the correlation graph data SKD of the correction deformation amount P corrected in the displacement direction opposite to the front-back direction (Z direction) with respect to the support points 12K of the precision-required surface 12S to a position where it can be restored; a surface displacement measurement step S2 of measuring the warp displacement amount Q of the precision-required surface 12S after inserting the sealing body 12 into the opening 111; and a displacement amount determination step S3 of determining whether or not the warp displacement amount Q of the precision-required surface 12S measured in the surface displacement measurement step S2 satisfies a required reference value KJ. In the correction step S4, when it is determined in the displacement amount determination step S3 that the warp displacement amount Q does not satisfy the required reference value KJ, a load F is applied to the precision-required surface 12S until the position where the correction deformation amount P occurs when the warp displacement amount Q measured in the surface displacement measurement step S2 coincides with the warp displacement amount Q in the correlation graph data SKD, and then the load F is released. This is a method for manufacturing a power storage device.

[0036] Therefore, according to the method for manufacturing the present power storage device 10, the warp displacement amount Q of the sealing body 12 is different for each power storage device 10 to be manufactured. Even when the warp displacement amount Q is left-right asymmetric, the correction deformation amount P can be changed according to the warp displacement amount Q, and the precision-required surface 12S of the sealing body 12 can be corrected within the reference value KJ, thereby providing a method for manufacturing a highly reliable power storage device.

[0037] Also, in the manufacturing method of this power storage device, the surface 121 of the sealing body 12 has a plurality of surfaces requiring precision (12S1, 12S2). In the surface displacement measurement step S2, the warp displacement amounts Q (Q1B, Q2) of the respective surfaces requiring precision 12S (12S1, 12S2) are measured. In the correction step S4, when it is determined in the displacement amount determination step S3 that at least one warp displacement amount Q (Q2) does not satisfy the required reference value KJ, for each surface requiring precision 12S (12S1, 12S2), the respective warp displacement amounts Q (Q1B, Q2) measured in the surface displacement measurement step S2 are such that when they match the warp displacement amounts Q (Q1B, Q2) in the correlation graph data SKD (SKD1, SKD2) shown in FIG. 6, a load F (F1, F2) is applied until the average value (P1B + P2) × 1 / 2 of the correction deformation amounts P (P1B, P2) occurs, and then the load F (F1, F2) is preferably released.

[0038] In this case, even if there are a plurality of surfaces requiring precision 12S (12S1, 12S2), after applying a load F (F1, F2) until the average value (P1B + P2) × 1 / 2 of the correction deformation amounts P (P1B, P2) occurs when the respective warp displacement amounts Q (Q1B, Q2) measured in the surface displacement measurement step S2 match the warp displacement amounts Q (Q1B, Q2) in the correlation graph data SKD (SKD1, SKD2), and then releasing the load F (F1, F2), it is not necessary to generate individual correction deformation amounts P (P1B, P2) for the plurality of surfaces requiring precision 12S (12S1, 12S2), and the correction device 7 for applying the load F (F1, F2) to the surfaces requiring precision 12S (12S1, 12S2) can be simplified. Therefore, the surfaces requiring precision 12S of the sealing body 12 can be corrected within the reference value KJ at a lower cost and in a shorter time.

[0039] <Modification Example> As described in detail above, the present embodiment is merely an example and does not limit the disclosed technology in any way. Therefore, the disclosed technology can be variously improved and modified without departing from its gist.

Description of Reference Numerals

[0040] 1 Case 2 Electrode body 5 Temperature sensor 5S Sensor contact surface 10 Energy storage device 12 Sealing body 12K, 12K1, 12K2 Support points 12S, 12S1, 12S2 Surfaces requiring precision 111 Opening 121 Surface F, F1, F2 Load KJ Reference value P, P1, P1B, P2 Correction deformation amount Q, Q1, Q1B, Q2 Warping displacement amount S1 Database formation process S2 Surface displacement measurement process S3 Displacement amount determination process S4 Correction process S5 Sealing body welding process SK Normal position SKD, SKD1, SKD2 Correlation graph data

Claims

1. A method for manufacturing an energy storage device, comprising a straightening step in which a sealing body that seals the opening of a case containing an electrode body is straightened before a sealing body welding step in which a sealing body is welded to the opening, The surface of the sealing body has a surface that requires the necessary surface positioning accuracy, A database formation step for pre-accumulating correlation graph data between the amount of warpage displacement of the precision-required surface in the front-to-back direction relative to the support point of the sealing body inserted into the opening, and the amount of corrective deformation obtained by correcting the precision-required surface, which has been displaced by the amount of warpage displacement, in the direction opposite to the displacement direction relative to the support point, until it can be restored to a normal position where the amount of warpage displacement becomes zero by its own elastic force. After inserting the sealing body into the opening, a surface displacement measurement step is performed to measure the amount of warpage displacement of the surface requiring precision, The process includes a displacement determination step that determines whether the amount of warpage displacement of the surface requiring accuracy, measured in the surface displacement measurement step, meets a required standard value. In the correction process, if the displacement amount determination step determines that the warpage displacement does not meet the required standard value, a load is applied to the surface requiring accuracy until the corrective deformation occurs at a position where the warpage displacement measured in the surface displacement measurement step matches the warpage displacement in the correlation graph data, and then the load is released. A method for manufacturing energy storage devices.

2. In the method for manufacturing an energy storage device described in claim 1, The aforementioned precision-required surface is a sensor contact surface formed to be in contact with a temperature sensor that monitors the temperature of the energy storage device. A method for manufacturing energy storage devices.

3. In the method for manufacturing an energy storage device according to claim 1 or claim 2, The surface of the sealing body has a plurality of surfaces that require precision, In the surface displacement measurement step, the amount of warpage displacement of each of the surfaces requiring accuracy is measured. In the correction process, if the displacement amount determination process determines that at least one of the warpage displacement amounts does not meet the required standard value, a load is applied to each of the accuracy-requiring surfaces until the average value of the corrective deformation amount occurs when the respective warpage displacement amounts measured in the surface displacement measurement process match the warpage displacement amounts in the correlation graph data, and then the load is released. A method for manufacturing energy storage devices.

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