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 to be within a reference value by changing a correction deformation magnitude in accordance with a surface modulation amount of the sealing body.SOLUTION: In a manufacturing method of an electric storage device 10 having a correction step S6 for correcting a sealing body 12, an accuracy necessary surface 12S is included in the sealing body, and in the case where a surface position MT of the accuracy necessary surface is determined that it is positioned at a rear side from a support point 12K, a surface position of the accuracy necessary surface is previously deformed to a front surface side of the surface position. In a state where the sealing body of which the surface position of the accuracy necessary surface is deformed to the front surface side is inserted into an opening part 111, it is determined whether a surface modulation amount Q against the support point of the accuracy necessary surface satisfies a desired reference value KJ. In a correction step S6, a load F is applied to a rear side to a position where a correction deformation magnitude P obtained by adding the surface deformation amount and an elastic deformation amount DH that sealing body is recovered by own elastic force to a normal position SK where the surface modulation amount becomes zero to the accuracy necessary surface, is generated, in the case where it is determined that the surface modulation amount does not satisfy the reference value, and thereafter, the load is 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, 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 or the like, 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 have a surface displacement amount that is displaced in the front-back direction asymmetrically left and right.

[0003] In this regard, for example, Patent Document 1 and Patent Document 2 disclose a technique 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 substantially as it is to the sealing body to which the current collector terminal is coupled, and the surface displacement amount of the sealing body cannot be sufficiently suppressed. In addition, there is a problem that the surface displacement amount of the sealing body varies depending on the power storage device to be manufactured. Usually, on the surface of the sealing body, for example, there is a surface requiring accuracy where it is necessary to ensure better surface position accuracy than other parts, such as a sensor contact surface formed so as to be in contact with a temperature sensor for monitoring the temperature of the power storage device, and it is necessary to guarantee that the surface position accuracy of the surface requiring accuracy is within a required reference value.

[0006] The present disclosed technology has been made in view of such problems. Even when the surface displacement amount of the sealing body varies depending on the power storage device to be manufactured and the surface displacement amount is left-right asymmetric, the amount of corrective deformation is changed according to the surface displacement amount, and it is an object to provide a method for manufacturing a highly reliable power storage device that can correct the surface requiring accuracy of the 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. A surface position measurement step of measuring the surface position of the precision-required surface in the front-back direction of the sealing body, a surface position determination step of determining whether the surface position of the precision-required surface measured in the surface position measurement step is located on the front surface side or the back surface side with respect to the support point of the sealing body when inserted into the opening, and when it is determined in the surface position determination step that the surface position of the precision-required surface is located on the back surface side with respect to the support point, a surface position change step of displacing the surface position of the precision-required surface to the front surface side with respect to the support point, and the sealing body determined in the surface position determination step that the surface position of the precision-required surface is located on the front surface side with respect to the support point, or the sealing body in which the surface position of the precision-required surface is displaced to the front surface side with respect to the support point in the surface position change step, in a state where it is inserted into the opening, a surface displacement amount measurement step of measuring the surface displacement amount in the front-back direction of the surface position of the precision-required surface with respect to the support point, and a surface displacement amount determination step of determining whether the surface displacement amount measured in the surface displacement amount measurement step satisfies a required reference value. In the correction step, when it is determined in the surface displacement amount determination step that the surface displacement amount does not satisfy the reference value, a load is applied to the back surface side of the sealing body until a correction deformation amount is generated, which is the sum of the surface displacement amount and the elastic deformation amount that the sealing body restores to its normal position where the surface displacement amount becomes zero by its own elastic force, with respect to the precision-required surface, 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 (1) above, it is preferable that the precision-required surface 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 a power storage device according to (1) or (2), the surface of the sealing body has a plurality of surfaces that require accuracy. In the surface position measurement step, the surface positions of the respective surfaces that require accuracy are measured. In the surface position determination step, when it is determined that the surface position of at least one of the surfaces that require accuracy is located on the back surface side with respect to the support point, in the surface position change step, it is preferable to displace the surface positions of all the surfaces that require accuracy to the front surface side with respect to the support point.

[0010] (4) In the method for manufacturing a power storage device according to (1) or (2), the surface of the sealing body has a plurality of surfaces that require accuracy. In the surface displacement amount measurement step, the surface displacement amounts of the respective surfaces that require accuracy are measured. In the correction step, when it is determined in the surface displacement amount determination step that at least one of the surface displacement amounts does not satisfy the required reference value, for each of the surfaces that require accuracy, after applying a load to a position where the average value of the correction deformation amounts obtained by adding the respective surface displacement amounts measured in the surface displacement amount measurement step and the respective elastic deformation amounts occurs, it is preferable to release the load.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

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Figure 5

Figure 6

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Figure 8

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Figure 10

Figure 11

Figure 12

Embodiments for Carrying Out the Invention

[0012] <Overall Description of This Power Storage Device> Next, the overall configuration of the power storage device manufactured by the manufacturing method of the power storage device according to one aspect of the above-disclosed technology will be described in detail with reference to the drawings. FIG. 1 shows a schematic plan view of the power storage device manufactured by the manufacturing method of the power storage device according to one aspect of this embodiment. FIG. 2 shows a schematic cross-sectional view taken along the line A-A 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 a cross-sectional view taken along the line B-B 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.

[0013] As shown in FIGS. 1 to 4, the power storage device 10 manufactured by the manufacturing method of this power storage device includes a case 1, an electrode body 2, and a current collecting terminal 4. Here, 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. However, for the necessity of improving the valve opening performance of the safety valve 124, a material that is softer and easier to deform than the current collecting terminal 4 is used for the sealing body 12.

[0014] Further, in the opening 111 of the case body 11, a 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 a step portion 111S formed at the lower end of the thin portion 111T, which corresponds to the support point 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 is such that it is difficult to prevent the central portion of the sealing body 12 from being displaced (warped) in the front-back direction (Z direction).

[0015] As shown in FIGS. 2 to 4, the electrode body 2 is formed by laminating a positive electrode body 21 and a negative electrode body 22 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.

[0016] The power storage device 10 refers to 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 uses, for example, a lithium transition metal oxide (LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2, LiNiO2, etc.). Also, the metal foil 22K of the negative electrode body 22 uses, for example, a copper foil, and the active material KT2 coated thereon can use, for example, graphite, hard carbon, soft carbon, etc. Further, the separator 23 can use a porous sheet such as polypropylene or polyethylene. Note that a known non-aqueous electrolyte can be used for the electrolyte 8.

[0017] 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 formed integrally.

[0018] The base portion 41 is coupled, for example, by caulking pins 46 or the like to the external connection portions 45 (45A, 45B) located on the surface side of the sealing body 12. Due to an external force when coupling the base portion 41, the external connection portions 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). An insulating member 3 also serving as a sealing material is interposed between the caulking pins 46 and the external connection portions 45 and the sealing body 12. The insulating member 3 can use, for example, polyphenylene sulfide (PPS) resin. When a plurality of the power storage devices 10 are connected to the external connection portions 45 (45A, 45B), a connection bus bar (not shown) is connected thereto.

[0019] Further, the base portion 41 is coupled with the insulating member 3 interposed therebetween to the back surface sides of both end portions 12R in the longitudinal direction (X direction) of the sealing body 12. Further, the base adjacent portion 42 is adjacent to the base portion 41 and is in contact with the insulating member 3. The lead 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, 22K of the non-active material coated portions 211, 221 of the electrode body 2 are in a state of being collectively foiled and are welded and joined to the lead lower end portion 43b. When welding the electrode body 2 and the lead lower end portion 43b, an external force that causes the lead lower end portion 43b to slide or the like with respect to the metal foils 21K, 22K during collective foiling and displaces the lead lower end portion 43b in the longitudinal direction (X direction) of the sealing body 12 is likely to occur. When this external force is propagated to the sealing body 12, the central portion of the sealing body 12 may be displaced in the front-back direction (Z direction).

[0020] Further, the surface 121 of the sealing body 12 has two accuracy-required surfaces 12S (12S1, 12S2) that require the required surface position accuracy. Here, the accuracy-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 present power storage device 10, but it is not necessarily limited to the sensor contact surface 5S. As the temperature sensor 5, for example, a thermistor, a thermocouple, or the like can be used. The temperature sensor 5 is held in a holding case 51 fixed to the mounting bracket 53 and is biased to 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 accuracy-required surfaces 12S (12S1, 12S2) that are the sensor contact surfaces 5S satisfies the required reference value KJ (see FIG. 9).

[0021] When a plurality of the present power storage devices 10 are connected in series to form a battery pack, usually, the long side surfaces 11A and 11B of the case body 11 are arranged close to each other, so the external connection portion 45A of the positive electrode and the external connection portion 45B of the negative electrode are alternately arranged in the same direction. Therefore, the sensor contact surface 5S may be formed on the accuracy-required surface 12S (12S1) closer to the external connection portion 45A of the positive electrode (the case shown in FIG. 2) or on the accuracy-required surface 12S (12S2) closer to the external connection portion 45B of the negative electrode, and it is required that the surface position accuracy of both accuracy-required surfaces 12S (12S1, 12S2) satisfies the required reference value KJ.

[0022] <Manufacturing Method of the Present Power Storage Device> Next, a method for manufacturing 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 method for manufacturing the power storage device shown in FIG. 1. FIG. 6 shows a schematic cross-sectional view representing a measurement method for measuring the surface position of a surface requiring accuracy in the surface position measurement step of the flowchart shown in FIG. 5. FIG. 7 shows a schematic cross-sectional view representing a surface position change method for displacing the surface position of a surface requiring accuracy from a support point to the surface side in the surface position change step of the flowchart shown in FIG. 5. FIG. 8 shows a schematic cross-sectional view representing a measurement method for measuring the surface displacement amount in the front-back direction with respect to the support point of the surface position of a surface requiring accuracy in the surface displacement amount measurement step of the flowchart shown in FIG. 5. FIG. 9 shows a schematic cross-sectional view of a correction device for correcting the surface displacement amount of a surface requiring accuracy within a reference value in the correction step of the flowchart shown in FIG. 5. FIG. 10 shows a schematic cross-sectional view when a load is applied to the correction device shown in FIG. 9 up to a position where a correction deformation amount occurs on a surface requiring accuracy. FIG. 11 shows a schematic cross-sectional view when the load applied to the correction device shown in FIG. 9 up to a position where a correction deformation amount occurs on a surface requiring accuracy is released. FIG. 12 shows an example of correlation graph data representing the correlation between the surface displacement amount and the correction deformation amount of a surface requiring accuracy used in the correction device shown in FIG. 9. In FIGS. 6 to 11, the electrode body 2 is omitted, but as shown in FIG. 2, the electrode body 2 is coupled to the sealing body 12 via the current collecting terminal 4.

[0023] As shown in FIGS. 1 to 12, the method for manufacturing this power storage device is a method for manufacturing a power storage device 10 including a correction step S6 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 S7 of welding the sealing body 12 to the opening 111. The surface 121 of the sealing body 12 has a precision-required surface 12S that requires a required surface position accuracy. And the method for manufacturing this power storage device includes a surface position measurement step S1, a surface position determination step S2, a surface position change step S3, a surface displacement amount measurement step S4, a surface displacement amount determination step S5, a correction step S6, and a sealing body welding step S7. The sealing body welding step S7 is a step of welding the outer peripheral portion of the sealing body 12 determined in the surface displacement amount determination step S5 to satisfy the surface displacement amount Q of the precision-required surface 12S with a reference value KJ, or the outer peripheral portion of the sealing body 12 whose surface displacement amount Q of the precision-required surface 12S is corrected within the reference value KJ in the correction step S6 to the opening 111 by laser welding or the like.

[0024] Here, the precision-required surface 12S will be described by taking as an example a sensor contact surface 5S formed 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 to 12, the sensor contact surface 5S is a flat rectangular surface, and is formed on a precision-required surface 12S (12S1) near the external connection portion 45A of the positive electrode and a precision-required surface 12S (12S2) near the external connection portion 45B of the negative electrode. It is required that the surface position accuracy of both precision-required surfaces 12S (12S1, 12S2) satisfies a required reference value KJ.

[0025] Note that the reference value KJ means the allowable value of the surface displacement amount Q of the surface position of the accuracy-required surface 12S (12S1, 12S2) in the front-back direction (Z direction) of the sealing body 12 with respect to the support point 12K of the sealing body 12. The reference value KJ is, for example, about ±0.2 to 0.3 mm. The displacement of the sealing body 12 to the front surface side (Z direction) is represented by +, and the displacement of the sealing body 12 to the back surface side (Z direction) is represented by -. The reference value KJ shown in FIGS. 9 and 12 is an example when the surface position of the accuracy-required surface 12S (12S1, 12S2) is displaced to the front surface side (Z direction) of the sealing body 12. Since the accuracy-required surface 12S is the sensor contact surface 5S formed so as to be in contact with the temperature sensor 5 that monitors the temperature of the power storage device 10, by setting the surface displacement amount Q (Q1, Q2) of the accuracy-required surface 12S (12S1, 12S2) within the reference value KJ, 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.

[0026] Hereinafter, each step of the manufacturing method of the present power storage device will be described in the order of steps. First, as shown in FIG. 6, in the surface position measurement step S1, the surface position MT of the accuracy-required surface 12S in the front-back direction (Z direction) of the sealing body 12 is measured. Here, before inserting the sealing body 12 into the opening 111, in a state where both end portions in the longitudinal direction (X direction) of the sealing body 12 are supported by a jig (not shown) or the like, the respective surface positions MT (MT1, MT2) of the accuracy-required surface 12S (12S1, 12S2) in the front-back direction (Z direction) of the sealing body 12 are measured. The measuring device 6 for the surface position MT (MT1, MT2) is preferably a non-contact measuring device 6 having, for example, laser rangefinders 61 and 62. The laser rangefinders 61 and 62 irradiate the central portion of the accuracy-required surface 12S (12S1, 12S2) with laser light to measure the height of the surface position MT (MT1, MT2). Note that in the surface position measurement step S1, the surface position MT of the accuracy-required surface 12S may be measured after inserting the sealing body 12 into the opening 111.

[0027] Next, in the surface position determination step S2, the measuring device 6 compares the surface positions MT (MT1, MT2) of each surface 12S (12S1, 12S2) that requires precision measured by the laser distance meters 61 and 62 with the surface position of the reference support point 12K, and determines whether the surface positions MT (MT1, MT2) of the surfaces 12S (12S1, 12S2) that require precision measured in the surface position measurement step S1 are located on the front surface side or the back surface side with respect to the support points 12K (12K1, 12K2) of the sealing body 12 when inserted into the opening 111.

[0028] Then, in the surface position determination step S2, when it is determined that the surface positions MT (MT1, MT2) of the surfaces 12S (12S1, 12S2) that require precision are located on the back surface side with respect to the support points 12K as shown in FIG. 6, in the surface position changing step S3 as shown in FIG. 7, the surface positions MT (MT1, MT2) of the surfaces 12S (12S1, 12S2) that require precision are displaced to the front surface side with respect to the support points 12K. The changing device 6B for the surface positions MT (MT1, MT2) preferably includes, for example, clamping portions 61B1 and 62B1 that clamp the sealing body 12 from the front-back direction (Z direction), and a lifting device that clamps the sealing body 12 at the positions of the surfaces 12S (12S1, 12S2) that require precision by the clamping portions 61B1 and 62B and lifts it to the front surface side of the sealing body 12. When measuring the surface position MT of the surface 12S that requires precision after inserting the sealing body 12 into the opening 111 in the surface position measurement step S1, the changing device 6B for the surface positions MT (MT1, MT2) is preferably a device that can adsorb the surfaces 12S (12S1, 12S2) that require precision of the sealing body 12 and lift it to the front surface side.

[0029] Next, in the surface displacement measurement step S4, as shown in FIG. 8, when it is determined in the surface position determination step S2 that the surface positions MT (MT1, MT2) of the surfaces 12S (12S1, 12S2) requiring accuracy are located on the surface side from the support points 12K (12K1, 12K2) of the sealing body 12, or when the surface positions MT (MT1, MT2) of the surfaces 12S (12S1, 12S2) requiring accuracy are displaced to the surface side from the support points 12K (12K1, 12K2) in the surface position changing step S3, with the sealing body 12 inserted into the opening 111, the surface displacement amounts Q (Q1, Q2) in the front-back direction (Z direction) with respect to the support points 12K (12K1, 12K2) of the surface positions MT (MT1, MT2) of the surfaces 12S (12S1, 12S2) requiring accuracy are measured. The measuring device 6C for the surface displacement amounts Q (Q1, Q2) is preferably a non-contact measuring device 6C having, for example, laser rangefinders 61C and 62C. The laser rangefinders 61C and 62C irradiate the central portions of the surfaces 12S (12S1, 12S2) requiring accuracy with laser light to measure the surface positions MT (MT1, MT2) of the surfaces 12S (12S1, 12S2), and calculate the surface displacement amounts Q (Q1, Q2) in the front-back direction (Z direction) of the surfaces 12S (12S1, 12S2) as the differences from the surface positions of the support points 12K (12K1, 12K2). Then, the measuring device 6C for the surface displacement amounts Q (Q1, Q2) transfers the calculated surface displacement amounts Q (Q1, Q2) to the database of the correcting device 7 shown in FIG. 9. Note that the measuring device 6C for the surface displacement amounts Q (Q1, Q2) may be used in common with the measuring device 6 for the surface positions MT (MT1, MT2).

[0030] Next, in the surface displacement amount determination step S5, it is determined whether or not the surface displacement amount Q (Q1, Q2) measured in the surface displacement amount measurement step S4 satisfies the required reference value KJ. Then, in the correction step S6, when it is determined in the surface displacement amount determination step S5 that the surface displacement amount Q (Q1, Q2) does not satisfy the reference value KJ, as shown in FIG. 10, the operating parts 71 and 72 of the correction device 7 operate, and with respect to the surface 12S (12S1, 12S2) that requires accuracy, a correction deformation amount P (P1, P2) obtained by adding the surface displacement amount Q (Q1, Q2) and the elastic deformation amount DH (DH1, DH2) for restoring the sealing body 12 to the normal position SK where the surface displacement amount Q becomes zero by its own elastic force is generated. After applying a load F (F1, F2) to the back surface side of the sealing body 12 until the position, as shown in FIG. 11, the operating parts 71 and 72 of the correction device 7 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 their movement amounts. Note that the operating parts 71 and 72 of the correction device 7 may repeat the correction deformation and release in multiple times and gradually increase the deformation amount until a predetermined correction deformation amount P (P1, P2) is reached.

[0031] As described above, according to the manufacturing method of this power storage device, in the surface position measurement step S1, the surface position MT of the surface 12S that requires accuracy in the front-back direction (Z direction) of the sealing body 12 is measured, and in the surface position determination step S2, when it is determined that the surface position MT is located on the back surface side of the support point 12K of the sealing body 12 when inserted into the opening 111, in the surface position change step S3, the surface position MT of the surface 12S that requires accuracy is displaced to the front surface side of the support point 12K. Therefore, even if the warping direction of the sealing body 12 changes for each power storage device 10 to be manufactured, for all the sealing bodies 12, the surface position MT of the surface 12S that requires accuracy can be unified to be displaced to the front surface side of the support point 12K once.

[0032] Further, in the correction step S6, when it is determined in the surface displacement amount determination step S5 that the surface displacement amount Q does not satisfy the reference value KJ, a correction deformation amount P obtained by adding the surface displacement amount Q and the elastic deformation amount DH for restoring the sealing body 12 to the normal position SK where the surface displacement amount Q becomes zero by its own elastic force is applied to the surface of the sealing body 12. After applying a load F to the back surface side of the sealing body 12 up to the position where the correction deformation amount P occurs, the load F is released. Therefore, before welding the sealing body 12 to the opening 111, the correction can be performed on the required precision surface 12S where the surface displacement amount Q does not satisfy the required reference value KJ. Further, since the load F is applied to the required precision surface 12S from the front surface side to the back surface side of the sealing body 12, it is not necessary to apply the load F from the back surface side to the front surface side of the sealing body 12, and the required precision surface 12S can be easily and stably corrected within the reference value KJ.

[0033] Further, in the correction step S6, a load F is applied to the back surface side of the sealing body 12 up to the position where a correction deformation amount P obtained by adding the surface displacement amount Q and the elastic deformation amount DH for restoring the sealing body 12 to the normal position SK where the surface displacement amount Q becomes zero by its own elastic force occurs with respect to the required precision surface 12S, and then the load F is released. Therefore, the plastic deformation amount SH with respect to the corrected required precision surface 12S coincides with the surface displacement amount Q of the required precision surface 12S, and the required precision surface 12S can be accurately corrected.

[0034] Incidentally, the elastic deformation amount DH (DH1, DH2) that restores the sealing body 12 to the normal position SK where the surface displacement amount Q is zero by its own elastic force can be mechanically calculated using, for example, CAE (Computer Aided Engineering) analysis. However, it is necessary to calculate it every time the surface displacement amount Q (Q1, Q2) changes, which becomes complicated. Therefore, the surface displacement amount Q in the front-back direction (Z direction) of the accuracy-required surface 12S (12S1, 12S2), and the correction deformation amount P that corrects and deforms the accuracy-required surface 12S (12S1, 12S2) displaced by the surface displacement amount Q to the position where it can be restored to the normal position SK by its own elastic force in the direction opposite to the displacement direction and the front-back direction (Z direction) of the accuracy-required surface 12S (12S1, 12S2), the correlation graph data SKD representing the correlation relationship is preferably created in advance as shown in FIG. 12 and stored in the database of the correction device 7. In this case, without calculating the elastic deformation amount DH (DH1, DH2) one by one, in the correlation graph data SKD (SKD1, SKD2), the correction deformation amount P (P1, P2) of the point where the surface displacement amount Q (Q1, Q2) of the accuracy-required surface 12S (12S1, 12S2) measured in the surface displacement amount measurement step S4 coincides can be obtained.

[0035] This correlation graph data SKD is created, for example, by the following procedure. First, the sealing body 12 to which the electrode body 2 is coupled via the current collecting terminal 4 is inserted into the opening 111 of the case body 11. Next, the respective surface positions of the accuracy-required surface 12S (12S1, 12S2) of the sealing body 12 in the front-back direction (Z direction) of the sealing body 12 are measured. The surface displacement amount Q in the front-back direction (Z direction) is calculated as the difference between the measured surface positions of each accuracy-required surface 12S (12S1, 12S2) and the surface position of the reference support point 12K. Then, the respective surface positions of the accuracy-required surface 12S (12S1, 12S2) of the sealing body 12 with different surface displacement amounts Q are measured, and various surface displacement amounts Q are stored in the database of the correction device 7.

[0036] Next, as shown in FIG. 10, the actuating portions 71 and 72 of the correcting device 7 operate to apply a load F in the direction opposite to the displacement direction (Z direction) of the precision-required surfaces 12S (12S1, 12S2) which have been displaced by the respective surface displacement amounts Q to a position where they can be restored to the normal position SK by their own elastic forces, and correctively deform them. Then, as shown in FIG. 11, the actuating portions 71 and 72 are returned to their original positions to release the load F. And, as shown in FIG. 12, the correcting device 7 creates correlation graph data SKD (SKD1, SKD2) between the initial surface displacement amount Q and the correction deformation amount P at the time of corrective deformation, and stores it in a database. Here, although the correlation graph data SKD (SKD1, SKD2) shown in FIG. 12 is displayed as a line graph, it may be displayed as a curve graph by increasing the measurement data. Note that the correction deformation amount P (P1, P2) is the deformation amount by which the precision-required surfaces 12S (12S1, 12S2) displaced by the surface displacement amount Q (Q1, Q2) can be restored to the normal position SK where the surface displacement amount Q becomes zero by their own elastic forces, and thus coincides with the sum of the elastic deformation amount DH (DH1, DH2) and the plastic deformation amount SH (SH1, SH2) corresponding to the surface displacement amount Q (Q1, Q2) before correction.

[0037] Therefore, even when the surface displacement amounts Q (Q1, Q2) of the precision-required surfaces 12S (12S1, 12S2) are different for each power storage device 10 to be manufactured and the surface displacement amounts Q (Q1, Q2) are left-right asymmetric, an appropriate correction deformation amount P (P1, P2) can be easily obtained according to the surface displacement amounts Q (Q1, Q2) of the correlation graph data SKD (SKD1, SKD2) shown in FIG. 12. Note that since the correlation graph data SKD (SKD1, SKD2) differs depending on the size, type, etc. of the power storage device 10, it is preferable to create the correlation graph data SKD (SKD1, SKD2) in advance for each power storage device 10 and accumulate it in a database.

[0038] 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 S6 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 S7 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. A surface position measurement step S1 of measuring a surface position MT of the precision-required surface 12S in the front-back direction (Z direction) of the sealing body 12, a surface position determination step S2 of determining whether the surface position MT of the precision-required surface 12S measured in the surface position measurement step S1 is located on the front surface side or the back surface side with respect to a support point 12K of the sealing body 12 when inserted into the opening 111, a surface position change step S3 of displacing the surface position MT of the precision-required surface 12S to the front surface side with respect to the support point 12K when it is determined in the surface position determination step S2 that the surface position MT of the precision-required surface 12S is located on the back surface side with respect to the support point 12K, a surface displacement amount measurement step S4 of measuring a surface displacement amount Q in the front-back direction (Z direction) of the surface position MT of the precision-required surface 12S with respect to the support point 12K in a state where the sealing body 12 determined in the surface position determination step S2 that the surface position MT of the precision-required surface 12S is located on the front surface side with respect to the support point 12K or the sealing body 12 in which the surface position MT of the precision-required surface 12S is displaced to the front surface side with respect to the support point 12K in the surface position change step S3 is inserted into the opening 111, and a surface displacement amount determination step S5 of determining whether the surface displacement amount Q measured in the surface displacement amount measurement step S4 satisfies a required reference value KJ. In the correction step S6, when it is determined in the surface displacement amount determination step S5 that the surface displacement amount Q does not satisfy the reference value KJ, a load F is applied to the back surface side until a correction deformation amount P is generated, which is the sum of the surface displacement amount Q and an elastic deformation amount DH that allows the sealing body 12 to restore itself to a normal position SK where the surface displacement amount Q becomes zero, with respect to the precision-required surface 12S, and then the load F is released. This is a method for manufacturing a power storage device.

[0039] Therefore, according to the method for manufacturing the present power storage device 10, the surface displacement amount Q of the sealing body 12 varies for each power storage device 10 to be manufactured. Even when the surface displacement amount Q is asymmetric left and right, the correction deformation amount P can be changed according to the surface 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.

[0040] Further, in the method for manufacturing the power storage device, the surface 121 of the sealing body 12 has a plurality of surfaces requiring precision (12S1, 12S2). In the surface position measurement step S1, the surface positions MT (MT1, MT2) of the respective surfaces requiring precision 12S (12S1, 12S2) are measured. In the surface position determination step S2, when it is determined that the surface position MT (MT1, MT2) of at least one surface requiring precision 12S (12S1, 12S2) is located on the back side of the support points 12K (12K1, 12K2), in the surface position changing step S3, it is preferable to displace the surface positions MT of all the surfaces requiring precision 12S to the front side of the support points 12K (12K1, 12K2).

[0041] In this case, even if there are a plurality of surfaces requiring precision 12S (12S1, 12S2), when it is determined in the surface position determination step S2 that the surface position MT (MT1, MT2) of at least one surface requiring precision 12S (12S1, 12S2) is located on the back side of the support points 12K (12K1, 12K2), in the surface position changing step S3, the surface positions MT (MT1, MT2) of all the surfaces requiring precision 12S (12S1, 12S2) are displaced to the front side of the support points 12K (12K1, 12K2). Therefore, even if the plurality of surfaces requiring precision 12S (12S1, 12S2) are displaced in different front-back directions (Z direction), in the surface position changing step S3, the surface positions MT of all the surfaces requiring precision 12S can be displaced to the front side of the support points 12K.

[0042] Therefore, in the surface position changing step S3, it is possible to simplify the changing device 6B for displacing the surfaces requiring precision 12S (12S1, 12S2), and in the correction step S6, it is possible to simplify the correction device 7 for applying a load F (F1, F2) to the surfaces requiring precision 12S (12S1, 12S2). As a result, 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.

[0043] Also, in the method for manufacturing the present 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 S4, the surface displacement Q (Q1B, Q2) of each surface requiring precision 12S (12S1, 12S2) is measured. In the correction step S6, when it is determined in the surface displacement determination step S5 that at least one surface displacement Q (Q2) does not satisfy the required reference value KJ, for each surface requiring precision 12S (12S1, 12S2), the load F (F1, F2) is applied until the average value (P1B + P2) × 1 / 2 of the correction deformation amount P (P1B, P2) obtained by adding the respective surface displacement Q (Q1B, Q2) measured in the surface displacement measurement step S4 and the respective elastic deformation amounts DH (DH1, DH2) occurs, and then the load F (F1, F2) is preferably released.

[0044] In this case, even if there are a plurality of surfaces requiring precision 12S (12S1, 12S2), after applying the load F (F1, F2) until the average value (P1B + P2) × 1 / 2 of the correction deformation amount P (P1B, P2) obtained by adding the respective surface displacement Q (Q1B, Q2) measured in the surface displacement measurement step S4 and the respective elastic deformation amounts DH (DH1, DH2) occurs, 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.

[0045] <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

[0046] 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 DH, DH1, DH2 Elastic deformation amount F, F1, F2 Load KJ Reference value MT, MT1, MT2 Surface position P, P1, P1B, P2 Correction deformation amount Q, Q1, Q1B, Q2 Surface displacement amount S1 Surface position measurement process S2 Surface position determination process S3 Surface position change process S4 Surface displacement amount measurement process S5 Surface displacement amount determination process S6 Correction process S7 Sealing body welding process SK Normal position SKD, SKD1, SKD2 Correlation graph data

Claims

1. A method for manufacturing a power storage device, comprising 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, wherein the surface of the sealing body has a precision-required surface that requires a required surface position accuracy, a surface position measurement step of measuring the surface position of the precision-required surface in the front-back direction of the sealing body, a surface position determination step of determining whether the surface position of the precision-required surface measured in the surface position measurement step is located on the front surface side or the back surface side with respect to a support point of the sealing body when inserted into the opening, a surface position change step of displacing the surface position of the precision-required surface to the front surface side with respect to the support point when it is determined in the surface position determination step that the surface position of the precision-required surface is located on the back surface side with respect to the support point, a surface displacement amount measurement step of measuring the surface displacement amount in the front-back direction of the surface position of the precision-required surface with respect to the support point in a state where the sealing body determined in the surface position determination step that the surface position of the precision-required surface is located on the front surface side with respect to the support point, or the sealing body whose surface position of the precision-required surface has been displaced to the front surface side with respect to the support point in the surface position change step, is inserted into the opening, and a surface displacement amount determination step of determining whether the surface displacement amount measured in the surface displacement amount measurement step satisfies a required reference value, wherein in the correction step, when it is determined in the surface displacement amount determination step that the surface displacement amount does not satisfy the reference value, a load is applied to the back surface side of the sealing body until a correction deformation amount, which is the sum of the surface displacement amount and an elastic deformation amount that allows the sealing body to restore itself to a normal position where the surface displacement amount becomes zero by its own elastic force, occurs at the precision-required surface, and then the load is released A method for manufacturing a power storage device.

2. In the method for manufacturing a power storage device according to Claim 1, the precision-required surface is a sensor contact surface formed so as to be in contact with a temperature sensor for monitoring the temperature of the power storage device A method for manufacturing a power storage device.

3. In the method for manufacturing a power storage device according to Claim 1 or Claim 2, the surface of the sealing body has a plurality of the precision-required surfaces, in the surface position measurement step, the surface positions of the respective precision-required surfaces are measured, and in the surface position change step, when it is determined in the surface position determination step that the surface position of at least one of the precision-required surfaces is located on the back surface side with respect to the support point, the surface positions of all the precision-required surfaces are displaced to the front surface side with respect to the support point A method for manufacturing a power storage device.

4. In the method for manufacturing a power storage device according to claim 1 or claim 2, the surface of the sealing body has a plurality of required precision surfaces, in the surface displacement measurement step, the surface displacement of each of the required precision surfaces is measured, in the correction step, when it is determined in the surface displacement determination step that at least one of the surface displacements does not satisfy a required reference value, for each of the required precision surfaces, a load is applied until an average value of the correction deformation amounts obtained by adding the respective surface displacements measured in the surface displacement measurement step and the respective elastic deformation amounts occurs, and then the load is released A method for manufacturing a power storage device.

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