JP6922328B2 - Manufacturing method of electrode assembly - Google Patents

Description

The present invention relates to a method for manufacturing an electrode assembly.

For example, in Patent Document 1, a sheet-shaped positive electrode and a sheet-shaped negative electrode are laminated via a sheet-shaped separator, and a group of laminated electrode tabs of the positive electrode and a group of laminated electrode tabs of the negative electrode are laminated using a welding jig. The technique of joining is described. In this welding jig, the positioning guide makes contact with the side side of the laminated body to position the laminated body and suppress the occurrence of misalignment.

Japanese Unexamined Patent Publication No. 2000-251882

However, there are variations due to manufacturing tolerances in the size of the electrodes, the size of the tabs, the position of forming the tabs, and the like. Therefore, even if the laminated body is positioned as in the welding jig described in Patent Document 1, the position of the tab in the direction intersecting the laminating direction may deviate from the design position. When the tab laminate is welded by laser welding, it is desirable that the irradiation position of the laser beam is predetermined and the edge of the tab is irradiated with the laser beam. Therefore, if the position of the edge of the tab included in the tab laminate is significantly deviated from the irradiation position, good welding may not be possible.

The present invention provides a method for manufacturing an electrode assembly capable of improving the welding accuracy of a tab laminate.

The method for manufacturing an electrode assembly according to one aspect of the present invention is a method for manufacturing an electrode assembly having a plurality of electrodes, each including a tab. This manufacturing method includes a step of preparing a tab laminate in which tabs of a plurality of electrodes are laminated in the first direction, a step of measuring the positions of both ends of the tab laminate in a second direction intersecting the first direction, and a step of measuring the positions of both ends of the tab laminate. The tab stacking is performed by calculating the center position of the tab laminate in the second direction based on the positions of both ends and irradiating the irradiation position in the second direction determined according to the center position with an energy beam for welding. A step of forming a welded portion on an end face in a second direction of the body is provided.

In this method of manufacturing the electrode assembly, the irradiation position of the energy beam for welding in the second direction is determined according to the center position of the tab laminate in the second direction. Since the center position of the tab laminate is in the middle of the positions of both ends in the second direction of the tab laminate, it is the edge of the tab included in the tab laminate that is most displaced in one of the second directions. , It is also an intermediate position with the edge of the tab that is most displaced to the other in the second direction. Therefore, by setting the irradiation position with reference to the center position of the tab laminate, it is possible to reduce the amount of deviation of the edge of the tab from the irradiation position. As a result, it is possible to improve the welding accuracy of the tab laminate.

The reference center position, which is the design center position in the second direction of the tab laminate, and the reference irradiation position, which is the design irradiation position in the second direction of the energy beam, may be predetermined. The irradiation position may be set to a position where the reference irradiation position is shifted according to the distance between the reference center position and the center position of the tab laminate. As described above, the center position of the tab laminate is the edge of the tab contained in the tab laminate that is most displaced in one of the second directions and the tab that is most displaced in the other in the second direction. It is an intermediate position with the edge of. Therefore, by setting the irradiation position at a position deviated from the reference irradiation position by the distance that the center position of the tab laminate is deviated from the reference center position, the maximum amount of deviation of the edge of the tab from the irradiation position is set. Can be equalized at both ends of the tabbed laminate in the second direction. As a result, the amount of deviation of the edge of the tab from the irradiation position can be reduced, and the welding accuracy of the tab laminate can be improved.

The method for manufacturing the electrode assembly may further include a step of placing the protective plate on the tab laminate so that the center position of the protective plate in the second direction is aligned with the center position of the tab laminate. In the forming step, a welded portion may be formed over the protective plate and the end face. In this case, the energy beam is irradiated after the protective plate is placed on the tab laminate. As a result, it is possible to prevent the tabs of the tab stack from being peeled off due to the heat of the energy beam.

The method for manufacturing the electrode assembly includes a step of calculating the length of the tab laminate along the second direction based on the positions of both ends and a step of confirming the laminated state of the tab laminate based on the above length. , May be further provided. In the step of forming, a welded portion may be formed on the end face of the tab laminate determined to be in a normal laminated state. The large length of the tab laminate along the second direction means that the positional deviation (stacking deviation) between the plurality of tabs included in the tab laminate in the second direction is large. When the stacking deviation of the tab laminate is large, even if the irradiation position is set with reference to the center position of the tab laminate, the deviation amount of the edge of the tab from the irradiation position may not be sufficiently reduced. be. In such a case, if the energy beam is irradiated to the irradiation position, welding failure may occur. Therefore, it is possible to reduce the occurrence of welding defects by forming a welded portion on the end face of the tab laminate determined to be in a normal laminated state.

According to the present invention, the welding accuracy of the tab laminate can be improved.

It is an exploded perspective view which shows the power storage device manufactured by using the manufacturing method of the electrode assembly which concerns on one Embodiment. It is sectional drawing along the line II-II of FIG. It is a perspective view of the electrode assembly shown in FIG. It is a process drawing which shows an example of the manufacturing method of an electrode assembly. It is a figure which shows one step of the manufacturing method of the electrode assembly shown in FIG. It is a figure which shows one step of the manufacturing method of the electrode assembly shown in FIG. It is a figure which shows one step of the manufacturing method of the electrode assembly shown in FIG. (A) is a diagram for explaining the irradiation position in the manufacturing method of the electrode assembly of the comparative example, and (b) is a diagram for explaining the irradiation position in the manufacturing method of the electrode assembly shown in FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same reference numerals are used for the same or equivalent elements, and duplicate description is omitted.

FIG. 1 is an exploded perspective view showing a power storage device manufactured by using the method for manufacturing an electrode assembly according to an embodiment. FIG. 2 is a cross-sectional view taken along the line II-II of FIG. The power storage device 1 shown in FIGS. 1 and 2 is configured as a non-aqueous electrolyte secondary battery such as a lithium ion secondary battery.

The power storage device 1 includes, for example, a case 2 having a substantially rectangular parallelepiped shape and an electrode assembly 3 housed in the case 2. The case 2 is made of a metal such as aluminum. The case 2 has a main body portion 2a opened on one side and a lid portion 2b that closes the opening of the main body portion 2a. Although not shown, a non-aqueous (organic solvent-based) electrolytic solution is injected into the case 2, for example. The positive electrode terminal 4 and the negative electrode terminal 5 are arranged apart from each other on the lid portion 2b of the case 2. The positive electrode terminal 4 is fixed to the case 2 via the insulating ring 6, and the negative electrode terminal 5 is fixed to the case 2 via the insulating ring 7. Further, an insulating film F is arranged between the electrode assembly 3 and the inner side surface and the bottom surface of the case 2, and the insulating film F insulates the case 2 from the electrode assembly 3. The lower end of the electrode assembly 3 is in contact with the inner bottom surface of the case 2 via the insulating film F. By arranging the spacer SP between the electrode assembly 3 and the case 2, the gap between the electrode assembly 3 and the case 2 is filled.

The electrode assembly 3 has a plurality of sheet-shaped positive electrodes 8 each having a tab 14b, and a plurality of sheet-shaped negative electrodes 9 each having a tab 16b. In the electrode assembly 3, a plurality of positive electrodes 8 and a plurality of negative electrodes 9 are alternately laminated via a bag-shaped separator 10. The positive electrode 8 is wrapped in a bag-shaped separator 10. The positive electrode 8 in a state of being wrapped in the bag-shaped separator 10 is configured as a positive electrode 11 with a separator. Therefore, the electrode assembly 3 has a structure in which a plurality of positive electrodes 11 with separators and a plurality of negative electrodes 9 are alternately laminated. The electrodes located at both ends of the electrode assembly 3 are negative electrodes 9.

The positive electrode 8 has, for example, a metal foil 14 which is a positive electrode current collector made of aluminum foil, and a positive electrode active material layer 15 formed on both sides of the metal foil 14. The metal foil 14 has a main body portion 14a having a rectangular shape in a plan view and a tab 14b integrated with the main body portion 14a. The tab 14b projects from the upper edge of the main body 14a. The tab 14b penetrates the separator 10. The tab 14b is connected to the positive electrode terminal 4 via the conductive member 12. The plurality of stacked tabs 14b are arranged between the conductive member 12 and the protective plate 23 thinner than the conductive member 12 (see FIG. 3). The protective plate 23 is formed in a rectangular flat plate shape from the same material as the metal foil 14 of the positive electrode 8, for example.

The positive electrode active material layer 15 is formed on both the front and back surfaces of the main body portion 14a. The positive electrode active material layer 15 is a porous layer formed by containing the positive electrode active material and the binder. Examples of the positive electrode active material include composite oxides, metallic lithium, sulfur and the like. Composite oxides include, for example, at least one of manganese, nickel, cobalt and aluminum and lithium.

The negative electrode 9 has, for example, a metal foil 16 which is a negative electrode current collector made of copper foil, and a negative electrode active material layer 17 formed on both sides of the metal foil 16. The metal foil 16 has a main body portion 16a having a rectangular shape in a plan view and a tab 16b integrated with the main body portion 16a. The tab 16b projects from the upper edge of the main body 16a. The tab 16b is connected to the negative electrode terminal 5 via the conductive member 13. The plurality of stacked tabs 16b are arranged between the conductive member 13 and the protective plate 25 thinner than the conductive member 13 (see FIG. 3). The protective plate 25 is formed in a rectangular flat plate shape from, for example, the same material as the metal foil 16 of the negative electrode 9.

The negative electrode active material layer 17 is formed on both the front and back surfaces of the main body portion 16a. The negative electrode active material layer 17 is a porous layer formed by containing the negative electrode active material and the binder. Examples of the negative electrode active material include graphite, highly oriented graphite, mesocarbon microbeads, carbon such as hard carbon and soft carbon, alkali metals such as lithium and sodium, metal compounds, and SiOx (0.5 ≦ x ≦ 1.5). ) And other metal oxides or boron-added carbon and the like.

The separator 10 has a rectangular shape in a plan view. Examples of the material for forming the separator 10 include a porous film made of a polyolefin resin such as polyethylene (PE) and polypropylene (PP), or a woven cloth or non-woven fabric made of polypropylene, polyethylene terephthalate (PET), methyl cellulose and the like. ..

FIG. 3 is a perspective view of the electrode assembly shown in FIG. As shown in FIG. 3, in the electrode assembly 3, the assembly main body 20 in which a plurality of positive electrodes 8 and a plurality of negative electrodes 9 are alternately laminated via a separator 10 and tabs 14b of the plurality of positive electrodes 8 are laminated. It has a tab laminate 21 and a tab laminate 22 in which tabs 16b of a plurality of negative electrodes 9 are laminated.

The tab laminates 21 and 22 project from one side surface of the assembly main body 20 in the X-axis direction. The X-axis direction intersects (here, orthogonal) with the longitudinal direction of the assembly main body 20 (Y-axis direction (second direction)) and the stacking direction of the positive electrode 8 and the negative electrode 9 (Z-axis direction (first direction)). The direction. The tab laminates 21 and 22 are arranged apart from each other in the Y-axis direction.

The tab laminate 21 has two side surfaces 21a (end surfaces), a front end surface 21b, and an upper surface 21c. The front end surface 21b and the upper surface 21c connect the side surfaces 21a. The tab 14b is not provided with the positive electrode active material layer 15. Further, the number of tabs 14b constituting the tab laminate 21 is about half the number of electrodes constituting the electrode assembly 3. Therefore, the tip surface 21b of the tab laminate 21 formed by laminating the tabs 14b according to the height of one side surface of the assembly main body 20 becomes thinner toward the tip of the tab laminate 21. It is an inclined surface like this. The tab laminate 21 is placed on the conductive member 12. A protective plate 23 is placed on the upper surface 21c of the tab laminate 21. Therefore, the tab laminate 21 is sandwiched by the conductive member 12 and the protective plate 23 in the Z-axis direction.

The thickness of the conductive member 12 is larger than the thickness of the tab 14b. The thickness of the protective plate 23 is larger than the thickness of the tab 14b, but smaller than the thickness of the conductive member 12. The length of the conductive member 12 in the Y-axis direction is larger than the length of the tab laminate 21 in the Y-axis direction. The tip position of the tab laminate 21 coincides with the edge portion of the conductive member 12. The length of the protective plate 23 in the Y-axis direction is equal to the length of the tab laminate 21 in the Y-axis direction. The materials of the conductive member 12 and the protective plate 23 are the same as those of the metal foil 14.

The two side surfaces 21a of the tab laminate 21 are provided with welded portions 24 in which the tabs 14b of the tab laminate 21 are welded to each other. The welded portion 24 extends from the protective plate 23 to the conductive member 12. The welded portion 24 is formed by laser welding.

The tab laminate 22 has two side surfaces 22a (end surfaces), a front end surface 22b, and an upper surface 22c. The front end surface 22b and the upper surface 22c connect the side surfaces 22a. The tab 16b is not provided with the negative electrode active material layer 17. Further, the number of tabs 16b constituting the tab laminate 22 is about half the number of electrodes constituting the electrode assembly 3. Therefore, the tip surface 22b of the tab laminate 22 formed by laminating the tabs 16b according to the height of one side surface of the assembly main body 20 becomes thinner toward the tip of the tab laminate 22. It is an inclined surface like this. The tab laminate 22 is placed on the conductive member 13. A protective plate 25 is placed on the upper surface 22c of the tab laminate 22. Therefore, the tab laminate 22 is sandwiched in the Z-axis direction by the conductive member 13 and the protective plate 25.

The thickness of the conductive member 13 is larger than the thickness of the tab 16b. The thickness of the protective plate 25 is larger than the thickness of the tab 16b, but smaller than the thickness of the conductive member 13. The length of the conductive member 13 in the Y-axis direction is larger than the length of the tab laminate 22 in the Y-axis direction. The tip position of the tab laminate 22 coincides with the edge of the conductive member 13. The length of the protective plate 25 in the Y-axis direction is equal to the length of the tab laminate 22 in the Y-axis direction. The materials of the conductive member 13 and the protective plate 25 are the same as those of the metal foil 16.

The two side surfaces 22a of the tab laminate 22 are provided with welded portions 26 in which the tabs 16b of the tab laminate 22 are welded to each other. The welded portion 26 extends from the protective plate 25 to the conductive member 13. The welded portion 26 is formed by laser welding.

Next, a method of manufacturing the electrode assembly 3 will be described with reference to FIGS. 4 to 7. FIG. 4 is a process diagram showing an example of a method for manufacturing an electrode assembly. 5 to 7 are views showing one step of the method for manufacturing the electrode assembly shown in FIG. 4. Although FIGS. 5 to 7 show only the configuration in which the tabs 14b of the plurality of positive electrodes 8 are welded to each other, the same applies to the configuration in which the tabs 16b of the plurality of negative electrodes 9 are welded to each other.

As shown in FIG. 4, the manufacturing method M includes steps S01 to S07. This manufacturing method M is carried out using an electrode welding apparatus 30 (see FIGS. 5 to 7). The electrode welding device 30 includes a measuring instrument 31, a transport device 32, an irradiation device 33, and a controller 34 (see FIGS. 5 to 7). Note that, in FIGS. 5 to 7, only the components used in each step are shown among the components of the electrode welding apparatus 30. The controller 34 is composed of a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), an input / output interface, and the like. The controller 34 controls the measuring instrument 31, the transport device 32, and the irradiation device 33.

First, in step S01, the assembly main body 20 having the main bodies 14a and 16a laminated in the Z-axis direction, the tab laminate 21 having the tabs 14b laminated in the Z-axis direction, and the tab laminate 21 having the tabs 14b laminated in the Z-axis direction were laminated in the Z-axis direction. A tab laminate 22 having tabs 16b and the like are prepared. For example, first, the tabs 14b are laminated on the conductive member 12, and the laminated tabs 14b are pressed toward the conductive member 12 from the side opposite to the conductive member 12 by a jig (not shown). As a result, the tabs 14b adjacent to each other in the Z-axis direction come into contact with each other to form the tab laminate 21. Similarly, the tabs 16b are laminated on the conductive member 13, and the laminated tabs 16b are pressed toward the conductive member 13 from the side opposite to the conductive member 13 by a jig (not shown). As a result, the tabs 16b adjacent to each other in the Z-axis direction come into contact with each other to form the tab laminate 22.

Subsequently, in step S02, the positions of the ends 21d and 21e and the positions of the ends 22d and 22e are measured. The ends 21d and 21e are both ends of the tab laminate 21 in the Y-axis direction. The ends 22d and 22e are both ends of the tab laminate 22 in the Y-axis direction. As shown in FIG. 5, the measuring instrument 31 is used to measure the positions of the ends 21d and 21e and the positions of the ends 22d and 22e. As the measuring instrument 31, for example, a laser displacement meter is used. In this case, the measuring instrument 31 sequentially measures the thickness of the measurement target along the Y-axis direction, and specifies the positions of the ends 21d, 21e, 22d, and 22e based on the change in the thickness.

For example, the origin in the Y-axis direction is predetermined, and the distance from the origin to each end 21d, 21e, 22d, 22e is measured as the position (Y-axis coordinate) of each end 21d, 21e, 22d, 22e. NS. The measuring instrument 31 transmits the measured measured value to the controller 34. The positions of the 21d, 21e, 22d, and 22e may be directly measured by the measuring instrument 31, or may be calculated by the controller 34 based on the measured values of the measuring instrument 31. Further, the measuring instrument 31 may be a camera.

Subsequently, in step S03, the tab width of the tab laminates 21 and 22 is calculated. The tab width is a length along the Y-axis direction of the tab laminate. As shown in FIG. 5, the controller 34 calculates the tab width Wp based on the position Pp1 at the end 21d and the position Pp2 at the end 21e. The tab width Wp is a length along the Y-axis direction of the tab laminate 21. Specifically, the controller 34 calculates the difference between the position Pp1 and the position Pp2, and sets the calculation result as the tab width Wp.

Subsequently, in step S04, the laminated state of the tab laminated bodies 21 and 22 is confirmed based on the tab width. For example, the stacking state may be confirmed based on the amount of stacking deviation in the Y-axis direction. In this case, first, the controller 34 calculates the stacking deviation amount from the tab width Wp and the reference tab width. The reference tab width is a tab of a tab laminate 21 in which a plurality of tabs 14b having a width (length along the Y-axis direction) according to a design value are laminated in the Z-axis direction without shifting in the Y-axis direction. The width is the same as the above design value. Specifically, the controller 34 subtracts the reference tab width from the tab width Wp, and uses the subtraction result as the stacking deviation amount.

Then, the controller 34 compares the stacking deviation amount with the predetermined value. The predetermined value is the maximum value of the amount of stacking deviation that does not cause welding defects. When the controller 34 determines that the stacking deviation amount is larger than a predetermined value, it determines that the laminated state of the tab laminated body is abnormal, and information indicating that the electrode assembly 3 including the tab laminated body is abnormal. Is output. The controller 34 may display the abnormality of the electrode assembly 3 by outputting the information to, for example, a display (not shown). If it is determined that the laminated state of the tab laminated body is abnormal, the subsequent steps S05 to S07 are not carried out. On the other hand, when the controller 34 determines that the stacking deviation amount is equal to or less than a predetermined value, it determines that the stacking state of the tab laminate is normal, and performs the next step S05.

Even if the controller 34 confirms the laminated state of the tab laminated bodies 21 and 22 by comparing the allowable tab width obtained by adding the above predetermined value to the reference tab width with the tab width of the tab laminated bodies 21 and 22. good. In this case, when the tab width of the tab laminates 21 and 22 is larger than the allowable tab width, the controller 34 determines that the laminated state of the tab laminates is abnormal, and determines that the tab widths of the tab laminates 21 and 22 are abnormal. When is less than or equal to the allowable tab width, it is determined that the laminated state of the tab laminated body is normal.

Further, the controller 34 calculates the distances from the reference center position Cr to the position Pp1 and the position Pp2, which will be described later, and subtracts half the value of the reference tab width from the calculated distances to reduce the amount of deviation of the ends 21d and 21e. Each may be calculated. Then, the controller 34 may confirm the laminated state of the tab laminated bodies 21 and 22 by comparing the total value of these deviation amounts with the predetermined value. In this case, when the controller 34 determines that the total value is larger than the predetermined value, it determines that the laminated state of the tab laminate is abnormal, and when the total value is equal to or less than the predetermined value, the tab laminate It is determined that the laminated state is normal.

Subsequently, in step S05, the center position of the tab laminates 21 and 22 in the Y-axis direction is calculated. As shown in FIG. 5, the controller 34 calculates the center position Cp of the tab stack 21 in the Y-axis direction based on the position Pp1 of the end 21d and the position Pp2 of the end 21e. Specifically, the controller 34 adds the position Pp1 and the position Pp2, and sets half the value of the addition result as the center position Cp.

Subsequently, in step S06, the protective plates 23 and 25 are placed on the tab laminates 21 and 22, respectively. Specifically, as shown in FIG. 6, the controller 34 controls the transport device 32, and the transport device 32 transports the protective plate 23. The transport device 32 is provided with a suction pad, and transports the protective plate 23 while holding the protective plate 23 by suction. Then, the transport device 32 places the protective plate 23 on the tab laminated body 21 (upper surface 21c) so that the central position Cb of the protective plate 23 in the Y-axis direction is aligned with the central position Cp of the tab laminated body 21.

Subsequently, in step S07, the welded portions 24 and 26 are formed. Specifically, as shown in FIG. 7, the controller 34 causes the irradiation device 33 to irradiate the irradiation energy beams B for welding at the irradiation positions Pb1 and Pb2 determined according to the center position Cp. Control. The irradiation device 33 is a scanner head including, for example, a lens and a galvanometer mirror. A beam generator is connected to the scanner head via a fiber. The irradiation device 33 may be composed of a refraction type optical system such as a prism. The energy beam B is a high energy beam capable of performing welding. The energy beam B is, for example, a laser beam or an electron beam. The irradiation of the energy beam B is performed in an atmosphere of an inert gas.

Here, a method of setting the irradiation positions Pb1 and Pb2 will be described. The irradiation positions Pb1 and Pb2 are irradiation positions (positions of irradiation spots) of the energy beam B in the Y-axis direction. The reference center position Cr and the reference irradiation positions Pbr1 and Pbr2 are predetermined. The reference center position Cr is the center position of the tab laminate 21 which is a design reference. That is, the reference center position Cr is the center position of the tab laminated body 21 when the tab laminated body 21 is formed at the position as designed without causing a stacking deviation. The reference irradiation positions Pbr1 and Pbr2 are irradiation positions of the energy beam B in the Y-axis direction with respect to the reference center position Cr, and are irradiation positions of the energy beam B which is a design reference. That is, the reference irradiation positions Pbr1 and Pbr2 are the irradiation positions of the energy beam B when the tab laminate 21 is formed at the design position without causing the stacking deviation. The controller 34 calculates the distance D between the reference center position Cr and the center position Cp, and sets the irradiation positions Pb1 and Pb2 by shifting the reference irradiation positions Pbr1 and Pbr2 according to the distance D. More specifically, the controller 34 sets the irradiation positions Pb1 and Pb2 at positions shifted by the distance D from the reference irradiation positions Pbr1 and Pbr2 in the direction in which the center position Cp is deviated from the reference center position Cr. ..

The energy beam B is scanned along the X-axis direction on the side surface 21a of the tab stack 21. The energy beam B may be scanned along the X-axis direction while being displaced in the Z-axis direction. For example, the energy beam B is reciprocally displaced (wobbling) in the Z-axis direction and scanned along the X-axis direction. The amount of displacement of the irradiation spot of the energy beam B in the Z-axis direction is larger than the thickness of the tab laminate 21. The irradiation positions Pb1 and Pb2 of the energy beam B are located at the center of the side surface 21a of the tab laminate 21 in the Z-axis direction. For example, the energy beam B is scanned while moving the center point along the X-axis direction on the side surface 21a of the tab laminate 21 and rotating the irradiation spot of the energy beam B in the XZ plane around the center point. When the diameter of rotation is larger than the thickness of the tab laminate 21, the side surface 21a of the tab laminate 21, the conductive member 12, and the protective plate 23 are welded as a whole. That is, the welded portion 24 is formed over the side surface 21a of the tab laminate 21, the conductive member 12, and the protective plate 23.

As a result, the welded portion 24 is formed on the side surface 21a of the tab laminate 21 on which the protective plate 23 is placed in the Y-axis direction. When forming the welded portion 24, the tab laminate 21 may be pressed toward the conductive member 12 via the protective plate 23 by a jig (not shown). Similarly, when forming the welded portion 26, the tab laminate 22 may be pressed toward the conductive member 13 via the protective plate 25 by a jig (not shown).

By going through the above steps, the electrode assembly 3 is manufactured. After that, the electrode assembly 3 is housed in the main body 2a, and the tab laminates 21 and 22 are bent to connect the conductive member 12 and the positive electrode terminal 4, and also connect the conductive member 13 and the negative electrode terminal 5. Then, the power storage device 1 is manufactured by closing the opening of the main body 2a with the lid 2b.

Next, the action and effect of the manufacturing method M of the electrode assembly 3 will be described with reference to FIGS. 8A and 8B. FIG. 8 (a) is a diagram for explaining the irradiation position in the method for manufacturing the electrode assembly of the comparative example, and FIG. 8 (b) is a diagram for explaining the irradiation position in the method for manufacturing the electrode assembly shown in FIG. It is a figure for. Note that, in FIGS. 8A and 8B, only the configuration in which the tabs 14b of the plurality of positive electrodes 8 are welded to each other is shown, but the same applies to the configuration in which the tabs 16b of the plurality of negative electrodes 9 are welded to each other. ..

In the manufacturing method of the electrode assembly of the comparative example shown in FIG. 8A, the protective plate 23 is placed on the tab laminate 21 so that the center position Cb of the protective plate 23 is aligned with the reference center position Cr. NS. Then, the energy beam B is irradiated to the reference irradiation positions Pbr1 and Pbr2. In this case, the edge of the tab 14b is recessed inward with respect to the reference irradiation position Pbr1, and the edge of the tab 14b protrudes outward with respect to the reference irradiation position Pbr2. If the energy beam B is irradiated in such a state, welding may be defective.

On the other hand, as shown in FIG. 8B, in the manufacturing method M of the electrode assembly 3, the irradiation positions Pb1 and Pb2 of the energy beam B are determined according to the center position Cp of the tab laminate 21. Since the center position Cp of the tab laminate 21 is between the positions Pp1 and Pp2 of the ends 21d and 21e of the tab laminate 21, the tab 14b included in the tab laminate 21 is most displaced in the Y-axis direction. It is also an intermediate position between the edge of the tab 14b and the edge of the tab 14b that is most displaced to the other in the Y-axis direction. Therefore, by setting the irradiation positions Pb1 and Pb2 with reference to the center position Cp of the tab laminate 21, the amount of deviation of the edge of the tab 14b from the irradiation positions Pb1 and Pb2 can be reduced.

Specifically, the irradiation positions Pb1 and Pb2 are set at positions deviated from the reference irradiation positions Pbr1 and Pbr2 by the distance D in which the center position Cp of the tab laminate 21 is deviated from the reference center position Cr. As a result, the maximum amount of deviation of the edge of the tab 14b from the irradiation positions Pb1 and Pb2 can be equalized at the ends 21d and 21e of the tab laminate 21. Therefore, the amount of deviation of the edge of the tab 14b from the irradiation positions Pb1 and Pb2 can be reduced, and the welding accuracy of the tab laminate 21 can be improved.

Further, the protective plate 23 is placed on the tab laminated body 21 so that the central position Cb of the protective plate 23 is aligned with the central position Cp of the tab laminated body 21. Therefore, since the protective plate 23 is arranged so as not to overlap the irradiation positions Pb1 and Pb2, it is possible to prevent the energy beam B from being irradiated on the upper surface of the protective plate 23. Further, since the energy beam B is irradiated after the protective plate 23 is placed on the tab laminated body 21, it is possible to prevent the tab 14b of the tab laminated body 21 from being peeled off by the heat of the energy beam B.

When the tab width Wp of the tab laminate 21 is large, it means that the positional deviation (stacking deviation) between the plurality of tabs 14b included in the tab laminate 21 in the Y-axis direction is large. When the stacking deviation of the tab laminate 21 is large, even if the irradiation positions Pb1 and Pb2 are set with reference to the center position Cp of the tab laminate 21, the amount of deviation of the edge of the tab 14b from the irradiation positions Pb1 and Pb2 May not be small enough. In such a case, if the energy beam B is irradiated to the irradiation positions Pb1 and Pb2, welding failure may occur. Therefore, by forming the welded portion 24 on the side surface 21a of the tab laminated body 21 determined that the laminated state of the tab laminated body 21 is normal, it is possible to reduce the occurrence of welding defects.

According to the manufacturing method M of the electrode assembly 3, the tab laminated body 22 has the same effect as the tab laminated body 21.

Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment.

For example, in the manufacturing method M of the electrode assembly 3, steps S03 and S04 may be omitted. That is, steps S05 to S07 may be performed regardless of the laminated state of the tab laminated bodies 21 and 22.

Further, in the manufacturing method M of the electrode assembly 3, step S06 may be omitted. In this case, since the protective plate 23 is not provided on the tab laminate 21, the welded portion 24 is formed over the side surface 21a of the tab laminate 21 and the conductive member 12 in step S07. Similarly, since the protective plate 25 is not provided on the tab laminate 22, the welded portion 26 is formed over the side surface 22a of the tab laminate 22 and the conductive member 13 in step S07.

Further, in step S07, the welded portion 24 may be formed on at least one of the two side surfaces 21a. Similarly, the welded portion 26 may be formed on at least one of the two side surfaces 22a.

Further, in the above embodiment, the power storage device 1 is a lithium ion secondary battery, but the manufacturing method M is used in another secondary battery such as a nickel hydrogen battery, an electric double layer capacitor, or a power storage device such as a lithium ion capacitor. It can also be applied to the manufacture of electrode assemblies.

1 ... power storage device, 3 ... electrode assembly, 8 ... positive electrode, 9 ... negative electrode, 13 ... conductive member, 14b ... tab, 16b ... tab, 21 ... tab laminate, 21a ... side surface (end face), 21d, 21e ... end (Both ends), 22 ... Tab laminate, 22a ... Side surface (end face), 22d, 22e ... End (both ends), 23 ... Protective plate, 24 ... Welded part, 25 ... Protective plate, 26 ... Welded part, B ... Energy beam , Cb ... center position, Cp ... center position, Cr ... reference center position, D ... distance, M ... manufacturing method, Pb1, Pb2 ... irradiation position, Pbr1, Pbr2 ... reference irradiation position, Pp1, Pp2 ... position, Wp ... tab width.

Claims (3)

A method of manufacturing an electrode assembly, each having a plurality of electrodes including tabs.
A step of preparing a tab laminate in which the tabs of the plurality of electrodes are laminated in the first direction, and
A step of measuring the positions of both ends of the tab laminate in the second direction intersecting the first direction, and
A step of calculating the center position of the tab laminate in the second direction based on the positions of both ends, and
A step of forming a welded portion on the end face of the tab laminate in the second direction by irradiating the irradiation position in the second direction determined according to the center position with an energy beam for welding.
Equipped with a,
The reference center position, which is the design center position in the second direction of the tab laminate, and the reference irradiation position, which is the design irradiation position of the energy beam in the second direction, are predetermined.
The irradiation position, the reference center position and the Ru is set to a position shifted the reference irradiation position according to the distance between the center position of the tab laminate, the manufacturing method of the electrode assembly. A step of placing the protective plate on the tab laminate is further provided so that the center position of the protective plate in the second direction is aligned with the center position of the tab laminate.
The method for manufacturing an electrode assembly according to claim 1 , wherein in the forming step, the welded portion is formed over the protective plate and the end face. A step of calculating the length of the tab laminate along the second direction based on the positions of both ends, and
A step of confirming the laminated state of the tab laminated body based on the length, and
With more
The method for manufacturing an electrode assembly according to claim 1 or 2 , wherein in the forming step, the welded portion is formed on the end face of the tab laminated body determined to be in a normal laminated state.

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