Battery manufacturing method

Abstract

The present disclosure provides a method for manufacturing a battery that suppresses positional deviation of a plurality of electrode tabs after winding. A battery according to the method of manufacturing a battery according to the present invention is provided with: one or a plurality of wound electrode bodies in which a band-shaped first electrode plate and a band-shaped second electrode plate are stacked and wound via a band-shaped separator; and a battery case that accommodates the wound electrode bodies. The first electrode plate has a plurality of electrode tabs protruding from an end edge extending in the longitudinal direction, the plurality of electrode tabs including a first electrode tab (27) having a linear portion (27S) that is 90 DEG + / -5 DEG with respect to the end edge and has a length of 2 mm or more in a direction orthogonal to the end edge, and a second electrode tab (28) without a linear portion. The method for manufacturing a battery includes a step of detecting a linear portion of a first electrode tab, and cutting the first electrode plate at a position having a predetermined length from the linear portion with reference to the detected position of the first electrode tab in the longitudinal direction of the first electrode plate.

Description

[0001] This application is a divisional application of the invention patent application named "Battery", filed on November 9, 2021, and with application number 202111318011.0.

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS

[0003] This application claims priority based on Japanese Patent Application No. 2020-187462 filed on November 10, 2020, the entire contents of which are incorporated into this specification by reference. Technical Field

[0004] The present teaching relates to a method for manufacturing a battery. Background Art

[0005] In the past, it is known that there is a battery having a wound electrode body, wherein a strip-shaped positive electrode having a positive electrode active material layer on a positive electrode collector and a strip-shaped negative electrode having a negative electrode active material layer on a negative electrode collector are stacked via a strip-shaped separator and wound in the length direction. For example, as prior art, Japanese Patent No. 5127271, Japanese Patent No. 4449279, and Japanese Patent Application Publication No. 2009-129553 can be cited. For example, Japanese Patent No. 5127271 states the following: A plurality of electrode tabs in an isosceles trapezoidal shape are provided on the end edges extending in the length direction of a strip-shaped electrode plate (positive electrode plate and / or negative electrode plate), and after the plurality of electrode tabs are stacked by winding the electrode plate, they are electrically connected to the electrode terminal.

[0006] The electrode plate as described above is produced, for example, by the following manufacturing method, which includes the following steps: a step of intermittently cutting off the end edge of the current collector and forming a plurality of electrode tabs on the electrode plate, and a winding step of winding the electrode plate on a winding core and cutting it to a predetermined length (winding length). In the above-mentioned winding step, the cutting of the electrode plate can be performed, for example, using a cutting unit having a detection device and a cutting unit, wherein the detection device detects the position of the electrode tab provided on the electrode plate by laser, and the cutting unit cuts the electrode plate at a cutting position separated by a predetermined winding length based on the position of the electrode tab in the length direction detected by the detection device.

[0007] However, according to the research of the present inventors, "winding deviation" sometimes occurs during the winding process. Fig.18 Detailed description. Fig.18 It is a schematic top view of the winding process. Fig.18 The electrode plate 102 shown has a plurality of electrode tabs 102t in an isosceles trapezoidal shape. Fig.18In the figure, the second and subsequent electrode tabs 102t in the longitudinal direction W of the electrode plate 102 are omitted. The legs of the isosceles trapezoidal electrode tabs 102t (the sides in the height direction Y intersecting the longitudinal direction W) are inclined relative to the longitudinal direction W. Therefore, as shown in Fig.18 As shown by the imaginary line in FIG, when the electrode plate 102 moves in the height direction Y intersecting the length direction W during winding of the electrode plate 102 and the winding deviation occurs, the position of the electrode tab 102t detected by the laser changes. As a result, the position of the cutting of the electrode plate 102 is offset, and the cutting position at the cutting position (1) and the cutting position (2) are different. As a result, there is a problem that when a plurality of electrode tabs 102t are stacked by winding, the position of the electrode tab 102t deviates and the electrical connection with the electrode terminal (for example, welding connection with the collector sandwiched between the electrode tab and the electrode terminal) becomes difficult. Summary of the invention

[0008] The present disclosure has been made in view of the above circumstances, and an object of the present disclosure is to provide a method for manufacturing a battery in which the positional variations of a plurality of electrode tabs are suppressed after winding.

[0009] According to the teaching disclosed herein, a battery is provided, wherein the battery comprises: one or more wound electrode bodies, wherein the one or more wound electrode bodies are formed by stacking and winding a strip-shaped first electrode plate and a strip-shaped second electrode plate via a strip-shaped separator; and a battery case, wherein the battery case accommodates the wound electrode body. The first electrode plate has a plurality of electrode tabs protruding from an end edge extending in a length direction. The plurality of electrode tabs include: a first electrode tab, wherein the first electrode tab has a straight portion, wherein the straight portion is substantially perpendicular to the end edge, and the length in a direction orthogonal to the end edge is greater than 2 mm; and a second electrode tab, wherein the second electrode tab does not have the straight portion.

[0010] In the present disclosure, the electrode plate has a first electrode tab in addition to the second electrode tab, and the first electrode tab has a straight portion. Thus, even when the electrode plate moves in a direction intersecting the length direction during winding and a winding deviation occurs, the position of the electrode tab detected by the detection device is difficult to change. As a result, for example, compared with a solution having only an isosceles trapezoidal electrode tab, the electrode plate can be cut at a relatively accurate position. Therefore, after winding, the deviation of the positions of the plurality of tabs is suppressed.

[0011] In a preferred embodiment of the battery disclosed herein, the length of at least one of the second electrode tabs in the direction orthogonal to the length direction is greater than that of the first electrode tab, and the length of the root connected to the end edge in the length direction is greater than that of the first electrode tab. With such a structure, the strength of the second electrode tab can be improved. In addition, the conductive joint between the electrode terminal and the second electrode tab can be fully ensured. For example, the area for welding joint can be ensured to be larger on the second electrode tab. Thus, the resistance between the electrode terminal and the second electrode tab can be reduced. Moreover, when a plurality of electrode tabs are bent into bundles after winding, it is easy to align the positions of the ends of the electrode tabs. Thus, the accommodation to the battery case can be improved and the battery can be miniaturized.

[0012] In a preferred embodiment of the battery disclosed herein, the length of at least one of the second electrode tabs in the direction orthogonal to the length direction is smaller than that of the first electrode tab, and the length of the root connected to the end edge in the length direction is smaller than that of the first electrode tab. With such a structure, the strength of the first electrode tab can be improved. In addition, even if the first electrode tab has a straight portion, the conductive joint between the first electrode tab and the electrode terminal can be fully ensured. For example, the area for welding joint can be ensured to be larger on the first electrode tab. Thus, the resistance between the electrode terminal and the first electrode tab can be reduced. Moreover, when a plurality of electrode tabs are bent into bundles after winding, it is easy to align the positions of the ends of the electrode tabs. Thus, the accommodation to the battery case can be improved and the battery can be miniaturized.

[0013] In a preferred embodiment of the battery disclosed herein, the first electrode tab is arranged in an asymmetric shape in the length direction. With such a structure, the strength of the first electrode tab can be improved. In addition, even if the first electrode tab has a straight portion, the conductive joint between the first electrode tab and the electrode terminal can be fully ensured. For example, the area for welding joint can be ensured to be larger on the first electrode tab. Thus, the resistance between the electrode terminal and the first electrode tab can be reduced.

[0014] In a preferred embodiment of the battery disclosed herein, the first electrode tab has an inclined portion or a curved portion inclined relative to the straight portion between the base connected to the end edge and the straight portion in a direction orthogonal to the length direction. With such a structure, for example, when the first electrode tab is formed or the electrode plate is wound, stress is difficult to concentrate on the base, and it is difficult to break near the base. Therefore, the strength of the first electrode tab can be improved. In addition, even if vibration or impact is applied when the battery is in use, the electrical connection with the electrode terminal can be stably maintained, which can improve the conduction reliability of the battery.

[0015] In a preferred embodiment of the battery disclosed herein, the length of the first electrode tab from the base to the straight portion is 4 mm or more. With such a structure, for example, when the first electrode tab is formed or the electrode plate is wound, stress is difficult to concentrate on the base, and it is difficult to break near the base. Therefore, the strength of the first electrode tab can be improved. In addition, even if vibration or impact is applied when the battery is used, the electrical connection with the electrode terminal can be stably maintained, which can improve the conduction reliability of the battery.

[0016] In a preferred embodiment of the battery disclosed herein, when a straight line extending in the longitudinal direction through the end of one side of the straight portion in the direction in which the first electrode tab protrudes is set as a straight line La, and a straight line extending in the longitudinal direction through the end of the other side of the straight portion in the direction in which the first electrode tab protrudes is set as a straight line Lb, the first electrode tab has a region between the straight line La and the straight line Lb with a length of more than 10 mm in the longitudinal direction and a length of more than 3 mm in a direction orthogonal to the longitudinal direction. With such a structure, even if the first electrode tab has a straight portion, the conductive joint between the first electrode tab and the electrode terminal can be fully ensured. For example, the area for welding joint can be ensured to be larger on the first electrode tab. Thus, the resistance between the electrode terminal and the first electrode tab can be reduced.

[0017] In a preferred embodiment of the battery disclosed herein, the battery case includes: an outer body, the outer body having a bottom wall, a pair of first side walls extending from the bottom wall and facing each other, a pair of second side walls extending from the bottom wall and facing each other, and an opening facing the bottom wall; and a sealing plate, the sealing plate seals the opening of the outer body, and the battery also has: an electrode terminal, the electrode terminal is fixed to the sealing plate; and a collector, the collector electrically connects the electrode terminal to the first electrode tab. A plurality of electrode tabs are stacked at the end of the wound electrode body in the direction along the first side wall, and the collector has a tab connection surface connected to the first electrode tab at the end in the direction along the first side wall. With such a structure, the electrical connection with the electrode terminal can be stably maintained, and the conduction reliability of the battery can be improved.

[0018] In a preferred embodiment of the battery disclosed herein, the wound electrode bodies are plural. According to the present disclosure, since the plural wound electrode bodies can be charged and discharged with good balance, excellent cycle characteristics can be achieved even when the plural wound electrode bodies are provided.

[0019] In a preferred embodiment of the battery disclosed herein, the number of the electrode tabs is greater than 0.8 relative to the number of layers of the first electrode plate. With such a structure, the internal resistance can be reduced to a high level, and the output characteristics of the battery can be improved.

[0020] In addition, according to the teaching disclosed herein, a method for manufacturing a battery is provided, wherein the battery comprises: one or more wound electrode bodies, wherein the one or more wound electrode bodies are formed by stacking and winding a strip-shaped first electrode plate and a strip-shaped second electrode plate via a strip-shaped separator; and a battery case, wherein the battery case accommodates the wound electrode bodies, wherein the first electrode plate has a plurality of electrode tabs protruding from an end edge extending in a length direction, and the plurality of electrode tabs include: a first electrode tab, wherein the first electrode tab has a straight portion, wherein the straight portion is 90°±5° relative to the end edge, and the length in a direction orthogonal to the end edge is greater than 2 mm; and a second electrode tab, wherein the second electrode tab does not have the straight portion, and the method for manufacturing the battery includes the following steps: detecting the straight portion of the first electrode tab, and cutting the first electrode plate at a position of a predetermined length away from the straight portion based on the detected position of the first electrode tab in the length direction of the first electrode plate. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a perspective view schematically showing a battery according to one embodiment.

[0022] Figure 2 It is along Figure 1 Schematic longitudinal cross-sectional view along line II-II.

[0023] Figure 3 It is along Figure 1 Schematic longitudinal cross-sectional view along line III-III.

[0024] Figure 4 It is along Figure 1 Schematic cross-sectional view of line IV-IV.

[0025] Figure 5 It is a perspective view schematically showing the electrode assembly mounted on the sealing plate.

[0026] Figure 6 It is a perspective view schematically showing an electrode body to which a positive electrode second current collecting portion and a negative electrode second current collecting portion are attached.

[0027] Figure 7 is a schematic diagram showing the structure of a wound electrode body.

[0028] Figure 8 This is a schematic top view of a positive electrode according to one embodiment.

[0029] Fig. 9 Is winding Figure 8 Schematic partial side view of the positive electrode.

[0030] Fig.10 It is schematically shown Figure 2 A partial enlarged cross-sectional view of the vicinity of the positive terminal.

[0031] Fig.11 It is a perspective view schematically showing a sealing plate to which a positive electrode terminal, a negative electrode terminal, a positive electrode first current collecting portion, a negative electrode first current collecting portion, a positive electrode insulating member, and a negative electrode insulating member are attached.

[0032] Fig.12 Yes Fig.11 A three-dimensional image of the sealing plate after it is turned over.

[0033] Fig.13 This is a schematic top view of a winding step according to one embodiment.

[0034] Fig.14 This is a schematic cross-sectional view for explaining a battery insertion step according to one embodiment.

[0035] Fig.15A , Fig. 15B , Fig. 15C and Fig.15D Each of them is a schematic plan view showing a detection tab according to a modified example.

[0036] Fig.16A is a schematic top view of a positive electrode having a common tab of a first variant, Fig. 16B The positive electrode of the first modification example is Fig. 9 The corresponding figure.

[0037] Fig.17A is a schematic top view of a positive electrode having a common electrode tab of a second modified example, Fig. 17B The positive electrode of the second modification example is Fig. 9 The corresponding figure.

[0038] Fig.18 It is a schematic top view of the winding process of the prior art.

[0039] Description of Reference Numerals

[0040] 12 outer body

[0041] 14 Sealing plate

[0042] 20 Electrode assembly

[0043] 20a, 20b, 20c wound electrode body

[0044] 20f Flat part

[0045] 20r Bend

[0046] 22t positive electrode tab

[0047] 23. Positive electrode tab set

[0048] 27 Detection tab

[0049] 27S Straight Line

[0050] 28a, 28b, 28c, 28d, 28e ordinary tabs

[0051] 100 Batteries. DETAILED DESCRIPTION

[0052] Hereinafter, some preferred embodiments of the technology disclosed herein are described with reference to the accompanying drawings. In addition, matters required for the implementation of the technology disclosed herein (such as the general structure and manufacturing process of the battery that do not give characteristics to the technology disclosed herein) other than the matters specifically mentioned in this specification can be grasped as design matters for those skilled in the art based on the prior art in this field. The technology disclosed herein can be implemented based on the contents disclosed in this specification and the technical common sense in this field. In addition, in this specification, the expression "A to B" showing the range not only includes the meaning of above A and below B, but also includes the meaning of "preferably greater than A" and "preferably less than B".

[0053] In addition, in this specification, "battery" refers to a term for all power storage devices that can extract electric energy, and is a concept that includes primary batteries and secondary batteries. In addition, in this specification, "secondary battery" refers to a term for all power storage devices that can be repeatedly charged and discharged, and is a concept that includes so-called storage batteries (chemical batteries) such as lithium-ion secondary batteries and nickel-metal hydride batteries, and capacitors (physical batteries) such as double-layer capacitors.

[0054] <Battery 100>

[0055] Figure 1 It is a perspective view of the battery 100 . Figure 2 It is along Figure 1 Schematic longitudinal cross-sectional view along line II-II. Figure 3 It is along Figure 1 Schematic longitudinal cross-sectional view along line III-III. Figure 4 It is along Figure 1 Schematic cross-sectional view of line IV-IV of the battery 100. In the following description, the reference numerals L, R, F, Rr, U, and D in the drawings represent left, right, front, rear, top, and bottom, and the reference numerals X, Y, and Z in the drawings represent the short side direction, the long side direction orthogonal to the short side direction, and the up and down direction of the battery 100, respectively. However, these are only directions for convenience of description and do not limit the arrangement of the battery 100 in any way.

[0056] like Figure 2 As shown, the battery 100 includes a battery case 10, an electrode assembly 20, a positive electrode terminal 30, a negative electrode terminal 40, a positive electrode collector 50, a negative electrode collector 60, a positive electrode insulating member 70, and a negative electrode insulating member 80. Although not shown in the figure, the battery 100 also includes an electrolyte. The battery 100 is a lithium ion secondary battery.

[0057] The battery case 10 is a frame that contains the electrode assembly 20. Here, the battery case 10 has a flat rectangular parallelepiped (square) shape with a bottom. The material of the battery case 10 can be the same as that used in the past, and there is no particular restriction. The battery case 10 is preferably made of metal, for example, more preferably made of aluminum, aluminum alloy, iron, iron alloy, etc. Figure 2 As shown, the battery case 10 includes an exterior body 12 having an opening 12 h and a sealing plate (lid body) 14 that closes the opening 12 h.

[0058] like Figure 1 As shown, the outer body 12 includes a bottom wall 12a, a pair of long side walls 12b extending from the bottom wall 12a and facing each other, and a pair of short side walls 12c extending from the bottom wall 12a and facing each other. The bottom wall 12a is roughly rectangular. The bottom wall 12a faces the opening 12h. The area of ​​the short side wall 12c is smaller than the area of ​​the long side wall 12b. The long side wall 12b and the short side wall 12c are examples of the first side wall and the second side wall.

[0059] The sealing plate 14 is mounted on the outer body 12 in a manner that blocks the opening 12h of the outer body 12. The sealing plate 14 faces the bottom wall 12a of the outer body 12. The sealing plate 14 is substantially rectangular when viewed from above. The battery case 10 is integrated by joining the sealing plate 14 to the periphery of the opening 12h of the outer body 12 (for example, by welding). The battery case 10 is hermetically sealed (sealed).

[0060] like Figure 2 As shown, the sealing plate 14 is provided with a liquid injection hole 15, a gas discharge valve 17 and two terminal lead holes 18, 19. The liquid injection hole 15 is used to inject the electrolyte after the sealing plate 14 is assembled to the outer body 12. The liquid injection hole 15 is sealed by a sealing member 16. The gas discharge valve 17 is configured to break when the pressure in the battery case 10 becomes above a specified value, and discharge the gas in the battery case 10 to the outside. The terminal lead holes 18, 19 are respectively formed at both ends of the long side direction Y of the sealing plate 14. The terminal lead holes 18, 19 penetrate the sealing plate 14 in the up and down direction Z. The terminal lead holes 18, 19 each have an inner diameter of a size that can be inserted through the positive terminal 30 and the negative terminal 40 installed before the sealing plate 14 (before riveting).

[0061] The positive electrode terminal 30 and the negative electrode terminal 40 are respectively fixed to the sealing plate 14. The positive electrode terminal 30 is arranged on one side of the sealing plate 14 in the longitudinal direction Y ( Figure 1 , Figure 2 The negative terminal 40 is arranged on the other side of the sealing plate 14 in the longitudinal direction Y ( Figure 1 , Figure 2 on the right side of the Figure 1 As shown in FIG. 1 , the positive electrode terminal 30 and the negative electrode terminal 40 are exposed on the outer surface of the sealing plate 14. Figure 2 As shown, the positive terminal 30 and the negative terminal 40 are inserted through the terminal lead-out holes 18 and 19 and extend from the inside of the sealing plate 14 to the outside. The positive terminal 30 and the negative terminal 40 are riveted to the peripheral edge of the terminal lead-out holes 18 and 19 surrounding the sealing plate 14 by riveting. Figure 2 The positive terminal 30 and the negative terminal 40 are examples of electrode terminals.

[0062] like Figure 2 As shown, the positive electrode terminal 30 is connected to the positive electrode 22 (see FIG. Figure 7 The positive electrode terminal 30 is electrically connected to the sealing plate 14 by the positive electrode insulating member 70 and the gasket 90. The positive electrode terminal 30 is preferably made of metal, and more preferably made of aluminum or an aluminum alloy.

[0063] The negative electrode terminal 40 is connected to the negative electrode 24 (see Figure 7 ) is electrically connected. The negative terminal 40 is insulated from the sealing plate 14 by a negative electrode insulating member 80 and a gasket 90. The negative terminal 40 is preferably made of metal, for example, more preferably made of copper or a copper alloy. The two conductive members can be joined and integrated to form the negative terminal 40. For example, the portion connected to the negative electrode collector 60 may be made of copper or a copper alloy, and the portion exposed on the surface of the outer side of the sealing plate 14 may be made of aluminum or an aluminum alloy.

[0064] like Figure 1As shown, a plate-shaped positive electrode external conductive member 32 and a negative electrode external conductive member 42 are installed on the outer surface of the sealing plate 14. The positive electrode external conductive member 32 is electrically connected to the positive terminal 30. The negative electrode external conductive member 42 is electrically connected to the negative terminal 40. The positive electrode external conductive member 32 and the negative electrode external conductive member 42 are components to which bus bars are attached when a plurality of batteries 100 are electrically connected to each other. The positive electrode external conductive member 32 and the negative electrode external conductive member 42 are preferably made of metal, for example, more preferably made of aluminum or an aluminum alloy. The positive electrode external conductive member 32 and the negative electrode external conductive member 42 are insulated from the sealing plate 14 by an external insulating member 92. However, the positive electrode external conductive member 32 and the negative electrode external conductive member 42 are not required and can be omitted in other embodiments.

[0065] Figure 5 1 is a perspective view schematically showing an electrode assembly 20 mounted on a sealing plate 14. Here, the electrode assembly 20 has three wound electrode bodies 20a, 20b, and 20c. According to the technology disclosed herein, since a plurality of wound electrode bodies 20a, 20b, and 20c can be charged and discharged in a well-balanced manner, excellent cycle characteristics can be achieved. However, the number of wound electrode bodies arranged inside an outer casing 12 is not particularly limited, and may be two or more (plural) or one. Here, the electrode assembly 20 is held by an electrode assembly retainer 29 (see Figure 3 ) is arranged inside the outer casing 12 in a covered state, and the electrode body holder 29 is composed of a resin sheet.

[0066] Figure 6 It is a perspective view schematically showing the wound electrode body 20 a. Figure 7 Schematic diagram showing the structure of the wound electrode body 20a. In addition, the wound electrode body 20a is described in detail below as an example, and the wound electrode bodies 20b and 20c can also be made into the same structure.

[0067] The wound electrode body 20a includes a positive electrode 22, a negative electrode 24, and a separator 26. Here, the strip-shaped positive electrode 22 and the strip-shaped negative electrode 24 are stacked via two strip-shaped separators 26 and wound around a winding axis WL to form the wound electrode body 20a. The wound electrode body 20a has a flat shape. The wound electrode body 20a is arranged inside the outer casing 12 in a direction in which the winding axis WL is substantially parallel to the longitudinal direction Y. Figure 3 As shown, the wound electrode body 20a has a pair of curved portions (R portions) 20r facing the bottom wall 12a of the outer casing 12 and the sealing plate 14, and a flat portion 20f connecting the pair of curved portions 20r and facing the long side wall 12b of the outer casing 12. The flat portion 20f extends along the long side wall 12b.

[0068] like Figure 7As shown, the positive electrode 22 has a positive electrode collector 22c, a positive electrode active material layer 22a fixed to the surface of at least one side of the positive electrode collector 22c, and a positive electrode protective layer 22p. However, the positive electrode protective layer 22p is not necessary and can be omitted in other embodiments. The positive electrode collector 22c is in a strip shape. The positive electrode collector 22c is composed of a conductive metal such as aluminum, aluminum alloy, nickel, stainless steel, etc. The positive electrode collector 22c is a metal foil, specifically aluminum foil. The positive electrode 22 is an example of a first electrode plate or a second electrode plate.

[0069] At one end portion of the positive electrode current collector 22c in the longitudinal direction Y ( Figure 7 A plurality of positive electrode tabs 22t are provided at the left end of the plurality of positive electrode tabs 22t. Figure 7 The plurality of positive electrode tabs 22t protrude in the longitudinal direction Y relative to the separator 26. The plurality of positive electrode tabs 22t are arranged at intervals (intermittently) along the longitudinal direction of the positive electrode 22. However, the positive electrode tab 22t may also be arranged at the other end ( Figure 7 The positive electrode tab 22t is a part of the positive electrode collector 22c and is made of metal foil (aluminum foil). A positive electrode protective layer 22p is formed on a part of the positive electrode tab 22t, specifically, in an area of ​​the detection tab 27 described later that is closer to the base than the straight line Lb and in an area of ​​the ordinary tabs 28a to 28e that is closer to the base. In at least a part of the positive electrode tab 22t, the positive electrode active material layer 22a and the positive electrode protective layer 22p are not formed, and the positive electrode collector 22c is exposed. The positive electrode tab 22t is an example of an electrode tab.

[0070] like Figure 4 As shown, the plurality of positive electrode tabs 22t are provided at one end portion in the longitudinal direction Y ( Figure 4 The positive electrode tab group 23 is stacked with the positive electrode tab 22t at the left end thereof and constitutes a positive electrode tab group 23. The plurality of positive electrode tabs 22t are bent and curved in such a way that the ends on the outer sides are aligned. Thus, the accommodation to the battery case 10 can be improved and the battery 100 can be miniaturized. The positive electrode tab group 23 is electrically connected to the positive terminal 30 via the positive electrode collector 50. Preferably, the plurality of positive electrode tabs 22t are bent and electrically connected to the positive terminal 30. A positive second collector 52 described later is attached to the positive electrode tab group 23.

[0071] like Figure 7As shown, the positive electrode active material layer 22a is arranged in a strip shape along the length direction of the strip-shaped positive electrode collector 22c. The positive electrode active material layer 22a contains a positive electrode active material (such as a lithium transition metal composite oxide such as a lithium nickel cobalt manganese composite oxide) that can reversibly absorb and release charge carriers. When the solid content of the positive electrode active material layer 22a is set to 100% by mass as a whole, the positive electrode active material can account for approximately 80% by mass or more, typically more than 90% by mass, for example, more than 95% by mass. The positive electrode active material layer 22a may include any component other than the positive electrode active material, such as a conductive material, a binder, various added components, etc. As a conductive material, for example, a carbon material such as acetylene black (AB) can be used. As a binder, for example, polyvinylidene fluoride (PVdF) can be used.

[0072] like Figure 7 As shown, the positive electrode protection layer 22p is provided at the boundary portion between the positive electrode current collector 22c and the positive electrode active material layer 22a in the longitudinal direction Y. Here, the positive electrode protection layer 22p is provided at one end portion of the positive electrode current collector 22c in the longitudinal direction Y ( Figure 7 The positive electrode protective layer 22p is provided at both ends in the long side direction Y. The positive electrode protective layer 22p is provided in a strip shape along the positive electrode active material layer 22a. The positive electrode protective layer 22p contains an inorganic filler (e.g., aluminum oxide). When the solid content of the positive electrode protective layer 22p as a whole is set to 100% by mass, the inorganic filler may account for approximately 50% by mass or more, typically 70% by mass or more, for example, 80% by mass or more. The positive electrode protective layer 22p may contain any component other than the inorganic filler, such as a conductive material, a binder, various additives, and the like. The conductive material and the binder may be the same as the substances that may be included in the positive electrode active material layer 22a and are exemplified.

[0073] Figure 8 2 is a schematic top view of the positive electrode 22. In the following description, Figure 8 The reference numerals W and Y in the figure respectively represent the length direction of the positive electrode 22 and the height direction orthogonal to the length direction of the positive electrode 22. In addition, the length direction W is a direction consistent with the winding direction of the wound electrode body 20a. The reference numerals W1 and W2 represent the starting side and the terminal side of the winding direction. The height direction Y is the direction in which the detection tab 27 protrudes, and is a direction consistent with the long side direction Y of the battery 100. The reference numeral B indicates the bending position of the bend in order to form the bent portion 20r in the winding process described later. In addition, below, the positive electrode 22 is described in detail as an example, and the negative electrode 24 (specifically, the negative electrode tab 24t described later) can also be set to the same structure.

[0074] like Figure 8As shown, the positive electrode 22 has an end 22e extending along the length direction W. A plurality of positive electrode tabs 22t extend from the end 22e of the positive electrode 22 to one side in the height direction Y ( Figure 8 The plurality of positive electrode tabs 22t include: a detection tab 27 having a prescribed straight portion 27S and a plurality of ordinary tabs 28a to 28e without a prescribed straight portion 27S. The detection tab 27 is one here. However, there may be two or more (plural) detection tabs 27. The ordinary tabs 28a to 28e are multiple here. However, there may also be one detection tab 27. The detection tab 27 is an example of a first electrode tab having a straight portion 27S, and the ordinary tabs 28a to 28e are an example of a second electrode tab without a straight portion 27S.

[0075] Here, a plurality of positive electrode tabs 22t are arranged one by one in the area divided by the bending position B. That is, the number of positive electrode tabs 22t is the same as the number of layers of the positive electrode 22 (one tab / layer). When one turn of the positive electrode 22 is wound on the winding axis WL in the winding process, the positive electrode tab 22t is stacked twice on the front and rear sides as viewed from the winding axis WL. Therefore, the number of positive electrode tabs 22t is 2 tabs / number of windings (turns). The number of positive electrode tabs 22t is preferably approximately 0.5 (0.5 tabs / layer) or more relative to the number of layers of the positive electrode 22, and more preferably 0.8 (0.8 tabs / layer) or more. With such a structure, the internal resistance can be reduced at a higher level, and the output characteristics of the battery can be improved.

[0076] The detection tab 27 is a portion that is read by a detection device (such as a laser detection device) when the strip-shaped positive electrode 22 is cut into a predetermined winding length in the winding process described later and serves as a reference for determining the cutting position. Figure 8 As shown, in the longitudinal direction W of the positive electrode 22, the detection tab 27 is arranged at the beginning (the most beginning side W1) of the predetermined winding length. The detection tab 27 is preferably arranged at a position closest to the winding axis WL of the wound electrode body 20a among the plurality of positive electrode tabs 22t. As a result, the positional deviation from the second positive electrode tab 22t (here, the normal tab 28a) to the tail end of the winding length predetermined in the longitudinal direction W can be suppressed to a small tolerance of, for example, about ±0.5 mm.

[0077] In the predetermined winding length, the detection tab 27 is preferably arranged at the beginning (most starting end side W1) and / or the end (final end side W2). In other words, the detection tab 27 is preferably arranged at a position closest to the cutting position of the positive electrode 22. By bringing the detection tab 27 close to the cutting position, the positive electrode 22 can be cut with high precision at an accurate position. In addition, for example, even if the speed of winding the positive electrode 22 increases from the beginning of winding to the middle of the winding process, the influence on the winding speed can be avoided.

[0078] The detection tab 27 extends from the base connected to the end 22e of the positive electrode 22. The shape of the detection tab 27 is not particularly limited as long as it has a straight portion 27S. The detection tab 27 can be a polygon such as a pentagon, a quadrilateral, or a triangle. The shape of the detection tab 27 is a pentagon here. As a result, when forming the detection tab 27, etc. (for example, when removing the scraps generated when processing the positive electrode collector 22c), stress is difficult to concentrate on the base of the detection tab 27, and it is difficult to break near the base. In addition, during the winding process, it is difficult for the tab of the detection tab 27 to break. In addition, it is difficult for the current to concentrate on the base of the detection tab 27, which can suppress the heat concentration near the base or the increase in resistance near the base during the charging and discharging of the battery 100.

[0079] Here, the detection tab 27 is provided in an asymmetric shape in the length direction W. Thus, the strength of the detection tab 27 can be improved. In addition, a larger area can be ensured on the detection tab 27 for welding and joining with the positive electrode second current collecting portion 52 described later, and the resistance between the detection tab 27 and the positive electrode terminal 30 can be reduced. The length (tab height) Tt of the detection tab 27 in the height direction Y is approximately 13 to 22 mm, for example, 17.5 mm.

[0080] The straight portion 27S is arranged substantially perpendicular to the end 22e of the positive electrode 22 (90°±5°). The angle of the straight portion 27S to the end 22e is preferably 90°±2°. In addition, when the detection tab 27 does not have the straight portion 27S, for example Fig.18 The angle of the legs of the isosceles trapezoidal shape relative to the end side can be about 80°±2°. The length of the straight portion 27S in the direction perpendicular to the end side 22e (here the same as the length in the height direction Y) is more than 2 mm. Thus, for example, even if the tolerance of the size when processing the positive electrode collector 22c and forming the detection tab 27 is about ±0.5 mm, the effect of the technology disclosed herein can be appropriately achieved. The length of the straight portion 27S is preferably 3 to 20 mm, and more preferably 5 to 15 mm (10±5 mm). Thus, for example, the tolerance of the winding offset can be suppressed to about ±1.0 mm.

[0081] The detection tab 27 preferably has an inclined portion or a curved portion that is inclined relative to the straight portion 27S between the base connected to the end 22e of the positive electrode 22 and the straight portion 27S in the height direction Y. Here, the detection tab 27 has an inclined portion 27a between the base and the straight portion 27S. With such a structure, for example, when the detection tab 27 is formed or when the positive electrode 22 is wound, the base of the detection tab 27 is difficult to break, and the strength of the detection tab 27 can be improved. In addition, even if vibration or impact is applied when the battery 100 is used, the electrical connection with the positive terminal 30 can be stably maintained, which can improve the conduction reliability of the battery 100.

[0082] In the height direction Y, the length (height) Ts from the base to the straight portion 27S is preferably 4 mm or more. Thus, the above-mentioned effect can be exerted at a higher level. The height Ts from the base to the straight portion 27S is shorter than the tab height Tt of the detection tab 27. The height Ts from the base to the straight portion 27S is preferably 10% or more of the tab height Tt, more preferably 15% or more, and further preferably 20% or more. Thus, it is difficult for the tab to break during the winding process. In addition, it is difficult for the current to concentrate on the base, and it is possible to suppress the heat concentration near the base or the increase in resistance near the base during the charging and discharging of the battery 100. The height Ts from the base to the straight portion 27S can be approximately 50% or less of the tab height Tt, for example, less than 30%. The height Ts from the base to the straight portion 27S can also be longer than the length of the straight portion 27S.

[0083] like Figure 8 As shown, at one end portion ( Figure 8 The upper end of the straight portion 27S, which is the same as the upper end of the detection tab 27, is defined as a straight line La extending in the length direction W, and the other end portion ( Figure 8 When a straight line extending in the length direction W (i.e., the lower end of the detection electrode tab 27) is set as a straight line Lb, the detection electrode tab 27 has an area Wa between the above-mentioned straight line La and the above-mentioned straight line Lb. The area Wa is a portion for welding the detection electrode tab 27 to the positive electrode second collector 52 described later. The area Wa may be an area with a length of more than 10 mm in the length direction W and a length of more than 3 mm in the height direction Y. With such a structure, even when the detection electrode tab 27 has a straight portion 27S, the conductive joint between the detection electrode tab 27 and the positive terminal 30 can be fully ensured, and the resistance can be reduced.

[0084] The ordinary pole tabs 28a to 28e constitute the positive pole tabs 22t in the longitudinal direction W of the positive electrode 22, for example, from the second to the last in the prescribed winding length. The ordinary pole tabs 28a to 28e constitute the positive pole tabs 22t other than the detection pole tabs 27. The shape of the ordinary pole tabs 28a to 28e is not particularly limited as long as there is no straight line portion 27S. The ordinary pole tabs 28a to 28e can be polygonal shapes such as quadrilaterals and triangles, or semicircular shapes. The shape of the ordinary pole tabs 28a to 28e can be, for example, a trapezoid such as an isosceles trapezoid, a rectangle, a square, etc. It is also possible that the ordinary pole tabs 28a to 28e are set in a shape symmetrical in the longitudinal direction W.

[0085] The shape of the ordinary tabs 28a to 28e is preferably a trapezoid. As a result, when forming the detection tab 27, etc., stress is less likely to be concentrated on the base, and the base vicinity is less likely to break. In addition, the tab is less likely to break during the winding process. In addition, the current is less likely to be concentrated on the base, which can prevent heat from being concentrated near the base or resistance from increasing near the base during charging and discharging of the battery 100.

[0086] The dimensions of the plurality of common tabs 28a to 28e (eg, the tab length in the length direction W and / or the length in the height direction Y (tab height)) may be the same or different from each other. Figure 8 As shown, here, the sizes of the plurality of common tabs 28a to 28e are different from each other.

[0087] In some embodiments, it is preferred that the height of at least one of the plurality of common tabs 28a to 28e is smaller than that of the detection tab 27, and the length W of the base in the longitudinal direction (the width of the base) is smaller than that of the detection tab 27. Thus, the strength of the detection tab 27 can be improved. In addition, the area Wa for welding and joining can be ensured to be larger on the detection tab 27, and the resistance between the positive terminal 30 and the detection tab 27 can be reduced. In addition, when the plurality of positive tabs 22t are bundled and bent after winding, the positions of the ends are easily aligned.

[0088] In addition, in some embodiments, it is preferred that the height of at least one of the plurality of common tabs 28a to 28e is greater than the detection tab 27, and the length W of the base in the longitudinal direction (the width of the base) is greater than the detection tab 27. Thus, the strength of at least one common tab 28a to 28e can be improved. In addition, the area Wa for welding and joining can be ensured to be larger on at least one common tab 28a to 28e, and the resistance of the positive terminal 30 and the detection tab 27 can be reduced. In addition, when the plurality of positive tabs 22t are bent into a bundle after winding, it is easy to align the positions of the ends.

[0089] like Figure 8As shown, in the length direction W (in other words, the winding direction), the height Ta of the common pole lug 28a located at the beginning among the plurality of common pole lugs 28a to 28e becomes the average of the lug heights of the plurality of common pole lugs 28a to 28e. The height Tb of the common pole lug 28b located at the second position is smaller than the lug height Ta of the common pole lug 28a. The height Td of the common pole lug 28d located at the fourth position is smaller than the lug height Tb of the common pole lug 28b. The lug heights Tb and Td of the even-numbered common pole lugs 28b and 28d located in the length direction W among the plurality of common pole lugs 28a to 28e gradually decrease from the starting end side W1 toward the terminal side W2. On the other hand, the height Tc of the common pole lug 28c located at the third position is larger than the lug height Ta of the common pole lug 28a. The height Te of the common pole lug 28e located at the fifth position is larger than the lug height Tc of the common pole lug 28c. Among the plurality of normal tabs 28 a to 28 e , the normal tabs 28 c and 28 e located at odd numbers in the longitudinal direction W have tab heights Tc and Te that gradually increase from the starting end side W1 toward the ending end side W2 .

[0090] Fig. 9 Is winding Figure 8 A schematic partial side view of the positive electrode 22. In addition, Fig. 9 In the figure, the detection tab 27 is omitted. Fig. 9 As shown in FIG. 1 , when the positive electrode 22 is bent at the bending position B and wound, the length of the common tabs 28a to 28e in the long side direction Y gradually increases from one side in the short side direction X to the other side. Figure 4 As shown, when the plurality of normal tabs 28a to 28e are bent, the outer end portions can be appropriately aligned.

[0091] like Figure 7 As shown, the negative electrode 24 has a negative electrode collector 24c and a negative electrode active material layer 24a fixed to at least one surface of the negative electrode collector 24c. The negative electrode collector 24c is in a strip shape. The negative electrode collector 24c is made of, for example, a conductive metal such as copper, a copper alloy, nickel, or stainless steel. The negative electrode collector 24c is a metal foil, specifically a copper foil. The negative electrode 24 is an example of a first electrode plate or a second electrode plate.

[0092] At one end portion of the negative electrode current collector 24c in the longitudinal direction Y ( Figure 7 A plurality of negative electrode tabs 24t are provided at the right end of the negative electrode 24. The plurality of negative electrode tabs 24t protrude in the longitudinal direction Y compared to the separator 26. The plurality of negative electrode tabs 24t are provided at intervals (intermittently) along the longitudinal direction of the negative electrode 24. The negative electrode tab 24t extends to one side ( Figure 7 However, the negative electrode tab 24t may also be provided at the other end portion in the longitudinal direction Y ( Figure 7The negative electrode tab 24t is a part of the negative electrode collector 24c and is made of metal foil (copper foil). A negative electrode active material layer 24a is formed on a part of the negative electrode tab 24t. The negative electrode active material layer 24a is not formed on at least a part of the negative electrode tab 24t, and the negative electrode collector 24c is exposed. The negative electrode tab 24t is an example of an electrode tab.

[0093] like Figure 4 As shown, the negative electrode tabs 24t are provided at one end portion in the longitudinal direction Y ( Figure 6 The negative electrode tab group 25 is stacked with the positive electrode tab group 23 (right end portion) to form a negative electrode tab group 25. The negative electrode tab group 25 is arranged at a position symmetrical to the positive electrode tab group 23 in the long side direction Y. The multiple negative electrode tabs 24t are bent and curved in a manner that the ends on the outer side are aligned. As a result, it is possible to improve the accommodation to the battery case 10 and to miniaturize the battery 100. The negative electrode tab group 25 is electrically connected to the negative terminal 40 via the negative electrode collector 60. It is preferred that the multiple negative electrode tabs 24t are bent and electrically connected to the negative terminal 40. A negative electrode second collector 62 described later is attached to the negative electrode tab group 25. The multiple negative electrode tabs 24t here are different in size from each other in a manner that the ends on the outer side are aligned when they are bent, similarly to the multiple positive electrode tabs 22t.

[0094] like Figure 7 As shown, the negative electrode active material layer 24a is arranged in a strip shape along the length direction of the strip-shaped negative electrode collector 24c. The negative electrode active material layer 24a contains a negative electrode active material (such as a carbon material such as graphite) that can reversibly absorb and release charge carriers. When the solid content of the negative electrode active material layer 24a is set to 100% by mass as a whole, the negative electrode active material can account for approximately 80% by mass or more, typically more than 90% by mass, for example, more than 95% by mass. The negative electrode active material layer 24a may contain any component other than the negative electrode active material, such as a binder, a dispersant, various additives, and the like. As a binder, for example, rubbers such as styrene butadiene rubber (SBR) can be used. As a dispersant, for example, celluloses such as carboxymethyl cellulose (CMC) can be used.

[0095] The separator 26 is a member that insulates the positive electrode active material layer 22a of the positive electrode 22 from the negative electrode active material layer 24a of the negative electrode 24. Here, the separator 26 constitutes the outer surface of the wound electrode body 20a. As the separator 26, for example, a porous sheet made of a resin composed of a polyolefin resin such as polyethylene (PE) and polypropylene (PP) is suitable. Preferably, the separator 26 has a substrate portion composed of a porous sheet made of a resin and a heat-resistant layer (Heat Resistance Layer: HRL) formed on the surface of at least one side of the substrate portion. The heat-resistant layer is a layer containing an inorganic filler. As an inorganic filler, for example, alumina, boehmite, aluminum hydroxide, titanium dioxide, etc. can be used.

[0096] The electrolyte can be the same as before and is not particularly limited. The electrolyte is, for example, a non-aqueous electrolyte containing a non-aqueous solvent and a supporting salt. The non-aqueous solvent includes, for example, carbonates such as ethylene carbonate, dimethyl carbonate, and ethyl methyl carbonate. The supporting salt is, for example, a fluorine-containing lithium salt such as LiPF6. However, the electrolyte can also be solid (solid electrolyte) and integrated with the electrode assembly 20.

[0097] The positive electrode current collecting portion 50 constitutes a conduction path that electrically connects the positive electrode tab group 23 and the positive electrode terminal 30, wherein the positive electrode tab group 23 is composed of a plurality of positive electrode tabs 22t. Figure 2 As shown, the positive electrode current collecting portion 50 includes a positive electrode first current collecting portion 51 and a positive electrode second current collecting portion 52. The positive electrode first current collecting portion 51 and the positive electrode second current collecting portion 52 can be made of the same metal type as the positive electrode current collector 22c, for example, conductive metal such as aluminum, aluminum alloy, nickel, stainless steel, etc. The positive electrode current collecting portion 50 is an example of a current collecting portion.

[0098] Fig.10 It is schematically shown Figure 2 A partial enlarged cross-sectional view of the vicinity of the positive electrode terminal 30 . Fig.11 It is a perspective view schematically showing the sealing plate 14 . Fig.12 Yes Fig.11 A three-dimensional image of the sealing plate after it is turned over. Fig.12 The sealing plate 14 is shown on the side (inner side) of the outer body 12. Figure 10 to Figure 12 As shown, the positive electrode first current collecting portion 51 is mounted on the inner surface of the sealing plate 14. The positive electrode first current collecting portion 51 has a first region 51a and a second region 51b. The positive electrode first current collecting portion 51 can be formed by bending a single component by, for example, stamping, or by integrating a plurality of components by welding. Here, the positive electrode first current collecting portion 51 is fixed to the sealing plate 14 by riveting.

[0099] The first region 51a is a portion disposed between the sealing plate 14 and the electrode assembly 20. The first region 51a extends along the longitudinal direction Y. The first region 51a extends horizontally along the inner surface of the sealing plate 14. A positive electrode insulating member 70 is disposed between the sealing plate 14 and the first region 51a. The first region 51a is insulated from the sealing plate 14 by the positive electrode insulating member 70. Here, the first region 51a is electrically connected to the positive terminal 30 by riveting. In the first region 51a, a through hole 51h is formed in the position corresponding to the terminal lead-out hole 18 of the sealing plate 14, which passes through in the up-down direction Z. The second region 51b is a portion disposed between the short side wall 12c of the outer body 12 and the electrode assembly 20. The second region 51b extends from one end portion ( Fig.10 The second region 51b extends along the up-down direction Z.

[0100] The positive electrode second current collecting portion 52 extends along the short side wall 12c of the outer casing 12. Figure 6 As shown, the second collector portion 52 of the positive electrode has a collector plate connection portion 52a, an inclined portion 52b and a tab joint portion 52c. The collector plate connection portion 52a is a portion electrically connected to the first collector portion 51 of the positive electrode. The collector plate connection portion 52a extends along the up-down direction Z. The collector plate connection portion 52a is arranged approximately perpendicular to the winding axis WL of the wound electrode body 20a, 20b, 20c. A recess 52d having a thickness thinner than its surroundings is provided in the collector plate connection portion 52a. A through hole 52e penetrating in the short side direction X is provided in the recess 52d. A joint portion with the first collector portion 51 of the positive electrode is formed in the through hole 52e. The joint portion is, for example, a welded joint portion formed by welding such as ultrasonic welding, resistance welding, laser welding, etc. A fuse may also be provided in the second collector portion 52 of the positive electrode.

[0101] The tab joint 52c is a portion attached to the positive tab group 23 and electrically connected to the plurality of positive tabs 22t. Figure 5 , Figure 6 As shown, the tab joint portion 52c extends along the vertical direction Z. The tab joint portion 52c is arranged substantially perpendicular to the winding axis WL of the wound electrode bodies 20a, 20b, and 20c. The surface of the tab joint portion 52c connected to the plurality of positive electrode tabs 22t is arranged substantially parallel to the short side wall 12c of the outer casing 12. Figure 4As shown, the tab joint 52c is formed with a joint J with the positive tab group 23. The joint J is, for example, a welded joint formed by welding such as ultrasonic welding, resistance welding, laser welding, etc., while the plurality of positive tabs 22t are overlapped. The welded joint is arranged so that the plurality of positive tabs 22t are close to one side of the short side direction X of the wound electrode bodies 20a, 20b, and 20c. As a result, the plurality of positive tabs 22t can be bent more appropriately and stably. Figure 4 The positive electrode tab group 23 has a bent shape as shown. The tab joint portion 52c is an example of a tab connection surface.

[0102] The inclined portion 52b is a portion connecting the lower end of the collector plate connection portion 52a and the upper end of the tab joint portion 52c. The inclined portion 52b is inclined relative to the collector plate connection portion 52a and the tab joint portion 52c. The inclined portion 52b connects the collector plate connection portion 52a and the tab joint portion 52c in such a manner that the collector plate connection portion 52a is located closer to the center side than the tab joint portion 52c in the long side direction Y. Thus, it is possible to expand the accommodation space of the electrode body group 20 and realize a high energy density of the battery 100. Preferably, the lower end of the inclined portion 52b (in other words, the end on the bottom wall 12a side of the outer body 12) is located below the lower end of the positive electrode tab group 23. Thus, the plurality of positive electrode tabs 22t can be more appropriately bent and can be stably formed. Figure 4 The positive electrode tab group 23 has a bent shape as shown.

[0103] The negative electrode current collecting portion 60 constitutes a conduction path that electrically connects the negative electrode tab group 25 and the negative electrode terminal 40, wherein the negative electrode tab group 25 is composed of a plurality of negative electrode tabs 24t. Figure 2 As shown, the negative electrode current collecting portion 60 includes a negative electrode first current collecting portion 61 and a negative electrode second current collecting portion 62. The negative electrode first current collecting portion 61 and the negative electrode second current collecting portion 62 can be made of the same metal type as the negative electrode current collector 24c, for example, conductive metals such as copper, copper alloy, nickel, and stainless steel. The structures of the negative electrode first current collecting portion 61 and the negative electrode second current collecting portion 62 can be the same as the positive electrode first current collecting portion 51 and the positive electrode second current collecting portion 52 of the positive electrode current collecting portion 50. The negative electrode current collecting portion 60 is an example of a current collecting portion, and the negative electrode second current collecting portion 62 is an example of a tab connection surface.

[0104] like Fig.12 As shown, the negative electrode first current collecting portion 61 has a first region 61a and a second region 61b. A negative electrode insulating member 80 is disposed between the sealing plate 14 and the first region 61a. The negative electrode insulating member 80 insulates the first region 61a from the sealing plate 14. In the first region 51a, a through hole 61h is formed at a position corresponding to the terminal lead-out hole 19 of the sealing plate 14 and extending in the vertical direction Z. Figure 6As shown, the negative electrode second current collector 62 has a current collector plate connection portion 62a electrically connected to the negative electrode first current collector 61, an inclined portion 62b, and a tab joint portion 62c attached to the negative electrode tab group 25 and electrically connected to the plurality of negative electrode tabs 24t. The current collector plate connection portion 62a has a recessed portion 62d connected to the tab joint portion 62c. A through hole 62e penetrating in the short side direction X is provided in the recessed portion 62d.

[0105] The positive electrode insulating member 70 is a member that insulates the sealing plate 14 from the positive electrode first current collecting portion 51. The positive electrode insulating member 70 is made of a resin material that has tolerance and electrical insulation to the electrolyte used and is elastically deformable, and is preferably made of, for example, polyolefin resins such as polypropylene (PP), fluororesins such as tetrafluoroethylene-perfluoroalkoxy vinyl ether copolymer (PFA), polyphenylene sulfide (PPS), etc.

[0106] like Figure 2 As shown, the positive electrode insulating member 70 has a base 70a and a plurality of protrusions 70b. Here, the base 70a and the protrusions 70b are integrally formed. Here, the positive electrode insulating member 70 is an integrally formed part formed by integrally forming the above-mentioned resin material. Thus, compared with the case where the base 70a and the protrusions 70b are set as different components, the number of components used can be reduced, and low cost can be achieved. In addition, the positive electrode insulating member 70 can be prepared more simply.

[0107] The base portion 70a is a portion disposed between the sealing plate 14 and the first region 51a of the positive electrode first current collecting portion 51 in the vertical direction Z. The base portion 70a extends horizontally along the first region 51a of the positive electrode first current collecting portion 51. Fig.10 As shown, the base portion 70 a has a through hole 70 h penetrating in the up-down direction Z. The through hole 70 h is formed at a position corresponding to the terminal lead-out hole 18 of the sealing plate 14 .

[0108] The plurality of protrusions 70b protrude toward the electrode assembly 20 side relative to the base 70a. Fig.12 As shown, in the longitudinal direction Y, the plurality of protrusions 70b are provided closer to the center side of the sealing plate 14 than the base 70a ( Fig.12 The plurality of protrusions 70b are arranged in a row in the short side direction X. Figure 3 As shown, the plurality of protrusions 70b are formed in a substantially U-shaped cross section. Here, the plurality of protrusions 70b face the bent portions 20r of the wound electrode bodies 20a, 20b, and 20c constituting the electrode assembly group 20. Thus, it is possible to prevent the end faces of the wound electrode bodies 20a, 20b, and 20c from being pressed and damaged by the protrusions 70b.

[0109] Here, the number of protrusions 70b is the same as the number of wound electrode bodies 20a, 20b, 20c constituting the electrode body group 20. That is, three. As a result, the wound electrode bodies 20a, 20b, 20c and the protrusions 70b can be more reliably opposed to each other, and the effect of the technology disclosed herein can be better exerted. In addition, the wound electrode bodies 20a, 20b, 20c can be brought into contact with the protrusions 70b in a well-balanced manner in the insertion process described later. However, the number of protrusions 70b can be different from the number of electrode bodies constituting the electrode body group 20, for example, it can be one.

[0110] like Figure 2 As shown, the negative electrode insulating member 80 is arranged symmetrically with the positive electrode insulating member 70 with respect to the center CL in the longitudinal direction Y of the electrode assembly 20. The structure of the negative electrode insulating member 80 may be the same as that of the positive electrode insulating member 70. Here, similarly to the positive electrode insulating member 70, the negative electrode insulating member 80 has a base 80a and a plurality of protrusions 80b arranged between the sealing plate 14 and the negative electrode first current collecting portion 61.

[0111] <Method of Manufacturing Battery 100>

[0112] The manufacturing method of the battery 100 is characterized by using the positive electrode 22 and / or the negative electrode 24 as described above. The manufacturing process is the same as before. In addition to the positive electrode 22 and / or the negative electrode 24 as described above, the separator 26, the battery case 10 (the outer body 12 and the sealing plate 14), the electrolyte, the positive terminal 30, the negative terminal 40, the positive electrode collector 50 (the first positive electrode collector 51 and the second positive electrode collector 52), the negative electrode collector 60 (the first negative electrode collector 61 and the second negative electrode collector 62), the positive electrode insulating member 70, and the negative electrode insulating member 80 are prepared. For example, the battery 100 can be manufactured by a manufacturing method that sequentially includes a winding process, a first installation process, a second installation process, an insertion process, and a sealing process. In addition, the manufacturing method disclosed herein may further include other processes at any stage.

[0113] In the winding process, Figure 7A wound electrode body 20a having a strip-shaped positive electrode 22, a strip-shaped negative electrode 24 and a strip-shaped separator 26 as shown. Specifically, first, a winding device is prepared, wherein the winding device includes a winding unit that stacks the positive electrode 22, the negative electrode 24 and the separator 26 and winds them in a winding direction, and a cutting unit that cuts the strip-shaped positive electrode 22 and / or the negative electrode 24 into a predetermined length (winding length). The cutting unit includes a detection device and a cutting portion as described above. Next, the front end portions of the two strip-shaped separators 26 are fixed to the winding core of the winding unit. That is, the two separators 26 are clamped by the winding core. Next, a strip-shaped positive electrode 22 provided with a plurality of positive electrode tabs 22t and a strip-shaped negative electrode 24 provided with a plurality of negative electrode tabs 24t are prepared. The plurality of positive electrode tabs 22 t and / or the plurality of negative electrode tabs 24 t include a detection tab 27 having a predetermined straight portion 27S and a plurality of normal tabs 28 a to 28 e having no predetermined straight portion 27S.

[0114] Next, the winding core is rotated while supplying the strip-shaped positive electrode 22 and the strip-shaped negative electrode 24, and the positive electrode 22 and the negative electrode 24 are wound through the separator 26. At this time, the position of the straight portion 27S provided on the detection tab 27 is detected by the detection device of the cutting unit, and is set as the reference position. The detection device is, for example, a laser detection device having an emitting unit for emitting laser light and a light receiving unit for receiving the laser light from the emitting unit. Then, the positive electrode 22 and the negative electrode 24 are cut at the cutting position located at the predetermined winding length from the reference position by the cutting unit.

[0115] Fig.13 2 is a schematic top view of the positive electrode 22 during the winding process. Fig.13 As shown by the imaginary line in , during the winding process, the positive electrode 22 sometimes moves in the height direction Y and a winding deviation occurs. However, in the technology disclosed herein, the detection tab 27 is included in the plurality of positive tabs 22t. Therefore, even when a winding deviation occurs, the position of the detection tab 27 detected by the detection device is difficult to change in the length direction W. As a result, at the cutting position (1) and the cutting position (2), the cutting positions are aligned, and the positive electrode 22 can be cut at an accurate position. Therefore, it is possible to suppress the position deviation of the plurality of positive tabs 22t in the short side direction X in the battery 100, and appropriately form a positive tab group 23 in which the positive tabs 22t are brought together.

[0116] In the first installation process, make Fig.11 , Fig.12 Specifically, first, the positive electrode terminal 30 , the positive electrode first current collecting portion 51 , the positive electrode insulating member 70 , the negative electrode terminal 40 , the negative electrode first current collecting portion 61 , and the negative electrode insulating member 80 are attached to the sealing plate 14 .

[0117] The positive electrode terminal 30, the positive electrode first current collecting portion 51, and the positive electrode insulating member 70 are fixed to the sealing plate 14 by, for example, riveting. Fig.10 As shown, a gasket 90 is clamped between the outer surface of the sealing plate 14 and the positive terminal 30, and a positive insulating component 70 is further clamped between the inner surface of the sealing plate 14 and the positive first current collecting part 51 and riveted. In addition, the material of the gasket 90 can be the same as that of the positive insulating component 70. In detail, the positive terminal 30 before riveting is inserted into the through hole 90h of the gasket 90, the terminal lead-out hole 18 of the sealing plate 14, the through hole 70h of the positive insulating component 70 and the through hole 51h of the positive first current collecting part 51 from the top of the sealing plate 14, and is made to protrude to the bottom of the sealing plate 14. Then, the portion of the positive terminal 30 that protrudes below the sealing plate 14 is riveted in a manner that applies a compressive force relative to the up-down direction Z. As a result, at the front end portion ( Figure 2 The lower end portion of the rivet portion 30c is formed.

[0118] By such riveting, the gasket 90, the sealing plate 14, the positive electrode insulating member 70 and the positive electrode first current collecting portion 51 are integrally fixed to the sealing plate 14, and the terminal lead-out hole 18 is sealed. In addition, the riveted portion 30c may also be welded to the positive electrode first current collecting portion 51. Thus, the conduction reliability can be further improved.

[0119] The fixing of the negative terminal 40, the negative first current collecting part 61 and the negative insulating member 80 can be performed in the same manner as the above-mentioned positive electrode side. That is, the negative terminal 40 before riveting is inserted into the through hole of the gasket, the terminal lead-out hole 19 of the sealing plate 14, the through hole of the negative insulating member 80 and the through hole of the negative first current collecting part 61 in sequence from the top of the sealing plate 14, and is made to protrude downward from the sealing plate 14. Then, the portion of the negative terminal 40 that protrudes below the sealing plate 14 is riveted in a manner that applies a compressive force relative to the up-down direction Z. As a result, at the front end portion ( Figure 2 The lower end portion of the rivet portion 40c is formed.

[0120] Next, the positive electrode external conductive member 32 and the negative electrode external conductive member 42 are mounted on the outer surface of the sealing plate 14 via the external insulating member 92. In addition, the material of the external insulating member 92 may be the same as that of the positive electrode insulating member 70. In addition, the timing of mounting the positive electrode external conductive member 32 and the negative electrode external conductive member 42 may be after the insertion process (for example, after the injection hole 15 is sealed).

[0121] In the second installation step, the first combined object produced in the first installation step is used to produce Figure 5 Specifically, first, as shown in Figure 6As shown in FIG. 1 , three wound electrode bodies 20a with the positive electrode second current collecting portion 52 and the negative electrode second current collecting portion 62 are prepared as wound electrode bodies 20a, 20b, and 20c, and arranged in the short side direction X. In this case, the wound electrode bodies 20a, 20b, and 20c can all be arranged with the positive electrode second current collecting portion 52 arranged on one side in the long side direction Y ( Figure 5 The negative electrode second current collecting portion 62 is arranged on the other side in the longitudinal direction Y ( Figure 5 The two pieces are arranged side by side in a manner similar to the right side of the figure.

[0122] Then, if Figure 4 As shown, the positive first collector 51 (more specifically, the second region 51b) fixed to the sealing plate 14 and the positive second collector 52 (more specifically, the collector plate connection portion 52a) of the wound electrode body 20a, 20b, 20c are respectively joined while the plurality of positive electrode tabs 22t are bent. In addition, the negative first collector 61 fixed to the sealing plate 14 and the negative second collector 62 of the wound electrode body 20a, 20b, 20c are respectively joined while the plurality of negative electrode tabs 24t of the negative electrode tab group 25 are bent. As a joining method, for example, ultrasonic welding, resistance welding, laser welding, and the like can be used. It is particularly preferred to use welding performed by irradiation with high-energy lines such as lasers. By such welding processing, a joining portion is formed in the recess 52d of the positive second collector 52 and the recess 62d of the negative second collector 62, respectively.

[0123] In the inserting step, the electrode assembly 20 integrated with the sealing plate 14 is accommodated in the internal space of the outer casing 12 . Fig.14 : is a schematic cross-sectional view for explaining the insertion process. Specifically, first, for example, an insulating resin sheet made of a resin material such as polyethylene (PE) is bent into a bag or box shape to prepare an electrode body holder 29. Next, the electrode body group 20 is accommodated in the electrode body holder 29. Then, the electrode body group 20 covered with the electrode body holder 29 is inserted into the outer casing 12. In the case where the weight of the electrode body group 20 is heavy, in the case of approximately 1 kg or more, for example, 1.5 kg or more, and further 2 to 3 kg, it can be as follows Fig.14 As shown, the electrode assembly 20 is inserted into the outer casing 12 so that the long side wall 12 b of the outer casing 12 intersects the gravity direction (the outer casing 12 is oriented horizontally).

[0124] The bent portions 20r of the wound electrode bodies 20a, 20b, and 20c constituting the electrode body group 20 are pressed by the protrusions 70b of the positive electrode insulating member 70 and / or the protrusions 80b of the negative electrode insulating member 80, respectively, and are pushed into the interior of the outer casing 12. By pushing the electrode body group 20 with the protrusions 70b and / or the protrusions 80b, the load on the positive electrode tab group 23 and / or the negative electrode tab group 25, especially the load applied to the base vicinity of the positive electrode tab 22t, can be reduced.

[0125] The positive electrode tab group 23 and / or the negative electrode tab group 25 have a clearance that allows them to move in a direction intersecting the protruding direction (typically the vertical direction Z). Therefore, after the electrode assembly 20 is inserted into the outer casing 12, when the outer casing 12 is lifted up so that the sealing plate 14 is brought to the top, the electrode assembly 20 moves slightly downward due to gravity. Figure 3 As shown, the protrusion 70b of the positive electrode insulating member 70 and the wound electrode bodies 20a, 20b, 20c are arranged at separate positions. Also, the protrusion 80b of the negative electrode insulating member 80 and the wound electrode bodies 20a, 20b, 20c are arranged at separate positions.

[0126] In the sealing step, the sealing plate 14 is joined to the edge of the opening 12h of the outer body 12 to seal the opening 12h. The sealing plate 14 can be joined by welding such as laser welding, for example. Thereafter, the electrolyte is injected from the injection hole 15, and the injection hole 15 is blocked by the sealing member 16, so that the battery 100 is sealed.

[0127] The battery 100 can be manufactured in this way.

[0128] The battery 100 can be used for various purposes, for example, it can be preferably used as a power source (driving power source) for a motor mounted on a vehicle such as a car or a truck. The type of vehicle is not particularly limited, and examples thereof include a plug-in hybrid vehicle (PHV), a hybrid vehicle (HV), an electric vehicle (EV), etc. The battery 100 can be preferably used for the construction of a battery pack.

[0129] Some embodiments of the technology disclosed herein are described above, but the above embodiment is only an example. The technology disclosed herein can also be implemented in various ways. The technology disclosed herein can be implemented based on the contents disclosed in this specification and the technical common sense in this field. The technology described in the claims includes technologies that are variously deformed and changed from the above-mentioned exemplified embodiments. For example, part of the above-mentioned embodiment can be replaced with other variations, and other variations can be added to the above-mentioned embodiment. In addition, as long as the technical feature is not described as a necessary feature, it can be appropriately deleted.

[0130] For example, in the above-mentioned embodiment, the detection tab 27 is a pentagon and has one straight portion 27S. The straight portion 27S constitutes a portion of the side extending from the base in the height direction Y and being the starting end side W1. However, it is not limited to this. The shape of the detection tab 27 may also be a quadrilateral such as a square, a rectangle, a right-angled trapezoid, etc. In addition, one detection tab 27 may have a plurality of straight portions 27S. Figures 15A to 15D The schematic plan views respectively show detection tabs 127 , 227 , 327 , and 427 according to modified examples.

[0131] Fig.15A The detection tab 127 shown is rectangular and has a pair of (two) straight line portions 127S. Fig. 15B , Fig. 15C The detection tabs 227 and 327 shown are right-angled trapezoids. The detection tabs 227 and 327 have a straight portion 227S and 327S respectively. Fig. 15B In the detection tab 227 shown in the figure, the side extending from the base in the height direction Y and on the starting end side W1 is composed of a straight line portion 227S. Fig. 15C In the detection tab 327 shown, the side extending from the base in the height direction Y and on the terminal side W2 is constituted by a straight line portion 327S. Fig.15D The detection tab 427 shown is a pentagon. In the detection tab 427, the straight portion 427S constitutes a part of the side extending from the base in the height direction Y and on the terminal side W2.

[0132] In addition, for example, in the above embodiment, if Fig. 9 As shown, the detection tab 27 is arranged in a manner of one tab / layer. The dimensions (specifically, tab height) of the common tabs 28a to 28e are different from each other. Specifically, the common tabs 28a to 28e are arranged in a manner that the length in the long side direction Y gradually increases from one side of the short side direction X of the wound electrode body 20a toward the other side. However, this is not limited to this. Fig.16A , 16B 17A and 17B are schematic plan views showing positive electrodes 122 and 222 according to modified examples.

[0133] Fig.16A , 16B The positive electrode 122 shown has a plurality of common tabs 128. Fig.16A As shown in the top view of FIG. 1 , the plurality of common tabs 128 are all arranged with the same tab height Tf. When the positive electrode 122 is wound, as shown in FIG. Fig. 16B As shown in the partial cross-sectional view of , the lengths in the long-side direction Y are aligned. For example, when the positive electrode is arranged in the battery case 10 without bending the plurality of positive electrode tabs, such a mode can be appropriately adopted.

[0134] Fig.17A , 17B The positive electrode 222 shown has a plurality of common tabs 228a, 228b, 228c. Fig.17A As shown in the top view, the common pole tabs 228a, 228b, and 228c are arranged one by one in the area divided by the bending position B. The number of common pole tabs 228a, 228b, and 228c is half the number of layers of the positive electrode 22 (0.5 pole tabs / layer). That is, the number of common pole tabs 228a, 228b, and 228c is 2 pole tabs / number of windings (turns). Like the odd-numbered common pole tabs 28c and 28e of the positive electrode 22, the height of the pole tabs of the plurality of common pole tabs 228a, 228b, and 228c gradually increases from the starting side W1 toward the terminal side W2. When winding the positive electrode 222, as shown in FIG. Fig. 17B As shown in the partial cross-sectional view of FIG. , the length of the long side direction Y gradually becomes longer. Fig.17A In the positive electrode 222 shown, the tab height gradually increases from the starting end side W1 toward the terminal side W2 , but the tab height may gradually decrease from the starting end side W1 toward the terminal side W2 similarly to the normal tabs 28 b and 28 d of the positive electrode 22 .

[0135] In addition, for example, in the battery 100 of the above embodiment, a positive electrode protective layer 22p is formed on a portion of the positive electrode tab 22t (detection tab 27 and common tabs 28a to 28e), and a negative electrode active material layer 24a is formed on a portion of the negative electrode tab 24t. However, this is not limited to this. A positive electrode active material layer 22a may also be formed on a portion of the positive electrode tab 22t. Alternatively, the positive electrode tab 22t may be formed by an exposed portion of the positive electrode collector 22c, and the negative electrode tab 24t may be formed by an exposed portion of the negative electrode collector 24c.

Claims

1. A method for manufacturing a battery, in, The battery has: one or more wound electrode bodies, wherein a strip-shaped first electrode plate and a strip-shaped second electrode plate are stacked and wound via a strip-shaped separator; and a battery case, the battery case housing the wound electrode body, The first electrode plate has a plurality of electrode tabs protruding from an end side extending in a length direction. The plurality of electrode tabs include: A first electrode tab, wherein the first electrode tab has a straight portion, the straight portion is 90°±5° relative to the end edge, and the length of the straight portion in a direction perpendicular to the end edge is greater than 2 mm; as well as a second electrode tab, wherein the second electrode tab does not have the straight portion, The battery manufacturing method includes the following steps: detecting the straight portion of the first electrode tab, and cutting the first electrode plate at a position of a predetermined length away from the straight portion based on the detected position of the first electrode tab in the length direction of the first electrode plate.

2. The method for manufacturing a battery according to claim 1, in, At least one of the second electrode tabs has a length in a direction perpendicular to the length direction greater than that of the first electrode tab, and a root connected to the end edge has a length in the length direction greater than that of the first electrode tab.

3. The method for manufacturing a battery according to claim 1 or 2, in, At least one of the second electrode tabs has a shorter length in a direction perpendicular to the longitudinal direction than the first electrode tab, and a shorter length in the longitudinal direction of a root connected to the end edge than the first electrode tab.

4. The method for manufacturing a battery according to claim 1 or 2, in, The first electrode tab is arranged in an asymmetric shape in the length direction.

5. The method for manufacturing a battery according to claim 1 or 2, in, The first electrode tab has an inclined portion or a curved portion inclined with respect to the straight portion between a base connected to the end side and the straight portion in a direction perpendicular to the longitudinal direction.

6. The method for manufacturing a battery according to claim 5, in, The length of the first electrode tab from the base to the straight portion is 4 mm or more.

7. The method for manufacturing a battery according to claim 1 or 2, in, When a straight line passing through one end of the straight line portion in the direction in which the first electrode tab protrudes and extending in the longitudinal direction is defined as a straight line La, and a straight line passing through the other end of the straight line portion in the direction in which the first electrode tab protrudes and extending in the longitudinal direction is defined as a straight line Lb, The first electrode tab has a region between the straight line La and the straight line Lb having a length of 10 mm or more in the longitudinal direction and a length of 3 mm or more in a direction perpendicular to the longitudinal direction.

8. The method for manufacturing a battery according to claim 1 or 2, in, The battery housing comprises: an outer casing, the outer casing having a bottom wall, a pair of first side walls extending from the bottom wall and facing each other, a pair of second side walls extending from the bottom wall and facing each other, and an opening facing the bottom wall; as well as a sealing plate for sealing the opening of the outer body, The battery also has: an electrode terminal, the electrode terminal being fixed to the sealing plate; and a current collecting portion, the current collecting portion electrically connecting the electrode terminal and the first electrode tab, The plurality of electrode tabs are stacked at an end portion of the wound electrode body in a direction along the first side wall. The collector portion has a tab connection surface connected to the first electrode tab at an end portion along the first side wall.

9. The method for manufacturing a battery according to claim 1 or 2, in, The number of the wound electrode bodies is plural.

10. The method for manufacturing a battery according to claim 1 or 2, in, The number of the electrode tabs is greater than 0.8 relative to the number of layers of the first electrode plate.

11. The method for manufacturing a battery according to claim 1 or 2, in, The second electrode plate has a plurality of electrode tabs protruding from an end side extending in the length direction. The plurality of electrode tabs of the second electrode plate include: a first electrode tab, wherein the first electrode tab has a straight portion, the straight portion is 90°±5° relative to the end edge, and the length of the straight portion in a direction perpendicular to the end edge is greater than 2 mm; and a second electrode tab, wherein the second electrode tab does not have the straight portion, The battery manufacturing method includes the following steps: detecting the straight portion of the first electrode tab of the second electrode plate, and cutting the second electrode plate at a position of a predetermined length away from the straight portion of the second electrode plate based on the detected position of the first electrode tab of the second electrode plate in the length direction.

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