JP2019091563A - Power storage element - Google Patents

Abstract

To provide a power storage element in which the occurrence of a damage to an electrode body attributed to a protection plate can be suppressed by sandwiching the electrode body by the protection plate and a current collector.SOLUTION: A power storage element comprises: an electrode body 2 arranged by laminating electrodes each including a covered portion having an active material layer superposed on metal foil and an uncovered portion having metal foil extending from the metal foil of the covered portion and exposed from the active material layer in a thickness direction; a current collector 5 arranged over an uncovered laminate portion; and a protection plate 7 for holding the uncovered laminate portion from a side opposite to the current collector together with the current collector. The protection plate has a first part 71 and second parts 72. The first part abuts on the uncovered laminate portion, and extends in an array direction in which a covered laminate portion 26 where the covered portions are laminated, and the uncovered laminate portion are arrayed. The second part is one extending from the first part toward the covered laminate portion, excluding both end portions of the protection plate in a direction orthogonal to a lamination direction and the array direction, and curved toward a direction distant from the current collector with respect to the first part.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a storage element in which an electrode body and a current collector are joined.

  Conventionally, a lithium ion secondary battery (hereinafter, simply referred to as "battery") in which a current extraction terminal is joined to an electrode body is known (see Patent Document 1). Specifically, as shown in FIG. 15, this battery has a wound electrode assembly 102 formed by winding an electrode plate, and a current extraction terminal 105 for extracting current from the wound electrode assembly 102. The electrode plate of the wound electrode assembly 102 is composed of a positive electrode plate and a negative electrode plate disposed via a separator. The current extraction terminal 105 is joined to the uncoated portion of the wound electrode body 102 to which the active material is not applied.

  The current extraction terminal 105 is bonded to the wound electrode assembly 102 by ultrasonic bonding. The ultrasonic bonding is performed in a state where the wound electrode assembly 102 is superimposed on the current lead terminal 105 disposed on the anvil 181 of the ultrasonic welder, and the buffer plate 107 is further disposed. As described above, the current extraction terminal 105 is wound by applying ultrasonic vibration by the horn 180 of the ultrasonic welding machine in a state where the current extraction terminal 105, the wound electrode assembly 102, and the buffer plate 107 are superimposed. It is joined to the circular electrode body 102.

  When the current extraction terminal 105 is joined to the wound electrode assembly 102 in a state where the wound electrode assembly 102 is sandwiched between the current extraction terminal 105 and the buffer plate 107 as described above, the buffer plate 107 becomes the wound electrode assembly 102. By pressing, the wound electrode assembly 102 may bend toward the opposite side of the sandwiching direction. At this time, if a bent portion or the like of the wound electrode body 102 is pressed by a portion such as a corner of the buffer plate 107 with a large force, the portion such as the corner may damage the electrode plate 102.

JP 2001-38475 A

  So, this embodiment aims at providing the electrical storage element which suppressed generation | occurrence | production of the damage of the electrode body by the protective plate by an electrode body being pinched | interposed by a protective plate and a collector.

The storage element of the present embodiment is
An electrode including a metal foil and a coated portion having an active material layer overlapping the metal foil and a non-coated portion having a metal foil extended from the metal foil of the coated portion and exposed from the active material layer is laminated in the thickness direction Electrode body, and
A current collector which is stacked in the stacking direction of the electrode with respect to the non-coating laminated portion in which the non-coating portion is laminated;
And a protective plate sandwiching the non-coated laminated portion with the current collector from the opposite side of the current collector in the stacking direction.
The protective plate is
A first portion that abuts on the uncoated laminate portion and extends in the alignment direction of the coated laminate portion on which the coated portion is laminated and the uncoated laminate portion;
A second portion extending from the first portion to the coated laminated portion and excluding both end portions of the protective plate in a direction orthogonal to both the laminating direction and the arranging direction, which is the second portion from the current collector And a second portion that is curved with respect to the first portion in a direction away from.

  According to this configuration, the portion covering the bent portion of the electrode body in the protective plate (the portion bent by being pressed by the curved protective plate of the electrode body) is more angular than the edge of the protective plate Even if the protective plate presses the uncoated laminate, the uncoated laminate is less likely to be damaged. In addition, since the second portion is bent along the electrode body, the tip of the second portion (the coated laminated portion side in the direction in which the second portion is arranged) in comparison with a configuration in which the protective plate is not bent with respect to the electrode body Since the front end of the) can not strongly press the non-coated laminate portion, it is possible to suppress the occurrence of damage to the non-coated laminate portion by the front end of the second portion. Therefore, the occurrence of damage to the electrode body by the protective plate can be suppressed.

In the storage element,
The portions on both sides of the first portion and the second portion in the direction orthogonal to both the stacking direction and the arranging direction are surfaces of the non-covered laminated portion due to elastic recovery force generated by elastic deformation. You may press on the said collector side in the lamination direction.

  According to this configuration, due to the elastic recovery force of the protective plate, for example, the protective plate holds the periphery of the bonding site with the current collector in the non-coated laminated portion, thereby causing some load (for example, vibration or impact) to the electrode body. When generated, the load applied to the joint portion in the electrode assembly can be reduced, and the occurrence of damage can be suppressed.

  According to the storage element of the present embodiment, it is possible to provide a storage element in which the occurrence of damage to the electrode body by the protection plate is suppressed when the electrode body is sandwiched by the protection plate and the current collector.

FIG. 1 is a perspective view of a storage element according to the present embodiment. FIG. 2 is an exploded perspective view of the storage element. FIG. 3 is a view for explaining an electrode body of the storage element. FIG. 4 is a cross-sectional view taken along line IV-IV of FIG. FIG. 5 is a cross-sectional view of the vicinity of the bonding point between the electrode body and the current collector. 6 is an enlarged view of a cross-sectional view taken along the line VI-VI of FIG. FIG. 7 is a view for explaining a method of bonding the electrode body and the current collector. FIG. 8 is a schematic cross-sectional view taken along line VIII-VIII of FIG. 7 before the protective plate is placed in the uncoated laminate. FIG. 9 is a schematic cross-sectional view at a VIII-VIII position of FIG. 7 in a state in which the protective plate is disposed in the uncoated laminate portion. FIG. 10 is a schematic view for explaining the bending of the protective plate. FIG. 11 is a schematic view of the protective plate. FIG. 12 is a schematic view for explaining ultrasonic bonding of the electrode body and the current collector. FIG. 13 is a schematic view for explaining ultrasonic bonding of the electrode body and the current collector. FIG. 14 is a perspective view of a power storage device including the power storage element. FIG. 15 is a schematic view for explaining a method of bonding a conventional wound electrode body and a current lead terminal.

  Hereinafter, an embodiment of a storage element according to the present invention will be described with reference to FIGS. 1 to 13. The storage element according to the present embodiment includes a primary battery, a secondary battery, a capacitor, and the like. In the present embodiment, a chargeable / dischargeable secondary battery will be described as an example of a storage element. Below, the structure of the electrical storage element manufactured by the manufacturing method which concerns on this embodiment is demonstrated first, and the manufacturing method of an electrical storage element is demonstrated after that. In addition, the name of each component (each component) of this embodiment is in this embodiment, and may differ from the name of each component (each component) in background art.

  The storage element according to the present embodiment is a non-aqueous electrolyte secondary battery. More specifically, the storage element is a lithium ion secondary battery utilizing electron transfer that occurs as lithium ion moves. This type of storage element supplies electrical energy. The storage element is used singly or in plurality. Specifically, the storage element is used singly when the required output and the required voltage are small. On the other hand, when at least one of the required output and the required voltage is large, the storage element is used in the storage device in combination with another storage element. In the storage device, a storage element used for the storage device supplies electrical energy.

  As shown in FIGS. 1 to 4, the storage element includes an electrode body 2, a case 3 accommodating the electrode body 2, an external terminal 4 at least a portion of which is exposed to the outside of the case 3, an electrode body 2 and an external body And a current collector 5 electrically connected to the terminal 4. The storage element 1 also includes an insulating member 6 and the like disposed between the electrode body 2 and the case 3. The storage element 1 of the present embodiment includes a protective plate 7 that protects the electrode assembly 2 when the electrode assembly 2 and the current collector 5 are bonded.

  The electrode body 2 has stacked electrodes (positive electrode 23 and negative electrode 24). Specifically, the electrode body 2 is a laminated body 22 in which the winding core 21 and the positive electrode 23 and the negative electrode 24 are laminated in a mutually insulated state, and the laminated body 22 is wound around the winding core 21. And (see FIGS. 3 and 4). When lithium ions move between the positive electrode 23 and the negative electrode 24 in the electrode body 2, the storage element 1 is charged and discharged.

  The winding core 21 is usually formed of an insulating material. The winding core 21 of the present embodiment is cylindrical, more specifically, flat and cylindrical. The winding core 21 is formed by winding a flexible or thermoplastic sheet. The sheet of the present embodiment is formed of a synthetic resin.

  The positive electrode 23 has a coated portion 232 coated with the active material layer, and a non-coated portion 231 extending from the coated portion 232 and not coated with the active material layer. Specifically, the positive electrode 23 has a strip-shaped metal foil and a positive electrode active material layer stacked on the metal foil. In this positive electrode 23, an uncoated portion (a portion where the positive electrode active material layer is not formed) 231 is formed on one edge of the width direction which is the short direction, in which the metal foil is not coated with the positive electrode active material layer. In the remaining portion in the width direction, the covering portion 232 in which the metal foil is covered with the positive electrode active material layer is formed. The metal foil which comprises the positive electrode 23 of this embodiment is an aluminum foil, for example.

  Like the positive electrode 23, the negative electrode 24 also has a coated portion 242 coated with the active material layer, and a non-coated portion 241 extending from the coated portion 242 and not coated with the active material layer. Specifically, the negative electrode 24 has a strip-shaped metal foil and a negative electrode active material layer superimposed on the metal foil. In the negative electrode 24, a non-coated portion (negative electrode active) in which a metal foil is not coated on the negative electrode active material layer at the other edge of the width direction (the opposite side to the non-coated portion 231 of the positive electrode 23) A portion where the material layer is not formed) 241 is formed, and a covering portion 242 in which the metal foil is coated on the negative electrode active material layer is formed on the remaining portion in the width direction. The metal foil which comprises the negative electrode 24 of this embodiment is a copper foil, for example.

  In the electrode body 2, the covering portions 232, 242 have a metal foil and an active material layer overlapping the metal foil, and the non-covering portions 231, 241 extend from the metal foil of the covering portions 232, 242 and The positive electrode 23 and the negative electrode 24 having a metal foil exposed from the layer are laminated in the thickness direction. In the electrode body 2 of the present embodiment, the positive electrode 23 and the negative electrode 24 configured as described above are wound in a state of being insulated by the separator 25. Thus, in the electrode assembly 2 in which the positive electrode 23 and the negative electrode 24 are wound, the coated portions 232 of the positive electrode 23 are stacked, and the non-coated portions 231 of the positive electrode are stacked. Further, the coated portions 242 of the negative electrode 24 are stacked, and the non-coated portions 241 of the negative electrode 24 are stacked. In the electrode body 2, the covering portions 232 of the positive electrode 23 and the covering portions 242 of the negative electrode 24 are alternately stacked via the separators 25.

  The separator 25 is a member having an insulating property, and is disposed between the positive electrode 23 and the negative electrode 24. Thereby, the positive electrode 23 and the negative electrode 24 are mutually insulated in the electrode body 2 (specifically, the laminate 22). Further, the separator 25 holds the electrolytic solution in the case 3. Thereby, at the time of charge and discharge of the storage element 1, lithium ions can move between the positive electrode 23 and the negative electrode 24 alternately stacked with the separator 25 interposed therebetween.

The separator 25 is in the form of a band, and is made of, for example, a porous film of polyethylene, polypropylene, cellulose, polyamide or the like. In the separator 25 of the present embodiment, an inorganic layer containing inorganic particles such as SiO ₂ particles, Al ₂ O ₃ particles, boehmite (alumina hydrate) and the like is provided on a substrate formed of a porous film. It is formed of The base material of the separator 25 of the present embodiment is formed of, for example, polyethylene.

  The dimension in the width direction of the separator 25 is larger than the width of the negative electrode active material layer. The separator 25 is disposed between the positive electrode 23 and the negative electrode 24 stacked in a state where the covering portion 232 of the positive electrode 23 and the covering portion 242 of the negative electrode 24 are misaligned in the width direction such that they overlap in the thickness direction (stacking direction). Be placed. At this time, the non-coated portion 231 of the positive electrode 23 protrudes in the width direction (direction orthogonal to the stacking direction) from the overlapping region of the positive electrode 23 and the negative electrode 24, and the non-coated portion 241 of the negative electrode 24 It projects in the width direction (the direction opposite to the direction in which the non-covering portion 231 of the positive electrode 23 protrudes) from the overlapping region with 24. The electrode body 2 is formed by winding the positive electrode 23, the negative electrode 24, and the separator 25 stacked in such a state.

  In the electrode body 2 of the present embodiment, the coated and laminated portion 26 of the electrode body 2 is configured by a portion where the covering portion 232 of the positive electrode 23 and the covering portion 242 of the negative electrode 24 are laminated via the separator 25. Further, in the electrode body 2, the non-coated laminated portion 27 of the electrode body 2 is configured by a portion where only the non-coated portion 231 of the positive electrode 23 or the non-coated portion 241 of the negative electrode 24 is stacked.

  The non-coated laminated portion 27 is a portion electrically connected to the current collector 5 in the electrode body 2. The uncoated laminate portion 27 of the present embodiment has two portions (see FIG. 3) across the hollow portion 28 (see FIG. 3) as viewed from the wound central axis C direction of the wound positive electrode 23, negative electrode 24 and separator 25. (Divided uncoated laminated part) 271 is divided.

  The non-coated laminated portion 27 configured as described above is provided on each electrode of the electrode body 2. That is, a portion of the positive electrode 23 on which only the non-coated portion 231 is laminated constitutes the non-coated laminated portion 27 of the positive electrode in the electrode body 2 and a portion on which the non-coated portion 241 of the negative electrode 24 is laminated is the negative electrode in the electrode body 2 The uncoated laminated portion 27 of the

  In the electrode body 2 of the present embodiment, the end face 29 on the side of the protective plate 7 in the stacking direction of the electrode body 2 in each non-covered laminated portion 27 is the alignment direction of the covered portion 232 and the uncovered portion 231; And a second surface 292 extending from a tip 290 of the first surface 291 (see FIGS. 4 and 5). ). Here, that the first surface 291 extends in the first direction means that the first surface 291 extends in the first direction in a cross section in a plane including the stacking direction of the electrodes and the first direction.

  The second surface 292 is located on the side of the cover laminate portion 26 with respect to the first surface 291. In addition, the second surface 292 is farther from the current collector 5 in the stacking direction as the second surface 292 is farther from the tip 290 in the first direction. In other words, the second surface 292 is inclined toward the protective plate 7 in the stacking direction with respect to the extending direction (first direction) of the first surface 291. Further, the end face 29 of the present embodiment is a second direction (second direction which is a width direction of the electrode) orthogonal to any of the stacking direction and the first direction (the alignment direction of the covering portion 232 and the non-covering portion 231). And third surfaces 293 located on both sides of the first surface 291 (see FIG. 6). In addition, in the non-coated laminated portion 27 of the present embodiment, the second surface 292 and the third surface 293 of the portion excluding the bonding portion of the first surface 291 are smooth surfaces.

  Hereinafter, the first direction is the X axis of the orthogonal coordinate system, the stacking direction of the electrodes is the Y axis of the orthogonal coordinate system, and the second direction is the Z axis of the orthogonal coordinate system.

  The case 3 has a case body 31 having an opening, and a lid plate 32 that closes (closes) the opening of the case body 31 (see FIGS. 1 and 2). The case 3 accommodates the electrolytic solution in the inner space together with the electrode body 2 and the current collector 5 and the like. Case 3 is formed of a metal resistant to the electrolyte. The case 3 of the present embodiment is formed of, for example, an aluminum-based metal material such as aluminum or an aluminum alloy.

  The case 3 is formed by joining in a state where the opening peripheral edge portion 34 of the case main body 31 and the peripheral edge portion of the lid plate 32 are overlapped. In the case 3, an inner space is defined by the case body 31 and the lid plate 32.

  The case main body 31 includes a plate-like closing portion 311 and a cylindrical trunk portion (peripheral wall) 312 connected to the peripheral edge of the closing portion 311.

  The closing portion 311 is located at the lower end of the case body 31 when the case body 31 is disposed in the posture in which the opening is facing upward (that is, the bottom wall of the case body 31 when the opening faces upward). ) Site. The closed portion 311 has a rectangular shape when viewed from the normal direction of the closed portion 311.

  The body portion 312 has a square tube shape, more specifically, a flat square tube shape. The body portion 312 has a pair of long wall portions 313 extending from the long side in the peripheral edge of the closing portion 311 and a pair of short wall portions 314 extending from the short side in the peripheral edge of the closing portion 311. By connecting the short wall portions 314 to the corresponding end portions of the pair of long wall portions 313 (specifically, facing in the Y-axis direction), the rectangular cylindrical body portion 312 is formed.

  As described above, the case main body 31 has a rectangular tube shape (that is, a bottomed rectangular tube shape) in which one end in the opening direction (Z-axis direction) is closed. The electrode body 2 is accommodated in the case body 31 with the winding central axis C oriented in the X-axis direction (see FIG. 2).

  The cover plate 32 is a plate-like member that closes the opening of the case main body 31. Specifically, the contour of the lid plate 32 has a shape corresponding to the opening peripheral edge portion 34 of the case main body 31. The cover plate 32 of the present embodiment is a rectangular plate long in the X-axis direction. The cover plate 32 abuts on the case body 31 so as to close the opening of the case body 31. More specifically, the peripheral edge portion of the cover plate 32 is superimposed on the opening peripheral edge portion 34 of the case main body 31 so that the cover plate 32 closes the opening. The boundary between the cover plate 32 and the case main body 31 is welded in a state where the opening peripheral portion 34 and the cover plate 32 are overlapped. This constitutes case 3.

  The external terminal 4 is a portion electrically connected to an external terminal of another storage element or an external device. The external terminal 4 is formed of a conductive member. For example, the external terminal 4 is formed of a highly weldable metal material such as an aluminum-based metal material such as aluminum or aluminum alloy, or a copper-based metal material such as copper or copper alloy. The external terminal 4 of the present embodiment is attached to the lid plate 32.

  The current collector 5 is disposed in the case 3 and is directly or indirectly connected to the electrode body 2 so as to be electrically conductive in a state of being stacked on the electrode body 2 (for example, the non-coated laminated portion 27) in the Y-axis direction. . Specifically, the current collector 5 is connected to the electrode body 2 by ultrasonic bonding. The current collector 5 of the present embodiment is disposed along the inner surface of the case 3. The current collector 5 is formed of a conductive member.

  Specifically, as shown in FIG. 2, the current collector 5 includes a first connection portion 51 connected to the external terminal 4 in a conductive manner, and a second connection portion 52 connected to the electrode body 2 in a conductive manner. And a bent portion 53 connecting the first connection portion 51 and the second connection portion 52. In the case 3, the bending portion 53 is disposed in the vicinity of the boundary between the lid plate 32 and the short wall portion 314, the first connection portion 51 extends from the bending portion 53 along the lid plate 32, and the second connection portion 52 is bent. It extends from the portion 53 along the short wall portion 314.

  The first connection portion 51 is a plate-like portion extending from the bending portion 53 along the inner surface of the case 3 (cover plate 32) in a state of being insulated from the case 3 (specifically, the lid plate 32).

  The second connection portion 52 has a bonding piece 522 which is overlapped (for example, in surface contact) with the non-coated laminated portion 27 of the electrode body 2. Specifically, the second connection portion 52 has a main body 521 extending from the bending portion 53 along the case 3, and at least one joining piece 522 extending from the main body 521 and joined to the electrode body 2. The second connection portion 52 of the present embodiment has two joint pieces 522.

  The main body 521 extends along the short wall portion 314 from the bending portion 53 to the vicinity of the closing portion 311 or the closing portion 311 in a state of being insulated from the short wall portion 314.

  Each of the two bonding pieces 522 is overlapped (for example, in surface contact) with one side of the uncoated laminated portion 27 of the electrode assembly 2 in the laminating direction (X-axis direction in FIG. 4) of the uncoated portions 231 and 241. ing). Each of the two bonding pieces 522 in the present embodiment is the non-covered laminated portion 27 from the hollow portion 28 side of the electrode body 2, that is, the inner peripheral surface side of the flat cylindrical electrode body 2 It is in surface contact with the part 271). Specifically, the joining piece 522 is a plate-like portion extending from the main body 521 toward the electrode body 2 (the non-covered laminated portion 27) and in the same direction (Z-axis direction) as the main body 521. The joining piece 522 is disposed substantially at the center of the main body 521 in the Z-axis direction.

  The two joining pieces 522 extend in the Z-axis direction on both sides (both sides in the Y-axis direction) of the opening 56 so as to define an opening 56 provided centrally in the Y-axis direction of the main body 521 (see FIG. 2) . That is, the second connection portion 52 of the present embodiment includes the joining piece 522 joined to one of the two divided non-covered laminated portions 271 in each of the non-covered laminated portions 271, and And a joining piece 522 connected to the other one of the two divided non-covered laminated portions 271. In the current collector 5 of the present embodiment, the opening 56 and the two bonding pieces 522 insert, for example, a cut in the Z-axis direction (longitudinal direction) in a strip plate extending in the Z-axis direction and twist both sides of the cut. Formed by

  The current collectors 5 configured as described above are respectively disposed on the positive electrode and the negative electrode of the storage element 1. In the storage element 1 of the present embodiment, in the case 3, the non-coated laminated portion 27 of the positive electrode and the non-coated laminated portion 27 of the negative electrode of the electrode body 2 are respectively disposed. The current collector 5 of the positive electrode and the current collector 5 of the negative electrode are formed of different materials. Specifically, the current collector 5 of the positive electrode is formed of, for example, aluminum or an aluminum alloy, and the current collector 5 of the negative electrode is formed of, for example, copper or a copper alloy.

  When connecting the current collector 5 to the electrode body 2 (for example, by ultrasonic bonding), the protective plate 7 is used to form the electrode body (specifically, the uncoated portions 231 and 241 that constitute the uncoated laminated portion 27). It is a member to protect. Further, the protective plate 7 sandwiches the electrode body 2 together with the current collector 5 from the opposite side of the current collector 5 in the Y-axis direction.

  Furthermore, for example, the protective plate 7 is in surface contact with the non-coated laminated portion 27 of the electrode body 2 from the side opposite to the side where the bonding piece 522 is disposed in the Y-axis direction (see FIG. 4). In the example of the present embodiment, the non-coated laminated portion 27 (specifically, the divided non-coated laminated portion 271) is in surface contact with the outside of the electrode body 2, that is, the outer peripheral surface side of the flat cylindrical electrode body 2. Specifically, the protective plate 7 is disposed at a position where the divided non-covered laminated portion 271 is sandwiched between the protective plate 7 and the joint piece 522.

  The protective plate 7 of the present embodiment is a plate-like member, and has a substantially rectangular shape elongated in the Z-axis direction. The protective plate 7 is in contact with the divided non-covered laminated portion 271 and extends from the first portion 71 to the coated laminated portion 26 side of the first portion 71 extending in the X-axis direction. And a second portion 72 excluding both ends (see FIGS. 4 and 5). The protective plate 7 also has a third portion 73 which is a portion on both sides of the first portion 71 and the second portion 72 in the Z-axis direction (see FIG. 6).

  The boundary portion β of the protection plate 7 (the boundary portion β between the first portion 71 and the second portion 72) overlaps the boundary portion α between the first surface 291 and the second surface 292 and, for example, has a curved shape (See Figure 5). Furthermore, protective plate 7 is a current collector in the Y-axis direction in the region including boundary portion α in first surface 291 and second surface 292 by bonding (for example, ultrasonic bonding) of electrode body 2 and current collector 5. Press the body 5 side. In the protective plate 7 having the above configuration, the first portion 71 is disposed at the center in the Z-axis direction at both ends of the electrode body 2 in the X-axis direction (the outer side in the non-covering laminated portion 27) The third portion 73 is disposed. Further, on the inner side in the X-axis direction of the electrode body 2 (inner side in the non-coated laminated portion 27), the second portion 72 is arranged at the center in the Z-axis direction and the third portions 73 are arranged on both sides in the Z-axis direction (See Figure 6).

  The first portion 71 extends along the first surface 291 of the electrode body 2 in the same direction as the first surface 291 (for example, in the X-axis direction). The end 710 extending from the first portion 71 means that the end 710 extends from the first portion 71 in a cross section in the XY plane (see FIGS. 4 and 5). In addition, the first portion 71 is connected to the electrode body 2 by ultrasonic bonding, for example, so that the end portion 290 of the electrode body 2 is compared with other portions such as the second portion 72 and the third portion 73. It is low in contrast (see FIGS. 4 to 6). The first portion 71 of the present embodiment is in surface contact with the first surface 291 of the electrode body 2. A portion of the surface of the first portion 71 in contact with the first surface 291 excluding the bonding portion has, for example, a smooth shape similar to the first surface 291. Furthermore, the length of the first portion 71 in the X-axis direction is determined by the length in the X-axis direction of the bending portion of the protective plate 7 (the length of the second portion 72 in the X-axis direction). The length in the Z-axis direction of the first portion 71 is determined by the length in the X-axis direction of the bonding portion (for example, bonding portion by ultrasonic bonding) between the electrode body 2 and the current collector 5. Further, the outer edge of the first portion 71 in the X-axis direction overlaps the outer edge of the first surface 291 in the X-axis direction. Furthermore, the thickness of the first portion 71 in the Y-axis direction is substantially uniform at each position in the XZ plane direction of the first portion 71.

  The second portion 72 of this embodiment is bent relative to the first portion 71 in the direction away from the current collector 5. In other words, the second portion 72 extends from the tip of the first portion 71 and a portion of the end portion 710 excluding both end portions in the Z-axis direction is bent to the opposite side to the current collector 5 side in the Y-axis direction It is formed by Specifically, the second portion 72 is a portion where the central portion in the Z-axis direction of the end portion 710 in the X-axis direction of the substantially rectangular protection plate 7 elongated in the Z-axis direction is bent ( See Figure 11). Specifically, the second portion 72 is curved in the X-axis direction and also curved in the Z-axis direction. An end edge (start position of bending) 72R of the bending at the second portion 72 has a substantially arc shape (for example, a substantially arc shape with a small curvature) extending in the Z-axis direction. In addition, the part (central part in Z-axis direction) except the both ends in the Z-axis direction of the edge 72R of the bending in the 2nd part 72 is the boundary part (beta). Further, the second portion 72 is farther from the current collector 5 as it is farther from the first portion 71 in the X-axis direction (see FIG. 5). The second portion 72 of the present embodiment is in surface contact with the second surface 292 of the electrode body 2. The surface in contact with the second surface 292 of the second portion 72 has, for example, a smooth shape similar to the second surface 292. Further, an angle θ1 between the surface of the first portion 71 in contact with the electrode body 2 and the surface of the second portion 72 in contact with the electrode body 2 is an angle along the bending of the second surface 292 with respect to the first surface 291 It has become. Specifically, since the angle θ1 is the same as the angle θ2 formed by the first surface 291 and the second surface 292 or an angle smaller than the angle θ2, the electrode plate 2 is less likely to be broken by the protective plate 7 It has become.

  In a state where the second portion 72 is in surface contact with the second surface 292, the first portion 71 is sunk by connection (for example, ultrasonic bonding) between the electrode body 2 and the current collector 5. When the inner portion in the Y-axis direction is pulled toward the inner side in the Y-axis direction when the first portion 71 and the electrode body 2 are joined, the third portion 73 in the present embodiment is in the Z-axis direction. It elastically deforms to incline (see FIG. 6). The third portion 73 is farther from the current collector 5 in the Y-axis direction as it is positioned more outward in the Z-axis direction. The third portion 73 has a second surface 292 (uncoated laminated portion 27) due to elastic recovery force (force that causes the elastically deformed portion to return to the initial position (position before deformation)) generated by elastic deformation. Is pressed to the current collector 5 side in the Y-axis direction. The length in the Z-axis direction of portions of the third portion 73 located on both sides of the first portion 71 is determined by the length in the Z-axis direction of the bonding portion by ultrasonic bonding. The length in the Z-axis direction of portions of the third portion 73 located on both sides of the second portion 72 is the length in the Z-axis direction of the bending portion in the protective plate 7 (the length in the Z-axis direction of the second portion 72 It becomes settled by).

  The third portion 73 includes a corner portion 73R which is included in the end portion 710 and has a curved shape (a shape without corners, hereinafter referred to as “R shape”) (see FIG. 11). The corner portions 73 </ b> R are two corner portions adjacent in the Z-axis direction in the substantially rectangular protection plate 7.

  The surface on which the first portion 71 of the end surface 290 of the electrode body 2 is overlapped is the first surface 291, and the surface on which the second portion 72 of the end surface 290 of the electrode body 2 is overlapped is the second surface 292. The surface on which the third portion 73 of the end surface 290 of 2 is overlapped is the third surface 293.

  The insulating member 6 is disposed between the case 3 (specifically, the case main body 31) and the electrode assembly 2. The insulating member 6 is formed of an insulating resin. The insulating member 6 of the present embodiment is formed in a bag shape by bending a sheet-like member having insulation which is cut into a predetermined shape (see FIG. 2).

  Next, a method of manufacturing the storage element 1 will be described with reference to FIGS.

  First, the external terminal 4 and the current collector 5 are assembled to the lid plate 32. Subsequently, the electrode body 2 is bonded to the current collector 5 in a state of being assembled to the lid plate 32. In the example of the present embodiment, the non-coated laminated portion 27 (specifically, the divided non-coated laminated portion 271) of the electrode body 2 and the bonding piece 522 of the current collector 5 are ultrasonically bonded. Further, in the example of the present embodiment, the ultrasonic bonding is performed in a state in which the electrode body 2 is sandwiched between the protective plate 7 and the current collector 5. In the protective plate 7, the second portion 72 is bent in advance. In addition, the protective plate 7 is bent in advance in a portion overlapping the portion bent by bonding in the electrode body 2 (non-coated laminated portion 27). The details are as follows.

  As shown in FIGS. 7 and 8, the bonding piece 522 of the current collector 5 is in surface contact with the divided non-covered laminated portion 271 from the inner peripheral surface side of the flat cylindrical electrode body 2 in the Y-axis direction. Will be placed. Further, the protective plate 7 is disposed on the outer peripheral surface side of the cylindrical electrode body 2 in the Y-axis direction with respect to the divided non-covered laminated portion 271 (see FIG. 9).

  For example, the protective plate 7 is formed by processing a substantially rectangular plate into two rounded corner portions 73R of four corner portions, and two corners of an end 710 including the two corner portions 73R. It forms by bending the center part pinched | interposed into the part 73R (refer FIG. 10). The protective plate 7 formed in this manner is formed by bending a first portion 71 extending along the X-axis direction and a portion extending from the first portion 71 and excluding both ends in the Z-axis direction. And a site 72 (see FIG. 11). The edge (the bending start position) 72R of the bending at the second portion 72 includes the boundary portion β between the first portion 71 and the second portion 72. The end edge 72R of the bend in the second portion 72 has a substantially arc shape (for example, a substantially arc shape with a small curvature). Further, similarly, the boundary portion β between the first portion 71 and the second portion 72 has a substantially arc shape (for example, a substantially arc shape with a small curvature).

  Further, when the electrode body 2 and the current collector 5 are connected (for example, ultrasonic bonding), the first portion 71 sinks in the Y-axis direction by being sandwiched between a horn 80 and an anvil 81 described later. . Thus, the third portion 73 is a portion located on both sides of the sunk portion of the protective plate 7 in the Z-axis direction and inclined outward in the Y-axis direction. The third portions 73 are located, for example, on both sides of the first portion 71 and the second portion 72 in the Z-axis direction. Note that the third portion 73 before ultrasonic bonding extends along the X-axis direction in the same manner as the first portion 71. The corner 73R located at the end of the third portion 73 in the X-axis direction is R-shaped.

  Thus, when the joining piece 522, the divided non-covered laminated part 271, and the protective plate 7 are stacked so that the divided non-covered laminated part 271 is located between the joined piece 522 and the protective plate 7, FIGS. As shown in FIG. 13, in a state in which the overlapped joint piece 522, the divided non-covered laminated portion 271, and the protective plate 7 are sandwiched by the horn 80 and the anvil 81 and the horn 80 is pressed toward the anvil 81. Ultrasonic bonding is performed by ultrasonic vibration. At this time, since the horn 80 or the anvil 81 does not directly contact the uncoated laminate 27, that is, since the protective plate 7 or the joint piece 522 is present between the horn 80 or the anvil 81 and the uncoated laminate 27, ultrasonic waves are generated. Damage (breakage) of the non-covered portions 231, 241 when vibration is applied is prevented.

  At the time of this joining, the region overlapping the first portion 71 in the non-covered laminated portion 27 is compressed and becomes thinner, and the first portion 71 is closer to the end face 290 of the electrode body 2 than the second portion 72 and the third portion 73. It becomes lower against. In addition, a region overlapping the second portion 72 in the non-covering laminated portion 27 has a shape along the shape of bending in the second portion 72. By such deformation of the non-covering laminated portion 27, a boundary portion α between the first surface 291 and the second surface 292 is formed on the end surface 290 of the electrode body 2 (see FIG. 5).

  In this connection, the third portion 73 is elastically deformed so as to incline in the Y-axis direction, and the elastic recovery force generated by the elastic deformation makes the third surface 293 the current collector 5 side in the Y-axis direction. (See Figure 6).

  The ultrasonic bonding of the joining piece 522, the division non-covering lamination part 271, and the protective plate 7 is repeated or simultaneously performed at a plurality of places, so that the two division non-covering lamination parts on the positive electrode side of the electrode body 2 are performed. (Two split non-covering laminated portions aligned on opposite sides of the hollow portion 28 on the positive electrode side) 271 and two joint pieces 522 of the current collector 5 of the positive electrode are respectively joined, and the two divisions on the negative electrode side of the electrode assembly 2 The non-coated laminated portion 271 and the two bonding pieces 522 of the current collector 5 of the negative electrode are respectively bonded. Thus, the electrode assembly 2 is assembled to the lid plate 32.

  When the electrode body 2, the current collector 5, the external terminal 4 and the like are assembled to the cover plate 32, the cover plate 32 is assembled to the cover plate 32 until the cover plate 32 abuts against the opening peripheral portion 34 of the case main body 31. The electrode body 2 in the state is inserted into the case main body 31. At this time, the periphery of the electrode body 2 is covered by the insulating member 6.

  Subsequently, the boundary between the cover plate 32 and the opening peripheral edge portion 34 of the case main body 31 is welded (laser welding etc.), and thereafter, the electrolytic solution is injected from the injection hole provided in the case 3 (injection). By sealing the liquid injection hole, the storage element 1 is completed.

  According to the storage element 1 described above, the bending boundary of the electrode body 2 in the protective plate 7 (a portion that is bent by being held by the curved protective plate 7 of the electrode body 2, the first surface 291 and the second surface The portion covering the boundary portion α) with the surface 292 has a curved shape by being bent, that is, it is not angular than the corners of the protective plate (the bending angle is larger than the corners of the protective plate) Therefore, the pressure from the protective plate 7 is suppressed from being concentrated on the boundary portion α of the electrode body 2, and even if the protective plate 7 presses the uncoated laminated portion 27, the uncoated laminated portion 27 is damaged. It is difficult to do. In addition, since the second portion 72 is bent along the second surface 292, the tip end of the second portion 72 (in the X-axis direction as compared to a configuration in which the protective plate 7 is not bent with respect to the electrode body 2 Since the edge of the second portion 72 located opposite to the one portion 71 can not strongly press the non-covered laminate 27, the damage due to the tip is also suppressed. Therefore, the occurrence of damage to the electrode body 2 by the protective plate 7 can be suppressed.

  Further, in such a configuration, for example, the width of the covering laminated portion 26 in the X-axis direction (the width of the covering portion 232 or the covering portion 242 in the X-axis direction) is increased to make the first surface 291 of the second surface 292 Even if the electrode body 2 is bent so as to increase the angle, the occurrence of damage to the electrode body 2 by the protective plate 7 can be suppressed. Therefore, it is easy to increase the capacity of the storage element 1 by widening the width in the X-axis direction of the covering laminate portion 26 (increasing the active material layer). Furthermore, in such a configuration, for example, by increasing the number of electrodes included in the electrode body 2, even if the electrode body 2 is bent so that the angle of the second surface 292 with respect to the first surface 291 becomes large, the protective plate The occurrence of damage to the electrode assembly 2 due to 7 can be suppressed. Therefore, it is easy to increase the capacity of the storage element 1 by increasing the number of electrodes included in the electrode body 2.

  In the method of manufacturing the storage element 1 of the present embodiment, at the end 710 of the protection plate 7, a portion (third portion 73) which is not bent at both sides (both sides in the Z-axis direction) of the second portion 72 which is bent. Some are provided. Therefore, compared to the configuration in which the entire end 710 is bent, it is possible to prevent the formation of highly rigid corner portions at both ends of the end 710 in the Z-axis direction. Thereby, the protective plate 7 can be superimposed on the electrode body 2 in a state in which the bending at the second portion 72 is held.

  In addition, in the storage element 1 of the present embodiment, the elastic recovery force of the protective plate 7 causes the protective plate 7 to hold around the bonding portion between the electrode body 2 and the current collector 5 to load some load on the electrode body 2 (for example, When vibration or impact occurs, the load applied to the bonding site can be reduced, and the occurrence of damage can be suppressed.

  Furthermore, in the storage element 1 of the present embodiment, since the corner 73R of the end 710 of the protection plate 7 is R-shaped, damage to the electrode body 2 due to the corner 73R is greater than when the corner is angular. Occurrence is further suppressed.

  The storage element of the present invention is not limited to the above embodiment, and it goes without saying that various modifications can be made without departing from the scope of the present invention. For example, the configuration of one embodiment can be added to the configuration of another embodiment, and part of the configuration of one embodiment can be replaced with the configuration of another embodiment. In addition, some of the configuration of an embodiment can be deleted.

  In the protective plate 7 of the above embodiment, the end edge (start position of bending) 72R of the bending at the second portion 72 is substantially arc-shaped (for example, substantially arc-shaped with a small curvature), but is trapezoidal. Or, it may be triangular. The protective plate 7 can be bent using a conventionally known process such as a tool or a drawing process.

  The second portion 72 of the protective plate 7 of the above embodiment is in surface contact with the second surface 292 of the electrode body 2, but at least the protective plate 7 is pressing a region including the boundary portion β, At least a portion of the second portion 72 may not be in surface contact with the second surface 292.

  In the electrode body 2 of the above-described embodiment, the portion excluding the bonding portion of the first surface 291 and the second surface 292 have a smooth shape, but may have an uneven shape. Also in this case, the first surface 291 and the second surface 292 can be shaped along the first portion 71 and the second portion 72 of the protective plate 7.

  Even in such a configuration, the boundary portion β covering the boundary of bending of the electrode body 2 in the protective plate 7 (the boundary portion α between the first surface 291 and the second surface 292) is bent by bending. If it has a shape as described above, the occurrence of damage to the electrode body 2 by the protective plate 7 can be suppressed.

  Although the electrode body 2 of the said embodiment is what is called a wound type with which the elongate electrodes 23 and 24 were wound, it is not limited to this structure. The electrode body 2 may be a so-called laminated type in which sheet-like electrodes 23 and 24 are stacked, or even one in which at least one of the positive electrode 23 or the negative electrode 24 is long and folded (turned to meander) Good.

  In the storage element 1 of the above embodiment, the electrode body 2 and the current collector 5 are joined by ultrasonic bonding, but they may be joined by another method such as resistance welding.

  In the above embodiment, although the case where the storage element is used as a chargeable / dischargeable non-aqueous electrolyte secondary battery (for example, lithium ion secondary battery) has been described, the type and size (capacity) of the storage element are arbitrary. It is. Moreover, in the said embodiment, although the lithium ion secondary battery was demonstrated as an example of an electrical storage element, it is not limited to this. For example, the present invention can be applied to various secondary batteries, as well as storage devices of capacitors such as primary batteries and electric double layer capacitors.

  The storage element (for example, battery) 1 may be used in a storage device (a battery module in the case of the storage element being a battery) 11 as shown in FIG. Power storage device 11 has at least two power storage elements 1 and a bus bar member 12 electrically connecting two (different) power storage elements 1 with each other. In this case, the technique of the present invention may be applied to at least one storage element 1.

  DESCRIPTION OF SYMBOLS 1 ... electrical storage element, 2 ... electrode body, 21 ... core, 22 ... laminated body, 23 ... positive electrode (electrode), 231 ... uncoated portion, 232 ... coated portion, 24 ... negative electrode (electrode), 241 ... uncoated portion , 242: coated portion, 25: separator, 26: coated stacked portion, 27: uncoated stacked portion, 271: divided non-coated stacked portion, 28: hollow portion, 29: end face, 291: first surface, 292: second Surface 3 3 Case 31 Case main body 311 Blockage section 312 Body section 313 Long wall section 314 Short wall section 32 Lid plate 34 Opening peripheral section 4 External terminal 5 Current collector, 51: first connection portion, 52: second connection portion, 521: main body, 522: joint piece, 53: bent portion, 56: opening, 6: insulating member, 7: protective plate, 71: first Portions 710, end portions 72, second portions 72R, edge portions 73, third portions (both end portions) 73R, corner portions Reference Signs List 0: horn 81: anvil 11: power storage device 12: bus bar member 102: wound electrode body 105: current extraction terminal 107: buffer plate 180: horn 181: anvil, α, β: boundary Part, C ... winding center axis

Claims (2)

An electrode including a metal foil and a coated portion having an active material layer overlapping the metal foil and a non-coated portion having a metal foil extended from the metal foil of the coated portion and exposed from the active material layer is laminated in the thickness direction Electrode body, and
A current collector which is stacked in the stacking direction of the electrode with respect to the non-coating laminated portion in which the non-coating portion is laminated;
And a protective plate sandwiching the non-coated laminated portion with the current collector from the opposite side of the current collector in the stacking direction.
The protective plate is
A first portion that abuts on the uncoated laminate portion and extends in the alignment direction of the coated laminate portion on which the coated portion is laminated and the uncoated laminate portion;
A second portion extending from the first portion to the coated laminated portion and excluding both end portions of the protective plate in a direction orthogonal to both the laminating direction and the arranging direction, which is the second portion from the current collector And a second portion that is bent with respect to the first portion in a direction away from the second portion.   The portions on both sides of the first portion and the second portion in the direction orthogonal to both the stacking direction and the arranging direction are surfaces of the non-covered laminated portion due to elastic recovery force generated by elastic deformation. The storage element according to claim 1, wherein the storage element is pressed toward the current collector in the stacking direction.

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