JP2021180125A - Power storage element - Google Patents

Abstract

To provide a power storage element in which damage to an electrode body due to a plate-shaped portion or an edge of a plate-shaped member connected to the electrode body is suppressed.SOLUTION: A power storage element includes a flat electrode body with laminated electrodes, a current collector 5 connected to an end portion of the electrode body in a predetermined direction orthogonal to the thickness direction of the electrode body, and a plate-shaped member that sandwiches the end portion of the electrode body together with the current collector, the thickness B at the end of the electrode body is smaller than the thickness A at the center of the electrode body as viewed from the thickness direction (X), and the plate-shaped member includes a joint portion 70 joined to the end portion of the electrode body, and a first extension portion 71 extending from the joint portion to the central portion side of the electrode body, and the first extension portion extends along the surface of the electrode body in a state of being inclined with respect to the joint portion, and at least the tip is separated from the surface of the electrode body.SELECTED DRAWING: Figure 6

Description

The present invention relates to a power storage element including an electrode body in which electrodes are laminated and a plate-shaped portion or a plate-shaped member bonded to the electrode body.

Conventionally, a secondary battery including a winding electrode group has been known (see Patent Document 1). Specifically, this secondary battery includes a battery container including a can body and a lid. The can body accommodates a group of wound electrodes. The lid plate is provided with an external terminal. The external terminal is electrically connected to the winding electrode group via the current collector. The winding electrode group has a laminated structure by winding a strip-shaped electrode in a flat shape around the winding axis with a separator interposed therebetween. In this winding electrode group, both ends in the winding axis direction are separated into two bundled electrode connecting portions 111 by being pushed outward of the can body 101 as shown in FIG. ..

Further, each of the pair of drawing portions (connection portions with the wound electrode group 110) of the current collector 102 has a cross section L due to the main plate 104 and the rib plate 105 extending in the height direction of the wound electrode group 110. It has a joint plate 103 having a character shape.

At both ends of the winding electrode group 110 in the winding axis direction, the two bundled electrode connecting portions 111 form a bonding plate 103 of the current collector 102 on each surface of the can body 101 on both wide side surfaces 101a. It is connected to the main plate 104 and ultrasonically bonded. At this time, each of the two rib plates 105 is in contact with the laminated portion of the electrodes (turning electrode group 110) from the boundary portion with the main plate 104 to the tip end.

In the above secondary battery 100, when the number of times the electrode is wound in the wound electrode group 110 increases, the surface of the portion along the rib plate 105 with respect to the bundled electrode connecting portion 111 (the portion of the wound electrode group 110). Since the angle of the rib plate 105 becomes steep, the edge (corner portion) of the tip of the rib plate 105 (the tip in the direction away from the main plate 104) easily bites into the portion, and the bite of this edge causes the electrodes constituting the winding electrode group 110 to bite. May be damaged.

Japanese Patent No. 5663415

Therefore, an object of the present embodiment is to provide a power storage element capable of suppressing damage to the electrode body due to a plate-shaped portion connected to the electrode body or an edge of the plate-shaped member.

The power storage element of this embodiment is
A flat electrode body with laminated electrodes,
A current collector connected to an end portion of the electrode body in a predetermined direction orthogonal to the thickness direction of the electrode body, and a current collector.
A plate-shaped member that sandwiches the end portion of the electrode body together with the current collector is provided.
The thickness of the end portion of the electrode body is smaller than the thickness of the central portion of the electrode body as viewed from the thickness direction.
The plate-shaped member has a joint portion joined to the end portion of the electrode body, and a first stretched portion extending from the joint portion toward the central portion side of the electrode body.
The first stretched portion extends along the surface of the electrode body in a state of being inclined with respect to the joint portion, and at least the tip thereof is separated from the surface of the electrode body.

According to this configuration, since the tip of the first stretched portion is separated from the surface of the electrode body, the tip (edge) of the first stretched portion is the electrode body even if vibration or the like is applied to the power storage element or the electrode body. It does not come into contact with the surface, whereby damage to the electrode body due to biting of the edge or the like can be suppressed.

The power storage element is
A case for accommodating the electrode body is provided.
The tip of the first stretched portion may be located inside the edge of the central portion in the thickness direction.

According to this configuration, since the tip of the first stretched portion is located inside the edge of the central portion of the electrode body in the thickness direction, the tip of the first stretched portion and the case or the case and the electrode body are formed. In some cases, the contact with the edge position of the central portion in the thickness direction or another member located outside the edge position is suppressed, and thereby the tip (edge) comes into contact with the other member. Damage to the other members is suppressed.

Further, in the power storage element,
The plate-shaped member has a second stretched portion extending from the joint portion on the side opposite to the first stretched portion side in the predetermined direction.
The second stretched portion extends in a state of being inclined toward the same side as the first stretched portion in the thickness direction with respect to the joint portion.
The tip of the second stretched portion may be located inside the edge of the electrode body when viewed from the thickness direction and inside the tip of the first stretched portion in the thickness direction.

According to such a configuration, it is difficult for the tip of the second stretched portion extending from the joint portion to the edge side of the electrode body to come into contact with the case, whereby the tip (edge) of the second stretched portion comes into contact with the case. Damage is more reliably suppressed.

Further, the power storage element of this embodiment is
With external terminals
A flat electrode body with laminated electrodes,
A current collector having a plate-like portion connected to an end portion of the electrode body in a predetermined direction orthogonal to the thickness direction of the electrode body and conducting the external terminal and the electrode body is provided.
The thickness of the end portion of the electrode body is smaller than the thickness of the central portion of the electrode body as viewed from the thickness direction.
The plate-shaped portion has a joint portion joined to the end portion of the electrode body and a third stretched portion extending from the joint portion toward the central portion side of the electrode body.
The third stretched portion extends along the surface of the electrode body in a state of being inclined with respect to the joint portion, and at least the tip thereof is separated from the surface of the electrode body.

According to this configuration, even if the connection portion of the current collector with the electrode body is a plate-shaped portion (plate-shaped portion), the edge of the portion (tip of the first stretched portion) is separated from the surface of the electrode body. Therefore, when vibration or the like is applied to the power storage element or the electrode body, the tip (edge) of the first stretched portion does not come into contact with the surface of the electrode body, which causes the electrode to bite into the edge. Damage to the body is suppressed.

From the above, according to the present embodiment, it is possible to provide a power storage element in which damage to the electrode body due to a plate-shaped portion or an edge of the plate-shaped member connected to the electrode body is suppressed.

FIG. 1 is a perspective view of a power storage element according to the present embodiment. FIG. 2 is an exploded perspective view of the power storage element. FIG. 3 is a diagram for explaining the configuration of the electrode body included in the power storage element. FIG. 4 is a diagram showing a state in which an external terminal, a current collector, an electrode body, and a plate-shaped member are assembled to a lid plate. FIG. 5 is a cross-sectional view of the VV position in FIG. FIG. 6 is an enlarged view of the position indicated by VI in FIG. FIG. 7 is an enlarged view of a plate-shaped member connected to the electrode body. FIG. 8 is a schematic diagram of a power storage device including the power storage element. FIG. 9 is an enlarged cross-sectional view of a connection portion between a winding electrode group and a current collector in a conventional secondary battery.

Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 7. The power storage element includes a primary battery, a secondary battery, a capacitor and the like. In this embodiment, a rechargeable secondary battery will be described as an example of the power storage element. The names of the constituent members (each constituent element) of the present embodiment are those in the present embodiment, and may be different from the names of the respective constituent members (each constituent element) in the background art.

The power storage element of this embodiment is a non-aqueous electrolyte secondary battery. More specifically, the power storage element is a lithium ion secondary battery that utilizes electron transfer generated by the movement of lithium ions. This type of power storage element supplies electrical energy. The power storage element may be used alone or in a plurality. Specifically, the power storage element is used alone 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 power storage element is used in the power storage device in combination with another power storage element. In the power storage device, the power storage element used in the power storage device supplies electric energy.

As shown in FIGS. 1 to 3, the current collecting element includes an external terminal 4, a flat electrode body 2 in which an electrode 22 is laminated, a current collector 5 for conducting the electrode body and the external terminal, and a current collector. A plate-shaped member 7 that sandwiches the electrode body 2 together with the 5 is provided. Further, the power storage element 1 includes a case 3 in which the electrode body 2 is housed and an external terminal 4 is arranged, and an insulating member 6 extending along the inner surface of the case 3 between the electrode body 2 and the case 3. Be prepared. The plate-shaped member 7 shown in FIG. 2 is in a state (shape) before being connected to the electrode body 2 (ultrasonic bonding in the example of the present embodiment).

The electrode body 2 is a so-called winding type electrode body in which the electrode 22 is wound flat. Specifically, the electrode body 2 has a winding core 20 and a laminated body 21 composed of an electrode 22 wound around the winding core 20 and a separator 25. The electrode 22 of the present embodiment includes a positive electrode 23 and a negative electrode 24. In the following, the thickness direction of the electrode body 2 is defined as the X-axis direction of the Cartesian coordinate system, and the extending direction (predetermined direction) of the winding axis C of the electrode body 2 is defined as the Y-axis direction of the Cartesian coordinate system. And the direction orthogonal to each of the Y-axis direction is defined as the Z-axis direction of the Cartesian coordinate system.

In the laminated body 21, the positive electrode 23 and the negative electrode 24 are laminated in a state of being insulated from each other. Lithium ions move between the positive electrode 23 and the negative electrode 24 in the electrode body 2, so that the power storage element 1 is charged and discharged.

The positive electrode 23 has a band-shaped metal foil 231 and a positive electrode active material layer 232 superimposed on the metal foil 231. The positive electrode active material layer 232 is superposed on the metal foil 231 in a state where one edge portion (uncovered portion) in the width direction of the metal foil 231 is exposed. The metal foil 231 of the present embodiment is, for example, an aluminum foil.

The negative electrode 24 has a band-shaped metal foil 241 and a negative electrode active material layer 242 superimposed on the metal foil 241. The negative electrode active material layer 242 is formed in a state where the other edge portion (uncovered portion) of the metal foil 241 in the width direction (opposite to the uncoated portion of the metal foil 231 of the positive electrode 23) is exposed. It is overlaid on 241. The metal foil 241 of the present embodiment is, for example, a copper foil.

In the electrode body 2 of the present embodiment, the positive electrode 23 and the negative electrode 24 are wound in a state of being insulated by the separator 25. That is, in the laminated body 21 of the present embodiment, the positive electrode 23, the negative electrode 24, and the separator 25 are laminated.

The separator 25 is an insulating member and is arranged between the positive electrode 23 and the negative electrode 24. As a result, in the electrode body 2 (specifically, the laminated body 21), the positive electrode 23 and the negative electrode 24 are insulated from each other. Further, the separator 25 holds the electrolytic solution in the case 3. As a result, when the power storage element 1 is charged and discharged, lithium ions can move between the positive electrode 23 and the negative electrode 24, which are alternately laminated with the separator 25 interposed therebetween.

The separator 25 is strip-shaped and is composed of, for example, a porous membrane such as polyethylene, polypropylene, cellulose, or polyamide. The separator 25 of the present embodiment has a base material formed of a porous membrane and an inorganic layer provided on the base material. This inorganic layer _{contains inorganic particles such as SiO 2} particles, Al ₂ O ₃ particles, and boehmite (alumina hydrate). Further, the base material is formed of, for example, polyethylene.

The widthwise dimension of the separator 25 is larger than the width of the negative electrode active material layer 242. The separator 25 is arranged between the positive electrode 23 and the negative electrode 24 in which the positive electrode active material layer 232 and the negative electrode active material layer 242 are overlapped with each other in a state of being displaced in the width direction so as to overlap in the thickness direction (stacking direction). NS. At this time, the uncoated portion of the positive electrode 23 and the uncoated portion of the negative electrode 24 do not overlap. That is, the uncoated portion 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 uncoated portion of the negative electrode 24 is the positive electrode 23 and the negative electrode 24. It protrudes from the overlapping region in the width direction (the direction opposite to the protruding direction of the uncovered portion of the positive electrode 23). The electrode body 2 is formed by winding the positive electrode 23, the negative electrode 24, and the separator 25 around the winding core 20 so as to be in such a laminated state (relative position). Further, in the electrode body 2 of the present embodiment, the uncoated laminated portion 26 in the electrode body 2 is configured by the portion where only the uncoated portion of the positive electrode 23 or the uncoated portion of the negative electrode 24 is laminated.

The uncoated laminated portion 26 is provided at each pole of the electrode body 2. That is, the uncoated laminated portion 26 in which only the uncoated portion of the positive electrode 23 is laminated constitutes the uncoated laminated portion of the positive electrode in the electrode body 2, and the uncoated laminated portion 26 in which only the uncoated portion of the negative electrode 24 is laminated is formed. It constitutes an uncoated laminated portion of the negative electrode in the electrode body 2. These two uncoated laminated portions 26 (specifically, the uncoated laminated portion 26 of the positive electrode and the uncoated laminated portion 26 of the negative electrode) are formed at both ends in the winding axis C direction in the electrode body 2, respectively. .. That is, the two uncoated laminated portions 26 constitute each end portion of the electrode body 2 in the winding axis C direction.

As shown in FIGS. 4 and 5, the uncoated laminated portion 26 is connected to the current collector 5 in a conductive state by being sandwiched between the current collector 5 and the plate-shaped member 7. In the power storage element 1 of the present embodiment, the electrode body 2, the current collector 5, and the plate-shaped member 7 are connected by ultrasonic bonding. Due to the sandwiching between the current collector 5 and the plate-shaped member 7, the thickness (dimension in the X-axis direction) of the uncoated laminated portion (end portion of the electrode body 2) 26 is the same as that of the electrode body 2 seen from the X-axis direction. It is smaller than the thickness of the central portion 27 in the Y-axis direction. As a result, the thickness of the portion of the uncoated laminated portion 26 on the central portion 27 side gradually increases toward the central side of the electrode body 2 in the Y-axis direction. In the electrode body 2 of the present embodiment, the central portion is a portion having the largest thickness in the electrode body 2, and is a portion in which the active material layers 232 and 242 of the electrodes 23 and 24 are arranged.

The case 3 houses the electrolytic solution together with the electrode body 2. Specifically, the case 3 has a case main body 31 having an opening and a lid plate 32 that closes (closes) the opening of the case main body 31. The case 3 is formed of a metal that is resistant to the electrolytic solution. Case 3 of the present embodiment is formed of, for example, aluminum or an aluminum-based metal such as an aluminum alloy.

The electrolytic solution is a non-aqueous electrolyte solution. The electrolytic solution is obtained by dissolving an electrolyte salt in an organic solvent. The organic solvent is, for example, cyclic carbonates such as propylene carbonate and ethylene carbonate, and chain carbonates such as dimethyl carbonate, diethyl carbonate, and ethylmethyl carbonate. Electrolyte salts are LiClO ₄ , LiBF _{4 , LiPF 6} , and the like. _{The electrolytic solution of the present embodiment contains 1 mol / L LiPF 6} in a mixed solvent prepared by adjusting ethylene carbonate, dimethyl carbonate, and ethyl methyl carbonate in a ratio of ethylene carbonate: dimethyl carbonate: ethyl methyl carbonate = 3: 2: 5. Is dissolved.

The case body 31 includes a plate-shaped closing portion 311 and a cylindrical body 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 arranged with the opening facing upward (that is, becomes the bottom wall of the case body 31 when the opening faces upward). ) It is a part. 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 at the peripheral edge of the closed portion 311 and a pair of short wall portions 314 extending from the short side at the peripheral edge of the closed portion 311. That is, the pair of long wall portions 313 face each other with an interval in the Y-axis direction (specifically, the interval corresponding to the short side at the peripheral edge of the closed portion 311), and the pair of short wall portions 314 are spaced in the X-axis direction. (Specifically, they face each other with an interval corresponding to the long side at the peripheral edge of the closed portion 311). A square cylindrical body portion 312 is formed by connecting the end portions of the short wall portion 314 corresponding to each other (specifically, facing in the Y-axis direction) of the pair of long wall portions 313.

As described above, the case body 31 has a square tube shape (that is, a bottomed square tube shape) in which one end in the opening direction (Z-axis direction) is closed.

The lid plate 32 is a plate-shaped member that closes the opening of the case body 31. The lid plate 32 of the present embodiment is a rectangular plate material long in the X-axis direction when viewed from the Z-axis direction. In the lid plate 32, the peripheral edge portion of the lid plate 32 is overlapped with the opening peripheral edge portion 34 of the case main body 31 so as to close the opening of the case main body 31.

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

Specifically, the external terminal 4 includes a terminal body 41 having a surface 41A to which a bus bar or the like can be welded, and a penetrating portion penetrating the case 3.

The terminal body 41 is a plate-shaped portion that extends along the lid plate 32. The terminal body 41 of the present embodiment has a rectangular shape when viewed from the Z-axis direction.

The penetrating portion conducts the current collector 5 arranged inside the case 3 and the terminal body 41 arranged outside the case 3. The penetrating portion of the present embodiment is made of a conductive metal and is integrally formed with the terminal body 41. This penetrating portion penetrates the lid plate 32 from the terminal main body 41 and extends into the case 3. Specifically, the penetrating portion extends from the terminal body 41 into the case 3, and together with the terminal body 41, sandwiches the lid plate 32, the current collector 5, and the like in the Z-axis direction. As a result, the external terminal 4 and the current collector 5 are fixed to the lid plate 32, and the external terminal 4 and the current collector 5 are electrically connected to each other.

The current collector 5 is arranged in the case 3 and is directly or indirectly connected to the electrode body 2 so as to be conductive. The current collector 5 is connected to each of the uncoated laminated portion 26 of the positive electrode of the electrode body 2 and the uncoated laminated portion 26 of the negative electrode. That is, the power storage element 1 includes two current collectors 5. The current collector 5 of the present embodiment is connected to an end portion of the electrode body 2 in a predetermined direction (Y-axis direction in the example of the present embodiment) orthogonal to the thickness direction (X-axis direction) of the electrode body 2. (See FIGS. 4 and 5). More specifically, each current collector 5 is connected to the electrode body 2 (specifically, the uncoated laminated portion 26) in a state of sandwiching the uncoated laminated portion 26 of the electrode body 2 together with the plate-shaped member 7.

The current collector 5 is formed of a conductive member. As a result, the current collector 5 connects the penetrating portion of the external terminal 4 and the uncoated laminated portion 26 of the electrode body 2 so as to be conductive. The current collector 5 is arranged along the inner surface of the case 3.

Specifically, the current collector 5 has a first connection portion 51 that is electrically connected to the penetrating portion of the external terminal 4, and a second connection portion that extends from the first connection portion 51 and is conductively connected to the electrode body 2. It has a connecting portion 52 and. In the current collector 5, the first connection portion 51 extends from the penetrating portion of the external terminal 4 toward the short wall portion 314 along the lid plate 32, and the second connection portion 52 extends from the short wall of the first connection portion 51. It extends from the end on the side of the portion 314 toward the closed portion 311 along the long wall portion 313.

The first connection portion 51 is a rectangular plate-shaped portion. Further, the second connecting portion 52 is a strip-shaped portion, and has a base portion 521 extending in the Z-axis direction along the long wall portion 313, and an inclined portion 522 extending in the inclined direction from the base portion 521 with respect to the base portion 521. It has a current collector joint portion 523 extending from the inclined portion 522 in the Z-axis direction. The current collector bonding portion 523 of the present embodiment is a rectangular plate-shaped portion, and is connected so as to be in surface contact with one surface of the uncoated laminated portion 26 in the X-axis direction (in the example of the present embodiment, ultrasonic waves). It is joined).

The current collector 5 configured as described above is formed by bending a plate-shaped metal material cut into a predetermined shape.

The plate-shaped member 7 is arranged in the uncoated laminated portion 26 of the positive electrode and the uncoated laminated portion 26 of the negative electrode, respectively. That is, the power storage element 1 includes two plate-shaped members 7. In the state before joining to the electrode body 2, each plate-shaped member 7 has a rectangular plate shape (see FIG. 2), and the thickness of the plate-shaped member 7 of the present embodiment is, for example, 0.2 mm. .. As shown in FIGS. 4 to 7, the plate-shaped member 7 is formed from the plate-shaped member joint portion (joint portion) 70 joined to the uncoated laminated portion 26 of the electrode body 2 and the plate-shaped member joint portion 70. It has a first stretched portion 71 extending toward the central portion 27 side of the electrode body 2. Further, the plate-shaped member 7 has a second stretched portion 72 extending from the plate-shaped member joint portion 70 to the side opposite to the first stretched portion 71 side in the Y-axis direction.

The plate-shaped member joint portion 70 is a portion of the plate-shaped member 7 that is joined to the uncoated laminated portion 26. The plate-shaped member joint portion 70 of the present embodiment is a rectangular portion (region) elongated in the Z-axis direction joined to the uncoated laminated portion 26 by ultrasonic bonding. The plate-shaped member joint 70 is formed at a position shifted outward from the central portion in the Y-axis direction (end edge side in the Y-axis direction of the electrode body 2) in the plate-shaped member 7.

The first stretched portion 71 extends along the surface of the electrode body 2 in an inclined state with respect to the plate-shaped member joint portion 70, and at least the tip end 71a is separated from the surface of the electrode body 2. The tip 71a of the first stretched portion 71 is on the plate-shaped member joint portion 70 side (lower side in FIG. 6) in the X-axis direction from the virtual surface V which is in contact with the central portion 27 of the electrode body 2 and is orthogonal to the X-axis direction. positioned. That is, the tip of the first stretched portion 71 is located inside the edge of the central portion 27 in the X-axis direction.

The second stretched portion 72 extends in a state of being inclined toward the same side as the first stretched portion 71 in the X-axis direction with respect to the plate-shaped member joint portion 70. The tip 72a of the second stretched portion 72 is located inside the edge of the electrode body 2 in the Y-axis direction when viewed from the X-axis direction, and a plate-shaped member is joined from the tip 71a of the first stretched portion 71 in the X-axis direction. It is located on the side (inside) of the portion 70 (see FIG. 6).

At the ends of the electrode body 2 in the state where the plate-shaped member 7 and the current collector 5 are joined as described above in the Y-axis direction, the configurations 26, 5 and 7 satisfy the following relationships.

In the power storage element 1 of the present embodiment, the thickness (dimension in the X-axis direction) of the central portion 27 in the Y-axis direction of the electrode body is set to A, and the current collector 5 and the plate-shaped member 7 in the uncoated laminated portion 26 are used. When the thickness of the sandwiched portion is B and the thickness of the plate-shaped member 7 is C, in the power storage element 1 of the present embodiment, B> C and 0.05 ≦ ((B + C) / A). ) ≤ 0.09.

Further, the power storage element 1 of the present embodiment has a first stretched portion 71 with respect to the plate-shaped member joint portion 70 in a cross section on an XY plane (a plane including the X-axis direction and the Y-axis direction: see FIG. 6). The angle θ is the Y-axis direction of the uncoated laminated portion 26, where D is the dimension in the Y-axis direction from the end edge in the Y-axis direction of the electrode body to the end edge on the first stretched portion 71 side of the plate-shaped member joint portion 70. When the dimension of is E, the relationship of tan θ = (A / 2) / (ED) and 1.2 <tan θ <2.65 is satisfied.

Further, in the power storage element 1 of the present embodiment, where X is the distance between the tip 71a of the first stretched portion 71 and the edge of the plate-shaped member joint 70 on the first stretched portion 71 side in the Y-axis direction, X / The relationship of C> 5 is satisfied.

Returning to FIG. 2, the insulating member 6 is arranged between the case 3 (specifically, the case body 31) and the electrode body 2. The insulating member 6 is formed in a bag shape by bending a sheet-shaped member having an insulating property cut into a predetermined shape. The bag-shaped insulating member 6 is arranged between the electrode body 2 and the case 3 in a state of covering the surface of the electrode body 2 together with the current collector 5 and the plate-shaped member 7 joined to the electrode body 2. NS.

The power storage element 1 configured as described above is manufactured as follows.

The electrode body 2 is connected to the current collector 5 assembled to the lid plate 32 together with the external terminal 4. In the method of manufacturing the power storage element 1 of the present embodiment, the current collector 5 and the electrode body 2 are connected by ultrasonic bonding. Specifically, it is as follows.

The current collector joint portion 523 of the current collector 5 and the flat plate-shaped member 7 are arranged on both sides of the uncoated laminated portion 26 of the electrode body 2 in the thickness direction (X-axis direction). In this state, the superposed current collector bonding portion 523, the uncoated laminated portion 26, and the plate-shaped member 7 are sandwiched between the horn and the anvil of the ultrasonic bonding device, and ultrasonic bonding is performed.

At this time, the contact portion of the plate-shaped member 7 with the horn is a position shifted from the central portion in the Y-axis direction to the outside of the uncoated laminated portion 26 (end edge side of the electrode body 2). Then, the horn ultrasonically vibrates in a state where the laminated plate-shaped member 7, the uncoated laminated portion 26, and the current collector joint portion 523 are pressed toward the anvil. As a result, the plate-shaped member joint portion 70 (the contact portion of the horn in the plate-shaped member 7) sinks inward in the thickness direction (stacking direction of the electrodes 22) of the uncoated laminated portion 26, and the first stretched portion 71 and the first stretched portion 71 and The plate-shaped member 7 is deformed so that the second stretched portion 72 is inclined with respect to the plate-shaped member joining portion 70, and the current collector 5, the electrode body 2, and the plate-shaped member 7 are ultrasonically bonded. When the first stretched portion 71 is inclined with respect to the plate-shaped member joint portion 70, at least the tip 71a of the first stretched portion 71 is in a state of being separated from the surface of the electrode body 2 (see FIG. 6).

Next, the electrode body 2 assembled to the lid plate 32 is housed in the bag-shaped insulating member 6, whereby the current collector 5 (specifically, the second connection portion 52) and the current collector 5 bonded to the electrode body 2 and The surface of the electrode body 2 is covered with the insulating member 6 together with the plate-shaped member 7.

Subsequently, the electrode body 2 assembled to the lid plate 32 and whose surface is covered with the insulating member 6 is inserted into the case body 31. When the electrode body 2 is inserted into the case body 31 until the lid plate 32 overlaps (contacts) the opening peripheral edge portion 34 of the case body 31, in this state, the peripheral edge portion of the lid plate 32 and the opening of the case body 31 are opened. The peripheral edge portion 34 is welded, and the boundary portion between the lid plate 32 and the case body 31 is sealed. Welding of the lid plate 32 and the case body 31 of the present embodiment is performed by laser welding.

After the case body 31 and the lid plate 32 are welded together, the electrolytic solution is injected into the case 3 to complete the power storage element 1.

According to the above power storage element, since the tip 71a of the first stretched portion 71 is separated from the surface of the electrode body 2 (see FIG. 6), even if vibration or the like is applied to the power storage element 1 or the electrode body 2, the first The tip 71a (particularly, the edge) of the stretched portion 71 does not come into contact with the surface of the electrode body 2, thereby suppressing damage to the electrode body 2 due to biting of the edge or the like.

Further, in the power storage element 1 of the present embodiment, the tip 71a of the first stretched portion 71 is in contact with the central portion of the electrode body 2 (the thickest portion in the electrode body 2) and is a virtual surface orthogonal to the X-axis direction. It is located on the plate-shaped member joint 70 side in the X-axis direction from V. That is, the tip 71a of the first stretched portion 71 is located inside the edge of the central portion 27 in the X-axis direction (see FIG. 6). As described above, since the tip 71a of the first stretched portion 71 is located on the plate-shaped member joint 70 side in the X-axis direction from the central portion 27 (virtual surface V) of the electrode body 2, the tip 71a and the tip 71a are Contact with the case 3 or another member (insulating member 6 in the example of the present embodiment) located at the edge position of the central portion 27 in the X-axis direction or outside the case 3 between the case 3 and the electrode body 2. This suppresses damage to the case 3 and other members (insulating member 6) due to contact with the tip 71a (edge).

Further, in the power storage element 1 of the present embodiment, the tip 72a of the second stretched portion 72 has a plate shape inside the edge of the electrode body 2 in the Y-axis direction and from the tip 71a of the first stretched portion 71 in the X-axis direction. It is located on the member joint 70 side (inside). Therefore, the tip 72a of the second stretched portion 72 extending from the plate-shaped member joint 70 to the end edge side of the electrode body 2 is less likely to come into contact with the case 3, whereby the tip 72a (edge) of the second stretched portion 72. Damage to the case 3 due to contact with the case 3 is more reliably suppressed.

It should be noted that the power storage element of the present invention is not limited to the above embodiment, and it is needless to say that various modifications can be made without departing from the gist of the present invention. For example, the configuration of one embodiment can be added to the configuration of another embodiment, and a part of the configuration of one embodiment can be replaced with the configuration of another embodiment. In addition, some of the configurations of certain embodiments can be deleted.

In the power storage element 1 of the above embodiment, the plate-shaped member 7 has a first stretched portion 71 and a second stretched portion 72, but the configuration is not limited to this. The plate-shaped member 7 may have at least the first stretched portion 71 of the first stretched portion 71 and the second stretched portion 72.

Further, in the power storage element 1 of the above embodiment, the tip 71a of the first stretched portion 71 is in contact with the central portion 27 of the electrode body 2 (the thickest portion in the electrode body 2) 27 and is orthogonal to the X-axis direction. It is located on the plate-shaped member joint 70 side in the X-axis direction from the surface V, but is not limited to this configuration. As long as at least the tip 71a of the first stretched portion 71 is separated from the surface of the electrode body 2, the tip 71a may not be located on the plate-shaped member joint 70 side in the X-axis direction from the virtual surface V.

Further, in the power storage element 1 of the above embodiment, the tip 72a of the second stretched portion 72 has a plate shape inside the edge of the electrode body 2 in the Y-axis direction and from the tip 71a of the first stretched portion 71 in the X-axis direction. Although it is located on the member joint 70 side, it is not limited to this configuration. The tip 72a of the second stretched portion 72 may be located outside the edge of the electrode body 2 in the Y-axis direction, and is separated from the plate-shaped member joint 70 by the tip 71a of the first stretched portion 71 in the X-axis direction. It may be configured to be located on the side.

Further, in the power storage element 1 of the above embodiment, the plate-shaped member 7 has the first stretched portion 71 and the second stretched portion 72, and is joined to the current collector joint portion (uncoated laminated portion 26) of the current collector 5. The plate-shaped portion) 523 has a flat plate shape, but is not limited to this configuration. The current collector joint portion (joint portion with the uncoated laminated portion 26) 523 of the current collector 5 corresponds to the plate-shaped member joint portion 70 of the plate-shaped member 7 and the portion corresponding to the first stretched portion 71. And may have. Further, the current collector joint portion 523 corresponds to a portion corresponding to the plate-shaped member joint portion 70 of the plate-shaped member 7, a portion corresponding to the first stretched portion 71, and a portion corresponding to the second stretched portion 72. You may also have.

Even with this configuration, the portion corresponding to the tip 71a of the first stretching portion 71 is separated from the surface of the electrode body 2, so that the first stretching is performed when vibration or the like is applied to the power storage element 1 or the electrode body 2. The portion corresponding to the tip 71a of the portion 71 does not come into contact with the surface of the electrode body 2, whereby damage to the electrode 22 constituting the electrode body 2 is suppressed.

Further, in the above embodiment, the case where the power storage element is used as a chargeable / dischargeable non-aqueous electrolyte secondary battery (for example, a lithium ion secondary battery) has been described, but the type and size (capacity) of the power storage element are arbitrary. Is. Further, in the above embodiment, the lithium ion secondary battery has been described as an example of the power storage element, but the present invention is not limited thereto. For example, the present invention can be applied to various secondary batteries, other primary batteries, and storage elements of capacitors such as electric double layer capacitors.

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

1 ... power storage element, 2 ... electrode body, 20 ... winding core, 21 ... laminated body, 22 ... electrode, 23 ... positive electrode (electrode), 231 ... metal foil, 232 ... positive electrode active material layer (active material layer), 24 ... Negative electrode (electrode), 241 ... Metal foil, 242 ... Negative electrode active material layer (active material layer), 25 ... Separator, 26 ... Uncoated laminated part, 27 ... Central part, 3 ... Case, 31 ... Case body, 311 ... Closure Part, 312 ... Body part, 313 ... Long wall part, 314 ... Short wall part, 32 ... Lid plate, 34 ... Opening peripheral part, 4 ... External terminal, 41 ... Terminal body, 41A ... Surface, 5 ... Current collector, 51 ... First connection portion, 52 ... Second connection portion, 521 ... Base portion, 522 ... Inclined portion, 523 ... Current collector joint portion, 6 ... Insulation member, 7 ... Plate-like member, 70 ... Plate-like member joint portion (joint) Part), 71 ... First stretched part, 71a ... Tip, 72 ... Second stretched part, 72a ... Tip, 11 ... Power storage device, 12 ... Bus bar member, 100 ... Secondary battery, 101 ... Can body, 101a ... Both wide Surface, 102 ... Current collector, 103 ... Joint plate, 104 ... Main plate, 105 ... Rib plate, 110 ... Winding electrode group, 111 ... Bundled electrode connection, C ... Winding shaft, V ... Virtual surface

Claims (4)

A flat electrode body with laminated electrodes,
A current collector connected to an end portion of the electrode body in a predetermined direction orthogonal to the thickness direction of the electrode body, and a current collector.
A plate-shaped member that sandwiches the end portion of the electrode body together with the current collector is provided.
The thickness of the end portion of the electrode body is smaller than the thickness of the central portion of the electrode body as viewed from the thickness direction.
The plate-shaped member has a joint portion joined to the end portion of the electrode body, and a first stretched portion extending from the joint portion toward the central portion side of the electrode body.
The first stretched portion is a power storage element that extends along the surface of the electrode body in a state of being inclined with respect to the joint portion, and at least the tip thereof is separated from the surface of the electrode body. A case for accommodating the electrode body is provided.
The power storage element according to claim 1, wherein the tip of the first stretched portion is located inside the edge of the central portion in the thickness direction. The plate-shaped member has a second stretched portion extending from the joint portion on the side opposite to the first stretched portion side in the predetermined direction.
The second stretched portion extends in a state of being inclined toward the same side as the first stretched portion in the thickness direction with respect to the joint portion.
The second aspect of claim 2, wherein the tip of the second stretched portion is located inside the edge of the electrode body when viewed from the thickness direction and inside the tip of the first stretched portion in the thickness direction. Power storage element. With external terminals
A flat electrode body with laminated electrodes,
A current collector having a plate-like portion connected to an end portion of the electrode body in a predetermined direction orthogonal to the thickness direction of the electrode body and conducting the external terminal and the electrode body is provided.
The thickness of the end portion of the electrode body is smaller than the thickness of the central portion of the electrode body as viewed from the thickness direction.
The plate-shaped portion has a joint portion joined to the end portion of the electrode body and a third stretched portion extending from the joint portion toward the central portion side of the electrode body.
The third stretched portion is a power storage element that extends along the surface of the electrode body in a state of being inclined with respect to the joint portion, and at least the tip thereof is separated from the surface of the electrode body.

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