JP2014165051A - Power storage device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power storage device in which movement of an electrode assembly to an electrode side can be suppressed.SOLUTION: In a secondary battery 1, a bag-shaped insulating film 40 having a lower surface coating 41 covering a lower surface 23 and a side peripheral surface coating 42 covering a side peripheral surface 21 is fixed to an electrode assembly 20, and the insulating film 40 and a lower surface 11b of a case 10 are fixed by a fixing part 50 such as a double-side tape. More specifically, the electrode assembly 20 is fixed to the case 10 while interposing the insulating film 40. With such an arrangement, movement of the electrode assembly 20 to an electrode 30 side can be suppressed, even when the secondary battery 1 is turned up side down.

Description

  The present invention relates to a power storage device.

  Conventionally, as a secondary battery which is a kind of power storage device, for example, a lithium ion secondary battery or a nickel-hydrogen secondary battery is well known. Such a secondary battery has a configuration in which an electrode assembly which is a power storage element is accommodated in a case. In the electrode assembly, an electrode obtained by coating an active material on a metal foil such as an aluminum foil is layered. Further, the secondary battery includes a pair of electrode terminals for taking out electric power to the outside, the positive electrode of the electrode assembly is connected to the positive electrode terminal via a conductive member, and the negative electrode of the electrode assembly is electrically connected to the negative electrode terminal. They are connected via members (hereinafter, conductive portions including electrode terminals and conductive members for taking out electric power to the outside may be collectively referred to as “electrode portions”). In such secondary batteries, a conductive case is often used as the case, and in that case, an insulating cover is provided between the electrode assembly and the case in order to avoid a short circuit between the electrode assembly and the case. May be provided.

  For example, Patent Document 1 below discloses a secondary battery in which an insulating cover made of a sheet-like resin material is provided between an electrode assembly and a case. The case of the secondary battery includes a rectangular parallelepiped battery can having an upper opening, and a battery lid that closes the upper opening of the battery can and is provided with an electrode portion, and an electrode assembly is provided in the case. Contained.

JP 2011-198663 A JP-A-1-239769 JP 2011-155001 A JP-A-11-204095 JP-A-57-57471 JP-A-1-204370

  However, the conventional secondary battery described above has the following problems. That is, in a normal arrangement, the electrode part provided on the battery lid that closes the upper opening and the electrode assembly are insulated from each other in the vertical direction, but the battery can is turned upside down and the electrode assembly is arranged. When the battery lid is positioned below the three-dimensional object, the electrode assembly may move to the electrode part side, and the electrode assembly and the electrode part may come into contact with each other.

  Such a problem may occur not only in the secondary battery but also in other power storage devices such as an electric double layer capacitor.

  Then, an object of this invention is to provide the electrical storage apparatus which can suppress the movement to the electrode part side of an electrode assembly.

  A power storage device according to the present invention is a power storage device including a case, an electrode assembly housed in the case, and an electrode portion that extracts electric power to the outside. The case includes a cylindrical side peripheral portion, a side The electrode assembly has an upper surface portion positioned on the upper side of the peripheral portion and a lower surface portion positioned on the lower side of the side peripheral portion, and the electrode assembly includes an electrode assembly side peripheral surface facing the side peripheral portion inside the case, An electrode assembly upper surface facing the upper surface portion and an electrode assembly lower surface facing the lower surface portion inside the case, the electrode portion being provided on the upper surface portion of the case, and the power storage device further comprising an electrode assembly An insulating film fixed to the electrode assembly, and a lower surface covering portion and a side peripheral surface of the insulating film having a lower surface covering portion covering the three-dimensional lower surface and a side peripheral surface covering portion covering the electrode assembly side peripheral surface Fix at least one of the cover and the case Comprising a fixed part, a.

  In this power storage device, the lower surface covering portion covering the lower surface of the electrode assembly, and the bag-like insulating film having the side peripheral surface covering portion covering the electrode assembly side peripheral surface are fixed to the electrode assembly, and At least one of the lower surface covering portion and the side peripheral surface covering portion of the insulating film and the case are fixed by the fixing portion. That is, the electrode assembly is fixed to the case with the insulating film interposed. Therefore, even when the power storage device is turned upside down, the electrode assembly can be prevented from moving toward the electrode portion provided on the upper surface portion.

  Moreover, the aspect which fixes a lower surface coating | coated part of an insulating film and the lower surface part of a case may be sufficient as a fixing | fixed part. In this case, the electrode assembly and the case can be fixed while maintaining the heat dissipation from the side peripheral surface of the electrode assembly.

  Moreover, the aspect which is further equipped with the connection part connected to the side peripheral surface coating | coated part of an insulating film while being fixed to an electrode assembly upper surface so that an electrode assembly upper surface may be covered partially may be sufficient. In this case, it can suppress that an electrode assembly slips out of a bag-shaped insulating film by a connection part.

  Further, the electrode assembly may be movable relative to the electrode part inside the case. In the present invention, even if the electrode assembly is movable, the fixing portion suppresses the electrode assembly from moving toward the electrode portion provided on the upper surface portion.

  Further, the power storage device may be a secondary battery.

  ADVANTAGE OF THE INVENTION According to this invention, the electrical storage apparatus which can suppress the movement to the electrode part side of an electrode assembly can be provided.

FIG. 1 is a diagram illustrating an internal configuration of a secondary battery according to an embodiment of the present invention. FIG. 2 is a diagram illustrating an electrode assembly of the secondary battery of FIG. 1 and an insulating film fixed to the electrode assembly. FIG. 3 is a view showing a state in which the case of the secondary battery of FIG. 1 is turned upside down. FIG. 4 is a diagram illustrating a state in which a case is turned upside down in a conventional secondary battery. It is the figure which showed the electrode assembly of the secondary battery which concerns on a modification, and the insulating film fixed to the electrode assembly.

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the accompanying drawings. In addition, the same code | symbol is attached | subjected about the same or equivalent element, and the description is abbreviate | omitted when description overlaps.

  First, the configuration of a secondary battery 1 as a power storage device according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2.

  As shown in FIG. 1, the secondary battery 1 includes a case 10, an electrode assembly 20 accommodated in the case 10, and an electrode unit 30 that extracts electric power to the outside of the secondary battery 1.

  The case 10 is made of, for example, a metal such as stainless steel or aluminum. The case 10 includes a battery can 11 having an upper opening, and an upper surface portion 12 that is a battery lid that closes the upper opening of the battery can 11. The battery can 11 has a rectangular tube-shaped side peripheral portion 11a having a flat inner space, and a lower surface portion 11b that is located below the side peripheral portion 11a and is formed integrally with the side peripheral portion 11a. doing. That is, the upper surface part 12 is located above the side peripheral part 11a, and the lower surface part 11b is located below. The case 10 forms a rectangular parallelepiped sealed space inside.

  In the electrode assembly 20, a sheet-like separator (diaphragm) is sandwiched (interposed), and a rectangular sheet-like positive electrode and negative electrode (electrode sheet) of the same standard are layered (laminated structure). It is a laminated structure having a flattened rectangular parallelepiped outer shape, and stores and supplies electric power by charging. The electrode sheet is obtained by applying an active material to a metal foil, and is disposed in the internal space of the case 10 so that the active material coating surface is perpendicular to the surface inside the case of the lower surface portion 11b.

  When the electrode assembly 20 is housed inside the case, the side peripheral surface 21 (electrode assembly side peripheral surface) facing the side peripheral portion 11a of the case 10 and the upper surface 22 (electrode assembly upper surface) facing the upper surface portion 12 are disposed. ) And a lower surface 23 (an electrode assembly lower surface) facing the lower surface portion 11b. More specifically, the side peripheral surface 21 is a coating surface side peripheral surface 21a that is a coating surface of the outermost electrode sheet among the electrode sheets that constitute the electrode assembly 20, and an end surface side that is configured by an end surface of each electrode sheet. It is comprised from the surrounding surface 21b.

  On the upper end of the electrode sheet, tabs 24 and 25 which are uncoated portions of the active material are provided. The tab 24 is provided at the upper end of the positive electrode sheet, and the tab 25 is provided at the upper end of the negative electrode sheet. The tabs 24 and 25 respectively extend upward from the upper end of the electrode sheet. When viewed from the stacking direction of the electrode sheets, the tabs 24 provided on each positive electrode sheet are arranged at the same position, and the tabs 25 provided on each negative electrode sheet are arranged at the same position. ing. The case 10 is filled with an electrolyte (electrolyte) according to the type of the secondary battery 1 such as a lithium ion secondary battery or a nickel hydride secondary battery.

  The electrode unit 30 includes a pair of electrode terminals (a positive terminal 31 and a negative terminal 32), a conductive member 33 connected to the positive terminal 31, a conductive member 34 connected to the negative terminal 32, and a current interrupt device 35. The electrode assembly 20 is a part for taking out the electric power stored by charging to the outside of the case 10.

  The positive electrode terminal 31 and the negative electrode terminal 32 are columnar conductive members that penetrate the upper surface portion 12 of the case 10, and are attached to the upper surface portion 12 so as to extend along the thickness direction of the upper surface portion 12. . The conductive member 33 is welded to the positive electrode terminal 31 and is welded to the tab 24 of the positive electrode sheet. Similarly, the conductive member 34 is welded to the negative electrode terminal 32 and welded to the tab 25 of the negative electrode sheet. That is, the tab 24 is electrically connected to the positive terminal 31 via the conductive member 33, and the tab 25 is electrically connected to the negative terminal 32 via the conductive member 34.

  The electrical connection between the conductive members 33 and 34 and the tabs 24 and 25 is controlled by a current interrupt device (CID) 35 interposed therebetween. The current interrupt device 35 has a function as a current interrupt valve that interrupts the current path of the secondary battery 1 when the internal pressure of the current becomes higher than a specified value.

  An example of current path interruption by the current interruption device 35 will be described. In order to interrupt the current path by the current interrupt device 35, for example, the conductive member 33 (conductive member 34) is constituted by two conductive plates (first conductive plate and second conductive plate). The first conductive plate is connected to the positive electrode terminal 31 (negative electrode terminal 32), and the second conductive plate is connected to the tab 24 (tab 25). In this state, normally, the first conductive plate and the second conductive plate are connected, and the tab 24 (tab 25) and the positive terminal 31 (negative terminal 32) are electrically connected. Then, when the internal pressure of the secondary battery 1 becomes higher than the specified value, the current interrupt device 35 separates the first conductive plate and the second conductive plate, so that the tab 24 (tab 25). Is interrupted from the current path to the positive terminal 31 (negative terminal 32). Such a current path interrupting method by the current interrupting device 35 is an example, and the current path may be interrupted by other methods.

  As shown in FIG. 1, the secondary battery 1 further includes a bag-like insulating film 40 that covers the periphery of the electrode assembly 20 and is fixed to the electrode assembly 20. The insulating film 40 has an insulating property and is interposed between the electrode assembly 20 and the case 10 to insulate the electrode assembly 20 and the case 10 from each other. The insulating film 40 includes a lower surface covering portion 41 that covers the lower surface 23 and a side peripheral surface covering portion 42 that covers the side peripheral surface 21 in a state where the electrode assembly 20 is included therein. As a constituent material of the insulating film 40, polypropylene (PP), polyphenylene sulfide (PPS), polybutylene terephthalate (PBT), or a composite thereof is used.

  As shown in FIG. 2, the secondary battery 1 further includes an insulating connection tape 60 (connection portion), and the connection tape 60 prevents the electrode assembly 20 from coming out of the insulating film 40. As shown in FIG. 2, the connection tape 60 is connected so as to partially cover the upper surface 22 and span from one side peripheral surface covering portion 42 to the other side peripheral surface covering portion 42 of the insulating film 40. ing. The connection tape 60 may be an adhesive tape, and for example, a Kapton tape excellent in heat resistance, a Teflon (registered trademark) tape, or the like may be used. In the example shown in FIG. 2, the connection by the connection tape 60 is performed at two locations, but it may be performed at one location or three or more locations. In FIG. 2, the tabs 24 and 25 of each electrode sheet constituting the electrode assembly 20 are omitted.

  As shown in FIG. 1, the secondary battery 1 further includes a fixing portion 50 interposed between the lower surface covering portion 41 of the insulating film 40 and the lower surface portion 11 b of the case 10. The fixing portion 50 is a member that fixes the lower surface covering portion 41 and the lower surface portion 11b, and is, for example, a double-sided tape. The double-sided tape that is the fixing portion 50 extends over substantially the entire area of the lower surface covering portion 41. When the fixing portion 50 is a double-sided tape, the electrode assembly 20 covered with the insulating film 40 is accommodated in the case 10 in a state where the double-sided tape is applied in advance to the surface inside the case 10 of the lower surface portion 11b. The lower surface covering portion 41 of the insulating film 40 is fixed to the lower surface portion 11b.

  As described in detail above, in the secondary battery 1 described above, the bag-shaped insulating film 40 having the lower surface covering portion 41 covering the lower surface 23 and the side peripheral surface covering portion 42 covering the side peripheral surface 21 is The lower surface covering portion 41 of the insulating film 40 and the lower surface portion 11b of the case 10 are fixed by a fixing portion 50 such as a double-sided tape. That is, the electrode assembly 20 is fixed to the case 10 with the insulating film 40 interposed.

  Thus, as shown in FIG. 3, even when the secondary battery 1 is turned upside down or is greatly shaken, the electrode assembly 20 is provided on the upper surface portion 12 side. It can suppress moving to.

  On the other hand, as shown in FIG. 4, in the conventional secondary battery 100, when the secondary battery 100 is turned upside down and the upper surface portion 12 is positioned below the electrode assembly 20, 20 may move toward the electrode part 30 provided on the upper surface part 12 and may come into contact with the electrode part 30. At the time of manufacture, the electrode assembly 20 moves and comes into contact with the constituent members, so that the active material applied to the electrode sheet constituting the electrode assembly 20 may be peeled off, resulting in manufacturing defects. Further, even when in use, the electrode assembly 20 and the electrode part 30 may come into contact with each other, which may cause deformation of the electrode assembly 20 or the electrode part 30 or disconnection of the mutual connection.

  In this regard, in the secondary battery 1 according to the present embodiment, it is possible to prevent the electrode assembly 20 from moving to the electrode portion 30 side by the fixing portion 50. Therefore, since contact between the electrode assembly 20 and the component member during the production cannot occur, a production failure due to peeling of the active material applied to the electrode sheet constituting the electrode assembly 20 does not occur. Further, there is no fear of contact between the electrode assembly 20 and the electrode portion 30 even during use.

  In addition, the fixing | fixed part 50 is not restricted to a double-sided tape, For example, an adhesive agent may be sufficient. Also in this case, as in the case of the double-sided tape, the lower surface covering portion 41 of the insulating film 40 is fixed to the lower surface portion 11b with an adhesive applied to the surface inside the case 10 of the lower surface portion 11b.

  The fixing portion 50 is interposed between the side peripheral surface covering portion 42 of the insulating film 40 and the side peripheral portion 11a of the case 10, and fixes the side peripheral surface covering portion 42 and the side peripheral portion 11a. May be. Also in this case, a double-sided tape or an adhesive can be used as the fixing portion 50. The fixing of the side peripheral surface covering portion 42 and the side peripheral portion 11a via the fixing portion 50 may be performed using expansion during charging of the electrode assembly 20. That is, when charging, the electrode assembly 20 expands in the stacking direction of the electrode sheets. Before charging, the fixing portion 50 is provided on the side peripheral portion 11a, and the insulation covers the expanded electrode assembly 20 by charging. The side peripheral surface covering portion 42 and the fixing portion 50 of the film 40 may be brought into contact with each other to fix the side peripheral surface covering portion 42 and the side peripheral portion 11a via the fixing portion 50.

  However, as shown in FIGS. 1 and 3, the fixing portion 50 fixes the lower surface covering portion 41 of the insulating film 40 and the lower surface portion 11 b of the case 10, so that the heat dissipation of the secondary battery 1 is not hindered. it can.

  That is, in the side peripheral surface 21, the coated surface side peripheral surface 21a coated with the active material is likely to generate heat, but the fixing portion 50 having a low thermal conductivity is not provided at a location corresponding to the coated surface side peripheral surface 21a. Thereby, the heat dissipation in the side peripheral surface 21 is maintained. Further, the lower surface covering portion 41 that covers the lower surface 23 is a portion that is fixed to the case 10 by the fixing portion 50, and the fixed portion and the heat radiating portion are formed by using the side peripheral surface 21 having a larger area than the lower surface 23 as a heat radiating portion As compared with the case (the case where the side peripheral surface covering portion is fixed by the fixing portion 50 and the lower surface 23 is the heat radiating portion), high heat dissipation can be realized.

  In the secondary battery 1, the connecting tape 60 partially covers the upper surface 22 and is connected to the side peripheral surface covering portion 42 of the insulating film 40, so that the insulating film 40 is securely attached to the electrode assembly 20. The electrode assembly 20 can be prevented from coming out of the bag-like insulating film 40. In addition, since the connection tape 60 is an insulating tape, even if the electrode assembly 20 and the electrode portion 30 are in contact with each other by covering the upper surface 22 with the connection tape, the positive electrode and the negative electrode in the electrode assembly 20 are used. And the electrode part 30 can be prevented from coming into direct contact. However, the connection tape 60 is not necessarily an insulating tape.

  In addition, this invention is not limited to the said embodiment, A various deformation | transformation is possible.

  As the connection part, the connection tape 60 separate from the insulating film 40 is shown, but the connection tape 60 is not limited to this. For example, as shown in FIG. The upper surface 22 may be partially covered by a tongue portion 42 a that extends integrally from the side surface and extends to the other side peripheral surface covering portion 42.

  In addition, the power storage device is not limited to a secondary battery, and may be another power storage device (for example, an electric double layer capacitor).

  Further, the case 10 has been described as having a configuration in which the upper surface portion 12 blocks the upper opening of the battery can 11 having the side peripheral portion 11a and the lower surface portion 11b formed integrally with the side peripheral portion 11a. For example, the side circumferential portion, the upper surface portion, and the lower surface portion are made of different members, and the upper surface portion of the side circumferential portion is closed by the upper surface portion, and the lower opening is blocked by the lower surface portion. May be.

DESCRIPTION OF SYMBOLS 1 ... Secondary battery, 10 ... Case, 11a ... Side peripheral part, 11b ... Lower surface part, 12 ... Upper surface part, 20 ... Electrode assembly, 21 ... Side peripheral surface, 22 ... Upper surface, 23 ... Lower surface, 30 ... Electrode part , 40 ... insulating film, 41 ... lower surface covering part, 42 ... side peripheral surface covering part, 42a ... tongue part, 50 ... fixing part, 60 ... connection tape.

Claims (5)

A power storage device comprising a case, an electrode assembly housed in the case, and an electrode unit for taking out power to the outside,
The case includes a cylindrical side peripheral portion, an upper surface portion located on the upper side of the side peripheral portion, and a lower surface portion located on the lower side of the side peripheral portion,
The electrode assembly faces the electrode assembly side circumferential surface facing the side circumferential portion inside the case, the electrode assembly upper surface facing the upper surface portion inside the case, and the lower surface portion inside the case. An electrode assembly lower surface,
The electrode portion is provided on the upper surface portion of the case,
The power storage device further includes
An insulating film fixed to the electrode assembly in a bag shape having a lower surface covering portion covering the lower surface of the electrode assembly and a side peripheral surface covering portion covering the electrode assembly side peripheral surface;
A power storage device comprising: a fixing portion that fixes at least one of the lower surface covering portion and the side peripheral surface covering portion of the insulating film and the case.   The power storage device according to claim 1, wherein the fixing portion fixes the lower surface covering portion of the insulating film and the lower surface portion of the case.   3. The device according to claim 1, further comprising a connection portion fixed to the upper surface of the electrode assembly so as to partially cover the upper surface of the electrode assembly and connected to the side peripheral surface covering portion of the insulating film. Power storage device.   The power storage device according to any one of claims 1 to 3, wherein the electrode assembly is movable relative to the electrode portion within the case. The power storage device according to any one of claims 1 to 4, wherein the power storage device is a secondary battery.

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