Film-encased battery

Abstract

To provide a film-covered battery capable of suppressing deterioration in insulation between an electrode body and a metal layer included in a laminate film.SOLUTION: A film-covered battery 10 includes: an electrode body which has a positive electrode and a negative electrode disposed to face each other with a separator interposed therebetween; a film exterior body 11 which accommodates the electrode body; a connection terminal 13a which includes a flat metal member 13a1 electrically connected to the positive electrode and partially projecting from the film exterior 11, and in which the metal member 13a1 at a portion projecting from the film exterior body 11 is exposed on the entire surface of a first surface and an insulator 13a2 is formed on at least a part of a second surface facing the first surface; and a connection terminal 13b which includes a flat metal member 13b1 electrically connected to the negative electrode and partially projecting from the film exterior 11, and in which the metal member 13b1 at a portion projecting from the film exterior body 11 is exposed on the entire surface of a third surface facing the same direction as the first surface and an insulator 13b2 is formed on at least a part of a fourth surface facing the third surface.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a film-covered battery. [Background technology]

[0002] Extremely thin electronic devices (hereafter referred to as "thin electronic devices") that have built-in power sources are now in practical use, such as IC cards with one-time password functions and displays, or tags and tokens (one-time password generators). To realize these thin electronic devices, it is essential to make the energy storage elements (primary batteries, secondary batteries, electric double-layer capacitors, etc.) that serve as their power sources smaller and thinner.

[0003] Film-cased batteries are energy storage elements suitable for miniaturization and thinning (see, for example, Non-Patent Document 1). Film-cased batteries have an electrode assembly housed in a film casing made of aluminum laminate film or the like. The electrode assembly has a positive electrode and a negative electrode that are arranged opposite each other with a separator interposed between them. A connection terminal electrically connected to the positive electrode and a connection terminal electrically connected to the negative electrode protrude from the film casing. These connection terminals are also called tab leads.

[0004] When a battery is incorporated into a device, the battery's connection terminals are electrically connected to the device's circuitry. Connection methods include soldering, ultrasonic welding, and resistance welding, but these methods make it impossible to remove the battery. One method that allows the battery to be removed is to insert the battery's connection terminals into the device's connector socket.

[0005] In addition, in the past, there was a technology to form a resin material or the like on the surface of the connection terminal in order to improve adhesion between the connection terminal of the secondary battery and the sealing material (sealant) provided between the connection terminal and the film exterior body (see, for example, Patent Documents 1 and 2).

[0006] Furthermore, there is a technology in which a film exterior is formed to cover one side of the connection terminal to prevent deformation of the connection terminal (see, for example, Patent Document 3). However, this technology is not designed to insert the connection terminal into a connector socket, and so the film exterior gets in the way when connecting the battery to the connector.

[0007] Furthermore, in order to prevent bending of the connection terminals protruding from the film exterior, there is a technique in which a support sheet is provided by extending part of the film exterior outward, and the connection terminals are placed on top of this (see, for example, Patent Document 4).

[0008] Furthermore, in a structure in which multiple battery cells are stacked, there is a technology in which an insulating film is provided on both sides of the connection terminals between adjacent battery cells to prevent contact between the connection terminals protruding from each battery cell (see, for example, Patent Document 5). [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-159569 [Patent Document 2] Japanese Patent Application Laid-Open No. 2016-157516 [Patent Document 3] Japanese Patent Application Laid-Open No. 2001-102014 [Patent Document 4] Japanese Patent Application Publication No. 2019-057521 [Patent Document 5] Special Publication No. 2018-526802 [Non-patent literature]

[0010] [Non-Patent Document 1] FDK Corporation, "Thin Manganese Dioxide Lithium Primary Battery," [online], [Retrieved December 10, 2020], Internet<URL:https: / / www.fdk.co.jp / battery / lithium / thin / > Summary of the Invention [Problem to be solved by the invention]

[0011] When a battery is made removable from a device's connector, there is a possibility that the battery's negative terminal may come into contact with the positive terminal of the connector, and the positive terminal may come into contact with the negative terminal of the connector. If this happens, a reverse current may flow in the device's circuit, including the connector, potentially destroying the device.

[0012] One possible method for preventing reverse connection of positive and negative electrodes between the battery connection terminals and connector is to make the shape of the connection terminals and the connector socket asymmetrical, such as trapezoidal, so that they can only be inserted in the correct orientation. However, in the case of film-covered batteries such as those described above, the connection terminals are thin, making it difficult to devise a unique shape.

[0013] In one aspect, the present invention aims to provide a film-covered battery that can protect equipment including a connector even if reverse connection of positive and negative poles occurs between the connection terminals of the film-covered battery and the connector. [Means for solving the problem]

[0014] In one embodiment, a film-covered battery is provided, comprising: an electrode assembly having a positive electrode and a negative electrode arranged opposite each other with a separator interposed therebetween; a film exterior housing that houses the electrode assembly; a first connection terminal that includes a flat-shaped first metal member electrically connected to the positive electrode and a portion of which protrudes from the film exterior housing, the first metal member being exposed over the entire surface of a first surface of the portion protruding from the film exterior housing, and a first insulator being formed on at least a portion of a second surface opposite the first surface; and a second connection terminal that includes a flat-shaped second metal member electrically connected to the negative electrode and a portion of which protrudes from the film exterior housing, the second metal member being exposed over the entire surface of a third surface of the portion protruding from the film exterior housing that faces the same direction as the first surface, and a second insulator being formed on at least a portion of a fourth surface opposite the third surface. [Effects of the Invention]

[0015] According to one aspect, the present invention can protect a device including a connector even if a reverse connection of positive and negative electrodes occurs between the connection terminals of a film-covered battery and the connector. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a perspective view showing an example of a film-covered battery according to the present embodiment. [Figure 2] FIG. 2 is a side view of a portion of the film-covered battery of the present embodiment. [Figure 3] FIG. 2 is a perspective view schematically showing layers included in the film-covered battery of the present embodiment. [Figure 4] FIG. 1 is a diagram showing a first application example of a film-covered battery. [Figure 5] 10 is a diagram showing an example in which the connection terminals of a film-covered battery are inserted into the connector socket with the positive and negative terminals facing inversely. FIG. [Figure 6] FIG. 10 is a diagram showing a second application example of a film-covered battery. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, embodiments of the invention will be described with reference to the drawings. Fig. 1 is a perspective view showing an example of a film-covered battery of the present embodiment, Fig. 2 is a side view of a portion of the film-covered battery of the present embodiment, and Fig. 3 is a perspective view schematically showing layers included in the film-covered battery of the present embodiment.

[0018] 1 to 3, the film-covered battery 10 of this embodiment has an electrode assembly 12 having a positive electrode 12a and a negative electrode 12b arranged opposite each other with a separator 12c interposed therebetween, and a film covering 11 made of laminate films 11a and 11b that houses the electrode assembly 12. The film-covered battery 10 also has a connection terminal 13a electrically connected to the positive electrode 12a and a connection terminal 13b electrically connected to the negative electrode 12b.

[0019] The laminate films 11a and 11b are thermally laminated, for example, by extrusion lamination, and are formed by sandwiching a metal layer made of, for example, foil aluminum or stainless steel between a resin layer and a heat-sealing layer.

[0020] As shown in FIG. 3, tab films 14a and 14b are attached to the sides of the laminate films 11a and 11b that contact the connection terminals 13a and 13b. The film exterior body 11 made of such laminate films 11a and 11b has its heat-sealed layers heat-sealed to each other in the peripheral region, and is processed into a bag shape so as to enclose the electrode body 12 and the non-aqueous organic electrolyte solution.

[0021] The positive electrode 12a is formed by disposing a positive electrode material containing a positive electrode active material on one main surface of a current collector which is, for example, a metal plate or metal foil made of stainless steel or the like. The separator 12c is made of, for example, a cellulose product.

[0022] The negative electrode 12b is formed by disposing a negative electrode material containing a negative electrode active material on one main surface of a current collector which is, for example, a metal plate or metal foil made of stainless steel or the like. When the film-covered battery 10 is a lithium primary battery, the positive electrode 12a is a current collector coated with a slurry positive electrode material containing a positive electrode active material such as MnO2 (manganese dioxide), and the negative electrode 12b is a foil or flat plate of metallic lithium or a lithium alloy without a current collector.

[0023] The electrode body 12 may be heat-welded to the laminate films 11a and 11b to prevent misalignment. Connection terminal 13a electrically connected to positive electrode 12a includes flat metal member 13a1, a portion of which protrudes from film exterior body 11. Connection terminal 13b electrically connected to negative electrode 12b also includes flat metal member 13b1, a portion of which protrudes from film exterior body 11.

[0024] The metal member 13a1 is, for example, a metal plate such as stainless steel, and the metal member 13b1 is, for example, a metal plate made of an alloy of Cu (copper) and Ni (nickel). Furthermore, in connection terminal 13a, metal member 13a1 is exposed over the entire first surface of the portion protruding from film exterior body 11, and insulator 13a2 is formed on at least a portion of the second surface opposite the first surface.

[0025] Similarly, for connection terminal 13b, a metal member 13b1 is exposed over the entire surface of the third surface, which faces the same direction as the first surface, of the portion protruding from film exterior body 11, and an insulator 13b2 is formed on at least a portion of the fourth surface opposite the third surface.

[0026] The first to fourth surfaces are surfaces whose normal vectors are in the thickness direction of the film-covered battery 10 (the z-axis direction in FIGS. 2 and 3). 1 to 3, the insulators 13a2 and 13b2 are formed on the tip sides of the second and fourth surfaces of the connection terminals 13a and 13b in the portions thereof that protrude from the film exterior body 11, but this is not limiting. The insulators 13a2 and 13b2 may be formed only in the intermediate portions between the base and the tip of the connection terminals 13a and 13b in the portions thereof that protrude from the film exterior body 11, or may be formed only on the base side.

[0027] In addition, the insulators 13a2, 13b2 may be formed on the second and fourth surfaces, and may also be formed on the tip surfaces of the portions of the connection terminals 13a, 13b that protrude from the film exterior body 11 (surfaces perpendicular to the first to fourth surfaces).

[0028] The insulators 13a2 and 13b2 are preferably formed by attaching a resin film or the like having an area equal to or smaller than the second and fourth surfaces to the metal members 13a1 and 13b1 after assembling the film-covered battery 10. This is because they are easy to form.

[0029] However, the method for forming the insulators 13a2 and 13b2 is not limited to the above example. For example, the insulators 13a2 and 13b2 may be applied to the second and fourth surfaces, or may be formed by insulating processing such as anodizing.

[0030] Furthermore, the insulators 13a2 and 13b2 are not limited to resin. For example, the insulators 13a2 and 13b2 may be ceramic. Furthermore, the insulators 13a2 and 13b2 may be made of different materials.

[0031] (Manufacturing example) An example of manufacturing the film-covered battery 10 will be described below. The positive electrode 12a is obtained by applying a water-based slurry of a positive electrode material to one main surface of a stainless steel current collector, except for the area where the metal member 13a1 of the connection terminal 13a will be formed. The positive electrode material is, for example, adjusted to a composition of 90.2 parts by weight of MnO2, 5 parts by weight of AB (acetylene black), 3.7 parts by weight of SBR (styrene-butadiene rubber), and 0.8 parts by weight of HEC (hydroxyethyl cellulose).

[0032] MnO2 is the positive electrode active material, AB is a conductive additive, SBR is a binder, and HEC is a thickener. The amount of the positive electrode material applied was 31 mg / cm. 2 After coating, the mixture is dried and pressed, and then cut into a piece measuring 20×13 mm (the size of the portion of the connection terminal 13a other than the area where the metal member 13a1 is formed), thereby obtaining the positive electrode 12a.

[0033] At the same time, the metal member 13a1 of the stainless steel connection terminal 13a is also cut out. That is, the metal member 13a1 is manufactured integrally with the stainless steel current collector of the positive electrode 12a.

[0034] The negative electrode 12b is obtained by cutting metallic lithium into a piece measuring, for example, 19×12 mm. The separator 12c is made of a cellulose product having a thickness of 20 μm.

[0035] The electrode assembly 12 is formed by laminating a positive electrode 12a, a separator 12c, and a negative electrode 12b in this order. Such an electrode assembly 12 is obtained by bonding together a positive electrode 12a heat-sealed to the heat-sealing layer of a laminate film 11a and a negative electrode 12b heat-sealed to the heat-sealing layer of a laminate film 11b with a separator 12c sandwiched therebetween.

[0036] Tab films 14a and 14b are attached to the laminate films 11a and 11b in advance. As described above, the metal member 13a1 of the connection terminal 13a, which is formed simultaneously with the positive electrode 12a, is connected to the positive electrode 12a. The metal member 13b1 of the connection terminal 13b is disposed between the thermal fusion layer of the laminate film 11b and the negative electrode 12b, and is thereby electrically connected to the negative electrode 12b.

[0037] With the electrode assembly 12 inserted, three of the four peripheral sides of the laminate films 11a and 11b are adhered and sealed together to produce a bag-shaped film exterior body 11 with one side open. A non-aqueous organic electrolyte solution is then injected through the opening of the film exterior body 11, impregnated under reduced pressure, and then vacuum sealed (the remaining side is sealed).

[0038] After sealing, a 180 μm thick PET (Polyethylene Terephthalate) film with adhesive is attached to the surfaces (the second and fourth surfaces) of the metal members 13a1 and 13b1 that face in the same direction and protrude from the film sheath 11. This completes the film-covered battery 10.

[0039] The above manufacturing method is merely an example, and the manufacturing conditions can be changed as appropriate. (Application examples and effects) Hereinafter, application examples and effects of the film-covered battery of this embodiment will be described.

[0040] FIG. 4 is a diagram showing a first application example of a film-covered battery. The connection terminals 13a and 13b of the film-covered battery 10 are inserted into the sockets 21a and 21b of the connector 20a.

[0041] Socket 21a is for the positive electrode (marked "+"), and socket 21b is for the negative electrode (marked "-"). A positive terminal and a negative terminal are provided inside connector 20a so that only the bottom surfaces of connection terminals 13a and 13b inserted into sockets 21a and 21b come into contact with each other.

[0042] Therefore, as shown in Figure 4, when the connection terminals 13a, 13b of the film-covered battery 10 are inserted into the sockets 21a, 21b with the positive and negative terminals facing in the correct direction, power is normally supplied from the film-covered battery 10 to the connector 20a.

[0043] On the other hand, if the connection terminals 13a, 13b of the film-covered battery 10 are inserted into the sockets 21a, 21b in the opposite positive and negative directions, the insulators 13a2, 13b2 of the connection terminals 13a, 13b will come into contact with the positive and negative terminals of the connector 20a.

[0044] FIG. 5 shows an example in which the connection terminals of a film-covered battery are inserted into the connector socket with the positive and negative terminals facing inversely. 5, connection terminal 13b electrically connected to negative electrode 12b is inserted into positive electrode socket 21a. In this case, insulator 13b2 of connection terminal 13b contacts positive electrode terminal 22a of connector 20a, and metal member 13b1 of connection terminal 13b does not contact positive electrode terminal 22a.

[0045] This prevents electrical conduction between the film-covered battery 10 and the connector 20a, suppressing the occurrence of reverse current and protecting the device including the connector 20a, thereby ensuring the safety of the device.

[0046] One possible solution is to design the connection terminals 13a, 13b and the sockets 21a, 21b as asymmetrical, such as trapezoidal, to ensure they can only be inserted in the correct orientation. However, in the film-covered battery 10 described above, the connection terminals 13a, 13b are thin, making it difficult to devise a suitable shape. According to the film-covered battery 10 of this embodiment, by providing the insulators 13a2, 13b2 described above on the connection terminals 13a, 13b, even with thin connection terminals 13a, 13b, the device including the connector 20a can be protected in the event of a reverse connection of the positive and negative electrodes, as described above. This is particularly effective when the thickness of the film-covered battery 10 is 1 mm or less, making it difficult to thicken the connection terminals 13a, 13b.

[0047] Furthermore, the film-covered battery 10 can be inserted and removed from the connector 20a. This allows the battery to be replaced when it reaches the end of its life. In particular, in devices that use non-rechargeable primary batteries, making the battery removable allows for repeated use by simply replacing the battery even after the electronic capacity has run out, making the film-covered battery 10 particularly effective when it is a primary battery.

[0048] For example, if the film-covered battery 10 is a lithium primary battery, as described above, the positive electrode 12a may be a slurry positive electrode material containing a positive electrode active material such as MnO2 applied to one main surface of a current collector, and the negative electrode 12b may be a foil or flat plate of metallic lithium or a lithium alloy.

[0049] FIG. 6 is a diagram showing a second application example of a film-covered battery. 6, connector 20b is an open / close type, and has a plurality of positive terminals (e.g., positive terminal 23a) and a plurality of negative terminals (e.g., negative terminal 23b) formed on the base portion. In such connector 20b, the lower surfaces of connection terminals 13a and 13b come into contact with one of the plurality of positive terminals and one of the plurality of negative terminals when connector 20b is in the closed state.

[0050] As shown in Figure 6, when connection terminal 13a of film-covered battery 10 contacts one of the multiple positive terminals of connector 20b and connection terminal 13b contacts one of the multiple negative terminals of connector 20b, power is normally supplied to connector 20b from film-covered battery 10.

[0051] On the other hand, when connection terminal 13a of film-covered battery 10 contacts one of the multiple negative terminals of connector 20b and connection terminal 13b contacts one of the multiple negative terminals of connector 20b, insulators 13a2 and 13b2 of connection terminals 13a and 13b come into contact with one of the multiple positive terminals and one of the multiple negative terminals of connector 20b.

[0052] Therefore, even when such a connector 20b is used, if the positive and negative electrodes are reversed, electrical conduction between the film-covered battery 10 and the connector 20b is prevented, preventing the occurrence of reverse current, thereby protecting the device including the connector 20a and ensuring the safety of the device.

[0053] While one aspect of the film-covered battery of the present invention has been described above based on the embodiment, this is merely an example and the present invention is not limited to the above description. [Explanation of symbols]

[0054] 10 Film-encased batteries 11 Film exterior 11a, 11b Laminate film 12 Electrode body 12a positive electrode 12b negative electrode 12c separator 13a, 13b connection terminals 13a1, 13b1 Metallic members 13a2, 13b2 Insulators 14a, 14b Tab film

Claims

1. an electrode assembly having a positive electrode and a negative electrode arranged opposite each other with a separator interposed therebetween; a film exterior body that houses the electrode body; a first connection terminal including a flat-shaped first metal member electrically connected to the positive electrode and a portion of which protrudes from the film exterior housing, the first metal member being exposed over the entire first surface of the portion protruding from the film exterior housing, and a first insulator separated from the film exterior housing being formed on a second surface opposite the first surface and on a portion of the portion protruding from the film exterior housing; a second connection terminal including a flat second metal member electrically connected to the negative electrode and having a portion protruding from the film exterior housing, the second metal member being exposed over the entire surface of a third surface of the portion protruding from the film exterior housing, the third surface facing the first surface, and a second insulator separated from the film exterior housing and the first insulator being formed on a portion of the portion protruding from the film exterior housing on a fourth surface opposite the third surface; A film-covered battery comprising:

2. 2. The film-covered battery according to claim 1, wherein the first insulator and the second insulator are resin.

3. 3. The film-covered battery according to claim 1, wherein the thickness is 1 mm or less.

4. 4. The film-covered battery according to claim 1, wherein the film-covered battery is a primary battery.

5. 5. The film-covered battery according to claim 1, wherein the positive electrode contains manganese dioxide as a positive electrode active material, and the negative electrode is metallic lithium or a lithium alloy.

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