JP2010218745A - Laminated battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laminated battery equipped with a sealing structure capable of appropriately sealing a power generation element which consists of a plurality of laminated electrode plates each having an electrode layer through a separator without the need of plurality of times of fusion sealing. <P>SOLUTION: The laminated body is provided with a power generation element with a plurality of electrode plates 10a to 10c having electrode layers 12, 13 laminated through a separator 20. The electrode plates 10a to 10c and the separator 20 are laminated through a sealing member 30 capable of elastic deformation for sealing the power generation element from outside, a hole 14 for degassing is formed at a position further outside than a sealing position with the sealing member 30 on at least either the electrode plates 10a to 10c or the separator 20. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a stacked battery including a power generation element formed by stacking electrode plates having electrode layers via separators.

  In a secondary battery such as a lithium ion secondary battery, there is a technique for sealing a power generation element composed of an electrode layer and an electrolyte layer formed on a current collector from the outside using a heat-fusible seal member. It is known (for example, refer to Patent Document 1).

JP 2004-319210 A

  On the other hand, when a secondary battery such as a lithium ion secondary battery is manufactured, gas is generated at the time of initial charge. Therefore, after the initial charge, it is necessary to remove the gas generated by the initial charge. On the other hand, in the above prior art, the sealing member is heat-sealed (sealing and sealing) in order to seal the power generation element from the outside before the initial charging, and the sealing is performed to remove the gas after the initial charging. There is a problem that it is necessary to employ a process of opening the member and heat-sealing the sealing member again (fusion sealing), and there are many manufacturing processes, and thus productivity is lowered.

  The problem to be solved by the present invention is to provide a seal capable of appropriately sealing a power generating element formed by laminating a plurality of electrode plates having electrode layers via separators without requiring multiple fusion sealing. It is providing the laminated battery provided with a structure.

  According to the present invention, an elastically deformable seal member for sealing from the outside is interposed between an electrode plate having an electrode layer and a separator, and at least one of the electrode plate and the separator is sealed by the seal member The above-mentioned problem is solved by forming a hole for venting at a position on the outer side.

  According to the present invention, it is possible to provide a stacked battery capable of sealing a power generation element formed by stacking a plurality of electrode plates having an electrode layer via a separator without requiring multiple fusion sealing. it can.

FIG. 1 is an exploded perspective view of the stacked battery according to the present embodiment. FIG. 2 is a cross-sectional view taken along the line II-II shown in FIG. 1 of the stacked battery according to the present embodiment. 3A is a perspective view of the seal member according to the present embodiment, FIG. 3B is a cross-sectional view taken along line IIIb-IIIb in FIG. 3A, and FIG. 3C is FIG. It is sectional drawing which follows the IIIc-IIIc line of A). FIG. 4 is a cross-sectional view showing a state of the stacked battery according to the present embodiment during gas removal.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is an exploded perspective view of the multilayer battery 1 according to this embodiment, and FIG. 2 is a cross-sectional view taken along the line II-II shown in FIG. 1 of the multilayer battery 1 according to this embodiment. In the following, the present invention is described by exemplifying a case where it is applied to a lithium ion secondary battery, but the present invention is not particularly limited to a lithium ion secondary battery.

  As shown in FIG. 1, the stacked battery 1 of this embodiment includes an electrode plate 10 a, a separator 20, an electrode plate 10 b, a separator 20, and an electrode plate 10 c, and these are stacked in this order via a seal member 30. It is formed by doing. Note that the number of these layers is not particularly limited to the number shown in FIG. 1, and can be set as appropriate.

  As shown in FIG. 2, the electrode plate 10a includes a current collector 11 and a positive electrode active material layer 11 formed on the current collector 11, and the electrode plate 10b includes a current collector 11 and a current collector. It consists of a positive electrode active material layer 11 and a negative electrode active material layer 12 formed on both surfaces of the electric body 11. The electrode plate 10a and the electrode plate 10b are laminated so that the positive electrode active material layer 11 of the electrode plate 10a and the negative electrode active material layer 12 of the electrode plate 10b face each other through the separator 20 containing an electrolyte. Thus, a single cell layer (power generation element) is formed.

  Similarly, the electrode plate 10 c includes a current collector 11 and a negative electrode active material layer 12 formed on the current collector 11. The electrode plate 10c and the electrode plate 10b described above are opposed to the positive electrode active material layer 11 of the electrode plate 10b and the negative electrode active material layer 12 of the electrode plate 10c through the separator 20 containing an electrolyte. Similarly, a single battery layer (power generation element) is formed.

  The current collectors 11 constituting the electrode plates 10a to 10c are mainly composed of one or more metal powders selected from, for example, aluminum, copper, titanium, nickel, stainless steel (SUS), and alloys thereof. And a current collector metal paste containing a binder (resin) and a solvent. In addition, it does not specifically limit as a binder, For example, conventionally well-known resin binder materials, such as an epoxy resin, a conductive polymer material, etc. can be used.

  As shown in FIGS. 1 and 2, each current collector 11 constituting the electrode plates 10 a to 10 c has a pair of vent holes 14 on the outer peripheral side of the arrangement position of the seal member 30. , Each is formed. As shown in FIG. 2, the pair of vent holes 14 are located on the outer peripheral side with respect to rubber seals 32 (first seal portion 32 a and second seal portion 32 b) that constitute a seal portion of a seal member 30 to be described later. Is formed. As will be described later, in the present embodiment, when gas is generated inside the stacked battery 1, the gas generated from the degassing hole 14 can be removed. .

The positive electrode active material layer 12 constituting the electrode plates 10a and 10b contains a positive electrode active material. In addition to the positive electrode active material, the positive electrode active material layer 12 may contain a conductive additive and an electrolyte. As the positive electrode active material, a composite oxide of a transition metal and lithium can be used. Specifically, Li · Co-based composite oxide such as LiCoO _2, Li · Ni-based composite oxide such as LiNiO _2, Li · Mn-based composite oxide such as spinel LiMn ₂ O _4, Li · such LiFeO ₂ Examples thereof include Fe-based composite oxides. In addition, transition metal and lithium phosphate compounds and sulfate compounds such as LiFePO ₄ ; transition metal oxides and sulfides such as V ₂ O ₅ , MnO ₂ , TiS ₂ , MoS ₂ , and MoO ₃ ; PbO ₂ , AgO, NiOOH etc. are mentioned. Examples of the conductive assistant include acetylene black, carbon black, and graphite.

  As the electrolyte, in addition to the electrolytic solution, a gel electrolyte in which about several to 98% by weight of the electrolytic solution is held in the polymer skeleton can be used.

The electrolytic solution is obtained by dissolving an electrolyte salt in a plasticizer. Examples of the electrolyte salt include inorganic acid anion salts such as LiPF ₆ , LiBF ₄ , LiClO ₄ , LiAsF ₆ , LiTaF ₆ , LiAlCl ₄ , Li ₂ B ₁₀ Cl ₁₀ ; LiCF ₃ SO ₃ , Li (CF ₃ SO ₂ ) _2. And organic acid anion salts such as N and Li (C ₂ F ₅ SO ₂ ) ₂ N; Examples of the plasticizer include cyclic carbonates such as propylene carbonate and ethylene carbonate; chain carbonates such as dimethyl carbonate, methyl ethyl carbonate and diethyl carbonate; tetrahydrofuran, 2-methyltetrahydrofuran, 1,4-dioxane, 1,2 -Ethers such as dimethoxyethane and 1,2-dibutoxyethane; Lactones such as γ-butyrolactone; Nitriles such as acetonitrile; Esters such as methyl propionate; Amides such as dimethylformamide; Methyl acetate and methyl formate And the like.

  As the polymer constituting the gel electrolyte, for example, polyvinylidene fluoride (PVDF), polyvinyl chloride (PVC), polyacrylonitrile (PAN), polymethyl methacrylate (PMMA) and the like can be used.

  The negative electrode active material layer 13 constituting the electrode plates 10b and 10c contains a negative electrode active material. Moreover, the negative electrode active material layer 13 may contain a conductive additive and an electrolyte in addition to the negative electrode active material. Examples of the negative electrode active material include metal oxide, lithium-metal composite oxide metal, soft carbon, and hard carbon. Moreover, what was mentioned above can be used as a conductive support agent and electrolyte.

  The separator 20 is a microporous membrane made of, for example, polyolefin such as polyethylene (PE) or polypropylene (PP), cellulose, and the like, and contains an electrolyte. In addition, as an electrolyte contained in the separator 20, those described above can be used.

  In addition, in order to improve the pressure-bonding force with the first seal part 32a on the part of the surface of the separator 20 to be pressure-bonded with the first seal part 32a of the rubber seal 32 constituting the seal member 30 described later, The crimping | compression-bonding process may be given.

  In addition, a pair of electrode leads for taking out the electric power from the stacked battery 1 may be formed on the lower surface of the electrode plate 10a and the lower surface of the electrode plate 10c. From the standpoint of not reducing the efficiency, it is desirable to have a configuration derived in the same direction as the direction in which the lead-out portion 31a formed in the seal carrier 31 constituting the seal member 30 described later is formed.

Next, the seal member 30 interposed between the electrode plates 10a to 10c and the separator 20 will be described.
3A is a perspective view of the seal member 30, FIG. 3B is a cross-sectional view taken along line IIIb-IIIb in FIG. 3A, and FIG. 3C is FIG. 3A. It is sectional drawing which follows the IIIc-IIIc line.

  As shown in FIGS. 3A to 3C, the seal member 30 is formed by attaching a pair of rubber seals 32 to the upper and lower surfaces of a frame-shaped seal carrier 31 made of an elastically deformable material. With this, the seal carrier 31 and the pair of rubber seals 32 are integrated. As shown in FIG. 3A, the seal carrier 31 is formed with a drawer portion 31a.

  The material constituting the seal carrier 31 constituting the seal member 30 may be an elastically deformable material, and is not particularly limited. For example, various resin materials such as PET resin can be used. Also, a method of attaching the seal carrier 31 and the pair of rubber seals 32 and integrating them is not particularly limited, and for example, various adhesive materials may be used. In the present embodiment, a pair of rubber seals 32 are attached to the upper and lower surfaces of the seal carrier 31 so that they are integrated. For example, the rubber seal 32 is fitted into the seal carrier 31. The seal carrier 31 and the rubber seal 32 may be integrated.

  As shown in FIG. 3A, the pair of rubber seals 32 constituting the seal member 30 has a first seal portion 32a (see FIG. 3B) having a relatively wide seal width and a first seal portion having a relatively narrow seal width. 2 seal portions 32b (see FIG. 3C). In the present embodiment, among these, the second seal portion 32b is formed in the lead-out portion 31a formed in the seal carrier 31 and the electrode plates 10a to 10c, as shown in FIGS. 1, 2, and 3A. It is arranged at a position corresponding to the degassing hole 14. On the other hand, the first seal portion 32a, which is a portion other than the second seal portion 32b, is disposed at other positions.

  Further, the thickness of the seal member 30 (that is, the total thickness of the seal carrier 31 and the pair of rubber seals 32) is not particularly limited, but the positive electrode active material layer 12 and the negative electrode active material layer constituting each of the electrode plates 10a to 10c. The thickness may be approximately the same as 13 or slightly thicker than these.

  As shown in FIG. 2, the sealing member 30 having such a configuration is arranged on the outer periphery of the positive electrode active material layer 12 and the negative electrode active material layer 13 constituting each of the electrode plates 10 a to 10 c. And it arrange | positions between each electrode plate 10a-10c and the separator 20 so that the negative electrode active material layer 13 may be enclosed. And each electrode plate 10a-10c and the separator 20 are mutually crimped | bonded with the rubber seal 32 (the 1st seal | sticker part 32a and the 2nd seal | sticker part 32b) of each sealing member 30 on the surface, Thereby, the electrode plate 10a A cell layer composed of the positive electrode active material layer 11, the negative electrode active material layer 12 of the electrode plate 10b, and the separator 20 impregnated with the electrolyte, and the positive electrode active material layer 11 of the electrode plate 10b and the electrode plate 10c A unit cell layer composed of the negative electrode active material layer 12 and the separator 20 impregnated with the electrolyte is sealed from the outside.

  Here, as shown in FIG. 3, the second seal portion 32 b of the rubber seal 32 has a narrower seal width than the first seal portion 32 a which is another portion of the rubber seal 32. (Refer FIG.3 (B) and FIG.3 (C)), and, thereby, the crimping | compression-bonding force with respect to each electrode plate 10a-10c and the separator 20 is lower than the 1st seal | sticker part 32a. On the other hand, the first seal portion 32a, which is a portion other than the second seal portion 32b, has a wider seal width than the second seal portion 32b. The crimping force against 10c and the separator 20 is high.

  Therefore, in the present embodiment, when the gas is generated inside the stacked battery 1 and the internal pressure inside the stacked battery 1 rises due to the generated gas, the second seal portion 32b of the seal carrier 31 is used. Only the portion where the is formed is elastically deformed, so that only the second seal portion 32b moves to the outer peripheral side of the stacked battery 1 as shown in FIG. As a result, as shown by arrows in FIG. 4, the generated gas is removed from each unit cell layer through the vent holes 14 formed in the electrode plates 10 a to 10 c. It becomes.

  That is, in this embodiment, when gas is generated inside the stacked battery 1 and the internal pressure inside the stacked battery 1 is increased, the pressure is applied to the electrode plates 10a to 10c and the separator 20 due to the increased internal pressure. The second seal portion 32b, which is a portion with a low force, moves to the outer peripheral side, while the first seal portion 32a, which is a portion with a high pressure bonding force, does not move. Therefore, in this embodiment, when gas is generated inside the stacked battery 1 and the internal pressure of the stacked battery 1 is increased, only the second seal portion 32b is provided in the stacked battery 1 as shown in FIG. It will move to the outer peripheral side. FIG. 4 is a cross-sectional view showing a state of the stacked battery according to the present embodiment during gas removal, and is a cross-sectional view in the same cross section as the cross-sectional view shown in FIG.

  When the generated gas is removed, the internal pressure of the stacked battery 1 is reduced due to the removal of the generated gas. Therefore, the second seal portion 32b is caused by the elastic force of the rubber seal 32. Returning to the original position, each single cell layer is again sealed. That is, the stacked battery 1 returns to the state shown in FIG.

  Alternatively, in the present embodiment, when gas is generated inside the stacked battery 1, the drawer portion 31 a formed on the seal carrier 31 is pulled to the outer peripheral side. As described above, the generated gas may be removed by elastically deforming the seal carrier 31 and moving the second seal portion 32b to the outer peripheral side. Even in this case, after the generated gas is removed, the second sealing portion 32b is returned to the original position by the elastic force of the rubber seal 32 by releasing the tensile force on the drawer portion 31a. Each single cell layer is sealed.

  According to this embodiment, the rubber seal part 32 which forms the hole part 14 for degassing in the collector 11 which comprises each electrode plate 10a-10c, and comprises the seal part which seals each cell layer. The 2nd seal | sticker part 32b which is a part of it is set as the structure which can move. Therefore, according to the present embodiment, when the gas is generated inside the stacked battery 1 and the internal pressure inside the stacked battery 1 is increased due to the generation of the gas, the second seal portion 32b is elastically deformed and the second seal The sealing position by the part 32b moves, and thereby the generated gas is removed from the degassing hole 14, and then the second sealing part 32b is returned to the original position by the elastic force of the rubber seal part 32. Can do. Alternatively, when gas is generated inside the stacked battery 1, the drawer portion 31 a formed on the seal carrier 31 is pulled to the outer peripheral side of the stacked battery 1, so that the sealing by the second seal portion 32 b is performed. The position can be moved, so that the generated gas is removed from the degassing hole 14, and then the tensile force on the drawer 31a is released, so that the elastic force of the rubber seal 32 causes the first 2 The seal part 32b can be returned to the original position.

  Therefore, according to the present embodiment, even when gas is generated inside the stacked battery 1, in order to remove the generated gas, the process of opening and sealing the stacked battery 1 again is unnecessary. The gas generated inside the stacked battery 1 can be appropriately removed. Furthermore, according to the present embodiment, by appropriately removing the gas generated in the multilayer battery 1, it is possible to effectively prevent the occurrence of damage due to the gas generation of the multilayer battery 1 as a result. It becomes possible.

  As mentioned above, although embodiment of this invention was described, these embodiment was described in order to make an understanding of this invention easy, and was not described in order to limit this invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

  For example, in the above-described embodiment, the configuration in which the rubber seal 32 is formed over the entire circumference of the seal member 30 is shown. However, it is not always necessary to form the rubber seal 32 over the entire circumference, for example, only the portion corresponding to the second seal portion 32b. The rubber seal 32 is formed on the other portion, and the portion corresponding to the first seal portion 32a, which is the other portion, is brought into close contact with the electrode plates 10a to 10c and the separator 20 by other methods such as a method of bonding with an adhesive. Thus, a sealing structure may be formed.

  Moreover, in embodiment mentioned above, although the structure which forms the hole 14 for degassing in the electrical power collector 11 which comprises each electrode plate 10a-10c was illustrated, the hole 14 for degassing was illustrated. It is good also as a structure formed in the separator 20. FIG.

  Further, in the above-described embodiment, the stacked battery 1 is exemplified as a so-called bipolar battery including a plurality of single battery layers. However, the stacked battery 1 may be configured as a single single battery. .

DESCRIPTION OF SYMBOLS 1 ... Stack type battery 10a, 10b, 10c ... Electrode plate 11 ... Current collector 12 ... Positive electrode active material layer 13 ... Negative electrode active material layer 14 ... Hole for venting 20 ... Separator 30 ... Seal member 31 ... Seal carrier 31a ... Drawer 32 ... Rubber seal 32a ... First seal 32b ... Second seal

Claims (6)

A power generation element comprising a plurality of electrode plates having electrode layers stacked via a separator,
The electrode plate and the separator are laminated via an elastically deformable seal member for sealing the power generation element from the outside,
A laminated battery, wherein at least one of the electrode plate and the separator is formed with a gas venting hole at a position outside a sealing position by the sealing member. The stacked battery according to claim 1,
The laminated battery according to claim 1, wherein the seal member includes a movable part that moves outward from a position where the hole is formed. The stacked battery according to claim 2,
The movable battery is characterized in that the movable part is movable so that gas generated inside the power generation element is removed from the hole. The stacked battery according to claim 2 or 3,
The stacked battery is characterized in that the seal member is configured such that a seal width of the movable portion is narrower than a seal width of a portion other than the movable portion. The stacked battery according to any one of claims 1 to 4,
The seal member includes a seal carrier and seal means for sealing the power generation element from the outside.
At least a part of the sealing means is formed of a rubber seal. The stacked battery according to claim 5,
The stacked battery according to claim 1, wherein the sealing member is formed with a lead-out portion for moving the movable portion.

Images