Battery

Abstract

To provide a battery in which a fixing member is less likely to peel off from an electrode stack, and in which localized pressure concentration on the electrode stack caused due to inclusion of the electrode a fixing member in the stack.SOLUTION: A battery 1 according to the present disclosure includes: an electrode stack 10; and a pair of current collecting terminals 20 disposed on first and second opposing side surface portions 10a, 10b of the electrode stack 10. The battery according to the present disclosure includes fixing members 30 disposed extending across the side surface portions of the pair of current collecting terminals and across third and fourth opposing side surface portions 10c, 10d of the electrode stack between the pair of current collecting terminals.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to batteries. [Background technology]

[0002] Batteries are known that use an electrode stack, in which a negative electrode current collector layer, a negative electrode active material layer, an electrolyte layer, a positive electrode active material layer, and a positive electrode current collector layer are stacked in this order, as a power generating element of the battery. In such batteries, the positions of the edges of the layers constituting the electrode stack in the planar direction may be misaligned with each other. To solve this problem, a method of fixing the electrode stack using a fixing member has been developed.

[0003] For example, Patent Document 1 discloses a battery in which tape is applied to the upper surface, end surfaces (side surfaces) and lower surface of a laminated electrode body (electrode laminate). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-048054 Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, the volume of the electrode laminate may change during charging and discharging of the battery. That is, the electrode laminate may expand when the battery expands, and may contract when the battery discharges.

[0006] It is desirable that the fixing member does not peel off from the electrode stack even when the volume of the electrode stack changes.

[0007] When the electrode laminate expands, if tape is applied as a fixing member to the upper surface, side surfaces, and lower surface of the electrode laminate, pressure due to the expansion may be concentrated in the areas of the electrode laminate where the tape is applied to the upper and lower surfaces. Therefore, it is desirable to be able to alleviate the local concentration of pressure on the electrode laminate even when the electrode laminate expands.

[0008] The present disclosure aims to provide a battery in which a fixing member is less likely to peel off from an electrode stack and in which the concentration of local pressure on the electrode stack caused by the electrode stack having a fixing member is alleviated. [Means for solving the problem]

[0009] The present inventors have found that the above problems can be solved by the following means. <Aspect 1> A battery having an electrode stack and a pair of current collecting terminals disposed on first and second opposing side surfaces of the electrode stack, a fixing member disposed to extend across the side surfaces of the pair of current collecting terminals and across the opposing third and fourth side surfaces of the electrode stack between the pair of current collecting terminals; A battery having <Aspect 2> 2. The battery of claim 1, wherein the fixing member is an adhesive tape. <Aspect 3> 3. The battery of claim 1, further comprising a laminate film that seals the electrode stack together with the pair of current collecting terminals. [Effects of the Invention]

[0010] According to the present disclosure, it is possible to provide a battery in which the fixing member is less likely to peel off from the electrode stack and in which the concentration of local pressure on the electrode stack caused by the electrode stack having the fixing member is alleviated. [Brief explanation of the drawings]

[0011] [Figure 1]FIG. 1 is a schematic perspective view showing an example of a battery according to the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. Note that the present disclosure is not limited to the following embodiments, and various modifications can be made within the scope of the present disclosure. Furthermore, the dimensional relationships in the drawings do not reflect the actual dimensional relationships.

[0013] "battery" 1 , a battery 1 of the present disclosure includes an electrode stack 10 and a pair of current collecting terminals 20 disposed on first and second opposing side surfaces 10a, 10b of the electrode stack 10. The battery of the present disclosure includes a fixing member 30 disposed to extend across the side surfaces of the pair of current collecting terminals and across third and fourth opposing side surfaces 10c, 10d of the electrode stack between the pair of current collecting terminals.

[0014] One method for fixing the electrode stack is to place a fixing member only on the side surface of the electrode stack. However, this method has the risk of the fixing member peeling off due to expansion of the electrode stack. In this regard, the present inventors have discovered that by placing the fixing member so that it extends over the side surface of the current collector terminal and the side surface of the electrode stack, the fixing member can be made less likely to peel off from the electrode stack. The reason for this is thought to be that the fixing member is more firmly fixed by placing the fixing member not only on the side surface of the electrode stack, where volume change may occur, but also on the side surface of the current collector terminal, where volume change is sufficiently small compared to the electrode stack.

[0015] Furthermore, the present inventors have found that the above-described configuration can mitigate the concentration of local stress on the electrode stack due to the presence of a fixing member in the electrode stack. The reason for this is believed to be that by arranging fixing members only on the side surfaces of the electrode stack, rather than arranging fixing members on the upper, side, and lower surfaces of the electrode stack, it is possible to reduce the pressure applied at least in the stacking direction of the electrode stack.

[0016] The battery of the present disclosure may be, for example, a lithium-ion secondary battery. Examples of uses of the battery include power sources for vehicles such as hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), electric vehicles (BEVs), gasoline-powered vehicles, and diesel-powered vehicles. In particular, the battery is preferably used as a driving power source for hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), or electric vehicles (BEVs). The battery of the present disclosure may also be used as a power source for mobile objects other than vehicles (for example, trains, ships, and aircraft), or as a power source for electrical appliances such as information processing devices.

[0017] The battery of the present disclosure may be a liquid-based battery or a solid-state battery, and may particularly be a solid-state battery. In the context of the present disclosure, "solid-state battery" refers to a battery that uses at least a solid electrolyte as the electrolyte, and therefore a solid-state battery may use a combination of a solid electrolyte and a liquid electrolyte as the electrolyte. Alternatively, the solid-state battery of the present disclosure may be an all-solid-state battery, i.e., a battery that uses only a solid electrolyte as the electrolyte.

[0018] The elements that make up the battery of the present disclosure are described below.

[0019] <Electrode laminate> 1, a battery 1 of the present disclosure has an electrode stack 10. The electrode stack functions as the power generating element of the battery.

[0020] As illustrated in FIG. 1, the electrode stack 10 has a first side portion 10a, a second side portion 10b facing the first side portion, a third side portion 10c, and a fourth side portion 10d facing the third side portion.

[0021] In the present disclosure, the term "electrode stack" refers to a stack that constitutes a unit battery. Here, this "unit battery" may be composed of a stack of a positive electrode current collector layer, a positive electrode active material layer, an electrolyte layer (separator layer), a negative electrode active material layer, and a negative electrode current collector layer.

[0022] In the present disclosure, each layer constituting the electrode stack and a surface constituting a wide layered surface of the electrode stack are referred to as a "main surface," and a surface constituting the thickness between these main surfaces is referred to as a "side surface." Therefore, in the present disclosure, a "side surface portion" refers to a portion of the electrode stack that constitutes the side surface.

[0023] The shape of the electrode laminate is not particularly limited as long as it has the first to fourth side surface portions. For example, the shape of the main surface of the electrode laminate can be a quadrangle such as a square, rectangle, rhombus, or parallelogram. The shape of the main surface of the electrode laminate can also be a polygon other than a quadrangle. The shape of the side surface can be a quadrangle such as a square, rectangle, rhombus, trapezoid, or parallelogram.

[0024] In particular, as illustrated in Fig. 1, the shape of the main surface of the electrode stack may be rectangular, and the shape of the side surface may also be rectangular. That is, the electrode stack may be a rectangular parallelepiped. In this case, the fixing member described later may be disposed on the side surface defined by the long side of the electrode stack.

[0025] The size of the electrode laminate is not particularly limited and can be set appropriately according to the intended use of the battery, etc.

[0026] Hereinafter, each of the components that can constitute the electrode stack according to the present disclosure will be described.

[0027] To facilitate understanding of the present disclosure, the components of an electrode stack of a lithium ion secondary battery, which is a solid-state battery, will be described as an example, but the battery of the present disclosure is not limited to this.

[0028] (Positive electrode current collector layer) The conductive material used for the positive electrode current collector layer is not particularly limited, and may be, for example, SUS, aluminum, copper, nickel, iron, titanium, carbon, or the like.

[0029] The shape of the positive electrode current collector layer is not particularly limited, and examples thereof include foil, plate, mesh, etc. Among these, the foil shape is preferred.

[0030] The positive electrode current collector layer may extend from a side surface portion of the electrode stack on which no fixing member is arranged, i.e., either the first or second side surface portion, and a plurality of positive electrode current collector layers may be collected in the extending portion.

[0031] (Cathode active material layer) The positive electrode active material layer contains at least a positive electrode active material, and preferably further contains a solid electrolyte described below. In addition, depending on the intended use and purpose, it may contain additives used in positive electrode active material layers of solid-state batteries, such as a conductive additive or a binder.

[0032] The material of the positive electrode active material is not particularly limited. For example, the positive electrode active material may be lithium cobalt oxide (LiCoO2), lithium nickel oxide (LiNiO2), lithium manganese oxide (LiMn2O4), Li 1.5 Co 1 / 3 Ni 1 / 3 Mn 1 / 3 O2, LiCo 1 / 3 Ni 1 / 3 Mn 1 / 3 O2, Li 1+x Mn 2-x-y M y It may be a different element-substituted Li-Mn spinel having a composition represented by O4 (M is one or more metal elements selected from Al, Mg, Co, Fe, Ni, and Zn), or the like.

[0033] The conductive additive is not particularly limited, and may be, for example, a carbon material such as VGCF (Vapor Grown Carbon Fiber) or carbon nanofiber, or a metal material.

[0034] The binder is not particularly limited, and may be, for example, polyvinylidene fluoride (PVdF), carboxymethyl cellulose (CMC), butadiene rubber (BR), styrene butadiene rubber (SBR), or a combination thereof.

[0035] (solid electrolyte layer) The solid electrolyte layer includes at least a solid electrolyte. The solid electrolyte is not particularly limited, and any material that can be used as a solid electrolyte for a solid-state battery can be used. For example, the solid electrolyte may be a sulfide solid electrolyte, an oxide solid electrolyte, a polymer electrolyte, or the like.

[0036] Examples of sulfide solid electrolytes include, but are not limited to, amorphous sulfide solid electrolytes, crystalline sulfide solid electrolytes, and argyrodite-type solid electrolytes. Specific examples of sulfide solid electrolytes include Li2S-P2S5-based (Li7P3S 11 , Li3PS4, Li8P2S9, etc.), Li2S-SiS2, LiI-Li2S-SiS2, LiI-Li2S-P2S5, LiI-LiBr-Li2S-P2S5, Li2S-P2S5-GeS2(Li 13 GeP3S 16 , Li 10 GeP2S 12 ), LiI-Li2S-P2O5, LiI-Li3PO4-P2S5, Li 7-x PS 6-x Cl x etc.; or combinations thereof, but are not limited to these.

[0037] An example of an oxide solid electrolyte is Li7La3Zr2O 12、 Li 7-x La3Zr 1-x Nb x O 12、Li 7-3x La3Zr2Al x O 12 , Li 3x La 2 / 3-x TiO3, Li 1+x Al x Ti 2-x (PO4)3, Li 1+x Al x Ge 2-x (PO4)3, Li3PO4, Li 3+x PO 4-x N x (LiPON), etc., but are not limited to these.

[0038] Polymer electrolytes include, but are not limited to, polyethylene oxide (PEO), polypropylene oxide (PPO), and the like, and copolymers thereof.

[0039] The solid electrolyte may be glass or crystallized glass (glass ceramic). The solid electrolyte layer may contain, in addition to the solid electrolyte described above, a conductive additive, a binder, and the like, as needed. For the conductive additive and the binder, see the above description of the positive electrode active material layer.

[0040] (Negative electrode active material layer) The negative electrode active material layer contains at least a negative electrode active material, and preferably further contains the above-mentioned solid electrolyte. In addition, depending on the intended use and purpose, it may contain additives used in negative electrode active material layers of solid-state batteries, such as a conductive additive and a binder.

[0041] The material for the negative electrode active material is not particularly limited, but is preferably capable of absorbing and releasing metal ions such as lithium ions. For example, the negative electrode active material may be, but is not limited to, an oxide-based negative electrode active material, an alloy-based negative electrode active material, a carbon material, or the like.

[0042] The oxide-based negative electrode active material is not particularly limited, and examples thereof include lithium titanate (LTO) particles.

[0043] The alloy-based negative electrode active material is not particularly limited, and examples thereof include Si alloy-based negative electrode active materials and Sn alloy-based negative electrode active materials. Examples of Si alloy-based negative electrode active materials include silicon, silicon oxide, silicon carbide, silicon nitride, and solid solutions thereof. The Si alloy-based negative electrode active material can also contain elements other than silicon, such as Fe, Co, Sb, Bi, Pb, Ni, Cu, Zn, Ge, In, Sn, Ti, etc. The Sn alloy-based negative electrode active material can also contain tin, tin oxide, tin nitride, or solid solutions thereof. The Sn alloy-based negative electrode active material can also contain elements other than tin, such as Fe, Co, Sb, Bi, Pb, Ni, Cu, Zn, Ge, In, Ti, Si, etc.

[0044] The carbon material is not particularly limited, and examples thereof include hard carbon, soft carbon, graphite, and the like.

[0045] For the solid electrolyte used in the negative electrode active material layer, the above description regarding the solid electrolyte layer can be referred to, and for the conductive additive and binder, the above description regarding the positive electrode active material layer can be referred to.

[0046] (negative electrode current collector layer) The conductive material used for the negative electrode current collector layer is not particularly limited, and may be, for example, SUS, aluminum, copper, nickel, iron, titanium, carbon, or the like, but is not limited to these.

[0047] The shape of the negative electrode current collector layer is not particularly limited, and examples thereof include foil, plate, mesh, etc. Among these, foil is preferred.

[0048] The negative electrode current collector layer may extend from a side surface portion of the electrode stack on which no fixing member is arranged, i.e., from either the first or second side surface portion, and a plurality of negative electrode current collector layers may be collected in the extending portion.

[0049] <Collector terminal> 1, a battery 1 according to the present disclosure has a pair of current collecting terminals 20 disposed on first and second opposing side surfaces 10a, 10b of an electrode stack 10. The current collecting terminals may be electrically connected to the current collecting foils of the electrode stack. The pair of current collecting terminals may constitute a positive electrode current collecting terminal and a negative electrode current collecting terminal, respectively.

[0050] The shape of the current collecting terminal is not particularly limited as long as it has a side surface on which a fixing member (described later) can be disposed. Furthermore, when the battery of the present disclosure further includes a laminate film (described later), the shape of the current collecting terminal is not particularly limited as long as it can seal the electrode stack together with the laminate film.

[0051] The size of the current collecting terminal is not particularly limited. For example, the length of the side surface of the current collecting terminal is not particularly limited as long as it allows placement of the fixing member described below. The length of the surface of the current collecting terminal facing the first and second side surface portions of the electrode stack may be the same as or shorter than the length of the first and second side surface portions of the electrode stack.

[0052] In the present disclosure, the "side surface of the current collecting terminal" may be a surface of the current collecting terminal adjacent to the surface facing the first and second side surface portions of the electrode stack that is not parallel to the main surface of the electrode stack, i.e., a surface parallel to the direction in which the third and fourth side surface portions of the electrode stack extend.

[0053] The material of the current collecting terminal is not particularly limited as long as it has a current collecting function, and may be metal, particularly aluminum, stainless steel, or the like.

[0054] <Fixing member> 1 , the battery 1 of the present disclosure has a fixing member 30 that is disposed extending over the side surfaces of the pair of current collector terminals 20 and the opposing third and fourth side surfaces 10c, 10d of the electrode stack 10 between the pair of current collector terminals 20. This configuration makes it possible to make the fixing member less likely to peel off from the electrode stack, and to alleviate the concentration of local pressure on the electrode stack that is caused by the electrode stack having the fixing member.

[0055] The fixing member is not particularly limited as long as it can fix the electrode stack, and may be, for example, an adhesive tape, a plate-like member, or the like.

[0056] When the fixing member is adhesive tape, the thickness can be made thinner than when other members are used, thereby improving the volumetric efficiency of the battery.In addition, since adhesive tape is light, the weight of the battery can be reduced.

[0057] If the fixing member is a plate-like member or the like that does not have adhesive properties, adhesion or welding with an adhesive or the like is required to place the fixing member on the electrode laminate. However, if the fixing member is an adhesive tape, the fixing member can be easily placed on the electrode laminate.

[0058] That is, from the viewpoint of volumetric efficiency of the battery and productivity, the fixing member may be an adhesive tape.

[0059] The material of the adhesive tape is not particularly limited, but may be, for example, a stretchable material, particularly a polymer. By adopting such a configuration, even if a volume change occurs in the electrode laminate, the fixing member can follow the volume change, thereby making it even more difficult for the fixing member to peel off from the electrode laminate. Such an adhesive tape may particularly have a shrinkage amount greater than the volume change amount of the electrode laminate.

[0060] The shape and size of the fixing member are not particularly limited, but it is preferable that the fixing member does not extend from the side surfaces of the pair of current collecting terminals and the third and fourth side surfaces of the electrode stack.

[0061] <Laminating film> The battery of the present disclosure may further include a laminate film that seals the electrode stack together with the pair of collector terminals. Specifically, the laminate film may be formed by winding the electrode stack, the pair of collector terminals, and the fixing member, and sealing the electrode stack together with the collector terminals. The laminate film may also be composed of two films, and in this case, the two films may sandwich the electrode stack, the pair of collector terminals, and the fixing member from above and below in the stacking direction of the electrode stack, sealing the electrode stack together with the collector terminals.

[0062] The shape and size of the laminate film are not particularly limited as long as they can seal the electrode stack together with the current collecting terminals.

[0063] The laminate film may have a sealant resin layer, a metal layer, and a protective resin layer in this order along the thickness direction. Examples of materials for the sealant resin layer include olefin-based resins such as polypropylene (PP) and polyethylene (PE). Examples of materials for the metal layer include aluminum, aluminum alloys, and stainless steel. Examples of materials for the protective resin layer include polyethylene terephthalate (PET) and nylon.

[0064] The thickness of each layer constituting the laminate film and the laminate film itself are not particularly limited. The thickness of the sealant resin layer is, for example, 40 μm or more and 100 μm or less. The thickness of the metal layer is, for example, 30 μm or more and 60 μm or less. The thickness of the protective resin layer is, for example, 20 μm or more and 60 μm or less. The thickness of the laminate film is, for example, 80 μm or more and 250 μm or less. [Explanation of symbols]

[0065] 1 battery 10 Electrode laminate 10a First side portion 10b Second side portion 10c Third side part 10d Fourth side part 20 Current collector terminal 30 Fixing member

Claims

1. A battery having an electrode stack and a pair of current collecting terminals disposed on first and second opposing side surfaces of the electrode stack, a fixing member disposed to extend across the side surfaces of the pair of current collecting terminals and across the opposing third and fourth side surfaces of the electrode stack between the pair of current collecting terminals; A battery having

2. The battery according to claim 1 , wherein the fixing member is an adhesive tape.

3. The battery according to claim 1 or 2, further comprising a laminate film sealing the electrode stack together with the pair of current collecting terminals.

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