Battery

Abstract

To suppress the generation of a crease at a corner part of a junction part of an exterior package, and suppress the damage of the exterior package.SOLUTION: A battery accommodates an electrode body with a square shape in a plan view in an exterior package. The exterior package includes a concave part with a square shape in a plan view to accommodate the electrode body. A junction part is provided at the outer peripheral end part of the exterior package. At the corner part of the concave part, a projection extending to the junction part is provided.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a battery having an electrode assembly and an exterior body that seals the electrode assembly. [Background technology]

[0002] Patent Document 1 discloses a battery in which a rectangular electrode body is sealed with a laminate film (exterior body), and a spacer is disposed between the corners of the rectangular electrode body and the laminate film. It is described that this suppresses the occurrence of wrinkles concentrated in the laminate film, particularly at the corners, and prevents damage to the metal foil layer of the laminate film, thereby preventing deterioration of battery performance. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2004-39271 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, even when the spacers as described in Patent Document 1 are disposed, the phenomenon of wrinkles occurring at the corners has been confirmed, and damage to the laminate film has occurred.

[0005] In view of the above background technology, an object of the present disclosure is to prevent the occurrence of wrinkles at corners of joints of an exterior body and to prevent the occurrence of damage to the exterior body. [Means for solving the problem]

[0006] The present application discloses a battery in which an electrode body that is rectangular in plan view is housed in an outer casing, the outer casing having a recess that is rectangular in plan view for housing the electrode body, a joint at its outer peripheral edge, and protrusions at the corners of the recess that extend toward the joint.

[0007] The projection may be configured to form a cavity between the joint portion and the electrode assembly inside the exterior body. Effect of the Invention

[0008] According to the battery of the present disclosure, the strength of the corners of the recess can be increased, and excess exterior body that causes wrinkles can be absorbed, thereby suppressing damage to the exterior body. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is an external perspective view of an all-solid-state battery 10. [Diagram 2] FIG. 2(a) is a plan view of the all-solid-state battery 10, and FIG. 2(b) is an enlarged view of a portion of FIG. 2(a). [Diagram 3] FIG. 3(a) is a front view of the all-solid-state battery 10, and FIG. 3(b) is an enlarged view of a portion of FIG. 3(a). [Figure 4] FIG. 4(a) is a side view of the all-solid-state battery 10, and FIG. 4(b) is an enlarged view of a portion of FIG. 4(a). [Diagram 5] FIG. 5 is an exploded perspective view of the all-solid-state battery 10. [Figure 6] FIG. 6 is a cross-sectional view taken along line VI-VI. [Figure 7] FIG. 7 is a diagram for explaining the shape of the protrusion 15 according to another example. [Figure 8] FIG. 8 is a diagram for explaining the shape of the protrusion 15 according to another example. [Figure 9] FIG. 9 is a diagram illustrating another type of all-solid-state battery. [Figure 10] FIG. 10 is a diagram showing the results of the comparative example. [Figure 11] FIG. 11 shows the results of the example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] 1.Battery 1 to 6 show diagrams for explaining an all-solid-state battery 10 according to one embodiment. Here, an all-solid-state battery is described as a typical example, but the present disclosure is not necessarily applicable to an all-solid-state battery, and is applicable to a battery having an electrode body and an exterior body sealing the electrode body. FIG. 1 is an external perspective view, FIG. 2(a) is a plan view (viewed from the direction of arrow II in FIG. 1), FIG. 2(b) is an enlarged view of the part surrounded by the dotted line in FIG. 2(a), FIG. 3(a) is a front view (viewed from the direction indicated by arrow III in FIG. 1), FIG. 3(b) is an enlarged view of the part surrounded by the dotted line in FIG. 3(a), FIG. 4(a) is a side view (viewed from the direction indicated by arrow IV in FIG. 1), FIG. 4(b) is an enlarged view of the part surrounded by the dotted line in FIG. 4(a), and FIG. 5 is an exploded perspective view. FIG. 6 is a partial cross-section taken along the line indicated by VI-VI in FIG. 2(b).

[0011] 1 to 6, the all-solid-state battery 10 of this embodiment has an exterior body 11 (first exterior body 12, second exterior body 13) and an electrode body 14. The electrode body 14, which is generally rectangular in plan view, is contained in the exterior body 11, which is also generally rectangular in plan view. At this time, a positive electrode terminal 14a and a negative electrode terminal 14b extend from the electrode body 14 and are arranged so that their tips protrude from the exterior body 11. Each component and the relationship between them will be described below.

[0012] 1.1.Exterior body In this embodiment, exterior body 11 is made of a sheet-like member that is rectangular in plan view, and in this embodiment, it includes first exterior body 12 and second exterior body 13. Electrode body 14 is contained between first exterior body 12 and second exterior body 13, and the outer circumferential end of first exterior body 12 and the outer circumferential end of second exterior body 13 are joined to form joint portion 11a. Therefore, this exterior body 11 is bag-shaped, and contains and seals electrode body 14 inside.

[0013] First exterior body 12 is rectangular in plan view and has rectangular recess 12a in plan view (the opening of recess 12a is on the lower side of the paper in FIG. 5 and cannot be seen in a blind spot), and electrode body 14 is housed inside this recess 12a. Protruding portion 12b is provided on the outer periphery edge of recess 12a so as to protrude from said edge, and protruding portion 12b and the outer periphery end of the surface of second exterior body 13 are joined to form joint 11a.

[0014] Second exterior body 13 has a rectangular sheet shape in a plan view. As described above, the outer circumferential end of the surface of second exterior body 13 facing protruding portion 12b of first exterior body 12 is overlapped and joined to protruding portion 12b of first exterior body 12, forming joint portion 11a.

[0015] In this embodiment, the first exterior body 12 and the second exterior body 13 are composed of a laminate film. Here, the laminate film is a film having a metal layer and a sealant material layer. Examples of metals used in the laminate film include aluminum and stainless steel, and examples of materials used in the sealant material layer include thermoplastic resins such as polypropylene, polyethylene, polystyrene, and polyvinyl chloride. The method for joining the first exterior body 12 and the second exterior body 13, i.e., the method for joining the laminate film, is not particularly limited, and a known method can be used. Specific examples include a method of welding the sealant material layers of the laminate film together (for example, a hot plate welding method, an ultrasonic welding method, a vibration welding method, a laser welding method, or the like) and adhesion using an adhesive.

[0016] In this embodiment, the first exterior body 12 of the exterior body 11 has the following configuration. The first exterior body 12 is provided with protrusions 15 at the corners of the rectangular recess 12a in plan view at positions corresponding to the corners 10a of the all-solid-state battery 10. Therefore, in this embodiment, a total of four protrusions 15 are provided, one at each corner.

[0017] The protrusion 15 is a portion provided so as to be continuous with the recess 12a and protrude from the corner of the recess 12a, and is formed between the joint portion 11a and the recess 12a. In this embodiment, the protrusion 15 is in a so-called dome shape, and a cavity 15a surrounded by the protrusion 15, the second exterior body 13, and the electrode body 14 is formed as shown in FIG. 6 by the protrusion 15. As long as the cavity 15a is formed in such a shape, the specific shape of the protrusion 15 is not particularly limited. However, by forming the protrusion 15 between the joint portion 11a and the recess 12a at the corner of the recess 12a, the protrusion 15 can absorb the excess due to the gathering of the material that causes wrinkles in the exterior body 11, and suppress the generation of wrinkles.

[0018] The protrusion 15 preferably has a certain size in order to suppress the generation of wrinkles (absorb the excess due to the gathering of the material) at the corner of the recess 12a. That is, in this embodiment, the protrusion 15 protrudes from the recess 12a in each of the plan view shape (FIG. 2(b)) and the front view shape (FIG. 3(b)).

[0019] The height H of the protrusion 15 shown in FIGS. 3(b), 4(b), and 6 is at least H<T with respect to the thickness of the recess 12a indicated by T, preferably 0.2 times to 0.8 times, and more preferably 0.4 times to 0.6 times.

[0020] The protrusion of the protrusion 15 in the plan view (the protrusion indicated by L in FIGS. 2(b), 3(b), and 6) only needs to extend from the corner of the recess 12a toward the joint portion 11a. The direction is not particularly limited. In this embodiment, the protrusion 15 is configured to extend along the long axis of the all-solid-state battery 10 that is rectangular in the plan view. However, it is not limited to this. As shown in FIG. 7, the protrusion 15 may be configured to extend along the short axis of the all-solid-state battery 10 that is rectangular in the plan view, or as shown in FIG. 8, the protrusion 15 may extend along the diagonal line of the all-solid-state battery 10 that is rectangular in the plan view. Furthermore, it is not limited to this, and the protrusion 15 may be provided so as to extend in a direction between these. The protrusion amount of the protrusion 15 in plan view, indicated by L in Figures 2(b), 3(b), and 6, is preferably 1 mm or more, more preferably 2 mm or more, and further preferably 3 mm or more. There is no particular upper limit to L, but it is preferably 8 mm or less, and more preferably 5 mm or less.

[0021] The width W of the protrusion 15 in the plan view shown in Figure 2 (b) and Figure 4 (b) is preferably 1 mm or more, more preferably 2 mm or more, and further preferably 3 mm or more. There is no particular upper limit to L, but it is preferably 8 mm or less, and more preferably 5 mm or less.

[0022] As a more effective shape, it is preferable that the protrusion 15 has an inclined surface 15b that is inclined toward the joint 11a in the thickness direction (the stacking direction of each layer in the electrode body 14), as shown in Figures 3(b) and 6. The shape of the inclined surface 15b is not particularly limited, and may be a flat surface or a convex surface as shown in Figures 3(b) and 6. By making the inclined surface 15b a convex surface, it becomes easier to ensure the size of the cavity 15a.

[0023] Furthermore, it is preferable that the connection between the protrusion 15 and other parts (the recess 12a and the protrusion 12b) and the part where the direction of the protrusion 15 changes are connected by a curved surface. This can reduce stress concentration and further suppress the occurrence of breakage. In this case, the boundary between protrusion 15 and other parts may be unclear, but essentially protrusion 15 is a part that protrudes from a corner of exterior body 11 so as to extend toward joint 11a between first exterior body 12 and second exterior body 13. Although not particularly limited, for example, a part on the tip side of inflection point A shown in FIG. 6 may be protrusion 15.

[0024] 1.2. Electrode body The electrode body 14 has a positive electrode current collecting layer, a positive electrode composite layer, a separator layer, a negative electrode composite layer, a negative electrode current collecting layer, a positive electrode terminal 14a, and a negative electrode terminal 14b. In this embodiment, the positive electrode current collecting layer, the positive electrode composite layer, the separator layer, the negative electrode composite layer, the negative electrode current collecting layer, the negative electrode composite layer, the separator layer, the positive electrode composite layer, and the positive electrode current collecting layer are laminated in this order to form unit elements, and a plurality of these are laminated (sometimes referred to as "laminate 14c"). The positive electrode terminal 14a is electrically connected to the positive electrode current collecting layer of the laminate 14c, and the negative electrode terminal 14b is electrically connected to the negative electrode current collecting layer of the laminate 14c. The laminate 14c is also quadrangular in plan view.

[0025] 1.2a. Positive electrode current collecting layer The positive electrode current collecting layer is laminated on the positive electrode mixture layer to collect current from the positive electrode mixture layer. The positive electrode current collecting layer is a rectangular foil in plan view, and in this embodiment, is made up of a positive electrode current collecting foil, which is a metal foil, and a carbon layer laminated on the positive electrode current collecting foil. The carbon layer is laminated on the positive electrode mixture layer, thereby laminating the positive electrode current collecting layer on the positive electrode mixture layer. Examples of materials that can be used to form the positive electrode current collector foil include stainless steel, aluminum, nickel, iron, and titanium, and the carbon layer is made of a material that contains carbon.

[0026] 1.2b. Positive electrode composite layer The positive electrode mixture layer has the positive electrode current collecting layer on one surface and a separator layer on the other surface. The positive electrode mixture layer has a rectangular sheet shape in a plan view.

[0027] The positive electrode mixture layer is a layer containing a positive electrode active material, and may further contain at least one of a solid electrolyte material, a conductive material, and a binder, as necessary. The positive electrode active material may be a known active material. For example, cobalt-based (LiCoO2, etc.), nickel-based (LiNiO2, etc.), manganese-based (LiMn2O4, Li2Mn2O3, etc.), iron phosphate-based (LiFePO4, Li2FeP2O7, etc.), NCA-based (nickel, cobalt, aluminum compound), NMC-based (nickel, manganese, cobalt compound), etc. are listed. More specifically, LiNi 1 / 3 Co1 / 3 Mn 1 / 3 O2, etc. The surface of the positive electrode active material may be covered with an oxide layer such as a lithium niobate layer, a lithium titanate layer, or a lithium phosphate layer.

[0028] The solid electrolyte is preferably an inorganic solid electrolyte, since it has higher ionic conductivity and superior heat resistance compared to organic polymer electrolytes. Examples of inorganic solid electrolytes include sulfide solid electrolytes and oxide solid electrolytes. Examples of sulfide solid electrolyte materials having Li ion conductivity include Li2S-P2S5, Li2S-P2S5-LiI, Li2S-P2S5-Li2O, Li2S-P2S5-Li2O-LiI, Li2S-SiS2, Li2S-SiS2-LiI, Li2S-SiS2-LiBr, Li2S-SiS2-LiCl, Li2S-SiS2-B2S3-LiI, Li2S-SiS2-P2S5-LiI, Li2S-B2S3, and Li2S-P2S5-Z. m S n (where m and n are positive numbers. Z is Ge, Zn, or Ga.), Li2S-GeS2, Li2S-SiS2-Li3PO4, Li2S-SiS2-Li x MO y (wherein x and y are positive numbers; M is any of P, Si, Ge, B, Al, Ga, and In.) The above description of "Li2S-P2S5" means a sulfide solid electrolyte material obtained by using a raw material composition containing Li2S and P2S5, and the same applies to other descriptions.

[0029] On the other hand, examples of oxide solid electrolyte materials having Li ion conductivity include compounds having a NASICON structure. An example of a compound having a NASICON structure is a compound represented by the general formula Li 1+x Al x Ge 2-x Compounds represented by the formula (PO4)3 (0≦x≦2) (LAGP), general formula Li 1+x Al x Ti 2-x(PO4)3 (0≦x≦2) (LATP) and the like. Another example of the oxide solid electrolyte material is LiLaTiO (for example, Li 0.34 La 0.51 TiO3), LiPON (e.g., Li 2.9 PO 3.3 N 0.46 ), LiLaZrO (e.g., Li7La3Zr2O 12 ) etc.

[0030] The binder is not particularly limited as long as it is chemically and electrically stable, and examples thereof include fluorine-based binders such as polyvinylidene fluoride (PVDF) and polytetrafluoroethylene (PTFE), rubber-based binders such as styrene butadiene rubber (SBR), olefin-based binders such as polypropylene (PP) and polyethylene (PE), and cellulose-based binders such as carboxymethylcellulose (CMC). As the conductive material, carbon materials such as acetylene black (AB), ketjen black, and carbon fiber, and metal materials such as nickel, aluminum, and stainless steel can be used.

[0031] The content of each component in the positive electrode mixture layer may be the same as in the past. The thickness of the positive electrode mixture layer is, for example, preferably 0.1 μm to 1 mm, more preferably 1 μm to 150 μm.

[0032] 1.2c. Separator layer The separator layer (solid electrolyte layer) is a rectangular sheet-like layer in a plan view, and is disposed between the positive electrode composite layer and the negative electrode composite layer, and is a layer containing a solid electrolyte material. The separator layer contains at least a solid electrolyte material. The solid electrolyte material can be considered to be the same as the solid electrolyte material described for the positive electrode composite layer.

[0033] 1.2d.Negative electrode composite material layer The negative electrode mixture layer is a layer containing at least a negative electrode active material. The negative electrode mixture layer may contain a binder, a conductive material, and a solid electrolyte material as necessary. The binder, the conductive material, and the solid electrolyte material can be considered to be the same as those of the positive electrode mixture layer.

[0034] The negative electrode active material is not particularly limited. In the case of forming a lithium ion battery, examples of the negative electrode active material include carbon materials such as graphite and hard carbon, various oxides such as lithium titanate, Si and Si alloys, metallic lithium and lithium alloys, and the like.

[0035] The negative electrode mixture layer is in the form of a quadrangular sheet in plan view, with the separator layer laminated on one surface and the negative electrode current collecting layer laminated on the other surface. The content of each component in the negative electrode mixture layer may be the same as in the past. The thickness of the negative electrode mixture layer is, for example, preferably 0.1 μm to 1 mm, more preferably 1 μm to 150 μm.

[0036] 1.2e.Negative electrode current collecting layer The negative electrode current collecting layer is laminated on the negative electrode mixture layer to collect current from the negative electrode mixture layer. The negative electrode current collecting layer has a rectangular foil shape in a plan view, and can be made of, for example, stainless steel, copper, nickel, carbon, or the like.

[0037] 1.2f.Positive terminal, negative terminal The positive electrode terminal 14a and the negative electrode terminal 14b are made of conductive materials and serve as terminals for electrically connecting each electrode to the outside. One end of the positive electrode terminal 14a is electrically connected to the positive electrode current collecting layer, and the other end passes through the joint 11a between the first exterior body 12 and the second exterior body 13 and is exposed to the outside. One end of negative electrode terminal 14b is electrically connected to the negative electrode current collecting layer, and the other end passes through joint 11a between first exterior body 12 and second exterior body 13 and is exposed to the outside.

[0038] 2. Manufacturing The all-solid-state battery 10 can be produced by a known method. As described above, the electrode body 14 is placed inside the recess 12a of the first exterior body 12. Then, the first exterior body 12 and the second exterior body 13 are overlapped, and the protruding portion 12b of the first exterior body 12 is joined to the surface end portion of the second exterior body 13. At this time, a vacuum may be drawn to degas the inside of the recess 12a.

[0039] 3. Effects etc. According to the all-solid-state battery 10 of the present disclosure, the protrusions 15 provided on the exterior body 11 provided therein absorb excess caused by the biasing of the exterior body (laminate sheet), which is a cause of wrinkles, and suppress the occurrence of wrinkles that could become the starting point of cracks. As a result, the occurrence of cracks is suppressed, and the heat cycle resistance (resistance to cracks in the exterior body) is improved. Furthermore, the strength of the area where wrinkles are generated by the projections 15 can be improved, and from this viewpoint, the generation of cracks can also be suppressed. The exterior body (especially the laminate film) is vulnerable to heat cycles (repeated increases and decreases in temperature), and if wrinkles occur at the corners, stress is likely to concentrate there and cause cracks. The occurrence of cracks can cause damage to the exterior body and lead to battery deterioration. In contrast, the all-solid-state battery 10 makes it possible to suppress such defects. In conventional examples, wrinkles may occur during the production of an all-solid-state battery, or may occur during use or during a heat cycle test. However, according to the present disclosure, the occurrence of wrinkles can be suppressed in either case.

[0040] As described above, the protrusions may form cavities, and the protrusions may appear to be deformed, such as crushed, during the process of manufacturing the battery. However, as long as the protrusions potentially have the above-mentioned shape, they will be effective even in a deformed state. Therefore, whether the shape of the protrusions is within the scope of the present disclosure can be determined in either the state of the battery, the state before the electrode body is combined with the exterior body, or the state after the battery is disassembled and the electrode body is separated from the exterior body.

[0041] 4. Other Examples In addition to the above, an all-solid-state battery can be configured as shown in Fig. 9. Fig. 9 is a view corresponding to Fig. 6. In the example shown in Fig. 9, the second exterior body 13 is not used, and the exterior body is formed by overlapping two first exterior bodies 12. Therefore, the opening sides of the recesses 12a of the two first exterior bodies 12 and the protruding portions 12b are overlapped with each other, and the two protruding portions 12b become the joint portion 11a. In this embodiment, protrusions 15 are arranged at the corners of the electrode body 14 on both sides in the thickness direction of the electrode body 14 (the vertical direction of the paper, the stacking direction of each layer in the laminate 14c of the electrode body 14). Therefore, in this embodiment, the protrusions 15 are arranged so as to overlap each other, as shown in FIG. A battery of this type also provides the same effects as those described above.

[0042] In addition, in the above embodiment, the first outer casing 12 and the second outer casing 13 are joined together to form the electrode assembly. However, the present invention is not limited to this embodiment, and the electrode assembly may be formed by folding one outer casing member in half and sandwiching the electrode assembly therebetween, with the outer peripheral ends of three sides being joined together.

[0043] 5. Working Example 5.1. Electrode body configuration An electrode assembly was formed by a known method. The specifications of each layer of the electrode assembly were as follows: Positive electrode current collecting layer: Made of 1000 series aluminum, 10μm thick Positive electrode composite layer: NCM-based material, 50μm thick Separator layer: Material is sulfide solid electrolyte, thickness is 30μm Negative electrode composite layer: Material is lithium titanate, thickness is 50μm Negative electrode current collecting layer: Material is 1000 series aluminum, thickness is 10μm Electrode dimensions: 100mm x 200mm in plan view, total thickness 5mm

[0044] 5.2. Shape of the exterior body The exterior body is made of a processed laminate sheet, which consists of three layers: an insulating resin layer made of polyethylene terephthalate (PET), a metal layer made of aluminum, and a sealing resin layer (sealant material layer) made of polypropylene (PP), and is 0.15 mm thick. Its external dimensions are 120 mm × 220 mm in plan view, the external dimensions of the recess are 100 mm × 200 mm in plan view, the height of the recess (T in Figure 3(b)) is 5 mm, and the edge is a curved edge removal shape, with a so-called R of 1 mm. The protrusion has a height (H in Fig. 3(b)) of 2.5 mm, a protrusion amount (L in Fig. 3(b)) of 3 mm, and a width (W in Fig. 2(b)) of 3 mm.

[0045] 5.3. Fabrication of all-solid-state batteries In the embodiment, the electrode body was sealed in an exterior body having the above-mentioned protrusions. In the comparative example, the electrode body was sealed in an exterior body that did not have any protrusions.

[0046] 5.4. Test Method A heat cycle test was conducted on the fabricated all-solid-state battery. Specifically, the designated temperature on the high-temperature side was 100°C and the designated temperature on the low-temperature side was -20°C, with each cycle lasting 30 minutes, and this was repeated 2000 times. The fabricated all-solid-state battery was placed in a thermostatic chamber with high and low temperature air layers interchanged, and the layers were allowed to reach the designated temperature in about 10 minutes. The test was conducted so that the temperature of the all-solid-state battery remained at the designated temperature for at least 5 minutes.

[0047] 5.5.Results As a result of the test, in the comparative example, wrinkles occurred at the corners of the exterior body during production as shown in Figure 10, and cracks occurred in the exterior body after 300 cycles in the heat cycle test. In contrast, in the example, no wrinkles occurred as shown in Figure 11, and no cracks occurred even after 2000 cycles in the heat cycle test. [Explanation of symbols]

[0048] 10 All-solid-state battery 11 Exterior body 14 Electrode body 15 Protrusions

Claims

1. A battery in which an electrode assembly that is rectangular in plan view is housed in an exterior body, The exterior body has a recess that is rectangular in plan view and that houses the electrode body, and is provided with a joint portion at an outer peripheral end portion thereof, A corner of the recess has a protrusion extending toward the joint. battery.

2. The battery according to claim 1 , wherein the protrusion forms a cavity between the joint portion and the electrode body inside the exterior body.

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