Patent Application
20250112301
The present application claims the benefit of Japanese Application No. 2023-167758 titled “BATTERY” and filed on Sep. 28, 2023, the contents of which is incorporated by reference herein in its entirety.
The present disclosure relates to a battery.
Batteries are capable of extracting energy due to chemical change or the like as electric energy, and used for various applications. For example, batteries are used in mobile devices such as mobile phones, smart phones, and notebook computers.
Conventionally, a battery can (exterior body) of such a battery is formed from a metal plate by, for example, a drawing/ironing process (deep drawing process).
The present disclosure relates to a battery.
The battery as described in the Background section cannot sufficiently improve vibration resistance.
The present disclosure, in an embodiment, relates to providing a battery having further improved vibration resistance.
The battery of an embodiment of the present disclosure includes:
The battery of an embodiment of the present disclosure can provide a battery having further improved vibration resistance.
The present disclosure will be described in further detail according to an embodiment. It should be noted that the following description and examples for those skilled in the art to fully understand the present disclosure, and these are not intended to limit the present disclosure. That is, the present disclosure is not particularly limited to the preferred embodiments and the like described below, and can be appropriately modified. Note that, in consideration of the description of the main points or ease of understanding, the present disclosure may be explained by being divided into embodiments, examples, and the like, for convenience, but partial replacement and/or combination of configurations illustrated in different embodiments and the like are possible. In the description of such an embodiment, redundant description of substantially the same matters may be omitted, and only different points may be described. In particular, similar functions and effects made by similar configurations are sometimes not be sequentially mentioned for each embodiment.
Furthermore, in the description in the present specification, reference to a direction, an orientation, or the like is merely for convenience of description, and is not intended to limit the scope of the present disclosure unless otherwise explicitly described. For example, relative terms such as “Outer (or outer side, outer part, or outer peripheral)” and “Inner (or inner side, inner part, or inner peripheral)” and derived terms thereof should be understood to refer to directions described or illustrated. Similarly, “on” an element includes not only a case of being in contact with the upper surface of the element but also a case of not being in contact with the upper surface of the element. That is, “on” an element includes not only an upper position away from the element, that is, an upper position via another object on the element or an upper position spaced apart from the element, but also an immediately above position in contact with the element. In addition, the term “on” does not necessarily mean the upper side in the vertical direction. The term “on” merely indicates a relative positional relationship of certain elements. That is, unless otherwise explicitly described, the disclosure is not limited only to a specific direction, orientation, form, or the like. In addition, the same applies to terms such as “provided”, “arranged”, and “connected”, and derived terms thereof. Unless otherwise explicitly described, the terms are not limited to a direct mode, and may be a mode in which another element such as an intervening object is interposed.
The various numerical ranges mentioned in the present specification are intended to include the lower and upper limit numerical values themselves unless otherwise specified, for example, by “less than”. More specifically, for example, it is interpreted that a numerical range such as 0.24 to 0.72% includes the lower limit value 0.24% and also includes the upper limit value 0.72%.
The term “battery” in the present specification includes not only a so-called “secondary battery” but also a “primary battery”, which is capable of only discharging. That is, the “battery” in the present specification may be a “secondary battery”, which can be repeatedly charged and discharged, or a “primary battery”, which is substantially only discharged. The “secondary battery” is not excessively limited by its name, and for example, “power storage devices” and the like can also be included in the subject.
Hereinafter, the “battery” of an embodiment of the present disclosure will be described in detail. While the description is made with reference to the drawings as necessary, the contents shown in the drawings are only schematically and illustratively shown for understanding the present disclosure, and the appearance, the dimensional ratio, and the like can be different from the actual ones. For example, the characteristic portions in the embodiments of the present disclosure may be emphasized.
Hereinafter, for convenience of description, the battery of the present disclosure will be described by taking a secondary battery as an example.
The present disclosure relates to a battery (secondary battery) 1 according to a first embodiment. The battery of the first embodiment will be described with reference mainly to
In the present specification, the cylindrical shape means that a cylinder has a large ratio (aspect ratio) of the height to the equivalent circle diameter of the bottom surface (for example, an aspect ratio of 1 or more). Here, the equivalent circle diameter of a bottom surface refers to the diameter of a circle having an area equal to the area of the bottom surface.
As illustrated in
In the first embodiment, the battery 1 has further improved vibration resistance.
As illustrated in
As described above, since the inner diameter ratio [(φ2−φ1)/φ2] is 0.72% or less, the clearance between the inner diameter of the exterior body 20 and the outer surface of the battery element 10 does not largely differ between the first inner diameter φ1 and the second inner diameter φ2. In addition, since the inner diameter ratio [(φ2−φ1)/φ2] is 0.24% or more, the clearance between the inner diameter of the exterior body 20 and the outer surface of the battery element 10 is sufficiently small. As a result, the battery element 10 is hardly vibrated in the whole exterior body 20. Therefore, in the first embodiment, the battery 1 has further improved vibration resistance.
Furthermore, in the first embodiment, the battery 1 can have a reduced defective rate in battery production, as well as improved vibration resistance.
The inner diameter of the exterior body 20 decreases along the direction in which the battery element 10 is inserted from the second inner diameter φ2 side to the first inner diameter φ1 side in the exterior body 20. Therefore, in the production of the battery 1, the battery element 10 is easily smoothly inserted into the exterior body 20. Therefore, the defective rate can be reduced when the battery 1 is produced.
Therefore, in the first embodiment, the battery 1 can have both “improved vibration resistance” and “reduced defective rate in battery production” conflicting therewith.
The method for calculating the inner diameter ratio of the battery element 10 is as follows. The battery 1 as a finished product is disassembled. The first outer end surface 11 side of the battery element 10 of the battery 1 is opened, and the position of the second outer end surface 12 of the battery element 10 is marked on the inner side surface of the exterior body 20. The exterior body 20 is taken out. A probe of a three-dimensional measuring machine (“Three-dimensional measuring machine” manufactured by Mitutoyo Corporation) is inserted into the exterior body 20, which has been taken out. The inner diameter is measured at predetermined positions (at the position 4 mm distant from the first inner end surface 21 toward the second outer end surface 12 for the first inner diameter φ1; at the position 7 mm distant from the second outer end surface 12 of the battery element 10 toward the first outer end surface 11 for the second inner diameter φ2). The inner diameter ratio [(φ2−φ1)/φ2] is calculated from the obtained inner diameters (φ1 and φ2).
Such an inner diameter ratio of the exterior body 20 can be adjusted, for example, by processing in multiple stages (at least two stages) using punches having different diameters in deep drawing in the method for producing the battery 1. An example thereof will be described with reference to
The above description has been made on the basis of the inner diameter ratio, but the description can also be made on the basis of the inner diameter difference.
In a preferred mode, the difference between the first inner diameter φ1 and the second inner diameter φ2 (φ2−φ1) is 0.05 to 0.15 mm. The difference (φ2−φ1) is calculated from the first inner diameter of and the second inner diameter φ2 measured by the calculation method for the battery element 10. When the difference (φ2−φ1) is 0.05 mm or more, the clearance between the inner diameter of the exterior body 20 and the outer surface of the battery element 10 does not largely differ between the first inner diameter φ1 and the second inner diameter φ2. In addition, when the difference (φ2−φ1) is 0.15 mm or less, the clearance between the inner diameter of the exterior body 20 and the outer surface of the battery element 10 is sufficiently small. As a result, the battery element 10 is hardly vibrated in the whole exterior body 20.
In a preferred mode of the exterior body 20, the inner diameter on the side of the second outer end surface 12 is preferably larger than the inner diameter on the side of the first outer end surface 11 within the range where the inner diameter ratio [(φ2−φ1)/φ2] is 0.24 to 0.72%. In a sectional view parallel to the battery axis, for example, the exterior 11 body 20 has a sectional shape that has at least one shape selected from a group consisting of a curved shape and a linear shape in at least a part of the section. Specific examples of the sectional shape include a trumpet shape consisting of a curved shape. The inner diameter of the exterior body 20 may be partly constant along the battery axis. For example, as illustrated in
As illustrated in
The element fixing portion 17 is located on the outer surface of the battery element 10. The element fixing portion 17 has a lower end arranged within the 4 mm region from the first inner end surface 21 toward the second outer end surface 12, and an upper end arranged within the 7 mm region from the second outer end surface 12 toward the first outer end surface 11. When viewed from the direction perpendicular to the battery axis, the element fixing portion 17 is arranged at least at the end portion of the electrode constituting layer, and optionally goes around the outer periphery (side peripheral surface) of the battery element 10.
The element fixing portion 17 may swell in the exterior body 20 in the presence of an electrolytic solution to function as a spacer. That is, the element fixing portion 17 fills the clearance between the outer surface of the battery element 10 and the inner surface of the exterior body 20. As a result, the area in contact with the inner surface of the exterior body 20 increases. In addition, the element fixing portion 17 may swell to be viscous, increasing adhesion to the inner surface of the exterior body 20. Therefore, the battery element 10 is further fixed in the exterior body 20, and vibration resistance can be further improved.
Examples of the resin constituting the element fixing portion 17 include a polyurethane resin from the viewpoint of easily swelling in an electrolytic solution and easily having an increased viscosity due to swelling.
As described above, the battery 1 of the first embodiment includes a battery element 10, an exterior body 20 housing the battery element, and an electrolyte (not illustrated). Each member will be described below.
As illustrated in
The battery element 10 includes a current collector (a positive electrode current collector and a negative electrode current collector), an electrode member layer (a positive electrode material layer and a negative electrode material layer) laminated with the current collector, and an electrode current collector.
The positive electrode 13 includes at least a positive electrode material layer and a positive electrode current collector. In the positive electrode 13, the positive electrode material layer is provided on at least one surface of the positive electrode current collector. The positive electrode material layer contains a positive electrode active material as an electrode active material. For example, for each of a plurality of positive electrodes 13 in the electrode assembly 10, the positive electrode material layer may be provided on both surfaces of the positive electrode current collector, or may be provided only on one surface of the positive electrode current collector.
The negative electrode 14 includes at least a negative electrode material layer and a negative electrode current collector. In the negative electrode 14, the negative electrode material layer is provided on at least one surface of the negative electrode current collector. The negative electrode material layer contains a negative electrode active material as an electrode active material. For example, for each of a plurality of negative electrodes 14 in the electrode assembly 10, the negative electrode material layer may be provided on both surfaces of the negative electrode current collector, or may be provided only on one surface of the negative electrode current collector.
The electrode active materials contained in the positive electrode 13 and the negative electrode 14, that is, the positive electrode active material and the negative electrode active material are materials directly involved in transfer of electrons in the secondary battery, and are main materials of the positive and negative electrodes that are responsible for charge and discharge, that is, the battery reaction. More specifically, ions are brought into the electrolyte due to the “positive electrode active material contained in the positive electrode material layer” and the “negative electrode active material contained in the negative electrode material layer”, and the ions move between the positive electrode 13 and the negative electrode 14 to transfer electrons, and thus charge and discharge is performed. The positive electrode material layer and the negative electrode material layer may be layers particularly capable of occluding and releasing lithium ions. That is, the secondary battery 1 of the first embodiment may be a non-aqueous electrolyte secondary battery, in which lithium ions move between the positive electrode 13 and the negative electrode 14 through the non-aqueous electrolyte to charge and discharge the battery 1. When lithium ions are involved in charge and discharge, the secondary battery 1 of the first embodiment corresponds to a so-called “lithium ion battery”, and includes layers capable of occluding and releasing lithium ions as the positive electrode 13 and the negative electrode 14.
In view of a lithium ion battery, the positive electrode active material may be a material that contributes to occlusion and release of lithium ions. That is, the positive electrode layer may contain any one kind or two or more kinds among positive electrode materials capable of occluding and releasing lithium. From such a viewpoint, the positive electrode active material may be, for example, a lithium-containing compound. The lithium-containing compound is not particularly limited in its type, but may be, for example, a lithium-containing composite oxide, a lithium-containing phosphate compound, or the like. This is because a high energy density can be easily obtained.
The lithium-containing composite oxide is a generic name of oxides containing lithium and one or two or more of other elements (elements other than lithium) as constituent elements, and may have, for example, one of crystal structures such as a layered rock-salt type crystal structure and a spinel type crystal structure. The lithium-containing phosphate 21 compound is a generic name of phosphate compounds that contain lithium and one or two or more of other elements as constituent elements, and may have, for example, a crystal structure such as an olivine crystal structure. The kind of the other elements is not particularly limited as long as the element is any one or two or more of arbitrary elements. Among them, as the other elements, one or two or more of elements belonging to Groups 2 to 15 in the long-period periodic table is preferable. More specific examples of the other elements include nickel (Ni), cobalt (Co), manganese (Mn), and iron (Fe). This is because a high voltage can be easily obtained.
Examples of the lithium-containing composite oxide having a layered rock-salt type crystal structure include compounds each represented by the following formulae (1) to (3).
LiaMn(1-b-c)NibM11cO(2-d)Fe (1)
(M11 represents at least one of cobalt (Co), magnesium (Mg), aluminum (Al), boron (B), titanium (Ti), vanadium (V), chromium (Cr), iron (Fe), copper (Cu), zinc (Zn), zirconium (Zr), molybdenum (Mo), tin (Sn), calcium (Ca), strontium (Sr), and tungsten (W).
“a” to “e” satisfy 0.8≤a≤1.2, 0<b<0.5, 0≤c≤0.5, (b+c)<1, −0.1≤d≤0.2, and 0≤e≤0.1. However, the composition of lithium varies depending on the charged and discharged states, and “a” is a value of a fully discharged state).
LiaNi(1-b)M12bO(2-c)Fd (2)
(M12 is at least one of cobalt (Co), manganese (Mn), magnesium (Mg), aluminum (Al), boron (B), titanium (Ti), vanadium (V), chromium (Cr), iron (Fe), copper (Cu), zinc (Zn), molybdenum (Mo), tin (Sn), calcium (Ca), strontium (Sr), and tungsten (W); “a” to “d” satisfy 0.8≤a≤1.2, 0.005≤b≤0.5, −0.1≤c≤0.2, and 0≤d≤0.1. However, the composition of lithium varies depending on the charged and discharged states, and “a” is a value of a fully discharged state).
LiaCo(1-b)M13bO(2-c)Fd (3)
(M13 is at least one of nickel (Ni), manganese (Mn), magnesium (Mg), aluminum (Al), boron (B), titanium (Ti), vanadium (V), chromium (Cr), iron (Fe), copper (Cu), zinc (Zn), molybdenum (Mo), tin (Sn), calcium (Ca), strontium (Sr), and tungsten (W); “a” to “d” satisfy 0.8≤a≤1.2, 0≤b<0.5, −0.1≤c≤0.2, and 0≤d≤0.1. However, the composition of lithium varies depending on the charged and discharged states, and “a” is a value of a fully discharged state).
Specific examples of the lithium-containing composite oxide having a layered rock-salt type crystal structure include LiNiO2, LiCoO2, LiCO0.98Al0.01Mg0.01O2, LiNi0.5Co0.2Mn0.3O2, LiNi0.8Co0.15Al0.05O2, LiNi0.33Co0.33Mn0.33O2, Li1.2Mn0.52Co0.175Ni0.1O2, and Li1.15(Mn0.65Ni0.22Co0.13)O2.
When the lithium-containing composite oxide having a layered rock-salt type crystal structure contains nickel, cobalt, manganese, and aluminum as constituent elements, the atomic ratio of nickel is preferably 50 atomic % or more. This is because a high energy density can be easily obtained.
Examples of the lithium-containing composite oxide having a spinel type crystal structure include a compound represented by the following formula (4).
LiaMn(2-b)M14bOcFd (4)
(M14 is at least one of cobalt (Co), nickel (Ni), magnesium (Mg), aluminum (Al), boron (B), titanium (Ti), vanadium (V), chromium (Cr), iron (Fe), copper (Cu), zinc (Zn), molybdenum (Mo), tin (Sn), calcium (Ca), strontium (Sr), and tungsten (W); “a” to “d” satisfy 0.9≤a≤1.1, 0≤b≤0.6, 3.7≤c≤4.1, and 0≤d≤0.1. However, the composition of lithium varies depending on the charged and discharged states, and “a” is a value of a fully discharged state).
Specific examples of the lithium-containing composite oxide having a spinel type crystal structure include LiMn2O4.
Examples of the lithium-containing phosphate compound having an olivine type crystal structure include a compound represented by the following formula (5).
LiaM15PO4 (5)
(M15 is at least one of cobalt (Co), manganese (Mn), iron (Fe), nickel (Ni), magnesium (Mg), aluminum (Al), boron (B), titanium (Ti), vanadium (V), niobium (Nb), copper (Cu), zinc (Zn), molybdenum (Mo), calcium (Ca), strontium (Sr), tungsten (W), and zirconium (Zr). “a” satisfies 0.9≤a≤1.1. However, the composition of lithium varies depending on the charged and discharged states, and “a” is a value of a fully discharged state).
Specific examples of the lithium-containing phosphate compound having an olivine type crystal structure include LiFePO4, LiMnPO4, LiFe0.5Mn0.5PO4, and LiFe0.3Mn0.7PO4.
Incidentally, the lithium-containing composite oxide may be a compound represented by the following formula (6).
(Li2MnO3)x(LiMnO2)1-x (6)
(“x” satisfies 0≤x≤1. However, the composition of lithium varies depending on the charged and discharged states, and “x” is a value of a fully discharged state).
In addition, for example, the positive electrode material may be any one kind or two or more kinds among oxides, disulfides, chalcogenides, and conductive polymers. Examples of the oxide include titanium oxide, vanadium oxide, and manganese dioxide. Examples of the disulfide include titanium disulfide and molybdenum sulfide. The chalcogenide is, for example, niobium selenide or the like. The conductive polymer may be, for example, sulfur, polyaniline, polythiophene, or the like. However, the positive electrode material is not particularly limited, and may be a material other than the above materials.
The positive electrode material layer may contain a binder. Furthermore, the positive electrode material layer May contain a positive electrode conductive agent in order to facilitate electron transfer promoting the battery reaction. The positive electrode binder may contain, for example, any one or two or more types of synthetic rubbers and polymer compounds. The synthetic rubber is, for example, styrene-butadiene rubber, fluorine rubber, ethylene propylene diene, or the like. The polymer compound is, for example, polyvinylidene fluoride, polyimide, or the like. The positive electrode conductive agent includes, for example, any one or two or more of carbon materials. The carbon material may be, for example, graphite, carbon black, acetylene black, ketjen black, or the like. However, the positive electrode conductive agent may be a metal material, a conductive polymer, and the like, as long as it is a material exhibiting conductivity.
Similarly, the negative electrode active material of the negative electrode material layer may be a material that contributes to occlusion and release of lithium ions. That is, the negative electrode layer may contain any one kind or two or more kinds among negative electrode materials capable of occluding and releasing lithium. From such a viewpoint, the negative electrode active material may be, for example, various carbon materials, metal-based materials, and/or other materials.
When the carbon material is used as the negative electrode active material, the crystal structure shows a very small change when lithium is occluded and released, so that a high energy density can be easily and stably obtained. Further, the carbon material also functions as a negative electrode conductive agent, so that the negative electrode layer easily has an improved conductivity.
Specific examples of the carbon material include graphitizable carbon, non-graphitizable carbon, and/or graphite. More specifically, the carbon material may be, for example, pyrolytic carbons, cokes, glassy carbon fiber, organic polymer compound fired body, activated carbon, carbon blacks, or the like. The cokes may include pitch coke, needle coke, and petroleum coke. The organic polymer compound fired body is, for example, a material obtained by firing (carbonizing) a polymer compound such as phenol resin and furan resin at an appropriate temperature. In addition, the carbon material may be low crystalline carbon subjected to a heat treatment at a temperature of about 1000° C. or less, or may be amorphous carbon. The shape of the carbon material is not particularly limited, and may be at least one of a fibrous shape, a spherical shape, a granular shape, and a scaly shape.
The “metal-based material” used as the negative electrode active material is a generic term for materials containing any one kind or two or more kinds among metal elements and metalloid elements as constituent elements. When the metal-based material is used as the negative electrode active material, a high energy density can be easily obtained. The metal-based material may be a single metal, an alloy, a compound, two or more of these, or a material at least a part of which has one or two or more of these phases. However, the alloy includes a material containing one or more kinds of metal elements and one or more kinds of metalloid elements in addition to a material composed of two or more kinds of metal elements. The alloy may also contain a non-metallic element. The construction of this metal-based material may be, for example, a solid solution, a eutectic (eutectic mixture), an intermetallic compound, and a material in which two or more kinds among these coexist. The metal element and metalloid element described above may be, for example, any one kind or two or more kinds among metal elements and metalloid elements capable of forming an alloy with lithium. Specific examples of the metal element and the metalloid element include magnesium (Mg), boron (B), aluminum (Al), gallium (Ga), indium (In), silicon (Si), germanium (Ge), tin (Sn), lead (Pb), bismuth (Bi), cadmium (Cd), silver (Ag), zinc, hafnium (Hf), zirconium, yttrium (Y), palladium (Pd), and/or platinum (Pt). In a preferred embodiment, the metal element is silicon and tin. This is because the ability to occlude and release lithium is excellent and thus a higher energy density can be easily obtained. The material containing silicon as a constituent element may be a simple substance of silicon, an alloy of silicon, or a compound of silicon, may be two or more thereof, or may be a material at least a part of which has one or two or more of these phases. Similarly, the material containing tin as a constituent element may be a simple substance of tin, an alloy of tin, or a compound of tin, may be two or more thereof, or may be a material at least a part of which has one or two or more of these phases. The “simple substance” described here is a simple substance in a general sense to the utmost, and thus the simple substance May contain a small amount of impurities. That is, the purity of the single substance is not necessarily limited to 100%. The alloy of silicon contains, for example, any one or two or more of tin, nickel, copper, iron, cobalt, manganese, zinc, indium, silver, titanium, germanium, bismuth, antimony, chromium, and the like as constituent elements other than silicon. The compound of silicon contains, for example, any one or two or more of carbon, oxygen, and the like as constituent elements other than silicon. The compound of silicon may contain, for example, any one or two or more of a series of elements described in the alloy of silicon as constituent elements other than silicon. Specific examples of the alloy of silicon and the compound of silicon include SiB4, SiB6, MgSi, Ni2Si, TiSi2, MoSi2, CoSi2, NiSi2, CaSi2, CrSi2, Cu5Si, FeSi2, MnSi2, NbSi2, TaSi2, VSi2, WSi2, ZnSi2, SiC, Si3N4, Si2N2O, SiOv (0<v≤2), and/or LiSiO. In SiOv, “v” may be 0.2<v<1.4. The alloy of tin may contain, for example, any one or two or more types of silicon, nickel, copper, iron, cobalt, manganese, zinc, indium, silver, titanium, germanium, bismuth, antimony, chromium, and the like, as constituent elements other than tin. The compound of tin may contain, for example, any one or two or more types of carbon, oxygen, and the like, as constituent elements other than tin. The compound of tin may contain any one or two or more of a series of elements described in the alloy of tin, for example, as constituent elements other than tin. Specific examples of the alloy of tin and the compound of tin include SnOw (0<w≤2), SnSiO3, LiSnO, and/or Mg2Sn. Particularly, the material containing tin as a constituent element may be, for example, a material containing a second constituent element and a third constituent element together with tin, which is a first constituent element (tin-containing material). The second constituent element may be, for example, any one or two or more of cobalt, iron, magnesium, titanium, vanadium, chromium, manganese, nickel, copper, zinc, gallium, zirconium, niobium, molybdenum, silver, indium, cesium (Ce), hafnium (Hf), tantalum, tungsten, bismuth, silicon, or the like. The third constituent element may be, for example, any one or two or more of boron, carbon, aluminum, phosphorus, and the like. This is because a high battery capacity, excellent cycle characteristics, and the like can be easily obtained. Among these, the tin-containing material may be a material containing tin, cobalt, and carbon as constituent elements (tin cobalt carbon-containing material). This is because a high energy density can be easily obtained. In the tin cobalt carbon-containing material, at least a part of carbon as a constituent element may be bonded to a metal element or metalloid element as other constituent elements. This is because the aggregation of tin, crystallization of tin, and the like are easily suppressed. The tin cobalt carbon-containing material is not limited to a material that contains only tin, cobalt, and carbon as constituent elements (SnCoC). This tin cobalt carbon-containing material may further contain, for example, any one or two or more of silicon, iron, nickel, chromium, indium, niobium, germanium, titanium, molybdenum, aluminum, phosphorus, gallium, bismuth, and the like as a constituent element in addition to tin, cobalt, and carbon. In addition to the tin cobalt carbon-containing material, a material containing tin, cobalt, iron, and carbon as constituent elements (tin cobalt iron carbon-containing material) may be included.
In addition, the negative electrode material may be any one kind or two or more kinds among, for example, metal oxides and polymer compounds. Examples of the metal oxide include iron oxide, ruthenium oxide, and molybdenum oxide. Examples of the polymer compound include polyacetylene, polyaniline, and polypyrrole.
The negative electrode material layer may contain a binder. Furthermore, a negative electrode conductive agent may be included in the negative electrode material layer to facilitate the transfer of electrons promoting the battery reaction. The binder that can be contained in the negative electrode material layer is not particularly limited, and examples of the binder include at least one selected from the group consisting of styrene-butadiene rubber, polyacrylic acid, polyvinylidene fluoride, polyimide-based resins, and polyamideimide-based resins. The negative electrode conductive agent that can be contained in the negative electrode material layer is not particularly limited, but examples thereof include at least one selected from carbon blacks such as thermal black, furnace black, channel black, ketjen black, and acetylene black, graphite, carbon fibers such as carbon nanotube and vapor-grown carbon fiber, metal powders such as copper, nickel, aluminum, and silver, and polyphenylene derivatives. Note that the negative electrode material layer may contain a component derived from a thickener component (for example, a carboxymethyl cellulose) used during battery production.
The positive electrode current collector and the negative electrode current collector used in the positive electrode 13 and the negative electrode 14 are members that contribute to collecting and supplying electrons generated in the electrode active material due to the battery reaction. Such an electrode current collector may be a sheet-shaped metal member. The electrode current collector may have a single layer or multiple layers. Furthermore, the electrode current collector may have a porous or perforated form. For example, the current collector may be a metal foil, a punching metal, a net, an expanded metal, or the like. For example, the positive electrode current collector that is used for the positive electrode 13 may be made of a metal foil containing at least one selected from the group consisting of aluminum, nickel, stainless steel, and the like. Meanwhile, for example, the negative electrode current collector used for the negative electrode 14 may be made of a metal foil containing at least one selected from the group consisting of copper, aluminum, nickel, stainless steel, and the like.
The separator 15 used in the positive electrode 13 and the negative electrode 14 is a member provided from the viewpoint of preventing a short circuit due to contact between the positive electrode and the negative electrode and maintaining the electrolyte. In other words, the separator 15 is a member that isolates the positive electrode 13 and the negative electrode 14 from each other, and allows ions (for example, lithium ions) to pass therethrough while preventing a short circuit of current due to contact between both electrodes. For example, the separator 15 may be a porous or microporous insulating member, which may have a membrane form due to its small thickness.
The separator 15 may be, for example, any one or two or more of porous membranes such as synthetic resin and/or ceramic, and may be a laminated membrane of two or more porous membranes. The synthetic resin used for the separator 15 is, for example, polytetrafluoroethylene, polypropylene, polyethylene, and the like. For example, the separator May include a porous membrane (base material layer) and a polymer compound layer provided on one surface or both surfaces of the base material layer. Since the adhesion of the separator 15 to the positive electrode 13 can be improved and the adhesion of the separator 15 to the negative electrode 14 can be improved, the distortion of the wound electrode body is easily suppressed. The polymer compound layer contains, for example, any one or two or more types of polymer compounds such as polyvinylidene fluoride. Excellent physical strength and electrochemical stability can be easily obtained. For example, the polymer compound layer may contain any one or two or more types of insulating particles such as an inorganic particle. Examples of the kind of inorganic particles include aluminum oxide and/or aluminum nitride. In the first embodiment, the separator is not particularly limited by its name, and may be a solid electrolyte, a gel-like electrolyte, and/or an insulating inorganic particle having a similar function.
As the electrolyte, typically, the electrolytic solution contains a solvent and an electrolyte salt. The electrolytic solution may further contain any one or two or more of other materials such as additives. In a preferred mode, the separator may be impregnated with the electrolytic solution, and the positive electrode 13 and/or the negative electrode 14 may also be impregnated with the electrolytic solution.
The solvent may contain any one or two or more of non-aqueous solvents such as organic solvents. The electrolytic solution containing a non-aqueous solvent can be a so-called non-aqueous electrolytic solution. Examples of the non-aqueous solvent include a cyclic carbonate ester, a chain carbonate ester, a lactone, a chain carboxylate ester, and/or a nitrile (for example, mononitrile). This is because more excellent battery capacity, cycle characteristics, and/or storage characteristics can be easily obtained. Examples of the cyclic carbonate ester include ethylene carbonate, propylene carbonate, and/or butylene carbonate. Examples of the chain carbonate ester include dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, and/or methyl propyl carbonate. Examples of the lactone include γ-butyrolactone and/or γ-valerolactone. Examples of the chain carboxylate ester include methyl acetate, ethyl acetate, methyl propionate, ethyl propionate, methyl butyrate, methyl isobutyrate, methyl trimethylacetate, and/or ethyl trimethylacetate. Examples of the nitrile include acetonitrile, methoxyacetonitrile, and/or 3-methoxypropionitrile. Examples of the non-aqueous solvent include 1,2-dimethoxyethane, tetrahydrofuran, 2-methyltetrahydrofuran, tetrahydropyran, 1,3-dioxolane, 4-methyl-1,3-dioxolane, 1,3-dioxane, 1,4-dioxane, N,N-dimethylformamide, N-methylpyrrolidinone, N-methyloxazolidinone, N,N′-dimethylimidazolidinone, nitromethane, nitroethane, sulfolane, trimethyl phosphate, and/or dimethyl sulfoxide. In particular, the non-aqueous solvent preferably contains one or two or more of ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, and the like. This is because higher battery capacity, more excellent cycle characteristics, and/or more excellent storage characteristics can be easily obtained. In addition, examples of the non-aqueous solvent include an unsaturated cyclic carbonate ester, a halogenated carbonate ester, a sulfonate ester, an acid anhydride, a dicyano compound (dinitrile compound), a diisocyanate compound, a phosphate ester, and/or a chain compound having a carbon-carbon triple bond. This is because chemical stability of the electrolytic solution is easily improved. The “unsaturated cyclic carbonate ester” as used herein is a cyclic carbonate ester having one or two or more unsaturated bonds (carbon-carbon double bonds or carbon-carbon triple bonds). Examples of the unsaturated cyclic carbonate ester include vinylene carbonate, vinyl ethylene carbonate, and/or methylene ethylene carbonate. The “halogenated carbonate ester” is a cyclic or chain carbonate ester having one or two or more halogen elements as constituent elements. When the halogenated carbonate ester contains two or more halogens as a constituent element, the kind of the two or more halogens may be one kind or two or more kinds. Examples of the cyclic halogenated carbonate esters include 4-fluoro-1,3-dioxolan-2-one and/or 4,5-difluoro-1,3-dioxolan-2-one. Examples of the chain halogenated carbonate esters include fluoromethyl methyl carbonate, bis(fluoromethyl) carbonate, and/or difluoromethyl methyl carbonate. Examples of the sulfonate ester include a monosulfonate ester and/or a disulfonate ester. The monosulfonate ester may be a cyclic monosulfonate ester or a chain monosulfonate ester. Examples of the cyclic monosulfonate ester include sultones such as 1,3-propane sultone and/or 1,3-propene sultone. Examples of the chain monosulfonate ester include a compound in which a cyclic monosulfonate ester is cleaved in the middle. The disulfonate ester may be a cyclic disulfonate ester or a chain disulfonate ester. Examples of the acid anhydride include carboxylic anhydrides, disulfonic anhydrides, and/or carboxylic sulfonic anhydrides. Examples of the carboxylic anhydride include succinic anhydride, glutaric anhydride, and/or maleic anhydride. Examples of the disulfonic anhydride include ethanedisulfonic anhydride and/or propanedisulfonic anhydride. Examples of the carboxylic sulfonic anhydrides include anhydrous sulfobenzoic acid, anhydrous sulfopropionic acid, and/or anhydrous sulfobutyric acid. Examples of the dinitrile compound include a compound represented by NC—R1-CN (R1 is an alkylene group or an arylene group). Examples of the dinitrile compound include succinonitrile (NC—C2H4—CN), glutaronitrile (NC—C3H6—CN), adiponitrile (NC—C4H8—CN), and phthalonitrile (NC—C6H4—CN). Examples of the diisocyanate compound include a compound represented by OCN—R2-NCO (R2 is an alkylene group or an arylene group). Examples of the diisocyanate compound include hexamethylene diisocyanate (OCN—C6H12—NCO). Examples of the phosphate ester include trimethyl phosphate and triethyl phosphate. The chain compound having a carbon-carbon triple bond is a chain compound having one or two or more carbon-carbon triple bonds (—C≡C—). Examples of the chain compound having a carbon-carbon triple bond include propargyl methyl carbonate (CH≡C—CH2—O—C(═O)—O—CH3) and propargyl methyl sulfonate (CH≡C—CH2—O—S(═O)2—CH3).
For example, the electrolyte salt included in the electrolytic solution may include any one or two or more of salts such as a lithium salt. The electrolyte salt may contain a salt other than a lithium salt, for example. The salt other than lithium may be, for example, salts of light metals other than lithium. Examples of the lithium salts include lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium perchlorate (LiClO4), lithium hexafluoroarsenate (LiAsF6), lithium tetraphenylborate (LiB(C6H5)4), lithium methanesulfonate (LiCH3SO3), lithium trifluoromethane sulfonate (LiCF3SO3), lithium tetrachloroaluminate (LiAlCl4), dilithium hexafluorosilicate (Li2SiF6), lithium chloride (LiCl), and/or lithium bromide (LiBr). This is because more excellent battery capacity, cycle characteristics, and/or storage characteristics can be easily obtained. Among them, one or two or more of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, and lithium hexafluoroarsenate may be used.
A positive electrode lead 161 is connected to the end of the positive electrode 13 of the wound body and a negative electrode lead 162 is connected to the end of the negative electrode 14 of the wound body to take out a terminal outside the battery element 10.
The element fixing portion 17 is located on the side surface of the battery element 10 and fixes the end of the electrode constituting layer having a wound structure. Accordingly, the element fixing portion 17 prevents loosening or relaxing of the electrode constituting layer.
The exterior body (battery can) 20 corresponds to a member enclosing the electrode assembly 10 in which the electrode constituting layer including the positive electrode 13, the negative electrode 14, and the separator 15 is stacked. The battery can 20 may have, for example, a hollow structure in which one end portion is closed and the other end portion (open end portion) is opened. The battery can 20 is not particularly limited, but may be a metal can containing any one or two or more of metal materials such as iron, aluminum, stainless steel, and alloys thereof. For example, any one or two or more of metal materials such as nickel may be plated on the surface of the battery can.
The method for producing the battery 1 of the present disclosure will be exemplarily described with reference to the method for producing the battery 1 as an example. The battery 1 of the first embodiment can be produced, for example, by the following procedure.
For producing the positive electrode 13, the positive electrode active material is mixed as necessary with the positive electrode binder, the positive electrode conductive agent, and the like to obtain a positive electrode mixture. Next, the positive electrode mixture is dispersed in an organic solvent or the like to obtain a paste-like positive electrode mixture slurry. Then, the positive electrode mixture slurry is applied to one side or both sides of the positive electrode current collector, and the positive electrode mixture slurry is dried to form a positive electrode active material layer. Thereafter, if necessary, the positive electrode active material layer may be compression-molded using a roll press machine or the like. In such a case, the positive electrode active material layer may be heated, or may be repeatedly compression-molded two or more times. In the same manner, the negative electrode 14 can be produced. Specifically, the negative electrode active material, the negative electrode binder, the negative electrode conductive agent, and the like are mixed to obtain a negative electrode mixture. Subsequently, the negative electrode mixture is dispersed in an organic solvent or the like to obtain a paste-like negative electrode mixture slurry. Next, the negative electrode mixture slurry is applied to one side or both sides of the negative electrode current collector, and then the negative electrode mixture slurry is dried to form a negative electrode active material layer. Thereafter, if necessary, the negative electrode active material layer is compression-molded using a roll press machine or the like.
The metal plate is deep-drawn in multiple stages (at least two stages) to form the exterior body 20. For example, as illustrated in the upper view of
When the battery 1 is assembled, a positive electrode lead is connected to the positive electrode current collector by a welding method or the like, and a negative electrode lead is connected to the negative electrode current collector by a welding method or the like. Next, the positive electrode 13 and the negative electrode 14 are stacked with the separator 15 interposed therebetween, and then the positive electrode 13, the negative electrode 14, and the separator 15 are wound to form a wound electrode body. Next, the center pin is inserted into the winding space of the wound electrode body. Then, while the wound electrode body is sandwiched between a pair of insulating plates, the wound electrode body is housed inside the exterior body together with the pair of insulating plates. In this case, one end portion of the positive electrode lead is connected to the external terminal by a welding method or the like, and one end portion of the negative electrode lead is similarly connected to the exterior body 20 by a welding method or the like. Next, the electrolytic solution is injected into the exterior body 20, and the wound electrode body is impregnated with the electrolytic solution. Finally, one end of the exterior body 20 is sealed. Thus, the battery 1 is completed.
The battery of a second embodiment is different from the battery 1 of the first embodiment in terms of electrical connection with the battery element 10. In other words, the battery of the second embodiment is different from the battery 1 of the first embodiment in that the battery of the second embodiment does not have leads (positive electrode lead and negative electrode lead), but extends the current collector to take out a terminal with a current collecting plate to the outside of the battery element 10. Hereinafter, this different configuration will be described in further detail according to an embodiment. In the second embodiment, the same reference numerals as those of the first embodiment denote the same configurations as those of the first embodiment, and thus the description thereof will be generally omitted.
Hereinafter, the battery of the second embodiment will be described with reference to
In the battery 1A of the second embodiment, the battery element 10A further includes a negative electrode current collecting plate 181 and a positive electrode current collecting plate 182 as shown in
Focusing on the connection mode between the positive electrode current collecting plate 182 and the positive electrode current collector 131, a plurality of the positive electrode current collectors 131 are extended and bundled in the vicinity of the first outer end surface 11 of the battery element 10A as shown in
The extending portion 132 of the positive electrode current collector 131 forms a high density region 133 where the extending portions 132 are present at a high density. The current collecting plate (positive electrode current collecting plate 182 and negative electrode current collecting plate 181) is connected to the high density region 133 in a planar shape. That is, the extending portions 132 are bundled and electrically connected to the positive electrode current collecting plate 182. In the second embodiment, the positive electrode current collecting plate 182 constitutes the second outer end surface 12. In the battery 1 of the first embodiment, the lead has a linear structure and is linearly connected to the current collector at the end of the wound structure. Therefore, the battery 1A has a contact area larger than that of the battery 1 of the first embodiment, and can reduce the connection resistance.
Furthermore, since the wound body does not have a lead, the wound body has a structure closer to a perfect circle when viewed from the direction perpendicular to the battery axis. Therefore, the clearance between the inner side surface of the exterior body 20 and the outer peripheral surface of the battery element 10 is likely to be more uniform. As a result, the battery element 10 is easily fixed in the exterior body 20, and the vibration resistance is further improved.
In addition, the wound body has a structure closer to a perfect circle. Therefore, in the production of the battery 1A, the battery element 10 is more smoothly housed in the exterior body 20, and the defective rate is further reduced in battery production.
The battery of a third embodiment is different from the battery 1 of the first embodiment in the arrangement of the element fixing portion 17. Hereinafter, this different configuration will be mainly described. In the third embodiment, the same reference numerals as those of the first and second embodiments denote the same configurations as those of the first and second embodiments, and thus the description thereof will be generally omitted.
Hereinafter, the battery of the third embodiment will be described with reference to
In the battery element 10B of the battery 1B of the third embodiment, as shown in
Although the embodiments of the present disclosure have been described above, the above-described embodiments are merely examples. The present disclosure is not limited to the above-described embodiments, and can be modified in design. In addition, the configurations in the first, second, and third embodiments may be variously combined.
For example, in the second embodiment, both the positive electrode 13 and the negative electrode 14 of the battery element 10 are taken out to the outside of the battery element 10 through the extending portion of the current collector, but the present disclosure is not limited thereto. Only one of the positive electrode and the negative electrode may be taken out by the extending portion of the current collector. In this case, the electrode having no extending portion of the current collector can have a lead.
The battery of the present disclosure is described in further detail as follows according to an embodiment.
<1>
A battery including: a battery element having a first outer end surface and a second outer end surface; and an exterior body having a cylindrical shape, having a first inner end surface to face the first outer end surface, and housing the battery element,
The battery according to <1>, wherein a difference between the first inner diameter φ1 and the second inner diameter φ2 (φ2−φ1) is 0.05 to 0.15 mm.
<3>
The battery according to <1> or <2>, wherein the battery element further has an element fixing portion on an outer peripheral surface of the battery element, and
The battery according to any one of <1> to <3>, wherein the battery element has a current collector having an extending portion, an electrode member layer laminated with the current collector, and an electrode current collecting plate constituting the first outer end surface and the second outer end surface, and
The battery according to any one of <1> to <4>, wherein, in a sectional view parallel to a battery axis, the exterior body has a section that has at least one shape selected from a group consisting of a curved shape and a linear shape in at least a part of the section.
The present disclosure will be described in further detail including with reference to Examples according to an embodiment. The present disclosure is not limited at all by the following Examples.
Prepared was a secondary battery having the following specifications. The configuration of Example 1 is summarized in Table 1.
The embodiment in which the electrode assembly includes leads is described as “In-element current collection specification” in the column of “Tab structure specification” in Table 1.
The electrode assembly had a wound structure in which a plurality of sheets was wound, and the end portion of the wound structure was fixed with an element fixing tape (element fixing portion). The element fixing tape was not arranged at the position 4 mm distant from the bottom of the can (bottom of exterior body: first inner end surface) toward the second end surface. Such mode is described as “None” in the column of “Element fixing tape” in Table 1.
The vibration test was performed under normal temperature and normal pressure (23±2° C., 1 atm) in accordance with the UN38.3 standard.
The battery of Example 1, which was 10% thinner than the element system standard for battery elements, was fully discharged. Specifically, the battery was discharged to a constant voltage of 2.5 V at a temperature of 23±2° C. and a constant current of 4.0 A.
The electric resistance value (AC resistance value) of the discharged battery was measured using a battery tester (“Battery Tester 3561” manufactured by HIOKI E.E. CORPORATION, AC voltmeter) (the number of measurements n=1000). Specifically, an AC constant current having a measurement frequency of 1 kHz was applied, and the voltage value was measured. The internal resistance value of the battery was calculated from the obtained voltage value. The average value of a plurality of internal resistance values was calculated, and the obtained average value was defined as “Electric resistance value before applying vibration”.
Sweep type vibration was applied to the discharged battery. Specifically, the sweep was applied at a frequency of 7 Hz (minimum value)→200 Hz (maximum value)→7 Hz (minimum value) over 15 minutes. With the frequency change as one cycle, the cycle was performed 12 times for each of the three directions: XYZ axes (XYZ axes shown in
From the obtained electric resistance values before and after applying vibration, the increase rate of electric resistance value due to applied vibration was calculated using the equation represented by (1):
Based on the increase rate of electric resistance value, the vibration resistance of the battery of Example 1 was evaluated according to the following evaluation criteria. The evaluation results of the vibration resistance are summarized in Table 1.
A (Pass: Good): the increase rate of electric resistance value is less than 10%
B (Fail: Bad): the increase rate of electric resistance value is 10% or more
In the production of the battery of Example 1, the battery element was housed in a cylindrical exterior body having an opening on the first end surface side such that the first outer end surface was faced to the vertically lower side. The housed battery element was observed in an image. Then, it was determined whether or not the second end surface of the battery element protrudes from the first opening end of the exterior body. The protrusions were counted for the measurements of n=100,000. (2):
The equation represented by (2): Defective assembly rate (ppm)=(Number of protrusions/Number of measurements n)×106 was used to calculate the defective assembly rate (element insertion defective rate). Based on the defective assembly rate, the battery of Example 1 was evaluated for reduction in defective assembly in the following evaluation results. The evaluation results on reduction in defective assembly are summarized in Table 1.
A (Pass: Good): the defective assembly rate is less than 2500 ppm
B (Fail: Bad): the defective assembly rate is 2500 ppm or more
Test batteries were prepared in the same manner as in Example 1 except that the battery configuration was changed to the configuration shown in Table 1. Specifically, the inner diameter ratio was changed in Examples 2 to 5 and Comparative Examples 1 to 2.
In Example 4 and Comparative Example 1, the element fixing tape (battery element fixing portion) on the outer surface of the battery element was arranged at the position 4 mm distant from the bottom of the can (first inner end surface of exterior body) toward the second outer end surface. Such mode is described as “Present” in the column of “Element fixing tape” in Table 1.
In Example 5, a current collector specification without a lead in the electrode assembly was adopted. In the current collector specification, for each of the positive electrode and the negative electrode, the extending portions of the current collectors were bundled to form a high density region and electrically connected to the current collecting plate.
For the batteries of Examples 2 to 5 and Comparative Examples 1 to 2, the vibration test and the defective assembly rate were performed in the same manner as in Example 1. Table 1 shows the evaluation results.
As shown in Table 1, in the batteries of Examples 1 to 5, the first inner diameter of the exterior body was 0.24 to 0.72% smaller than the second inner diameter thereof. For the vibration test for the batteries of Examples 1 to 5, all the results were A (Pass).
On the other hand, as shown in Table 1, in the batteries of Comparative Examples 1 to 2, the first inner diameter of the exterior body was less than 0.24% or more than 0.72% smaller than the second inner diameter thereof. For the vibration test for the batteries of Comparative Examples 1 to 2, all the results were B (Fail).
From the above, it is apparent that the batteries of Examples 1 to 5 have further improved vibration resistance as compared with Comparative Examples 1 to 2.
Note that the effects and the like of the above Examples are merely an example. Therefore, the present disclosure is not limited to the above matters, and may have additional effects.
The battery according to the present disclosure (a battery such as a primary battery and a secondary battery) can be typically used for applications in which use of electric energy is required. For example, the (secondary) battery according to the present disclosure can be used in various fields in which power storage is assumed. Although it is merely an example, the (secondary) battery of the present disclosure can be used in the fields of electricity, information, and communication in which electric and electronic equipment and the like are used (for example, electric and electronic equipment fields or mobile equipment fields including mobile phones, smartphones, notebook computers and digital cameras, activity meters, arm computers, electronic papers, and wearable devices, and small electronic machines such as RFID tags, card type electronic money, and smartwatches), home and small industrial applications (for example, the fields of electric tools, golf carts, and home, nursing, and industrial robots), large industrial applications (for example, fields of forklift, elevator, and harbor crane), transportation system fields (for example, the fields of hybrid automobiles, electric automobiles, buses, trains, power-assisted bicycles, and electric two-wheeled vehicles), power system applications (for example, fields such as various types of power generation, road conditioners, smart grids, and household power storage systems), medical applications (medical equipment fields such as earphone hearing aids), pharmaceutical applications (fields such as dosage management systems), IoT fields, space and deep sea applications (for example, fields such as a space probe and a submersible), and the like.
It should be understood that various changes and modifications to the embodiments described herein will be apparent to those skilled in the art. Such changes and modifications can be made without departing from the spirit and scope of the present subject matter and without diminishing its intended advantages. It is therefore intended that such changes and modifications be covered by the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2023-167758 | Sep 2023 | JP | national |
