WO2024225069A1 - 非水電解液電池 - Google Patents

非水電解液電池 Download PDF

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Publication number
WO2024225069A1
WO2024225069A1 PCT/JP2024/014761 JP2024014761W WO2024225069A1 WO 2024225069 A1 WO2024225069 A1 WO 2024225069A1 JP 2024014761 W JP2024014761 W JP 2024014761W WO 2024225069 A1 WO2024225069 A1 WO 2024225069A1
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Prior art keywords
separator
positive electrode
wound body
negative electrode
electrolyte battery
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English (en)
French (fr)
Japanese (ja)
Inventor
隼輝 山本
玲 花村
大輔 平田
紘一 本池
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FDK Corp
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FDK Corp
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    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

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  • the present invention relates to a non-aqueous electrolyte battery.
  • Nonaqueous electrolyte batteries such as lithium primary batteries and lithium ion secondary batteries have a high energy density and are used in many electronic devices.
  • lithium primary batteries have an extremely long storage life and can be stored for over 10 years at room temperature, so they are widely used as the main power source and memory backup power source for various meters.
  • One such non-aqueous electrolyte battery is known to have a structure (spiral structure) in which the negative and positive electrodes are stacked and wound with a separator between them. Because the opposing surface area of the positive and negative electrodes is large, batteries with a spiral structure are often used in applications where output characteristics are important, i.e., applications where large currents are used.
  • a microporous film made of polyethylene or polypropylene is generally used as the separator.
  • the separator if the battery is subjected to, for example, excessive shock, the microporous film may move and cause a short circuit. A short circuit may also occur when dendrites or active material break through the separator.
  • Patent Document 1 discloses a cylindrical nonaqueous electrolyte battery that includes a wound body in which a positive electrode and a negative electrode are stacked and wound with a separator interposed between them, and the separator includes a microporous film and a nonwoven fabric, and the nonwoven fabric is disposed so as to be in contact with the negative electrode.
  • the inclusion of a microporous film and a nonwoven fabric makes it less likely for a short circuit to occur compared to a battery that contains only a microporous film, and reliability can be increased to a certain extent.
  • the electrolyte can become depleted around the positive electrode at the end of the discharge. This can cause an uneven distribution of the electrolyte around the positive electrode, resulting in a decrease in discharge capacity.
  • the present invention was made in consideration of the above circumstances, and aims to provide a nonaqueous electrolyte battery that has little decrease in discharge capacity due to depletion of electrolyte around the positive electrode at the end of discharge.
  • a nonaqueous electrolyte battery comprising: a wound body in which a positive electrode and a negative electrode are wound in a stacked state with a separator interposed between them; and an exterior can for accommodating the wound body, wherein the separator includes a first separator and a second separator that is stacked on the first separator and has a higher electrolyte absorption rate than the first separator, and wherein the second separator protrudes outward beyond the first separator at least on one end of the wound body in an axial direction.
  • the present invention provides a nonaqueous electrolyte battery that has little decrease in discharge capacity due to depletion of electrolyte around the positive electrode at the end of discharge.
  • FIG. 1 is a schematic cross-sectional view showing a nonaqueous electrolyte battery according to one embodiment of the present invention.
  • FIG. 2 is an enlarged view of the wound body and its surroundings shown in FIG. 3A to 3C are schematic partial cross-sectional views showing how the end portion of the separator is folded and shaped.
  • FIG. 4 is an enlarged view of a wound body and its surrounding essential parts according to a modified example.
  • the depletion of electrolyte around the positive electrode at the end of discharge is likely to occur when the expanded positive electrode absorbs the electrolyte in the separator during high current discharge.
  • the electrolyte in the separator is depleted in this way, the electrolyte distribution in the separator tends to become uneven, and the discharge capacity is likely to decrease.
  • At least two or more separators with different liquid absorption speeds are placed between the positive and negative electrodes, and the second separator with a higher liquid absorption speed is made to protrude further than the first separator with a lower liquid absorption speed at at least one end in the axial direction of the wound body.
  • the configuration of the nonaqueous electrolyte battery is described in detail below.
  • Nonaqueous Electrolyte Battery a lithium primary battery will be described as an example of the nonaqueous electrolyte battery according to this embodiment.
  • FIG. 1 is a schematic cross-sectional view showing a nonaqueous electrolyte battery 1 according to one embodiment of the present invention.
  • FIG. 2 is an enlarged view of the wound body 3 and the surrounding essential parts shown in FIG. 1.
  • the nonaqueous electrolyte battery 1 includes an outer can 2, an electrode group (wound body) 3 housed within the outer can 2, an electrolyte 4, and a sealing body 5.
  • the outer can 2 is a metal battery case that houses the wound body 3.
  • the outer can 2 is a cylindrical battery case with a bottom and an opening.
  • the material of the outer can 2 can be iron, stainless steel, etc.
  • the sealing body 5 seals the opening of the outer can 2 and provides a positive electrode terminal.
  • the sealing body 5 includes a sealing plate 6, a positive electrode terminal 7, a metal washer 8, and a resin sealing gasket 9.
  • the sealing plate 6 is disk-shaped and has an opening in the center.
  • a metal positive electrode terminal 7 and a metal washer 8 are crimped to the opening of the sealing plate 6 via a resin sealing gasket 9.
  • the edge of the sealing plate 6 and the upper edge of the exterior can 2 are laser welded.
  • the wound body 3 is an electrode group including a positive electrode 10, a negative electrode 11, and a separator 12, and is housed in the exterior can 2.
  • the wound body 3 is, for example, a strip-shaped laminated sheet in which a separator 12, a positive electrode 10, a separator 12, a negative electrode 11, and a separator 12 are laminated, wound in the length direction so that the negative electrode 11 is on the outside.
  • the separator 12 includes a first separator 13 and a second separator 14 (see FIG. 2).
  • the positive electrode 10 of the wound body 3 is connected to the positive electrode terminal 7 via a positive electrode lead 15.
  • the negative electrode 11 arranged on the outermost surface of the wound body 3 is connected to the inner surface of the outer can 2 via a negative electrode lead 16.
  • the negative electrode 11 and the outer can 2, which is the negative electrode terminal are electrically connected to each other.
  • the nonaqueous electrolyte battery 1 further includes an upper insulating plate 17 and a lower insulating plate 18.
  • the upper insulating plate 17 is disposed between the wound body 3 and the sealing body 5.
  • the lower insulating plate 18 is disposed between the wound body 3 and the bottom of the outer can 2. This makes it possible to prevent an internal short circuit between the positive electrode 10 and the negative electrode 11.
  • the electrolyte solution 4 is sealed inside the outer can 2.
  • the electrolyte solution 4 is a solution in which an electrolyte is dissolved in an organic solvent.
  • the type of organic solvent is not particularly limited, and examples of the organic solvent that can be used include cyclic carbonates such as propylene carbonate (PC) and ethylene carbonate (EC), chain carbonates such as dimethyl carbonate (DMC) and diethyl carbonate (DEC), ethers such as 1,2-dimethoxyethane (DME), and lactones such as ⁇ -butyrolactone. These may be used alone or in combination of two or more types. For example, from the viewpoint of achieving a better balance between the dielectric constant and the viscosity, a cyclic carbonate and a chain carbonate may be used in combination.
  • cyclic carbonates such as propylene carbonate (PC) and ethylene carbonate (EC)
  • chain carbonates such as dimethyl carbonate (DMC) and diethyl carbonate (DEC)
  • ethers such as 1,2-dimethoxyethane (DME)
  • lactones such as ⁇ -butyrolactone
  • the electrolyte is a lithium salt, examples of which include lithium hexafluorophosphate (LiPF 6 ), lithium perchlorate (LiClO 4 ), lithium trifluoromethanesulfonate (LiCF 3 SO 3 ), LiN(CF 3 SO 2 ) 2 , LiN(C 2 F 5 SO 2 ) 2 , LiN(CF 3 SO 2 )(C 4 F 9 SO 2 ), and the like.
  • LiCF 3 SO 3 is preferred from the viewpoint of further improving the safety of the battery.
  • the concentration of the electrolyte in the electrolytic solution 4 is not particularly limited, but may be, for example, 0.1 to 5 mol%, preferably 0.25 to 3.5 mol%.
  • the wound body 3 includes a positive electrode 10, a negative electrode 11, and a separator 12.
  • the positive electrode 10 includes a positive electrode current collector and a positive electrode mixture layer.
  • the material of the positive electrode current collector may be any material that is corrosion resistant at the positive electrode potential, such as stainless steel or aluminum. Among these, stainless steel (SUS316, SUS444, etc.) is preferred. There are no particular restrictions on the shape of the positive electrode current collector, and it may be any of plain woven wire mesh, expanded metal, punched metal, metal foil, etc.
  • the positive electrode mixture layer is supported on the positive electrode current collector and includes a positive electrode active material and a conductive agent.
  • the positive electrode active material includes manganese dioxide, and may further include other active materials as necessary. Examples of the other active materials include graphite-based active materials such as graphite fluoride, metal oxides such as MoO 3 , V 2 O 5 , and Mn 2 O 4, and metal sulfides such as TiS 2 and MoS.
  • Examples of conductive agents include natural graphite, artificial graphite, carbon black, carbon fiber, etc.
  • the amount of conductive agent contained in the positive electrode mixture can be, for example, 1 to 10 parts by mass per 100 parts by mass of the positive electrode active material.
  • the positive electrode mixture may further contain a binder as necessary.
  • binders include fluororesins such as polytetrafluoroethylene (PTFE) and polyvinylidene fluoride (PVdF), and styrene butadiene rubber (SBR).
  • PTFE polytetrafluoroethylene
  • PVdF polyvinylidene fluoride
  • SBR styrene butadiene rubber
  • the amount of binder contained in the positive electrode mixture may be, for example, 1 to 10 parts by mass per 100 parts by mass of the positive electrode active material.
  • the thickness of the positive electrode 10 when the positive electrode mixture layers are disposed on both sides of the positive electrode current collector can be, for example, 100 to 800 ⁇ m, depending on the desired capacity. If the thickness of the positive electrode 10 is 100 ⁇ m or more, it is easier to further increase the discharge capacity, and if it is 800 ⁇ m or less, it is easier to further reduce the internal resistance value of the battery, since the diffusion distance of the Li ions in the positive electrode mixture can be further shortened.
  • the negative electrode 11 includes a negative electrode active material layer.
  • the negative electrode active material layer may be a sheet-shaped (foil-shaped) lithium metal or lithium alloy.
  • the lithium alloy include a lithium aluminum alloy (Li-Al), a lithium magnesium alloy (Li-Mg), a lithium tin alloy (Li-Sn), a lithium zinc alloy (Li-Zn), a lithium antimony alloy (Li-Sn), and a lithium silicon alloy (Li-Si, Li-Ni-Si).
  • the negative electrode active material layer may include a layer in which a metal foil (e.g., aluminum foil) that alloys with lithium is laminated on a lithium foil, and alloyed by an electrochemical reaction.
  • a metal foil e.g., aluminum foil
  • the alloying metal include magnesium, tin, zinc, silicon, etc.
  • the negative electrode 11 may further include a negative electrode current collector that supports a negative electrode active material layer.
  • the material of the negative electrode current collector may be any material that is corrosion resistant at the negative electrode potential, such as copper, nickel, stainless steel, etc.
  • the shape of the negative electrode current collector may be the same as that of the positive electrode current collector.
  • the separator 12 is disposed between the positive electrode 10 and the negative electrode 11 to electrically insulate them.
  • the separator 12 includes a first separator 13 and a second separator 14 (see FIG. 2).
  • the second separator 14 is a separator with a higher liquid absorption rate than the first separator 13. That is, the second separator 14 has a higher liquid absorption rate of the electrolyte than the first separator 13.
  • the second separator 14 may be disposed closer to the positive electrode 10 side than the first separator 13, or may be disposed closer to the negative electrode 11 side.
  • the depletion of the electrolyte in the separator at the end of discharge is likely to occur when the expanded positive electrode 10 absorbs the electrolyte in the separator due to the discharge of a large current. Therefore, as in this embodiment, it is preferable that the second separator 14, which has a higher liquid absorption rate, is disposed on the positive electrode 10 side (see FIG. 2).
  • the liquid absorption speed of the separator can be adjusted by the microstructure, average pore size, material, etc. For example, those with a microstructure that is prone to capillary action, such as nonwoven fabric, and those made of materials that have affinity with the electrolyte tend to have a high liquid absorption speed.
  • the difference in the liquid absorption speed between the second separator 14 and the first separator 13 is not particularly limited, but can be, for example, 0.5 cm/10 min or more.
  • the second separator 14 protrudes outward from the first separator 13 at least at one end in the axial direction of the wound body 3 (X direction in FIG. 1) (see FIG. 2). That is, at least at one end in the axial direction of the wound body 3, the end of the second separator 14 is located outward from the end of the first separator 13 in the axial direction. In this embodiment, the second separator 14 protrudes outward from the first separator 13 at one end in the axial direction of the wound body 3 (the can bottom side in FIG. 1).
  • the amount of protrusion L of the second separator 14 from the first separator 13 in the axial direction of the wound body 3 may be any amount that protrudes from the first separator 13, from the viewpoint of further suppressing poor electrolyte supply caused by compartmentalizing the electrode (positive electrode 10 in this embodiment) by the first separator 13 when bending and forming the end of the separator.
  • the amount of protrusion L depends on the battery size, but can be, for example, 0.1 mm or more and 5.0 mm or less, and more preferably 0.5 mm or more and 4.0 mm or less.
  • the width of the first separator 13 and the second separator 14 may be the same or different.
  • the width of the separator refers to the length in the direction perpendicular to the winding direction (length direction) of the separator, and means the length between one end and the other end of the separator in the axial direction.
  • the first separator 13 and the second separator 14 of the same width may be stacked with a mutual offset, or the first separator 13 and the second separator 14 having a larger width may be stacked. From the viewpoint of improving reliability and liquid absorption, it is preferable that the width of the second separator 14 is larger than the width of the first separator 13, as in this embodiment.
  • the first separator 13 and the second separator 14 are each made of resin, and their melting points may be the same or different. As described below, in order to prevent the electrode (positive electrode 10 in this embodiment) from being isolated due to welding between the second separator 14 on the inside of the winding and the second separator 14 on the outside of the winding when the axial ends of the first separator 13 and the second separator 14 are thermoformed, and to further suppress uneven distribution of the electrolyte, it is preferable that the melting point of the second separator 14 is higher than the melting point of the first separator 13.
  • the difference in melting point between the second separator 14 and the first separator 13 is preferably, for example, 20°C or more.
  • the greater the difference in melting point the less likely it is that the second separator 14 on the inside of the roll and the second separator 14 on the outside of the roll will be welded together when the axial ends of the first separator 13 and the second separator 14 are thermoformed, making it easier to ensure a gap for taking in the electrolyte.
  • the melting point of the separator can be measured by differential scanning calorimetry (DSC) as the temperature of the minimum endothermic peak when the temperature is raised from room temperature to 200°C at a rate of 10°C/min.
  • DSC differential scanning calorimetry
  • the first separator 13 may be a microporous film or a nonwoven fabric.
  • the first separator 13 is preferably a microporous film.
  • the material of the microporous film is not particularly limited, but examples thereof include olefin resins such as polyethylene and polypropylene, polyesters such as polyethylene terephthalate and polybutylene terephthalate, and thermoplastic resins such as polyphenylene sulfide and cellulose.
  • the microporous film may contain inorganic particles as necessary.
  • the liquid absorption speed of the first separator 13 is not particularly limited, but may be, for example, 0.05 cm/10 min or more and less than 0.2 cm/10 min.
  • the melting point of the first separator 13 is preferably lower than the melting point of the second separator 14, and is more preferably within the range of 120 ⁇ 25°C (95-145°C). This makes it easier to shut down at around 120°C, thereby improving reliability.
  • the thickness of the first separator 13 is not particularly limited, but may be, for example, 10 ⁇ m or more and 40 ⁇ m or less. If the thickness of the first separator 13 is 10 ⁇ m or more, the electrolyte retention can be further improved, and if it is 40 ⁇ m or less, the internal resistance of the battery can be further reduced.
  • the second separator 14 is laminated on the first separator 13.
  • the second separator 14 may be any separator having a higher liquid absorption rate than the first separator 13, and may be a microporous film or a nonwoven fabric.
  • the second separator 14 is preferably a nonwoven fabric from the viewpoint of exhibiting high liquid absorption due to capillary action.
  • the material of the nonwoven fabric is not particularly limited, and the same materials as those listed as the materials of the microporous film can be used.
  • the liquid absorption speed of the second separator 14 is not particularly limited, but is preferably 0.2 cm/10 min or more, and more preferably 0.5 cm/10 min or more.
  • the upper limit of the liquid absorption speed of the second separator 14 is not particularly limited, but can be, for example, 5.0 cm/10 min or less.
  • the melting point of the second separator 14 is preferably higher than that of the first separator 13.
  • preferred examples of materials for the second separator 14 include polypropylene.
  • Polypropylene (PP) has a melting point of 125 to 160°C for random copolymers of ethylene and the like, and 160 to 170°C for homopolymers.
  • the melting point of the second separator 14 is not limited to polypropylene (PP) and can be within the range of 165 ⁇ 20°C (145 to 185°C).
  • the thickness of the second separator 14 is not particularly limited, but may be, for example, 10 ⁇ m or more and 40 ⁇ m or less from the same viewpoint as the thickness of the first separator 13.
  • the non-aqueous electrolyte battery can be manufactured by any method.
  • the non-aqueous electrolyte battery can be manufactured through the steps of 1) preparing a wound body 3, and 2) filling an outer can 2 with the wound body 3 and the electrolyte 4, and sealing the opening of the outer can 2.
  • step 1) first, the positive electrode 10 and the negative electrode 11 are prepared.
  • the positive electrode 10 can be produced, for example, by the following procedure. First, a positive electrode active material is mixed with any additives (conductive agent and binder) to prepare a positive electrode mixture slurry. Next, the positive electrode mixture slurry is applied or filled onto a positive electrode current collector, and then dried and rolled as necessary, and cut to a specified size to obtain the positive electrode 10. A positive electrode lead 15 is welded to one end in the longitudinal direction of the resulting strip-shaped positive electrode 10.
  • the negative electrode 11 can be obtained, for example, by cutting a sheet of lithium metal or lithium alloy to a specified size.
  • a negative electrode lead 16 is welded to one end in the longitudinal direction of the resulting strip-shaped negative electrode 11.
  • the obtained positive electrode 10 and negative electrode 11 are stacked with a separator 12 interposed therebetween and wound to produce the wound body 3.
  • the separator 12, the positive electrode 10, the separator 12, and the negative electrode 11 are stacked in this order.
  • the separator 12 is stacked such that the first separator 13 is on the negative electrode 11 side and the second separator 14 is on the positive electrode 10 side.
  • This strip-shaped laminated sheet is then wound in the length direction with the negative electrode 11 on the outside to form the wound body 3.
  • the width of the second separator 14 is greater than the width of the first separator 13, so that the second separator 14 protrudes outward beyond the first separator 13 at one axial end of the wound body 3.
  • the first separator 13 and the second separator 14 may be pre-welded at a portion of the overlapping portion. This makes it difficult for the first separator 13 and the second separator 14 to shift positions relative to each other even if pressure is applied to the battery due to being dropped or crushed when the battery is made into a battery, thereby improving the reliability of the battery.
  • the welding method may be either ultrasonic welding or heat welding.
  • the separator 12 at at least one end of the wound body 3 in the axial direction may be folded.
  • Figures 3A to 3C are schematic partial cross-sectional views showing how the end of the separator 12 is folded and shaped. For ease of explanation, only one end of the wound body 3 is shown in the figures.
  • the ends of the first separator 13 and the second separator 14 in the wound state are heated by applying hot air from the outside (see Figures 3A and 3B).
  • the ends of the first separator 13 and the second separator 14 are folded inward (see Figure 3C).
  • the melting point of the second separator 14 is preferably higher than the melting point of the first separator 13.
  • the heating temperature by the hot air is preferably lower than the melting point of the second separator 14, for example, a temperature equal to or higher than the melting point of the first separator 13 (e.g., 120°C) and lower than the melting point of the second separator 14.
  • step 2 the obtained wound body 3 is housed in an outer can 2, and after the electrolyte is injected, the opening of the outer can 2 is sealed with a sealing member 5. In this manner, the nonaqueous electrolyte battery 1 can be obtained.
  • the second separator 14 protrudes outward from the first separator 13 at one end of the wound body 3 in the axial direction (the end on the can bottom side), but the present invention is not limited to this.
  • FIG. 4 is an enlarged view of the wound body and the surrounding essential parts according to a modified example.
  • the second separator 14 may protrude outward beyond the first separator 13 at each of one end and the other end in the axial direction of the wound body 3.
  • the amount of protrusion L of the second separator 14 from the first separator 13 may be the same at one end and the other end, or may be different.
  • the amount of protrusion L on the can bottom side may be greater than the amount of protrusion L on the sealing body 5 side.
  • the separator 12 is composed of two sheets, the first separator 13 and the second separator 14, but this is not limited to this and it may be composed of three or more sheets. In that case, it is preferable that at least one end in the axial direction of the wound body 3, among the three or more separators, the separator with the highest liquid absorption rate protrudes outward more than the other separators.
  • the protrusion amount L of the separator with the highest liquid absorption rate relative to the other separators may be the same as above.
  • the shape of the outer can 2 was cylindrical, but this is not limited thereto, and the shape may also be rectangular.
  • a lithium primary battery is shown as an example of a non-aqueous electrolyte battery, but the present invention is not limited to this and may be, for example, a lithium ion secondary battery.
  • the liquid absorption rate and melting point of the separator were measured using the following method.
  • the melting point of the separator was determined as a value measured by differential scanning calorimetry (DSC) as the minimum temperature of the endothermic peak when the temperature was raised from room temperature to 200° C. at a rate of 10° C./min.
  • DSC differential scanning calorimetry
  • Example 1 (1) Preparation of Positive Electrode Electrolytic manganese dioxide as a positive electrode active material, a carbon material (graphite) as a conductive agent, and a fluorine-based binder (PTFE) as a binder were mixed in a mass ratio of 90:5:5 to prepare a positive electrode mixture.
  • a carbon material graphite
  • PTFE fluorine-based binder
  • the prepared positive electrode mixture was filled into a wire mesh (made of stainless steel) as a positive electrode current collector, dried, rolled to a thickness of 0.4 mm using a roll press, and cut to the specified dimensions (width 38 mm, length 230 mm) to obtain a positive electrode.
  • the positive electrode mixture was peeled off from part of the positive electrode to expose the positive electrode current collector, and a positive electrode lead was welded to the exposed part.
  • the positive electrode and negative electrode prepared above were wound with a microporous film 1 (first separator, width 40 mm) shown in Table 1 and a nonwoven fabric 2 (second separator, width 42 mm) shown in Table 1 interposed therebetween as separators.
  • the microporous film 1/nonwoven fabric 2/positive electrode/nonwoven fabric 2/microporous film 1/negative electrode were laminated in this order and wound so that the microporous film 1 was on the negative electrode side and the nonwoven fabric 2 was on the positive electrode side.
  • a wound body was obtained in which the positive electrode and the negative electrode were laminated via the separator and the negative electrode was disposed on the outermost peripheral surface.
  • the nonwoven fabric 2 protruded 2 mm outward from the microporous film 1 at one end in the axial direction.
  • the end of the roll in the axial direction was heated to 120°C by applying hot air from the outside, and the end of the microporous film 1 and the end of the nonwoven fabric 2 were folded inward toward the inside of the roll.
  • a ring-shaped lower insulating plate was placed at the bottom of a bottomed cylindrical outer can, and then the prepared wound body was housed in the outer can such that the one end (the side from which the nonwoven fabric 2 protruded) faced the bottom of the can. Then, the positive electrode lead was welded to the underside of the positive electrode terminal, and the negative electrode lead of the negative electrode was welded to the inner surface of the outer can.
  • Example 2 In the above (3) preparation of the wound body, a cylindrical lithium primary battery was obtained in the same manner as in Example 1 except that before winding, a microporous film 1 (first separator, width 40 mm) and a nonwoven fabric 2 (second separator, width 42 mm) were overlapped and both widthwise ends of the overlapping portion were ultrasonically welded.
  • Example 3 A cylindrical lithium primary battery was obtained in the same manner as in Example 1, except that in the above (3) preparation of the wound body, the microporous film 1 (first separator, width 40 mm) was placed on the positive electrode side and the nonwoven fabric 2 (second separator, width 42 mm) was placed on the negative electrode side.
  • Example 1 A cylindrical lithium primary battery was obtained in the same manner as in Example 1, except that in the preparation of the wound body (3) above, only the nonwoven fabric 2 (second separator, width 42 mm) was used and the microporous film 1 (first separator, width 40 mm) was not used.
  • Example 2 A cylindrical lithium primary battery was obtained in the same manner as in Example 1, except that in the preparation of the wound body (3) above, only the microporous film 1 (first separator, width 40 mm) was used and the nonwoven fabric 2 (second separator, width 42 mm) was not used.
  • Example 3 A cylindrical lithium primary battery was obtained in the same manner as in Example 1, except that in the preparation of the wound body (3) above, nonwoven fabric 1/microporous film 2/positive electrode/microporous film 2/nonwoven fabric 1/negative electrode were laminated and wound so that the microporous film 2 (first separator, width 42 mm) was on the positive electrode side and the nonwoven fabric 1 (second separator, width 40 mm) was on the negative electrode side.
  • the microporous film 2 protruded 2 mm outward from the nonwoven fabric 1 at one end in the axial direction.
  • the batteries of Comparative Examples 1 and 2 which use only a microporous film (first separator) or a nonwoven fabric (second separator), not only have low discharge capacity, but are also prone to short circuits due to free fall, and are therefore unreliable.
  • the battery of Comparative Example 3 which uses both a microporous film (first separator) and a nonwoven fabric (second separator) and has the microporous film protruding beyond the nonwoven fabric at one axial end of the wound body (the end on the can bottom side), is less prone to short circuits due to free fall, but has a discharge capacity lower than 2400 mAh.
  • the batteries of Examples 1 to 3 which use a microporous film (first separator) in combination with a nonwoven fabric (second separator) and have the nonwoven fabric extend beyond the microporous film at one end of the axial direction of the wound body (the end on the can bottom side), show little short circuiting due to free fall and a large discharge capacity of 2400 mAh or more.
  • placing the nonwoven fabric on the positive electrode side increases the discharge capacity more than placing it on the negative electrode side (Compare Examples 2 and 3).
  • the present invention provides a nonaqueous electrolyte battery that has little decrease in discharge capacity due to depletion of electrolyte around the positive electrode at the end of discharge.

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PCT/JP2024/014761 2023-04-28 2024-04-12 非水電解液電池 Ceased WO2024225069A1 (ja)

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS59178862U (ja) * 1983-05-16 1984-11-29 三洋電機株式会社 渦巻型電池
JPH0412255U (https=) * 1990-05-21 1992-01-31
JPH0737594A (ja) * 1993-07-16 1995-02-07 Yuasa Corp リチウム電池
JP2007250414A (ja) * 2006-03-17 2007-09-27 Hitachi Maxell Ltd 筒形非水電解液電池
JP2015032379A (ja) * 2013-07-31 2015-02-16 株式会社ギャラキシー 電池のセパレータ

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS59178862U (ja) * 1983-05-16 1984-11-29 三洋電機株式会社 渦巻型電池
JPH0412255U (https=) * 1990-05-21 1992-01-31
JPH0737594A (ja) * 1993-07-16 1995-02-07 Yuasa Corp リチウム電池
JP2007250414A (ja) * 2006-03-17 2007-09-27 Hitachi Maxell Ltd 筒形非水電解液電池
JP2015032379A (ja) * 2013-07-31 2015-02-16 株式会社ギャラキシー 電池のセパレータ

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