Cylindrical Cells and Battery Modules

Abstract

To provide a cylindrical battery capable of suppressing the generation of a short circuit in a manufacturing step.SOLUTION: A cylindrical battery comprises: a shaft center member; a winding electrode group 12 in which an electrode lamination body in which a positive electrode and a negative electrode are laminated via an electrolyte is wound around the shaft center member; an outer casing member 15 that winds the winding electrode group 12; a first lid member 16A that is arranged to one end part of a shaft center direction of the shaft center member, and is electrically connected to one of the positive electrode and the negative electrode; and an insulation member 17 that is arranged between the outer casing member 15 and the first lid member 16A. An outer diameter of the first lid member 16A is larger than an inner diameter of the outer casing member 15, and is smaller than an outer diameter of the outer casing member 15. The outer diameter of the insulation member 17 is larger than the outer diameter of the first lid member 16A. The insulation member 17 includes a first projection part 17a projected toward the winding electrode group 12 in an inner side of the winding electrode group 12 in a radial direction from an inner surface of the outer casing member 15.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a cylindrical battery and a battery module. [Background technology]

[0002] In recent years, research and development into secondary batteries that contribute to energy efficiency has been conducted to ensure that many people have access to affordable, reliable, sustainable and advanced energy.

[0003] Patent Document 1 describes a method for manufacturing a cylindrical nickel-metal hydride secondary battery. Specifically, a stepped insulating ring has an expanded-diameter upper portion and a reduced-diameter foot portion, and the reduced-diameter foot portion of the stepped insulating ring is positioned above the electrode plate assembly from the top opening of a bottomed cylindrical can containing an electrode plate assembly and an electrolyte. Furthermore, the peripheral portion of a lid member incorporating a safety valve is positioned on the stepped portion of the stepped insulating ring to form a sealing area where the inner wall of the top opening of the bottomed cylindrical can, the peripheral wall of the expanded-diameter upper portion of the stepped insulating ring, and the peripheral portion of the lid member face each other, and the sealing area is then crimped to form a sealed structure. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 9-134712 Summary of the Invention [Problem to be solved by the invention]

[0005] However, it is desirable to suppress the occurrence of short circuits during the manufacturing process.

[0006] An object of the present invention is to provide a cylindrical battery that can suppress the occurrence of short circuits during the manufacturing process. [Means for solving the problem]

[0007] One aspect of the present invention is a cylindrical battery comprising: an axial core member; a wound electrode group in which an electrode stack, in which positive electrodes and negative electrodes are stacked with an electrolyte interposed therebetween, is wound around the axial core member; an exterior member around which the wound electrode group is wound; a cover member disposed at one axial end of the axial core member and electrically connected to one of the positive electrodes and the negative electrodes; and an insulating member disposed between the exterior member and the cover member, wherein the outer diameter of the cover member is larger than the inner diameter of the exterior member but smaller than the outer diameter of the exterior member, the outer diameter of the insulating member is larger than the outer diameter of the cover member, and the insulating member has a protrusion that protrudes toward the wound electrode group, radially inward of the wound electrode group relative to the inner surface of the exterior member.

[0008] The axial member may have an insulating member arranged between the first conductive member and the second conductive member in the axial direction, and the insulating member may be fastened to the first conductive member and the second conductive member.

[0009] In the cylindrical battery, the space between the exterior member and the insulating member and the space between the lid member and the insulating member may be sealed with resin.

[0010] The insulating member may further include a second protruding portion protruding toward the opposite side of the exterior member, further outward in the radial direction of the wound electrode group than the cover member.

[0011] The insulating member may further have a through-hole penetrating a space between the insulating member and the exterior member and a space between the insulating member and the cover member.

[0012] The distance between the exterior member and the insulating member in the axial direction may be greater on the outside in the radial direction than on the inside in the radial direction.

[0013] The electrode stack may be formed by stacking the positive electrode and the negative electrode with a solid electrolyte layer interposed therebetween.

[0014] In another aspect of the present invention, a battery module includes a plurality of the above-described cylindrical batteries. [Effects of the Invention]

[0015] According to the present invention, it is possible to provide a cylindrical battery that can suppress the occurrence of short circuits during the manufacturing process. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a partially cutaway perspective cross-sectional view showing an example of a battery module according to an embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view showing the cylindrical battery of FIG. [Figure 3] FIG. 2 is a partial enlarged view of the area surrounded by the dashed line in the cylindrical battery of FIG. 1. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0018] Fig. 1 shows an example of a battery module of this embodiment. Fig. 2 shows the cylindrical battery of Fig. 1. Fig. 3 shows the area surrounded by the dashed line of the cylindrical battery of Fig. 1.

[0019] The battery module 100 includes a plurality of cylindrical batteries 10. Each cylindrical battery 10 includes an axial core member 11, a wound electrode group 12 formed by winding an electrode stack around the axial core member 11, the electrode stack including positive and negative electrodes stacked with an electrolyte interposed therebetween, a male screw portion 13A serving as a first fastening portion provided at one axial (upper) end of the axial core member 11, and a female screw portion 13B serving as a second fastening portion provided at the other axial (lower) end of the axial core member 11. In the battery module 100, adjacent cylindrical batteries 10 are connected via the male screw portion 13A and the female screw portion 13B.

[0020] In this case, the male screw portion 13A is molded integrally with the shaft core member 11. This improves the strength against the rotational torque when fastening the male screw portion 13A and the female screw portion 13B. The male screw portion 13A is electrically connected to one of the positive electrode and the negative electrode, and the female screw portion 13B is electrically connected to the other of the positive electrode and the negative electrode.

[0021] The first fastening portion may be a female thread portion, and the second fastening portion may be a male thread portion.

[0022] The axial member 11 has an insulating member 14 disposed between the first conductive member 11a and the second conductive member 11b in the axial direction, and the insulating member 14 is fastened to the first conductive member 11a and the second conductive member 11b. This compresses the insulating member 17, which will be described later, improving the sealing performance of the cylindrical battery 10. The first conductive member 11a has a female thread portion at its lower end in the axial direction. The insulating member 14 has a male thread portion at its upper end in the axial direction, and a female thread portion at its lower end in the axial direction. The second conductive member 11b has a male thread portion at its upper end in the axial direction.

[0023] The arrangement of the male and female threaded portions of the first conductive member 11a, the second conductive member 11b, and the insulating member 14 is not particularly limited as long as it is possible to fasten the first conductive member 11a, the second conductive member 11b, and the insulating member 14 together.

[0024] Additionally, second conductive member 11b may be molded integrally with second cover member 16B, which will be described later.

[0025] The material forming the first conductive member 11a and the second conductive member 11b is not particularly limited, but examples thereof include metal, etc. The material forming the insulating member 14 is not particularly limited, but examples thereof include resins such as polypropylene (PP), polyethylene (PE), polyethylene terephthalate (PET), polyphenylene sulfide (PPS), polytetrafluoroethylene (PTFE), and PFA.

[0026] The electrode laminate is in a sheet form, and each electrode has an electrode mixture layer formed on an electrode current collector. That is, the positive electrode has a positive electrode mixture layer formed on a positive electrode current collector, and the negative electrode has a negative electrode mixture layer formed on a negative electrode current collector. The electrolyte is not particularly limited, and may be contained in, for example, an electrolytic solution impregnated in a general resin porous membrane (separator), a gel electrolyte layer, a solid electrolyte layer, or the like.

[0027] The electrode laminate may have a plurality of positive electrodes and / or negative electrodes, as long as the positive electrodes and negative electrodes are stacked with the electrolyte interposed therebetween. Examples of the stack structure of an electrode laminate having a plurality of positive electrodes and / or negative electrodes include positive electrode / electrolyte / negative electrode / electrolyte / positive electrode. In this case, the electrode laminate can be produced by, for example, roll pressing.

[0028] The cylindrical battery 10 further includes a packaging member 15 that wraps around the wound electrode group 12. The packaging member 15 is sheet-shaped. The material that constitutes the packaging member 15 is not particularly limited as long as it is conductive, and examples thereof include metals.

[0029] In this case, exterior member 15 may be bonded with an adhesive to the end of wound electrode group 12 on the side not in contact with shaft member 11, or may be an electrode current collector extending from the end of wound electrode group 12 on the side not in contact with shaft member 11. This improves the volumetric energy density of battery module 100.

[0030] The wound electrode group 12 wound with the exterior member 15 is obtained by winding the electrode stack and the exterior member 15 around the axial core member 11 while applying a predetermined tension. At this time, the electrode stack and the exterior member 15 may be wound while pressing the axial core member 11 from the outside.

[0031] Cylindrical battery 10 further includes a first lid member 16A located at one (upper) end in the axial direction and electrically connected to one of the positive and negative electrodes, and a second lid member 16B located at the other (lower) end in the axial direction and electrically connected to the other of the positive and negative electrodes. First lid member 16A and second lid member 16B each have an inclined region that is inclined approximately symmetrically with respect to axial member 11 and have a conical outer shape. A ring-shaped insulating member 17 is disposed between exterior member 15 and first lid member 16A. First lid member 16A is electrically connected to male thread portion 13A, and second lid member 16B is electrically connected to female thread portion 13B and exterior member 15.

[0032] The outer diameter of first lid member 16A is larger than the inner diameter of exterior member 15 but smaller than the outer diameter of exterior member 15. The outer diameter of insulating member 17 is also larger than the outer diameter of first lid member 16A. Furthermore, insulating member 17 has first protrusion 17a that protrudes toward wound electrode group 12, further inward in the radial direction of wound electrode group 12 than the inner surface of exterior member 15. This prevents short circuits from occurring between exterior member 15 and first lid member 16A during the manufacturing process of cylindrical battery 10.

[0033] The space between exterior member 15 and insulating member 17 and the space between first lid member 16A and insulating member 17 are sealed with resin R. Examples of resin R include curable resins such as thermosetting resins and photocurable resins (e.g., ultraviolet curable resins). This allows insulating member 17 to be bonded between exterior member 15 and first lid member 16A. As a result, the occurrence of short circuits between exterior member 15 and first lid member 16A during the manufacturing process of cylindrical battery 10 is further suppressed.

[0034] Insulating member 17 further has second protruding portion 17b that protrudes toward the opposite side of exterior member 15, further outward in the radial direction of wound electrode group 12 than first cover member 16A. This makes it easier to hold resin R when sealing the space between first cover member 16A and insulating member 17 with resin R.

[0035] Insulating member 17 further has through-holes T that penetrate the space between it and exterior member 15 and the space between it and first cover member 16A. Therefore, by pouring resin R into the space between first cover member 16A and insulating member 17, the space between exterior member 15 and insulating member 17 and the space between first cover member 16A and insulating member 17 can be sealed with resin R.

[0036] The distance in the axial direction between exterior member 15 and insulating member 17 increases in a stepped manner from the inside to the outside in the radial direction of wound electrode group 12. Therefore, when sealing with resin R, a space can be secured between exterior member 15 and insulating member 17.

[0037] The axial distance between the outer casing member 15 and the insulating member 17 is not particularly limited as long as the radially outer side of the wound electrode group 12 is larger than the radially inner side of the wound electrode group 12, and may be, for example, linearly larger.

[0038] There are no particular limitations on the angle of inclination of the inclined regions of first cover member 16A and second cover member 16B relative to shaft member 11. The angle of inclination of the inclined region of first cover member 16A relative to shaft member 11 is determined by the height of extension portion 18A adjacent to the side of shaft member 11 of wound electrode group 12 and the width determined by the number of turns of wound electrode group 12. Furthermore, the inclined region of first cover member 16A has a volume that can accommodate extension portion 18A.

[0039] The material that makes up first lid member 16A and second lid member 16B is not particularly limited as long as it is conductive, and examples include metal, etc. The materials that make up first lid member 16A and second lid member 16B may be the same or different.

[0040] Furthermore, the insulating member 17 is compressed by the fastening force between the male screw portion 13A provided at the upper end in the axial direction of the axial core member 11 and the female screw portion 13B provided at the lower end in the axial direction of the axial core member 11, and as a result, the exterior member 15 and the first cover member 16A are fixed and sealed together. Meanwhile, the contact portion of the second cover member 16B with the exterior member 15 is joined by laser welding, and they are sealed and integrated together.

[0041] The material constituting the insulating member 17 is not particularly limited, but examples thereof include resins such as polypropylene (PP), polyethylene (PE), polyethylene terephthalate (PET), polyphenylene sulfide (PPS), polytetrafluoroethylene (PTFE), and PFA.

[0042] The positive electrode current collector has an extending portion 18A extending from one (upper) end in the axial direction of the wound electrode group 12, and the negative electrode current collector has an extending portion 18B extending from the other (lower) end in the axial direction of the wound electrode group 12. Here, extending portion 18A of the positive electrode current collector collects current to first cover member 16A, and extending portion 18B of the negative electrode current collector collects current to second cover member 16B.

[0043] In this case, the second lid member 16B, which is electrically connected to the extension portion 18B that collects current on the exterior member 15, has a larger inclination angle of the inclined region than the first lid member 16A, which is electrically connected to the extension portion 18A that collects current on the shaft center member 11. This makes it easier to connect adjacent cylindrical batteries 10 via the male thread portion 13A and the female thread portion 13B.

[0044] Hereinafter, a case will be described in which the cylindrical batteries constituting the battery module of this embodiment are all-solid-state lithium secondary batteries.

[0045] The positive electrode current collector is not particularly limited, but may be, for example, aluminum foil.

[0046] The positive electrode mixture layer contains a positive electrode active material, and may further contain a solid electrolyte, a conductive additive, a binder, and the like.

[0047] The positive electrode active material is not particularly limited as long as it can absorb and release lithium ions. For example, LiCoO2, Li(Ni 5 / 10 Co 2 / 10 Mn 3 / 10 )O 2、 Li(Ni) 6 / 10 Co 2 / 10 Mn 2 / 10 )O 2、 Li(Ni) 8 / 10 Co 1 / 10 Mn 1 / 10 )O 2、 Li(Ni) 0.8 Co 0.15 Al 0.05 )O 2、 Li(Ni) 1 / 6 Co 4 / 6 Mn 1 / 6 )O 2、 Li(Ni) 1 / 3 Co 1 / 3 Mn 1 / 3 )O 2、 Examples include LiCoO4, LiMn2O4, LiNiO2, LiFePO4, lithium sulfide, and sulfur.

[0048] The solid electrolyte constituting the solid electrolyte layer is not particularly limited as long as it is a material capable of conducting lithium ions, and examples thereof include oxide-based electrolytes, sulfide-based electrolytes, and molecular crystalline electrolytes in which the electrolyte is dissociated into crystalline bodies made of organic substances.

[0049] The negative electrode mixture layer contains a negative electrode active material, and may further contain a solid electrolyte, a conductive additive, a binder, and the like.

[0050] The negative electrode active material is not particularly limited as long as it is capable of absorbing and releasing lithium ions, and examples thereof include metallic lithium, lithium alloys, metal oxides, metal sulfides, metal nitrides, Si, SiO, carbon materials, etc. Examples of carbon materials include artificial graphite, natural graphite, hard carbon, soft carbon, etc.

[0051] The negative electrode current collector is not particularly limited, but examples thereof include copper foil.

[0052] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and the above-described embodiments may be modified as appropriate within the scope of the spirit of the present invention. [Explanation of symbols]

[0053] 10 Cylindrical battery 11 Shaft core member 11a First conductive member 11b Second conductive member 12-wound electrode group 13A male thread 13B female thread 14 Insulating material 15 Exterior materials 16A First cover member 16B Second cover member 17 Insulating material 17a 1st protrusion 17b Second protrusion 18A, 18B extension part 100 Battery Module R resin T through hole

Claims

1. a shaft core member; a wound electrode group in which an electrode stack, in which a positive electrode and a negative electrode are stacked with an electrolyte interposed therebetween, is wound around the shaft member; an exterior member around which the wound electrode group is wound; a cover member disposed at one end of the shaft member in the axial direction and electrically connected to one of the positive electrode and the negative electrode; an insulating member disposed between the exterior member and the lid member, an outer diameter of the cover member is larger than an inner diameter of the exterior member and smaller than an outer diameter of the exterior member; The insulating member has an outer diameter larger than the outer diameter of the cover member, The insulating member has a protrusion that protrudes toward the wound electrode group and is located radially inward of the wound electrode group relative to the inner surface of the exterior member.

2. the axial member has an insulating member disposed between the first conductive member and the second conductive member in the axial direction, The cylindrical battery according to claim 1 , wherein the insulating member is fastened to the first conductive member and the second conductive member.

3. The cylindrical battery according to claim 1 or 2, wherein a space between the exterior member and the insulating member and a space between the lid member and the insulating member are sealed with resin.

4. The cylindrical battery according to claim 3 , wherein the insulating member further has a second protruding portion protruding toward the opposite side of the exterior member, further outward in the radial direction of the wound electrode group than the cover member.

5. The cylindrical battery according to claim 3 or 4, wherein the insulating member further has a through-hole penetrating a space between the insulating member and the exterior member and a space between the insulating member and the lid member.

6. The cylindrical battery according to claim 3 , wherein the distance between the exterior member and the insulating member in the axial direction is greater on the outside in the radial direction than on the inside in the radial direction.

7. The cylindrical battery according to claim 1 , wherein the electrode stack is formed by stacking the positive electrode and the negative electrode with a solid electrolyte layer interposed therebetween.

8. A battery module comprising a plurality of cylindrical batteries according to claim 1 .

Images