JP6178962B1 - Laminated battery - Google Patents

Abstract

In a laminated battery including an electrode in which a positive electrode and a negative electrode are laminated and a conductive current collector penetrating the electrode, the contact between the electrode and the current collector is problematic due to its structure. Become. As a means for solving this problem, for example, welding an electrode and a current collector requires a great deal of labor. A first electrode that is one of a positive electrode and a negative electrode is not in contact with the current collector, and a second electrode that is either the positive electrode or the negative electrode is a current collector. By arranging a split plate spring that is a conductive elastic body between the current collector and the second electrode and has a curvature different from that of the current collector, the electrode and the current collector Provided is a laminated battery that eliminates the poor contact. [Selection] Figure 2

Description

  The present invention relates to a laminated battery, and more particularly to a laminated battery with improved current collecting performance.

  There are two types of secondary battery main electrode structures: a wound type and a stacked type. A battery having a wound-type electrode structure (a wound battery; for example, Patent Document 1) is housed in a battery case in a state in which a positive electrode and a negative electrode are wound in a spiral shape with a separator interposed therebetween. In a battery (laminated battery) having a stacked electrode structure, an electrode group in which positive electrodes and negative electrodes are alternately stacked via separators is housed in a battery case. Patent Document 2 discloses a cylindrical battery in which disk-shaped electrodes are stacked. Patent Document 3 discloses a rectangular battery in which rectangular plate electrodes are stacked and folded into a pleat shape.

  The laminated battery disclosed in Patent Document 4 includes an exterior body, a positive electrode, a negative electrode, a separator disposed between the positive electrode and the negative electrode, and a positive electrode, a negative electrode, and a separator that penetrate the axial direction of the exterior body. A conductive current collector. The positive electrode, the negative electrode, and the separator are laminated in the axial direction of the outer package. The first electrode which is one of the positive electrode and the negative electrode is in contact with the inner surface of the exterior body, but is not in contact with the current collector. The second electrode, which is the other electrode, is not in contact with the exterior body, but is in contact with the current collector. The outer edge of the second electrode is covered with a separator, and the peripheral edge of the hole through which the current collector of the first electrode passes is covered with the separator.

  In Patent Document 5, a positive electrode and a negative electrode are laminated in the axial direction of a cylindrical outer package, and a metal foil is interposed between one electrode of the positive electrode or the negative electrode and the outer package, and the other electrode of the positive electrode or the negative electrode A laminated battery in which a metal foil is interposed between a current collector and the current collector is disclosed.

JP 2002-198044 A JP 2000-48854 A International Publication No. 2009/125544 International Publication No. 2013/094383 JP 2014-71972 A

  When the battery active material is charged, its volume increases, and when it is discharged, its volume decreases. Therefore, the volume of the electrode changes due to charging / discharging. The volume of the electrode also varies depending on the temperature change. If the volume of the electrode changes, the gap between the electrode and the current collector changes, resulting in poor contact. If the electrode and the current collector are joined by spot welding, contact failure can be eliminated. However, spot welding of a large number of locations requires a lot of labor and time, and there is a problem that the manufacturing cost increases.

  In the laminated battery, due to its structure, short-circuit between electrodes and poor contact between the electrode and the current collector are problematic. In the laminated battery described in Patent Document 4, a current collector rod (hereinafter, referred to as a current collector) passes through the center of the disk-shaped electrode laminated in the axial direction of the battery, and the peripheral edge of the electrode hole and the current collector. One electrode is collected by contact with the body. On the other hand, current collection of the other electrode is attempted by contact between the outer edge of the electrode and the outer package. Since the diameter of the hole of the electrode through which the current collector passes is smaller than the outer diameter of the electrode, the contact portion between the electrode and the current collector is smaller than that of the exterior body. For this reason, the current collector is harder to collect than the exterior body, and in order to make contact with the current collector over the entire periphery of the hole of the electrode, it is necessary to increase the processing accuracy and assembly accuracy of the electrode and current collector. There is.

  As means for solving this problem, for example, Patent Document 5 discloses means for eliminating a contact failure by arranging a metal foil between an electrode and a current collector. However, disposing a metal foil between the electrode and the current collector has a problem of increasing the manufacturing cost.

  In a battery pack configured using a plurality of battery packs, if contact failure occurs in some of the battery packs, the predetermined performance of the battery pack cannot be exhibited, and the performance of the battery pack as a whole decreases. It will be. Moreover, it takes a lot of labor and labor to replace a laminated battery that has caused poor contact.

  In order to achieve the above-described object, a multilayer battery according to the present invention is a multilayer battery including a positive electrode, a negative electrode, and a conductive current collector that passes through the positive electrode and the negative electrode. The positive electrode and the negative electrode are stacked along the axial direction of the multilayer battery, and the first electrode that is one of the positive electrode and the negative electrode is not in contact with the current collector, The second electrode, which is the other of the positive electrode and the negative electrode, is electrically connected to the current collector, and is a conductive plate that is interposed between the current collector and the second electrode. A split plate spring having a long side extending along the axial direction of the current collector and a short side having an inner curvature different from the curvature of the current collector.

  According to this configuration, due to the action of the split plate spring interposed between the current collector and the second electrode, each of the plurality of second electrodes stacked with the current collector is interposed via the conductive split plate spring. Therefore, the connection is ensured with a small electric resistance.

  In the laminated battery according to the present invention, the inner curvature of the split plate spring is smaller than the curvature of the current collector. In the laminated battery according to the present invention, the inner peripheral length on the short side is ½ or less of the outer peripheral length of the current collector.

  In the laminated battery according to the present invention, the number of the split plate springs is 1 to 3. In the laminated battery according to the present invention, the number of the split plate springs is two.

  In the laminated battery according to the present invention, the thickness of the split plate spring is ½ of the difference between the outer diameter of the current collector and the diameter of the hole of the second electrode. In the laminated battery according to the present invention, the split plate spring is a nickel-plated steel plate. A nickel-plated steel sheet has alkali resistance and is not corroded by the electrolytic solution.

  The laminated battery according to the present invention includes a cylindrical conductive exterior body, the first electrode is electrically connected to an inner surface of the exterior body, and the second electrode is an inner surface of the exterior body. Not touching.

  The laminated battery according to the present invention further includes a separator having a hole disposed between the positive electrode and the negative electrode, and an outer edge of the separator is covered with the first electrode, A peripheral edge of a hole through which the current collector passes through the separator is covered with the second electrode, an outer edge of the second electrode is covered with the separator, and the current collector in the first electrode is The peripheral edge of the through hole is covered with the separator.

  According to this configuration, the exterior body and the first electrode are reliably separated by the separator in the vicinity of the exterior body, and the current collector and the second electrode are reliably separated by the separator in the vicinity of the current collector. There is no risk of a short circuit. In addition, since the diameter of the separator hole is smaller than the outer diameter of the current collector, the separator does not intervene between the second electrode and the current collector when the current collector is press-fitted into the electrode group. There is no waking.

  According to the present invention, there is provided a laminated battery in which contact between the hole of the second electrode and the current collector penetrating the hole is ensured and no contact failure occurs.

It is a schematic block diagram of the laminated battery using the electrode of this invention, and shows an axial cross section. It is a perspective view of a split plate spring. It is sectional drawing of the radial direction of a split plate spring. It is sectional drawing for demonstrating the dimensional relationship of a split plate spring, a collector, and a 2nd electrode. It is drawing explaining the effect | action of a split plate spring when the curvature of a split plate spring is larger than the curvature of a collector.

  Hereinafter, embodiments according to the present invention will be described with reference to the drawings. However, the present invention is not limited to the embodiments. In the description of the embodiments of the present invention, a nickel metal hydride battery will be described as an example for convenience of explanation, but the type of secondary battery is not limited to this, and a lithium ion battery, a zinc manganese battery, nickel iron A secondary battery such as a battery or nickel cadmium may be used.

  In describing each embodiment of the present invention, after describing the electrode, the laminated battery according to the present invention will be described.

  The negative electrode contains a hydrogen storage alloy such as lanthanum nickel as a main substance. Nickel oxyhydroxide was used as the positive electrode active material. As the electrolytic solution retained in the separator, an alkaline aqueous solution or a KOH aqueous solution generally used in nickel metal hydride batteries was used.

  As the negative electrode, a paste prepared by adding a solvent to a hydrogen storage alloy, a conductive filler, and a binder, applied onto a substrate, molded into a plate shape, and cured is used. Similarly, as the positive electrode, a positive electrode active material, a conductive filler, and a binder added with a solvent are applied to a substrate, formed into a plate shape, and cured.

  Carbon particles were used as the conductive filler. As the substrate, a metal plate or a metal foil having electrical conductivity such as a nickel plate can be used. In this embodiment, a nickel-plated steel plate is used.

  The separator uses a material that transmits hydrogen ions but does not transmit electrons. For example, polypropylene fibers can be used as a material for forming the separator. The separator holds an electrolytic solution. As the electrolytic solution, an alkaline aqueous solution generally used in nickel-metal hydride batteries, for example, a KOH aqueous solution, a NaOH aqueous solution, a LiOH aqueous solution, or the like can be used.

  FIG. 1 is a schematic sectional view in the axial direction of a cylindrical laminated battery (hereinafter simply referred to as a laminated battery) according to an embodiment of the present invention. A laminated battery 11 shown in FIG. 1 includes an exterior body 15, a current collector 17, and an electrode group 13 housed inside the exterior body as main components. The exterior body 15 includes a bottomed cylindrical can 12 and a disk-shaped lid member 16 attached to the opening 12c of the cylindrical can. The cylindrical can 12 and the lid member 16 are made of iron, but may be other metals. The outer diameter of the lid member 16 is slightly larger than the inner diameter of the opening 12c of the cylindrical can. The lid member 16 is closely fitted in the opening 12c of the cylindrical can after the electrode group 13 is stored.

  The electrode group 13 includes a positive electrode 13a including a positive electrode active material, a negative electrode 13b including a hydrogen storage alloy, and a separator 13c interposed between the positive electrode 13a and the negative electrode 13b that transmits ions but does not transmit electrons. Yes. The electrode group 13 is stacked in the axial direction (X direction in FIG. 1) of the cylindrical can 12 and housed in the exterior body 15. In addition, the electrolyte solution (not shown) is hold | maintained at the separator 13c. Each of the positive electrode 13a, the negative electrode 13b, and the separator 13c has a disk shape with a hole in the center. The outer diameter of the negative electrode 13b is smaller than the inner diameter of the cylindrical can 12, and the outer edge portion 13bb of the negative electrode and the inner surface 12a of the cylindrical can are not in contact. On the other hand, the outer diameter of the positive electrode 13a is larger than the inner diameter of the cylindrical can 12, the outer edge portion 13ab of the positive electrode is in contact with the inner surface 12a of the cylindrical can, and the positive electrode 13a and the cylindrical can 12 are electrically connected. Preferably, the outer diameter of the positive electrode 13 a is slightly larger than the inner diameter of the cylindrical can 12.

  The current collector 17 is made of a material obtained by applying nickel plating to iron, and includes a rod-shaped shaft portion 17a and a stopper portion 17b disposed at one end of the shaft portion 17a. By applying nickel plating, the current collector 17 is prevented from being corroded by the electrolyte contained in the separator 13c. The shaft portion 17a of the current collector passes through the center of the electrode group 13 including the positive electrode 13a, the negative electrode 13b, and the separator 13c in the axial direction of the outer package 15 (X direction in FIG. 1). The diameter of the hole provided in the center of the negative electrode 13b is larger than the outer diameter of the shaft portion 17a, and the split plate spring 19 is fitted in the gap between the negative electrode 13b and the shaft portion 17a. As a result, the peripheral edge portion 13ba of the hole of the negative electrode contacts the shaft portion 17a via the split plate spring 19, and the negative electrode 13b and the current collector 17 are electrically connected. On the other hand, the diameter of the hole provided in the center of the positive electrode 13a is larger than the outer diameter of the shaft portion 17a, the peripheral edge portion 13aa of the positive electrode hole does not contact the shaft portion 17a, and the positive electrode 13a and the current collector 17 are electrically connected to each other. Is electrically insulated.

  The electrode group 13 is disposed so as to be sequentially stacked on the stopper 17b of the current collector. The stopper 17b prevents the electrode group 13 from dropping from the end of the current collector 17 during assembly. The shape of the stop portion 17b is a disk shape. The stopper 17b is disposed on the cylindrical can bottom 12b with the insulating plate 14 interposed therebetween. The insulating plate 14 prevents the current collector 17 and the cylindrical can 12 from coming into direct contact and being electrically short-circuited. The end of the shaft portion 17a opposite to the stop portion 17b is supported by a bearing 18 provided at the center of the lid member 16. In order to prevent the cover member 16 and the shaft portion 17a from being electrically short-circuited, the bearing 18 is made of an insulating material. A shaft portion penetrating the lid member 16 constitutes a positive electrode terminal 17d. The cylindrical can 12 functions as a negative electrode terminal.

  Next, the relationship between the dimensions of the positive and negative electrodes 13a and 13b and the separator 13c and the dimensions of the outer package 15 and the current collector 17 will be described. The outer edge of the separator 13c is covered with the positive electrode 13a (first electrode), and the outer edge of the negative electrode 13b (second electrode) is covered with the separator 13c. The peripheral edge of the hole through which the current collector 17 penetrates in the positive electrode 13a is covered with the separator 13c, and the peripheral edge of the hole through which the current collector 17 penetrates in the separator 13c is covered with the negative electrode 13b.

  That is, the outer diameter of the separator 13c is larger than the outer diameter of the negative electrode 13b (second electrode). For this reason, the positive electrode 13 a and the negative electrode 13 b are completely separated by the separator 13 c in the vicinity of the inner peripheral surface of the outer package 15. For this reason, even if an electrode deform | transforms, an electrode does not contact each other. Furthermore, the diameter of the hole provided in the center of the separator 13c is smaller than the diameter of the hole provided in the center of the positive electrode 13a. For this reason, the positive electrode 13 a and the negative electrode 13 b are completely separated by the separator 13 c in the vicinity of the outer peripheral surface of the current collector 17. For this reason, even if an electrode deform | transforms, an electrode does not contact each other. Further, the outer diameter of the separator 13c is smaller than the outer diameter of the positive electrode 13a (first electrode). For this reason, the separator 13 c is not interposed between the positive electrode 13 a and the cylindrical can 12. Furthermore, the diameter of the hole provided in the center of the separator 13c is larger than the diameter of the hole provided in the center of the negative electrode 13b. For this reason, the separator 13c is interposed between the negative electrode 13b and the current collector 17, and contact failure does not occur.

  By bringing the outer edge of the positive electrode 13a into contact with the inner surface of the outer package 15 functioning as a current collecting terminal, it is possible to efficiently transmit electricity and heat generated in the positive electrode 13a to the outer package 15. Similarly, the peripheral edge of the hole through which the current collector of the negative electrode 13b passes is brought into contact with the current collector 17 functioning as a current collector terminal via a split plate spring, thereby efficiently collecting electricity generated in the negative electrode 13b. It was possible to transmit to the electric body 17.

  The split plate spring is a plate-like elastic body having conductivity, and its long side extends in the axial direction of the current collector, and its short side is curved. If it describes in the relationship on arrangement | positioning in a laminated battery, the split plate spring 19 is arrange | positioned between the axial part 17a and the negative electrode 13b of a collector. The long side of the split plate spring 19 extends along the axial direction of the current collector 17, and the short side is curved along the curved surface of the rod-shaped current collector 17. In this embodiment, a nickel-plated steel plate is used as the split plate spring, but any other conductive material may be used as long as it is an elastic conductor.

  The split plate spring will be described in detail with reference to FIGS. The description will be given for the case where the split plate spring is composed of two pieces. FIG. 2 is a perspective view of the split plate spring 4. The split plate spring 4 has a shape in which the long side extends in the vertical direction (axial direction) in FIG. 2 and the short side is curved. A current collector (not shown) is positioned at a position facing the split plate spring 4, that is, in a region surrounded by the two split plate springs 4.

  FIG. 3 is a cross-sectional view perpendicular to the axial direction of the split plate spring 4, and the illustration of another split plate spring in an axially symmetric position with respect to the center line L is omitted. The split plate spring 4 has an arc in which a part of a semicircle indicated by a radius 8.5 is missing.

  FIG. 4 is a cross-sectional view taken along the line AA of FIG. 1 and shows the positional relationship between the second electrode 2, the current collector 3, and the split plate spring 4. In FIG. 4, the figure of the state in which the split-plate spring 4 is not urged | biased is shown virtually. That is, the split plate spring 4 in FIG. 4 is overwritten in a state before being disposed between the second electrode 2 and the current collector 3. The current collector 3 has a diameter of 16.2, and the inner curved surface of the split plate spring 4 is an arc having a radius of 8.5 (diameter conversion 17.0). The curvature of the inner side of the split plate spring 4 is the current collector. Less than the curvature of. Further, the curvature of the outer side of the split plate spring is smaller than the curvature of the hole of the second electrode 2. The outer side and the inner side of the split plate spring mean the outer circumference and the inner circumference, respectively.

If the split plate spring 4 and the current collector 3 are arranged so as to contact each other at the point b, the split plate spring 4 overlaps the second electrode (indicated by w) at the end of the arc. As a result, when the split plate spring 4 is assembled between the second electrode 2 and the current collector 3, the edge of the outer curved surface of the split plate spring 4 (indicated by a point a) is biased at the periphery of the hole of the second electrode. Strong contact with the split spring force. Similarly, in the middle of the inner periphery of the split plate spring 4 (indicated by the point b), the split plate spring 4 and the current collector 3 come into contact with each other with a strong pressure due to the reaction force of the split plate spring.
As described above, the current collector 3 and the second electrode 2 can come into strong contact with each other via the split plate spring 4 to reliably collect current.

  Contact between the split plate spring and the current collector is made geometrically at a line rather than at a point. That is, the split plate spring 4 and the current collector 3 are in strong contact with each other by the reaction force of the split plate spring on the line extending in the axial direction along the long side in the middle of the split plate spring 4. However, it is not necessary for the split plate spring to contact the current collector in all regions on the line along the long side. Since the split plate spring is a good conductor of electricity, it may be in contact with the split plate spring at several points on the line. The point b shown in FIG. 4 is a representative point where the split plate spring and the current collector are in contact.

  Similarly, the peripheral edge of the hole of the split plate spring 4 and the second electrode 2 is in strong contact with the force of the biased split plate spring at a point on the ridge line extending in the axial direction on the outer curved surface side of the split plate spring 4. . However, it is not necessary for the split plate spring to be in contact with the second electrode at all four ridge lines. Any of the four ridge lines of the split plate spring may be in contact with the second electrode. A point a shown in FIG. 4 is a representative point where the split plate spring and the second electrode come into contact.

  The split plate spring 4 is obtained by cutting and bending a single metal plate into a strip shape, and its thickness is substantially uniform. The thickness of the split plate spring 4 is determined by the relationship between the dimension of the hole of the second electrode and the outer dimension of the current collector. In this embodiment, the thickness is equal to the gap between the second electrode and the current collector. If the current collector is a cylinder, the thickness of the split plate spring 4 is ½ of the difference between the hole diameter of the second electrode and the outer diameter of the current collector.

  The inner circumferential length of the split plate spring is ½ or less of the outer circumferential length of the current collector. Therefore, when the split plate springs 4 are incorporated at equal intervals between the current collector 3 and the second electrode 2, the tips of the two split plate springs 4 do not contact each other and have a gap. .

  FIG. 5 is a diagram for explaining the operation when the curvature of the split plate spring is larger than the curvature of the current collector. Since the curvature of the split plate spring is larger than that of the current collector, the split plate spring and the current collector are in strong contact at the point c due to the reaction force of the spring. Similarly, the split plate spring and the second electrode are in strong contact at point d.

  Although the case where the split plate spring is composed of two sheets has been described, a single sheet spring may be used. In this case, the length of the inner periphery of the split plate spring may be longer than ½ of the length of the outer periphery of the current collector. If the number is one, the contact force is somewhat reduced, but the split plate spring can be easily incorporated. Moreover, you may comprise by 3 sheets. In this case, the inner circumferential length of the split plate spring is 1/3 or less of the outer circumferential length of the current collector. If three sheets are used, contact can be achieved more closely, but the arrangement of three split plate springs requires a lot of assembly work.

  A method for assembling the laminated battery will be described. First, electrodes are stacked by sequentially inserting them into a round bar having the same outer diameter as that of the current collector 17 so that a separator is interposed between the positive electrode and the negative electrode, and then the current collector is fixed to both ends of the stacked electrode group 13. A pressing plate 20 including a portion 17 b and a lid member 16 is disposed to hold the electrode group 13. Then, pressure is applied to both ends of the push plate 20 to compress the electrode group 13, the round bar is pulled out while maintaining the compressed state, and the split plate spring is disposed around the hole of the second electrode, and then the current collector 17 is press-fitted into the electrode group 13, and the push plate 20 is screwed to the current collector 17 to assemble the electrode assembly while maintaining the compressed state of the electrode group. Then, after the electrode assembly is press-fitted into the exterior body, air is vented and an electrolytic solution is injected.

  The electrode for a laminated battery and the laminated battery using the same according to the present invention can be suitably used not only for industrial use but also for consumer use.

2 Second electrode 3 Current collector 4 Split plate spring 11 Cylindrical laminated battery 12 Cylindrical can (a: side inner surface)
13 electrode group (a: positive electrode, b: negative electrode, c: separator)
14 Insulating plate 15 Exterior body 16 Lid member 17 Current collector (a: shaft part, b: stopper part, c: positive electrode terminal)
18 Bearing

Claims (9)

A laminated battery comprising a positive electrode, a negative electrode, and a conductive current collector passing through the positive electrode and the negative electrode,
The positive electrode and the negative electrode are stacked along the axial direction of the stacked battery,
The first electrode that is one of the positive electrode and the negative electrode is not in contact with the current collector,
A second electrode, which is the other of the positive electrode and the negative electrode, is electrically connected to the current collector;
A conductive plate-like elastic body interposed between the current collector and the second electrode, the long side extending along the axial direction of the current collector, and the short side of the current collector A laminated battery comprising a split plate spring having an inner curvature different from the curvature.   The laminated battery according to claim 1, wherein an inner curvature of the split plate spring is smaller than a curvature of the current collector.   The multilayer battery according to claim 1, wherein an inner peripheral length on the short side is not more than ½ of an outer peripheral length of the current collector.   The laminated battery according to claim 1, wherein the number of the split plate springs is 1 to 3.   The laminated battery according to claim 4, wherein the number of the split plate springs is two.   The laminated battery according to claim 5, wherein a thickness of the split plate spring is ½ of a difference between an outer diameter of the current collector and a diameter of a hole of the second electrode.   The laminated battery according to any one of claims 1 to 6, wherein the split plate spring is a nickel-plated steel plate. It has a cylindrical conductive exterior body,
The first electrode is electrically connected to the inner surface of the exterior body;
The laminated battery according to claim 1, wherein the second electrode is not in contact with the inner surface of the exterior body. Further comprising a perforated separator disposed between the positive electrode and the negative electrode;
An outer edge of the separator is covered with the first electrode;
The peripheral edge of the hole through which the current collector passes through the separator is covered with the second electrode,
An outer edge of the second electrode is covered with the separator;
The multilayer battery according to claim 8, wherein a peripheral edge of a hole through which the current collector passes through the first electrode is covered with the separator.

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