JP2014071972A - Stacked cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problems of a conventional wound battery that it is difficult to suppress temperature rise in a battery, that it does not function as a battery when the temperature of an electrode rises, and that the battery size increases if a pipe, or the like, for feeding refrigerant is provided in the battery.SOLUTION: A battery having excellent cycle life is obtained by stacking a positive electrode and a negative electrode in the axial direction of a cylindrical exterior body, interposing a metal foil between one electrode of the positive electrode or a negative electrode and a current collector, thereby suppressing temperature rise in a battery.

Description

  The present invention relates to battery cooling, and more particularly, to a laminated battery with improved cooling performance in the battery.

  As secondary batteries, batteries of various shapes such as cylindrical batteries and square batteries have been developed and widely used. In addition, a cylindrical type is adopted for a relatively small capacity battery from the viewpoint of pressure resistance and ease of sealing, and a square type is adopted for a relatively large capacity battery for ease of handling.

  If attention is paid to the electrode structure of the secondary battery, two types, a stacked type and a wound type, are widely used. That is, in a stacked type battery, an electrode group in which positive electrodes and negative electrodes are alternately stacked via separators is housed in a battery case. Many of the stacked type batteries have a rectangular battery case, but some have a cylindrical battery case. On the other hand, a wound type battery 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. Many of the wound type batteries are cylindrical, but some are rectangular.

  Patent Document 1 and Patent Document 2 disclose techniques related to a cylindrical wound battery. Patent Document 3 discloses a cylindrical laminated battery for the purpose of increasing battery capacity by stacking disk-shaped electrodes inside a bottomed cylindrical container.

  Various methods have been proposed for the cooling structure of the secondary battery. Most of them are related to an assembled battery obtained by modularizing a plurality of secondary batteries. This is because when the secondary battery is modularized to increase the capacity, the temperature rise of the secondary battery becomes a problem. As for the cooling structure of the assembled battery, a method of providing protrusions on the surface of the container that houses the assembled battery to cause disturbance in the flow of cooling air to improve heat dissipation (for example, Patent Document 4), between adjacent assembled batteries A method of providing a cooling air passage by interposing a metal cooling plate with a hole (for example, Patent Documents 4 and 5) or a method of providing cooling fins protruding outside the storage container (for example, Patent Document 6) Has been proposed.

Patent Document 7 discloses a cooling structure for a battery unit in which a cooling plate in which a coolant channel is provided between the battery units in a prismatic stacked battery unit in which a separator is interposed between the positive electrode and the negative electrode. ing.
Patent Document 8 discloses a cylindrical wound battery in which a sheet-shaped heat sink is disposed on a positive electrode and a negative electrode and wound together with a separator.

JP 2002-198044 A JP 2004-103350 A JP 2000-48854 A JP 2009-16285 A JP 2003-7355 A JP 2001-143769 A International Publication No. 2008/099609 Japanese Patent Laid-Open No. 11-144771

  The separator, which is one of the constituent elements of the battery, has a role of preventing a short circuit between the positive electrode and the negative electrode, holding an electrolyte, and conducting ionic conduction between the positive electrode and the negative electrode, and is an important part for the battery. However, since the separator uses a nonwoven fabric of synthetic fibers such as polyamide fibers and polyolefin fibers, its thermal conductivity is small compared to the positive electrode or negative electrode (hereinafter collectively referred to as electrodes), and it is difficult to transfer heat. .

  Referring to the heat transfer of the wound battery, in order to transfer the heat generated inside the battery to the battery surface, it is necessary to transfer the heat in the radial direction of the battery. In a wound battery, separators having low thermal conductivity are stacked in multiple layers between the battery surface and the central portion, so that it is difficult to perform heat transfer well. As a result, the wound battery has a large temperature gradient in the battery and on the battery surface, and the temperature increases toward the center.

  As a result, although the surface temperature of the battery case of the wound battery is close to the ambient temperature, the temperature of the central portion is high, and particularly in the charge / discharge state, the temperature is considerably high. Even if the outside of the battery case is cooled, the inside of the battery is not cooled to a necessary level and becomes high temperature. The electrode stops functioning at higher temperatures.

  As described above, various methods for cooling the battery have been proposed (for example, Patent Documents 4, 5, and 6). However, any of these methods is effective for cooling the surface of the battery case, but it cannot be an effective cooling method for a wound battery because of the temperature gradient due to the separator.

  A method of winding a heat sink together with an electrode, or a method of storing a pipe through which cooling water flows in a battery has been proposed. These methods may be said to be more effective cooling methods than cooling the surface of the battery case, but require a space for cooling, increase the battery size, and decrease the electric capacity per volume.

  The battery described in Patent Document 3 is a battery having a battery container as one electrode terminal and a current collecting rod penetrating the electrode as the other electrode terminal, wherein the connection structure between the electrode and the terminal is simple. Yes. However, in the battery assembly process, the positive electrode and the negative electrode may be short-circuited to cause an initial failure. Furthermore, by repeating charge and discharge, the electrode may be deformed by repeated contraction and expansion, and the positive electrode and the negative electrode may be short-circuited, resulting in aged defects. Such a phenomenon shortens the cycle life of the battery.

  The present invention has been made to solve such problems, and provides a secondary battery excellent in cycle life characteristics that suppresses temperature rise inside the battery and does not cause poor contact between electrodes and terminals. To solve it.

  In order to achieve the above-described problems, a laminated battery according to the present invention is a battery in which a positive electrode and a negative electrode are laminated in the axial direction of the outer casing through a separator inside a cylindrical outer casing. The conductive current collector passes through the positive electrode, the negative electrode, and the separator in the axial direction of the outer casing, and either the positive electrode or the negative electrode is a first metal foil. A first electrode that is electrically connected to the exterior body via the other electrode, a second electrode that is not electrically connected to the exterior body, and the second electrode is a second electrode. It is electrically connected to the current collector through a metal foil, and the first electrode is not electrically connected to the current collector (Claim 1).

  According to this configuration, the separator holds the electrolytic solution, insulates between the positive and negative electrodes, and enables ion permeation. The exterior body is made of metal and functions as a terminal of the electrode (first electrode) that is electrically connected to the exterior body. On the other hand, the current collector is made of metal and functions as a terminal of the electrode (second electrode) that is electrically connected to the current collector. Further, the current collector may be iron or aluminum, and these are preferably nickel-plated.

  The positive and negative electrodes and the separator are formed in a sheet shape. The positive and negative electrodes and the separator each have a hole through which the current collector passes, and the rod-shaped current collector passes through the hole. The diameter of the hole of the first electrode is larger than the sum of the outer diameter of the rod-shaped current collector and the thickness of the second metal foil. For this reason, the first electrode is not in contact with the second metal foil and the current collector, and the first electrode and the current collector are electrically insulated. On the other hand, the diameter of the hole of the second electrode is smaller than the sum of the outer diameter of the rod-shaped current collector and the thickness of the second metal foil. For this reason, the whole or part of the periphery of the hole of the second electrode is in contact with the current collector via the second metal foil. The second electrode is electrically connected to the current collector through the second metal foil.

The exterior body is hollow, and the positive and negative electrodes and the separator are stacked in the axial direction of the exterior body, and are accommodated inside the exterior body. The outer package may preferably be a can, and may be iron, aluminum or titanium. The sum of the outer dimension of the second electrode (outer diameter in the case of a cylinder) and the thickness of the first metal foil is smaller than the inner dimension of the outer casing (inner diameter in the case of a cylinder). The second electrode and the exterior body are electrically insulated without contact with the foil and the exterior body. On the other hand, the sum of the outer dimension of the first electrode and the thickness of the first metal foil is larger than the inner dimension of the exterior body. The first electrode is in contact with the inner surface of the exterior body through the first metal foil, either entirely or partially at the outer edge thereof. That is, the first electrode is electrically connected to the exterior body via the first metal foil. Since the first electrode is press-fitted into the exterior body, the heat generated in the first electrode is transmitted to the exterior body with a small resistance and effectively acts on the cooling of the electrode.
The first and second metal foils are attached so as to be in contact with the side surface and the hole of the electrode, respectively, in a state where the electrode is assembled.

  The heat generated in the first electrode is directly transferred to the exterior body. The temperature gradient (temperature difference) is small because there is no defective heat conductor in the middle. Heat generated in the second electrode is transmitted to the first electrode through the separator. A separator with a low thermal conductivity is interposed in the middle, but only one sheet does not provide a large thermal resistance, so the temperature gradient can be kept small. Furthermore, the second electrode is strongly pressed against the first electrode by pushing the electrode group consisting of the positive and negative electrodes and the separator into the exterior body with a large pressure in the axial direction, so that the heat transfer of the second electrode becomes larger. . The temperature gradient of the wound battery is large because the separator between the outer body and the electrode, which is difficult to transfer heat, cannot be wound with a large force due to its structure. This is because the movement cannot be increased.

The overall heat transfer coefficient (U ₁ ) of the wound battery is expressed by Equation 1 as will be described later. On the other hand, the overall heat transfer coefficient (U ₂ ) of the laminated battery according to the present invention is expressed by Equation 2. Comparing the two, it can be said that a large difference occurs in the term of the number of times n. Specific numerical values will be described in detail in the description of the embodiment, but the overall heat transfer coefficient decreases as the number n of wound batteries increases.

  As described above, the temperature gradient of the laminated battery according to the present invention is small, and the temperature rise at the center of the laminated battery can be reduced. For this reason, since it is not necessary to provide a pipe or the like for flowing a refrigerant inside the battery, the temperature rise can be suppressed with a compact structure. Furthermore, since the exterior body can be cooled relatively easily, it is possible to easily suppress the temperature rise of the battery.

The laminated battery according to the present invention preferably has a plurality of protrusions on at least one surface of the first metal foil or the second metal foil.
According to this configuration, these metal foils are three-dimensionally processed so as to have a large number of protrusions formed so as to protrude on the surface thereof. As the secondary battery is charged / discharged, the volume of the electrode changes, but the protrusions provided on the metal foil deteriorate the contact between the first electrode and the exterior body and between the second electrode and the current collector. Makes it possible to prevent. The cycle life characteristics of the battery can be improved.

In the laminated battery according to the present invention, it is preferable that the protrusion provided on the first metal foil or the second metal foil has a frustum shape in which the area of the bottom is larger than the area of the top.
According to this configuration, protrusions can be formed by providing irregularities on the surface of the metal foil. In this case, protrusions are formed on both surfaces of the metal foil. If attention is paid to the convex and concave portions of the metal foil, the shape thereof becomes a frustum shape. Specifically, it is a polygonal frustum or a truncated cone. The area of the protrusion (top) of the protrusion is smaller than the area of the bottom of the protrusion, and the longitudinal section thereof is trapezoidal. The electrode bites into the frustum-shaped protrusion, and effectively works to keep good contact between the first electrode and the outer package and between the second electrode and the current collector. Since the area of the bottom is larger than the area of the top, the electrode stably bites into the protrusion of the metal foil.

In the laminated battery according to the present invention, it is preferable that a tip portion of the protrusion provided on the first metal foil or the second metal foil is bent in a direction opposite to the protrusion.
According to this configuration, the metal foil has a “cache” in which the tip of the protrusion is bent in the direction opposite to the protrusion. This bite causes the electrode to bite and catch, thereby ensuring contact between the first electrode and the exterior body and between the second electrode and the current collector regardless of the expansion and contraction of the electrode accompanying charging and discharging.

In the laminated battery according to the present invention, a hole is provided at a tip portion of the protrusion provided in the first metal foil or the second metal foil, and the outer battery protrudes outward from a peripheral edge of the hole. Preferred (claim 5).
According to this configuration, it is possible to easily provide a cache at the tip or top of the protrusion.

  In the laminated battery according to the present invention, the outer edge of the separator is covered with the first electrode, the outer edge of the second electrode is covered with the separator, and the current collector of the first electrode penetrates. The peripheral edge of the hole is covered with the separator, and the peripheral edge of the hole penetrating the current collector of the separator is covered with the second electrode.

According to this configuration, since the outer edge of the second electrode is covered with the separator in a state where the electrode and the separator are stacked, the first electrode and the second electrode are reliably separated by the separator at the outer edge portion. Has been. The first electrode and the second electrode do not contact (short-circuit) at the outer edge portion due to the deformation of the electrode. Similarly, since the periphery of the hole through which the current collector of the first electrode passes is covered with the separator, the first electrode and the second electrode are reliably separated by the separator at the periphery of the hole. The first electrode and the second electrode do not contact (short-circuit) at the peripheral portion of the hole due to the deformation of the electrode.
In the state where the first electrode and the second electrode are stacked, the separator does not become an obstacle when the first metal foil is attached to the outer edge portion of the first electrode. Moreover, since the peripheral part of the hole of the separator through which the current collector passes is covered with the second electrode, the separator does not become an obstacle to attaching the second metal foil to the peripheral part of the hole of the second electrode.
When the electrode is disk-shaped, the outer diameter of the first electrode is larger than the outer diameter of the separator, and the outer diameter of the separator is larger than the outer diameter of the second electrode. When the current collector is a round bar, the hole diameter of the first electrode is larger than the hole diameter of the separator, and the hole diameter of the separator is larger than the hole diameter of the second electrode. According to this configuration, the positive electrode and the negative electrode are not accidentally short-circuited during assembly. There is no short circuit between the electrodes due to the deformation of the electrodes.

In the laminated battery according to the present invention, it is preferable that the current collector has a pipe-shaped side portion (Claim 7).
In this configuration, part or all of the side part of the current collector is covered with the pipe, so when the connection between the current collector and the electrode is loose, the pipe part of the current collector is connected to the inner diameter of the pipe. By driving a slightly larger pile, the outer diameter of the current collector can be increased. Thereby, the coupling | bonding of a collector and an electrode can be strengthened.

In the laminated battery according to the present invention, it is preferable that a slit is provided in the axial direction of the pipe-shaped side portion of the current collector.
According to this configuration, when a pile slightly larger than the inner diameter of the pipe is driven into the pipe portion of the current collector, the slit is widened. Thereby, the outer diameter of the current collector can be widened with a small resistance, and the coupling between the current collector and the electrode can be tightened. If there is no slit in the pipe portion of the current collector, the outer diameter of the current collector is difficult to expand when a pile is driven into the current collector if the current collector is thick. When the wall thickness is thin, the electrical conductivity of the current collector becomes poor.

In the laminated battery according to the present invention, it is preferable that a side surface of the current collector has an uneven shape.
According to this configuration, the current collector has an uneven shape on the side surface. The diameter of the hole through which the current collector provided in the second electrode passes is smaller than the sum of the concave diameter of the current collector and the thickness of the second metal foil. Thereby, even if the volume of the electrode changes with charge / discharge, it becomes possible to ensure sufficient contact between the second electrode and the current collector by the anchor effect due to the uneven shape. Examples of the method for providing the uneven shape include existing methods such as etching, knurling, knurling, embossing, screwing, and laser processing.

In the laminated battery according to the present invention, a groove is formed on a side surface of the current collector, and a sum of a groove trough diameter of the current collector and a thickness of the second metal foil is applied to the second electrode. The diameter of the groove of the current collector and the sum of the thickness of the second metal foil are larger than the diameter of the hole through which the current collector is provided, and the current collector provided in the first electrode penetrates. It is preferable that it is smaller than the diameter of the hole to be formed.
According to this configuration, the groove provided on the side surface of the current collector is preferably a screw groove. The groove valley is the thinnest part of the current collector. The second electrode is in close contact with the screw groove via the second metal foil. Groove mountain is the thickest part of the current collector. The first electrode is not in contact with the current collector.

  If the current collector is not subjected to thread groove processing, the connection between the current collector and the electrode may be loosened during assembly of the electrode, and intimate contact between the current collector and the electrode may be hindered. In order to solve such a problem, the current collector was subjected to thread groove processing. In other words, the second electrode can be strongly fitted along the lead of the screw formed on the current collector. As a result, it is possible to prevent the electrode from coming off the current collector during assembly processing.

  In the laminated battery according to the present invention, it is preferable that a charge capacity of the negative electrode is smaller than a charge capacity of the positive electrode. Generally, in an alkaline secondary battery, positive electrode regulation is adopted for sealing, and a larger negative electrode capacity is required than a positive electrode capacity. However, the laminated battery is a so-called negative electrode regulation. Here, each charge capacity may be simply referred to as a positive electrode capacity or a negative electrode capacity.

Therefore, in the laminated battery according to the present invention, in a state where charging has progressed, the negative electrode is fully charged before the positive electrode is fully charged. In a nickel metal hydride battery regulated by a negative electrode, hydrogen gas is generated in the negative electrode according to the following reaction formula (1) at the time of overcharge in which charging is further performed from a fully charged state.
H ⁺ + e ⁻ → 1 / 2H ₂ (1)

The generated hydrogen gas is accumulated inside the exterior body, but may be stored in a separately provided hydrogen gas storage chamber. During the discharge, the hydrogen gas accumulated or stored in the exterior body is occluded in the hydrogen storage alloy of the negative electrode and becomes an energy source for the discharge. The reaction formula at the time of discharge is shown in (2).
Negative electrode 1 / 2H ₂ → H ⁺ + e ⁻
Positive electrode NiOOH + e ⁻ + H ⁺ → Ni (OH) ₂ (2)
Overall NiOOH + 1 / 2H ₂ → Ni (OH) ₂

  The negative electrode of the nickel metal hydride battery includes a hydrogen storage alloy that is a rare metal. Hydrogen storage alloys are expensive. The cost of the negative electrode is said to occupy 80% of the entire electrode, and the negative electrode cost has a great influence on the battery price. In the secondary battery regulated by the positive electrode, the amount of the negative electrode material is 1.5 to 2 times that of the positive electrode material. However, according to the configuration of the present invention, the amount of expensive negative electrode material can be reduced. For this reason, an inexpensive battery can be obtained. Even if the negative electrode capacity decreases, the hydrogen gas stored by overcharging is used at the time of discharging, so that the battery capacity does not decrease.

  The laminated battery according to the present invention preferably includes a hydrogen storage chamber for storing hydrogen gas generated at the negative electrode inside the outer package. In this configuration, the hydrogen storage chamber may be an independent space. Further, the hydrogen storage chamber is not an independent space but may be a gap between electrodes or separators. In fact, hydrogen can be stored between the positive electrode active material or the hydrogen storage alloy.

  In the laminated battery according to the present invention, it is preferable that the hydrogen storage alloy contained in the negative electrode is charged using hydrogen gas stored in the hydrogen storage chamber (claim 13). According to this configuration, the hydrogen gas generated by overcharging is used effectively by charging the negative electrode. The hydrogen storage alloy contained in the negative electrode functions as a catalyst.

In the method for assembling the laminated battery according to the present invention, a round bar slightly smaller than the inner diameter of the negative electrode is projected at the center of a cylinder having an inner diameter slightly larger than the outer diameter of the positive electrode, and the positive electrode and the negative electrode are placed on the round bar. After sequentially inserting the electrodes so that the separator is interposed between them and stacking the electrodes, the electrode group stacked from the cylinder and the round bar are taken out integrally, and the first metal foil is attached to the outer periphery of the positive electrode, and the axial direction The positive electrodes adjacent to each other are electrically connected, the round bar is extracted from the electrode group, the second metal foil is attached to the inner periphery of the negative electrode, and the first and second metal foils are attached. An electrode group is press-fitted into the exterior body, and the current collector larger than the inner diameter of the negative electrode is press-fitted into the electrode group, air is evacuated, and an electrolytic solution is injected (claim 14).
According to this assembling method, the electrode assembly is press-fitted into an exterior body composed of a cylindrical can with a bottom, and after the electrolyte is injected, the cylindrical can is sealed with the lid member to seal the battery.

  The present invention makes it possible to provide a battery that suppresses temperature rise inside the battery and does not require extra space for cooling. Furthermore, a secondary battery that does not cause poor connection between electrodes and terminals is provided.

It is a schematic block diagram of the cylindrical laminated battery which concerns on 1st embodiment of this invention, and is a figure which shows an axial direction cross section. It is a figure for demonstrating the assembly method of a cylindrical laminated battery. It is a figure for demonstrating the various shapes of metal foil. It is the figure which showed typically the screw structure of the electrical power collector, and is the elements on larger scale when an electrode group is inserted in the electrical power collector. It is drawing (a top view and a side view) of the collector of a longitudinal groove structure. They are sectional drawing (a) of metal foil 3, and a top view (b). They are sectional drawing (a) of metal foil 4, and a top view (b). 3 is an image diagram for explaining the structure of a current collector 2. FIG. It is an image figure for demonstrating the structure of the electrical power collectors 3-5. It is a graph which shows the temperature rise test result of a battery.

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 for convenience of explanation, but the type of the secondary battery is not limited to this, and a lithium ion battery, a zinc manganese battery, a nickel iron battery, nickel A secondary battery such as cadmium may be used.
Prior to describing each embodiment of the present invention, how to make an electrode common to all the embodiments will be described.
<About electrode production>

  The negative electrode contains, as a main active material, a hydrogen storage alloy such as lanthanum nickel generally used in nickel-hydrogen secondary batteries (hereinafter simply referred to as nickel-hydrogen batteries). Any positive electrode active material may be used as long as it is generally used in nickel-metal hydride batteries.

  As the negative electrode, a hydrogen storage alloy, a conductive filler, and a resin that are made into a paste by adding a solvent, applied onto a substrate, formed into a plate, and cured can be used. Similarly, as the positive electrode, a positive electrode active material, a conductive filler, and a resin added with a solvent to form a paste, which is applied on a substrate, formed into a plate, and cured can be used.

  Conductive fillers include carbon fiber, carbon fiber nickel-plated, carbon particles, carbon particles nickel-plated, organic fibers nickel-plated, fibrous nickel, nickel particles, nickel Any of the foils can be used alone or in combination. Examples of the resin include thermoplastic resins having a softening temperature of 120 ° C., resins having a curing temperature from room temperature to 120 ° C., resins that dissolve in a solvent at a temperature of 120 ° C. or less, resins that dissolve in a solvent soluble in water, and alcohol. Resins that are soluble in a soluble solvent can be used. As the substrate, a metal plate having electrical conductivity such as a nickel plate can be used.

  The separator uses a material that transmits hydrogen ions but does not transmit electrons. As a material for forming the separator, for example, polyolefin fibers such as polyethylene fibers and polypropylene fibers, polyphenylene sulfide fibers, polyfluoroethylene fibers, polyamide fibers, and the like can be used. 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.

  The electrode and separator formed in the form of a sheet are wound into a band having a predetermined width and stored and transported. This strip-shaped electrode or separator is cut in accordance with the shape of the exterior body to form an electrode and a separator. Since electrodes, especially the negative electrode, are expensive, considering the yield, it is also possible to manufacture a disk-like electrode by arranging a trapezoidal or triangular electrode piece with the side of the belt-like sheet as the base and combining them in a circular shape. Is possible.

<First embodiment of laminated battery>
FIG. 1 shows a schematic sectional view in the axial direction of a cylindrical laminated battery according to the first embodiment of the present invention. A cylindrical laminated battery 11 (hereinafter simply referred to as a laminated battery) shown in FIG. 1 includes an exterior body 15, a current collector 17, and an electrode body 13 housed inside the exterior body as main components. The laminated battery 11 is manufactured using a cylindrical can having a nominal diameter of 500 mm. The exterior body 15 includes a bottomed cylindrical can 12 and a disk-shaped lid member 16 attached to the opening 12 c of the cylindrical can 12. The cylindrical can 12 and the lid member 16 are made of iron plated with nickel, 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, and the lid member 16 is tightly fitted in the cylindrical can opening 12c after the electrode body 13 is stored in the cylindrical can 12. In the first embodiment, a cylindrical can is used, but a square can may be used. If a square can is used, a square battery is obtained.

  The electrode body 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. . The electrode body 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 current collector 17 is made of a conductive material in which nickel is plated on iron, and includes a rod-shaped shaft portion 17a and a stopper portion 17b disposed at one end of the shaft portion 17a. The other end of the shaft portion 17 a 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. By applying nickel plating to the current collector 17, 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 body 13 composed of the positive electrode 13a, the negative electrode 13b, and the separator 13c in the axial direction of the exterior body 15 (X direction in FIG. 1).

  The electrode body 13 is arranged so as to be sequentially stacked on the current collector stop portion 17 b, and the stop portion 17 b prevents the electrode body 13 from falling off the end of the current collector 17. The shape of the stop portion 17b is a disk shape. The stopper 17b is disposed on the cylindrical can bottom 12b via the insulating plate 14. The insulating plate 14 prevents the current collector 17 and the cylindrical can 12 from coming into direct contact and being electrically short-circuited. A shaft portion penetrating the lid member 16 constitutes a positive electrode terminal 17c. The cylindrical can 12 functions as a negative electrode terminal.

Next, the dimensions of each part of the electrodes 13a and 13b and the dimensional relationship between the outer package 15 and the current collector 17 will be described.
The outer diameter of the separator 13c is smaller than the outer diameter of the positive electrode 13a (first electrode) and 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. Moreover, the negative electrode 13b is isolated from the exterior body 15 also by the separator 13c. Furthermore, the diameter of the hole provided in the center of the separator 13c is smaller than the diameter of the hole of the positive electrode 13a and larger than the diameter of the hole of the negative electrode 13b. For this reason, the positive electrode 13a and the negative electrode 13b are completely separated by the separator 13c in the vicinity of the outer peripheral surface of the current collector 17, and the electrodes do not contact each other even if the electrodes are deformed. The positive electrode 13a is separated from the current collector 17 by a separator 13c.

  The metal foil 10a (first metal foil) is interposed between the positive electrode 13a and the inner peripheral surface 12a of the cylindrical can, and electrically connects the positive electrode 13a and the outer package 15. The metal foil 10b (second metal foil) is interposed between the negative electrode 13b and the current collector shaft 17a, and electrically connects the negative electrode 13b and the current collector 17. As shown in FIG. 2, the metal foil 10 a has a belt shape, and is disposed between the electrode body 13 and the exterior body 15 at an interval of 90 degrees in the axial direction of the exterior body 15. Moreover, the metal foil 10b is arrange | positioned so that the axial part 17a of an electrical power collector may be enclosed. The metal foil 10a may be disposed on the entire inner surface of the exterior body 15.

  The inner diameter of the cylindrical can 12 is larger than the sum of the outer diameter of the negative electrode 13b and the thickness of the metal foil 10a, and the outer edge portion 13bb of the negative electrode does not contact the metal foil 10a, so that the negative electrode 13b and the outer package 15 are electrically insulated. It is in a state. On the other hand, the inner diameter of the cylindrical can 12 is smaller than the sum of the outer diameter of the positive electrode 13a and the thickness of the metal foil 10a, and the outer edge portion 13ab of the positive electrode contacts the inner surface 12a of the cylindrical can via the metal foil 10a. The cylindrical can 12 is electrically connected.

  The sum of the outer diameter of the shaft portion 17a and the thickness of the metal foil 10b is larger than the diameter of the hole provided in the center of the negative electrode 13b, and the peripheral edge portion 13ba of the negative electrode hole is in contact with the shaft portion 17a via the metal foil 10b. The negative electrode 13b and the current collector 17 are electrically connected. On the other hand, the sum of the outer diameter of the shaft portion 17a and the thickness of the metal foil 10b is smaller than the diameter of the hole provided in the center of the positive electrode 13a, and the peripheral portion 13aa of the positive electrode hole does not contact the metal foil 10b. The positive electrode 13a and the current collector 17 are electrically insulated.

Although the thickness of metal foil 10a, 10b is not specifically limited, It is preferable that it is smaller than the thickness of the positive electrode 13a or the negative electrode 13b. Although depending on the thickness of the positive electrode 13a or the negative electrode 13b, the thickness of the metal foils 10a and 10b is preferably 10 to 100 μm. More preferably, it is 20-50 micrometers. When the thickness of the metal foils 10a and 10b is large, the size of the battery increases. Further, when the thickness of the metal foils 10a and 10b is small, the metal foil does not exhibit its function.
The metal foils 10a and 10b have a large number of protrusions formed so as to protrude on the surface thereof. The shape of the protrusion is not particularly limited, but for example, a shape as shown in FIG. 3 is conceivable. 3, (a) has protrusions 41 on one side of the metal foil K, and (b) has protrusions 51 on both sides of the metal foil K. (C) is a metal foil K in which a hole 62 is formed with a needle or the like to form a protrusion 61, which is relatively easy to process. Further, (d) is one in which a protrusion is provided on the protrusion. That is, the hole 71 is formed in the metal foil K with a needle or the like to form the protrusion 71. Through the penetration of the needle or the like, the tip of the protrusion 71 opens outward, and the opening 73 expands toward the tip of the protrusion 71. By making the metal foil into the shape as shown in (d), the metal foils 10a and 10b bite into the electrodes 13a and 13b, and the bondability with the electrodes 13a and 13b is improved.

  Thus, a protrusion is provided and the metal foil interposed between an electrode and an exterior body or a current collector has a three-dimensional structure. When the protrusions bite into the electrodes, it is possible to ensure the bonding between the positive electrode and the outer package or between the negative electrode and the current collector. In addition, even if the volume of the electrode changes due to the charging / discharging of the battery, since the protrusion is engaged with the electrode, it is possible to suppress contact failure between the electrode and the terminal. This improves the cycle life characteristics.

A method for assembling the laminated battery of the present invention will be described with reference to FIG.
(1) The positive electrode 13a, the negative electrode 13b, and the separator 13c are punched out to predetermined dimensions. Then, a round bar 90 having a slightly smaller diameter than the hole diameter of the negative electrode is protruded at the center of the cylinder 91 having a slightly larger inner diameter than the outer diameter of the positive electrode.
(2) The negative electrode 13b, the separator 13c, the positive electrode 13a, and the separator 13c are sequentially passed through the round bar 90 to assemble an electrode group.
(3) Next, the electrode group is taken out from the cylinder 91 together with the round bar 90, the first metal foil 10a is attached to the side surface of the electrode group, and the positive electrodes adjacent in the axial direction are electrically connected to each other.
(4) The round bar 90 is extracted from the electrode group, and the second metal foil is attached to the inner peripheral surface of the hole of the negative electrode 13b.
(5) The electrode group to which the metal foils 10a and 10b are attached is press-fitted into the cylindrical can 12.
(6) Next, the current collector 17 is press-fitted into the hole of the electrode group, and a lid member (not shown) is fitted into the opening of the cylindrical can 12. And the laminated battery of this invention is manufactured by ventilating the inside of an exterior body, adding electrolyte solution, and sealing.

<Second embodiment>
A second embodiment in which a part of the first embodiment is changed will be described focusing on the changed portion. In the second embodiment, as shown in FIG. 4A, the side surface of the current collector 27 is threaded to form a screw portion 27c. That is, the side surface of the current collector 27 has a screw structure in which the trough diameter is d and the crest diameter is D (d <D). The specification of the screw is the M screw referred to in JIS, but may be the ISO specification.

  FIG. 4B is a cross-sectional view schematically showing the relationship between the current collector 27 and the electrode body 23. As shown in this figure, a second metal foil 25 b is interposed between the negative electrode 23 b and the current collector 27. Thereby, the negative electrode 23b is screwed together with the shaft portion 27a together with the metal foil 25b, and the negative electrode 23b and the current collector 27 are electrically connected. On the other hand, the positive electrode 23 a is not in contact with the current collector 27 and is insulated from the current collector 27.

  If the current collector is not subjected to thread groove processing, the connection between the current collector and the electrode may be loosened during assembly of the electrode, and intimate contact between the current collector and the electrode may be hindered. In order to solve such a problem, the current collector was subjected to thread groove processing. In other words, the second electrode can be strongly fitted along the lead of the screw formed on the current collector. As a result, it is possible to prevent the electrode from coming off the current collector during assembly processing.

  FIG. 5 shows a plan view and a side view of a current collector 17 ′ according to a modification of the second embodiment. The current collector 17 ′ is provided with a V-shaped groove in the direction of the side surface axis, and its cross section has a sawtooth shape. The serrated tip may be somewhat rounded. Since the current collector has a sawtooth cross section, the contact surface with the electrode is large, and when the electrode is consolidated in the axial direction, the electrode slides along the groove and is not easily damaged. Even if the electrode is deformed during the charge / discharge process, the electrode slides along the groove, so that the electrode is not damaged.

Next, the operation and effect of this embodiment will be described.
<About cooling structure>
The positive electrode 13a is strongly pressed against the inner surface 12a of the cylindrical can through the metal foil 10a, and the positive electrode 13a and the outer package 15 are in close contact with each other. The heat generated at the positive electrode 13 a is directly transmitted to the exterior body 15. The heat generated in the negative electrode 13b is transferred to the positive electrode 13a through the separator 13c. Although the separator 13c is difficult to transmit heat, it is thin and only one sheet does not hinder heat conduction. As described above, the heat generated in the positive electrode 13a and the negative electrode 13b is transmitted to the outer package 15 with a small temperature gradient, and it is possible to suppress the temperature rise inside the multilayer battery.

  According to such a structure, it is not necessary to provide a pipe or the like for flowing a refrigerant inside the battery, and the temperature rise of the battery can be suppressed with a compact structure. Furthermore, since the exterior body 12 is exposed to the outside, it can be cooled relatively easily, and the temperature rise can be effectively suppressed as compared with the conventional wound battery. Here, the difference in temperature rise between the laminated battery according to the embodiment of the present invention and the conventional wound battery is shown as a calculation example.

The overall heat transfer coefficient (U1) of the wound battery is expressed by Equation 1, and the overall heat transfer coefficient (U2) of the laminated battery according to the present invention is expressed by Equation 2.

Here, calculation will be made taking an 18650 type battery as an example. The specifications of the wound battery
_{t = 0.5mm, t + = t} - = t s = 10μm, k = k + = k - = 40Wm -2 deg -1
h ₀ = 100 Wm ^-2 deg ^-1 , h ₁ = 1 Wm ^-2 deg ^-1 , k _s = 1 Wm ^-2 deg ^-1 , n = 9 / 0.03 = 300
By substituting these values into Equation ₁ , U ₁ = 0.0011 Wm ⁻² deg ⁻¹ is obtained.

On the other hand, the specifications when applied to the laminated battery according to this embodiment are:
h ₀ = 100 Wm ^-2 deg ^-1 , t = 0.5mm, k = 40Wm ^-2 deg ^-1
h ₁ = 10000 Wm ^-2 deg ^-1 , t ^* = 0.009m, k ^* = 40Wm ^-2 deg ^-1
Therefore, by substituting these values into Equation ₂ , U ₂ = 100 Wm ⁻² deg ⁻¹ is obtained.
Comparing the two, it can be said that the cooling structure according to the present invention is excellent in heat transfer nearly 100,000 times as compared with the conventional wound battery.
<About the amount of active material>
In the laminated battery according to the embodiment of the present invention, there are two types of the amount of the active material. One is the conventional positive electrode regulation, and the other is the negative electrode regulation in which the negative electrode capacity is smaller than the positive electrode capacity. In the embodiment of the present invention, in the case of the positive electrode regulation type, the negative electrode capacity is 1.7 times the positive electrode capacity. On the other hand, in the case of the negative electrode regulation type, the negative electrode capacity is 80% of the positive electrode capacity. The positive electrode capacity is 1000 mAh in all cases.

  A battery of a positive electrode regulation type generates oxygen gas from the positive electrode when charged at 1000 mAh or more, but does not generate hydrogen gas from the negative electrode. Oxygen gas generated from the positive electrode reacts with hydrogen occluded in the negative electrode to become water, so that an increase in pressure inside the battery is suppressed and the battery can be sealed.

  On the other hand, when the battery of the negative electrode regulation type is overcharged, hydrogen gas is generated from the negative electrode. That is, when charged at 800 mAh or more, hydrogen gas is generated from the negative electrode (see reaction formula (1)). The generated hydrogen gas is occluded in the negative electrode and becomes fully charged, but the hydrogen gas that is not occluded in the negative electrode is stored inside the battery and the pressure inside the battery rises. If there is a hydrogen gas storage chamber, a large amount of hydrogen gas can be accumulated in the battery. Since the outer package 15 of the laminated battery has a sealed structure, the accumulated hydrogen gas does not leak to the outside.

  When the stacked battery is discharged, hydrogen stored in the negative electrode releases hydrogen ions and electrons. However, the hydrogen gas stored in the stacked battery is stored in the hydrogen storage alloy, and the fully charged state of the negative electrode continues. Reaction formula (2)). Since hydrogen gas becomes an energy source during discharge, it is not wasted. Since the hydrogen storage alloy has a catalytic action, the volume change of the negative electrode during charging and discharging is small. Thereby, the deterioration of the negative electrode is prevented and the life can be extended.

  The negative electrode is said to account for 80% of the electrode price and is expensive. According to the present invention, the positive electrode-regulated battery requires a negative electrode 1.7 times as large as the positive electrode, but by setting the amount of the negative electrode to 80% of the positive electrode, the price of the electrode can be halved. It becomes. Even if the amount of the negative electrode is reduced, the battery capacity is not reduced by using the hydrogen gas stored by overcharging.

<Examination of main specifications>
In the present invention, the specifications of the metal foil and the current collector as the main parameters were examined. And since the performance evaluation test as a battery was done, this is demonstrated below.
<Examination of metal foil>
Table 1 shows the specifications of the metal foil used in the performance evaluation test.
The metal foil 1 is a nickel foil having a thickness of 25 μm.
The metal foil 2 is obtained by making staggered cuts on the metal foil 1 and stretching it into a rhombus-shaped mesh, and the total thickness of the metal foil after processing is 50 μm.
The metal foil 3 is obtained by knurling the metal foil 1 and providing a large number of protrusions. FIG. 6A shows a cross-sectional view of the metal foil 3, and FIG. 6B shows a plan view of the metal foil 3. As shown in FIGS. 6A and 6B, the metal foil 3 has a large number of protrusions 21 formed so as to protrude. Here, a nickel foil having a thickness (h1) of 25 μm was used. This nickel foil is formed with a quadrangular pyramid-shaped protrusion 21 composed of a structural upper portion L1 and a structural lower portion L2. The protrusion 21 is formed in a quadrangular frustum shape in which the area of the upper structure L1 (projection) is smaller than the area of the lower structure L2. The vertical and horizontal lengths (X and Y directions in FIG. 6) of the lower structure L2 are all 1 mm, and the vertical and horizontal lengths of the upper structure L1 are both 0.3 mm. The thickness (h2) of the metal foil 3 including the protrusions 21 is 300 μm.

The metal foil 4 is obtained by embossing the metal foil 1 to provide a large number of protrusions and through-holes, and also providing burrs. FIG. 7A shows a cross-sectional view of the metal foil 4 and FIG. 7B shows a plan view of the metal foil 4. As shown in FIGS. 7A and 7B, the metal foil 4 has a large number of protrusions 31 formed so as to protrude. A through hole is provided at the top of the projection 31 to form an opening 32. The opening 32 is provided with an edge 33 extending in the direction opposite to the protrusion 31. The metal foil 4 was a nickel foil having a thickness (h1) of 25 μm. On this nickel foil, a quadrangular pyramid-shaped projection 31 composed of an upper structure L1 and a lower structure L2 is formed. The vertical and horizontal lengths (X and Y directions in FIG. 7) of the lower structure L2 are both 1 mm, and the vertical and horizontal lengths of the upper structure L1 are both 0.5 mm. The thickness (h2) of the metal foil 4 including the protrusions 31 is 0.5 mm. The size (h3) of the barley 33 is 0.15 mm.
The metal foil 5 is a steel material having the same structure as the metal foil 4 and having a material plated with nickel.

<Examination of current collector>
Table 2 shows the specifications of the current collector used in the performance evaluation test.
The materials of the current collectors 1 to 5 are all steel materials subjected to nickel plating except for the pipe portion.
The current collector 1 is a round bar having a diameter of 15.2 mm.
The current collector 2 was obtained by driving a 14.1 mm diameter SUS pile into a pipe having an outer diameter of 15.2 mm and an inner diameter of 14 mm (see FIG. 8A) to form a current collector with an outer diameter of 15.2 mm. (See FIG. 8B).
The current collectors 3 to 5 are formed by driving a metal pile having a diameter of 14.1 mm into a pipe having an inner diameter of 10 mm (see FIG. 9A) provided with slits on the side portions, and a current collector having an outer diameter of 15.2 mm. (See FIG. 9B).
Here, the current collector 3 uses copper as a metal pile.
The current collector 4 is obtained by knurling the side surface using a copper pile. In the knurling, the angle between the peaks and valleys was 90 °, and the corners of the peaks and valleys were processed so as to be connected to each other from an arc having a radius of 0.06 mm.
The current collector 5 has a side surface threaded using a copper pile. The screw machining was M16 (ISO standard dimension), the screw pitch was 2 mm, the outer diameter was 16.0 mm, and the inner diameter was 14.9 mm.

<Performance evaluation test as a battery>
Before conducting the temperature rise test of the laminated battery of the present invention, the performance as a battery was examined. Table 3 shows combinations of the metal foil and current collector employed in the test. The battery is a laminated battery according to the second embodiment, and a cylindrical can having a nominal diameter of 500 mm was used as the outer package.

The battery performance evaluation test was performed by discharging 0.2C after charging the SOC to 100% at a predetermined current density (0.5C, 1C, 2C, 5C, 8C). That is, the amount of discharged electricity was measured, and the charging efficiency at each charging rate was calculated. In addition, the electric capacity obtained by 0.2 C discharge after 0.5 C charge was made into battery capacity 100%. As measurement conditions, the discharge cut-off voltage was 0.8 V, the ambient temperature was 15 ° C., and the blowing condition was 1 m / s.
Table 4 summarizes the charging efficiency at each charging rate for the batteries of Examples 1 to 10 and Reference Examples 1 and 2.

  From Table 4, it can be seen that the charging efficiency characteristics are improved by interposing the first metal foil between the first electrode and the inner surface of the exterior body. In addition, it can be seen that the charging efficiency characteristics are further improved by interposing the second metal foil between the second electrode and the current collector.

  Among the metal foils 1 to 5, the metal foil 4 and the metal foil 5 which were embossed roll processed, provided with a large number of protrusions (irregular shapes) and through holes, and provided with burrs were the best.

  It can be seen that among the current collectors 1 to 5, the current collector side surface provided with an uneven shape has improved charging efficiency characteristics. In particular, the one with the threaded side surface (current collector 5) had the best performance.

<Temperature rise test results>
Since the cooling capacity of the laminated battery according to the present invention was confirmed by a test, the result will be described below. The test was performed using the battery of Example 5 (see Table 4) that had the best charging efficiency characteristics. That is, charging was performed at 0.5 C to 8 C, and the internal temperature and surface temperature of the laminated battery were examined after full charging. The temperature was measured by attaching a thermocouple to the current collector for the battery internal temperature, and attaching the thermocouple to the surface of the exterior body of the laminated battery for the surface temperature. In addition, room temperature was 15 degreeC and it measured in the ventilation state of 1 m / s.

  Table 5 shows the battery temperature measurement results after charging so that the SOC becomes 100% at each charge rate (0.5C, 1C, 2C, 5C, 8C). That is, the left column of Table 5 shows the largest difference between the battery surface temperature and room temperature (= side temperature−room temperature), and the right column shows the difference between the battery internal temperature and room temperature (= core temperature−room temperature). ) Is the largest value. At any charge rate, the temperature difference between the battery temperature and room temperature rose rapidly from the vicinity where the SOC exceeded 80%. At a charge rate of 2C or less, the battery temperature difference (side temperature-room temperature, core temperature-room temperature) was less than 5 ° C. Moreover, in 8C charge, these temperature differences were less than 30 degreeC.

  Table 6 shows a summary of values where the temperature difference between the temperature (side temperature) of the battery outer body and the temperature (core temperature) of the central portion was the largest after charging at a predetermined current density. Even when charging is performed at 3C or less, the temperature difference between the side temperature and the core temperature of the battery is 3.5 ° C. or less, and it can be seen that the battery has a feature that it is difficult to store heat.

  FIG. 10 is a graph showing the difference between the battery internal temperature after charging and the room temperature using the charging rate as a parameter. That is, in FIG. 10, the vertical axis indicates the temperature difference in degrees Celsius, and the horizontal axis indicates the elapsed time in minutes. It can be seen that at a charge rate of 2C or less, the difference (temperature rise) between the battery internal temperature and room temperature is 4 ° C. or less, which is very small. This seems to be because heat is not stored inside the battery because heat is released simultaneously with heat generated by charging.

In 5C charging and 8C charging, a difference between the battery internal temperature and room temperature is recognized. However, in less than 20 minutes, the difference between the battery internal temperature and room temperature has dropped below 5 ° C. It can be seen that the heat dissipation is extremely excellent.
From this test result, it was found that the laminated battery according to the present invention has a large thermal conductivity in the battery, and even if the temperature rises due to charging, the temperature inside the battery decreases in a short time.

  The laminated battery according to the present invention can be suitably used as a secondary battery not only for industrial use but also for consumer use.

10 Metal foil (a: positive electrode side, b: negative electrode side)
11 Cylindrical laminated battery 12 Cylindrical can (a: cylindrical can inner diameter, b: cylindrical can bottom, c: opening)
13 electrode body (a: positive electrode, aa: positive electrode inner diameter, ab: positive electrode outer diameter,
b: negative electrode, ba: negative electrode inner diameter, bb: negative electrode outer diameter,
c: Separator)
14 Insulating plate 15 Exterior body 16 Lid member 17 Current collector (a: rod-shaped shaft portion, b: stopper portion, c: screw portion, d: positive electrode terminal)
18 Bearing 20 Metal foil 3
21 Protrusion 25 Second metal foil 30 Metal foil 4 (h1: metal foil thickness, h2: structure thickness, h3: cache size,
L1: structure upper part, L2: structure lower part, P: structure pitch)
31 Projection 32 Opening 33 Snap 34 Lower edge 41, 51, 61, 71 Root 62, 72 Hole 73 Open

In order to achieve the above-described problems, a laminated battery according to the present invention is a battery in which a positive electrode and a negative electrode are laminated in the axial direction of the outer casing through a separator inside a cylindrical outer casing. The conductive current collector passes through the positive electrode, the negative electrode, and the separator in the axial direction of the outer package, and either the positive electrode or the negative electrode is connected to the outer package. a first electrode which is electrically connected, a second electrode and the other electrode not electrically connected to the outer body, and the second electrodes via the second metal foil It is electrically connected to the current collector, and the first electrode is not electrically connected to the current collector.

Stacked battery according to the present invention, on at least one surface of the front Stories second metal foil preferably has a plurality of projections.
According to this configuration, these metal foils are three-dimensionally processed so as to have a large number of protrusions formed so as to protrude on the surface thereof. As the secondary battery is charged / discharged, the volume of the electrode changes, but the protrusions provided on the metal foil deteriorate the contact between the first electrode and the exterior body and between the second electrode and the current collector. Makes it possible to prevent. The cycle life characteristics of the battery can be improved.

Stacked battery according to the present invention, the protrusion front SL provided on the second metal foil, it is preferable that the area of the bottom portion is larger frustum than the area of the top.
According to this configuration, protrusions can be formed by providing irregularities on the surface of the metal foil. In this case, protrusions are formed on both surfaces of the metal foil. If attention is paid to the convex and concave portions of the metal foil, the shape thereof becomes a frustum shape. Specifically, it is a polygonal frustum or a truncated cone. The area of the protrusion (top) of the protrusion is smaller than the area of the bottom of the protrusion, and the longitudinal section thereof is trapezoidal. The electrode bites into the frustum-shaped protrusion, and effectively works to keep good contact between the first electrode and the outer package and between the second electrode and the current collector. Since the area of the bottom is larger than the area of the top, the electrode stably bites into the protrusion of the metal foil.

Stacked battery according to the present invention, it is preferable that the tip portion of the projection provided on prior Symbol second metal foil is bent in the direction opposite to the protrusion.
According to this configuration, the metal foil has a “cache” in which the tip of the protrusion is bent in the direction opposite to the protrusion. This bite causes the electrode to bite and catch, thereby ensuring contact between the first electrode and the exterior body and between the second electrode and the current collector regardless of the expansion and contraction of the electrode accompanying charging and discharging.

Stacked battery according to the present invention, prior SL have holes provided at the distal end portion of the projection provided on the second metal foil preferably has an outer edge that projects outwardly from the periphery of the hole.
According to this configuration, it is possible to easily provide a cache at the tip or top of the protrusion.

In the laminated battery according to the present invention, the outer edge of the separator is covered with the first electrode, the outer edge of the second electrode is covered with the separator, and the current collector of the first electrode penetrates. periphery of the hole is covered by the separator, the peripheral edge of the hole through the collector of the separator that is covered by the second electrode.

Stacked battery according to the present invention, the current collector is not preferable to have a pipe-like side.
In this configuration, part or all of the side part of the current collector is covered with the pipe, so when the connection between the current collector and the electrode is loose, the pipe part of the current collector is connected to the inner diameter of the pipe. By driving a slightly larger pile, the outer diameter of the current collector can be increased. Thereby, the coupling | bonding of a collector and an electrode can be strengthened.

Stacked battery according to the present invention, it is not preferable that slits the axial direction of the pipe-shaped sides of the current collector is provided.
According to this configuration, when a pile slightly larger than the inner diameter of the pipe is driven into the pipe portion of the current collector, the slit is widened. Thereby, the outer diameter of the current collector can be widened with a small resistance, and the coupling between the current collector and the electrode can be tightened. If there is no slit in the pipe portion of the current collector, the outer diameter of the current collector is difficult to expand when a pile is driven into the current collector if the current collector is thick. When the wall thickness is thin, the electrical conductivity of the current collector becomes poor.

Stacked battery according to the present invention, the side surface of the current collector is not preferable to have an irregular shape.
According to this configuration, the current collector has an uneven shape on the side surface. The diameter of the hole through which the current collector provided in the second electrode passes is smaller than the sum of the concave diameter of the current collector and the thickness of the second metal foil. Thereby, even if the volume of the electrode changes with charge / discharge, it becomes possible to ensure sufficient contact between the second electrode and the current collector by the anchor effect due to the uneven shape. Examples of the method for providing the uneven shape include existing methods such as etching, knurling, knurling, embossing, screwing, and laser processing.

In the laminated battery according to the present invention, a groove is formed on a side surface of the current collector, and a sum of a groove trough diameter of the current collector and a thickness of the second metal foil is applied to the second electrode. The diameter of the groove of the current collector and the sum of the thickness of the second metal foil are larger than the diameter of the hole through which the current collector is provided, and the current collector provided in the first electrode penetrates. it is not preferable smaller than the diameter of holes.
According to this configuration, the groove provided on the side surface of the current collector is preferably a screw groove. The groove valley is the thinnest part of the current collector. The second electrode is in close contact with the screw groove via the second metal foil. Groove mountain is the thickest part of the current collector. The first electrode is not in contact with the current collector.

Stacked battery according to the present invention, the charge capacity of the negative electrode is not preferable to be less than the charge capacity of the positive electrode. Generally, in an alkaline secondary battery, positive electrode regulation is adopted for sealing, and a larger negative electrode capacity is required than a positive electrode capacity. However, the laminated battery is a so-called negative electrode regulation. Here, each charge capacity may be simply referred to as a positive electrode capacity or a negative electrode capacity.

Stacked battery according to the present invention, the inside of the exterior body, it is not preferable that includes a hydrogen storage chamber for storing hydrogen gas generated at the negative electrode. In this configuration, the hydrogen storage chamber may be an independent space. Further, the hydrogen storage chamber is not an independent space but may be a gap between electrodes or separators. In fact, hydrogen can be stored between the positive electrode active material or the hydrogen storage alloy.

Stacked battery according to the present invention, it is not preferable to charge the hydrogen storage alloy contained by using hydrogen gas stored in the hydrogen storage chamber to the negative electrode. According to this configuration, the hydrogen gas generated by overcharging is used effectively by charging the negative electrode. The hydrogen storage alloy contained in the negative electrode functions as a catalyst.

In the method for assembling the laminated battery according to the present invention, a round bar slightly smaller than the inner diameter of the second electrode is projected at the center of a cylinder having an inner diameter slightly larger than the outer diameter of the first electrode , and the round bar is in contact with the first electrode . After sequentially inserting the separator so that the separator is interposed between one electrode and the second electrode and stacking the electrodes, the electrode group stacked from the cylinder and the round bar are taken out integrally, and the outer periphery of the first electrode is A first metal foil is affixed, first electrodes adjacent in the axial direction are electrically connected, the round bar is extracted from the electrode group, and a second metal foil is affixed to the inner periphery of the second electrode The electrode group on which the first and second metal foils are pasted is press-fitted into the exterior body, the current collector having a larger inner diameter than the second electrode is press-fitted into the electrode group, and air is vented. It injects the liquid.
According to this assembling method, the electrode assembly is press-fitted into an exterior body composed of a cylindrical can with a bottom, and after the electrolyte is injected, the cylindrical can is sealed with the lid member to seal the battery.

10 Metal foil (a: positive electrode side, b: negative electrode side)
11 Cylindrical laminated battery 12 Cylindrical can (a: cylindrical can inner diameter, b: cylindrical can bottom, c: opening)
13 electrode body (a: positive electrode, aa: positive electrode inner diameter, ab: positive electrode outer diameter,
b: negative electrode, ba: negative electrode inner diameter, bb: negative electrode outer diameter,
c: Separator)
14 Insulating plate 15 Exterior body 16 Lid member 17 Current collector (a: rod-shaped shaft portion, b: stopper portion, c: screw portion, d: positive electrode terminal)
18 Bearing 20 Metal foil 3
21 Protrusion 25 Second metal foil 30 Metal foil 4 (h1: metal foil thickness, h2: structure thickness, h3: cache size,
L1: structure upper part, L2: structure lower part, P: structure pitch)
31 Protrusion 32 Opening 33 Root 41, 51, 61, 71 Protrusion 62, 72 Hole 73 Opening

Claims (15)

A battery in which a positive electrode and a negative electrode are laminated in the axial direction of the outer casing through a separator inside a cylindrical outer casing,
A conductive current collector passes through the positive electrode, the negative electrode, and the separator in the axial direction of the exterior body,
Either the positive electrode or the negative electrode is a first electrode electrically connected to the exterior body via a first metal foil, and the other electrode is electrically connected to the exterior body. No second electrode, and
A laminated battery in which the second electrode is electrically connected to the current collector through a second metal foil, and the first electrode is not electrically connected to the current collector.   The multilayer battery according to claim 1, wherein a plurality of protrusions are provided on at least one surface of the first metal foil or the second metal foil.   The laminated battery according to claim 2, wherein the protrusion provided on the first metal foil or the second metal foil has a frustum shape in which the area of the bottom is larger than the area of the top.   4. The laminated battery according to claim 2, wherein a tip portion of the protrusion provided on the first metal foil or the second metal foil is bent in a direction opposite to the protrusion. 5.   The hole is provided in the front-end | tip part of the said protrusion provided in the said 1st metal foil or the 2nd metal foil, and it has an outer edge which protrudes outward from the periphery of the said hole. The laminated battery described in 1.   The outer edge of the separator is covered with the first electrode, the outer edge of the second electrode is covered with the separator, and the periphery of the hole through which the current collector of the first electrode passes is covered with the separator. 3. The stacked battery according to claim 1, wherein a peripheral edge of a hole penetrating the current collector of the separator is covered with the second electrode.   The laminated battery according to claim 1, wherein the current collector has a pipe-like side portion.   The laminated battery according to claim 7, wherein a slit is provided in an axial direction of the pipe-like side portion of the current collector.   The laminated battery according to claim 1, wherein a side surface of the current collector has an uneven shape.   Groove processing is applied to the side surface of the current collector, and the sum of the groove trough diameter and the thickness of the second metal foil passes through the current collector provided in the second electrode. A sum of a groove crest diameter of the current collector and a thickness of the second metal foil is smaller than a diameter of a hole penetrating the current collector provided in the first electrode. 1. The laminated battery according to 1.   The laminated battery according to claim 1, wherein the negative electrode includes a hydrogen storage alloy.   The laminated battery according to claim 11, wherein a charge capacity of the negative electrode is smaller than a charge capacity of the positive electrode.   The laminated battery according to claim 12, further comprising a hydrogen storage chamber for storing hydrogen gas generated at the negative electrode inside the outer package.   The laminated battery according to claim 13, wherein the hydrogen storage alloy contained in the negative electrode is charged using hydrogen gas stored in the hydrogen storage chamber. A round bar slightly smaller than the inner diameter of the negative electrode is protruded from the center of the cylinder whose inner diameter is slightly larger than the outer diameter of the positive electrode, and sequentially inserted so that the separator is interposed between the positive electrode and the negative electrode. After the electrodes are stacked, the electrode group stacked from the cylinder and the round bar are integrally taken out, the first metal foil is attached to the outer periphery of the positive electrode, and the positive electrodes adjacent in the axial direction are electrically connected to each other. The round bar is extracted from the electrode group, a second metal foil is attached to the inner periphery of the negative electrode, the electrode group to which the first and second metal foils are attached is press-fitted into the exterior body, A method for assembling a laminated battery, in which the current collector larger than the inner diameter of the negative electrode is press-fitted into the electrode group, air is vented, and an electrolytic solution is injected.