JP2005285514A - Cylindrical battery and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cylindrical battery having a current collector realizing high joining strength between an electrode body and an outer jacket, low electric resistance, and the uniformity of reaction in use of the battery, and to provide the manufacturing method of the battery. <P>SOLUTION: The cylindrical battery 1 has winding structure, an electrode body 20 in which a winding core part 20h is hollow, the outer jacket 10 in which the electrode body 20 is housed, and a current collector 42 inserted between the inside bottom of the outer jacket 10 and the electrode body 20 to electrically connect them. When an extension region in which a winding core part 10h of the electrode body 10 is extended in the winding axis direction is imagined, an overlapped region of the extension region and the current collector 42 is decided as the central region 42a of the current collector 42, and a region other than the central region 42a in the current collector 42 is decided as an outer peripheral region 42b, the current collector 42 is joined to the inner bottom of the outer jacket 10 in a plurality of portions 42p, and at least one portion of the plurality of portions 42p is located in the outer peripheral region 42b. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a cylindrical battery and a manufacturing method thereof, and more particularly to a technique for reducing battery resistance related to a current collector.

  Cylindrical batteries have been conventionally used as a power source for various portable devices, but in recent years, they have also been developed as a power source for hybrid electric vehicles (HEVs) and electric vehicles (Pure-Electric Vehicles). It is being advanced. In a cylindrical battery, an electrode body in which a positive electrode plate and a negative electrode plate are wound via a separator is housed in a bottomed cylindrical exterior body, and after injecting an electrolytic solution, a lid body is formed at the opening of the exterior body. Is placed and sealed. The outer body, the lid, and the electrode body are electrically joined by interposing a thin disk-shaped current collector (see Patent Document 1 and Patent Document 2).

The shape of the current collector used in the conventional cylindrical battery and the method of connecting the current collector and the exterior body will be described with reference to FIG. Hereinafter, the current collector disposed on the bottom side of the can will be described.
As shown in FIG. 7 (a), the current collector 142 is a thin plate having a substantially circular shape, and a U-shaped notch 142s is provided at the center thereof, thereby forming a tongue 142a. Yes. Further, a burring portion 142w is formed in the exterior body 110 toward the electrode body 120 in a substantially entire region on the surface of the current collector 142.

  As shown in FIG. 7B, current collectors are bonded to both end surfaces of the electrode body 120 housed in the exterior body 110. Among these, the above-described current collector 142 is joined to the lower end surface of the electrode body 120 on the can bottom side. Thus, the electrode body 120 in which the current collector is bonded to the both end faces is housed in the exterior body 110, and the welding electrode 501 is contacted with the current collector 142 from the winding core portion 120 h of the electrode body 120. insert.

In order to join the current collector 142 to the bottom of the can body 110, a current F is applied to the welding electrode 501 while applying a force F so that there is no gap between the current collector 142 and the exterior body 110. Thus, the lower surface of the tongue 142a of the current collector 142 and the inner surface of the exterior body 110 are joined.
By the way, when the current collector 142 as shown in FIG. 7 is used, the joint portion between the current collector 142 and the can bottom of the exterior body 110 becomes one portion of the tongue 142a, and the electric (battery) resistance and the joint strength are obtained. It has a problem from the point of view. Further, in the conventional battery shown in FIG. 7, the junction between the current collector 142 and the exterior body 110 is one place in the center, and therefore, an uneven reaction due to current concentration occurs when the battery is used. Battery life is shortened. Therefore, Patent Document 3 attempts to solve the above problem by providing a plurality of projections on the side surface of the current collector that is joined to the exterior body and joining the exterior body with the plurality of projections.
Japanese Utility Model Publication No. 57-014968 Japanese Utility Model Publication No. 61-194959 Japanese Patent Laid-Open No. 06-275253

  However, in the cylindrical battery of Patent Document 3, a plurality of protrusions are provided on the current collector, and the plurality of protrusions are connected to the exterior body. However, the plurality of protrusions on the current collector are connected to the current collector. Therefore, there remains a problem that a high electrical resistance between the current collector and the outer package after joining and non-uniform reaction due to current concentration when the battery is used. Therefore, the cylindrical battery of Patent Document 3 has problems that the battery performance is low and the battery life is short.

  The present invention has been made to solve such problems, and ensures high electrical resistance between the current collector and the exterior body, high joint strength, and high uniformity of reaction during battery use. It is an object of the present invention to provide a cylindrical battery that can be manufactured and a method for manufacturing the same.

In order to achieve the above object, the present invention has the following characteristics.
(1) An electrode body in which positive and negative bipolar plates are wound through a separator and a winding core portion is hollow, and a bottomed cylindrical body made of a conductive material, and an exterior body that houses the electrode body, A cylindrical battery made of a conductive material and having a current collector interposed between the inner bottom of the exterior body and the electrode body, the winding core portion of the electrode body being wound Assuming an extended area extending in the direction of the rotation axis, the overlapping area between the extended area and the current collector is the central area of the current collector, and the area excluding the central area of the current collector is the outer edge area. The body is bonded to the inner bottom of the exterior body at a plurality of locations, and at least one of the plurality of locations exists in the outer edge region.

(2) In the cylindrical battery according to (1) above, the current collector has a plurality of protrusions formed on the outer edge portion toward the inner bottom of the exterior body, and the tip regions of the plurality of protrusions are It is joined to the inner bottom of the exterior body.
(3) In the cylindrical battery according to the above (2), the plurality of protrusions are arranged at substantially equal distances from the center of the winding axis of the electrode body.

(4) The cylindrical battery according to any one of (1) to (3), wherein an insulator is interposed between the current collector in the central region and the inner bottom of the exterior body. It is characterized by.
(5) The cylindrical battery according to any one of (2) to (4), wherein the electrode body and the current collector are a junction and a positive electrode formed toward the electrode body side in the current collector. It is joined with the end surface of a board or a negative electrode board, and the projection part is formed in the position which does not overlap with a junction part in the radial direction of the said electrode body.

(6) A method for manufacturing a cylindrical battery, comprising the following steps.
* Electrode body forming step: The positive and negative bipolar plates are opposed to each other with a separator interposed therebetween, and the electrode body having a hollow winding core portion is formed by winding in this state.
* Current collector joining step: A current collector made of a conductive material is joined to at least one end surface of the electrode body in the winding axis direction.

* Storage step: The electrode body to which the current collector is bonded is housed in a bottomed cylindrical exterior body made of a conductive material with the current collector side facing the inner bottom.
* Joining step: Joining the current collector to the inner bottom of the outer package.
Here, assuming an extension region in which the winding core portion of the electrode body is extended in the winding axis direction, the overlapping region of the extension region and the current collector is a central region of the current collector, and the central region in the current collector In the joining step, the current collector is joined to the inner bottom of the exterior body at a plurality of locations, and at least one of the plurality of locations is located in the outer edge region. It is characterized by.

(7) The method for manufacturing a cylindrical battery according to (6), wherein the plurality of protrusions are arranged at substantially equal distances from the center of the winding axis of the electrode body.
(8) In the method for manufacturing the cylindrical battery according to (6) or (7), an insulator is interposed between the current collector and the inner bottom of the exterior body in the central region. It is characterized by that.
(9) A method for manufacturing a cylindrical battery according to any one of (6) to (8) above, wherein, in the joining step, the current collector and the inner bottom of the exterior body are joined using a resistance welding method. It is characterized by doing.

  In the cylindrical battery according to the present invention, the current collector and the inner bottom of the exterior body are joined at a plurality of locations including at least one location of the outer edge region. The exterior body is surely joined at a plurality of locations, and has advantages such as low electrical resistance, high joint strength, and high uniformity of reaction due to current dispersion when the battery is used. Such superiority of the present invention will be described in comparison with the cylindrical battery according to Patent Document 3.

  In the cylindrical battery of Patent Document 3, the plurality of protrusions are concentrated in the center of the current collector, that is, directly below and in the vicinity of the portion where the welding electrode contacts when the current collector and the exterior body are joined. Is provided. For this reason, although the current collector and the exterior body are connected by a plurality of protrusions, they are joined only in a narrow region of the central region. For this reason, in the cylindrical battery of Patent Document 3 described above, the electrical resistance between the current collector and the exterior body is high, and the joints are concentrated in the central region. Reaction concentrates on the winding core part of the electrode body, and the battery life is short.

  On the other hand, in the cylindrical battery according to the present invention, the current collector and the exterior body are joined at a plurality of locations including at least one location of the outer edge region, so that they are reliably joined at a plurality of locations. It will be. Therefore, a low electrical resistance between the current collector and the exterior body is realized, and current concentration does not occur when the battery is used. In the cylindrical battery according to the present invention, nonuniform reaction due to current concentration is unlikely to occur during use. Further, in the outgoing cylindrical battery according to the present invention, since the current collector and the exterior body are joined at a plurality of locations, a high joint strength between them is ensured as compared with the conventional cylindrical battery shown in FIG. Is done.

Therefore, the cylindrical battery according to the present invention ensures high bonding strength and low electrical resistance between the current collector and the exterior body, and high uniformity of reaction when the battery is used.
In the cylindrical battery according to the present invention, even when a pressing force is applied between the current collector and the exterior body during manufacturing, the gap between the current collector and the exterior body in the central region is more sure. Therefore, it is desirable to interpose an insulator between the current collector in this region and the inner bottom of the exterior body.

Moreover, in the cylindrical battery according to the present invention, it is desirable to provide a plurality of joints in the outer edge region, but in that case, the plurality of joints in the outer edge region are not necessarily present separately. There is no need. For example, even if the joining portions continuously form a ring shape, they are included in the configuration of the cylindrical battery in the present invention.
The method for manufacturing a cylindrical battery according to the present invention includes a current collector and an exterior body using a plurality of locations including at least one location located in an outer edge region of the current collector joined to an end surface of the electrode body in the winding axis direction. Therefore, low electrical resistance and high welding strength between the current collector and the exterior body can be realized as described above. In addition, in the cylindrical battery manufactured using this method, at least one of the plurality of joints is disposed in the outer edge region, so that current does not concentrate in the central region when the battery is used. The uniformity of the reaction due to current dispersion can be kept high.

  Therefore, in the method for manufacturing a cylindrical battery according to the present invention, it is easy to obtain a cylindrical battery in which high bonding strength and low electrical resistance between the current collector and the exterior body and high uniformity of reaction during battery use are ensured. Can be manufactured.

(Embodiment 1)
In the following, the best mode for carrying out the invention will be described by taking a cylindrical nickel-hydrogen sealed secondary battery (hereinafter simply referred to as “battery”) 1 as an example with reference to the drawings. The battery 1 described below is used as an example for explaining the configuration, operation, and effect of the present invention, and the present invention is not limited thereto.
(Overall configuration of battery 1)
The structure of the battery 1 according to the embodiment of the present invention will be described with reference to FIG.

  As shown in FIG. 1, the battery 1 includes a spirally-shaped electrode body 20 in which the positive and negative current collectors 41 and 42 are joined to the upper and lower ends, and It is housed and configured inside. And the upper opening part in the exterior body 10 has the structure sealed with the sealing cover 30. FIG. In addition, a film body (not shown) attached between the outer peripheral surface of the electrode body 20 and the inner wall surface of the exterior body 30 for the purpose of preventing (binding) the electrode body 20 from being loosened or wounded. Is inserted.

As shown in FIG. 1, among the elements constituting the battery 1, the electrode body 20 is disposed so as to face each other with a positive electrode plate 21 and a negative electrode plate 22 sandwiching a separator 23 therebetween. The wound core part is hollow and is hollow.
Among the constituent elements of the electrode body 20, the positive electrode plate 21 is formed, for example, by forming a nickel sintered porous body on the surface of a core body made of punching metal, and then using a chemical impregnation method on the inside of the nickel sintered porous body. It is produced by filling an active material mainly composed of nickel oxide. The negative electrode plate 22 is produced, for example, by using a punching metal as a core, filling the surface of the core with a paste-like active material made of a hydrogen storage alloy, drying, and rolling to a predetermined thickness. It is what is done.

The positive and negative current collectors 41 and 42 are mainly composed of thin metal discs, and include the electrode portion of the sealing lid 30 and the positive electrode plate 21, the can bottom portion 10B of the outer package 10, the negative electrode plate 22, It is intended to achieve a good electrical connection between each of the above.
The exterior body 10 is a bottomed cylindrical body made of a metal material, and the inner diameter thereof is set substantially equal to the outer diameter of the electrode body 20. An insulating member 50 is interposed between the exterior body 10 and the negative electrode current collector 42 at the radial center portion of the can bottom portion 10B of the exterior body 10.

As described above, the sealing lid 30 is placed on the opening of the exterior body 10, and the edge portion is crimped with a gasket interposed therebetween. The sealing lid 30 is provided with a gas venting mechanism at the time when the battery internal pressure rises, but since this is a known one, the description thereof is omitted here.
In addition to the electrode body 20, the positive and negative current collectors 41 and 42, and the insulating member 50, for example, an electrolytic solution made of a 30 (mass%) potassium hydroxide aqueous solution is injected into the exterior of the exterior body 10. (Not shown).
(Detailed structure of battery 1 in can bottom portion 10B)
Next, the structure around the can bottom portion 10B which is the most characteristic part of the present embodiment in the configuration of the battery 1 will be described with reference to FIG.

  As shown in FIG. 2, in the electrode body 20 housed inside the exterior body 10, the winding core portion 20h is hollow as described above. A separator 23 is disposed on the inner wall surface 20a of the electrode body 20 facing the winding core portion 20h. The negative electrode plate 22 of the electrode body 20 is in a state where the core body 22a extends downward in the Z direction, and the end face of the core body 22a is joined to the negative electrode current collector 42. Yes. Specifically, the negative electrode current collector 42 is formed with a plurality of burring portions 42 w upward in the Z direction. The burring portion 42 w is provided as a joint with the negative electrode plate 22, and a part thereof is joined to the end surface of the core body 22 a in the negative electrode plate 22. Here, the negative electrode current collector 42 is made of a conductive material such as Ni plating SPCE.

Further, as described above, the insulating member 50 is interposed between the negative electrode current collector 42 and the exterior body 10, and the installation region in the X direction of the insulating member 50 is as follows. .
In a state where the negative electrode current collector 42 is bonded to the electrode body 20, a region in which the winding core portion 20 h is extended in the winding direction (Z direction) is assumed, and the extended region and the negative electrode current collector 42 overlap each other. When the region is assumed to be the central region 42a of the negative electrode current collector 42, the insulating member 50 is on the bottom side (lower side in the Z direction) of the negative electrode current collector 42 and is slightly larger in the radial direction than the central region 42a. Set to size.

  In addition, when the region excluding the central region in the negative electrode current collector 42 is defined as the outer edge region 42b, the negative electrode current collector 42 includes the tip portion of the projection (projection) portion 42p provided in the outer edge region 42b and It is joined to the exterior body 10 in the vicinity. In addition, the Z direction height in the protrusion part 42p is set to a dimension a little larger than the Z direction dimension (thickness) of the insulating member 50. FIG.

Note that the number of protrusions 42p formed on the negative electrode current collector 42 may be two or more, but in this embodiment, the number is four as an example.
(Superiority of battery 1)
As described above, in the battery 1, the negative electrode current collector 42 housed in the can bottom of the outer package 10 is joined to the outer package 10 by the plurality of protrusions 42 p formed on the outer edge portion 42 b. 7 is superior to the conventional battery of FIG. 7 in which the electric body 142 is bonded to the exterior body 110 only by the tongue 142a. Further, in the battery 1 according to the present embodiment, since the negative electrode current collector 42 and the exterior body 10 are joined with the plurality of protrusions 42p existing in the outer edge region 42b, a low electrical resistance therebetween is realized. In addition, when the battery is used, the uniformity of the reaction is improved by the dispersion of the conductive path.

In addition, about the battery of the said patent document 3, although several protrusion part is formed in the electrical power collector, as above-mentioned, several protrusion part is concentrated and arrange | positioned at the center area | region of an electrical power collector. Therefore, the battery resistance is high, and when the battery is used, non-uniform reaction occurs due to current concentration. Therefore, the battery 1 according to the present embodiment has the above advantages over the battery according to Patent Document 3.
(Method for manufacturing battery 1)
A method for manufacturing the battery 1 will be described with reference to FIGS.

1. As shown in FIG. 3, the positive electrode current collector 41 is bonded to the upper end surface of the spirally wound electrode body 20 as shown in FIG. The negative electrode current collector 42 is bonded to the end face. In the present embodiment, the current collector plates 41 and 42 are joined to the end face of the electrode body 20 using a resistance welding method. In this connection, in addition to the resistance welding method, a laser beam welding method, an electron beam welding method, or the like can be used. In this case, the burring portion 42w need not be formed.

An insulating member 50 is bonded to the main surface of the negative electrode current collector 42 opposite to the bonding surface to the electrode body 20.
The electrode body 20 is formed by facing and arranging a positive electrode plate 21 and a negative electrode plate 22 with a separator 23 interposed therebetween, and is wound, and the winding core portion 20h is hollow. ing. And the edge part of the positive electrode plate 21 is exposed from the upper part of FIG. 3 of the electrode body 20, and the edge part of the negative electrode plate 22 is exposed from the downward direction.

  The positive electrode current collector 41 is formed by connecting a pipe-like connecting body 41a having an elliptical cross section to a circular plate. The plate body of the positive electrode current collector 41 has a plurality of burring portions 41 w formed downward in FIG. 3, that is, toward the electrode body 20. The pipe-shaped connecting body 41a is formed with a hole 41h having the same diameter as or slightly larger than the winding core portion 20h of the electrode body 20, and the subsequent hole is also formed in the plate body (not shown). (Illustrated).

As shown in FIG. 4A, the negative electrode current collector 42 is formed with a plurality of burring portions 42w and four protrusions 42p. As shown in FIG. 4B, the plurality of burring portions 42w are formed by punching the opening 42w1 by the edge 42w2 projecting in a burr shape, with the main surface of the negative electrode current collector 42 punched toward the electrode body 20 side. It is formed so as to surround it.
As shown in FIG. 4A, the four protrusions 42p are formed in the outer edge region 42b of the negative electrode current collector 42, and are on the same circumference with the winding axis of the electrode body 20 as the center. It is arranged in. As shown in FIG. 4C, the protrusion 42 p is formed by projecting the negative electrode current collector 42 toward the can bottom portion 10 </ b> B of the outer package 10. In addition, as for the formation of the protrusion 42p, the number of the protrusions 42p is not necessarily four, but from the viewpoint of ensuring the uniformity of current collection, the position is preferably the outer edge portion 42b. It is desirable to equidistant from the 20 winding axes.

  The insulating member 50 is set to a size slightly larger than the central region 42a of the negative electrode current collector 42, and is bonded so as to cover the entire central region 42a on the back surface of the main surface to which the electrode body 20 is bonded. For the insulating member 50, it is necessary to use a material that is chemically stable with respect to the electrolytic solution. For example, organic materials such as polypropylene (PP), polyethylene (PE), and PTFE (polytetrafluoroethylene), alumina It is possible to use ceramic materials such as

The insulating member 50 needs to have a thickness smaller than the height of the protrusion 42p of the negative electrode current collector 42.
In this way, the joining of the current collectors 41 and 42 to the electrode body 20 is completed.
2. Joining of Negative Electrode Current Collector 42 and Can Bottom Portion 10B of Exterior Body 10 Next, a joining method of the negative electrode current collector 42 joined to the electrode body 20 and the exterior body 10 will be described with reference to FIG.

As shown in FIG. 5A, the electrode body 20 in which the current collectors 41 and 42 and the insulating member 50 are joined is housed inside the bottomed cylindrical exterior body 20. At this time, there is a gap between the insulating member 50 and the inner bottom surface of the can bottom portion 10B of the outer package 10, and the inner bottom surface of the can bottom portion 10B has a protrusion 42p of the negative electrode current collector 42. The tip is in contact.
After the electrode body 20 is stored, the welding electrode 501 is inserted through the winding core portion 20 h of the electrode body 20, and one end thereof is brought into contact with the central region 42 a of the negative electrode current collector 42. Then, a required pressure F ₁ is applied between the outer package 10 and the welding electrode 501 in the penetration direction of the welding electrode 501. Then, the tip of the protrusion 42p of the negative electrode current collector 42 and its peripheral portion are welded to the can bottom portion 10B of the outer package 10 by flowing the welding current I ₀ for a certain time while maintaining the pressurized state. Here, at the time of pressurization of the welding electrode 501, a pressure F is applied to the outer bottom surface of the positive electrode current collector 41 toward the can bottom portion 10 </ b> B simultaneously with a pressurizing member (for example, an elastic member such as rubber). Multiply ₂ . This is for ensuring that the negative electrode current collector 42 and the inner bottom of the can bottom portion 10B of the outer package 10 are in close contact with each other. Here, the applied pressure F ₁ and the applied pressure F ₂ are not necessarily the same.

The welding conditions are, for example, as shown below.
SQD (Time to start energization in pressurized state): 100 (msec.)
WE (energization time): 8 (msec.)
UP SLOPE (Time to rise of current value): 4 (msec.)
HEAT (energization current): 12 (kA)
When the welding current I ₀ is passed from the welding electrode 501 in this way, the current in the negative electrode current collector 42 is branched into four protrusions 42p as shown in FIG. The current I ₁ flows between the portion 42p and the can bottom portion 10B of the outer package 10. And since the insulating member 50 is interposed between the back surface of the portion where the tip portion of the welding electrode 501 contacts the negative electrode current collector 42 and the inner bottom surface of the bottom surface portion 10B of the exterior body 10, Even when welding is performed with the applied pressure F ₁ , the welding current I ₀ does not flow in the central region 42 a (see FIG. 2) of the negative electrode current collector 42.

As described above, the joining of the outer package 10 and the negative electrode current collector 42 is completed. Although not shown, after that, a required amount of electrolyte is injected into the exterior of the exterior body 10, and the opening portion of the exterior body 10 is sealed with the sealing lid 30 to complete the battery 1.
(Modification)
Next, a battery according to a modification will be described with reference to FIG. 5B with a focus on differences from the battery 1 according to the above embodiment.

As shown in FIG. 5B, in the battery according to this modification, unlike the battery 1 according to the above embodiment, an insulation distance is provided between the negative electrode current collector 42 and the exterior body 10. In the meantime, an insulating member is not interposed. That is, in the manufacturing process of the battery according to the modified example, when the central region C of the negative electrode current collector 42 is applied with the welding electrode 501 when the negative electrode current collector 42 and the exterior body 10 are joined, In the central region C, the probability of leakage of the welding current I ₀ between the negative electrode current collector 42 and the outer package 10 is higher than that in the case of the battery 1.

However, also in the battery according to the modified example, the welding strength and electrical resistance between the negative electrode current collector 42 and the exterior body 10 are compared with the battery having the conventional configuration as shown in FIG. It is excellent from both viewpoints. That is, even in the manufacturing process of the battery according to this modification, it is possible to prevent the leakage of the welding current I ₀ in the central region C by optimizing the applied pressures F ₁ and F ₂ and other welding conditions. The current I ₀ can be distributed to each protrusion 42p. Thereby, the same effect as the battery 1 according to the above embodiment can be obtained.

Further, in the battery according to this modification, the cost is superior to the battery 1 according to the above-described embodiment in terms of material cost, man-hours, etc., as much as the insulating member is omitted.
In this modification, the plurality of protrusions 42p are arranged in the outer edge region of the negative electrode current collector 42. However, the arrangement of the protrusions 42p does not necessarily have to be the outer edge region. There may be a plurality of the protrusions 42p, and at least one of them may be present in the outer edge region.
(Experiment to confirm superiority)
Below, the experiment conducted in order to confirm the above superiority is demonstrated. In this experiment, each of the batteries of Examples 1 and 2 and Comparative Example having the following configurations was manufactured and evaluated for each 10 cells.
(Example 1)
The configuration of the battery according to Example 1 is the same as that of the battery 1 according to the above embodiment. And the member used for the structure of the battery which concerns on Example 1 is as follows.

Negative electrode current collector; Ni-plated SPCE (t = 0.4 mm)
Burring height: 0.6mm
Projection height: 0.4 mm
Insulating member; PP tape (t = 0.04mm)
Electrolyte: 30% (mass%) potassium hydroxide aqueous solution
Injection volume: 12 (ml)
The welding conditions between the negative electrode current collector and the exterior body are also the same as in the above embodiment.
(Example 2)
The configuration of the battery according to Example 2 differs from the battery of Example 1 only in that it does not have an insulating member. There is no change in other configurations.
(Comparative example)
The configuration of the battery according to the comparative example is the same as the configuration of the conventional battery shown in FIG. 7, and the negative electrode current collector has no protrusion and has a tongue in the central region.

The welding conditions for the negative electrode current collector and the outer package were as follows.
SQD (Time to start energization in pressurized state): 100 (msec.)
WE (energization time): 8 (msec.)
UP SLOPE (Time to rise of current value): 4 (msec.)
HEAT (energization current): 10 (kA)
(Evaluation methods)
First, the batteries according to Examples 1 and 2 and the comparative example are charged 6 (hr.) At 1200 (mAh), and then discharged to the final voltage 0.8 (V) with the same current value. This charge / discharge cycle was repeated 10 times at an ambient temperature of 25 (° C.).

  Next, as shown in FIG. 6, for each battery according to Examples 1 and 2 and the comparative example, a window portion 10 h is provided in the vicinity of the bottom of the can on the side wall of the exterior body, and each of the negative electrode current collector and the exterior body is provided. Voltage measurement leads 511 and 512 were attached. Thereafter, charging was performed on each battery at 30 (min.) At 3 (Ah) or 6 (A), and charging and discharging were repeated for each battery under the following conditions.

Charging / discharging conditions: 40 (A) discharging ⇒ 40 (A) charging ⇒ 80 (A) discharging ⇒ 80 (A) charging ⇒ 120 (A) discharging ⇒ 120 (A) charging ⇒ 160 (A) discharging ⇒ 160 (A) Charging In addition, a 10 (min.) Rest period is provided between each step, and after 10 (min.) Rest after each discharge step, discharging is performed every 10 (sec.). sec.) Each voltage value at the time of elapse was measured through the leads 511 and 512. And this value is plotted for every battery, battery resistance is calculated | required from the inclination, and the average value about the battery of each structure is shown in Table 1.

表１に示すように、比較例に係る電池の電池抵抗が平均で０．２８（ｍΩ）であったのに対して、実施例１、２の電池では、それぞれ０．１０、０．１４（ｍΩ）となった。これように、比較例に係る電池で電池抵抗が大きなものとなったのは、図７に示すように、負極集電体と外装体との接続ポイントが１箇所であるためと考えられる。これに対して、実施例１、２の電池の電池抵抗を比較例の電池に比べて１／２〜１／３に低減できたのは、負極集電体と外装体との接続ポイントが４箇所であるためと考えられる。

As shown in Table 1, the battery resistance of the battery according to the comparative example was 0.28 (mΩ) on the average, whereas in the batteries of Examples 1 and 2, 0.10 and 0.14 ( mΩ). As described above, the reason why the battery according to the comparative example has a large battery resistance is considered to be that there is one connection point between the negative electrode current collector and the exterior body as shown in FIG. On the other hand, the battery resistance of the batteries of Examples 1 and 2 was reduced to 1/2 to 1/3 of the battery of the comparative example because the connection point between the negative electrode current collector and the exterior body was 4 This is thought to be due to the location.

  When comparing Example 1 and Example 2, the battery resistance Min. The values were equal to each other at 0.08 (mΩ), whereas Max. The value of Example 1 was 0.10 (mΩ), and that of Example 2 was 0.18 (mΩ). This is probably because the battery of Example 2 did not include the PP tape as the insulating member, and thus the welded state at the time of welding between the negative electrode current collector and the exterior body varied. That is, it is considered that the probability of contact with the exterior body in the central region of the negative electrode current collector is increased during welding.

From the above results, the superiority of the battery 1 according to the above embodiment and the battery according to the modification was confirmed.
(Other matters)
In addition, about the said embodiment and modification, an example of this invention is shown, and this invention is not limited to these. For example, in the above-described embodiment and modification, Ni-MH battery is taken as an example of the battery type. However, if the battery has a cylindrical appearance and includes a spiral electrode body and a current collector, The present invention can be applied. Specifically, the present invention can be applied to Ni-Cd batteries, Li batteries, and the like.

In addition, since the battery according to the embodiment and the modification has a configuration in which the negative electrode current collector is disposed on the can bottom side of the outer package 10, a plurality of protrusions 42p are formed on the negative electrode current collector 42. However, when the positive electrode current collector is arranged at the same position, the protrusion 42p may be provided on the positive electrode current collector.
The present invention is not limited to the above-described embodiments and modifications in terms of the number of protrusions 42p and the positions where they are formed, including a plurality of locations (including those that are continuous in a ring shape). However, in order to ensure high weldability during welding of the current collector 42 and the exterior body 10, a plurality of protrusions 42p are provided at the same distance from the center of the central region 42a of the current collector 42. Is desirable.

Further, the shape of the current collector 42 is a substantially disc shape in the above embodiment, but may be a polygonal shape or a cross shape.
Further, since the exterior body 10 is required to have a sealing property, the current collector 42 is not required to have a sealing property. Therefore, the protrusion 42p is provided on the side of the current collector 42. However, conversely, the same effect as described above can be obtained even when a protrusion is provided on the inner bottom surface side of the can bottom portion 10B of the outer package 10.

Moreover, you may decide to provide a U-shaped notch around the junction part in the electrical power collector 42, for example.
Furthermore, the present invention can also be applied to a primary battery in the case of the configuration including the spiral electrode body 20 and the current collector 42 as in the battery 1 described above.

  INDUSTRIAL APPLICABILITY The present invention is useful for realizing a cylindrical battery that requires high power generation efficiency even in applications that require a large current output such as HEV.

1 is a perspective view (partially sectional view) showing a cylindrical battery 1 according to an embodiment. 2 is a cross-sectional view showing a detailed configuration of a bottom portion of an exterior body 10 in the cylindrical battery 1. FIG. 3 is a developed perspective view showing a positional relationship between an electrode body 20 and current collectors 41 and 42 built in the cylindrical battery 1. FIG. It is the top view (a) which shows the structure of the negative electrode collector 42, and detailed sectional drawing (b), (c). FIG. 6 is a schematic cross-sectional view showing a joining step between a negative electrode current collector 42 and an exterior body. It is a schematic cross section which shows the connection form of the leads 511 and 512 given for the potential difference measurement in the confirmation experiment. It is the top view (a) of the negative electrode collector 142 used for the conventional cylindrical battery, and a schematic cross section (b) which shows the connection step of the negative electrode collector 142 and the exterior body 110.

Explanation of symbols

1. Cylindrical battery 10. Exterior body 20. Spiral electrode body 21. Positive plate 22. Negative electrode plate 23. Separator 30. Sealing lid 41. Positive electrode current collector 42. Negative electrode current collector 50. Insulating material

Claims (9)

An electrode body in which positive and negative bipolar plates are wound through a separator and a winding core portion is hollow, a bottomed cylindrical body made of a conductive material, an exterior body that houses the electrode body, and a conductive body A cylindrical battery having a current collector made of a conductive material and interposed between the inner bottom of the exterior body and the electrode body,
Assuming an extended region in which the winding core portion of the electrode body is extended in the winding axis direction, an overlapping region of the extended region and the current collector is a central region of the current collector, and the current collector When the area excluding the central area is the outer edge area,
The current collector is joined to the inner bottom of the exterior body at a plurality of locations,
At least one of the plurality of locations is present in the outer edge region. A cylindrical battery, wherein: The current collector has a plurality of protrusions formed on the outer edge portion toward the inner bottom of the exterior body, and tip regions of the plurality of protrusions are joined to the inner bottom of the exterior body. The cylindrical battery according to claim 1, wherein: The cylindrical battery according to claim 2, wherein the plurality of protrusions are disposed at substantially equal distances from a winding axis center of the electrode body. The cylindrical battery according to any one of claims 1 to 3, wherein an insulator is interposed between the current collector and the inner bottom of the exterior body in the central region. The electrode body and the current collector are joined at a joint portion formed toward the electrode body side in the current collector and an end face of the positive electrode plate or the negative electrode plate,
The cylindrical battery according to any one of claims 2 to 4, wherein the protrusion is formed at a position that does not overlap with the joint in the radial direction of the electrode body. An electrode body forming step for forming an electrode body in which the winding core portion is hollow by arranging the positive and negative bipolar plates to face each other via a separator and winding in this state,
A current collector bonding step of bonding a current collector made of a conductive material to at least one end surface of the electrode body in the winding axis direction;
A storage step of storing the electrode body to which the current collector is joined in a bottomed cylindrical exterior body made of a conductive material, with the current collector side facing the inner bottom;
Joining the current collector to the inner bottom of the exterior body,
Assuming an extended region in which the winding core portion of the electrode body is extended in the winding axis direction, the overlapping region of the extended region and the current collector is a central region of the current collector, and the center of the current collector When the area excluding the area is the outer edge area,
In the joining step, the current collector is joined to the inner bottom of the exterior body at a plurality of locations, and at least one of the plurality of locations is located in the outer edge region. Battery manufacturing method. The method for manufacturing a cylindrical battery according to claim 6, wherein the plurality of protrusions are disposed at substantially equal distances from a winding axis center of the electrode body. The method for manufacturing a cylindrical battery according to claim 6, wherein an insulator is interposed between the current collector and the inner bottom of the exterior body in the central region. The method for manufacturing a cylindrical battery according to any one of claims 6 to 8, wherein, in the joining step, the current collector and the inner bottom of the exterior body are joined using a resistance welding method.

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