JP3757541B2 - Battery case can processing apparatus, processing method and battery - Google Patents

Description

【００２８】
（表１）からわかるように、６０℃で２０日間保存では、１００個の従来電池においても漏液電池は見られなかった。しかし、８５℃で２０日間保存では本発明の実施例の電池は従来電池Ｂおよび円筒形電池と同等の耐漏液性を有するのに対し、従来電池Ａは１００個中１２個漏液した。この漏液電池の漏液経路を調べると、全て長方形部分と円弧部分の境目から漏液していることがわかった。このことより、長円形密閉電池に本発明の溝成形を行なうことにより、長方形部分と円弧部分の境目の歪みを防ぎ、耐漏液性が向上したことがわかった。
【００２９】
【発明の効果】
以上述べたように本発明では、直線部分と円弧部分を有する長円形電池ケース缶において、溝入れ後に、溝成形することにより、上記直線部分と円弧部分の境目の歪みを防ぎ、封口耐圧の高い長円形密閉電池を得ることができ、高温保存時での耐漏液性を向上させるとともに、封口部に備えた安全機構、たとえば電流遮断機構の信頼性を向上することができ、信頼性、安全性に優れた長円形密閉電池を提供することができる。
【図面の簡単な説明】
【図１】本発明の一実施の形態に係る長円形電池ケース缶への封口板載置用の環状支持部の加工装置を示す概略構成図
【図２】同装置の要部の側面図
【図３】同装置と電池ケース缶の関係を示す要部拡大断面図
【図４】（ａ）〜（ｅ）は同装置における電池ケース缶が１８０°回転するまでの過程の一部を順に示したもので、２個の溝形成ローラの変位およびローラ支持レバーに作用する力の説明図
【図５】本発明を実施した長円形電池の構造を示し、（ａ）は平面図、（ｂ）は一部破断した正面図、（ｃ）は側面図
【図６】同電池の縦断面図
【符号の説明】
１０ 長円形電池ケース缶
１４ ケース缶保持部
１７ ケース缶支持部
１７ｃ ケース缶支持部の水平部
１７ｄ ケース缶支持部の垂直部
２３ 溝形成ローラ
２３ｂ ローラ部
２７ 鍔部
４０ 環状支持部
５０ 環状溝[0001]
BACKGROUND OF THE INVENTION
The present invention has a cylindrical shape with a bottom, and the opening is sealed on the inner peripheral surface in the vicinity of the opening of the battery case can having a flat cross-sectional shape perpendicular to the cylindrical center. The present invention relates to a processing device that bulges and forms an annular support for placing and supporting a sealing plate to be stopped, and a structure of an oval battery using an oval battery case can.
[0002]
[Prior art]
In recent years, various electronic devices such as AV devices and personal computers are rapidly becoming portable and cordless, and a sealed battery having high energy density and excellent load characteristics is demanded as a driving power source. Conventionally, as a driving power source for a small and thin portable electronic device, a prismatic battery using a rectangular battery case can having a flat rectangular cross section has been mainly used because it can be easily loaded into the device power supply unit. It was used. This rectangular battery has a configuration in which a group of electrode plates formed by laminating positive and negative electrode plates is housed in a rectangular battery case can and the opening is laser sealed.
[0003]
On the other hand, in recent years, lithium batteries having many features such as high voltage and energy density and long shelf life have been highlighted. However, it is impossible to make a flat lithium battery as a driving power source for a small and thin portable electronic device using the above rectangular battery case can. That is, in the lithium battery, the electrode plate group is formed by winding the positive electrode plate and the negative electrode plate in a spiral shape. Therefore, when this electrode plate group is housed in a battery case can having a square cross-sectional shape, the cross-sectional shapes do not match. Therefore, the electrode plate group is likely to be deformed, and there is a risk of electric leakage when charging and discharging are repeated.
[0004]
In view of this, an oblong battery using an oblong battery case can having a bottomed cylindrical shape and an elliptical shape in which the cross-sectional shape in a direction orthogonal to the cylindrical center is flat has been proposed. This oblong battery is easier to process the battery case can than the square battery, and is highly reliable because it can prevent deformation of the spiral electrode plate group housed in the battery case can. It has various features such as a large battery capacity, and in particular, it is expected that the demand for a drive power source for a small and thin portable electronic device will increase rapidly.
[0005]
[Problems to be solved by the invention]
By the way, in a battery, after inserting a sealing plate with an insulating gasket interposed in the opening of the battery case can, it is generally performed to fold the opening insulating part of the battery case can inward and seal it. . Therefore, an annular support part for placing and supporting the sealing plate is formed on the inner peripheral surface in the vicinity of the opening part of the battery case can, and this annular support part is provided in the vicinity of the opening part in the battery case can. By forming an annular groove along the opening on the outer peripheral surface, it is formed by a portion that bulges on the opposite side of the annular groove. As for the annular support portion, a good processing method suitable for mass production has already been established for cylindrical batteries and rectangular batteries, but an effective processing method suitable for mass production has not yet been proposed for an oblong battery.
[0006]
The present invention provides a processing apparatus capable of forming an annular support for mounting a sealing plate on an oval battery case can with high accuracy and high productivity, and an oval battery using the oval battery case can. This is intended to provide a better processing method for Japanese Patent Application No. 8-55924 related to the same applicant as the applicant of the present invention.
[0007]
[Means for Solving the Problems]
The battery case can processing apparatus according to the present invention has an opening on the outer peripheral surface in the vicinity of the opening in a battery case can having a bottomed cylindrical shape and a flat cross section in a direction perpendicular to the cylindrical center. A processing device for providing an annular support portion for placing and supporting a sealing plate on the inner peripheral surface of the battery case can by a bulging portion on the opposite side of the annular groove by recessing the annular groove along A case can holding portion for holding the battery case can, and an annular flange on the peripheral surface, and is pressurized toward the outer peripheral surface of the battery case held by the case can holding portion, A groove forming roller that forms the annular groove by relative rotation with the flange, and a case can that is disposed in the battery case can and supports the inner periphery of the opening of the battery case can against the pressure applied by the groove forming roller And a flange portion of the groove forming roller is provided on the roller. At least the upper part is formed at a substantially right angle with respect to the surface, and the case can support part is in close contact with the upper inner peripheral surface of the battery case can and faces the upper surface of the flange part of the groove forming roller. Then, the upper part of the annular groove of the battery case can rises at a substantially right angle with respect to the peripheral surface of the battery case, and the inner protrusion of the annular groove pushed inward by the flange of the groove forming roller is predetermined. It is characterized in that it has a vertical part that stops at a position and extends the upper part of the annular groove along the flange shape of the groove forming roller.
[0008]
And when this battery case can processing apparatus processes the annular groove, the groove shape formed in the arc portion and the groove shape formed in the straight portion have at least the annular groove upper portion on which the sealing plate is placed on the inner peripheral surface of the can In the battery in which the sealing plate is placed and sealed, defects such as leakage can be eliminated.
[0009]
Further, by rotating the groove forming roller a plurality of times while pressing the groove case with a predetermined pressure, there is little processing error due to excessive deformation, and a highly accurate battery case can can be configured.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic configuration diagram showing a processing device for an annular support portion for mounting a sealing plate on an oblong battery case can according to an embodiment of the present invention, and FIG. 2 is a side view of a main portion of the device. . In these figures, an oval battery case can 10 having a bottomed cylindrical shape and an elliptical shape in which a cross section perpendicular to the cylindrical center is flat is formed from both sides in the cylindrical direction by a case can support mechanism 13. It is sandwiched and fixed, and is supported so as to be rotatable around the cylinder core. The case can support mechanism 13 contacts the case holder 14 that holds the oval battery case can 10 from the bottom, holds the protrusion 17a that fits into the opening of the battery case can 10, and the opening of the battery case can 10. It is comprised by the case support part 17 which has the step part 17b which touches.
[0011]
The case can support mechanism 13 receives the rotational force from the case can rotation mechanism 18 and rotates the battery case can 10 at a constant speed. The case can rotating mechanism 18 includes a single motor 19 as a rotation drive source, a speed reducer that reduces the rotation of the motor 19, a spline-processed power transmission shaft that transmits the rotation through the speed reducer, and the like. The rotation transmission mechanism 20 and a pulley that fits on the spline shaft and is slidable in the spline shaft direction move the case can holding portion 14 in the forward / backward direction with respect to the battery case can 10 indicated by the arrow, and the rotation transmission mechanism The moving mechanism 21 is configured to apply a rotational force of 20 to the case holding portion 14 and the rotation transmission mechanism 22 that directly transmits the rotational force of the motor 19 to the case support portion 17 via a speed reducer.
[0012]
Therefore, the case can rotating mechanism 18 is adapted to transmit the rotational force of a single motor 19 to the case holding part 14 and the case support part 17 in synchronization. In addition, the case holding unit 14 is moved from the solid line position to the two-dot chain line by the moving mechanism 21 to fit the battery case can 10 supplied to the predetermined position from the bottom portion, and further moves to move the battery case can 10. After the protrusion 17 a of the case support 17 is inserted into the opening, the opening surface of the battery case can 10 is pressed against the step 17 b of the case support 17. Thereafter, the rotational force of the motor 19 is transmitted to the case holding part 14 and the case support part 17 via the both rotation transmission mechanisms 20 and 22, respectively, and the battery case can 10 is rotated at a constant speed.
[0013]
Two groove forming rollers 23 and 24 are provided for forming an annular groove by being pressed against the outer peripheral surface of the battery case can 10 rotated at a constant speed. One groove forming roller 23 is for groove processing in which a flange portion 27 having a width corresponding to the groove width of the annular groove to be formed on the outer peripheral surface of the battery case can 10 is projected from the peripheral surface of the roller portion 23b. The other groove forming roller 24 is for receiving a load having a circular peripheral surface without the flange portion 27. Both the groove forming rollers 23 and 24 are rotatably attached to a bifurcated roller support lever 28, respectively. Note that both the groove forming rollers 23 and 24 may be used for groove processing.
[0014]
As shown in FIG. 2, the groove forming rollers 23 and 24 are positioned so that each roller shaft 23a and 24a forms an isosceles triangle indicated by a two-dot chain line with respect to the center of the support shaft 31 of the roller support lever 28. Arranged and attached to the roller support lever 28. Furthermore, both the groove forming rollers 23 and 24 are at a pitch P larger than the longest dimension L in the direction orthogonal to the cylindrical center of the battery case can 10 and within a range where the both groove forming rollers 23 and 24 do not contact. They are arranged at an interval R that is 1 mm or more, preferably 2 mm or more smaller than the minimum dimension S in the orthogonal direction with respect to 10 cylindrical cores. The roller support lever 28 is attached to a constant pressure and pressure device 29 such as an air cylinder via a connecting member 30 so as to be swingable about a support shaft 31.
[0015]
When the annular groove is formed on the outer peripheral surface of the oval battery case can 10 and the annular support portion is formed on the inner peripheral surface by the processing device, the reinforcing plate 32 is attached to the battery case can 10 as shown in FIG. It is positioned and fixed at a position close to the bottom with respect to the position where the annular support portion is to be formed by fitting from the opening. The reinforcing plate 32 includes two lead wire lead-out holes 33 through which the positive and negative leads 37 and 38 are inserted into a single plate-like body having an outer shape corresponding to the inner peripheral surface of the battery case 10. 34 is formed. Next, formation of the annular groove 50 in the battery case can 10 will be described.
[0016]
As shown in FIG. 3, at least the upper portion of the flange portion 27 of the groove forming roller 23 protrudes in a substantially right angle direction with respect to the peripheral surface of the roller portion 23b, and the case support portion 17 has an upper portion of the flange portion 27. And a horizontal portion 17c opposed to the upper portion of the flange portion 27 through a gap corresponding to the plate thickness of the battery case can 10, and a protruding end of the flange portion 27 and a gap corresponding to the plate thickness of the battery case can 10. 17d, and the groove forming roller 23 is rotated around the battery case can 10 a plurality of times, for example, eight times, while the groove forming roller 23 is pressed against the battery case can 10, thereby successively forming the annular groove 50 deeply. . When the flange portion 27 of the groove forming roller 23 is deformed most deeply, the inner protrusion of the annular groove 50 of the battery case can 10 contacts the vertical portion 17d, and the degree of freedom of deformation is forcibly suppressed. That is, although the deformation state by the forming roller 23 is different between the arc portion and the straight portion of the battery case can 10, at least the shape of the annular groove 50 is substantially the same between the arc portion and the straight portion of the battery case can 10 according to the present embodiment. In the placement and sealing process of the sealing plate 42, the quality can be stabilized and problems such as liquid leakage can be solved.
[0017]
When forming the annular support portion 40 in the above-mentioned oval battery case can, a processing method as shown in FIG. 4 is performed. That is, the oval battery case can 10 is rotated in the direction of the arrow in FIG. 4 while being sandwiched and held by the case holding part 14 and the case support part 17 from both sides in the cylindrical center direction. The groove forming roller 23 is pressed against a predetermined location on the outer peripheral surface. 4A and 4B show states in which the oval battery case can 10 is rotated by 30 °, 45 °, 60 °, and 90 ° with respect to the position shown in FIG. The groove forming roller 23 is always pressed against the oblong battery case 10 with a constant pressure by a pressure device (not shown) such as an air cylinder and acts on the rotation fulcrum of the roller shaft 23a of the groove forming roller 23. In order to simplify the drawing, the pressure F is a length that matches the radius of the groove forming roller 23 and is a vector diagram in the direction connecting the center of the groove forming roller 23 and the center of the oval battery case can 10. It is shown by.
[0018]
Accordingly, as is apparent from FIGS. 4A to 4E, the groove forming roller 23 is pressed against the outer peripheral surface of the oval battery case can 10 that is always rotated at a predetermined position while rolling. When rotated 90 degrees following the shape of the surface, the battery case can 10 is moved forward by a distance D. Thereafter, the groove forming roller 23 is reciprocated so as to advance and retreat within the distance D with respect to the battery case can 10 every time the battery case can 10 rotates 90 °.
[0019]
Therefore, the oval battery manufactured by forming the annular groove 50 and the annular support portion 40 by this processing apparatus has a structure as shown in FIG. 1A is a plan view of an oval battery, FIG. 2B is a partially cutaway front view, and FIG. 3C is a side view. The oval battery is an inner peripheral surface of the battery case can 10. The reinforcing plate 32 is fitted and fixed at a lower position near the annular support portion 40 above the electrode plate group 41 in FIG. The annular support portion 40 is formed by a portion that bulges on the opposite side of the annular groove 50 by forming the annular groove 50 on the outer peripheral surface of the battery case can 10 by the above processing device.
[0020]
Next, the battery configuration will be described in detail.
FIG. 6 is a longitudinal sectional view of an oval battery according to the present invention, which is applied to a thin lithium secondary battery having a width of 40 mm, a height of 48 mm, and a thickness of 8 mm. In FIG. 6, 10 is a battery case can, 41 is an electrode plate group, 42 is a sealing plate, 32 is a reinforcing plate, 38 is a positive electrode lead, 37 is a negative electrode lead, and 42a is a portion of the sealing plate 42 that is joined to the positive electrode lead 38, Reference numeral 60 denotes a gasket.
[0021]
The positive electrode plate is made of lithium cobalt oxide as an active material, and a conductive agent and a binder are mixed and kneaded into this to form a paste mixture on both sides of the core made of aluminum foil, dried and rolled. The aluminum lead is spot-welded to the core. In addition, the negative electrode plate is made of a copper lead using a carbon powder as an active material, mixed with a binder, kneaded, and pasted into a paste made of copper foil. Is spot welded. For the separator, a porous film made of polyethylene is cut wider than the positive electrode plate and the negative electrode plate.
[0022]
These positive and negative electrodes and the separator are wound in a spiral shape, and the end of the separator is fixed with a polypropylene adhesive tape, and then the electrode plate group is pressed from a certain direction to form an oval shape.
[0023]
Thereafter, an annular groove 50 is formed in the case opening.
At that time, the thickness H3 of the case can 10 is 0.4 mm, the thickness H2 of the flange 27 of the roller 23 shown in FIG. 3 and the protrusion dimension L2 are 1 mm, and the inner periphery of the case opening shown in the case can support 17 The dimension L1 from the surface to be supported in close contact with the surface to the vertical portion 17d is 1 mm, the vertical protrusion dimension H1 of the vertical portion 17d is 2.0 mm, the roller 23, the case can holding portion 14 and the case can supporting portion 17 Is set as shown in FIG.
[0024]
Thereafter, the positive electrode lead 38 and the sealing plate 42 are spot-welded, an electrolyte is injected, and then an elliptical lithium secondary battery is formed through the positive electrode lead curve and caulking sealing.
[0025]
In the above description, an example in which groove forming is performed on a lithium secondary battery has been described. However, the same effect can be obtained in other battery systems regardless of the primary battery or the secondary battery.
[0026]
In order to examine the effect of the present invention, a conventional oval sealed battery simply grooved is a conventional battery A, and an oval sealed battery grooved by a receiving die and a punch die after being grooved is a conventional battery B. An oval sealed battery according to an example of the invention was used as an example battery of the present invention. Further, for comparison, a sealed battery having a cylindrical cross section is used as a cylindrical battery, and 100 batteries are prepared, and the number of leaking batteries when stored at 60 ° C. and 85 ° C. for 20 days in a charged state is measured. (Table 1).
[0027]
[Table 1]

[0028]
As can be seen from (Table 1), no leakage batteries were found in 100 conventional batteries when stored at 60 ° C. for 20 days. However, when stored at 85 ° C. for 20 days, the battery of the example of the present invention had the same leakage resistance as the conventional battery B and the cylindrical battery, whereas the conventional battery A leaked 12 out of 100. When the leakage path of this leakage battery was examined, it was found that leakage occurred from the boundary between the rectangular portion and the arc portion. From this, it was found that by performing the groove forming of the present invention on an oval sealed battery, distortion at the boundary between the rectangular portion and the arc portion was prevented, and leakage resistance was improved.
[0029]
【The invention's effect】
As described above, in the present invention, in the oval battery case can having a straight portion and an arc portion, by forming a groove after grooving, distortion of the boundary between the straight portion and the arc portion is prevented, and the sealing pressure resistance is high. An oval sealed battery can be obtained, which improves the leakage resistance during high-temperature storage, and improves the reliability of the safety mechanism provided in the sealing part, for example, the current interruption mechanism. It is possible to provide an oval sealed battery excellent in the above.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing a processing device for an annular support portion for mounting a sealing plate on an oval battery case can according to an embodiment of the present invention. FIG. 2 is a side view of a main part of the device. FIG. 3 is an enlarged cross-sectional view of the main part showing the relationship between the apparatus and the battery case can. FIGS. 4A to 4E sequentially show a part of the process until the battery case can rotates 180 degrees in the apparatus. FIG. 5 is a diagram illustrating the displacement of two groove forming rollers and the force acting on the roller support lever. FIG. 5 shows the structure of an oval battery embodying the present invention, (a) is a plan view, (b) Is a partially broken front view, (c) is a side view [Fig. 6] A longitudinal sectional view of the battery [Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Oval battery case can 14 Case can holding part 17 Case can support part 17c Horizontal part 17d of case can support part Vertical part 23 of case can support part Groove forming roller 23b Roller part 27 Gutter part 40 Annular support part 50 Annular groove

Claims (5)

By forming an annular groove along the opening on the outer peripheral surface in the vicinity of the opening in the battery case can having a cylindrical shape with a bottom and a cross-section in a direction orthogonal to the cylindrical center being flat, A case can holder for holding a battery case can in a processing apparatus in which an annular support portion for mounting and supporting a sealing plate by a bulging portion on the opposite side of the annular groove is provided on an inner peripheral surface of the battery case can And an annular flange on the peripheral surface, pressurized toward the outer peripheral surface of the battery case held by the case can holding portion, and the annular groove is formed by relative rotation between the outer peripheral surface and the flange portion. A groove forming roller to be formed, and a case can supporting portion which is disposed in the battery case can and supports the inner periphery of the opening of the battery case can against the pressing force of the groove forming roller. At least the upper part of the collar is almost straight to the peripheral surface of the roller. The case can support portion is in close contact with the upper inner peripheral surface of the battery case can and faces the upper surface of the protrusion of the groove forming roller so that the upper portion of the annular groove of the battery case can The horizontal part rising substantially perpendicular to the peripheral surface and the inner protrusion of the annular groove pushed inward by the flange part of the groove forming roller are stopped in place, and the upper part of the annular groove is fixed to the groove forming roller. An apparatus for processing a battery case can, comprising a vertical portion that follows the shape of the collar portion. 2. The battery case can processing apparatus according to claim 1, wherein the case can holding part and the case can supporting part are integrally rotated around a cylindrical center of the battery case can. 2. The battery case can according to claim 1, wherein the battery case can is fixed by a case can holding part and a case can support part, and the case peripheral surface is rotated while pressing the groove forming roller against the case. Processing equipment. By using the battery case can processing apparatus according to claim 1, by applying a plurality of times of relative rotational pressing of the battery case and the flange portion of the groove forming roller in contact with the battery case by a predetermined pressure of the groove forming roller, A method for processing a battery case can, comprising forming an annular groove. A battery comprising the battery case can processing apparatus according to claim 1.

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